Dilated Endoplasmic Reticulum Research Articles

SARS-CoV-2 infection of the liver directly contributes to hepatic impairment in patients with COVID-19

Background & AimsLiver enzyme abnormalities are common in patients with coronavirus disease 2019 (COVID-19). Whether or not severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to liver damage per se remains unknown. Herein, we reported the clinical characteristics and liver pathological manifestations of COVID-19 patients with liver enzyme abnormalities.MethodsWe analyzed 156 patients diagnosed with COVID-19 from 2 designated centers in China and compared clinical features between patients with or without elevated aminotransferases. Postmortem liver biopsies were obtained from 2 cases who had elevated aminotransferases. We investigated the patterns of liver impairment by electron microscopy, immunohistochemistry, TUNEL assay and pathological studies.ResultsSixty-four out of 156 (41.0%) patients with COVID-19 had elevated aminotransferases. The median levels of alanine aminotransferase were 50 U/L vs. 19 U/L, respectively, aspartate aminotransferase were 45.5 U/L vs. 24 U/L, respectively in abnormal and normal aminotransferase groups. Liver enzyme abnormalities were associated with disease severity, as well as a series of laboratory tests including higher alveolar-arterial oxygen partial pressure difference, higher gamma-glutamyltransferase, lower albumin, decreased CD4+ T cells and B lymphocytes. Ultrastructural examination identified typical coronavirus particles, characterized by spike structures, in the cytoplasm of hepatocytes in 2 COVID-19 cases. SARS-CoV-2-infected hepatocytes displayed conspicuous mitochondrial swelling, endoplasmic reticulum dilatation and glycogen granule decrease. Histologically, massive hepatic apoptosis and some binuclear hepatocytes were observed. Taken together, both ultrastructural and histological evidence indicated a typical lesion of viral infection. Immunohistochemical results showed scarce CD4+ and CD8+ lymphocytes. No obvious eosinophil infiltration, cholestasis, fibrin deposition, granuloma, massive central necrosis, or interface hepatitis were observed.ConclusionsSARS-CoV-2 infection in the liver directly contributes to hepatic impairment in patients with COVID-19. Hence, a surveillance of viral clearance in liver and long-term outcome of COVID-19 is required.Lay summaryLiver enzyme abnormalities are common in patients with coronavirus disease 2019 (COVID-19). We reported the clinical characteristics and liver pathological manifestations of COVID-19 patients with elevated liver enzymes. Our findings suggested that SARS-CoV-2 infection of the liver is a crucial factor contributing to hepatic impairment in patients with COVID-19.

Dendrobium nobile Lindl alkaloid and metformin ameliorate cognitive dysfunction in senescence-accelerated mice via suppression of endoplasmic reticulum stress

The senescence-accelerated mouse prone 8 (SAMP8) mice have many pathological features of Alzheimer’s disease (AD) with aging. We previously reported that Dendrobium nobile Lindl alkaloid (DNLA) effectively improved cognitive deficits in multiple Alzheimer’s disease (AD) models. This study further used SAMP8 mice to study the anti-aging effects of DNLA, focusing on endoplasmic reticulum (ER) stress. DNLA and metformin were orally administered to SAMP8 mice starting at 4-month of age for 6 months. Behavioral tests were performed in 10-month-old SAMP8 mice and age-matched SAMR1 control mice. At the end of experiment, neuron damage was evaluated by histology and transmission electron microscopy. ER stress-related proteins were analyzed with Western-blot. DNLA improved learning and memory impairments, reduced the loss of neurons and Nissl bodies in the hippocampus and cortex. DNLA ameliorated ER dilation and swelling in the hippocampal neurons. DNLA down-regulated the protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway, decreased calpain 1, GSK-3β and Cdk5 activities and the Tau hyper-phosphorylation. The effects of DNLA were comparable to metformin. In summary, DNLA was effective in improving cognitive deficits in aged SAMP8 mice, possibly via suppression of ER stress-related PERK signaling pathway, sequential inhibition of calpain 1, GSK-3β and Cdk5 activities, and eventually reducing the hyper-phosphorylation of Tau.

