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The expression of eukaryotic translation initiation factor-2 subunit 3 (EIF2S3) in patients with non-small cell lung and colorectal cancer is lower than that in healthy individuals. However, the functions of EIF2S3 remain unclear, and its study in leukemia has not been reported. The article aims to explore the role of EIF2S3 in AML (acute myeloid leukemia) and its underlying mechanism. Reverse transcription-quantitative PCR was performed to evaluate the expression levels of EIF2S3, and its association with patient prognosis was determined. Inducible HEL-EIF2S3 and HL-60-EIF2S3 cell lines were established by retrovirus infection. Cellular proliferation and the cell cycle were analyzed using Cell Counting Kit-8 and flow cytometric analyses. Tumorigenic ability was evaluated using xenograft nude mouse model. Gene expression profiles were analyzed in HL-60-EIF2S3 cells by next-generation sequencing, and WB analysis was performed to detect the expression of related proteins. The expression of EIF2S3 in patients with AML was lower than that experiencing CR (P = 0.02). Furthermore, EIF2S3 overexpression inhibited cellular proliferation, halted G0/1 to S phase cell cycle progression, and inhibited tumorigenicity (P = 0.015). 479 differentially expressed genes were identified between HL60-EIF2S3 DOX (−) and HL60-EIF2S3 DOX ( +) cells via NGS and several of them involved in MAPK/ERK signaling pathway. The phosphorylation levels of ERK decreased when EIF2S3 was overexpressed (P

Mental deficiency, epilepsy, hypogonadism, microcephaly and obesity (MEHMO) syndrome is a severe X-linked syndrome caused by pathogenic variants in EIF2S3. The gene encodes the γ subunit of the eukaryotic translation initiation factor-2, eIF2, essential for protein translation. A recurrent frameshift variant is described in severely affected patients while missense variants usually cause a moderate phenotype. We identified a novel missense variant (c.433A>G, p.(Met145Val)) in EIF2S3 in a mildly affected patient. Studies on zebrafish confirm the pathogenicity of this novel variant and three previously published missense variants. CRISPR/Cas9 knockout of eif2s3 in zebrafish embryos recapitulate the human microcephaly and show increased neuronal cell death. Abnormal high glucose levels were identified in mutant embryos, caused by beta cell and pancreatic progenitor deficiency, not related to apoptosis. Additional studies in patient-derived fibroblasts did not reveal apoptosis. Our results provide new insights into disease physiopathology, suggesting tissue-dependant mechanisms. This article is protected by copyright. All rights reserved.

MEHMO syndrome is a rare X-linked syndrome characterized by Mental retardation, Epilepsy, Hypogenitalism, Microcephaly, and Obesity associated with the defect of protein synthesis caused by the EIF2S3 gene mutations. We hypothesized that the defect in protein synthesis could have an impact on the immune system. We describe immunologic phenotype and possible treatment outcomes in patient with MEHMO syndrome carrying a frame-shift mutation (I465fs) in the EIF2S3 gene. The proband (currently 9-year-old boy) had normal IgG and IgM levels, but had frequent respiratory and urinary tract infections. On subcutaneous immunoglobulin therapy achieving supra-physiological IgG levels the frequency of infections significantly decreased in Poisson regression by 54.5 % (CI 33.2-89.7, p=0.017). The MEHMO patient had had frequent acute infections despite normal IgG and IgM serum levels and responded well to the immunoglobulin treatment.

Rare pathogenic EIF2S3 missense and terminal deletion variants cause the X-linked intellectual disability (ID) syndrome MEHMO, or a milder phenotype including pancreatic dysfunction and hypopituitarism. We present two unrelated male patients who carry novel EIF2S3 pathogenic missense variants (p.(Thr144Ile) and p.(Ile159Leu)) thereby broadening the limited genetic spectrum and underscoring clinically variable expressivity of MEHMO. While the affected male with p.(Thr144Ile) presented with severe motor delay, severe microcephaly, moderate ID, epileptic seizures responsive to treatments, hypogenitalism, central obesity, facial features, and diabetes, the affected male with p.(Ile159Leu) presented with moderate ID, mild motor delay, microcephaly, epileptic seizures resistant to treatment, central obesity, and mild facial features. Both variants are located in the highly conserved guanine nucleotide binding domain of the EIF2S3 encoded eIF2γ subunit of the heterotrimeric translation initiation factor 2 (eIF2) complex. Further, we investigated both variants in a structural model and in yeast. The reduced growth rates and lowered fidelity of translation with increased initiation at non-AUG codons observed for both mutants in these studies strongly support pathogenicity of the variants.

