Activation of the Mitochondrial Stress Response in Clear Cell Renal Cell Carcinoma
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE134933 | GEO | 2020/08/01
REPOSITORIES: GEO
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Project description:The integrated stress response (ISR) is a key cellular signaling pathway activated by environmental alterations that represses protein synthesis to restore homeostasis. To prevent sustained damage, the ISR is counteracted by the upregulation of Growth Arrest and DNA Damage inducible 34 (GADD34), a stress-induced regulatory subunit of protein phosphatase 1 that mediates translation reactivation and stress recovery. Here, we uncover a novel ISR regulatory mechanism that post-transcriptionally controls the stability of PPP1R15A mRNA encoding GADD34. We established that the 3' untranslated region of PPP1R15A mRNA contains an active AU-rich element recognized by proteins of the ZFP36 family, promoting its rapid decay under normal conditions and stabilization for efficient expression of GADD34 in response to stress. We identify the tight temporal control of PPP1R15A mRNA turnover as a key step in establishing the ISR molecular memory, which sets the threshold for cellular responsiveness and mediates adaptation to repeated stress conditions.
2024-03-19 | GSE261399 | GEO
Project description:Epigenetic regulations, such as DNA methylation and microRNAs, play an important role in renal fibrosis. Here, we report the regulation of microRNA-219a-2 (mir-219a-2) by DNA methylation in fibrotic kidneys, unveiling the crosstalk between these epigenetic mechanisms. Through genome-wide DNA methylation analysis and pyro-sequencing, we detected the hypermethylation of mir-219a-2 in renal fibrosis induced by unilateral ureter obstruction (UUO) or renal ischemia/reperfusion, which was accompanied by a significant decrease in mir-219a-5p expression. Functionally, overexpression of mir-219a-2 enhanced fibronectin induction during hypoxia or TGF-b1 treatment of cultured renal cells. In mice, inhibition of mir-219a-5p suppressed fibronectin accumulation in UUO kidneys. ALDH1L2 was identified to be the direct target gene of mir-219a-5p in renal fibrosis. Mir-219a-5p suppressed ALDH1L2 expression in cultured renal cells, while inhibition of mir-219a-5p prevented the decrease of ALDH1L2 in UUO kidneys. Knockdown of ALDH1L2 enhanced PAI-1 induction during TGF-b1 treatment of renal cells, which was associated with fibronectin expression. In conclusion, the hypermethylation of mir-219a-2 in response to fibrotic stress attenuates mir-219a-5p expression and induces the up-regulation of its target gene ALDH1L2, which may reduce fibronectin deposition by suppressing PAI-1.
2023-11-01 | GSE236018 | GEO
Project description:Epigenetic regulations, such as DNA methylation and microRNAs, play an important role in renal fibrosis. Here, we report the regulation of microRNA-219a-2 (mir-219a-2) by DNA methylation in fibrotic kidneys, unveiling the crosstalk between these epigenetic mechanisms. Through genome-wide DNA methylation analysis and pyro-sequencing, we detected the hypermethylation of mir-219a-2 in renal fibrosis induced by unilateral ureter obstruction (UUO) or renal ischemia/reperfusion, which was accompanied by a significant decrease in mir-219a-5p expression. Functionally, overexpression of mir-219a-2 enhanced fibronectin induction during hypoxia or TGF-b1 treatment of cultured renal cells. In mice, inhibition of mir-219a-5p suppressed fibronectin accumulation in UUO kidneys. ALDH1L2 was identified to be the direct target gene of mir-219a-5p in renal fibrosis. Mir-219a-5p suppressed ALDH1L2 expression in cultured renal cells, while inhibition of mir-219a-5p prevented the decrease of ALDH1L2 in UUO kidneys. Knockdown of ALDH1L2 enhanced PAI-1 induction during TGF-b1 treatment of renal cells, which was associated with fibronectin expression. In conclusion, the hypermethylation of mir-219a-2 in response to fibrotic stress attenuates mir-219a-5p expression and induces the up-regulation of its target gene ALDH1L2, which may reduce fibronectin deposition by suppressing PAI-1.
