1
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Xu C, Li H, Tang CK. Sterol carrier protein 2 in lipid metabolism and non-alcoholic fatty liver disease: Pathophysiology, molecular biology, and potential clinical implications. Metabolism 2022; 131:155180. [PMID: 35311663 DOI: 10.1016/j.metabol.2022.155180] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/03/2022] [Accepted: 03/13/2022] [Indexed: 11/29/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is considered as the most common chronic liver disease and has become a rapidly global public health problem. Sterol carrier protein 2 (SCP-2), also called non-specific lipid-transfer protein, is predominantly expressed by the liver. SCP-2 plays a key role in intracellular lipid transport and metabolism. SCP-2 has been closely implicated in the development of NAFLD-related metabolic disorders, such as obesity, atherosclerosis, Type 2 diabetes mellitus (T2DM), and gallstones. Recent studies indicate that SCP-2 plays a beneficial role in NAFLD by regulating cholesterol-, endocannabinoid-, and fatty acid-related aspects of lipid metabolism. Hence, in this paper, we summarize the latest findings about the roles of SCP-2 in hepatic steatosis and further describe its molecular function in the pathogenesis of NAFLD.
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Affiliation(s)
- Can Xu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, The First Affiliated Hospital of University of South China, Department of Cardiology, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, PR China
| | - Heng Li
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, The First Affiliated Hospital of University of South China, Department of Cardiology, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, PR China.
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, The First Affiliated Hospital of University of South China, Department of Cardiology, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, PR China.
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2
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Jia Z, Zhao C, Wang M, Zhao X, Zhang W, Han T, Xia Q, Han Z, Lin R, Li X. Hepatotoxicity assessment of Rhizoma Paridis in adult zebrafish through proteomes and metabolome. Biomed Pharmacother 2020; 121:109558. [DOI: 10.1016/j.biopha.2019.109558] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 10/08/2019] [Accepted: 10/17/2019] [Indexed: 12/20/2022] Open
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3
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McIntosh AL, Atshaves BP, Martin GG, Landrock D, Milligan S, Landrock KK, Huang H, Storey SM, Mackie J, Schroeder F, Kier AB. Effect of liver fatty acid binding protein (L-FABP) gene ablation on lipid metabolism in high glucose diet (HGD) pair-fed mice. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:985-1004. [PMID: 30910689 PMCID: PMC6482111 DOI: 10.1016/j.bbalip.2019.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/02/2019] [Accepted: 03/21/2019] [Indexed: 01/06/2023]
Abstract
Liver fatty acid binding protein (L-FABP) is the major fatty acid binding/"chaperone" protein in hepatic cytosol. Although fatty acids can be derived from the breakdown of dietary fat and glucose, relatively little is known regarding the impact of L-FABP on phenotype in the context of high dietary glucose. Potential impact was examined in wild-type (WT) and Lfabp gene ablated (LKO) female mice fed either a control or pair-fed high glucose diet (HGD). WT mice fed HGD alone exhibited decreased whole body weight gain and weight gain/kcal food consumed-both as reduced lean tissue mass (LTM) and fat tissue mass (FTM). Conversely, LKO alone increased weight gain, lean tissue mass, and fat tissue mass while decreasing serum β-hydroxybutyrate (indicative of hepatic fatty acid oxidation)-regardless of diet. Both LKO alone and HGD alone significantly altered the serum lipoprotein profile and increased triacylglycerol (TG), but in HGD mice the LKO did not further exacerbate serum TG content. HGD had little effect on hepatic lipid composition in WT mice, but prevented the LKO-induced selective increase in hepatic phospholipid, free-cholesterol and cholesteryl-ester. Taken together, these findings suggest that high glucose diet diminished the effects of LKO on the whole body and lipid phenotype of these mice.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Barbara P Atshaves
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America
| | - Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Sherrelle Milligan
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Huan Huang
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - John Mackie
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843, United States of America
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843, United States of America.
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4
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Xie L, Zhang Y, Li X, Chai L, Wang H. Exposure to nitrate alters the histopathology and gene expression in the liver of Bufo gargarizans tadpoles. CHEMOSPHERE 2019; 217:308-319. [PMID: 30419385 DOI: 10.1016/j.chemosphere.2018.11.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/17/2018] [Accepted: 11/03/2018] [Indexed: 06/09/2023]
Abstract
Nitrate is a ubiquitous component in aquatic environment and the concentrations of anthropogenic nitrate-nitrogen (NO3N) can exceed 25 mg/L in surface waters and 100 mg/L in ground waters. The exceed nitrate has adverse effects on survival, development, and metamorphosis of amphibian. Liver is the hub of many biological processes, including lipid metabolism and bile salts secretion. However, there is little information about the effects of nitrate on the liver in amphibians during metamorphosis. In this study, B. gargarizans was exposed to different concentrations of nitrate from embryo to metamorphosis climax to investigate the effects of nitrate on the liver. The survival rate, metamorphosis percent, body mass, total length, and hind-limb length were measured. The histopathological changes and transcriptome responses in the liver of B. gargarizans to nitrate were examined. Results indicated exposure to 50 and 100 mg/L NO3N delayed the metamorphosis and decreased the metamorphosis percent of B. gargarizans. The body size of B. gargarizans at 10 and 50 mg/L NO3N groups were decreased while it was increased at 100 mg/L NO3N group. In addition, exposure to 100 mg/L NO3N caused severe histopathological changes, including cellular atrophy, increased intercellular areas, degraded lipid droplets, hepatic fibrosis, bile canaliculus contraction and degraded mitochondria in liver. The results of RNA-seq and qRT-PCR interpreted the molecular responses, which might be the factors to induce histopathological changes in the liver of B. gargarizans under the pressure of nitrate exposure.
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Affiliation(s)
- Lei Xie
- College of Life Science, Shaanxi Normal University, Xi'an, 710119, China
| | - Yuhui Zhang
- College of Life Science, Shaanxi Normal University, Xi'an, 710119, China
| | - Xinyi Li
- College of Life Science, Shaanxi Normal University, Xi'an, 710119, China
| | - Lihong Chai
- School of Environmental Science and Engineering, Chang'an University, Xi'an, 710054, China; Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Xi'an, 710062, China
| | - Hongyuan Wang
- College of Life Science, Shaanxi Normal University, Xi'an, 710119, China.
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5
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Huang H, McIntosh AL, Martin GG, Dangott LJ, Kier AB, Schroeder F. Structural and Functional Interaction of Δ 9-Tetrahydrocannabinol with Liver Fatty Acid Binding Protein (FABP1). Biochemistry 2018; 57:6027-6042. [PMID: 30232874 DOI: 10.1021/acs.biochem.8b00744] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although serum Δ9-tetrahydrocannabinol (Δ9-THC) undergoes rapid hepatic clearance and metabolism, almost nothing is known regarding the mechanism(s) whereby this highly lipophilic phytocannabinoid is transported for metabolism/excretion. A novel NBD-arachidonoylethanolamide (NBD-AEA) fluorescence displacement assay showed that liver fatty acid binding protein (FABP1), the major hepatic endocannabinoid (EC) binding protein, binds the first major metabolite of Δ9-THC (Δ9-THC-OH) as well as Δ9-THC itself. Circular dichroism (CD) confirmed that not only Δ9-THC and Δ9-THC-OH but also downstream metabolites Δ9-THC-COOH and Δ9-THC-CO-glucuronide directly interact with FABP1. Δ9-THC and metabolite interaction differentially altered the FABP1 secondary structure, increasing total α-helix (all), decreasing total β-sheet (Δ9-THC-COOH, Δ9-THC-CO-glucuronide), increasing turns (Δ9-THC-OH, Δ9-THC-COOH, Δ9-THC-CO-glucuronide), and decreasing unordered structure (Δ9-THC, Δ9-THC-OH). Cultured primary hepatocytes from wild-type (WT) mice took up and converted Δ9-THC to the above metabolites. Fabp1 gene ablation (LKO) dramatically increased hepatocyte accumulation of Δ9-THC and even more so its primary metabolites Δ9-THC-OH and Δ9-THC-COOH. Concomitantly, rtPCR and Western blotting indicated that LKO significantly increased Δ9-THC's ability to regulate downstream nuclear receptor transcription of genes important in both EC ( Napepld > Daglb > Dagla, Naaa, Cnr1) and lipid ( Cpt1A > Fasn, FATP4) metabolism. Taken together, the data indicated that FABP1 may play important roles in Δ9-THC uptake and elimination as well as Δ9-THC induction of genes regulating hepatic EC levels and downstream targets in lipid metabolism.
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Affiliation(s)
- Huan Huang
- Department of Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843-4466 , United States
| | - Avery L McIntosh
- Department of Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843-4466 , United States
| | - Gregory G Martin
- Department of Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843-4466 , United States
| | - Lawrence J Dangott
- Protein Chemistry Laboratory , Texas A&M University , College Station , Texas 77843-2128 , United States
| | - Ann B Kier
- Department of Pathobiology , Texas A&M University , College Station , Texas 77843-4467 , United States
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843-4466 , United States
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6
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He H, Wang J, Yannie PJ, Kakiyama G, Korzun WJ, Ghosh S. Sterol carrier protein-2 deficiency attenuates diet-induced dyslipidemia and atherosclerosis in mice. J Biol Chem 2018; 293:9223-9231. [PMID: 29700117 DOI: 10.1074/jbc.ra118.002290] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/25/2018] [Indexed: 01/05/2023] Open
Abstract
Intracellular cholesterol transport proteins move cholesterol to different subcellular compartments and thereby regulate its final metabolic fate. In hepatocytes, for example, delivery of high-density lipoprotein (HDL)-associated cholesterol for bile acid synthesis or secretion into bile facilitates cholesterol elimination from the body (anti-atherogenic effect), whereas delivery for esterification and subsequent incorporation into apolipoprotein B-containing atherogenic lipoproteins (e.g. very-low-density lipoprotein (VLDL)) enhances cholesterol secretion into the systemic circulation (pro-atherogenic effect). Intracellular cholesterol transport proteins such as sterol carrier protein-2 (SCP2) should, therefore, play a role in regulating these pro- or anti-atherosclerotic processes. Here, we sought to evaluate the effects of SCP2 deficiency on the development of diet-induced atherosclerosis. We generated LDLR-/- mice deficient in SCP2/SCPx (LS) and examined the effects of this deficiency on Western diet-induced atherosclerosis. SCP2/SCPx deficiency attenuated atherosclerosis in LS mice by >80% and significantly reduced plasma cholesterol and triglyceride levels. Investigation of the likely underlying mechanisms revealed a significant reduction in intestinal cholesterol absorption (given as an oral gavage) in SCP2/SCPx-deficient mice. Consistently, siRNA-mediated knockdown of SCP2 in intestinal cells significantly reduced cholesterol uptake. Furthermore, hepatic triglyceride/VLDL secretion from the liver or hepatocytes isolated from SCP2/SCPx-deficient mice was significantly reduced. These results indicate an important regulatory role for SCP2 deficiency in attenuating diet-induced atherosclerosis by limiting intestinal cholesterol absorption and decreasing hepatic triglyceride/VLDL secretion. These findings suggest targeted inhibition of SCP2 as a potential therapeutic strategy to reduce Western diet-induced dyslipidemia and atherosclerosis.
