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Cai Q, Li Y, Chang YF, Tang Z, Zhang H, Xie Q. Pasteurella multocida causes liver injury in ducks by mediating inflammatory, apoptotic and autophagic pathways. Microb Pathog 2023; 184:106336. [PMID: 37683832 DOI: 10.1016/j.micpath.2023.106336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/16/2023] [Accepted: 09/04/2023] [Indexed: 09/10/2023]
Abstract
Pasteurella multocida.(PM) infection is a major cause of avian cholera, but the pathogenesis of the disease is unknown. The purpose of this study was to further understand the host response to infection by using a duck model of PM, 20 female ducks were divided into two groups (n = 10). One group was infected with PM, while the other served as an uninfected control group. The ducks were observed after infection and samples were collected for testing. In this study, we report the mechanism of PM-induced inflammation to further mediate apoptosis and autophagic signaling pathways in liver cells. Our results demonstrated that PM infection initially induces hemorrhagic and necrotic lesions in the liver tissue of duck, promoting inflammasome assembly and release, triggering inflammation. The TLR4/NF-κB axis activated and interacted with multiple inflammation-related proteins, including TNF-α and IL-1β, which affected apoptosis and autophagy. Tumor necrosis factor induced hepatocyte apoptosis was implicated in a wide range of liver diseases; the release of TNF-α and activation with NF-κB further incite apoptotic pathways,such as Bax/BCL2/caspase to promote apoptotic genes APAF1, Bax, Caspase3, BCL-2, p53, and Cytc expression. Finally, PM-induced autophagy suppressed liver injury by promoting the Beclin-1, LC3B, p62, and mTOR. Thus, liver injury caused by PM via promoting autophagy was induced. In conclusion, we analyzed the liver injury of ducks infected with PM, and confirmed that inflammation appeared in the liver; this was followed by the intricate interplay between inflammation, apoptosis, and autophagy signaling pathways. The observed results provided a reference basis for studying pathogenic mechanisms of PM-host interactions.
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Affiliation(s)
- Qiuxiang Cai
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Yajuan Li
- College of Animal Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Yung-Fu Chang
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
| | - Zhaoxin Tang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Hui Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.
| | - Qingmei Xie
- College of Animal Sciences, South China Agricultural University, Guangzhou, 510642, China
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2
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Rani R, Gandhi CR. Stellate cell in hepatic inflammation and acute injury. J Cell Physiol 2023; 238:1226-1236. [PMID: 37120832 DOI: 10.1002/jcp.31029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 05/02/2023]
Abstract
The perisinusoidal hepatic stellate cells (HSCs) have been investigated extensively for their role as the major fibrogenic cells during chronic liver injury. HSCs also produce numerous cytokines, chemokines, and growth mediators, and express cell adhesion molecules constitutively and in response to stimulants such as endotoxin (lipopolysaccharide). With this property and by interacting with resident and recruited immune and inflammatory cells, HSCs regulate hepatic immune homeostasis, inflammation, and acute injury. Indeed, experiments with HSC-depleted animal models and cocultures have provided evidence for the prominent role of HSCs in the initiation and progression of inflammation and acute liver damage due to various toxic agents. Thus HSCs and/or mediators derived thereof during acute liver damage may be considered as potential therapeutic targets.
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Affiliation(s)
- Richa Rani
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Research & Development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio, USA
| | - Chandrashekhar R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Research & Development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio, USA
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA
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3
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Rani R, Sharma A, Wang J, Kumar S, Polaki US, Gandhi CR. Endotoxin-Stimulated Hepatic Stellate Cells Augment Acetaminophen-Induced Hepatocyte Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:518-535. [PMID: 34954210 PMCID: PMC8895430 DOI: 10.1016/j.ajpath.2021.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/27/2021] [Accepted: 11/29/2021] [Indexed: 12/11/2022]
Abstract
Acetaminophen (APAP)-induced liver injury is influenced by inflammatory Gram-negative bacterial endotoxin [lipopolysaccharide (LPS)], mechanisms of which are not completely understood. Because LPS-stimulated perisinusoidal hepatic stellate cells (HSCs) produce cytokines that affect survival of hepatocytes, this study investigated their role in APAP-induced liver injury. Fed (nonstarved) rats were administered 5 mg/kg LPS or phosphate-buffered saline (PBS) vehicle, followed by 200 mg/kg APAP or PBS an hour later, and euthanized at 6 hours. Control rats received PBS at both time points. Both LPS and APAP caused mild hepatocyte injury (apoptosis), as assessed by histopathology, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and caspase-3 activation. The liver injury was augmented in rats administered LPS + APAP, in association with increased nuclear translocation of interferon-regulatory factor-1 (IRF1). In vitro, APAP augmented LPS/HSC-conditioned medium-induced inhibition of DNA and protein synthesis, apoptosis, and nuclear IRF1 in hepatocytes. LPS-stimulated HSCs produced interferon-β (IFN-β), and LPS/HSC + APAP-induced hepatocyte apoptosis was inhibited by anti-IFN-β antibody. Finally, HSC-depleted mice produced significantly lower IFN-β and tumor necrosis factor-α, exhibited less oxidative stress, and were protected from excessive injury due to high APAP dose (600 mg/kg), as well as LPS (5 mg/kg overnight) followed by APAP. In co-culture with or without LPS, HSCs increased expression of proinflammatory cytokines by Kupffer cells. These results suggest that HSCs play a critical role in APAP-induced liver injury without or with LPS preconditioning, and it involves INF-β-IRF1 signaling.
