scholarly journals Therapeutic antimicrobial peptides may compromise natural immunity

2012 ◽  
Vol 8 (3) ◽  
pp. 416-418 ◽  
Author(s):  
Michelle G. J. L. Habets ◽  
Michael A. Brockhurst
Keyword(s):  
Antimicrobial Peptides ◽  
Therapeutic Use ◽  
Innate Immune ◽  
Cross Resistance ◽  
Drug Candidate ◽  
Natural Immunity ◽  
New Class ◽  
Compensatory Adaptation ◽  
Microbial Infections ◽  
Potential Risks

Antimicrobial peptides (AMPs) have been proposed as a promising new class of antimicrobials despite warnings that therapeutic use could drive the evolution of pathogens resistant to our own immunity peptides. Using experimental evolution, we demonstrate that Staphylococcus aureus rapidly evolved resistance to pexiganan, a drug-candidate for diabetic leg ulcer infections. Evolved resistance was costly in terms of impaired growth rate, but costs-of-resistance were completely ameliorated by compensatory adaptation. Crucially, we show that, in some populations, experimentally evolved resistance to pexiganan provided S. aureus with cross-resistance to human-neutrophil-defensin-1, a key component of the innate immune response to infection. This unintended consequence of therapeutic use could drastically undermine our innate immune system's ability to control and clear microbial infections. Our results therefore highlight grave potential risks of AMP therapies, with implications for their development.

scholarly journals The Resistance to Host Antimicrobial Peptides in Infections Caused by Daptomycin-Resistant Staphylococcus aureus

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 96
Author(s):  
Md Saruar Bhuiyan ◽  
Jhih-Hang Jiang ◽  
Xenia Kostoulias ◽  
Ravali Theegala ◽  
Graham J. Lieschke ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Responses ◽  
Antimicrobial Peptides ◽  
Innate Immune ◽  
Cross Resistance ◽  
Infection Model ◽  
Innate Immune Responses ◽  
Persistent Infections ◽  
Zebrafish Infection

Daptomycin is an important antibiotic for the treatment of infections caused by Staphylococcus aureus. The emergence of daptomycin resistance in S. aureus is associated with treatment failure and persistent infections with poor clinical outcomes. Here, we investigated host innate immune responses against clinically derived, daptomycin-resistant (DAP-R) and -susceptible S. aureus paired isolates using a zebrafish infection model. We showed that the control of DAP-R S. aureus infections was attenuated in vivo due to cross-resistance to host cationic antimicrobial peptides. These data provide mechanistic understanding into persistent infections caused by DAP-R S. aureus and provide crucial insights into the adaptive evolution of this troublesome pathogen.

scholarly journals The Lactococcal dgkB (yecE) and dxsA Genes for Lipid Metabolism Are Involved in the Resistance to Cell Envelope-Acting Antimicrobials

2021 ◽  
Vol 22 (3) ◽  
pp. 1014
Author(s):  
Aleksandra Tymoszewska ◽  
Tamara Aleksandrzak-Piekarczyk
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Cytoplasmic Membrane ◽  
Cross Resistance ◽  
Resistant Bacteria ◽  
Membrane Targeting ◽  
Nucleotide Polymorphisms ◽  
Next Generation ◽  
Lipid Ii

The emergence of antibiotic-resistant bacteria led to an urgent need for next-generation antimicrobial agents with novel mechanisms of action. The use of positively charged antimicrobial peptides that target cytoplasmic membrane is an especially promising strategy since essential functions and the conserved structure of the membrane hinder the development of bacterial resistance. Aureocin A53- and enterocin L50-like bacteriocins are highly cationic, membrane-targeting antimicrobial peptides that have potential as next-generation antibiotics. However, the mechanisms of resistance to these bacteriocins and cross-resistance against antibiotics must be examined before application to ensure their safe use. Here, in the model bacterium Lactococcus lactis, we studied the development of resistance to selected aureocin A53- and enterocin L50-like bacteriocins and its correlation with antibiotics. First, to generate spontaneous resistant mutants, L.lactis was exposed to bacteriocin BHT-B. Sequencing of their genomes revealed single nucleotide polymorphisms (SNPs) in the dgkB (yecE) and dxsA genes encoding diacylglycerol kinase and 1-deoxy-D-xylulose 5-phosphate synthase, respectively. Then, selected mutants underwent susceptibility tests with a wide array of bacteriocins and antibiotics. The highest alterations in the sensitivity of studied mutants were seen in the presence of cytoplasmic membrane targeting bacteriocins (K411, Ent7, EntL50, WelM, SalC, nisin) and antibiotics (daptomycin and gramicidin) as well as lipid II cycle-blocking bacteriocins (nisin and Lcn972) and antibiotics (bacitracin). Interestingly, decreased via the SNPs accumulation sensitivity to membrane-active bacteriocins and antibiotics resulted in the concurrently increased vulnerability to bacitracin, carbenicillin, or chlortetracycline. It is suspected that SNPs may result in alterations to the efficiency of the nascent enzymes rather than a total loss of their function as neither deletion nor overexpression of dxsA restored the phenotype observed in spontaneous mutants.

