LL-37

LL-37 is the only human antimicrobial peptide (AMP), a crucial part of the innate immune system, known for its ability to kill bacteria, viruses, and fungi by disrupting their membranes, but also for its wide-ranging roles in inflammation, wound healing, and even potentially cancer, acting as a versatile host defense peptide that recruits immune cells and modulates inflammatory responses. It's derived from a larger protein (hCAP18) and functions by having dual water-attracting (hydrophilic) and fat-attracting (lipophilic) properties, allowing it to target and puncture microbial membranes.

Key Functions & Characteristics:
--Antimicrobial: Directly kills pathogens by damaging their cell walls and membranes.
--Immunomodulator: Recruits immune cells (like neutrophils, monocytes, T cells) to infection sites and regulates inflammatory pathways, sometimes reducing inflammation, other times promoting it.
--Wound Healing: Promotes skin repair (epithelialization) and attracts cells for tissue closure.
--Dual-Natured: It's amphipathic, meaning one end loves water and the other loves fat, which helps it interact with and destroy microbial membranes.
--Source: Produced by neutrophils and various epithelial cells (skin, lungs, gut).

Significance:
--It's a central player in fighting infections, acting as an alternative to traditional antibiotics due to its broad-spectrum activity.
--Its complex role in inflammation also links it to autoimmune diseases like psoriasis, making it a target for new therapies.