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Cecile Julier - One of the best experts on this subject based on the ideXlab platform.
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Early-onset diabetes mellitus and neurodevelopmental retardation: the first Greek case of Wolcott-Rallison syndrome.
Journal of Pediatric Endocrinology and Metabolism, 2014Co-Authors: Panagiota Triantafyllou, Cecile Julier, Euthymia Vargiami, Isidora Vagianou, Maria Badouraki, Dimitrios I. ZafeiriouAbstract:: Wolcott-Rallison syndrome (WRS) is a very rare genetic disorder, which is transmitted by autosomal recessive inheritance and results from mutations in the gene encoding the eukaryotic initiation factor 2-α kinase-3 (EIF2AK3). The cardinal features of the syndrome include early-onset insulin-dependent diabetes mellitus, multiple epiphyseal dysplasia, and growth retardation. We present the case of a 13-year-old Greek boy with a known history of infancy-onset diabetes mellitus and was found to have WRS at the age of 4 years. He presented with acute liver and renal insufficiency in addition to skeletal dysplasia and neurodevelopmental retardation. The clinical suspicion of WRS was confirmed by molecular analysis of the EIF2AK3 gene. The patient was found to be a compound heterozygote with two different novel mutations (c.2776C>T, p.R902X and c.3038A>G, p.Y989C). The current patient is one of the longer survivors.
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Wolcott-Rallison Syndrome
Orphanet Journal of Rare Diseases, 2010Co-Authors: Cecile Julier, Marc NicolinoAbstract:Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disease, characterized by neonatal/early-onset non-autoimmune insulin-requiring diabetes associated with skeletal dysplasia and growth retardation. Fewer than 60 cases have been described in the literature, although WRS is now recognised as the most frequent cause of neonatal/early-onset diabetes in patients with consanguineous parents. Typically, diabetes occurs before six months of age, and skeletal dysplasia is diagnosed within the first year or two of life. Other manifestations vary between patients in their nature and severity and include frequent episodes of acute liver failure, renal dysfunction, exocrine pancreas insufficiency, intellectual deficit, hypothyroidism, neutropenia and recurrent infections. Bone fractures may be frequent. WRS is caused by mutations in the gene encoding eukaryotic translation initiation factor 2α kinase 3 (EIF2AK3), also known as PKR-like endoplasmic reticulum kinase (PERK). PERK is an endoplasmic reticulum (ER) transmembrane protein, which plays a key role in translation control during the unfolded protein response. ER dysfunction is central to the disease processes. The disease variability appears to be independent of the nature of the EIF2AK3 mutations, with the possible exception of an older age at onset; other factors may include other genes, exposure to environmental factors and disease management. WRS should be suspected in any infant who presents with permanent neonatal diabetes associated with skeletal dysplasia and/or episodes of acute liver failure. Molecular genetic testing confirms the diagnosis. Early diagnosis is recommended, in order to ensure rapid intervention for episodes of hepatic failure, which is the most life threatening complication. WRS should be differentiated from other forms of neonatal/early-onset insulin-dependent diabetes based on clinical presentation and genetic testing. Genetic counselling and antenatal diagnosis is recommended for parents of a WRS patient with confirmed EIF2AK3 mutation. Close therapeutic monitoring of diabetes and treatment with an insulin pump are recommended because of the risk of acute episodes of hypoglycaemia and ketoacidosis. Interventions under general anaesthesia increase the risk of acute aggravation, because of the toxicity of anaesthetics, and should be avoided. Prognosis is poor and most patients die at a young age. Intervention strategies targeting ER dysfunction provide hope for future therapy and prevention.
