Functional Determinants of Human Enteric α-Defensin HD5

Rajabi, Mohsen; Ericksen, Bryan; Wu, Xueji; Leeuw, Erik de; Zhao, Le; Pazgier, M.; Lu, Wuyuan

doi:10.1074/jbc.m112.367995

Cited by 65 publications

(88 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…HD5 was more potent than HNP1 at a lower range of concentrations, i.e., 0.3 and 3 M, whereas maximal concentrations of these two defensins resulted in similar bactericidal activities, with slightly more strength for HNP1. This agrees with the propensity of HD5 to form aggregates at high concentrations, thus losing available sites to interact with the cell membrane (58). Furthermore, such a different range of activities is compatible with the different physiological roles of HD5 and HNP1.…”

Section: Discussionsupporting

confidence: 69%

New Role for Human α-Defensin 5 in the Fight against Hypervirulent Clostridium difficile Strains

et al. 2015

View full text Add to dashboard Cite

Clostridium difficile infection (CDI), one of the most common hospital-acquired infections, is increasing in incidence and severity with the emergence and diffusion of hypervirulent strains. CDI is precipitated by antibiotic treatment that destroys the equilibrium of the gut microbiota. Human ␣-defensin 5 (HD5), the most abundant enteric antimicrobial peptide, is a key regulator of gut microbiota homeostasis, yet it is still unknown if C. difficile, which successfully evades killing by other host microbicidal peptides, is susceptible to HD5. We evaluated, by means of viability assay, fluorescence-activated cell sorter (FACS) analysis, and electron microscopy, the antimicrobial activities of ␣-defensins 1 and 5 against a panel of C. difficile strains encompassing the most prevalent epidemic and hypervirulent PCR ribotypes in Europe (012, 014/020, 106, 018, 027, and 078). Here we show that (i) concentrations of HD5 within the intestinal physiological range produced massive C. difficile cell killing; (ii) HD5 bactericidal activity was mediated by membrane depolarization and bacterial fragmentation with a pattern of damage peculiar to C. difficile bacilli, compared to commensals like Escherichia coli and Enterococcus faecalis; and (iii) unexpectedly, hypervirulent ribotypes were among the most susceptible to both defensins. These results support the notion that HD5, naturally present at very high concentrations in the mucosa of the small intestine, could indeed control the very early steps of CDI by killing C. difficile bacilli at their germination site. As a consequence, HD5 can be regarded as a good candidate for the containment of hypervirulent C. difficile strains, and it could be exploited in the therapy of CDI and relapsing C. difficile-associated disease.

show abstract

Section: Discussionsupporting

confidence: 69%

New Role for Human α-Defensin 5 in the Fight against Hypervirulent Clostridium difficile Strains

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Residues conferring hydrophobicity and supporting multimerization have been shown to be vital for HD5's antiviral properties in other viral systems (51)(52)(53). Several arginine residues in HD5 have been shown to be critical in its ability to neutralize adenovirus (53).…”

Section: Discussionmentioning

confidence: 99%

The Human Alpha Defensin HD5 Neutralizes JC Polyomavirus Infection by Reducing Endoplasmic Reticulum Traffic and Stabilizing the Viral Capsid

Zins

Nelson

Maginnis

et al. 2014

J Virol

View full text Add to dashboard Cite

“…34 A recent alanine scan identified Leu 29 as a critical determinant for antibacterial activity. 35 Taken together, these investigations overwhelmingly support a model whereby the mechanism of HD5 ox action differs for Gram-negative (e.g. E. coli ) and -positive (e.g.…”

mentioning

confidence: 78%

“…4,35-37 Electrostatic and hydrophobicity depictions of select α-defensins are provided as Supporting Information (Figures S42-S47). The primary amino acid sequence of HD5 contains six arginine residues (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, self-association of HD5 ox was observed by crystallography and surface plasmon resonance (SPR). 10,35,78 A dissociation constant of ca. 2 μM was obtained from SPR experiments conducted at pH 7.4 and in the presence of 150 mM NaCl, attributed to dimer formation; evidence for higher-order oligomers was reported at HD5 ox concentrations greater than ca.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

NMR Solution Structure and Condition-Dependent Oligomerization of the Antimicrobial Peptide Human Defensin 5

et al. 2012

View full text Add to dashboard Cite

Human defensin 5 (HD5) is a 32-residue host-defense peptide expressed in the gastrointestinal, reproductive, and urinary tracts that has antimicrobial activity. It exhibits six cysteine residues that are regiospecifically oxidized to form three disulfide bonds (Cys3—Cys31, Cys5—Cys20, and Cys10—Cys30) in the oxidized form (HD5ox). To probe the solution structure and oligomerization properties of HD5ox, and select mutant peptides lacking one or more disulfide bonds, NMR solution studies and analytical ultracentrifugation experiments are reported in addition to in vitro peptide stability assays. The NMR solution structure of HD5ox, solved at pH 4 in 90:10 H2O/D2O, is presented (PDB: 2LXZ). Relaxation T1/T2 measurements and the rotational correlation time (Tc) estimated from a [15N,1H]-TRACT experiment demonstrate that HD5ox is dimeric under these experimental conditions. Exchange broadening of the Hα signals in the NMR spectra suggests that residues 19-21 (Val19-Cys20-Glu21) contribute to the dimer interface in solution. Exchange broadening is also observed for residues 7-14 comprising the loop. Sedimentation velocity and equilibrium studies conducted in buffered aqueous solution reveal that the oligomerization state of HD5ox is pH-dependent. Sedimentation coefficients of ca. 1.8 S and a molecular weight of 14,363 Da were determined for HD5ox at pH 7, supporting a tetrameric form ([HD5ox] ≥ 30 μM). At pH 2, a sedimentation coefficient of ca. 1.0 S and a molecular weight of 7,079 Da, corresponding to a HD5ox dimer, were obtained. Millimolar concentrations of NaCl, CaCl2, and MgCl2 have negligible effect on the HD5ox sedimentation coefficients in buffered aqueous solution at neutral pH. Removal of a single disulfide bond results in a loss of peptide fold and quaternary structure. These biophysical investigations highlight the dynamic and environment-sensitive behavior of HD5ox in solution, and provide important insights into HD5ox structure/activity relationships and the requirements for antimicrobial action.

show abstract

Functional Determinants of Human Enteric α-Defensin HD5

Cited by 65 publications

References 89 publications

New Role for Human α-Defensin 5 in the Fight against Hypervirulent Clostridium difficile Strains

New Role for Human α-Defensin 5 in the Fight against Hypervirulent Clostridium difficile Strains

The Human Alpha Defensin HD5 Neutralizes JC Polyomavirus Infection by Reducing Endoplasmic Reticulum Traffic and Stabilizing the Viral Capsid

NMR Solution Structure and Condition-Dependent Oligomerization of the Antimicrobial Peptide Human Defensin 5

Contact Info

Product

Resources

About