Ovarioleukodystrophy Due to EIF2B Genes: Systematic Review and Case Report.

Leukodystrophies comprise a spectrum of genetic disorders affecting white matter (WM) formation in the central nervous system (CNS), of which vanishing white matter disease (VWMD) is one. VWMD presents with progressive neurological deterioration and a variety of manifestations. Ovarioleukodystrophy, a subtype of VWMD, exhibits a distinctive clinical profile encompassing both CNS WM alterations and ovarian dysfunction. Variants in genes of the eukaryotic translation initiation factor 2B (EIF2B) complex affect the full form and are implicated in VWMD, including ovarioleukodystrophy. This work aimed to systematically review all published cases of ovarioleukodystrophy associated with variants in the EIF2B1-5 gene complex based on the first case identified in a Mexican population. We performed a systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines of published cases of ovarioleukodystrophy associated with the EIF2B gene complex, including a newly identified case from Mexico. We identified 207 publications using PUBMED, SCOPUS, and PMC databases. One hundred fifty-one publications were eliminated due to duplicates, titles, abstracts, or other reasons, while 56 publications were revised, of which 29 were eliminated because they dealt with other genes or non-human research, and 27 reports were assessed for eligibility. Finally, 14 reports describing ovarian involvement, neuroimaging, and molecular variants were included. Our review identified 20 cases worldwide, with a median age of onset of 19 years. Clinical features included WM involvement, ovarian abnormalities, gait disturbances, epilepsy, cognitive and language impairment, and other neurological manifestations. Neuroimaging showed characteristic WM changes, highlighting the importance of MRI in diagnosis. Missense variants predominated among the identified genetic mutations, especially in the EIF2B4 and EIF2B5 genes. Ovarioleukodystrophy is an ultra-rare disorder with a wide range of clinical manifestations and ovarian changes. Gynecological evaluation is crucial in suspected cases of ovarioleukodystrophy, as ovarian manifestations may precede neurological symptoms. The role of MRI is crucial in the diagnostic approach to this entity. Continued collaborative efforts are essential to elucidate genotype-phenotype correlations, improve clinical management, and promote therapeutic advances for this rare disorder.

Inhibition of mitophagy via the EIF2S1-ATF4-PRKN pathway contributes to viral encephalitis.

INTRODUCTION: Mitophagy, a selective form of autophagy responsible for maintaining mitochondrial homeostasis, regulates the antiviral immune response and acts as viral replication platforms to facilitate infection with various viruses. However, its precise role in herpes simplex virus 1 (HSV-1) infection and herpes simplex encephalitis (HSE) remains largely unknown. OBJECTIVES: We aimed to investigate the regulation of mitophagy by HSV-1 neurotropic infection and its role in viral encephalitis, and to identify small compounds that regulate mitophagy to affect HSV-1 infection. METHODS: The antiviral effects of compounds were investigated by Western blot, RT-PCR and plaque assay. The changes of Parkin (PRKN)-mediated mitophagy and Nuclear Factor kappa B (NFKB)-mediated neuroinflammation were examined by TEM, RT-qPCR, Western blot and ELISA. The therapeutic effect of taurine or PRKN-overexpression was confirmed in the HSE mouse model by evaluating survival rate, eye damage, neurodegenerative symptoms, immunohistochemistry analysis and histopathology. RESULTS: HSV-1 infection caused the accumulation of damaged mitochondria in neuronal cells and in the brain tissue of HSE mice. Early HSV-1 infection led to mitophagy activation, followed by inhibition in the later viral infection. The HSV-1 proteins ICP34.5 or US11 deregulated the EIF2S1-ATF4 axis to suppress PRKN/Parkin mRNA expression, thereby impeding PRKN-dependent mitophagy. Consequently, inhibition of mitophagy by specific inhibitor midiv-1 promoted HSV-1 infection, whereas mitophagy activation by PRKN overexpression or agonists (CCCP and rotenone) attenuated HSV-1 infection and reduced the NF-κB-mediated neuroinflammation. Moreover, PRKN-overexpressing mice showed enhanced resistance to HSV-1 infection and ameliorated HSE pathogenesis. Furthermore, taurine, a differentially regulated gut microbial metabolite upon HSV-1 infection, acted as a mitophagy activator that transcriptionally promotes PRKN expression to stimulate mitophagy and to limit HSV-1 infection both in vitro and in vivo. CONCLUSION: These results reveal the protective function of mitophagy in HSE pathogenesis and highlight mitophagy activation as a potential antiviral therapeutic strategy for HSV-1-related diseases.

