Interferon-24 Regulates the Expression of MMP1 and Dermal Collagen of the Skin

The study investigated the role of Interleukin-24 (IL-24) in skin aging, particularly in relation to exposure to particulate matter (PM), a major component of air pollution. Using high-throughput single-cell RNA sequencing on ex vivo human skin tissues, the researchers found that PM exposure significantly upregulated IL-24 in both keratinocytes and fibroblasts, two key cell types in the skin. Further, PM-induced IL-24 from keratinocytes increased the expression of MMP1, an enzyme involved in collagen degradation, and reduced the production of type I collagen, a major structural protein in the skin. These changes mirror the biochemical alterations seen in aged skin. Additionally, repeated treatment with IL-24 for over 3 weeks induced fibroblast senescence, another hallmark of skin aging. These findings suggest that IL-24 plays a crucial role in PM-induced skin aging and could potentially serve as a therapeutic target.