Identification of a natural PLA2 inhibitor from the marine fungus Aspergillus sp. c1 for MAFLD treatment that suppressed lipotoxicity by inhibiting the IRE-1α/XBP-1s axis and JNK signaling

Lipotoxicity is a pivotal factor that initiates and exacerbates liver injury and is involved in the development of metabolic-associated fatty liver disease (MAFLD). However, there are few reported lipotoxicity inhibitors. Here, we identified a natural anti-lipotoxicity candidate, HN-001, from the marine fungus Aspergillus sp. C1. HN-001 dose- and time- dependently reversed palmitic acid (PA)-induced hepatocyte death. This protection was associated with IRE-1α-mediated XBP-1 splicing inhibition, which resulted in suppression of XBP-1s nuclear translocation and transcriptional regulation. Knockdown of XBP-1s attenuated lipotoxicity, but no additional ameliorative effect of HN-001 on lipotoxicity was observed in XBP-1s knockdown hepatocytes. Notably, the ER stress and lipotoxicity amelioration was associated with PLA2. Both HN-001 and the PLA2 inhibitor MAFP inhibited PLA2 activity, reduced lysophosphatidylcholine (LPC) level, subsequently ameliorated lipotoxicity. In contrast, overexpression of PLA2 caused exacerbation of lipotoxicity and weakened the anti-lipotoxic effects of HN-001. Additionally, HN-001 treatment suppressed the downstream pro-apoptotic JNK pathway. In vivo, chronic administration of HN-001 (i.p.) in mice alleviated all manifestations of MAFLD, including hepatic steatosis, liver injury, inflammation, and fibrogenesis. These effects were correlated with PLA2/IRE-1α/XBP-1s axis and JNK signaling suppression. These data indicate that HN-001 has therapeutic potential for MAFLD because it suppresses lipotoxicity, and provide a natural structural basis for developing anti-MAFLD candidates.

A novel defined risk signature of endoplasmic reticulum stress-related genes for predicting the prognosis and immune infiltration status of ovarian cancer / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Endoplasmic reticulum (ER) stress, as an emerging hallmark feature of cancer, has a considerable impact on cell proliferation, metastasis, invasion, and chemotherapy resistance. Ovarian cancer (OvCa) is one of the leading causes of cancer-related mortality across the world due to the late stage of disease at diagnosis. Studies have explored the influence of ER stress on OvCa in recent years, while the predictive role of ER stress-related genes in OvCa prognosis remains unexplored. Here, we enrolled 552 cases of ER stress-related genes involved in OvCa from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts for the screening of prognosis-related genes. The least absolute shrinkage and selection operator (LASSO) regression was applied to establish an ER stress-related risk signature based on the TCGA cohort. A seven-gene signature revealed a favorable predictive efficacy for the TCGA, International Cancer Genome Consortium (ICGC), and another GEO cohort (P<0.001, P<0.001, and P=0.04, respectively). Moreover, functional annotation indicated that this signature was enriched in cellular response and senescence, cytokines interaction, as well as multiple immune-associated terms. The immune infiltration profiles further delineated an immunologic unresponsive status in the high-risk group. In conclusion, ER stress-related genes are vital factors predicting the prognosis of OvCa, and possess great application potential in the clinic.

Phosphodiesterase 5 Inhibitors Attenuate Unilateral Ureteral Obstruction-Induced Renal Fibrosis / 中山大学学报(医学科学版)

