Generation of Mlk3 KO mice by CRISPR/Cas9 and its effect on blood pressure / 生物工程学报

To explore the effect of Mlk3 (mixed lineage kinase 3) deficiency on blood pressure, Mlk3 gene knockout (Mlk3KO) mice were generated. Activities of sgRNAs targeted Mlk3 gene were evaluated by T7 endonuclease I (T7E1) assay. CRISPR/Cas9 mRNA and sgRNA were obtained by in vitro transcription, microinjected into zygote, followed by transferring into a foster mother. Genotyping and DNA sequencing confirmed the deletion of Mlk3 gene. Real- time PCR (RT-PCR), Western blotting or immunofluorescence analysis showed that Mlk3KO mice had an undetectable expression of Mlk3 mRNA or Mlk3 protein. Mlk3KO mice exhibited an elevated systolic blood pressure compared with wild-type mice as measured by tail-cuff system. Immunohistochemistry and Western blotting analysis showed that the phosphorylation of MLC (myosin light chain) was significantly increased in aorta isolated from Mlk3KO mice. Together, Mlk3KO mice was successfully generated by CRISPR/Cas9 system. MLK3 functions in maintaining blood pressure homeostasis by regulating MLC phosphorylation. This study provides an animal model for exploring the mechanism by which Mlk3 protects against the development of hypertension and hypertensive cardiovascular remodeling.

Effects of DL-3-n-Butylphthalide on Proliferation and Apoptosis of 1-Methyl-4-Phenylpyridinium-induced SH-SY5Y Cells via Mixed Lineage Kinase 3 Signaling Pathway / 中国康复理论与实践

Objective To investigate the effects of DL-3-n-Butylphthalide(NBP)on proliferation and apoptosis of 1-methyl-4-phenyl-pyridinium (MPP +)-induced SH-SY5Y cells, and mechanisms via mixed lineage kinase 3 (MLK3) signaling pathway. Methods The SH-SY5Y cells were divided into control group,MPP+group,NBP group and URMC-099 group,that cultured normally,with 1 mmol/L MPP+for 24 hours,with 10μmol/L NBP for 3 hours and then with MPP+for 24 hours,and with 200 nmol/L MLK3 inhibitor URMC-099 for 3 hours and then with MPP+for 24 hours,respectively.The morphology of SH-SY5Y cells was observed under inverted phase contrast mi-croscope and the survival rate was measured with 3-(4,5-Cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays.The apoptosis was quantified under flow cytometry with Annexin V/PI fluorescence staining,and the nuclear morphology was observed with Hoechst 33342 staining.The expression of phosphorylated protein of MLK3(p-MLK3),c-Jun N-terminal kinase(p-JNK),extra cellular regulated protein ki-nases(p-ERK1/2)were detected with Western blotting.Results Compared with the control group,the survival rate reduced and apoptosis in-creased in MPP+group(P<0.05),with the increase of p-MLK3 and p-JNK and decrease of p-ERK1/2 d(P<0.05).Compared with MPP+group,the survival rate increased and apoptosis reduced in both NBP and URMC-099 groups(P<0.05),with the decrease of p-MLK3 and p-JNK and increase of p-ERK1/2(P<0.05).Conclusion NBP can decrease the apoptosis and promote the proliferation of SH-SY5Y cells in-duced by MPP+,which may be associated with inhibiting MLK3 signaling pathway,and regulating the downstream p-JNK and p-ERK1/2.