1
|
Lee I, Wallace ZS, Wang Y, Park S, Nam H, Majithia AR, Ideker T. A genotype-phenotype transformer to assess and explain polygenic risk. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.10.23.619940. [PMID: 40291728 PMCID: PMC12026415 DOI: 10.1101/2024.10.23.619940] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2025]
Abstract
Genome-wide association studies have linked millions of genetic variants to biomedical phenotypes, but their utility has been limited by lack of mechanistic understanding and widespread epistatic interactions. Recently, Transformer models have emerged as a powerful machine learning architecture with potential to address these and other challenges. Accordingly, here we introduce the Genotype-to-Phenotype Transformer (G2PT), a framework for modeling hierarchical information flow among variants, genes, multigenic systems, and phenotypes. As proof-of-concept, we use G2PT to model the genetics of TG/HDL (triglycerides to high-density lipoprotein cholesterol), an indicator of metabolic health. G2PT predicts this trait via attention to 1,395 variants underlying at least 20 systems, including immune response and cholesterol transport, with accuracy exceeding state-of-the-art. It implicates 40 epistatic interactions, including epistasis between APOA4 and CETP in phospholipid transfer, a target pathway for cholesterol modification. This work positions hierarchical graph transformers as a next-generation approach to polygenic risk.
Collapse
|
2
|
Durairajan SSK, Singh AK, Iyaswamy A. Peroxisome proliferator-activated receptor agonists: A new hope towards the management of alcoholic liver disease. World J Gastroenterol 2024; 30:3965-3971. [PMID: 39351059 PMCID: PMC11438660 DOI: 10.3748/wjg.v30.i35.3965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 08/11/2024] [Accepted: 08/26/2024] [Indexed: 09/13/2024] Open
Abstract
In this editorial, we examine a paper by Koizumi et al, on the role of peroxisome proliferator-activated receptor (PPAR) agonists in alcoholic liver disease (ALD). The study determined whether elafibranor protected the intestinal barrier and reduced liver fibrosis in a mouse model of ALD. The study also underlines the role of PPARs in intestinal barrier function and lipid homeostasis, which are both affected by ALD. Effective therapies are necessary for ALD because it is a critical health issue that affects people worldwide. This editorial analyzes the possibility of PPAR agonists as treatments for ALD. As key factors of inflammation and metabolism, PPARs offer multiple methods for managing the complex etiology of ALD. We assess the abilities of PPARα, PPARγ, and PPARβ/δ agonists to prevent steatosis, inflammation, and fibrosis due to liver diseases. Recent research carried out in preclinical and clinical settings has shown that PPAR agonists can reduce the severity of liver disease. This editorial discusses the data analyzed and the obstacles, advantages, and mechanisms of action of PPAR agonists for ALD. Further research is needed to understand the efficacy, safety, and mechanisms of PPAR agonists for treating ALD.
Collapse
Affiliation(s)
- Siva Sundara Kumar Durairajan
- Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Tiruvarur 610005, India
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong 999077, China
| | - Abhay Kumar Singh
- Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Tiruvarur 610005, India
| | - Ashok Iyaswamy
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China
- Department of Biochemistry, Karpagam Academy of Higher Education, Coimbatore 641021, India
| |
Collapse
|
3
|
Chen G, Xiong S, Jing Q, van Gestel CAM, van Straalen NM, Roelofs D, Sun L, Qiu H. Maternal exposure to polystyrene nanoparticles retarded fetal growth and triggered metabolic disorders of placenta and fetus in mice. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158666. [PMID: 36108837 DOI: 10.1016/j.scitotenv.2022.158666] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 06/15/2023]
Abstract
Microplastics can enter the human body via direct body contact or the food chain, increasing the likelihood of adverse impacts on pregnancy and fetal development. We investigated the potential effects and modes of action of polystyrene nanoplastics (PS-NPs) in placenta and fetus using mice as a model species. Maternal PS-NP exposure (100 nm; 1 and 10 mg/L) via drinking water induced a significant decline in fetal weights at the higher exposure concentration. Abnormal morphologies of cells in the placenta and fetus were observed after exposure. For the placenta, transcriptomic analyses indicated that PS-NPs significantly disturbed cholesterol metabolism and complement and coagulation cascades pathways. Metabolomics showed appreciable metabolic disorders, particularly affecting sucrose and daidzein concentrations. For the fetal skeletal muscle, transcriptomics identified many significantly regulated genes, involving muscle tissue development, lipid metabolism, and skin formation. Transcriptomic analysis of the placenta and fetal skeletal muscle at the high PS-NP concentration showed that APOA4 and its transcriptional factors, facilitating cholesterol transportation, were significantly regulated in both tissues. Our study revealed that PS-NPs caused fetal growth restriction and significantly disturbed cholesterol metabolism in both placenta and fetus, offering new insights into the mechanisms underlying the placental and fetal effects in mice exposed to PS-NPs.