ObjectiveTo investigate whether phosphodiesterase （PDE） 5 inhibitors sildenafil （SIL） or LW1646 prevented renal interstitial fibrosis induced by unilateral ureteral obstruction （UUO）. MethodsMale C57BL/6 mice were randomly divided into four groups （n =6）， namely the Sham group， 7UUO group， 7UUO+SIL group and 7UUO+LW1646 group. Sildenafil （SIL） or LW1646， or vehicle was administered 1 hour before surgery， and the mice were continuously treated once daily （i. g.， 50 mg/kg） for 7 days. The obstructed kidneys were harvested on day 7. Hematoxylin-eosin （HE） and Masson’s staining was used to examine renal histology. Immunoblotting and RT-qPCR were used to detect the expression levels of protein and mRNA for fibrosis， apoptosis， endoplasmic reticulum （ER） stress， autophagy， and pro-fibrotic factors. Human proximal tubule epithelial cells （HK-2） were treated with TGF-β1 for 48 hours or tunicamycin for 24 hours， respectively， to evaluate whether cyclic guanosine monophosphate （cGMP） or PDE5 inhibitors prevents ER stress and pro-fibrotic responses. ResultsAt the 7th days after UUO， the body weight of the mice showed a significant decrease （P< 0.000 1） compared with that in the sham group. The obstructed kidneys showed a significant tubular dilation and interstitial inflammation. The levels of protein and mRNA expression in apoptosis， ER stress， autophagy-related protein and pro-fibrotic factors were also markedly increased in UUO mice （P <0.05）. In contrast， SIL or LW1646 treatment was associated with attenuated tubular dilation， infiltration of inflammatory cells and collagen content in the obstructed kidney of the mice. The protein and mRNA expression levels of renal TGF-β1 were markedly decreased， and the protein expression levels of apoptosis， endoplasmic reticulum stress， and autophagy markers were also significantly downregulated by PDE5 inhibitors. In HK-2 cells， TGF-β1 induced increased expression levels of fibronectin and BiP， which was at least partially reversed by cGMP， a product of PDE inhibition. Additionally， PDE5 inhibitors were found to modulate aberrant levels of autophagy and apoptosis. ConclusionIn conclusion， PDE5 inhibitors， in particular， LW1646， can alleviate the progression of fibrosis by improving ER stress， apoptosis and autophagy as well as downregulating protein and mRNA expression of TGF-β1.

Transcriptome Analysis of Entamoeba histolytica Trophozoites during in vivo Contact-independent Mediated Host-parasite Interaction: Putative Pathways Related to PCD

Aim: In the present study, we exploited DNA microarray-based transcriptome analysis and showed overall changes in gene expression in vivo of amoebic trophozoites that interact with animal soluble factors using an intraperitoneal dialysis bag model to elucidate putative molecular pathways and genes involved in this interaction. Study Design: We exploited DNA microarray-based transcriptome analysis. Results: An analysis from a network including the interactions of up-regulated genes and their neighbors revealed the presence of 11 functionally related modules. Six of the modules obtained were related to endoplasmic reticulum (ER) functions, such as degradation, stress, proteasome-ubiquitination, phosphorylation, lipid metabolism, and protein sorting. Furthermore, major transcriptional changes displayed by the parasite at the beginning of interaction were attributed to the response to the host defense. These data are consistent with the notion that the concerted expression of genes necessary for survival such as increment in protein synthesis, cytoskeleton rearrangement, vesicular traffic and genes involved in cell death including calcium imbalance and the ER signals associated with protein degradation (ERAD) is an overall landscape during the in vivo interaction between the amoebic trophozoites and animal soluble factors, and suggest that the ER stress is one of the main pathways leading to programmed cell death in E. histolytica. Conclusion: The present findings on the global transcriptional changes displayed by the parasite at the early stages of interaction with host environments in peritoneal implantation indicate that a substantial proportion of concerted changes in gene expression in amoebic trophozoites are attributable to the parasite’s response for cell death signals due to ER stress. A detailed knowledge of the underlying molecular mechanism might suggest the efficient elimination of this parasite by promoting their death pathways.

The novel ER stress inducer Sec C triggers apoptosis by sulfating ER cysteine residues and degrading YAP via ER stress in pancreatic cancer cells

Pancreatic adenocarcinoma (PAAD) is one of the most lethal malignancies. Although gemcitabine (GEM) is a standard treatment for PAAD, resistance limits its application and therapy. Secoemestrin C (Sec C) is a natural compound from the endophytic fungus Emericella, and its anticancer activity has not been investigated since it was isolated. Our research is the first to indicate that Sec C is a broad-spectrum anticancer agent and could exhibit potently similar anticancer activity both in GEM-resistant and GEM-sensitive PAAD cells. Interestingly, Sec C exerted a rapid growth-inhibiting effect (80% death at 6 h), which might be beneficial for patients who need rapid tumor shrinkage before surgery. Liquid chromatography/mass spectrometry and N-acetyl-l-cysteine (NAC) reverse assays show that Sec C sulfates cysteines to disrupt disulfide-bonds formation in endoplasmic reticulum (ER) proteins to cause protein misfolding, leading to ER stress and disorder of lipid biosynthesis. Microarray data and subsequent assays show that ER stress-mediated ER-associated degradation (ERAD) ubiquitinates and downregulates YAP to enhance ER stress via destruction complex (YAP-Axin-GSK-βTrCP), which also elucidates a unique degrading style for YAP. Potent anticancer activity in GEM-resistant cells and low toxicity make Sec C a promising anti-PAAD candidate.

