Project description:Osteoarthritis (OA) is the most common joint disease and is the leading cause of chronic disability among older people. Chondrocyte death was involved in OA pathogenesis. Ferroptosis is an iron-dependent cell death associated with peroxidation of lipids. Expression of GPX4 in the OA cartilage from OA patients were significantly lower than normal cartilage.In order to analyze the mechanism of GPX4, we conducted RNA-sequencing in mouse chondrocytes with or without GPX4 knockdown.Our results showed that Gpx4 downregulation could increase the sensitivity of chondrocytes to oxidative stress and aggravate ECM degradation in chondrocytes.
Project description:When using cell lines to study cancer, phenotypic similarity to the original tumor is paramount. Yet, little has been done to characterize how closely Merkel cell carcinoma (MCC) cell lines model native tumors. To determine their similarity to MCC tumor samples, we characterized MCC cell lines via gene expression microarrays. Using whole transcriptome gene expression signatures and a computational bioinformatic approach, we identified significant differences between variant cell lines (UISO, MCC13, and MCC26) and fresh frozen MCC tumors. Conversely, the classic WaGa and Mkl-1 cell lines more closely represented the global transcriptome of MCC tumors. When compared to publicly available cancer lines, WaGa and Mkl-1 cells were similar to other neuroendocrine tumors, but the variant cell lines were not. WaGa and Mkl-1 cells grown as xenografts in mice had histological and immunophenotypical features consistent with MCC, while UISO xenograft tumors were atypical for MCC. Spectral karyotyping and short tandem repeat analysis of the UISO cells matched the original cell line's description, ruling out contamination. Our results validate the use of transcriptome analysis to assess the cancer cell line representativeness and indicate that UISO, MCC13, and MCC26 cell lines are not representative of MCC tumors, whereas WaGa and Mkl-1 more closely model MCC. RNA was extracted from MCC cell lines and MCC and SCLC tumor samples and hybridized to Affymetrix microarrays for transcriptome profiling.
Project description:Podocytes are an integral part of the glomerular infiltration barrier. At present, many genes are known essential for podocyte survival and structural and functional homeostasis; however, there are more such genes to be uncovered. By single-cell RNA-seq of mouse podocytes, we detected the expression of gene encoding MCC regulator of WNT signaling pathway (MCC) in majority of the single podocytes and speculated that MCC may be essential for podocytes. We confirmed MCC expression in mouse podocytes and further showed its expression in human podocytes. To experimentally prove the essentiality of MCC for podocytes, we knocked down MCC in cultured podocytes, resulting in marked morphological change of cell shape, cytoskeletal stress fiber disruption, increased apoptosis, and downregulation of podocyte essential genes, CD2AP and WT1, demonstrating that MCC is essential for podocytes. To investigate the mechanism underlying the role of MCC in podocytes, we performed RNA-seq analysis of the podocytes in culture 24 hours after transfection of siRNA against MCC, followed by bioinformatics analysis of the genes with altered expression, and found some mechanistic clues. Lastly, we found that MCC is downregulated in podocytes treated with puromycin aminonucleosides and in glomeruli of diabetic mice and FSGS patients, implicating MCC in the development of podocytopathy and proteinuria. In conclusion, MCC is essential for podocytes and its deficiency may be involved in podocytopathy.
Project description:Gene expression profiling of primary mouse articular chondrocyte infected with recombinant adenovirus expressing mouse ZFP36 Ring Finger Protein Like 1(Zfp36l1) or recombinant adenovirus expressing mouse small hairpin RNA of Zfp36l1. In this study, we have attempted to explore the effects of Zfp36l1 gene overexpression or knockdown on mouse transcriptome and have identified numerous genes which are involved in osteoarthritis pathogenesis.
Project description:Gene expression profiling of primary mouse articular chondrocyte infected with recombinant adenovirus expression mouse Regnase-1 or recombinant adenovirus expressing mouse small hairpin RNA of Regnase-1. In this study, we have attempted to explore the effects of Regnase-1 overexpression or knockdown on mouse transcriptome and have identified numerous genes which are involved in osteoarthritis pathogenesis.
Project description:Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cancer of the skin, caused by either excessive UV damage or integration of the Merkel cell polyomavirus (MCV) genome. Here, we report that virally encoded MCV small T antigen (ST) establishes dependence on the LSD1 transcriptional repressor. Inhibition of LSD1 reduces growth of MCV-positive MCC and suppresses ST’s transformation capacity in vitro and in vivo. To define the mechanism of LSD1 inhibition in MCC, we performed a CRISPR loss-of-function library screen. We found that deletion of components of the non-canonical (ncBAF) chromatin remodeler complex confers resistance to LSD1 inhibitors and that LSD1 and ncBAF antagonistically regulate an overlapping set of genes involved in neuron differentiation. Our work provides mechanistic insight into the dependence of MCC on LSD1 and the role of ncBAF as a tumor suppressor in cancer.