Collapse
Affiliation(s)
- Guangquan Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Department of Fetal Medicine and Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 201204, China
| | - Shiyi Xiong
- Shanghai Key Laboratory of Maternal Fetal Medicine, Department of Fetal Medicine and Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 201204, China
| | - Qiao Jing
- Department of Pediatrics, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai 200120, China
| | - Cornelis A M van Gestel
- Amsterdam Institute for Life and Environment (A-LIFE), Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Nico M van Straalen
- Amsterdam Institute for Life and Environment (A-LIFE), Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Dick Roelofs
- KeyGene, Agro Business Park 90, 6708 PW Wageningen, the Netherlands
| | - Luming Sun
- Shanghai Key Laboratory of Maternal Fetal Medicine, Department of Fetal Medicine and Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 201204, China.
| | - Hao Qiu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
| |
Collapse
|
4
|
Mizukawa Y, Amagase Y, Urushidani T. Extraction of peroxisome proliferator-activated receptor α agonist-induced lipid metabolism-related and unrelated genes in rat liver and analysis of their genomic location. J Toxicol Sci 2020; 45:449-473. [PMID: 32741897 DOI: 10.2131/jts.45.449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Although peroxisome proliferator-activated receptor α (PPARα) agonists are obviously hepatocarcinogenic in rodents, they have been widely used for dyslipidemia and proven to be safe for clinical use without respect to the species difference. It is established that PPARα acts as a part of the transcription factor complex, but its precise mechanism is still unknown. Using the data of Toxicogenomics Database, reliable genes responsive to PPARα agonists, clofibrate, fenofibrate and WY-14,643, in rat liver, were extracted from both in vivo and in vitro data, and sorted by their fold increase. It was found that there were many genes responding to fibrates exclusively in vivo. Most of the in vivo specific genes appear to be unrelated to lipid metabolism and are not upregulated in the kidney. Fifty-seven genes directly related to cell proliferation were extracted from in vivo data, but they were not induced in vitro at all. Analysis of PPAR-responsive elements could not explain the observed difference in induction. To evaluate possible interaction between neighboring genes in gene expression, the correlation of the fold changes of neighboring genes for 22 drugs with various PPARα agonistic potencies were calculated for the genes showing more than 2.5 fold induction by 3 fibrates in vivo, and their genomic location was compared with that of the human orthologue. In the present study, many candidates of genes other than lipid metabolism were selected, and these could be good starting points to elucidate the mechanism of PPARα agonist-induced rodent-specific toxicity.
Collapse
Affiliation(s)
- Yumiko Mizukawa
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
| | - Yoko Amagase
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
| | - Tetsuro Urushidani
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
| |
Collapse
|
5
|
Low-arginine and low-protein diets induce hepatic lipid accumulation through different mechanisms in growing rats. Nutr Metab (Lond) 2020; 17:60. [PMID: 32774438 PMCID: PMC7398226 DOI: 10.1186/s12986-020-00477-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 07/22/2020] [Indexed: 01/16/2023] Open
Abstract
Background Dietary protein deficiency and amino acid imbalance cause hepatic fat accumulation. We previously demonstrated that only arginine deficiency or total amino acid deficiency in a diet caused significant hepatic triglyceride (TG) accumulation in young Wistar rats. In this study, we explored the mechanisms of fatty liver formation in these models. Methods We fed 6-week-old male Wistar rats a control diet (containing an amino acid mixture equivalent to 15% protein), a low-total-amino acid diet (equivalent to 5% protein; 5PAA), and a low-arginine diet (only the arginine content is as low as that of the 5PAA diet) for 2 weeks. Results Much greater hepatic TG accumulation was observed in the low-arginine group than in the low-total-amino acid group. The lipid consumption rate and fatty acid uptake in the liver did not significantly differ between the groups. In contrast, the low-total-amino acid diet potentiated insulin sensitivity and related signaling in the liver and enhanced de novo lipogenesis. The low-arginine diet also inhibited hepatic very-low-density lipoprotein secretion without affecting hepatic insulin signaling and lipogenesis. Conclusions Although the arginine content of the low-arginine diet was as low as that of the low-total-amino acid diet, the two diets caused fatty liver via completely different mechanisms. Enhanced lipogenesis was the primary cause of a low-protein diet-induced fatty liver, whereas lower very-low-density lipoprotein secretion caused low-arginine diet-induced fatty liver.
