Levels of circulating GRP78 and CHOP in endoplasmic reticulum stress pathways in Chinese type 2 diabetic kidney disease patients.

ABSTRACT: The current study aimed to investigate circulating glucose-regulated protein 78 (GRP78) as well as CCAAT/enhancer-binding protein homologous protein (CHOP) concentrations in Chinese type 2 diabetes mellitus (T2DM) patients, especially those with microalbuminuria. We recruited 67 patients with T2DM and 63 control subjects. We determined circulating GRP78 and CHOP concentrations by ELISA, collected anthropometric data, and measured biochemical parameters in a clinical laboratory. Compared with control groups, patients with T2DM showed decreased circulating levels of GRP78 (0.21 [0.16-0.24] vs 0.16 [0.16-0.19] ng/mL, P < .01) and CHOP ([0.29 ±â€Š0.02] vs [0.27 ±â€Š0.03]ng/mL, P < .01). Reduction in circulating GRP78 and CHOP levels was more pronounced in patients with more severe categories of albuminuria. Amounts of circulating GRP78 correlated directly with serum fasting c-peptide, cystatin-c (Cys-c), creatinine (Cr), blood urea nitrogen (BUN), and uric acid, and inversely with glomerular filtration rates. Circulating CHOP level was positively correlated with age, Cr, BUN, Cys-c, and urinary microalbumin/creatinine (UmALB/Cr). Circulating GRP78 was predicted independently by Cr, BUN, serum uric acid, estimated glomerular filtration rate, and Cys-c, while CHOP depended on age, Cr, BUN, estimated glomerular filtration rate, UmALB/Cr, and Cys-c. After controlling for confounding factors, circulating GRP78 and CHOP expression were significantly associated with diabetic kidney disease (binary logistic regression, P < .01). Patients with T2DM showed increased circulating GRP78 and CHOP concentrations. Receiver operating characteristic areas under the curve for predicting diabetic kidney disease based on GRP78 and CHOP were 0.686 (95% CI: 0.558-0.813) and 0.670 (0.524-0.816), respectively.

Endoplasmic Reticulum Stress Markers in SARS-COV-2 Infection and Pneumonia: Case-Control Study.

BACKGROUND/AIM: A novel human coronavirus, named SARS-COV-2, has recently caused thousands of deaths all around the world. Endoplasmic reticulum (ER) stress plays an important role in the development of diseases. PATIENTS AND METHODS: We aimed to to investigate the relationship between ER stress markers in patients infected with SARS-COV-2 and patients with pneumonia. A total of 9 patients (4 patients diagnosed with pneumonia and 5 patients diagnosed with SARS-COV-2 infection) who admitted to the emergency Department with symptoms of pneumonia and SARS-COV-2 were included in the study. A total of 18 healthy individuals without any known chronic or acute disease and drug use were included as the healthy control group. Serum human glucose regulated protein 78 (GRP78), serum human C/EBP homologous protein (CHOP) and serum human phospho extracellular signal regulated kinase (PERK) levels were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: GRP78 levels were found to be significantly higher in SARS-COV-2 positive cases compared to individuals in other groups. Serum GRP-78 level median value was statistically significantly higher in SARS-COV-2-positive group compared to the other groups (p=0.0003). Serum PERK level was statistically significantly higher in SARS-COV-2-positive pneumonia cases (p=0.046). CONCLUSION: An association was shown between GRP78 and SARS-COV-2 infection. Although a small number of patients was investigated, these results will be important and guide future treatments of SARS-COV-2.

Effect of vitamin B12 supplementation on retinal lesions in diabetic rats.

