👤 Alexis Paquin

Endothelial-to-mesenchymal transition (EndMT) is a biological process that converts endothelial cells to mesenchymal cells with increased proliferative and migrative abilities. EndMT has been implicated in the development of pulmonary vascular remodeling in pulmonary arterial hypertension (PAH), a fatal and progressive lung vascular disease. Transforming growth factor β Show less

Endothelial-to-mesenchymal transition (EndMT) is a biological process that converts endothelial cells to mesenchymal cells with increased proliferative and migrative abilities. EndMT has been implicated in the development of pulmonary vascular remodeling in pulmonary arterial hypertension (PAH), a fatal and progressive lung vascular disease. Transforming growth factor β EndMT has been reported to contribute to the pathogenesis of PH. In this study we aimed to determine the role of Ca Show less

Glioblastoma (GBM) is a highly angiogenic malignancy of the central nervous system that resists standard antiangiogenic therapy, in part because of an alternative process to angiogenesis termed vasculogenic mimicry. Intricately linked to GBM, dysregulation of the Hippo signaling pathway leads to overexpression of YAP/TEAD and several downstream effectors involved in therapy resistance. Little is known about whether vasculogenic mimicry and the Hippo pathway intersect in the GBM chemoresistance phenotype. This study seeks to investigate the expression patterns of Hippo pathway regulators within clinically annotated GBM samples, examining their involvement in vitro regarding vasculogenic mimicry. In addition, it aims to assess the potential for pharmacological targeting of this pathway. In-silico analysis of the Hippo signaling members YAP1 , TEAD1 , AXL , NF2 , CTGF , and CYR61 transcript levels in low-grade GBM and GBM tumor tissues was done by Gene Expression Profiling Interactive Analysis. Gene expression was analyzed by real-time quantitative PCR from human U87, U118, U138, and U251 brain cancer cell lines and in clinically annotated brain tumor cDNA arrays. Transient gene silencing was performed with specific small interfering RNA. Vasculogenic mimicry was assessed using a Cultrex matrix, and three-dimensional capillary-like structures were analyzed with Wimasis. CYR61 and CTGF transcript levels were elevated in GBM tissues and were further induced when in-vitro vasculogenic mimicry was assessed. Silencing of CYR61 and CTGF , or treatment with a small-molecule TEAD inhibitor LM98 derived from flufenamic acid, inhibited vasculogenic mimicry. Silencing of SNAI1 and FOXC2 also altered vasculogenic mimicry and reduced CYR61 / CTGF levels. Pharmacological targeting of the Hippo pathway inhibits in-vitro vasculogenic mimicry. Unraveling the connections between the Hippo pathway and vasculogenic mimicry may pave the way for innovative therapeutic strategies. Show less

Increasing evidence suggests that deficits in adult stem cell maintenance cause aberrant tissue repair and premature aging [1]. While the mechanisms regulating stem cell longevity are largely unknown, recent studies have implicated p53 and its family member p63. Both proteins regulate organismal aging [2-4] as well as survival and self-renewal of tissue stem cells [5-9]. Intriguingly, haploinsufficiency for a third family member, p73, causes age-related neurodegeneration [10]. While this phenotype is at least partially due to loss of the ΔNp73 isoform, a potent neuronal prosurvival protein [11-16], a recent study showed that mice lacking the other p73 isoform, TAp73, have perturbations in the hippocampal dentate gyrus [17], a major neurogenic site in the adult brain. These findings, and the link between the p53 family, stem cells, and aging, suggest that TAp73 might play a previously unanticipated role in maintenance of neural stem cells. Here, we have tested this hypothesis and show that TAp73 ensures normal adult neurogenesis by promoting the long-term maintenance of neural stem cells. Moreover, we show that TAp73 does this by transcriptionally regulating the bHLH Hey2, which itself promotes neural precursor maintenance by preventing premature differentiation. Show less