Pancreatic islet transplantation still represents a promising therapeutic strategy for curative treatment of type 1 diabetes mellitus. However, a limited number of organ donors and insufficient vascularization with islet engraftment failure restrict the successful transfer of this approach into clinical practice. To overcome these problems, we herein introduce a novel strategy for the generation of prevascularized islet organoids by the fusion of pancreatic islet cells with functional native microvessels. These insulin-secreting organoids exhibit a significantly higher angiogenic activity compared to freshly isolated islets, cultured islets, and non-prevascularized islet organoids. This is caused by paracrine signaling between the b-cells and the microvessels, mediated by insulin binding to its corresponding receptor on endothelial cells. In vivo, the prevascularized islet organoids are rapidly blood-perfused after transplantation by the interconnection of their autochthonous microvasculature with surrounding blood vessels. As a consequence, a lower number of islet grafts are required to restore normoglycemia in diabetic mice. Thus, prevascularized islet organoids may be used to improve the success rates of clinical islet transplantation.

Our results provide evidence for selective alterations in the cytokine profile and distinct barrier impairment kinetic following tandem repeated irritation with SLS and Tol in aged compared with young skin in vivo.

Protein kinase CK2 is a crucial regulator of endothelial cell proliferation, migration and sprouting during angiogenesis. However, it is still unknown whether this kinase additionally affects the angiogenic activity of other vessel-associated cells. In this study, we investigated the effect of CK2 inhibition on primary human pericytes. We found that CK2 inhibition reduces the expression of nerve/glial antigen (NG)2, a crucial factor which is involved in angiogenic processes. Reporter gene assays revealed a 114 bp transcriptional active region of the human NG2 promoter, whose activity was decreased after CK2 inhibition. Functional analyses demonstrated that the pharmacological inhibition of CK2 by CX-4945 suppresses pericyte proliferation, migration, spheroid sprouting and the stabilization of endothelial tubes. Moreover, aortic rings of NG2−/− mice showed a significantly reduced vascular sprouting when compared to rings of NG2+/+ mice, indicating that NG2 is an important regulator of the angiogenic activity of pericytes. In vivo, implanted Matrigel plugs containing CX-4945-treated pericytes exhibited a lower microvessel density when compared to controls. These findings demonstrate that CK2 regulates the angiogenic activity of pericytes through NG2 gene expression. Hence, the inhibition of CK2 represents a promising anti-angiogenic strategy, because it does not only target endothelial cells, but also vessel-associated pericytes.

MicroRNAs (miRNAs) crucially modulate fundamental biologic processes such as angiogenesis. In the present study, we focused on the molecular function of miRNA‐370‐3p (miR‐370) in regulating the angiogenic activity of endothelial cells (ECs). Transfection with miR‐370 mimic (miR‐370m) significantly inhibited the sprouting of human dermal microvascular EC (HDMEC) and HUVEC spheroids and mouse aortic rings, whereas miR‐370 inhibitor (miR‐370i) promoted sprout formation. Additional in vitro assays demonstrated the pleiotropic inhibitory effects of miR‐370m on HDMEC proliferation, migration, and tube formation. Moreover, Matrigel plugs containing miR‐370m‐transfected HDMECs exhibited a reduced microvessel density after implantation into CD1 nude mice when compared with controls. In contrast, miR‐370i exerted proangiogenic effects. Mechanistic analyses revealed that miR‐370 directly targets smoothened (SMO) and down‐regulates bone morphogenetic protein (BMP)‐2 expression in HDMECs. Accordingly, inhibition of SMO by cyclopamine reversed miR‐370i‐induced HDMEC proliferation and migration. In addition, BMP‐2 treatment counteracted miR‐370m‐suppressed tube formation of HDMECs, whereas blockade of BMP‐2 with neutralizing antibody significantly inhibited miR‐370i‐induced tube formation. Taken together, these novel findings indicate that miR‐370 is a potent inhibitor of angiogenesis, which directly targets SMO and BMP‐2.—Gu, Y., Becker, V., Zhao, Y., Menger, M. D., Laschke, M. W. miR‐370 inhibits the angiogenic activity of endothelial cells by targeting smoothened (SMO) and bone morphogenetic protein (BMP)‐2. FASEB J. 33, 7213–7224 (2019). http://www.fasebj.org

MicroRNAs (miRNAs) expressed in endothelial cells (ECs) are powerful regulators of angiogenesis, which is essential for tumor growth and metastasis. Here, we demonstrated that miR-22 is preferentially and highly expressed in ECs, while its endothelial level is significantly downregulated in human non-small cell lung cancer (NSCLC) tissues when compared to matched nontumor lung tissues. This reduction of endothelial miR-22 is possibly induced by NSCLC cell-secreted interleukin-1β and subsequently activated transcription factor nuclear factor-κB. Endothelial miR-22 functions as a potent angiogenesis inhibitor that inhibits all of the key angiogenic activities of ECs and consequently NSCLC growth through directly targeting sirtuin 1 and fibroblast growth factor receptor 1 in ECs, leading to inactivation of AKT/mammalian target of rapamycin signaling. These findings provide insight into the molecular mechanisms of NSCLC angiogenesis and indicate that endothelial miR-22 represents a potential target for the future antiangiogenic treatment of NSCLC.