DEFB1 gene

Defensins are a family of microbicidal and cytotoxic peptides produced by neutrophils. The members of the defensin family are very similar in their protein sequence. This gene encodes defensin beta 1, an antimicrobial peptide involved in the resistance of epithelial surfaces to microbial colonization. This gene is located in close proximity to defensin alpha 1, a member of the defensin family. All beta-defensins share antimicrobial properties. Although beta-defensin-1 is expressed by numerous epithelia, the antimicrobial function of this beta-defensin is still unclear. This is due to its largely lacking antibiotic efficiency in experimental approaches (Schroeder BO 2012).

Other functions:

• Keratinocytes express beta-defensin-1 and defensin is increased in proliferating cells (Frye M et al. 2001). Beta-defensin-1 HBD-1 is overexpressed in various cell lines of oral carcinomas (Han Q et al. 2014). Beta-defensin-1 plays a role in the differentiation of keratinocytes. Defensin-beta 1 has a regulatory effect on the development of tight junctions in cultured human keratinocytes (Goto H et al. 2013).
• It also appears to play a moderating role in renal carcinomas and prostate carcinoma.
• Gingival epithelial cell lines to which different amounts (25-200 μg/ml) of green tea extracts or epigallocatechin-3-gallate were added showed an upregulation of beta-defensins 1 and 2.
• Antimicrobial activity: Beta-defensin 1 has antimicrobial activity. Can act as a ligand for the C-C chemokine receptor CCR6. Thus, HBD-1 levels correlate with pulmonary tuberculosis activity (Pohorielova OO et al. 2021). Beta-defensin 1 expression is reduced in alveolar macrophages of HIV-infected patients (Alp S et al. 2005).
• COPD/asthma: Elevated levels of defensin beta 1 can be detected in COPD and severe bronchial asthma. Here, the production of defensin beta depends on the severity of the respiratory disease. Defensin can be regarded as an efficient biomarker (Baines KJ et al. 2015). Defensin beta 1 is also associated with the pathogenesis of cystic fibrosis, among other things.
• Sperm motility: Beta-defensin 1 positively regulates sperm motility and bactericidal activity in a CCR6-dependent manner. Binds to CCR6 and triggers Ca2+ mobilization in sperm, which is important for their motility (Khayamabed R et al. 2020).
• Non-segmental vitiligo: Polymorphisms of the DEFB1 gene (GG genotype and G allele) lead to reduced serum levels of HBD-1 in patients with non-segmental vitiligo (Farag AGA et al. 2023). The polymorphism of the DEFB1 gene may modulate vitiligo risk and contribute to vitiligo development in the Egyptian population.

1. Baines KJ et al. (2015) Airway β-Defensin-1 Protein Is Elevated in COPD and Severe Asthma. Mediators Inflamm 2015:407271.
2. Farag AGA et al. (2023) Human beta-defensin 1 circulating level and gene polymorphism in non-segmental vitiligo Egyptian patients. An Bras Dermatol 98:181-188.
3. Frye M et al. (2001) Expression of human beta-defensin-1 promotes differentiation of keratinocytes. J Mol Med (Berl) 79:275-282.
4. Goto H et al. (2013) Human beta defensin-1 regulates the development of tight junctions in cultured human epidermal keratinocytes. J Dermatol Sci 71:145-148.
5. Han Q et al. (2014) Human beta-defensin-1 suppresses tumor migration and invasion and is an independent predictor for survival of oral squamous cell carcinoma patients. PLoS One 9:e91867.
6. Khayamabed R et al. (2020) Effect of recombinant β-defensin 1 protein on human sperm motility and viability. Andrologia 52(1):e13455.
7. Li Y et al. (2015) Host Avian Beta-Defensin and Toll-Like Receptor Responses of Pigeons following Infection with Pigeon Paramyxovirus Type 1. Appl Environ Microbiol 81:6415-6424.
8. Lombardo Bedran TB et al. (2014) Green tea extract and its major constituent, epigallocatechin-3-gallate, induce epithelial beta-defensin secretion and prevent beta-defensin degradation by Porphyromonas gingivalis. J Periodontal Res 49:615623.
9. Németh BC et al. (2014) Relevance of α-defensins (HNP1-3) and defensin β-1 in diabetes. World J Gastroenterol 20:9128-9137.
10. Pohorielova OO et al. (2021) Human-beta-defensin-1: porgonostic marker of tuberculoisis severity and treatment effectiveness in pulmonary tuberculosis. Wiad Lek 74:1839-1843.
11. Schroeder BO (2012) Human beta-defensin 1: from defense to offence. Z Gastroenterol 50:1171-1175.
12. Wang XF et al. (2015) Antimicrobial activity of human β-defensins against lactic acid bacteria. Nat Prod Res 29:2164-2166.