Background/aim: The aim of the study is to assess expression levels of CPEB4, APC, TRIP13, EIF2S3, EIF4A1, IFNg, PIK3CA and CTNNB1 genes in tumors and peripheral bloods of colorectal cancer patients in stages I–IV.\ud \ud Materials and methods: The mRNA levels of the genes were determined in tumor tissues and peripheral blood samples of 45 colorectal cancer patients and colon tissues and peripheral blood samples of 5 healthy individuals. Real-time polymerase chain reaction method was used for the analysis.\ud \ud Results: The mRNA level of the CPEB4 gene was significantly downregulated in colorectal tumor tissues and was upregulated in the peripheral blood of colorectal cancer patients relative to the controls (P < 0.05). APC mRNA level was significantly downregulated in tissues and upregulated in the peripheral blood (P < 0.05). TRIP13 mRNA level was upregulated in peripheral blood and also significantly upregulated in colorectal tumor tissues (P < 0.05). EIF2S3 mRNA level was upregulated in tissues and also significantly upregulated in peripheral blood (P < 0.05). PIK3CA mRNA level was downregulated in tissues and upregulated in peripheral blood. EIF4A1 mRNA level was downregulated in tissues and significantly upregulated in peripheral blood (P < 0.05). CTNNB1 mRNA level was downregulated in tissues and upregulated in peripheral blood. IFNg mRNA level was upregulated in both colorectal cancer tumor tissues and peripheral blood.\ud \ud Conclusion: TRIP13 and CPEB4 mRNA up regulation in the peripheral blood of patients with colorectal cancer may be a potential target for early stage diagnosis. In addition to this evaluation, although there is not much study on EIF2S3 and EIF4A1 mRNA changes in cases with colorectal cancer, upregulation in peripheral blood draws attention in our study. These data will shed light on the new comprehensive studies.

Human immunodeficiency viruses type 1 and 2 (HIV-1 and HIV-2) are the causative agents of the acquired immunodeficiency syndrome (AIDS). While both viruses share a similar structural and genomic organization, a difference in replication dynamics and the clinical course of infection is evident between the two. Patients dually infected were shown to have lower viral loads and generally a slower rate of progression to AIDS than those who are mono-infected. While the roles of the unique accessory proteins have been studied in detail for HIV-1, those of HIV-2, including viral protein X (Vpx), remain largely uncharacterized. In our previous experiments, Vpx of HIV-2 was found to be involved in decreasing the infectivity of HIV-1 in dual infection cell culture assays. We set out to elucidate the function of this accessory protein, identifying protein–protein interactions of HIV-2 Vpx with cellular and possibly HIV-1 proteins in dual infection, using in-vitro proteomics techniques and proximity ligation assays. Results showed that wild-type Vpx interacted with many cellular proteins involved in splicing, packaging of pre-mRNA, nuclear export, and translation. Of particular interest was the interaction between HIV-2 Vpx and the pre-mRNA-splicing factor ATP-dependent RNA helicase DHX15, which is required for HIV-1 viral DNA synthesis, and the eukaryotic translation initiation factor 2 subunit 3 (EIF2S3), involved in the early steps of protein synthesis. Additionally, Vpx was found to interact directly with the cellular transcriptional repressor C-Terminal Binding Protein 2 (CTBP-2). Moreover, Vpx was shown to hinder the function of HIV-1 reverse transcriptase in in-vitro assays. These findings shed light on the functions of this accessory protein and add to our understanding of the replication dynamics of HIV-2 and its role in dual infection.

Newcastle disease virus (NDV) replication depends on the translation machinery of the host cell; therefore, the eukaryotic translation initiation factor 2 (eIF2) gene family is a likely candidate for control of viral replication. We hypothesized that differential expression of host genes related to translation and innate immune response could contribute to differential resistance to NDV in inbred Fayoumi and Leghorn lines. The expression of twenty-one genes related to the interferon signaling pathway and the eIF2 family was evaluated at two- and six-days post infection (dpi) in the spleen from both lines, either challenged by NDV or nonchallenged. Higher expression of OASL in NDV challenged versus nonchallenged spleen was observed in Leghorns at 2 dpi. Lower expression of EIF2B5 was found in NDV challenged than nonchallenged Fayoumis and Leghorns at 2 dpi. At 2 dpi, NDV challenged Fayoumis had lower expression of EIF2B5 and EIF2S3 than NDV challenged Leghorns. At 6 dpi, NDV challenged Fayoumis had lower expression of EIF2S3 and EIF2B4 than NDV challenged Leghorns. The genetic line differences in expression of eIF2-related genes may contribute to their differential resistance to NDV and also to understanding the interaction between protein synthesis shut-off and virus control in chickens.

