Browsing by Author "Yang, Zhihong"

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    Alcohol Metabolizing Enzymes, Microsomal Ethanol Oxidizing System, Cytochrome P450 2E1, Catalase, and Aldehyde Dehydrogenase in Alcohol-Associated Liver Disease
    (MDPI, 2020-03) Jiang, Yanchao; Zhang, Ting; Kusumanchi, Praveen; Han, Sen; Yang, Zhihong; Liangpunsakul, Suthat; Medicine, School of Medicine
    Once ingested, most of the alcohol is metabolized in the liver by alcohol dehydrogenase to acetaldehyde. Two additional pathways of acetaldehyde generation are by microsomal ethanol oxidizing system (cytochrome P450 2E1) and catalase. Acetaldehyde can form adducts which can interfere with cellular function, leading to alcohol-induced liver injury. The variants of alcohol metabolizing genes encode enzymes with varied kinetic properties and result in the different rate of alcohol elimination and acetaldehyde generation. Allelic variants of these genes with higher enzymatic activity are believed to be able to modify susceptibility to alcohol-induced liver injury; however, the human studies on the association of these variants and alcohol-associated liver disease are inconclusive. In addition to acetaldehyde, the shift in the redox state during alcohol elimination may also link to other pathways resulting in activation of downstream signaling leading to liver injury.
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    Alcohol-induced gut microbial reorganization and associated overproduction of phenylacetylglutamine promotes cardiovascular disease
    (Springer Nature, 2024-12-30) Li, Zhen; Gu, Min; Zaparte, Aline; Fu, Xiaoming; Mahen, Kala; Mrdjen, Marko; Li, Xinmin S.; Yang, Zhihong; Ma, Jing; Thoudam, Themis; Chandler, Kristina; Hesler, Maggie; Heathers, Laura; Gorse, Kiersten; Van, Thanh Trung; Wong, David; Gibson, Aaron M.; Wang, Zeneng; Taylor, Christopher M.; Quijada, Pearl; Makarewich, Catherine A.; Hazen, Stanley L.; Liangpunsakul, Suthat; Brown, J. Mark; Lefer, David J.; Welsh, David A.; Sharp, Thomas E., III; Medicine, School of Medicine
    The mechanism(s) underlying gut microbial metabolite (GMM) contribution towards alcohol-mediated cardiovascular disease (CVD) is unknown. Herein we observe elevation in circulating phenylacetylglutamine (PAGln), a known CVD-associated GMM, in individuals living with alcohol use disorder. In a male murine binge-on-chronic alcohol model, we confirm gut microbial reorganization, elevation in PAGln levels, and the presence of cardiovascular pathophysiology. Fecal microbiota transplantation from pair-/alcohol-fed mice into naïve male mice demonstrates the transmissibility of PAGln production and the CVD phenotype. Independent of alcohol exposure, pharmacological-mediated increases in PAGln elicits direct cardiac and vascular dysfunction. PAGln induced hypercontractility and altered calcium cycling in isolated cardiomyocytes providing evidence of improper relaxation which corresponds to elevated filling pressures observed in vivo. Furthermore, PAGln directly induces vascular endothelial cell activation through induction of oxidative stress leading to endothelial cell dysfunction. We thus reveal that the alcohol-induced microbial reorganization and resultant GMM elevation, specifically PAGln, directly contributes to CVD.