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Affiliation(s)
- Richa Rani
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Akanksha Sharma
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology, University of Cincinnati, Cincinnati, Ohio
| | - Sudhir Kumar
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Usha S Polaki
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Chandrashekhar R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
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4
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Bi X, Yang N, Ke Y, Liu H, Ma W, Fang B, Sun L, Li L, Lü G, Lin R. An improved experimental method for simultaneously isolating hepatocytes and hepatic stellate cells in mouse liver infected with Echinococcus multilocularis. J Clin Lab Anal 2021; 35:e24084. [PMID: 34724252 PMCID: PMC8649337 DOI: 10.1002/jcla.24084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 09/24/2021] [Accepted: 10/20/2021] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Alveolar echinococcosis (AE) is a zoonotic disease caused by the larval stage of Echinococcus multilocularis parasitizing in the human liver, causing local pathological changes in the liver and manifesting as hyperplasia, liver fibrosis, atrophy, degeneration, and necrosis. Here, we report a method that can simultaneously isolate hepatocytes and hepatic stellate cells (HSCs) from mice infected with Echinococcus multilocularis. METHODS A mouse model of AE was established. Hepatocytes and HSCs were isolated from mouse liver using a two-step method combining in situ collagenase perfusion and gradient centrifugation. Expressions of Alb, Desmin, and α-SMA were detected with immunofluorescence to identify the isolated hepatocytes and HSCs. RESULTS The viability and purity of hepatocytes and HSCs both reached 90% or above. For hepatocytes, clear cell boundaries were observed, and the nuclei were round or oval, with clear nucleoli. There was a homogeneous distribution of the hepatocyte marker Alb in the cytoplasm of hepatocytes. Lipid droplets and Desmin expression were observed in the cytoplasm of freshly isolated HSCs. During the activation of HSCs, the lipid droplets gradually decreased and disappeared with a high expression of α-SMA. CONCLUSION Hepatocytes and HSCs are simultaneously isolated. This may provide a research tool to investigate the interaction between hepatocytes and HSCs and to investigate the mechanism of Echinococcus multilocularis infection-induced liver pathological changes.
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Affiliation(s)
- Xiaojuan Bi
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Ning Yang
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Ying Ke
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Hui Liu
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Wenmei Ma
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Bingbing Fang
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Li Sun
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Liang Li
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
| | - Guodong Lü
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
- Department of Epidemiology and Health StatisticsSchool of Public HealthXinjiang Medical UniversityUrumqiChina
| | - Renyong Lin
- State Key Laboratory of PathogenesisPrevention, and Treatment of Central Asian High Incidence DiseasesClinical Medical Research InstituteThe First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina
- Basic Medical CollegeXinjiang Medical UniversityUrumqiChina
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Sufleţel RT, Melincovici CS, Gheban BA, Toader Z, Mihu CM. Hepatic stellate cells - from past till present: morphology, human markers, human cell lines, behavior in normal and liver pathology. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY 2021; 61:615-642. [PMID: 33817704 PMCID: PMC8112759 DOI: 10.47162/rjme.61.3.01] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hepatic stellate cell (HSC), initially analyzed by von Kupffer, in 1876, revealed to be an extraordinary mesenchymal cell, essential for both hepatocellular function and lesions, being the hallmark of hepatic fibrogenesis and carcinogenesis. Apart from their implications in hepatic injury, HSCs play a vital role in liver development and regeneration, xenobiotic response, intermediate metabolism, and regulation of immune response. In this review, we discuss the current state of knowledge regarding HSCs morphology, human HSCs markers and human HSC cell lines. We also summarize the latest findings concerning their roles in normal and liver pathology, focusing on their impact in fibrogenesis, chronic viral hepatitis and liver tumors.