Nonalcoholic fatty liver disease (NAFLD) is a common disorder hallmarked by excessive lipid deposits. Based on our recent research on lipid droplet (LD) formation in hepatocytes, we investigated LD-associated gene regulations in NAFLD of different grades, that is, steatosis vs steatohepatitis by comparing liver biopsies from healthy controls (N = 13) and NAFLD patients (N = 102). On average, more than 700 differentially expressed genes (DEGs) were identified of which 146 are mechanistically linked to LD formation. We identified 51 LD-associated DEGs frequently regulated in patient samples (range ≥5 to ≤102) with the liver-receptor homolog-1(NR5A2), that is, a key regulator of cholesterol metabolism being commonly repressed among 100 patients examined. With bland steatosis, notable regulations involved hypoxia-inducible lipid droplet-associated-protein and diacylglycerol-O-acyltransferase-2 renowned for their role in LD-growth. Conversely, nonalcoholic steatohepatitis-associated DEGs coded for epidermal growth factor receptor and TLR4 signaling with decreased expression of the GTPase Rab5 and the lipid phosphohydrolase PPAP2B thus highlighting adaptive responses to inflammation, LDL-mediated endocytosis and lipogenesis, respectively. Studies with steatotic primary human hepatocyte cultures demonstrated induction of LD-associated PLIN2, CIDEC, DNAAF1, whereas repressed expression of CPT1A, ANGPTL4, and PKLR informed on burdened mitochondrial metabolism. Equally, repressed expression of the B-lymphocyte chemoattractant CXCL13 and STAT4 as well as induced FGF21 evidenced amelioration of steatosis-related inflammation. In-vitro/in-vivo patient sample comparisons confirmed C-reactive protein, SOCS3, NR5A2, and SOD2 as commonly regulated. Lastly, STRING network analysis highlighted potential "druggable" targets with PLIN2, CIDEC, and hypoxia-inducible lipid droplet-associated-protein being confirmed by immunofluorescence microscopy. In conclusion, steatosis and steatohepatitis specific gene regulations informed on the pathogenesis of NAFLD to broaden the perspective of targeted therapies.

Summary Dysregulation of cellular protein synthesis is linked to a variety of diseases. Mutations in EIF2S3, encoding the γ subunit of the heterotrimeric eukaryotic translation initiation factor eIF2, cause MEHMO syndrome, an X-linked intellectual disability disorder. Here, using patient-derived induced pluripotent stem cells, we show that a mutation at the C terminus of eIF2γ impairs CDC123 promotion of eIF2 complex formation and decreases the level of eIF2-GTP-Met-tRNAiMet ternary complexes. This reduction in eIF2 activity results in dysregulation of global and gene-specific protein synthesis and enhances cell death upon stress induction. Addition of the drug ISRIB, an activator of the eIF2 guanine nucleotide exchange factor, rescues the cell growth, translation, and neuronal differentiation defects associated with the EIF2S3 mutation, offering the possibility of therapeutic intervention for MEHMO syndrome.

The heterotrimeric eukaryotic translation initiation factor (eIF) 2 plays critical roles in delivering initiator Met-tRNAiMet to the 40S ribosomal subunit and in selecting the translation initiation site. Genetic analyses of patients with MEHMO syndrome, an X-linked intellectual disability syndrome, have identified several unique mutations in the EIF2S3 gene that encodes the γ subunit of eIF2. To gain insights into the molecular consequences of MEHMO syndrome mutations on eIF2 function, we generated a yeast model of the human eIF2γ-I259M mutant, previously identified in a patient with MEHMO syndrome. The corresponding eIF2γ-I318M mutation impaired yeast cell growth and derepressed GCN4 expression, an indicator of defective eIF2–GTP–Met-tRNAiMet complex formation, and, likewise, overexpression of human eIF2γ-I259M derepressed ATF4 messenger RNA translation in human cells. The yeast eIF2γ-I318M mutation also increased initiation from near-cognate start codons. Biochemical analyses revealed a defect in Met-tRNAiMet binding to the mutant yeast eIF2 complexes in vivo and in vitro. Overexpression of tRNAiMet restored Met-tRNAiMet binding to eIF2 in vivo and rescued the growth defect in the eIF2γ-I318M strain. Based on these findings and the structure of eIF2, we propose that the I259M mutation impairs Met-tRNAiMet binding, causing altered control of protein synthesis that underlies MEHMO syndrome.