Collapse
|
6
|
Freitas HR, Ferreira GDC, Trevenzoli IH, Oliveira KDJ, de Melo Reis RA. Fatty Acids, Antioxidants and Physical Activity in Brain Aging. Nutrients 2017; 9:nu9111263. [PMID: 29156608 PMCID: PMC5707735 DOI: 10.3390/nu9111263] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/11/2017] [Accepted: 11/14/2017] [Indexed: 12/25/2022] Open
Abstract
Polyunsaturated fatty acids and antioxidants are important mediators in the central nervous system. Lipid derivatives may control the production of proinflammatory agents and regulate NF-κB activity, microglial activation, and fatty acid oxidation; on the other hand, antioxidants, such as glutathione and ascorbate, have been shown to signal through transmitter receptors and protect against acute and chronic oxidative stress, modulating the activity of different signaling pathways. Several authors have investigated the role of these nutrients in the brains of the young and the aged in degenerative diseases such as Alzheimer’s and Parkinson’s, and during brain aging due to adiposity- and physical inactivity-mediated metabolic disturbances, chronic inflammation, and oxidative stress. Through a literature review, we aimed to highlight recent data on the role of adiposity, fatty acids, antioxidants, and physical inactivity in the pathophysiology of the brain and in the molecular mechanisms of senescence. Data indicate the complexity and necessity of endogenous/dietary antioxidants for the maintenance of redox status and the control of neuroglial signaling under stress. Recent studies also indicate that omega-3 and -6 fatty acids act in a competitive manner to generate mediators for energy metabolism, influencing feeding behavior, neural plasticity, and memory during aging. Finding pharmacological or dietary resources that mitigate or prevent neurodegenerative affections continues to be a great challenge and requires additional effort from researchers, clinicians, and nutritionists in the field.
Collapse
Affiliation(s)
- Hércules Rezende Freitas
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Gustavo da Costa Ferreira
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
- Laboratory of Neuroenergetics and Inborn Errors of Metabolism, Institute of Medical Biochemistry Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Isis Hara Trevenzoli
- Laboratory of Molecular Endocrinology, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Karen de Jesus Oliveira
- Laboratory of Endocrine Physiology and Metabology, Biomedical Institute, Universidade Federal Fluminense, Niterói 24210-130, Brazil.
| | - Ricardo Augusto de Melo Reis
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| |
Collapse
|
7
|
Freitas HR, Isaac AR, Malcher-Lopes R, Diaz BL, Trevenzoli IH, De Melo Reis RA. Polyunsaturated fatty acids and endocannabinoids in health and disease. Nutr Neurosci 2017; 21:695-714. [PMID: 28686542 DOI: 10.1080/1028415x.2017.1347373] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) are lipid derivatives of omega-3 (docosahexaenoic acid, DHA, and eicosapentaenoic acid, EPA) or of omega-6 (arachidonic acid, ARA) synthesized from membrane phospholipids and used as a precursor for endocannabinoids (ECs). They mediate significant effects in the fine-tune adjustment of body homeostasis. Phyto- and synthetic cannabinoids also rule the daily life of billions worldwide, as they are involved in obesity, depression and drug addiction. Consequently, there is growing interest to reveal novel active compounds in this field. Cloning of cannabinoid receptors in the 90s and the identification of the endogenous mediators arachidonylethanolamide (anandamide, AEA) and 2-arachidonyglycerol (2-AG), led to the characterization of the endocannabinoid system (ECS), together with their metabolizing enzymes and membrane transporters. Today, the ECS is known to be involved in diverse functions such as appetite control, food intake, energy balance, neuroprotection, neurodegenerative diseases, stroke, mood disorders, emesis, modulation of pain, inflammatory responses, as well as in cancer therapy. Western diet as well as restriction of micronutrients and fatty acids, such as DHA, could be related to altered production of pro-inflammatory mediators (e.g. eicosanoids) and ECs, contributing to the progression of cardiovascular diseases, diabetes, obesity, depression or impairing conditions, such as Alzheimer' s disease. Here we review how diets based in PUFAs might be linked to ECS and to the maintenance of central and peripheral metabolism, brain plasticity, memory and learning, blood flow, and genesis of neural cells.
