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    Abstract:
    ABSTRACT Endogenous antimicrobial peptides of the cathelicidin family contribute to innate immunity. The emergence of widespread antibiotic resistance in many commonly encountered bacteria requires the search for new bactericidal agents with therapeutic potential. Solid-phase synthesis was employed to prepare linear antimicrobial peptides found in cathelicidins of five mammals: human (FALL39/LL37), rabbit (CAP18), mouse (mCRAMP), rat (rCRAMP), and sheep (SMAP29 and SMAP34). These peptides were tested at ionic strengths of 25 and 175 mM against Pseudomonas aeruginosa , Escherichia coli , Staphylococcus aureus , and methicillin-resistant Staphylococcus aureus . Each peptide manifested activity against P. aeruginosa irrespective of the NaCl concentration. CAP18 and SMAP29 were the most effective peptides of the group against all test organisms under both low- and high-salt conditions. Select peptides of 15 to 21 residues, modeled on CAP18 (37 residues), retained activity against the gram-negative bacteria and methicillin-sensitive S. aureus , although the bactericidal activity was reduced compared to that of the parent peptide. In accordance with the behavior of the parent molecule, the truncated peptides adopted an α-helical structure in the presence of trifluoroethanol or lipopolysaccharide. The relationship between the bactericidal activity and several physiochemical properties of the cathelicidins was examined. The activities of the full-length peptides correlated positively with a predicted gradient of hydrophobicity along the peptide backbone and with net positive charge; they correlated inversely with relative abundance of anionic residues. The salt-resistant, antimicrobial properties of CAP18 and SMAP29 suggest that these peptides or congeneric structures have potential for the treatment of bacterial infections in normal and immunocompromised persons and individuals with cystic fibrosis.
    Keywords:
    Cathelicidin
    Lipid II
    One characteristic abnormality of lesional skin in psoriasis is the excessive production of antimicrobial peptides and proteins (AMPs). AMPs typically are small (12-50 amino acids), have positive charge and amphipathic structure, and are found in all living organisms including mammals, insects, plants and invertebrates. These peptides are best known for their integral role in killing pathogenic microorganisms; however, in vertebrates, they are also capable of modifying host inflammatory responses by a variety of mechanisms. In psoriatic lesions, many AMPs are highly expressed, and especially the associations between psoriasis and cathelicidin, β-defensins or S100 proteins have been well studied. Among them, a cathelicidin peptide, LL-37, has been highlighted as a modulator of psoriasis development in recent years. AMPs had been thought to worsen psoriatic lesions but recent evidence has also suggested the possibility that the induction of AMPs expression might improve aspects of the disease. Further investigations are needed to uncover a previously underappreciated role for AMPs in modulating the immune response in psoriasis, and to improve disease without the risks of systemic immunosuppressive approaches.
    Cathelicidin
    Pathogenesis
    Antimicrobial peptides(AMPs)are one kind of polypeptides produced by living organisms' defense system. Substantial evidence accumulated in recent years indicates that AMPs not only possess direct antimicrobial activities but also have multiple immunomodulatory activities. They play an important role in both the innate and adaptive immunity of the host. Their expressions are closely related to many human diseases. Thus, antimicrobial peptides may have potential applications as new therapeutics agents. The intent of this article is to review the structures, expression and bioactivities of defensins and cathelicidin, the main families of AMPs in human. Correlations between human diseases and antimicrobial peptides are also discussed.
    Cathelicidin
    Citations (0)
    Antimicrobial peptides (AMP) are evolutionary ancient molecules produced by nearly all living organisms, both prokaryotic and eukaryotic cells. More than 2000 AMPs have now been identified. These peptides are produced by most human cell types, such as those in the skin and mucous membranes and blood. Each tissue has a different spectrum of AMPs. Antimicrobial capacity depends on the structural characteristics such as charge and amphiphilicity that allow the insertion and/or penetration of AMP into the membranes of microorganisms or other cells. AMPs may have importance in the pathogenesis of neurodegenerative diseases and type 2 diabetes. The most investigated AMPs are defensins and cathelicidin LL-37.
    Cathelicidin
    Beta defensin
    Citations (0)
    Research on antimicrobial peptides has gained pace to exploit their potential and ability to replace conventional antibiotics. Antimicrobial peptides are important members of the host defense system, as they have a broad ability to kill microbes. Antimicrobial peptides and proteins form an important means of host defense in eukaryotes. Large antimicrobial proteins (>100 a.a.), are often lytic, nutrient-binding proteins or specifically target the microbial macromolecules. Small antimicrobial peptides act by disrupting the structure or function of microbial cell membranes. A multitude of antimicrobial peptides has been found in the epithelial layers, phagocytes, and body fluids of multicellular animals including humans. Aside from their role as endogenous antibiotics, antimicrobial peptides have functions in inflammation, wound repair, and regulation of the adaptive immune system. In this review, we discuss recent patents relating to antimicrobial peptides. These patents are related to the method of identifying peptides that have antimicrobial activity, including the papillosin antimicrobial peptide and its encoding gene, the antimicrobial peptide isolated from Halocynthia aurantium, retrocyclins, and the use of cathelicidin LL-37 and its derivatives for wound healing. These patents provide valuable information that could be useful in the identification of antimicrobial peptides and the exploitation of their therapeutic potential.
    Cathelicidin
    Citations (26)
    Inflammatory skin diseases such as atopic dermatitis (AD) and rosacea were complicated by barrier abrogation and deficiency in innate immunity. The first defender of epidermal innate immune response is the antimicrobial peptides (AMPs) that exhibit a broad-spectrum antimicrobial activity against multiple pathogens, including Gram-positive and Gram-negative bacteria, viruses, and fungi. The deficiency of these AMPs in the skin of AD fails to protect our body against virulent pathogen infections. In contrast to AD where there is a suppression of AMPs, rosacea is characterized by overexpression of cathelicidin antimicrobial peptide (CAMP), the products of which result in chronic epidermal inflammation. In this regard, AMP generation that is controlled by a key ceramide metabolite S1P-dependent mechanism could be considered as alternate therapeutic approaches to treat these skin disorders, i.e., Increased S1P levels strongly stimulated the CAMP expression which elevated the antimicrobial activity against multiple pathogens resulting the improved AD patient skin.
    Cathelicidin
    Beta defensin
    Sphingolipid
    Citations (34)
    Background – Antimicrobial peptides (AMPs) have a pivotal role in cutaneous innate immunity. They are present in the skin of many animals, including mammals, and are both constitutively present and inducible by infection and injury. Functions – Antimicrobial peptides exhibit antimicrobial activity against bacteria, viruses, fungi and parasites, with different potencies depending on their peptide structure. They also act as multifunctional effector molecules that influence diverse cellular processes, including cell migration, proliferation and differentiation, cytokine production, angiogenesis and wound healing. Suppressed AMP production has been associated with increased susceptibility to microbial insults and the pathogenesis of atopic dermatitis. This review highlights recent observations on the expression and role of AMPs, particularly the AMPs cathelicidin and β‐defensin, in healthy and diseased skin.
    Cathelicidin
    Beta defensin
    Pathogenesis