In atherosclerosis (AS), the activity of vascular endothelial cells could reflect cells’ metabolism and proliferation(Chang, et al., 2022a, Chen, et al., 2021, Zheng, et al., 2022). AS is a life-threatening vascular disease, and m6A modification level is dysregulated in its pathophysiologic processes of AS(Zhao, et al., 2022, Zhou, et al., 2021). Here, we found that m6A reader KIAA1429 upregulated in ox-LDL-induced HUVECs. Moreover, the function and its molecular mechanism in AS progression are of great value for precision targeted therapy.
Here, this research constructed cellular AS model using ox-LDL-induced HUVECs, and results revealed that m6A level increased upon ox-LDL administration. Because the deregulated m6A level in ox-LDL-induced HUVECs, we assumed that m6A regulators might participate in HUVECs’ pathophysiology.
In the initial screening, we detected several m6A key enzymes (i.e. KIAA1429, METTL3, WTAP) to discovery the up-regulated or down-regulated elements. Finally, we focused on the novel m6A writer KIAA1429 and then explored its functions. To attract attention that the expression of KIAA1429 increased upon ox-LDL administration and this increasing showed a dosage-dependent manner.
Functional assays illustrated that KIAA1429 overexpression repressed proliferation and migration of HUVECs, while KIAA1429 knockdown recovered the proliferation and migration. As is known to all that the ability of proliferation/migration of vascular endothelial cell is very critical for the vascular bio-function. Thus, in these findings, KIAA1429 regulated the proliferation and migration of HUVECs, which significantly showed the roles of KIAA1429 on HUVECs.
Increasing evidence synergistically indicates the potential vital roles of m6A modification on AS(Fu, et al., 2021). For instance, ox-LDL remarkably stimulation promotes the m6A modification level of macrophages in AS and METTL3 knockdown inhibits the oxLDL-induced inflammatory response and m6A modification (Li, et al., 2022c). Besides, ALKBH5 low-expression significantly increases SPHK1 m6A mRNA methylation, in contrast, METTL3 overexpression reduces expression of SPHK1 mRNA(Kumari, et al., 2021). In vascular endothelium of atherogenic inflammatory cascades, METTL3-mediated RNA hypermethylation up-regulates NLRP1 mRNA transcript and down-regulates KLF4 transcript via YTHDF1/YTHDF2 m6A reader proteins(Chien, et al., 2021). Thus, these findings suggest the vital functions of m6A on AS.
The online tool suggested that there were m6A modified site on ROCK2 mRNA (Figure 3C). Moreover, we performed RIP-PCR (Figure 3E, 4D) and MeRIP-PCR (Figure 4A, 4B) to identify the molecular interaction within KIAA1429 and ROCK2 mRNA. In the pathophysiology of AS, ROCK2 functions as an essential element in AS(Takeda, Matoba, Kawanami, Nagai, Akamine, Ishizawa, Kanazawa, Yokota and Utsunomiya, 2019). For instance, circCHMP5/ROCK2 axis regulates cell cycle, proliferation, angiogenesis and inflammation in ox-LDL-induced HUVECs(Li, et al., 2022a). CircUSP36/ROCK2 axis regulates cell apoptosis and inflammatory responses, and promotes cell migration and invasion in ox‑LDL‑induced injury for HUVECs(Miao, et al., 2021). Here, we found that ROCK2 up-regulated in the ox-LDL-induced HUVECs. KIAA1429 targeted the m6A modified site of ROCK2 mRNA and then up-regulated the mRNA stability of ROCK2. Therefore, in this results, KIAA1429/ROCK2 axis accelerated the proliferation and migration of HUVECs.
For the deficiencies and defects, we talk briefly about what we've found in this research. Firstly, being limited by the laboratory external conditions, in vivo assays were unable to proceed as we initially assumed. Moreover, clinical sample research was difficult to put into practice due to the COVID-19. Furthermore, our understanding of m6A is still in its infancy because of the absence of more research. With the great development of m6A and Epigenomics, it would be greatly help to the contribution of our work to the field of AS.