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Affiliation(s)
| | - Jing Wang
- From the Departments of Internal Medicine and
| | - Paul J Yannie
- the Hunter Homes McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249
| | - Genta Kakiyama
- the Hunter Homes McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249
| | - William J Korzun
- Clinical and Laboratory Sciences, Virginia Commonwealth University (VCU) Medical Center, Richmond, Virginia 23298 and
| | - Shobha Ghosh
- From the Departments of Internal Medicine and .,the Hunter Homes McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249
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7
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Busnelli M, Manzini S, Parolini C, Escalante-Alcalde D, Chiesa G. Lipid phosphate phosphatase 3 in vascular pathophysiology. Atherosclerosis 2018. [DOI: 10.1016/j.atherosclerosis.2018.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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8
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Milligan S, Martin GG, Landrock D, McIntosh AL, Mackie JT, Schroeder F, Kier AB. Ablating both Fabp1 and Scp2/Scpx (TKO) induces hepatic phospholipid and cholesterol accumulation in high fat-fed mice. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:323-338. [PMID: 29307784 DOI: 10.1016/j.bbalip.2017.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/13/2017] [Accepted: 12/31/2017] [Indexed: 01/16/2023]
Abstract
Although singly ablating Fabp1 or Scp2/Scpx genes may exacerbate the impact of high fat diet (HFD) on whole body phenotype and non-alcoholic fatty liver disease (NAFLD), concomitant upregulation of the non-ablated gene, preference for ad libitum fed HFD, and sex differences complicate interpretation. Therefore, these issues were addressed in male and female mice ablated in both genes (Fabp1/Scp2/Scpx null or TKO) and pair-fed HFD. Wild-type (WT) males gained more body weight as fat tissue mass (FTM) and exhibited higher hepatic lipid accumulation than WT females. The greater hepatic lipid accumulation in WT males was associated with higher hepatic expression of enzymes in glyceride synthesis, higher hepatic bile acids, and upregulation of transporters involved in hepatic reuptake of serum bile acids. While TKO had little effect on whole body phenotype and hepatic bile acid accumulation in either sex, TKO increased hepatic accumulation of lipids in both, specifically phospholipid and cholesteryl esters in males and females and free cholesterol in females. TKO-induced increases in glycerides were attributed not only to complete loss of FABP1, SCP2 and SCPx, but also in part to sex-dependent upregulation of hepatic lipogenic enzymes. These data with WT and TKO mice pair-fed HFD indicate that: i) Sex significantly impacted the ability of HFD to increase body weight, induce hepatic lipid accumulation and increase hepatic bile acids; and ii) TKO exacerbated the HFD ability to induce hepatic lipid accumulation, regardless of sex, but did not significantly alter whole body phenotype in either sex.
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Affiliation(s)
- Sherrelle Milligan
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Gregory G Martin
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - Danilo Landrock
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Avery L McIntosh
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - John T Mackie
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA.
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9
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McIntosh AL, Storey SM, Huang H, Kier AB, Schroeder F. Sex-dependent impact of Scp-2/Scp-x gene ablation on hepatic phytol metabolism. Arch Biochem Biophys 2017; 635:17-26. [PMID: 29051070 DOI: 10.1016/j.abb.2017.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/10/2017] [Accepted: 10/14/2017] [Indexed: 12/19/2022]
Abstract
While prior studies focusing on male mice suggest a role for sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x; DKO) on hepatic phytol metabolism, its role in females is unresolved. This issue was addressed using female and male wild-type (WT) and DKO mice fed a phytoestrogen-free diet without or with 0.5% phytol. GC/MS showed that hepatic: i) phytol was absent and its branched-chain fatty acid (BCFA) metabolites were barely detectable in WT control-fed mice; ii) accumulation of phytol as well as its peroxisomal metabolite BCFAs (phytanic acid » pristanic and 2,3-pristenic acids) was increased by dietary phytol in WT females, but only slightly in WT males; iii) accumulation of phytol and BCFA was further increased by DKO in phytol-fed females, but much more markedly in males. Livers of phytol-fed WT female mice as well as phytol-fed DKO female and male mice also accumulated increased proportion of saturated straight-chain fatty acids (LCFA) at the expense of unsaturated LCFA. Liver phytol accumulation was not due to increased SCP-2 binding/transport of phytol since SCP-2 bound phytanic acid, but not its precursor phytol. Thus, the loss of Scp-2/Scp-x contributed to a sex-dependent hepatic accumulation of dietary phytol and BCFA.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Huan Huang
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843-4467, United States
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States.
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10
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Cai J, Du X, Wang C, Lin J, Du X. Identification of Potential Helicoverpa armigera (Lepidoptera: Noctuidae) Sterol Carrier Protein-2 Inhibitors Through High-Throughput Virtual Screening. JOURNAL OF ECONOMIC ENTOMOLOGY 2017; 110:1779-1784. [PMID: 28605511 DOI: 10.1093/jee/tox157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 06/07/2023]
Abstract
Helicoverpa armigera sterol carrier protein-2 (HaSCP-2) is a validated target for development of novel insecticides due to its divergent protein structure and function from the vertebrate SCP-2. HaSCP-2 is important for normal development and fertility in Helicoverpa armigera (Hübner). The discovery of chemical inhibitors of HaSCP-2 through a structure-based virtual screening is reported here. Bioassay indicated that H1 and H14 had inhibitory effect on the growth of H. armigera larvae. The results suggest that H1 and H14 are promising as useful lead compounds for further optimization and development of novel SCP-2-specific pesticides.
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Affiliation(s)
- Jun Cai
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Xinkai Du
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Changgao Wang
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Jianguo Lin
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Xin Du
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
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11
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Landrock D, Milligan S, Martin GG, McIntosh AL, Landrock KK, Schroeder F, Kier AB. Effect of Fabp1/Scp-2/Scp-x Ablation on Whole Body and Hepatic Phenotype of Phytol-Fed Male Mice. Lipids 2017; 52:385-397. [PMID: 28382456 PMCID: PMC5500168 DOI: 10.1007/s11745-017-4249-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/28/2017] [Indexed: 11/29/2022]
Abstract
Liver fatty acid binding protein (Fabp1) and sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) genes encode proteins that enhance hepatic uptake, cytosolic transport, and peroxisomal oxidation of toxic branched-chain fatty acids derived from dietary phytol. Since male wild-type (WT) mice express markedly higher levels of these proteins than females, the impact of ablating both genes (TKO) was examined in phytol-fed males. In WT males, high phytol diet alone had little impact on whole body weight and did not alter the proportion of lean tissue mass (LTM) versus fat tissue mass (FTM). TKO conferred on dietary phytol the ability to induce weight loss as well as reduce liver weight, FTM, and even more so LTM. Concomitantly TKO induced hepatic lipid accumulation, preferentially threefold increased phospholipid (PL) at the expense of decreased triacylglycerol (TG) and total cholesterol. Increased PL was associated with upregulation of membrane fatty acid transport/translocase proteins (FATP 2,4), cytosolic fatty acid/fatty acyl-CoA binding proteins (FABP2, ACBP), and the rate limiting enzyme in PL synthesis (Gpam). Decreased TG and cholesterol levels were not attributable to altered levels in respective synthetic enzymes or nuclear receptors. These data suggest that the higher level of Fabp1 and Scp2/Scpx gene products in WT males was protective against deleterious effects of dietary phytol, but TKO significantly exacerbated phytol effects in males.
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Affiliation(s)
- Danilo Landrock
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Sherrelle Milligan
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Gregory G Martin
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Avery L McIntosh
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Kerstin K Landrock
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA.
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12
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Storey SM, Huang H, McIntosh AL, Martin GG, Kier AB, Schroeder F. Impact of Fabp1/Scp-2/Scp-x gene ablation (TKO) on hepatic phytol metabolism in mice. J Lipid Res 2017; 58:1153-1165. [PMID: 28411199 DOI: 10.1194/jlr.m075457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/07/2017] [Indexed: 01/19/2023] Open
Abstract
Studies in vitro have suggested that both sterol carrier protein-2/sterol carrier protein-x (Scp-2/Scp-x) and liver fatty acid binding protein [Fabp1 (L-FABP)] gene products facilitate hepatic uptake and metabolism of lipotoxic dietary phytol. However, interpretation of physiological function in mice singly gene ablated in the Scp-2/Scp-x has been complicated by concomitant upregulation of FABP1. The work presented herein provides several novel insights: i) An 8-anilino-1-naphthalenesulfonic acid displacement assay showed that neither SCP-2 nor L-FABP bound phytol, but both had high affinity for its metabolite, phytanic acid; ii) GC-MS studies with phytol-fed WT and Fabp1/Scp-2/SCP-x gene ablated [triple KO (TKO)] mice showed that TKO exacerbated hepatic accumulation of phytol metabolites in vivo in females and less so in males. Concomitantly, dietary phytol increased hepatic levels of total long-chain fatty acids (LCFAs) in both male and female WT and TKO mice. Moreover, in both WT and TKO female mice, dietary phytol increased hepatic ratios of saturated/unsaturated and polyunsaturated/monounsaturated LCFAs, while decreasing the peroxidizability index. However, in male mice, dietary phytol selectively increased the saturated/unsaturated ratio only in TKO mice, while decreasing the peroxidizability index in both WT and TKO mice. These findings suggested that: 1) SCP-2 and FABP1 both facilitated phytol metabolism after its conversion to phytanic acid; and 2) SCP-2/SCP-x had a greater impact on hepatic phytol metabolism than FABP1.
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Affiliation(s)
- Stephen M Storey
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Huan Huang
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Avery L McIntosh
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Gregory G Martin
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Ann B Kier
- Pathobiology, Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Friedhelm Schroeder
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
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13
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Milligan S, Martin GG, Landrock D, McIntosh AL, Mackie JT, Schroeder F, Kier AB. Impact of dietary phytol on lipid metabolism in SCP2/SCPX/L-FABP null mice. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:291-304. [PMID: 27940000 PMCID: PMC5266609 DOI: 10.1016/j.bbalip.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/15/2016] [Accepted: 12/04/2016] [Indexed: 12/20/2022]
Abstract
In vitro studies suggest that liver fatty acid binding protein (L-FABP) and sterol carrier protein-2/sterol carrier protein-x (SCP2/SCPx) gene products facilitate uptake and metabolism and detoxification of dietary-derived phytol in mammals. However, concomitant upregulation of L-FABP in SCP2/SCPx null mice complicates interpretation of their physiological phenotype. Therefore, the impact of ablating both the L-FABP gene and SCP2/SCPx gene (L-FABP/SCP2/SCPx null or TKO) was examined in phytol-fed female wild-type (WT) and TKO mice. TKO increased hepatic total lipid accumulation, primarily phospholipid, by mechanisms involving increased hepatic levels of proteins in the phospholipid synthetic pathway. Concomitantly, TKO reduced expression of proteins in targeting fatty acids towards the triacylglycerol synthetic pathway. Increased hepatic lipid accumulation was not associated with any concomitant upregulation of membrane fatty acid transport/translocase proteins involved in fatty acid uptake (FATP2, FATP4, FATP5 or GOT) or cytosolic proteins involved in fatty acid intracellular targeting (ACBP). In addition, TKO exacerbated dietary phytol-induced whole body weight loss, especially lean tissue mass. Since individually ablating SCPx or SCP2/SCPx elicited concomitant upregulation of L-FABP, these findings with TKO mice help to resolve the contributions of SCP2/SCPx gene ablation on dietary phytol-induced whole body and hepatic lipid phenotype independent of concomitant upregulation of L-FABP.
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Affiliation(s)
- Sherrelle Milligan
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Gregory G Martin
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Danilo Landrock
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Avery L McIntosh
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - John T Mackie
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA.
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14
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Martin GG, Landrock D, Chung S, Dangott LJ, Seeger DR, Murphy EJ, Golovko MY, Kier AB, Schroeder F. Fabp1 gene ablation inhibits high-fat diet-induced increase in brain endocannabinoids. J Neurochem 2017; 140:294-306. [PMID: 27861894 PMCID: PMC5225076 DOI: 10.1111/jnc.13890] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 01/03/2023]
Abstract
The endocannabinoid system shifts energy balance toward storage and fat accumulation, especially in the context of diet-induced obesity. Relatively little is known about factors outside the central nervous system that may mediate the effect of high-fat diet (HFD) on brain endocannabinoid levels. One candidate is the liver fatty acid binding protein (FABP1), a cytosolic protein highly prevalent in liver, but not detected in brain, which facilitates hepatic clearance of fatty acids. The impact of Fabp1 gene ablation (LKO) on the effect of high-fat diet (HFD) on brain and plasma endocannabinoid levels was examined and data expressed for each parameter as the ratio of high-fat diet/control diet. In male wild-type mice, HFD markedly increased brain N-acylethanolamides, but not 2-monoacylglycerols. LKO blocked these effects of HFD in male mice. In female wild-type mice, HFD slightly decreased or did not alter these endocannabinoids as compared with male wild type. LKO did not block the HFD effects in female mice. The HFD-induced increase in brain arachidonic acid-derived arachidonoylethanolamide in males correlated with increased brain-free and total arachidonic acid. The ability of LKO to block the HFD-induced increase in brain arachidonoylethanolamide correlated with reduced ability of HFD to increase brain-free and total arachidonic acid in males. In females, brain-free and total arachidonic acid levels were much less affected by either HFD or LKO in the context of HFD. These data showed that LKO markedly diminished the impact of HFD on brain endocannabinoid levels, especially in male mice.
