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Gou X, Tian M, Yan L, Xia P, Ji H, Tan H, Shi W, Yu H, Zhang X. A novel molecular pathway of lipid accumulation in human hepatocytes caused by PFOA and PFOS. ENVIRONMENT INTERNATIONAL 2024; 191:108962. [PMID: 39159514 DOI: 10.1016/j.envint.2024.108962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 07/14/2024] [Accepted: 08/15/2024] [Indexed: 08/21/2024]
Abstract
Exposed to ubiquitously perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) has been associated with non-alcoholic fatty liver disease (NAFLD), yet the underlying molecular mechanism remains elusive. The extrapolation of empirical studies correlating per- and polyfluoroalkyl substance (PFAS) exposure with NAFLD occurrence to real-life exposure was hindered by the limited availability of mechanistic data at environmentally relevant concentrations. Herein, a novel pathway mediating hepatocyte lipid accumulation by PFOA and PFOS at human-relevant dose (<10 μM) was identified by integrating CRISPR-Cas9 genome screening, concentration-dependent transcriptional assay in HepG2 cell and epidemiological data mining. 1) At genetic level, nudt7 showed the highest enriched potency among 569 NAFLD-related genes, and the transcription of nudt7 was significantly downregulated by PFOA and PFOS exposure (<7 μM). 2) At molecular pathway, upon exposure to ≤10-4 μM PFOA and PFOS, the downregulation of nudt7 transcriptional expression triggered the reduction of Ace-CoA hydrolase activity. 3) At cellular level, increased lipids were measured in HepG2 cells with PFOA and PFOS (<2 μM). Overall, we identified a novel mechanism mediated by transcriptional downregulation of nudt7 gene in hepatocellular lipid increase treated with PFOA and PFOS, which could potentially explain the NAFLD occurrence associated with exposure to PFASs in humans.
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Affiliation(s)
- Xiao Gou
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Mingming Tian
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Lu Yan
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China; College of Water Resource and Environment Engineering, Nanyang Normal University, Nanyang 473061, China
| | - Pu Xia
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Huimin Ji
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Haoyue Tan
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China; Jiangsu Province Ecology and Environment Protection Key Laboratory of Chemical Safety and Health Risk, Nanjing 210023, China
| | - Wei Shi
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China; Jiangsu Province Ecology and Environment Protection Key Laboratory of Chemical Safety and Health Risk, Nanjing 210023, China
| | - Hongxia Yu
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China; Jiangsu Province Ecology and Environment Protection Key Laboratory of Chemical Safety and Health Risk, Nanjing 210023, China
| | - Xiaowei Zhang
- State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, School of the Environment, Nanjing University, Nanjing 210023, China; Jiangsu Province Ecology and Environment Protection Key Laboratory of Chemical Safety and Health Risk, Nanjing 210023, China.
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Ding J, Xu M, Du W, Fang ZQ, Xu H, Liu JJ, Song P, Xu C, Li ZW, Yue ZS, Ling YW, Duan JL, Tao KS, He F, Wang L. Myeloid-specific blockade of Notch signaling ameliorates nonalcoholic fatty liver disease in mice. Int J Biol Sci 2023; 19:1941-1954. [PMID: 37063432 PMCID: PMC10092768 DOI: 10.7150/ijbs.80122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 03/05/2023] [Indexed: 04/18/2023] Open
Abstract
Rationale: Macrophages play a central role in the development and progression of nonalcoholic fatty liver disease (NAFLD). Studies have shown that Notch signaling mediated by transcription factor recombination signal binding protein for immunoglobulin kappa J region (RBP-J), is implicated in macrophage activation and plasticity. Naturally, we asked whether Notch signaling in macrophages plays a role in NAFLD, whether regulating Notch signaling in macrophages could serve as a therapeutic strategy to treat NAFLD. Methods: Immunofluorescence staining was used to detect the changes of macrophage Notch signaling in the livers of human patients with NAFLD and choline deficient amino acid-defined (CDAA) diet-fed mice. Lyz2-Cre RBP-Jflox or wild-type C57BL/6 male mice were fed with CDAA or high fat diet (HFD) to induce experimental steatohepatitis or steatosis, respectively. Liver histology examinations were performed using hematoxylin-eosin (H&E), Oil Red O staining, Sirius red staining and immunohistochemistry staining for F4/80, Col1α1 and αSMA. The expression of inflammatory factors, fibrosis or lipid metabolism associated genes were evaluated by quantitative reverse transcription (qRT)-PCR, Western blot or enzyme-linked immunosorbent assay (ELISA). The mRNA expression of liver samples was profiled by using RNA-seq. A hairpin-type decoy oligodeoxynucleotides (ODNs) for transcription factor RBP-J was loaded