2023-11-01 | GSE235842 | GEO
Project description:In response to starvation, cells undergo a metabolic shift to ensure their survival by shutting down protein synthesis and activating catabolic processes, including autophagy, to degrade proteins and recycle nutrients. These processes, however, do require protein synthesis. We asked how this fundamental conflict is resolved. Upon starvation, cells activate the Integrated Stress Response (ISR) and inhibit mammalian target of rapamycin complex 1 (mTORC1). The ISR inhibits protein translation through the phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2), whereas mTORC1 inhibition induces activation of the transcription factors TFEB/TFE3. We discovered that PPP1R15A (aka GADD34), a member of the protein phosphatase 1 complex (PP1) is a direct and early target of TFEB. GADD34 recruits PP1 to dephosphorylate eIF2 and thus fine-tunes protein synthesis to enable translation of the transcriptional program induced by starvation leading to a sustained autophagic flux.
2020-09-30 | PXD016149 | Pride
Project description:Lysosomes are central platforms for not only the degradation of macromolecules but also the integration of multiple signaling pathways. However, whether and how lysosomes mediate the mitochondrial stress response (MSR) remain largely unknown. Here, we demonstrate that lysosomal acidification via the vacuolar H+-ATPase (v-ATPase) is essential for the transcriptional activation of the mitochondrial unfolded protein response (UPRmt). Mitochondrial stress stimulates v-ATPase-mediated lysosomal activation of the mechanistic target of rapamycin complex 1 (mTORC1), which then directly phosphorylates the MSR transcription factor, activating transcription factor 4 (ATF4). Disruption of mTORC1-dependent ATF4 phosphorylation blocks the UPRmt, but not other similar stress responses, such as the UPRER. Finally, ATF4 phosphorylation downstream of the v-ATPase/mTORC1 signaling is indispensable for sustaining mitochondrial redox homeostasis and protecting cells from reactive oxygen species (ROS)-associated cell death upon mitochondrial stress. Thus, v-ATPase/mTORC1-mediated ATF4 phosphorylation via lysosomes links mitochondrial stress to UPRmt activation and mitochondrial function resilience.
2023-06-19 | GSE179510 | GEO
Project description:Reduced eukaryotic Initiation Factor 2 (eIF2)α phosphorylation (p-eIF2α) enhances protein synthesis, memory formation, and addiction-like behaviors. However, p-eIF2α has not been examined with regard to psychoactive cannabinoids and cross-sensitization. Here, we find that a cannabinoid receptor agonist (WIN 55,212-2 mesylate [WIN]) reduced p-eIF2α in vitro by upregulating GADD34 (PPP1R15A), the recruiter of protein phosphatase 1 (PP1). The induction of GADD34 was linked to ERK/CREB signaling and to CREB-binding protein (CBP)-mediated histone hyperacetylation at the Gadd34 locus. In vitro, WIN also upregulated eIF2B1, an eIF2 activator subunit. We next found that WIN administration in vivo reduced p-eIF2α in the nucleus accumbens of adolescent, but not adult, rats. By contrast, WIN increased dorsal striatal levels of eIF2B1 and ΔFosB among both adolescents and adults. In addition, we found cross-sensitization between WIN and cocaine only among adolescents. These findings show that cannabinoids can modulate eukaryotic initiation factors, and they suggest a possible link between p-eIF2α and the gateway drug properties of psychoactive cannabinoids.