Purpose: Diabetic retinopathy (DR) is the most common complication of diabetes involving microvasculature and neuronal alterations in the retina. Previously, we reported that vitamin B12 deficiency could be an independent risk factor for DR in humans. However, the effect of vitamin B12 supplementation in experimental DR is unknown. Thus, in this study, we investigated the impact of dietary supplementation of vitamin B12 on retinal changes in diabetic rats. Methods: Diabetes was induced in 2-month-old Sprague-Dawley rats and maintained for 4 months. One group of diabetic rats were fed normal levels of vitamin B12, and one group double the quantity of vitamin B12 (50 µg/kg diet). Vitamin B12 and homocysteine levels in the plasma were analyzed with radioimmunoassay (RIA) and high-performance liquid chromatography (HPLC), respectively. At the end of 4 months of experimentation, the eyeballs were collected. Retinal changes were analyzed with hematoxylin and eosin (H&E) staining, immunoblotting, and immunofluorescence methods. Results: Dietary supplementation of vitamin B12 had no effect on food intake, bodyweight, fasting blood glucose, and plasma homocysteine levels in the diabetic rats. However, vitamin B12 supplementation prevented loss of rhodopsin, and overexpression of VEGF, and completely prevented overexpression of HIF1α, GFAP, and endoplasmic reticulum (ER) stress markers (GRP78, ATF6α, XBP1, CHOP, and caspase 12) in the diabetic rat retina. Further, vitamin B12 ameliorated apoptosis in the retina as shown with terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and prevented retinal thinning. Conclusions: Vitamin B12 supplementation of diabetic rats appeared to be beneficial by circumventing retinal hypoxia, VEGF overexpression, and ER stress-mediated cell death in the retina. The present study adds another potential therapeutic strategy of vitamin B12 in diabetes.

Potential biomarker identification for Friedreich's ataxia using overlapping gene expression patterns in patient cells and mouse dorsal root ganglion.

Friedreich's ataxia (FA) is a neurodegenerative disease with no approved therapy that is the result of frataxin deficiency. The identification of human FA blood biomarkers related to disease severity and neuro-pathomechanism could support clinical trials of drug efficacy. To try to identify human biomarkers of neuro-pathomechanistic relevance, we compared the overlapping gene expression changes of primary blood and skin cells of FA patients with changes in the Dorsal Root Ganglion (DRG) of the KIKO FA mouse model. As DRG is the primary site of neurodegeneration in FA, our goal was to identify which changes in blood and skin of FA patients provide a 'window' into the FA neuropathomechanism inside the nervous system. In addition, gene expression in frataxin-deficient neuroglial cells and FA mouse hearts were compared for a total of 5 data sets. The overlap of these changes strongly supports mitochondrial changes, apoptosis and alterations of selenium metabolism. Consistent biomarkers were observed, including three genes of mitochondrial stress (MTIF2, ENO2), apoptosis (DDIT3/CHOP), oxidative stress (PREX1), and selenometabolism (SEPW1). These results prompted our investigation of the GPX1 activity as a marker of selenium and oxidative stress, in which we observed a significant change in FA patients. We believe these lead biomarkers that could be assayed in FA patient blood as indicators of disease severity and progression, and also support the involvement of mitochondria, apoptosis and selenium in the neurodegenerative process.

Impact of general anaesthesia on endoplasmic reticulum stress: propofol vs. isoflurane.

Background: This study investigated the effects of propofol and isoflurane on endoplasmic reticulum (ER) stress in an animal model under general anaesthesia. Methods: Rats were randomly divided into Propofol and Isoflurane groups. Anaesthesia was maintained with propofol for Propofol group or isoflurane for Isoflurane group during 3 h. ER stress from lymphocytes in blood and tissues was evaluated between two groups after euthanasia. Reactive oxygen species (ROS) from lymphocytes in blood and tissues, and cytokines in blood were also checked. An immunohistochemical assay for ER stress marker from tissues was performed. Results: After anaesthesia, the levels of CCAAT-enhancer-binding protein homologous proteins (CHOP) in blood and liver were significantly higher in Isoflurane group, compared to Propofol group [blood, 31,499 ± 4,934 (30,733, 26,441-38,807) mean fluorescence intensity (MFI) in Isoflurane group vs. 20,595 ± 1,838 (20,780, 18,866-22,232) MFI in Propofol group, p = 0.002; liver, 28,342 ± 5,535 (29,421, 23,388-32,756) MFI in Isoflurane group vs. 20,004 ± 2,155 (19,244, 18,197-22,191) MFI in Propofol group, p = 0.020]. ROS in blood was significantly higher in Isoflurane group, compared to Propofol group. However, cytokines in blood and immunohistochemical assays in tissues were similar between groups. Conclusion: Significant higher of ER stress from blood and liver were observed in rats under anaesthesia with isoflurane, compared to those that received propofol. ROS from blood also showed significant higher under anaesthesia with isoflurane. However, these findings were not associated with any changes in cytokines in blood or immunohistochemical assay in tissues.

Expression of LRP1 and CHOP genes associated with peripheral neuropathy in type 2 diabetes mellitus: Correlations with nerve conduction studies.

