Mechanism Of Cell Damage Research Articles

Particulate Matter-Induced Emerging Health Effects Associated with Oxidative Stress and Inflammation.

Environmental pollution continues to increase with industrial development and has become a threat to human health. Atmospheric particulate matter (PM) was designated as a Group 1 carcinogen by the International Agency for Research on Cancer in 2013 and is an emerging global environmental risk factor that is a major cause of death related to cardiovascular and respiratory diseases. PM is a complex composed of highly reactive organic matter, chemicals, and metal components, which mainly cause excessive production of reactive oxygen species (ROS) that can lead to DNA and cell damage, endoplasmic reticulum stress, inflammatory responses, atherosclerosis, and airway remodeling, contributing to an increased susceptibility to and the exacerbation of various diseases and infections. PM has various effects on human health depending on the particle size, physical and chemical characteristics, source, and exposure period. PM smaller than 5 μm can penetrate and accumulate in the alveoli and circulatory system, causing harmful effects on the respiratory system, cardiovascular system, skin, and brain. In this review, we describe the relationship and mechanism of ROS-mediated cell damage, oxidative stress, and inflammatory responses caused by PM and the health effects on major organs, as well as comprehensively discuss the harmfulness of PM.

Combinatorial protection of cochlear hair cells: not too little but not too much.

A number of drugs are toxic to the cochlear sensory cells known as hair cells (HCs), resulting in hearing loss. Treatment with survival-promoting growth factors, antioxidants, and inhibitors of cell death pathways or proteinases have been shown to reduce HC damage in in vivo and/or in vitro animal models. Conversely, translation to humans has often been disappointing. This may be due to the complexity of intracellular damage processes. We hypothesized that combining treatments targeting different cellular processes would be more effective. Using an in vitro model of gentamicin ototoxicity for murine cochlear hair cells, we screened all 56 possible combinations of inhibitors targeting five different cell damage mechanisms, plus the activator of one cell survival pathway, each of which have been shown to be singly effective in preventing HC loss in experimental studies. A high dose of gentamicin (200 μM) was used over three days in culture. All compounds were added at a dosage below that required for significant protection in the assay, and only this single dose was then employed. This was done so that we could more easily detect interactive, as opposed to additive, effects. Increasing protection of hair cells was observed as combinations of compounds were increased from two to four factors, although not all combinations were equally protective. The optimal combination of four compounds consisted of an anti-oxidant, an apoptosis inhibitor, an autophagy inhibitor and a protective growth factor. Increasing the number of factors to five or six resulted in decreased protection. The results support the hypothesis that targeting multiple cellular damage or survival pathways provides more an effective hair cell protection approach. The results help to identify critical interactions among the cellular processes that operate in gentamicin ototoxicity. They also suggest that inhibiting too many biological processes impairs functions critical to HC survival, resulting in decreased protection.

Influencing Factors for the Growth of Cladophora and Its Cell Damage and Destruction Mechanism: Implication for Prevention and Treatment

Cladophora is commonly found in marine and freshwater around the globe and provides productivity for littoral zone microorganisms and invertebrates. The eutrophication of the water body has led to the abnormal proliferation of Cladophora in some water, often in river coast channel outbreaks. Even under the nutritional deficiency systems, such as the central trunk canal of the South-to-North Water Diversion in China, Cladophora’s blooms affect water quality and seriously jeopardize human health. Thus, the structural characteristics of Cladophora cells and spores, the factors affecting the growth of Cladophora cells, and the mechanisms of damage and destruction of Cladophora cells and spores were investigated. Cladophora cells are cylindrical with very thick cell walls. The inner layer of the spore wall is a thin membrane which contains the nucleus of the spore. The growth and spreading of Cladophora cells are affected by various environmental factors such as light, temperature, water depth, water level, nutrient salts, pH, etc. Some physical treatment measures, such as ultrasounds, would destroy the cell walls and membranes of Cladophora by its high-intensity mechanical action. Chemicals and aquatic plant measures can destroy Cladophora cells’ photosynthesis system, antioxidant enzyme systems, proteins, and ultrastructure. Based on the mechanisms for these cell damage and destruction, a combination of measures that are likely to inhibit the growth of Cladophora cells effectively was suggested. Furthermore, the damaged cells of Cladophora could provide some environmental benefits. Aggregated results could provide a scientific basis for further research on the control of blooms of Cladophora or the reuse of Cladophora cells as a natural resource.

