Objective:To evaluate the role and molecular mechanism of laminin β1(LAMB1)in cortical neurons in regulation of glutamate receptors.Methods:Recombinant lentivirus(LV-shLamb1)-mediated knockdown of LAMB1 expression in mouse primary cortical neurons was performed,followed by immunofluorescence staining and Western blot to detect changes in F-actin,glutamate receptor subtypes(AMPA receptors GluR1/GluR2,NMDA receptors NR1/NR2A),and ERK-related protein expression in cortical neurons.Results:LV-shLamb1 significantly inhibited LAMB1 expression in mouse cortical neurons.Concurrently,LV-shLamb1 markedly increased F-actin polymerization,as well as the expression of AMPA receptor subunits GluR1 and GluR2,and NMDA receptor subunits NR1 and NR2A.Further,Western blot detection showed that the phosphorylation level of ERK was significantly increased after LV-shLamb1 infec-tion.Conclusion:LAMB1 is expressed in cortical neurons.Suppression of LAMB1 expression in mouse cortical neu-rons activates the ERK pathway,which in turn promotes the polymerization of the cytoskeletal protein F-actin and the expression of glutamate receptors.This suggests that LAMB1 may regulate F-actin homeostasis and glutamate receptor levels through the ERK pathway,thereby playing a potentially important role in neuronal function.

Objective:To evaluate the role and molecular mechanism of laminin β1(LAMB1)in cortical neurons in regulation of glutamate receptors.Methods:Recombinant lentivirus(LV-shLamb1)-mediated knockdown of LAMB1 expression in mouse primary cortical neurons was performed,followed by immunofluorescence staining and Western blot to detect changes in F-actin,glutamate receptor subtypes(AMPA receptors GluR1/GluR2,NMDA receptors NR1/NR2A),and ERK-related protein expression in cortical neurons.Results:LV-shLamb1 significantly inhibited LAMB1 expression in mouse cortical neurons.Concurrently,LV-shLamb1 markedly increased F-actin polymerization,as well as the expression of AMPA receptor subunits GluR1 and GluR2,and NMDA receptor subunits NR1 and NR2A.Further,Western blot detection showed that the phosphorylation level of ERK was significantly increased after LV-shLamb1 infec-tion.Conclusion:LAMB1 is expressed in cortical neurons.Suppression of LAMB1 expression in mouse cortical neu-rons activates the ERK pathway,which in turn promotes the polymerization of the cytoskeletal protein F-actin and the expression of glutamate receptors.This suggests that LAMB1 may regulate F-actin homeostasis and glutamate receptor levels through the ERK pathway,thereby playing a potentially important role in neuronal function.

Objective:To analyze the effect of depressive state on Alzheimer's disease(AD)mice,3xTg-AD mice were stimulated with chronic social frustration stress(CSDS)and chronic mild unpredictable stress(CUMS),to estab-lish an early AD-induced depression mouse model,and to detect cognitive and behavioral changes,activation of micro-glia in the hippocampus and neuronal loss.Methods:Three-month-old mice were subjected to 8-day stress stimulation alternately,the depressive state of the mice was evaluated by behavior,the evaluation criteria were formulated,and the cognitive behavior was detected and analyzed,and the hippocampal brain tissue sections were stained with immunofluo-rescence to observe the deposition of β-amyloid(Aβ)and the aggregation of microtubule-associated protein(tau),mi-croglia activation and neuronal loss.Results:Depression-related behavioral results showed that the CSDS+CUMS group had depression-related phenotypes.Cognitive-behavioral testing showed that the new object recognition index of the mice in the CSDS+CUMS group was significantly reduced(P＜0.05),and the Morris water maze showed that the spatial memory ability of the CSDS+CUMS group was significantly reduced(P＜0.05),but there was no obvious fear memory loss in the CSDS+CUMS group in the conditioned fear experiment.The results of immunofluorescence staining showed that Aβ deposition appeared in the hippocampus at 4 months of age,the activated microglia increased(P＜0.001),and a certain degree of neuronal loss appeared in the CSDS+CUMS group(P＜0.001);At 8 months of age,the CSDS+CUMS group showed tau protein aggregation early.Conclusion:We established a model of AD-induced de-pression in AD mice,in which 3xTg-AD mice experienced early decline in learning memory and increased AD-related pathological deposition of neurons in the hippocampus,accompanied by microglial activation and neuronal loss.

AIM To study the inhibitory effect of the cytotoxin (CTX) from guangxi cobra venom on human nasopharyngeal cancer cell (CNE) and other tumons cells. METHODS The cytotoxin was isolated and purified from Guangxi cobra venom by successive chromatography on Sephadex G-50 and CM Sepharose CL-6B columns. Its cytotoxic effects and does-effect relationship on human tumors cell lines were examined by MTT assay. RESULTS The inhibitory effects of CTX CM-5 on CNE, human ovarian carcinoma cell (Ho8990), uterus cervical carcinoma cell (HELA) and lymphoma (YAC) cell lines showed a definite does-effect relationship. The IC 50 (48 h in cubation) was 1.84, 2.59, 1.84 and 0.75 mg?L -1 respctively. The inhibitory effects of CTX CM-5 on CNE increased with time. The IC 50 (3 h and 24 h cubation) was 4.78 and 1.04 mg?L -1 respctively. CONCLUSION CTX from Guangxi cobra venom exhibites strong suppressive effect on cultured tumor cells line in vitro.