Targeted Dual Small Interfering Ribonucleic Acid Delivery via Non-Viral Polymeric Vectors for Pulmonary Fibrosis Therapy.

Inhibiting the myofibroblast differentiation of lung-resident mesenchymal stem cells (LR-MSCs) is a promising yet challenging approach for pulmonary fibrosis (PF) therapy. Here, micelles formed by a graft copolymer of multiple PEGs modified branched polyethylenimine are used for delivering runt-related transcription factor-1 (RUNX1) small interfering RNA (siRNA) (siRUNX1) to the lung, aiming to inhibit the myofibroblast differentiation of LR-MSCs. LR-MSC targeting is achieved by functionalizing the micelle surface with an anti-stem-cell antigen-1 antibody fragment (Fab'). Consequently, therapeutic benefits are obtained by successful suppression of myofibroblast differentiation of LR-MSCs in bleomycin-induced PF model mice treated with siRUNX1-loaded micelles. Furthermore, an excellent synergistic effect of PF therapy is achieved for this micelle system loaded siRUNX1 and glioma-associated oncogene homolog-1 (Gli1) small interfering RNA (siGli1), a traditional anti-PF siRNA of glioma-associated oncogene homolog-1. Hence, this work not only provides RUNX1 as a novel PF therapeutic target, but also as a promising dual siRNA-loaded nanocarrier system for the therapy of PF.

Co-delivery of siPTPN13 and siNOX4 via (myo)fibroblast-targeting polymeric micelles for idiopathic pulmonary fibrosis therapy.

Rationale: (Myo)fibroblasts are the ultimate effector cells responsible for the production of collagen within alveolar structures, a core phenomenon in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Although (myo)fibroblast-targeted therapy holds great promise for suppressing the progression of IPF, its development is hindered by the limited drug delivery efficacy to (myo)fibroblasts and the vicious circle of (myo)fibroblast activation and evasion of apoptosis. Methods: Here, a dual small interfering RNA (siRNA)-loaded delivery system of polymeric micelles is developed to suppress the development of pulmonary fibrosis via a two-arm mechanism. The micelles are endowed with (myo)fibroblast-targeting ability by modifying the Fab' fragment of the anti-platelet-derived growth factor receptor-α (PDGFRα) antibody onto their surface. Two different sequences of siRNA targeting protein tyrosine phosphatase-N13 (PTPN13, a promoter of the resistance of (myo)fibroblasts to Fas-induced apoptosis) and NADPH oxidase-4 (NOX4, a key regulator for (myo)fibroblast differentiation and activation) are loaded into micelles to inhibit the formation of fibroblastic foci. Results: We demonstrate that Fab'-conjugated dual siRNA-micelles exhibit higher affinity to (myo)fibroblasts in fibrotic lung tissue. This Fab'-conjugated dual siRNA-micelle can achieve remarkable antifibrotic effects on the formation of fibroblastic foci by, on the one hand, suppressing (myo)fibroblast activation via siRNA-induced knockdown of NOX4 and, on the other hand, sensitizing (myo)fibroblasts to Fas-induced apoptosis by siRNA-mediated PTPN13 silencing. In addition, this (myo)fibroblast-targeting siRNA-loaded micelle did not induce significant damage to major organs, and no histopathological abnormities were observed in murine models. Conclusion: The (myo)fibroblast-targeting dual siRNA-loaded micelles offer a potential strategy with promising prospects in molecular-targeted fibrosis therapy.

Protective effect of ginsenoside Rg1 on LPS-induced apoptosis of lung epithelial cells.

Sepsis-induced acute lung injury (ALI) is a life-threatening medical condition with high mortality and morbidity in the critical care units. Though, it was commonly accepted that inflammation and apoptosis of lung epithelial cells played an essential role in the pathogenesis of ALI, the underlying mechanism remain unknown. In our study, we found that LPS-induced cell apoptosis could be counteracted by elevated cell autophagy. In LPS-treated MLE-12 cells, suppression of autophagy via 3-MA could aggravate LPS-induced apoptosis, while activation of autophagy via Rapamycin could effectively impair the apoptosis of MLE-12 cells induced by LPS. In order to further discover the molecular regulation mechanism between apoptosis and autophagy in LPS-treated MLE-12 cells, we demonstrated that autophagy could induced the expression of Nrf2, followed with the decrease of p-p65. Targeted inhibition of Nrf2 could induce enlarged cell apoptosis via increasing the level of p-p65. In addition, we demonstrated that ginsenoside Rg1 protected MLE-12 cells from LPS-induced apoptosis via augmenting autophagy and inducing the expression of Nrf2. Our data implicates that activation of autophagy and Nrf2 by ginsenoside Rg1 may provide a preventive and therapeutic strategy for ALI.

