Staphylococcal LTA-Induced miR-143 Inhibits Propionibacterium acnes-Mediated Inflammatory Response in Skin

Staphylococcus epidermidis (S. epidermidis) plays a critical role in modulating cutaneous inflammatory responses in skin. Although S. epidermidis has been shown to co-colonize with Propionibacterium acnes (P. acnes) in acne lesions, it is unclear whether S. epidermidis is involved in the regulation of P. acnes-induced inflammatory responses. In this study, we demonstrated that S. epidermidis inhibited P. acnes-induced inflammation in skin. P. acnes induced the expression of interleukin-6 and tumor necrosis factor-α via the activation of toll-like receptor (TLR) 2 in both keratinocytes and mouse ears. Staphylococcal lipoteichoic acid activated TLR2 to induce miR-143 in keratinocytes, and miR-143, in turn, directly targeted 3′ UTR of TLR2 to decrease the stability of TLR2 mRNA and then decreased TLR2 protein, thus inhibiting P. acnes-induced proinflammatory cytokines. The inhibitory effect of miR-143 was further confirmed in vivo as the administration of miR-143 antagomir into mouse ears abrogated the inhibitory effect of lipoteichoic acid on P. acnes-induced inflammation in skin. Taken together, these observations demonstrate that staphylococcal lipoteichoic acid inhibits P. acnes-induced inflammation via the induction of miR-143, and suggest that local modulation of inflammatory responses by S. epidermidis at the site of acne vulgaris might be a beneficial therapeutic strategy for management of P. acnes-induced inflammation.