AIM: Diabetic peripheral neuropathy (DPN) is a frequent and debilitating complication of diabetes mellitus. The low-density lipoprotein receptor-related protein-1 (LRP-1) is a multifunctional cell surface receptor playing critical roles in lipoprotein metabolism and several cell signaling processes. C/EBP homologous protein (CHOP) is a main conduit to endoplasmic reticulum stress-induced apoptosis. We aimed to investigate LRP1 and CHOP gene expression in peripheral blood cells of type 2 diabetes mellitus (T2DM) subjects to clarify its possible relation to DPN pathogenesis. METHOD: The study included 20 non-complicated T2DM subjects, 20 subjects with DPN and 20 healthy controls. Quantitative real time PCR was used to study gene expression. RESULTS: There was a significant reduction in LRP1 mRNA expression and a significant increase in CHOP mRNA expression in subjects with DPN compared to non-complicated group and healthy controls. Both LRP1 and CHOP expression levels were inversely correlated, and both showed significant correlation with HbA1c, hyperlipidemia, hs-CRP, and different electrophysiological parameters. Receiver operating characteristics (ROC) analysis suggested that both LRP1 and CHOP mRNA expression and hs-CRP levels had great potential advantages to predict the progression of DPN. CONCLUSION: LRP1 and CHOP might be involved in DPN pathogenesis and progression, thus providing opportunities for early detection and treatment.

C/EBP homologous protein investigation in the serum and cerebro-spinal fluid of relapsing-remitting multiple sclerosis patients.

The exact determination of endoplasmic reticulum (ER) stress-associated proteins is not completely elucidated in the multiple sclerosis (MS) patients. We measured CHOP concentrations in the serum and cerebro-spinal fluid (CSF) of relapsing-remitting MS (RRMS) patients (n = 20) in comparison with the non-MS control group (n = 20) to determine whether this marker could be detected in the body fluids of RRMS patients. CHOP marker was not detectable in all harvested CSF samples. However, its levels were detectable in all serums harvested from both non-MS and RRMS patients and its levels in the latter group were not significantly higher than those of the non-MS control group (P value = 0.265). CHOP was not detectable in the CSF of RRMS patients in spite of the recent reports on the RRMS autopsies. Additionally, there were not any significant correlations (Spearman's correlation) between both of EDSS score and age with CHOP serum concentrations in all subjects.

Endoplasmic reticulum stress in bipolar disorder? - BiP and CHOP gene expression- and XBP1 splicing analysis in peripheral blood.

BACKGROUND: Endoplasmic Reticulum stress activates the Unfolded Protein Response, which is partially impaired in Bipolar Disorder (BD) according to previous in-vitro studies. Thus, BiP and CHOP gene expression and XBP1 splicing were analyzed in peripheral blood of study participants with BD and controls. METHODS: RNA was isolated from fasting blood of study participants with BD (n = 81) and controls (n = 54) and reverse transcribed into cDNA. BiP and CHOP gene expression was analyzed with quantitative RT-PCR. Atypical splicing of XBP1 mRNA was measured by semi-quantitative RT-PCR, gel-electrophoresis and densitometry. ANCOVAs with the covariates age, BMI, sex, lithium and anticonvulsants intake were used with SPSS. Bonferroni correction was used to correct for multiple testing (adjusted p = 0.0083). RESULTS: BiP gene expression was significantly higher in BD than in controls (F(1/128) = 10.076, p = 0.002, Partial η2 = 0.073). Total XBP1 (F(1/126) = 9.550, p = 0.002, Partial η2 = 0.070) and unspliced XBP1 (F(1/128)= 8.803, p= 0.004, Patial η2 = 0.065) were significantly decreased in BD. Spliced XBP1 (F(1/126) = 5.848, p = 0.017, Partial η2 = 0.044) and the ratio spliced XBP1/ unspliced XBP1 did not differ between BD and controls (F(1/126) = 0.599, p = 0.441, Partial η2 = 0.005). Gene expression did not differ between euthymia, depression and mania. DISCUSSION: BiP gene expression was significantly higher in BD compared to controls. Total and unspliced XBP1 were significantly lower in BD than in the control group. Thus, both genes may be considered as putative trait markers. Nevertheless, XBP1 splicing itself did not differ between both groups.

Various cellular stress components change as the rat ages: An insight into the putative overall age-related cellular stress network.