Ameliorative Effect of miR-31 on Liver Injury in Type 2 Diabetic Mice / 中国生物化学与分子生物学报

Type 2 diabetes mellitus (T2DM) is a metabolic disease with an increasing incidence worldwide, which leads to damage to various tissues and organs including the liver. MiR-31 is conserved across species and closely associated with metabolic diseases, but its role in type 2 diabetic liver injury has not been elucidated. This study aimed to investigate the effect of miR-31 on liver injury in type 2 diabetes and its underlying mechanism. Four to six weeks old male FVB mice and miR-31-positive transgenic mice were randomly divided into FVB mice control group (C), FVB mice induced diabetes group (DM) and miR-31-overexpression transgenic mice induced diabetes group (31DM). After 1 week of adaptive feeding, the T2DM mouse model was induced by high-fat feeding combined with intraperitoneal injection of streptozotocin (STZ) for 6 weeks. The general condition of mice and related metabolic indicators showed that the increased food and water intake, weight loss and glucose and lipid metabolism disorders could be reversed by miR-31 in T2DM mice. HE staining and liver histological activity index (HAI) scoring results showed that miR-31 improved the inflammatory status in the liver tissue of T2DM mice and decreased the HAI score. RT-qPCR results showed that the high expression of miR-31 was accompanied by a decrease in the expression of activating transcription factor 6 (ATF6) mRNA in the liver of T2DM mice. Furthermore, Western blotting results showed that miR-31 inhibited the expression of endoplasmic reticulum stress-related proteins such as ATF6, glucoregulatory protein 78 (GRP78) and C/EBP homologous protein (CHOP) in the liver of T2DM mice. In conclusion, miR-31 may ameliorate liver injury in T2DM mice by regulating glucose and lipid metabolism disorders and insulin resistance, and inhibiting endoplasmic reticulum stress factors such as ATF6, GRP78, and CHOP.

Pristane induces autophagy in rat macrophages through endoplasmic reticulum stress / 西安交通大学学报(医学版)

【Objective】 To investigate the mechanism of pristane inducing autophagy in macrophages. 【Methods】 Pristane was used to stimulate NR8383， a rat macrophage cell line. The changes in signaling pathways of AMPK， mTOR， and endoplasmic reticulum （ER） stress pathways including eIF2α and IRE1α in the cell model， as well as the expression of transcriptional factor TFEB and its translocation to the nucleus， were detected by using Western blotting. ER stress pathways were intervened by using an inducer DTT or an inhibitor 4-PBA to determin its effect on mTOR expression and autophay. 【Results】 In pristane-stimulated NR8383 cell model， ER stress pathway eIF2α was activated at 0.5 h after stimulation， and then mTOR expression was decreased at 1 and 3 h after stimulation. There was no change for AMPK and IRE1α pathways. With 4-PBA treatment， pristane-reduced mTOR expression and increased LC3-II were reversed， while with DTT treatment， mTOR expression decreased and LC3-II expression increased even more. Pristane induced the expression and activation of TFEB in NR8383 cells. 【Conclusion】 Pristane induces ER stress and leads to autophagy enhancement in rat macrophages.

Review of literature on Akkermansia muciniphila and its possible role in the Etiopathogenesis and Therapy of Type 2 Diabetes Mellitus / Journal of the ASEAN Federation of Endocrine Societies

@#Akkermansia muciniphila is a promising gut microbiota for the treatment of type 2 diabetes mellitus (T2DM). A. muciniphilastimulates intestinal wall integrity, is an anti-inflammatory agent, and reduces endoplasmic reticulum stress, lipogenesis and gluconeogenesis. These properties make A. muciniphila a potential treatment option for T2DM by reducing insulin resistance and increasing insulin sensitivity and glucose tolerance in different tissues. This article explores the possible role of A. muciniphila in T2DM management, along with the various methods known to modulate A. muciniphila.