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Affiliation(s)
- Gregory G. Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Sarah Chung
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Lawrence J. Dangott
- Protein Chemistry Laboratory, Texas A&M University, College Station, TX 77843-2128
| | - Drew R. Seeger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Eric J. Murphy
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Mikhail Y. Golovko
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Ann B. Kier
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
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15
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Martin GG, Chung S, Landrock D, Landrock KK, Dangott LJ, Peng X, Kaczocha M, Murphy EJ, Kier AB, Schroeder F. Female Mice are Resistant to Fabp1 Gene Ablation-Induced Alterations in Brain Endocannabinoid Levels. Lipids 2016; 51:1007-20. [PMID: 27450559 PMCID: PMC5418128 DOI: 10.1007/s11745-016-4175-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022]
Abstract
Although liver fatty acid binding protein (FABP1, L-FABP) is not detectable in the brain, Fabp1 gene ablation (LKO) markedly increases endocannabinoids (EC) in brains of male mice. Since the brain EC system of females differs significantly from that of males, it was important to determine if LKO differently impacted the brain EC system. LKO did not alter brain levels of arachidonic acid (ARA)-containing EC, i.e. arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG), but decreased non-ARA-containing N-acylethanolamides (OEA, PEA) and 2-oleoylglycerol (2-OG) that potentiate the actions of AEA and 2-AG. These changes in brain potentiating EC levels were not associated with: (1) a net decrease in levels of brain membrane proteins associated with fatty acid uptake and EC synthesis; (2) a net increase in brain protein levels of cytosolic EC chaperones and enzymes in EC degradation; or (3) increased brain protein levels of EC receptors (CB1, TRVP1). Instead, the reduced or opposite responsiveness of female brain EC levels to loss of FABP1 (LKO) correlated with intrinsically lower FABP1 level in livers of WT females than males. These data show that female mouse brain endocannabinoid levels were unchanged (AEA, 2-AG) or decreased (OEA, PEA, 2-OG) by complete loss of FABP1 (LKO).
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, 4466 TAMU, College Station, TX, 77843-4466, USA
| | - Sarah Chung
- Department of Pathobiology, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University, 4466 TAMU, College Station, TX, 77843-4466, USA
| | - Lawrence J Dangott
- Protein Chemistry Laboratory, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Xiaoxue Peng
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Eric J Murphy
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202-9037, USA
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, 4466 TAMU, College Station, TX, 77843-4466, USA.
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16
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Singarapu KK, Ahuja A, Potula PR, Ummanni R. Solution Nuclear Magnetic Resonance Studies of Sterol Carrier Protein 2 Like 2 (SCP2L2) Reveal the Insecticide Specific Structural Characteristics of SCP2 Proteins in Aedes aegypti Mosquitoes. Biochemistry 2016; 55:4919-27. [DOI: 10.1021/acs.biochem.6b00322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Kiran Kumar Singarapu
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Ashish Ahuja
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Purushotam Reddy Potula
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Ramesh Ummanni
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
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17
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Martin GG, Chung S, Landrock D, Landrock KK, Huang H, Dangott LJ, Peng X, Kaczocha M, Seeger DR, Murphy EJ, Golovko MY, Kier AB, Schroeder F. FABP-1 gene ablation impacts brain endocannabinoid system in male mice. J Neurochem 2016; 138:407-22. [PMID: 27167970 PMCID: PMC4961623 DOI: 10.1111/jnc.13664] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 04/14/2016] [Accepted: 04/26/2016] [Indexed: 12/15/2022]
Abstract
Liver fatty acid-binding protein (FABP1, L-FABP) has high affinity for and enhances uptake of arachidonic acid (ARA, C20:4, n-6) which, when esterified to phospholipids, is the requisite precursor for synthesis of endocannabinoids (EC) such as arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG). The brain derives most of its ARA from plasma, taking up ARA and transporting it intracellularly via cytosolic fatty acid-binding proteins (FABPs 3,5, and 7) localized within the brain. In contrast, the much more prevalent cytosolic FABP1 is not detectable in the brain but is instead highly expressed in the liver. Therefore, the possibility that FABP1 outside the central nervous system may regulate brain AEA and 2-AG was examined in wild-type (WT) and FABP1 null (LKO) male mice. LKO increased brain levels of AA-containing EC (AEA, 2-AG), correlating with increased free and total ARA in brain and serum. LKO also increased brain levels of non-ARA that contain potentiating endocannabinoids (EC*) such as oleoyl ethanolamide (OEA), PEA, 2-OG, and 2-PG. Concomitantly, LKO decreased serum total ARA-containing EC, but not non-ARA endocannabinoids. LKO did not elicit these changes in the brain EC and EC* as a result of compensatory up-regulation of brain protein levels of enzymes in EC synthesis (NAPEPLD, DAGLα) or cytosolic EC chaperone proteins (FABPs 3, 5, 7, SCP-2, HSP70), or cannabinoid receptors (CB1, TRVP1). These data show for the first time that the non-CNS fatty acid-binding protein FABP1 markedly affected brain levels of both ARA-containing endocannabinoids (AEA, 2-AG) as well as their non-ARA potentiating endocannabinoids. Fatty acid-binding protein-1 (FABP-1) is not detectable in brain but instead is highly expressed in liver. The possibility that FABP1 outside the central nervous system may regulate brain endocannabinoids arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) was examined in wild-type (WT) and FABP-1 null (LKO) male mice. LKO increased brain levels of arachidonic acid-containing endocannabinoids (AEA, 2-AG), correlating with increased free and total arachidonic acid in brain and serum. Read the Editorial Highlight for this article on page 371.
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Affiliation(s)
- Gregory G. Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
| | - Sarah Chung
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Kerstin K. Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Huan Huang
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
| | - Lawrence J. Dangott
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Xiaoxue Peng
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY 11794
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY 11794
| | - Drew R. Seeger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Eric J. Murphy
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Mikhail Y. Golovko
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037 USA
| | - Ann B. Kier
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
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18
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Wang J, Bie J, Ghosh S. Intracellular cholesterol transport proteins enhance hydrolysis of HDL-CEs and facilitate elimination of cholesterol into bile. J Lipid Res 2016; 57:1712-9. [PMID: 27381048 DOI: 10.1194/jlr.m069682] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
While HDL-associated unesterified or free cholesterol (FC) is thought to be rapidly secreted into the bile, the fate of HDL-associated cholesteryl esters (HDL-CEs) that represent >80% of HDL-cholesterol, is only beginning to be understood. In the present study, we examined the hypothesis that intracellular cholesterol transport proteins [sterol carrier protein 2 (SCP2) and fatty acid binding protein-1 (FABP1)] not only facilitate CE hydrolase-mediated hydrolysis of HDL-CEs, but also enhance elimination of cholesterol into bile. Adenovirus-mediated overexpression of FABP1 or SCP2 in primary hepatocytes significantly increased hydrolysis of HDL-[(3)H]CE, reduced resecretion of HDL-CE-derived FC as nascent HDL, and increased its secretion as bile acids. Consistently, the flux of [(3)H]cholesterol from HDL-[(3)H]CE to biliary bile acids was increased by overexpression of SCP2 or FABP1 in vivo and reduced in SCP2(-/-) mice. Increased flux of HDL-[(3)H]CE to biliary FC was noted with FABP1 overexpression and in SCP2(-/-) mice that have increased FABP1 expression. Lack of a significant decrease in the flux of HDL-[(3)H]CE to biliary FC or bile acids in FABP1(-/-) mice indicates the likely compensation of its function by an as yet unidentified mechanism. Taken together, these studies demonstrate that FABP1 and SCP2 facilitate the preferential movement of HDL-CEs to bile for final elimination.
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Affiliation(s)
- Jing Wang
- Department of Internal Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298
| | - Jinghua Bie
- Department of Internal Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298
| | - Shobha Ghosh
- Department of Internal Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298
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19
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Ijssennagger N, Janssen AWF, Milona A, Ramos Pittol JM, Hollman DAA, Mokry M, Betzel B, Berends FJ, Janssen IM, van Mil SWC, Kersten S. Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid. J Hepatol 2016; 64:1158-1166. [PMID: 26812075 DOI: 10.1016/j.jhep.2016.01.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND & AIMS The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies demonstrated that FXR activation by OCA alters hepatic expression of many genes. However, no data are available on the effects of OCA in the human liver. Here we generated gene expression profiles in human precision cut liver slices (hPCLS) after treatment with OCA. METHODS hPCLS were incubated with OCA for 24 h. Wild-type or FXR(-/-) mice received OCA or vehicle by oral gavage for 7 days. RESULTS Transcriptomic analysis showed that well-known FXR target genes, including NR0B2 (SHP), ABCB11 (BSEP), SLC51A (OSTα) and SLC51B (OSTβ), and ABCB4 (MDR3) are regulated by OCA in hPCLS. Ingenuity pathway analysis confirmed that 'FXR/RXR activation' is the most significantly changed pathway upon OCA treatment. Comparison of gene expression profiles in hPCLS and mouse livers identified 18 common potential FXR targets. ChIP-sequencing in mouse liver confirmed FXR binding to IR1 sequences of Akap13, Cgnl1, Dyrk3, Pdia5, Ppp1r3b and Tbx6. CONCLUSIONS Our study shows that hPCLS respond to OCA treatment by upregulating well-known FXR target genes, demonstrating its suitability to study FXR-mediated gene regulation. We identified six novel bona-fide FXR target genes in both mouse and human liver. Finally, we discuss a possible explanation for changes in high or low density lipoprotein observed in NASH and primary biliary cholangitis patients treated with OCA based on the genomic expression profile in hPCLS.
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Affiliation(s)
- Noortje Ijssennagger
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Aafke W F Janssen
- Nutrition, Metabolism & Genomics Group, Division of Human Nutrition, Wageningen University, 6703 HD Wageningen, The Netherlands
| | - Alexandra Milona
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - José M Ramos Pittol
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Danielle A A Hollman
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Michal Mokry
- Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Bark Betzel
- Department of Surgery, Rijnstate Hospital, 6815 AD Arnhem, The Netherlands
| | - Frits J Berends
- Department of Surgery, Rijnstate Hospital, 6815 AD Arnhem, The Netherlands
| | - Ignace M Janssen
- Department of Surgery, Rijnstate Hospital, 6815 AD Arnhem, The Netherlands
| | - Saskia W C van Mil
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Sander Kersten
- Nutrition, Metabolism & Genomics Group, Division of Human Nutrition, Wageningen University, 6703 HD Wageningen, The Netherlands
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20
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Jouffe C, Gobet C, Martin E, Métairon S, Morin-Rivron D, Masoodi M, Gachon F. Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism. Sci Rep 2016; 6:24631. [PMID: 27097688 PMCID: PMC4838911 DOI: 10.1038/srep24631] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/29/2016] [Indexed: 01/22/2023] Open
Abstract
Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape.
