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Seramur ME, Sink S, Cox AO, Furdui CM, Key CCC. ABHD4 regulates adipocyte differentiation in vitro but does not affect adipose tissue lipid metabolism in mice. J Lipid Res 2023; 64:100405. [PMID: 37352974 PMCID: PMC10400869 DOI: 10.1016/j.jlr.2023.100405] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 05/02/2023] [Accepted: 06/10/2023] [Indexed: 06/25/2023] Open
Abstract
Alpha/beta hydrolase domain-containing protein 4 (ABHD4) catalyzes the deacylation of N-acyl phosphatidyl-ethanolamine (NAPE) and lyso-NAPE to produce glycerophospho-N-acyl ethanolamine (GP-NAE). Through a variety of metabolic enzymes, NAPE, lyso-NAPE, and GP-NAE are ultimately converted into NAE, a group of bioactive lipids that control many physiological processes including inflammation, cognition, food intake, and lipolysis (i.e., oleoylethanolamide or OEA). In a diet-induced obese mouse model, adipose tissue Abhd4 gene expression positively correlated with adiposity. However, it is unknown whether Abhd4 is a causal or a reactive gene to obesity. To fill this knowledge gap, we generated an Abhd4 knockout (KO) 3T3-L1 pre-adipocyte. During adipogenic stimulation, Abhd4 KO pre-adipocytes had increased adipogenesis and lipid accumulation, suggesting Abhd4 is responding to (a reactive gene), not contributing to (not a causal gene), adiposity, and may serve as a mechanism for protecting against obesity. However, we did not observe any differences in adiposity and metabolic outcomes between whole-body Abhd4 KO or adipocyte-specific Abhd4 KO mice and their littermate control mice (both male and female) on chow or a high-fat diet. This might be because we found that deletion of Abhd4 did not affect NAE such as OEA production, even though Abhd4 was highly expressed in adipose tissue and correlated with fasting adipose OEA levels and lipolysis. These data suggest that ABHD4 regulates adipocyte differentiation in vitro but does not affect adipose tissue lipid metabolism in mice despite nutrient overload, possibly due to compensation from other NAPE and NAE metabolic enzymes.
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Affiliation(s)
- Mary E Seramur
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston Salem, NC, USA
| | - Sandy Sink
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston Salem, NC, USA
| | - Anderson O Cox
- Wake Forest Baptist Comprehensive Cancer Center Proteomics and Metabolomics Shared Resource, Wake Forest University School of Medicine, Winston Salem, NC, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston Salem, NC, USA
| | - Chia-Chi Chuang Key
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston Salem, NC, USA.
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Sundaram AK, Ewing D, Blevins M, Liang Z, Sink S, Lassan J, Raviprakash K, Defang G, Williams M, Porter KR, Sanders JW. Comparison of purified psoralen-inactivated and formalin-inactivated dengue vaccines in mice and nonhuman primates. Vaccine 2020; 38:3313-3320. [PMID: 32184032 DOI: 10.1016/j.vaccine.2020.03.008] [Citation(s) in RCA: 8] [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: 11/29/2019] [Revised: 02/27/2020] [Accepted: 03/01/2020] [Indexed: 02/06/2023]
Abstract
Dengue fever, caused by dengue viruses (DENV 1-4) is a leading cause of illness and death in the tropics and subtropics. Therefore, an effective vaccine is urgently needed. Currently, the only available licensed dengue vaccine is a chimeric live attenuated vaccine that shows varying efficacy depending on serotype, age and baseline DENV serostatus. Accordingly, a dengue vaccine that is effective in seronegative adults, children of all ages and in immunocompromised individuals is still needed. We are currently researching the use of psoralen to develop an inactivated tetravalent dengue vaccine. Unlike traditional formalin inactivation, psoralen inactivates pathogens at the nucleic acid level, potentially preserving envelope protein epitopes important for protective anti-dengue immune responses. We prepared highly purified monovalent vaccine lots of formalin- and psoralen-inactivated DENV 1-4, using Capto DeVirS and Capto Core 700 resin based column chromatography. Tetravalent psoralen-inactivated vaccines (PsIV) and formalin-inactivated vaccines (FIV) were prepared by combining the four monovalent vaccines. Mice were immunized with either a low or high dose of PsIV or FIV to evaluate the immunogenicity of monovalent as well as tetravalent formulations of each inactivation method. In general, the monovalent and tetravalent PsIVs elicited equivalent or higher titers of neutralizing antibodies to DENV than the FIV dengue vaccines and this response was dose dependent. The immunogenicity of tetravalent dengue PsIVs and FIVs were also evaluated in nonhuman primates (NHPs). Consistent with what was observed in mice, significantly higher neutralizing antibody titers for each dengue serotype were observed in the NHPs vaccinated with the tetravalent dengue PsIV compared to those vaccinated with the tetravalent dengue FIV, indicative of the importance of envelope protein epitope preservation during psoralen inactivation of DENV.
