Mechanical and matrix perturbations in ex vivo lymphoid biasing of hematopoietic stem cells

Immunocompromised patients, including those undergoing chemotherapy, experience prolonged immune dysfunction due to the loss of adaptive immune cells and their progenitors. Hematopoietic stem cells (HSCs) represent a clinically established regenerative cell source; Multi-lymphoid progenitors (MLPs) represent the earliest committed stage of lymphoid differentiation, with lineage restricted Common Lymphoid Progenitors (CLPs) arising from downstream differentiation, yet the culture conditions that bias HSCs toward this fate remain to be investigated. The native extracellular matrix (ECM) architecture derived from decellularized bone marrow is coupled with parametrizable mechanical induction through controlled biaxial strain and cyclic pressure. Biochemical modulation using lymphoid-associated growth factors and signaling pathways is integrated with these components to provide a mechanobiological perspective on early lymphoid bias. Decellularized ECM provides experimentally defined stiffness, composition, and integrin-mediated signaling, while mechanical loading introduces tunable forces relevant to marrow environments. Biochemical cues, including Interleukin Factor 7 (IL-7), Fms-like tyrosine kinase 3 ligand (FLT3L), and Notch Receptor 1 (Notch1) mediated signaling, further guide lineage commitment within the engineered niche. This perspective defines a controlled scientific rationale for probing how matrix support and mechanical perturbation influence early lymphoid bias in HSC cultures. We hypothesize that a coupled mechano-chemical system integrating decellularized bone marrow extracellular matrix with controlled cyclic strain and pressure functions as a primary control axis for early lymphoid commitment, reprogramming hematopoietic stem cell fate toward multi-lymphoid progenitors and then to common lymphoid progenitors in a manner not achievable by cytokine signaling alone.