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Haiqin Xie - One of the best experts on this subject based on the ideXlab platform.
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LncRNA LOXL1-AS1 controls osteogenic and adipocytic differentiation of bone marrow mesenchymal stem cells in postmenopausal osteoporosis through regulating the miR-196a-5p/Hmga2 axis.
Journal of Bone and Mineral Metabolism, 2020Co-Authors: Ling Zhang, Haiqin XieAbstract:Introduction Exploring molecular mechanisms of human bone marrow mesenchymal stem cells (hBMMSCs) differentiation, a crucial step for bone formation, is a new direction for treating postmenopausal osteoporosis. LncRNAs are involved in lots of biological processes including hBMMSCs differentiation. The present study aimed to explore the effect of LOXL1-AS1 on hBMMSCs differentiation. Materials and methods We examined the expression levels of LOXL1-AS1, miR-196a-5p and Hmga2 in peripheral blood from postmenopausal osteoporosis patients by RT-qPCR, and detected their changes during the osteogenic differentiation of hBMMSCs by RT-qPCR. RT-qPCR and western blot measured the level of biomarkers of bone formation and osteogenic differentiation (osteopontin, OPN; Alkaline phosphatase, ALP; Runt-related transcription factor-2, Runx-2). The effects of LOXL1-AS1 on the osteogenic and adipocytic differentiation of hBMMSCs were, respectively, determined by ALP, ARS staining assays and oil red O staining assay. Results The abnormal high expression of LOXL1-AS1 was found in patients. LOXL1-AS1 expression showed a gradual decrease during the osteogenic differentiation of hBMMSCs. However, LOXL1-AS1 overexpression inhibited the hBMMSCs osteogenic differentiation but promoted adipocytic differentiation. Furthermore, LOXL1-AS1 was identified to be a sponge of miR-196a-5p and Hmga2 as a target gene of miR-196a-5p. Besides, LOXL1-AS1 sponged miR-196a-5p to mediate Hmga2 expression, which played contrary effects on regulating osteogenic and adipocytic differentiation of hBMMSCs. Moreover, LOXL1-AS1/miR-196a-5p/Hmga2 axis regulated hBMMSCs differentiation through controlling C/EBPβ-mediated PPARγ expression. Conclusion These findings facilitate understanding the molecular mechanism of hBMMSCs differentiation and bring up a novel sight for postmenopausal osteoporosis therapy.
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lncrna LOXL1 as1 controls osteogenic and adipocytic differentiation of bone marrow mesenchymal stem cells in postmenopausal osteoporosis through regulating the mir 196a 5p hmga2 axis
Journal of Bone and Mineral Metabolism, 2020Co-Authors: Ling Zhang, Haiqin XieAbstract:Exploring molecular mechanisms of human bone marrow mesenchymal stem cells (hBMMSCs) differentiation, a crucial step for bone formation, is a new direction for treating postmenopausal osteoporosis. LncRNAs are involved in lots of biological processes including hBMMSCs differentiation. The present study aimed to explore the effect of LOXL1-AS1 on hBMMSCs differentiation. We examined the expression levels of LOXL1-AS1, miR-196a-5p and Hmga2 in peripheral blood from postmenopausal osteoporosis patients by RT-qPCR, and detected their changes during the osteogenic differentiation of hBMMSCs by RT-qPCR. RT-qPCR and western blot measured the level of biomarkers of bone formation and osteogenic differentiation (osteopontin, OPN; Alkaline phosphatase, ALP; Runt-related transcription factor-2, Runx-2). The effects of LOXL1-AS1 on the osteogenic and adipocytic differentiation of hBMMSCs were, respectively, determined by ALP, ARS staining assays and oil red O staining assay. The abnormal high expression of LOXL1-AS1 was found in patients. LOXL1-AS1 expression showed a gradual decrease during the osteogenic differentiation of hBMMSCs. However, LOXL1-AS1 overexpression inhibited the hBMMSCs osteogenic differentiation but promoted adipocytic differentiation. Furthermore, LOXL1-AS1 was identified to be a sponge of miR-196a-5p and Hmga2 as a target gene of miR-196a-5p. Besides, LOXL1-AS1 sponged miR-196a-5p to mediate Hmga2 expression, which played contrary effects on regulating osteogenic and adipocytic differentiation of hBMMSCs. Moreover, LOXL1-AS1/miR-196a-5p/Hmga2 axis regulated hBMMSCs differentiation through controlling C/EBPβ-mediated PPARγ expression. These findings facilitate understanding the molecular mechanism of hBMMSCs differentiation and bring up a novel sight for postmenopausal osteoporosis therapy.
