Distinct role of perlecan plays in mesenchymal tissue regeneration through genetic and epigenetic modification
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ABSTRACT: Perlecan is a critical component of basement membrane proteins in tissue development. However, there are few studies investigating direct impact of perlecan on mesenchymal tissue differentiation using genetic modification (gain- and loss-of-function mutations) and epigenetic modification (matrix microenvironment). In this report, Cas9-mediated knockout (KO) of heparin sulfate proteoglycan 2 (HSPG2) and overexpression (OE) in human fetal nucleus pulposus stem/progenitor cells (NPSCs) and adult infrapatellar fat pad-derived stem cells (IPFSCs) were evaluated for the influence on mesenchymal differentiation. Furthermore, decellularized ECM (dECM) deposited by fetal NPSCs with either HSPG2 KO or OE was evaluated for its rejuvenation effect on adult NPSCs in proliferation and mesenchymal differentiation. We found that adult IPFSCs confirmed the unique role of perlecan in mesenchymal differentiation of fetal NPSCs; dECM with perlecan overexpression significantly promoted adult NPSCs in chondrogenic capacity rather than osteogenic and adipogenic capacities, indicating a potential application of perlecan in engineering smart biomaterial for cartilage regeneration.
Project description:Perlecan (HSPG2), a multifunctional heparan sulphate proteoglycan (HSPG), is a key player in extracellular matrix maturation and stabilisation. Structurally perlecan is similar to agrin, another HSPG known to contribute to cardiomyocyte phenotype switching by reverting hypertrophy. Although perlecan is crucial for cardiac development, its role in cardiomyocyte phenotypic switching is unknown. Here we show perlecan expression increases over time during the differentiation of pluripotent stem cells to cardiomyocytes (hPSC-CMs). Haploinusuffient hPSCs (HSPG2+/-) differentiate efficiently towards cardiomyocytes with minimal transcriptomic differences seen early in differentiation, but wide-ranging changes seen in late-stage cardiomyocytes. These differences are associated with structural, contractile, metabolic, and ECM genes. In keeping, late-stageHSPG2+/-hPSC-CMs display reduced maximal metabolic capacity and increased extracellular acidification rate, characteristics of reduced maturity. Moreover, engineered heart tissues produced withHSPG2+/-hPSC-CMs exhibit increased ECM remodelling, reduced tissue thickness and force generation. Wild-type hPSC-CMs grown on a substrate coated with a perlecan peptide showed increased cardiomyocyte nucleation typical of hypertrophic growth, suggesting that perlecan plays the opposite role of agrin by promoting cellular maturation rather than hyperplasia and proliferation. These data show that perlecan promotes cardiomyocyte maturity, possibly through hypertrophic growth. Targeting perlecan-dependent signalling may, therefore, reverse the phenotypic switch common to many forms of heart failure, by improving cardiomyocyte functionality.
Project description:Stem cells reside in specialised microenvironments or niches that balance stem cell proliferation and differentiation. The extracellular matrix (ECM) is an essential component of most niches, as it controls niche homeostasis, provides physical support and conveys extracellular signals. Basement membranes (BMs) are thin ECM sheets constituted mainly by Laminins, Perlecan, Collagen IV and Entactin/Nidogen and that surround epithelia and other tissues. Perlecans are secreted proteoglycans that interact with ECM proteins, ligands, receptors and growth factors such as FGF, PDGF, VEGF, Hedgehog and Wingless. Thus, Perlecans have structural and signalling functions through the binding, storage or sequestering of specific ligands. We have used the Drosophila ovary to assess the importance of Perlecan in the functioning of a stem cell niche. Ovarioles in the adult ovary are enveloped by an ECM sheath and possess a tapered structure at their anterior apex termed the germarium. The anterior tip of the germarium hosts the germline niche, where two to four germline stem cells (GSCs) reside together with few somatic cells: terminal filament (TF) cells, cap cells (CpCs) and escort cells (ECs). We report that niche architecture in the developing gonad requires trol, that niche cells secrete an isoform-specific, Perlecan-rich interstitial matrix and that DE-cadherin-dependent stem cell-niche adhesion necessitates trol. Hence, we provide evidence to support a structural role for Perlecan in germline niche establishment during larval stages and in the maintenance of a normal pool of stem cells in the adult niche.
Project description:Perlecan (HSPG2) signalling promotes structural, contractile, and metabolic development during the maturation stage of hPSC-CM differentiation
Project description:Chronic hepatitis B virus (HBV) remains to be the most common risk factor of hepatocellular carcinoma (HCC). While work has primarily focussed on understanding the direct and indirect mechanisms of Hepatitis B virus X protein (HBx) mediated hepatocarcinogenesis, from genetic and epigenetic perspectives, its influence on RNA modification mediated onset of liver malignancies is less well understood. This study explored the role of HBV-encoded HBx in altering the m6A methylome profile and its implications on the pathogenesis of HCC. We established HBx expressing stable HCC cell lines, Huh7-HBx and HepG2-HBx, and explored the transcriptomic and epitranscriptomic profiles by RNA-seq and MeRIP-seq, respectively. Preliminary results suggest that HBx promotes liver cell proliferation, migration, survival and overall m6A methylation in HCC cells and is involved in modulating the extracellular matrix. We show that HBx mediates liver cell transformation by upregulating KIAA1429 methyltransferase. HBx also drives the expression and hypermethylation of the extracellular matrix protein HSPG2/Perlecan and promotes tumourigenesis. Our findings indicate a potential interaction between KIAA1429 and HSPG2, thus could be novel targets in combating HBx-driven HCC and warrants further investigation.
