Mechanisms Of Cell Protection Research Articles

GPX4 expression changes in proximal tubule cells highlight the role of ferroptosis in IgAN

As an important mechanism of renal injury, oxidative stress (OS) is inseparable from the occurrence of renal fibrosis and the rapid progression of renal failure. However, the contribution of OS to IgA nephropathy (IgAN), the primary driver of chronic kidney disease remains uncertain. To investigate the effects of OS in IgAN, and identify the mechanisms of cell and tissue injury and protection, single-cell RNA sequencing (scRNA-seq) data and microarray data of IgAN were collected and analyzed. Through gene set variation analysis (GSVA), we identified significant alterations in the activity of multiple OS pathways within the proximal tubule cells (PTCs) of IgAN patients. Subsequent enrichment analysis revealed that the differentially expressed genes associated with OS in PTCs were primarily linked to the process of ferroptosis. Therefore, regulators of ferroptosis were collected to define the ferroptosis activity of PTCs in IgAN, and we found that the activity of suppressing ferroptosis was significantly enhanced. Moreover, being the central controller of ferroptosis, the expression of GPX4 in the PTCs of IgAN is extremely significant, which has been further verified by immunohistochemistry in kidney tissues of IgAN patients. Additionally, the GSVA of microarray data of IgAN indicated that the activity of driving ferroptosis and suppressing ferroptosis in tubulointerstitium were markedly decreased, however, the inhibition of ferroptosis in the tubulointerstitium of IgAN is relatively stronger. These findings demonstrate that ferroptosis inhibition may be a potential mechanism to alleviate OS injury in IgAN, and GPX4 could not only function as a specific marker for PTCs in IgAN but also represent a potential therapeutic target to halt the progression of the disease.

Molecular Mechanisms of Cell Protection Against Injury—The Foundation of Cell Protective Engineering

Abstract Cells can launch self-protective mechanisms against injury, induced by ischemia, mechanical impact, toxins, radiation, or microorganisms (viruses, bacteria, and fungi), and can also recruit other cells to assist in the protective processes. Primary cell protective mechanisms include early-phase discharge of small molecules (adenosine and bradykinin) and subsequent expression and release of cytokines, growth factors, and anti-reactive oxygen species enzymes from the injured cells as well as activated/recruited cells. These protective factors can act on cognate signaling pathways in the injured cells to support cell survival and prevent cell death. However, these cell protective mechanisms are not optimal in the timing of activation and the level of effectiveness—often occurring after cell death with insufficient activity. Thus, it is necessary to develop and utilize cell protective engineering strategies to activate promptly protective factors to sufficient levels, thereby optimizing cell protective processes. This article reviews the molecular mechanisms of cell protection in injury by using experimental myocardial ischemia as a model and potential engineering strategies for optimizing cell protective processes.

Protective Effect of Marine Peptide from Netunea arthritica cumingii Against Gentamicin-Induced Hair Cell Damage in Zebrafish.

Auditory hair cell damage induced by aminoglycoside antibiotics (AmAn) leads to hearing loss, which has a serious effect on people's mental and physical health. This ototoxicity is thought to be related with the excessive accumulation of reactive oxygen species (ROS) in hair cells. However, therapeutic agents that protect hair cells are limited. Marine peptides have been shown to have excellent potential applications in disease prevention and treatment. Therefore, this study investigated the protective effects of an active peptide from Neptunea arthritica cumingii against AmAn-induced hair cell damage using the model of hair cell damage zebrafish. We identified the number, ultrastructure, and function of hair cells using fluorescence probes and scanning electron microscopy. The uptake of AmAn, ROS level, mitochondrial permeability transition pore, and apoptosis in hair cells were also tested by fluorescence labeling and TUNEL assay. The molecular mechanism for hair cell protection exerted by the peptide was detected by a real-time quantitative PCR assay. The results indicated that the peptide suppressed the uptake of AmAn but did not damage the function of hair cells mediating hearing. It also prevented ROS accumulation, decreased the occurrence of apoptosis, and rescued the abnormal opening and expressions of mitochondrial permeability transition pore and genes related to antioxidants. The peptide may be an effective therapeutic agent for AmAn-induced ototoxicity. In the future, we plan to use mammalian models to further investigate the otoprotective effect of the peptide.

