TRPV4 facilitates the reprogramming of inflamed macrophages by regulating IL-10 production via CREB.

Background: Transient receptor potential vanilloid type 4 (TRPV4) is a versatile ion channel with diverse roles in immune cells, including macrophages. While its function in inflammation remains debated, we investigated its role in regulating IL-10 production and its impact on macrophage reprogramming during inflammation.

Methods: We investigated the connection between TRPV4 activation and CREB-mediated IL-10 production during inflammation. Notably, this signaling pathway was found to reprogram macrophages and enhance their ability to resist inflammatory damage. The experiments were conducted on primary macrophages and were further corroborated by animal studies.

Results: In response to TRPV4 activation during inflammation, we observed a significant increase in intracellular Ca²⁺ levels, which triggered the activation of the transcription factor CREB, subsequently upregulating IL-10 production. This IL-10 played a pivotal role in reprogramming macrophages to withstand inflammatory damage. Using a mouse model of acute lung injury (ALI), we confirmed that TRPV4 activation during ALI led to IL-10 secretion, but this increase did not significantly contribute to inflammation resolution. Moreover, we found that TRPV4 prevented the accumulation of dysfunctional mitochondria in macrophages through the CREB-IL-10 axis during inflammation. Suppression of CREB or TRPV4 inhibition exacerbated mitochondrial dysfunction, while treatment with recombinant IL-10 mitigated these effects. Additionally, IL-10 induced mitophagy and cleared dysfunctional mitochondria in LPS-exposed cells.

Conclusion: Our study highlights the essential role of TRPV4 in regulating IL-10 production and mitochondrial health in macrophages during inflammation. These findings contribute to understand the role of TRPV4 in immune responses and suggest potential therapeutic targets for modulating inflammation-induced cellular dysfunction.