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Affiliation(s)
- Rada Teodora Sufleţel
- Discipline of Histology, Department of Morphological Sciences, Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania;
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Yusuf IO, Chen HM, Cheng PH, Chang CY, Tsai SJ, Chuang JI, Wu CC, Huang BM, Sun HS, Chen CM, Yang SH. FGF9 induces neurite outgrowth upon ERK signaling in knock-in striatal Huntington's disease cells. Life Sci 2020; 267:118952. [PMID: 33383048 DOI: 10.1016/j.lfs.2020.118952] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/17/2022]
Abstract
AIMS Huntington's disease (HD) is a neurodegenerative disease that causes deficits in neurite outgrowth, which suggests that enhancement of neurite outgrowth is a potential direction by which to improve HD. Our previous publications showed that fibroblast growth factor 9 (FGF9) provides anti-apoptosis and anti-oxidative functions in striatal cell models of HD through the extracellular signal-regulated kinases (ERK) pathway, and FGF9 also stimulates cytoskeletons to enhance neurite outgrowth via nuclear factor kappa B (NF-kB) signaling. In this study, we further demonstrate the importance of the ERK pathway for the neurite outgrowth induced by FGF9 in HD striatal models. MATERIALS AND METHODS FGF9 was treated with ERK (U0126) or NF-kB (BAY11-7082) inhibitors in STHdhQ7/Q7 and STHdhQ111/Q111 striatal knock-in cell lines to examine neurite outgrowth, cytoskeletal markers, and synaptic proteins via immunofluorescence staining and Western blotting. NF-kB activity was analyzed by NF-kB promoter reporter assay. KEY FINDINGS Here, we show that suppression of ERK signaling significantly inhibits FGF9-induced neurite outgrowth, cytoskeletal markers, and synaptic proteins in HD striatal cells. In addition, we also show suppression of ERK signaling significantly decreases FGF9-induced NF-kB activation, whereas suppression of NF-kB does not decrease FGF9-induced ERK signaling. These results suggest that FGF9 activates ERK signaling first, stimulates NF-kB upregulation, and then enhances neurite outgrowth in HD striatal cells. SIGNIFICANCE We elucidate the more detailed mechanisms of neurite outgrowth enhanced by FGF9 in these HD striatal cells. This study may provide insights into targeting neurite outgrowth for HD therapy.
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Affiliation(s)
- Issa Olakunle Yusuf
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University and Academia Sinica, Taipei 11529, Taiwan; Institute of Clinical Medicine, College of Medicine, Taiwan; Department of Physiology, College of Medicine, Taiwan
| | - Hsiu-Mei Chen
- Department of Physiology, College of Medicine, Taiwan
| | | | - Chih-Yi Chang
- Department of Physiology, College of Medicine, Taiwan
| | - Shaw-Jenq Tsai
- Department of Physiology, College of Medicine, Taiwan; Institute of Basic Medical Sciences, Taiwan
| | - Jih-Ing Chuang
- Department of Physiology, College of Medicine, Taiwan; Institute of Basic Medical Sciences, Taiwan
| | - Chia-Ching Wu
- Institute of Basic Medical Sciences, Taiwan; Department of Cell Biology and Anatomy, Taiwan
| | - Bu-Miin Huang
- Institute of Basic Medical Sciences, Taiwan; Department of Cell Biology and Anatomy, Taiwan
| | - H Sunny Sun
- Institute of Basic Medical Sciences, Taiwan; Institute of Molecular Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chuan-Mu Chen
- Department of Life Sciences, College of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan
| | - Shang-Hsun Yang
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University and Academia Sinica, Taipei 11529, Taiwan; Department of Physiology, College of Medicine, Taiwan; Institute of Basic Medical Sciences, Taiwan.