Hong You - One of the best experts on this subject based on the ideXlab platform.
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selective depletion of hepatic stellate cells specific LOXL1 alleviates liver fibrosis
The FASEB Journal, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Tao Huang, Mengyang Zhang, Hong YouAbstract:The role of LOXL1 in fibrosis via mediating ECM crosslinking and stabilization is well established; however, the role of hepatic stellate cells (HSCs)-specific LOXL1 in the development of fibrosis remains unknown. We generated HSCs-specific LOXL1-depleted mice (LOXL1Gfap-cre mice) to investigate the HSCs-specific contribution of LOXL1 in the pathogenesis of fibrosis. LOXL1fl/fl mice were used as the control. Furthermore, we used RNA sequencing to explore the underlying changes in the transcriptome. Results of the sirius red staining, type I collagen immunolabeling, and hydroxyproline content analysis, coupled with the reduced expression of profibrogenic genes revealed that LOXL1Gfap-cre mice with CCl4 -induced fibrosis exhibited decreased hepatic fibrosis. In addition, LOXL1Gfap-cre mice exhibited reduced macrophage tissue infiltration by CD68-positive cells and decreased expression of inflammatory genes compared with the controls. RNA sequencing identified integrin α8 (ITGA8) as a key modulator of LOXL1-mediated liver fibrosis. Functional analyses showed that siRNA silencing of Itga8 in cultured fibroblasts led to a decline in the LOXL1 expression and inhibition of fibroblast activation. Mechanistic analyses indicated that LOXL1 activated the FAK/PI3K/AKT/HIF1a signaling pathway, and the addition of inhibitors of FAK or PI3K reversed these results via downregulation of LOXL1. Furthermore, HIF1a directly interacted with LOXL1 and upregulated its expression, indicating that LOXL1 can positively self-regulate by forming a positive feedback loop with the FAK/PI3K/AKT/HIF1a pathway. We demonstrated that HSCs-specific LOXL1 deficiency prevented fibrosis, inflammation and that ITGA8/FAK/PI3K/AKT/HIF1a was essential for the function and expression of LOXL1. Knowledge of this approach can provide novel mechanisms and targets to treat fibrosis in the future.
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hepatic stellate cells specific LOXL1 deficiency abrogates hepatic inflammation fibrosis and corrects lipid metabolic abnormalities in non obese nash mice
Hepatology International, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Yiwen Shi, Tao Huang, Hong YouAbstract:Lysyl oxidase-like-1 (LOXL1), a vital cross-linking enzyme in extracellular matrix (ECM) maintenance, promotes fibrosis via enhancement of ECM stability. However, the potential role of LOXL1 in the pathogenesis of nonalcoholic steatohepatitis (NASH) has not been previously studied. We generated LOXL1fl/fl mice to selectively delete LOXL1 in hepatic stellate cells (HSCs) (LOXL1fl/flGfapcre; LOXL1fl/fl as littermate controls) and then examined liver pathology and metabolic profiles in LOXL1fl/flGfapcre fed with either a choline-deficient L-amino acid-defined (CDAA) diet or an isocaloric control diet for 16 weeks. Thereafter, the findings from the animal model were confirmed in 23 patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD). LOXL1 was significantly increased in CDAA induced non-obese NASH compared with the control diet, and LOXL1 deficient in HSCs ameliorated CDAA-induced inflammation and fibrosis, with reduced expression of pro-inflammation and pro-fibrogenic genes in the HSCs-specific LOXL1 knockout mice model. Interestingly, LOXL1 deficient in HSCs could attenuate hepatic steatosis and reverse the metabolic disorder by restoring adipose tissue function without altering the effect of hepatic lipogenesis gene expression in non-obese NASH model. More importantly, analyses of serum LOXL1 and leptin levels from NAFLD patients revealed that LOXL1 was positively correlated with histological fibrosis progression, whereas it was inversely correlated with leptin levels, especially in non-obese NAFLD patients. LOXL1 may contribute to fibrosis progression in non-obese NAFLD, and HSCs-specific knockout of LOXL1 attenuated liver steatosis, inflammation, fibrosis, , and improved lipid metabolic abnormalities. Hence, LOXL1 inhibition may serve as a new therapeutic strategy for NASH.
