Carbonyl Stress Research Articles

Stability and Antiglycoxidant Potential of Bilberry Anthocyanins in Simulated Gastrointestinal Tract Model.

Anthocyanins from Vaccinium myrtillus fruits have been reported in vitro to exert potent radical scavenging and antiglycation activities. However, the physiological relevance of such properties remains unclear given the potential susceptibility of anthocyanin derivatives to digestive conditions. A simulated gastrointestinal tract model was thus implemented to assess the impact of gastric and intestinal phases on the chemical integrity of bilberry anthocyanins and their antiglycoxidant effects. Results demonstrated that the investigated activities as well as total and individual anthocyanin contents were marginally affected by gastric conditions. By contrast, with recoveries ranging from 16.1 to 41.2%, bilberry anthocyanins were shown to be highly sensitive to the intestinal phase. Of major interest, a much better preservation was observed for radical scavenging and antiglycation activities as attested by recovery rates ranging from 79.1 to 86.7%. Consistently with previous observations, the present study confirms the moderate bioaccessibility of anthocyanin constituents. It does however provide valuable information supporting the persistence of substantial radical scavenging and antiglycation activities at each step of the digestion process. Taken together, these data indicate that digestive conditions might not abolish the potential positive effects of bilberry consumption on both oxidative and carbonyl stresses.

Interaction between magnesium and methylglyoxal in diabetic polyneuropathy and neuronal models

ObjectiveThe lack of effective treatments against diabetic sensorimotor polyneuropathy demands the search for new strategies to combat or prevent the condition. Because reduced magnesium and increased methylglyoxal levels have been implicated in the development of both type 2 diabetes and neuropathic pain, we aimed to assess the putative interplay of both molecules with diabetic sensorimotor polyneuropathy. MethodsIn a cross-sectional study, serum magnesium and plasma methylglyoxal levels were measured in recently diagnosed type 2 diabetes patients with (n = 51) and without (n = 184) diabetic sensorimotor polyneuropathy from the German Diabetes Study baseline cohort. Peripheral nerve function was assessed using nerve conduction velocity and quantitative sensory testing. Human neuroblastoma cells (SH-SY5Y) and mouse dorsal root ganglia cells were used to characterize the neurotoxic effect of methylglyoxal and/or neuroprotective effect of magnesium. ResultsHere, we demonstrate that serum magnesium concentration was reduced in recently diagnosed type 2 diabetes patients with diabetic sensorimotor polyneuropathy and inversely associated with plasma methylglyoxal concentration. Magnesium, methylglyoxal, and, importantly, their interaction were strongly interrelated with methylglyoxal-dependent nerve dysfunction and were predictive of changes in nerve function. Magnesium supplementation prevented methylglyoxal neurotoxicity in differentiated SH-SY5Y neuron-like cells due to reduction of intracellular methylglyoxal formation, while supplementation with the divalent cations zinc and manganese had no effect on methylglyoxal neurotoxicity. Furthermore, the downregulation of mitochondrial activity in mouse dorsal root ganglia cells and consequently the enrichment of triosephosphates, the primary source of methylglyoxal, resulted in neurite degeneration, which was completely prevented through magnesium supplementation. ConclusionsThese multifaceted findings reveal a novel putative pathophysiological pathway of hypomagnesemia-induced carbonyl stress leading to neuronal damage and merit further investigations not only for diabetic sensorimotor polyneuropathy but also other neurodegenerative diseases associated with magnesium deficiency and impaired energy metabolism.