into bEnd.3-derived exosomes by electroporating. Mice with experimental NAFLD were treated with exosomes loading RBP-J decoy ODNs via tail vein injection. In vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. Results: The results showed that Notch signaling was activated in hepatic macrophages in human with NAFLD or in CDAA-fed mice. Myeloid-specific RBP-J deficiency decreased the expression of inflammatory factors interleukin-1 beta (IL1β) and tumor necrosis factor alpha (TNFα), attenuated experimental steatohepatitis in mice. Furthermore, we found that Notch blockade attenuated lipid accumulation in hepatocytes by inhibiting the expression of IL1β and TNFα in macrophages in vitro. Meanwhile, we observed that tail vein-injected exosomes were mainly taken up by hepatic macrophages in mice with steatohepatitis. RBP-J decoy ODNs delivered by exosomes could efficiently inhibit Notch signaling in hepatic macrophages in vivo and ameliorate steatohepatitis or steatosis in CDAA or HFD mice, respectively. Conclusions: Combined, macrophage RBP-J promotes the progression of NAFLD at least partially through regulating the expression of pro-inflammatory cytokines IL1β and TNFα. Infusion of exosomes loaded with RBP-J decoy ODNs might be a promising therapy to treat NAFLD.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Kai-Shan Tao
- ✉ Corresponding authors: Kai-Shan Tao (), Fei He (, ORCID: https://orcid.org/0000-0001-8368-5030) and Lin Wang ()
| | - Fei He
- ✉ Corresponding authors: Kai-Shan Tao (), Fei He (, ORCID: https://orcid.org/0000-0001-8368-5030) and Lin Wang ()
| | - Lin Wang
- ✉ Corresponding authors: Kai-Shan Tao (), Fei He (, ORCID: https://orcid.org/0000-0001-8368-5030) and Lin Wang ()
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Vickers SD, Shumar SA, Saporito DC, Kunovac A, Hathaway QA, Mintmier B, King JA, King RD, Rajendran VM, Infante AM, Hollander JM, Leonardi R. NUDT7 regulates total hepatic CoA levels and the composition of the intestinal bile acid pool in male mice fed a Western diet. J Biol Chem 2022; 299:102745. [PMID: 36436558 PMCID: PMC9792899 DOI: 10.1016/j.jbc.2022.102745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/25/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022] Open
Abstract
Nudix hydrolase 7 (NUDT7) is an enzyme that hydrolyzes CoA species, is highly expressed in the liver, and resides in the peroxisomes. Peroxisomes are organelles where the preferential oxidation of dicarboxylic fatty acids occurs and where the hepatic synthesis of the primary bile acids cholic acid and chenodeoxycholic acid is completed. We previously showed that liver-specific overexpression of NUDT7 affects peroxisomal lipid metabolism but does not prevent the increase in total liver CoA levels that occurs during fasting. We generated Nudt7-/- mice to further characterize the role that peroxisomal (acyl-)CoA degradation plays in the modulation of the size and composition of the acyl-CoA pool and in the regulation of hepatic lipid metabolism. Here, we show that deletion of Nudt7 alters the composition of the hepatic acyl-CoA pool in mice fed a low-fat diet, but only in males fed a Western diet does the lack of NUDT7 activity increase total liver CoA levels. This effect is driven by the male-specific accumulation of medium-chain dicarboxylic acyl-CoAs, which are produced from the β-oxidation of dicarboxylic fatty acids. We also show that, under conditions of elevated synthesis of chenodeoxycholic acid derivatives, Nudt7 deletion promotes the production of tauromuricholic acid, decreasing the hydrophobicity index of the intestinal bile acid pool and increasing fecal cholesterol excretion in male mice. These findings reveal that NUDT7-mediated hydrolysis of acyl-CoA pathway intermediates in liver peroxisomes contributes to the regulation of dicarboxylic fatty acid metabolism and the composition of the bile acid pool.
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Affiliation(s)
- Schuyler D Vickers
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Stephanie A Shumar
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Dominique C Saporito
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Amina Kunovac
- Division of Exercise Physiology, West Virginia University, Morgantown, West Virginia, USA
| | - Quincy A Hathaway
- Division of Exercise Physiology, West Virginia University, Morgantown, West Virginia, USA
| | - Breeanna Mintmier
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Judy A King
- Department of Pathology and Translational Pathobiology, LSU Health Shreveport, Shreveport, Louisiana, USA
| | - Rachel D King
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Vazhaikkurichi M Rajendran
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Aniello M Infante
- Genomics Core Facility, West Virginia University, Morgantown, West Virginia, USA
| | - John M Hollander
- Division of Exercise Physiology, West Virginia University, Morgantown, West Virginia, USA
| | - Roberta Leonardi
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA.
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