scholarly journals N-Acetyl-cysteine and Mechanisms Involved in Resolution of Chronic Wound Biofilm

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Xin Li ◽  
Jane Kim ◽  
Jiabin Wu ◽  
Alaa’ I Ahamed ◽  
Yinsheng Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Cell ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Diabetic Mouse ◽  
Bacterial Survival ◽  
Bacterial Cell Death ◽  
Carboxylic Groups ◽  
Acetyl Cysteine

Chronic wounds are a major global health problem with the presence of biofilm significantly contributing to wound chronicity. Current treatments are ineffective in resolving biofilm and simultaneously killing the bacteria; therefore, effective biofilm-resolving drugs are needed. We have previously shown that, together with α-tocopherol, N-acetyl-cysteine (NAC) significantly improves the healing of biofilm-containing chronic wounds, in a diabetic mouse model we developed, by causing disappearance of the bacteria and breakdown of the extracellular polymeric substance (EPS). We hypothesize that NAC creates a microenvironment that affects bacterial survival and EPS integrity. To test this hypothesis, we developed an in vitro biofilm system using microbiome taken directly from diabetic mouse chronic wounds. For these studies, we chose mice in which chronic wound microbiome was rich in Pseudomonas aeruginosa (97%). We show that NAC at concentrations with pH < pKa causes bacterial cell death and breakdown of EPS. When used before biofilm is formed, NAC leads to bacterial cell death whereas treatment after the biofilm is established NAC causes biofilm dismantling accompanied by bacterial cell death. Mechanistically, we show that NAC can penetrate the bacterial membrane, increase oxidative stress, and halt protein synthesis. We also show that low pH is important for the actions of NAC and that bacterial death occurs independently of the presence of biofilm. In addition, we show that both the acetyl and carboxylic groups play key roles in NAC functions. The results presented here provide insight into the mechanisms by which NAC dismantles biofilm and how it could be used to treat chronic wounds after debridement (NAC applied at the start of culture) or without debridement (NAC applied when biofilm is already formed). This approach can be taken to develop biofilm from microbiome taken directly from human chronic wounds to test molecules that could be effective for the treatment of specific biofilm compositions.

scholarly journals Novel Quorum-Sensing Peptides Mediating Interspecies Bacterial Cell Death

mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Sathish Kumar ◽  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Death ◽  
Bacillus Subtilis ◽  
Quorum Sensing ◽  
Bacterial Cell ◽  
Content Type ◽  
E Coli ◽  
New Class ◽  
Bacterial Cell Death ◽  
Induced Module

ABSTRACTEscherichia colimazEFis a toxin-antitoxin stress-induced module mediating cell death. It requires the quorum-sensing signal (QS) “extracellular death factor” (EDF), the penta-peptide NNWNN (EcEDF), enhancing the endoribonucleolytic activity ofE. colitoxin MazF. Here we discovered thatE. coli mazEF-mediated cell death could be triggered by QS peptides from the supernatants (SN) of the Gram-positive bacteriumBacillus subtilisand the Gram-negative bacteriumPseudomonas aeruginosa. In the SN ofB. subtilis, we found one EDF, the hexapeptide RGQQNE, calledBsEDF. In the SN ofP. aeruginosa, we found three EDFs: the nonapeptide INEQTVVTK, calledPaEDF-1, and two hexadecapeptides, VEVSDDGSGGNTSLSQ, calledPaEDF-2, and APKLSDGAAAGYVTKA, calledPaEDF-3. When added to a dilutedE. colicultures, each of these peptides acted as an interspecies EDF that triggeredmazEF-mediated death. Furthermore, though their sequences are very different, each of these EDFs amplified the endoribonucleolytic activity ofE. coliMazF, probably by interacting with different sites onE. coliMazF. Finally, we suggest that EDFs may become the basis for a new class of antibiotics that trigger death from outside the bacterial cells.IMPORTANCEBacteria communicate with one another via quorum-sensing signal (QS) molecules. QS provides a mechanism for bacteria to monitor each other’s presence and to modulate gene expression in response to population density. Previously, we addedE. coliEDF (EcEDF), the peptide NNWNN, to this list of QS molecules. Here we extended the group of QS peptides to several additional different peptides. The new EDFs are produced by two other bacteria,Bacillus subtilisandPseudomonas aeruginosa. Thus, in this study we established a “new family of EDFs.” This family provides the first example of quorum-sensing molecules participating in interspecies bacterial cell death. Furthermore, each of these peptides provides the basis of a new class of antibiotics triggering death by acting from outside the cell.

