Sirt6 loss activates Got1 and facilitates cleft palate through abnormal activating glycolysis

Cleft palate (CP) is a common congenital craniofacial malformation, which is caused by a combination of genetic and environmental factors. However, its underlying mechanism has not been elucidated. Sirtuin6 (SIRT6) mutation has been associated with craniofacial anomalies in humans. This study further defined the role of Sirt6 in palatogenesis by investigating the specific inactivation of Sirt6 in Wnt1-expressing cell lineages. Here, we demonstrated that Sirt6 conditioned knockout (Sirt6 cKO) could inhibit the osteogenesis of the palate which facilitated the occurrence of CP. Specifically, Sirt6 deficiency promoted the expression of glutamine oxaloacetic transaminase 1 (Got1) and glycolysis through deacetylation inhibition, which increased the proliferation of mouse embryonic palatal mesenchyme (MEPM) cells through the GOT1-lactate dehydrogenase A (LDHA)-transforming growth factor beta receptor 1 (TGFBR1) pathway in the early stage and inhibited the osteogenic differentiation of MEPM cells through the GOT1-LDHA-bone morphogenetic protein 2 (BMP2) pathway in the late stage. Notably, if there was a disturbance of the environment, such as retinoic acid (RA), the occurrence of CP increased. Also, the enhanced acetylation of histone 3 lysine 9 (H3K9) in Got1 induced by Sirt6 deficiency was mediated by the acetylase tat-interacting protein 60 (TIP60) rather than acetyltransferase p300 (P300). Additionally, inhibition of Got1 partially saved the promoting effect of Sirt6 cKO on the CP. Our study reveals the role of Sirt6 in facilitating CP, with Got1 as the primary driver.