2017-08-24 | GSE102946 | GEO
Project description:Turnover of PPP1R15A mRNA encoding GADD34 controls responsiveness and adaptation to cellular stress
| PRJNA1086870 | ENA
Project description:The molecular mechanisms linking the stress of unfolded proteins in the endoplasmic reticulum (ER stress) to glucose intolerance in obese animals are poorly understood. In this study enforced expression of a translation initiation 2α (eIF2α)-specific phosphatase, GADD34, was used to selectively compromise signaling in the eIF2(αP)-dependent arm of the ER unfolded protein response in liver of transgenic mice. The transgene resulted in lower liver glycogen levels and susceptibility to fasting hypoglycemia in lean mice and glucose tolerance and diminished hepato-steatosis in animals fed a high fat diet. Attenuated eIF2(αP) correlated with lower expression of the adipogenic nuclear receptor PPARγ and its upstream regulators, the transcription factors C/EBPα and C/EBPβ, in transgenic mouse liver, whereas eIF2α phosphorylation promoted C/EBP translation in cultured cells and primary hepatocytes. These observations suggest that eIF2(αP)-mediated translation of key hepatic transcriptional regulators of intermediary metabolism contributes to the detrimental consequences of nutrient excess. Keywords: genotype comparison The low expressing Ttr::Fv2E-Perk transgene (#58) was bred into the Atf4 knockout strain and the derivative compound heterozygous mice (in the mixed FvB/n; Swiss Webster background) were backcrossed to the Atf4+/- parental stock and Ttr::Fv2E-PERK positive siblings with Atf4+/+ and Atf4-/- genetypes were analyzed.
2011-12-23 | E-GEOD-11116 | biostudies-arrayexpress
Project description:The molecular mechanisms linking the stress of unfolded proteins in the endoplasmic reticulum (ER stress) to glucose intolerance in obese animals are poorly understood. In this study enforced expression of a translation initiation 2alpha (eIF2a)-specific phosphatase, GADD34, was used to selectively compromise signaling in the eIF2(αP)-dependent arm of the ER unfolded protein response in liver of transgenic mice. The transgene resulted in lower liver glycogen levels and susceptibility to fasting hypoglycemia in lean mice and glucose tolerance and diminished hepato-steatosis in animals fed a high fat diet. Attenuated eIF2(aP) correlated with lower expression of the adipogenic nuclear receptor PPARgamma and its upstream regulators, the transcription factors C/EBPalpha and C/EBPbeta, in transgenic mouse liver, whereas eIF2alpha phosphorylation promoted C/EBP translation in cultured cells and primary hepatocytes. These observations suggest that eIF2(aP)-mediated translation of key hepatic transcriptional regulators of intermediary metabolism contributes to the detrimental consequences of nutrient excess. Keywords: genotype comparison The high expressing Ttr::Fv2E-Perk transgenic mice was injected by either mock or AP20187. Wildtype and Alb::GC transgenic mice were fed by either Low Fat Diet (LFD) or High Fat Diet (HFD) . bred into the Atf4 knockout strain and the derivative compound heterozygous mice (in the mixed FvB/n; Swiss Webster background) were backcrossed to the Atf4+/- parental stock and Ttr::Fv2E-PERK positive siblings with Atf4+/+ and Atf4-/- genetypes were analyzed.
2011-12-23 | E-GEOD-11210 | biostudies-arrayexpress
Project description:Accumulation of misfolded proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), which results in the increased phosphorylation of the eukaryotic initiation factor, eIF2a, and widespread translational repression. Protein synthesis is subsequently restored following the stress-induced transcriptional upregulation of GADD34 (growth arrest and DNA damage transcript 34) protein, a regulator of an eIF2a phosphatase. Genome-wide ribosome foot-printing in WT and GADD34-/- MEFs established that GADD34 mRNA is translated in unstressed cells and identified numerous mRNAs, whose translation was dependent on GADD34 even in the absence of ER stress. Following UPR activation, temporal analyses showed that the translational profile in GADD34-/- MEFs was stalled, displaying a pattern that mirrors the early response to UPR in WT MEFs. Basal GADD34 expression is also required for de-repression of translation and displacement of ER-bound polysomes that occur in early UPR. Thus, the overall UPR response is delayed in the GADD34-/- MEFs, gradually recovering as CReP expression increased. These studies reveal a critical role for basal GADD34 in the propagation of UPR signals in MEFs and mice and suggest that delayed UPR signaling protects GADD34-/- mice from tunicamycin-induced renal toxicity.
2015-10-01 | GSE69800 | GEO