Next Generation Sequencing Facilitates Quantitative Analysis of Wild Type animal fed normal and high glucose diets at different age
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ABSTRACT: Metabolic diseases are strongly associated with endoplasmic reticulum (ER) stress. Upon ER stress, the unfolded protein response (UPR) is activated to limit cellular damage. However, escalating cellular UPR response weakens with age. Here, we show that 5-day-old Caenorhabditis elegans fed a bacteria diet with 2% glucose (high glucose diet, HGD-5) extend their lifespan while shortening the lifespan of 1-day-old (HGD-1) animals. We observed a metabolic shift in HGD-1 as glucose and fertility synergistically prolonged the lifespan of HGD-5, independently of DAF-16. Notably, we identified that UPR stress sensors ATF-6 and PEK-1 extended the longevity of HGD-5 worms, while the ire-1 ablation drastically increased HGD-1 lifespan. Based on these observations, we postulate that HGD activates the otherwise quiescent UPR in aged worms to overcome ageing-related stress and restore ER homeostasis. In contrast, young animals subjected to HGD provokes unresolved ER stress, conversely leading to a detrimental stress response.
Project description:All animals must maintain genome and proteome integrity, especially when experiencing endogenous or exogenous stress. To cope, organisms have evolved sophisticated and conserved response systems: unfolded protein responses (UPRs) ensure proteostasis while the DNA damage response (DDR) maintains genome integrity. Emerging evidence suggests that UPRs and DDRs crosstalk, but the extent of crosstalk remains poorly understood. Here, we demonstrate that inactivation of the DNA primases pri-1 and pri-2, which synthesize RNA primers at replication forks and whose inactivation causes DNA damage, activates the UPR of the endoplasmic reticulum (UPR-ER) in Caenorhabditis elegans, with especially strong activation in the germline. We observed activation of both the inositol-requiring-enzyme 1 (ire-1) and the protein kinase RNA-like ER kinase (PEK-1) branches of the UPR-ER. Interestingly, activation of the UPR-ER output gene hsp-4/BiP was partially independent of its canonical activators, ire-1 and xbp-1, and instead required the third branch of the UPR-ER, atf-6, suggesting functional redundancy. We further found that primase depletion specifically induces the UPR-ER, but not the mechanistically distinct cytosolic or mitochondrial UPRs, suggesting that primase inactivation causes compartment-specific rather than global stress. Functionally, loss of ire-1 or pek-1 sensitized animals to replication stress caused by hydroxyurea. Finally, transcriptome analysis of pri-1 embryos revealed several deregulated processes that could cause UPR-ER activation, including protein glycosylation, calcium signaling, and fatty acid desaturation. Together, our data show that the UPR-ER, but not other UPRs, responds to replication fork stress and that the UPR-ER is required to alleviate this stress.
Project description:The endoplasmic reticulum (ER) is an organelle associated with lipid metabolism. However, the involvement of the ER in nutritional status-dependent energy homeostasis is largely unknown. The results of this study demonstrate that IRE-1, an ER protein known to be involved in the unfolded protein response, and HSP-4, an ER chaperone, regulate expression of the novel fasting-induced lipases FIL-1 and FIL-2, which induce fat granule hydrolysis upon fasting in C. elegans. RNAi and ectopic expression experiments demostrated that FIL-1 and FIL-2 are both necessary and sufficient for fasting-induced fat granule breakdown. Failure of ire-1 and hsp-4 mutant animals to hydrolyze fat granules during starvation impaired their motility, which was rescued by glucose supplementation of their media, implicating the importance of ire-1/hsp-4-dependent lipolysis for energy supply from stored fat during fasting. Taken together, these data suggest that the ER-resident proteins IRE-1 and HSP-4 are key nutritional sensors that modulate expression of inducible lipases to maintain whole-body energy homeostasis in C. elegans. Synchronized L4 worms were divided into well-fed and 6 hours fasted samples for RNA extraction and hybridization on an Agilent microarray.
Project description:The unfolded protein response (UPR) is a cellular defense mechanism against glucose deprivation, a cell condition that occurs in solid tumors. A key feature of the UPR is the activation of the transcription program that allows the cell to cope with endoplasmic reticulum (ER) stress. We used micoarrays to show that the UPR transcription program is disrupted by the antitumor macrocyclic compound versipelostatin (VST) and antidiabetic biguanides metformin, buformin and phenformin, depending on cellular glucose availability. Experiment Overall Design: Total 42 samples were prepared for RNA extraction and hybridization on Affymetrix microarrays. Experiment Overall Design: To induce the UPR, we treated cells (HeLa, HT-29, HT1080, MKN74) for 15 or 18 hours under ER stress conditions by replacing the medium with glucose-free medium or by adding either 2-Deoxy-D-glucose (2DG) or Tunicamycin (TM) to glucose-containing medium. UPR modulators (VST, biguanides or pyrvinium pamoate) were added at various final concentrations immediately after cells were placed in glucose-free medium or just before the chemical stressors were added to glucose-containing culture medium.