Understudied targets of the ischemia-reperfusion injury pathogenesis in liver transplantation

Background. Liver transplantation is currently the most effective method to treat diseases with end-stage liver failure. Complications are most often associated with the initially severe patient condition, imperfect organ preservation methods, the surgical management per se, and immune system incompetence. The most common complications of transplantation include ischemic reperfusion injury, which occurs to some or another extent in each transplanted organ and worsens the course of the postoperative period. The process is based on complex pathophysiological mechanisms of cell damage due to ischemia and inflammation caused by reperfusion.Objective. To summarize current data on the mechanisms of the ischemic reperfusion injury development in liver transplantation and to find the ways to reduce adverse effects.Material and methods. The analysis of data from foreign and homeland experimental and clinical studies on the pathogenesis of ischemic reperfusion injury in liver transplantation has been performed. The search for literature data was carried out in international databases (PubMed/MedLine, ResearchGate, as well as in the scientific electronic library of Russia (eLibrary.RU) for the period from 2020-2024.Conclusion. The analyzed publications have provided various algorithms for the preservation of donor organs, including those using machine perfusion.

Changes of RNA m6A/m5C Modification Regulatory Molecules in Ferroptosis of T2DM Rat Pancreas.

N6-methyladenine (m6A) and 5-methylcytosine (m5C) are two common forms of RNA methylation that play an important role in the epigenetics of type 2 diabetes mellitus (T2DM). One type of cell death, ferroptosis, has been implicated in islet β-cell damage in T2DM. Notably, RNA methylation, an upstream regulatory mechanism of mRNAs, can regulate the expression of ferroptosis signaling molecules, thereby affecting cell proliferation and death. Here, we found that the ferroptosis signaling pathway was activated in pancreas of T2DM rats, followed by significant changes in m6A/m5C modification regulatory molecules. These detection data together with the prediction results that m6A and m5C exist in the mRNAs of ferroptosis molecules, we speculate that m6A and m5C are probably involved in pancreatic cell damage by modifying of ferroptosis signaling molecules. In short, our findings provide a new research idea for future studies on the molecular mechanisms of pancreatic cell damage and point to a new direction for exploring the mechanisms of ferroptosis from the perspective of RNA methylation modification.

Cell Damage Mechanisms during Cryopreservation in a Zwitterion Solution and Its Alleviation by DMSO.

Recently, zwitterions have been proposed as novel cryoprotectants. However, some cells are difficult to cryopreserve using aqueous zwitterion solutions alone. We investigated here the reason for cell damage in such cells, and it was the osmotic pressure after freeze concentration. Furthermore, the addition of dimethyl sulfoxide (DMSO) has been reported to improve the cryoprotective effect in such cells: the zwitterion/DMSO aqueous solution shows a higher cryoprotective effect than the commercial cryoprotectant. This study also clarified the mechanisms underlying the improvement in a cryoprotective effect. The addition of cell-permeable DMSO alleviated the osmotic pressure after the freeze concentration. This alleviation was also found to be a key factor for cryopreserving cell spheroids, while there has been no insight into this phenomenon.

Oxidative stress as a marker of inflammation in cataracts

Introduction. Oxidative stress is an important pathogenetic factor of degenerative eye diseases. Oxidative stress can damage tissues, leading to changes in their structure and function, increased vascular permeability, microvascular abnormalities and neovascularization. In turn, these changes can cause damage to the eye; denaturation of the crystalline lens.
 The purpose of the study: according to modern literature, to study the role of oxidative stress and inflammation in the development of cataracts.
 The molecular mechanisms of cell damage under oxidative stress and the pathogenesis of cataracts caused by oxidative stress have been studied.
 Conclusion. Oxidative stress is an important pathogenetic mechanism of degenerative eye diseases. Oxidized phospholipids activate pro-inflammatory molecules and cause inflammation. Oxidative stress in the body is regulated by antioxidant mechanisms. An imbalance of antioxidants affects the lens and causes cataracts. The G/G genotype of SOD1-251 A/G polymorphism may lead to a higher risk of senile cataracts. The content of antioxidants depends on the density of the lens nuclei, on the type of cataract. Non-enzymatic antioxidants have a predominant effect in watery moisture, and enzymatic antioxidants in blood serum in patients with cataracts.