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Affiliation(s)
- Céline Jouffe
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, CH-1011, Switzerland.,Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Cédric Gobet
- Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Eva Martin
- Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Sylviane Métairon
- Functional Genomic, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Delphine Morin-Rivron
- Department of Gastro-Intestinal Health &Microbiome, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Mojgan Masoodi
- Department of Gastro-Intestinal Health &Microbiome, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland.,Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Frédéric Gachon
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, CH-1011, Switzerland.,Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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21
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Freedman AH, Schweizer RM, Ortega-Del Vecchyo D, Han E, Davis BW, Gronau I, Silva PM, Galaverni M, Fan Z, Marx P, Lorente-Galdos B, Ramirez O, Hormozdiari F, Alkan C, Vilà C, Squire K, Geffen E, Kusak J, Boyko AR, Parker HG, Lee C, Tadigotla V, Siepel A, Bustamante CD, Harkins TT, Nelson SF, Marques-Bonet T, Ostrander EA, Wayne RK, Novembre J. Demographically-Based Evaluation of Genomic Regions under Selection in Domestic Dogs. PLoS Genet 2016; 12:e1005851. [PMID: 26943675 PMCID: PMC4778760 DOI: 10.1371/journal.pgen.1005851] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/18/2016] [Indexed: 12/31/2022] Open
Abstract
Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rd top hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers.
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Affiliation(s)
- Adam H. Freedman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Rena M. Schweizer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Diego Ortega-Del Vecchyo
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Eunjung Han
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Brian W. Davis
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ilan Gronau
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, United States of America
| | | | | | - Zhenxin Fan
- Key Laboratory of Bioresources and Ecoenvironment, Sichuan University, Chengdu, China
| | - Peter Marx
- Department of Measurement and Information Systems, Budapest University of Technology and Economics, Budapest, Hungary
| | - Belen Lorente-Galdos
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Oscar Ramirez
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Farhad Hormozdiari
- Department of Computer Science, University of California, Los Angeles, Los Angeles, California, United States of America
| | | | - Carles Vilà
- Estación Biológia de Doñana EBD-CSIC, Sevilla, Spain
| | - Kevin Squire
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Eli Geffen
- Department of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Josip Kusak
- Department of Biology, University of Zagreb, Zagreb, Croatia
| | - Adam R. Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
| | - Heidi G. Parker
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Clarence Lee
- Life Technologies, Foster City, California, United States of America
| | - Vasisht Tadigotla
- Life Technologies, Foster City, California, United States of America
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | | | | | - Stanley F. Nelson
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Tomas Marques-Bonet
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
- Centro Nacional de Analisis Genomico (CNAG/PCB), Baldiri Reixach 4–8, Barcelona, Spain
| | - Elaine A. Ostrander
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert K. Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - John Novembre
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
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22
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Long B, Muhamad R, Yan G, Yu J, Fan Q, Wang Z, Li X, Purnomoadi A, Achmadi J, Yan X. Quantitative proteomics analysis reveals glutamine deprivation activates fatty acid β-oxidation pathway in HepG2 cells. Amino Acids 2016; 48:1297-307. [PMID: 26837383 DOI: 10.1007/s00726-016-2182-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 01/19/2016] [Indexed: 02/06/2023]
Abstract
Glutamine, a multifunctional amino acid, functions in nutrient metabolism, energy balance, apoptosis, and cell proliferation. Lipid is an important nutrient and controls a broad range of physiological processes. Previous studies have demonstrated that glutamine can affect lipolysis and lipogenesis, but the effect of glutamine on the detailed lipid metabolism remains incompletely understood. Here, we applied the quantitative proteomics approach to estimate the relative abundance of proteins in HepG2 cells treated by glutamine deprivation. The results showed that there were 212 differentially abundant proteins in response to glutamine deprivation, including 150 significantly increased proteins and 62 significantly decreased proteins. Interestingly, functional classification showed that 43 differentially abundant proteins were related to lipid metabolism. Further bioinformatics analysis and western blotting validation revealed that lipid accumulation may be affected by β-oxidation of fatty acid induced by glutamine deprivation in HepG2 cells. Together, our results may provide the potential for regulating lipid metabolism by glutamine in animal production and human nutrition. The MS data have been deposited to the ProteomeXchange Consortium with identifier PXD003387.
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Affiliation(s)
- Baisheng Long
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Rodiallah Muhamad
- Faculty of Animal and Agricultural Sciences, Diponegoro University, Tembalang Campus, Semarang, 50275, Central Java, Indonesia
| | - Guokai Yan
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Jie Yu
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Qiwen Fan
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Zhichang Wang
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Xiuzhi Li
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Agung Purnomoadi
- Faculty of Animal and Agricultural Sciences, Diponegoro University, Tembalang Campus, Semarang, 50275, Central Java, Indonesia
| | - Joelal Achmadi
- Faculty of Animal and Agricultural Sciences, Diponegoro University, Tembalang Campus, Semarang, 50275, Central Java, Indonesia
| | - Xianghua Yan
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. .,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China.
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23
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Martin GG, Landrock D, Landrock KK, Howles PN, Atshaves BP, Kier AB, Schroeder F. Relative contributions of L-FABP, SCP-2/SCP-x, or both to hepatic biliary phenotype of female mice. Arch Biochem Biophys 2015; 588:25-32. [PMID: 26541319 PMCID: PMC4683591 DOI: 10.1016/j.abb.2015.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/20/2015] [Accepted: 10/28/2015] [Indexed: 01/01/2023]
Abstract
Both sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) and liver fatty acid binding protein (L-FABP) have been proposed to function in hepatobiliary bile acid metabolism/accumulation. To begin to address this issue, the impact of ablating L-FABP (LKO) or SCP-2/SCP-x (DKO) individually or both together (TKO) was examined in female mice. Biliary bile acid levels were decreased in LKO, DKO, and TKO mice; however, hepatic bile acid concentration was decreased in LKO mice only. In contrast, biliary phospholipid level was decreased only in TKO mice, while biliary cholesterol levels were unaltered regardless of phenotype. The loss of either or both genes increased hepatic expression of the major bile acid synthetic enzymes (CYP7A1 and/or CYP27A1). Loss of L-FABP and/or SCP-2/SCP-x genes significantly altered the molecular composition of biliary bile acids, but not the proportion of conjugated/unconjugated bile acids or overall bile acid hydrophobicity index. These data suggested that L-FABP was more important in hepatic retention of bile acids, while SCP-2/SCP-x more broadly affected biliary bile acid and phospholipid levels.
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
| | - Philip N Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Barbara P Atshaves
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA.
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24
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Klipsic D, Landrock D, Martin GG, McIntosh AL, Landrock KK, Mackie JT, Schroeder F, Kier AB. Impact of SCP-2/SCP-x gene ablation and dietary cholesterol on hepatic lipid accumulation. Am J Physiol Gastrointest Liver Physiol 2015; 309:G387-99. [PMID: 26113298 PMCID: PMC4556946 DOI: 10.1152/ajpgi.00460.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/22/2015] [Indexed: 01/31/2023]
Abstract
While a high-cholesterol diet induces hepatic steatosis, the role of intracellular sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) proteins is unknown. We hypothesized that ablating SCP-2/SCP-x [double knockout (DKO)] would impact hepatic lipids (cholesterol and cholesteryl ester), especially in high-cholesterol-fed mice. DKO did not alter food consumption, and body weight (BW) gain decreased especially in females, concomitant with hepatic steatosis in females and less so in males. DKO-induced steatosis in control-fed wild-type (WT) mice was associated with 1) loss of SCP-2; 2) upregulation of liver fatty acid binding protein (L-FABP); 3) increased mRNA and/or protein levels of sterol regulatory element binding proteins (SREBP1 and SREBP2) as well as increased expression of target genes of cholesterol synthesis (Hmgcs1 and Hmgcr) and fatty acid synthesis (Acc1 and Fas); and 4) cholesteryl ester accumulation was also associated with increased acyl-CoA cholesterol acyltransferase-2 (ACAT2) in males. DKO exacerbated the high-cholesterol diet-induced hepatic cholesterol and glyceride accumulation, without further increasing SREBP1, SREBP2, or target genes. This exacerbation was associated both with loss of SCP-2 and concomitant downregulation of Ceh/Hsl, apolipoprotein B (ApoB), MTP, and/or L-FABP protein expression. DKO diminished the ability to secrete excess cholesterol into bile and oxidize cholesterol to bile acid for biliary excretion, especially in females. This suggested that SCP-2/SCP-x affects cholesterol transport to particular intracellular compartments, with ablation resulting in less to the endoplasmic reticulum for SREBP regulation, making more available for cholesteryl ester synthesis, for cholesteryl-ester storage in lipid droplets, and for bile salt synthesis and/or secretion. These alterations are significant findings, since they affect key processes in regulation of sterol metabolism.
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Affiliation(s)
- Devon Klipsic
- Department of Pathobiology, Texas A&M University, College Station, Texas; and
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, Texas; and
| | - Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - John T Mackie
- Department of Pathobiology, Texas A&M University, College Station, Texas; and
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, Texas; and
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25
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Martin GG, Atshaves BP, Landrock KK, Landrock D, Schroeder F, Kier AB. Loss of L-FABP, SCP-2/SCP-x, or both induces hepatic lipid accumulation in female mice. Arch Biochem Biophys 2015; 580:41-9. [PMID: 26116377 DOI: 10.1016/j.abb.2015.06.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Revised: 06/08/2015] [Accepted: 06/17/2015] [Indexed: 02/06/2023]
Abstract
Although roles for both sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) and liver fatty acid binding protein (L-FABP) have been proposed in hepatic lipid accumulation, individually ablating these genes has been complicated by concomitant alterations in the other gene product(s). For example, ablating SCP2/SCP-x induces upregulation of L-FABP in female mice. Therefore, the impact of ablating SCP-2/SCP-x (DKO) or L-FABP (LKO) individually or both together (TKO) was examined in female mice. Loss of SCP-2/SCP-x (DKO, TKO) more so than loss of L-FABP alone (LKO) increased hepatic total lipid and total cholesterol content, especially cholesteryl ester. Hepatic accumulation of nonesterified long chain fatty acids (LCFA) and phospholipids occurred only in DKO and TKO mice. Loss of SCP-2/SCP-x (DKO, TKO) increased serum total lipid primarily by increasing triglycerides. Altered hepatic level of proteins involved in cholesterol uptake, efflux, and/or secretion was observed, but did not compensate for the loss of L-FABP, SCP-2/SCP-x or both. However, synergistic responses were not seen with the combinatorial knock out animals-suggesting that inhibiting SCP-2/SCP-x is more correlative with hepatic dysfunction than L-FABP. The DKO- and TKO-induced hepatic accumulation of cholesterol and long chain fatty acids shared significant phenotypic similarities with non-alcoholic fatty liver disease (NAFLD).
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, United States
| | - Barbara P Atshaves
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
| | - Kerstin K Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, United States
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, United States
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, United States
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, United States.
