Project description:Myeloperoxidase (MPO), oxidative stress (OS), and endoplasmic reticulum (ER) stress are all increased in the lungs of neonatal rat pups raised in hyperoxia (HOX, >90% O2), an established model of bronchopulmonary dysplasia (BPD). However, the relationship between OS, MPO, and ER stress has not been examined in HOX rat pups. To determine the relationship between OS, MPO, and ER stress in BPD we treated Sprague-Dawley neonatal rat pups with Tunicamycin (Tun) or with HOX. Tun directly induces ER stress and simplifies neonatal lung alveolarization. Previously, we showed that HOX induces a cycle of destruction that we hypothesize through increased OS, MPO, and ER stress to induce BPD. To inhibit ER stress specifically, we used tauroursodeoxycholic acid (TUDCA), a molecular chaperone. To break the cycle of destruction and reduce OS and MPO we used N-acetyl-lysyltyrosylcysteine-amide (KYC), a systems pharmacology agent. Lung structure was studied morphometrically. ER stress was detected using immunofluorescence (IF), transcriptomic, proteomic, and electron microscopic analyses. Increased ER stress was observed in the lungs of HOX rat pups and also in human BPD lungs by IF. Morphometric and proteomic studies of rat lungs showed that Tun treatment decreased lung complexity and increased ER stress and BPD severity. The fact that TUDCA improved lung complexity in Tun-treated neonatal rat pups, and decreased BPD induced by HOX provides strong support for the idea that ER stress plays a causal role in BPD. Additional support comes from data showing TUDCA decreased lung myeloid cells and MPO levels in the lungs of both Tun- and HOX-treated neonatal rat pups. These data link OS and MPO to ER stress in the mechanisms mediating BPD. KYC's effective inhibition of ER stress in the lungs of Tun-treated rat pups provides additional support for the idea that MPO-induced ER stress plays a direct causal role in BPD. Thus, ER stress appears to expand our proposed cycle of destruction. Our results suggest ER stress evolves from OS and MPO to increase neonatal lung injury and impaired neonatal lung growth and development. The encouraging effect of TUDCA indicates chemical chaperone has the potential in treating BPD. Using multiomic data to investigate the role of endoplasmic reticulum stress in the development of BPD in rat model.
Project description:Oxidative stress (OS), inflammation, and endoplasmic reticulum (ER) stress sequentially occur in the rat model of hyperoxia (HOX) induced bronchopulmonary dysplasia (BPD), and they all increase DNA damage. Tumor suppressors increase after DNA damage, followed by apoptosis or cellular senescence when the damage becomes irreparable. Although cellular senescence contributes to wound healing, its persistence will inhibit growth potential. Therefore, we hypothesized that the persistence of cellular senescence plays a role in BPD progression. We detected evidence of increased cellular senescence in rat and human BPD lungs. Foxo4-p53 binding was increased in BPD rat lungs, and inhibition of this binding attenuated BPD severity, indicating that such binding contributes to BPD's cellular senescence. Treatment with tauroursodeoxycholic acid (TUDCA) decreases ER stress. N-Acetyl-lysyltyrosylcysteine-amide (KYC) reduced toxic oxidant production by myeloperoxidase (MPO) and subsequent OS and inflammation. Both agents effectively decreased cellular senescence. Concomitantly, alveolar complexity and the number of type 2 alveolar cells increased, indicating that MPO-mediated OS and ER stress preceded cellular senescence in BPD rat pup lungs. These data suggest that cellular senescence plays an essential role in BPD progression. Reducing MPO toxic oxidant production, ER stress, and attenuating cellular senescence are potential therapeutic strategies for halting BPD progression. Using multiomic data to investigate the role of cellular senescence in the development of BPD in rat model.
