MiR-199a-3p inhibition facilitates cardiomyocyte differentiation of embryonic stem cell through promotion of MEF2C.

MicroRNAs (miRNAs) is a small molecule (19-25 nucleotide) noncoding RNA that inhibits the expression of target messenger RNA (mRNA) at the posttranscriptional level as an endogenous regulator. There is an increasing evidence that miR-199a-3p has a significant effect on the development of multiple tumors. However, the specific roles of miR-199a-3p in myocardial differentiation of embryonic stem cell still need to be investigated. Method of the hanging drop was used to build the model of cardiomyocyte differentiation of stem cell and beating rate of embryoid bodies (EBs) was calculated. The levels of intracellular MEF2C, a-MHC, GATA4, Nkx2.5, and cTnT mRNA were measured by real-time quantitative polymerase chain reaction, while the expressions of miR-199a-3p were detected simultaneously. Protein levels of MEF2C, a-MHC, GATA4, Nkx2.5, and cTnT were quantified by western blot analysis. Immunoreactivities of MEF2C and cTnT were analyzed by immunofluorescence. The interaction between miR-199a-3p and its predicted target (3'-untranslated region of MEF2C mRNA) was verified by luciferase assay. MiR-199a-3p levels increased during cardiogenesis. MiR-199a-3p inhibitor increased the beating rate of EBs and promoted expressions of cardiac-specific markers (GATA4, Nkx2.5, cTnT, and a-MHC). Notably, miR-199a-3p inhibition brought upregulation of MEF2C, which is the target of miR-199a-3p that we predicted and verified experimentally. In addition, MEF2C siRNA decreased miR-199a-3p inhibitor promoted EBs beating and attenuated miR-199a-3p inhibitor-induced cTnT and MEF2C expressions. The results above showed that MEF2C was involved in the process of promoting the differentiation of stem cells into cardiac myocytes by miR-199a-3p inhibitors.

MiR-183-5p Alleviates Chronic Constriction Injury-Induced Neuropathic Pain Through Inhibition of TREK-1.

MicroRNAs have been implicated in nerve injury and neuropathic pain. In the previous study we had shown that miR-96 can attenuate neuropathic pain through inhibition of Nav1.3. In this study, we investigated the role of miR-183, a same cluster member of microRNA with miR-96, in neuropathic pain and its potential mechanisms. We found that the expression level of miR-183-5p in dorsal root ganglion was decreased with the development of neuropathic pain induced by chronic constriction sciatic nerve injury (CCI). By contrast, the TREK-1, a K+ channel, was increased. Further investigation identified that intrathecal injection of miR-183-5p mimic efficiently ameliorated neuropathic pain and inhibited the expression of TREK-1, a predicted target gene of miR-183-5p. Luciferase assays confirmed the binding of miR-183-5p and TREK-1. In addition, over-expression of TREK-1 blocked the roles of miR-183-5p in neuropathic pain. Our findings suggested that miR-183-5P participated in the regulation of CCI-induced neuropathic pain through inhibiting the expression of TREK-1.

Celecoxib reverts oxaliplatin-induced neuropathic pain through inhibiting PI3K/Akt2 pathway in the mouse dorsal root ganglion.

Oxaliplatin (OXA) is the common and extremely potent anti-advanced colorectal cancer chemotherapeutic. Accumulating evidence reveals that OXA evokes mechanical and cold hypersensitivity. However, the mechanism underlying these bothersome and dose-limiting adverse effects is poorly understood. It is well known that cyclooxygenase-2 (COX-2) as well as phosphoinositide 3-kinase (PI3K)/Akt signaling mediate the neuropathic pain. But it is still unclear whether COX-2 or PI3K/Akt signaling participates in the regulation of OXA-induced hypersensitivity, as well as the linkage between COX-2 and PI3K/Akt signaling in mediating OXA-induced hypersensitivity. In this paper, we investigated the anti-nociceptive effect of celecoxib, an inhibitor of COX-2, on the OXA-induced neuropathic pain. We found that OXA increased the expression of cyclooxygenase-2 (COX-2) and Akt2 in the lumbar 4-5 (L4-5) dorsal root ganglion (DRG). And the administration of celecoxib alleviates the OXA-induced hypersensitivity and suppresses the COX-2 and PI3K/Akt2 signaling. Our findings showed that COX-2 and PI3K/Akt2 signaling in DRG contributed to the OXA-induced neuropathic pain. In addition, celecoxib enhanced the OXA-induced mortality of the human colon cancer cell line HCT-116. Thus, celecoxib might play a dual role in colorectal cancer treatment: alleviating OXA-induced neuropathic pain and facilitating the anti-tumor effects of OXA through their synergistic role.

Intrathecal miR-96 inhibits Nav1.3 expression and alleviates neuropathic pain in rat following chronic construction injury.

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression post-transcriptionally by binding to their cognate target mRNAs. Emerging evidence suggests that miRNAs are critical regulators of neuronal functions. The expression pattern of miRNAs in the peripheral nervous system after peripheral nerve injury suggest that miRNAs may have important and yet unknown roles in the mechanisms of pain. Thus, we examined the role of miR-96 in neuropathic pain using a rat model of the condition chronic constriction sciatic nerve injury (CCI). We found that miR-96 alleviated neuropathic pain. The level of miR-96 was decreased within the ipsilateral dorsal root ganglion (DRG) after peripheral nerve injury but the Nav1.3 level was increased. Specifically, Intrathecal administration of miR-96 suppressed the expression of Nav1.3 induced by CCI. Further examination revealed that miR-96 inhibited the Nav1.3 mRNA expression in the embryonic DRG neurons in vitro. Our findings suggest that miR-96 participate in the regulation of neuropathic pain through inhibiting the expression of Nav1.3 in the DRG of CCI rats.