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Dandan M, Han J, Mann S, Kim R, Li K, Mohammed H, Chuang JC, Zhu K, Billin AN, Huss RS, Chung C, Myers RP, Hellerstein M. Acetyl-CoA carboxylase inhibitor increases LDL-apoB production rate in NASH with cirrhosis: prevention by fenofibrate. J Lipid Res 2023; 64:100339. [PMID: 36737040 PMCID: PMC10017426 DOI: 10.1016/j.jlr.2023.100339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 01/27/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Treatment with acetyl-CoA carboxylase inhibitors (ACCi) in nonalcoholic steatohepatitis (NASH) may increase plasma triglycerides (TGs), with variable changes in apoB concentrations. ACC is rate limiting in de novo lipogenesis and regulates fatty acid oxidation, making it an attractive therapeutic target in NASH. Our objectives were to determine the effects of the ACCi, firsocostat, on production rates of plasma LDL-apoB in NASH and the effects of combined therapy with fenofibrate. Metabolic labeling with heavy water and tandem mass spectrometric analysis of LDL-apoB enrichments was performed in 16 NASH patients treated with firsocostat for 12 weeks and in 29 NASH subjects treated with firsocostat and fenofibrate for 12 weeks. In NASH on firsocostat, plasma TG increased significantly by 17% from baseline to week 12 (P = 0.0056). Significant increases were also observed in LDL-apoB fractional replacement rate (baseline to week 12: 31 ± 20.2 to 46 ± 22.6%/day, P = 0.03) and absolute synthesis rate (ASR) (30.4-45.2 mg/dl/day, P = 0.016) but not plasma apoB concentrations. The effect of firsocostat on LDL-apoB ASR was restricted to patients with cirrhosis (21.0 ± 9.6 at baseline and 44.2 ± 17 mg/dl/day at week 12, P = 0.002, N = 8); noncirrhotic patients did not change (39.8 ± 20.8 and 46.3 ± 14.8 mg/dl/day, respectively, P = 0.51, N = 8). Combination treatment with fenofibrate and firsocostat prevented increases in plasma TG, LDL-apoB fractional replacement rate, and ASR. In summary, in NASH with cirrhosis, ACCi treatment increases LDL-apoB100 production rate and this effect can be prevented by concurrent fenofibrate therapy.
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Affiliation(s)
- Mohamad Dandan
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Julia Han
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Sabrina Mann
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Rachael Kim
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Kelvin Li
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Hussein Mohammed
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA
| | | | - Kaiyi Zhu
- Gilead Sciences, Inc, Foster City, CA, USA
| | | | | | | | | | - Marc Hellerstein
- Department of Nutritional Sciences and Toxicology, Graduate Program in Metabolic Biology, University of California at Berkeley, Berkeley, CA, USA.
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2
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Lawitz EJ, Bhandari BR, Ruane PJ, Kohli A, Harting E, Ding D, Chuang JC, Huss RS, Chung C, Myers RP, Loomba R. Fenofibrate Mitigates Hypertriglyceridemia in Nonalcoholic Steatohepatitis Patients Treated With Cilofexor/Firsocostat. Clin Gastroenterol Hepatol 2023; 21:143-152.e3. [PMID: 34999207 DOI: 10.1016/j.cgh.2021.12.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/21/2021] [Accepted: 12/24/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Patients with advanced fibrosis due to nonalcoholic steatohepatitis (NASH) are at high risk of morbidity and mortality. We previously found that a combination of the farnesoid X receptor agonist cilofexor (CILO) and the acetyl-CoA carboxylase inhibitor firsocostat (FIR) improved liver histology and biomarkers in NASH with advanced fibrosis but was associated with hypertriglyceridemia. We evaluated the safety and efficacy of icosapent ethyl (Vascepa) and fenofibrate to mitigate triglyceride elevations in patients with NASH treated with CILO and FIR. METHODS Patients with NASH with elevated triglycerides (≥150 and <500 mg/dL) were randomized to Vascepa 2 g twice daily (n = 33) or fenofibrate 145 mg daily (n = 33) for 2 weeks, followed by the addition of CILO 30 mg and FIR 20 mg daily for 6 weeks. Safety, lipids, and liver biochemistry were monitored. RESULTS All treatments were well-tolerated; most treatment-emergent adverse events were Grade 1 to 2 severity, and there were no discontinuations due to adverse events. At baseline, median (interquartile range [IQR]) triglycerides were similar in the Vascepa and fenofibrate groups (median, 177 [IQR, 154-205] vs 190 [IQR, 144-258] mg/dL, respectively). Median changes from baseline in triglycerides for Vascepa vs fenofibrate after 2 weeks of pretreatment were -12 mg/dL (IQR, -33 to 7 mg/dL; P = .09) vs -32 mg/dL (IQR, -76 to 6 mg/dL; P = .012) and at 6 weeks were +41 mg/dL (IQR, 16-103 mg/dL; P < .001) vs -2 mg/dL (IQR, -42 to 54 mg/dL; P = .92). In patients with baseline triglycerides <250 mg/dL, fenofibrate was more effective vs Vascepa in mitigating triglyceride increases after 6 weeks of combination treatment (+6 vs +39 mg/dL); similar trends were observed in patients with baseline triglycerides ≥250 mg/d (-61 vs +99 mg/dL). CONCLUSIONS In patients with NASH with hypertriglyceridemia treated with CILO and FIR, fenofibrate was safe and effectively mitigated increases in triglycerides associated with acetyl-CoA carboxylase inhibition. CLINICALTRIALS gov, Number: NCT02781584.
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Affiliation(s)
- Eric J Lawitz
- Texas Liver Institute and University of Texas Health, San Antonio, Texas
| | | | - Peter J Ruane
- Ruane Clinical Research Group, Inc, Los Angeles, California
| | | | | | - Dora Ding
- Gilead Sciences, Inc, Foster City, California
| | | | - Ryan S Huss
- Gilead Sciences, Inc, Foster City, California
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3
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Smirnova E, Muthiah MD, Narayan N, Siddiqui MS, Puri P, Luketic VA, Contos MJ, Idowu M, Chuang JC, Billin AN, Huss RS, Myers RP, Boyett S, Seneshaw M, Min HK, Mirshahi F, Sanyal AJ. Metabolic reprogramming of the intestinal microbiome with functional bile acid changes underlie the development of NAFLD. Hepatology 2022; 76:1811-1824. [PMID: 35561146 PMCID: PMC9653520 DOI: 10.1002/hep.32568] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/19/2022] [Accepted: 05/03/2022] [Indexed: 01/02/2023]
Abstract
BACKGROUND AND AIMS Bile acids are hepatic metabolites and have many properties considered to be relevant to the pathophysiology of NAFLD. Circulating levels of the intestinal microbiome-modified bile acid deoxycholate are increased in cirrhosis. APPROACH AND RESULTS To further elucidate the role of bile acids and intestinal microbiota linked to bile acids in progressively severe NAFLD, a multiomic study of feces including 16S rRNA sequencing, microbial transcriptomics and metabolomics was performed in a cohort with varying phenotypes of NAFLD. Several bile acids of microbial origin derived from deoxycholic acid (DCA) (glycodeoxycholate, 7-ketodeoxycholic acid, dehydrocholic acid) increased with disease activity and fibrosis stage. These were linked to increased expression of microbial bile salt hydrolase, bile acid operon (BaiCD) and hydroxysteroid dehydrogenases (hdhA) required for DCA and downstream metabolite synthesis providing a mechanistic basis for altered bile acid profiles with disease progression. Bacteroidetes and several genera of Lachnospiraceae family containing DCA generating genes increased with increasing disease severity, whereas several potentially beneficial microbes sensitive to antibacterial effects of DCA e.g., Ruminococcaceae were decreased. The clinical relevance of these data was confirmed in an independent cohort enrolled in a clinical trial for NASH where at entry DCA and its conjugates were associated with advanced fibrosis. In patients treated with placebo, DCA declined in those with fibrosis regression and increased in those with fibrosis progression. DCA rose further in those with compensated cirrhosis when they experienced decompensation. CONCLUSIONS These findings demonstrate a role for bile acids and the bile acid dependent microbiome in the development and progression of NAFLD and set the stage to leverage these findings for NASH biomarker development and for therapeutics.
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Affiliation(s)
- Ekaterina Smirnova
- Department of BiostatisticsVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Mark D Muthiah
- Division of Gastroenterology and HepatologyNational University Health SystemSingapore.,Yong Loo Lin School of MedicineNational University of SingaporeSingapore
| | | | - Mohamad S Siddiqui
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Puneet Puri
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Velimir A Luketic
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Melissa J Contos
- Department of PathologyVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Michael Idowu
- Department of PathologyVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | | | | | - Ryan S Huss
- Gilead Sciences Inc.Foster CityCaliforniaUSA
| | | | - Sherry Boyett
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Mulugeta Seneshaw
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Hae-Ki Min
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Faridodin Mirshahi
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
| | - Arun J Sanyal
- Division of Gastroenterology, Hepatology and NutritionDepartment of Internal MedicineVirginia Commonwealth University School of MedicineRichmondVirginiaUSA
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Celen C, Chuang JC, Shen S, Li L, Maggiore G, Jia Y, Luo X, Moore A, Wang Y, Otto JE, Collings CK, Wang Z, Sun X, Nassour I, Park J, Ghaben A, Wang T, Wang SC, Scherer PE, Kadoch C, Zhu H. Arid1a loss potentiates pancreatic β-cell regeneration through activation of EGF signaling. Cell Rep 2022; 41:111581. [DOI: 10.1016/j.celrep.2022.111581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/18/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
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5
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Lawitz EJ, Li KW, Nyangau E, Field TJ, Chuang JC, Billin A, Wang L, Wang Y, Huss RS, Chung C, Subramanian GM, Myers RP, Hellerstein MK. Elevated de novo lipogenesis, slow liver triglyceride turnover and clinical correlations in nonalcoholic steatohepatitis patients. J Lipid Res 2022; 63:100250. [PMID: 35835205 PMCID: PMC9424583 DOI: 10.1016/j.jlr.2022.100250] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/28/2022] [Accepted: 07/02/2022] [Indexed: 11/19/2022] Open
Abstract
De novo lipogenesis (DNL) converts carbon substrates to lipids. Increased hepatic DNL could contribute to pathogenic liver triglyceride accumulation in nonalcoholic steatohepatitis (NASH) and therefore may be a potential target for pharmacological intervention. Here, we measured hepatic DNL using heavy water in 123 NASH patients with fibrosis or cirrhosis, calculated the turnover of hepatic triglycerides to allow repeat labeling studies and determined the associations of hepatic DNL with metabolic, fibrotic, and imaging markers. We found that hepatic DNL was higher in fibrotic NASH patients [median (IQR), 40.7% contribution to palmitate (32.1, 47.5), n=103] than has been previously reported in healthy volunteers and remained elevated [median (IQR), 36.8% (31.0, 44.5), n=20] in patients with cirrhosis, despite lower liver fat content. We also showed that turnover of intrahepatic triglyceride pools was slow (t½ >10 days). Furthermore, DNL contribution was determined to be independent of liver stiffness by magnetic resonance imaging, but was positively associated with the number of large very low-density lipoprotein (VLDL) particles, the size of VLDL, the lipoprotein insulin resistance score, and levels of ApoB100 (r=0.6, p=0.07), and trended towards negative associations with the fibrosis markers FIB-4, FibroSure and APRI. Finally, we found treatment with the acetyl-CoA carboxylase inhibitor firsocostat reduced hepatic DNL at 4 and 12 weeks, using a correction model for residual label that accounts for hepatic triglyceride turnover. Taken together, these data support an important pathophysiological role for elevated hepatic DNL in NASH, and demonstrate that response to pharmacological agents targeting DNL can be correlated with pre-treatment DNL.
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Affiliation(s)
- Eric J Lawitz
- Texas Liver Institute, University of Texas Health Science Center San Antonio, San Antonio, Texas, USA
| | - Kelvin W Li
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, California, USA
| | - Edna Nyangau
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, California, USA
| | - Tyler John Field
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, California, USA
| | | | | | - Lulu Wang
- Gilead Sciences, Inc., Foster City, Californi, USA
| | - Ya Wang
- Gilead Sciences, Inc., Foster City, Californi, USA
| | - Ryan S Huss
- Gilead Sciences, Inc., Foster City, Californi, USA
| | - Chuhan Chung
- Gilead Sciences, Inc., Foster City, Californi, USA
| | | | | | - Marc K Hellerstein
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, California, USA.