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    The Apelin–Apelin Receptor Axis Triggers Cholangiocyte Proliferation and Liver Fibrosis During Mouse Models of Cholestasis
    (Wiley, 2021-06) Chen, Lixian; Zhou, Tianhao; White, Tori; O'Brien, April; Chakraborty, Sanjukta; Liangpunsakul, Suthat; Yang, Zhihong; Kennedy, Lindsey; Saxena, Romil; Wu, Chaodong; Meng, Fanyin; Huang, Qiaobing; Francis, Heather; Alpini, Gianfranco; Glaser, Shannon; Medicine, School of Medicine
    Background and Aims Apelin (APLN) is the endogenous ligand of its G protein–coupled receptor, apelin receptor (APJ). APLN serum levels are increased in human liver diseases. We evaluated whether the APLN–APJ axis regulates ductular reaction and liver fibrosis during cholestasis. Approach and Results We measured the expression of APLN and APJ and serum APLN levels in human primary sclerosing cholangitis (PSC) samples. Following bile duct ligation (BDL) or sham surgery, male wild-type (WT) mice were treated with ML221 (APJ antagonist) or saline for 1 week. WT and APLN−/− mice underwent BDL or sham surgery for 1 week. Multidrug resistance gene 2 knockout (Mdr2−/−) mice were treated with ML221 for 1 week. APLN levels were measured in serum and cholangiocyte supernatants, and cholangiocyte proliferation/senescence and liver inflammation, fibrosis, and angiogenesis were measured in liver tissues. The regulatory mechanisms of APLN–APJ in (1) biliary damage and liver fibrosis were examined in human intrahepatic biliary epithelial cells (HIBEpiCs) treated with APLN and (2) hepatic stellate cell (HSC) activation in APLN-treated human HSC lines (HHSteCs). APLN serum levels and biliary expression of APLN and APJ increased in PSC samples. APLN levels were higher in serum and cholangiocyte supernatants from BDL and Mdr2−/− mice. ML221 treatment or APLN−/− reduced BDL-induced and Mdr2−/−-induced cholangiocyte proliferation/senescence, liver inflammation, fibrosis, and angiogenesis. In vitro, APLN induced HIBEpiC proliferation, increased nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) expression, reactive oxygen species (ROS) generation, and extracellular signal–regulated kinase (ERK) phosphorylation. Pretreatment of HIBEpiCs with ML221, diphenyleneiodonium chloride (Nox4 inhibitor), N-acetyl-cysteine (NAC, ROS inhibitor), or PD98059 (ERK inhibitor) reduced APLN-induced cholangiocyte proliferation. Activation of HHSteCs was induced by APLN but reduced by NAC. Conclusions The APLN–APJ axis induces cholangiocyte proliferation through Nox4/ROS/ERK-dependent signaling and HSC activation through intracellular ROS. Modulation of the APLN–APJ axis may be important for managing cholangiopathies.
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    Cell-to-cell and organ-to-organ crosstalk in the pathogenesis of alcohol-associated liver disease
    (BMJ, 2024) Gao, Hui; Jiang, Yanchao; Zeng, Ge; Huda, Nazmul; Thoudam, Themis; Yang, Zhihong; Liangpunsakul, Suthat; Ma, Jing; Medicine, School of Medicine
    Alcohol-associated liver disease (ALD) is a growing global health concern and its prevalence and severity are increasing steadily. While bacterial endotoxin translocation into the portal circulation is a well-established key factor, recent evidence highlights the critical role of sterile inflammation, triggered by diverse stimuli, in alcohol-induced liver injury. This review provides a comprehensive analysis of the complex interactions within the hepatic microenvironment in ALD. It examines the contributions of both parenchymal cells, like hepatocytes, and non-parenchymal cells, such as hepatic stellate cells, Kupffer cells, neutrophils, and liver sinusoidal endothelial cells, in driving the progression of the disease. Additionally, we explored the involvement of key mediators, including cytokines, chemokines and inflammasomes, which regulate inflammatory responses and promote liver injury and fibrosis. A particular focus has been placed on extracellular vesicles (EVs) as essential mediators of intercellular communication both within and beyond the liver. These vesicles facilitate the transfer of signalling molecules, such as microRNAs and proteins, which modulate immune responses, fibrogenesis and lipid metabolism, thereby influencing disease progression. Moreover, we underscore the importance of organ-to-organ crosstalk, particularly in the gut-liver axis, where dysbiosis and increased intestinal permeability lead to microbial translocation, exacerbating hepatic inflammation. The adipose-liver axis is also highlighted, particularly the impact of adipokines and free fatty acids from adipose tissue on hepatic steatosis and inflammation in the context of alcohol consumption.