Specificity of Key Sex Determination Genes in a Mammal with Ovotestes: The European Mole Talpa europaea.

Here, for the first time, the structure of genes involved in sex determination in mammals (full Sry and partial Rspo1, Eif2s3x, and Eif2s3y) was analyzed for the European mole Talpa europaea with ovotestes in females. We confirmed male-specificity for Eif2s3y and Sry. Five exons were revealed for Rspo1 and the deep similarity with the structure of this gene in T. occidentalis was proved. The most intriguing result was obtained for the Sry gene, which, in placental mammals, initiates male development. We described two exons for this canonically single-exon gene: the first (initial) exon is only 15 bp while the second exon includes 450 bp. The exons are divided by an extended intron of about 1894 bp, including the fragment of the LINE retroposon. Moreover, in chromatogram fragments, which correspond to intron and DNA areas, flanking both exons, we revealed double peaks, similar to heterozygous nucleotide sites of autosomal genes. This may indicate the existence of two or more copies of the Sry gene. Proof of copies requires an additional in-depth study. We hypothesize that unusual structure and possible supernumerary copies of Sry may be involved in ovotestes formation.

Gcn2 structurally mimics and functionally repurposes the HisRS enzyme for the integrated stress response.

Protein kinase Gcn2 attenuates protein synthesis in response to amino acid starvation while stimulating translation of a transcriptional activator of amino acid biosynthesis. Gcn2 activation requires a domain related to histidyl-tRNA synthetase (HisRS), the enzyme that aminoacylates tRNAHis. While evidence suggests that deacylated tRNA binds the HisRS domain for kinase activation, ribosomal P-stalk proteins have been implicated as alternative activating ligands on stalled ribosomes. We report crystal structures of the HisRS domain of Chaetomium thermophilum Gcn2 that reveal structural mimicry of both catalytic (CD) and anticodon-binding (ABD) domains, which in authentic HisRS bind the acceptor stem and anticodon loop of tRNAHis. Elements for forming histidyl adenylate and aminoacylation are lacking, suggesting that Gcn2HisRS was repurposed for kinase activation, consistent with mutations in the CD that dysregulate yeast Gcn2 function. Substituting conserved ABD residues well positioned to contact the anticodon loop or that form a conserved ABD-CD interface impairs Gcn2 function in starved cells. Mimicry in Gcn2HisRS of two highly conserved structural domains for binding both ends of tRNA-each crucial for Gcn2 function-supports that deacylated tRNAs activate Gcn2 and exemplifies how a metabolic enzyme is repurposed to host new local structures and sequences that confer a novel regulatory function.

Activation of the PERK/eIF2α axis is a pivotal prerequisite of taxanes to cancer cell apoptosis and renders synergism to overcome paclitaxel resistance in breast cancer cells.