Project description:When using cell lines to study cancer, phenotypic similarity to the original tumor is paramount. Yet, little has been done to characterize how closely Merkel cell carcinoma (MCC) cell lines model native tumors. To determine their similarity to MCC tumor samples, we characterized MCC cell lines via gene expression microarrays. Using whole transcriptome gene expression signatures and a computational bioinformatic approach, we identified significant differences between variant cell lines (UISO, MCC13, and MCC26) and fresh frozen MCC tumors. Conversely, the classic WaGa and Mkl-1 cell lines more closely represented the global transcriptome of MCC tumors. When compared to publicly available cancer lines, WaGa and Mkl-1 cells were similar to other neuroendocrine tumors, but the variant cell lines were not. WaGa and Mkl-1 cells grown as xenografts in mice had histological and immunophenotypical features consistent with MCC, while UISO xenograft tumors were atypical for MCC. Spectral karyotyping and short tandem repeat analysis of the UISO cells matched the original cell line's description, ruling out contamination. Our results validate the use of transcriptome analysis to assess the cancer cell line representativeness and indicate that UISO, MCC13, and MCC26 cell lines are not representative of MCC tumors, whereas WaGa and Mkl-1 more closely model MCC.
Project description:Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cancer of the skin, caused by either excessive UV damage or integration of the Merkel cell polyomavirus (MCV) genome. Here, we report that virally encoded MCV small T antigen (ST) establishes dependence on the LSD1 transcriptional repressor. Inhibition of LSD1 reduces growth of MCV-positive MCC and suppresses ST’s transformation capacity in vitro and in vivo. To define the mechanism of LSD1 inhibition in MCC, we performed a CRISPR loss-of-function library screen. We found that deletion of components of the non-canonical (ncBAF) chromatin remodeler complex confers resistance to LSD1 inhibitors and that LSD1 and ncBAF antagonistically regulate an overlapping set of genes involved in neuron differentiation. Our work provides mechanistic insight into the dependence of MCC on LSD1 and the role of ncBAF as a tumor suppressor in cancer.
Project description:Merkel cell carcinoma (MCC) is a highly aggressive, neuroendocrine skin cancer that lacks actionable mutations, which could be utilized for targeted therapies. Epigenetic regulators governing cell identity may represent unexplored therapeutic entry points. Here, we targeted epigenetic regulators in a pharmacological screen and discovered that the lysine-specific histone demethylase 1A (LSD1/KDM1A) is required for MCC growth in vitro and in vivo. We show that LSD1 inhibition in MCC disrupts the LSD1-CoREST complex leading to displacement and degradation of HMG20B (BRAF35), a poorly characterized complex member that is essential for MCC proliferation. Inhibition of LSD1 causes derepression of transcriptional master regulators of the neuronal lineage, activates a gene expression signature resembling normal Merkel cells, and induces cell cycle arrest and cell death. Our study unveils the importance of LSD1 for proliferation and maintaining cell identity in MCC. There is growing evidence that cancer cells exploit cellular plasticity and dedifferentiation programs to evade destruction by the immune system. The combination of LSD1 inhibitors with checkpoint inhibitors may thus represent a promising treatment strategy for MCC patients.
Project description:Merkel cell carcinoma (MCC) is a highly aggressive, neuroendocrine skin cancer that lacks actionable mutations, which could be utilized for targeted therapies. Epigenetic regulators governing cell identity may represent unexplored therapeutic entry points. Here, we targeted epigenetic regulators in a pharmacological screen and discovered that the lysine-specific histone demethylase 1A (LSD1/KDM1A) is required for MCC growth in vitro and in vivo. We show that LSD1 inhibition in MCC disrupts the LSD1-CoREST complex leading to displacement and degradation of HMG20B (BRAF35), a poorly characterized complex member that is essential for MCC proliferation. Inhibition of LSD1 causes derepression of transcriptional master regulators of the neuronal lineage, activates a gene expression signature resembling normal Merkel cells, and induces cell cycle arrest and cell death. Our study unveils the importance of LSD1 for proliferation and maintaining cell identity in MCC. There is growing evidence that cancer cells exploit cellular plasticity and dedifferentiation programs to evade destruction by the immune system. The combination of LSD1 inhibitors with checkpoint inhibitors may thus represent a promising treatment strategy for MCC patients.