Role of pleural fluid-serum protein carbonyl gradient in differentiating exudative and transudative effusions

Background: Pleural effusions often cause a diagnostic dilemma. The first step in the evaluation of pleural effusions is the distinction between exudates and transudates.
 Aims and Objectives: The current study was designed to distinguish these two broad subgroups of pleural effusions, based on the protein carbonyl gradient between pleural fluid and serum.
 Materials and Methods: Forty-four exudative and thirty-six transudative pleural effusion cases based on clinical findings and evaluation by Light’s criteria were selected. Protein carbonyl was measured by established photometric method using dinitrophenylhydrazine (DNPH) method in pleural fluid and serum of all the cases.
 Results: Oxidative stress, estimated by the protein carbonyl gradient between pleural fluid and serum, was found to be higher in exudates when compared to transudates. No significant difference was existent between exudates of different aetiology. However, the gradient was higher in exudates from males compared to females. No such difference was found among transudates.
 Conclusions: Carbonyl stress being a simple easily measurable biochemical parameter, pleural fluid to serum protein carbonyl gradient may serve as a useful tool for differentiating pleural effusions based on pathogenesis.

New lipophenols prevent carbonyl and oxidative stresses involved in macular degeneration

Dry age-related macular degeneration and Stargardt disease undergo a known toxic mechanism caused by carbonyl and oxidative stresses (COS). This is responsible for accumulation in the retinal pigment epithelium (RPE) of A2E, a main toxic pyridinium bis-retinoid lipofuscin component. Previous studies have shown that carbonyl stress in retinal cells could be reduced by an alkyl-phloroglucinol-DHA conjugate (lipophenol). Here, we performed a rational design of different families of lipophenols to conserve anti-carbonyl stress activities and improve antioxidant properties. Five synthetic pathways leading to alkyl-(poly)phenol derivatives, with phloroglucinol, resveratrol, catechin and quercetin as the main backbone, linked to poly-unsaturated fatty acid, are presented. These lipophenols were evaluated in ARPE-19 cell line for their anti-COS properties and a structure-activity relationship study is proposed. Protection of ARPE-19 cells against A2E toxicity was assessed for the four best candidates. Finally, interesting anti-COS properties of the most promising quercetin lipophenol were confirmed in primary RPE cells.

The Effect of Iodine-Containing Nano-Micelles, FS-1, on Antibiotic Resistance, Gene Expression and Epigenetic Modifications in the Genome of Multidrug Resistant MRSA Strain Staphylococcus aureus ATCC BAA-39.

Application of supplementary drugs which increase susceptibility of pathogenic bacteria to antibiotics is a promising yet unexplored approach to overcome the global problem of multidrug-resistant infections. The discovery of a new drug, an iodine-containing nano-molecular complex FS-1, which has proven to improve susceptibility to antibiotics in various pathogens, including MRSA strain Staphylococcus aureus ATCC BAA-39TM, allowed studying this phenomenon. Chromosomal DNA and total RNA samples extracted from the FS-1 treated strain (FS) and from the negative control (NC) cultures were sequenced by PacBio SMRT and Ion Torrent technologies, respectively. PacBio DNA reads were used to assemble chromosomal DNA of the NC and FS variants of S. aureus BAA-39 and to perform profiling of epigenetically modified nucleotides. Results of transcriptional profiling, variant calling and detection of epigenetic modifications in the FS variant were compared to the NC variant. Additionally, the genetic alterations caused by the treatment of S. aureus BAA-39 with FS-1 were compared to the results of a similar experiment conducted with another model organism, E. coli ATCC BAA-196. Several commonalities in responses of these phylogenetically distant microorganisms to the treatment with FS-1 were discovered, which included metabolic transition toward anaerobiosis and oxidative/osmotic stress response. S. aureus culture appeared to be more sensitive to FS-1 due to a higher penetrability of cells by iodine bound compounds, which caused carbonyl stress associated with nucleotide damaging by FS-1, abnormal epigenetic modifications and an increased rate of mutations. It was hypothesized that the disrupted pattern of adenine methylated loci within methicillin-resistance chromosome cassettes (SCCmec) may promote excision of this antibiotic resistance determinant from chromosomes while the altered pattern of cytosine methylation was behind the adaptive gene regulation in the culture FS. The selection against the antibiotic resistance in bacterial populations caused by abnormal epigenetic modifications exemplifies possible mechanisms of antibiotic resistance reversion induced by iodine-containing compounds. These finding will facilitate development of therapeutic agents against multidrug-resistant infections.