BACKGROUND: Microtubule polymerization is usually considered as the upstream of apoptotic cell death induced by taxanes, but recently published studies provide more insights into the mechanisms responsible for the antineoplastic effect of taxanes. In this study, we figure out the role of the stress-related PERK/eIF2α axis in tumor cell death upon taxane treatment along with paclitaxel resistance. METHODS: Utilizing immunoblot assay, the activation status of PERK-eIF2α signaling was detected in a panel of cancer cell lines after the treatment of taxanes. The causal role of PERK-eIF2α signaling in the cancer cell apoptosis induced by taxanes was examined via pharmacological and genetic inhibitions of PERK. The relationship between microtubule polymerization and PERK-eIF2α activation was explored by immunofluorescent and immunoblotting assays. Eventaually, the combined therapeutic effect of paclitaxel (PTX) and CCT020312, a PERK agonist, was investigated in PTX-resistant breast cancer cells in vitro and in vivo. RESULTS: PERK-eIF2α axis was dramatically activated by taxanes in several cancer cell types. Pharmacological or genetic inhibition of PERK efficiently impaired taxane-induced apoptotic cell death, independent of the cellular microtubule polymerization status. Moreover, PTX was able to activate the PERK/eIF2α axis in a very low concentration without triggering microtubule polymerization. In PTX-resistant breast cancer cells, the PERK/eIF2α axis was attenuated in comparison with the PTX-sensitive counterparts. Reactivation of the PERK/eIF2α axis in the PTX-resistant breast cancer cells with PERK agonist sensitized them to PTX in vitro. Combination treatment of the xenografted PTX-resistant breast tumors with PERK agonist and PTX validated the synergic effect of PTX and PERK activation in vivo. CONCLUSION: Activation of the PERK/eIF2α axis is a pivotal prerequisite of taxanes to initiate cancer cell apoptosis, which is independent of the well-known microtubule polymerization-dependent manner. Simultaneous activation of PERK-eIF2α signaling would be a promising therapeutic strategy to overcome PTX resistance in breast cancer or other cancers.

TXNDC5 Plays a Crucial Role in Regulating Endoplasmic Reticulum Activity through Different ER Stress Signaling Pathways in Hepatic Cells.

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) is influenced by a number of variables, including endoplasmic reticulum stress (ER). Thioredoxin domain-containing 5 (TXNDC5) is a member of the protein disulfide isomerase family and acts as an endoplasmic reticulum (ER) chaperone. Nevertheless, the function of TXNDC5 in hepatocytes under ER stress remains largely uncharacterized. In order to identify the role of TXNDC5 in hepatic wild-type (WT) and TXNDC5-deficient (KO) AML12 cell lines, tunicamycin, palmitic acid, and thapsigargin were employed as stressors. Cell viability, mRNA, protein levels, and mRNA splicing were then assayed. The protein expression results of prominent ER stress markers indicated that the ERN1 and EIF2AK3 proteins were downregulated, while the HSPA5 protein was upregulated. Furthermore, the ATF6 protein demonstrated no significant alterations in the absence of TXNDC5 at the protein level. The knockout of TXNDC5 has been demonstrated to increase cellular ROS production and its activity is required to maintain normal mitochondrial function during tunicamycin-induced ER stress. Tunicamycin has been observed to disrupt the protein levels of HSPA5, ERN1, and EIF2AK3 in TXNDC5-deficient cells. However, palmitic acid has been observed to disrupt the protein levels of ATF6, HSPA5, and EIF2AK3. In conclusion, TXNDC5 can selectively activate distinct ER stress pathways via HSPA5, contingent on the origin of ER stress. Conversely, the absence of TXNDC5 can disrupt the EIF2AK3 cascade.

EIF2S2 transcriptionally upregulates HIF1α to promote gastric cancer progression via activating PI3K/AKT/mTOR pathway.

Eukaryotic translation initiation factor 2 subunit beta (EIF2S2) is a protein that controls protein synthesis under various stress conditions and is abnormally expressed in several cancers. However, there is limited insight regarding the expression and molecular role of EIF2S2 in gastric cancer. In this study, we identified the overexpression of EIF2S2 in gastric cancer by immunohistochemical (IHC) staining and found a positive correlation between EIF2S2 expression and shorter overall survival and disease-free survival. Functionally, we revealed that EIF2S2 knockdown suppressed gastric cancer cell proliferation and migration, induced cell apoptosis, and caused G2 phase cell arrest. Additionally, EIF2S2 is essential for in vivo tumor formation. Mechanistically, we demonstrated that EIF2S2 transcriptionally regulated hypoxia induicible factor-1 alpha (HIF1α) expression by NRF1. The promoting role of EIF2S2 in malignant behaviors of gastric cancer cells depended on HIF1α expression. Furthermore, the PI3K/AKT/mTOR signaling was activated upon EIF2S2 overexpression in gastric cancer. Collectively, EIF2S2 exacerbates gastric cancer progression via targeting HIF1α, providing a fundamental basis for considering EIF2S2 as a potential therapeutic target for gastric cancer patients.

