Cells receive instructive cues from their surrounding microenvironment. The biophysical properties (stiffness, viscoelasticity, biotransport) and biochemical properties (composition) of the microenvironment undergo alterations during both normal and abnormal tissue development. Within the Gilchrist lab, we seek to understand how age-related changes to the microenvironment support age-related cellular dysfunction. To do so, there are three major aims within the lab:
Dynamic in vivo microenvironments
In order to understand how the environment contributes to age-related dysfunction of cells, we must establish how the environment changes with age. We perform material and molecular characterization of human tissues spanning different age (young, middle-aged, and aged) to establish a baseline of age-related microenvironment properties. Characterization and properties of interest includes small amplitude oscillatory shear rheology, nanoindentation, viscoelastic models, strain-stiffening, fatty acid profiles, metabolomics, and proteomics. We are especially interested in age-related changes to the bone marrow, which is the primary location of hematopoietic stem cells.
Designer matrix for cell culture
The in vivo microenvironment is a complex mixture of cells, insoluble and soluble factors, and extracellular matrix (ECM). The ECM provides infrastructure that serves as the structural foundation that not only mechanically supports cells but also regulates the biotransport of factors. To understand the underlying mechanisms that drive cellular aging, we engineer designer materials inspired by the in vivo environment. Using a combination of protein assembly and chemical strategies, we engineer polymer-based hydrogels with defined biophysical properties (stiffness, stress relaxation, strain-stiffening) and biochemical properties (ligand-binding motifs). We take advantage of established tools such as click-chemistry, protein expression, and polymeric modeling to create new synthetic, bioinspired materials
Designer cells for on-demand aging
Stem cells are at the apex of maintaining tissue homeostasis and repair. As we age, stem cells undergo various changes, including the accumulation of genetic mutations, alterations in epigenetic signatures, and shifts in metabolic profiles. In the case of hematopoietic stem cells, ~90% of age-related clonal hematopoiesis events involve the occurrence of just five specific genetic mutations. To study the role of the microenvironment in regulating and promoting the aging of the stem cell compartment, we use cell editing technologies (such as CRISPR/Cas9) to impart an aged genotype. By creating designer cells, we can induce aging on-demand in cells grown in young and aged microenvironments.