Engineering synthetic suppressor T cells that execute locally targeted immunoprotective programsT cells with synthetic Notch (synNotch) receptors driving antigen-triggered production of anti-inflammatory payloads. Screening a diverse library of suppression programs, we observed the strongest suppression of cytotoxic T cell attack by the production of both anti-inflammatory factors (interleukin-10, transforming growth factor-β1, programmed death ligand 1) and sinks for proinflammatory cytokines (interleukin-2 receptor subunit CD25). Engineered cells with bespoke regulatory programs protected tissues from immune attack without systemic suppression. Synthetic suppressor T cells protected transplanted beta cell organoids from cytotoxic T cells. They also protected specific tissues from unwanted chimeric antigen receptor (CAR) T cell cross-reaction. Synthetic suppressor T cells are a customizable platform to potentially treat autoimmune diseases, organ rejection, and CAR T cell toxicities with spatial precision.
Human progenitor T-cell differentiation regulated by the mechanical resistance of thymus-mimetic extracellular matricesNicholas Jeffreys, Kyle T Ruark, Joshua Price et al.|bioRxiv (Cold Spring Harbor Laboratory)|2025 Abstract Therapeutic T-cell engineering ex vivo from human hematopoietic stem cells (HSCs) focuses on recapitulating notch1-signaling and α4β1-integrin-mediated adhesion within the thymic niche with supportive stromal cell feeder-layers or surface-immobilized recombinant protein-based engineered thymic niches (ETNs). The relevant Notch1-DLL-4 and α4β1-integrin-VCAM-1 interactions are known to respond to mechanical forces that regulate their bond dissociation behaviors and downstream signal transduction, yet manipulating the mechanosensitive features of these key receptor-ligand interactions in thymopoiesis has been largely ignored in current ETN designs. Here, we demonstrate that human T-cell development from cord blood-derived CD34 + HSCs is regulated via molecular cooperativity in notch1 and integrin-mediated mechanotransduction. Mechanically confining interpenetrating network (IPN) hydrogel-based 3D cell culture comprised of collagen type I and alginate polysaccharides functionalized with DLL-4 and VCAM-1 is used as a model viscoelastic 3D ETN to manipulate human progenitor (pro)T-cell differentiation. This ETN enables orthogonal control of the mechanical and biomolecular features of the thymic niche, including thymopoietic ligand density, modulus, and viscoelastic properties (e.g., stress relaxation kinetics). We identify that soft, viscous matrices that enhance activation of the notch1-pathway, and subsequently notch1 intracellular domain (NICD) nuclear import sustain the T-cell development gene regulatory network during proT-cell differentiation. Conversely, stiff, elastic matrices inhibit HSC commitment to the T-lineage, and rather promotes Myeloid-cell differentiation. Our observations indicate mechanical reciprocity in signaling pathways indispensable to thymopoiesis, and highlights extracellular matrix mechanics as a variable in controlling hematopoietic stem cell fate decisions.