T3 and Glucose Increase Expression of Phosphoenolpyruvate Carboxykinase (Pck1) Leading to Increased ß-Cell Proliferation
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE218334 | GEO | 2023/11/18
REPOSITORIES: GEO
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Project description:T3 and Glucose Increase Expression of Phosphoenolpyruvate Carboxykinase (Pck1) Leading to Increased ß-Cell Proliferation
| PRJNA903166 | ENA
Project description:ObjectivesThyroid hormone (T3) and high glucose concentrations are critical components of β-cell maturation and function. In the present study, we asked whether T3 and glucose signaling pathways coordinately regulate transcription of genes important for β-cell function and proliferation.MethodsRNA-seq analysis was performed on cadaveric human islets from five different donors in response to low and high glucose concentrations and in the presence or absence of T3. Gene expression was also studies in sorted human β-cells, mouse islets and Ins-1 cells by RT-qPCR. Silencing of the thyroid hormone receptors (THR) was conducted using lentiviruses. Proliferation was assessed by ki67 immunostaining in primary human/mouse islets. Chromatin immunoprecipitation and proximity ligation assay were preformed to validate interactions of ChREBP and THR.ResultsWe found glucose-mediated expression of carbohydrate response element binding protein alpha and beta (ChREBPα and ChREBPβ) mRNAs and their target genes are highly dependent on T3 concentrations in rodent and human β-cells. In β-cells, T3 and glucose coordinately regulate the expression of ChREBPβ and PCK1 (phosphoenolpyruvate carboxykinase-1) among other important genes for β-cell maturation. Additionally, we show the thyroid hormone receptor (THR) and ChREBP interact, and their relative response elements are located near to each other on mutually responsive genes. In FACS-sorted adult human β-cells, we found that high concentrations of glucose and T3 induced the expression of PCK1. Next, we show that overexpression of Pck1 together with dimethyl malate (DMM), a substrate precursor, significantly increased β-cell proliferation in human islets. Finally, using a Cre-Lox approach, we demonstrated that ChREBPβ contributes to Pck1-dependent β-cell proliferation in mouse β-cells.ConclusionsWe conclude that T3 and glucose act together to regulate ChREBPβ, leading to increased expression and activity of Pck1, and ultimately increased β-cell proliferation.
| S-EPMC9731891 | biostudies-literature
Project description:Acetylation is known to regulate the activity of cytosolic phosphoenolpyruvate carboxykinase (PCK1), a key enzyme in gluconeogenesis, by promoting the reverse reaction of the enzyme (converting phosphoenolpyruvate to oxaloacetate). It is also known that the histone acetyltransferase p300 can induce PCK1 acetylation in cells, but whether that is a direct or indirect function was not known. Here we initially set out to determine whether p300 can acetylate directly PCK1 in vitro. We report that p300 weakly acetylates PCK1, but surprisingly, using several techniques including protein crystallization, mass spectrometry, isothermal titration calorimetry, saturation-transfer difference nuclear magnetic resonance and molecular docking, we found that PCK1 is also able to acetylate itself using acetyl-CoA independently of p300. This reaction yielded an acetylated recombinant PCK1 with a 3-fold decrease in kcat without changes in Km for all substrates. Acetylation stoichiometry was determined for 14 residues, including residues lining the active site. Structural and kinetic analyses determined that site-directed acetylation of K244, located inside the active site, altered this site and rendered the enzyme inactive. In addition, we found that acetyl-CoA binding to the active site is specific and metal dependent. Our findings provide direct evidence for acetyl-CoA binding and chemical reaction with the active site of PCK1 and suggest a newly discovered regulatory mechanism of PCK1 during metabolic stress.