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26
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Sahadevan S, Tholen E, Große-Brinkhaus C, Schellander K, Tesfaye D, Hofmann-Apitius M, Cinar MU, Gunawan A, Hölker M, Neuhoff C. Identification of gene co-expression clusters in liver tissues from multiple porcine populations with high and low backfat androstenone phenotype. BMC Genet 2015; 16:21. [PMID: 25884519 PMCID: PMC4365963 DOI: 10.1186/s12863-014-0158-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/18/2014] [Indexed: 11/26/2022] Open
Abstract
Background Boar taint is principally caused by accumulation of androstenone and skatole in adipose tissues. Studies have shown high heritability estimates for androstenone whereas skatole production is mainly dependent on nutritional factors. Androstenone is a lipophilic steroid mainly metabolized in liver. Majority of the studies on hepatic androstenone metabolism focus only on a single breed and very few studies account for population similarities/differences in gene expression patterns. In this work, we concentrated on population similarities in gene expression to identify the common genes involved in hepatic androstenone metabolism of multiple pig populations. Based on androstenone measurements, publicly available gene expression datasets from three porcine populations were compiled into either low or high androstenone dataset. Gene expression correlation coefficients from these datasets were converted to rank ratios and joint probabilities of these rank ratios were used to generate dataset specific co-expression clusters. Finally, these networks were clustered using a graph clustering technique. Results Cluster analysis identified a number of statistically significant co-expression clusters in the dataset. Further enrichment analysis of these clusters showed that one of the clusters from low androstenone dataset was highly enriched for xenobiotic, drug, cholesterol and lipid metabolism and cytochrome P450 associated metabolism of drugs and xenobiotics. Literature references revealed that a number of genes in this cluster were involved in phase I and phase II metabolism. Physical and functional similarity assessment showed that the members of this cluster were dispersed across multiple clusters in high androstenone dataset, possibly indicating a weak co-expression of these genes in high androstenone dataset. Conclusions Based on these results we hypothesize that majority of the genes in this cluster forms a signature co-expression cluster in low androstenone dataset in our experiment and that majority of the members of this cluster might be responsible for hepatic androstenone metabolism across all the three populations used in our study. We propose these results as a background work towards understanding breed similarities in hepatic androstenone metabolism. Additional large scale experiments using data from multiple porcine breeds are necessary to validate these findings. Electronic supplementary material The online version of this article (doi:10.1186/s12863-014-0158-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sudeep Sahadevan
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany. .,Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, 53754, Germany.
| | - Ernst Tholen
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany.
| | | | - Karl Schellander
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany.
| | - Dawit Tesfaye
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany.
| | - Martin Hofmann-Apitius
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, 53754, Germany.
| | - Mehmet Ulas Cinar
- Department of Animal Science, Faculty of Agriculture, Erciyes University, Kayseri, Turkey.
| | - Asep Gunawan
- Department of Animal Production and Technology, Bogor Agricultural University, Bogor, Indonesia.
| | - Michael Hölker
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany.
| | - Christiane Neuhoff
- Institute of Animal Science, University of Bonn, Endenicher Alle, Bonn, 53115, Germany.
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27
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Martin GG, Atshaves BP, Landrock KK, Landrock D, Storey SM, Howles PN, Kier AB, Schroeder F. Ablating L-FABP in SCP-2/SCP-x null mice impairs bile acid metabolism and biliary HDL-cholesterol secretion. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1130-43. [PMID: 25277800 PMCID: PMC4254959 DOI: 10.1152/ajpgi.00209.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/28/2014] [Indexed: 01/31/2023]
Abstract
On the basis of their abilities to bind bile acids and/or cholesterol, the physiological role(s) of liver fatty acid-binding protein (L-FABP) and sterol carrier protein (SCP) 2/SCP-x (SCP-2/SCP-x) gene products in biliary bile acid and cholesterol formation was examined in gene-ablated male mice. L-FABP (LKO) or L-FABP/SCP-2/SCP-x [triple-knockout (TKO)] ablation markedly decreased hepatic bile acid concentration, while SCP-2/SCP-x [double-knockout (DKO)] ablation alone had no effect. In contrast, LKO increased biliary bile acid, while DKO and TKO had no effect on biliary bile acid levels. LKO and DKO also altered biliary bile acid composition to increase bile acid hydrophobicity. Furthermore, LKO and TKO decreased hepatic uptake and biliary secretion of high-density lipoprotein (HDL)-derived 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol), while DKO alone had no effect. Finally, LKO and, to a lesser extent, DKO decreased most indexes contributing to cholesterol solubility in biliary bile. These results suggest different, but complementary, roles for L-FABP and SCP-2/SCP-x in biliary bile acid and cholesterol formation. L-FABP appears to function more in hepatic retention of bile acids as well as hepatic uptake and biliary secretion of HDL-cholesterol. Conversely, SCP-2/SCP-x may function more in formation and biliary secretion of bile acid, with less impact on hepatic uptake or biliary secretion of HDL-cholesterol.
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas
| | - Barbara P Atshaves
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Kerstin K Landrock
- Department of Pathobiology, Texas A & M University, College Station, Texas; and
| | - Danilo Landrock
- Department of Pathobiology, Texas A & M University, College Station, Texas; and
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas
| | - Philip N Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Ann B Kier
- Department of Pathobiology, Texas A & M University, College Station, Texas; and
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas;
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28
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Cerqueira DM, Tran U, Romaker D, Abreu JG, Wessely O. Sterol carrier protein 2 regulates proximal tubule size in the Xenopus pronephric kidney by modulating lipid rafts. Dev Biol 2014; 394:54-64. [PMID: 25127994 DOI: 10.1016/j.ydbio.2014.07.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 05/29/2014] [Accepted: 07/30/2014] [Indexed: 11/29/2022]
Abstract
The kidney is a homeostatic organ required for waste excretion and reabsorption of water, salts and other macromolecules. To this end, a complex series of developmental steps ensures the formation of a correctly patterned and properly proportioned organ. While previous studies have mainly focused on the individual signaling pathways, the formation of higher order receptor complexes in lipid rafts is an equally important aspect. These membrane platforms are characterized by differences in local lipid and protein compositions. Indeed, the cells in the Xenopus pronephric kidney were positive for the lipid raft markers ganglioside GM1 and Caveolin-1. To specifically interfere with lipid raft function in vivo, we focused on the Sterol Carrier Protein 2 (scp2), a multifunctional protein that is an important player in remodeling lipid raft composition. In Xenopus, scp2 mRNA was strongly expressed in differentiated epithelial structures of the pronephric kidney. Knockdown of scp2 did not interfere with the patterning of the kidney along its proximo-distal axis, but dramatically decreased the size of the kidney, in particular the proximal tubules. This phenotype was accompanied by a reduction of lipid rafts, but was independent of the peroxisomal or transcriptional activities of scp2. Finally, disrupting lipid micro-domains by inhibiting cholesterol synthesis using Mevinolin phenocopied the defects seen in scp2 morphants. Together these data underscore the importance for localized signaling platforms in the proper formation of the Xenopus kidney.
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Affiliation(s)
- Débora M Cerqueira
- Cleveland Clinic Foundation, Lerner Research Institute, Department Cellular and Molecular Medicine, 9500 Euclid Avenue/NC10 Cleveland, OH 44195, USA; Universidade Federal do Rio de Janeiro, Instituto de Ciências Biomédicas-CCS, Av. Carlos Chagas Filho, 373 bloco F2 sala 15, Rio de Janeiro 21949-590, Brazil
| | - Uyen Tran
- Cleveland Clinic Foundation, Lerner Research Institute, Department Cellular and Molecular Medicine, 9500 Euclid Avenue/NC10 Cleveland, OH 44195, USA
| | - Daniel Romaker
- Cleveland Clinic Foundation, Lerner Research Institute, Department Cellular and Molecular Medicine, 9500 Euclid Avenue/NC10 Cleveland, OH 44195, USA
| | - José G Abreu
- Universidade Federal do Rio de Janeiro, Instituto de Ciências Biomédicas-CCS, Av. Carlos Chagas Filho, 373 bloco F2 sala 15, Rio de Janeiro 21949-590, Brazil
| | - Oliver Wessely
- Cleveland Clinic Foundation, Lerner Research Institute, Department Cellular and Molecular Medicine, 9500 Euclid Avenue/NC10 Cleveland, OH 44195, USA.
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29
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Chen C, Yang B, Zeng Z, Yang H, Liu C, Ren J, Huang L. Genetic dissection of blood lipid traits by integrating genome-wide association study and gene expression profiling in a porcine model. BMC Genomics 2013; 14:848. [PMID: 24299188 PMCID: PMC4046658 DOI: 10.1186/1471-2164-14-848] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 11/19/2013] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Serum concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) are highly heritable traits that are used clinically to evaluate risk for cardiovascular disease in humans. In this study, we applied a genome-wide association study (GWAS) in 1,075 pigs from two populations and gene expression studies on 497 liver samples to dissect the genetic basis of serum lipids in a pig model. RESULTS We totally identified 8, 5, 2 and 3 genomic loci harboring 109 SNPs that were significantly associated with LDL-C, TC, TG and the ratio of HDL-C/LDL-C in two experimental populations, respectively. In the F2 population, the most prominent SNP was identified at the SSC3: 124,769,847 bp where APOB is the well-known candidate gene. However, in the Sutai population, the most number of significant SNPs was identified at SSC2: 64.97-82.22 Mb where LDLR was identified as the candidate gene. Furthermore, we firstly reported 4 novel genomic loci in pigs harboring the LDL-C-associated SNPs. We also observed obvious population heterogeneity in the two tested populations. Through whole-genome gene expression analysis, we detected 718 trait-correlated expressions. Many of these transcripts correspond to candidate genes for blood lipids in humans. The GWAS mapped 120 cis-eQTLs and 523 trans-eQTLs for these transcripts. One gene encoding the transcript gnl|UG|Ssc#S35330332 stands out to be an important candidate gene for LDL-C by an integrative analysis of GWAS, eQTL and trait-associated expression. CONCLUSIONS We identified the genomic regions or candidate genes associated with blood lipids by an integrative analysis of GWAS, QTT and eQTL mapping in pigs. The findings would benefit the further identification of the causative genes for blood lipid traits in both pigs and humans.
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Affiliation(s)
- Congying Chen
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Bin Yang
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Zhijun Zeng
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Hui Yang
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Chenlong Liu
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Jun Ren
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
| | - Lusheng Huang
- Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, 330045 Nanchang, China
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30
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Quaternary structure of human, Drosophila melanogaster
and Caenorhabditis elegans
MFE-2 in solution from synchrotron small-angle X-ray scattering. FEBS Lett 2013; 587:305-10. [DOI: 10.1016/j.febslet.2012.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/22/2012] [Accepted: 12/14/2012] [Indexed: 11/22/2022]
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Du X, Ma H, Zhang X, Liu K, Peng J, Lan Q, Hong H. Characterization of the sterol carrier protein-x/sterol carrier protein-2 gene in the cotton bollworm, Helicoverpa armigera. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:1413-1423. [PMID: 22922458 DOI: 10.1016/j.jinsphys.2012.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Abstract
Cholesterol is a membrane component and the precursor of ecdysteroids in insects, but insects cannot synthesize cholesterol de novo. Therefore, cholesterol uptake and transportation during the feeding larval stages are critical processes in insects. The sterol carrier protein-2 domain (SCP-2) in sterol carrier proteins-x (SCP-x) has been speculated to be involved in intracellular cholesterol transfer and metabolism in vertebrates. However, a direct association between SCP-x gene expression, cholesterol absorption and development in lepidopteran insects is poorly understood. We identified the Helicoverpa armigera sterol carrier protein-x/2 (HaSCP-x/2) gene from the larval midgut cDNAs. The HaSCP-x/2 gene is well conserved during evolution and relatively divergent in heterogenetic species. Transcripts of HaSCP-x/2 were detected by qRT-PCR at the highest level in the midgut of H. armigera during the larval stages. Expression knockdown of HaSCP-x/2 transcripts via dsRNA interference resulted in delayed larval development and decreased adult fecundity. Sterol carrier protein-2 inhibitors were lethal to young larvae and decreased fertility in adults emerged from treated elder larvae in H. armigera. The results taken together suggest that HaSCPx/2 gene is important for normal development and fertility in H. armigera.
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Affiliation(s)
- Xin Du
- College of Life Sciences, Central China Normal University, 100 Luoyu Road, Wuhan, Hubei 430079, PR China
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Storey SM, McIntosh AL, Huang H, Martin GG, Landrock KK, Landrock D, Payne HR, Kier AB, Schroeder F. Loss of intracellular lipid binding proteins differentially impacts saturated fatty acid uptake and nuclear targeting in mouse hepatocytes. Am J Physiol Gastrointest Liver Physiol 2012; 303:G837-50. [PMID: 22859366 PMCID: PMC3469595 DOI: 10.1152/ajpgi.00489.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The liver expresses high levels of two proteins with high affinity for long-chain fatty acids (LCFAs): liver fatty acid binding protein (L-FABP) and sterol carrier protein-2 (SCP-2). Real-time confocal microscopy of cultured primary hepatocytes from gene-ablated (L-FABP, SCP-2/SCP-x, and L-FABP/SCP-2/SCP-x null) mice showed that the loss of L-FABP reduced cellular uptake of 12-N-methyl-(7-nitrobenz-2-oxa-1,3-diazo)-aminostearic acid (a fluorescent-saturated LCFA analog) by ∼50%. Importantly, nuclear targeting of the LCFA was enhanced when L-FABP was upregulated (SCP-2/SCP-x null) but was significantly reduced when L-FABP was ablated (L-FABP null), thus impacting LCFA nuclear targeting. These effects were not associated with a net decrease in expression of key membrane proteins involved in LCFA or glucose transport. Since hepatic LCFA uptake and metabolism are closely linked to glucose uptake, the effect of glucose on L-FABP-mediated LCFA uptake and nuclear targeting was examined. Increasing concentrations of glucose decreased cellular LCFA uptake and even more extensively decreased LCFA nuclear targeting. Loss of L-FABP exacerbated the decrease in LCFA nuclear targeting, while loss of SCP-2 reduced the glucose effect, resulting in enhanced LCFA nuclear targeting compared with control. Simply, ablation of L-FABP decreases LCFA uptake and even more extensively decreases its nuclear targeting.