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    Critical Role of microRNA-21 in the Pathogenesis of Liver Diseases
    (Frontiers Media, 2020-01-31) Zhang, Ting; Yang, Zhihong; Kusumanchi, Praveen; Han, Sen; Liangpunsakul, Suthat; Medicine, School of Medicine
    MicroRNAs are small non-coding RNAs that range in length from 18 to 24 nucleotides. As one of the most extensively studied microRNAs, microRNA-21 (miR-21) is highly expressed in many mammalian cell types. It regulates multiple biological functions such as proliferation, differentiation, migration, and apoptosis. In this review, we summarized the mechanism of miR-21 in the pathogenesis of various liver diseases. While it is clear that miR-21 plays an important role in different types of liver diseases, its use as a diagnostic marker for specific liver disease or its therapeutic implication are not ready for prime time due to significant variability and heterogeneity in the expression of miR-21 in different types of liver diseases depending on the studies. Additional studies to further define miR-21 functions and its mechanism in association with each type of chronic liver diseases are needed before we can translate the bedside observations into clinical settings.
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    Distinct histopathological phenotypes of severe alcoholic hepatitis suggest different mechanisms driving liver injury and failure
    (American Society for Clinical Investigation, 2022) Ma, Jing; Guillot, Adrien; Yang, Zhihong; Mackowiak, Bryan; Hwang, Seonghwan; Park, Ogyi; Peiffer, Brandon J.; Ahmadi, Ali Reza; Melo, Luma; Kusumanchi, Praveen; Huda, Nazmul; Saxena, Romil; He, Yong; Guan, Yukun; Feng, Dechun; Sancho-Bru, Pau; Zang, Mengwei; MacGregor Cameron, Andrew; Bataller, Ramon; Tacke, Frank; Sun, Zhaoli; Liangpunsakul, Suthat; Gao, Bin; Pathology and Laboratory Medicine, School of Medicine
    Intrahepatic neutrophil infiltration has been implicated in severe alcoholic hepatitis (SAH) pathogenesis; however, the mechanism underlying neutrophil-induced injury in SAH remains obscure. This translational study aims to describe the patterns of intrahepatic neutrophil infiltration and its involvement in SAH pathogenesis. Immunohistochemistry analyses of explanted livers identified two SAH phenotypes despite a similar clinical presentation, one with high intrahepatic neutrophils (Neuhi), but low levels of CD8+ T cells, and vice versa. RNA-Seq analyses demonstrated that neutrophil cytosolic factor 1 (NCF1), a key factor in controlling neutrophilic ROS production, was upregulated and correlated with hepatic inflammation and disease progression. To study specifically the mechanisms related to Neuhi in AH patients and liver injury, we used the mouse model of chronic-plus-binge ethanol feeding and found that myeloid-specific deletion of the Ncf1 gene abolished ethanol-induced hepatic inflammation and steatosis. RNA-Seq analysis and the data from experimental models revealed that neutrophilic NCF1-dependent ROS promoted alcoholic hepatitis (AH) by inhibiting AMP-activated protein kinase (a key regulator of lipid metabolism) and microRNA-223 (a key antiinflammatory and antifibrotic microRNA). In conclusion, two distinct histopathological phenotypes based on liver immune phenotyping are observed in SAH patients, suggesting a separate mechanism driving liver injury and/or failure in these patients.
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    Downregulation of hepatic stem cell factor by Vivo-Morpholino treatment inhibits mast cell migration and decreases biliary damage/senescence and liver fibrosis in Mdr2−/− mice
    (Elsevier, 2019-12-01) Meadows, Vik; Kennedy, Lindsey; Hargrove, Laura; Demieville, Jennifer; Meng, Fanyin; Virani, Shohaib; Reinhart, Evan; Kyritsi, Konstantina; Invernizzi, Pietro; Yang, Zhihong; Wu, Nan; Liangpunsakul, Suthat; Alpini, Gianfranco; Francis, Heather; Medicine, School of Medicine
    Primary sclerosing cholangitis (PSC) is characterized by increased mast cell (MC) infiltration, biliary damage and hepatic fibrosis. Cholangiocytes secrete stem cell factor (SCF), which is a chemoattractant for c-kit expressed on MCs. We aimed to determine if blocking SCF inhibits MC migration, biliary damage and hepatic fibrosis. Methods: FVB/NJ and Mdr2-/- mice were treated with Mismatch or SCF Vivo-Morpholinos. We measured (i) SCF expression and secretion; (ii) hepatic damage; (iii) MC migration/activation and histamine signaling; (iv) ductular reaction and biliary senescence; and (v) hepatic fibrosis. In human PSC patients, SCF expression and secretion were measured. In vitro, cholangiocytes were evaluated for SCF expression and secretion. Biliary proliferation/senescence was measured in cholangiocytes pretreated with 0.1% BSA or the SCF inhibitor, ISK03. Cultured HSCs were stimulated with cholangiocyte supernatant and activation measured. MC migration was determined with cholangiocytes pretreated with BSA or ISK03 loaded into the bottom of Boyden chambers and MCs into top chamber. Results: Biliary SCF expression and SCF serum levels increase in human PSC. Cholangiocytes, but not hepatocytes, from SCF Mismatch Mdr2-/- mice have increased SCF expression and secretion. Inhibition of SCF in Mdr2-/- mice reduced (i) hepatic damage; (ii) MC migration; (iii) histamine and SCF serum levels; and (iv) ductular reaction/biliary senescence/hepatic fibrosis. In vitro, cholangiocytes express and secrete SCF. Blocking biliary SCF decreased MC migration, biliary proliferation/senescence, and HSC activation. Conclusion: Cholangiocytes secrete increased levels of SCF inducing MC migration, contributing to biliary damage/hepatic fibrosis. Targeting MC infiltration may be an option to ameliorate PSC progression.