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wolcott rallison syndrome due to the same mutation w522x in EIF2AK3 in two unrelated families and review of the literature
Pediatric Diabetes, 2010Co-Authors: Nuri M Ozbek, Valérie Senée, Cecile Julier, Sehnaz Aydemir, Damla L Kotan, Neslihan Onenli Mungan, Bilgin Yuksel, Kemal A TopalogluAbstract:Ozbek MN, Senee V, Aydemir S, Kotan LD, Mungan NO, Yuksel B, Julier C, Topaloglu AK. Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature. Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by an early-infancy-onset diabetes mellitus associated with a variety of multisystemic clinical manifestations. Here, we present six patients with WRS, carrying the same homozygous mutation (EIF2AK3-W522X), from two unrelated Turkish families. This is the largest series of patients with the same mutation for this rare syndrome. In this communication we compare clinical features of these six patients with the other 34 patients who have been reported to date, and review the clinical features of WRS. All WRS patients presented first with symptoms of insulin dependent diabetes mellitus, with a mean age at onset of 2 months. All patients had skeletal dysplasia or early signs of it, and growth retardation. Many of the patients with WRS have been reported to have developmental delay, mental retardation, and learning difficulties; in contrast, none of our patients showed abnormal development at age up to 30 months. Acute attacks of hepatic failure were reported in 23 cases out of 37 patients; in 15 of those 23 cases an acute attack of renal failure accompanied the liver failure. Exocrine pancreatic deficiency has been reported in only four cases other than our four patients. Central hypothyroidism was observed in six of 28 cases. We propose that central hypothyroidism is not a component of WRS, but rather a reflection of euthyroid sick syndrome. Four of our patients experienced severe neutropenia, compared to only five of the 27 other cases, suggesting that the W522X mutation may be specifically associated with neutropenia. Other than the consistent features of diabetes mellitus and epiphyseal dysplasia, WRS patients are otherwise characterized by extensive phenotypic variability that correlates poorly to genotype.
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Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature*
Pediatric Diabetes, 2010Co-Authors: M. Nuri Ozbek, Valérie Senée, Cecile Julier, Sehnaz Aydemir, Neslihan Onenli Mungan, Bilgin Yuksel, L. Damla Kotan, A. Kemal TopalogluAbstract:Ozbek MN, Senee V, Aydemir S, Kotan LD, Mungan NO, Yuksel B, Julier C, Topaloglu AK. Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature. Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by an early-infancy-onset diabetes mellitus associated with a variety of multisystemic clinical manifestations. Here, we present six patients with WRS, carrying the same homozygous mutation (EIF2AK3-W522X), from two unrelated Turkish families. This is the largest series of patients with the same mutation for this rare syndrome. In this communication we compare clinical features of these six patients with the other 34 patients who have been reported to date, and review the clinical features of WRS. All WRS patients presented first with symptoms of insulin dependent diabetes mellitus, with a mean age at onset of 2 months. All patients had skeletal dysplasia or early signs of it, and growth retardation. Many of the patients with WRS have been reported to have developmental delay, mental retardation, and learning difficulties; in contrast, none of our patients showed abnormal development at age up to 30 months. Acute attacks of hepatic failure were reported in 23 cases out of 37 patients; in 15 of those 23 cases an acute attack of renal failure accompanied the liver failure. Exocrine pancreatic deficiency has been reported in only four cases other than our four patients. Central hypothyroidism was observed in six of 28 cases. We propose that central hypothyroidism is not a component of WRS, but rather a reflection of euthyroid sick syndrome. Four of our patients experienced severe neutropenia, compared to only five of the 27 other cases, suggesting that the W522X mutation may be specifically associated with neutropenia. Other than the consistent features of diabetes mellitus and epiphyseal dysplasia, WRS patients are otherwise characterized by extensive phenotypic variability that correlates poorly to genotype.
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EIF2AK3 encoding translation initiation factor 2 α kinase 3 is mutated in patients with wolcott rallison syndrome
Nature Genetics, 2000Co-Authors: Marc Delepine, Marc Nicolino, Timothy Barrett, M Golamaully, G M Lathrop, Cecile JulierAbstract:EIF2AK3 , encoding translation initiation factor 2-α kinase 3, is mutated in patients with Wolcott-Rallison syndrome
Douglas R. Cavener - One of the best experts on this subject based on the ideXlab platform.
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PERK Regulates Working Memory and Protein Synthesis-Dependent Memory Flexibility.
