Alpha-7 Nicotinic Receptor Signaling Pathway Participates in the Neurogenesis Induced by ChAT-Positive Neurons in the Subventricular Zone.

Choline acetyltransferase-positive (ChAT+) neurons within the subventricular zone (SVZ) have been shown to promote neurogenesis after stroke in mice by secreting acetylcholine (ACh); however, the mechanisms remain unclear. Receptors known to bind ACh include the nicotinic ACh receptors (nAChRs), which are present in the SVZ and have been shown to be important for cell proliferation, differentiation, and survival. In this study, we investigated the neurogenic role of the alpha-7 nAChR (α7 nAChR) in a mouse model of middle cerebral artery occlusion (MCAO) by using α7 nAChR inhibitor methyllycaconitine. Mice subjected to MCAO exhibited elevated expression of cytomembrane and nuclear fibroblast growth factor receptor 1 (FGFR1), as well as increased expression of PI3K, pAkt, doublecortin (DCX), polysialylated - neuronal cell adhesion molecule (PSA-NCAM), and mammalian achaete-scute homolog 1 (Mash1). MCAO mice also had more glial fibrillary acidic protein (GFAP)/5-bromo-2'-deoxyuridine (BrdU)-positive cells and DCX-positive cells in the SVZ than did the sham-operated group. Methyllycaconitine treatment increased cytomembrane FGFR1 expression and GFAP/BrdU-positive cells, upregulated the levels of phosphoinositide 3-kinase (PI3K) and phospho-Akt (pAkt), decreased nuclear FGFR1 expression, decreased the number of DCX-positive cells, and reduced the levels of DCX, PSA-NCAM, and Mash1 in the SVZ of MCAO mice compared with levels in vehicle-treated MCAO mice. MCAO mice treated with α7 nAChR agonist PNU-282987 exhibited the opposite effects. Our data show that α7 nAChR may decrease the proliferation of neural stem cells and promote differentiation of existing neural stem cells after stroke. These results identify a new mechanism of SVZ ChAT+ neuron-induced neurogenesis.

[Effects and mechanisms of Xiao-Ai-Ping injection on angiogenesis].

This study was designed to investigate the effect of Xiao-Ai-Ping injection on cancer angiogenesis. CCK8 assay and Brd U incorporation immunofluorescence assay were used to detect the effect of Xiao-Ai-Ping injection on HUVECs proliferation; wound healing assay and transwell assay were employed to test the effect of Xiao-Ai-Ping injection on HUVECs migration. The anti-angiogenic effect of Xiao-Ai-Ping injection was examined by tube formation assay, rat aortic ring assay and chicken chorioallantoic membrane(CAM) assay. ELISA assay was used to measure the secretion of vascular endothelial growth factor(VEGF); and the activation of vascular endothelial growth factor receptor 2(VEGFR2) protein and its downstream signaling pathways were examined by Western blot. Our data demonstrated that Xiao-Ai-Ping injection inhibited HUVECs proliferation in a time- and dose-dependent manner, and the IC(50) (mg·m L(-1)) values for 24, 48 and 72 h were 48.7 ± 7.14, 29.1 ±2.25 and 22.0 ± 4.53, individually. Xiao-Ai-Ping injection inhibited HUVECs DNA synthesis and migration. Xiao-Ai-Ping injection suppressed HUVECs tube formation, and reduced microvessel sprouting from rat aortic rings and vessel growth in CAMs. Furthermore, Xiao-Ai-Ping injection attenuated the secretion of VEGF, and inhibited the expression of p-VEGFR2 and phosphorylation of protein kinase B(p-AKT). We conclude that Xiao-Ai-Ping injection inhibits angiogenesis by down-regulation of VEGF signaling and AKT pathway.

Autophagy and cathepsin L are involved in the antinociceptive effect of DMBC in a mouse acetic acid-writhing model.

AIM: 2-(3',5'-Dimethoxybenzylidene) cyclopentanone (DMBC) is a novel synthetic compound with antinociceptive activities. The aim of this study was to investigate the roles of the autophagic-lysosomal pathway in the antinociceptive effect of DMBC in a mouse acetic acid-writhing model. METHODS: Mouse acetic acid-writhing test and hotplate test were used to assess the antinociceptive effects of DMBC, 3-MA (autophagy inhibitor) and Clik148 (cathepsin L inhibitor). The drugs were administered peripherally (ip) or centrally (icv). RESULTS: Peripheral administration of 3-MA (7.5-30 mg/kg) or Clik148 (10-80 mg/kg) produced potent antinociceptive effect in acetic acid-writhing test. Central administration of 3-MA or Clik148 (12.5-50 nmol/L) produced comparable antinociceptive effect in acetic acid-writhing test. Peripheral administration of DMBC (25-50 mg/kg) produced potent antinociceptive effects in both acetic acid-writhing and hotplate tests. Furthermore, the antinociceptive effect produced by peripheral administration of DMBC (50 mg/kg) in acetic acid-writhing test was antagonized by low doses of 3-MA (3.75 mg/kg) or Clik148 (20 mg/kg) peripherally administered, but was not affected by 3-MA or Clik148 (25 nmol/L) centrally administered. CONCLUSION: Activation of central autophagy and cathepsin L is involved in nociception in mice, whereas peripheral autophagy and cathepsin L contributes, at least in part, to the antinociceptive effect of DMBC in mice.