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hepatic stellate cells specific LOXL1 deficiency abrogates hepatic inflammation fibrosis and corrects lipid metabolic abnormalities in non obese nash mice
Social Science Research Network, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Yiwen Shi, Tao Huang, Hong YouAbstract:Background & Aims: Lysyl oxidase-like-1 (LOXL1), a vital crosslinking enzyme in extracellular matrix (ECM) protein maintenance, is well established in fibrosis via mediating ECM stabilization. However, the potential role of LOXL1 in the pathogenesis of nonalcoholic steatohepatitis (NASH) has not been previously studied. Methods: We generated LOXL1 fl/fl mice to selectively delete LOXL1 in hepatic stellate cells (HSCs) (LOXL1fl/flGfapcre; LOXL1fl/fl as littermate controls) and then examined liver pathology and metabolic context in LOXL1fl/flGfapcre fed a choline-deficient L-amino acid-defined (CDAA) diet or an isocaloric control diet for 16 weeks. We confirmed study findings in 23 patients with biopsy-proven NAFLD. Results: LOXL1 was significantly increased in CDAA induced non-obese NASH compared with control diet. Here, utilizing a HSCs-specific deletion of LOXL1 model, we found that LOXL1 deficient in HSCs ameliorated CDAA-induced inflammation and fibrosis, with reduced expression of pro-inflammation and pro-fibrogenic genes. Interestingly, CDAA-fed LOXL1 deficient mice was associated with improved body weight and attenuated hepatic steatosis and to an up-regulation of leptin in adipose tissue and in serum, without changes in hepatic lipogenesis gene expression, compared with CDAA-fed control mice. Most importantly, analyses of serum LOXL1 and leptin levels from NAFLD patients revealed that LOXL1 was positively correlated with histological fibrosis progression, whereas was inversely correlated with leptin levels, especially in non-obese NAFLD patients. Conclusion: In a mouse model of CDAA-induced non-obese NASH, selective deletion of LOXL1 from HSCs attenuated steatohepatitis, hepatic fibrosis and improved lipid metabolic abnormalities. Hence, LOXL1 inhibition may serve as a new therapeutic strategy for NASH. Funding Statement: This study was supported by the National Natural Science Foundation of China (81670539 and 81500456). Declaration of Interests: The authors disclose no conflicts. Ethics Approval Statement: (Human) The Ethics Committee of Beijing Friendship Hospital approved study (No.: 2018-P2-228-02). (Animal) This study was approved by the Institutional Animal Care and Usage Committee of the Beijing Friendship Hospital, Capital Medical University, Beijing, China.
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Inhibition of lysyl oxidase-like 1 (LOXL1) expression arrests liver fibrosis progression in cirrhosis by reducing elastin crosslinking.
Biochimica et biophysica acta. Molecular basis of disease, 2018Co-Authors: Wenshan Zhao, Aiting Yang, Wei Chen, Ping Wang, Tianhui Liu, Min Cong, Xuzhen Yan, Jidong Jia, Hong YouAbstract:Mature crosslinked-poly-elastin deposition has been found to be associated with liver fibrosis. However, the regulation of crosslinked/insoluble elastin in liver fibrosis remains largely unknown. Here, we investigated the contribution of lysyl oxidases (LOXs) family, mediated elastin crosslinking, to liver fibrogenesis. We established carbon tetrachloride (CCl4)-induced liver fibrotic and cirrhotic models and found that crosslinked/insoluble elastin levels spiked only in cirrhosis stage during disease progression, in comparison to collagen Ι levels which increased continuously though all stages. Among the LOXs family members, only LOX-like 1 (LOXL1) levels were coincident with the appearance of crosslinked/insoluble elastin. These coincidences included that LOXL1 expression increased (34 fold) in cirrhosis, localized with α-smooth muscle actin (SMA) and was absent in normal and fibrotic livers. In LX-2 cells, LOXL1 silencing arrested expression of α-SMA, elastin and collagen Ι. Our previously characterized adeno-associated vector (AAV) 2/8 shRNA was shown to effectively downregulate LOXL1 expression in CCl4 induced fibrosis mice models. These resulted in delicate and thinner septa and less crosslinked elastin, with a 58% loss of elastin area and 51% decrease of collagen area. Our findings strongly suggested that elastin crosslinking and LOXL1 were co-associated with liver cirrhosis, while selective inhibition of LOXL1 arrested disease progression by reducing crosslinking of elastin.
Matthias Zenkel - One of the best experts on this subject based on the ideXlab platform.
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The role of lysyl oxidase-like 1 (LOXL1) in exfoliation syndrome and glaucoma.