PARP-1 negatively regulates nucleolar protein pool and mitochondrial activity: a cell protective mechanism

BackgroundPoly(ADP-ribose) polymerase-1 (PARP-1) is a pan nuclear protein that utilizes NAD+ as a substrate for poly(ADP-ribosyl)ation reaction (PARylation), resulting in both auto-modification and the modification of its accepter proteins. Earlier reports suggested that several nucleolar proteins interact and colocalize with PARP-1, leading to their PARylation. However, whether PARP-1 has any role in nucleolar biogenesis and the functional relevance of such a role is still obscure.ResultsUsing PARP-1 depleted cells, we investigated the function of PARP-1 in maintaining the nucleolar morphology and protein levels under normal physiological conditions. Our results revealed that several nucleolar proteins like nucleolin, fibrillarin, and nucleophosmin get up-regulated when PARP-1 is depleted. Additionally, in line with the higher accumulation of nucleolin, stably depleted PARP-1 cells show lower activation of caspase-3, lesser annexin-V staining, and reduced accumulation of AIF in the nucleus upon induction of oxidative stress. Concurrently, PARP-1 silenced cells showed higher mitochondrial oxidative phosphorylation and more fragmented and intermediate mitochondria than the parental counterpart, suggesting higher metabolic activity for better survival.ConclusionBased on our findings, we demonstrate that PARP-1 may have a role in regulating nucleolar protein levels and mitochondrial activity, thus maintaining the homeostasis between cell protective and cell death pathways, and such cell-protective mechanism could be implicated as the priming state of a pre-cancerous condition or tumour dormancy.

β-aminoisobutyric acid ameliorated type 1 diabetes-induced germ cell toxicity in rat: Studies on the role of oxidative stress and IGF-1/AMPK/SIRT-1 signaling pathway

Diabetes mellitus is known as the “epidemic of the century” due to its global prevalence. Several pre-clinical and clinical studies have shown that male germ cell toxicity is one of the major consequences of diabetes mellitus. Although β-aminoisobutyric acid (BAIBA) has been shown to be advantageous in the diabetic nephropathy and cardiomyopathy, its specific role in the diabetes-induced testicular toxicity remains unknown. In this study, an attempt was made to elucidate the molecular mechanisms of BAIBA-mediated germ cell protection in diabetic rats. Adult male Sprague-dawley rats were subjected to either no treatment (control) or BAIBA (100 mg/kg; BAIBA control) or Streptozotocin (50 mg/kg; diabetic control) or low (25 mg/kg), medium (50 mg/kg) and high (100 mg/kg) doses of BAIBA in diabetic conditions. Significant alterations in sperm related parameters, oxidative stress and apoptotic biomarkers, pancreatic and testicular histology, DNA damage and changes in expression of proteins in testes were found in the diabetic rats. 100 mg/kg of BAIBA significantly reduced the elevated blood glucose levels (P ≤ 0.05), increased body weight (P ≤ 0.01 in the 4th week), lowered malondialdehyde (P ≤ 0.05) and nitrite levels (P ≤ 0.01), elevated testosterone (P ≤ 0.05) and FSH levels (P ≤ 0.05), increased sperm count and motility (P ≤ 0.01), decreased testicular DNA damage (P ≤ 0.001), improved histological features of pancreas and testes, decreased TUNEL positive cells (P ≤ 0.01), decreased RAGE (P ≤ 0.01) and Bax (P ≤ 0.05) expressions and increased SIRT1 (P ≤ 0.05) and Atg 12 (P ≤ 0.05) expressions in the testes. 50 mg/kg of BAIBA partially restored the above-mentioned parameters whereas 25 mg/kg of BAIBA was found to be insignificant in counteracting the toxicity. It is interesting to note that BAIBA protects male germ cell damage in diabetic rats by regulating the IGF-1/AMPK/SIRT-1 signaling pathway.

