G-protein-coupled receptor 120 (GPR120) functions as a receptor for unsaturated long-chain free fatty acids and has an important role in regulating lipid and glucose metabolism. However, a role for GPR120 in the development of tumors has not yet been clarified. Here, we show that GPR120 signaling promotes angiogenic switching and motility of human colorectal carcinoma (CRC) cells. We show that the expression of GPR120 is significantly induced in CRC tissues and cell lines, which is associated with tumor progression. Activation of GPR120 signaling in human CRC promotes angiogenesis in vitro and in vivo, largely by inducing the expression and secretion of proangiogenic mediators such as vascular endothelial growth factor (VEGF), interleukin-8 and cyclooxygenase-2-derived prostaglandin E₂. The PI3K/Akt–NF-κB pathway is activated by GPR120 signaling and is required for GPR120 signaling-induced angiogenic switching in CRC cells. And, GPR120 activation enhances the motility of CRC cells and induces epithelial–mesenchymal transition. Furthermore, in vivo study shows that activation of GPR120 promotes angiogenesis and tumor growth. Finally, we find that GPR120 expression is positively correlated with VEGF expression and inversely correlated with the epithelial marker E-cadherin in CRC tissues. Collectively, our results demonstrate that GPR120 functions as a tumor-promoting receptor in CRC and, therefore, shows promise as a new potential target for cancer therapeutics.

Fulminant hepatic failure (FHF) is a clinical syndrome characterized by sudden and severe impairment of liver function. Mesenchymal stem cells (MSCs) have been proposed as a promising therapeutic approach for FHF. In this study we used Propionibacterium acnes ( P. acnes )-primed, lipopolysaccharide (LPS)-induced liver injury in mice as an animal model of human FHF. We demonstrated that administration of MSCs significantly ameliorated liver injury and improved the survival rates of mice subjected to P. acnes plus LPS-induced FHF. Allogeneic MSCs showed similar treatment efficacy as autologous MSCs did in FHF. Treatment efficacy of MSCs could be attributed to decreased infiltration and activation of CD4+ T cells in the liver, inhibition of T helper 1 cells, and induction of regulatory T cells (Tregs). Moreover, decreased DNA copies of P. acnes were detected in the liver of MSC-treated mice. Intriguingly, a distinct liver population of CD11c+MHCIIhiCD80loCD86lo regulatory dendritic cells (DCs) was induced by MSCs. Moreover, these DCs induced Treg differentiation through transforming growth factor-β production. Further mechanistic studies demonstrated that MSC-derived prostaglandin E2 and one of its receptors, EP4, played essential roles in the differentiation of CD11c+B220− DC precursors into regulatory DCs in a phosphoinositide 3-kinase-dependent manner. Conclusion : MSCs induce regulatory DCs from CD11c+B220− DC precursors. This study elucidates an immunoregulatory mechanism of MSCs and lays a foundation for application of MSCs in FHF therapy. (Hepatology 2014;59:671–682)

Autophagy is an evolutionarily conserved biological process involved in an array of physiological and pathological events. Without proper control, autophagy contributes to various disorders, including cancer and autoimmune and inflammatory diseases. It is therefore of vital importance that autophagy is under careful balance. Thus, additional regulators undoubtedly deepen our understanding of the working network, and provide potential therapeutic targets for disorders. In this study, we found that RNF216 (ring finger protein 216), an E3 ubiquitin ligase, strongly inhibits autophagy in macrophages. Further exploration demonstrates that RNF216 interacts with BECN1, a key regulator in autophagy, and leads to ubiquitination of BECN1, thereby contributing to BECN1 degradation. RNF216 was involved in the ubiquitination of lysine 48 of BECN1 through direct interaction with the triad (2 RING fingers and a DRIL [double RING finger linked]) domain. We further showed that inhibition of autophagy through overexpressio...

Mesenchymal stem cell (MSC)-based therapy is a promising approach to treat various inflammatory disorders including multiple sclerosis. However, the fate of MSCs in the inflammatory microenvironmen...

Background: Mesenchymal stem cells (MSCs) have been widely applied to treat various inflammatory diseases. Inflammatory cytokines can induce both apoptosis and autophagy in MSCs. However, whether autophagy plays a pro- or con-apoptosis effect on MSCs in an inflammatory microenvironment has not been clarified. Methods: We inhibited autophagy by constructing MSCs with lentivirus containing small hairpin RNA to knockdown Beclin-1 and applied these MSCs to a model of sepsis to evaluate therapeutic effect of MSCs. Results: Here we show that inhibition of autophagy in MSCs increases the survival rate of septic mice more than control MSCs, and autophagy promotes apoptosis of MSCs during application to septic mice. Further study demonstrated that autophagy aggravated tumor necrosis factor alpha plus interferon gamma-induced apoptosis of MSCs. Mechanically, autophagy inhibits the expression of the pro-survival gene Bcl-2 via suppressing reactive oxygen species/mitogen-activated protein kinase 1/3 pathway. Conclusions: Our findings indicate that an inflammatory microenvironment-induced autophagy promotes apoptosis of MSCs. Therefore, modulation of autophagy in MSCs would provide a novel approach to improve MSC survival during immunotherapy.

Intake of ω-3 PUFAs have been demonstrated to have positive effects on pregnancy outcome, whose receptor, GPR120, regulates several cellular functions including differentiation, metabolism and immune reaction. However, whether GPR120 is involved in decidualization and pregnancy remains unknown. Decidua tissue from women with normal pregnancy and spontaneous abortion were collected to determine the expression profile of GPR120. Abortion mouse models and artificially induced deciduoma in mice were established to evaluate the effect of GPR120 on pregnancy outcome and in vivo decidualization. HESCs and primary DSCs were used to explore the roles of GPR120 in decidualization and mechanisms involved. We found that GPR120 functioned to promote decidualization by upregulating glucose uptake and pentose-phosphate pathway (PPP) of human endometrial stromal cells. Firstly, the expression of GPR120 in decidua of spontaneous abortion was downregulated compared to normal decidua. Lack of GPR120 predisposed mice to LPS or RU486 induced abortion. Decidualization was augmented by GPR120 via improving GLUT1-mediated glucose uptake and G6PD- mediated PPP. FOXO1 was upregulated by GPR120 via activation of ERK1/2 and AMPK signaling and increased the expression of GLUT1. Furthermore, the expression of chemokines and cytokines in decidual stromal cells was enhanced by GPR120. Lastly, GPR120 agonist ameliorated LPS-induced abortion in the mice. GPR120 plays significant roles in decidualization and the maintenance of pregnancy, which might be a potential target for diagnosis and treatment of spontaneous abortion. FUND: Ministry of Science and Technology of China, National Natural Science Foundation of China, the Program of Science and Technology Commission of Shanghai Municipality.