Acupuncture improves locomotor activity and learning-memory ability by improving hippocampal cellular autophagy in rats with fetal intrauterine distress

To investigate the effect of acupuncture stimulation of head acupoints "Jin San Zhen" (JIN's Three Acupuncture Needles Therapy) on behavior reactions, hippocampal neuronal autophagy and expression of autophagy associated proteins (Beclin-1 and light chain 3 Ⅱ/Ⅰ [LC 3 Ⅱ/Ⅰ]) in rats with hypoxic-ischemic brain damage (HIBD) due to fetal intrauterine distress, so as to reveal its underlying mechanisms in improving neonatal HIBD. Pregnant SD rats were used in the present study. The HIBD model was established by delayed caesarean delivery and bilateral uterine arteries clipping for 10 minutes. The HIBD rats were randomly divided into model group and acupuncture groups (n＝9 rats in each group). The other 9 rats delivered naturally were used as the normal control group. On day 14 after delivery, the neonatal rats in the acupuncture group received acupuncture stimulation of head acupoints ("Nao San Zhen""Nie San Zhen" and "Zhi San Zhen") by twirling each needle leftward and rightward for 10 times, once a day for 14 d. The open field test and Morris water maze test were used to determine the locomotive activity and spatial learning-memory ability, respectively. The ultrastructure and autophagosomes in the hippocampal neurons were observed by transmission electron microscope. The contents and expression levels of Beclin-1 and LC3 Ⅱ/Ⅰ in the hippocampus tissues were detected by flow cytometry and Western blot, separately. Compared with the normal control group, the time to go out of the central region of open field test, and the escape latency and duration of first platform-quadrant-crossing of spatial exploration of Morris water maze tests were significantly increased (P<0.01，P<0.05，P<0.001), and the total distance and number of activities in the central region, and the target quadrant resistance time and number of platform-cros-sing remarkably decreased in the model group (P<0.01, P<0.05), suggesting a decline of both locomotor activity and learning-memory ability after modeling. The expression level (%) of Beclin-1 protein and ratio of LC3 Ⅱ/Ⅰ proteins were considerably increased in the model group (P<0.01). Following acupuncture interventions, the locomotor activity and spatial learning-memory ability were obviously increased (P<0.05，P<0.01，P<0.001), and the expression of Beclin-1 protein and ratio of LC3 Ⅱ/Ⅰ were further up-regulated relevant to the model group (P<0.001). Moreover, ultrastructural observation showed serrated change of nuclear membrane and widened perinuclear space, vacuolization in the mitochondria, dilation of endoplasmic reticulum and increase of autophagosomes in the hippocampal neurons in the model group. These situations were relatively milder in the acupuncture group. Acupuncture of head acupoints of "JIN San Zhen" may increase locomotor activity and learning-memory abi-lity in rats with HIBD due to fetal intrauterine anoxia, which is closely with its effect in promoting hippocampal neuronal autophagy via up-regulating the expression of Beclin-1 and LC3 Ⅱ/Ⅰ.

Role of B vitamins on Oxidative Stress and Apoptotic Proteins Expression in Experimental Colon Cancer Model

BackgroundAzoxymethane is a potent carcinogenic agent commonly used to induce colon cancer and oxidative stress in rats. The endoplasmic reticulum (ER) stress response, represents an adaptive mechanism to support cellular survival in response to adverse microenvironment conditions by accumulating misfolded proteins and leading to apoptosis of cells. GRP78 has the potency of (potential to) inhibiting apoptosis by blocking BAX activity and thereby switching off intrinsic apoptotic pathway. Clinical studies continue to stress that oxidative stress (GRP78) is mediated B‐vitamins (folate and B12) deficiencies, oxidative and hyper homocysteinemia. However, it is relatively unknown how B vitamins affect oxidative stress on colon cancer tissue.ObjectiveTo study the expression of GRP78 and apoptotic proteins on azoxymethane(AOM) induced colon cancer using B vitamins and also to see any ultrastructure changes using Electron Microscopy.MethodsAzoxymethane (AOM)‐induced colon cancer model was used in Sprague‐Dawley rats were randomly divided into groups. The control group fed a basal diet with no AOM injection; the AOM‐treated group fed a basal diet with AOM intraperitoneal injections, whereas the other experimental groups received daily doses of folate or vitamin B12 supplementation in the presence or absence of AOM injection. Another 6 groups of rats were tested for the potential synergistic effects of both folate and vitamin B12 supplementation. All animals continuously fed ad‐libitumuntil 16 weeks, then all rats were sacrificed and the colon tissues were examined for the immunohistochemical and ultrastructural changes. Briefly, 2–3mm of colon tissue sections were stored in glutaraldehyde and from these semithin and ultrathin sections were cut and viewed to delineate the cellular organelles architecture in a transmission electron microscope (TEM). Paraffin blocks were cut and the expression of GRP78, Bcl2 and Bax was observed under a light microscope using Immunohistochemistry (IHC) technique.ResultsThere was over expression of GRP78 , Bcl2 and Bax proteins on IHC in colon cancer tissues treated with B vitamins however their expression was dose dependent. There were also ultrastructure changes in the cell organelles with dilation of endoplasmic reticulum and increase in the number of mitochondria. This is consistent with our earlier finding that early exposure to AOM causes morphological changes in the colonic mucosa of the assayed groups.ConclusionVitamin B12 and folate play a protective role against oxidative stress at both the cellular and protein levels and might ameliorate the metabolic stress on colon cells caused by cancer. Overexpression of GRP78 and the role of B vitamins will help in future to study the UPR components for understanding the cellular mechanisms involved in cancer progression.Support or Funding InformationSQU Institutional Fund

Elevation of the unfolded protein response increases RANKL expression.