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    Downregulation of hepatic stem cell factor by Vivo-Morpholino treatment inhibits mast cell migration and decreases biliary damage/senescence and liver fibrosis in Mdr2−/− mice
    (Elsevier, 2019) Meadows, Vik; Kennedy, Lindsey; Hargrove, Laura; Demieville, Jennifer; Meng, Fanyin; Virani, Shohaib; Reinhart, Evan; Kyritsi, Konstantina; Invernizzi, Pietro; Yang, Zhihong; Wu, Nan; Liangpunsakul, Suthat; Alpini, Gianfranco; Francis, Heather; Medicine, School of Medicine
    Introduction Primary sclerosing cholangitis (PSC) is characterized by increased mast cell (MC) infiltration, biliary damage and hepatic fibrosis. Cholangiocytes secrete stem cell factor (SCF), which is a chemoattractant for c-kit expressed on MCs. We aimed to determine if blocking SCF inhibits MC migration, biliary damage and hepatic fibrosis. Methods FVB/NJ and Mdr2−/− mice were treated with Mismatch or SCF Vivo-Morpholinos. We measured (i) SCF expression and secretion; (ii) hepatic damage; (iii) MC migration/activation and histamine signaling; (iv) ductular reaction and biliary senescence; and (v) hepatic fibrosis. In human PSC patients, SCF expression and secretion were measured. In vitro, cholangiocytes were evaluated for SCF expression and secretion. Biliary proliferation/senescence was measured in cholangiocytes pretreated with 0.1% BSA or the SCF inhibitor, ISK03. Cultured HSCs were stimulated with cholangiocyte supernatant and activation measured. MC migration was determined with cholangiocytes pretreated with BSA or ISK03 loaded into the bottom of Boyden chambers and MCs into top chamber. Results Biliary SCF expression and SCF serum levels increase in human PSC. Cholangiocytes, but not hepatocytes, from SCF Mismatch Mdr2−/− mice have increased SCF expression and secretion. Inhibition of SCF in Mdr2−/− mice reduced (i) hepatic damage; (ii) MC migration; (iii) histamine and SCF serum levels; and (iv) ductular reaction/biliary senescence/hepatic fibrosis. In vitro, cholangiocytes express and secrete SCF. Blocking biliary SCF decreased MC migration, biliary proliferation/senescence, and HSC activation. Conclusion Cholangiocytes secrete increased levels of SCF inducing MC migration, contributing to biliary damage/hepatic fibrosis. Targeting MC infiltration may be an option to ameliorate PSC progression.
