Defensin beta 4A (DEFB4A)

Defensin beta 4A (DEFB4A) is a human antibiotic peptide of the beta-defensin family, encoded on chromosome 8, and primarily expressed in epithelial tissues (skin, respiratory tract, and mucosa)[1][2][5][6]. It exhibits broad antimicrobial activity against Gram-negative and Gram-positive bacteria, yeast, and fungi, with the highest potency against Gram-negative species[2][3][6]. The peptide functions by binding negatively charged microbial membranes and disrupting their integrity, often via interactions with plasma membrane lipids (such as PIP2)[3]. DEFB4A also plays a role in immune signaling: it acts as a ligand for the C-C chemokine receptor 6 (CCR6), inducing chemotactic recruitment of immature dendritic cells and memory T cells[2][6]. Its expression is upregulated by inflammatory cytokines and vitamin D, and downregulated by anti-inflammatory glucocorticoids (e.g. dexamethasone)[1]. Elevated levels are seen in inflammatory and infectious conditions, supporting its utility as a biomarker. Therapeutic challenges include salt sensitivity of activity and suppression by corticosteroids[1][2][6]. DEFB4A is thus regarded as a key component of the innate immune system and is actively researched for its antimicrobial properties. No approved drugs directly target DEFB4A, but its modulation is relevant in inflammatory and infectious diseases[2][6].

Other names

DEFB4ADefensin beta 4ADefensin, beta 2DEFB2DEFB4DEFB102BD-2hBD-2SAP1HBD-2Beta-defensin 2Skin-antimicrobial peptide 1Beta defensin 2Beta-defensin 4ADefensin, beta 4DEFB-2

Not applicable; no direct drugs targeting DEFB4A are reported. However, anti-inflammatory drugs (such as corticosteroids) may suppress its expression.