Browsing by Author "Han, Sen"

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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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    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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    Long non-coding RNAs in liver diseases: Focusing on nonalcoholic fatty liver disease, alcohol-related liver disease, and cholestatic liver disease
    (The Korean Association for the Study of the Liver, 2020-10) Han, Sen; Zhang, Ting; Kusumanchi, Praveen; Huda, Nazmul; Jiang, Yanchao; Yang, Zhihong; Liangpunsakul, Suthat; Medicine, School of Medicine
    Long non-coding RNAs (lncRNAs), a class of transcribed RNA molecules with the lengths exceeding 200 nucleotides, are not translated into protein. They can modulate protein-coding genes by controlling transcriptional and posttranscriptional processes. The dysregulation of lncRNAs has been related to various pathological disorders. In this review, we summarized the current knowledge of lncRNAs and their implications in the pathogenesis of three common liver diseases: nonalcoholic fatty liver disease, alcohol-related liver disease, and cholestatic liver disease. Future studies to further define the role of lncRNAs and their mechanisms in various types of liver diseases should be explored. An improved understanding from these studies will provide us a useful perspective leading to mechanism-based intervention by targeting specific lncRNAs for the treatment of liver diseases.
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    Stress-responsive gene FKBP5 mediates alcohol-induced liver injury through the hippo pathway and CXCL1 signaling
    (Wiley, 2021-09) Kusumanchi, Praveen; Liang, Tiebing; Zhang, Ting; Ross, Ruth Ann; Han, Sen; Chandler, Kristina; Oshodi, Adepeju; Jiang, Yanchao; Dent, Alexander L.; Skill, Nicholas J.; Huda, Nazmul; Ma, Jing; Yang, Zhihong; Liangpunsakul, Suthat; Medicine, School of Medicine
    Chronic alcohol drinking is a major risk factor for alcohol-associated liver disease (ALD). FK506-binding protein 51 (FKBP5), a co-chaperone protein, is involved in many key regulatory pathways. It is known to be involved in stress-related disorders but there are no reports regarding its role in ALD. This present study aimed to examine the molecular mechanism of FKBP5 in ALD. We found a significant increase in hepatic FKBP5 transcripts and protein expression in patients with ALD and mice fed with chronic-plus-single binge ethanol. Loss of Fkbp5 in mice protected against alcohol-induced hepatic steatosis and inflammation. Transcriptomic analysis revealed a significant reduction of Tead1 and Cxcl1 mRNA in ethanol-fed Fkbp5-/- mice. Ethanol-induced Fkbp5 expression was secondary to downregulation of methylation level at its 5′ UTR promoter region. The increase in Fkbp5 expression led to induction in transcription factor Tead1 through Hippo signaling pathway. Fkbp5 can interact with YAP upstream kinase, MST1, affecting its ability to phosphorylate YAP and the inhibitory effect of hepatic YAP phosphorylation by ethanol leading to YAP nuclear translocation and TEAD1 activation. Activation of TEAD1 led to increased expression of its novel target, CXCL1, a chemokine-mediated neutrophil recruitment, causing hepatic inflammation and neutrophil infiltration in our mouse model. Conclusion We identified a novel FKBP5-YAP-TEAD1-CXCL1 axis in the pathogenesis of ALD. Loss of FKBP5 ameliorates alcohol-induced liver injury through the Hippo pathway and CXCL1 signaling, suggesting its potential role as a target for the treatment of ALD.