Identification of chronotherapeutic targets related to cardiac changes resulting from thyroid hypofunction: evaluation of the circadian profile of the proteome, phosphoproteome and protein glycosylation in the heart of male and female mice

• Grant number: 25/13729-6
• Support Opportunities: Regular Research Grants
• Start date: November 01, 2025
• End date: October 31, 2028
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Rodrigo Antonio Pelliciari Garcia
• Grantee: Rodrigo Antonio Pelliciari Garcia
• Host Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil
• City of the host institution: Diadema
• Associated researchers: Maria Nathália de Carvalho Magalhães Moraes Figueira Borges ; Martin Young ; Paula Bargi de Souza ; Silvia Carolina Guatimosim Fonseca ; Thiago Verano Braga

Abstract

Thyroid gland hypofunction, or hypothyroidism, significantly affects metabolic processes and the function of various organs and systems, including the heart. Recently, we demonstrated that the molecular clock mechanism in cardiomyocytes is sensitive to hypothyroid and hyperthyroid conditions, showing a differential temporal pattern of sensitivity to T3. This directly impacts the fine-tuning of circadian rhythmicity at the cellular level, altering not only the expression of core clock components but also of clock-controlled genes related to metabolism and cardiac contractility. Although the transcriptional alterations of the circadian clock in cardiomyocytes induced by thyroid states are partially understood, no information is currently available on the circadian profile of the proteome, phosphoproteome, or protein glycosylation in relation to the functional impairments in these cells. Considering that hypothyroidism is the most prevalent thyroid disorder worldwide, primarily affecting females, and that the cardiomyocyte circadian clock is associate to sexual dimorphism in heart transcriptome, this study aims to identify potential therapeutic targets for the metabolic and functional cardiac alterations induced by hypothyroidism by evaluating the circadian dynamics of the proteome, phosphoproteome, and protein glycosylation in the hearts of male and female mice. Using high-resolution mass spectrometry, we intend to map the daily variations in protein content and phosphorylation states, as well as identify the main intracellular pathways altered in hypothyroidism. This will contribute to the understanding of the molecular mechanisms through which thyroid hormone deficiency alters cardiac metabolism and function, highlighting the importance of circadian biology in understanding the cardiovascular effects of this dysfunction. Furthermore, the contribution of a functional circadian clock in cardiomyocytes under experimental thyroid conditions will be investigated using a cardiomyocyte-specific knockout model for the clock gene Bmal1, and by applying an agonist of the clock gene Nr1d1 (SR9009) in cultures of adult cardiomyocytes isolated from hypothyroid animals. Our findings have the potential to enhance the understanding of the pathophysiology of hypothyroid cardiomyopathy by evaluating the daily dynamics of abundance and post-translational modifications of key proteins involved in metabolic pathways, contractile function, and circadian rhythm regulation in cardiomyocytes. Moreover, they may guide the design and development of chronotherapeutic approaches targeting cardiac dysfunctions associated with hypothyroidism. (AU)