Cellular signalling最新文献

Liver disease is a global health problem responsible for more than two million deaths annually. Metabolic dysfunction-associated steatotic liver disease (MASLD) and alcohol-associated liver disease (ALD) are major contributors to chronic liver disease-related morbidity and mortality. Factors like diet and alcohol consumption have become key drivers of liver pathologies including steatosis, fibrosis/cirrhosis, and hepatocellular carcinoma. To date very few treatments are available, hence there is a critical need for the development of novel therapies to slow down the development/progression of liver damage. The long non-coding RNA H19 gene, H19, is an imprinted gene normally expressed from the maternally inherited chromosome and epigenetically silenced in the paternal chromosome. At the embryo stage H19 controls genome-wide methylation, directs the methylation of the imprinted gene network, and regulates organ size. In the livers of neonates, H19 is important for organ maturation but remains silent in the mature organ. H19 re-expression in the adult liver drives de novo lipogenesis and fibrosis and maintains a proliferative state in tumor cells. The complexity of H19 functions in the liver is reflected in its interaction and regulation of a growing number of proteins, and coding and non-coding RNAs involved in metabolism, pro-fibrotic gene networks, cell cycle progression, and chromatin regulation. This review summarizes the findings related to the role of H19 in liver development and in diseases such as fatty liver, fibrosis, and hepatocellular carcinoma.

Intestinal epithelial cells (IECs) injury and intestinal barrier function impairment are key risk factors for the pathogenesis and progression of inflammatory bowel disease (IBD). Heterogeneous nuclear ribonucleoprotein A2B1 (A2B1), as an N6-methyladenosine (m6A)-binding protein, is upregulated in intestinal epithelial cells of IBD patients. However, the role of m6A modifications and A2B1 in intestinal epithelial cell damage and intestinal barrier dysfunction remains largely unexplored. This study confirmed that A2B1 was significantly upregulated in IECs and tissues in IBD. Elevated expression of A2B1 was also found in tumor necrosis factor alpha (TNF-α) induced Caco-2 cells, intestinal organoids and dextran sulfate sodium (DSS) induced mouse model colon tissues. Overexpression of A2B1 in IECs led to increased apoptosis and barrier dysfunction, while knockdown of A2B1 ameliorated these effects. A2B1 interacted with TNF-related apoptosis inducing ligand (TRAIL) in an m6A dependent manner and regulated intestinal epithelial cell apoptosis and barrier function by modulating TRAIL expression. 1,2,3,6-Tetragalloylglucose (TeGG) was identified as a potent inhibitor of A2B1, effectively blocking TNF-α induced TRAIL upregulation and barrier damage in both cellular and organoid models. The study results suggest that A2B1 plays a crucial role in IBD by modulating TRAIL mRNA, leading to IECs apoptosis and intestinal barrier dysfunction. Targeting the A2B1-TRAIL interaction with small-molecule inhibitors like TeGG offers a novel and promising therapeutic approach for the treatment of IBD.

Tumor-associated fibroblast-mediated matrix remodeling is an important feature of invasive immune-rejection bladder cancer, but its pathogenic mechanism and potential therapeutic targets are still unclear. The matrix and immune interaction network and core related genes in bladder cancer were systematically investigated by combining single-cell transcriptome data analysis and fibroblast GWAS data with TCGA and GEO data deconvolution, WGCNA, drug response prediction, multiplex immunofluorescence, and in vitro and in vivo validation experiments of cells and animals. ADAM12's functional validation. The findings demonstrated that the tumor-associated fibroblast ECM-CAF subgroup infiltration was evident in bladder cancer and was substantially associated with the upregulation of the core genes ADAM12 and TP53-biased basal-like program. These were characterized by the deposition of dense matrix, the upregulation of numerous immune checkpoints, the rejection and dysfunction of T cells, and a decrease in immunogenicity. Multiplex immunofluorescence localization of bladder cancer and normal bladder tissue showed that ADAM12 was significantly associated with the progression of non-muscle invasive bladder cancer to muscle invasive bladder cancer and the infiltration of ECM-CAF. Knockdown of ADAM12 inhibited the proliferation, migration, and invasion of bladder cancer cells, reduced the activation of the PI3K-AKT-mTOR pathway, and inhibited bladder cancer xenograft growth and lung metastasis. ADAM12 overexpression triggered the PI3K-AKT-mTOR pathway, enhanced the development and lung metastasis of bladder cancer xenografts, and markedly increased the invasion, migration, and proliferation of bladder cancer cells. The above results indicate that ADAM12, as a matrix-driven factor, links matrix remodeling, PI3K-AKT signaling pathway and bladder cancer immunosuppression, and has good prognostic and therapeutic stratification potential, providing new ideas for precision targeted intervention and treatment of bladder cancer.

