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Schneider CV, Hehl L, Creasy KT, Vitali C, Vell MS, Vujkovic M, Park J, Scorletti E, Seeling KS, Rendel MD, Conlon DM, Huang H, Zandvakili I, Valmiki S, Schneider KM, Hussain MM, Rader DJ. A coding variant in the microsomal triglyceride transfer protein reduces both hepatic steatosis and plasma lipids. Aliment Pharmacol Ther 2023. [PMID: 37248657 DOI: 10.1111/apt.17566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/14/2023] [Accepted: 05/15/2023] [Indexed: 05/31/2023]
Abstract
BACKGROUND AND AIMS Genetic inactivation and pharmacologic inhibition of the microsomal triglyceride transfer protein (MTP; gene name MTTP) inhibits hepatic secretion of VLDL, thereby reducing serum lipids and apoB at the expense of increasing hepatic steatosis. Little is known about the effects of missense variants in MTTP on hepatic and circulating lipids. METHODS We analysed the association of MTTP missense variants with metabolic, hepatic and clinical phenotypes in the Penn Medicine Biobank (PMBB; n = 37,960) and the UKBiobank (UKB; n = 451,444). RESULTS We analysed 24 missense variants in MTTP in PMBB for association with biopsy-proven hepatic steatosis and found that an isoleucine 128 to threonine variant (I128T: rs3816873-A, frequency 26%) was associated with reduced steatosis (p < 0.001). PMBB subjects with imaging-proven steatosis also revealed significantly fewer carriers of MTTP I128T compared to controls. Analysis in UKB also showed that MTTP I128T was associated with reduced risk of hepatic steatosis. Unexpectedly, MTTP I128T was found to be associated with reduced plasma levels of LDL-cholesterol and apoB (all p < 0.001). Functional studies indicated that MTTP I128T is neither a classic loss nor gain of function allele. CONCLUSIONS MTTP I128T is associated with reduced hepatic steatosis as well as reduced plasma lipids and apoB. This paradoxical profile is not consistent with a simple gain or loss of function in MTP activity and suggests a more complex effect on MTP function. Further investigation of MTTP I128T will provide insight into the structure-function of MTP and potentially new approaches to modulate MTP activity that could both reduce hepatic and circulating lipids.
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Affiliation(s)
- Carolin V Schneider
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Institute for Translational Medicine and Therapeutics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Leonida Hehl
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Kate T Creasy
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cecilia Vitali
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mara S Vell
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Marijana Vujkovic
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joe Park
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eleonora Scorletti
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Institute for Translational Medicine and Therapeutics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katharina S Seeling
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Miriam D Rendel
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Donna M Conlon
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Helen Huang
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Inuk Zandvakili
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Medicine, Division of Gastroenterology and Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Swati Valmiki
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, New York, USA
| | - Kai M Schneider
- Department of Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - M Mahmood Hussain
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, New York, USA
| | - Daniel J Rader
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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