Impairment of translation initiation and its regulation within the integrated stress response (ISR) and related unfolded-protein response has been identified as a cause of several multi-systemic syndromes. Here we link MEHMO syndrome, whose genetic etiology was unknown, to this group of disorders. MEHMO is a rare X-linked syndrome characterized by profound intellectual disability, epilepsy, hypogonadism, and hypogenitalism, microcephaly, and obesity. We have identified a C-terminal frameshift mutation (Ile465Serfs) in the EIF2S3 gene in three families with MEHMO syndrome and a novel maternally inherited missense EIF2S3 variant (Ser108Arg) in another male patient with less severe clinical symptoms. The EIF2S3 gene encodes the γ subunit of eukaryotic translation initiation factor 2 (eIF2), crucial for initiation of protein synthesis and regulation of the ISR. Studies in patient fibroblasts confirm increased ISR activation due to the Ile465Serfs mutation and functional assays in yeast demonstrate that the Ile465Serfs mutation impairs eIF2γ function to a greater extent than tested missense mutations, consistent with the more severe clinical phenotype of the Ile465Serfs male mutation carriers. Thus, we propose that more severe EIF2S3 mutations cause the full MEHMO phenotype, while less deleterious mutations cause a milder form of the syndrome with only a subset of the symptoms.

The eukaryotic initiation factor 2 (eIF2) is a protein complex which is part of the cellular translation machinery. eIF2 comprises three subunits (α, β, γ), the γ subunit being the one which contains a GTP-binding domain and binding sites for the other two subunits α and β to interact. eIF2 acts in the initial part of the protein synthesis, forming a complex with GTP and Met-tRNAMeti. This ternary complex associates itself with the 40S subunit of the ribosome and, in a cap-dependent manner, scans the mRNA with the help of other factors. The recognition of the first AUG codon leads to the final assembly of the ribosome and the translation of the protein. Due to eIF2 importance, mutations in highly conserved regions of their genes might be lethal; however, a EIF2S3 mutation was recently found to be responsible for intellectual disability in male patients. In those patients, signs of problems in nervous system development are accompanied by a broad spectrum of other symptoms such as obesity, microgenitalism and ataxia gait, a syndrome known as MEHMO. This finding has motivated the present study in investigating why function disruption in a central player of protein translation mainly impacts on nervous system development. Patient-derived iPS cells were generated, and served as the model to learn more about eIF2, its impact on the cell proteome and its function in early neuronal development. The global translation profile from the iPSCs was obtained by SILAC-based LC-MSMS analysis, and the expression of candidate genes was assessed in a high-throughput manner at different time points of neuronal differentiation. A specific increase in APOE and CRABP1 (retinoic acid related proteins) translation and transcription was observed in patient cells, whereas CBS and TKT protein levels were decreased. Interestingly, other genes correlated to translation regulatory mechanisms were also differentially expressed. All this data indicates an imbalance of survival/apoptotic pathways activation due to translational impairment. Although the present results need further confirmation, this alteration on translation rates (iPSCs) suggests a very early embryonic development effect of the mutation. The findings on altered candidate proteins/mRNAs might open new avenues for future research. This hopefully will contribute to the understanding of both, the eIF2S3 roles so far not described and the exact functional consequences of the mutation.

Background: Eukaryotic translation initiation factor 2 subunit gamma (EIF2S3) is a component of eIF2 ,which functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA and binding to a 40S ribosomal subunit. The preliminary research suggested that in multiple malignant carcinomas, the expression level of EIF2S3 between the normal tissue and malignant one is Significantly different.It indicated that EIF2S3 might play an important role in the occurrence and development of malignant tumors .The purpose of this study is to investigate the expression status of EIF2S3 and its prognostic significance in AML patients. Methods:Total RNA was extracted from bone marrow of 42 patients. The expression of EIF2S3 was examined by Realtime quantitative PCR. The relationship of EIF2S3 expression and other clinicopathological charactors and itsprognosis significance were statistically analyzed. Results:The relative expression of EIF2S3 was much higher in patients who had achieved CR (median value 0.088, range: 0.0179-0.238;) compared with newly diagnosed AML patients(median value 0.037, range: 0.003-0.203),p value was 0.020.Furthermore, the expression of EIF2S3 was markedly associated with Complete Remission (P = 0.012) and outcome(P=0.029). Patients with lower EIF2S3 expression had a relatively poor overall survival(OS) (P = 0.016) and short disease-free survival(DFS) (P = 0.001). Moreover, EIF2S3 expression was an independent prognostic factor for both OS (P = 0.001) and DFS (P Conclusions:Patients who had achieved CR usually had a higher level of EIF2S3 expression compared with newly diagnosed AML patients. The over-expression of EIF2S3 is associated with good prognosis in AML patients, and was an independent prognostic factor for both OS and DFS. Disclosures No relevant conflicts of interest to declare.

