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Bose HS, Whittal RM, Marshall B, Rajapaksha M, Wang NP, Bose M, Perry EW, Zhao ZQ, Miller WL. A Novel Mitochondrial Complex of Aldosterone Synthase, Steroidogenic Acute Regulatory Protein, and Tom22 Synthesizes Aldosterone in the Rat Heart. J Pharmacol Exp Ther 2021; 377:108-120. [PMID: 33526603 DOI: 10.1124/jpet.120.000365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Aldosterone, which regulates renal salt retention, is synthesized in adrenocortical mitochondria in response to angiotensin II. Excess aldosterone causes myocardial injury and heart failure, but potential intracardiac aldosterone synthesis has been controversial. We hypothesized that the stressed heart might produce aldosterone. We used blue native gel electrophoresis, immunoblotting, protein crosslinking, coimmunoprecipitations, and mass spectrometry to assess rat cardiac aldosterone synthesis. Chronic infusion of angiotensin II increased circulating corticosterone levels 350-fold and induced cardiac fibrosis. Angiotensin II doubled and telmisartan inhibited aldosterone synthesis by heart mitochondria and cardiac production of aldosterone synthase (P450c11AS). Heart aldosterone synthesis required P450c11AS, Tom22 (a mitochondrial translocase receptor), and the intramitochondrial form of the steroidogenic acute regulatory protein (StAR); protein crosslinking and coimmunoprecipitation studies showed that these three proteins form a 110-kDa complex. In steroidogenic cells, extramitochondrial (37-kDa) StAR promotes cholesterol movement from the outer to inner mitochondrial membrane where cholesterol side-chain cleavage enzyme (P450scc) converts cholesterol to pregnenolone, thus initiating steroidogenesis, but no function has previously been ascribed to intramitochondrial (30-kDa) StAR; our data indicate that intramitochondrial 30-kDa StAR is required for aldosterone synthesis in the heart, forming a trimolecular complex with Tom22 and P450c11AS. This is the first activity ascribed to intramitochondrial StAR, but how this promotes P450c11AS activity is unclear. The stressed heart did not express P450scc, suggesting that circulating corticosterone (rather than intracellular cholesterol) is the substrate for cardiac aldosterone synthesis. Thus, the stressed heart produced aldosterone using a previously undescribed intramitochondrial mechanism that involves P450c11AS, Tom22, and 30-kDa StAR. SIGNIFICANCE STATEMENT: Prior studies of potential cardiac aldosterone synthesis have been inconsistent. This study shows that the stressed rat heart produces aldosterone by a novel mechanism involving aldosterone synthase, Tom22, and intramitochondrial steroidogenic acute regulatory protein (StAR) apparently using circulating corticosterone as substrate. This study establishes that the stressed rat heart produces aldosterone and for the first time identifies a biological role for intramitochondrial 30-kDa StAR.
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Affiliation(s)
- Himangshu S Bose
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Randy M Whittal
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Brendan Marshall
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Maheshinie Rajapaksha
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Ning Ping Wang
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Madhuchanda Bose
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Elizabeth W Perry
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Zhi-Qing Zhao
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Walter L Miller
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
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