scholarly journals Topical Antibiotic Elution in a Collagen-Rich Hydrogel Successfully Inhibits Bacterial Growth and Biofilm Formation In Vitro

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Jung Gi Min ◽  
Uriel J. Sanchez Rangel ◽  
Austin Franklin ◽  
Hiroki Oda ◽  
Zhen Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Chronic Wounds ◽  
Treatment Options ◽  
Extracellular Proteins ◽  
Multiple Time ◽  
Content Type ◽  
Biofilm Disruption

ABSTRACT Chronic wounds are a prominent concern, accounting for $25 billion of health care costs annually. Biofilms have been implicated in delayed wound closure, but they are susceptible to developing antibiotic resistance and treatment options continue to be limited. A novel collagen-rich hydrogel derived from human extracellular matrix presents an avenue for treating chronic wounds by providing appropriate extracellular proteins for healing and promoting neovascularization. Using the hydrogel as a delivery system for localized secretion of a therapeutic dosage of antibiotics presents an attractive means of maximizing delivery while minimizing systemic side effects. We hypothesize that the hydrogel can provide controlled elution of antibiotics leading to inhibition of bacterial growth and disruption of biofilm formation. The rate of antibiotic elution from the collagen-rich hydrogel and the efficacy of biofilm disruption was assessed with Pseudomonas aeruginosa. Bacterial growth inhibition, biofilm disruption, and mammalian cell cytotoxicity were quantified using in vitro models. The antibiotic-loaded hydrogel showed sustained release of antibiotics for up to 24 h at therapeutic levels. The treatment inhibited bacterial growth and disrupted biofilm formation at multiple time points. The hydrogel was capable of accommodating various classes of antibiotics and did not result in cytotoxicity in mammalian fibroblasts or adipose stem cells. The antibiotic-loaded collagen-rich hydrogel is capable of controlled antibiotic release effective for bacteria cell death without native cell death. A human-derived hydrogel that is capable of eluting therapeutic levels of antibiotic is an exciting prospect in the field of chronic wound healing.

Effect of alpha-ketoglutarate and N-acetyl cysteine on cyanide-induced oxidative stress mediated cell death in PC12 cells

2010 ◽  
Vol 26 (5) ◽  
pp. 297-308 ◽  
Author(s):  
RM Satpute ◽  
J. Hariharakrishnan ◽  
R. Bhattacharya
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Pc12 Cells ◽  
Caspase 3 ◽  
Critical Role ◽  
Total Antioxidant Status ◽  
Protective Effects ◽  
Simultaneous Treatment ◽  
Acetyl Cysteine

Cyanide is a mitochondrial poison, which is ubiquitously present in the environment. Cyanide-induced oxidative stress is known to play a key role in mediating the neurotoxicity and cell death in rat pheochromocytoma (PC12) cells. PC12 cells are widely used as a model for neurotoxicity assays in vitro. In the present study, we investigated the protective effects of alpha-ketoglutarate (A-KG), a potential cyanide antidote, and N-acetyl cysteine (NAC), an antioxidant against toxicity of cyanide in PC12 cells. Cells were treated with various concentrations (0.625—1.25 mM) of potassium cyanide (KCN) for 4 hours, in the presence or absence of simultaneous treatment of A-KG (0.5 mM) and NAC (0.25 mM). Cyanide caused marked decrease in the levels of cellular antioxidants like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). Lipid peroxidation indicated by elevated levels of malondialdehyde (MDA) was found to be accompanied by decreased levels of reduced glutathione (GSH) and total antioxidant status (TAS) of the cells. Cyanide-treated cells showed notable increase in caspase-3 activity and induction of apoptotic type of cell death after 24 hours. A-KG and NAC alone were very effective in restoring the levels of GSH and TAS, but together they significantly resolved the effects of cyanide on antioxidant enzymes, MDA levels, and caspase-3 activity. The present study reveals that combination of A-KG and NAC has critical role in abbrogating the oxidative stress-mediated toxicity of cyanide in PC12 cells. The results suggest potential role of A-KG and NAC in cyanide antagonism.