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7
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Gandhi CR. Pro- and Anti-fibrogenic Functions of Gram-Negative Bacterial Lipopolysaccharide in the Liver. Front Med (Lausanne) 2020; 7:130. [PMID: 32373617 PMCID: PMC7186417 DOI: 10.3389/fmed.2020.00130] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/24/2020] [Indexed: 12/14/2022] Open
Abstract
Extensive research performed over several decades has identified cells participating in the initiation and progression of fibrosis, and the numerous underlying inter- and intra-cellular signaling pathways. However, liver fibrosis continues to be a major clinical challenge as the precise targets of treatment are still elusive. Activation of physiologically quiescent perisinusoidal hepatic stellate cells (HSCs) to a myofibroblastic proliferating, contractile and fibrogenic phenotype is a critical event in the pathogenesis of chronic liver disease. Thus, elucidation of the mechanisms of the reversal to quiescence or inhibition of activated HSCs, and/or their elimination via apoptosis has been the focus of intense investigation. Lipopolysaccharide (LPS), a gut-resident Gram-negative bacterial endotoxin, is a powerful pro-inflammatory molecule implicated in hepatic injury, inflammation and fibrosis. In both acute and chronic liver injury, portal venous levels of LPS are elevated due to increased intestinal permeability. LPS, via CD14 and Toll-like receptor 4 (TLR4) and its adapter molecules, stimulates macrophages, neutrophils and several other cell types to produce inflammatory mediators as well as factors that can activate HSCs and stimulate their fibrogenic activity. LPS also stimulates synthesis of pro- and anti-inflammatory cytokines/chemokines, growth mediators and molecules of immune regulation by HSCs. However, LPS was found to arrest proliferation of activated HSCs and to convert them into non-fibrogenic phenotype. Interestingly, LPS can elicit responses in HSCs independent of CD14 and TLR4. Identifying and/or developing non-inflammatory but anti-fibrogenic mimetics of LPS could be relevant for treating liver fibrosis.
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Affiliation(s)
- Chandrashekhar R Gandhi
- Divisions of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Cincinnati VA Medical Center, Cincinnati, OH, United States
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Kostallari E, Shah VH. Pericytes in the Liver. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1122:153-167. [PMID: 30937868 DOI: 10.1007/978-3-030-11093-2_9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Liver pericytes, commonly named hepatic stellate cells (HSCs), reside in the space between liver sinusoidal endothelial cells (LSECs) and hepatocytes. They display important roles in health and disease. HSCs ensure the storage of the majority of vitamin A in a healthy body, and they represent the major source of fibrotic tissue in liver disease. Surrounding cells, such as LSECs, hepatocytes, and Kupffer cells, present a significant role in modulating HSC behavior. Therapeutic strategies against liver disease are being currently developed, where HSCs represent an ideal target. In this chapter, we will discuss HSC quiescence and activation in the context of healthy liver and diseases, such as fibrosis, steatohepatitis, and hepatocellular carcinoma.
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Affiliation(s)
- Enis Kostallari
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Vijay H Shah
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.
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9
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Dhar SK, Batinic-Haberle I, St Clair DK. UVB-induced inactivation of manganese-containing superoxide dismutase promotes mitophagy via ROS-mediated mTORC2 pathway activation. J Biol Chem 2019; 294:6831-6842. [PMID: 30858178 DOI: 10.1074/jbc.ra118.006595] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 03/05/2019] [Indexed: 12/23/2022] Open
Abstract
Mitochondria are major sites of energy metabolism that influence numerous cellular events, including immunity and cancer development. Previously, we reported that the mitochondrion-specific antioxidant enzyme, manganese-containing superoxide dismutase (MnSOD), has dual roles in early- and late-carcinogenesis stages. However, how defective MnSOD impacts the chain of events that lead to cell transformation in pathologically normal epidermal cells that have been exposed to carcinogens is unknown. Here, we show that UVB radiation causes nitration and inactivation of MnSOD leading to mitochondrial injury and mitophagy. In keratinocytes, exposure to UVB radiation decreased mitochondrial oxidative phosphorylation, increased glycolysis and the expression of autophagy-related genes, and enhanced AKT Ser/Thr kinase (AKT) phosphorylation and cell growth. Interestingly, UVB initiated a prosurvival mitophagy response by mitochondria-mediated reactive oxygen species (ROS) signaling via the mammalian target of the mTOR complex 2 (mTORC2) pathway. Knockdown of rictor but not raptor abrogated UVB-induced mitophagy responses. Furthermore, fractionation and proximity-ligation assays reveal that ROS-mediated mTOC2 activation in mitochondria is necessary for UVB-induced mitophagy. Importantly, pretreatment with the MnSOD mimic MnTnBuOE-2-PyP5+ (MnP) attenuates mTORC2 activation and suppresses UVB-induced mitophagy. UVB radiation exposure also increased cell growth as assessed by soft-agar colony survival and cell growth assays, and pretreatment with MnP or the known autophagy inhibitor 3-methyladenine abrogated UVB-induced cell growth. These results indicate that MnSOD is a major redox regulator that maintains mitochondrial health and show that UVB-mediated MnSOD inactivation promotes mitophagy and thereby prevents accumulation of damaged mitochondria.
