Endothelial Cell Inflammation and Barriers Are Regulated by the Rab26-Mediated Balance between beta 2-AR and TLR4 in Pulmonary Microvessel Endothelial Cells
MEDIATORS OF INFLAMMATION
Authors: Chen, Huaping; Yuan, Ming; Huang, Chunji; Xu, Zhi; Li, Mingchun; Zhang, Chun; Gao, Zhan; Zhang, Mingzhou; Xu, Jiancheng; Qian, Hang; You, Jiegen; He, Binfeng; Wang, Guansong; Hu, Mingdong
Abstract
Rab26 GTPase modulates the trafficking of cell surface receptors, such as G protein-coupled receptors including 2-adrenergic receptors in some cell types. However, the effect of Rab26 on 2-adrenergic receptor (2-AR) trafficking or/and Toll-like receptor 4 (TLR4) expression in human pulmonary microvascular endothelial cells (HPMECs) is still unclear. Here, we investigated the role of Rab26 in regulating the expression of 2-ARs and TLR4 in HPMECs and the effect of these receptors' imbalance on endothelial cell barrier function. The results showed that there was unbalance expression in these receptors, where 2-AR expression was remarkably reduced, and TLR4 was increased on the cell membrane after lipopolysaccharide (LPS) treatment. Furthermore, we found that Rab26 overexpression not only upregulated 2-ARs but also downregulated TLR4 expression on the cell membrane. Subsequently, the TLR4-related inflammatory response was greatly attenuated, and the hyperpermeability of HPMECs also was partially relived. Taken together, these data suggest that basal Rab26 maintains the balance between 2-ARs and TLR4 on the cell surface, and it might be a potential therapeutic target for diseases involving endothelial barrier dysfunction.
SNRPB promotes the tumorigenic potential of NSCLC in part by regulating RAB26
CELL DEATH & DISEASE
Authors: Liu, Nianli; Wu, Zhiyuan; Chen, Aoxing; Wang, Yuqi; Cai, Dafei; Zheng, Junian; Liu, Yong; Zhang, Longzhen
Abstract
SNRPB is a core component of spliceosome and plays a major role in regulating alternative splicing of the pre-mRNA. However, little is known about its role in cancer to date. In this study, we observe that SNRPB is overexpressed in NSCLC and correlated with poor prognosis in patients with NSCLC. We demonstrate that SNRPB promotes NSCLC tumorigenesis both in vitro and in vivo. Mechanistically, we reveal that RAB26 is a critical target of SNRPB. Suppression of SNRPB leads to retention of intron seven in the RAB26 mRNA and reduced RAB26 mRNA through activation of nonsense-mediated RNA decay (NMD). Moreover, forced expression of RAB26 partially restores the decreased tumorigenicity in NSCLC cells with SNRPB depletion. Our study unveils a novel role of SNRPB in facilitating NSCLC tumorigenesis via regulation of RAB26 expression and proposes that the SNRPB/RAB26 pathway may offer a therapeutic vulnerability in NSCLC.