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6
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Sharpton SR, Podlaha O, Chuang JC, Gindin Y, Myers RP, Loomba R. Changes in the gut microbiome associated with liver stiffness improvement in nonalcoholic steatohepatitis. Therap Adv Gastroenterol 2022; 15:17562848221098243. [PMID: 35601801 PMCID: PMC9121469 DOI: 10.1177/17562848221098243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 04/13/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Longitudinal studies are needed to decipher mechanistic links between the gut microbiome and nonalcoholic steatohepatitis (NASH). We examined shifts in the gut microbiome in persons with NASH with improvement in liver stiffness measurement (LSM) by magnetic resonance (MR) elastography. METHODS Gut microbial profiling was performed at baseline and study completion (24 weeks) using 16 S rRNA gene sequencing in 69 adults with biopsy-confirmed NASH and significant fibrosis (stages 2-3) enrolled in a multi-center randomized controlled trial evaluating selonsertib alone or in combination with simtuzumab. Differential abundance of bacterial taxa at baseline and end of study were examined in participants with and without longitudinal improvement in LSM. Gut microbial shifts that correlated with secondary outcomes, including reduction in MR imaging-derived proton density fat faction (MRI-PDFF) and histologic fibrosis regression were evaluated. Fecal samples from 32 healthy adults were profiled and genus-level multidimensional scaling was used to determine if microbial shifts in persons with NASH improvement represented a shift toward a healthy gut microbiome. RESULTS Shifts in abundance of 36 bacterial taxa including Lactobacillus (log2FC = -4.51, FDR < 0.001), Enterococcus (log2FC = -6.72, FDR < 0.001), and Megasphaera (log2FC = 7.74, FDR < 0.001) were associated with improvement in LSM. Improvement in LSM was associated with microbial shifts toward healthy reference (p = 0.05). Significant shifts in 10 and 12 bacterial taxa were associated with improvement in LSM in addition to MRI-PDFF and fibrosis regression, respectively, indicating consistent taxonomic changes across multiple clinical endpoints. CONCLUSION Longitudinal changes in the gut microbiota are observed in adults with NASH and clinical improvement and represent a shift toward a healthy microbiome.
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Affiliation(s)
- Suzanne R. Sharpton
- Division of Gastroenterology, Department of
Medicine, University of California, San Diego, La Jolla, CA, USA,NAFLD Research Center, Division of
Gastroenterology, University of California, San Diego, La Jolla, CA,
USA
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7
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Loomba R, Noureddin M, Kowdley KV, Kohli A, Sheikh A, Neff G, Bhandari BR, Gunn N, Caldwell SH, Goodman Z, Wapinski I, Resnick M, Beck AH, Ding D, Jia C, Chuang JC, Huss RS, Chung C, Subramanian GM, Myers RP, Patel K, Borg BB, Ghalib R, Kabler H, Poulos J, Younes Z, Elkhashab M, Hassanein T, Iyer R, Ruane P, Shiffman ML, Strasser S, Wong VWS, Alkhouri N. Combination Therapies Including Cilofexor and Firsocostat for Bridging Fibrosis and Cirrhosis Attributable to NASH. Hepatology 2021; 73:625-643. [PMID: 33169409 DOI: 10.1002/hep.31622] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/19/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Advanced fibrosis attributable to NASH is a leading cause of end-stage liver disease. APPROACH AND RESULTS In this phase 2b trial, 392 patients with bridging fibrosis or compensated cirrhosis (F3-F4) were randomized to receive placebo, selonsertib 18 mg, cilofexor 30 mg, or firsocostat 20 mg, alone or in two-drug combinations, once-daily for 48 weeks. The primary endpoint was a ≥1-stage improvement in fibrosis without worsening of NASH between baseline and 48 weeks based on central pathologist review. Exploratory endpoints included changes in NAFLD Activity Score (NAS), liver histology assessed using a machine learning (ML) approach, liver biochemistry, and noninvasive markers. The majority had cirrhosis (56%) and NAS ≥5 (83%). The primary endpoint was achieved in 11% of placebo-treated patients versus cilofexor/firsocostat (21%; P = 0.17), cilofexor/selonsertib (19%; P = 0.26), firsocostat/selonsertib (15%; P = 0.62), firsocostat (12%; P = 0.94), and cilofexor (12%; P = 0.96). Changes in hepatic collagen by morphometry were not significant, but cilofexor/firsocostat led to a significant decrease in ML NASH CRN fibrosis score (P = 0.040) and a shift in biopsy area from F3-F4 to ≤F2 fibrosis patterns. Compared to placebo, significantly higher proportions of cilofexor/firsocostat patients had a ≥2-point NAS reduction; reductions in steatosis, lobular inflammation, and ballooning; and significant improvements in alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, bile acids, cytokeratin-18, insulin, estimated glomerular filtration rate, ELF score, and liver stiffness by transient elastography (all P ≤ 0.05). Pruritus occurred in 20%-29% of cilofexor versus 15% of placebo-treated patients. CONCLUSIONS In patients with bridging fibrosis and cirrhosis, 48 weeks of cilofexor/firsocostat was well tolerated, led to improvements in NASH activity, and may have an antifibrotic effect. This combination offers potential for fibrosis regression with longer-term therapy in patients with advanced fibrosis attributable to NASH.
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Affiliation(s)
- Rohit Loomba
- NAFLD Research CenterUniversity of California at San DiegoLa JollaCA
| | | | | | | | | | - Guy Neff
- Covenant Research, LLCSarasotaFL
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Reem Ghalib
- Texas Clinical Research InstituteArlingtonTX
| | | | - John Poulos
- Cumberland Research AssociatesFayettevilleNC
| | | | | | | | | | - Peter Ruane
- Ruane Medical and Liver Health InstituteLos AngelesCA
| | | | - Simone Strasser
- Royal Prince Alfred Hospital and The University of SydneyCamperdownNew South WalesAustralia
| | - Vincent Wai-Sun Wong
- Department of Medicine and TherapeuticsThe Chinese University of Hong KongHong KongHong Kong
| | - Naim Alkhouri
- Texas Liver InstituteUT Health San AntonioSan AntonioTX
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8
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Wang Z, Chen K, Jia Y, Chuang JC, Sun X, Lin YH, Celen C, Li L, Huang F, Liu X, Castrillon DH, Wang T, Zhu H. Dual ARID1A/ARID1B loss leads to rapid carcinogenesis and disruptive redistribution of BAF complexes. ACTA ACUST UNITED AC 2020; 1:909-922. [PMID: 34386776 DOI: 10.1038/s43018-020-00109-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SWI/SNF chromatin remodelers play critical roles in development and cancer. The causal links between SWI/SNF complex disassembly and carcinogenesis are obscured by redundancy between paralogous components. Canonical cBAF-specific paralogs ARID1A and ARID1B are synthetic lethal in some contexts, but simultaneous mutations in both ARID1s are prevalent in cancer. To understand if and how cBAF abrogation causes cancer, we examined the physiologic and biochemical consequences of ARID1A/ARID1B loss. In double knockout liver and skin, aggressive carcinogenesis followed de-differentiation and hyperproliferation. In double mutant endometrial cancer, add-back of either induced senescence. Biochemically, residual cBAF subcomplexes resulting from loss of ARID1 scaffolding were unexpectedly found to disrupt polybromo containing pBAF function. 37 of 69 mutations in the conserved scaffolding domains of ARID1 proteins observed in human cancer caused complex disassembly, partially explaining their mutation spectra. ARID1-less, cBAF-less states promote carcinogenesis across tissues, and suggest caution against paralog-directed therapies for ARID1-mutant cancer.
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Affiliation(s)
- Zixi Wang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kenian Chen
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390
| | - Yuemeng Jia
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen-Chieh Chuang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xuxu Sun
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yu-Hsuan Lin
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Cemre Celen
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lin Li
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Fang Huang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Liu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Diego H Castrillon
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tao Wang
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390
| | - Hao Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Caussy C, Chuang JC, Billin A, Hu T, Wang Y, Subramanian GM, Djedjos CS, Myers RP, Dennis EA, Loomba R. Plasma eicosanoids as noninvasive biomarkers of liver fibrosis in patients with nonalcoholic steatohepatitis. Therap Adv Gastroenterol 2020; 13:1756284820923904. [PMID: 32523627 PMCID: PMC7257854 DOI: 10.1177/1756284820923904] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/23/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Eicosanoid and related docosanoid polyunsaturated fatty acids (PUFAs) and their oxygenated derivatives have been proposed as noninvasive lipidomic biomarkers of nonalcoholic steatohepatitis (NASH). Therefore, we investigated associations between plasma eicosanoids and liver fibrosis to evaluate their utility in diagnosing and monitoring NASH-related fibrosis. METHODS Our analysis used baseline eicosanoid data from 427 patients with biopsy-confirmed nonalcoholic fatty liver disease (NAFLD), and longitudinal measurements along with liver fibrosis staging from 63 patients with NASH and stage 2/3 fibrosis followed for 24 weeks in a phase II trial. RESULTS At baseline, four eicosanoids were significantly associated with liver fibrosis stage: 11,12-DIHETE, tetranor 12-HETE, adrenic acid, and 14, 15-DIHETE. Over 24 weeks of follow up, a combination of changes in seven eicosanoids [5-HETE, 7,17-DHDPA, adrenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), 16-HDOHE, and 9-HODE) had good diagnostic accuracy for the prediction of ⩾1 stage improvement in fibrosis (AUROC: 0.74; 95% CI: 0.62-0.87), and a combination of four eicosanoids (7,17-DHDPA, 14,15-DIHETRE, 9-HOTRE, and free adrenic acid) accurately predicted improvement in hepatic collagen content (AUROC: 0.72; 95% CI: 0.50-0.77). CONCLUSION This study provides preliminary evidence that plasma eicosanoids may serve as noninvasive biomarkers of liver fibrosis and may predict liver fibrosis improvement in NASH.
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Affiliation(s)
- Cyrielle Caussy
- Univ Lyon, CarMen Laboratory, INSERM, INRA, INSA
Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France,Hospices Civils de Lyon, Département
Endocrinologie, Diabète et Nutrition, Hôpital Lyon Sud, Pierre-Bénite,
France
| | | | | | - Tao Hu
- Gilead Sciences, Inc., Foster City, CA,
USA
| | - Ya Wang
- Gilead Sciences, Inc., Foster City, CA,
USA
| | | | | | | | - Edward A. Dennis
- Department of Pharmacology and Department of
Chemistry and Biochemistry, University of California San Diego, 9500 Gilman
Drive, MC 0601, La Jolla, CA 92093-0601, USA
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10
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Wang SC, Nassour I, Xiao S, Zhang S, Luo X, Lee J, Li L, Sun X, Nguyen LH, Chuang JC, Peng L, Daigle S, Shen J, Zhu H. SWI/SNF component ARID1A restrains pancreatic neoplasia formation. Gut 2019; 68:1259-1270. [PMID: 30315093 PMCID: PMC6499717 DOI: 10.1136/gutjnl-2017-315490] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVE ARID1A is commonly mutated in pancreatic ductal adenocarcinoma (PDAC), but the functional effects of ARID1A mutations in the pancreas are unclear. Understanding the molecular mechanisms that drive PDAC formation may lead to novel therapies. DESIGN Concurrent conditional Arid1a deletion and Kras activation mutations were modelled in mice. Small-interfering RNA (siRNA) and CRISPR/Cas9 were used to abrogate ARID1A in human pancreatic ductal epithelial cells. RESULTS We found that pancreas-specific Arid1a loss in mice was sufficient to induce inflammation, pancreatic intraepithelial neoplasia (PanIN) and mucinous cysts. Concurrent Kras activation accelerated the development of cysts that resembled intraductal papillary mucinous neoplasm. Lineage-specific Arid1a deletion confirmed compartment-specific tumour-suppressive effects. Duct-specific Arid1a loss promoted dilated ducts with occasional cyst and PDAC formation. Heterozygous acinar-specific Arid1a loss resulted in accelerated PanIN and PDAC formation with worse survival. RNA-seq showed that Arid1a loss induced gene networks associated with Myc activity and protein translation. ARID1A knockdown in human pancreatic ductal epithelial cells induced increased MYC expression and protein synthesis that was abrogated with MYC knockdown. ChIP-seq against H3K27ac demonstrated an increase in activated enhancers/promoters. CONCLUSIONS Arid1a suppresses pancreatic neoplasia in a compartment-specific manner. In duct cells, this process appears to be associated with MYC-facilitated protein synthesis.
