Reprogramming macrophage mechanosensation via TRPV4 modulating mechano-immunotherapy controls fibrotic encapsulation of biomaterial implants

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Abstract
Modulating how macrophages sense mechanical cues offers a novel strategy to control fibrosis around implanted biomaterials. We term this approach ‘mechano-immunotherapy’, which involves the desensitization of immune mechanosensory pathways to control the host response. Here, we use RN-1734 (RN), a model small molecule to demonstrate the proof-of-concept that pharmacologically disrupting macrophage mechanosensation can mitigate fibrosis. In vitro, RN reduced calcium influx and pro-inflammatory cytokine secretion in J774. a2 macrophages. These effects were strictly context-dependent with efficacy observed only in macrophages on high-stiffness (10% w/v) GelMA hydrogels, with no significant impact on those in softer (5% w/v) hydrogels. In vivo, RN selectively attenuated fibrotic capsule formation around implanted electrospun scaffolds but not smooth hydrogels. Notably, despite hydrogels releasing ∼6-fold more drug than scaffolds, fibrosis was reduced only in the scaffold group, suggesting that therapeutic efficacy is driven by the inhibition of high mechanosensory input rather than the loaded drug concentration alone. Spatial transcriptomics revealed that macrophages acted as the primary mechanosensors at the tissue-implant interface. Unsupervised global principal component analysis revealed that RN acted predominantly on early day 3 macrophages. The strongest effect was observed in surface-adhered mechanosensitive macrophages, where RN treatment enhanced their M2-like phenotype and promoted their dispersal from clustered aggregates into broader distribution within the scaffold. This redistribution was accompanied by a marked reduction in the recruitment of interstitial macrophages from the surrounding tissue, which were enriched for matrix-forming gene signatures. Together, these findings suggest that pharmacological desensitization of immune mechanosensors may represent a promising, context-specific approach to improve biomaterial integration.
Funding Information
  • NSW Ministry of Health
  • Snow Medical
  • Australian Research Council
  • National Heart Foundation of Australia

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