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Affiliation(s)
- Stephen M. Storey
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
| | - Avery L. McIntosh
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
| | - Huan Huang
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
| | - Gregory G. Martin
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
| | - Kerstin K. Landrock
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
| | - Danilo Landrock
- 2Department of Pathobiology, Texas A & M University, College Station, Texas
| | - H. Ross Payne
- 2Department of Pathobiology, Texas A & M University, College Station, Texas
| | - Ann B. Kier
- 2Department of Pathobiology, Texas A & M University, College Station, Texas
| | - Friedhelm Schroeder
- 1Department of Physiology and Pharmacology, Texas A & M University, College Station, Texas; and
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Storey SM, McIntosh AL, Huang H, Landrock KK, Martin GG, Landrock D, Payne HR, Atshaves BP, Kier AB, Schroeder F. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes. Am J Physiol Gastrointest Liver Physiol 2012; 302:G824-39. [PMID: 22241858 PMCID: PMC3355564 DOI: 10.1152/ajpgi.00195.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 01/07/2012] [Indexed: 01/31/2023]
Abstract
A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2/SCP-x/L-FABP null mice and hepatocytes. Taken together, these results suggest that L-FABP, particularly in the absence of SCP-2, plays a significant role in HDL-mediated cholesterol uptake in cultured primary hepatocytes.
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Affiliation(s)
- Stephen M Storey
- Department of Physiology and Pharmacology, Texas Veterinary Medical Center, Texas A & M University, College Station, TX 77843-4466, USA
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McIntosh AL, Atshaves BP, Storey SM, Landrock KK, Landrock D, Martin GG, Kier AB, Schroeder F. Loss of liver FA binding protein significantly alters hepatocyte plasma membrane microdomains. J Lipid Res 2012; 53:467-480. [PMID: 22223861 PMCID: PMC3276470 DOI: 10.1194/jlr.m019919] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 12/21/2011] [Indexed: 12/13/2022] Open
Abstract
Although lipid-rich microdomains of hepatocyte plasma membranes serve as the major scaffolding regions for cholesterol transport proteins important in cholesterol disposition, little is known regarding intracellular factors regulating cholesterol distribution therein. On the basis of its ability to bind cholesterol and alter hepatic cholesterol accumulation, the cytosolic liver type FA binding protein (L-FABP) was hypothesized to be a candidate protein regulating these microdomains. Compared with wild-type hepatocyte plasma membranes, L-FABP gene ablation significantly increased the proportion of cholesterol-rich microdomains. Lack of L-FABP selectively increased cholesterol, phospholipid (especially phosphatidylcholine), and branched-chain FA accumulation in the cholesterol-rich microdomains. These cholesterol-rich microdomains are important, owing to enrichment therein of significant amounts of key transport proteins involved in uptake of cholesterol [SR-B1, ABCA-1, P-glycoprotein (P-gp), sterol carrier binding protein (SCP-2)], FA transport protein (FATP), and glucose transporters 1 and 2 (GLUT1, GLUT2) insulin receptor. L-FABP gene ablation enhanced the concentration of SCP-2, SR-B1, FATP4, and GLUT1 in the cholesterol-poor microdomains, with functional implications in HDL-mediated uptake and efflux of cholesterol. Thus L-FABP gene ablation significantly impacted the proportion of cholesterol-rich versus -poor microdomains in the hepatocyte plasma membrane and altered the distribution of lipids and proteins involved in cholesterol uptake therein.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Barbara P Atshaves
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University Texas Veterinary Medical Center, College Station, TX 77843; and.
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Barbhuiya MA, Sahasrabuddhe NA, Pinto SM, Muthusamy B, Singh TD, Nanjappa V, Keerthikumar S, Delanghe B, Harsha HC, Chaerkady R, Jalaj V, Gupta S, Shrivastav BR, Tiwari PK, Pandey A. Comprehensive proteomic analysis of human bile. Proteomics 2011; 11:4443-53. [PMID: 22114102 DOI: 10.1002/pmic.201100197] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 07/27/2011] [Accepted: 08/24/2011] [Indexed: 01/21/2023]
Abstract
Bile serves diverse functions from metabolism to transport. In addition to acids and salts, bile is composed of proteins secreted or shed by the hepatobiliary system. Although there have been previous efforts to catalog biliary proteins, an in-depth analysis of the bile proteome has not yet been reported. We carried out fractionation of non-cancerous bile samples using a multipronged approach (SDS-PAGE, SCX and OFFGEL) followed by MS analysis on an LTQ-Orbitrap Velos mass spectrometer using high resolution at both MS and MS/MS levels. We identified 2552 proteins - the largest number of proteins reported in human bile till date. To our knowledge, there are no previous studies employing high-resolution MS reporting a more detailed catalog of any body fluid proteome in a single study. We propose that extensive fractionation coupled to high-resolution MS can be used as a standard methodology for in-depth characterization of any body fluid. This catalog should serve as a baseline for the future studies aimed at discovering biomarkers from bile in gallbladder, hepatic, and biliary cancers.
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Affiliation(s)
- Mustafa A Barbhuiya
- Centre for Genomics, Molecular and Human Genetics, Jiwaji University, Gwalior, India
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Miller WL, Bose HS. Early steps in steroidogenesis: intracellular cholesterol trafficking. J Lipid Res 2011; 52:2111-2135. [PMID: 21976778 DOI: 10.1194/jlr.r016675] [Citation(s) in RCA: 361] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Steroid hormones are made from cholesterol, primarily derived from lipoproteins that enter cells via receptor-mediated endocytosis. In endo-lysosomes, cholesterol is released from cholesterol esters by lysosomal acid lipase (LAL; disordered in Wolman disease) and exported via Niemann-Pick type C (NPC) proteins (disordered in NPC disease). These diseases are characterized by accumulated cholesterol and cholesterol esters in most cell types. Mechanisms for trans-cytoplasmic cholesterol transport, membrane insertion, and retrieval from membranes are less clear. Cholesterol esters and "free" cholesterol are enzymatically interconverted in lipid droplets. Cholesterol transport to the cholesterol-poor outer mitochondrial membrane (OMM) appears to involve cholesterol transport proteins. Cytochrome P450scc (CYP11A1) then initiates steroidogenesis by converting cholesterol to pregnenolone on the inner mitochondrial membrane (IMM). Acute steroidogenic responses are regulated by cholesterol delivery from OMM to IMM, triggered by the steroidogenic acute regulatory protein (StAR). Chronic steroidogenic capacity is determined by CYP11A1 gene transcription. StAR mutations cause congenital lipoid adrenal hyperplasia, with absent steroidogenesis, potentially lethal salt loss, and 46,XY sex reversal. StAR mutations initially destroy most, but not all steroidogenesis; low levels of StAR-independent steroidogenesis are lost later due to cellular damage, explaining the clinical findings. Rare P450scc mutations cause a similar syndrome. This review addresses these early steps in steroid biosynthesis.
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Affiliation(s)
- Walter L Miller
- Department of Pediatrics, School of Medicine, University of California, San Francisco, CA 94143; UCSF Benioff Children's Hospital, San Francisco, CA 94143.
| | - Himangshu S Bose
- Department of Biochemistry, Mercer University School of Medicine, Savannah, GA 31404; and; Memorial University Medical Center, Savannah, GA 31404
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Xiao R, Power RF, Mallonee D, Crowdus C, Brennan KM, Ao T, Pierce JL, Dawson KA. A comparative transcriptomic study of vitamin E and an algae-based antioxidant as antioxidative agents: investigation of replacing vitamin E with the algae-based antioxidant in broiler diets. Poult Sci 2011; 90:136-46. [PMID: 21177453 DOI: 10.3382/ps.2010-01018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous study indicated that inclusion of an algae-based antioxidant as an antioxidative agent [EconomasE, Alltech, Nicholasville, KY; EcoE] significantly reduced the amount of vitamin E (VE) required in broiler diets without compromising performance and meat quality. To assess the mechanisms related to the VE-saving activity of EcoE, as well as other potential functions related to EcoE and VE supplementation, we analyzed gene expression profiles of breast muscle from broilers fed a control diet, the control diet + 50 IU of VE/kg, the control diet + 100 IU of VE/kg, or the control diet + 200 g of EcoE/ton. Evaluation of the serum antioxidant capacity indicated that dietary supplementation of either a high level of VE (50 or 100 IU of VE/kg) or EcoE significantly improved bird antioxidant status. Analysis of gene expression profiles indicated that expression of 542 genes of the breast muscle were altered (P < 0.05, fold change >1.2) by dietary treatments, of which a significant part were commonly regulated by EcoE and VE (especially the control diet + 50 IU of VE/kg). In addition to the process of cellular oxidation, gene ontology analysis indicated the involvement of EcoE and VE on cell morphology, skeletal and muscular system development and function, immune response, and multiple metabolic processes, including lipid, carbohydrate, and drug metabolism. Results of this experiment indicate that the biological roles of high VE, including its activity as an antioxidant, can be greatly mimicked at the transcriptional level by EcoE, and they suggest a relationship of functional redundancy between VE and EcoE in the broiler diets.
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Affiliation(s)
- R Xiao
- Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech, Nicholasville, KY 40356, USA.
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Cui Y, Li Z, Zhao E, Jia Y, Li D, Zhang J, Cui N. Overexpression of Sterol Carrier Protein 2 in patients with hereditary cholesterol gallstones. BMC Gastroenterol 2011; 11:10. [PMID: 21310066 PMCID: PMC3042972 DOI: 10.1186/1471-230x-11-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 02/10/2011] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Lithogenic bile is the major cause of cholesterol gallstone, but its pathogenesis is not well understood. The hypersecretion of biliary cholesterol is believed to be an important cause of lithogenic bile. Sterol Carrier Protein 2 (SCP2) participates in cholesterol trafficking and lipid metabolism in hepatocytes and may play a key role in cholesterol gallstone formation. METHODS 21 cholesterol gallstone genealogies were studied to investigate the expression of SCP2 gene in liver tissue of hereditary and non-hereditary cholesterol gallstone patients as well as non-gallstone patients. The mRNA expression of liver SCP2 in 28 hereditary patients, 30 non-hereditary cholesterol gallstone patients and 32 non-gallstone patients was measured by Reverse Transcription Polymerase Chain Reaction (RT-PCR). The protein expression of liver SCP2 was also detected in all the patients by Western blotting. At the same time, the bile was also analyzed with biochemical techniques and the Cholesterol Saturation Index (CSI) was calculated. RESULTS The mRNA and protein expression of SCP2 was significantly increased in cholesterol gallstone patients compared to those of non-gallstone patients. Moreover, SCP2 was expressed at higher levels in hereditary cholesterol gallstone patients than that of non-hereditary cholesterol gallstone patients. There was significant difference observed in CSI between cholesterol gallstone patients and non-gallstone patients, but not in CSI between hereditary and non-hereditary cholesterol gallstone patients. CONCLUSIONS SCP2 was overexpressed in hereditary cholesterol gallstone patients compared to non-hereditary cholesterol gallstone patients. This finding indicated that SCP2 might be one of the genetic factors contributing to cholesterol gallstone formation, which was always accompanied by the increase of bile lithogenicity.