Objective: To investigate the role of salt induced kinases 1 (SIK1) in osteoarthritis (OA)-related cartilage damage and its underlying metabolic mechanisms.

Methods: An OA mouse model was established using destabilization of the medial meniscus (DMM) technique. Pathological changes in cartilage tissue were evaluated using hematoxylin-eosin staining (HE) and safranin O-fast green staining. SIK1 expression levels in OA mice were assessed using immunohistochemistry and Western blot analysis. Metabolomic analysis revealed differential metabolites and signaling pathways between normal and OA mice. An adeno-associated virus (AAV) overexpressing SIK1 was constructed and used to transfect interleukin-1β (IL-1β) induced chondrocytes. Chondrocyte survival rate, DNA damage, inflammatory response, matrix degradation, and metabolic markers were assessed using CCK8 assays, immunofluorescence, ELISA, and Western blot. Subsequently, arachidonic acid (AA) was introduced to activate specific metabolic pathways, and in vivo changes in cartilage damage and metabolic homeostasis were evaluated.

Results: SIK1 expression was significantly downregulated in the cartilage of OA mice. Compared with the Model group, SIK1 overexpression significantly improved cartilage degeneration, reduced extracellular matrix (ECM) degradation, and lowered the Mankin score. Metabolomic analysis revealed significant activation of the AA metabolic pathway in the OA model group. SIK1 overexpression protected chondrocytes from IL-1β-induced apoptosis and inflammation. It also maintained ECM balance by increasing collagen II and aggrecan while decreasing matrix metallopeptidase 13 (MMP13). Mechanistically, AA intervention reversed the protective effects of SIK1 overexpression against OA chondrocyte injury.

Conclusion: SIK1 ameliorated OA-related cartilage damage by inhibiting AA metabolic pathway.

Background: Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive malignancy with poor prognosis. Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) drive tumor progression through complex cellular interactions; however, the key functional molecules and underlying mechanisms of CAFs in HNSCC remain unclear.

Methods: We employed single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) to characterize the heterogeneity of the HNSCC TME. Survival analysis, immune infiltration assessment and immune treatment response evaluation were evaluated based on TCGA and multiple GEO cohorts. Key findings were further validated through a series of functional experiments in vitro and in vivo.

Results: Multimodal omics analysis revealed that CTHRC1 expression was specifically enriched in the CAFs subpopulation. These CTHRC1⁺ CAFs were spatially co-localized with regions exhibiting epithelial-mesenchymal transition (EMT) and angiogenesis signatures in HNSCC. High infiltration of CTHRC1⁺ CAFs was significantly associated with poor patient prognosis. The tumor immune dysfunction and exclusion (TIDE) analysis indicated that high expression of CTHRC1 was associated with immunosuppression and adverse reactions to immunotherapy. Functional studies demonstrated that CAFs-secreted CTHRC1 directly binds to ITGA5 on tumor cells, activating the PI3K/AKT signaling pathway, thereby promoting proliferation, EMT, and angiogenesis in HNSCC.

Conclusions: This study has confirmed that CTHRC1⁺ CAFs facilitate HNSCC malignancy via the ITGA5/PI3K/AKT signaling axis. These findings highlight CTHRC1 as a potential prognostic biomarker and therapeutic target in HNSCC.