Project description:The endoplasmic reticulum (ER) is an organelle associated with lipid metabolism. However, the involvement of the ER in nutritional status-dependent energy homeostasis is largely unknown. The results of this study demonstrate that IRE-1, an ER protein known to be involved in the unfolded protein response, and HSP-4, an ER chaperone, regulate expression of the novel fasting-induced lipases FIL-1 and FIL-2, which induce fat granule hydrolysis upon fasting in C. elegans. RNAi and ectopic expression experiments demostrated that FIL-1 and FIL-2 are both necessary and sufficient for fasting-induced fat granule breakdown. Failure of ire-1 and hsp-4 mutant animals to hydrolyze fat granules during starvation impaired their motility, which was rescued by glucose supplementation of their media, implicating the importance of ire-1/hsp-4-dependent lipolysis for energy supply from stored fat during fasting. Taken together, these data suggest that the ER-resident proteins IRE-1 and HSP-4 are key nutritional sensors that modulate expression of inducible lipases to maintain whole-body energy homeostasis in C. elegans.
Project description:A high-sugar diet induces lifestyle-associated metabolic diseases, such as obesity and diabetes, which may underlie the pro-tumor effects of a high-sugar diet. We supplied GL261 syngeneic glioblastoma (GBM) model mice with a short-term high-glucose diet (HGD) and found an increased survival rate with no evidence of metabolic disease. Modulation of the gut microbiota by an HGD was critical for enhancing the anti-tumor immune response. Single-cell RNA sequencing showed that modulation of the gut microbiota by an HGD increased the T cell-mediated anti-tumor immune response in GBM mice. We found that the cytotoxic CD4+ T cell population in GBM mice increased due to synergy with anti-PD-1 immune checkpoint inhibitors, but this depended on an HGD. Thus, we determined that an HGD enhanced anti-tumor immune responses in GBM mice through changes in the gut microbiota and suggest that the role of an HGD in GBM should be re-examined.
Project description:Inhibiting the unfolded protein response (UPR) can be a therapeutic approach, especially for targeting the tumor microenvironment. We found that compound C (also known as dorsomorphin) prevented the UPR and exerted enhanced cytotoxicity during glucose deprivation. The UPR-inhibiting activity of compound C was not associated with either AMPK or BMP signaling inhibition. To induce the UPR, we treated HT1080 cells for 18 hours under ER stress conditions by adding 10 mM 2-Deoxy-D-glucose (2DG) to culture medium. UPR inhibitors (compound C, versipelostatin and phenformin) were added just before 2DG was added in medium. Total 8 samples were prepared for RNA extraction and hybridization on Affymetrix microarrays.
Project description:The unfolded protein response (UPR) is a cellular defense mechanism against glucose deprivation, a cell condition that occurs in solid tumors. A key feature of the UPR is the activation of the transcription program that allows the cell to cope with endoplasmic reticulum (ER) stress. We used micoarrays to show that the UPR transcription program is disrupted by the antitumor macrocyclic compound versipelostatin (VST) and antidiabetic biguanides metformin, buformin and phenformin, depending on cellular glucose availability. Keywords: stress response, drug response
Project description:Cancer cells consume large amounts of glucose because of their specific metabolic pathway. However, cancer cells exist in tumor tissue where glucose is insufficient. To survive, cancer cells likely have the mechanism to elude their glucose addiction. Here we show that functional mitochondria are essential if cancer cells are to avoid glucose addiction. Cancer cells with dysfunctional mitochondria, such as mitochondrial DNA-deficient rho0 cells and electron transport chain blocker-treated cells, were highly sensitive to glucose deprivation. Our data demonstrated that this sensitization was caused by failure of the unfolded protein response (UPR), an adaptive response mediated by the endoplasmic reticulum (ER). This study suggests a link between mitochondria and the ER during the UPR under glucose deprivation conditions and that mitochondria govern cell fate, not only through ATP production and apoptosis regulation but also through modulating the UPR for cell survival. Human cancer cell lines (HT-1080, HT-29, and mtDNA-deficient cells derived from these cell lines) were selected for RNA extraction and hybridization on Affymetrix microarrays. We examined the unfolded protein response (UPR), an adaptive response mediated by the endoplasmic reticulum (ER), of cancer cells under stress conditions. Abbreviations List: AA, antimycin A; Bu, buformin; Met, metformin; Phen, phenformin; Rot, rotenone; VST, versipelostatin; TM, tunicamycin; 2DG, 2-deoxyglucose; GS, glucose starvation. Capital S (_S) indicates the supernatant of sample including floating cells.
Project description:Cold affects many aspects of biology, medicine, agriculture and industry. Here, we identify a conserved endoplasmic reticulum (ER) stress response, distinct from the canonical unfolded protein response, which maintains lipid homeostasis during extreme cold stress. We establish that the ER stress sensor IRE-1 is critical for resistance to extreme cold and is activated by cold temperature. Specifically, neuronal IRE-1 signals via JNK-1 and neuropeptide-mediated signalling to regulate lipid composition throughout the animal. The requirement of this cold-response pathway can be bypassed by supplementation with unsaturated fatty acids or by altering the diet . Altogether, our findings define an ER-centric conserved organism-wide cold stress response pathway, consisting of sensors, effectors and signalling moieties, which control adaptation to cold throughout the organism. Better understanding of the molecular basis of cold adaptation is crucial for the design of safe and optimal use of cold conditions on live organisms and samples, and for the development of better treatments for hypothermia. Conclusions: Our study represents a detailed analysis of C.elegans transcriptomes during cold stress, with biological replicates, generated by RNA-seq technology.
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.