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Affiliation(s)
- Sanjit K Dhar
- From the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40536 and
| | - Ines Batinic-Haberle
- the Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - Daret K St Clair
- From the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40536 and
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10
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Rani R, Kumar S, Sharma A, Mohanty SK, Donnelly B, Tiao GM, Gandhi CR. Mechanisms of concanavalin A-induced cytokine synthesis by hepatic stellate cells: Distinct roles of interferon regulatory factor-1 in liver injury. J Biol Chem 2018; 293:18466-18476. [PMID: 30348900 DOI: 10.1074/jbc.ra118.005583] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/15/2018] [Indexed: 12/26/2022] Open
Abstract
Mice depleted of hepatic stellate cells (HSCs) are protected from concanavalin A (ConA)-induced liver injury that is mediated by the activation of interferon regulatory factor 1 (IRF1). The aim of this study was to determine the mechanisms of ConA-mediated signaling and synthesis/release of mediators by HSCs that damage hepatocytes. Primary cultures of wildtype (WT) and IRF1-knockout (KO) HSCs and hepatocytes were used, and ConA-induced liver damage in interferon (IFN)αβ receptor-deficient (IFNαβR-KO) mice was determined. Specific binding of ConA to HSCs induced rapid activation of JAK2 and STAT1. ConA-induced expression of IRF1, IFNβ, tumor necrosis factor α, and CXCL1 was abrogated by selective inhibition of JAK2 and STAT1. Despite activating JAK2/STAT1, ConA failed to stimulate expression of inflammatory cytokines in HSCs from IRF1-KO mice. ConA-conditioned WT-HSC medium caused activation of JNK and caspase 3, and apoptosis of hepatocytes from WT but not from IRF1-KO or IFNαβR-KO mice. Conversely, ConA-conditioned medium of IRF1-KO HSCs failed to cause apoptosis of WT or IRF1-KO hepatocytes. IFNαβR-KO mice were protected from ConA-induced liver damage, and ConA-induced hepatic expression of IRF1 and pro-inflammatory cytokines and chemokines, and infiltration of neutrophils were significantly lower in IFNαβR-KO than in WT mice. These results demonstrate distinct roles of IRF1 in hepatic inflammation (HSCs) and injury (hepatocytes) and can be an important target for intervention in acute liver injury.
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Affiliation(s)
- Richa Rani
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229.,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and
| | - Sudhir Kumar
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229.,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and
| | - Akanksha Sharma
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Sujit K Mohanty
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Bryan Donnelly
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Gregory M Tiao
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Chandrashekhar R Gandhi
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, .,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and.,the Department of Surgery, University of Cincinnati, Cincinnati, Ohio 45220
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11
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Dhar SK, Bakthavatchalu V, Dhar B, Chen J, Tadahide I, Zhu H, Gao T, St Clair DK. DNA polymerase gamma (Polγ) deficiency triggers a selective mTORC2 prosurvival autophagy response via mitochondria-mediated ROS signaling. Oncogene 2018; 37:6225-6242. [PMID: 30038268 PMCID: PMC6265263 DOI: 10.1038/s41388-018-0404-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/30/2018] [Accepted: 06/11/2018] [Indexed: 11/24/2022]
Abstract
Autophagy is a highly regulated evolutionarily conserved metabolic process induced by stress and energy deprivation. Here, we show that DNA polymerase gamma (Polγ) deficiency activates a selective prosurvival autophagic response via mitochondria-mediated reactive oxygen species (ROS) signaling and the mammalian target of rapamycin complex 2 (mTORC2) activities. In keratinocytes, Polγ deficiency causes metabolic adaptation that triggers cytosolic sensing of energy demand for survival. Knockdown of Polγ causes mitochondrial stress, decreases mitochondrial energy production, increases glycolysis, increases the expression of autophagy-associated genes, and enhances AKT phosphorylation and cell proliferation. Deficiency of Polγ preferentially activates mTORC2 formation to increase autophagy and cell proliferation, and knocking down Rictor abrogates these responses. Overexpression of Rictor, but not Raptor, reactivates autophagy in Polγ-deficient cells. Importantly, inhibition of ROS by a mitochondria-selective ROS scavenger abolishes autophagy and cell proliferation. These results identify Rictor as a critical link between mitochondrial stress, ROS, and autophagy. They represent a major shift in our understanding of the prosurvival role of the mTOR complexes and highlight mitochondria-mediated ROS as a prosurvival autophagy regulator during cancer development.
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Affiliation(s)
- Sanjit K Dhar
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, 40536, USA
| | - Vasudevan Bakthavatchalu
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Bithika Dhar
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, 40536, USA
| | - Jing Chen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA
| | - Izumi Tadahide
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, 40536, USA
| | - Haining Zhu
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA
| | - Tianyan Gao
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA
| | - Daret K St Clair
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, 40536, USA.