Synergy Effects of Metformin and Berberine on Glyoxal-induced Carbonyl Stress in Isolated Rat Liver Mitochondria

Objective: Carbonyl stress, resulting from toxic effects of alpha-dicarbonyls such as glyoxal (GO), plays an important role in mitochondrial dysfunction and subsequent development of diabetic complications. This study evaluated the ability of metformin (MET), berberine (BBR), and their combination to prevent GO-induced carbonyl stress in isolated rat liver mitochondria. Methods: Mitochondria (0.5 mg protein/mL) were isolated from the Wistar rat liver and incubated with various concentrations of GO (1, 2.5, 5, 7.5, and 10 mM) for 30 minutes and IC50 for GO was calculated. The suspensions of mitochondria were incubated with various concentrations of MET (2.5, 5, 10, and 20 mM) or BBR (2.5, 5, 10, and 20 μM) for 30 min and then GO in a dose of IC50 at 37 ºC for 30 min. Mitochondrial complex II activity, mitochondrial membrane potential (MMP), MDA level, reactive oxygen species (ROS) formation, reduced glutathione (GSH) content, and protein carbonylation were assessed. The combination index and isobologram of MET and BBR on GO toxicity were calculated. Results: IC50 of GO was assigned approximately 3 mM. GO disrupted the electron transfer chain and significantly increased mitochondrial ROS formation, protein carbonylation, and MDA level. GO decreased mitochondrial viability, MMP, and GSH content. Pre-treatment with MET and BBR could potentially reverse GO-induced deleterious effects in a concentration-dependent manner. Results of the drug combination indicated that CI for Fa 0.5 (Effect 50 %) was 0.83. Conclusion: These results suggest that BBR in combination with MET has a moderate synergistic effect on GO-induced carbonyl stress in isolated rat liver mitochondria.

Association between carbonyl stress markers and the risk of acute coronary syndrome in patients with type 2 diabetes mellitus–A pilot study

Background and aimsCarbonyl stress is one of the mechanisms responsible for diabetes and its complications. The study was planned to examine the relationship between carbonyl stress markers and the risk of acute coronary syndrome (ACS) in patients with type 2 diabetes mellitus (T2DM). MethodsForty T2DM patients with ACS and forty T2DM patients without ACS participated in this cross-sectional pilot study. Routine biochemical investigations, creatine kinase-total (CK-T), and creatine kinase-MB (CK-MB) levels were estimated. Serum carbonyl stress markers were analysed by enzyme-linked immunosorbent assay. Binary logistics regression was done to determine the predictive value of carbonyl stress markers for ACS. ResultsFasting plasma glucose, serum total methylglyoxal (MG), methylglyoxal derived hydroimidazolones-1 (MG-H1), and Nε-carboxymethyl-lysine (CML) levels were significantly higher in T2DM patients with ACS than in those without ACS. Serum glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glyoxalase-1 (GLO1) levels were significantly lower in T2DM patients with ACS than in those without ACS. Fasting plasma glucose level was significantly positively correlated with serum MG (r = 0.441, P < 0.001), CML (r = 0.649, P < 0.001), MG-H1 (r = 0.725, P < 0.001), and negatively correlated with serum GAPDH (r = – 0.268, P = 0.012) and GLO1 (r = – 0.634, P = 0.016). Receiver operating characteristic curve analysis showed that serum GAPDH and GLO1 could predict the risk of ACS in T2DM patients. ConclusionThese findings revealed that high carbonyl stress due to lower levels of GAPDH and GLO1 may predispose patients with T2DM for more risk of ACS.

