OBJECTIVE: To explore the interaction between reactive oxygen species (ROS) and ferroptosis in methylglyoxalinduced injury of mouse embryonic osteoblasts (MC3T3-E1 cells). METHODS: MC3T3-E1 cells were treated with methylglyoxal to establish a cell model of diabetic osteoporosis. CCK-8 assay was used to detect the viability of MC3T3-E1 cells. Rhodamine 123 staining followed by photofluorography was used to examine mitochondrial membrane potential (MMP). The intracellular ROS level was detected by 2', 7'-dichlorodihydrofluorescein diacetate staining with photofluorograph. Alkaline phosphatase (ALP) activity in the cells was detected using an ALP kit, the number of mineralized nodules was determined with alizarin red S staining, and the level of iron ions was detected using a detection kit. The expression level of glutathione peroxidase 4 (GPX4, a marker protein that inhibits ferroptosis) in the osteoblasts was determined using Western blotting. RESULTS: Treatment of MC3T3-E1 cells with 0.6 mmol/L methylglyoxal for 24 h significantly inhibited the expression level of GPX4 (P < 0.001), increased intracellular iron ion concentration, decreased the cell viability, increased the loss of MMP and intracellular ROS level, decreased both ALP activity and the number of mineralized nodules in the cells (P < 0.001). Co-treatment of MC3T3-E1 cells with 2 mmol/L N-acetylcysteine (NAC, a ROS scavenger) and methylglyoxal significantly increased the expression level of GPX4 (P < 0.01); co-treatment with 4 mmo/L FER-1 (a ferroptosis inhibitor) and methylglyoxal obviously decreased the intracellular ROS level (P < 0.001). Co-treatment of the cells either with NAC and methylglyoxal or with FER-1 and methylglyoxal attenuated methylglyoxal-induced injuries in the osteoblasts (P < 0.001). CONCLUSION The interaction between ROS and ferroptosis pathway plays an important role in methylglyoxal-induced injury of mouse embryonic osteoblasts.
Animals ; Cell Survival ; Ferroptosis ; Mice ; Osteoblasts ; Pyruvaldehyde/metabolism* ; Reactive Oxygen Species/metabolism*

Oxidative stress and methylglyoxal (MG), a reactive dicarbonyl metabolites produced by enzymatic and non-enzymatic reaction of normal metabolism, induced aldose reductase (AR) expression in rat aortic smooth muscle cells (SMC). AR expression was induced in a time-dependent manner and reached at a maximum of 4.5-fold in 12 h of MG treatment. This effect of MG was completely abolished by cyclohemide and actinomycin D treatment suggesting AR was synthesized by de novo pathway. Pretreatment of the SMC with N-acetyl-L-cysteine significantly down-regulated the MG-induced AR mRNA. Furthermore, DL-Buthionine-(S,R)-sulfoximine, a reagent which depletes intracellular glutathione levels, increased the levels of MG-induced AR mRNA. These results indicated that MG induces AR mRNA by increasing the intracellular peroxide levels. Aminoguanidine, a scanvenger of dicarbonyl, significantly down-regulated the MG-induced AR mRNA. In addition, the inhibition of AR activities with statil, an AR inhibitor, enhanced the cytotoxic effect of MG on SMC under normal glucose, suggesting a protective role of AR against MG-induced cell damages. These results imply that the induction of AR by MG may contribute to an important cellular detoxification of reactive aldehyde compounds generated under oxidative stress in extrahepatic tissues.
Acetylcysteine ; Aldehyde Reductase* ; Animals ; Dactinomycin ; Glucose ; Glutathione ; Metabolism ; Muscle, Smooth, Vascular* ; Myocytes, Smooth Muscle ; Oxidative Stress* ; Pyruvaldehyde ; Rats ; RNA, Messenger

OBJECTIVETo explore the effects of methylglyoxal on endothelia cell migration.

METHODSHuman umbilical vein endothelial cells (HUVECs) were stimulated by serial concentrations of methylglyoxal (MGO, 0, 25, 50, 100 and 200 µmol/L) for 24 h, and the cell migration was assessed by scratch wound and Transwell assay. The expression of integrin β3 in the treated cells was examined by immunoblotting, and the effect of an anti-β3 antibody, LM609, on cell migration was investigated.

RESULTSMethylglyoxal significantly inhibited HUVEC migration in a concentration-dependent manner (P<0.05). Methylglyoxal decreased the expression of integrin β3 in a time- and concentration-dependent manner (P<0.05). LM609 also significantly inhibited HUVEC migration (P<0.05).