Sex-specific effect of antenatal Zika virus infection on murine fetal growth, placental nutrient transporters, and nutrient sensor signaling pathways.

Maternal Zika virus (ZIKV) infection during pregnancy has been associated with severe intrauterine growth restriction (IUGR), placental damage, metabolism disturbances, and newborn neurological abnormalities. Here, we investigated the impact of maternal ZIKV infection on placental nutrient transporters and nutrient-sensitive pathways. Immunocompetent (C57BL/6) mice were injected with Low (103 PFU-ZIKVPE243) or High (5 × 107 PFU-ZIKVPE243) ZIKV titers at gestational day (GD) 12.5, and tissue was collected at GD18.5 (term). Fetal-placental growth was impaired in male fetuses, which exhibited higher placental expression of the ZIKV infective marker, eukaryotic translation initiation factor 2 (eIF2α), but lower levels of phospho-eIF2α. There were no differences in fetal-placental growth in female fetuses, which exhibited no significant alterations in placental ZIKV infective markers. Furthermore, ZIKV promoted increased expression of glucose transporter type 1 (Slc2a1/Glut1) and decreased levels of glucose-6-phosphate in female placentae, with no differences in amino acid transport potential. In contrast, ZIKV did not impact glucose transporters in male placentae but downregulated sodium-coupled neutral amino acid 2 (Snat2) transporter expression. We also observed sex-dependent differences in the hexosamine biosynthesis pathway (HBP) and O-GlcNAcylation in ZIKV-infected pregnancies, showing that ZIKV can disturb placental nutrient sensing. Our findings highlight molecular alterations in the placenta caused by maternal ZIKV infection, shedding light on nutrient transport, sensing, and availability. Our results also suggest that female and male placentae employ distinct coping mechanisms in response to ZIKV-induced metabolic changes, providing insights into therapeutic approaches for congenital Zika syndrome.

Tetrahydrocurcumin Attenuates Polymyxin B Sulfate-Induced HK-2 Cells Apoptosis by Inhibiting Endoplasmic Reticulum Stress-Mediated PERK/eIF2α/ATF4/CHOP Signaling Pathway Axis.

The clinical application of polymyxin B (PMB) is limited by its nephrotoxic effects, making the reduction of PMB-induced nephrotoxicity has become a pressing concern for clinicians. Tetrahydrocurcumin (THC), known for its beneficial characteristics in biological functions, presents an attractive option for intervention therapy to mitigate PMB-induced nephrotoxicity. However, the underlying mechanism of how THC mitigates PMB-induced nephrotoxicity is still poorly understood. Here, we first evaluated the potential of THC intervention therapy to mitigate PMB-induced nephrotoxicity in an in vitro model of PMB-induced cell injury. Moreover, we demonstrated that THC effectively protected HK-2 cells from PMB-induced apoptosis by using cell counting kit-8 and flow cytometry assay. THC could also suppress PMB-induced endoplasmic reticulum (ER) stress via PERK/eIF2α/ATF4/CHOP pathway. In addition, using PERK inhibitor GSK2606414 to inhibit ER stress also alleviated PMB-induced apoptosis. Taken together, these findings provide novel insights that THC possesses the ability to alleviate PMB-induced nephrotoxicity by inhibiting the ER stress-mediated PERK/eIF2α/ATF4/CHOP axis, which sheds light on the benefits of THC as an intervention strategy to reduce PMB-induced nephrotoxicity, thus providing a potential avenue for improved clinical outcomes in patients receiving PMB treatment.

Neurodevelopmental disorder-associated CYFIP2 regulates membraneless organelles and eIF2α phosphorylation via protein interactors and actin cytoskeleton.