PLOS ONE, 2016Co-Authors: Keely Henninger, Barbara C. Mcgrath, Douglas R. CavenerAbstract:PERK (EIF2AK3) is an ER-resident eIF2α kinase required for memory flexibility and metabotropic glutamate receptor-dependent long-term depression, processes known to be dependent on new protein synthesis. Here we investigated PERK’s role in working memory, a cognitive ability that is independent of new protein synthesis, but instead is dependent on cellular Ca2+ dynamics. We found that working memory is impaired in forebrain-specific Perk knockout and pharmacologically PERK-inhibited mice. Moreover, inhibition of PERK in wild-type mice mimics the fear extinction impairment observed in forebrain-specific Perk knockout mice. Our findings reveal a novel role of PERK in cognitive functions and suggest that PERK regulates both Ca2+ -dependent working memory and protein synthesis-dependent memory flexibility.
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insulin secretion and ca2 dynamics in β cells are regulated by perk EIF2AK3 in concert with calcineurin
Journal of Biological Chemistry, 2013Co-Authors: Rong Wang, Barbara C. Mcgrath, Richard F Kopp, Xin Tang, Gong Chen, Douglas R. CavenerAbstract:Protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) (EIF2AK3) is essential for normal development and function of the insulin-secreting β-cell. Although genetic ablation of PERK in β-cells results in permanent neonatal diabetes in humans and mice, the underlying mechanisms remain unclear. Here, we used a newly developed and highly specific inhibitor of PERK to determine the immediate effects of acute ablation of PERK activity. We found that inhibition of PERK in human and rodent β-cells causes a rapid inhibition of secretagogue-stimulated subcellular Ca2+ signaling and insulin secretion. These dysfunctions stem from alterations in store-operated Ca2+ entry and sarcoplasmic endoplasmic reticulum Ca2+-ATPase activity. We also found that PERK regulates calcineurin, and pharmacological inhibition of calcineurin results in similar defects on stimulus-secretion coupling. Our findings suggest that interplay between calcineurin and PERK regulates β-cell Ca2+ signaling and insulin secretion, and that loss of this interaction may have profound implications in insulin secretion defects associated with diabetes.
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PERK in beta cell biology and insulin biogenesis
Trends in Endocrinology and Metabolism, 2010Co-Authors: Douglas R. Cavener, Sounak Gupta, Barbara C. McgrathAbstract:PERK (EIF2AK3) was originally discovered as a major component of the unfolded protein response (UPR). PERK deficiency results in permanent neonatal diabetes, which was initially thought to be caused by a failure to regulate ER stress in insulin-secreting beta cells, culminating in beta cell death. However, subsequent studies found that low beta cell mass was a result of reduced cell proliferation, rather than increased apoptosis. Genetic and cellular studies of Perk-deficient beta cells showed that PERK was crucially required for ER functions including proinsulin trafficking and quality control, unrelated to the ER stress pathway. Under normal physiological conditions, changes in ER calcium levels, mediated by glucose and other insulin secretagogues, regulate PERK activity for the purpose of controlling insulin biogenesis.
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perk EIF2AK3 regulates proinsulin trafficking and quality control in the secretory pathway
Diabetes, 2010Co-Authors: Sounak Gupta, Barbara C. Mcgrath, Douglas R. CavenerAbstract:Abstract Objective: Loss of function mutations in Perk (EIF2AK3) result in permanent neonatal diabetes in humans (Wolcott-Rallison Syndrome) and mice. Previously we found that diabetes associated with Perk -deficiency resulted from insufficient proliferation of β-cells and from defects in insulin secretion. A substantial fraction of PERK-deficient β-cells display a highly abnormal cellular phenotype characterized by grossly distended endoplasmic reticulum (ER) and retention of proinsulin. We investigated over synthesis, lack of Endoplasmic Reticulum Associated Degradation (ERAD) and defects in ER to Golgi trafficking as possible causes. Research Design and Methods: ER functions of PERK were investigated in cell culture and mice in which Perk was impaired or gene dosage modulated. The Ins2 +/Akita mutant mice were used as a model system to test the role of PERK in ERAD. Results: We report that loss of Perk function does not lead to uncontrolled protein synthesis but impaired ER to Golgi anterograde trafficking, retrotranslocation from the ER to the cytoplasm and proteasomal degradation. PERK was also shown to be required to maintain the integrity of the ER and Golgi, and processing of ATF6. Moreover, decreasing Perk dosage surprisingly ameliorates the progression of the Akita mutants towards diabetes. Conclusion: PERK is a positive regulator of ERAD and proteasomal activity. Reducing PERK activity ameliorates the progression of diabetes in the Akita mouse, whereas increasing PERK dosage hastens its progression. We speculate that PERK acts as a metabolic sensor in the insulin-secreting β-cells to modulate the trafficking and quality control of proinsulin in the ER relative to the physiological demands for circulating insulin.