| S-EPMC7948413 | biostudies-literature
Project description:Bats are an ideal mammalian group for exploring adaptations to fasting due to their large variety of diets and because fasting is a regular part of their life cycle. Mammals fed on a carbohydrate-rich diet experience a rapid decrease in blood glucose levels during a fast, thus, the development of mechanisms to resist the consequences of regular fasts, experienced on a daily basis, must have been crucial in the evolution of frugivorous bats. Phosphoenolpyruvate carboxykinase 1 (PEPCK1, encoded by the Pck1 gene) is the rate-limiting enzyme in gluconeogenesis and is largely responsible for the maintenance of glucose homeostasis during fasting in fruit-eating bats. To test whether Pck1 has experienced adaptive evolution in frugivorous bats, we obtained Pck1 coding sequence from 20 species of bats, including five Old World fruit bats (OWFBs) (Pteropodidae) and two New World fruit bats (NWFBs) (Phyllostomidae). Our molecular evolutionary analyses of these sequences revealed that Pck1 was under purifying selection in both Old World and New World fruit bats with no evidence of positive selection detected in either ancestral branch leading to fruit bats. Interestingly, however, six specific amino acid substitutions were detected on the ancestral lineage of OWFBs. In addition, we found considerable evidence for parallel evolution, at the amino acid level, between the PEPCK1 sequences of Old World fruit bats and New World fruit bats. Test for parallel evolution showed that four parallel substitutions (Q276R, R503H, I558V and Q593R) were driven by natural selection. Our study provides evidence that Pck1 underwent parallel evolution between Old World and New World fruit bats, two lineages of mammals that feed on a carbohydrate-rich diet and experience regular periods of fasting as part of their life cycle.
| S-EPMC4373879 | biostudies-literature
Project description:BackgroundIn metabolic stress, the cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) enzyme is involved in energy production through the gluconeogenesis pathway. PEPCK-C deficiency is a rare childhood-onset autosomal recessive metabolic disease caused by PCK1 genetic defects. Previous studies showed a broad clinical spectrum ranging from asymptomatic to recurrent hypoglycemia with/without lactic acidosis, encephalopathy, seizures, and liver failure.ResultsIn this article, we discuss the occurrence of PEPCK-C deficiency in four families from the United Arab Emirates and Oman. All patients presented with unexplained hypoglycemia as a common feature. Two out of the seven patients presented with episodes of encephalopathy that resulted in seizures and neuroregression leading to global developmental delay and one patient had a neonatal presentation. Observed biochemical abnormalities include elevated lactate, transaminases, and tricarboxylic acid cycle metabolites in most patients. Elevated creatine kinase was documented in two patients. Whole exome sequencing revealed two novel (c.574T > C, and c.1268 C > T) and a previously reported splice site (c.961 + 1G > A) PCK1 variant in the affected families.ConclusionPatients become vulnerable during intercurrent illness; thus, prevention and prompt reversal of a catabolic state are crucial to avoid irreversible brain damage. This report will help to expand the clinical understanding of this rare disease and recommends screening for PEPCK-C deficiency in unexplained hypoglycemia.
| S-EPMC10625263 | biostudies-literature
Project description:The aim of this study was to investigate the role of the cytosolic form of phosphoenolpyruvate carboxykinase (Pck1) in the development of insulin resistance. Previous studies have shown that the roles of Pck1 in white adipose tissue (WAT) in glyceroneogenesis and reesterification of free fatty acids (FFA) to generate triglyceride are vital for the prevention of diabetes. We hypothesized that insulin resistance develops when dysregulation of Pck1 occurs in the triglyceride/fatty acid cycle, which regulates lipid synthesis and transport between adipose tissue and the liver. We examined this by analyzing mice with a deletion of the PPARgamma binding site in the promoter of Pck1 (PPARE(-/-)). This mutation reduced the fasting Pck1 mRNA expression in WAT in brown adipose tissue (BAT). To analyze insulin resistance, we performed hyperinsulinemic-euglycemic glucose clamp analyses. PPARE(-/-) mice were profoundly insulin resistant and had more FFA and glycerol released during the hyperinsulinemic-euglycemic clamp compared with wild-type mice (WT). Finally, we analyzed insulin secretion in isolated islets. We found a 2-fold increase in insulin secretion in the PPARE(-/-) mice at 16.7 mM glucose. Thus, the PPARE site in the Pck1 promoter is essential for maintenance of lipid metabolism and glucose homeostasis and disease prevention.