Free radical reactions in socially significant infectious diseases: HIV infection, hepatitis, tuberculosis

The analysis of current literature data on the study of the features of the course of free-radical reactions, as well as the state of the antioxidant defense system at socially significant infectious diseases HIV infection, hepatitis, tuberculosis was carried out. The role of this kind of reaction in the genesis and progression of socially significant infections a long time has been studied. Foreign studies of recent years have been focused on the identification of specific markers of oxidative and carbonyl stress, which make it possible to identify the redox imbalance of the cell under conditions of infection and target affect it to modulate the activity of the main transcription factors of viral proteins and the bacteria pathogenicity. Numerous sources indicate the involvement of active oxygen metabolites in a wide range of events in infected cells and tissues, including neoplastic transformation processes. These biochemical markers can be used as additional criteria for monitoring the progression of infection. At the same time, noticeable gaps in this area there are that may become the goal of future research. The issues of changing free radical reactions depending on gender, age, place of residence of patients remain practically unstudied. There is little data about intensity of oxidative stress in patients of reproductive age with HIV, hepatitis B and C, and pulmonary tuberculosis, as well as the relationship of antioxidant deficiency with reproductive disorders in conditions of infection. These data could serve as the basis for the development of pathogenetically substantiated methods for the correction of socially significant infectious diseases. Modulation of the production of reactive oxygen metabolites and oxidative stress is a potentially new pharmacological approach to reduce the effects of viral and bacterial exposure.

Bioradical homeostasis as new complex parameters of different biological systems

The current state of free radical biomedicine allows us to formulate a fundamentally new parameter of homeostasis – homeostasis, understood as a state of free radical processes, reflecting the optimal intensity of the body metabolism of oxygen, nitrogen and halogens reactive species, carbonyls and other radical molecules. This term allows us to formulate another term – bioradical stress. It is proposed to understand the effective violation of the physiological level of free-radical processes associated with the formation of active forms of oxygen, nitrogen or halogens and/or a decrease in the activity of systems that limit their damaging effect. It combines all known syndromes associated with level shifts (oxidative, nitrosative, halogenating and carbonyl stress). The introduction of the concept of stress involves the study of the effectiveness of various options for specific pathogenetic correction of stress (the administration of antioxidants, directed stimulation of antioxidant capacity by active oxygen forms, the use of regulatory properties of NO, etc.). 800x600 Normal 0 false false false RU X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Обычная таблица; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif;}

DJ-1 Proteoforms in Breast Cancer Cells: The Escape of Metabolic Epigenetic Misregulation.

Enhanced glycolysis is a hallmark of breast cancer. In cancer cells, the high glycolytic flux induces carbonyl stress, a damaging condition in which the increase of reactive carbonyl species makes DNA, proteins, and lipids more susceptible to glycation. Together with glucose, methylglyoxal (MGO), a byproduct of glycolysis, is considered the main glycating agent. MGO is highly diffusible, enters the nucleus, and can react with easily accessible lysine- and arginine-rich tails of histones. Glycation adducts on histones undergo oxidization and further rearrange to form stable species known as advanced glycation end-products (AGEs). This modification alters nucleosomes stability and chromatin architecture deconstructing the histone code. Formation of AGEs has been associated with cancer, diabetes, and several age-related diseases. Recently, DJ-1, a cancer-associated protein that protects cells from oxidative stress, has been described as a deglycase enzyme. Although its role in cell survival results still controversial, in several human tumors, its expression, localization, oxidation, and phosphorylation were found altered. This work aimed to explore the molecular mechanism that triggers the peculiar cellular compartmentalization and the specific post-translational modifications (PTM) that, occurring in breast cancer cells, influences the DJ-1 dual role. Using a proteomic approach, we identified on DJ-1 a novel threonine phosphorylation (T125) that was found, by the in-silico tool scansite 4, as part of a putative Akt consensus. Notably, this threonine is in addition to histidine 126, a key residue involved in the formation of catalytic triade (glu18-Cys106-His126) inside the glioxalase active site of DJ. Interestingly, we found that pharmacological modulation of Akt pathway induces a functional tuning of DJ-1 proteoforms, as well as their shuttle from cytosol to nucleus, pointing out that pathway as critical in the development of DJ-1 pro-tumorigenic abilities. Deglycase activity of DJ-1 on histones proteins, investigated by coupling 2D tau gel with LC-MS/MS and 2D-TAU (Triton-Acid-Urea)-Western blot, was found correlated with its phosphorylation status that, in turn, depends from Akt activation. In normal conditions, DJ-1 acts as a redox-sensitive chaperone and as an oxidative stress sensor. In cancer cells, glycolytic rewiring, inducing increased reactive oxygen species (ROS) levels, enhances AGEs products. Alongside, the moderate increase of ROS enhances Akt signaling that induces DJ-1-phosphorylation. When phosphorylated DJ-1 increases its glyoxalase activity, the level of AGEs on histones decreases. Therefore, phospho-DJ-1 prevents glycation-induced histones misregulation and its Akt-related hyperactivity represents a way to preserve the epigenome landscape sustaining proliferation of cancer cells. Together, these results shed light on an interesting mechanism that cancer cells might execute to escape the metabolic induced epigenetic misregulation that otherwise could impair their malignant proliferative potential.