Mst1-mediated phosphorylation of FoxO1 and C/EBP-β stimulates cell-protective mechanisms in cardiomyocytes

The molecular mechanisms by which FoxO transcription factors mediate diametrically opposite cellular responses, namely death and survival, remain unknown. Here we show that Mst1 phosphorylates FoxO1 Ser209/Ser215/Ser218/Thr228/Ser232/Ser243, thereby inhibiting FoxO1-mediated transcription of proapoptotic genes. On the other hand, Mst1 increases FoxO1-C/EBP-β interaction and activates C/EBP-β by phosphorylating it at Thr299, thereby promoting transcription of prosurvival genes. Myocardial ischemia/reperfusion injury is larger in cardiac-specific FoxO1 knockout mice than in control mice. However, the concurrent presence of a C/EBP-β T299E phospho-mimetic mutation reduces infarct size in cardiac-specific FoxO1 knockout mice. The C/EBP-β phospho-mimetic mutant exhibits greater binding to the promoter of prosurvival genes than wild type C/EBP-β. In conclusion, phosphorylation of FoxO1 by Mst1 inhibits binding of FoxO1 to pro-apoptotic gene promoters but enhances its binding to C/EBP-β, phosphorylation of C/EBP-β, and transcription of prosurvival genes, which stimulate protective mechanisms in the heart.

Modeling of Intracellular Taurine Levels Associated with Ovarian Cancer Reveals Activation of p53, ERK, mTOR and DNA-Damage-Sensing-Dependent Cell Protection.

Taurine, a non-proteogenic amino acid and commonly used nutritional supplement, can protect various tissues from degeneration associated with the action of the DNA-damaging chemotherapeutic agent cisplatin. Whether and how taurine protects human ovarian cancer (OC) cells from DNA damage caused by cisplatin is not well understood. We found that OC ascites-derived cells contained significantly more intracellular taurine than cell culture-modeled OC. In culture, elevation of intracellular taurine concentration to OC ascites-cell-associated levels suppressed proliferation of various OC cell lines and patient-derived organoids, reduced glycolysis, and induced cell protection from cisplatin. Taurine cell protection was associated with decreased DNA damage in response to cisplatin. A combination of RNA sequencing, reverse-phase protein arrays, live-cell microscopy, flow cytometry, and biochemical validation experiments provided evidence for taurine-mediated induction of mutant or wild-type p53 binding to DNA, activation of p53 effectors involved in negative regulation of the cell cycle (p21), and glycolysis (TIGAR). Paradoxically, taurine's suppression of cell proliferation was associated with activation of pro-mitogenic signal transduction including ERK, mTOR, and increased mRNA expression of major DNA damage-sensing molecules such as DNAPK, ATM and ATR. While inhibition of ERK or p53 did not interfere with taurine's ability to protect cells from cisplatin, suppression of mTOR with Torin2, a clinically relevant inhibitor that also targets DNAPK and ATM/ATR, broke taurine's cell protection. Our studies implicate that elevation of intracellular taurine could suppress cell growth and metabolism, and activate cell protective mechanisms involving mTOR and DNA damage-sensing signal transduction.

HPV replicative cycle and role of viral proteins in lesion progression

Human papillomaviruses are DNA viruses that primarily infect the stratified squamous epithelium of the genital tract mucosa. Some of these viruses are strongly associated with cervical cancer. They are sexually transmitted agents that are highly prevalent around the world. Most infections heal spontaneously, in approximately 18 to 24 months, but in some individuals, the virus persists in a latent, asymptomatic form or a productive form, causing cervical intraepithelial lesions that may progress to result in invasive cervical cancer. During productive infection, the virus executes a complex interaction program with the host cell dependent on differentiation and, through its proteins, nullifies the host cell's protective mechanisms against malignant transformation and suppresses the host's immune responses. Initial lesions may spontaneously revert, but those that reach a certain stage, if not treated, progress to malignant forms. In this review, we present some advances in the biology of HPV infection and the role of its proteins in the interaction with the host cell and its consequences.