Collapse
Affiliation(s)
- Hércules Rezende Freitas
- a Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho , Universidade Federal do Rio de Janeiro, Cidade Universitária , Ilha do Fundão, Rio de Janeiro , RJ 21941-902 , Brazil
| | - Alinny Rosendo Isaac
- a Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho , Universidade Federal do Rio de Janeiro, Cidade Universitária , Ilha do Fundão, Rio de Janeiro , RJ 21941-902 , Brazil
| | | | - Bruno Lourenço Diaz
- c Laboratory of Inflammation, Institute of Biophysics Carlos Chagas Filho , Universidade Federal do Rio de Janeiro, Cidade Universitária , Ilha do Fundão, Rio de Janeiro , RJ 21941-902 , Brazil
| | - Isis Hara Trevenzoli
- d Laboratory of Molecular Endocrinology, Institute of Biophysics Carlos Chagas Filho , Universidade Federal do Rio de Janeiro, Cidade Universitária , Ilha do Fundão, Rio de Janeiro , RJ 21941-902 , Brazil
| | - Ricardo Augusto De Melo Reis
- a Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho , Universidade Federal do Rio de Janeiro, Cidade Universitária , Ilha do Fundão, Rio de Janeiro , RJ 21941-902 , Brazil
| |
Collapse
|
8
|
The role and regulation of the peroxisome proliferator activated receptor alpha in human liver. Biochimie 2017; 136:75-84. [DOI: 10.1016/j.biochi.2016.12.019] [Citation(s) in RCA: 273] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/24/2016] [Accepted: 12/31/2016] [Indexed: 12/16/2022]
|
9
|
Qin W, Li X, Xie L, Li S, Liu J, Jia L, Dong X, Ren X, Xiao J, Yang C, Zhou Y, Chen Z. A long non-coding RNA, APOA4-AS, regulates APOA4 expression depending on HuR in mice. Nucleic Acids Res 2016; 44:6423-33. [PMID: 27131369 PMCID: PMC5291254 DOI: 10.1093/nar/gkw341] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/18/2016] [Indexed: 11/13/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) have been shown to be critical biomarkers or therapeutic targets for human diseases. However, only a small number of lncRNAs were screened and characterized. Here, we identified 15 lncRNAs, which are associated with fatty liver disease. Among them, APOA4-AS is shown to be a concordant regulator of Apolipoprotein A-IV (APOA4) expression. APOA4-AS has a similar expression pattern with APOA4 gene. The expressions of APOA4-AS and APOA4 are both abnormally elevated in the liver of ob/ob mice and patients with fatty liver disease. Knockdown of APOA4-AS reduces APOA4 expression both in vitro and in vivo and leads to decreased levels of plasma triglyceride and total cholesterol in ob/ob mice. Mechanistically, APOA4-AS directly interacts with mRNA stabilizing protein HuR and stabilizes APOA4 mRNA. Deletion of HuR dramatically reduces both APOA4-AS and APOA4 transcripts. This study uncovers an anti-sense lncRNA (APOA4-AS), which is co-expressed with APOA4, and concordantly and specifically regulates APOA4 expression both in vitro and in vivo with the involvement of HuR.
Collapse
Affiliation(s)
- Wangshu Qin
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xinzhi Li
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Liwei Xie
- Division of Gastroenterology and Hepatology, Digestive Disease Institute, Shanghai Tongji Hospital, Tongji University School of Medicine, 389 Xin Cun Road, Shanghai 200065, China
| | - Sha Li
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Jianan Liu
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Linna Jia
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xue Dong
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xiaomeng Ren
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Junjie Xiao
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Changqing Yang
- China and Regeneration and Ageing Lab, Experimental Center of Life Sciences, School of Life Science, Shanghai University, 333 Nan Chen Road, Shanghai 200444, China
| | - Yifa Zhou
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Zheng Chen
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| |
Collapse
|
10
|
Implications of the endogenous PPAR-gamma ligand, 15-deoxy-delta-12, 14-prostaglandin J2, in diabetic retinopathy. Life Sci 2016; 153:93-9. [PMID: 27060220 DOI: 10.1016/j.lfs.2016.03.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/24/2016] [Accepted: 03/29/2016] [Indexed: 01/09/2023]
Abstract
Diabetic retinopathy, a common secondary complication of diabetes mellitus, involves extensive damage to the retinal microvasculature. Retina, being a susceptible target, is highly prone to hyperglycemia-induced molecular damages. PPAR receptor, chiefly gamma subtype, mediates numerous responses related to glucose metabolism and hence is utilized, through its agonism, for the restoration of normal insulin sensitivity and glucose homeostasis in the body. Although a number of synthetic PPAR-gamma receptor agonists have been developed and are being employed for treatment purposes, the role of its endogenous ligand in the prevention of diabetic retinopathy is poorly acknowledged. Activation of PPAR-gamma receptor, via endogenous agents, provides a natural defensive shield against various hyperglycemia-induced pathological conditions. Although the biological levels of 15d-PGJ2 (an endogenous agonist of PPAR-gamma receptor) are found to be below the concentration required to trigger PPAR-gamma-mediated actions, employment of several advanced methods for the exogenous administration of this ligand might provide a beneficial option. Besides, 15d-PGJ2-induced defense is better than any of the newly developed alternative therapies, such as anti-inflammatory, anti-angiogenic or anti-apoptotic agents, of diabetic retinopathy, since it singularly provides, virtually, a complete protection package against all these pathological eventualities. Therefore, the physiology of this endogenous PPAR-gamma ligand might, possibly, be exploited to a great extent for the development of prophylactic agents, in order to restrict the progression of diabetic retinopathy.