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Affiliation(s)
- YunFeng Cui
- Department of Surgery, Tianjin Nankai Hospital, Nankai Clinical School of Medicine, Tianjin Medical University, 122 Sanwei Road Nankai District, Tianjin 300100, PR China
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Atshaves B, Martin G, Hostetler H, McIntosh A, Kier A, Schroeder F. Liver fatty acid-binding protein and obesity. J Nutr Biochem 2010; 21:1015-32. [PMID: 20537520 PMCID: PMC2939181 DOI: 10.1016/j.jnutbio.2010.01.005] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 12/17/2022]
Abstract
While low levels of unesterified long chain fatty acids (LCFAs) are normal metabolic intermediates of dietary and endogenous fat, LCFAs are also potent regulators of key receptors/enzymes and at high levels become toxic detergents within the cell. Elevated levels of LCFAs are associated with diabetes, obesity and metabolic syndrome. Consequently, mammals evolved fatty acid-binding proteins (FABPs) that bind/sequester these potentially toxic free fatty acids in the cytosol and present them for rapid removal in oxidative (mitochondria, peroxisomes) or storage (endoplasmic reticulum, lipid droplets) organelles. Mammals have a large (15-member) family of FABPs with multiple members occurring within a single cell type. The first described FABP, liver-FABP (L-FABP or FABP1), is expressed in very high levels (2-5% of cytosolic protein) in liver as well as in intestine and kidney. Since L-FABP facilitates uptake and metabolism of LCFAs in vitro and in cultured cells, it was expected that abnormal function or loss of L-FABP would reduce hepatic LCFA uptake/oxidation and thereby increase LCFAs available for oxidation in muscle and/or storage in adipose. This prediction was confirmed in vitro with isolated liver slices and cultured primary hepatocytes from L-FABP gene-ablated mice. Despite unaltered food consumption when fed a control diet ad libitum, the L-FABP null mice exhibited age- and sex-dependent weight gain and increased fat tissue mass. The obese phenotype was exacerbated in L-FABP null mice pair fed a high-fat diet. Taken together with other findings, these data suggest that L-FABP could have an important role in preventing age- or diet-induced obesity.
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Affiliation(s)
- B.P. Atshaves
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466
| | - G.G. Martin
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466
| | - H.A. Hostetler
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466
| | - A.L. McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466
| | - A.B. Kier
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843-4467
| | - F. Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466
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NMR and X-ray structures of the putative sterol carrier protein 2 from Thermus thermophilus HB8 show conformational changes. ACTA ACUST UNITED AC 2010; 11:247-56. [DOI: 10.1007/s10969-010-9096-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/23/2010] [Indexed: 11/27/2022]
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Radek JT, Dyer DH, Lan Q. Effects of mutations in Aedes aegypti sterol carrier protein-2 on the biological function of the protein. Biochemistry 2010; 49:7532-41. [PMID: 20681612 DOI: 10.1021/bi902026v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Sterol carrier protein-2 (SCP-2) is a nonspecific intracellular lipid carrier protein. However, the molecular mechanism of ligand selectivity and the in vivo function of SCP-2 remain unclear. In this study, we used site-directed mutagenesis to investigate the ligand selectivity and in vivo function of the yellow fever mosquito sterol carrier protein-2 protein (AeSCP-2). Mutations to amino acids in AeSCP-2 known to interact with bound ligand also weakened NBD-cholesterol binding. Substitution of amino acids in the ligand cavity changed the ligand specificity of mutant AeSCP-2. Overexpressing wild-type AeSCP-2 in the Aedes aegypti cultured Aag-2 cells resulted in an increase in the level of incorporation of [(3)H]cholesterol. However, overexpressing mutants that were deleterious to the binding of NBD-cholesterol in AeSCP-2 showed a loss of ability to enhance uptake of [(3)H]cholesterol in cultured cells. Interestingly, when [(3)H]palmitic acid was used as the substrate for incorporation in vivo, there was no change in the levels of incorporation with overexpression of wild-type protein or mutated AeSCP-2s. The in vivo data suggest that AeSCP-2 is involved in sterol uptake, but not fatty acid uptake. This is the first report that the cholesterol binding ability may directly correlate with AeSCP-2's in vivo function in aiding the uptake of cholesterol.
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Affiliation(s)
- James T Radek
- Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Storey SM, Atshaves BP, McIntosh AL, Landrock KK, Martin GG, Huang H, Ross Payne H, Johnson JD, Macfarlane RD, Kier AB, Schroeder F. Effect of sterol carrier protein-2 gene ablation on HDL-mediated cholesterol efflux from cultured primary mouse hepatocytes. Am J Physiol Gastrointest Liver Physiol 2010; 299:G244-54. [PMID: 20395534 PMCID: PMC2904118 DOI: 10.1152/ajpgi.00446.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 04/13/2010] [Indexed: 01/31/2023]
Abstract
Although HDL-mediated cholesterol transport to the liver is well studied, cholesterol efflux from hepatocytes back to HDL is less well understood. Real-time imaging of efflux of 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino)-23,24-bisnor-5-cholen-3beta-ol (NBD-cholesterol), which is poorly esterified, and [(3)H]cholesterol, which is extensively esterified, from cultured primary hepatocytes of wild-type and sterol carrier protein-2 (SCP-2) gene-ablated mice showed that 1) NBD-cholesterol efflux was affected by the type of lipoprotein acceptor, i.e., HDL3 over HDL2; 2) NBD-cholesterol efflux was rapid (detected in 1-2 min) and resolved into fast [half time (t((1/2))) = 2.4 min, 6% of total] and slow (t((1/2)) = 26.5 min, 94% of total) pools, consistent with protein- and vesicle-mediated cholesterol transfer, respectively; 3) SCP-2 gene ablation increased efflux of NBD-cholesterol, as well as [(3)H]cholesterol, albeit less so due to competition by esterification of [(3)H]cholesterol, but not NBD-cholesterol; and 4) SCP-2 gene ablation increased initial rate (2.3-fold) and size (9.7-fold) of rapid effluxing sterol, suggesting an increased contribution of molecular cholesterol transfer. In addition, colocalization, double-immunolabeling fluorescence resonance energy transfer, and electron microscopy, as well as cross-linking coimmunoprecipitation, indicated that SCP-2 directly interacted with the HDL receptor, scavenger receptor class B type 1 (SRB1), in hepatocytes. Other membrane proteins in cholesterol efflux [SRB1 and ATP-binding cassettes (ABC) A-1, ABCG-1, ABCG-5, and ABCG-8] and several soluble/vesicle-associated proteins facilitating intracellular cholesterol trafficking (StARDs, NPCs, ORPs) were not upregulated. However, loss of SCP-2 elicited twofold upregulation of liver fatty acid-binding protein (L-FABP), a protein with lower affinity for cholesterol but higher cytosolic concentration than SCP-2. Ablation of SCP-2 and L-FABP decreased HDL-mediated NBD-cholesterol efflux. These results indicate that SCP-2 expression plays a significant role in HDL-mediated cholesterol efflux by regulating the size of rapid vs. slow cholesterol efflux pools and/or eliciting concomitant upregulation of L-FABP in cultured primary hepatocytes.
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Affiliation(s)
- Stephen M Storey
- Departmens of Physiology and Pharmacology, Texas Veterinary Medical Center, Texas A & M University, College Station, TX 77843-4466, USA
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Kumar RB, Shanmugapriya B, Thiyagesan K, Kumar SR, Xavier SM. A search for mosquito larvicidal compounds by blocking the sterol carrying protein, AeSCP-2, through computational screening and docking strategies. Pharmacognosy Res 2010; 2:247-53. [PMID: 21808576 PMCID: PMC3141136 DOI: 10.4103/0974-8490.69126] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 05/22/2010] [Accepted: 09/07/2010] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Sterol is a very vital compound for most of the insects and mosquitoes to complete their life cycle. Unfortunately mosquitoes cannot synthesize the sterol, it depends on mammals for the same. Mosquitoes take the sterol from the plant decays during their larval stage in the form of phytosterol, which is then converted to cholesterol for further growth and reproduction. This conversion occurs with the help of the sterol carrier protein 2(SCP2). METHODS Mosquito populations are controlled by plant-based inhibitors, which inhibit sterol carrier protein (SCPI-Sterol carrier protein inhibitor) activity. In this article, we explain the methods of inhibiting Aedes aegypti SCP2 by insilico methods including natural inhibitor selection and filtrations by virtual screening and interaction studies. RESULTS In this study protein-ligand interactions were carried out with various phytochemicals, as a result of virtual screening Alpha-mangostin and Panthenol were found to be good analogs, and were allowed to dock with the mosquito cholesterol carrier protein AeSCP-2. CONCLUSION Computational selections of SCPIs are highly reliable and novel methods for discovering new and more effective compounds to control mosquitoes.
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Affiliation(s)
- R. Barani Kumar
- Department of Bioinformatics, Sathyabama University, Chennai-600 119, India.
| | | | - K. Thiyagesan
- Department of Zoology and Division of Wildlife Biology, A.V.C. College, Mayiladuthurai -609305, India.
| | - S. Raj Kumar
- Department of Zoology and Division of Wildlife Biology, A.V.C. College, Mayiladuthurai -609305, India.
| | - Suresh M. Xavier
- Department of Bioinformatics, Sathyabama University, Chennai-600 119, India.
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Cockrum RR, Austin KJ, Kim JW, Garbe JR, Fahrenkrug SC, Taylor JF, Cammack KM. Differential gene expression of ewes varying in tolerance to dietary nitrate. J Anim Sci 2010; 88:3187-97. [PMID: 20562356 DOI: 10.2527/jas.2009-2709] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ruminants consuming diets with increased concentrations of nitrate (NO(3)(-)) can accumulate nitrite (NO(2)(-)) in the blood, resulting in toxicity. In a previous experiment, ewes identified as highly tolerant to subacute dietary NO(3)(-) were able to consume greater amounts of NO(3)(-) than lowly tolerant ewes without exhibiting signs of toxicity. We hypothesized that highly tolerant and lowly tolerant ewes differ in their ability to metabolize NO(3)(-) and thereby differ in the expression of hepatic genes involved in NO(3)(-) metabolism. Therefore, our objective was to identify hepatic genes differentially expressed between ewes classified as lowly tolerant and highly tolerant after administration of a subacute quantity of dietary NO(3)(-). Analysis of the Bovine Oligonucleotide Microarray data identified 100 oligonucleotides as differentially expressed (P < 0.05) between lowly tolerant and highly tolerant ewes. Functional analysis of the genes associated with these oligonucleotides revealed 2 response clusters of interest: metabolic and stress. Genes of interest within these 2 clusters (n = 17) and nonclustered genes with the greatest fold changes (FC; n = 5) were selected for validation by real-time reverse-transcription PCR. Relative expression, genomic regulation, and FC agreed between microarray and real-time reverse-transcription-PCR analyses, and FC differences (P < 0.05) between lowly tolerant and highly tolerant ewes were confirmed for 12 genes. Metabolic genes that were downregulated (P ≤ 0.032) in lowly tolerant ewes vs. highly tolerant ewes included aldehyde oxidase 1, argininosuccinate lyase, putative steroid dehydrogenase, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase1, and sterol carrier protein 2. In contrast, the metabolic gene homeobox was upregulated (P = 0.037) in lowly tolerant ewes. The glutathione peroxidase 3 and inter-α (globulin) inhibitor H4 genes in the stress response cluster were upregulated (P ≤ 0.045) in lowly tolerant ewes. Genes with the greatest FC, but did not cluster within the functional analysis included haptoglobin, which was upregulated (P = 0.024) in lowly tolerant ewes, and fatty acid desaturase 2 and thyroid hormone responsive, both of which were downregulated (P ≤ 0.019) in lowly tolerant ewes. Results from this study indicate that hepatic gene expression differs in ewes identified as lowly tolerant and highly tolerant to increased dietary NO(3)(-).