De novo variants in the Cytoplasmic FMR1-interacting protein 2 (CYFIP2) have been repeatedly associated with neurodevelopmental disorders and epilepsy, underscoring its critical role in brain development and function. While CYFIP2's role in regulating actin polymerization as part of the WAVE regulatory complex (WRC) is well-established, its additional molecular functions remain relatively unexplored. In this study, we performed unbiased quantitative proteomic analysis, revealing 278 differentially expressed proteins (DEPs) in the forebrain of Cyfip2 knock-out embryonic mice compared to wild-type mice. Unexpectedly, these DEPs, in conjunction with previously identified CYFIP2 brain interactors, included not only other WRC components but also numerous proteins associated with membraneless organelles (MLOs) involved in mRNA processing and translation within cells, including the nucleolus, stress granules, and processing bodies. Additionally, single-cell transcriptomic analysis of the Cyfip2 knock-out forebrain revealed gene expression changes linked to cellular stress responses and MLOs. We also observed morphological changes in MLOs in Cyfip2 knock-out brains and CYFIP2 knock-down cells under basal and stress conditions. Lastly, we demonstrated that CYFIP2 knock-down in cells, potentially through WRC-dependent actin regulation, suppressed the phosphorylation levels of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α), thereby enhancing protein synthesis. These results suggest a physical and functional connection between CYFIP2 and various MLO proteins and also extend CYFIP2's role within the WRC from actin regulation to influencing eIF2α phosphorylation and protein synthesis. With these dual functions, CYFIP2 may fine-tune the balance between MLO formation/dynamics and protein synthesis, a crucial aspect of proper mRNA processing and translation.

Melatonin Protects Against Mitochondrial Dyshomeostasis and Ovarian Damage Caused by Chronic Unpredictable Mild Stress Through the eIF2α-AFT4 Signaling Pathway in Mice.

Stress is an emotional state caused by an unexpected external environmental change or stimulus, and several experiments have demonstrated its negative impact on ovarian function, ultimately affecting reproductive ability. Melatonin (MT) has been shown to facilitate oocyte maturation and enhance ovarian function by regulating mitochondrial function. However, the specific effect and underlying molecular mechanisms of MT on stress-induced ovarian dysfunction remain largely unknown. In this study, we established a mouse model of chronic unpredictable mild stress (CUMS) to investigate its impact on ovarian function. Our findings revealed that CUMS led to premature ovarian insufficiency (POI) in mice, characterized by a reduction in follicle numbers and decreased levels of anti-Müllerian hormone (AMH) and bone morphogenetic protein 15 (BMP15). Furthermore, CUMS caused decreased expression of mitochondrial fission protein 1 (FIS1) and enhanced level of mitochondrial fusion protein optic atrophy 1(OPA1), mitofusin1(MFN1), as well as nucleus-encoded protein succinate dehydrogenase complex A (SDHA), reflecting mitochondrial dyshomeostasis. Additionally, CUMS resulted in excessive autophagy and apoptosis. However, MT reversed these effects and improved ovarian damage. Importantly, the protective effects of MT were mediated through the inhibition of the eIF2α-AFT4 pathway. Overall, this study provides valuable insights into the treatment of POI caused by CUMS.

Polystyrene microplastics trigger testosterone decline via GPX1.

As an emerging environmental endocrine disruptor, polystyrene microplastics (PS-MPs) are considered to have the anti-androgenic feature and impair male reproductive function. To explore the adverse effects of PS-MPs on testosterone synthesis and male reproduction and further elucidate underlying mechanisms, BALB/c mice and Leydig cells were employed in the present work. The results indicated that 50 µm PS-MPs accumulated in mouse testes and were internalized into the cytoplasm. This not only damaged the testicular histomorphology and ultrastructure, but also reduced the viability of Leydig cells and the serum level of GnRH, FSH, LH, and testosterone. After PS-MPs exposure, the ubiquitination degradation and miR-425-3p-targeted modulation synergistically contributed to the suppression of GPX1, which induced oxidative stress and subsequently activated the PERK-EIF2α-ATF4-CHOP pathway of endoplasmic reticulum (ER) stress. The transcription factor CHOP positively regulated the expression of SRD5A2 by directly binding to its promoter region, thereby accelerating testosterone metabolism and ultimately lowing testosterone levels. Besides, PS-MPs compromised testosterone homeostasis via interfering with the hypothalamic-pituitary-testis (HPT) axis. Taken together, PS-MPs possess an anti-androgenic characteristic and exert male reproductive damage effects. The antioxidant enzyme GPX1 plays a crucial role in the PS-MPs-mediated testosterone decline.