The current state of the paraneoplastic neurological syndromes problem

Paraneoplastic syndromes (PS) are immune-mediated manifestations of a distant oncological process, which is a reaction of autoantibodies against antigens expressed by the tumor. These syndromes are divided into neurological, endocrine, hematological, and dermatological. PS can be diagnosed before or in parallel with tumor detection and often masquerade as neurological or psychiatric disorders. The review discusses the updated 2021 diagnostic criteria, which include revisions to diagnostic levels since 2004, as well as new classifications of antibodies based on the pathogenetic mechanisms of nerve cell damage and their frequency of detection in patients. The phenotypes of high-, medium-, and low-risk paraneoplastic neurological syndromes (PNS) are highlighted, with a special emphasis on the clinical features of high-risk phenotypes. Particular attention is paid to limbic encephalitis, its clinical signs, specific antibodies, instrumental and laboratory studies, and associated oncological diseases. Encephalomyelitis and subacute cerebellar degeneration are also discussed, detailing pathological changes, key antibodies and neoplasia, emphasizing the need for differential diagnosis and immunosuppressive treatment. General features about opsoclonus myoclonus syndrome, its clinical manifestations and causes, as well as Lambert—Eaton myasthenic syndrome are provided, in particular, its association with small cell lung cancer is emphasized, and the features of diagnosis, differential diagnosis with myasthenia gravis and treatment are highlighted. Based on the updated diagnostic criteria, the data analysis will provide clinicians with guidelines for identifying specific phenotypes of PNS and associated antibodies, which are key to improving diagnostic processes and selecting an effective treatment strategy.

Exploring the relationships between physiochemical properties of nanoparticles and cell damage to combat cancer growth using simple periodic table-based descriptors.

A comprehensive knowledge of the physical and chemical properties of nanomaterials (NMs) is necessary to design them effectively for regulated use. Although NMs are utilized in therapeutics, their cytotoxicity has attracted great attention. Nanoscale quantitative structure-property relationship (nano-QSPR) models can help in understanding the relationship between NMs and the biological environment and provide new ways for modeling the structural properties and bio-toxic effects of NMs. The goal of the study is to construct fully validated property-based models to extract relevant features for estimating and influencing the zeta potential and obtaining the toxicity profile regarding cell damage in the treatment of cancer cells. To achieve this, QSPR modeling was first performed with 18 metal oxide (MeOx) NMs to measure their materials properties using periodic table-based descriptors. The features obtained were later applied for zeta potential calculation (imputation for sparse data) for MeOx NMs that lack such information. To further clarify the influence of the zeta potential on cell damage, a QSPR model was developed with 132 MeOx NMs to understand the possible mechanisms of cell damage. The results showed that zeta potential, along with seven other descriptors, had the potential to influence oxidative damage through free radical accumulation, which could lead to changes in the survival rate of cancerous cells. The developed QSPR and quantitative structure-activity relationship models also give hints regarding safer design and toxicity assessment of MeOx NMs.

Iron-induced kidney cell damage: insights into molecular mechanisms and potential diagnostic significance of urinary FTL.