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Translational control and the unfolded protein response.
Antioxidants & Redox Signaling, 2007Co-Authors: Douglas R. CavenerAbstract:Cellular stresses that disrupt the processing of proteins slated for the secretory pathway induce the unfolded protein response (UPR), a regulatory network involving both translational and transcriptional control mechanisms that is designed to expand the secretory pathway and alleviate cellular injury. PERK (PEK/EIF2AK3) mediates the translational control arm of the UPR by enhancing phosphorylation of eIF2. Phosphorylation of eIF2 reduces global protein synthesis, preventing further overload of the secretory pathway and allowing the cell to direct a new pattern of mRNA synthesis that enhances the processing capacity of the endoplasmic reticulum (ER). PERK also directs preferential translation of stress-related transcripts, including that encoding ATF4, a transcriptional activator that contributes to the UPR. Reduced global translation also leads to reduced levels of key regulatory proteins that are subject to rapid turnover, facilitating activation of transcription factors such as NF-B during cellular str...
Valérie Senée - One of the best experts on this subject based on the ideXlab platform.
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A Missense Mutation in PPP1R15B Causes a Syndrome Including Diabetes, Short Stature, and Microcephaly.
Diabetes, 2015Co-Authors: Baroj Abdulkarim, Valérie Senée, Marc Nicolino, Mariana Igoillo-esteve, Mathilde Daures, Sophie Romero, Anne Philippi, Miguel Lopes, Daniel Andrade Da Cunha, Heather P. HardingAbstract:Dysregulated endoplasmic reticulum stress and phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) are associated with pancreatic β-cell failure and diabetes. Here, we report the first homozygous mutation in the PPP1R15B gene (also known as constitutive repressor of eIF2α phosphorylation [CReP]) encoding the regulatory subunit of an eIF2α-specific phosphatase in two siblings affected by a novel syndrome of diabetes of youth with short stature, intellectual disability, and microcephaly. The R658C mutation in PPP1R15B affects a conserved amino acid within the domain important for protein phosphatase 1 (PP1) binding. The R658C mutation decreases PP1 binding and eIF2α dephosphorylation and results in β-cell apoptosis. Our findings support the concept that dysregulated eIF2α phosphorylation, whether decreased by mutation of the kinase (EIF2AK3) in Wolcott-Rallison syndrome or increased by mutation of the phosphatase (PPP1R15B), is deleterious to β-cells and other secretory tissues, resulting in diabetes associated with multisystem abnormalities.
