scholarly journals A ligand-insensitive UNC5B splicing isoform regulates angiogenesis by promoting apoptosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Davide Pradella ◽  
Gianluca Deflorian ◽  
Alex Pezzotta ◽  
Anna Di Matteo ◽  
Elisa Belloni ◽  
...  

AbstractThe Netrin-1 receptor UNC5B is an axon guidance regulator that is also expressed in endothelial cells (ECs), where it finely controls developmental and tumor angiogenesis. In the absence of Netrin-1, UNC5B induces apoptosis that is blocked upon Netrin-1 binding. Here, we identify an UNC5B splicing isoform (called UNC5B-Δ8) expressed exclusively by ECs and generated through exon skipping by NOVA2, an alternative splicing factor regulating vascular development. We show that UNC5B-Δ8 is a constitutively pro-apoptotic splicing isoform insensitive to Netrin-1 and required for specific blood vessel development in an apoptosis-dependent manner. Like NOVA2, UNC5B-Δ8 is aberrantly expressed in colon cancer vasculature where its expression correlates with tumor angiogenesis and poor patient outcome. Collectively, our data identify a mechanism controlling UNC5B’s necessary apoptotic function in ECs and suggest that the NOVA2/UNC5B circuit represents a post-transcriptional pathway regulating angiogenesis.

2022 ◽  
Author(s):  
Caitlin R Francis ◽  
Hayle Kincross ◽  
Erich J Kushner

In early blood vessel development, trafficking programs, such as those using Rab GTPases, are tasked with delivering vesicular cargo with high spatiotemporal accuracy. However, the function of many Rab trafficking proteins remain ill-defined in endothelial tissue; therefore, their relevance to blood vessel development is unknown. Rab35 has been shown to play an enigmatic role in cellular behaviors which differs greatly between tissue-type and organism. Importantly, Rab35 has never been characterized for its potential contribution in sprouting angiogenesis; thus, our goal was to map Rab35s primary function in angiogenesis. Our results demonstrate that Rab35 is critical for sprout formation; in its absence apicobasal polarity is entirely lost in vitro and in vivo. To determine mechanism, we systematically explored established Rab35 effectors and show that none are operative in endothelial cells. However, we find that Rab35 partners with DENNd1c, an evolutionarily divergent guanine exchange factor, to localize to actin. Here, Rab35 regulates actin polymerization, which is required to setup proper apicobasal polarity during sprout formation. Our findings establish that Rab35 is a potent regulator of actin architecture during blood vessel development.


2020 ◽  
Vol 10 (4) ◽  
pp. 490-501
Author(s):  
Mozhgan Jahani ◽  
Davood Rezazadeh ◽  
Parisa Mohammadi ◽  
Amir Abdolmaleki ◽  
Amir Norooznezhad ◽  
...  

Blood vessel development is one of the most prominent steps in regenerative medicine due tothe restoration of blood flow to the ischemic tissues and providing the rapid vascularizationin clinical-sized tissue-engineered grafts. However, currently tissue engineering technique isrestricted because of the inadequate in vitro/in vivo tissue vascularization. Some challenges likeas transportation in large scale, distribution of the nutrients and poor oxygen diffusion limit theprogression of vessels in smaller than clinically relevant dimensions as well in vivo integration.In this regard, the scholars attempted to promote the vascularization process relied on the stemcells (SCs), growth factors as well as exosomes and interactions of biomaterials with all of themto enable the emergence of ideal microenvironment which is needed for treatment of unhealthyorgans or tissue regeneration and formation of new blood vessels. Thus, in the present reviewwe aim to describe these approaches, advances, obstacles and opportunities as well as theirapplication in regeneration of heart as a prominent angiogenesis-dependent organ.


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