Experimental Eye Research, 2019Co-Authors: Ursula Schlötzer-schrehardt, Matthias ZenkelAbstract:Abstract Exfoliation syndrome (XFS) is an age-related systemic disease that affects the extracellular matrix. It increases the risk of glaucoma (exfoliation glaucoma, XFG) and susceptibility to diseases of elastin-rich connective tissues. LOXL1 (lysyl oxidase-like 1) is still recognized as the major genetic effect locus in XFS and XFG in all populations worldwide, although its genetic architecture is incompletely understood. LOXL1 is a key cross-linking enzyme in elastic fiber formation and remodeling, which is compatible with the pathogenetic concept of XFS as a specific type of elastosis. This review provides an overview on the current knowledge about the role of LOXL1 in the etiology and pathophysiology of XFS and XFG. It covers the known genetic associations at the LOXL1 locus, potential mechanisms of gene regulation, implications of LOXL1 in XFS-associated fibrosis and connective tissue homeostasis, its role in the development of glaucoma and associated systemic diseases, and the currently available LOXL1-based in vivo and in vitro models. Finally, it also identifies gaps in knowledge and suggests potential areas for future research.
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Posttranscriptional Regulation of LOXL1 Expression Via Alternative Splicing and Nonsense-Mediated mRNA Decay as an Adaptive Stress Response.
Investigative Opthalmology & Visual Science, 2017Co-Authors: Daniel Berner, Francesca Pasutto, Friedrich E. Kruse, Matthias Zenkel, Panah Liravi, Ursula Hoja, G. C. Gusek-schneider, Johannes Schödel, André Reis, Ursula Schlötzer-schrehardtAbstract:Purpose Alternative mRNA splicing coupled to nonsense-mediated decay (NMD) is a common mRNA surveillance pathway also known to dynamically modulate gene expression in response to cellular stress. Here, we investigated the involvement of this pathway in the regulation of lysyl oxidase-like 1 (LOXL1) expression in response to pseudoexfoliation (PEX)-associated pathophysiologic factors. Methods Transcript levels of LOXL1 isoforms were determined in ocular tissues obtained from donor eyes without and with PEX syndrome. Pseudoexfoliation-relevant cell types, including human Tenon's capsule fibroblasts (hTCF) and trabecular meshwork cells (hTMC), were exposed to puromycin, caffeine, TGF-β1, homocysteine, IL-6, retinoic acid, UV-B radiation, oxidative stress, and mechanical stress for up to 48 hours. Western blot analysis was carried out using antibodies against LOXL1, (phosphorylated-) eukaryotic initiation factor 2-α (eIF2-α), and regulator of nonsense transcripts 2 (UPF2). RNA interference was used to knockdown UPF1-3 and Serine/threonine-protein kinase (SMG1). Results Constitutive expression of wild-type LOXL1 and alternatively spliced LOXL1-a transcripts was detected in all ocular tissues showing highest levels in trabecular meshwork and differential expression between PEX and control specimens. LOXL1-a transcripts were upregulated in hTCF and hTMC by NMD inhibitors puromycin and caffeine (≥6-fold; P < 0.01) or after knockdown of NMD core factors (≥2-fold; P < 0.05), whereas mRNA and protein levels of LOXL1 were reduced (≤0.8 fold; P < 0.05). Exposure of cells to various PEX-associated (stress) factors, including TGF-β1, UV-B light, oxidative stress, mechanical stress, and retinoic acid enhanced LOXL1-a transcript levels (≥1.5-fold; P < 0.05), while partially downregulating LOXL1 levels (≤0.7-fold; P < 0.05). Stress-induced inhibition of NMD was dependent on phosphorylation of eIF2α. Conclusions These findings provide evidence for a functional role of alternative splicing coupled to NMD in the posttranscriptional regulation of LOXL1 gene expression and suggest this mechanism to represent a dynamic mode of adapting LOXL1 expression to PEX-associated environmental and nutritional cues.
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Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1.
Nature Communications, 2017Co-Authors: Francesca Pasutto, Matthias Zenkel, Panah Liravi, Daniel Berner, Ursula Hoja, Johannes Schödel, Steffen Uebe, Fulvia Ferrazzi, Mineo Ozaki, Daniela PaoliAbstract:Although lysyl oxidase-like 1 (LOXL1) is known as the principal genetic risk factor for pseudoexfoliation (PEX) syndrome, a major cause of glaucoma and cardiovascular complications, no functional variants have been identified to date. Here, we conduct a genome-wide association scan on 771 German PEX patients and 1,350 controls, followed by independent testing of associated variants in Italian and Japanese data sets. We focus on a 3.5-kb four-component polymorphic locus positioned spanning introns 1 and 2 of LOXL1 with enhancer-like chromatin features. We find that the rs11638944:C>G transversion exerts a cis-acting effect on the expression levels of LOXL1, mediated by differential binding of the transcription factor RXRα (retinoid X receptor alpha) and by modulating alternative splicing of LOXL1, eventually leading to reduced levels of LOXL1 mRNA in cells and tissues of risk allele carriers. These findings uncover a functional mechanism by which common noncoding variants influence LOXL1 expression.