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Affiliation(s)
- Sam C Wang
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ibrahim Nassour
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shu Xiao
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shuyuan Zhang
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xin Luo
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of BioInformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeon Lee
- Department of BioInformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lin Li
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xuxu Sun
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Liem H Nguyen
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Jen-Chieh Chuang
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lan Peng
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Jeanne Shen
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Hao Zhu
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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11
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Gupta D, Chuang JC, Mani BK, Shankar K, Rodriguez JA, Osborne-Lawrence S, Metzger NP, Zigman JM. β1-adrenergic receptors mediate plasma acyl-ghrelin elevation and depressive-like behavior induced by chronic psychosocial stress. Neuropsychopharmacology 2019; 44:1319-1327. [PMID: 30758330 PMCID: PMC6785135 DOI: 10.1038/s41386-019-0334-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/06/2018] [Accepted: 02/04/2019] [Indexed: 12/19/2022]
Abstract
The ghrelin system is a key component of the mood and metabolic responses to chronic psychosocial stress. For example, circulating acyl-ghrelin rises in several rodent and human stress models, administered acyl-ghrelin induces antidepressant-like behavioral responses in mice, and mice with deleted ghrelin receptors (GHSRs) exhibit exaggerated depressive-like behaviors, changed eating behaviors, and altered metabolism in response to chronic stress. However, the mechanisms mediating stress-induced rises in ghrelin are unknown and ghrelin's antidepressant-like efficacy in the setting of chronic stress is incompletely characterized. Here, we used a pharmacological approach in combination with a 10-day chronic social defeat stress (CSDS) model in male mice to investigate whether the sympathoadrenal system is involved in the ghrelin response to stress. We also examined the antidepressant-like efficacy of administered ghrelin and the synthetic GHSR agonist GHRP-2 during and/or after CSDS. We found that administration of the β1-adrenergic receptor (β1AR) blocker atenolol during CSDS blunts the elevation of plasma acyl-ghrelin and exaggerates depressive-like behavior. Neither acute injection of acyl-ghrelin directly following CSDS nor its chronic administration during or after CSDS nor chronic delivery of GHRP-2 during and after CSDS improved stress-induced depressive-like behavior. Thus, β1ARs drive the acyl-ghrelin response to CSDS, but supplementing the natural increases in acyl-ghrelin with exogenous acyl-ghrelin or GHSR agonist does not further enhance the antidepressant-like actions of the endogenous ghrelin system in the setting of CSDS.
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Affiliation(s)
- Deepali Gupta
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Jen-Chieh Chuang
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Bharath K. Mani
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Kripa Shankar
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Juan A. Rodriguez
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Sherri Osborne-Lawrence
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Nathan P. Metzger
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Jeffrey M. Zigman
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA ,0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Endocrinology, UT Southwestern Medical Center, Dallas, TX USA ,0000 0000 9482 7121grid.267313.2Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA
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12
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Moore A, Wu L, Chuang JC, Sun X, Luo X, Gopal P, Li L, Celen C, Zimmer M, Zhu H. Arid1a Loss Drives Nonalcoholic Steatohepatitis in Mice Through Epigenetic Dysregulation of Hepatic Lipogenesis and Fatty Acid Oxidation. Hepatology 2019; 69:1931-1945. [PMID: 30584660 PMCID: PMC6461494 DOI: 10.1002/hep.30487] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 11/28/2018] [Indexed: 01/05/2023]
Abstract
Nonalcoholic steatohepatitis (NASH) is a rapidly growing cause of chronic liver damage, cirrhosis, and hepatocellular carcinoma. How fatty liver pathogenesis is subject to epigenetic regulation is unknown. We hypothesized that chromatin remodeling is important for the pathogenesis of fatty liver disease. AT-rich interactive domain-containing protein 1A (ARID1A), a DNA-binding component of the SWItch/sucrose nonfermentable adenosine triphosphate-dependent chromatin-remodeling complex, contributes to nucleosome repositioning and access by transcriptional regulators. Liver-specific deletion of Arid1a (Arid1a liver knockout [LKO]) caused the development of age-dependent fatty liver disease in mice. Transcriptome analysis revealed up-regulation of lipogenesis and down-regulation of fatty acid oxidation genes. As evidence of direct regulation, ARID1A demonstrated direct binding to the promoters of many of these differentially regulated genes. Additionally, Arid1a LKO mice were more susceptible to high-fat diet-induced liver steatosis and fibrosis. We deleted Pten in combination with Arid1a to synergistically drive fatty liver progression. Inhibition of lipogenesis using CAT-2003, a potent sterol regulatory element-binding protein inhibitor, mediated improvements in markers of fatty liver disease progression in this Arid1a/Pten double knockout model. Conclusion: ARID1A plays a role in the epigenetic regulation of hepatic lipid homeostasis, and its suppression contributes to fatty liver pathogenesis. Combined Arid1a and Pten deletion shows accelerated fatty liver disease progression and is a useful mouse model for studying therapeutic strategies for NASH.
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Affiliation(s)
- Austin Moore
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Linwei Wu
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen-Chieh Chuang
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xuxu Sun
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Luo
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Purva Gopal
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lin Li
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Cemre Celen
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Michael Zimmer
- Biology, Catabasis Pharmaceuticals, Cambridge, MA 02139, USA
| | - Hao Zhu
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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13
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Kjalarsdottir L, Tersey SA, Vishwanath M, Chuang JC, Posner BA, Mirmira RG, Repa JJ. 1,25-Dihydroxyvitamin D 3 enhances glucose-stimulated insulin secretion in mouse and human islets: a role for transcriptional regulation of voltage-gated calcium channels by the vitamin D receptor. J Steroid Biochem Mol Biol 2019; 185:17-26. [PMID: 30071248 DOI: 10.1016/j.jsbmb.2018.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 06/26/2018] [Accepted: 07/06/2018] [Indexed: 12/12/2022]
Abstract
AIM Vitamin D deficiency in rodents negatively affects glucose-stimulated insulin secretion (GSIS) and human epidemiological studies connect poor vitamin D status with type 2 diabetes. Previous studies performed primarily in rat islets have shown that vitamin D can enhance GSIS. However the molecular pathways linking vitamin D and insulin secretion are currently unknown. Therefore, experiments were undertaken to elucidate the transcriptional role(s) of the vitamin D receptor (VDR) in islet function. METHODS Human and mouse islets were cultured with vehicle or 1,25-dihydroxyvitamin-D3 (1,25D3) and then subjected to GSIS assays. Insulin expression, insulin content, glucose uptake and glucose-stimulated calcium influx were tested. Microarray analysis was performed. In silico analysis was used to identify VDR response elements (VDRE) within target genes and their activity was tested using reporter assays. RESULTS Vdr mRNA is abundant in islets and Vdr expression is glucose-responsive. Preincubation of mouse and human islets with 1,25D3 enhances GSIS and increases glucose-stimulated calcium influx. Microarray analysis identified the R-type voltage-gated calcium channel (VGCC) gene, Cacna1e, which is highly upregulated by 1,25D3 in human and mouse islets and contains a conserved VDRE in intron 7. Results from GSIS assays suggest that 1,25D3 might upregulate a variant of R-type VGCC that is resistant to chemical inhibition. CONCLUSION These results suggest that the role of 1,25D3 in regulating calcium influx acts through the R-Type VGCC during GSIS, thereby modulating the capacity of beta cells to secrete insulin.
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Affiliation(s)
- Lilja Kjalarsdottir
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States.
| | - Sarah A Tersey
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Mridula Vishwanath
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Jen-Chieh Chuang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Bruce A Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Raghavendra G Mirmira
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Joyce J Repa
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States.
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14
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Lütjohann D, Lopez AM, Chuang JC, Kerksiek A, Turley SD. Identification of Correlative Shifts in Indices of Brain Cholesterol Metabolism in the C57BL6/Mecp2 tm1.1Bird Mouse, a Model for Rett Syndrome. Lipids 2018; 53:363-373. [PMID: 29770459 DOI: 10.1002/lipd.12041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/26/2018] [Accepted: 04/03/2018] [Indexed: 01/14/2023]
Abstract
Rett syndrome (RS) is a pervasive neurodevelopmental disorder resulting from loss-of-function mutations in the X-linked gene methyl-Cpg-binding protein 2 (MECP2). Using a well-defined model for RS, the C57BL6/Mecp2tm1.1Bird mouse, we have previously found a moderate but persistently lower rate of cholesterol synthesis, measured in vivo, in the brains of Mecp2-/y mice, starting from about the third week after birth. There was no genotypic difference in the total cholesterol concentration throughout the brain at any age. This raised the question of whether the lower rate of cholesterol synthesis in the mutants was balanced by a fall in the rate at which cholesterol was converted via cholesterol 24-hydroxylase (Cyp46A1) to 24S-hydroxycholesterol (24S-OHC), the principal route through which cholesterol is ordinarily removed from the brain. Here, we show that while there were no genotypic differences in the concentrations in plasma and liver of three cholesterol precursors (lanosterol, lathosterol, and desmosterol), two plant sterols (sitosterol and campesterol), and two oxysterols (27-hydroxycholesterol [27-OHC] and 24S-OHC), the brains of the Mecp2 -/y mice had significantly lower concentrations of all three cholesterol precursors, campesterol, and both oxysterols, with the level of 24S-OHC being ~20% less than in their Mecp2 +/y controls. Together, these data suggest that coordinated regulation of cholesterol synthesis and catabolism in the central nervous system is maintained in this model for RS. Furthermore, we speculate that the adaptive changes in these two pathways conceivably resulted from a shift in the permeability of the blood-brain barrier as implied by the significantly lower campesterol and 27-OHC concentrations in the brains of the Mecp2-/y mice.
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Affiliation(s)
- Dieter Lütjohann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9151, USA
| | - Jen-Chieh Chuang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390-9060, USA
| | - Anja Kerksiek
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9151, USA
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15
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Lopez AM, Chuang JC, Turley SD. Impact of loss of SOAT2 function on disease progression in the lysosomal acid lipase-deficient mouse. Steroids 2018; 130:7-14. [PMID: 29246491 PMCID: PMC5760480 DOI: 10.1016/j.steroids.2017.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 01/27/2023]
Abstract
Although only a small proportion of cholesterol in the body is esterified, in several diseases marked expansion of the esterified cholesterol (EC) pool occurs. These include Wolman disease (WD) and Cholesteryl Ester Storage Disease (CESD) which both result from mutations in LIPA, the gene that encodes lysosomal acid lipase (LAL). The respective contributions that our three cholesterol esterifying enzymes make to EC production, especially in disorders like CESD, are not well defined. The current studies represent a detailed exploration of our earlier findings in young male LAL-deficient mice also missing sterol O-acyltransferase 2 (SOAT2, also called ACAT2). Here we show that, even as they aged, male and female Lal-/-: Soat2- /- mice, compared to Lal-/-: Soat2+/+ littermates, had appreciably less hepatomegaly as well as a marked reduction in the level of sequestration of EC, in liver transaminase activities, and in hepatic mRNA expression levels for markers of inflammation. Loss of SOAT2 function also dramatically curtailed EC entrapment in the small intestine of the LAL-deficient mice. Together, these data imply that SOAT2 inhibition, if applied concurrently with enzyme replacement therapy for LAL deficiency, may blunt the re-esterification of newly released unesterified cholesterol thereby improving clinical outcomes.
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Affiliation(s)
- Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
| | - Jen-Chieh Chuang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
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16
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Sun X, Wang SC, Wei Y, Luo X, Jia Y, Li L, Gopal P, Zhu M, Nassour I, Chuang JC, Maples T, Celen C, Nguyen LH, Wu L, Fu S, Li W, Hui L, Tian F, Ji Y, Zhang S, Sorouri M, Hwang TH, Letzig L, James L, Wang Z, Yopp AC, Singal AG, Zhu H. Arid1a Has Context-Dependent Oncogenic and Tumor Suppressor Functions in Liver Cancer. Cancer Cell 2018; 33:151-152. [PMID: 29316428 PMCID: PMC5783571 DOI: 10.1016/j.ccell.2017.12.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Sun X, Wang SC, Wei Y, Luo X, Jia Y, Li L, Gopal P, Zhu M, Nassour I, Chuang JC, Maples T, Celen C, Nguyen LH, Wu L, Fu S, Li W, Hui L, Tian F, Ji Y, Zhang S, Sorouri M, Hwang TH, Letzig L, James L, Wang Z, Yopp AC, Singal AG, Zhu H. Arid1a Has Context-Dependent Oncogenic and Tumor Suppressor Functions in Liver Cancer. Cancer Cell 2017; 32:574-589.e6. [PMID: 29136504 PMCID: PMC5728182 DOI: 10.1016/j.ccell.2017.10.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 08/10/2017] [Accepted: 10/11/2017] [Indexed: 12/11/2022]
Abstract
ARID1A, an SWI/SNF chromatin-remodeling gene, is commonly mutated in cancer and hypothesized to be tumor suppressive. In some hepatocellular carcinoma patients, ARID1A was highly expressed in primary tumors but not in metastatic lesions, suggesting that ARID1A can be lost after initiation. Mice with liver-specific homozygous or heterozygous Arid1a loss were resistant to tumor initiation while ARID1A overexpression accelerated initiation. In contrast, homozygous or heterozygous Arid1a loss in established tumors accelerated progression and metastasis. Mechanistically, gain of Arid1a function promoted initiation by increasing CYP450-mediated oxidative stress, while loss of Arid1a within tumors decreased chromatin accessibility and reduced transcription of genes associated with migration, invasion, and metastasis. In summary, ARID1A has context-dependent tumor-suppressive and oncogenic roles in cancer.
