ABSTRACT
OBJECTIVE To investigate the effect of psychedelics on innate fear behavior of mice in Looming model(LM)and its neurobiological mechanism.METH-ODS ① Adult male C57BL/6J mice were randomly divid-ed into saline group,DOM group,psilocybin group and mescaline group.The drugs of the corresponding groups were given ip injecction 5 min in advance and LM were used to test the effect of them on freezing time in shelter of mice.② The mice were performing ip given DOM or psilocybin following 5-HT2A receptor antagonist M100907 ip 30 min later involved looming experiments.③Quan-tified the expression of EGR1 protein in mouse brains by immunofluorescence staining,then use ibotenic acid(IBO)damaged the mouse brain regions based on the result above and performed looming experiments.④ Specifically activate or inhibit CaMK Ⅱ,PV,VIP and SOM neurons of mice in saline or psilocybin groups respec-tively by chemical genetic methods and followed looming experiments.RESULTS ① In LM,the freezing time in shelter of mice in DOM,psilocybin and mescaline groups was significantly shorter compared to the saline group(P<0.05),and the dose-effect curves of above psyche-delics were U-shaped.② Compared with the vehicle + psilocybin/DOM groups,the freezing time in shelter of mice in M100907 + psilocybin/DOM groups was signifi-cantly prolonged(P<0.05),and there was no significant difference between the vehicle + saline group and the M100907 + psilocybin/DOM groups.③ Psilocybin signifi-cantly increased the expression of EGR1 protein in prelim-bic cortex(PrL)compared with saline,and the damage of PrL could effectively antagonized the effect of psilocybin shortening the freezing time in LM.④ Chemicalgenetic specific inhibition of CaMK Ⅱ,PV or VIP neurons in PrL could effectively antagonize the effect of psilocybin in LM,while chemicalgenetic specific activation of CaMK Ⅱneurons could significantly shorten the freezing time of saline-treated mice.CONCLUSION Psychedelics have capability to waken the innate fear behavior like freez-ing of mice in LM,and this effect is mediated by 5-HT2A receptor and CaMK Ⅱneuron in PrL.
ABSTRACT
Cas9 is a RNA-guided double stranded DNA nuclease that participates in the CRISPR/Cas9 system. Wide-type Cas9 directly silences the expression of target gene by gene splicing. The engineered dCas9 protein with the mutation at D10A and H840A lacks the Cas9' s endonuclease function but keeps its DNA binding activity. dCas9 can activate special genes by fusing with transcription activator. Meanwhile,it can inhibit the gene transcription by directly binding to the target gene and stop gene transcrip?tion. Combination of light sensitive structures and CRISPR can produce light-inducible CRISPR/Cas9 system for control of gene expres?sion. This system is able to activate or inhibit gene expression via the use of controlling blue light(470 nm). In this review,we mainly discuss the development of the light inducible CRISPR/Cas9 system as well as its application in the control of gene expression.
ABSTRACT
OBJECTIVE To investigate the effect of clopidogrel(Clog),a platelet aggregation inhibitor,on the development of colitis-associated colon cancer(CAC)and its possible mechanism. METHODS To establish a CAC model,male BALB/c mice were treated with single azoxymethane(AOM) 10 mg · kg-1 by ip. One week later,the mice drank 2.5% dextran sulfate sodium(DSS)for one week and water for two weeks,which lasted three cycles. From the first day mice received 2.5%DSS water, Clog 12.5,25.0 and 50.0 mg · kg-1 was ig administered once a day. Body mass,clinical symptoms,the number of colon tumor and tumor size in colon tissue were recorded. Hyperplasia of tumors was analyzed by HE staining. In the early inflammatory phase of the CAC model,the length of colons was measured, histological structure and epithelium cell proliferation of colon tissues were evaluated by HE staining and Ki67 staining,respectively. In the tumorigenesis and progression phase of the CAC model,epithe?lium cell proliferation of colon tissues was evaluated by Ki67 staining. The mRNA expression of tumor necrosis factor-α(TNF-α)was detected by real-time quantitative PCR. The expression of chemokine(C-X-C motif)ligand 2(CXCL2)and its receptor 2(CXCR2)in colon tissues was detected by PCR and immu?nohistochemistry. RESULTS Compared with model group,clinical symptoms of mice in Clog 12.5 mg · kg-1 group were alleviated,the size of colon tumors was decreased(P<0.05),and hyperplasia of tumors was reduced(P<0.05). During the inflammatory phase,the clinical symptoms of mice in Clog 12.5 mg·kg-1 group were significantly alleviated(P<0.05),the decrease of body mass was reduced(P<0.01),the colon shrinkage was ameliorated(P<0.01),the inflammatory injury and epithelium cell proliferation in colon tissues were reduced(P<0.05). During the tumorigenesis and progression phase,epithelium cell prolif?eration in colon tissues in Clog 12.5 mg·kg-1 group was reduced(P<0.01),and the mRNA and protein expression of TNF-α,CXCL2 and CXCR2 of colon tissues was decreased(P<0.05). CONCLUSION Clog can alleviate inflammation during the CAC early inflammatory phase and inhibit the formation of CAC. The antitumor effect of Clog may be related to the decrease in expression of CXCL2 and CXCR2.
ABSTRACT
Antitumor effects of erythromycin and the related mechanism were investigated in the present study. Neuroblastoma cells (SH-SY5Y) were exposed to erythromycin at different concentrations for different durations. Cell proliferation was measured by cell counting, and cell viability was examined by MTT assay. Cell cycle phase distribution and the cytosolic calcium level were detected by flow cytometry. Mitochondrial membrane potential was measured by the JC-1 probe staining and fluorescent microscopy. The expression of an oncogene (c-Myc) and a tumor suppressor [p21 (WAF1/Cip1)] proteins was analyzed by using Western blotting. Erythromycin could inhibit the proliferation of SH-SY5Y cells in a concentration- and time-dependent manner. The cell cycle was arrested at S phase. Mitochondrial membrane potential collapsed and the cytosolic calcium was overloaded in SH-SY5Y cells when treated with erythromycin. The expression of c-Myc protein was down-regulated, while that of p21 (WAF1/Cip1) protein was up-regulated. It was concluded that erythromycin could restrain the proliferation of SH-SY5Y cells. The antitumor mechanism of erythromycin might involve regulating the expression of c-Myc and p21 (WAF1/Cip1) proteins.