Increased production of the osteoclastogenic cytokine RANKL is a common feature of pathologic bone loss, but the underlying cause of this increase is poorly understood. The unfolded protein response (UPR) is activated in response to accumulation of misfolded proteins in the endoplasmic reticulum (ER). Failure to resolve misfolding results in excess UPR signaling that stimulates cytokine production and cell death. We therefore investigated whether RANKL is one of the cytokines stimulated in response to elevated UPR in bone cells. Pharmacologic induction of UPR with tunicamycin (Tm)‐stimulated RANKL expression in cultures of primary osteoblastic cells and in osteoblast and osteocyte cell lines. Pharmacologic inhibition of the UPR blunted Tm‐induced RANKL production. Silencing Edem1 or Sel1l, proteins that aid in degradation of misfolded proteins, also induced UPR and increased RANKL mRNA. Moreover, Tm or hypoxia increased RANKL and bone resorption in cultures of neonatal murine calvaria. Administration of Tm to adult mice caused dilation of ER in osteoblasts and osteocytes, elevated the UPR, and increased RANKL expression and osteoclast number. These findings support the hypothesis that excessive UPR signaling stimulates the expression of RANKL by osteoblasts and osteocytes, and thereby facilitates excessive bone resorption and bone loss in pathologic conditions.

Tissue-infiltrating macrophages mediate an exosome-based metabolic reprogramming upon DNA damage

DNA damage and metabolic disorders are intimately linked with premature disease onset but the underlying mechanisms remain poorly understood. Here, we show that persistent DNA damage accumulation in tissue-infiltrating macrophages carrying an ERCC1-XPF DNA repair defect (Er1F/−) triggers Golgi dispersal, dilation of endoplasmic reticulum, autophagy and exosome biogenesis leading to the secretion of extracellular vesicles (EVs) in vivo and ex vivo. Macrophage-derived EVs accumulate in Er1F/− animal sera and are secreted in macrophage media after DNA damage. The Er1F/− EV cargo is taken up by recipient cells leading to an increase in insulin-independent glucose transporter levels, enhanced cellular glucose uptake, higher cellular oxygen consumption rate and greater tolerance to glucose challenge in mice. We find that high glucose in EV-targeted cells triggers pro-inflammatory stimuli via mTOR activation. This, in turn, establishes chronic inflammation and tissue pathology in mice with important ramifications for DNA repair-deficient, progeroid syndromes and aging.

Alterations in characteristics of canine articular chondrocytes in non-passaged long-term monolayer culture: Matter of differentiation, dedifferentiation and redifferentiation.

This study investigated the effects of culture time on phenotype stability of canine articular chondrocytes (CACs) in non-passaged long-term monolayer culture. Third passage (P3) CACs isolated from four cartilage samples were seeded at three different initial seeding densities (0.2 × 104, 1.0 × 104 and 5.0 × 104 cells/cm2) and maintained in monolayer condition up to 8 weeks without undergoing subculture after confluence. The characteristic changes of chondrocytes during the culture period were evaluated based on the cell morphology, cell proliferation, glycosaminoglycans (GAGs) content, DNA quantification, mRNA expression and ultrastructure of chondrocytes. Chondrocytes maintained under post-confluence condition exhibited a capability to grow and proliferate up to 4 weeks. Alcian blue staining and Dimethylmethylene blue (DMMB) assay revealed that the extracellular matrix (ECM) synthesis was increased in a time-dependent manner from 2 to 8 weeks. The chondrocyte mRNA expression profile was dramatically affected by prolonged culture time, with a significant downregulation of collagen type I, whereas the expression of collagen type II, aggrecan, Sox9 and matrix metalloproteinase 13 (MMP-13) were significantly upregulated. In addition, transmission electron microscopy (TEM) result indicated dilation of rough endoplasmic reticulum (RER) in these long-term monolayer cultured chondrocytes. These findings demonstrate that the chondrocytes phenotype could be partially redifferentiated through the spontaneous redifferentiation process in long-term cultures using standard culture medium without the addition of chondrogenic supplements or tissue-culture scaffolds.