Project description:We synthesized novel fluorescent thalidomide analogs (2,6-dialkylphenyl-4/5-amino-substituted-5,6,7-trifluorophthalimides) that localize specifically to lipid droplets. By using affinity chromatography interacting proteins were identified: Rab7, Rab10, Rab11, Sec22b, sorting nexin 2, calnexin, protein disulfide isomerase, GRP78, GRP94 among others that are involved in vesicular transport and ER stress response. Amino-trifluoro-phthalimides exerted potent anticancer activities in vitro on different cell lines including melanoma, leukemia, hepatocellular carcinoma, glioblastoma. They are non-toxic to adult animals up-to 1 g/kg but are highly teratogenic to zebrafish embryos at micromolar concentrations resulting defects in developing muscle. The analogs resulted in calcium release from the endoplasmic reticulum (ER), induction of reactive oxygen species (ROS), ER stress and finally apoptosis. Gene expression analysis confirmed the induction of ER stress-mediated apoptosis pathway components, such as growth arrest- and DNA damage-inducible gene 153 (GADD153), ATF3, Luman/CREB3 recruitment factor (LRF) and the ER-associated degradation-related gene HERPUD1. Tumor suppressors, P53, LATS2 and ING3 were also up-regulated in various cell lines after drug treatment. Exogenous docosahexaenoic acid or eicosapentaenoic acid induced calcium release and ROS and synergized with the analogs in vitro, while oleic acid had no such an effect. Different antioxidants partially, intracellular calcium chelator almost completely diminished ROS production. Amino-phthalimides down-regulated the expression of CCL2, which is implicated in tumor metastasis and angiogenesis. Because of the anticancer, anti-angiogenic action and the wide range of applicability of the immunomodulatory drugs, lipid droplet-binding members of this family could represent a new class of agents by affecting ER-membrane integrity and perturbations of ER homeostasis. 4 replica, 2 dye-swap
Project description:Background: Pachymic acid (PA) is a purified triterpene extracted from medicinal fungus Poria cocos. In this paper, we investigated the anticancer effects of PA on human chemotherapy resistant pancreatic cancer cells. Methods: Gemcitabine-resistant pancreatic cancer cells PANC-1 and MIA PaCa-2 were used, along with a xenograft model of MIA PaCa-2 cells implanted in mice. Apoptosis was assessed by quantitation of cytoplasmic histone-associated DNA fragments and expression of cleaved PARP. Differential expression of genes was identified using comparative DNA microarray analysis. Protein levels were determined by immunoblotting. Toxicology studies in vivo were assessed by detecting pathological changes in organs and liver enzyme profiles in plasma. Tumor tissues were analyzed by quantification of apoptotic bodies, qRT-PCR and immunoblotting. Principal Findings: PA induced endoplasmic reticulum (ER) stress in chemotherapy resistant pancreatic cancer cells through activation of heat shock response and unfolded protein response related genes, which further triggered apoptosis. The involvement of ER stress was confirmed by increasing expression of XBP-1s, ATF4, Hsp70, CHOP and phospho-eIF2M-NM-1. Moreover, 25 mg kgM-bM-^HM-^R1 of PA significantly suppressed MIA PaCa-2 tumor growth in vivo without toxicity, which correlated with induction of apoptosis, ER stress related genes and proteins expression. Conclusions: Growth inhibition and induction of apoptosis by PA in chemotherapy resistant pancreatic cancer cells were associated with ER stress activation both in vitro and in vivo. Pancreatic cancer cell line treated with pachymic acid vs. control (untreated)
Project description:To investigate whether ER stress underpins the secretion of mis-glycosylated glycoproteins by trophoblast, we treated trophoblast-like BeWo cells with the ER stress inducer thapsigargin (Tg), an inhibitor specific for sarco/endoplasmic reticulum Ca2+-ATPase.
Project description:Effects of calcitriol on expressions of ER stress related genes were evaluated with microarray. Calcitriol, the active form of vitamin D, is known to induce apoptosis in cancer cells and increase intracellular calcium. Increase in cytopalsmic calcicium levels may indicate a decrease in endoplasmic reticulum (ER) calcium levels since ER is the main storage unit for calcium. Decrease in ER calcium levels are known to induce ER stress which can lead to apoptosis. However the effects of calcitriol on ER stress have not been reported before. Here we hypotesized that the cellular effects of calcitriol can be explained by induction of ER stress. We have tested this hypothesis by assessing calcitriol induced transcriptomic alterations with a focus on ER stress related genes.
Project description:AtbZIP60 is one of the transcription factors involved in the endoplasmic reticulum (ER) stress response in Arabidopsis. To identify genes under the control of AtbZIP60 during ER stress, we compared the genome-wide expression profiles of wild-type and atbzip60 mutant plants in response to the ER stress inducer tunicamycin.
