Mononuclear Cell Line THP-1 Internalizes Bactericidal/Permeability-Increasing Protein by a Non—Receptor-Mediated Mechanism Consistent With Pinocytosis

Burnett, Robert; Lyden, C.; Tindal, Carolyn J.; Cave, Cynthia M.; Marra, Marian N.; Solomkin, Joseph S.

doi:10.1001/archsurg.1996.01430140090023

Cited by 8 publications

(5 citation statements)

References 34 publications

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“…We observed the rapid internalization of exogenous BPI by human macrophages derived from monocytes and the macrophages derived from the THP-1 monocytic cell line. Previous studies reported that biotinylated BPI is quickly incorporated into the THP-1 cell line through pinocytosis in a concentrationindependent fashion [32]. In our experiments, the uptake of rBPI in THP-Ms was also independent of concentration after one hour of treatment.…”

Section: Discussionsupporting

confidence: 74%

Bactericidal Permeability-Increasing Protein (BPI) Inhibits Mycobacterium tuberculosis Growth

Guzmán-Beltrán,

Juárez,

Cruz-Muñoz

et al. 2024

Biomolecules

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Bactericidal permeability-increasing protein (BPI) is a multifunctional cationic protein produced by neutrophils, eosinophils, fibroblasts, and macrophages with antibacterial anti-inflammatory properties. In the context of Gram-negative infection, BPI kills bacteria, neutralizes the endotoxic activity of lipopolysaccharides (LPSs), and, thus, avoids immune hyperactivation. Interestingly, BPI increases in patients with Gram-positive meningitis, interacts with lipopeptides and lipoteichoic acids of Gram-positive bacteria, and significantly enhances the immune response in peripheral blood mononuclear cells. We evaluated the antimycobacterial and immunoregulatory properties of BPI in human macrophages infected with Mycobacterium tuberculosis. Our results showed that recombinant BPI entered macrophages, significantly reduced the intracellular growth of M. tuberculosis, and inhibited the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-α). Furthermore, BPI decreased bacterial growth directly in vitro. These data suggest that BPI has direct and indirect bactericidal effects inhibiting bacterial growth and potentiating the immune response in human macrophages and support that this new protein’s broad-spectrum antibacterial activity has the potential for fighting tuberculosis.

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Section: Discussionsupporting

confidence: 74%

Bactericidal Permeability-Increasing Protein (BPI) Inhibits Mycobacterium tuberculosis Growth

Guzmán-Beltrán,

Juárez,

Cruz-Muñoz

et al. 2024

Biomolecules

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“…Uptake of HNPs may also occur by ‘piggyback phagocytosis’, that is, the ingestion of bacteria to which extracellular defensins were bound (65). An uptake mechanism called unselective adsorptive pinocytosis figures prominently in the uptake of other cationic proteins found in human PMNs, including bactericidal/permeability increasing factor and lactoferrin (309). The same mechanism imports granzyme B (p I , 9.62), a cytotoxic T‐cell molecule that kills bacteria and shares a microbicidal domain with Cathepsin G (310).…”

Section: Domestic and Imported Defensinsmentioning

confidence: 99%

α‐Defensins in human innate immunity

Lehrer¹,

2011

Immunological Reviews

366

377

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Defensins are small, multifunctional cationic peptides. They typically contain six conserved cysteines whose three intramolecular disulfides stabilize a largely β-sheet structure. This review of human α-defensins begins by describing their evolution, including their likely relationship to the Big Defensins of invertebrates, and their kinship to the β-defensin peptides of many if not all vertebrates, and the θ-defensins found in certain non-human primates. We provide a short history of the search for leukocyte-derived microbicidal molecules, emphasizing the roles played by luck (good), preconceived notions (mostly bad), and proper timing (essential). The antimicrobial, antiviral, antitoxic, and binding properties of human α-defensins are summarized. The structural features of α-defensins are described extensively and their functional contributions are assessed. The properties of HD6, an enigmatic Paneth cell α-defensin, are contrasted with those of the four myeloid α-defensins (HNP1-4) and of HD5, the other α-defensin of human Paneth cells. The review ends with a decalogue that may assist researchers or students interested in α-defensins and related aspects of neutrophil function.

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“…For example, recent reports indicate that lipopolysaccharide binding protein, best known for its ability to enhance CD14‐dependent activation of host cells by lipopolysaccharide, promotes phagocytosis of E. coli by macrophages (112) and enhances the clearance of lipopolysaccharide from the blood (237). Similarly, bactericidal/permeability‐increasing protein, a structurally related protein that does not enhance the inflammatory response to lipopolysaccharide, has been shown to inhibit the ability of lipopolysaccharide to activate neutrophils (87) and to promote phagocytosis of lipopolysaccharide by mononuclear cells (29). Soluble CD14 (sCD14) can act to neutralize lipopolysaccharide by effecting transfer to serum lipoproteins (229), which have been shown to effectively neutralize lipopolysaccharide in both in vitro and in vivo experimental systems (51).…”

Section: Bacterial Clearancementioning

confidence: 99%