Catestatin improves insulin sensitivity by attenuating endoplasmic reticulum stress: In vivo and in silico validation

Obesity is characterized by a state of chronic, unresolved inflammation in insulin-targeted tissues. Obesity-induced inflammation causes accumulation of proinflammatory macrophages in adipose tissue and liver. Proinflammatory cytokines released from tissue macrophages inhibits insulin sensitivity. Obesity also leads to inflammation-induced endoplasmic reticulum (ER) stress and insulin resistance. In this scenario, based on the data (specifically patterns) generated by our in vivo experiments on both diet-induced obese (DIO) and normal chow diet (NCD) mice, we developed an in silico state space model to integrate ER stress and insulin signaling pathways. Computational results successfully followed the experimental results for both DIO and NCD conditions. Chromogranin A (CgA) peptide catestatin (CST: hCgA352-372) improves obesity-induced hepatic insulin resistance by reducing inflammation and inhibiting proinflammatory macrophage infiltration. We reasoned that the anti-inflammatory effects of CST would alleviate ER stress. CST decreased obesity-induced ER dilation in hepatocytes and macrophages. On application of Proportional-Integral-Derivative (PID) controllers on the in silico model, we checked whether the reduction of phosphorylated PERK resulting in attenuation of ER stress, resembling CST effect, could enhance insulin sensitivity. The simulation results clearly pointed out that CST not only decreased ER stress but also enhanced insulin sensitivity in mammalian cells. In vivo experiment validated the simulation results by depicting that CST caused decrease in phosphorylation of UPR signaling molecules and increased phosphorylation of insulin signaling molecules. Besides simulation results predicted that enhancement of AKT phosphorylation helps in both overcoming ER stress and achieving insulin sensitivity. These effects of CST were verified in hepatocyte culture model.

Lercanidipine Synergistically Enhances Bortezomib Cytotoxicity in Cancer Cells via Enhanced Endoplasmic Reticulum Stress and Mitochondrial Ca2+ Overload.

The proteasome inhibitor (PI), bortezomib (Btz), is effective in treating multiple myeloma and mantle cell lymphoma, but not solid tumors. In this study, we show for the first time that lercanidipine (Ler), an antihypertensive drug, enhances the cytotoxicity of various PIs, including Btz, carfilzomib, and ixazomib, in many solid tumor cell lines by inducing paraptosis, which is accompanied by severe vacuolation derived from the endoplasmic reticulum (ER) and mitochondria. We found that Ler potentiates Btz-mediated ER stress and ER dilation, possibly due to misfolded protein accumulation, in MDA-MB 435S cells. In addition, the combination of Btz and Ler triggers mitochondrial Ca2+ overload, critically contributing to mitochondrial dilation and subsequent paraptotic events, including mitochondrial membrane potential loss and ER dilation. Taken together, our results suggest that a combined regimen of PI and Ler may effectively kill cancer cells via structural and functional perturbations of the ER and mitochondria.

Non‐invasive, needle‐free drug delivery for treatment of retinal degeneration on Bardet‐Biedl syndrome

AbstractPurposeTo develop a non‐invasive drug delivery system based on superparamagnetic nanoparticles (NP) for the treatment of retinal degeneration on Bardet‐Biedl syndrome (BBS). The delivery system will be used to deliver two small molecules, valproic acid (VPA) and Guanabenz (GBZ).MethodsA mixture of two NP (one loaded with VPA and other with GBZ) was applied as eyedrops on 14‐days old mice with the use of a magnetic field. The treatment was assessed in both wild type and a mice model for BBS (Bbs12−/−). The effects of the treatment were evaluated 2 weeks post treatment at 1‐month‐old. Retinal structure and function were analysed using electroretinogram recordings (ERG), histology and transmission electron microscopy (TEM).ResultsIn vitro studies showed no important toxic effects in cell cultures for retinal pigmented epithelium (RPE1) and 661W (murine photoreceptor precursor) after treatment with unloaded NP. Scotopic and photopic ERG recordings showed no toxic effect of the NP on photoreceptor (PR) function. TEM analysis indicated the presence of the NP in the PR layer of the retina after eyedrop application. TEM images showed a decrease in Endoplasmic Reticulum (ER) dilatation. The treated group with loaded NP showed an increase in the thickness of the inner nuclear layer, outer nuclear layer, inner PR segment and outer PR segment.ConclusionsThese results highlight the potential for these NP for non‐invasive drug delivery to the retina. Both the presence of the NP and biological effect were shown in our mouse model. The VPA and GBZ combination has already shown decrease of cell death mediated by ER stress in the Bbs12−/− model. This is an unmet clinical need with no curative treatment for retinal ciliopathies. The possibility of delaying PR death would increase the therapeutic window of gene therapy potentially increasing its effectivity.