Demethylzeylasteral (T-96) initiates extrinsic apoptosis against prostate cancer cells by inducing ROS-mediated ER stress and suppressing autophagic flux

BACKGROUND: Demethylzeylasteral (T-96) is a pharmacologically active triterpenoid monomer extracted from Tripterygium wilfordii Hook F (TWHF) that has been reported to exhibit anti-neoplastic effects against several types of cancer cells. However, the potential anti-tumour effects of T-96 against human Prostate cancer (CaP) cells and the possible underlying mechanisms have not been well studied. RESULTS: In the current study, T-96 exerted significant cytotoxicity to CaP cells in vitro and induced cell cycle arrest at S-phase in a dose-dependent manner. Mechanistically, T-96 promoted the initiation of autophagy but inhibited autophagic flux by inducing ROS-mediated endoplasmic reticulum (ER) stress which subsequently activated the extrinsic apoptosis pathway in CaP cells. These findings implied that T-96-induced ER stress activated the caspase-dependent apoptosis pathway to inhibit proliferation of CaP cells. Moreover, we observed that T-96 enhances the sensitivity of CaP cells to the chemotherapeutic drug, cisplatin. CONCLUSIONS: Taken together, our data demonstrated that T-96 is a novel modulator of ER stress and autophagy, and has potential therapeutic applications against CaP in the clinic.

Discovery of a small molecule inhibitor of cullin neddylation that triggers ER stress to induce autophagy

Protein neddylation is catalyzed by a three-enzyme cascade, namely an E1 NEDD8-activating enzyme (NAE), one of two E2 NEDD8 conjugation enzymes and one of several E3 NEDD8 ligases. The physiological substrates of neddylation are the family members of cullin, the scaffold component of cullin RING ligases (CRLs). Currently, a potent E1 inhibitor, MLN4924, also known as pevonedistat, is in several clinical trials for anti-cancer therapy. Here we report the discovery, through virtual screening and structural modifications, of a small molecule compound HA-1141 that directly binds to NAE in both

Effect of psoralen on rat osteoblasts injuries induced by TCP wear particles in vitro and its mechanism / 中国应用生理学杂志

To investigate the effect and mechanism of psoralen on calvarial osteoblasts injuries caused by tricalcium phosphate (TCP) wear particles in vitro. Primary osteoblasts were obtained from the calvaria of neonatal SD rat by the series of digestion and were identified with ALP staining. Calvarial osteoblasts were treated with TCP wear particles for 48 h to establish the in vitro model of osteoblasts injuries. The rat osteoblasts were randomly divided into control group, TCP wear particles (0.1 mg/ml) group, psoralen treated (at the concentrations of 10, 10, 10 mol/L) groups. WST assay and the flow cytometry were used to detect the cell viability of osteoblasts and apoptosis, respectively. Chemical colorimetry was performed to examine ALP activity of osteobalsts. When the osteoblasts were treated for 14 day, mineral nodules formation was observed with alizarin red S staining. Western blot was applied to examine protein expressions of glucose regulated protein78/94(GRP78/94), inositol dependent enzyme 1 alpha (IREα), spliced X-box binding protein 1 (XBP1s) and phosphorylated c-Jun N-terminal kinase (p-JNK) in calvarial osteoblasts. Compared with control group, the cell viability of osteoblasts, ALP activity and mineral nodules formation in TCP group were decreased significantly (P＜0.05), while the percentage of apoptosis and protein expressions of GRP78/94, IRE1α, XBP1 and p-JNK were obviously increased in calvarial osteoblasts (P＜0.05). Compared with TCP group, the injuries of calvarial osteoblasts and cell apoptosis in psoralen treated groups were obviously decreased (P＜0.05), and the expression levels of GRP78/94, IRE1α, XBP1 and p-JNK were down-regulated remarkably (P＜0.05). Psoralen prevents osteoblasts injuries caused by TCP wear particles through IRE1α-XBP1s-JNK signaling pathway activation.

Pilea umbrosa ameliorate CCl induced hepatic injuries by regulating endoplasmic reticulum stress, pro-inflammatory and fibrosis genes in rat