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The pathophysiology of pseudoexfoliation syndrome is affected by interaction of TGF-β1 and LOXL1
Acta Ophthalmologica, 2015Co-Authors: Panah Liravi, Matthias Zenkel, Friedrich E. Kruse, Ursula Schlötzer-schrehardtAbstract:Purpose The cross-linking enzyme lysyl oxidase-like 1 (LOXL1) and profibrotic transforming growth factor (TGF)-s1 play key roles in pathophysiology of pseudoexfoliation (PEX) syndrome/glaucoma. The purpose of this study was to investigate the interaction between LOXL1 and TGF-s1 with respect to the PEX-specific disordered matrix metabolism. Methods Primary human Tenon's capsule fibroblasts (hTCF) obtained from patients were treated with TGF-s1 (0-10 ng/ml) for 12-72 hours without or with preincubation with inhibitors of TGF-β signalling pathways. Expression of LOXL1 and PEX-specific extracellular matrix components was examined by using quantitative RT-PCR and Western immunoblot analysis. Direct binding of LOXL1 to TGF-s1 was analyzed by blot overlay assay and solid phase ELISA using purified LOXL1, recombinant human TGF-s1, TGFs1-LAP. The effect of LOXL1 on TGF-s1 signaling was analyzed using TGF-s receptor signaling real time PCR assays (BioRad) after transient transfection of hTCF with a full-length pCMV6-LOXL1 vector construct/with empty vector . Results TGFs1 significantly increased LOXL1 expression, secretion and enzymatic activity and correlated with enhanced expression of BMP-1, elastin, fibrillin-1, fibulin-4 and fibulin-5 with peak effects at 10 ng/ml for 48 hours. This induction was blocked by TGF-β receptor inhibitors and inhibitors of the canonical Smad and non-canonical signaling pathways. Direct binding between LOXL1 and TGFs1-LAP was demonstrated by Blot overlay assays and ELISA. LOXL1 overexpression temporarily upregulates different transcriptional regulators and some protein kinases of p38-MAPK signalling pathway after 12 to 24 hours post-transfection. Conclusions The results of this study indicate that the interaction of LOXL1 and TGF-s1 plays an important role in the PEX-associated abnormal matrix metabolism and fibrosis.
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Expression and regulation of LOXL1 and elastin-related genes in eyes with exfoliation syndrome.
Journal of Glaucoma, 2014Co-Authors: Matthias Zenkel, Ursula Schlötzer-schrehardtAbstract:Exfoliation syndrome (XFS) is a complex, late-onset disorder of the elastic fiber system and the most common identifiable cause of open-angle glaucoma. Strong genetic risk is conferred by the lysyl oxidase-like 1 (LOXL1) gene, but additional comodulating factors are necessary for the manifestation of the disease. The aim of this study was to establish a comprehensive expression profile of LOXL1 and elastic proteins in XFS eyes and to analyze their regulation in an in vitro cell culture system. Eyes with XFS with and without glaucoma, and normal control eyes were analyzed for major elastic fiber components (elastin, fibrillin-1, fibulin-4), and lysyl oxidase (LOX) enzymes by real-time PCR, immunohistochemistry, and electron microscopy. Cultured human Tenon's capsule fibroblasts were exposed to transforming growth factor-β1, IL-6, homocysteine, oxidative stress, hypoxia, or ultraviolet radiation, and changes in the expression of LOXL1 and elastic components of XFS material were assessed by real-time PCR, immunohistochemistry, and Western blotting. LOXL1 expression in anterior eye tissues was significantly increased in early XFS stages but was decreased in advanced stages as compared with controls. LOXL1 was also found to be a major component of XFS material and to colocalize with elastin, fibrillin-1, and fibulin-4, which were upregulated in parallel to LOXL1. In contrast, in most posterior segment tissues, LOXL1 and elastic fiber proteins displayed no differential expression. Interestingly, lamina cribrosa specimens of early and late XFS stages without and with glaucoma revealed a selective downregulation of LOXL1 and elastic fiber components on the mRNA and protein level, which was associated with pronounced ultrastructural alterations of the laminar elastic fiber network in XFS eyes. Treatment of cultured cells with XFS-associated pathogenetic stimuli induced a significant increase in the expression of LOXL1 and elastic proteins and resulted in their assembly into XFS-like fibrils in vitro. The findings support the notion that both genetic and nongenetic factors may cooperate in the stable accumulation of XFS aggregates and provide evidence for a XFS-specific elastinopathy of the lamina cribrosa, possibly rendering XFS eyes more vulnerable to pressure-induced optic nerve damage and glaucoma development.