Background: Iron overload can lead to organ and cell injuries. Although the mechanisms of iron-induced cell damage have been extensively studied using various cells, little is known about these processes in kidney cells. Methods: In this study, we first examined the correlation between serum iron levels and kidney function. Subsequently, we investigated the molecular impact of excess iron on kidney cell lines, HEK293T and HK-2. The presence of the upregulated protein was further validated in urine. Results: The results revealed that excess iron caused significant cell death accompanied by morphological changes. Transcriptomic analysis revealed an up-regulation of the ferroptosis pathway during iron treatment. This was confirmed by up-regulation of ferroptosis markers, ferritin light chain (FTL), and prostaglandin-endoperoxide synthase 2 (PTGS2), and down-regulation of acyl-CoA synthetase long-chain family member 4 (ACSL4) and glutathione peroxidase 4 (GPX4) using real-time PCR and Western blotting. In addition, excess iron treatment enhanced protein and lipid oxidation. Supportively, an inverse correlation between urinary FTL protein level and kidney function was observed. Conclusion: These findings suggest that excess iron disrupts cellular homeostasis and affects key proteins involved in kidney cell death. Our study demonstrated that high iron levels caused kidney cell damage. Additionally, urinary FTL might be a useful biomarker to detect kidney damage caused by iron toxicity. Our study also provided insights into the molecular mechanisms of iron-induced kidney injury, discussing several potential targets for future interventions.

Selenium Nanoparticles in Protecting the Brain from Stroke: Possible Signaling and Metabolic Mechanisms.

Strokes rank as the second most common cause of mortality and disability in the human population across the world. Currently, available methods of treating or preventing strokes have significant limitations, primarily the need to use high doses of drugs due to the presence of the blood-brain barrier. In the last decade, increasing attention has been paid to the capabilities of nanotechnology. However, the vast majority of research in this area is focused on the mechanisms of anticancer and antiviral effects of nanoparticles. In our opinion, not enough attention is paid to the neuroprotective mechanisms of nanomaterials. In this review, we attempted to summarize the key molecular mechanisms of brain cell damage during ischemia. We discussed the current literature regarding the use of various nanomaterials for the treatment of strokes. In this review, we examined the features of all known nanomaterials, the possibility of which are currently being studied for the treatment of strokes. In this regard, the positive and negative properties of nanomaterials for the treatment of strokes have been identified. Particular attention in the review was paid to nanoselenium since selenium is a vital microelement and is part of very important and little-studied proteins, e.g., selenoproteins and selenium-containing proteins. An analysis of modern studies of the cytoprotective effects of nanoselenium made it possible to establish the mechanisms of acute and chronic protective effects of selenium nanoparticles. In this review, we aimed to combine all the available information regarding the neuroprotective properties and mechanisms of action of nanoparticles in neurodegenerative processes, especially in cerebral ischemia.

The gut microbiome and primary open angle glaucoma: Evidence for a 'gut-glaucoma' axis?

Glaucoma presents an epidemiological burden as the leading cause of irreversible blindness globally and the most common cause of preventable blindness. While elevated intraocular pressure is the strongest modifiable risk factor, the exact mechanisms of retinal ganglion cell damage leading to progressive vision loss are not entirely understood. Studies of other neurodegenerative diseases show a potential for human gut microbiome dysbiosis to play a pathogenic role. An investigation into whether the microbiome, a potential modifiable risk factor, has significance in glaucoma enables exploration of prophylactic or additive treatments. Elevated population levels of specific bacterial species have been noted in glaucoma patients, particularly Prevotellaceae, Enterobacteriaceae and Escherichia coli, while Megomonas is speculated to be protective. Evidence also points to systemic neuro-inflammation and disruption of autoimmune processes as a result of imbalances in both human and animal models, where heat shock proteins may contribute to pathogenesis. Further research into the influence of gut microbiome on pathogenesis offers a chance to minimise irreversible vision loss in glaucoma.

Mechanisms of E-Cigarette Vape-Induced Epithelial Cell Damage.

