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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.
2016-01-15 | E-GEOD-70208 | biostudies-arrayexpress
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.
2016-01-15 | GSE70208 | GEO
Project description:Analysis of Grp78 deficiency in lung epithelial type 2 cells.
| PRJNA495820 | ENA
Project description:Covid-19 syndrome is characterized by an acute lung injury phenotype marked by hypoxemic respiratory failure and high mortality. Alveolar Type 2 (AT2) cells are essential for gas exchange, repair, and regeneration of distal lung epithelium. We have shown that the causative agent, SARS-CoV-2 and other members of the b coronavirus genus induces an ER stress response in vitro however the consequences for host AT2 cell function in vivo are less understood. To study this, two murine models of coronavirus infection were employed– mouse hepatitis virus-1 (MHV-1) in A/J mice and a C57BL6/j adapted SARS-CoV-2 strain. MHV-1 infected mice exhibited dose-dependent weight loss through Day 8 (8dpi) with histological evidence of distal lung injury accompanied by elevated BALF cell counts and total protein. AT2 cells isolated at 4dpi and 8dpi showed evidence of both viral infection and increases in Bip /GRP78 expression, consistent with activation of the unfolded protein response (UPR). AT2 UPR signaling included elevations in spliced XBP-1 indicating activation of IRE1a signaling as well as a biphasic response in PERK signaling mark by phosphorylated eIF2a protein levels and expression of Atf4, Ppp1r15a, and Ddit3. Viral UPR activation was accompanied by marked reductions in AT2 and BALF surfactant protein (SP-B, SP-C) content, increases in surfactant surface tension, and emergence of a re-programmed epithelial cell population (Krt8+, Cldn4+, and Gdf15+) which was attenuated by treatment with the IRE1a inhibitor OPK711. As proof-of-concept, C57BL6 mice infected with mouse-adapted SARS-CoV-2 demonstrated similar lung injury and evidence of disrupted surfactant homeostasis. We conclude that hypoxic respiratory failure from b-coronavirus infection results from an aberrant AT2 cell host response activating multiple ER stress pathways, altering surfactant metabolism / function, and changing AT2 endophenotypes offering a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and hypoxemic respiratory failure.
2024-06-27 | GSE244820 | GEO
Project description:To investigate the role of nuclear GRP78 on transcriptional activity
2023-06-30 | GSE232661 | GEO
Project description:Nuclear GRP78 on transcription regulation
| PRJNA973114 | ENA
Project description:Constitutive knockdown of Cldn18 in mice showed lung enlargement and increased proliferation of alveolar epithelial type II (AT2) cells. Lung AT2 cells were isolated from wild-type and knockout mice and subjected to microarray analysis. Results provide insight into the role of Cldn18 in controlling organ size and stem progenitor cells.
2018-06-30 | GSE106233 | GEO
Project description:The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the UPR. Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest a component of UPR induction in arv1? strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, C/EBP homologous protein (CHOP) and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis resulting in a disruption of ER integrity, one consequence of which is induction of the UPR. Yeast strains were grown to mid-logarithmic stage (A600=0.5-0.6) for RNA extraction and hybridization on Ye6100 or S98 Affymetrix gene chips. The control array (sample name C) was carried out in duplicate. The ARV1 mutant array (sample name A) was carried out in triplicate. Both ARV1 mutants Ye6100 arrays were compared to the same control Ye6100 array. Strains represent different isolates of the same genotype, mating type and genetic background (w303). Sturley lab collection (SCY) strains include SCY328 and SCY2004 for controls and SCY820 and SCY840 for ARV1 mutants.
2011-02-17 | E-GEOD-26801 | biostudies-arrayexpress
Project description:Conjunctival melanoma (CM) is a rare and fatal malignant eye tumor, it is life-threatening, mainly because of the lack of diagnostic biomarkers or drug access. In this study, we deciphered a novel anti-CM mechanism of a natural tetracyclic compound isolated from a Cucurbitaceae family plant and named as Cucurbitacin B (CuB). We found that CuB remarkably inhibited the proliferation of CRMM2 cells at a submicromolar level (IC50=0.15 μM) without toxicity to normal cells via G2/M cell cycle arrest and subsequent cell apoptosis. RNA-seq screening identified the Kinesin family member 20A (KIF20A) as a key gene which was abolished by the CuB treatment and proved to be a downstream effector of FOXM1 pathway. Further target identification by the activity-based protein profiling (ABPP) chemoproteomic approach revealed that 78 KDa Glucose-Regulated Protein (GRP78) is a potential target of CuB. Several lines of evidence demonstrated that CuB interacted with GRP78 and bound with a Kd value of 0.11 μM. Furthermore, functional experiments showed that CuB suppressed the ATPase activity of GRP78 both in human recombinant GRP78 and cellular lysates. Knockdown of the GRP78 gene significantly induced the downregulation of FOXM1 and related pathway genes including KIF20A, underlying an interesting therapeutic perspective. Taken together, our current work proved a substantial therapeutic potential of the traditional medicine CuB, and it needs to be explored further for future CM therapies.
2022-05-31 | GSE192359 | GEO
Project description:The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the UPR. Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest a component of UPR induction in arv1? strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, C/EBP homologous protein (CHOP) and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis resulting in a disruption of ER integrity, one consequence of which is induction of the UPR.
2011-02-17 | GSE26801 | GEO