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MESH Headings
- Animals
- Blotting, Western
- Carcinogenesis/genetics
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cell Line, Tumor
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Gene Expression Profiling/methods
- Gene Expression Regulation, Neoplastic
- Genes, Tumor Suppressor
- Humans
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Liver Neoplasms/pathology
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Neoplasm Metastasis
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Oncogenes/genetics
- RNA Interference
- Transcription Factors
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Affiliation(s)
- Xuxu Sun
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sam C Wang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yonglong Wei
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Luo
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yuemeng Jia
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lin Li
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Purva Gopal
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Min Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ibrahim Nassour
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen-Chieh Chuang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Thomas Maples
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Cemre Celen
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Liem H Nguyen
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Linwei Wu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Organ Transplant Center, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Shunjun Fu
- Organ Transplant Center, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Weiping Li
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lijian Hui
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Feng Tian
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yuan Ji
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shuyuan Zhang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mahsa Sorouri
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tae Hyun Hwang
- Lerner Research Institute, Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Lynda Letzig
- Clinical Pharmacology and Toxicology, Arkansas Children's Hospital and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Laura James
- Clinical Pharmacology and Toxicology, Arkansas Children's Hospital and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Zixi Wang
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adam C Yopp
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Amit G Singal
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hao Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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18
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Celen C, Chuang JC, Luo X, Nijem N, Walker AK, Chen F, Zhang S, Chung AS, Nguyen LH, Nassour I, Budhipramono A, Sun X, Bok LA, McEntagart M, Gevers EF, Birnbaum SG, Eisch AJ, Powell CM, Ge WP, Santen GW, Chahrour M, Zhu H. Arid1b haploinsufficient mice reveal neuropsychiatric phenotypes and reversible causes of growth impairment. eLife 2017; 6. [PMID: 28695822 PMCID: PMC5515576 DOI: 10.7554/elife.25730] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/24/2017] [Indexed: 12/17/2022] Open
Abstract
Sequencing studies have implicated haploinsufficiency of ARID1B, a SWI/SNF chromatin-remodeling subunit, in short stature (Yu et al., 2015), autism spectrum disorder (O'Roak et al., 2012), intellectual disability (Deciphering Developmental Disorders Study, 2015), and corpus callosum agenesis (Halgren et al., 2012). In addition, ARID1B is the most common cause of Coffin-Siris syndrome, a developmental delay syndrome characterized by some of the above abnormalities (Santen et al., 2012; Tsurusaki et al., 2012; Wieczorek et al., 2013). We generated Arid1b heterozygous mice, which showed social behavior impairment, altered vocalization, anxiety-like behavior, neuroanatomical abnormalities, and growth impairment. In the brain, Arid1b haploinsufficiency resulted in changes in the expression of SWI/SNF-regulated genes implicated in neuropsychiatric disorders. A focus on reversible mechanisms identified Insulin-like growth factor (IGF1) deficiency with inadequate compensation by Growth hormone-releasing hormone (GHRH) and Growth hormone (GH), underappreciated findings in ARID1B patients. Therapeutically, GH supplementation was able to correct growth retardation and muscle weakness. This model functionally validates the involvement of ARID1B in human disorders, and allows mechanistic dissection of neurodevelopmental diseases linked to chromatin-remodeling. DOI:http://dx.doi.org/10.7554/eLife.25730.001 DNA does not just float freely inside our cells. Instead, it is wound around proteins called histones and packaged tidily into a form called chromatin. This packaging allows genes to be switched on or off by making it easier or harder to access different stretches of the genetic code. A group of proteins called the SWI/SNF chromatin-remodeling complex are responsible for the packing and unpacking of DNA during development, dictating the fate of thousands of genes. Mutations that affect one component of this complex, a protein known ARID1B, are associated with a rare genetic condition called Coffin-Siris syndrome, and may also have a role to play in autism spectrum disorders and intellectual disability. However, there were previously no animal models that can be used to study this mutation in the laboratory. Celen, Chuang et al. have now genetically modified mice to remove one of their two copies of the gene that encodes the mouse equivalent of ARID1B. This change replicates the mutation that is most commonly seen in people with Coffin-Siris syndrome. Celen, Chuang et al. report that the mutant mice with just one working copy of the gene showed many features also seen in Coffin-Siris syndrome, including a smaller size and weaker muscles. The mutant mice also repeated certain behaviors, like grooming themselves, and showed unusual interactions with other mice. Further tests showed that the mutant mice had lower than expected levels of growth hormone in their blood. The mice were then treated with growth hormone supplements to find out if this could reverse any of their symptoms. Indeed, this treatment made the mice larger and stronger, but did not change their behavior. Some doctors are already treating people with Coffin-Siris syndrome with growth hormone, and these new findings suggest that this treatment counteracts defects caused directly by the mutation affecting ARID1B. Moreover, this mouse model will allow the role of ARID1B to be investigated further in the laboratory, and could be used as a tool to discover, develop and test new treatments for Coffin-Siris syndrome. DOI:http://dx.doi.org/10.7554/eLife.25730.002
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Affiliation(s)
- Cemre Celen
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jen-Chieh Chuang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Xin Luo
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Nadine Nijem
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.,Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, United States
| | - Angela K Walker
- Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Fei Chen
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Shuyuan Zhang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Andrew S Chung
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Liem H Nguyen
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ibrahim Nassour
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Albert Budhipramono
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Xuxu Sun
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Levinus A Bok
- Department of Pediatrics, Máxima Medical Center, Veldhoven, The Netherlands
| | - Meriel McEntagart
- Medical Genetics, St George's University Hospitals, NHS Foundation Trust, United Kingdom Caroline Brain, Endocrinology, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Evelien F Gevers
- William Harvey Research Institute, Barts and the London, Queen Mary University of London, London, United Kingdom
| | - Shari G Birnbaum
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Amelia J Eisch
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, and Mahoney Institute of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Craig M Powell
- Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Woo-Ping Ge
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Gijs We Santen
- Department of Clinical genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Maria Chahrour
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.,Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, United States
| | - Hao Zhu
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
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19
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Abstract
Every organ in the body is capable of synthesizing cholesterol de novo but at rates that vary with a constellation of factors. A significant proportion of the hydrogen atoms present in cholesterol that is synthesized in the body are derived from water. Thus, although water ordinarily makes up the bulk of body mass, the acute enrichment of the body water pool with a sufficiently large amount of tritiated water over a short interval of time (usually 1 h) yields measurable rates of incorporation of the labeled water into newly generated cholesterol and also fatty acids. Such data can provide a quantitative measure of how specific genetic, dietary, and pharmacological manipulations impact not just the rate of cholesterol synthesis in particular organs but also rates of whole-body cholesterol production and turnover.
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Affiliation(s)
- Adam M Lopez
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA
| | - Jen-Chieh Chuang
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA
| | - Stephen D Turley
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA.
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20
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Lopez AM, Chuang JC, Posey KS, Turley SD. 'Corrigenda to "Suppression of brain cholesterol synthesis in male Mecp2-deficient mice is age dependent and not accompanied by a concurrent change in the rate of fatty acid synthesis" [Brain Res. 1654 (2017) 77-84]'. Brain Res 2016; 1657:383. [PMID: 28017700 PMCID: PMC5568827 DOI: 10.1016/j.brainres.2016.12.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen-Chieh Chuang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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21
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Lopez AM, Chuang JC, Posey KS, Turley SD. Suppression of brain cholesterol synthesis in male Mecp2-deficient mice is age dependent and not accompanied by a concurrent change in the rate of fatty acid synthesis. Brain Res 2016; 1654:77-84. [PMID: 27789278 DOI: 10.1016/j.brainres.2016.10.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/13/2016] [Accepted: 10/21/2016] [Indexed: 12/29/2022]
Abstract
Mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2) are the principal cause of Rett syndrome, a progressive neurodevelopmental disorder afflicting 1 in 10,000 to 15,000 females. Studies using hemizygous Mecp2 mouse models have revealed disruptions to some aspects of their lipid metabolism including a partial suppression of cholesterol synthesis in the brains of mature Mecp2 mutants. The present studies investigated whether this suppression is evident from early neonatal life, or becomes manifest at a later stage of development. We measured the rate of cholesterol synthesis, in vivo, in the brains of male Mecp2-/y and their Mecp2+/y littermates at 7, 14, 21, 28, 42 and 56 days of age. Brain weight was consistently lower in the Mecp2-/y mice than in their Mecp2+/y controls except at 7 days of age. In the 7- and 14-day-old mice there was no genotypic difference in the rate of brain cholesterol synthesis but, from 21 days and later, it was always marginally lower in the Mecp2-/y mice than in age-matched Mecp2+/y littermates. At no age was a genotypic difference detected in either the rate of fatty acid synthesis or cholesterol concentration in the brain. Cholesterol synthesis rates in the liver and lungs of 56-day-old Mecp2-/y mice were normal. The onset of lower rates of brain cholesterol synthesis at about the time closure of the blood brain barrier purportedly occurs might signify a disruption to mechanism(s) that dictate intracellular levels of cholesterol metabolites including oxysterols known to exert a regulatory influence on the cholesterol biosynthetic pathway.
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Affiliation(s)
- Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Jen-Chieh Chuang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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22
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Sun X, Wang S, Maples T, Li L, Nguyen L, Chuang JC, Sorouri M, Zhang S, Wu L, Celen C, Zhu H. Abstract PR02: The SWI/SNF component Arid1a regulates regenerative capacity and carcinogenesis in a dose-dependent fashion. Mol Cancer Res 2016. [DOI: 10.1158/1557-3125.devbiolca15-pr02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
It is unclear if regenerative capacity can be dissociated from cancer risk, a question that is highly relevant for liver carcinogenesis. Frequent SWI/SNF and Arid1a loss-of-function mutations suggest tumor suppressive roles, but the functional impact of these mutations in tissue homeostasis and cancer is unclear. Mice without Arid1a possessed improved healing abilities after an array of injuries. After liver resection, chemical hepatocyte injury, and toxic bile duct injury, Arid1a deficient livers exhibited increased regeneration, reduced tissue damage, and improved organ function. Moreover, global homozygous Arid1a loss potentiated soft tissue healing after ear hole punch and hematopoietic recovery after irradiation. The chromatin state as reprogrammed by Arid1a loss restricted access to promoters by lineage-specific transcription factors that ordinarily suppress cell cycle reentry, thus increasing regeneration after injury. Intriguingly, the homozygous Arid1a deficient state protected mice from chemical injury induced hepatocellular carcinoma (HCC) and extended survival in a MYC-driven hepatoblastoma model. Since Arid1a mutations are most frequently heterozygous in human HCC genome studies, we examined the haploinsufficient state in these mouse models and observed accelerated carcinogenesis and metastasis. Transcriptome analysis identified dysregulated differentiation, proliferation, and metastasis programs. These models show that full deletion of Arid1a can enhance mammalian regeneration without increasing cancer risk, but that Arid1a’s tumor suppressor functions are highly sensitive to dose.
This abstract is also presented as Poster A16.
Citation Format: Xuxu Sun, Sam Wang, Thomas Maples, Lin Li, Liem Nguyen, Jen-Chieh Chuang, Mahsa Sorouri, Shuyuan Zhang, Linwei Wu, Cemre Celen, Hao Zhu. The SWI/SNF component Arid1a regulates regenerative capacity and carcinogenesis in a dose-dependent fashion. [abstract]. In: Proceedings of the AACR Special Conference: Developmental Biology and Cancer; Nov 30-Dec 3, 2015; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(4_Suppl):Abstract nr PR02.
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Affiliation(s)
- Xuxu Sun
- Children’s Research Institute at UTSW, Dallas, TX
| | - Sam Wang
- Children’s Research Institute at UTSW, Dallas, TX
| | | | - Lin Li
- Children’s Research Institute at UTSW, Dallas, TX
| | - Liem Nguyen
- Children’s Research Institute at UTSW, Dallas, TX
| | | | | | | | - Linwei Wu
- Children’s Research Institute at UTSW, Dallas, TX
| | - Cemre Celen
- Children’s Research Institute at UTSW, Dallas, TX
| | - Hao Zhu
- Children’s Research Institute at UTSW, Dallas, TX
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23
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Sun X, Chuang JC, Kanchwala M, Wu L, Celen C, Li L, Liang H, Zhang S, Maples T, Nguyen LH, Wang SC, Signer RAJ, Sorouri M, Nassour I, Liu X, Xu J, Wu M, Zhao Y, Kuo YC, Wang Z, Xing C, Zhu H. Suppression of the SWI/SNF Component Arid1a Promotes Mammalian Regeneration. Cell Stem Cell 2016; 18:456-66. [PMID: 27044474 DOI: 10.1016/j.stem.2016.03.001] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 01/07/2016] [Accepted: 03/02/2016] [Indexed: 01/10/2023]
Abstract
Mammals have partially lost the extensive regenerative capabilities of some vertebrates, possibly as a result of chromatin-remodeling mechanisms that enforce terminal differentiation. Here, we show that deleting the SWI/SNF component Arid1a substantially improves mammalian regeneration. Arid1a expression is suppressed in regenerating tissues, and genetic deletion of Arid1a increases tissue repair following an array of injuries. Arid1a deficiency in the liver increases proliferation, reduces tissue damage and fibrosis, and improves organ function following surgical resection and chemical injuries. Hepatocyte-specific deletion is also sufficient to increase proliferation and regeneration without excessive overgrowth, and global Arid1a disruption potentiates soft tissue healing in the ear. We show that Arid1a loss reprograms chromatin to restrict promoter access by transcription factors such as C/ebpα, which enforces differentiation, and E2F4, which suppresses cell-cycle re-entry. Thus, epigenetic reprogramming mediated by deletion of a single gene improves mammalian regeneration and suggests strategies to promote tissue repair after injury.