RAGE induces physiological activation of NADPH oxidase in neurons and astrocytes and neuroprotection.

The transmembrane receptor for advanced glycation end products (RAGE) is a signaling receptor for many damage- and pathogen-associated molecules. Activation of RAGE is associated with inflammation and an increase in reactive oxygen species (ROS) production. Although several sources of ROS have been previously suggested, how RAGE induces ROS production is still unclear, considering the multiple targets of pathogen-associated molecules. Here, using acute brain slices and primary co-culture of cortical neurons and astrocytes, we investigated the effects of a range of synthetic peptides corresponding to the fragments of the RAGE V-domain on redoxsignaling. We found that the synthetic fragment (60-76) of the RAGE V-domain induces activation of ROS production in astrocytes and neurons from the primary co-culture and acute brain slices. This effect occurred through activation of RAGE and could be blocked by a RAGE inhibitor. Activation of RAGE by the synthetic fragment stimulates ROS production in NADPH oxidase (NOX). This RAGE-induced NOX activation produced only minor decreases in glutathione levels and increased the rate of lipid peroxidation, although it also reduced basal and β-amyloid induced cell death in neurons and astrocytes. Thus, specific activation of RAGE induces redox signaling through NOX, which can be a part of a cell protective mechanism.

Docosahexanoic Acid Attenuates Palmitate-Induced Apoptosis by Autophagy Upregulation via GPR120/mTOR Axis in Insulin-Secreting Cells.

Polyunsaturated fatty acids (PUFAs) reportedly have protective effects on pancreatic β-cells; however, the underlying mechanisms are unknown. To investigate the cellular mechanism of PUFA-induced cell protection, mouse insulinoma 6 (MIN6) cells were cultured with palmitic acid (PA) and/or docosahexaenoic acid (DHA), and alterations in cellular signaling and apoptosis were examined. DHA treatment remarkably repressed caspase-3 cleavage and terminal deoxynucleotidyl transferase-mediated UTP nick end labeling (TUNEL)-positive red dot signals in PA-treated MIN6 cells, with upregulation of autophagy, an increase in microtubule- associated protein 1-light chain 3 (LC3)-II, autophagy-related 5 (Atg5), and decreased p62. Upstream factors involved in autophagy regulation (Beclin-1, unc51 like autophagy activating kinase 1 [ULK1], phosphorylated mammalian target of rapamycin [mTOR], and protein kinase B) were also altered by DHA treatment. DHA specifically induced phosphorylation on S2448 in mTOR; however, phosphorylation on S2481 decreased. The role of G protein-coupled receptor 120 (GPR120) in the effect of DHA was demonstrated using a GPR120 agonist and antagonist. Additional treatment with AH7614, a GPR120 antagonist, significantly attenuated DHA-induced autophagy and protection. Taken together, DHA-induced autophagy activation with protection against PA-induced apoptosis mediated by the GPR120/mTOR axis. These findings indicate that DHA has therapeutic effects on PA-induced pancreatic β-cells, and that the cellular mechanism of β-cell protection by DHA may be a new research target with potential pharmacotherapeutic implications in β-cell protection.

Dopamine pre-treatment impairs the anti-cancer effect of integrated stress response- and TRAIL pathway-inducing ONC201, ONC206 and ONC212 imipridones in pancreatic, colorectal cancer but not DMG cells.

