Abstract
Background: SIRT1 is a deacetylase that has diverse roles in intracellular Ca2+ signaling, metabolism, and cardiovascular disease. SIRT1 increases sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) activity that is essential to buffer the increase in Ca2+ induced by release from the sarcoplasmic reticulum (SR). Our lab has shown that metabolic syndrome (MetS) impairs SERCA activity in coronary smooth muscle cells and causes coronary artery disease in Ossabaw miniature swine. We hypothesized that SIRT1 inhibition and MetS would impair Ca2+ buffering. 
 Methods: CRISPR/Cas9 methods delivered a leucine to proline point mutation in SIRT1 (SIRT1L100P) into the Ossabaw swine genome to compare to wild type (WT) and mimic the naturally occurring mutation in humans and decrease SIRT1 activity. Four treatment groups of juvenile swine were based on genotype and diet: WT Lean, SIRT1 Lean, WT MetS, and SIRT1 MetS. Lean swine were fed normal chow and MetS were fed a hypercaloric, atherogenic diet for 7 months. The left anterior descending coronary artery was harvested and enzymatically digested to obtain cells. Fluorescence microscopy measured the Ca2+ indicator fura-2 in single cells. The cells were exposed to 5 mM caffeine to maximally release stores of Ca2+ from the SR. Ca2+ buffering capacity of each cell was analyzed after the caffeine-induced peak increase to assess Ca2+ efflux and SERCA activity. 
 Results: MetS was confirmed by increased body weight, impaired glucose tolerance, hyperinsulinemia, and hypercholesterolemia. Coronary atherosclerosis was shown by angiography, intravascular ultrasound, and gross imaging. The rapid phase of Ca2+ buffering due to Ca2+ efflux was not affected by SIRT1 mutation or MetS. The slower phase of Ca2+ buffering due to SERCA activity was impaired only by SIRT1 mutation (p<0.0005), not by MetS. 
 Conclusion: SIRT1 mutation alone inhibited SERCA buffering of Ca2+ in coronary smooth muscle. (Support: NIH T35HL110854, DK120240, DK09751.)
Highlights
SIRT1 is a deacetylase that has diverse roles in intracellular Ca2+ signaling, metabolism, and cardiovascular disease
SIRT1 increases sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) activity that is essential to buffer the increase in Ca2+ induced by release from the sarcoplasmic reticulum (SR)
Our lab has shown that metabolic syndrome (MetS) impairs SERCA activity in coronary smooth muscle cells and causes coronary artery disease in Ossabaw miniature swine
Summary
John Reed1, Aish Thamba1, John Strobel2, James Byrd2, Mouhamad Alloosh2, Alex Coutts3, and Michael Sturek2 SIRT1 increases sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) activity that is essential to buffer the increase in Ca2+ induced by release from the sarcoplasmic reticulum (SR). Our lab has shown that metabolic syndrome (MetS) impairs SERCA activity in coronary smooth muscle cells and causes coronary artery disease in Ossabaw miniature swine.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