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Affiliation(s)
- Xuxu Sun
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen-Chieh Chuang
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mohammed Kanchwala
- Bioinformatics Core, Eugene McDermott Center for Human Growth & Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Linwei Wu
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Organ Transplant Center, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Cemre Celen
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lin Li
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hanquan Liang
- Bioinformatics Core, Eugene McDermott Center for Human Growth & Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shuyuan Zhang
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Thomas Maples
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Liem H Nguyen
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Sam C Wang
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Robert A J Signer
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mahsa Sorouri
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ibrahim Nassour
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Liu
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jian Xu
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Meng Wu
- Mindich Child Health and Development Institute and Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yong Zhao
- Mindich Child Health and Development Institute and Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yi-Chun Kuo
- Departments of Pharmacology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zhong Wang
- Department of Cardiac Surgery, Cardiovascular Research Center, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
| | - Chao Xing
- Bioinformatics Core, Eugene McDermott Center for Human Growth & Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hao Zhu
- Departments of Pediatrics and Internal Medicine, Children's Research Institute, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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24
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Lopez AM, Chuang JC, Posey KS, Ohshiro T, Tomoda H, Rudel LL, Turley SD. PRD125, a potent and selective inhibitor of sterol O-acyltransferase 2 markedly reduces hepatic cholesteryl ester accumulation and improves liver function in lysosomal acid lipase-deficient mice. J Pharmacol Exp Ther 2015; 355:159-67. [PMID: 26283692 PMCID: PMC4613965 DOI: 10.1124/jpet.115.227207] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/14/2015] [Indexed: 11/22/2022] Open
Abstract
In most organs, the bulk of cholesterol is unesterified, although nearly all possess a varying capability of esterifying cholesterol through the action of either sterol O-acyltransferase (SOAT) 1 or, in the case of hepatocytes and enterocytes, SOAT2. Esterified cholesterol (EC) carried in plasma lipoproteins is hydrolyzed by lysosomal acid lipase (LAL) when they are cleared from the circulation. Loss-of-function mutations in LIPA, the gene that encodes LAL, result in Wolman disease or cholesteryl ester storage disease (CESD). Hepatomegaly and a massive increase in tissue EC levels are hallmark features of both disorders. While these conditions can be corrected with enzyme replacement therapy, the question arose as to whether pharmacological inhibition of SOAT2 might reduce tissue EC accretion in CESD. When weaned at 21 days, Lal(-/-) mice, of either gender, had a whole liver cholesterol content that was 12- to 13-fold more than that of matching Lal(+/+) littermates (23 versus 1.8 mg, respectively). In Lal(-/-) males given the selective SOAT2 inhibitor PRD125 1,11-O-o-methylbenzylidene-7-O-p-cyanobenzoyl-1,7,11-trideacetylpyripyropene A in their diet (∼10 mg/day per kg body weight) from 21 to 53 days, whole liver cholesterol content was 48.6 versus 153.7 mg in untreated 53-day-old Lal(-/-) mice. This difference reflected a 59% reduction in hepatic EC concentration (mg/g), combined with a 28% fall in liver mass. The treated mice also showed a 63% reduction in plasma alanine aminotransferase activity, in parallel with decisive falls in hepatic mRNA expression levels for multiple proteins that reflect macrophage presence and inflammation. These data implicate SOAT2 as a potential target in CESD management.
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Affiliation(s)
- Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Jen-Chieh Chuang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Taichi Ohshiro
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Hiroshi Tomoda
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Lawrence L Rudel
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (A.M.L., J-C.C., K.S.P., S.D.T.); Graduate School of Pharmaceutical Science, Kitasato University, Tokyo, Japan (T.O., H.T.); and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (T.O., L.L.R.)
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25
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Jones RD, Lopez AM, Tong EY, Posey KS, Chuang JC, Repa JJ, Turley SD. Impact of physiological levels of chenodeoxycholic acid supplementation on intestinal and hepatic bile acid and cholesterol metabolism in Cyp7a1-deficient mice. Steroids 2015; 93:87-95. [PMID: 25447797 PMCID: PMC4297738 DOI: 10.1016/j.steroids.2014.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 11/07/2014] [Indexed: 01/07/2023]
Abstract
Mice deficient in cholesterol 7α-hydroxylase (Cyp7a1) have a diminished bile acid pool (BAP) and therefore represent a useful model for investigating the metabolic effects of restoring the pool with a specific BA. Previously we carried out such studies in Cyp7a1(-/-) mice fed physiological levels of cholic acid (CA) and achieved BAP restoration, along with an increased CA enrichment, at a dietary level of just 0.03% (w/w). Here we demonstrate that in Cyp7a1(-/-) mice fed chenodeoxycholic acid (CDCA) at a level of 0.06% (w/w), the BAP was restored to normal size and became substantially enriched with muricholic acid (MCA) (>70%), leaving the combined contribution of CA and CDCA to be <15%. This resulted in a partial to complete reversal of the main changes in cholesterol and BA metabolism associated with Cyp7a1 deficiency such as an elevated rate of intestinal sterol synthesis, an enhanced level of mRNA for Cyp8b1 in the liver, and depressed mRNA levels for Ibabp, Shp and Fgf15 in the distal small intestine. When Cyp7a1(-/-) and matching Cyp7a1(+/+) mice were fed a diet with added cholesterol (0.2%) (w/w), either alone, or also containing CDCA (0.06%) (w/w) or CA (0.03%) (w/w) for 18days, the hepatic total cholesterol concentrations (mg/g) in the Cyp7a1(-/-) mice were 26.9±3.7, 16.4±0.9 and 47.6±1.9, respectively, vs. 4.9±0.4, 5.0±0.7 and 6.4±1.9, respectively in the corresponding Cyp7a1(+/+) controls. These data affirm the importance of using moderate levels of dietary BA supplementation to elicit changes in hepatic cholesterol metabolism through shifts in BAP size and composition.
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Affiliation(s)
- Ryan D Jones
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Ernest Y Tong
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Jen-Chieh Chuang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Joyce J Repa
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
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Mundy DI, Lopez AM, Posey KS, Chuang JC, Ramirez CM, Scherer PE, Turley SD. Impact of the loss of caveolin-1 on lung mass and cholesterol metabolism in mice with and without the lysosomal cholesterol transporter, Niemann-Pick type C1. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:995-1002. [PMID: 24747682 DOI: 10.1016/j.bbalip.2014.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 04/08/2014] [Accepted: 04/11/2014] [Indexed: 11/17/2022]
Abstract
Caveolin-1 (Cav-1) is a major structural protein in caveolae in the plasma membranes of many cell types, particularly endothelial cells and adipocytes. Loss of Cav-1 function has been implicated in multiple diseases affecting the cardiopulmonary and central nervous systems, as well as in specific aspects of sterol and lipid metabolism in the liver and intestine. Lungs contain an exceptionally high level of Cav-1. Parameters of cholesterol metabolism in the lung were measured, initially in Cav-1-deficient mice (Cav-1(-/-)), and subsequently in Cav-1(-/-) mice that also lacked the lysosomal cholesterol transporter Niemann-Pick C1 (Npc1) (Cav-1(-/-):Npc1(-/-)). In 50-day-old Cav-1(-/-) mice fed a low- or high-cholesterol chow diet, the total cholesterol concentration (mg/g) in the lungs was marginally lower than in the Cav-1(+/+) controls, but due to an expansion in their lung mass exceeding 30%, whole-lung cholesterol content (mg/organ) was moderately elevated. Lung mass (g) in the Cav-1(-/-):Npc1(-/-) mice (0.356±0.022) markedly exceeded that in their Cav-1(+/+):Npc1(+/+) controls (0.137±0.009), as well as in their Cav-1(-/-):Npc1(+/+) (0.191±0.013) and Cav-1(+/+):Npc1(-/-) (0.213±0.022) littermates. The corresponding lung total cholesterol contents (mg/organ) in mice of these genotypes were 6.74±0.17, 0.71±0.05, 0.96±0.05 and 3.12±0.43, respectively, with the extra cholesterol in the Cav-1(-/-):Npc1(-/-) and Cav-1(+/+):Npc1(-/-) mice being nearly all unesterified (UC). The exacerbation of the Npc1 lung phenotype and increase in the UC level in the Cav-1(-/-):Npc1(-/-) mice imply a regulatory role of Cav-1 in pulmonary cholesterol metabolism when lysosomal sterol transport is disrupted.
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Affiliation(s)
- Dorothy I Mundy
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Jen-Chieh Chuang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Charina M Ramirez
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Philipp E Scherer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA.
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Chuang JC, Valasek MA, Lopez AM, Posey KS, Repa JJ, Turley SD. Sustained and selective suppression of intestinal cholesterol synthesis by Ro 48-8071, an inhibitor of 2,3-oxidosqualene:lanosterol cyclase, in the BALB/c mouse. Biochem Pharmacol 2014; 88:351-63. [PMID: 24486573 DOI: 10.1016/j.bcp.2014.01.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 01/11/2023]
Abstract
The small intestine plays a fundamentally important role in regulating whole body cholesterol balance and plasma lipoprotein composition. This is articulated through the interplay of a constellation of genes that ultimately determines the net amount of chylomicron cholesterol delivered to the liver. Major advances in our insights into regulation of the cholesterol absorption pathway have been made using genetically manipulated mouse models and agents such as ezetimibe. One unresolved question is how a sustained pharmacological inhibition of intestinal cholesterol synthesis in vivo may affect cholesterol handling by the absorptive cells. Here we show that the lanosterol cyclase inhibitor, Ro 48-8071, when fed to BALB/c mice in a chow diet (20 mg/day/kg body weight), leads to a rapid and sustained inhibition (>50%) of cholesterol synthesis in the whole small intestine. Sterol synthesis was also reduced in the large intestine and stomach. In contrast, hepatic cholesterol synthesis, while markedly suppressed initially, rebounded to higher than baseline rates within 7 days. Whole body cholesterol synthesis, fractional cholesterol absorption, and fecal neutral and acidic sterol excretion were not consistently changed with Ro 48-8071 treatment. There were no discernible effects of this agent on intestinal histology as determined by H&E staining and the level of Ki67, an index of proliferation. The mRNA expression for multiple genes involved in intestinal cholesterol regulation including NPC1L1 was mostly unchanged although there was a marked rise in the mRNA level for the PXR target genes CYP3A11 and CES2A.
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Affiliation(s)
- Jen-Chieh Chuang
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Mark A Valasek
- Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Adam M Lopez
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Kenneth S Posey
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Joyce J Repa
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States; Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Stephen D Turley
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
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Mani BK, Chuang JC, Kjalarsdottir L, Sakata I, Walker AK, Kuperman A, Osborne-Lawrence S, Repa JJ, Zigman JM. Role of calcium and EPAC in norepinephrine-induced ghrelin secretion. Endocrinology 2014; 155:98-107. [PMID: 24189139 PMCID: PMC3868802 DOI: 10.1210/en.2013-1691] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin is an orexigenic hormone secreted principally from a distinct population of gastric endocrine cells. Molecular mechanisms regulating ghrelin secretion are mostly unknown. Recently, norepinephrine (NE) was shown to enhance ghrelin release by binding to β1-adrenergic receptors on ghrelin cells. Here, we use an immortalized stomach-derived ghrelin cell line to further characterize the intracellular signaling pathways involved in NE-induced ghrelin secretion, with a focus on the roles of Ca(2+) and cAMP. Several voltage-gated Ca(2+) channel (VGCC) family members were found by quantitative PCR to be expressed by ghrelin cells. Nifedipine, a selective L-type VGCC blocker, suppressed both basal and NE-stimulated ghrelin secretion. NE induced elevation of cytosolic Ca(2+) levels both in the presence and absence of extracellular Ca(2+). Ca(2+)-sensing synaptotagmins Syt7 and Syt9 were also highly expressed in ghrelin cell lines, suggesting that they too help mediate ghrelin secretion. Raising cAMP with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine also stimulated ghrelin secretion, although such a cAMP-mediated effect likely does not involve protein kinase A, given the absence of a modulatory response to a highly selective protein kinase A inhibitor. However, pharmacological inhibition of another target of cAMP, exchange protein-activated by cAMP (EPAC), did attenuate both basal and NE-induced ghrelin secretion, whereas an EPAC agonist enhanced basal ghrelin secretion. We conclude that constitutive ghrelin secretion is primarily regulated by Ca(2+) influx through L-type VGCCs and that NE stimulates ghrelin secretion predominantly through release of intracellular Ca(2+). Furthermore, cAMP and its downstream activation of EPAC are required for the normal ghrelin secretory response to NE.