ONC201 (originally discovered as TRAIL-Inducing Compound #10 or TIC10) and analogue ONC206 have been found to induce an integrated stress response with suggested primary targets and mechanisms involving targeting mitochondrial protein ClpP and antagonism of dopamine receptors D2/3 (DRD2/3). We hypothesized that dopamine, the agonist of DRD2, may counteract ONC201 or ONC206 for DRD2/3 and impair the anti-cancer effect of ONC201 or ONC206, thus protect the tumor cells from the cytotoxic effect of ONC201 or ONC206. We therefore pre-treated cancer cells from different tissue origins including breast cancer, pancreatic cancer, colorectal cancer, and diffuse midline glioma (DMG) with dopamine, followed by treatment of ONC201, ONC206 or ONC212. We observed that 48 hours of pre-treatment with dopamine impaired the cell viability suppression effect of ONC201, ONC206 and ONC212 in pancreatic cancer cells and colorectal cancer cells. We pre-treated multiple cancer cell lines with dopamine for one week followed by ONC201, ONC206, or ONC212 treatment and performed colony assays. Pre-treatment with dopamine impaired the anti-cancer effect of ONC201 or ONC206 in pancreatic cancer and colorectal cancer. Impairment of ONC212 effect by pre-treatment with dopamine was also seen in colony assay for colorectal cancer, but not in pancreatic cancer cells by colony assay. No protection from killing by imipridones was observed with DRD2 agonist sumanirole in tumor cells, or with brain tumor cell lines pretreated with dopamine. Immunoblotting was conducted to investigate whether dopamine pre-treatment impacts signaling pathways reported to be affected by ONC201. The dopamine pre-treatment did not impact changes in ATF4, CHOP, DR5 and ClpX which were reported to be affected by ONC201. The mechanism of impairment of ONC201/206/212 effect caused by dopamine pre-treatment appears to involve upregulation of anti-apoptotic p-Bad, XIAP, FLIP and pAkt. Our results shed light on mechanisms of cancer cell protection by dopamine after imipridone treatment, heterogeneity among different tumor cell types, and suggest that effects of dopamine adaptation on tumor cells may impact on cell survival pathways in ways that may or may not depend on expression of dopamine receptors.

Irradiation of human oral mucosa by 233 nm far UV-C LEDs for the safe inactivation of nosocomial pathogens

The inactivation of multi resistant pathogens is an important clinical need. One approach is UV-C irradiation, which was previously not possible in vivo due to cytotoxicity. Recently, far UV-C irradiation at λ < 240 nm was successfully used on skin with negligible damage. A potential application site is the nasal vestibule, where MRSA accumulates and cannot be treated using antiseptics. We irradiated 3D mucosa models and excised human mucosa with 222 and 233 nm far UV-C in comparison to 254 nm and broadband UV-B. Eradication efficiency was evaluated by counting colony forming units; irritation potential was evaluated by hen’s egg-chorioallantoic membrane assay and trans epithelial electrical resistance; cell viability was assessed by MTT. DNA damage and cell protective mechanisms were evaluated immunohistopathologically. On mucosa models, MRSA reduced by ≈ 5 log10 for 60 mJ/cm2 irradiation at 233 nm. A slightly increased cell viability was observed after 24 h. Lower doses showed lower irritation potential than the positive controls or commercial mouthwash, while 80 mJ/cm2 had strong irritation potential. DNA damage occurred only superficially and decreased after 24 h. On excised human mucosa, < 10% of keratinocytes were affected after 150 mJ/cm2 222 nm or 60 mJ/cm2 233 nm.

Mitophagy As a Novel Cell-Protective Mechanism Against Mitochondrial Ferroptosis in Acute Myeloid Leukemia