Human umbilical cord blood mononuclear cells protect against renal tubulointerstitial fibrosis in cisplatin-treated rats

Currently, there is no effective method to prevent renal interstitial fibrosis after acute kidney injury (AKI). In this study, we established and screened a new renal interstitial fibrosis rat model after cisplatin-induced AKI. Our results indicated that rats injected with 4 mg/kg cisplatin once a week for two weeks after firstly administrated with 6.5 mg/kg loading dose of cisplatin could set up a more accurate model reflecting AKI progression to renal interstitial fibrosis. Then, we investigated the effects and possible mechanisms of human umbilical cord blood mononuclear cells (hUCBMNCs) on renal tubular interstitial fibrosis after cisplatin-induced AKI. In rats injected with hUCBMNCs for four times, level of matrix metalloproteinase 7 (MMP-7) in serum and urine, urinary albumin/creatinine ratio, tubular pathological scores, the relative collagen area of the tubulointerstitial region, endoplasmic reticulum dilation and the mitochondrial ultrastructural damage were significantly improved. The level of reactive oxygen species, α-smooth muscle actin (α-SMA), [NOD]-like pyrin domain containing protein 3 and cleaved-Caspase 3 in renal tissue decreased significantly. However, in rats injected with hUCBMNCs for two times, no significant difference was discovered in MMP-7 levels and urinary albumin/creatinine ratio. Although expression of α-SMA and the percentage areas of collagen staining in tubulointerstitial tissues were ameliorated in rats injected with hUCBMNCs for two times, the effects were significantly weaker than those in rats injected with hUCBMNCs for four times. Taken together, our study constructed a highly efficient, duplicable novel rat model of renal fibrosis after cisplatin-induced AKI. Multiple injections of hUCBMNCs may prevent renal interstitial fibrosis after cisplatin-induced AKI.

Human umbilical cord blood mononuclear cells protect against renal tubulointerstitial fibrosis in cisplatin-treated rats

Currently, there is no effective method to prevent renal interstitial fibrosis after acute kidney injury (AKI). In this study, we established and screened a new renal interstitial fibrosis rat model after cisplatin-induced AKI. Our results indicated that rats injected with 4 mg/kg cisplatin once a week for two weeks after firstly administrated with 6.5 mg/kg loading dose of cisplatin could set up a more accurate model reflecting AKI progression to renal interstitial fibrosis. Then, we investigated the effects and possible mechanisms of human umbilical cord blood mononuclear cells (hUCBMNCs) on renal tubular interstitial fibrosis after cisplatin-induced AKI. In rats injected with hUCBMNCs for four times, level of matrix metalloproteinase 7(MMP-7)in serum and urine, urinary albumin/creatinine ratio, tubular pathological scores, the relative collagen area of the tubulointerstitial region, endoplasmic reticulum dilation and the mitochondrial ultrastructural damage were significantly improved. The level of reactive oxygen species, α-smooth muscle actin (α-SMA), [NOD]-like pyrin domain containing protein 3 and cleaved-Caspase 3 in renal tissue decreased significantly. However, in rats injected with hUCBMNCs for two times, no significant difference was discovered in MMP-7 levels and urinary albumin/creatinine ratio. Although expression of α-SMA and the percentage areas of collagen staining in tubulointerstitial tissues were ameliorated in rats injected with hUCBMNCs for two times, the effects were significantly weaker than those in rats injected with hUCBMNCs for four times. Taken together, our study constructed a highly efficient, duplicable novel rat model of renal fibrosis after cisplatin-induced AKI. Multiple injections of hUCBMNCs may prevent renal interstitial fibrosis after cisplatin-induced AKI.

Pro-inflammatory effect induced by endoplasmic reticulum stress in placental trophoblast cells participates in genesis of gestational diabetes mellitus

