Structural Proteome Diversity as a Determinant of Hematopoietic Aging

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Hematopoietic stem cells (HSCs) must continually adapt to a range of environmental and physiological stressors that challenge protein homeostasis. While genetic and transcriptional regulation of HSC function has been extensively studied, there is little quantitative understanding of how proteostatic stress influences fate decisions in these cells. This project addresses that gap by integrating controlled perturbations of protein quality control pathways with state-of-the-art phenotypic, transcriptomic, and proteomic analyses. Preliminary work demonstrates that physiologic stressors—such as fever-range hyperthermia and altered oxygen tension—combined with targeted modulation of chaperones, proteasome activity, autophagy, and mitochondrial proteostasis, elicit reproducible and measurable shifts in HSC state.
Aim 1 will systematically map how discrete proteostatic and metabolic stressors remodel high-quality murine HSC populations maintained in defined ex vivo culture conditions. By titrating the intensity of specific perturbations and environmental parameters, this aim will generate a dose-resolved atlas linking proteome remodeling to preservation or loss of stemness. Aim 2 will extend these assays to primary human CD34⁺ stem and progenitor cells to identify conserved stress-response programs that stabilize an HSC-like compartment. Cross-species analysis will define a core set of actionable proteostatic modules that predict favorable versus adverse fate trajectories.
This research is significant because it will produce the first integrated, quantitative map of proteostatic stress–driven state transitions in HSCs. By treating proteostasis, oxygen, and temperature as orthogonal, tunable levers, the project offers an innovative framework for dissecting how environmental and intrinsic cues jointly shape stem cell fate. The resulting insights will not only inform strategies for optimizing ex vivo HSC maintenance, but also provide a foundation for translational approaches to preserve stem cell function in the context of physiological stress.

Grant Number: 1R56DK141457-01A1
NIH Institute/Center: NIH
Principal Investigator: Andre Catic