BACKGROUND@#Pilea umbrosa (Urticaceae) is used by local communities (district Abbotabad) for liver disorders, as anticancer, in rheumatism and in skin disorders.@*METHODS@#Methanol extract of P. umbrosa (PUM) was investigated for the presence of polyphenolic constituents by HPLC-DAD analysis. PUM (150 mg/kg and 300 mg/kg) was administered on alternate days for eight weeks in rats exposed with carbon tetrachloride (CCl). Serum analysis was performed for liver function tests while in liver tissues level of antioxidant enzymes and biochemical markers were also studied. In addition, semi quantitative estimation of antioxidant genes, endoplasmic reticulum (ER) induced stress markers, pro-inflammatory cytokines and fibrosis related genes were carried out on liver tissues by RT-PCR analysis. Liver tissues were also studied for histopathological injuries.@*RESULTS@#Level of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and glutathione (GSH) decreased (p < 0.05) whereas level of thiobarbituric acid reactive substance (TBARS), HO and nitrite increased in liver tissues of CCl treated rat. Likewise increase in the level of serum markers; alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and total bilirubin was observed. Moreover, CCl caused many fold increase in expression of ER stress markers; glucose regulated protein (GRP-78), x-box binding protein1-total (XBP-1 t), x-box binding protein1-unspliced (XBP-1 u) and x-box binding protein1-spliced (XBP-1 s). The level of inflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) was aggregated whereas suppressed the level of antioxidant enzymes; γ-glutamylcysteine ligase (GCLC), protein disulfide isomerase (PDI) and nuclear erythroid 2 p45-related factor 2 (Nrf-2). Additionally, level of fibrosis markers; transforming growth factor-β (TGF-β), Smad-3 and collagen type 1 (Col1-α) increased with CCl induced liver toxicity. Histopathological scrutiny depicted damaged liver cells, neutrophils infiltration and dilated sinusoids in CCl intoxicated rats. PUM was enriched with rutin, catechin, caffeic acid and apigenin as evidenced by HPLC analysis. Simultaneous administration of PUM and CCl in rats retrieved the normal expression of these markers and prevented hepatic injuries.@*CONCLUSION@#Collectively these results suggest that PUM constituted of strong antioxidant chemicals and could be a potential therapeutic agent for stress related liver disorders.

Sangguayin preparation prevents palmitate-induced apoptosis by suppressing endoplasmic reticulum stress and autophagy in db/db mice and MIN6 pancreatic β-cells / 中国天然药物

Sangguayin preparation (SGY-P) is refined from the traditional Chinese medicinal compound Sangguayin, which "clears heat and promotes fluid" and "tonifies kidney and spleen" for "Xiaoke", commonly known as 'Diabetes mellitus' in clinics. Previous studies have shown that SGY-P could reduce insulin resistance and repair damaged pancreas in db/db mice, but the underlying mechanisms were unclear. Here, we investigated whether treatment with SGY-P could protect pancreatic β-cells from apoptosis and uncovered the underlying mechanisms. db/db mice were used to observe the hypoglycemic and islet protective effect in vivo. Apoptosis was induced in mouse insulinoma 6 (MIN6) cells by palmitate, following which the cells were treated with SGY-P for elucidating the anti-apoptotic mechanism in vitro. Cell viability and nuclear morphology were detected by CCK-8 assay and Hoechst 33258 staining. The expression levels of apoptosis-, endoplasmic reticulum (ER) stress-, and autophagy-related proteins were measured by western blot. The results showed that SGY-P reduced fasting blood glucose, pancreatic pathological changes, and islet β-cell apoptosis in db/db mice. Palmitate-induced apoptosis in MIN6 cells was decreased by SGY-P treatment. Hence, SGY-P therapy exhibited a protective effect on pancreatic β-cells by decreasing the expression of cleaved caspase-3, cleaved PARP and Bax, and increasing Bcl-2 by suppressing ER stress (Bip/XBP1/IRE1α/CHOP/Caspase-12) and autophagy (LC3/p62/Atg5) pathways.2/Atg5) pathways.

Gymnema montanum improves endothelial function via inhibition of endoplasmic reticulum stress by activating Nrf2 signaling

Objective: To investigate the effects of Gymnema montanum leaf extract against endoplasmic reticulum (ER) stress-induced toxicity in endothelial cells. Methods: The immortalized endothelial hybrid cell, EA.hy926 was treated with different concentrations of Gymnema montanum leaf extract (0-100 μg/mL) and the ER stress inducer, tunicamycin. The cytotoxicity was assessed by MTT as well as lactate dehydrogenase and malondialdehyde levels were determined. The levels of ER stress markers, GRP78 and CHOP were analysed by Western blot assay. The Gymnema montanum leaf extract-mediated activation of nuclear factor erythroid 2-related factor 2 (Nrf2) was assessed by cell-based luciferase enzyme fragment complementation assay and antioxidant responsive element driven luciferase reporter assay. The levels of phosphoproteins of the MAPK pathway were analyzed using the Bioplex system. Results: A dose-dependent cytoprotective effect of Gymnema montanum leaf extract was observed in tunicamycin-induced toxicity. Gymnema montanum leaf extract significantly reduced lactate dehydrogenase activity and malondialdehyde levels in ER stress-induced endothelial cells. It also suppressed ER stress markers dose dependently and inhibited the phosphorylation of JNK, ERK, MEK and p38 MAPK in tunicamycin-induced endothelial cells. Moreover, Gymnema montanum leaf extract increased the expression of Nrf2 and its downstream targets in endothelial cells. Conclusions: Gymnema montanum leaf extract attenuates ER stress by increasing the expression of Nrf2 and its downstream genes.