Background:Resistance to apoptosis poses a major clinical challenge in the therapy of acute myeloid leukemia (AML), leading to dismal clinical outcomes. Ferroptosis, another mode of regulated cell death that could bypass apoptosis resistance, has recently been investigaed for its therapeutic potential in therapy-resistant cancers. Meanwhile, accumulating evidence suggests that the regulation of ferroptosis is highly context-dependent and thus varies among cancer types. Hence, it is crucial to elucidate unique regulatory mechanisms in each tumor type for developing a therapeutic strategy. We recently found cell survival dependence of AML cells on GPX4, a major negative regulator of ferroptosis, and unique mechanistic involvement of mitochondria in AML ferroptosis. Results: We demonstrate that a selective GPX4 inhibitor ML210 as well as GPX4 knockdown induces ferroptosis, defined by iron- and lipid-peroxidation-dependence, in AML cell lines and primary AML samples, regardless of venetoclax resistance or genetic features including TP53 mutations. The cell sensitivity was negatively correlated with GPX4 protein expressions (i.e., the lower the expression, the higher the sensitivity). Normal bone marrow cells exhibited higher GPX4 levels compared to AML cells and showed significantly less sensitivity to ML210 treatment, suggesting a potential therapeutic window for GPX4 inhibition. Anti-leukemia effects of GPX4 knockdown were also observed in vivo, leading to survival prolongation in AML xenografted mice. Importantly, ferroptosis induction in AML cells is accompanied with and highly dependent on mitochondrial lipid peroxidation. 4-Hydroxynonenal (4-HNE) is one of the most biologically active products of lipid peroxidation, which is known to form adducts with certain amino acid residues of proteins to induce protein aggregates in the cytosol. We thus hypothesized that mitochondrial lipid peroxides induce mitochondrial protein aggregation in AML cell ferroptosis. Intriguingly, confocal microscopy revealed mitochondrial protein aggregation as evidenced by the co-localization of TOMM20 and protein aggregates detected by the PROTEOSTAT assay (Figure 1). Given that mitochondrial stress induced by protein aggregation reportedly induces mitophagy as a cellular stress response, we presumed that AML cells under the stress of ferroptosis may also show increased mitophagy. Indeed, GPX4 inhibition induced mitophagy, particularly in persistent AML cells, which was detected by the Mitophagy dye as mitochondrial acidification when fused with lysosomes, suggesting that mitophagy is a cell-protective response against ferroptosis as a quality control mechanism of malfunctioning mitochondria with lipid peroxidation and protein aggregation. Indeed, among persistent AML cells exposed to GPX4 inhibition, cells with more mitophagy were more resistant to further treatment with ML210 compared to those with less mitophagy. Consistently, an analogue of the ceramide-mediated mitophagy inducer LCL-461 (Dany, et al. 2016 Blood) suppressed GPX4 inhibition-induced ferroptosis in AML cells. On the other hand, inhibition of ULK1-dependent mitophagy through ULK1 knockout or the ULK1 inhibitor SBI0206965 (Bhattacharya, et al. 2021 Molecular Cancer Research) synergistically enhanced the anti-leukemia effects of GPX4 inhibition (Figure 2), suggesting a more effective therapeutic potential in ferroptosis in AML. Conclusion:Our study revealed that ferroptosis in AML cells causes mitochondrial protein aggregation and that mitophagy is induced in ferroptosis-persistent AML cells as a cell-protective mechanism against ferroptosis. This provides novel mechanistic insights into mitochondrial ferroptosis in AML, suggesting the therapeutic potential of co-targeting mitophagy in ferroptosis-based therapy. Further studies are in progress to elucidate the molecular mechanisms involved as well as the in vivo efficacy and safety of the combinatorial treatment.

"Possible Existence of the Relict Mechanism of Cell Protection During Division"

"Possible Existence of the Relict Mechanism of Cell Protection During Division"

Preconditioning-induced retinal protection appears promising: a review

Like human and animal myocardium and cerebral nervous tissue, the human and animal retina has powerful intrinsic adaptive mechanisms which can improve cell protection under adverse conditions. These endogenous protective mechanisms are capable of improving the resistance of retinal cells to adverse factors and can be triggered by brief episodes of different subthreshold stimuli (ischemia, photobiomodulation, hypothermia, etc.) preceding a subsequent more sustained injury, a process which is called preconditioning. Results of years of laboratory and clinical studies have demonstrated amazing cardiac protection and cerebral protection opportunities from preconditioning. Although the results of in vivo preclinical studies of retinal conditioning are promising, the benefits from the found effects of preconditioning on the protection of the human retina are still to be assessed. The overview presented highlights some aspects of the research and use of protective effects of preconditioning in various fields of medicine. The results of laboratory studies of endogenous mechanisms of retinal cell protection are discussed herein, along with our recommendations for prospective areas of future use of the effects in cinical ophthalmology for retinal protection.

Validation of a new model of selective antegrade cerebral perfusion with circulatory arrest in rats.

