LL-37 · research summary

LL-37-MRGPRX2-Mast Cell Signaling in Rosacea: Current Evidence and Directions for Human Studies.

Clinical, cosmetic and investigational dermatology · 2026. Summary drawn from the study's full text. Each statement is followed by the exact sentence it comes from. This is a research summary, not medical advice.

Study type

Critical narrative review
“This critical narrative review examines evidence relevant to LL-37–Mas-related G protein-coupled receptor X2 (MRGPRX2)–mast-cell signaling in rosacea and considers the relevance of these findings to future human studies.”

Subjects

Literature on human rosacea tissue, human mast-cell systems, and LL-37-induced mouse models
“Current studies of the LL-37–MRGPRX2–mast-cell candidate branch have been conducted mainly in three experimental settings: human rosacea tissue, human mast-cell and receptor systems, and LL-37-induced mouse models.”

Sample size

Not applicable as this is a review of existing literature
“No new data were created or analyzed in this study.”

Duration

Literature search performed up to September 13, 2026
“The literature search was conducted primarily in PubMed and Web of Science Core Collection, without a predefined lower publication-year limit, and the final search was performed on September 13, 2026.”

Reported findings

Human tissue studies show increased mast-cell abundance or degranulation-associated staining and MRGPRX2 localization in lesional mast cells
“Human rosacea tissue studies show changes in mast-cell abundance or degranulation-associated staining and localize MRGPRX2 to lesional mast cells.”
Human mast-cell studies demonstrate LL-37-responsive MRGPRX2 calcium signaling and degranulation that can be pharmacologically inhibited
“Human mast-cell and receptor studies demonstrate LL-37-responsive MRGPRX2 calcium signaling and degranulation and show pharmacological inhibition of MRGPRX2-mediated responses.”
Direct selective functional testing of MRGPRX2 in patients with rosacea is currently lacking
“Direct selective functional testing of MRGPRX2 in patients with rosacea remains lacking, and receptor-level functional findings and patient-level observations still arise largely from different study settings.”

Limitations stated by the authors

Findings are distributed across different experimental settings, and human MRGPRX2 and murine MrgprB2 are pharmacologically distinct
“However, evidence relevant to the role of human MRGPRX2 in rosacea remains distributed across different experimental and clinical settings.”

Source: PubMed 42861262 · DOI 10.2147/CCID.S648503 · all study summaries

Subjects

Literature on human rosacea tissue, human mast-cell systems, and LL-37-induced mouse models

“Current studies of the LL-37–MRGPRX2–mast-cell candidate branch have been conducted mainly in three experimental settings: human rosacea tissue, human mast-cell and receptor systems, and LL-37-induced mouse models.”

Reported findings

Human tissue studies show increased mast-cell abundance or degranulation-associated staining and MRGPRX2 localization in lesional mast cells

“Human rosacea tissue studies show changes in mast-cell abundance or degranulation-associated staining and localize MRGPRX2 to lesional mast cells.”

Human mast-cell studies demonstrate LL-37-responsive MRGPRX2 calcium signaling and degranulation that can be pharmacologically inhibited

“Human mast-cell and receptor studies demonstrate LL-37-responsive MRGPRX2 calcium signaling and degranulation and show pharmacological inhibition of MRGPRX2-mediated responses.”

Direct selective functional testing of MRGPRX2 in patients with rosacea is currently lacking

“Direct selective functional testing of MRGPRX2 in patients with rosacea remains lacking, and receptor-level functional findings and patient-level observations still arise largely from different study settings.”