scholarly journals Antimicrobial peptides in patients with anorexia nervosa: comparison with healthy controls and the impact of weight gain

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marie-Christin Bendix ◽  
Michael Stephan ◽  
Mariel Nöhre ◽  
Wally Wünsch-Leiteritz ◽  
Hagen Schmidt ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Weight Gain ◽  
Antimicrobial Peptides ◽  
Pathogenic Bacteria ◽  
Innate Immune ◽  
Effect Sizes ◽  
Healthy Controls ◽  
Clinical Observations ◽  
The Impact

AbstractClinical observations show that patients with anorexia nervosa (AN) are surprisingly free from infectious diseases. There is evidence from studies in Drosophila melanogaster that starvation leads to an increased expression of antimicrobial peptides (AMPs). AMPs are part of the innate immune system and protect human surfaces from colonization with pathogenic bacteria, viruses and fungi. We compared the expression of AMPs between patients with AN and healthy controls (HC) and investigated the influence of weight gain. Using a standardized skin rinsing method, quantitative determination of the AMPs psoriasin and RNase 7 was carried out by ELISA. Even though non-significant, effect sizes revealed slightly higher AMP concentrations in HC. After a mean weight gain of 2.0 body mass index points, the concentration of psoriasin on the forehead of patients with AN increased significantly. We could not confirm our hypotheses of higher AMP concentrations in patients with AN that decrease after weight gain. On the contrary, weight gain seems to be associated with increasing AMP concentrations.

scholarly journals Clinical Applications of Immunotherapy Combination Methods and New Opportunities for the Future

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ece Esin
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Checkpoint Inhibitors ◽  
Innate Immune ◽  
Small Subset ◽  
New Class ◽  
Combination Strategies ◽  
Combination Methods ◽  
Immune Editing ◽  
Cell Death Protein

In the last decade, we have gained a deeper understanding of innate immune system. The mechanism of the continuous guarding of progressive mutations happening in a single cell was discovered and the production and the recognition of tumor associated antigens by the T-cells and elimination of numerous tumors by immune-editing were further understood. The new discoveries on immune mechanisms and its relation with carcinogenesis have led to development of a new class of drugs called immunotherapeutics. T lymphocyte-associated antigen 4, programmed cell death protein 1, and programmed cell death protein ligand 1 are the classes drugs based on immunologic manipulation and are collectively known as the “checkpoint inhibitors.” Checkpoint inhibitors have shown remarkable antitumor efficacy in a broad spectrum of malignancies; however, the strongest and most durable immune responses do not last long and the more durable responses only occur in a small subset of patients. One of the solutions which have been put forth to overcome these challenges is combination strategies. Among the dual use of methods, a backbone with either PD-1 or PD-L1 antagonist drugs alongside with certain cytotoxic chemotherapies, radiation, targeted drugs, and novel checkpoint stimulators is the most promising approach and will be on stage in forthcoming years.

scholarly journals MyD88-Dependent Signaling Affects the Development of Meningococcal Sepsis by Nonlipooligosaccharide Ligands

2006 ◽  
Vol 74 (6) ◽  
pp. 3538-3546 ◽  
Author(s):  
Laura Plant ◽  
Hong Wan ◽  
Ann-Beth Jonsson
Keyword(s):  
Inflammatory Responses ◽  
Innate Immune ◽  
Meningococcal Sepsis ◽  
Wild Type ◽  
Microbial Infections ◽  
In The Wild ◽  
Myeloid Differentiation Factor ◽  
Dependent Pathway ◽  
Meningococcal Strain

ABSTRACT The Toll-like receptors (TLRs) and the adaptor myeloid differentiation factor 88 (MyD88) are important in the innate immune defenses of the host to microbial infections. Meningococcal ligands signaling via TLRs control inflammatory responses, and stimulation can result in fulminant meningococcal sepsis. In this study, we show that the responses to nonlipooligosaccharide (non-LOS) ligands of meningococci are MyD88 dependent. An isogenic LOS-deficient mutant of the serogroup C meningococcal strain FAM20 caused fatal disease in wild type C57BL/6 mice that was not observed in MyD88−/− mice. Fatality correlated with high proinflammatory cytokine and C5a levels in serum, high neutrophil numbers in blood, and increased bacteremia at 24 h postinfection in the wild-type mice. Infection with the parent strain FAM20 resulted in fatality in 100% of the wild-type mice and 50% of the MyD88−/− mice. We conclude that both LOS and another neisserial ligand cause meningococcal sepsis in an in vivo mouse model and confirm that meningococcal LOS can act via both the MyD88- dependent and -independent pathways, while the non-LOS meningococcal ligand(s) acts only via the MyD88-dependent pathway.

