Browsing by Author "Zhou, Jiliang"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Clearance of damaged mitochondria via mitophagy is important to the protective effect of ischemic preconditioning in kidneys
    (Taylor & Francis, 2019-12) Livingston, Man J.; Wang, Jinghong; Zhou, Jiliang; Wu, Guangyu; Ganley, Ian G.; Hill, Joseph A.; Yin, Xiao-Ming; Dong, Zheng; Pathology and Laboratory Medicine, School of Medicine
    Ischemic preconditioning (IPC) affords tissue protection in organs including kidneys; however, the underlying mechanism remains unclear. Here we demonstrate an important role of macroautophagy/autophagy (especially mitophagy) in the protective effect of IPC in kidneys. IPC induced autophagy in renal tubular cells in mice and suppressed subsequent renal ischemia-reperfusion injury (IRI). The protective effect of IPC was abolished by pharmacological inhibitors of autophagy and by the ablation of Atg7 from kidney proximal tubules. Pretreatment with BECN1/Beclin1 peptide induced autophagy and protected against IRI. These results suggest the dependence of IPC protection on renal autophagy. During IPC, the mitophagy regulator PINK1 (PTEN induced putative kinase 1) was activated. Both IPC and BECN1 peptide enhanced mitolysosome formation during renal IRI in mitophagy reporter mice, suggesting that IPC may protect kidneys by activating mitophagy. We further established an in vitro model of IPC by inducing 'chemical ischemia' in kidney proximal tubular cells with carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Brief treatment with CCCP protected against subsequent injury in these cells and the protective effect was abrogated by autophagy inhibition. In vitro IPC increased mitophagosome formation, enhanced the delivery of mitophagosomes to lysosomes, and promoted the clearance of damaged mitochondria during subsequent CCCP treatment. IPC also suppressed mitochondrial depolarization, improved ATP production, and inhibited the generation of reactive oxygen species. Knockdown of Pink1 suppressed mitophagy and reduced the cytoprotective effect of IPC. Together, these results suggest that autophagy, especially mitophagy, plays an important role in the protective effect of IPC.Abbreviations: ACTB: actin, beta; ATG: autophagy related; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; BUN: blood urea nitrogen; CASP3: caspase 3; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; COX4I1: cytochrome c oxidase subunit 4I1; COX8: cytochrome c oxidase subunit 8; DAPI: 4',6-diamidino-2-phenylindole; DNM1L: dynamin 1 like; EGFP: enhanced green fluorescent protein; EM: electron microscopy; ER: endoplasmic reticulum; FC: floxed control; FIS1: fission, mitochondrial 1; FUNDC1: FUN14 domain containing 1; H-E: hematoxylin-eosin; HIF1A: hypoxia inducible factor 1 subunit alpha; HSPD1: heat shock protein family D (Hsp60) member 1; IMMT/MIC60: inner membrane mitochondrial protein; IPC: ischemic preconditioning; I-R: ischemia-reperfusion; IRI: ischemia-reperfusion injury; JC-1: 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide; KO: knockout; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; mito-QC: mito-quality control; mRFP: monomeric red fluorescent protein; NAC: N-acetylcysteine; PINK1: PTEN induced putative kinase 1; PPIB: peptidylprolyl isomerase B; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; RPTC: rat proximal tubular cells; SD: standard deviation; sIPC: simulated IPC; SQSTM1/p62: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling.
  • Thumbnail Image
    Item
    Long noncoding RNA NEAT1 (nuclear paraspeckle assembly transcript 1) is critical for phenotypic switching of vascular smooth muscle cells
    (National Academy of Sciences, 2018-09-11) Ahmed, Abu Shufian Ishtiaq; Dong, Kunzhe; Liu, Jinhua; Wen, Tong; Yu, Luyi; Xu, Fei; Kang, Xiuhua; Osman, Islam; Hu, Guoqing; Bunting, Kristopher M.; Crethers, Danielle; Gao, Hongyu; Zhang, Wei; Liu, Yunlong; Wen, Ke; Agarwal, Gautam; Hirose, Tetsuro; Nakagawa, Shinichi; Vazdarjanova, Almira; Zhou, Jiliang; Medicine, School of Medicine
    In response to vascular injury, vascular smooth muscle cells (VSMCs) may switch from a contractile to a proliferative phenotype thereby contributing to neointima formation. Previous studies showed that the long noncoding RNA (lncRNA) NEAT1 is critical for paraspeckle formation and tumorigenesis by promoting cell proliferation and migration. However, the role of NEAT1 in VSMC phenotypic modulation is unknown. Herein we showed that NEAT1 expression was induced in VSMCs during phenotypic switching in vivo and in vitro. Silencing NEAT1 in VSMCs resulted in enhanced expression of SM-specific genes while attenuating VSMC proliferation and migration. Conversely, overexpression of NEAT1 in VSMCs had opposite effects. These in vitro findings were further supported by in vivo studies in which NEAT1 knockout mice exhibited significantly decreased neointima formation following vascular injury, due to attenuated VSMC proliferation. Mechanistic studies demonstrated that NEAT1 sequesters the key chromatin modifier WDR5 (WD Repeat Domain 5) from SM-specific gene loci, thereby initiating an epigenetic "off" state, resulting in down-regulation of SM-specific gene expression. Taken together, we demonstrated an unexpected role of the lncRNA NEAT1 in regulating phenotypic switching by repressing SM-contractile gene expression through an epigenetic regulatory mechanism. Our data suggest that NEAT1 is a therapeutic target for treating occlusive vascular diseases.
  • Thumbnail Image
    Item
    Novel Myh11 Dual Reporter Mouse Model Provides Definitive Labeling and Identification of Smooth Muscle Cells—Brief Report
    (AHA, 2021-02) Ruan, Jian; Zhang, Lu; Hu, Donghua; Qu, Xianghu; Yang, Fan; Chen, Fuxue; He, Xiangqin; Shen, Jian; Dong, Kunzhe; Sweet, Megan; Sanchez, Christina; Li, Deqiang; Shou, Weinian; Zhou, Jiliang; Cai, Chen-Leng; Pediatrics, School of Medicine
    Objective: Myh11 encodes a myosin heavy chain protein that is specifically expressed in smooth muscle cells (SMCs) and is important for maintaining vascular wall stability. The goal of this study is to generate a Myh11 dual reporter mouse line for definitive visualization of MYH11+ SMCs in vivo. Approach and Results: We generated a Myh11 knock-in mouse model by inserting LoxP-nlacZ-4XpolyA-LoxP-H2B-GFP-polyA-FRT-Neo-FRT reporter cassette into the Myh11 gene locus. The nuclear (n) lacZ-4XpolyA cassette is flanked by 2 LoxP sites followed by H2B-GFP (histone 2B fused green fluorescent protein). Upon Cre-mediated recombination, nlacZ-stop cassette is removed thereby permitting nucleus localized H2B-GFP expression. Expression of the nuclear localized lacZ or H2B-GFP is under control of the endogenous Myh11 promoter. Nuclear lacZ was expressed specifically in SMCs at embryonic and adult stages. Following germline Cre-mediated deletion of nuclear lacZ, H2B-GFP was specifically expressed in the nuclei of SMCs. Comparison of nuclear lacZ expression with Wnt1Cre and Mef2cCre mediated-H2B-GFP expression revealed heterogenous origins of SMCs from neural crest and second heart field in the great arteries and coronary vessels adjacent to aortic root. Conclusions: The Myh11 knock-in dual reporter mouse model offers an exceptional genetic tool to visualize and trace the origins of SMCs in mice.