Enhanced carbonyl stress and disrupted white matter integrity in schizophrenia

Carbonyl stress is a state caused by an increase in rich reactive carbonyl compounds (RCOs); RCOs facilitate the formation of advanced glycation end products (AGEs), which are associated with various age-related illnesses. Recently, enhanced carbonyl stress and lower levels of pyridoxal, a kind of vitamin B6 that scavenges RCOs, have been shown to be associated with schizophrenia. Meanwhile, lower levels of pyridoxal have been reported to decrease myelination through the biochemical process of carbonyl stress. Despite a number of reports on white matter disruption in schizophrenia, it is unclear whether this disruption is related to enhanced carbonyl stress. Therefore, we investigated the relationship between carbonyl stress and white matter integrity in schizophrenia using diffusion tensor imaging. A total of 53 patients with schizophrenia and 83 age- and gender-matched healthy controls were recruited. We used plasma pentosidine, an AGE, and serum pyridoxal as carbonyl stress markers. Between-group differences in these carbonyl stress markers and their relationships with white matter integrity were investigated using Tract-Based Spatial Statistics. In the schizophrenia group, plasma pentosidine level was significantly higher and serum pyridoxal level was lower than those of controls. There was a significant negative correlation between plasma pentosidine and white matter integrity in the schizophrenia group, but not in the control group. Our findings suggest that enhanced carbonyl stress is a possible underlying mechanism of white matter microstructural disruption in schizophrenia.

Dynamics of indicators of cytolysis, carbonyl stress in patients with type 2 diabetes and non-alcoholic fatty liver disease on glucose-lowering therapies

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Effect of hypoglycemic therapy with forsiga on indicators of carbonyl (methylglyocal) and oxidative stress (MDA) in patients with NAFLD and type 2 diabetes

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Diabetes promotes invasive pancreatic cancer by increasing systemic and tumour carbonyl stress in KrasG12D/+ mice

BackgroundType 1 and 2 diabetes confer an increased risk of pancreatic cancer (PaC) of similar magnitude, suggesting a common mechanism. The recent finding that PaC incidence increases linearly with increasing fasting glucose levels supports a central role for hyperglycaemia, which is known to cause carbonyl stress and advanced glycation end-product (AGE) accumulation through increased glycolytic activity and non-enzymatic reactions. This study investigated the impact of hyperglycaemia on invasive tumour development and the underlying mechanisms involved.MethodsPdx1-Cre;LSL-KrasG12D/+ mice were interbred with mitosis luciferase reporter mice, rendered diabetic with streptozotocin and treated or not with carnosinol (FL-926-16), a selective scavenger of reactive carbonyl species (RCS) and, as such, an inhibitor of AGE formation. Mice were monitored for tumour development by in vivo bioluminescence imaging. At the end of the study, pancreatic tissue was collected for histology/immunohistochemistry and molecular analyses. Mechanistic studies were performed in pancreatic ductal adenocarcinoma cell lines challenged with high glucose, glycolysis- and glycoxidation-derived RCS, their protein adducts AGEs and sera from diabetic patients.ResultsCumulative incidence of invasive PaC at 22 weeks of age was 75% in untreated diabetic vs 25% in FL-926-16-gtreated diabetic and 8.3% in non-diabetic mice. FL-926-16 treatment suppressed systemic and pancreatic carbonyl stress, extracellular signal-regulated kinases (ERK) 1/2 activation, and nuclear translocation of Yes-associated protein (YAP) in pancreas. In vitro, RCS scavenging and AGE elimination completely inhibited cell proliferation stimulated by high glucose, and YAP proved essential in mediating the effects of both glucose-derived RCS and their protein adducts AGEs. However, RCS and AGEs induced YAP activity through distinct pathways, causing reduction of Large Tumour Suppressor Kinase 1 and activation of the Epidermal Growth Factor Receptor/ERK signalling pathway, respectively.ConclusionsAn RCS scavenger and AGE inhibitor prevented the accelerating effect of diabetes on PainINs progression to invasive PaC, showing that hyperglycaemia promotes PaC mainly through increased carbonyl stress. In vitro experiments demonstrated that both circulating RCS/AGEs and tumour cell-derived carbonyl stress generated by excess glucose metabolism induce proliferation by YAP activation, hence providing a molecular mechanism underlying the link between diabetes and PaC (and cancer in general).