Selective antegrade cerebral perfusion (SACP) is adopted as an alternative to deep hypothermic circulatory arrest (DHCA) during aortic arch surgery. However, there is still no preclinical evidence to support the use of SACP associated with moderate hypothermia (28-30°C) instead of DHCA (18-20°C). The present study aims to develop a reliable and reproducible preclinical model of cardiopulmonary bypass (CPB) with SACP applicable for assessing the best temperature management. A central cannulation through the right jugular vein and the left carotid artery was performed, and CPB was instituted.Animals were randomized into two groups: normothermic circulatory arrest without or with cerebral perfusion (NCA vs SACP). EEG monitoring was maintained during CPB. After 10min of circulatory arrest, rats underwent 60min of reperfusion. After that, animals were sacrificed, and brains were collected for histology and molecular biology analysis. Power spectral analysis of the EEG signal showed decreased activity in both cortical regions and lateral thalamus in all rats during the circulatory arrest. Only SACP determined complete recovery of brain activity and higher power spectral signal compared to NCA (p < 0.05). Histological damage scores and western blot analysis of inflammatory and apoptotic proteins like caspase-3 and Poly-ADP ribose polymerase (PARP) were significantly lower in SACP compared to NCA. Vascular endothelial growth factor (VEGF) and RNA binding protein 3 (RBM3) involved in cell-protection mechanisms were higher in SACP, showing better neuroprotection (p < 0.05). SACP by cannulation of the left carotid artery guarantees good perfusion of the whole brain in this rat model of CPB with circulatory arrest. The present model of SACP is reliable, repeatable, and not expensive, and it could be used in the future to achieve preclinical evidence for the best temperature management and to define the best cerebral protection strategy during circulatory arrest.

Expression profile of the free radicals metabolism and antioxidant genes in chronic obstructive lung disease

Chronic obstructive pulmonary disease (COPD) is a multifactorial heterogeneous chronic inflammatory disease of the respiratory system. Oxidative stress plays a central role in the pathophysiology of COPD. The goal of the study is the identification of new molecular markers of COPD based on the analysis of the expression profile of genes involved to oxidative stress response and antioxidant protection in peripheral blood mononuclear cells. Methods. To identify differential gene expression in COPD we performed expression profiling of 84 oxidative stress response and antioxidant protection genes in peripheral blood mononuclear cells samples from COPD (N=10 with frequent exacerbation emphysema and bronchitis phenotype, N=10 rare exacerbation emphysema phenotype and N=10 smoking controls). RNA was isolated from PBMCs, and gene expression was assessed using RT2 Profiler PCR Arrays « Human Oxidative Stress Plus PCR Array» (Qiagen). Results. Significant changes were revealed in the expression profile of several genes in frequent exacerbation emphysema and bronchitis phenotype COPD phenotype: decreased expression of BNIP3, GCLC, PRNP, TTN, HSP90AA1 gene; and increased expression of FTH1, PRDX3, SOD2 genes. In the group of COPD patients with rare exacerbation emphysema phenotype, an increase in the transcriptional activity of most genes that play a key role in the mechanisms of cell protection from free radical damage was found: FTH1, PRDX3, SOD2, PTGR1,GPX4, GSR, PTGS1, HSPA1A, NCF1 и NCF2, PRDX5, SIRT2, SQSTM1, SRXN1, TXNRD2, LHPP. We confirmed the assumption that the blood cell transcriptome reflects the pathogenesis and systemic nature of COPD and can be considered as a source of information for assessing the severity of the disease, monitoring the effectiveness of therapy, and searching for new non-invasive biomarkers of the disease and its various phenotypes.

Chemical Genetics Screen of EVP4593 Sensitivity in Budding Yeast Identifies Effects on Mitochondrial Structure and Function.