Collapse
|
11
|
Chen CH, Chen TH, Wu MY, Chen JR, Hong LY, Zheng CM, Chiu IJ, Lin YF, Hsu YH. Peroxisome Proliferator-Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na +/H + Exchanger NHE1. Mol Med 2015; 21:886-889. [PMID: 26623927 DOI: 10.2119/molmed.2015.00196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/23/2015] [Indexed: 12/18/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na+/H+ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na+/H+ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin.
Collapse
Affiliation(s)
- Cheng-Hsien Chen
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Tso-Hsiao Chen
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Mei-Yi Wu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Jia-Rung Chen
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Li-Yu Hong
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Cai-Mei Zheng
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - I-Jen Chiu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yuh-Feng Lin
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yung-Ho Hsu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| |
Collapse
|
12
|
Schrader M, Costello JL, Godinho LF, Azadi AS, Islinger M. Proliferation and fission of peroxisomes - An update. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:971-83. [PMID: 26409486 DOI: 10.1016/j.bbamcr.2015.09.024] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/16/2015] [Accepted: 09/21/2015] [Indexed: 12/23/2022]
Abstract
In mammals, peroxisomes perform crucial functions in cellular metabolism, signalling and viral defense which are essential to the health and viability of the organism. In order to achieve this functional versatility peroxisomes dynamically respond to molecular cues triggered by changes in the cellular environment. Such changes elicit a corresponding response in peroxisomes, which manifests itself as a change in peroxisome number, altered enzyme levels and adaptations to the peroxisomal structure. In mammals the generation of new peroxisomes is a complex process which has clear analogies to mitochondria, with both sharing the same division machinery and undergoing a similar division process. How the regulation of this division process is integrated into the cell's response to different stimuli, the signalling pathways and factors involved, remains somewhat unclear. Here, we discuss the mechanism of peroxisomal fission, the contributions of the various division factors and examine the potential impact of post-translational modifications, such as phosphorylation, on the proliferation process. We also summarize the signalling process and highlight the most recent data linking signalling pathways with peroxisome proliferation.
Collapse
Affiliation(s)
- Michael Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, EX4 4QJ, Exeter Devon, UK; Centre for Cell Biology, Department of Biology, University of Aveiro, 3810-193, Aveiro, Portugal.
| | - Joseph L Costello
- College of Life and Environmental Sciences, Biosciences, University of Exeter, EX4 4QJ, Exeter Devon, UK
| | - Luis F Godinho
- Centre for Cell Biology, Department of Biology, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Afsoon S Azadi
- College of Life and Environmental Sciences, Biosciences, University of Exeter, EX4 4QJ, Exeter Devon, UK
| | - Markus Islinger
- Neuroanatomy, Center for Biomedicine and Medical Technology Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| |
Collapse
|
13
|
An experimental study on amelioration of dyslipidemia-induced atherosclesis by Clematichinenoside through regulating Peroxisome proliferator-activated receptor-α mediated apolipoprotein A-I, A-II and C-III. Eur J Pharmacol 2015; 761:362-74. [PMID: 25979856 DOI: 10.1016/j.ejphar.2015.04.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 04/10/2015] [Accepted: 04/15/2015] [Indexed: 01/09/2023]
Abstract
Prevention or amelioration the prevalence of atherosclerosis has been an effective strategy in the management of cardiovascular diseases. The aim of the study was to scrutinize the effect of Clematichinenoside (AR) on dyslipidemia-induced atherosclerosis and explore its capability on expression of Peroxisome proliferator-activated receptor-α (PPAR-alpha), apolipoprotein A-I (APOA1) and A-II (APOA2), and suppression of apolipoprotein C-III (APOC3) genes and proteins. In the present study, we investigated atherosclerosis effect of AR using a combination of high-fat diet and balloon injury model in rabbits. The levels of biochemical indicators were evaluated in plasma, liver and HepG2 cells using immunoassay technology. In order to expose the underlying mechanism, we evaluated the regulation of PPAR-alpha, APOA1, APOA2 and APOC3 expressions by AR, and we further evaluated the interactions between them after transfection with shRNA (shPPAR-alpha) and, the action of PPAR-alpha in HepG2 cells. We could find that AR markedly promoted the PPAR-alpha transfer from cytoplasm to nucleus which resulted in the alteration of APOA1, APOA2 and APOC3 expressions in HepG2 cells. Moreover, AR significantly reduced total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) levels, and elevated high-density lipoprotein cholesterol (HDL-C) level, which play an important role in dyslipidemia-induced atherosclerosis. In conclusion, AR ameliorated atherosclerosis via the regulation of hepatic lipid metabolism, and AR also contributed to the activation of PPAR-alpha, APOA1, APOA2 and APOC3. Therefore, AR could be a potential therapeutic agent in the treatment of atherosclerosis.