Adeno-Associated Viral Transfer of Glyoxalase-1 Blunts Carbonyl and Oxidative Stresses in Hearts of Type 1 Diabetic Rats.

Accumulation of methylglyoxal (MG) arising from downregulation of its primary degrading enzyme glyoxalase-1 (Glo1) is an underlying cause of diabetic cardiomyopathy (DC). This study investigated if expressing Glo1 in rat hearts shortly after the onset of Type 1 diabetes mellitus (T1DM) would blunt the development of DC employing the streptozotocin-induced T1DM rat model, an adeno-associated virus containing Glo1 driven by the endothelin-1 promoter (AAV2/9-Endo-Glo1), echocardiography, video edge, confocal imaging, and biochemical/histopathological assays. After eight weeks of T1DM, rats developed DC characterized by a decreased E:A ratio, fractional shortening, and ejection fraction, and increased isovolumetric relaxation time, E: e’ ratio, and circumferential and longitudinal strains. Evoked Ca2+ transients and contractile kinetics were also impaired in ventricular myocytes. Hearts from eight weeks T1DM rats had lower Glo1 and GSH levels, elevated carbonyl/oxidative stress, microvascular leakage, inflammation, and fibrosis. A single injection of AAV2/9 Endo-Glo1 (1.7 × 1012 viron particles/kg) one week after onset of T1DM, potentiated GSH, and blunted MG accumulation, carbonyl/oxidative stress, microvascular leakage, inflammation, fibrosis, and impairments in cardiac and myocyte functions that develop after eight weeks of T1DM. These new data indicate that preventing Glo1 downregulation by administering AAV2/9-Endo-Glo1 to rats one week after the onset of T1DM, blunted the DC that develops after eight weeks of diabetes by attenuating carbonyl/oxidative stresses, microvascular leakage, inflammation, and fibrosis.

Preclinical pharmacology of a lipophenol in a mouse model of light-induced retinopathy

Environmental light has deleterious effects on the outer retina in human retinopathies, such as ABCA4-related Stargardt’s disease and dry age-related macular degeneration. These effects involve carbonyl and oxidative stress, which contribute to retinal cell death and vision loss. Here, we used an albino Abca4−/− mouse model, the outer retina of which shows susceptibility to acute photodamage, to test the protective efficacy of a new polyunsaturated fatty acid lipophenol derivative. Anatomical and functional analyses demonstrated that a single intravenous injection of isopropyl-phloroglucinol-DHA, termed IP-DHA, dose-dependently decreased light-induced photoreceptor degeneration and preserved visual sensitivity. This protective effect persisted for 3 months. IP-DHA did not affect the kinetics of the visual cycle in vivo or the activity of the RPE65 isomerase in vitro. Moreover, IP-DHA administered by oral gavage showed significant protection of photoreceptors against acute light damage. In conclusion, short-term tests in Abca4-deficient mice, following single-dose administration and light exposure, identify IP-DHA as a therapeutic agent for the prevention of retinal degeneration.

