PROJECT SUMMARY/ABSTRACT
Excess body weight is a significant contributor to mortality rates in the United States,
with class 2+ obesity increasing the risk of mortality by up to 91%. Physical activity plays
a crucial role in managing prevalent diseases such as obesity, type 2 diabetes, and
cardiovascular disease. Recently, exercise-stimulated myokines have been found to
play a crucial role in inter-tissue signaling, promoting metabolic health and
cardioprotection. However, the mechanism by which myokine expression is activated is
poorly understood. Furthermore, therapeutically effective myokines are yet to be
identified. Mitochondrial Precursor Overaccumulation Stress (mPOS) is a novel
mediator of mitochondria-induced stress signaling, triggered by mitochondrial protein
import stress and the accumulation of unimported mitochondrial proteins in the cytosol.
In our preliminary study, we found the drastic activation of candidate myokines in a
newly established mouse model of mPOS. This is accompanied with a strong lean
phenotype and increased cardiac ejection fraction. These observations invited the
hypothesis that mPOS may mediate myokine signaling, which ultimately promotes
metabolic and cardiac health. In this predoctoral fellowship application, we will test the
hypothesis that mitochondrial protein import stress can specifically induce myokine
signaling by specific transcriptional factors in a bioenergetic-independent manner
(Specific Aim 1). We will also test the hypothesis that mPOS-induced myokine release
mediates fat loss and the improvement of cardiac health during aging (Specific Aim 2).
Success of the proposed research represents a significant advancement in
understanding mitochondria-induced myokine signaling and its potential implications for
metabolic and cardiovascular health. Utilizing the murine and cell-based models, this
study will uncover the mechanisms underlying myokine signaling and its impact on inter-
tissue communication. These findings may lead to the discovery of novel health-
promoting myokines and identification of therapeutic targets for metabolic and
cardiovascular diseases, offering potential interventions to improve overall health,
especially for aging populations and individuals unable to engage in physical exercise.