Cells resident to precision templated 40-& mu;m pore scaffolds generate small extracellular vesicles that affect CD4+T cell phenotypes through regulatory TLR4 signaling

Precision porous templated scaffolds (PTS) are a hydrogel construct of uniformly sized interconnected spherical pores that induce a pro-healing response (reducing the foreign body reaction, FBR) exclusively when the pores are 30-40 & mu;m in diameter. Our previous work demonstrated the necessity of Tregs in the maintenance of PTS pore size specific differences in CD4+ T cell phenotype. Work here characterizes the role of Tregs in the responses to implanted 40 & mu;m and 100 & mu;m PTS using WT and FoxP3+ cell (Treg) depleted mice. Proteomic analyses indicate that integrin signaling, monocytes/macrophages, cytoskeletal remodeling, inflammatory cues, and vesicule endocytosis may participate in Treg activation and the CD4+ T cell equilibrium modulated by PTS resident cell-derived small extracellular vesicles (sEVs). The role of MyD88-dependent and MyD88-independent TLR4 activation in PTS cell-derived sEV-to-T cell signaling is quantified by treating WT, TLR4ko, and MyD88ko splenic T cells with PTS cell-derived sEVs. STAT3 and mTOR are identified as mechanisms for further study for pore-size dependent PTS cell-derived sEV-to-T cell signaling.Statement of significanceUnique cell populations colonizing only within 40 & mu;m pore size PTS generate sEVs that resolve inflamma-tion by modifying CD4 + T cell phenotypes through TLR4 signaling.& COPY; 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Precision porous templated scaffolds (PTS) are hydrogel constructs that induce pro-healing response when the pores are 30-40 μm in diameter. Tregs play a role in maintaining the pore size specific differences in CD4+ T cell phenotype. Proteomic analyses suggest that integrin signaling, monocytes/macrophages, cytoskeletal remodeling, inflammatory cues, and vesicule endocytosis are involved in Treg activation and CD4+ T cell equilibrium modulated by PTS resident cell-derived small extracellular vesicles (sEVs). The role of TLR4 signaling in PTS cell-derived sEV-to-T cell signaling is investigated.