Cellular stress is mainly comprised of oxidative, nitrosative, and endoplasmic reticulum stresses and has long been correlated to the ageing process. Surprisingly, the age-related difference among the various components in each independent stress pathway and the possible significance of these components in relation to the overall cellular stress network remain to be clearly elucidated. In this study, we obtained blood from ageing rats upon reaching 20-, 40-, and 72-wk.-old. Subsequently, we measured representative cellular stress-linked biomolecules (H2O2, glutathione reductase, heme, NADPH, NADP, nitric oxide, GADD153) and cell signals [substance P (SP), free fatty acid, calcium, NF-κB] in either or both blood serum and cytosol. Subsequently, network analysis of the overall cellular stress network was performed. Our results show that there are changes affecting stress-linked biomolecules and cell signals as the rat ages. Additionally, based on our network analysis data, we postulate that NADPH, H2O2, GADD153, and SP are the key components and the interactions between these components are central to the overall age-related cellular stress network in the rat blood. Thus, we propose that the main pathway affecting the overall age-related cellular stress network in the rat blood would entail NADPH-related oxidative stress (involving H2O2) triggering GADD153 activation leading to SP induction which in-turn affects other cell signals.

Stress kinases, endoplasmic reticulum stress, and Alzheimer's disease related markers in peripheral blood mononuclear cells from subjects with increased body weight.

We aimed to characterize endoplasmic reticulum stress, inflammation, and Alzheimer's disease (AD) related markers in peripheral blood mononuclear cells (PBMCs) from males with varied BMI; and to explore whether high glucose and fatty acids (FFAs) might be critical factors for inducing metabolic alterations in PBMCs under obese condition. Approximately 45 middle-aged men were enrolled with varied BMI. At the protein expression level, compared to the lean, the phosphorylation of AMPK, and p-Akt at serine 473 were significantly reduced from the overweight (OW) and/or obese (OB); while the protein expression of p-JNK, cleaved caspase 3, CHOP and p-eIF2α were elevated from the OW and/or OB. At the mRNA expression level, ER stress markers (i.e. GRP78, CHOP and XBP-1), inflammatory markers (i.e.TLR2, TLR4 and CCR2) and AD markers (i.e. APP, PS1 and PS2) were significantly higher in PBMCs from OB compared to lean. In cultured PBMCs, high glucose and FFAs induced GRP78, CHOP and XBP-1 mRNA, and high glucose also induced APP, PS1 and PS2 mRNA. In conclusion, altered markers including AMPK, ER stress and AD related makers under obese condition could be easily obtained from PBMCs. These markers might provide new mechanistic links between obesity and other metabolic complications including AD.

Periodontal disease level-butyric acid amounts locally administered in the rat gingival mucosa induce ER stress in the systemic blood.

Periodontal diseases have long been postulated to contribute to systemic diseases and, likewise, it has been proposed that periodontal disease treatment may ameliorate certain systemic diseases. Short-chain fatty acids (SCFA) are major secondary metabolites produced by oral anaerobic bacteria and, among the SCFAs, butyric acid (BA) in high amounts contribute to periodontal disease development. Periodontal disease level-butyric acid (PDL-BA) is found among patients suffering from periodontal disease and has previously shown to induce oxidative stress, whereas, oxidative stress is correlated to endoplasmic reticulum (ER) stress. This would imply that PDL-BA may likewise stimulate ER stress, however, this was never elucidated. A better understanding of the correlation between PDL-BA and systemic ER stress stimulation could shed light on the possible systemic effects of PDL-BA-related periodontal diseases. Here, PDL-BA was injected into the gingival mucosa and the systemic blood obtained from the rat jugular was collected at 0, 15, 60, and 180 min post-injection. Collected blood samples were purified and only the blood cytosol was used throughout this study. Subsequently, we measured blood cytosolic GADD153, Ca(2+), representative apoptotic and inflammatory caspases, and NF-κB amounts. We found that PDL-BA presence increased blood cytosolic GADD153 and Ca(2+) amounts. Moreover, we observed that blood cytosolic caspases and NF-κB were activated only at 60 and 180 min post-injection in the rat gingival mucosa. This suggests that PDL-BA administered through the gingival mucosa may influence the systemic blood via ER stress stimulation and, moreover, prolonged PDL-BA retention in the gingival mucosa may play a significant role in ER stress-related caspase and NF-κB activation. In a periodontal disease scenario, we propose that PDL-BA-related ER stress stimulation leading to the simultaneous activation of apoptosis and inflammation may contribute to periodontal disease pathogenesis.