Gymnema montanum improves endothelial function via inhibition of endoplasmic reticulum stress by activating Nrf2 signaling

Objective: To investigate the effects of Gymnema montanum leaf extract against endoplasmic reticulum (ER) stress-induced toxicity in endothelial cells.Methods: The immortalized endothelial hybrid cell, EA.hy926 was treated with different concentrations of Gymnema montanum leaf extract (0-100 μg/mL) and the ER stress inducer, tunicamycin. The cytotoxicity was assessed by MTT as well as lactate dehydrogenase and malondialdehyde levels were determined. The levels of ER stress markers, GRP78 and CHOP were analysed by Western blot assay. The Gymnema montanum leaf extract-mediated activation of nuclear factor erythroid 2-related factor 2 (Nrf2) was assessed by cell-based luciferase enzyme fragment complementation assay and antioxidant responsive element driven luciferase reporter assay. The levels of phosphoproteins of the MAPK pathway were analyzed using the Bioplex system. Results: A dose-dependent cytoprotective effect of Gymnema montanum leaf extract was observed in tunicamycin-induced toxicity. Gymnema montanum leaf extract significantly reduced lactate dehydrogenase activity and malondialdehyde levels in ER stress-induced endothelial cells. It also suppressed ER stress markers dose dependently and inhibited the phosphorylation of JNK, ERK, MEK and p38 MAPK in tunicamycin-induced endothelial cells. Moreover, Gymnema montanum leaf extract increased the expression of Nrf2 and its downstream targets in endothelial cells. Conclusions: Gymnema montanum leaf extract attenuates ER stress by increasing the expression of Nrf2 and its downstream genes.

The Chinese patent medicine, Jin-tang-ning, ameliorates hyperglycemia through improving β cell function in pre-diabetic KKAy mice / 中国天然药物

Jin-tang-ning (JTN), a Chinese patent medicine, mainly comprised of Bombyx moriL., has been proved to show α-glucosidase inhibitory efficacy and clinically effective for the treatment of type 2 diabetes (T2DM). Recently, we have reported that JTN could ameliorate postprandial hyperglycemia and improved β cell function in monosodium glutamate (MSG)-induced obese mice, suggesting that JTN might play a potential role in preventing the conversion of impaired glucose tolerance (IGT) to T2DM. In this study, we evaluated the effect of JTN on the progression of T2DM in the pre-diabetic KKAy mice. During the 10 weeks of treatment, blood biochemical analysis and oral glucose tolerance tests were performed to evaluate glucose and lipid profiles. The β cell function was quantified using hyperglycemic clamp at the end of the study. JTN-treated groups exhibited slowly raised fasting and postprandial blood glucose levels, and also ameliorated lipid profile. JTN improved glucose intolerance after 8 weeks of treatment. Meanwhile, JTN restored glucose-stimulated first-phase of insulin secretion and induced higher maximum insulin levels in the hyperglycemic clamp. Thus, to investigate the underlying mechanisms of JTN in protecting β cell function, the morphologic changes of the pancreatic islets were observed by optical microscope and immunofluorescence of hormones (insulin and glucagon). Pancreatic protein expression levels of key factors involving in insulin secretion-related pathway and ER stress were also detected by Western blot. Pre-diabetic KKAy mice exhibited a compensatory augment in β cell mass and abnormal α cell distribution. Long-term treatment of JTN recovered islet morphology accompanied by reducing α cell area in KKAy mice. JTN upregulated expression levels of glucokinase (GCK), pyruvate carboxylase (PCB) and pancreas duodenum homeobox-1 (PDX-1), while down-regulating C/EBP homologous protein (Chop) expression in pancreas of the hyperglycemic clamp, which indicated the improvement of mitochondrial metabolism and relief of endoplasmic reticulum (ER) stress of β cells after JTN treatment. These results will provide a new insight into exploring a novel strategy of JTN for protecting β cell function and preventing the onset of pre-diabetes to T2DM.