609 The topical tanning agent dihydroxyacetone induces stress response gene expression and signaling in human reconstructed epidermis and SKH1 hairless mouse skin

Chemical tanning is widely regarded as a safe alternative to solar UV-induced skin tanning, but the cutaneous biology impacted by chemical tanning remains largely unexplored. Chemical tanning is based on the formation of melanin-mimetic cutaneous pigments (‘melanoidins’) from spontaneous glycation reactions between epidermal amino acid/protein components and reactive sugars including the glycolytic ketose dihydroxyacetone (DHA). Here, we have examined cutaneous effects of acute DHA exposure on cultured human keratinocytes, epidermal reconstructs, and mouse skin employing gene epression array analysis and immunodetection. In human HaCaT keratinocytes, DHA (1-20 mM; 6 h) did not impair viability while causing a stress response with activation of phospho-protein signal transduction [p-p38, p-Hsp27, p-eIF2α] and gene expression (HSPA6, HMOX1, CRYAB, CCL3), not observed in response to the tanning-inactive DHA-control glycerol. Formation of DHA-specific advanced glycation endproducts resulting from posttranslational protein adduction was confirmed by mass spectrometric detection of N-ε-(carboxyethyl)-L-lysine and N7-carboxyethyl-L-arginine. Skin cells with CRISPR-Cas9 elimination of the carbonyl stress response gene GLO1 (glyoxalase 1) displayed hypersensitivity to DHA cytotoxicity. A topical DHA regimen elicited a similar stress response in human epidermal reconstructs [EpidermTM; 1-10% DHA in carrier; 6-24 h] as revealed by expression array (HSPA1A, HSPA6, HSPD1, IL6, DDIT3, EGR1) and IHC analysis (CEL, HO-1, p-Hsp27). In SKH1 mouse skin, gene expression analysis confirmed a topical DHA-induced stress response substantiated by IHC-detection of CEL and p-Hsp27. Given the worldwide use of chemical tanners including DHA in consumer products these prototype data deserve further molecular exploration in living human skin.

The Microbial Biotransformation of Soy Genistein Significantly Enhances Its Trapping Capacities of Reactive Carbonyl Metabolites

Abstract Objectives Carbonyl stress is the abnormal accumulation of carbonyl metabolites, such as methylglyoxal (MGO) and acrolein (ACR) that leads to increased modification of protein, lipids and DNA, and contributes to cell and tissue dysfunction resulting in aging and diseases, such as diabetes, cardiovascular diseases and neurodegenerative diseases. Carbonyl stress is caused by an imbalance in the formation and metabolism of carbonyl metabolites and also by increased exposure to exogenous carbonyl species. In vitro studies have shown that dietary flavonoids have the capacities to detoxify reactive carbonyl metabolites. However, whether flavonoids can trap carbonyl metabolites in vivo and whether biotransformation especially microbial metabolism limits the trapping capacities of flavonoids remain virtually unknown. The objective of this study is to use soy genistein as an example to test the impacts of bioavailability and biotransformation on the in vivo trapping capacities of RCS by genistein. Methods Chemically, we synthesized the MGO and ACR conjugates of genistein as authentic standards. In mice, we oral gavaged 200 mg/kg genistein or vehicle to mice. Urine and feces were collected in metabolic cages for 24 h. The urine samples from genistein treated mice were also used to prepare the RCS conjugates of genistein metabolites. Using LC tandem mass and the high-resolution accurate mass, we searched and identified the formation of genistein metabolites and their corresponding RCS conjugates. The RCS conjugates of genistein and its metabolites were also quantified using the synthetic standards. Results We found that 1) absorbed genistein trapped endogenous MGO and ACR by forming mono-RCS adducts and eventually be excreted into mouse urine; 2) absorbed genistein could produce active phase I metabolite, orobol, to scavenge endogenous MGO and ACR; and 3) considerable amounts of microbial metabolites of genistein displayed enhanced anti-RCS capacity both in the body and in the gut, compared to genistein. Conclusions Our findings demonstrate that in vivo anti-RCS ability of dietary polyphenols cannot be reflected solely based on their in vitro ability. The bioavailability and biotransformation of individual polyphenols especially gut microbiome contribute to in vivo anti-RCS ability of dietary polyphenols. Funding Sources N/A.