Objective To explore whether the pro-inflammatory effect of endoplasmic reticulum stress in placental tissues involves in the genesis of gestational diabetes mellitus (GDM). Methods Forty gravidas who underwent regular prenatal examinations and delivered at Tongji Hospital were recruited from January to December, 2016. Among them, 20 were GDM women (GDM group), and the remaining twenty were served as the control, which were selected from those without GDM and matched for age and gestational weeks to the GDM group. Placental tissues were collected from the two groups. The ultrastructure of endoplasmic reticulum in trophoblast cells was observed under transmission electron microscope. The expression of glucose-regulated protein-78 (GRP-78), a marker protein for endoplasmic reticulum stress, and C/EBP homologous protein (CHOP) were detected using Western blotting. Five placental tissue samples were collected from normal gravidas for explant culture. Three subgroups were set up according to different culturing methods including culturing with IL-1β (5 ng/ml) for 20 h (IL-1β model group), 30 μmol/L thapsigargin (TG, an endoplasmic reticulum stress agonist) for 2 h after treating with IL-1β (5 ng/ml) for 18 h (IL-1β+TG intervention group) or with no stimulation (blank control group). Western blotting was used to detect the expressions of GRP-78, CHOP and glucose transporter 4 (GLUT4) in placenta explants. The mRNA expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined by real-time fluorescence quantitative polymerase chain reaction (RT-PCR). Statistical analysis was performed using one-way analysis of variance, LSD and t test. Results (1) In the GDM group, increased number and size of endoplasmic reticulum cisternae were observed in trophoblast cells. Moreover, obviously dilated endoplasmic reticulum and different size of fragments and vesicles were also seen under electron microscope. While the endoplasmic reticulum in the placental tissues of the control group showed no obvious swelling. (2) The expression of GRP-78 and CHOP protein in the GDM group were higher than those in the control group (0.90±0.17 vs 0.48±0.08, t=2.24; 0.85±0.13 vs 0.46±0.12, t=2.10; both P<0.05). (3) Compared with the blank control group, the expression of GRP-78 and CHOP protein in the IL-1β model group increased significantly (0.87±0.18 vs 0.36±0.07, t=2.67; 1.14±0.09 vs 0.78±0.06, t=3.20; both P<0.05); but the expression of GLUT4 protein significantly decreased (1.00±0.14 vs 2.21±0.49, t=2.40, P<0.05); the expressions of IL-6 and TNF-α mRNA significantly increased (0.89±0.23 vs 0.30±0.06, t=2.31; 0.62±0.16 vs 0.17±0.09, t=2.29; both P<0.05). Compared with the IL-1β model group, the expression of GRP-78 and CHOP protein significantly increased in IL-1β+TG group (2.02±0.32 vs 0.87±0.18, t=3.11; 2.18±0.31 vs 1.14±0.09, t=3.16; both P<0.05); the expression of GLUT4 protein significantly decreased (0.39±0.19 vs 1.00±0.14, t=2.66, P<0.05); the expression of IL-6 and TNF-α mRNA increased significantly (1.67±0.25 vs 0.89±0.23, t=2.26; 1.42±0.27 vs 0.62±0.16, t=2.51; both P<0.05). Conclusions Endoplasmic reticulum stress may be associated with increased release of pro-inflammatory cytokines in placental tissues of some GDM women and involved in the onset and development of GDM. Key words: Diabetes, gestational; Endoplasmic reticulum stress; Placenta; Cytokines; Inflammation

Vitamin E protects against monosodium glutamate-induced acute liver injury and hepatocyte ultrastructural alterations in rats

ABSTRACTFood additives such as nitrates and nitrites, and monosodium glutamate (MSG) used in the food industry increase the risk of certain cancers and inflict damage to vital organs. We sought to determine whether the antioxidant vitamin E can protect against liver injuries induced by a toxic dose of MSG in a rat model of MSG-induced acute liver injury. The model group of rats received a daily dose of MSG (4 gm/kg) for 7 days, whereas the protective groups were either received a 100 mg/kg vitamin E plus MSG or 300 mg/kg vitamin E plus MSG for 7 days. Rats were then sacrificed at day 8. Transmission and light microscopy images revealed substantial liver tissue damage induced by MSG in the model group as demonstrated by apoptotic hepatocytes with Pyknotic nuclei and irregular nuclear membrane, and cytoplasm displayed many vacuoles, swollen mitochondria, dilated endoplasmic reticulum, dilated blood sinusoids and bundles of collagen fibers in extracellular space. Treatment of the model group with vitamin E showed a substantial protection of liver tissue and hepatocellular architecture by 300 mg/kg vitamin E compared to a partial protection by 100 mg/kg vitamin E. In addition, MSG significantly (p < .05) modulated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione peroxidase (GPx), which were significantly (p < .05) protected with vitamin E. Thus, vitamin E at 300 mg/kg effectively protects against MSG-induced acute liver injury in rats, possibly via the inhibition of inflammation, and up-regulation of endogenous antioxidants.

Palmitic Acid-Enriched Diet Induces Hepatic Steatosis and Injury in Adult Zebrafish.