E-cigarette use has been reported to affect cell viability, induce DNA damage, and modulate an inflammatory response resulting in negative health consequences. Most studies focus on oral and lung disease associated with e-cigarette use. However, tissue damage can be found in the cardio-vascular system and even the bladder. While the levels of carcinogenic compounds found in e-cigarette aerosols are lower than those in conventional cigarette smoke, the toxicants generated by the heat of the vaping device may include probable human carcinogens. Furthermore, nicotine, although not a carcinogen, can be metabolized to nitrosamines. Nitrosamines are known carcinogens and have been shown to be present in the saliva of e-cig users, demonstrating the health risk of e-cigarette vaping. E-cig vape can induce DNA adducts, promoting oxidative stress and DNA damage and NF-kB-driven inflammation. Together, these processes increase the transcription of pro-inflammatory cytokines. This creates a microenvironment thought to play a key role in tumorigenesis, although it is too early to know the long-term effects of vaping. This review considers different aspects of e-cigarette-induced cellular changes, including the generation of reactive oxygen species, DNA damage, DNA repair, inflammation, and the possible tumorigenic effects.

Zebrafish models of sensorineural hearing loss

Sensorineural hearing loss negatively impacts over 450 million people worldwide. While we know that insults such as ototoxic drugs and noise damage sensory hair cells, our understanding of damage mechanisms is incomplete. Zebrafish are an exciting vertebrate model for research on fundamental mechanisms of hair cell damage. In addition to the inner ear, zebrafish have a lateral line system containing clusters of externally located hair cells. These hair cells are homologous to vertebrate inner ear hair cells and respond similarly to ototoxic damage. Our lab uses the lateral line system to determine the ototoxic potential of COVID-19 therapies; with over 900 medications currently in clinical trials, it is highly likely that a subset of those medications causes mild hearing loss that is not detected in clinical settings. In addition, while ototoxicity is a significant concern for patients exposed to these medications, acoustic damage and age-related hearing loss are far more prevalent in the general population. Our lab developed a zebrafish model of acoustic trauma and showed that noise exposure causes synaptic damage and hair cell loss in the larval lateral line analogous to the damage observed in the mammalian cochlea. Finally, we show that aged adult zebrafish lose both lateral line and inner ear hair cells similar to hair cell loss seen in aging mammals. Collectively, our research demonstrates that zebrafish are a tractable model to understand mechanisms of sensorineural hearing loss and to test therapeutic strategies.

Ahp deficiency-induced redox imbalance leads to metabolic alterations in E.coli

Alkyl hydroperoxide reductase (Ahp) is the primary scavenger of endogenous hydrogen peroxide in Escherichia coli (E. coli). Ahp-deficient strains have been found to have high reactive oxygen species (ROS) levels, sufficient to cause cell damage. However, the exact role and underlying mechanisms of Ahp deficiency-induced cell damage remain largely unknown. Here, the E. coli MG1655 ΔAhp mutant strain was constructed as a model of deficiency to assess its role. The cells of the ΔAhp strain were found to be significantly longer than those of the wild strain, with elevated ROS and hydrogen peroxide (H2O2) levels. Proteome, redox proteome and metabolome analyses were performed to systematically present a global and quantitative profile and delineate the redox signaling and metabolic alterations at the proteome, metabolome, and cysteine oxidation site levels. The multiomics data revealed that Ahp deficiency disrupted the redox balance, activated the OxyR system, upregulated oxidative defense proteins and inhibited the TCA cycle to some extent. Surprisingly, the mutant strain shifted from aerobic respiration to anaerobic respiration and fermentation during the logarithmic phase in the presence of sufficient O2. The acid resistance system was activated to mitigate the effect of excessive acid produced by fermentation. Taken together, the results of this study demonstrated that Ahp deficiency triggered cellular redox imbalance and regulated metabolic pathways to confer resistance to submicromolar intracellular H2O2 levels in E. coli.