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Affiliation(s)
- Bharath K Mani
- Division of Endocrinology and Metabolism (B.K.M., J.-C.C., I.S., A.K.W., A.K., S.O.-L., J.M.Z.), Department of Internal Medicine; Division of Hypothalamic research (B.K.M., J.-C.C., L.K., I.S., A.K.W., A.K., S.O.-L., J.J.R., J.M.Z.), Department of Internal Medicine; and Departments of Psychiatry (B.K.M., J.-C.C., I.S., A.K.W., A.K., S.O.-L., J.M.Z.) and Physiology (L.K., J.J.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Wang Q, Liu C, Uchida A, Chuang JC, Walker A, Liu T, Osborne-Lawrence S, Mason BL, Mosher C, Berglund ED, Elmquist JK, Zigman JM. Arcuate AgRP neurons mediate orexigenic and glucoregulatory actions of ghrelin. Mol Metab 2013; 3:64-72. [PMID: 24567905 PMCID: PMC3929914 DOI: 10.1016/j.molmet.2013.10.001] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/08/2013] [Accepted: 10/08/2013] [Indexed: 12/21/2022] Open
Abstract
The hormone ghrelin stimulates eating and helps maintain blood glucose upon caloric restriction. While previous studies have demonstrated that hypothalamic arcuate AgRP neurons are targets of ghrelin, the overall relevance of ghrelin signaling within intact AgRP neurons is unclear. Here, we tested the functional significance of ghrelin action on AgRP neurons using a new, tamoxifen-inducible AgRP-CreERT2 transgenic mouse model that allows spatiotemporally-controlled re-expression of physiological levels of ghrelin receptors (GHSRs) specifically in AgRP neurons of adult GHSR-null mice that otherwise lack GHSR expression. AgRP neuron-selective GHSR re-expression partially restored the orexigenic response to administered ghrelin and fully restored the lowered blood glucose levels observed upon caloric restriction. The normalizing glucoregulatory effect of AgRP neuron-selective GHSR expression was linked to glucagon rises and hepatic gluconeogenesis induction. Thus, our data indicate that GHSR-containing AgRP neurons are not solely responsible for ghrelin's orexigenic effects but are sufficient to mediate ghrelin's effects on glycemia.
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Key Words
- ARC, arcuate nucleus
- AgRP
- AgRP, Agouti-related peptide
- BAC, bacterial artificial chromosome
- Blood glucose homeostasis
- CNS, central nervous system
- DG, dentate gyrus
- DVC, dorsal vagal complex
- Food intake
- Foxo1, Forkhead box protein O1
- G6p, glucose-6 phosphatase
- GABA, gamma-aminobutyric acid
- GHRH, Growth-hormone-releasing hormone
- GHSR, growth hormone secretagogue receptor, ghrelin receptor
- GOAT, ghrelin O-acyltransferase
- Ghrelin
- Ghrelin receptor
- Hnf4α, hepatocyte nuclear factor 4α
- NAc, nucleus accumbens
- NPY, neuropeptide Y
- POMC, pro-opiomelanocortin
- Pcx, pyruvate carboxylase
- Pepck, phosphoenolpyruvate carboxykinase
- Phox2b, paired-like homeobox 2b
- VGAT, vesicular GABA transporter
- VTA, ventral tegmental area
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Affiliation(s)
- Qian Wang
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chen Liu
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Aki Uchida
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jen-Chieh Chuang
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Angela Walker
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tiemin Liu
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Brittany L Mason
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Christina Mosher
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric D Berglund
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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Chin M, Lee CYI, Chuang JC, Bumeister R, Wigley WC, Sonis ST, Ward KW, Meyer C. Bardoxolone methyl analogs RTA 405 and dh404 are well tolerated and exhibit efficacy in rodent models of Type 2 diabetes and obesity. Am J Physiol Renal Physiol 2013; 304:F1438-46. [PMID: 23594825 DOI: 10.1152/ajprenal.00387.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bardoxolone methyl and related triterpenoids are well tolerated and efficacious in numerous animal models potentially relevant to patients with Type 2 diabetes and chronic kidney disease. These agents enhance glucose control and regulate lipid accumulation in rodent models of diabetes and obesity, and improve renal function, reduce inflammation, and prevent structural injury in models of renal disease. However, a recent study in Zucker diabetic fatty (ZDF) rats noted poor tolerability with the bardoxolone methyl analog RTA 405 within 1 mo after treatment initiation, although this study was confounded in part by the use of an impure RTA 405 batch. To investigate these discordant observations, the present studies were conducted to further characterize triterpenoids in rodent models of diabetes and obesity. A follow-up study was conducted in ZDF rats with two related triterpenoids (RTA 405 and dh404) for 1.5 mo. Consistent with previous rodent experience, and in contrast to the more recent ZDF report, ZDF rats administered RTA 405 or dh404 exhibited no adverse clinical signs, had laboratory values similar to controls, and exhibited no evidence of adverse liver or kidney histopathology. Additionally, RTA 405 was well tolerated in streptozotocin-induced Type 1 diabetic rats and high-fat-diet-induced obese mice. The present results are consistent with the overall published body of data obtained with triterpenoids and provide further evidence that these molecules are well tolerated without adverse effects on hepatobiliary or renal function in rodent models of diabetes and obesity.
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Kumar J, Chuang JC, Na ES, Kuperman A, Gillman AG, Mukherjee S, Zigman JM, McClung CA, Lutter M. Differential effects of chronic social stress and fluoxetine on meal patterns in mice. Appetite 2013; 64:81-8. [PMID: 23318656 DOI: 10.1016/j.appet.2012.12.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 11/09/2012] [Accepted: 12/14/2012] [Indexed: 01/03/2023]
Abstract
Both chronic stress and antidepressant medications have been associated with changes in body weight. In the current study, we investigate mechanisms by which stress and antidepressants interact to affect meal patterns. A group of mice was subjected to the chronic social defeat stress model of major depression followed by fluoxetine treatment and was subsequently analyzed for food intake using metabolic cages. We report that chronic social defeat stress increases food intake by specifically increasing meal size, an effect that is reversed by fluoxetine treatment. In an attempt to gain mechanistic insight into changes in meal patterning induced by stress and fluoxetine, fasting serum samples were collected every 4h over a 24-h period, and acyl-ghrelin, leptin, and corticosterone levels were measured. Chronic stress induces a peak in acyl-ghrelin levels just prior to the onset of the dark phase, which is shifted in mice treated with fluoxetine. Taken together, these results indicate that stress increases food intake by decreasing satiation, and that fluoxetine can reverse stress-induced changes in meal patterns.
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Affiliation(s)
- Jaswinder Kumar
- Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9070, USA.
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Scott MM, Perello M, Chuang JC, Sakata I, Gautron L, Lee CE, Lauzon D, Elmquist JK, Zigman JM. Hindbrain ghrelin receptor signaling is sufficient to maintain fasting glucose. PLoS One 2012; 7:e44089. [PMID: 22952883 PMCID: PMC3432098 DOI: 10.1371/journal.pone.0044089] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/01/2012] [Indexed: 11/19/2022] Open
Abstract
The neuronal coordination of metabolic homeostasis requires the integration of hormonal signals with multiple interrelated central neuronal circuits to produce appropriate levels of food intake, energy expenditure and fuel availability. Ghrelin, a peripherally produced peptide hormone, circulates at high concentrations during nutrient scarcity. Ghrelin promotes food intake, an action lost in ghrelin receptor null mice and also helps maintain fasting blood glucose levels, ensuring an adequate supply of nutrients to the central nervous system. To better understand mechanisms of ghrelin action, we have examined the roles of ghrelin receptor (GHSR) expression in the mouse hindbrain. Notably, selective hindbrain ghrelin receptor expression was not sufficient to restore ghrelin-stimulated food intake. In contrast, the lowered fasting blood glucose levels observed in ghrelin receptor-deficient mice were returned to wild-type levels by selective re-expression of the ghrelin receptor in the hindbrain. Our results demonstrate the distributed nature of the neurons mediating ghrelin action.
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Affiliation(s)
- Michael M. Scott
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Mario Perello
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Jen-Chieh Chuang
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Ichiro Sakata
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Laurent Gautron
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Charlotte E. Lee
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Danielle Lauzon
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Joel K. Elmquist
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Department of Psychiatry, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- * E-mail: (JKE); (JMZ)
| | - Jeffrey M. Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Department of Psychiatry, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- * E-mail: (JKE); (JMZ)
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Sakata I, Park WM, Walker AK, Piper PK, Chuang JC, Osborne-Lawrence S, Zigman JM. Glucose-mediated control of ghrelin release from primary cultures of gastric mucosal cells. Am J Physiol Endocrinol Metab 2012; 302:E1300-10. [PMID: 22414807 PMCID: PMC3361986 DOI: 10.1152/ajpendo.00041.2012] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The peptide hormone ghrelin is released from a distinct group of gastrointestinal cells in response to caloric restriction, whereas its levels fall after eating. The mechanisms by which ghrelin secretion is regulated remain largely unknown. Here, we have used primary cultures of mouse gastric mucosal cells to investigate ghrelin secretion, with an emphasis on the role of glucose. Ghrelin secretion from these cells upon exposure to different d-glucose concentrations, the glucose antimetabolite 2-deoxy-d-glucose, and other potential secretagogues was assessed. The expression profile of proteins involved in glucose transport, metabolism, and utilization within highly enriched pools of mouse ghrelin cells and within cultured ghrelinoma cells was also determined. Ghrelin release negatively correlated with d-glucose concentration. Insulin blocked ghrelin release, but only in a low d-glucose environment. 2-Deoxy-d-glucose prevented the inhibitory effect of high d-glucose exposure on ghrelin release. mRNAs encoding several facilitative glucose transporters, hexokinases, the ATP-sensitive potassium channel subunit Kir6.2, and sulfonylurea type 1 receptor were expressed highly within ghrelin cells, although neither tolbutamide nor diazoxide exerted direct effects on ghrelin secretion. These findings suggest that direct exposure of ghrelin cells to low ambient d-glucose stimulates ghrelin release, whereas high d-glucose and glucose metabolism within ghrelin cells block ghrelin release. Also, low d-glucose sensitizes ghrelin cells to insulin. Various glucose transporters, channels, and enzymes that mediate glucose responsiveness in other cell types may contribute to the ghrelin cell machinery involved in regulating ghrelin secretion under these different glucose environments, although their exact roles in ghrelin release remain uncertain.
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Affiliation(s)
- Ichiro Sakata
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9077, USA
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Perello M, Scott MM, Sakata I, Lee CE, Chuang JC, Osborne-Lawrence S, Rovinsky SA, Elmquist JK, Zigman JM. Functional implications of limited leptin receptor and ghrelin receptor coexpression in the brain. J Comp Neurol 2012; 520:281-94. [PMID: 21674492 DOI: 10.1002/cne.22690] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The hormones leptin and ghrelin act in apposition to one another in the regulation of body weight homeostasis. Interestingly, both leptin receptor expression and ghrelin receptor expression have been observed within many of the same nuclei of the central nervous system (CNS), suggesting that these hormones may act on a common population of neurons to produce changes in food intake and energy expenditure. In the present study we explored the extent of this putative direct leptin and ghrelin interaction in the CNS and addressed the question of whether a loss of ghrelin signaling would affect sensitivity to leptin. Using histological mapping of leptin receptor and ghrelin receptor expression, we found that cells containing both leptin receptors and ghrelin receptors are mainly located in the medial part of the hypothalamic arcuate nucleus. In contrast, coexpression was much less extensive elsewhere in the brain. To assess the functional consequences of this observed receptor distribution, we explored the effect of ghrelin receptor deletion on leptin sensitivity. In particular, the responses of ad libitum-fed, diet-induced obese and fasted mice to the anorectic actions of leptin were examined. Surprisingly, we found that deletion of the ghrelin receptor did not affect the sensitivity to exogenously administrated leptin. Thus, we conclude that ghrelin and leptin act largely on distinct neuronal populations and that ghrelin receptor deficiency does not affect sensitivity to the anorexigenic and body weight-lowering actions of leptin.
