Influences of developmental metabolic flux on physicochemical properties of the nucleus

About This Grant

Project Summary In development and tissue homeostasis, cells must enact state changes to perform specialized functions. These processes involve significant remodeling of gene expression, cellular morphology, and metabolic flux. Recently, exciting work has uncovered a role for metabolites in driving gene expression during differentiation through effects on histone modifying enzymes, demonstrating that metabolism can directly inform cell state. However, these studies have primarily focused on biochemical gene regulatory mechanisms, overlooking a role for metabolites in dictating mechanical properties of the cell, which are also known to influence cell state. In my postdoctoral work so far, I have found that the biosynthesis of polyamines, a polycationic class of metabolites abundant in undifferentiated cells, decreases during differentiation, and that polyamines enhance histone modifying enzyme activity through electrostatic interactions with the histone tail. My recent data has revealed a surprising connection between nuclear polyamine abundance and the mechanical state of the nuclear envelope, suggesting that polyamines can impact cellular function both at the level of single proteins, and more globally by altering physicochemical properties of intracellular compartments, most significantly the nucleus. Therefore, the guiding hypothesis of this proposal is that the genetic modulation of metabolism impacts differentiation by altering mechanical forces at the nucleus. In Aim 1 I will test the hypothesis that polyamines alter nuclear mechanics by driving osmotic flux into and out of the nucleus, leveraging force spectroscopy and genetically encoded reporters of osmotic stress. In Aim 2 I will ask whether cells regulate an osmotic effect on nuclear envelope tension during differentiation to drive fate transitions, applying functional assays and genomics approaches in 2D and 3D models of mammalian differentiation. As both metabolism and nuclear mechanics are altered in cancer and in aging, completion of this proposal will uncover mechanisms relevant to the etiology and treatment of human disease. Through structured mentorship from my advisory committee, I will gain training in biophysical assays and advanced imaging, which will be critical for my long-term goal of leading an independent research group exploring interactions between metabolism and cellular mechanics. Finally, I will take advantage of the rich career development activities available at Yale University to build skills in laboratory leadership and scientific communication.