LL-37, the sole human member of the cathelicidin family of antimicrobial peptides (AMPs), stands as a cornerstone of the human innate immune system. Derived from the precursor protein hCAP18, this 37-amino acid peptide, supplied by NINGBO INNO PHARMCHEM CO.,LTD., is critically involved in the body's first line of defense against pathogens and plays a significant role in various physiological processes, including inflammation, tissue repair, and immunomodulation. With its unique amphipathic alpha-helical structure (CAS No. 154947-66-7; Molecular Weight: 4493.37 g/mol), LL-37 embodies a complex interplay of protective and regulatory functions.

Beyond its well-established antimicrobial capabilities, which involve disrupting bacterial cell membranes and inhibiting biofilm formation, LL-37 exhibits a remarkable array of immunomodulatory activities. It can both suppress the inflammatory response induced by Toll-like receptor (TLR) 2 and TLR4 activation by interacting with bacterial lipids like LPS, and conversely, enhance the activation of nucleic acid-sensing TLRs such as TLR3, TLR7, TLR8, and TLR9. This duality highlights its sophisticated role in fine-tuning immune responses. Furthermore, LL-37 actively promotes cell proliferation and migration, contributing significantly to wound closure and tissue homeostasis. Its influence extends to inducing angiogenesis and regulating apoptosis, underscoring its broad impact on cellular functions.

Recent groundbreaking research has shed light on LL-37's involvement in lipid metabolism, particularly its unexpected role in the development of atherosclerosis. Studies indicate that LL-37 can enhance the uptake of low-density lipoprotein (LDL) by macrophages and endothelial cells, a crucial step in the formation of atherosclerotic plaques. This occurs through a unique mechanism where LL-37 binds to and remodels LDL particles, facilitating their internalization via classical LDL receptors like LDLR, SR-B1, and CD36. This increased lipid accumulation within cells can trigger downstream transcriptional changes associated with heightened cholesterol uptake. The implications are profound: chronic inflammatory disorders such as psoriasis, rosacea, inflammatory bowel diseases (IBD), and rheumatoid arthritis (RA), which are characterized by elevated circulating levels of LL-37, are now understood to be intrinsically linked to an increased risk of cardiovascular disease, with LL-37 potentially serving as a key mechanistic link. This discovery positions LL-37 as a critical research target for understanding and potentially mitigating cardiovascular risks in these patient populations.

The structural characteristics of LL-37, including its hydrophobic face and charge distribution, are crucial for its diverse activities, particularly its capacity to bind and remodel LDL. While the clinical translation of AMPs like LL-37 faces challenges, such as limited bioavailability and production costs, ongoing research into modified versions, like SAAP-148 (a synthetic analog with enhanced antimicrobial and antibiofilm properties), offers promising avenues. The detailed understanding of LL-37's molecular mechanisms and its pleiotropic effects, ranging from fighting infection to influencing cardiovascular health, makes it an invaluable subject for biochemical and pharmaceutical development.

As a leading manufacturer and supplier of high-quality biochemicals, NINGBO INNO PHARMCHEM CO.,LTD. is dedicated to providing LL-37 for research and development purposes. For laboratories and companies looking to buy or purchase this essential cathelicidin peptide, NINGBO INNO PHARMCHEM CO.,LTD. offers competitive price options and reliable supply, ensuring researchers have access to premium-grade materials for their cutting-edge studies. The continued investigation into LL-37's multifaceted roles promises to unlock new diagnostic and therapeutic strategies for a wide spectrum of human diseases.