CONCLUSIONMethylglyoxal inhibits HUVEC migration in vitro by down-regulating integrin β3 expression.

Cell Movement ; drug effects ; Cells, Cultured ; Down-Regulation ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Integrin beta3 ; metabolism ; Pyruvaldehyde ; pharmacology

OBJECTIVETo evaluate the effects of aminoguanidine on methylglyoxal-mediated oxygen-glucose deprivation (OGD) injury in the cultured human brain microvascular endothelial cells (HBMEC).

METHODSCultured HBMEC cells were pretreated with methylglyoxal before oxygen-glucose deprivation injury. Cell vitality was determined by MTT method, cell mortality was assessed by LDH release method, cell apoptosis was examined by Annexin V/PI formation method, and the advanced glycation end products (AGEs) were detected by Western-blot.

RESULTSMethylglyoxal induced HBMEC injury in a dose-dependent manner. At 2 mmol/L of methylglyoxal, the cell viability was 56.1% when methylglyoxal-pretreated cells exposed to oxygen-glucose deprivation, the cell inhibition rate was 90.0%. Aminoguanidine (1 mmol/L) inhibited methylglyoxal and OGD induced LDH release and Annexin V/PI formation. Furthermore, aminoguanidine (1 mmol/L) also decreased advanced glycation end products (AGEs) formation induced by methylglyoxal and oxygen-glucose deprivation.

CONCLUSIONAminoguanidine protected methylglyoxal mediated-oxygen-glucose deprivation injury in the cultured HBMEC, which may be associated with anti-glycation activity.

Apoptosis ; drug effects ; Cell Hypoxia ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Drug Antagonism ; Endothelial Cells ; drug effects ; metabolism ; pathology ; Endothelium, Vascular ; cytology ; Glycation End Products, Advanced ; metabolism ; Guanidines ; pharmacology ; Humans ; Pyruvaldehyde ; pharmacology

One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive -dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 micrometer) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kB activation and increased caspase- 3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF- kB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kB are involved in the apoptotic process.
Acetylcysteine/pharmacology ; Animals ; *Apoptosis ; Caspases/metabolism ; Cattle ; Cell Death ; Cell Survival ; DNA Fragmentation ; Dose-Response Relationship, Drug ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Glucose/metabolism ; NF-kappa B/metabolism ; Nucleosomes/metabolism ; Oxidative Stress ; Pericytes/*drug effects ; Pyruvaldehyde/*pharmacology ; *Reactive Oxygen Species ; Retina/cytology/*drug effects

Fibrinogen is a key protein involved in coagulation and its deposition on blood vessel walls plays an important role in the pathology of atherosclerosis. Although the causes of fibrinogen (fibrin) deposition have been studied in depth, little is known about the relationship between fibrinogen deposition and reactive carbonyl compounds (RCCs), compounds which are produced and released into the blood and react with plasma protein especially under conditions of oxidative stress and inflammation. Here, we investigated the effect of glycolaldehyde on the activity and deposition of fibrinogen compared with the common RCCs acrolein, methylglyoxal, glyoxal and malondialdehyde. At the same concentration (1 mmol/L), glycolaldehyde and acrolein had a stronger suppressive effect on fibrinogen activation than the other three RCCs. Fibrinogen aggregated when it was respectively incubated with glycolaldehyde and the other RCCs, as demonstrated by SDS-PAGE, electron microscopy and intrinsic fluorescence intensity measurements. Staining with Congo Red showed that glycolaldehyde- and acrolein-fibrinogen distinctly formed amyloid-like aggregations. Furthermore, the five RCCs, particularly glycolaldehyde and acrolein, delayed human plasma coagulation. Only glycolaldehyde showed a markedly suppressive effect on fibrinogenesis, none did the other four RCCs when their physiological blood concentrations were employyed, respectively. Taken together, it is glycolaldehyde that suppresses fibrinogenesis and induces protein aggregation most effectively, suggesting a putative pathological process for fibrinogen (fibrin) deposition in the blood.
Acetaldehyde ; analogs & derivatives ; blood ; chemistry ; Acrolein ; blood ; chemistry ; Blood Coagulation ; Congo Red ; Electrophoresis, Polyacrylamide Gel ; Fibrinogen ; chemistry ; metabolism ; Glyoxal ; blood ; chemistry ; Humans ; Malondialdehyde ; chemistry ; Polymerization ; Protein Carbonylation ; Pyruvaldehyde ; blood ; chemistry ; Solutions ; Spectrometry, Fluorescence ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Thrombin ; chemistry