Caloric restriction extends yeast chronological lifespan via a mechanism linking cellular aging to cell cycle regulation, maintenance of a quiescent state, entry into a non-quiescent state and survival in the non-quiescent state

// Anna Leonov 1 , Rachel Feldman 1 , Amanda Piano 1 , Anthony Arlia-Ciommo 1 , Vicky Lutchman 1 , Masoumeh Ahmadi 1 , Sarah Elsaser 1 , Hana Fakim 1 , Mahdi Heshmati-Moghaddam 1 , Asimah Hussain 1 , Sandra Orfali 1 , Harshvardhan Rajen 1 , Negar Roofigari-Esfahani 1 , Leana Rosanelli 1 and Vladimir I. Titorenko 1 1 Department of Biology, Concordia University, Montreal, Quebec, Canada Correspondence to: Vladimir I. Titorenko, email: // Keywords : yeast, cellular aging, cell cycle, cell differentiation, cell quiescence, Gerotarget  Received : June 12, 2017 Accepted : August 14, 2017 Published : September 01, 2017 Abstract A yeast culture grown in a nutrient-rich medium initially containing 2% glucose is not limited in calorie supply. When yeast cells cultured in this medium consume glucose, they undergo cell cycle arrest at a checkpoint in late G1 and differentiate into quiescent and non-quiescent cell populations. Studies of such differentiation have provided insights into mechanisms of yeast chronological aging under conditions of excessive calorie intake. Caloric restriction(definition) is an aging-delaying dietary intervention. Here, we assessed how caloric restriction influences the differentiation of chronologically aging yeast cultures into quiescent and non-quiescent cells, and how it affects their properties. We found that caloric restriction extends yeast chronological lifespan via a mechanism linking cellular aging to cell cycle regulation, maintenance of quiescence, entry into a non-quiescent state and survival in this state. Our findings suggest that caloric restriction delays yeast chronological aging by causing specific changes in the following: 1) a checkpoint in G1 for cell cycle arrest and entry into a quiescent state; 2) a growth phase in which high-density quiescent cells are committed to become low-density quiescent cells; 3) the differentiation of low-density quiescent cells into low-density non-quiescent cells; and 4) the conversion of high-density quiescent cells into high-density non-quiescent cells.