Anti-inflammatory effect of Lycium barbarum on polarized human intestinal epithelial cells

BACKGROUND/OBJECTIVES: Inflammatory Bowel Disease (IBD) has rapidly escalated in Asia (including Korea) due to increasing westernized diet patterns subsequent to industrialization. Factors associated with endoplasmic reticulum (ER) stress are demonstrated to be one of the major causes of IBD. This study was conducted to investigate the effect of Lycium barbarum (L. barbarum) on ER stress. MATERIALS/METHODS: Mouse embryonic fibroblast (MEF) cell line and polarized Caco-2 human intestinal epithelial cells were treated with crude extract of the L. chinense fruit (LF). Paracellular permeability was measured to examine the effect of tight junction (TJ) integrity. The regulatory pathways of ER stress were evaluated in MEF knockout (KO) cell lines by qPCR for interleukin (IL) 6, IL8 and XBP1 spliced form (XBP1s). Immunoglobulin binding protein (BiP), XBP1s and CCAAT/enhancer-binding homologous protein (CHOP) expressions were measured by RT-PCR. Scanning Ion Conductance Microscopy (SICM) at high resolution was applied to observe morphological changes after treatments. RESULTS: Exposure to LF extract strengthened the TJ, both in the presence and absence of inflammation. In polarized Caco-2 pretreated with LF, induction in the expression of proinflammatory marker IL8 was not significant, whereas ER stress marker XBP1s expression was significantly increased. In wild type (wt) MEF cells, IL6, CHOP and XBP1 spliced form were dose-dependently induced when exposed to 12.5–50 µg/mL extract. However, absence of XBP1 or IRE1α in MEF cells abolished this effect. CONCLUSION: Results of this study show that LF treatment enhances the barrier function and reduces inflammation and ER stress in an IRE1α-XBP1-dependent manner. These results suggest the preventive effect of LF on healthy intestine, and the possibility of reducing the degree of inflammatory symptoms in IBD patients.

Poly-PR in C9ORF72-Related Amyotrophic Lateral Sclerosis/Frontotemporal Dementia Causes Neurotoxicity by Clathrin-Dependent Endocytosis / 神经科学通报·英文版

GGGGCC repeat expansions in the C9ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). It has been reported that hexanucleotide repeat expansions in C9ORF72 produce five dipeptide repeat (DPR) proteins by an unconventional repeat-associated non-ATG (RAN) translation. Within the five DPR proteins, poly-PR and poly-GR that contain arginine are more toxic than the other DPRs (poly-GA, poly-GP, and poly-PA). Here, we demonstrated that poly-PR peptides transferred into cells by endocytosis in a clathrin-dependent manner, leading to endoplasmic reticulum stress and cell death. In SH-SY5Y cells and primary cortical neurons, poly-PR activated JUN amino-terminal kinase (JNK) and increased the levels of p53 and Bax. The uptake of poly-PR peptides by cells was significantly inhibited by knockdown of clathrin or by chlorpromazine, an inhibitor that blocks clathrin-mediated endocytosis. Inhibition of clathrin-dependent endocytosis by chlorpromazine significantly blocked the transfer of poly-PR peptides into cells, and attenuated poly-PR-induced JNK activation and cell death. Our data revealed that the uptake of poly-PR undergoes clathrin-dependent endocytosis and blockade of this process prevents the toxic effects of synthetic poly-PR peptides.

Effects of ER Stress and PUMA on 5-FU-induced Liver Cell Injury and Apoptosis / 中山大学学报(医学科学版)

