| First Author | Grevengoed TJ | Year | 2015 |
| Journal | FASEB J | Volume | 29 |
| Issue | 11 | Pages | 4641-53 |
| PubMed ID | 26220174 | Mgi Jnum | J:230606 |
| Mgi Id | MGI:5763348 | Doi | 10.1096/fj.15-272732 |
| Citation | Grevengoed TJ, et al. (2015) Loss of long-chain acyl-CoA synthetase isoform 1 impairs cardiac autophagy and mitochondrial structure through mechanistic target of rapamycin complex 1 activation. FASEB J 29(11):4641-53 |
| abstractText | Because hearts with a temporally induced knockout of acyl-CoA synthetase 1 (Acsl1(T-/-)) are virtually unable to oxidize fatty acids, glucose use increases 8-fold to compensate. This metabolic switch activates mechanistic target of rapamycin complex 1 (mTORC1), which initiates growth by increasing protein and RNA synthesis and fatty acid metabolism, while decreasing autophagy. Compared with controls, Acsl1(T-/-) hearts contained 3 times more mitochondria with abnormal structure and displayed a 35-43% lower respiratory function. To study the effects of mTORC1 activation on mitochondrial structure and function, mTORC1 was inhibited by treating Acsl1(T-/-) and littermate control mice with rapamycin or vehicle alone for 2 wk. Rapamycin treatment normalized mitochondrial structure, number, and the maximal respiration rate in Acsl1(T-/-) hearts, but did not improve ADP-stimulated oxygen consumption, which was likely caused by the 33-51% lower ATP synthase activity present in both vehicle- and rapamycin-treated Acsl1(T-/-) hearts. The turnover of microtubule associated protein light chain 3b in Acsl1(T-/-) hearts was 88% lower than controls, indicating a diminished rate of autophagy. Rapamycin treatment increased autophagy to a rate that was 3.1-fold higher than in controls, allowing the formation of autophagolysosomes and the clearance of damaged mitochondria. Thus, long-chain acyl-CoA synthetase isoform 1 (ACSL1) deficiency in the heart activated mTORC1, thereby inhibiting autophagy and increasing the number of damaged mitochondria. |
