Exploring Cyclo (-Gly-Pro) for inflammation modulation in atopic dermatitis: a study on streptococcal postbiotics

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by intense itching and eczematous lesions, significantly affecting quality of life. Complex interactions involving genetic predispositions, environmental factors, and immune dysregulation contribute to AD pathogenesis, with impaired skin barriers and Staphylococcus aureus playing critical roles. Recent interest in postbiotics, beneficial compounds derived from probiotics, has opened potential therapeutic avenues.

This study investigates the postbiotic solution derived from three human skin-derived Streptococcus isolates, to identify a core bioactive compound and its therapeutic role in AD.

Using GC-MS and GC-FID, we quantified Cyclo (-Gly-Pro) and assessed its impact on inflammatory biomarkers in an AD-like keratinocyte cell model. The effect of different incubation temperatures on the compound's production was also analyzed. Furthermore, 16S V3-V4 amplicon sequencing was performed to analyze changes in the skin microbiome of AD patients following treatment.

Cyclo (-Gly-Pro) was consistently present across all strains, with production inversely related to incubation temperature, peaking at 25 °C. Our findings suggest that optimized production conditions and potential synergistic effects with other postbiotic components could enhance therapeutic efficacy.

These results support further in vivo research to elucidate the mechanisms and validate the compound's role in AD treatment strategies, potentially leading to novel dermatological therapies.