scholarly journals Antimicrobial Peptides: Versatile Biological Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Muthuirulan Pushpanathan ◽  
Paramasamy Gunasekaran ◽  
Jeyaprakash Rajendhran
Keyword(s):  
Antimicrobial Peptides ◽  
Recombinant Expression ◽  
Biological Properties ◽  
Biologically Active ◽  
Drug Candidate ◽  
Plant Host ◽  
Immune Modulators ◽  
Signalling Molecule ◽  
Interesting Candidate ◽  
Pharmaceutical Industries

Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.

Biochanin A from Chinese Medicine: An Isoflavone with Diverse Pharmacological Properties

2021 ◽  
pp. 1-21
Author(s):  
Jia Yan ◽  
Panda Qiu ◽  
Xinyu Zhang ◽  
Yuanyuan Zhang ◽  
Linjing Mi ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Clinical Application ◽  
Trifolium Pratense ◽  
Safety Evaluation ◽  
Therapeutic Use ◽  
Biochanin A ◽  
Drug Candidate ◽  
Pharmacological Properties ◽  
Biological Availability ◽  
Trifolium Pratense L

Biochanin A (BCA) is a dietary isoflavone, isolated from the leaves and stems of Trifolium pratense L and many other herbs of Chinese medicine. Recent findings indicated BCA as a promising drug candidate with diverse bioactive effects. On the purpose of evaluating the possibility of BCA in clinical application, this review is trying to provide a comprehensive summary of the pharmacological actions of BCA. The publications collected from PubMed, ScienceDirect, and Wiley databases were summarized for the last 10 years. Then, the potential therapeutic use of BCA on the treatment of various diseases was discussed according to its pharmacological properties, namely, anticancer, anti-inflammatory, anti-bacterial, anti-diabetic, and anti-obesity effects as well as neuroprotective, hepatoprotective, cardioprotective, and osteoprotective effects. BCA might mainly regulate the MAPK, PI3K, NRF2, and NF-kB pathways, respectively, to exert its bioactive effects. However, the limited definitive targets, poor biological availability, and insufficient safety evaluation might block the clinical application of BCA. This review may provide new insights for the development of BCA in the application of related diseases.

scholarly journals Brevinin-2 Drug Family—New Applied Peptide Candidates Against Methicillin-Resistant Staphylococcus aureus and Their Effects on Lys-7 Expression of Innate Immune Pathway DAF-2/DAF-16 in Caenorhabditis elegans

2018 ◽  
Vol 8 (12) ◽  
pp. 2627
Author(s):  
Hui Xie ◽  
Yonghua Zhan ◽  
Xueli Chen ◽  
Qi Zeng ◽  
Dan Chen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Survival Rate ◽  
Caenorhabditis Elegans ◽  
Antimicrobial Peptides ◽  
Real Time ◽  
Innate Immune ◽  
C Elegans ◽  
New Drug ◽  
Immune Pathway ◽  
Innate Immune Pathway

The issue of Staphylococcus aureus (MRSA) developing a resistance to drugs such as methicillin has long been the focus for new drug development. In recent years, antimicrobial peptides, such as small molecular peptides with broad-spectrum antibacterial activity and special antibacterial mechanism, have shown a strong medicinal potential. In particular, the Brevinin-2 family has been shown to have a significant inhibitory effect against gram-positive bacteria (G+). In this study, we researched the influence of MRSA on the behavior and survival rate of nematodes. We established an assay of Caenorhabditis elegans–MRSA antimicrobial peptides to screen for new potent anti-infective peptides against MRSA. From the Brevinin-2 family, 13 peptides that had shown strong effects on G+ were screened for their ability to prolong the lifespan of infected worms. Real-time Polymerase Chain Reaction (PCR) tests were used to evaluate the effect on the innate immune pathway dauer formation defective (DAF)-2/DAF-16 of C. elegans. The assay successfully screened and filtered out four of the 13 peptides that significantly improved the survival rate of MRSA-infected worms. The result of real-time PCR indicated that the mRNA and protein expression levels of lys-7 were consistently upregulated by being treated with four of the Brevinin-2 family. The Brevinin-2 family peptides, including Brevinin-2, Brevinin-2-OA3, Brevinin-2ISb, and Brevinin-2TSa, also played an active role in the DAF-2/DAF-16 pathway in C. elegans. We successfully demonstrated the utility of anti-infective peptides that prolong the survival rate of the MRSA-infected host and discovered the relationship between antibacterial peptides and the innate immune system of C. elegans. We demonstrated the antimicrobial effects of Brevinin-2 family peptides, indicating their potential for use as new drug candidates against MRSA infections.

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