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wolcott rallison syndrome due to the same mutation w522x in EIF2AK3 in two unrelated families and review of the literature
Pediatric Diabetes, 2010Co-Authors: Nuri M Ozbek, Valérie Senée, Cecile Julier, Sehnaz Aydemir, Damla L Kotan, Neslihan Onenli Mungan, Bilgin Yuksel, Kemal A TopalogluAbstract:Ozbek MN, Senee V, Aydemir S, Kotan LD, Mungan NO, Yuksel B, Julier C, Topaloglu AK. Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature. Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by an early-infancy-onset diabetes mellitus associated with a variety of multisystemic clinical manifestations. Here, we present six patients with WRS, carrying the same homozygous mutation (EIF2AK3-W522X), from two unrelated Turkish families. This is the largest series of patients with the same mutation for this rare syndrome. In this communication we compare clinical features of these six patients with the other 34 patients who have been reported to date, and review the clinical features of WRS. All WRS patients presented first with symptoms of insulin dependent diabetes mellitus, with a mean age at onset of 2 months. All patients had skeletal dysplasia or early signs of it, and growth retardation. Many of the patients with WRS have been reported to have developmental delay, mental retardation, and learning difficulties; in contrast, none of our patients showed abnormal development at age up to 30 months. Acute attacks of hepatic failure were reported in 23 cases out of 37 patients; in 15 of those 23 cases an acute attack of renal failure accompanied the liver failure. Exocrine pancreatic deficiency has been reported in only four cases other than our four patients. Central hypothyroidism was observed in six of 28 cases. We propose that central hypothyroidism is not a component of WRS, but rather a reflection of euthyroid sick syndrome. Four of our patients experienced severe neutropenia, compared to only five of the 27 other cases, suggesting that the W522X mutation may be specifically associated with neutropenia. Other than the consistent features of diabetes mellitus and epiphyseal dysplasia, WRS patients are otherwise characterized by extensive phenotypic variability that correlates poorly to genotype.
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Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature*
Pediatric Diabetes, 2010Co-Authors: M. Nuri Ozbek, Valérie Senée, Cecile Julier, Sehnaz Aydemir, Neslihan Onenli Mungan, Bilgin Yuksel, L. Damla Kotan, A. Kemal TopalogluAbstract:Ozbek MN, Senee V, Aydemir S, Kotan LD, Mungan NO, Yuksel B, Julier C, Topaloglu AK. Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature. Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by an early-infancy-onset diabetes mellitus associated with a variety of multisystemic clinical manifestations. Here, we present six patients with WRS, carrying the same homozygous mutation (EIF2AK3-W522X), from two unrelated Turkish families. This is the largest series of patients with the same mutation for this rare syndrome. In this communication we compare clinical features of these six patients with the other 34 patients who have been reported to date, and review the clinical features of WRS. All WRS patients presented first with symptoms of insulin dependent diabetes mellitus, with a mean age at onset of 2 months. All patients had skeletal dysplasia or early signs of it, and growth retardation. Many of the patients with WRS have been reported to have developmental delay, mental retardation, and learning difficulties; in contrast, none of our patients showed abnormal development at age up to 30 months. Acute attacks of hepatic failure were reported in 23 cases out of 37 patients; in 15 of those 23 cases an acute attack of renal failure accompanied the liver failure. Exocrine pancreatic deficiency has been reported in only four cases other than our four patients. Central hypothyroidism was observed in six of 28 cases. We propose that central hypothyroidism is not a component of WRS, but rather a reflection of euthyroid sick syndrome. Four of our patients experienced severe neutropenia, compared to only five of the 27 other cases, suggesting that the W522X mutation may be specifically associated with neutropenia. Other than the consistent features of diabetes mellitus and epiphyseal dysplasia, WRS patients are otherwise characterized by extensive phenotypic variability that correlates poorly to genotype.
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wolcott rallison syndrome clinical genetic and functional study of EIF2AK3 mutations and suggestion of genetic heterogeneity
Diabetes, 2004Co-Authors: Valérie Senée, Krishna M. Vattem, Marc Delepine, Lynn A. Rainbow, Céline Haton, Annick Lecoq, Nick Shaw, Jean J. Robert, R. P. Rooman, Catherine DiatloffzitoAbstract:Wolcott-Rallison syndrome (WRS) is a rare autosomal-recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple epiphyseal dysplasia and growth retardation, and other variable multisystemic clinical manifestations. Based on genetic studies of two inbred families, we previously identified the gene responsible for this disorder as EIF2AK3 , the pancreatic eukaryotic initiation factor 2α (eIF2α) kinase. Here, we have studied 12 families with WRS, totalling 18 cases. With the exception of one case, all patients carried EIF2AK3 mutations resulting in truncated or missense versions of the protein. Exclusion of EIF2AK3 mutations in the one patient case was confirmed by both linkage and sequence data. The activities of missense versions of EIF2AK3 were characterized in vivo and in vitro and found to have a complete lack of activity in four mutant proteins and residual kinase activity in one. Remarkably, the onset of diabetes was relatively late (30 months) in the patient expressing the partially defective EIF2AK3 mutant and in the patient with no EIF2AK3 involvement (18 months) compared with other patients (<6 months). The patient with no EIF2AK3 involvement did not have any of the other variable clinical manifestations associated with WRS, which supports the idea that the genetic heterogeneity between this variant form of WRS and EIF2AK3 WRS correlates with some clinical heterogeneity.
