Study on the anti-inflammatory and lipid-lowering activities of novel chimeric peptide

Acne was treated by combining the N-terminal of HPA3NT3 (where Lys in position 13 was replaced by Asn) and the C-terminal antibacterial peptide HAG of GLP-1 (32-36) amide pentapeptide after amino replacement. The minimal inhibitory concentration (MIC) was measured using the broth dilution method to evaluate HAG's antibacterial activity. HAG's cytotoxicity was determined using water-soluble tetrazolium salt (WST-1). Interleukin-8 (IL-8) expression in human immortalized keratinocytes (HaCaT) cells stimulated by Propionibacterium acnes and treated with HAG was measured by Enzyme-linked immunosorbent assay (ELISA). IL-8 and toll-like receptor 2 (TLR2) expression was detected using real-time reverse transcriptase polymerase chain reaction (qRT-PCR) to analyze HAG's anti-inflammatory effect in vitro. The total RNA was extracted using SiO2 nanoparticles. Oil red O staining was used to detect the intracellular lipid drop of Sebaceous Gland Cell Line (SZ95), and ELISA was used to detect triglyceride levels. Hematoxylin-eosin (HE) staining was used to evaluate ear edema induced by Propionibacterium acne in mice. The MIC of HAG in Propionibacterium acnes was 6.3 mu g/mL, and 50 mu g/mL of HAG showed cytotoxicity. HAG significantly reduced TLR2 and IL-8 expression in HaCaT cells. Oil red O staining showed that the lipid distribution of HAG-treated SZ95 and triglyceride secretion decreased. HAG reduced ear swelling induced by Propionibacterium acnes. HAG has anti-bacterial and anti-inflammatory effects, excellent hypolipidemic function, and low cytotoxicity. Further development of HAG could be a promising and effective reagent for acne therapy.