Palmitic acid (PA) is the most abundant saturated fatty acid in fast foods and is known to induce inflammation and cellular injury in various tissues. In this study, we investigated whether a PA-enriched diet can induce hepatic steatosis and injury in adult zebrafish. The adult zebrafish exhibited increased body weight, hyperlipidemia, hyperglycemia, and steatosis and a hepatic injury phenotype after being fed with a PA-enriched diet for 6 weeks. The quantitative polymerase chain reaction analysis demonstrated that genes associated with hepatic injury were all significantly increased in the liver. Furthermore, livers from the PA-fed group showed an increased messenger RNA (mRNA) expression associated with oxidative stress and endoplasmic reticulum (ER) stress responses. We also found significant upregulation of genes involved in lipid metabolism and triacylglyceride accumulation. Ultrastructural analysis revealed mitochondrial cristae injury and a dilated ER phenotype in the PA-fed hepatocytes, which can be causes of hepatic injury. PA-enriched diet induced hepatic steatosis and injury in adult zebrafish that recapitulated typical metabolic changes and pathophysiological changes as well as increased oxidative stress and ER stress observed in patients with nonalcoholic fatty liver disease.

P2B.17: A model to study ischemia-reperfusion injury in human intestinal organoids

Introduction: Ischemia-reperfusion (IR) injury is inevitable during intestinal transplantation. IR damages the intestinal epithelium, which functions as a physical and immunological barrier and is therefore crucial in maintaining intestinal homeostasis. In order to investigate potential therapeutic targets to protect the epithelium during intestinal IR and promote a regenerative response, we aim to validate a model to study IR in human intestinal organoids. Intestinal organoids have been shown to closely resemble self-renewal kinetics, 3D architecture, and cell-type composition of the intestinal epithelium in vivo. Methods: A well-established human experimental model to study IR was used for temporal expression profiling of the in vivo intestinal response to IR. The top perturbed pathway was further validated using qPCR. Intestinal epithelial organoids were cultured from crypts isolated from surgical specimens of normal human small intestine. To simulate IR, organoids were subjected to 12 hours of hypoxia (1% O2) followed by 30 and 120 minutes of reoxygenation. Activation of the UPR response was assessed by qPCR for CHOP, GADD34, BiP and XBP1 splicing, and, in addition, signs of endoplasmic reticulum (ER) stress were evaluated using electron microscopy (EM). Results: The unfolded protein response (UPR) was the top perturbed pathway during reperfusion of the ischemically injured human small intestine in vivo. Subjecting small intestinal organoids to 12 hours of hypoxia followed by 30 minutes of reoxygenation significantly increased expression of UPR-related genes CHOP and GADD34 and splicing of XBP1 mRNA compared to organoids not subjected to hypoxia. In addition, EM showed dilated ER after reoxygenation which is indicative of ER stress. Conclusion: In line with findings in the in vivo human IR model, revealing the response to unfolded protein as a highly regulated process during reperfusion, hypoxia-reoxygenation in intestinal organoids induces significant activation of the UPR. Intestinal organoids can be used to improve insight in the pathophysiology of epithelial IR injury and regeneration, which could lead to new therapeutic targets.

Combustion- and friction-derived magnetic air pollution nanoparticles in human hearts

Air pollution is a risk factor for cardiovascular and Alzheimer's disease (AD). Iron-rich, strongly magnetic, combustion- and friction-derived nanoparticles (CFDNPs) are abundant in particulate air pollution. Metropolitan Mexico City (MMC) young residents have abundant brain CFDNPs associated with AD pathology. We aimed to identify if magnetic CFDNPs are present in urbanites' hearts and associated with cell damage. We used magnetic analysis and transmission electron microscopy (TEM) to identify heart CFDNPs and measured oxidative stress (cellular prion protein, PrPC), and endoplasmic reticulum (ER) stress (glucose regulated protein, GRP78) in 72 subjects age 23.8 ± 9.4y: 63 MMC residents, with Alzheimer Continuum vs 9 controls. Magnetite/maghemite nanoparticles displaying the typical rounded crystal morphologies and fused surface textures of CFDNPs were more abundant in MMC residents' hearts. NPs, ∼2–10 × more abundant in exposed vs controls, were present inside mitochondria in ventricular cardiomyocytes, in ER, at mitochondria-ER contact sites (MERCs), intercalated disks, endothelial and mast cells. Erythrocytes were identified transferring ‘hitchhiking’ NPs to activated endothelium. Magnetic CFDNP concentrations and particle numbers ranged from 0.2 to 1.7 μg/g and ∼2 to 22 × 109/g, respectively. Co-occurring with cardiomyocyte NPs were abnormal mitochondria and MERCs, dilated ER, and lipofuscin. MMC residents had strong left ventricular PrPC and bi-ventricular GRP78 up-regulation.The health impact of up to ∼22 billion magnetic NPs/g of ventricular tissue are likely reflecting the combination of surface charge, ferrimagnetism, and redox activity, and includes their potential for disruption of the heart's electrical impulse pathways, hyperthermia and alignment and/or rotation in response to magnetic fields. Exposure to solid NPs appears to be directly associated with early and significant cardiac damage. Identification of strongly magnetic CFDNPs in the hearts of children and young adults provides an important novel layer of information for understanding CVD pathogenesis emphasizing the urgent need for prioritization of particulate air pollution control.