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    Downregulation of p16 Decreases Biliary Damage and Liver Fibrosis in the Mdr2 / Mouse Model of Primary Sclerosing Cholangitis
    (Cognizant Communication Corporation, 2020-11) Kyritsi, Konstantina; Francis, Heather; Zhou, Tianhao; Ceci, Ludovica; Wu, Nan; Yang, Zhihong; Meng, Fanyin; Chen, Lixian; Baiocchi, Leonardo; Kundu, Debjyoti; Kennedy, Lindsey; Liangpunsakul, Suthat; Wu, Chaodong; Glaser, Shannon; Alpini, Gianfranco; Medicine, School of Medicine
    Biliary senescence and hepatic fibrosis are hallmarks of cholangiopathies including primary sclerosing cholangitis (PSC). Senescent cholangiocytes display senescence-associated secretory phenotypes [SASPs, e.g., transforming growth factor-1 (TGF-1)] that further increase biliary senescence (by an autocrine loop) and trigger liver fibrosis by paracrine mechanisms. The aim of this study was to determine the effect of p16 inhibition and role of the TGF-1/microRNA (miR)-34a/sirtuin 1 (SIRT1) axis in biliary damage and liver fibrosis in the Mdr2/ mouse model of PSC. We treated (i) in vivo male wild-type (WT) and Mdr2/ mice with p16 Vivo-Morpholino or controls before measuring biliary mass [intrahepatic bile duct mass (IBDM)] and senescence, biliary SASP levels, and liver fibrosis, and (ii) in vitro intrahepatic murine cholangiocyte lines (IMCLs) with small interfering RNA against p16 before measuring the mRNA expression of proliferation, senescence, and fibrosis markers. p16 and miR-34a increased but SIRT1 decreased in Mdr2/ mice and PSC human liver samples compared to controls. p16 immunoreactivity and biliary senescence and SASP levels increased in Mdr2/ mice but decreased in Mdr2/ mice treated with p16 Vivo-Morpholino. The increase in IBDM and hepatic fibrosis (observed in Mdr2/ mice) returned to normal values in Mdr2/ mice treated with p16 Vivo-Morpholino. TGF-1 immunoreactivity and biliary SASPs levels were higher in Mdr2/ compared to those of WT mice but returned to normal values in Mdr2/ mice treated with p16 Vivo-Morpholino. The expression of fibrosis/senescence markers decreased in cholangiocytes from Mdr2/ mice treated with p16 Vivo-Morpholino (compared to Mdr2/ mice) and in IMCLs (after p16 silencing) compared to controls. Modulation of the TGF-1/miR-34a/SIRT1 axis may be important in the management of PSC phenotypes.
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    Enhanced Ca2+-channeling complex formation at the ER-mitochondria interface underlies the pathogenesis of alcohol-associated liver disease
    (Springer Nature, 2023-03-27) Thoudam, Themis; Chanda, Dipanjan; Lee, Jung Yi; Jung, Min-Kyo; Sinam, Ibotombi Singh; Kim, Byung-Gyu; Park, Bo-Yoon; Kwon, Woong Hee; Kim, Hyo-Jeong; Kim, Myeongjin; Lim, Chae Won; Lee, Hoyul; Huh, Yang Hoon; Miller, Caroline A.; Saxena, Romil; Skill, Nicholas J.; Huda, Nazmul; Kusumanchi, Praveen; Ma, Jing; Yang, Zhihong; Kim, Min-Ji; Mun, Ji Young; Harris, Robert A.; Jeon, Jae-Han; Liangpunsakul, Suthat; Lee, In-Kyu; Pathology and Laboratory Medicine, School of Medicine
    Ca2+ overload-induced mitochondrial dysfunction is considered as a major contributing factor in the pathogenesis of alcohol-associated liver disease (ALD). However, the initiating factors that drive mitochondrial Ca2+ accumulation in ALD remain elusive. Here, we demonstrate that an aberrant increase in hepatic GRP75-mediated mitochondria-associated ER membrane (MAM) Ca2+-channeling (MCC) complex formation promotes mitochondrial dysfunction in vitro and in male mouse model of ALD. Unbiased transcriptomic analysis reveals PDK4 as a prominently inducible MAM kinase in ALD. Analysis of human ALD cohorts further corroborate these findings. Additional mass spectrometry analysis unveils GRP75 as a downstream phosphorylation target of PDK4. Conversely, non-phosphorylatable GRP75 mutation or genetic ablation of PDK4 prevents alcohol-induced MCC complex formation and subsequent mitochondrial Ca2+ accumulation and dysfunction. Finally, ectopic induction of MAM formation reverses the protective effect of PDK4 deficiency in alcohol-induced liver injury. Together, our study defines a mediatory role of PDK4 in promoting mitochondrial dysfunction in ALD.