The sunless tanning agent dihydroxyacetone induces stress response gene expression and signaling in cultured human keratinocytes and reconstructed epidermis

Sunless (chemical) tanning is widely regarded as a safe alternative to solar UV-induced skin tanning known to be associated with epidermal genotoxic stress, but the cutaneous biology impacted by chemical tanning remains largely unexplored. Chemical tanning is based on the formation of melanin-mimetic cutaneous pigments (‘melanoidins’) from spontaneous amino-carbonyl (‘glycation’) reactions between epidermal amino acid/protein components and reactive sugars including the glycolytic ketose dihydroxyacetone (DHA). Here, we have examined the cutaneous effects of acute DHA-exposure on cultured human HaCaT keratinocytes and epidermal reconstructs, profiled by gene expression array analysis and immunodetection. In keratinocytes, DHA-exposure performed at low millimolar concentrations did not impair viability while causing a pronounced cellular stress response as obvious from rapid activation of phospho-protein signal transduction [p-p38, p-Hsp27(S15/S78), p-eIF2α] and gene expression changes (HSPA6, HMOX1, CRYAB, CCL3), not observable upon exposure to the non-ketose, tanning-inactive DHA-control glycerol. Formation of advanced glycation end products (AGEs) from posttranslational protein-adduction was confirmed by quantitative mass spectrometric detection of N-ε-(carboxyethyl)-l-lysine (CEL) and N7-carboxyethyl-l-arginine, and skin cells with CRISPR-Cas9-based elimination of the carbonyl stress response gene GLO1 (encoding glyoxalase 1) displayed hypersensitivity to DHA-cytotoxicity. In human epidermal reconstructs a topical use-relevant DHA-dose regimen elicited a comparable stress response as revealed by gene expression array (HSPA1A, HSPA6, HSPD1, IL6, DDIT3, EGR1) and immunohistochemical analysis (CEL, HO-1, p-Hsp27-S78). In DHA-treated SKH-1 hairless mouse skin IHC-detection revealed epidermal occurrence of CEL- and p-Hsp27-epitopes. For comparison, stress response gene expression array analysis was performed in epidermis exposed to a supra-erythemal dose of solar simulated UV (2 MEDs), identifying genes equally or differentially sensitive to either one of these cutaneous stimuli [DHA (‘sunless tanning’) versus solar UV (‘sun-induced tanning’)]. Given the worldwide use of chemical tanners in consumer products, these prototype data documenting a DHA-induced specific cutaneous stress response deserve further molecular exploration in living human skin.

Carbonyl Cytotoxicity Affects Plant Cellular Processes and Detoxifying Enzymes Scavenge These Compounds to Improve Stress Tolerance

Oxidative stress is ubiquitous in environmental stresses and prevails over the cellular metabolic and phenotypic responses in plants. Reactive oxygen species (ROS) generated under stress affect macromolecules to form another group of toxic compounds called reactive carbonyl compounds (RCCs). These molecules have a longer half-life than ROS and cause carbonyl stress that affects cellular metabolism, cellular homeostasis, and crop productivity. The later effect of oxidative stress in terms of the generation of RCCs and glycation products and their effects on plant processes have not been explored well in plant biology. Therefore, how these molecules are produced and a few important effects of RCCs on plants have been discussed in this review article. Further, the plant adaptive detoxification mechanisms of RCCs have been discussed. The enzymes that were identified in plants to detoxify these cytotoxic compounds have broad substrate specificity and the potential for use in breeding programs. The review should provide a comprehensive understanding of the cytotoxic compounds beyond ROS and subsequently their mitigation strategies for crop improvement programs.