Experimental cell research
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After CNS injury, astrocytes and mesenchymal cells attempt to restore the disrupted glia limitans by secreting proteoglycans and extracellular matrix proteins (ECMs), forming the so-called glial scar. Although the glial scar is important in sealing the lesion, it is also a physical and functional barrier that prevents axonal regeneration. The synthesis of secretory proteins in the RER is under the control of the initiation factor of translation eIF2α. ⋯ Besides, Salubrinal also reduced the transcription of proteoglycans and other profibrotic proteins, suggesting that it induced the degradation of non-translated mRNA. In a model in vitro of the glial scar, cortical neurons grown on cocultures of astrocytes and fibroblasts with TGFβ treated with Salubrinal, showed increased neurite outgrowth compared to untreated cells. Our results suggest that Salubrinal may be considered of therapeutic value facilitating axonal regeneration, by reducing overproduction and secretion of proteoglycans and profibrotic protein inhibitors of axonal growth.
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Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Interferon-alpha (IFN-α) has recently been recognized to harbor therapeutic potential in the prevention and treatment of HCC, but it remains controversial as to whether IFN-α exerts direct cytotoxicity against HCC. Cyclooxygenase-2 (COX-2) is overexpressed in HCC and is considered to play a role in hepatocarcinogenesis. ⋯ The molecular mechanisms of HCC cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. Interferon-α and the COX-2 inhibitor celecoxib synergistically increased TRAIL-induced apoptosis in hepatocellular carcinoma. These data suggest that IFN-α and celecoxib may offer a novel role with important implications in designing new therapeutics for TRAIL-resistant tumors.
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Adipose derived stem cells (ADSC) can be differentiated into Schwann cell-like cells which enhance nerve function and regeneration. However, the signalling mechanisms underlying the neurotrophic potential of ADSC remain largely unknown. In this study, we hypothesised that ADSC, upon stimulation with a combination of growth factors, could rapidly produce brain derived neurotrophic factor (BDNF) with a similar molecular mechanism to that functioning in the nervous system. ⋯ Stimulation also activated the BDNF expression gating transcription factor, cAMP responsive element binding (CREB) protein. However, blocking phosphorylation of CREB with the protein kinase A small molecule inhibitor H89 did not suppress secretion of BDNF protein. These results suggest rapid BDNF production in ADSC is mediated through multiple compensatory pathways independent of, or in addition to, the CREB neuronal activation cascade.
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Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by proteinaceous pulmonary edema and severe arterial hypoxemia with a mortality of approximately 40%. Stimulation of epithelial sodium channel (ENaC) promotes Na(+) transport, a rate-limiting step for pulmonary edema reabsorption. Insulin is known to participate in the ion transport; however, its role in pulmonary edema clearance and the regulatory mechanism involved have not been fully elucidated. ⋯ In addition, an immunoprecipitation study demonstrated that SGK1(Ser422) phosphorylation, the key step for complete SGK1 activation by insulin, was conducted through PI3K/mTORC2 pathway. Finally, we testified the role of mTORC2 in vivo by demonstrating that PP242 prevented insulin-stimulated SGK1 activation and ENaC increase during ALI. The data revealed that during ALI, insulin stimulates alveolar fluid clearance by upregulating the expression of α-, β-, and γ-ENaC at the cell surface, which was, at least, partially through activating mTROC2/SGK1 signaling pathway.