Collapse
|
14
|
Wang F, Kohan AB, Lo CM, Liu M, Howles P, Tso P. Apolipoprotein A-IV: a protein intimately involved in metabolism. J Lipid Res 2015; 56:1403-18. [PMID: 25640749 DOI: 10.1194/jlr.r052753] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Indexed: 01/07/2023] Open
Abstract
The purpose of this review is to summarize our current understanding of the physiological roles of apoA-IV in metabolism, and to underscore the potential for apoA-IV to be a focus for new therapies aimed at the treatment of diabetes and obesity-related disorders. ApoA-IV is primarily synthesized by the small intestine, attached to chylomicrons by enterocytes, and secreted into intestinal lymph during fat absorption. In circulation, apoA-IV is associated with HDL and chylomicron remnants, but a large portion is lipoprotein free. Due to its anti-oxidative and anti-inflammatory properties, and because it can mediate reverse-cholesterol transport, proposed functions of circulating apoA-IV have been related to protection from cardiovascular disease. This review, however, focuses primarily on several properties of apoA-IV that impact other metabolic functions related to food intake, obesity, and diabetes. In addition to participating in triglyceride absorption, apoA-IV can act as an acute satiation factor through both peripheral and central routes of action. It also modulates glucose homeostasis through incretin-like effects on insulin secretion, and by moderating hepatic glucose production. While apoA-IV receptors remain to be conclusively identified, the latter modes of action suggest that this protein holds therapeutic promise for treating metabolic disease.
Collapse
Affiliation(s)
- Fei Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Alison B Kohan
- Department of Nutritional Sciences, University of Connecticut Advanced Technology Laboratory, Storrs, CT 06269
| | - Chun-Min Lo
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Philip Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| |
Collapse
|
15
|
Ghonem NS, Ananthanarayanan M, Soroka CJ, Boyer JL. Peroxisome proliferator-activated receptor α activates human multidrug resistance transporter 3/ATP-binding cassette protein subfamily B4 transcription and increases rat biliary phosphatidylcholine secretion. Hepatology 2014; 59:1030-42. [PMID: 24122873 PMCID: PMC4049334 DOI: 10.1002/hep.26894] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 09/19/2013] [Accepted: 09/20/2013] [Indexed: 12/11/2022]
Abstract
UNLABELLED Multidrug resistance transporter 3/ATP-binding cassette protein subfamily B4 (MDR3/ABCB4) is a critical determinant of biliary phosphatidylcholine (PC) secretion. Clinically, mutations and partial deficiencies in MDR3 result in cholestatic liver injury. Thus, MDR3 is a potential therapeutic target for cholestatic liver disease. Fenofibrate is a peroxisome proliferator-activated receptor (PPAR) α ligand that has antiinflammatory actions and regulates bile acid detoxification. Here we examined the mechanism by which fenofibrate regulates MDR3 gene expression. Fenofibrate significantly up-regulated MDR3 messenger RNA (mRNA) and protein expression in primary cultured human hepatocytes, and stimulated MDR3 promoter activity in HepG2 cells. In silico analysis of 5'-upstream region of human MDR3 gene revealed a number of PPARα response elements (PPRE). Electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays demonstrated specific binding of PPARα to the human MDR3 promoter. Targeted mutagenesis of three novel PPREs reduced inducibility of the MDR3 promoter by fenofibrate. In collagen sandwich cultured rat hepatocytes, treatment with fenofibrate increased secretion of fluorescent PC into bile canaliculi. CONCLUSION Fenofibrate transactivates MDR3 gene transcription by way of the binding of PPARα to three novel and functionally critical PPREs in the MDR3 promoter. Fenofibrate treatment further stimulates biliary phosphatidylcholine secretion in rat hepatocytes, thereby providing a functional correlate. We have established a molecular mechanism that may contribute to the beneficial use of fenofibrate therapy in human cholestatic liver disease.
