Gp350-anchored extracellular vesicles: promising vehicles for delivering therapeutic drugs of B cell malignancies.

Although chimeric antigen receptor-modified (CAR) T cell therapy has been successfully applied in the treatment of acute B lymphocytic leukemia, its effect on Burkitt lymphoma (BL) and chronic B lymphocytic leukemia (B-CLL) is unsatisfactory. Moreover, fatal side effects greatly impede CAR T cell application. Extracellular vesicles (EVs) are excellent carriers of therapeutic agents. Nevertheless, EVs mainly accumulate in the liver when administered without modification. As an envelope glycoprotein of Epstein-Barr viruses, gp350 can efficiently bind CD21 on B cells. Here, gp350 was directly anchored onto red blood cell EVs (RBC-EVs) via its transmembrane region combined with low-voltage electroporation. The results showed that gp350 could anchor to RBC-EVs with high efficiency and that the resulting gp350-anchored RBC-EVs (RBC-EVs/gp350Etp) exhibited increased targeting to CD21+ BL and B-CLL relative to RBC-EVs. After the loading of doxorubicin or fludarabine, RBC-EVs/gp350Etp had powerful cytotoxicity and therapeutic efficacy on CD21+ BL or B-CLL, respectively. Moreover, RBC-EVs/gp350Etp loaded with a drug did not exhibit any apparent systemic toxicity and specifically induced the apoptosis of tumor B cells but not normal B cells. Therefore, our findings indicate that drug-loaded RBC-EVs/gp350Etp may be adopted in the treatment of CD21+ B cell malignancies.

Emodin promotes fibroblast apoptosis and prevents epidural fibrosis through PERK pathway in rats.

BACKGROUND: Laminectomy is usually classed as a common orthopedic surgery, but postoperative epidural fibrosis often leads to less-than-desirable clinical outcomes. As demonstrated by prior studies, emodin (EMO) exerts an anti-fibrotic effect. Here, we carried out investigation into the inhibitory effect created by EMO application on epidural fibrosis after laminectomy in rats. METHODS: The paper conducts a series of experiment. In vitro, we observed the effect of EMO on fibroblasts by Cell Counting Kit-8 (CCK-8) assay. Apoptosis of fibroblasts induced by EMO was detected by western blot, TUNEL assay, and flow cytometry. The results revealed that EMO was capable of inducing fibroblast apoptosis, and the proteins of PERK pathway also changed accordingly. In vivo, the effect of EMO on epidural fibrosis in 12 male Sprague-Dawley rats was observed by histological staining. RESULTS: CCK-8 assay indicated that EMO was effective in reducing fibroblast viability in a time- and a dose-dependent manner. TUNEL assay and flow cytometry analysis have demonstrated that the apoptotic rate of fibroblasts increased as the EMO concentration rose. Western blot analysis proved that EMO promoted the relative expression of p-perk and p-eIF2α and that the expression of its downstream proteins CHOP and GRP78 was also enhanced. The expression of apoptotic protein Bax and cleaved PARP was upregulated, whereas the expression of anti-apoptotic protein Bcl-2 was downregulated. In addition, histological and immunohistochemical analysis demonstrated that EMO functioned to inhibit epidural fibrosis and increase GRP78 expression in fibrous tissue by promoting apoptosis of fibroblasts. CONCLUSIONS: EMO could have inhibitory effect on epidural fibrosis in a concentration-dependent manner. The potential mechanism might be through PERK signaling pathway to promote fibroblast apoptosis. It has a possibility to be taken as a novel method for the treatment of epidural fibrosis.

Artesunate protects against surgery-induced knee arthrofibrosis by activating Beclin-1-mediated autophagy via inhibition of mTOR signaling.

Intraarticular fibrosis following knee surgery is a troublesome complication and remains a challenging problem for clinicians. Artesunate (ART), a classical anti-malarial drug extracted from the Chinese medicinal herb Artemisia annua L, has been associated with some fibrosis-related diseases. However, its effect and underlying mechanism on knee arthrofibrosis are still obscure. In the present study, we found that ART induced cellular autophagy flux and inhibited cell proliferation in fibroblasts. Intriguingly, genetic depletion of Beclin-1 abolished ART-triggered cellular autophagy and further attenuated the inhibitory effect of ART on fibroblasts proliferation. Moreover, at molecular level, our results demonstrated that ART-induced autophagy activation was associated with the inhibition of mTOR signaling through PI3K/AKT/mTOR pathway and AMPK/mTOR pathway. In vivo, ART treatment triggered autophagy activation and alleviated the severity of surgery-induced knee arthrofibrosis. Taken together, we concluded that ART exhibited anti-proliferation efficacy in fibroblasts and alleviated the severity of knee arthrofibrosis in rabbits by inducing Beclin-1-mediated autophagy via inhibition of mTOR signaling. These findings indicated that ART might be a potential therapeutic agent for preventing the progression of surgery-induced intraarticular fibrosis of knee.