The extract of Hypericum ascyron L. induces bacterial cell death through apoptosis pathway

2015 ◽  
Vol 166 ◽  
pp. 205-210 ◽  
Author(s):  
Xiu-Mei Li ◽  
Xue-Gang Luo ◽  
Nan Wang ◽  
Hao Zhou ◽  
Chuan-Ling Si ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Cell ◽  
Apoptosis Pathway ◽  
Bacterial Cell Death

Hydroxychavicol, a key ingredient of Piper betle induces bacterial cell death by DNA damage and inhibition of cell division

2018 ◽  
Vol 120 ◽  
pp. 62-71 ◽  
Author(s):  
Deepti Singh ◽  
Shwetha Narayanamoorthy ◽  
Sunita Gamre ◽  
Ananda Guha Majumdar ◽  
Manish Goswami ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Cell Division ◽  
Bacterial Cell ◽  
Piper Betle ◽  
Bacterial Cell Death

scholarly journals Death effector domain of a mammalian apoptosis mediator, FADD, induces bacterial cell death

2002 ◽  
Vol 35 (6) ◽  
pp. 1540-1549 ◽  
Author(s):  
Sang Won Lee ◽  
Young--gyu Ko ◽  
SookHee Bang ◽  
Key-Sun Kim ◽  
Sunghoon Kim
Keyword(s):  
Cell Death ◽  
Bacterial Cell ◽  
Effector Domain ◽  
Death Effector Domain ◽  
Bacterial Cell Death ◽  
Death Effector

scholarly journals Antibiotic-Induced Bacterial Cell Death Exhibits Physiological and Biochemical Hallmarks of Apoptosis

2012 ◽  
Vol 46 (5) ◽  
pp. 561-572 ◽  
Author(s):  
Daniel J. Dwyer ◽  
Diogo M. Camacho ◽  
Michael A. Kohanski ◽  
Jarred M. Callura ◽  
James J. Collins
Keyword(s):  
Cell Death ◽  
Bacterial Cell ◽  
Bacterial Cell Death ◽  
Physiological And Biochemical

scholarly journals New Adapted In Vitro Technology to Evaluate Biofilm Formation and Antibiotic Activity Using Live Imaging under Flow Conditions

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1746
Author(s):  
Cassandra Pouget ◽  
Catherine Dunyach-Remy ◽  
Alix Pantel ◽  
Sophie Schuldiner ◽  
Albert Sotto ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Cell Imaging ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Live Imaging ◽  
Bacterial Biofilm ◽  
Flow Conditions ◽  
Promising Tool ◽  
Reference Strains

The polymicrobial nature of biofilms and bacterial interactions inside chronic wounds are keys for the understanding of bacterial cooperation. The aim of this present study was to develop a technique to study and visualize biofilm in live imaging under flow conditions (Bioflux™ 200, Fluxion Biosciences). The BiofluxTM system was adapted using an in vitro chronic wound-like medium (CWM) that mimics the environment encountered in ulcers. Two reference strains of Staphylococcus aureus (Newman) and Pseudomonas aeruginosa (PAO1) were injected in the BiofluxTM during 24 h to 72 h in mono and coculture (ratio 1:1, bacteria added simultaneously) in the CWM vs. a control medium (BHI). The quantification of biofilm formation at each time was evaluated by inverted microscopy. After 72 h, different antibiotics (ceftazidime, imipenem, linezolid, oxacillin and vancomycin) at 1x MIC, 10x MIC and 100x MIC were administrated to the system after an automatic increase of the flow that mimicked a debridement of the wound surface. Biofilm studies highlighted that the two species, alone or associated, constituted a faster and thicker biofilm in the CWM compared to the BHI medium. The effect of antibiotics on mature or “debrided” biofilm indicated that some of the most clinically used antibiotic such as vancomycin or imipenem were not able to disrupt and reduce the biofilm biomass. The use of a life cell imaging with an in vitro CWM represents a promising tool to study bacterial biofilm and investigate microbial cooperation in a chronic wound context.

Sign in / Sign up

Export Citation Format

Share Document