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Affiliation(s)
- Appavu K Sundaram
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817, USA.
| | - Daniel Ewing
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Maria Blevins
- Section on Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Zhaodong Liang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817, USA
| | - Sandy Sink
- Section on Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Josef Lassan
- Section on Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Kanakatte Raviprakash
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Gabriel Defang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Maya Williams
- Infectious Diseases Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Kevin R Porter
- Infectious Diseases Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - John W Sanders
- Section on Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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Salaye L, Bychkova I, Sink S, Kovalic AJ, Bharadwaj MS, Lorenzo F, Jain S, Harrison AV, Davis AT, Turnbull K, Meegalla NT, Lee SH, Cooksey R, Donati GL, Kavanagh K, Bonkovsky HL, McClain DA. A Low Iron Diet Protects from Steatohepatitis in a Mouse Model. Nutrients 2019; 11:nu11092172. [PMID: 31510077 PMCID: PMC6769937 DOI: 10.3390/nu11092172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 08/31/2019] [Accepted: 09/06/2019] [Indexed: 02/07/2023] Open
Abstract
High tissue iron levels are a risk factor for multiple chronic diseases including type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). To investigate causal relationships and underlying mechanisms, we used an established NAFLD model-mice fed a high fat diet with supplemental fructose in the water ("fast food", FF). Iron did not affect excess hepatic triglyceride accumulation in the mice on FF, and FF did not affect iron accumulation compared to normal chow. Mice on low iron are protected from worsening of markers for non-alcoholic steatohepatitis (NASH), including serum transaminases and fibrotic gene transcript levels. These occurred prior to the onset of significant insulin resistance or changes in adipokines. Transcriptome sequencing revealed the major effects of iron to be on signaling by the transforming growth factor beta (TGF-β) pathway, a known mechanistic factor in NASH. High iron increased fibrotic gene expression in vitro, demonstrating that the effect of dietary iron on NASH is direct. Conclusion: A lower tissue iron level prevents accelerated progression of NAFLD to NASH, suggesting a possible therapeutic strategy in humans with the disease.
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Affiliation(s)
- Lipika Salaye
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
| | - Ielizaveta Bychkova
- Department of Internal Medicine, University of Utah Medical Center, Salt Lake City, UT 84112, USA
| | - Sandy Sink
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
| | - Alexander J Kovalic
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Manish S Bharadwaj
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
- Agilent Technologies, 121 Hartwell Ave, Lexington, MA 02421, USA
| | - Felipe Lorenzo
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
| | - Shalini Jain
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
| | - Alexandria V Harrison
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
| | - Ashley T Davis
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27157, USA
| | - Katherine Turnbull
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27157, USA
| | - Nuwan T Meegalla
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Soh-Hyun Lee
- Department of Internal Medicine, University of Utah Medical Center, Salt Lake City, UT 84112, USA
| | - Robert Cooksey
- Department of Internal Medicine, University of Utah Medical Center, Salt Lake City, UT 84112, USA
- VA Medical Center, Salt Lake City, UT 84148, USA
| | - George L Donati
- Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Kylie Kavanagh
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27157, USA
- Department of Biomedicine, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Herbert L Bonkovsky
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Donald A McClain
- Center on Diabetes, Obesity and Metabolism, Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC 27101, USA.
- VA Medical Center, Salt Lake City, UT 84148, USA.
- VA Medical Center, Salisbury, NC 28144, USA.
