Identification of a cell-penetrating peptide domain from human beta-defensin 3 and characterization of its anti-inflammatory activity

Abstract

Human beta-defensins (hBDs) are crucial factors of intrinsic immunity that function in the immunologic response to a variety of invading enveloped viruses, bacteria, and fungi. hBDs can cause membrane depolarization and cell lysis due to their highly cationic nature. These molecules participate in antimicrobial defenses and the control of adaptive and innate immunity in every mammalian species and are produced by various cell types. The C-terminal 15-mer peptide within hBD3, designated as hBD3-3, was selected for study due to its cell- and skin-penetrating activity, which can induce anti-inflammatory activity in lipopolysaccharide-treated RAW 264.7 macrophages. hBD3-3 penetrated both the outer membrane of the cells and mouse skin within a short treatment period. Two other peptide fragments showed poorer penetration activity compared to hBD3-3. hBD3-3 inhibited the lipopolysaccharide-induced production of inducible nitric oxide synthase, nitric oxide, and secretory cytokines, such as interleukin-6 and tumor necrosis factor in a concentration-dependent manner. Moreover, hBD3-3 reduced the interstitial infiltration of polymorphonuclear leukocytes in a lung inflammation model. Further investigation also revealed that hBD3-3 downregulated nuclear factor kappa B-dependent inflammation by directly suppressing the degradation of phosphorylated-IκBα and by downregulating active nuclear factor kappa B p65. Our findings indicate that hBD3-3 may be conjugated with drugs of interest to ensure their proper translocation to sites, such as the cytoplasm or nucleus, as hBD3-3 has the ability to be used as a carrier, and suggest a potential approach to effectively treat inflammatory diseases.

Potential role of an antimicrobial peptide, KLK in inhibiting lipopolysaccharide-induced macrophage inflammation

“…Further investigations are required to verify these possible mechanisms of action. Nevertheless, our results would provide a unique property of a peptide with anti-inflammatory potential, and support previous observation that the ability of peptides to block LPS-induced responses does not rely exclusively on the ability to bind to LPS [ 37 , 38 ].…”

“…Another possibility is that the KLK peptide may penetrate macrophages and subsequently interfere with signaling molecules in the inflammatory pathway to inhibit inflammation. A range of AMPs have been recognized as cell-penetrating peptides and have also been reported to be capable of inhibiting NF-κB signaling and suppressing inflammation [ 36 , 37 ]. Further investigations are required to verify these possible mechanisms of action.…”

Porphyromonas gingivalis activates NFκB and MAPK pathways in human oral epithelial cells

“…Additionally, in a model of lung inflammation, hBD3-3 was shown to reduce interstitial infiltration by neutrophils. HBD3-3 was able to downregulate the nuclear factor-kappa B (NF-κB)-dependent inflammatory response via direct suppression of the phosphorylated-nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκBα) degradation and downregulation of the p65 unit of activated NF-κB [25]. …”

Synthetic Human β Defensin-3-C15 Peptide in Endodontics: Potential Therapeutic Agent in Streptococcus gordonii Lipoprotein-Stimulated Human Dental Pulp-Derived Cells

“…However, this therapeutic application of full length HBD3 is limited by its molecular size, the complexity of disulfide pairing, and attenuated activity at elevated ionic strength. To overcome these limitations and identify the active peptide fragments within HBD3, the C-terminal HBD3 peptide was modified by substituting serine for cysteine residues, and shown to have retained its anti-microbial activity [42]. Recent reports showed that HBD3-C15 peptide could attenuate LPS-induced bone resorption, by disrupting podosome belt formation in osteoclasts and suppressing their differentiation [43].…”