Osteoclasts function as the primary effectors of bone resorption and are essential for bone homeostasis. Krüppel-like factor 2 (KLF2) has been implicated in osteoclast differentiation, but its precise mechanism remains poorly understood. In this study, we aimed to investigate the role of KLF2 in osteoclast function by characterising osteoclastogenesis, maturation and activity and to explore the underlying biomechanism. We showed that KLF2 negatively regulates osteoclastogenesis by characterising the osteoclast number, size and protein markers; that it negatively regulates osteoclast maturation by characterising the formation of intact actin rings and punctured podosome clusters; and that it negatively regulates osteoclast activity by characterising intracellular acidification through KLF2 overexpression by lentiviral transfection and KLF2 knockdown by small interfering RNA (siRNA) transfection. The results of chromatin immunoprecipitation (ChIP) and co-immunoprecipitation (Co-IP) assays revealed that KLF2 directly interacted with c-Fos and c-Jun, which together constitute the activator protein-1 (AP-1) complex. By overexpressing KLF2 and knockdown with si-KLF2, we revealed that KLF2 mediated osteoclast function via negative regulation of the AP-1 complex. The inhibition of AP-1 activity confirmed its importance in KLF2-mediated osteoclast differentiation; Moreover, the inhibition of JNK signalling decreased the AP-1 activation induced by KLF2 knockdown, indicating the importance of the RANKL-MAPK-AP-1-NFATc1 axis in KLF2-regulated osteoclast differentiation. This study reveals a typical type of negative regulation of osteoclasts by KLF2 and provides information for potential therapeutic targets in osteolytic diseases, including osteoporosis.

Our previous studies demonstrated that extracellular vesicles (EVs) derived from quiescent hepatic stellate cells (HSC-EVs) exert protective effects against oxidative injury to hepatocytes. In this study, we aimed to clarify the hepatoprotective mechanisms of action of HSC-EVs. By RNA sequencing, circPVT1 was identified as a highly abundant circular RNA in HSC-EVs. Functionally, we observed that circPVT1 knockdown abolished the beneficial effects of HSC-EVs in improving liver function and increasing the proliferation and reducing the apoptosis of hepatocytes in a H₂O₂-treated hepatocyte model and in a CCL₄-induced liver injury rat model via delivering circPVT1. Bioinformatics analysis and dual luciferase assays revealed that circPVT1 acts as a molecular sponge for miR-125b-5p. Through a series of loss-and-gain experiments, we confirmed that circPVT1 increased the proliferation and reduced the apoptosis of hepatocytes through the inhibition of miR-125b-5p expression. Furthermore, rescue experiments revealed that silencing BCL2L2, a target gene of miR-125b-5p, prevented the enhancement of hepatoprotection by HSC-EVs combined with miR-125b-5p inhibition. These findings demonstrate that HSC-EVs are potential therapeutic vesicles that can protect against oxidative injury to hepatocytes through the activation of the circPVT1/miR-125b-5p/BCL2L2 signalling pathway.

α-Synuclein (α-syn) aggregate-mediated loss of dopaminergic neurons play a critical role in the mechanisms mediating Parkinson's disease (PD). While neuroinflammation is invariably associated with several neurodegenerative disorders, emerging reports on the N- and C-terminus epitopes of α-syn in inducing activated T-cells/microglia garnered much attention. Interestingly, differential expression of isoforms of α-syn with altered N- and C-terminus regions were also noticed in PD subjects; however, their role in the activation of T-cells is not yet known. Hence, we sought to investigate the effect of monomeric and aggregated α-syn-spliced isoforms on activation of T-cells. Our results indicate that, as compared to monomeric forms, stereotaxic administration of PFFs of Wild Type (WT-syn) and 112-syn-induced significant loss of SNPc dopamine neurons and motor coordination. Further, the expression of CD4⁺ and CD8⁺ T-cells was significantly elevated by PFFs of WT and 112-syn as compared to their corresponding monomers. Peripheral blood mononuclear cells (PBMCs) isolated from mice administered with PFFs exhibited increased cytokine responses upon stimulation with peptides corresponding to the C-terminus region of WT-syn and 112-syn, suggesting their antigenic potential in the order WT-syn < 112-syn. This enhanced antigenicity of 112-syn indicate that the spliced α-syn isoforms, particularly 112-syn, could play a critical role in immune activation in PD, highlighting splice junctions as potential targets for therapeutic strategies.