Ling Zhang - One of the best experts on this subject based on the ideXlab platform.
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LncRNA LOXL1-AS1 controls osteogenic and adipocytic differentiation of bone marrow mesenchymal stem cells in postmenopausal osteoporosis through regulating the miR-196a-5p/Hmga2 axis.
Journal of Bone and Mineral Metabolism, 2020Co-Authors: Ling Zhang, Haiqin XieAbstract:Introduction Exploring molecular mechanisms of human bone marrow mesenchymal stem cells (hBMMSCs) differentiation, a crucial step for bone formation, is a new direction for treating postmenopausal osteoporosis. LncRNAs are involved in lots of biological processes including hBMMSCs differentiation. The present study aimed to explore the effect of LOXL1-AS1 on hBMMSCs differentiation. Materials and methods We examined the expression levels of LOXL1-AS1, miR-196a-5p and Hmga2 in peripheral blood from postmenopausal osteoporosis patients by RT-qPCR, and detected their changes during the osteogenic differentiation of hBMMSCs by RT-qPCR. RT-qPCR and western blot measured the level of biomarkers of bone formation and osteogenic differentiation (osteopontin, OPN; Alkaline phosphatase, ALP; Runt-related transcription factor-2, Runx-2). The effects of LOXL1-AS1 on the osteogenic and adipocytic differentiation of hBMMSCs were, respectively, determined by ALP, ARS staining assays and oil red O staining assay. Results The abnormal high expression of LOXL1-AS1 was found in patients. LOXL1-AS1 expression showed a gradual decrease during the osteogenic differentiation of hBMMSCs. However, LOXL1-AS1 overexpression inhibited the hBMMSCs osteogenic differentiation but promoted adipocytic differentiation. Furthermore, LOXL1-AS1 was identified to be a sponge of miR-196a-5p and Hmga2 as a target gene of miR-196a-5p. Besides, LOXL1-AS1 sponged miR-196a-5p to mediate Hmga2 expression, which played contrary effects on regulating osteogenic and adipocytic differentiation of hBMMSCs. Moreover, LOXL1-AS1/miR-196a-5p/Hmga2 axis regulated hBMMSCs differentiation through controlling C/EBPβ-mediated PPARγ expression. Conclusion These findings facilitate understanding the molecular mechanism of hBMMSCs differentiation and bring up a novel sight for postmenopausal osteoporosis therapy.
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lncrna LOXL1 as1 controls osteogenic and adipocytic differentiation of bone marrow mesenchymal stem cells in postmenopausal osteoporosis through regulating the mir 196a 5p hmga2 axis
Journal of Bone and Mineral Metabolism, 2020Co-Authors: Ling Zhang, Haiqin XieAbstract:Exploring molecular mechanisms of human bone marrow mesenchymal stem cells (hBMMSCs) differentiation, a crucial step for bone formation, is a new direction for treating postmenopausal osteoporosis. LncRNAs are involved in lots of biological processes including hBMMSCs differentiation. The present study aimed to explore the effect of LOXL1-AS1 on hBMMSCs differentiation. We examined the expression levels of LOXL1-AS1, miR-196a-5p and Hmga2 in peripheral blood from postmenopausal osteoporosis patients by RT-qPCR, and detected their changes during the osteogenic differentiation of hBMMSCs by RT-qPCR. RT-qPCR and western blot measured the level of biomarkers of bone formation and osteogenic differentiation (osteopontin, OPN; Alkaline phosphatase, ALP; Runt-related transcription factor-2, Runx-2). The effects of LOXL1-AS1 on the osteogenic and adipocytic differentiation of hBMMSCs were, respectively, determined by ALP, ARS staining assays and oil red O staining assay. The abnormal high expression of LOXL1-AS1 was found in patients. LOXL1-AS1 expression showed a gradual decrease during the osteogenic differentiation of hBMMSCs. However, LOXL1-AS1 overexpression inhibited the hBMMSCs osteogenic differentiation but promoted adipocytic differentiation. Furthermore, LOXL1-AS1 was identified to be a sponge of miR-196a-5p and Hmga2 as a target gene of miR-196a-5p. Besides, LOXL1-AS1 sponged miR-196a-5p to mediate Hmga2 expression, which played contrary effects on regulating osteogenic and adipocytic differentiation of hBMMSCs. Moreover, LOXL1-AS1/miR-196a-5p/Hmga2 axis regulated hBMMSCs differentiation through controlling C/EBPβ-mediated PPARγ expression. These findings facilitate understanding the molecular mechanism of hBMMSCs differentiation and bring up a novel sight for postmenopausal osteoporosis therapy.
