Myofibroblast transition from mesenchymal or epithelial precursors triggers loss of the primary cilium. In epithelial cells this requires contact injury and TGFβ and is mediated by Rac- and Smad3-dependent myosin phosphorylation. Thus the myofibroblast is a unique cilium-less cell with markedly reprogrammed ciliary signaling.

Background: Generation of myofibroblasts, the culprit of fibrosis, requires cytoskeleton remodeling and Nox4 (NADPH oxidase) expression. The link between these events is unknown. Results: Down-regulation/inhibition of the cytoskeleton-controlled transcriptional coactivators, myocardin-related transcription factor (MRTF), and TAZ/YAP abrogates Nox4 expression. Conclusion: MRTF and TAZ/YAP are essential for Nox4 expression. Significance: We show new mechanisms whereby the cytoskeleton regulates cellular redox state and fibrogenesis.

Induced pluripotent stem cells (iPSC) derived from healthy individuals are important controls for disease-modeling studies. Here we apply precision health to create a high-quality resource of control iPSCs. Footprint-free lines were reprogrammed from four volunteers of the Personal Genome Project Canada (PGPC). Multilineage-directed differentiation efficiently produced functional cortical neurons, cardiomyocytes and hepatocytes. Pilot users demonstrated versatility by generating kidney organoids, T lymphocytes, and sensory neurons. A frameshift knockout was introduced into MYBPC3 and these cardiomyocytes exhibited the expected hypertrophic phenotype. Whole-genome sequencing-based annotation of PGPC lines revealed on average 20 coding variants. Importantly, nearly all annotated PGPC and HipSci lines harbored at least one pre-existing or acquired variant with cardiac, neurological, or other disease associations. Overall, PGPC lines were efficiently differentiated by multiple users into cells from six tissues for disease modeling, and variant-preferred healthy control lines were identified for specific disease settings.

BACKGROUND AND PURPOSEDynasore has been used extensively as an inhibitor of clathrin-mediated endocytosis. While studying the role of endocytosis in LPS-induced signalling events, we discovered that dynasore itself induced activation of NF-κB, independently of its effects on endocytosis and without involving the Toll-like receptor 4 signalling pathways. The purpose of this study was to characterize this novel effect and to explore the underlying mechanism of action. EXPERIMENTAL APPROACHWe utilized gel electrophoresis, microscopy, gene knockdown and luciferase-based promoter activity to evaluate the effect of dynasore on cell signalling pathways and to delineate the mechanisms involved in its effects, KEY RESULTSDynasore activated the NF-κB and IFN-β pathways by activating mitochondrial antiviral signalling protein (MAVS). We showed that MAVS is activated by NOX/Rac and forms high molecular weight aggregates, similar to that observed in response to viral infection. We also demonstrated that dynasore-induced activation of JNK occurs downstream of MAVS and is required for activation of NF-κB and IFN-β. CONCLUSION AND IMPLICATIONSThese findings demonstrate a novel effect of dynasore on cell signalling. We describe a novel Rac1-, ROS-and MAVS-mediated signalling cascade through which dynasore dramatically activates NF-κB, mimicking the viral induction of this key inflammatory signalling pathway. Our results call attention to the need for a broader interpretation of results when dynasore is used in its traditional fashion as an inhibitor of clathrin-mediated endocytosis. These results suggest the intriguing possibility that dynasore or one of its analogues might be of value as an antiviral therapeutic strategy or vaccine adjuvant.Abbreviations CME, clathrin-mediated endocytosis; DRP1, dynamin-related protein 1; MAVS, mitochondrial anti-viral signalling; MFN, mitofusin; ROS, reactive oxygen species; SAPK, stress-activated PK (JNK2); TLR4, Toll-like receptor 4