Long non-coding RNA Hsp4 alleviates lipopolysaccharide-induced apoptosis of lung epithelial cells via miRNA-466m-3p/DNAjb6 axis.

Acute lung injury (ALI), as a life-threatening syndrome, is mainly characterized with diffuse alveolar injury, excessive pulmonary inflammation, edema and apoptosis of lung epithelial cells. This study investigated the effects of LncRNA Hsp4 (Hsp4, ENSMUST00000175718) on lipopolysaccharide (LPS)-induced apoptosis of MLE-12 cells. In our research, we found that LPS treatment remarkably induced apoptosis of MLE-12 cells and decreased the expression of Hsp4. Overexpression of Hsp4 significantly reversed LPS-induced cell apoptosis through inhibiting mTOR signaling, while suppression of Hsp4 presented opposite effects. Further results showed that Hsp4 positively regulated the expression of miR-466m-3p. Knockdown of miR-466m-3p reversed LPS-induced cell apoptosis via increasing the levels of DNAjb6 which was confirmed to be the target gene of miR-466m-3p. This finding will be helpful for further understanding the critical roles of Hsp4 in ALI and may provide potential targets for ALI diagnosis and treatment.

[Effects of Rg_1 on LPS-induced apoptosis and autophagy of lung epithelial cells].

This paper aimed to study the protective effect of ginsenoside Rg_1 on endotoxin(LPS)-induced apoptosis of lung epithelial cells and its mechanism of action. Mouse lung epithelial cells(MLE-12) were first treated with LPS. The autophagy changes and apoptosis and the relationship with concentration and time of LPS were observed. Then,the level of autophagy in MLE-12 was regulated at a specific concentration and action time of LPS,and the changes of apoptosis were observed. Secondly,ginsenoside Rg_1 and autophagy inhibitor 3-MA were added respectively at the same concentration and action time of LPS. The lung epithelial cells were grouped to observe the effect of ginsenoside Rg_1 on LPS-induced apoptosis of lung epithelial cells and its mechanism. In the animal experiment,the mice were grouped and tested by apoptosis protein,lung injury score and HE staining section to verify whether ginsenoside Rg_1 has a protective effect on LPS-induced lung injury. The results showed that apoptosis and autophagy increased as the rise of concentration after treatment with LPS for 12 h. The apoptosis increased gradually,and the autophagy increased first and then decreased over time at the LPS concentration of 25 g·L-1. The apoptosis of LPS group was higher than that of control group,and LPS+3-MA group increased further,while apoptosis decreased significantly in LPS+RAM(rapamycin,autophagy promoter) group. The autophagy increased in LPS group,decreased in LPS+3-MA group and increased in LPS+RAM group. The apoptosis of LPS group was higher than that of control group,and the apoptosis of LPS+Rg_1 group decreased. The apoptosis of LPS+Rg_1+3-MA group increased again. The autophagy of LPS group further increased after administration of ginsenoside Rg_1,but decreased after administration of 3-MA. In the in vivo experiments in mice,the apoptosis of LPS group increased significantly compared with the control group,while LPS + ginsenoside Rg_1 group decreased. Lung injury score and HE staining also conformed to the above trend. LPS can induce the apoptosis of lung epithelial cells in a time-dependent and concentration-dependent manner. The autophagy of lung epithelial cells increases with the rise of LPS concentration. At the specific concentration of LPS,autophagy increases first and then decreases after 12-16 hours. Proper increase of autophagy in lung epithelial cells within a certain period of time can reduce the apoptosis induced by LPS,while inhibition of autophagy can increase apoptosis. Ginsenoside Rg_1 has a protective effect on lung cancer epithelial cell apoptosis induced by autophagy.

E3 ubiquitin ligase tripartite motif 7 positively regulates the TLR4-mediated immune response via its E3 ligase domain in macrophages.

Members of the tripartite motif (TRIM) family as E3 ubiquitin ligases have been regarded as critical regulators of innate immunity and antiviral response. However, the role of TRIM7 is still elusive. Here, we provide evidence for the importance of TRIM7 in regulation of the TLR4-mediated innate response. In detail, we find that TRIM7 is highly expressed in antigen-presenting cells like macrophages. Knockdown of TRIM7 clearly inhibits the LPS-induced production of IFN-ß, TNF-α and IL-6 in macrophages. Conversely, forced expression of TRIM7 could exert an opposite effect on these pro-inflammatory cytokines. Further analysis indicates that such effect is mediated by the TLR4-associated signaling pathways including MAPKs, NF-κB and IRF3-involved pathways. Truncation of the E3 ligase domain on TRIM7 may reduce the production of pro-inflammatory cytokines, suggesting a critical role of this domain in the regulation of LPS-initiated innate response. Taken together, we report here that TRIM7 may facilitate the TLR4-mediated innate response via its E3 ligase domain in macrophages, which provides new insight into the mechanistic role of TRIM7 in innate immunity.