T-2 mycotoxin Induces male germ cell apoptosis by ROS-mediated JNK/p38 MAPK pathway

T-2 mycotoxin, a type A trichothecene toxin that, specifically, causes male and female reproductive toxicity. We evaluated T-2 toxin toxicity in testes from neonatal testes after in vitro tissue cultured. Additionally, current study focuses on the molecular mechanism of toxicity and germ cell damage in GC-1 spermatogonial cells. Mouse testicular fragments were subjected to T-2 toxin (0–20 nM) during days 5 of in vitro culture. Testicular germ cell number were reduced and downregulated the expression of corresponding markers depending on the exposure concentration of T-2 toxin; however, Sertoli cell markers and steroidogenic enzyme expression increased when treated with 20 nM T-2 toxin. The cell viability decreased, apoptosis increased, and pro-apoptotic protein expression increased in 5–20 nM T-2 toxin–exposed spermatogonia. Moreover, T-2 toxin generated reactive oxygen species (ROS) and induced mitochondrial dysfunction, indicating that activation of p38 MAPK signaling triggered by ROS is involved in the apoptotic molecular mechanism of T-2 toxin. T-2 toxin induced the phosphorylation of ERK1/2, c-Jun, JNK/SAPK, p38, and p53, and the subsequent inhibition of AKT phosphorylation. The upregulation of genes related to apoptosis and MAPK/JNK signaling was consistently observed in cells exposed to T-2 toxin. These results indicate that T-2 toxin triggers apoptotic cell death in germ cells through the triggering of ROS-mediated JNK/p38-MAPK signaling pathways.

Cytotoxicity and Genotoxicity Evaluation of Zanthoxylum rhoifolium Lam and In Silico Studies of Its Alkaloids.

The alkaloids isolated from Zanthoxylum rhoifolium have demonstrated great pharmacological potential; however, the toxic profiles of these extracts and fractions are still not well elucidated. This study evaluated the toxicity of the ethanol extract (EEZR) and neutral (FNZR) and alkaloid (FAZR) fractions. Chemical characterization was performed by chromatographic methods: thin-layer chromatography (TLC) and high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The cytotoxicity of the samples was evaluated in human hepatocellular carcinoma (HepG2) cells using the cell viability method (MTT) and mutagenicity by the Allium cepa assay (ACA). Alkaloids isolated from the species were selected for toxicity prediction using preADMET and PROTOX. The molecular docking of the topoisomerase II protein (TOPOII) was used to investigate the mechanism of cell damage. In the EEZR, FNZR, and FAZR, the presence of alkaloids was detected in TCL and HPLC-DAD analyses. These samples showed a 50% inhibitory concentration (IC50) greater than 400 μg/mL in HepG2 cells. In ACA, time- and concentration-dependent changes were observed, with a significant reduction in the mitotic index and an increase in chromosomal aberrations for all samples. Nuclear sprouts and a micronucleus of the positive control (PC) were observed at 10 µg/mL and in the FAZR at 30 µg/mL; a chromosomal bridge in FNZR was observed at 105 µg/mL, CP at a concentration of 40 µg/mL, and nuclear bud and mitotic abnormalities in the EEZR were observed at 170 µg/mL. The alkaloids with a benzophenanthridine were selected for the in silico study, as structural alterations demonstrated certain toxic effects. Molecular docking with topo II demonstrated that all alkaloids bind to the protein. In summary, the fractionation of Z. rhoifolium did not interfere with toxicity; it seems that alkaloids with a benzophenanthridine nucleus may be involved in this toxicity.

RED LASER PHOTODYNAMIC THERAPY OF MELANOMA B16 IN AN EXPERIMENTAL MODEL IN VIVO

Introduction: In recent decades, the incidence of melanoma among European population has been steadily increasing. In addition, the age of patients with this pathology is declining - today more than half of patients with melanoma are under 65 years. Melanoma is an aggressive metastatic tumor that is difficult to treat. The tumor is resistant to chemotherapy and radiotherapy. However, the mechanism of photodynamic action differs from the mechanism of cell damage by antitumor drugs or ionizing radiation. Therefore, there is a high probability that with the help of photodynamic therapy it will be possible to overcome the resistance of melanoma cells to damage. Materials and methods: The study was performed on melanoma tumors of B16 mice. The due methylene blue (MB) was used as a photosensitizer through the known affinity of this colorant to the melanin pigment of melanoma cells. The experiments used the radiation of two semiconductor lasers (Fotonika Plus, Cherkasy. Ukraine) with a wavelength of 660 nm, which corresponds to the maximum absorption of methylene blue. Results:The possibility of increasing the anti-melanoma photodynamic activity of MB with the help of a modifier - the natural polysaccharide chitosan was studied. B16 melanoma has been shown to be sensitive to PDT with MB and its sensitivity can be increased by using MB with the natural polysaccharide chitosan, which has immunoadjuvant properties. Conclusion: As a result of the presented research, a variant of PDT of B16 melanoma of mice was developed using MB sensitizer and chitosan immunoadjuvant, which includes intratumoral injection of MB together with chitosan, irradiation of tumors with a red laser with a wavelength of 660 nm, as well as the use of chitosan as an immunomodulatory factor.

