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Distinct hypertrophic cardiomyopathy genotypes result in convergent sarcomeric proteoform profiles revealed by top-down proteomics

journal contribution
posted on 16.11.2020, 22:26 by T Tucholski, W Cai, ZR Gregorich, EF Bayne, SD Mitchell, SJ McIlwain, WJ de Lange, M Wrobbel, H Karp, Z Hite, PG Vikhorev, SB Marston, S Lal, Amy Li, C dos Remedios, T Kohmoto, J Hermsen, JC Ralphe, TJ Kamp, RL Moss, Y Ge
© 2020 National Academy of Sciences. All rights reserved. Hypertrophic cardiomyopathy (HCM) is the most common heritable heart disease. Although the genetic cause of HCM has been linked to mutations in genes encoding sarcomeric proteins, the ability to predict clinical outcomes based on specific mutations in HCM patients is limited. Moreover, how mutations in different sarcomeric proteins can result in highly similar clinical phenotypes remains unknown. Posttranslational modifications (PTMs) and alternative splicing regulate the function of sarcomeric proteins; hence, it is critical to study HCM at the level of proteoforms to gain insights into the mechanisms underlying HCM. Herein, we employed high-resolution mass spectrometry-based top-down proteomics to comprehensively characterize sarcomeric proteoforms in septal myectomy tissues from HCM patients exhibiting severe outflow track obstruction (n = 16) compared to nonfailing donor hearts (n = 16). We observed a complex landscape of sarcomeric proteoforms arising from combinatorial PTMs, alternative splicing, and genetic variation in HCM. A coordinated decrease of phosphorylation in important myofilament and Z-disk proteins with a linear correlation suggests PTM cross-talk in the sarcomere and dysregulation of protein kinase A pathways in HCM. Strikingly, we discovered that the sarcomeric proteoform alterations in the myocardium of HCM patients undergoing septal myectomy were remarkably consistent, regardless of the underlying HCM-causing mutations. This study suggests that the manifestation of severe HCM coalesces at the proteoform level despite distinct genotype, which underscores the importance of molecular characterization of HCM phenotype and presents an opportunity to identify broad-spectrum treatments to mitigate the most severe manifestations of this genetically heterogenous disease.

Funding

Financial support was provided by NIH R01 HL096971 (to Y.G.). Y.G. also acknowledges R01 GM117058, GM125085, HL109810, and S10 OD018475. T.T. acknowledges support from the NIH Chemistry-Biology Interface Training Program T32 GM008505. W.C. acknowledges American Heart Association predoctoral fellowship 17PRE33660224. S.D.M. acknowledges support from NIH Training Grant T32 GM008688. T.J.K. acknowledges NSF Grant EEC-1648035 and NIH grants R01 HL129798 and U01 HL134764. R.L.M. acknowledges support of NIH Grant R01 HL139883. P.G.V. and S.B.M. acknowledge the British Heart Foundation (PG/17/5/32705). We thank James Anderson, the Surgical Recovery and Organ Preservation Manager, and Carrie Sparks, the Data Coordinator for Organ and Tissue Donation Office at University of Wisconsin, for their assistance in compiling donor data. We also thank Samantha Knott for assistance with graphics for our paper.

History

Publication Date

06/10/2020

Journal

Proceedings of the National Academy of Sciences of USA

Volume

117

Issue

40

Pagination

10p. (p. 24691-24700)

Publisher

National Academy of Sciences

ISSN

0027-8424

Rights Statement

The Author reserves all moral rights over the deposited text and must be credited if any re-use occurs. Documents deposited in OPAL are the Open Access versions of outputs published elsewhere. Changes resulting from the publishing process may therefore not be reflected in this document. The final published version may be obtained via the publisher’s DOI. Please note that additional copyright and access restrictions may apply to the published version.

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