Collapse
Affiliation(s)
- Nisanne S. Ghonem
- Department of Internal Medicine, Liver Center; Yale University School of Medicine; New Haven CT
| | | | - Carol J. Soroka
- Department of Internal Medicine, Liver Center; Yale University School of Medicine; New Haven CT
| | - James L. Boyer
- Department of Internal Medicine, Liver Center; Yale University School of Medicine; New Haven CT
| |
Collapse
|
16
|
McMullen PD, Bhattacharya S, Woods CG, Sun B, Yarborough K, Ross SM, Miller ME, McBride MT, LeCluyse EL, Clewell RA, Andersen ME. A map of the PPARα transcription regulatory network for primary human hepatocytes. Chem Biol Interact 2014; 209:14-24. [DOI: 10.1016/j.cbi.2013.11.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 10/14/2013] [Accepted: 11/13/2013] [Indexed: 02/07/2023]
|
17
|
Hoque MT, Robillard KR, Bendayan R. Regulation of breast cancer resistant protein by peroxisome proliferator-activated receptor α in human brain microvessel endothelial cells. Mol Pharmacol 2012; 81:598-609. [PMID: 22266374 DOI: 10.1124/mol.111.076745] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Breast cancer resistance protein (BCRP/ABCG2), an ATP-binding cassette (ABC) membrane-associated drug efflux transporter, is known to localize at the blood-brain barrier (BBB) and can significantly restrict xenobiotic permeability in the brain. The objective of this study is to investigate the regulation of BCRP functional expression by peroxisome proliferator-activated receptor alpha (PPARα), a ligand-activated transcription factor primarily involved in lipid metabolism, in a cerebral microvascular endothelial cell culture system (hCMEC/D3), representative of human BBB. We demonstrate that PPARα-selective ligands (i.e., clofibrate, GW7647) significantly induce BCRP mRNA and protein expression in a time- and concentration-dependent manner, whereas pharmacological inhibitors (i.e., MK886, GW6471) prevent this induction. Using [(3)H]mitoxantrone, an established BCRP substrate, we observe a significant reduction in its cellular accumulation by monolayer cells treated with clofibrate, suggesting increased BCRP efflux activity. In addition, we show a significant decrease in BCRP protein expression and function when PPARα is down-regulated by small interfering RNA. Applying chromatin immunoprecipitation and quantitative real-time polymerase chain reaction, we observe that clofibrate treatment increases PPARα binding to the peroxisome proliferator response element within the ABCG2 gene promoter. This study provides the first evidence of direct BCRP regulation by PPARα in a human in vitro BBB model and suggests new targeting strategies for either improving drug brain bioavailability or increasing neuroprotection.
Collapse
Affiliation(s)
- Md Tozammel Hoque
- Graduate Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | | | | |
Collapse
|
18
|
König B, Fischer S, Schlotte S, Wen G, Eder K, Stangl GI. Monocarboxylate transporter 1 and CD147 are up-regulated by natural and synthetic peroxisome proliferator-activated receptor alpha agonists in livers of rodents and pigs. Mol Nutr Food Res 2011; 54:1248-56. [PMID: 20306479 DOI: 10.1002/mnfr.200900432] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Monocarboxylate transporter (MCT)-1 mediates the transport of ketone bodies and other monocarboxylic acids across the plasma membrane. MCT1 is up-regulated by peroxisome proliferator-activated receptor (PPAR)-alpha, a transcription factor that mediates the adaptive response to fasting by up-regulation of genes involved in fatty acid oxidation and ketogenesis. Here, we show for the first time that MCT1 is up-regulated by dietary natural PPAR-alpha agonists. Both, an oxidized fat and conjugated linoleic acids increased MCT1 mRNA concentration in the liver of rats. Also, in the liver of pigs as non-proliferating species MCT1 was up-regulated upon PPAR-alpha activation by clofibrate, oxidized fat and fasting. Concomitant with up-regulation of MCT1, mRNA level of CD147 was increased in livers of rats and pigs. CD147 is a plasma membrane glycoprotein that is required for translocation and transport activity of MCT1. CD147 mRNA increase upon PPAR-alpha activation could not be observed in mice lacking PPAR-alpha, which also fail in up-regulation of MCT1 indicating a co-regulation of MCT1 and CD147. Analysis of the 5'-flanking region of mouse MCT1 gene by reporter gene assay revealed that promoter activity of mouse MCT1 was not induced by PPAR-alpha, indicating that the 5'-flanking region is not involved in MCT1 regulation by PPAR-alpha.