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Wolcott-Rallison Syndrome: Clinical, Genetic, and Functional Study of EIF2AK3 Mutations and Suggestion of Genetic Heterogeneity
Diabetes, 2004Co-Authors: Valérie Senée, Krishna M. Vattem, Marc Delepine, Lynn A. Rainbow, Céline Haton, Annick Lecoq, Nick Shaw, Jean J. Robert, R. P. Rooman, Catherine Diatloff-zitoAbstract:Wolcott-Rallison syndrome (WRS) is a rare autosomal-recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple epiphyseal dysplasia and growth retardation, and other variable multisystemic clinical manifestations. Based on genetic studies of two inbred families, we previously identified the gene responsible for this disorder as EIF2AK3 , the pancreatic eukaryotic initiation factor 2α (eIF2α) kinase. Here, we have studied 12 families with WRS, totalling 18 cases. With the exception of one case, all patients carried EIF2AK3 mutations resulting in truncated or missense versions of the protein. Exclusion of EIF2AK3 mutations in the one patient case was confirmed by both linkage and sequence data. The activities of missense versions of EIF2AK3 were characterized in vivo and in vitro and found to have a complete lack of activity in four mutant proteins and residual kinase activity in one. Remarkably, the onset of diabetes was relatively late (30 months) in the patient expressing the partially defective EIF2AK3 mutant and in the patient with no EIF2AK3 involvement (18 months) compared with other patients ( EIF2AK3 involvement did not have any of the other variable clinical manifestations associated with WRS, which supports the idea that the genetic heterogeneity between this variant form of WRS and EIF2AK3 WRS correlates with some clinical heterogeneity.
Ji Wang - One of the best experts on this subject based on the ideXlab platform.
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silica nanoparticles induce autophagosome accumulation via activation of the EIF2AK3 and atf6 upr pathways in hepatocytes
Autophagy, 2018Co-Authors: Ji Wang, Yang Li, Junchao Duan, Man Yang, Yang Yu, Lin Feng, Xiaozhe Yang, Xianqing Zhou, Zhendong ZhaoAbstract:Autophagy dysfunction is a potential toxic effect of nanoparticles. Previous studies have indicated that silica nanoparticles (SiNPs) induce macroautophagy/autophagy dysfunction, while the precise mechanisms remain uncertain. Hence, the present study investigated the molecular mechanisms by which SiNPs enhanced autophagosome synthesis, which then contributed to autophagy dysfunction. First, the effects of SiNPs on autophagy and autophagic flux were verified using transmission electron microscopy, laser scanning confocal microscopy, and western blot assays. Then, the activation of endoplasmic reticular (ER) stress was validated to be through the EIF2AK3 and ATF6 UPR pathways but not the ERN1-XBP1 pathway, along with the upregulation of downstream ATF4 and DDIT3. Thereafter, the ER stress inhibitor 4-phenylbutyrate (4-PBA) was used to verify that SiNP-induced autophagy could be influenced by ER stress. Furthermore, specialized lentiviral shRNA were employed to determine that autophagy was induced vi...