The effect of various durations of cigarette smoke exposure on muscle fibre remodeling in rat diaphragms

Chronic obstructive pulmonary disease (COPD) often causes diaphragm dysfunction, which is the main contributor to neuro-muscular respiratory failure and associated with the prognosis of COPD. However, the morphological changes in diaphragm during the development of COPD are complicated and underlying mechanisms have not been absolutely elucidated. Considering smoking is one of the most leading and important risk factors for development of COPD, we set out to investigate the effects of smoking on muscle fibre remodeling and underlying mechanisms in diaphragms. Rats were randomly exposed to cigarette smoke (CS) for one of three durations of 4, 8, and 12 weeks. CS exposure resulted in increased percentage of type I muscle fibres, enhanced apoptosis index, endoplasmic reticulum (ER) dilation, elevated expression of glucose-regulated protein 78, C/EBP homologous protein, caspase-12, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), cytochrome c oxidase 4, Sdhb, p53 and a reduction in fibre diameters in rat diaphragms. The results indicated that CS exposure induced a shift to muscle fibres with aerobic metabolism in predominance in rat diaphragms, which may be dependent on the regulation of PGC-1α and p53. Additionally, ER stress (ERS) associated apoptosis may contribute to the pathogenesis of diaphragmatic muscle atrophy induced by CS exposure.

Acute Toxicity of Divalent Mercury Ion to Anguilla japonica from Seawater and Freshwater Aquaculture and Its Effects on Tissue Structure.

The acute toxicity of divalent mercury ion to Anguilla japonica from seawater and freshwater aquaculture was assessed. In particular, the effects of toxicity on the microstructures of the gill and liver tissues were examined using the hydrostatic method, without feeding, at a water temperature of 20 °C. The median lethal concentrations (LC50) of divalent mercury ion to fishes in seawater and freshwater over various durations were: 24 h = 1.637 and 1.428 mg/L; 48 h = 1.562 and 1.377 mg/L; 72 h = 1.530 and 1.284 mg/L; and 96 h = 1.442 and 1.228 mg/L. The safety mass concentrations were 0.1442 and 0.01228 mg/L, respectively. After exposure to divalent mercury ion, adhesion between the gill lamellae and massive cellular disintegration and necrotic shedding were observed in the gill tissue sections. The liver tissues underwent hyperemia and swelling, with the appearance of blood spots, swelling of the hepatocyte mitochondria, dilation of the rough endoplasmic reticulum, and intercellular inflation.

A histological, immunohistochemical and biochemical study of the effects of pomegranate peel extracts on gibberellic acid induced oxidative stress in adult rat testes

ABSTRACTGibberellins are commonly used plant growth regulators that exhibit deleterious effects on various animal tissues. We investigated the histological, immunohistochemical and biochemical effects of gibberellic acid (GA3) on rat testes as well as the possible protective role of pomegranate peel extract (PPE). We used 28 adult male rats divided into control, PPE treated, GS3 treated and GA3 + PPE treated groups. Testis specimens were analyzed for superoxide dismutase (SOD) and catalase (CAT) activity, and examined histologically. We also investigated the androgen receptor using immunohistochemistry. The GA3 treated group exhibited significantly decreased SOD and CAT levels and area percent of androgen receptor. Seminiferous tubules (ST) were widely separated and the germinal epithelium was separated from the basement membrane in some tubules. Areas of vacuolation, degenerated germ cells with pyknotic nuclei and large multinucleated cells were observed. Ultrastructurally, primary spermatocytes exhibited vacuolated cytoplasm, degenerated mitochondria and hyperchromatic nuclei. Degenerated early spermatids with a ruptured or hyperchromatic nucleus were found. Spermatozoa exhibited abnormalities of the head and tail. The cytoplasm of Sertoli and Leydig cells exhibited dilated smooth endoplasmic reticulum. A significant improvement of the biochemical, histological and immunohistochemical alterations was observed in the GA3 + PPE treated group compared to the GA3 treated group.