@#【Objective】To investigate the role of ER stress and PUMA in 5-FU-induced liver cells injury and apoptosis.【Methods】We established 5-FU-induced liver injury models by intraperitoneally injecting the isodose 5-FU to 10 PUMA knockout mice(PUMA-KO)and 20 PUMA Wild type mice(PUMA-WT). Meanwhile,10 WT mice were intraperitoneally injected with 4-Phenylbutyric acid,the ER stress inhibitor. In the control group,10 KO mice and 20 WT mice were given the same amount of normal saline.After the modeling,serum and liver tissues of the mice were collected to assess the degree of liver pathological injury,measure the expression levels of ALT and AST in serum,and detect the expression levels of PUMA and GRP78 in liver tissues. The changes of these indicators in different treatment groups were observed and compared.【Results】Compared with the WT control group,serum ALT and AST levels were significantly increased in the 5-FU group,H&E staining showed punctate focal necrosis,accompanied by hemorrhage and inflammation. TUNEL staining showed apoptotic cells were markedly added(Z = 3.78,P < 0.001),and expressions of PUMA and GRP78 were obviously augmented,suggesting that both PUMA and ER stress were involved in 5-FU-induced liver cells injury and apoptosis. Then,in the 4-PBA group,we found that the expression levels of GRP78 and PUMA were down-regulated,and apoptosis of liver cells was reduced under the same dose of 5-FU(χ~2= 32.99,Z = 3.78,P <0.001),further confirming that both PUMA and ER stress were involved in this process. Subsequently,it was found that,when induced by the same dose of 5-FU,cleaved caspase-3 staining showed that the liver apoptosis signal of the PUMA knockout mice was lower than the WT mice(χ~2= 33.99,Z = 3.78,P < 0.001),but the difference in the expression of GRP78 between the two groups was not statistically significant. In summary,the expression of PUMA was reduced and the apoptosis of liver cells was attenuated after the inhibition of ER stress;PUMA knockdown could not influence the activation of ER stress but alleviated apoptosis of liver cells.【Conclusions】PUMA mediates ER stress-up-regulated liver cells apoptosis in 5-FU-induced Chemotherapeutic liver injury.

Effect of particulate matter 2.5 at urban centre of Hangzhou on lung impairment in rats / 中国应用生理学杂志

OBJECTIVE@#To explore the effect of ambient particle matter 2.5 (PM2.5) collected in the urban center of Hangzhou on the lung injury of rats and on the activating of endoplasmic reticulum pathway.@*METHODS@#PM2.5 samples were collected on quartz fiber filters using a PM2.5 high-volume air sampler in the urban area of Hangzhou. The collected PM2.5 particles were extracted in ultrapure water and concentrated by vacuum freeze-drying. Twenty-four male Sprague-Dawly (SD) rats were randomly divided into 3 groups:saline control group, low dose PM2.5 exposure group (5 mg/kg BW) and high dose PM2.5 exposure groups (25 mg/kg BW). Each group received intratracheal instillation of PM2.5, once a week for 4 weeks. Twenty-four hours after the last exposure, the rats were narcotized and sacrificed, left lung was isolated and fixed with 4% paraformaldehyde for histopathological detection. The bronchoalveolar lavage fluid (BALF) was collected from the right lung. The total antioxidant capacity (T-AOC) level, the activities of superoxide dismutase (SOD) and lactic dehydrogenase (LDH) in BALF were detected by chemical colorimetry. The level of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) cytokines in BALF was measured by enzyme linked immunosorbent assay (ELISA). And the protein expressions of glucose-regulated protein 78 (GRP78), phosphorylated protein kinase receptor-like endoplasmic reticulum kinase (p-PERK), phosphorylated eukaryotic translation initiation factor (p-eIF2α), transcription factors C/EBP homologue protein (CHOP), inositol-requiring enzyme 1α (IRE1α) and X-box binding protein 1 (XBP1) in lung tissue were determined by Western blotting.@*RESULTS@#Compared with control group, rats in both low dose (5 mg/kg) and high dose (25 mg/kg) PM2.5-treated groups showed obviously dose-dependent pulmonary toxicity including thickening of alveolar walls, narrowing of alveolar space, interstitial hyperplasia and inflammatory cell infiltration. Compared with control group, T-AOC level and the SOD activity in BALF in both PM2.5-treated groups were decreased dose-dependently (<0.05), whereas the LDH activity in BALF were increased in a dose-dependent manner (<0.05). Exposure to PM2.5 resulted in a increasing of the release of proinflammatory cytokines including TNF-α, IL-1β and IL-6 in rat lung in a dose-dependent manner (<0.05). The levels of GRP78, p-PERK, p-eIF2α, CHOP, IRE1α and spliced XBP1 (XBP1-S) were significantly up-regulated, whereas the level of unspliced XBP1 (XBP1-U) was down-regulated in the rat lung tissue of high-dose PM2.5 treated group.@*CONCLUSIONS@#The PM2.5 in the urban area of Hangzhou can significantly cause lung inflammatory injury in rats. Both oxidative stress and activation of ER stress pathways may be related to such PM2.5 inhalation-induced lung inflammatory injury.