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Affiliation(s)
- R R Cockrum
- Department of Animal Science, University of Wyoming, Laramie, WY 82071, USA
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Gulati S, Liu Y, Munkacsi AB, Wilcox L, Sturley SL. Sterols and sphingolipids: dynamic duo or partners in crime? Prog Lipid Res 2010; 49:353-65. [PMID: 20362613 DOI: 10.1016/j.plipres.2010.03.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
One manner in which eukaryotic cells respond to their environments is by optimizing the composition and proportions of sterols and sphingolipids in membranes. The physical association of the planar ring of sterols with the acyl chains of phospholipids, particularly sphingolipids, produces membrane micro-heterogeneity that is exploited to coordinate several crucial pathways. We hypothesize that these lipid molecules play an integrated role in human disease; when one of the partners is mis-regulated, pathology frequently ensues. Sterols and sphingolipid levels are not coordinated by the action of a single master regulator, however the cross-talk between their metabolic pathways is considerable. We describe our perspectives on the key components of synthesis, catabolism and transport of these lipid partners with an emphasis on evolutionarily conserved reactions that produce disease states when defective.
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Affiliation(s)
- Sonia Gulati
- Institute of Human Nutrition, Columbia University Medical Center, 630 W. 168th St., New York, NY 10032, USA
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46
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Singarapu KK, Radek JT, Tonelli M, Markley JL, Lan Q. Differences in the structure and dynamics of the apo- and palmitate-ligated forms of Aedes aegypti sterol carrier protein 2 (AeSCP-2). J Biol Chem 2010; 285:17046-53. [PMID: 20356842 DOI: 10.1074/jbc.m110.101154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sterol carrier protein-2 (SCP-2) is a nonspecific lipid-binding protein expressed ubiquitously in most organisms. Knockdown of SCP-2 expression in mosquitoes has been shown to result in high mortality in developing adults and significantly lowered fertility. Thus, it is of interest to determine the structure of mosquito SCP-2 and to identify its mechanism of lipid binding. We report here high quality three-dimensional solution structures of SCP-2 from Aedes aegypti determined by NMR spectroscopy in its ligand-free state (AeSCP-2) and in complex with palmitate. Both structures have a similar mixed alpha/beta fold consisting of a five-stranded beta-sheet and four alpha-helices arranged on one side of the beta-sheet. Ligand-free AeSCP-2 exhibited regions of structural heterogeneity, as evidenced by multiple two-dimensional (15)N heteronuclear single-quantum coherence peaks for certain amino acids; this heterogeneity disappeared upon complex formation with palmitate. The binding of palmitate to AeSCP-2 was found to decrease the backbone mobility of the protein but not to alter its secondary structure. Complex formation is accompanied by chemical shift differences and a loss of mobility for residues in the loop between helix alphaI and strand betaA. The structural differences between the alphaI and betaA of the mosquito and the vertebrate SCP-2s may explain the differential specificity (insect versus vertebrate) of chemical inhibitors of the mosquito SCP-2.
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Affiliation(s)
- Kiran K Singarapu
- Department of Biochemistry, National Magnetic Resonance Facility at Madison, Wisconsin 53706, USA
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47
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LARSON RYANT, LORCH JEFFREYM, PRIDGEON JULIAW, BECNEL JAMESJ, CLARK GARYG, LAN QUE. The biological activity of alpha-mangostin, a larvicidal botanic mosquito sterol carrier protein-2 inhibitor. JOURNAL OF MEDICAL ENTOMOLOGY 2010; 47:249-57. [PMID: 20380307 PMCID: PMC2855149 DOI: 10.1603/me09160] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
alpha-Mangostin derived from mangosteen was identified as a mosquito sterol carrier protein-2 inhibitor via high throughput insecticide screening, alpha-Mangostin was tested for its larvicidal activity against third instar larvae of six mosquito species, and the median lethal concentration values range from 0.84 to 2.90 ppm. The residual larvicidal activity of alpha-mangostin was examined under semifield conditions. The results indicated that alpha-mangostin was photolytic with a half-life of 53 min in water under full sunlight exposure. The effect of alpha-mangostin on activities of major detoxification enzymes such as P450, glutathione S-transferase, and esterase was investigated. The results showed that alpha-mangostin significantly elevated activities of P450 and glutathione S-transferase in larvae, whereas it suppressed esterase activity. Toxicity of alpha-mangostin against young rats was studied, and there was no detectable adverse effect at dosages as high as 80 mg/kg. This is the first multifaceted study of the biological activity of alpha-mangostin in mosquitoes. The results suggest that alpha-mangostin may be a lead compound for the development of a new organically based mosquito larvicide.
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Affiliation(s)
- RYAN T. LARSON
- Department of Entomology, University of Wisconsin, Madison, WI 53706
| | - JEFFREY M. LORCH
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706
| | - JULIA W. PRIDGEON
- U.S. Department of Agriculture-Agricultural Research Service, Center for Medical and Veterinary Entomology, 1600 S.W. 23rd Drive, Gainesville, FL 32608
| | - JAMES J. BECNEL
- U.S. Department of Agriculture-Agricultural Research Service, Center for Medical and Veterinary Entomology, 1600 S.W. 23rd Drive, Gainesville, FL 32608
| | - GARY G. CLARK
- U.S. Department of Agriculture-Agricultural Research Service, Center for Medical and Veterinary Entomology, 1600 S.W. 23rd Drive, Gainesville, FL 32608
| | - QUE LAN
- Department of Entomology, University of Wisconsin, Madison, WI 53706
- Corresponding author: Department of Entomology, University of Wisconsin, 1630 Linden Drive, Madison, WI 53706 ()
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Schroeder F, Huang H, McIntosh AL, Atshaves BP, Martin GG, Kier AB. Caveolin, sterol carrier protein-2, membrane cholesterol-rich microdomains and intracellular cholesterol trafficking. Subcell Biochem 2010; 51:279-318. [PMID: 20213548 DOI: 10.1007/978-90-481-8622-8_10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
While the existence of membrane lateral microdomains has been known for over 30 years, interest in these structures accelerated in the past decade due to the discovery that cholesterol-rich microdomains serve important biological functions. It is increasingly appreciated that cholesterol-rich microdomains in the plasma membranes of eukaryotic cells represent an organizing nexus for multiple cellular proteins involved in transmembrane nutrient uptake (cholesterol, fatty acid, glucose, etc.), cell-signaling, immune recognition, pathogen entry, and many other roles. Despite these advances, however, relatively little is known regarding the organization of cholesterol itself in these plasma membrane microdomains. Although a variety of non-sterol markers indicate the presence of microdomains in the plasma membranes of living cells, none of these studies have demonstrated that cholesterol is enriched in these microdomains in living cells. Further, the role of cholesterol-rich membrane microdomains as targets for intracellular cholesterol trafficking proteins such as sterol carrier protein-2 (SCP-2) that facilitate cholesterol uptake and transcellular transport for targeting storage (cholesterol esters) or efflux is only beginning to be understood. Herein, we summarize the background as well as recent progress in this field that has advanced our understanding of these issues.
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Affiliation(s)
- Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC College Station, TX, 77843-4466, USA.
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49
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Martin GG, Atshaves BP, Huang H, McIntosh AL, Williams BJ, Pai PJ, Russell DH, Kier AB, Schroeder F. Hepatic phenotype of liver fatty acid binding protein gene-ablated mice. Am J Physiol Gastrointest Liver Physiol 2009; 297:G1053-65. [PMID: 19815623 PMCID: PMC2850096 DOI: 10.1152/ajpgi.00116.2009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 10/06/2009] [Indexed: 01/31/2023]
Abstract
Although the function of liver fatty acid binding protein in hepatic fatty acid metabolism has been extensively studied, its potential role in hepatic cholesterol homeostasis is less clear. Although hepatic cholesterol accumulation was initially reported in L-FABP-null female mice, that study was performed with early N2 backcross generation mice. To resolve whether the hepatic cholesterol phenotype in these L-FABP(-/-) mice was attributable to genetic inhomogeneity, these L-FABP(-/-) mice were further backcrossed to C57Bl/6 mice up to the N10 (99.9% homogeneity) generation. Hepatic total cholesterol accumulation was observed in female, but not male, L-FABP(-/-) mice at all (N2, N4, N6, N10) backcross generations examined. The greater total cholesterol was due to increased hepatic levels of both unesterified (free) cholesterol and esterified cholesterol. Altered hepatic cholesterol accumulation correlated directly with L-FABP's ability to bind cholesterol with high affinity as shown by direct L-FABP binding of fluorescent cholesterol analogs (NBD-cholesterol, dansyl-cholesterol), a photoactivatable cholesterol analog [free cholesterol benzophenone (FCBP)], and free cholesterol (circular dichroism, isothermal titration microcalorimetry). One mole of fluorescent sterol was bound per mole of L-FABP. This was confirmed by photo-cross-linking studies with the photoactivatable cholesterol analog FCBP and by isothermal titration calorimetry with free cholesterol, which showed that L-FABP bound only one sterol molecule per L-FABP molecule. In contrast, the hepatic phenotype of male, but not female, L-FABP(-/-) mice was characterized by decreased hepatic triacylglycerol levels at all backcross generations examined. Taken together, these data support the hypothesis that L-FABP plays a role in physiological regulation of not only hepatic fatty acid metabolism, but also that of hepatic cholesterol.
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Affiliation(s)
- Gregory G Martin
- Dept. of Physiology & Pharmacology, Texas A&M Univ., College Station, 77843-4466, USA
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50
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Atshaves BP, McIntosh AL, Martin GG, Landrock D, Payne HR, Bhuvanendran S, Landrock KK, Lyuksyutova OI, Johnson JD, Macfarlane RD, Kier AB, Schroeder F. Overexpression of sterol carrier protein-2 differentially alters hepatic cholesterol accumulation in cholesterol-fed mice. J Lipid Res 2009; 50:1429-47. [PMID: 19289417 DOI: 10.1194/jlr.m900020-jlr200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although in vitro studies suggest a role for sterol carrier protein-2 (SCP-2) in cholesterol trafficking and metabolism, the physiological significance of these observations remains unclear. This issue was addressed by examining the response of mice overexpressing physiologically relevant levels of SCP-2 to a cholesterol-rich diet. While neither SCP-2 overexpression nor cholesterol-rich diet altered food consumption, increased weight gain, hepatic lipid, and bile acid accumulation were observed in wild-type mice fed the cholesterol-rich diet. SCP-2 overexpression further exacerbated hepatic lipid accumulation in cholesterol-fed females (cholesterol/cholesteryl esters) and males (cholesterol/cholesteryl esters and triacyglycerol). Primarily in female mice, hepatic cholesterol accumulation induced by SCP-2 overexpression was associated with increased levels of LDL-receptor, HDL-receptor scavenger receptor-B1 (SR-B1) (as well as PDZK1 and/or membrane-associated protein 17 kDa), SCP-2, liver fatty acid binding protein (L-FABP), and 3alpha-hydroxysteroid dehydrogenase, without alteration of other proteins involved in cholesterol uptake (caveolin), esterification (ACAT2), efflux (ATP binding cassette A-1 receptor, ABCG5/8, and apolipoprotein A1), or oxidation/transport of bile salts (cholesterol 7alpha-hydroxylase, sterol 27alpha-hydroxylase, Na(+)/taurocholate cotransporter, Oatp1a1, and Oatp1a4). The effects of SCP-2 overexpression and cholesterol-rich diet was downregulation of proteins involved in cholesterol transport (L-FABP and SR-B1), cholesterol synthesis (related to sterol regulatory element binding protein 2 and HMG-CoA reductase), and bile acid oxidation/transport (via Oapt1a1, Oatp1a4, and SCP-x). Levels of serum and hepatic bile acids were decreased in cholesterol-fed SCP-2 overexpression mice, especially in females, while the total bile acid pool was minimally affected. Taken together, these findings support an important role for SCP-2 in hepatic cholesterol homeostasis.
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Affiliation(s)
- Barbara P Atshaves
- Department of Physiology and Pharmacology, Texas A&M University, Texas Veterinary Medical Center, College Station, TX 77843-4466, USA
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