SIRT6 Knockdown in Buffalo Fetal Fibroblasts Exacerbates Premature Senescence Caused by DNA and Telomere Damage.

As a gene with antiaging functions, sirtuin6 (SIRT6) belonging to the sirtuin family plays a vital role in DNA repair, telomerase function, and cellular senescence, as well as maintains epigenomic stability and promotes longevity. However, its role in cell senescence in large animals, such as buffaloes, remains unknown. Fibroblasts are commonly used for somatic reprogramming, and their physiological characteristics affect the efficiency of this process. We aimed to elucidate the role of SIRT6 in cellular senescence and proliferation and analyze its effect on the biological function of buffalo fibroblasts to help improve the efficiency of buffalo somatic cell reprogramming. The expression of SIRT6 and related DNA damage was measured in buffalo fibroblasts obtained at different developmental stages (in the fetus and at 3 and 10 years of age), and the effect of SIRT6 knockdown on the senescence of buffalo fetal fibroblast was investigated. An inverse relationship was observed between SIRT6 expression and senescence in buffalo fibroblasts obtained from animals of various ages. This was accompanied by decreased cell growth, viability, and increased DNA damage. Short hairpin RNA-mediated SIRT6 knockdown accelerated the senescence of buffalo fetal fibroblasts. It blocked the cell cycle during in vitro cell culture, which further enhanced DNA damage, particularly with respect to the telomeres. Collectively, our findings suggest that SIRT6 expression was closely associated with buffalo senescence in fibroblasts. These findings serve as a foundation to better understand the cellular functions of SIRT6 and also aid in selecting donor cells for buffalo somatic cell reprogramming.