| S-EPMC3035508 | biostudies-literature
Project description:Phosphoenolpyruvate carboxykinase (Pck1) is a metabolic enzyme that is integral to the gluconeogenic and glyceroneogenic pathways. However, Pck1's role in macrophage metabolism and function is unknown. Using stable isotopomer MS analysis in a mouse model with a myeloid cell-specific Pck1 deletion, we show here that this deletion increases the proinflammatory phenotype in macrophages. Incubation of LPS-stimulated bone marrow-derived macrophages (BMDM) with [U-13C]glucose revealed reduced 13C labeling of citrate and malate and increased 13C labeling of lactate in Pck1-deleted bone marrow-derived macrophages. We also found that the Pck1 deletion in the myeloid cells increases reactive oxygen species (ROS). Of note, this altered macrophage metabolism increased expression of the M1 cytokines TNFα, IL-1β, and IL-6. We therefore conclude that Pck1 contributes to M1 polarization in macrophages. Our findings provide important insights into the factors determining the macrophage inflammatory response and indicate that Pck1 activity contributes to metabolic reprogramming and polarization in macrophages.
| S-EPMC5836109 | biostudies-literature
Project description:Cancer cells must adapt metabolically to survive and proliferate when nutrients are limiting. Here we used combined transcriptional-metabolomic network analysis to identify metabolic pathways that support glucose-independent tumor cell growth. We found that glucose deprivation stimulated the re-wiring of the tricarboxylic acid (TCA) cycle and co-opting early steps of gluconeogenesis to promote cell proliferation under low glucose. Glucose limitation promoted the production of phosphoenolpyruvate (PEP) from glutamine, which was used to fuel biosynthetic pathways normally sustained by glucose, including serine and purine biosynthesis. Mitochondrial PEP-carboxykinase (PCK2) was required for this glutamine-dependent metabolic reprogramming. PCK2 expression was dependent on the hypoxia-inducible factors (HIFs), and required to maintain tumor cell proliferation under limiting glucose availability. Elevated PCK2 expression is observed in several human tumor types, and enriched in tumor tissue from non-small cell lung cancer (NSCLC) patients. Our results define a novel role for PCK2 in cancer cell metabolic reprogramming that promotes glucose-independent cell growth and metabolic stress resistance in human tumors.
2015-10-15 | GSE66556 | GEO
Project description:Neddylation is a post-translational mechanism that adds a ubiquitin-like protein, namely neural precursor cell expressed developmentally down-regulated protein 8, to target proteins, with yet-unknown consequences. Here we show in mice that neddylation in liver is modulated by nutrient availability. Inhibition of neddylation in mouse liver (either pharmacologically or genetically) reduces gluconeogenic capacity and the hyperglycemic actions of counterregulatory hormones (glucagon, adrenaline and glucocorticoids). Further, people with obesity and type 2 diabetes (compared to people with obesity and normoglycemia) display elevated hepatic neddylation levels that correlate positively with fasting glucose levels. Mechanistically, we determined that fasting or caloric restriction of mice leads to neddylation of phosphoenolpyruvate carboxykinase 1 (PCK1) at three lysine residues—K278, K342 and K387. PCK1 is a key control point for gluconeogenesis regulation that can be post-translationally modified by acetylation and phosphorylation, but to date no modifications are known to affect its gluconeogenic capacity. Of note, we find that mutating the three PCK1 lysines that are neddylated reduces its gluconeogenic activity rate. Molecular dynamics simulations show that neddylation of PCK1 could re-position two loops surrounding the catalytic center into an open configuration, rendering the catalytic center more accessible. Our study reveals that neddylation of PCK1 provides a finely-tuned mechanism of controlling glucose metabolism by linking whole nutrient availability to metabolic homeostasis.
2023-10-08 | PXD043054 | Pride
Project description:Bacillus sp. T3 strain:T3 Genome sequencing
| PRJNA1012702 | ENA