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Affiliation(s)
- Mario Perello
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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35
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Berglund ED, Vianna CR, Donato J, Kim MH, Chuang JC, Lee CE, Lauzon DA, Lin P, Brule LJ, Scott MM, Coppari R, Elmquist JK. Direct leptin action on POMC neurons regulates glucose homeostasis and hepatic insulin sensitivity in mice. J Clin Invest 2012; 122:1000-9. [PMID: 22326958 DOI: 10.1172/jci59816] [Citation(s) in RCA: 244] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 01/04/2012] [Indexed: 01/01/2023] Open
Abstract
Leptin action on its receptor (LEPR) stimulates energy expenditure and reduces food intake, thereby lowering body weight. One leptin-sensitive target cell mediating these effects on energy balance is the proopiomelano-cortin (POMC) neuron. Recent evidence suggests that the action of leptin on POMC neurons regulates glucose homeostasis independently of its effects on energy balance. Here, we have dissected the physiological impact of direct leptin action on POMC neurons using a mouse model in which endogenous LEPR expression was prevented by a LoxP-flanked transcription blocker (loxTB), but could be reactivated by Cre recombinase. Mice homozygous for the Lepr(loxTB) allele were obese and exhibited defects characteristic of LEPR deficiency. Reexpression of LEPR only in POMC neurons in the arcuate nucleus of the hypothalamus did not reduce food intake, but partially normalized energy expenditure and modestly reduced body weight. Despite the moderate effects on energy balance and independent of changes in body weight, restoring LEPR in POMC neurons normalized blood glucose and ameliorated hepatic insulin resistance, hyperglucagonemia, and dyslipidemia. Collectively, these results demonstrate that direct leptin action on POMC neurons does not reduce food intake, but is sufficient to normalize glucose and glucagon levels in mice otherwise lacking LEPR.
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Affiliation(s)
- Eric D Berglund
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, Texas 75390-9051, USA
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36
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Chuang JC, Sakata I, Kohno D, Perello M, Osborne-Lawrence S, Repa JJ, Zigman JM. Ghrelin directly stimulates glucagon secretion from pancreatic alpha-cells. Mol Endocrinol 2011; 25:1600-11. [PMID: 21719535 DOI: 10.1210/me.2011-1001] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Previous work has demonstrated that the peptide hormone ghrelin raises blood glucose. Such has been attributed to ghrelin's ability to enhance GH secretion, restrict insulin release, and/or reduce insulin sensitivity. Ghrelin's reported effects on glucagon have been inconsistent. Here, both animal- and cell-based systems were used to determine the role of glucagon in mediating ghrelin's effects on blood glucose. The tissue and cell distribution of ghrelin receptors (GHSR) was evaluated by quantitative PCR and histochemistry. Plasma glucagon levels were determined following acute acyl-ghrelin injections and in pharmacological and/or transgenic mouse models of ghrelin overexpression and GHSR deletion. Isolated mouse islets and the α-cell lines αTC1 and InR1G9 were used to evaluate ghrelin's effects on glucagon secretion and the role of calcium and ERK in this activity. GHSR mRNA was abundantly expressed in mouse islets and colocalized with glucagon in α-cells. Elevation of acyl-ghrelin acutely (after sc administration, such that physiologically relevant plasma ghrelin levels were achieved) and chronically (by slow-releasing osmotic pumps and as observed in transgenic mice harboring ghrelinomas) led to higher plasma glucagon and increased blood glucose. Conversely, genetic GHSR deletion was associated with lower plasma glucagon and reduced fasting blood glucose. Acyl-ghrelin increased glucagon secretion in a dose-dependent manner from mouse islets and α-cell lines, in a manner requiring elevation of intracellular calcium and phosphorylation of ERK. Our study shows that ghrelin's regulation of blood glucose involves direct stimulation of glucagon secretion from α-cells and introduces the ghrelin-glucagon axis as an important mechanism controlling glycemia under fasting conditions.
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Affiliation(s)
- Jen-Chieh Chuang
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
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Chuang JC, Perello M, Sakata I, Osborne-Lawrence S, Savitt JM, Lutter M, Zigman JM. Ghrelin mediates stress-induced food-reward behavior in mice. J Clin Invest 2011; 121:2684-92. [PMID: 21701068 DOI: 10.1172/jci57660] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 04/13/2011] [Indexed: 11/17/2022] Open
Abstract
The popular media and personal anecdotes are rich with examples of stress-induced eating of calorically dense "comfort foods." Such behavioral reactions likely contribute to the increased prevalence of obesity in humans experiencing chronic stress or atypical depression. However, the molecular substrates and neurocircuits controlling the complex behaviors responsible for stress-based eating remain mostly unknown, and few animal models have been described for probing the mechanisms orchestrating this response. Here, we describe a system in which food-reward behavior, assessed using a conditioned place preference (CPP) task, is monitored in mice after exposure to chronic social defeat stress (CSDS), a model of prolonged psychosocial stress, featuring aspects of major depression and posttraumatic stress disorder. Under this regime, CSDS increased both CPP for and intake of high-fat diet, and stress-induced food-reward behavior was dependent on signaling by the peptide hormone ghrelin. Also, signaling specifically in catecholaminergic neurons mediated not only ghrelin's orexigenic, antidepressant-like, and food-reward behavioral effects, but also was sufficient to mediate stress-induced food-reward behavior. Thus, this mouse model has allowed us to ascribe a role for ghrelin-engaged catecholaminergic neurons in stress-induced eating.
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Affiliation(s)
- Jen-Chieh Chuang
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
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38
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Xu Y, Berglund ED, Sohn JW, Holland WL, Chuang JC, Fukuda M, Rossi J, Williams KW, Jones JE, Zigman JM, Lowell BB, Scherer PE, Elmquist JK. 5-HT2CRs expressed by pro-opiomelanocortin neurons regulate insulin sensitivity in liver. Nat Neurosci 2010; 13:1457-9. [PMID: 21037584 PMCID: PMC3059249 DOI: 10.1038/nn.2664] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 09/15/2010] [Indexed: 11/09/2022]
Abstract
Mice lacking 5-HT 2C receptors (5-HT(2C)Rs) displayed hepatic insulin resistance, a phenotype normalized by re-expression of 5-HT(2C)Rs only in pro-opiomelanocortin (POMC) neurons. 5-HT(2C)R deficiency also abolished the anti-diabetic effects of meta-chlorophenylpiperazine (a 5-HT(2C)R agonist); these effects were restored when 5-HT(2C)Rs were re-expressed in POMC neurons. Our findings indicate that 5-HT(2C)Rs expressed by POMC neurons are physiologically relevant regulators of insulin sensitivity and glucose homeostasis in the liver.
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Affiliation(s)
- Yong Xu
- Division of Hypothalamic Research and Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
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39
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Chuang JC, Krishnan V, Yu HG, Mason B, Cui H, Wilkinson MB, Zigman JM, Elmquist JK, Nestler EJ, Lutter M, Lutter M. A beta3-adrenergic-leptin-melanocortin circuit regulates behavioral and metabolic changes induced by chronic stress. Biol Psychiatry 2010; 67:1075-82. [PMID: 20060958 PMCID: PMC2868111 DOI: 10.1016/j.biopsych.2009.12.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 11/20/2009] [Accepted: 12/01/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Obesity has been associated with an increased risk of developing several psychiatric illnesses, including major depression and posttraumatic stress disorder. Likewise, these stress-related disturbances are associated with a higher rate of obesity; yet, the neurobiological mechanisms linking obesity and stress remain incompletely understood. METHODS Following exposure to chronic social defeat stress (CSDS), mice were given free access to either regular chow or a Western-style diet high in triglycerides and cholesterol. Comprehensive metabolic and behavioral testing was then conducted. RESULTS Mice subjected to CSDS and then fed a high-fat diet for 30 days display severe behavioral deficits accompanied by redistribution of body fat. Stressed mice have decreased adipose tissue as well as decreased serum leptin levels compared with control mice. Pharmacological inhibition of beta(3)-adrenergic signaling during CSDS normalizes these metabolic abnormalities but worsens behavioral symptoms. Furthermore, mice subjected to CSDS display central leptin resistance including reduced expression of pro-opiomelanocortin in hypothalamus. Administration of a central melanocortin agonist worsens stress-induced behavioral deficits, while mice lacking the melanocortin-4 receptor display attenuated symptoms. CONCLUSIONS These results indicate that chronic signaling through beta(3)-adrenergic receptors during social stress is an adaptive response that improves behavioral function. However, these responses come at the expense of central leptin resistance and melanocortin signaling alterations that contribute to significant and long-lasting metabolic abnormalities.
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Affiliation(s)
- Jen-Chieh Chuang
- Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Vaishnav Krishnan
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Hana G. Yu
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Brittany Mason
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Huixing Cui
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
,
Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Matthew B. Wilkinson
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029-6574
| | - Jeffrey M. Zigman
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
,
Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Joel K. Elmquist
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
,
Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
,
Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Eric J. Nestler
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029-6574
| | - Michael Lutter
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
,
Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
,
To whom correspondence should be addressed.
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40
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Perello M, Sakata I, Birnbaum S, Chuang JC, Osborne-Lawrence S, Rovinsky SA, Woloszyn J, Yanagisawa M, Lutter M, Zigman JM. Ghrelin increases the rewarding value of high-fat diet in an orexin-dependent manner. Biol Psychiatry 2010; 67:880-6. [PMID: 20034618 PMCID: PMC2854245 DOI: 10.1016/j.biopsych.2009.10.030] [Citation(s) in RCA: 269] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 09/25/2009] [Accepted: 10/23/2009] [Indexed: 01/08/2023]
Abstract
BACKGROUND Ghrelin is a potent orexigenic hormone that likely impacts eating via several mechanisms. Here, we hypothesized that ghrelin can regulate extra homeostatic, hedonic aspects of eating behavior. METHODS In the current study, we assessed the effects of different pharmacological, physiological, and genetic models of increased ghrelin and/or ghrelin-signaling blockade on two classic behavioral tests of reward behavior: conditioned place preference (CPP) and operant conditioning. RESULTS Using both CPP and operant conditioning, we found that ghrelin enhanced the rewarding value of high-fat diet (HFD) when administered to ad lib-fed mice. Conversely, wild-type mice treated with ghrelin receptor antagonist and ghrelin receptor-null mice both failed to show CPP to HFD normally observed under calorie restriction. Interestingly, neither pharmacologic nor genetic blockade of ghrelin signaling inhibited the body weight homeostasis-related, compensatory hyperphagia associated with chronic calorie restriction. Also, ghrelin's effects on HFD reward were blocked in orexin-deficient mice and wild-type mice treated with an orexin 1 receptor antagonist. CONCLUSIONS Our results demonstrate an obligatory role for ghrelin in certain rewarding aspects of eating that is separate from eating associated with body weight homeostasis and that requires the presence of intact orexin signaling.
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Affiliation(s)
- Mario Perello
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Ichiro Sakata
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Shari Birnbaum
- Department of Psychiatry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Jen-Chieh Chuang
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Sherri Osborne-Lawrence
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Sherry A. Rovinsky
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Jakub Woloszyn
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Masashi Yanagisawa
- Department of Molecular Genetics and Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Michael Lutter
- Department of Psychiatry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
| | - Jeffrey M. Zigman
- Department of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism), The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077,Department of Psychiatry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9077
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41
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Hill JW, Elias CF, Fukuda M, Williams KW, Berglund ED, Holland WL, Cho YR, Chuang JC, Xu Y, Choi M, Lauzon D, Lee CE, Coppari R, Richardson JA, Zigman JM, Chua S, Scherer PE, Lowell BB, Brüning JC, Elmquist JK. Direct insulin and leptin action on pro-opiomelanocortin neurons is required for normal glucose homeostasis and fertility. Cell Metab 2010; 11:286-97. [PMID: 20374961 PMCID: PMC2854520 DOI: 10.1016/j.cmet.2010.03.002] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 10/30/2009] [Accepted: 03/05/2010] [Indexed: 02/03/2023]
Abstract
Circulating leptin and insulin convey information regarding energy stores to the central nervous system, particularly the hypothalamus. Hypothalamic pro-opiomelanocortin (POMC) neurons regulate energy balance and glucose homeostasis and express leptin and insulin receptors. However, the physiological significance of concomitant leptin and insulin action on POMC neurons remains to be established. Here, we show that mice lacking both leptin and insulin receptors in POMC neurons (Pomc-Cre, Lepr(flox/flox) IR(flox/flox) mice) display systemic insulin resistance, which is distinct from the single deletion of either receptor. In addition, Pomc-Cre, Lepr(flox/flox) IR(flox/flox) female mice display elevated serum testosterone levels and ovarian abnormalities, resulting in reduced fertility. We conclude that direct action of insulin and leptin on POMC neurons is required to maintain normal glucose homeostasis and reproductive function.