Collapse
Affiliation(s)
- Bettina König
- Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
| | | | | | | | | | | |
Collapse
|
19
|
van der Meer DLM, Degenhardt T, Väisänen S, de Groot PJ, Heinäniemi M, de Vries SC, Müller M, Carlberg C, Kersten S. Profiling of promoter occupancy by PPARalpha in human hepatoma cells via ChIP-chip analysis. Nucleic Acids Res 2010; 38:2839-50. [PMID: 20110263 PMCID: PMC2875002 DOI: 10.1093/nar/gkq012] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The transcription factor peroxisome proliferator-activated receptor alpha (PPARalpha) is an important regulator of hepatic lipid metabolism. While PPARalpha is known to activate transcription of numerous genes, no comprehensive picture of PPARalpha binding to endogenous genes has yet been reported. To fill this gap, we performed Chromatin immunoprecipitation (ChIP)-chip in combination with transcriptional profiling on HepG2 human hepatoma cells treated with the PPARalpha agonist GW7647. We found that GW7647 increased PPARalpha binding to 4220 binding regions. GW7647-induced binding regions showed a bias around the transcription start site and most contained a predicted PPAR binding motif. Several genes known to be regulated by PPARalpha, such as ACOX1, SULT2A1, ACADL, CD36, IGFBP1 and G0S2, showed GW7647-induced PPARalpha binding to their promoter. A GW7647-induced PPARalpha-binding region was also assigned to SREBP-targets HMGCS1, HMGCR, FDFT1, SC4MOL, and LPIN1, expression of which was induced by GW7647, suggesting cross-talk between PPARalpha and SREBP signaling. Our data furthermore demonstrate interaction between PPARalpha and STAT transcription factors in PPARalpha-mediated transcriptional repression, and suggest interaction between PPARalpha and TBP, and PPARalpha and C/EBPalpha in PPARalpha-mediated transcriptional activation. Overall, our analysis leads to important new insights into the mechanisms and impact of transcriptional regulation by PPARalpha in human liver and highlight the importance of cross-talk with other transcription factors.
Collapse
Affiliation(s)
- David L M van der Meer
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition, Wageningen University, Bomenweg 2, NL-6703 HD Wageningen, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Fang X, Wei Y, Liu Y, Wang J, Dai J. The identification of apolipoprotein genes in rare minnow (Gobiocypris rarus) and their expression following perfluorooctanoic acid exposure. Comp Biochem Physiol C Toxicol Pharmacol 2010; 151:152-9. [PMID: 19800026 DOI: 10.1016/j.cbpc.2009.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/23/2009] [Accepted: 09/24/2009] [Indexed: 12/22/2022]
Abstract
Apolipoproteins play important roles in lipid transport and uptake in vertebrates, and they are associated with pathogenesis of many cardiovascular diseases. However, the diverse apolipoproteins in individual fish species have not been extensively characterized. Partial cDNA sequences encoding ApoA-IV, ApoE, ApoM, ApoL, and ApoO, and full-length cDNA sequences encoding ApoA-I were cloned from rare minnow (Gobiocypris rarus). Sequence analysis showed that these genes, as well as fragments of other known apolipoprotein genes (ApoC-I, ApoC-II, ApoB) of rare minnow had a high similarity (91-96%) to their orthologues in the spotted barbel Hemibarbus mylodon (Teleostei:Cypriniformes). The expression of these nine genes and their possible upstream genes, PPARalpha, PPARgamma, and HNF4alpha, were investigated in rare minnow after subacute exposure to perfluorooctanoic acid (PFOA) for 14days. Results showed that the expression of mRNA for ApoA-I, ApoC-II, and ApoM was significantly downregulated in all PFOA-treated animals. Only fish receiving the highest dose of PFOA showed downregulation of the expression of ApoA-IV and ApoC-I, while fish treated with 10mg PFOA/L showed upregulation of expression of ApoE. Expression of ApoB, ApoO, and ApoL was unchanged between control and treated groups. In addition, the expression of PPARalpha was increased in all dosed fish, while the mRNAs for PPARgamma and HNF4alpha were significantly altered with 30 and 3mg PFOA/L doses, respectively. Therefore, subacute exposure to PFOA resulted in alteration of expression of apolipoproteins and related genes. These changes in gene expression may further influence lipid metabolism or other physiological functions in fish.
Collapse
Affiliation(s)
- Xuemei Fang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, PR China
| | | | | | | | | |
Collapse
|