Oxidative stress and protection against it in bacteria

Microorganisms are exposed to reactive oxygen species (ROS) that are formed in various ways, in particular, as a result of respiration or other intracellular processes, during metal-catalyzed Fenton reactions, as a result of the action of UV- and X-radiation, under the influence of some antimicrobial drugs, or during the host immune oxidative-burst response against infection agents. In this review, we take a look at the mechanisms of microbial cell damage, including damage of lipids and proteins. Lipid peroxidation (LPO) is one of the main molecular mechanisms involved in oxidative damage to cellular structures. A variety of products are formed during LPO reactions: alkoxyl radicals, peroxyl radicals, hydroperoxides, diene conjugates, carbonyl compounds, aldehyde adducts with biopolymers, alcohols, esters, etc. These products include cytotoxic and highly reactive compounds. Free radical reactions of protein damage occur via hydrogen atom abstraction from α-carbon or SH-, NH2-groups of aminoacids and electron abstraction from nucleophile centers of proteins resulting in the fragmentation of proteins, their denaturation and the formation of amino acid radicals. Bacteria show a significant adaptive potential to the influence of stress agents, including ROS. We summarized the data on bacterial antioxidant protection, ROS redox sensors, and regulators of bacterial cell response to ROS exposure, focusing on the features of anaerobic microorganisms, as their responses to the oxidative damage are the least studied, and many problems remain unsolved. This review contains information about changes in fatty acid composition of lipids of the plasma membrane to maintain the necessary fluidity, and, thus, counteract the effects of various stressing agents, including ROS. The main modifications of the fatty acid composition of lipids important for the regulation of membrane fluidity are described, in particular, via changes in the degree of lipid saturation, cis/trans isomerization, and synthesis of cyclopropane fatty acids.

IFN-γ is Necessary but not Sufficient to mediate Activated CD4+ T cell-induced epithelial cell damage and death

Abstract Bidirectional communication between the intestinal epithelial barrier and the immune cells in the underlying lamina propria is critical to human health. This study investigates the impact of human T cell subtypes on intestinal epithelial cell phenotype and survival. Blood-derived CD4+ or CD8+ T cells were isolated from healthy human participants using negative magnetic separation and co-cultured with healthy human colonic epithelial stem cell spheroids suspended in Matrigel. A subset of T cells was activated by anti-CD3/CD28 cross-linking for 24 h prior to co-culture. Only activated CD4+ T cells (ACD4) caused significant epithelial cell damage and death as measured by histological scoring of brightfield microscopic images and zombie violet+ epithelial cells detected by flow cytometry. The mechanism of cell damage and death was determined to be via soluble mediators, in that conditioned media from ACD4 but not activated CD8+ T cells (ACD8) significantly induced spheroid cell damage and death. A Luminex cytokine multiplex assay revealed that high levels of IFN-γ, IL-17, and TNF-α were produced by ACD4 as compared with ACD8. Neutralizing IFN-γ antibody completely protected spheroids from death induced by ACD4. In contrast, the addition of only IFN-γ protein did not induce spheroid cell death. This finding conflicts with currently published literature that indicates IFN-γ protein is able to induce spheroid cell death for both humans and mice. In addition, ACD8 also secrete IFN-γ, although to a lesser extent than ACD4, yet do not initiate spheroid cell death. These results indicate that there is a unique mixture of immune mediator released by ACD4s that mediate spheroid damage and death. DP1 DA-037997 T32 GM007250