Aiting Yang - One of the best experts on this subject based on the ideXlab platform.
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selective depletion of hepatic stellate cells specific LOXL1 alleviates liver fibrosis
The FASEB Journal, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Tao Huang, Mengyang Zhang, Hong YouAbstract:The role of LOXL1 in fibrosis via mediating ECM crosslinking and stabilization is well established; however, the role of hepatic stellate cells (HSCs)-specific LOXL1 in the development of fibrosis remains unknown. We generated HSCs-specific LOXL1-depleted mice (LOXL1Gfap-cre mice) to investigate the HSCs-specific contribution of LOXL1 in the pathogenesis of fibrosis. LOXL1fl/fl mice were used as the control. Furthermore, we used RNA sequencing to explore the underlying changes in the transcriptome. Results of the sirius red staining, type I collagen immunolabeling, and hydroxyproline content analysis, coupled with the reduced expression of profibrogenic genes revealed that LOXL1Gfap-cre mice with CCl4 -induced fibrosis exhibited decreased hepatic fibrosis. In addition, LOXL1Gfap-cre mice exhibited reduced macrophage tissue infiltration by CD68-positive cells and decreased expression of inflammatory genes compared with the controls. RNA sequencing identified integrin α8 (ITGA8) as a key modulator of LOXL1-mediated liver fibrosis. Functional analyses showed that siRNA silencing of Itga8 in cultured fibroblasts led to a decline in the LOXL1 expression and inhibition of fibroblast activation. Mechanistic analyses indicated that LOXL1 activated the FAK/PI3K/AKT/HIF1a signaling pathway, and the addition of inhibitors of FAK or PI3K reversed these results via downregulation of LOXL1. Furthermore, HIF1a directly interacted with LOXL1 and upregulated its expression, indicating that LOXL1 can positively self-regulate by forming a positive feedback loop with the FAK/PI3K/AKT/HIF1a pathway. We demonstrated that HSCs-specific LOXL1 deficiency prevented fibrosis, inflammation and that ITGA8/FAK/PI3K/AKT/HIF1a was essential for the function and expression of LOXL1. Knowledge of this approach can provide novel mechanisms and targets to treat fibrosis in the future.
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hepatic stellate cells specific LOXL1 deficiency abrogates hepatic inflammation fibrosis and corrects lipid metabolic abnormalities in non obese nash mice
Hepatology International, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Yiwen Shi, Tao Huang, Hong YouAbstract:Lysyl oxidase-like-1 (LOXL1), a vital cross-linking enzyme in extracellular matrix (ECM) maintenance, promotes fibrosis via enhancement of ECM stability. However, the potential role of LOXL1 in the pathogenesis of nonalcoholic steatohepatitis (NASH) has not been previously studied. We generated LOXL1fl/fl mice to selectively delete LOXL1 in hepatic stellate cells (HSCs) (LOXL1fl/flGfapcre; LOXL1fl/fl as littermate controls) and then examined liver pathology and metabolic profiles in LOXL1fl/flGfapcre fed with either a choline-deficient L-amino acid-defined (CDAA) diet or an isocaloric control diet for 16 weeks. Thereafter, the findings from the animal model were confirmed in 23 patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD). LOXL1 was significantly increased in CDAA induced non-obese NASH compared with the control diet, and LOXL1 deficient in HSCs ameliorated CDAA-induced inflammation and fibrosis, with reduced expression of pro-inflammation and pro-fibrogenic genes in the HSCs-specific LOXL1 knockout mice model. Interestingly, LOXL1 deficient in HSCs could attenuate hepatic steatosis and reverse the metabolic disorder by restoring adipose tissue function without altering the effect of hepatic lipogenesis gene expression in non-obese NASH model. More importantly, analyses of serum LOXL1 and leptin levels from NAFLD patients revealed that LOXL1 was positively correlated with histological fibrosis progression, whereas it was inversely correlated with leptin levels, especially in non-obese NAFLD patients. LOXL1 may contribute to fibrosis progression in non-obese NAFLD, and HSCs-specific knockout of LOXL1 attenuated liver steatosis, inflammation, fibrosis, , and improved lipid metabolic abnormalities. Hence, LOXL1 inhibition may serve as a new therapeutic strategy for NASH.