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Gao Y, Liu J, Bai Z, Sink S, Zhao C, Lorenzo FR, McClain DA. Iron down-regulates leptin by suppressing protein O-GlcNAc modification in adipocytes, resulting in decreased levels of O-glycosylated CREB. J Biol Chem 2019; 294:5487-5495. [PMID: 30709903 DOI: 10.1074/jbc.ra118.005183] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [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: 08/04/2018] [Revised: 01/28/2019] [Indexed: 11/06/2022] Open
Abstract
We previously reported that iron down-regulates transcription of the leptin gene by increasing occupancy of phosphorylated cAMP response element-binding protein (pCREB) at two sites in the leptin gene promoter. Several nutrient-sensing pathways including O-GlcNAcylation also regulate leptin. We therefore investigated whether O-glycosylation plays a role in iron- and CREB-mediated regulation of leptin. We found that high iron decreases protein O-GlcNAcylation both in cultured 3T3-L1 adipocytes and in mice fed high-iron diets and down-regulates leptin mRNA and protein levels. Glucosamine treatment, which bypasses the rate-limiting step in the synthesis of substrate for glycosylation, increased both O-GlcNAc and leptin, whereas inhibition of O-glycosyltransferase (OGT) decreased O-GlcNAc and leptin. The increased leptin levels induced by glucosamine were susceptible to the inhibition by iron, but in the case of OGT inhibition, iron did not further decrease leptin. Mice with deletion of the O-GlcNAcase gene, either via whole-body heterozygous deletion or through adipocyte-targeted homozygous deletion, exhibited increased O-GlcNAc levels in adipose tissue and increased leptin levels that were inhibited by iron. Of note, iron increased the occupancy of pCREB and decreased the occupancy of O-GlcNAcylated CREB on the leptin promoter. These patterns observed in our experimental models suggest that iron exerts its effects on leptin by decreasing O-glycosylation and not by increasing protein deglycosylation and that neither O-GlcNAcase nor OGT mRNA and protein levels are affected by iron. We conclude that iron down-regulates leptin by decreasing CREB glycosylation, resulting in increased CREB phosphorylation and leptin promoter occupancy by pCREB.
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Affiliation(s)
- Yan Gao
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Jingfang Liu
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Zhenzhong Bai
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Sandy Sink
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Chengyu Zhao
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Felipe Ramos Lorenzo
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and
| | - Donald A McClain
- From the Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina 27157 and .,the W. G. Hefner Veterans Affairs Medical Center, Salisbury, North Carolina 28144
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Nam H, Jones D, Cooksey RC, Gao Y, Sink S, Cox J, McClain DA. Synergistic Inhibitory Effects of Hypoxia and Iron Deficiency on Hepatic Glucose Response in Mouse Liver. Diabetes 2016; 65:1521-33. [PMID: 26993063 PMCID: PMC4878425 DOI: 10.2337/db15-0580] [Citation(s) in RCA: 8] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 03/05/2016] [Indexed: 01/28/2023]
Abstract
Hypoxia and iron both regulate metabolism through multiple mechanisms, including hypoxia-inducible transcription factors. The hypoxic effects on glucose disposal and glycolysis are well established, but less is known about the effects of hypoxia and iron deficiency on hepatic gluconeogenesis. We therefore assessed their effects on hepatic glucose production in mice. Weanling C57BL/6 male mice were fed an iron-deficient (4 ppm) or iron-adequate (35 ppm) diet for 14 weeks and were continued in normoxia or exposed to hypoxia (8% O2) for the last 4 weeks of that period. Hypoxic mice became hypoglycemic and displayed impaired hepatic glucose production after a pyruvate challenge, an effect accentuated by an iron-deficient diet. Stabilization of hypoxia-inducible factors under hypoxia resulted in most glucose being converted into lactate and not oxidized. Hepatic pyruvate concentrations were lower in hypoxic mice. The decreased hepatic pyruvate levels were not caused by increased utilization but rather were contributed to by decreased metabolism from gluconeogenic amino acids. Pyruvate carboxylase, which catalyzes the first step of gluconeogenesis, was also downregulated by hypoxia with iron deficiency. Hypoxia, and more so hypoxia with iron deficiency, results in hypoglycemia due to decreased levels of hepatic pyruvate and decreased pyruvate utilization for gluconeogenesis. These data highlight the role of iron levels as an important determinant of glucose metabolism in hypoxia.
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Affiliation(s)
- Hyeyoung Nam
- Department of Internal Medicine, University of Utah, Salt Lake City, UT
| | - Deborah Jones
- Department of Internal Medicine, University of Utah, Salt Lake City, UT
| | - Robert C Cooksey
- Department of Internal Medicine, University of Utah, Salt Lake City, UT
| | - Yan Gao
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - Sandy Sink
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - James Cox
- Department of Biochemistry, University of Utah, Salt Lake City, UT
| | - Donald A McClain
- Department of Internal Medicine, University of Utah, Salt Lake City, UT Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC Department of Biochemistry, University of Utah, Salt Lake City, UT
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