ADSL and acne: 1. Increased protease activity at lesion sites.2. C. acnes culture supernatant activates PAR2 in keratinocytes, upregulating AMPs and MMPs.3. C. acnes culture supernatant increased the lipid production of SZ95 sebocytes via PAR2.4. Tetracyclines and macrolides relieve acne symptoms by regulating the PAR-2/IL-8 axis.