Mitochondria are essential eukaryotic organelles. Mitochondrial dysfunction can lead to mitochondrial myopathies and may contribute to neurodegenerative diseases, cancer, and diabetes. EVP4593, a 6-aminoquinazoline derivative with therapeutic potential, has been shown to inhibit NADH-ubiquinone oxidoreductase (Complex I) of the mitochondrial electron transport chain, causing the release of reactive oxygen species (ROS) and a reduction in ATP synthesis. In isolated mitochondria, EVP4593 inhibits respiration in the nanomolar range (IC 50 = 14-25 nM). However, other EVP4593-specific effects on biological processes have also been described. Consistent with an effect on mitochondrial function in budding yeast, we find that EVP4593 [>25µM] induces a pronounced growth defect when wildtype cells are grown on a non-fermentable carbon source. This sensitivity to EVP4593 is exacerbated by deletion of PDR5 , an ABC transporter that confers multidrug resistance. To better understand the cellular pathways and processes affected by EVP4593, we conducted a genome-wide chemical genetics screen of the yeast knockout collection. The objective was to identify yeast gene deletion strains that exhibit growth defects when subjected to a sublethal concentration of EVP4593 [15µM]. Our screen identified 21 yeast genes that are required for resistance to 15µM EVP4593 in glycerol-containing media. The genes identified in our screen are functionally involved in several distinct categories including mitochondrial structure and function, translational regulation and nutritional sensing, cellular stress response and detoxification. Additionally, we identified cellular phenotypes associated with the exposure to EVP4593, including changes in mitochondrial structure. In conclusion, our study represents the first genome-wide screen in yeast to identify the genetic pathways and cell-protective mechanisms involved in EVP4593 resistance and reveals that this small molecule inhibitor affects both mitochondrial structure and function.

G protein signaling and metabolic pathways as evolutionarily conserved mechanisms to combat calcium deficiency.

Calcium (Ca) deficiency causes necrotic symptoms of foliar edges known as tipburn; however, the underlying cellular mechanisms have been poorly understood due to the lack of an ideal plant model and research platform. Using a phenotyping system that quantitates growth and tipburn traits in the model bryophyte Marchantia polymorpha, we evaluated metabolic compounds and the Gβ-null mutant (gpb1) that modulate the occurrence and expansion of the tipburn. Transcriptomic comparisons between wild-type and gpb1 plants revealed the phenylalanine/phenylpropanoid biosynthesis pathway and reactive oxygen species (ROS) important for Ca deficiency responses. gpb1 plants reduced ROS production possibly through transcriptomic regulations of class III peroxidases and induced the expression of phenylpropanoid pathway enzymes without changing downstream lignin contents. Supplementation of intermediate metabolites and chemical inhibitors further confirmed the cell-protective mechanisms of the phenylpropanoid and ROS pathways. Marchantia polymorpha, Arabidopsis thaliana, and Lactuca sativa showed comparable transcriptomic changes where genes related to phenylpropanoid and ROS pathways were enriched in response to Ca deficiency. In conclusion, our study demonstrated unresolved signaling and metabolic pathways of Ca deficiency response. The phenotyping platform can speed up the discovery of chemical andgenetic pathways, which could be widely conserved between M.polymorpha and angiosperms.

Pesticide responses of Arctic and temperate microalgae differ in relation to ecophysiological characteristics

Polar ecosystems play an important role in global primary production. Microalgae have adaptations that enable them to live under low temperature environments where irradiance and day length change drastically. Their adaptations, leading to different ecophysiological characteristics relative to temperate species, could also alter their sensitivity to pollutants such as pesticides. This study's objective was to understand how different ecophysiological characteristics influence the response of Arctic phytoplankton to pesticides in relation to the responses of their temperate counterparts. Ecophysiological endpoints were related to growth, cell biovolume, pigment content, photosynthetic activity, photoprotective mechanisms (NPQ, antioxidant enzyme activities), and reactive oxygen species (ROS) content. The Arctic species Micromonas polaris was more resistant to atrazine and simazine than its temperate counterpart Micromonas bravo. However, the other Arctic species Chaetoceros neogracilis was more sensitive to these herbicides than its temperate counterpart Chaetoceros neogracile. With respect to two other pesticide toxicity, both temperate microalgae were more sensitive to trifluralin, while Arctic microalgae were more sensitive to chlorpyrifos (insecticide). All differences could be ascribed to differences in the eco-physiological features of the two microalgal groups, which can be explained by cell size, pigment content, ROS content and protective mechanisms (NPQ and antioxidant enzymes).