Exosomes secreted from miRNA-29b-modified mesenchymal stem cells repaired spinal cord injury in rats

Exosomes, a kind of extracellular vesicle, are promising therapeutic agents for spinal cord injury (SCI). This article aimed to investigate effects of exosomes secreted from miRNA-29b-modified bone marrow mesenchymal stem cells (BMSCs) on SCI. Exosomes were extracted from BMSCs transfected with miRNA-29b or negative control (miR NC). SCI rats were injected intravenously with exosomes (control exosomes, miRNA-29b exosomes) and BMSCs (miR NC, miRNA-29b) through the tail vein. The expression of miRNA-29b in spinal cord tissues of SCI rats was detected by qRT-PCR. The hind limb motor function was evaluated by Basso Beattie Bresnahan (BBB) score. The histopathological damage and neuronal regeneration in spinal cord tissues was observed by HE staining and immunohistochemistry, respectively. The injection of miRNA-29b exosomes and miRNA-29b BMSCs both significantly increased the expression of miRNA-29b in spinal cord tissues of SCI rats (P<0.05). Compared with SCI rats, rats in the miRNA-29b exosomes and the miRNA-29b groups exhibited improved SCI, including increased BBB score, NF200 and GAP-43 positive neurons, as well as decreased contractile nerve cell numbers and GFAP positive neurons (all P<0.05). The relieving degree of SCI was significantly higher in the miRNA-29b exosomes group than in the miRNA-29b BMSCs group (P<0.05). Exosomes secreted from miRNA-29b-modified BMSCs were effective in the repair of SCI in rats.

Construction of miRNA-29b1 knockout mice based on CRISPR/Cas9 technology / 中国比较医学杂志

Objective To construct miRNA-29b1 gene knockout mice based on CRISPR/Cas9 technology. Methods To design and synthesize sgRNA according to the miRNA-29b1 sequence in Genbank .sgRNA and Cas9 were transcribed to RNA in vitro, these RNA were then microinjected into zygotes of C 57BL/6 mice.After mouse birth, the genome DNA was extracted and sequenced to identify its genotype; meanwhile , real-time PCR was used to assay the expression of miRNA-29b1 in the heart, liver, spleen, lung and kidney of mutated mice .Result A 20 bp sgRNA targeted on miRNA-29b1 was synthesized and transcribed to RNA with Cas 9.After microinjection, miRNA-29b1 gene-mutated mice were obtained.The sequencing results showed that there were two types of genotype for the mutated mice , one was 10 bp deletion, and another was 23 bp deletion accompanied with a 3 bp insertion.Compared with the wild-type mice, the expression of miRNA-29b1 in the heart, liver, spleen, lung and kidney was reduced significantly .Conclusions miRNA-29b1 gene knockout mice are constructed successfully by using CRISPR /Cas9 technology.

Effects of microRNA-29b on invasion and proliferation of human high peritoneal metastatic gastric cancer cells / 中华消化杂志

Objective To investigate the expression of microRNA-29b (miR-29b) in gastric cancer cell line GC9811 and high peritoneal metastatic gastric cancer cell line GC9811-P and its effect on invasion,proliferation and apoptosis.Methods The relative quantitative expression of miR-29b was detected by quantitative realtime polymerase chain reaction(qRT PCR).GC9811 cells were divided into three groups,miRNA down-regulated and transfected with lentiviruses LV-miR-29b inhibitor group,negative control group with negative transfection,and untransfected blank control group.GC9811-P cells were divided into three groups,miR-29b up regulated and transfected with lentiviruses LV miR 29b group,negative control with negative transfection group,and untransfected blank control group.The cell invasion ability was detected with Transwell assay,the cell proliferation ability was measured by methyl-thiazolyl tetrazolium (MTT) test,the colony forming ability was determined by plate colony formation assay,and the apoptosis was tested by flow cytometry.The expressions of miR 29b and secreted protein,acidic and rich in cystenie (SPARC) in gastric cell line GC9811-P,GC9811,MKN28M,MKN28NM and normal gastric cell line GES were determined by qRT-PCR,and the correlation was analyzed.Two independent samples t test or SNK-q test was performed for mean comparison between two groups,and one way analysis of variance was used for mean comparison among three groups.Results The relative quantitative expression of miR-29b inGC9811-P (0.21±-0.04) was significantly lower than that of GC9811 (1.00±0.03,t 28.140,P＜ 0.01).After GC9811 cells transfected with lentiviruses LV-miR-29b inhibitor,the expression of miR-29b (0.21±0.04) was significantly lower than that of control group (0.89±0.07) and blank control group (1.00±0.04,q 12.76,14.73,both P＜0.01).Compared with negative group,the transmembrane cell number and the clonality of miRNA up-regulated group raised(274.33± 9.03 vs 110.67 ± 13.69,t=9.981,P＜0.01;131.33±4.91 vs69.67±2.33,t 11.340,P＜0.01),and the results of MTT test also shows the proliferation was increased.After GC9811-P cells transfected with LV-miR-29b,the expression of miR 29b (4.08±0.20) was significantly higher than that of negative control group (1.15±0.05) and blank control group (1.00±0.10,q=21.73,22.81,both P＜0.01).Compared with negative group,the transmembrane cell number and the clonality of miRNA up regulated group reduced (51.33±5.55 vs 104.00±6.24,t 6.305,P＜0.01; 48.00±5.51 vs 113.33±5.17,t 11.340,P＜0.01),and the results of MTT test also shows the proliferation was weakened.Apoptosis assays demonstrated miR-29b promoted apoptosis; however,the difference was not statistically significant.The expression of miR-29b was negatively correlated with SPARC mRNA in gastric cancer cells (r=-0.97,P=0.03).Conclusions The low expression of miR-29b in high peritoneal metastatic gastric cancer cell inhibited the ability of invasion and proliferation.MiR-29b might be a new target of inhibiting peritoneal metastasis in gastric cancer.