Higher expression of X-linked genes in females might contribute to brain sexual differentiation. Although X-inactivation is thought to balance gene dosage between the two sexes, some X-linked genes escape X inactivation and therefore are expressed from both X chromosomes in females. Eif2s3x encodes subunit three of eukaryotic translation initiation factor 2, which regulates the rate of protein translation, and escapes X-inactivation in both humans and mice. By Northern blot analysis, we found Eif2s3x to be expressed higher in females than in males in developing and adult brains as well as adult liver. Gonadally intact XX mice had a higher level of Eif2s3x mRNA expression than XY mice regardless of whether they had testes or ovaries, suggesting that sexually dimorphic gene expression arises as a consequence of sex chromosome complement. In situ hybridization indicated that Eif2s3x mRNA was expressed preferentially in specific brain regions including the habenula, anterodorsal thalamic nucleus, hippocampus, hypothalamus, and cerebellum. Females had significantly higher levels of Eif2s3x mRNA expression than males in cortex, hippocampus and paraventricular nucleus but not in the habenula. The effect of a sex difference in Eif2s3x transcription, however, could potentially be offset by the additional expression in male brains of its Y-linked homologue Eif2s3y which was found in similar brain regions. The sex difference in Eif2s3x transcript appears not to be preserved at the protein level, since no difference in the levels of Eif2s3 protein was found between (1) males and females (2) XX and XY mice, or (3) XO and XX females.

International audience; Together with GTP and initiator methionyl-tRNA, translation initiation factor eIF2 forms a ternary complex that binds the 40S ribosome and then scans an mRNA to select the AUG start codon for protein synthesis. Here, we show that a human X-chromosomal neurological disorder characterized by intellectual disability and microcephaly is caused by a missense mutation in eIF2g (encoded by EIF2S3), the core subunit of the heterotrimeric eIF2 complex. Biochemical studies of human cells overexpressing the eIF2g mutant and of yeast eIF2g with the analogous mutation revealed a defect in binding the eIF2b subunit to eIF2g. Consistent with this loss of eIF2 integrity, the yeast eIF2g mutation impaired translation start codon selection and eIF2 function in vivo in a manner that was suppressed by overexpressing eIF2b. These findings directly link intellectual disability to impaired translation initiation, and provide a mechanistic basis for the human disease due to partial loss of eIF2 function.

Canis familiaris, the domestic dog, is a key animal species for preclinical drug development, including toxicity assessment. As data relating to gender dimorphic toxicity in the clinic emerge, the topic of sex differences in relation to drug toxicity will increase in prominence. Much of the emerging clinical data cannot easily be explained by body weight or body fat differences - hence the gender differences may be related to more complex hormonal and/or potential underlying gene expression differences. The dog also demonstrates some gender differences in drug-induced toxicity; hence, in the current study, we investigated differences at the gene expression level between male and female dogs in selected tissues of relevance to toxicity. We attempted to elucidate whether key gene expression differences do exist and if so, whether these gender differences may potentially impact on disease states, drug metabolism and toxicity. We investigated gene expression in the heart (the ventricle and atrium) along with the main tissues of drug absorption, metabolism and excretion, namely, the GI tract (ileum), liver and kidney (medulla and cortex) and performed in silico pathway analysis to elucidate key pathways possibly affected by gender dimorphic expression profi les. Surprisingly, we show that the post-transcriptional regulator, EIF2S3, is consistently highlighted across all six tissues examined: the gene was nearly three times over-expressed in male dogs compared to females, in all the tissues studied. This fi nding should be contrasted with the observation that the vast majority of genes showed no difference and for those where differences were found it was limited to one or two tissues. Thus, the discovery that EIF2S3 showed such large differences (common to all the tissues studied), was an intriguing fi nding. Pathway analysis showed tissue- specifi c gender dimorphic profi les are apparent between male and female canines; interestingly, EIF2S3 appeared to play a key role in these pathways. High homology with the human EIF2S3 raises the prospect of an analogous role for sex-differences in humans.