TLN1 contains a cancer-associated cassette exon that alters talin-1 mechanosensitivity

CREB1 promotes cholangiocarcinoma metastasis through transcriptional regulation of the LAYN-mediated TLN1/β1 integrin axis: CREB1 promotes cholangiocarcinoma metastasis through regulating LAYN/TLN1/β1 integrin axis

Background

Layilin (LAYN) plays an important role in tumor progression, invasion, and metastasis; however, its role in cholangiocarcinoma (CHOL) has not been elucidated.

Methods

We utilized the GEPIA, STRING, and hTFtarget databases for bioinformatics analysis. Overexpression or knockdown cell lines were constructed by transfecting the cells with different plasmids. Western blot (WB) was performed to detect LAYN, TLN1, and CREB1 expression. Cell proliferation, migration, and invasiveness were assessed using CCK-8 and Transwell assays. Immunofluorescence and WB were used to detect epithelial-mesenchymal transition (EMT) markers. The CHOL metastasis model was established by injecting RBE cells into the tail veins of nude mice. Metastatic lesions were identified using hematoxylin and eosin staining. Co-immunoprecipitation and Chromatin immunoprecipitation were used to validate the interactions.

Results

LAYN was highly expressed in the CHOL cells. Knockdown of LAYN significantly inhibited proliferation, migration, invasion, and EMT in both QBC-939 and RBE human CHOL cells, while overexpression of LAYN had the opposite effect. Furthermore, in a CHOL metastasis model using nude mice, knocking down LAYN expression markedly suppressed CHOL liver and lung metastases. LAYN interacts with TLN1, and CREB1 binds to the LAYN promoter, with all three showing a positive correlation. Additionally, bioinformatics analysis revealed high expression of both TLN1 and CREB1 in CHOL. Knockdown of TLN1 or CREB1 in QBC-939 and RBE cells inhibited cell proliferation, migration, invasion, and EMT, reversing the effects of LAYN overexpression. Moreover, knockdown of TLN1 or CREB1 also suppressed the expression of ITGB1 and the phosphorylation levels of c-Jun, p38 MAPK, and ERK, further reversing the effects of LAYN overexpression.

Conclusion

Our results suggest that CREB1 promotes CHOL metastasis through transcriptional regulation of the LAYN-mediated TLN1/β1 integrin axis.

Cellular stiffness sensing through talin 1 in tissue mechanical homeostasis

Tissue mechanical properties are determined mainly by the extracellular matrix (ECM) and actively maintained by resident cells. Despite its broad importance to biology and medicine, tissue mechanical homeostasis remains poorly understood. To explore cell-mediated control of tissue stiffness, we developed mutations in the mechanosensitive protein talin 1 to alter cellular sensing of ECM. Mutation of a mechanosensitive site between talin 1 rod-domain helix bundles R1 and R2 increased cell spreading and tension exertion on compliant substrates. These mutations promote binding of the ARP2/3 complex subunit ARPC5L, which mediates the change in substrate stiffness sensing. Ascending aortas from mice bearing these mutations showed less fibrillar collagen, reduced axial stiffness, and lower rupture pressure. Together, these results demonstrate that cellular stiffness sensing contributes to ECM mechanics, directly supporting the mechanical homeostasis hypothesis and identifying a mechanosensitive interaction within talin that contributes to this mechanism.

Unraveling pathogenesis, biomarkers and potential therapeutic agents for endometriosis associated with disulfidptosis based on bioinformatics analysis, machine learning and experiment validation

BACKGROUND

Endometriosis (EMs) is an enigmatic disease of yet-unknown pathogenesis. Disulfidptosis, a novel identified form of programmed cell death resulting from disulfide stress, stands a chance of treating diverse ailments. However, the potential roles of disulfidptosis-related genes (DRGs) in EMs remain elusive. This study aims to thoroughly explore the key disulfidptosis genes involved in EMs, and probe novel diagnostic markers and candidate therapeutic compounds from the aspect of disulfidptosis based on bioinformatics analysis, machine learning, and animal experiments.

RESULTS

Enrichment analysis on key module genes and differentially expressed genes (DEGs) of eutopic and ectopic endometrial tissues in EMs suggested that EMs was closely related to disulfidptosis. And then, we obtained 20 and 16 disulfidptosis-related DEGs in eutopic and ectopic endometrial tissue, respectively. The protein-protein interaction (PPI) network revealed complex interactions between genes, and screened nine and ten hub genes in eutopic and ectopic endometrial tissue, respectively. Furthermore, immune infiltration analysis uncovered distinct differences in the immunocyte, human leukocyte antigen (HLA) gene set, and immune checkpoints in the eutopic and ectopic endometrial tissues when compared with health control. Besides, the hub genes mentioned above showed a close correlation with the immune microenvironment of EMs. Furthermore, four machine learning algorithms were applied to screen signature genes in eutopic and ectopic endometrial tissue, including the binary logistic regression (BLR), the least absolute shrinkage and selection operator (LASSO), the support vector machine-recursive feature elimination (SVM-RFE), and the extreme gradient boosting (XGBoost). Model training and hyperparameter tuning were implemented on 80% of the data using a ten-fold cross-validation method, and tested in the testing sets which determined the excellent diagnostic performance of these models by six indicators (Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, Accuracy, and Area Under Curve). And seven eutopic signature genes (ACTB, GYS1, IQGAP1, MYH10, NUBPL, SLC7A11, TLN1) and five ectopic signature genes (CAPZB, CD2AP, MYH10, OXSM, PDLIM1) were finally identified based on machine learning. The independent validation dataset also showed high accuracy of the signature genes (IQGAP1, SLC7A11, CD2AP, MYH10, PDLIM1) in predicting EMs. Moreover, we screened 12 specific compounds for EMs based on ectopic signature genes and the pharmacological impact of tretinoin on signature genes was further verified in the ectopic lesion in the EMs murine model.

CONCLUSION

This study verified a close association between disulfidptosis and EMs based on bioinformatics analysis, machine learning, and animal experiments. Further investigation on the biological mechanism of disulfidptosis in EMs is anticipated to yield novel advancements for searching for potential diagnostic biomarkers and revolutionary therapeutic approaches in EMs.

Mechanosensing through talin 1 contributes to tissue mechanical homeostasis

It is widely believed that tissue mechanical properties, determined mainly by the extracellular matrix (ECM), are actively maintained. However, despite its broad importance to biology and medicine, tissue mechanical homeostasis is poorly understood. To explore this hypothesis, we developed mutations in the mechanosensitive protein talin1 that alter cellular sensing of ECM stiffness. Mutation of a novel mechanosensitive site between talin1 rod domain helix bundles 1 and 2 (R1 and R2) shifted cellular stiffness sensing curves, enabling cells to spread and exert tension on compliant substrates. Opening of the R1-R2 interface promotes binding of the ARP2/3 complex subunit ARPC5L, which mediates the altered stiffness sensing. Ascending aortas from mice bearing these mutations show increased compliance, less fibrillar collagen, and rupture at lower pressure. Together, these results demonstrate that cellular stiffness sensing regulates ECM mechanical properties. These data thus directly support the mechanical homeostasis hypothesis and identify a novel mechanosensitive interaction within talin that contributes to this mechanism.