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hepatic stellate cells specific LOXL1 deficiency abrogates hepatic inflammation fibrosis and corrects lipid metabolic abnormalities in non obese nash mice
Social Science Research Network, 2021Co-Authors: Aiting Yang, Wei Chen, Xuzhen Yan, Jidong Jia, Xu Fan, Yiwen Shi, Tao Huang, Hong YouAbstract:Background & Aims: Lysyl oxidase-like-1 (LOXL1), a vital crosslinking enzyme in extracellular matrix (ECM) protein maintenance, is well established in fibrosis via mediating ECM stabilization. However, the potential role of LOXL1 in the pathogenesis of nonalcoholic steatohepatitis (NASH) has not been previously studied. Methods: We generated LOXL1 fl/fl mice to selectively delete LOXL1 in hepatic stellate cells (HSCs) (LOXL1fl/flGfapcre; LOXL1fl/fl as littermate controls) and then examined liver pathology and metabolic context in LOXL1fl/flGfapcre fed a choline-deficient L-amino acid-defined (CDAA) diet or an isocaloric control diet for 16 weeks. We confirmed study findings in 23 patients with biopsy-proven NAFLD. Results: LOXL1 was significantly increased in CDAA induced non-obese NASH compared with control diet. Here, utilizing a HSCs-specific deletion of LOXL1 model, we found that LOXL1 deficient in HSCs ameliorated CDAA-induced inflammation and fibrosis, with reduced expression of pro-inflammation and pro-fibrogenic genes. Interestingly, CDAA-fed LOXL1 deficient mice was associated with improved body weight and attenuated hepatic steatosis and to an up-regulation of leptin in adipose tissue and in serum, without changes in hepatic lipogenesis gene expression, compared with CDAA-fed control mice. Most importantly, analyses of serum LOXL1 and leptin levels from NAFLD patients revealed that LOXL1 was positively correlated with histological fibrosis progression, whereas was inversely correlated with leptin levels, especially in non-obese NAFLD patients. Conclusion: In a mouse model of CDAA-induced non-obese NASH, selective deletion of LOXL1 from HSCs attenuated steatohepatitis, hepatic fibrosis and improved lipid metabolic abnormalities. Hence, LOXL1 inhibition may serve as a new therapeutic strategy for NASH. Funding Statement: This study was supported by the National Natural Science Foundation of China (81670539 and 81500456). Declaration of Interests: The authors disclose no conflicts. Ethics Approval Statement: (Human) The Ethics Committee of Beijing Friendship Hospital approved study (No.: 2018-P2-228-02). (Animal) This study was approved by the Institutional Animal Care and Usage Committee of the Beijing Friendship Hospital, Capital Medical University, Beijing, China.
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Inhibition of lysyl oxidase-like 1 (LOXL1) expression arrests liver fibrosis progression in cirrhosis by reducing elastin crosslinking.
Biochimica et biophysica acta. Molecular basis of disease, 2018Co-Authors: Wenshan Zhao, Aiting Yang, Wei Chen, Ping Wang, Tianhui Liu, Min Cong, Xuzhen Yan, Jidong Jia, Hong YouAbstract:Mature crosslinked-poly-elastin deposition has been found to be associated with liver fibrosis. However, the regulation of crosslinked/insoluble elastin in liver fibrosis remains largely unknown. Here, we investigated the contribution of lysyl oxidases (LOXs) family, mediated elastin crosslinking, to liver fibrogenesis. We established carbon tetrachloride (CCl4)-induced liver fibrotic and cirrhotic models and found that crosslinked/insoluble elastin levels spiked only in cirrhosis stage during disease progression, in comparison to collagen Ι levels which increased continuously though all stages. Among the LOXs family members, only LOX-like 1 (LOXL1) levels were coincident with the appearance of crosslinked/insoluble elastin. These coincidences included that LOXL1 expression increased (34 fold) in cirrhosis, localized with α-smooth muscle actin (SMA) and was absent in normal and fibrotic livers. In LX-2 cells, LOXL1 silencing arrested expression of α-SMA, elastin and collagen Ι. Our previously characterized adeno-associated vector (AAV) 2/8 shRNA was shown to effectively downregulate LOXL1 expression in CCl4 induced fibrosis mice models. These resulted in delicate and thinner septa and less crosslinked elastin, with a 58% loss of elastin area and 51% decrease of collagen area. Our findings strongly suggested that elastin crosslinking and LOXL1 were co-associated with liver cirrhosis, while selective inhibition of LOXL1 arrested disease progression by reducing crosslinking of elastin.
