■人脐带间充质干细胞(hucMSC)衍生的小细胞外囊泡(sEV)是天然纳米载体,具有治疗肝纤维化的潜力,在纳米医学和再生医学领域具有广泛的应用。然而,由于天然hucMSC-sEV在体内的非特异性分布以及在全身递送后被单核巨噬细胞部分清除,因此其治疗效果目前有限.因此,通过开发能够克服这些限制的工程化hucMSC-sEV,可以提高治疗效果.
■为了提高hucMSC-sEV的抗肝纤维化疗效,我们基因工程hucMSC-sEV在亲本细胞中过表达抗纤维化基因骨形态发生蛋白7(BMP7)。这是使用慢病毒转染实现的,随后通过超速离心分离负载BMP7的hucMSC-sEV。首先,C57BL/6J小鼠通过每周两次腹膜内注射50%四氯化碳(CCL4)诱导肝纤维化,共8周。这些小鼠随后通过尾静脉注射用BMP7+sEV治疗,和BMP7+sEVs的抗肝纤维化作用是用小动物体内成像验证,免疫组织化学(IHC),组织免疫荧光,和酶联免疫吸附测定(ELISA)。最后,进行细胞功能研究以确认体内结果。
■肝脏成像和肝脏组织病理学证实,工程化的hucMSC-sEV可以到达小鼠的肝脏并在活化的肝星状细胞(aHSC)周围聚集,与空白或阴性对照转染的hucMSC-sEV相比,负载BMP7的hucMSC-sEV具有明显更强的抗肝纤维化作用。体外,负载BMP7的hucMSC-sEV促进aHSC的表型逆转并抑制其增殖以增强抗纤维化作用。
■这些工程化的BMP7负载hucMSC-sEV为肝纤维化的临床治疗提供了一种新颖且有前途的策略。
UNASSIGNED: Human umbilical cord mesenchymal stem cell (hucMSC)-derived small extracellular vesicles (
sEVs) are natural nanocarriers with promising potential in treating liver fibrosis and have widespread applications in the fields of nanomedicine and regenerative medicine. However, the therapeutic efficacy of natural hucMSC-
sEVs is currently limited owing to their non-specific distribution in vivo and partial removal by mononuclear macrophages following systemic delivery. Thus, the therapeutic efficacy can be improved through the development of engineered hucMSC-
sEVs capable to overcome these limitations.
UNASSIGNED: To improve the anti-liver fibrosis efficacy of hucMSC-sEVs, we genetically engineered hucMSC-
sEVs to overexpress the anti-fibrotic gene bone morphogenic protein 7 (BMP7) in parental cells. This was achieved using lentiviral transfection, following which BMP7-loaded hucMSC-sEVs were isolated through ultracentrifugation. First, the liver fibrosis was induced in C57BL/6J mice by intraperitoneal injection of 50% carbon tetrachloride (CCL4) twice a week for 8 weeks. These mice were subsequently treated with BMP7+sEVs via tail vein injection, and the anti-liver fibrosis effect of BMP7+sEVs was validated using small animal in vivo imaging, immunohistochemistry (IHC), tissue immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Finally, cell function studies were performed to confirm the in vivo results.
UNASSIGNED: Liver imaging and liver histopathology confirmed that the engineered hucMSC-sEVs could reach the liver of mice and aggregate around activated hepatic stellate cells (aHSCs) with a significantly stronger anti-liver fibrosis effect of BMP7-loaded hucMSC-sEVs compared to those of blank or negative control-transfected hucMSC-
sEVs. In vitro, BMP7-loaded hucMSC-sEVs promoted the phenotypic reversal of aHSCs and inhibited their proliferation to enhance the anti-fibrotic effects.
UNASSIGNED: These engineered BMP7-loaded hucMSC-sEVs offer a novel and promising strategy for the clinical treatment of liver fibrosis.