Project description:Chronic hepatitis B virus (HBV) remains to be the most common risk factor of hepatocellular carcinoma (HCC). While work has primarily focussed on understanding the direct and indirect mechanisms of Hepatitis B virus X protein (HBx) mediated hepatocarcinogenesis, from genetic and epigenetic perspectives, its influence on RNA modification mediated onset of liver malignancies is less well understood. This study explored the role of HBV-encoded HBx in altering the m6A methylome profile and its implications on the pathogenesis of HCC. We established HBx expressing stable HCC cell lines, Huh7-HBx and HepG2-HBx, and explored the transcriptomic and epitranscriptomic profiles by RNA-seq and MeRIP-seq, respectively. Preliminary results suggest that HBx promotes liver cell proliferation, migration, survival and overall m6A methylation in HCC cells and is involved in modulating the extracellular matrix. We show that HBx mediates liver cell transformation by upregulating KIAA1429 methyltransferase. HBx also drives the expression and hypermethylation of the extracellular matrix protein HSPG2/Perlecan and promotes tumourigenesis. Our findings indicate a potential interaction between KIAA1429 and HSPG2, thus could be novel targets in combating HBx-driven HCC and warrants further investigation.
Project description:As a tissue-specific stem cell for chondrogenesis, synovium-derived stem cells (SDSCs) are a promising cell source for cartilage repair. However, a small biopsy can only provide a limited number of cells. Cell senescence from both in vitro expansion and donor age presents a big challenge for stem cell based cartilage regeneration. Here we found that expansion on decellularized extracellular matrix (dECM) full of three-dimensional nanostructured fibers provided SDSCs with unique surface profiles, low elasticity but large volume as well as fibroblast-like shape. dECM expanded SDSCs yielded large pellets with intensive staining of type II collagen and sulfated GAGs, which was supported by both biochemical data and real-time PCR results. Our results also hint at lower levels of inflammatory genes and how they might be responsible for enhanced chondrogenic differentiation in dECM expanded SDSCs. Despite an increase of type X collagen in chondrogenically induced cells, dECM expanded cells had significantly lower potential for endochondral bone formation. Both Wnt and MAPK signals were actively involved in both expansion and chondrogenic induction of dECM expanded cells. dECM expanded human SDSCs could be a potential cell source for autologous cartilage repair Adult human synovial fibroblasts (4 donors, two male and two female, average 43 years old, all had no known joint disease) were grown for one passage on plastic flasks (P cells) or plastic flasks pre-coated with decellularized extracellular matrix (E cells). Aliquots were centrifuged and pellets cultured for 35 days in serum-free chondrogenic medium (P pellet or E pellet). There are no replicates.
Project description:Hepatitis B virus X protein contributes to hepatocellular carcinoma via upregulation of KIAA1429 methyltransferase and mRNA m6A hypermethylation of HSPG2/Perlecan
Project description:Naïve pluripotent stem cells (nPSCs) correspond to nascent epiblast in the pre-implantation embryo. nPSCs from mouse and human differ in self-renewal requirements and potency for trophectoderm generation. Here we investigated chimpanzee (Pan troglodytes) nPSCs. Naïve type colonies emerged after resetting or reprogramming but failed to expand. We found that the block to self-renewal is overcome by inhibition of EZH2, the enzymatic component of Polycomb repressor group 2 (PRC2). Chimpanzee nPSCs are euploid, produce teratomas, and can be capacitated for somatic lineage differentiation in vitro. They show transcriptome relatedness to human nPSCs and early epiblast, with shared expression of a subset of pluripotency transcription factors. Chimpanzee nPSCs differentiate to trophectoderm and form tri-lineage blastoids. We confirmed that PRC2 suppresses self-renewal by genetic deletions. Furthermore, we demonstrate that EZH2 inhibition facilitates feeder-free propagation of human nPSCs. In summary, chimpanzee nPSCs expand the repertoire of systems for studying primate pluripotency and early embryogenesis.
Project description:Naïve pluripotent stem cells (nPSCs) correspond to nascent epiblast in the pre-implantation embryo. nPSCs from mouse and human differ in self-renewal requirements and potency for trophectoderm generation. Here we investigated chimpanzee (Pan troglodytes) nPSCs. Naïve type colonies emerged after resetting or reprogramming but failed to expand. We found that the block to self-renewal is overcome by inhibition of EZH2, the enzymatic component of Polycomb repressor group 2 (PRC2). Chimpanzee nPSCs are euploid, produce teratomas, and can be capacitated for somatic lineage differentiation in vitro. They show transcriptome relatedness to human nPSCs and early epiblast, with shared expression of a subset of pluripotency transcription factors. Chimpanzee nPSCs differentiate to trophectoderm and form tri-lineage blastoids. We confirmed that PRC2 suppresses self-renewal by genetic deletions. Furthermore, we demonstrate that EZH2 inhibition facilitates feeder-free propagation of human nPSCs. In summary, chimpanzee nPSCs expand the repertoire of systems for studying primate pluripotency and early embryogenesis.