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hepatitis c virus core protein activates autophagy through EIF2AK3 and atf6 upr pathway mediated map1lc3b and atg12 expression
Autophagy, 2014Co-Authors: Ji Wang, Rongyan Kang, He Huang, Xueyan Xi, Bei Wang, Zhendong ZhaoAbstract:HCV infection induces autophagy, but how this occurs is unclear. Here, we report the induction of autophagy by the structural HCV core protein and subsequent endoplasmic reticular (ER) stress in Huh7 hepatoma cells. During ER stress, both the EIF2AK3 and ATF6 pathways of the unfolded protein response (UPR) were activated by HCV core protein. Then, these pathways upregulated transcription factors ATF4 and DDIT3. The ERN1-XBP1 pathway was not activated. Through ATF4 in the EIF2AK3 pathway, the autophagy gene ATG12 was upregulated. DDIT3 upregulated the transcription of autophagy gene MAP1LC3B (LC3B) by directly binding to the –253 to –99 base region of the LC3B promoter, contributing to the development of autophagy. Collectively, these data suggest not only a novel role for the HCV core protein in autophagy but also offer new insight into detailed molecular mechanisms with respect to HCV-induced autophagy, specifically how downstream UPR molecules regulate key autophagic gene expression.
Venkatesan Radha - One of the best experts on this subject based on the ideXlab platform.
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EIF2AK3 mutations in south indian children with permanent neonatal diabetes mellitus associated with wolcott rallison syndrome
Pediatric Diabetes, 2014Co-Authors: Suresh Jahnavi, Viswanathan Mohan, Varadarajan Poovazhagi, Sekar Kanthimathi, Vijay Gayathri, Venkatesan RadhaAbstract:Objective This study describes the clinical and genetic evaluation of permanent neonatal diabetes due to Wolcott–Rallison syndrome (WRS) in south Indian consanguineous families. We aimed to evaluate the genetic basis of the disease in eight children with WRS from five South Indian families. Patients and methods We studied eight children who presented with permanent neonatal diabetes from five South Indian families. Follow up clinical evaluation revealed features (like liver disease, skeletal dysplasia, and thyroid dysfunction) suggestive of WRS. All the coding exons along with splice sites of KCNJ11, ABCC8, INS, GCK and EIF2AK3 genes were sequenced in all the probands. Results Two novel homozygous mutations (Trp658Ser, c.3150+1G>T) and one known homozygous mutation (Arg1065*, c.3193C>T) in EIF2AK3 gene were identified in children with WRS. Mutation Arg1065*was identified in four children. Conclusions Our results in these families show that the mutations in homozygous state are likely to be causative. We suggest the screening for EIF2AK3 gene mutations as WRS is now recognized as the most frequent cause of neonatal diabetes in children with consanguineous parents. As the mode of inheritance is recessive, screening for genetic mutations becomes important to aid in risk prediction and clinical management.
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EIF2AK3 mutations in South Indian children with permanent neonatal diabetes mellitus associated with Wolcott–Rallison syndrome
Pediatric Diabetes, 2013Co-Authors: Suresh Jahnavi, Viswanathan Mohan, Varadarajan Poovazhagi, Sekar Kanthimathi, Vijay Gayathri, Venkatesan RadhaAbstract:Objective This study describes the clinical and genetic evaluation of permanent neonatal diabetes due to Wolcott–Rallison syndrome (WRS) in south Indian consanguineous families. We aimed to evaluate the genetic basis of the disease in eight children with WRS from five South Indian families. Patients and methods We studied eight children who presented with permanent neonatal diabetes from five South Indian families. Follow up clinical evaluation revealed features (like liver disease, skeletal dysplasia, and thyroid dysfunction) suggestive of WRS. All the coding exons along with splice sites of KCNJ11, ABCC8, INS, GCK and EIF2AK3 genes were sequenced in all the probands. Results Two novel homozygous mutations (Trp658Ser, c.3150+1G>T) and one known homozygous mutation (Arg1065*, c.3193C>T) in EIF2AK3 gene were identified in children with WRS. Mutation Arg1065*was identified in four children. Conclusions Our results in these families show that the mutations in homozygous state are likely to be causative. We suggest the screening for EIF2AK3 gene mutations as WRS is now recognized as the most frequent cause of neonatal diabetes in children with consanguineous parents. As the mode of inheritance is recessive, screening for genetic mutations becomes important to aid in risk prediction and clinical management.