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12
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Vodovotz Y, Simmons RL, Gandhi CR, Barclay D, Jefferson BS, Huang C, Namas R, El-Dehaibi F, Mi Q, Billiar TR, Zamora R. "Thinking" vs. "Talking": Differential Autocrine Inflammatory Networks in Isolated Primary Hepatic Stellate Cells and Hepatocytes under Hypoxic Stress. Front Physiol 2017; 8:1104. [PMID: 29312006 PMCID: PMC5743931 DOI: 10.3389/fphys.2017.01104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/14/2017] [Indexed: 12/23/2022] Open
Abstract
We hypothesized that isolated primary mouse hepatic stellate cells (HSC) and hepatocytes (HC) would elaborate different inflammatory responses to hypoxia with or without reoxygenation. We further hypothesized that intracellular information processing (“thinking”) differs from extracellular information transfer (“talking”) in each of these two liver cell types. Finally, we hypothesized that the complexity of these autocrine responses might only be defined in the absence of other non-parenchymal cells or trafficking leukocytes. Accordingly, we assayed 19 inflammatory mediators in the cell culture media (CCM) and whole cell lysates (WCLs) of HSC and HC during hypoxia with and without reoxygenation. We applied a unique set of statistical and data-driven modeling techniques including Two-Way ANOVA, hierarchical clustering, Principal Component Analysis (PCA) and Network Analysis to define the inflammatory responses of these isolated cells to stress. HSC, under hypoxic and reoxygenation stresses, both expressed and secreted larger quantities of nearly all inflammatory mediators as compared to HC. These differential responses allowed for segregation of HSC from HC by hierarchical clustering. PCA suggested, and network analysis supported, the hypothesis that above a certain threshold of cellular stress, the inflammatory response becomes focused on a limited number of functions in both HSC and HC, but with distinct characteristics in each cell type. Network analysis of separate extracellular and intracellular inflammatory responses, as well as analysis of the combined data, also suggested the presence of more complex inflammatory “talking” (but not “thinking”) networks in HSC than in HC. This combined network analysis also suggested an interplay between intracellular and extracellular mediators in HSC under more conditions than that observed in HC, though both cell types exhibited a qualitatively similar phenotype under hypoxia/reoxygenation. Our results thus suggest that a stepwise series of computational and statistical analyses may help decipher how cells respond to environmental stresses, both within the cell and in its secretory products, even in the absence of cooperation from other cells in the liver.
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Affiliation(s)
- Yoram Vodovotz
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Richard L Simmons
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Derek Barclay
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Chao Huang
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Rami Namas
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Fayten El-Dehaibi
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Qi Mi
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Timothy R Billiar
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ruben Zamora
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
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13
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Dong G, Si C, Zhang Q, Yan F, Li C, Zhang H, Ma Q, Dai J, Li Z, Shi H, Wang B, Zhang J, Ming J, Hu Y, Geng S, Zhang Y, Li L, Xiong H. Autophagy regulates accumulation and functional activity of granulocytic myeloid-derived suppressor cells via STAT3 signaling in endotoxin shock. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2796-2807. [DOI: 10.1016/j.bbadis.2017.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 08/05/2017] [Accepted: 08/08/2017] [Indexed: 12/11/2022]
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14
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Abstract
Recent research indicates crucial roles of autophagy during sepsis. In animal models of sepsis induced by cecal ligation and puncture (CLP) or the systemic administration of lipopolysaccharides (LPS), autophagy is implicated in the activation and/or damage of various cells/organs, such as immune cells, heart, lung, kidney, and liver. Since sepsis is associated with an increased production of pro- as well as anti-inflammatory cytokines, it has long been considered that hypercytokinemia is a fetal immune response leading to multiple organ failure (MOF) and mortality of humans during sepsis. However, a recent paradigm illuminates the crucial roles of mitochondrial dysfunction as well as the perturbation of autophagy in the pathogenesis of sepsis. In the livers of animal models of sepsis, autophagy is involved in the elimination of damaged mitochondria to prevent the generation of mitochondrial ROS and the initiation of the mitochondrial apoptotic pathway. In addition, many reports now indicate that the role of autophagy is not restricted to the elimination of hazardous malfunctioning mitochondria within the cells; autophagy has been shown to be involved in the regulation of inflammasome activation and the release of cytokines as well as other inflammatory substances. In this review, we summarize recent literature describing the versatile role of autophagy and its possible implications in the pathogenesis of sepsis in the liver.
