Project description:Hepatitis B virus (HBV) is a leading cause of liver-related diseases and mortality. However, immune mechanisms governing the phases of HBV infection remain elusive. Understanding molecular components in hepatitis immunosuppression and progression is essential for developing immunotherapies for functional cure of chronic HBV infection. Our integrative analysis of intrahepatic tissue and peripheral PBMC samples from patients with acute and chronic HBV infection using single-cell RNA sequencing (scRNA-seq) and TCR/BCR sequencing (scTCR/BCR-seq) revealed three distinct lineages of PBMC-derived intrahepatic T lymphocytes (hpCTLs): exhausted GZMK+PDCD1+, short-lived effector KLRG1+, and inactivated GZMB+PRF1+ hpCTLs. Key factors such as FasL/Fas-mediated cytotoxicity, CD28 co-stimulation, and exhaustion status were identified as determinants of hpCTL functionality. Liver-resident DC-SIGN+ macrophages were found to act as antigen-presenting cells that cross-prime hpCTLs in response to IL-2 or as suppressive macrophages by inhibiting T cell immunity through IL-10 and PD-L1 production and Treg recruitment. The intrahepatic core cellular network, including DC-SIGN+ macrophages, CSF1+ST2+ mast cells, AREG+ liver-resident NK cells, CD14+ hepatocytes, and CXCL13+ TFH, was observed to modulate immune tolerance, activation, and suppression in HBV infection. This study inferred the core cellular network involved in immune phenotype switching across different hepatitis B phases and suggested potential immunomodulatory strategies for treating chronic HBV infection.
Project description:Hepatitis C Virus (HCV) core protein plays a major role in HCV mediated liver pathologies. We have previously reported that HCV core variants isolated from tumoral (T) and non-tumoral (NT) livers were capable to alleviate Smad transcriptional activity and to shift TGF-β responses from tumor suppressor effects to tumor promotion. To comprehensively appreciate the consequences of core-mediated deregulation of Smad signaling on TGF-b target gene expression, Affimetrix microarrays were performed. Microarray analyses demonstrate that HCV core expression in hepatocytes modulates TGF-b target gene expression. Furthermore, most of the genes modulated in core expressing hepatocytes after TGF-b treatment were already regulated in these non treated cells suggesting that HCV core is capable to activate latent TGF-b. Transcriptome analysis was performed on primary hepatocytes from transgenic mice expressing either Core T or core NT or their control littermates treated or not with TGF-b.
Project description:Hepatitis C Virus (HCV) core protein plays a major role in HCV mediated liver pathologies. We have previously reported that HCV core variants isolated from tumoral (T) and non-tumoral (NT) livers were capable to alleviate Smad transcriptional activity and to shift TGF-β responses from tumor suppressor effects to tumor promotion. To comprehensively appreciate the consequences of core-mediated deregulation of Smad signaling on TGF-b target gene expression, Affimetrix microarrays were performed. Microarray analyses demonstrate that HCV core expression in hepatocytes modulates TGF-b target gene expression. Furthermore, most of the genes modulated in core expressing hepatocytes after TGF-b treatment were already regulated in these non treated cells suggesting that HCV core is capable to activate latent TGF-b.
Project description:In melanoma, a switch from a proliferative melanocytic to an invasive mesenchymal phenotype is based on dramatic transcriptional reprogramming which involves complex interactions between a variety of signaling pathways and their downstream transcriptional regulators. TGFb/SMAD, Hippo/YAP/TAZ and Wnt/b-catenin signaling pathways are major inducers of transcriptional reprogramming and converge at several levels. Here, we report that TGFb/SMAD, YAP/TAZ and b-catenin are all required for a proliferative-to-invasive phenotype switch. Loss and gain of function experimentation, global gene expression analysis, and computational nested effects models revealed the hierarchy between these signaling pathways and identified shared target genes. SMAD-mediated transcription at the top of the hierarchy leads to the activation of YAP/TAZ and of b-catenin, with YAP/TAZ governing an essential sub-program of TGFb-induced phenotype switching. Wnt/b-catenin signaling is situated further downstream and exerts a dual role: it promotes the proliferative, differentiated melanoma cell phenotype and it is essential but not sufficient for SMAD or YAP/TAZ-induced phenotype switching. The results identify epistatic interactions among the signaling pathways underlying melanoma phenotype switching and highlight the priorities in targets for melanoma therapy.