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Affiliation(s)
- Jennifer W Hill
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, College of Medicine, The University of Toledo, Toledo, OH 43614, USA
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42
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Ogihara T, Chuang JC, Vestermark GL, Garmey JC, Ketchum RJ, Huang X, Brayman KL, Thorner MO, Repa JJ, Mirmira RG, Evans-Molina C. Liver X receptor agonists augment human islet function through activation of anaplerotic pathways and glycerolipid/free fatty acid cycling. J Biol Chem 2010; 285:5392-404. [PMID: 20007976 PMCID: PMC2820768 DOI: 10.1074/jbc.m109.064659] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recent studies in rodent models suggest that liver X receptors (LXRs) may play an important role in the maintenance of glucose homeostasis and islet function. To date, however, no studies have comprehensively examined the role of LXRs in human islet biology. Human islets were isolated from non-diabetic donors and incubated in the presence or absence of two synthetic LXR agonists, TO-901317 and GW3965, under conditions of low and high glucose. LXR agonist treatment enhanced both basal and stimulated insulin secretion, which corresponded to an increase in the expression of genes involved in anaplerosis and reverse cholesterol transport. Furthermore, enzyme activity of pyruvate carboxylase, a key regulator of pyruvate cycling and anaplerotic flux, was also increased. Whereas LXR agonist treatment up-regulated known downstream targets involved in lipogenesis, we observed no increase in the accumulation of intra-islet triglyceride at the dose of agonist used in our study. Moreover, LXR activation increased expression of the genes encoding hormone-sensitive lipase and adipose triglyceride lipase, two enzymes involved in lipolysis and glycerolipid/free fatty acid cycling. Chronically, insulin gene expression was increased after treatment with TO-901317, and this was accompanied by increased Pdx-1 nuclear protein levels and enhanced Pdx-1 binding to the insulin promoter. In conclusion, our data suggest that LXR agonists have a direct effect on the islet to augment insulin secretion and expression, actions that should be considered either as therapeutic or unintended side effects, as these agents are developed for clinical use.
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Affiliation(s)
- Takeshi Ogihara
- From the Herman B Wells Center for Pediatric Research and
- the Departments of Pediatrics and
| | | | | | | | - Robert J. Ketchum
- the Department of Structural Medicine, Rocky Vista University, Parker, Colorado 80134
| | - Xiaolun Huang
- Surgery, University of Virginia, Charlottesville, Virginia 22904, and
| | | | | | - Joyce J. Repa
- the Departments of Physiology and
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Raghavendra G. Mirmira
- From the Herman B Wells Center for Pediatric Research and
- the Departments of Pediatrics and
- Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Carmella Evans-Molina
- From the Herman B Wells Center for Pediatric Research and
- Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
- To whom correspondence should be addressed: Indiana University School of Medicine, 635 Barnhill Dr., MS 2031A, Indianapolis, IN 46202. Tel.: 317-274-4145; Fax: 317-274-4107; E-mail:
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Chuang JC, Cui H, Mason BL, Mahgoub M, Bookout AL, Yu HG, Perello M, Elmquist JK, Repa JJ, Zigman JM, Lutter M. Chronic social defeat stress disrupts regulation of lipid synthesis. J Lipid Res 2010; 51:1344-53. [PMID: 20129912 DOI: 10.1194/jlr.m002196] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Several psychiatric disorders increase the risk of cardiovascular disease, including posttraumatic stress disorder and major depression. While the precise mechanism for this association has not yet been established, it has been shown that certain disorders promote an unfavorable lipid profile. To study the interaction of stress and lipid dysregulation, we utilized chronic social defeat stress (CSDS), a mouse model of chronic stress with features of posttraumatic stress disorder and major depression. Following exposure to CSDS, mice were given access to either regular chow or a Western-style diet high in fat and cholesterol (HFD). The combination of social stress and HFD resulted in significant perturbations in lipid regulation, including two key features of the metabolic syndrome: increased plasma levels of non-HDL cholesterol and intrahepatic accumulation of triglycerides. These effects were accompanied by a number of changes in the expression of hepatic genes involved in lipid regulation. Transcriptional activity of LXR, SREBP1c, and ChREBP were significantly affected by exposure to HFD and CSDS. We present CSDS as a model of social stress induced lipid dysregulation and propose that social stress alters lipid metabolism by increasing transcriptional activity of genes involved in lipid synthesis.
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Affiliation(s)
- Jen-Chieh Chuang
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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44
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Chuang JC, Cha JY, Garmey JC, Mirmira RG, Repa JJ. Research resource: nuclear hormone receptor expression in the endocrine pancreas. Mol Endocrinol 2008; 22:2353-63. [PMID: 18669644 DOI: 10.1210/me.2007-0568] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The endocrine pancreas comprises the islets of Langerhans, tiny clusters of cells that contribute only about 2% to the total pancreas mass. However, this little endocrine organ plays a critical role in maintaining glucose homeostasis by the regulated secretion of insulin (by beta-cells) and glucagon (by alpha-cells). The rapid increase in the incidence of diabetes worldwide has spurred renewed interest in islet cell biology. Some of the most widely prescribed oral drugs for treating type 2 diabetes include agents that bind and activate the nuclear hormone receptor, peroxisome proliferator-activated receptor-gamma. As a first step in addressing potential roles of peroxisome proliferator-activated receptor-gamma and other nuclear hormone receptors (NHRs) in the biology of the endocrine pancreas, we have used quantitative real-time PCR to profile the expression of all 49 members of the mouse NHR superfamily in primary islets, and cell lines that represent alpha-cells (alphaTC1) and beta-cells (betaTC6 and MIN6). In summary, 19 NHR members were highly expressed in both alpha- and beta-cell lines, 13 receptors showed predominant expression (at least an 8-fold difference) in alpha- vs. beta-cell lines, and 10 NHRs were not expressed in the endocrine pancreas. In addition we evaluated the relative expression of these transcription factors during hyperglycemia and found that 16 NHRs showed significantly altered mRNA levels in mouse islets. A similar survey was conducted in primary human islets to reveal several significant differences in NHR expression between mouse and man. These data identify potential therapeutic targets in the endocrine pancreas for the treatment of diabetes mellitus.
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Affiliation(s)
- Jen-Chieh Chuang
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9077, USA
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45
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Chuang JC, Van Emon JM, Finegold JK, Chou YL, Rubio F. Immunoassay method for the determination of pentachlorophenol in soil and sediment. Bull Environ Contam Toxicol 2006; 76:381-8. [PMID: 16652249 DOI: 10.1007/s00128-006-0932-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 12/27/2005] [Indexed: 05/08/2023]
Affiliation(s)
- J C Chuang
- Batelle, 505 King Avenue, Columbus, OH 43201-2693, USA
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Rhodes VL, Kriek G, Lazear N, Kasakevich J, Martinko M, Heggs RP, Holdren MW, Wisbith AS, Keigley GW, Williams JD, Chuang JC, Satola JR. Development of emission factors for polycarbonate processing. J Air Waste Manag Assoc 2002; 52:781-788. [PMID: 12139342 DOI: 10.1080/10473289.2002.10470820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.
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Affiliation(s)
- Verne L Rhodes
- Product Regulatory Services, Inc., Gulf Breeze, Florida, USA
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Liu Q, Marrs JA, Chuang JC, Raymond PA. Cadherin-4 expression in the zebrafish central nervous system and regulation by ventral midline signaling. Brain Res Dev Brain Res 2001; 131:17-29. [PMID: 11718832 DOI: 10.1016/s0165-3806(01)00241-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this study we show that zebrafish cadherin-4 (R-cadherin) transcript (cad4) and protein are expressed in several defined regions in the embryonic forebrain and in distinctive clusters in the hindbrain and spinal cord. This is the first report of a segmental pattern of expression of cadherin-4 in the hindbrain and spinal cord. Expression domains of cadherin-4 transcript and protein were compared with that of pax6.1. In the forebrain of zebrafish embryos, cad4 and pax6.1 expression domains overlapped extensively, although they were not completely coincident. Injection of pax6.1 mRNA resulted in an increase in cad4 expression, whereas overexpression of sonic hedgehog (shh), a midline signaling molecule that reduces pax6.1 expression, caused a reduction in cad4 expression throughout the brain. cad4 expression was increased in both forebrain and hindbrain in cyclops mutant embryos, which have a defect in midline signaling and an enlarged expression domain of pax6.1. These results suggest that zebrafish cadherin-4 may play a role in organization of neuronal architecture throughout the neural axis, and that its expression is regulated by a ventral midline signaling pathway that involves shh and pax6.1.
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Affiliation(s)
- Q Liu
- Department of Biology, University of Akron, Akron, OH 44325-3908, USA.
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Wilson NK, Chuang JC, Lyu C. Levels of persistent organic pollutants in several child day care centers. J Expo Anal Environ Epidemiol 2001; 11:449-58. [PMID: 11791162 DOI: 10.1038/sj.jea.7500190] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2001] [Indexed: 04/17/2023]
Abstract
The concentrations of a suite of persistent organic chemicals were measured in multiple media in 10 child day care centers located in central North Carolina. Five centers served mainly children from low-income families, as defined by the federal Women, Infants, and Children (WIC) assistance program, and five served mainly children from middle-income families. The targeted chemicals were chosen because of their probable carcinogenicity, acute or chronic toxicity, or hypothesized potential for endocrine system disruption. Targeted compounds included polycyclic aromatic hydrocarbons (PAHs), pentachloro- and nonyl-phenol, bisphenol-A, dibutyl and butylbenzyl phthalate, polychlorinated biphenyls (PCBs), organochlorine pesticides, the organophosphate pesticides diazinon and chlorpyrifos, and the herbicide 2,4-dichlorophenoxyacetic acid (2,4D). Sampled media were indoor and outdoor air, food and beverages, indoor dust, and outdoor play area soil. Concentrations of the targeted compounds were determined using a combination of extraction and analysis methods, depending on the media. Analysis was predominantly by gas chromatography/mass spectrometry (GC/MS) or gas chromatography with electron capture detection (GC/ECD). Concentrations of the targeted pollutants were low and well below the levels generally considered to be of concern as possible health hazards. Potential exposures to the target compounds were estimated from the concentrations in the various media, the children's daily time-activity schedules at day care, and the best currently available estimates of the inhalation rates (8.3 m(3)/day) and soil ingestion rates (100 mg/day) of children ages 3-5. The potential exposures for the target compounds differed depending on the compound class and the sampled media. Potential exposures through dietary ingestion were greater than those through inhalation, which were greater than those through nondietary ingestion, for the total of all PAHs, the phenols, the organophosphate pesticides, and the organochlorine pesticides. Potential exposures through dietary ingestion were greater than those through nondietary ingestion, which were greater than those through inhalation, for those PAHs that are probable human carcinogens (B2 PAH), the phthalate esters, and 2,4D. For the PCBs, exposures through inhalation were greater than those through nondietary ingestion, and exposures through dietary ingestion were smallest. Differences in targeted compound levels between the centers that serve mainly low-income clients and those that serve mainly middle-income clients were small and depended on the compound class and the medium.
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Kriek G, Lazear N, Rhodes V, Barnes J, Bollmeier J, Chuang JC, Holdren MW, Wisbith AS, Hayward J, Pietrzyk D. Development of emission factors for polyamide processing. J Air Waste Manag Assoc 2001; 51:1001-1008. [PMID: 15658219 DOI: 10.1080/10473289.2001.10464329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Emission factors for selected volatile organic compounds (VOCs) and particulate material were developed during processing of commercial grades of polyamide 6, polyamide 66, and polyamide 66/6 resins. A small commercial-type extruder was used, and melt temperatures ranged from 475 to 550 degrees F. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere per million pounds of polymer resin processed. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar polyamide extrusion operations.
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Affiliation(s)
- G Kriek
- Bayer Corporation, Pittsburgh, Pennsylvania, USA
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Abstract
Zebrafish retinal homeobox genes rx1 and rx2 are expressed exclusively in the optic primordia and then in cone photoreceptors of the differentiated neural retina. In this study, we show that the rx expression domain is coextensive with the region identified as the retinal field in published fate maps of the neural plate in zebrafish embryos. Analysis of the spatiotemporal relationships between retinal and forebrain precursors suggests that lateral movement of retinal precursors is responsible for evagination of the optic primordia. Overexpression of either rx1 or rx2 results in the loss of forebrain tissue and the ectopic formation of retinal tissue. We asked whether the deletion of forebrain and expansion of retinal tissue could be explained by the death of telencephalic precursors and enhanced proliferation of retinal precursors, and we found that it could not. Instead, our data are consistent with a change in cell fate of forebrain precursors associated with reduced expression of telencephalic markers (emx1 and BF-1) and ectopic expression of retinal markers (rx1/2/3, pax6, six6, and vsx2) at the neural keel stage. The rx homeodomain alone is sufficient to induce ectopic retinal tissue, although weakly so, and this observation, together with results from deletion constructs, suggests that interactions with unidentified transcriptional regulators are important for rx1 and rx2 function during early eye development. We conclude that regulated expression of zebrafish rx1 and rx2 helps to define the region of the forebrain fated to give rise to retinal tissue and may be involved in the cellular migrations that lead to splitting of the retinal field and formation of the optic primordia.
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Affiliation(s)
- J C Chuang
- Program in Cell, Developmental, and Neural Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0616, USA
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