Mettl14-driven senescence-associated secretory phenotype (SASP) facilitates somatic reprogramming. Mettl14-driven senescence-associated secretory phenotype (SASP) facilitates somatic reprogramming

The METTL3-METTL14 complex, as the "writer" of N6-methyladenosine (m6A), plays an important role in many biological processes. Previous studies have shown that overexpression of Mettl3 can increase the level of m6A and promotes somatic cell reprogramming. Here, we demonstrate that Mettl14, another component of the methyltransferase (MTase) complex, can significantly enhance the generation of induced pluripotent stem cells (iPSCs) in m6A independent manner. Cooperating with Oct4, Sox2, Klf4 and c-Myc (OSKM), Mettl14 transiently increased the senescence-associated secretory phenotype (SASP) gene expression in the non-reprogramming cells at the late reprogramming stage. The conditional medium in reprogramming intermediates overexpressing Mettl4 or its mutant could enhanced the reprogramming, so do IL-6, a component of SASP. Corespondingly, blocking of SASP using senolytic agent or NF-κB inhibitor impairs the effect of Mettl14 on reprogramming. . Our work highlights the m6A independent function of Mettl14 and provides new insight into the interplay between senescence and reprogramming in vitro. Overall design: The reprogrammable MEFs derived from the transgenic mice carrying the tetO-OSKM transgene and Oct4-GFP/Rosa26-M2rtTA were used in the experiments. The reprogrammable MEFs that were not induced with doxycycline were designated as “MEF” . The reprogrammable cells with or without Obox1’s overexpression were induced with doxycycline (1ug/ml) for 3 days. The cells were harvested and performed RNA sequencing (RNA-seq) .