Project description:COL4A3/A4/A5 mutations have been identified as critical causes of Alport syndrome and other genetic chronic kidney diseases. However, the underlying pathogenesis remains unclear, and specific treatments are lacking. Here, we constructed a transgenic Alport syndrome mouse model by generating a mutation (Col4a3 p.G799R) identified previously from one large Alport syndrome family into mice. We observed that the mutation caused a pathological decrease in intracellular and secreted collagen IV α3α4α5 heterotrimers. The mutant collagen IV α3 chains abnormally accumulated in the endoplasmic reticulum and exhibited defective secretion, leading to persistent endoplasmic reticulum stress in vivo and in vitro. RNA-seq analysis revealed that the MyD88/p38 MAPK pathway plays key roles in mediating subsequent inflammation and apoptosis signaling activation. Treatment with tauroursodeoxycholic acid, a chemical chaperone drug that functions as an endoplasmic reticulum stress inhibitor, effectively suppressed endoplasmic reticulum stress, promoted secretion of the α3 chains, and inhibited the activation of the MyD88/p38 MAPK pathway. Tauroursodeoxycholic acid treatment significantly improved renal function in vivo. These results partly clarified the pathogenesis of renal injuries associated with Alport syndrome, especially in glomeruli, and suggested that tauroursodeoxycholic acid might be useful for the early clinical treatment of Alport syndrome.
Project description:Bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, has been linked to endoplasmic reticulum (ER) stress. To investigate a causal role for ER stress in BPD pathogenesis, we generated mice (cGrp78f/f) with lung epithelial cell-specific knockout (KO) of Grp78, a gene encoding the ER chaperone 78-kDa glucose-regulated protein (GRP78), a master regulator of ER homeostasis and the unfolded protein response (UPR). Lung epithelial-specific Grp78 KO disrupted lung morphogenesis, causing developmental arrest, increased alveolar epithelial type II cell apoptosis and decreased surfactant protein and type I cell marker expression in perinatal lungs. cGrp78f/f pups died immediately after birth, likely due to respiratory distress. Importantly, Grp78 KO triggered UPR activation with marked induction of pro-apoptotic transcription factor C/EBP homologous protein (CHOP). Increased expression of genes involved in oxidative stress and cell death and decreased expression of genes encoding antioxidant enzymes suggest a role for oxidative stress in alveolar epithelial cell (AEC) apoptosis. Increased Smad3 phosphorylation and expression of transforming growth factor-β (TGF-β)/Smad3 targets Cdkn1a (encoding p21) and Gadd45a suggest that interactions among the apoptotic arm of the UPR, oxidative stress and TGF-β/Smad signaling pathways contribute to Grp78 KO-induced AEC apoptosis and developmental arrest. Chemical chaperone taursodeoxycholic acid reduced UPR activation and apoptosis in cGrp78f/f lungs cultured ex vivo, confirming a role for ER stress in observed AEC abnormalities. These results demonstrate a key role for GRP78 in AEC survival and gene expression during lung development through modulation of ER stress and suggest the UPR as a potential therapeutic target in BPD. Whole-genome expression profiling was performed using MouseRef-8 v2.0 Expression BeadChips (Illumina) on RNA isolated from lungs of four Grp78f/f and three cGrp78f/f mice at E18.
Project description:The endoplasmic reticulum (ER) is the site of secretory lipoprotein production and de novo cholesterol synthesis, yet little is known about how these activities are coordinated with each other, or with the activity of the COPII machinery, which transports ER cargo to the Golgi. The Sar1B component of this machinery is mutated in Chylomicron Retention Disorder, establishing that this Sar1 isoform secures delivery of dietary lipids into the circulation. We used microarrays to investigate the effect of overexpression of Sar1 isoforms and a constitutively active mutant form of Sar1B, Sar1B:H79G, on global gene expression in rat hepatoma cell line, McArdle RH7777 and identified a strong down-regulation of cholesterol biosynthetic gene mRNA expression in the Sar1B:H79G-, but not the wild-type Sar1A- or Sar1B-overexpressing cell lines. RNA was extracted from cell cultures of control McArdle RH7777, and transgenic lines overexpressing human Sar1-isoforms: one for Sar1A, two for Sar1B and two expressing a constitutively active mutant form of Sar1B, Sar1B:H79G, that cannot complete GTP hydrolysis, and hybridized on Affymetrix GeneChip Rat Genome 230 2.0 arrays.