Loss of m6A demethylase ALKBH5 promotes post‐ischemic angiogenesis via post‐transcriptional stabilization of WNT5A

Abstract

Background: Post-ischemic angiogenesis is critical for blood flow recovery and ischemic tissue repair. N6-methyladenosine (m6A) plays essential roles in numerous biological processes. However, the impact and connected mechanism of m6A on post-ischemic angiogenesis are not fully understood. Methods: AlkB homolog 5 (ALKBH5) was screened out among several methyltransferases and demethylases involved in dynamic m6A regulation. Cardiac microvascular endothelial cells (CMECs) angiogenesis and WNT family member 5A (WNT5A) stability were analyzed upon ALKBH5 overexpression with adenovirus or knockdown with small interfering RNAs in vitro. The blood flow recovery, capillary, and small artery densities were evaluated in adeno-associated virus (AAV)-ALKBH5 overexpression or ALKBH5 knockout (KO) mice in a hind-limb ischemia model. The same experiments were conducted to explore the translational value of transient silencing of ALKBH5 with adenovirus. Results: ALKBH5 was significantly upregulated in hypoxic CMECs and led to a global decrease of m6A level. ALKBH5 overexpression further reduced m6A level in normoxic and hypoxic CMECs, impaired proliferation, migration, and tube formation only in hypoxic CMECs. Conversely, ALKBH5 knockdown preserved m6A levels and promoted angiogenic phenotypes in hypoxic but not in normoxic CMECs. Mechanistically, ALKBH5 regulated WNT5A expression through post-transcriptional mRNA modulation in an m6A-dependent manner, which decreased its stability and subsequently impeded angiogenesis in hypoxic CMECs. Furthermore, ALKBH5 overexpression hindered blood flow

Characterization of N6-Methyladenosine in Domesticated Yak Testes Before and After Sexual Maturity

“…m 6 A, discovered in the early 1970s, is a reversible and dynamic modification involving the methyltransferase complex (writer), demethylases (erasers), and binding proteins (readers) ( Zhao Y. et al, 2021 ). Methyltransferase complexes, including methyltransferase-like 3 ( METTL3 ), METTL14 , and Wilms’ tumor 1-associated protein ( WTAP ) ( Lin et al, 2017 ), induce methylation, which can be reversed by fat mass and obesity-associated factor ( FTO ) and AlkB homologue 5 ( ALKBH5 ) ( Jia et al, 2011 ; Zheng et al, 2013a ).…”

m6A Methylation in Cardiovascular Diseases: From Mechanisms to Therapeutic Potential

“…They are both Fe(II)/α-ketoglutarate-dependent dioxygenases, and both are members of the ALKBH family ( Zaccara et al, 2019 ). Additionally, FTO and ALKBH5 are both localized to the nucleus, and their knockdown significantly increases m6A-methylation levels ( Shen et al, 2015 ; Shen W. et al, 2021 ; Zhao Y. et al, 2021 ). The discovery of m6A demethylases revealed the reversibility of m6A modification, indicating that m6A modification is a dynamically regulated process ( Wu et al, 2021 ).…”

Emerging roles of the RNA modifications N6-methyladenosine and adenosine-to-inosine in cardiovascular diseases

“…Figure 2 offers an overall summary of studies that have assessed either m 6 A or A-to-I RNA modifications in cardiovascular development, physiology, or disease. 50 , 54 , 55 , 56 , 57 , 58 , 54 , 55 , 56 , 57 , 58 , 68 , 67 , 66 , 65 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , …”