Proteomic and phosphoproteomic profiling in heart failure with preserved ejection fraction (HFpEF)

María Valero-Muñoz; Eng Leng Saw; Ryan M Hekman; Benjamin C Blum; Zaynab Hourani; Henk Granzier; Andrew Emili; Flora Sam

doi:10.3389/fcvm.2022.966968

Proteomic and phosphoproteomic profiling in heart failure with preserved ejection fraction (HFpEF)

Front Cardiovasc Med. 2022 Aug 25:9:966968. doi: 10.3389/fcvm.2022.966968. eCollection 2022.

Authors

María Valero-Muñoz¹, Eng Leng Saw¹, Ryan M Hekman^{2

3}, Benjamin C Blum^{3

4}, Zaynab Hourani⁵, Henk Granzier⁵, Andrew Emili^{2

3}, Flora Sam¹

Affiliations

¹ Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States.
² Department of Biology, Boston University, Boston, MA, United States.
³ Department of Biochemistry, Cell Biology and Genomics, Boston University, Boston, MA, United States.
⁴ Center for Network Systems Biology, Boston University, Boston, MA, United States.
⁵ Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ, United States.

Abstract

Although the prevalence of heart failure with preserved ejection fraction (HFpEF) is increasing, evidence-based therapies for HFpEF remain limited, likely due to an incomplete understanding of this disease. This study sought to identify the cardiac-specific features of protein and phosphoprotein changes in a murine model of HFpEF using mass spectrometry. HFpEF mice demonstrated moderate hypertension, left ventricle (LV) hypertrophy, lung congestion and diastolic dysfunction. Proteomics analysis of the LV tissue showed that 897 proteins were differentially expressed between HFpEF and Sham mice. We observed abundant changes in sarcomeric proteins, mitochondrial-related proteins, and NAD-dependent protein deacetylase sirtuin-3 (SIRT3). Upregulated pathways by GSEA analysis were related to immune modulation and muscle contraction, while downregulated pathways were predominantly related to mitochondrial metabolism. Western blot analysis validated SIRT3 downregulated cardiac expression in HFpEF vs. Sham (0.8 ± 0.0 vs. 1.0 ± 0.0; P < 0.001). Phosphoproteomics analysis showed that 72 phosphosites were differentially regulated between HFpEF and Sham LV. Aberrant phosphorylation patterns mostly occurred in sarcomere proteins and nuclear-localized proteins associated with contractile dysfunction and cardiac hypertrophy. Seven aberrant phosphosites were observed at the z-disk binding region of titin. Additional agarose gel analysis showed that while total titin cardiac expression remained unaltered, its stiffer N2B isoform was significantly increased in HFpEF vs. Sham (0.144 ± 0.01 vs. 0.127 ± 0.01; P < 0.05). In summary, this study demonstrates marked changes in proteins related to mitochondrial metabolism and the cardiac contractile apparatus in HFpEF. We propose that SIRT3 may play a role in perpetuating these changes and may be a target for drug development in HFpEF.

Keywords: HFpEF – heart failure with preserved ejection fraction; SIRT3; metabolism; mitochondria; phosphoproteomics; proteomics; titin.