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Affiliation(s)
- Toshihiko Aki
- Department of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Kana Unuma
- Department of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Koichi Uemura
- Department of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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15
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Rani R, Tandon A, Wang J, Kumar S, Gandhi CR. Stellate Cells Orchestrate Concanavalin A-Induced Acute Liver Damage. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2008-2019. [PMID: 28710903 DOI: 10.1016/j.ajpath.2017.05.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/13/2017] [Accepted: 05/22/2017] [Indexed: 12/12/2022]
Abstract
Concanavalin A (ConA) causes immune cell-mediated liver damage, but the contribution of resident nonparenchymal cells (NPCs) is also evident. Hepatic stellate cells (HSCs) induce hepatic inflammation and immunological reactions; we therefore investigated their role in ConA-induced liver injury. ConA was administered i.v. to control or HSC-depleted mice; hepatic histopathology and cytokines/chemokines were determined after 6 hours. In vitro, effects of ConA-conditioned HSC medium on hepatocytes were determined. ConA induced inflammation, sinusoidal congestion, and extensive midzonal hepatocyte death in control mice, which were strongly minimized in HSC-depleted mice. CD4 and natural killer T cells and neutrophils were markedly reduced in ConA-treated HSC-depleted mice compared with control mice. The increase in cytokines/chemokines of hepatic injury was much higher in ConA-treated control mice than in HSC-depleted mice. ConA-treated HSCs showed increased expression of interferon-β, tumor necrosis factor-α, and CXCL1, induced oxidative stress in hepatocytes, and caused hepatocyte apoptosis. ConA induced nuclear translocation of interferon-regulatory factor-1 (IRF1) in hepatocytes in vivo, and ConA/HSC induced a similar effect in cultured hepatocytes. IRF1-knockout mice were resistant to ConA-induced liver damage, and anti-interferon β antibody mitigated ConA/HSC-induced injury. In HSC-NPC co-culture, ConA-induced expression of inflammatory cytokines/chemokines was significantly augmented compared with NPCs alone. HSCs play an essential role in ConA-induced liver injury directly via the interferon-β/IRF1 axis, and by modulating properties of NPCs.
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Affiliation(s)
- Richa Rani
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ashish Tandon
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology, University of Cincinnati, Cincinnati, Ohio
| | - Sudhir Kumar
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Chandrashekhar R Gandhi
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
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16
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Paracrine Effects of Bone Marrow Mononuclear Cells in Survival and Cytokine Expression after 90% Partial Hepatectomy. Stem Cells Int 2017; 2017:5270527. [PMID: 28326105 PMCID: PMC5343266 DOI: 10.1155/2017/5270527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/30/2016] [Accepted: 01/10/2017] [Indexed: 12/13/2022] Open
Abstract
Acute liver failure is a complex and fatal disease. Cell-based therapies are a promising alternative therapeutic approach for liver failure due to relatively simple technique and lower cost. The use of semipermeable microcapsules has become an interesting tool for evaluating paracrine effects in vivo. In this study, we aimed to assess the paracrine effects of bone marrow mononuclear cells (BMMC) encapsulated in sodium alginate to treat acute liver failure in an animal model of 90% partial hepatectomy (90% PH). Encapsulated BMMC were able to increase 10-day survival without enhancing liver regeneration markers. Gene expression of Il-6 and Il-10 in the remnant liver was markedly reduced at 6 h after 90% PH in animals receiving encapsulated BMMC compared to controls. This difference, however, was neither reflected by changes in the number of CD68+ cells nor by serum levels of IL6. On the other hand, treated animals presented increased caspase activity and gene expression in the liver. Taken together, these results suggest that BMMC regulate immune response and promote apoptosis in the liver after 90% PH by paracrine factors. These changes ultimately may be related to the higher survival observed in treated animals, suggesting that BMMC may be a promising alternative to treat acute liver failure.
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17
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El-Tanbouly GS, El-Awady MS, Megahed NA, El-Kashef HA, Salem HA. The lipoxin A 4 agonist BML-111 attenuates acute hepatic dysfunction induced by cecal ligation and puncture in rats. Naunyn Schmiedebergs Arch Pharmacol 2016; 390:361-368. [PMID: 28035464 DOI: 10.1007/s00210-016-1335-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/21/2016] [Indexed: 12/11/2022]
Abstract
Sepsis is a systemic inflammatory response associating severe infection leading to multi-organ failure, such as hepatic dysfunction. This study investigates the possible hepatoprotective effect of the lipoxin A4 agonist (BML-111) in cecal ligation and puncture (CLP) model in rats. Pretreatment with BML-111 (1 mg/kg, i.p., 1 h before CLP) protected against CLP-induced mortality after 24 h. BML-111 prevented marked inflammatory cells in liver tissues and decreased elevation in serum hepatic biomarkers [alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), gamma-glutamyl transferase (γ-GT)] induced by CLP. Additionally, BML-111 attenuated elevated serum level of interleukin-6 (IL-6) and downregulated hepatic IL-6 mRNA expression. Meanwhile, BML-111 further increased serum IL-10 and upregulated hepatic IL-10 mRNA expression, while it downregulated hepatic mRNA expression of nuclear factor inhibitory protein kappa-B alpha (NFκBia), toll-like receptor-4 (TLR-4), and 5-lipooxygenase (5-LOX). Moreover, BML-111 prevented NF-κB/p65 nuclear translocation and activation. In conclusion, BML-111 attenuated CLP-induced acute hepatic dysfunction through its anti-inflammatory effect by decreasing NF-κB activity, TLR-4, and 5-LOX expression with subsequent decrease in pro-inflammatory IL-6 and elevation in anti-inflammatory IL-10.
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Affiliation(s)
- Ghada S El-Tanbouly
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
| | - Mohammed S El-Awady
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
| | - Nermeen A Megahed
- Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Hassan A El-Kashef
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Hatem A Salem
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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18
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Yin JJ, Xie G, Zhang N, Li Y. Inhibiting autophagy promotes endoplasmic reticulum stress and the ROS‑induced nod‑like receptor 3‑dependent proinflammatory response in HepG2 cells. Mol Med Rep 2016; 14:3999-4007. [PMID: 27600251 DOI: 10.3892/mmr.2016.5708] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 08/09/2016] [Indexed: 11/06/2022] Open
Abstract
Inflammation and endoplasmic reticulum (ER) stress are key contributors to insulin resistance and metabolic disease, and interleukin (IL)‑1β is involved in insulin resistance. The present study aimed to investigated the role of autophagy in LPS‑induced ER stress and inflammation, which may provide evidence for controlling metabolic disease associated with inflammation. Lipopolysaccharide (LPS) induced the activation of ER stress and the nod‑like receptor 3‑dependent expression of IL‑1β and caspase‑1, as shown by western blotting, which contributed to HepG2 cell death. This also involved the generation of mitochondrial reactive oxygen species and the autophagy signaling response, which are derived from the ER stress pathway. The percentage of apoptotic cells was measured by flow cytometry with fluorescein isothiocyanate/propidium iodide staining. Reactive oxygen species formation was detected by flow cytometry using the peroxide sensitive fluorescent probe 2',7'‑dichlorofluorescin diacetate. Autophagy activation was measured by western blotting and confirmed using transmission electron microscopy. Furthermore, inhibiting autophagy promoted ER stress and the proinflammatory response in addition to cell death. These findings provide insights into the protective role of autophagy in LPS‑induced cell death and ER stress, and further identified the association of autophagy, ER stress and inflammation in HepG2 cells.
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Affiliation(s)
- Jia-Jing Yin
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Guangying Xie
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Ning Zhang
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Yanbo Li
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
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19
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Molecular mechanism of hepatic steatosis: pathophysiological role of autophagy. Expert Rev Mol Med 2016; 18:e14. [PMID: 27499351 DOI: 10.1017/erm.2016.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
UNLABELLED Steatosis is an early characteristic in the pathogenesis of fatty liver disease (FLD). Mechanisms of hepatic steatosis are aetiology-dependent. Activation of autophagy in liver ameliorates hepatic steatosis. A modulation of hepatic autophagy affects the degree of hepatocyte steatosis and the progression of FLD as demonstrated by pre-clinical models and clinical trials. This review summarises recent advances on pathophysiological roles of autophagy in hepatic lipid metabolism. A comprehensive regulation of autophagic networks holds promise for the improvement of hepatic steatosis. Autophagic signalling pathway may be a novel therapeutic target against FLD. HIGHLIGHTS • Hepatic steatosis is a pathological condition wherein vacuoles of triglyceride (TG) fat are overaccumulated in liver because of abnormal metabolism of lipids. • Hepatic autophagy regulates lipid metabolism as demonstrated by macrolipophagy in response to starvation and hepatic overabundance of TG in obesity. • Autophagic signals are closely associated with apoptotic pathways. There is distinctive relationship between hepatic autophagy and apoptosis, which affects the progression of fatty liver. • Regulation of autophagic process can be a novel therapeutic strategy for fatty liver disease.
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