Induction of the PERK-eIF2α-ATF4 Pathway in M1 Macrophages under Endoplasmic Reticulum Stress.

Translation inhibition can activate two cell death pathways. The first pathway is activated by translational aberrations, the second by endoplasmic reticulum (ER) stress. In this work, the effect of ribosome-inactivating protein type II (RIP-II) viscumin on M1 macrophages derived from the THP-1 cell line was investigated. The number of modified ribosomes was evaluated by real-time PCR. Transcriptome analysis revealed that viscumin induces the ER stress activated by the PERK sensor.

Impacts of yeast Tma20/MCTS1, Tma22/DENR and Tma64/eIF2D on translation reinitiation and ribosome recycling.

Recycling of 40S ribosomal subunits following translation termination, entailing release of deacylated tRNA and dissociation of the empty 40S subunit from mRNA, involves yeast Tma20/Tma22 heterodimer and Tma64, counterparts of mammalian MCTS1/DENR and eIF2D. MCTS1/DENR enhance reinitiation at short upstream open reading frames (uORFs) harboring penultimate codons that confer dependence on these factors in bulk 40S recycling. Tma factors, by contrast, inhibited reinitiation at particular uORFs in extracts; however, their roles at regulatory uORFs in vivo were unknown. We examined effects of eliminating Tma proteins on reinitiation at regulatory uORFs mediating translational control of GCN4 optimized for either promoting (uORF1) or preventing (uORF4) reinitiation. We found that the Tma proteins generally impede reinitiation at native uORF4 and uORF4 variants equipped with various penultimate codons regardless of their Tma-dependence in bulk recycling. The Tma factors have no effect on reinitiation at native uORF1, and equipping uORF1 with Tma-dependent penultimate codons generally did not confer Tma-dependent reinitiation; nor did converting the uORFs to AUG-stop elements. Thus, effects of the Tma proteins vary depending on the reinitiation potential of the uORF and the penultimate codon, but unlike in mammals, are not principally dictated by the Tma-dependence of the codon in bulk 40S recycling.

Translocational attenuation mediated by the PERK-SRP14 axis is a protective mechanism of unfolded protein response.

The unfolded protein response (UPR) relieves endoplasmic reticulum (ER) stress through multiple strategies, including reducing protein synthesis, increasing protein folding capabilities, and enhancing misfolded protein degradation. After a multi-omics analysis, we find that signal recognition particle 14 (SRP14), an essential component of the SRP, is markedly reduced in cells undergoing ER stress. Further experiments indicate that SRP14 reduction requires PRKR-like ER kinase (PERK)-mediated eukaryotic translation initiation factor 2α (eIF2α) phosphorylation but is independent of ATF4 or ATF3 transcription factors. The decrease of SRP14 correlates with reduced translocation of fusion proteins and endogenous cathepsin D. Enforced expression of an SRP14 variant with elongation arrest capability prevents the reduced translocation of cathepsin D in stressed cells, whereas an SRP14 mutant without the activity does not. Finally, overexpression of SRP14 augments the UPR and aggravates ER-stress-induced cell death. These data suggest that translocational attenuation mediated by the PERK-SRP14 axis is a protective measure for the UPR to mitigate ER stress.

eIF2ß zinc-binding domain interacts with the eIF2γ subunit through the guanine nucleotide binding interface to promote Met-tRNAiMet binding.

The heterotrimeric eIF2 complex consists of a core eIF2γ subunit to which binds eIF2α and eIF2ß subunits and plays an important role in delivering the Met-tRNAiMet to the 40S ribosome and start codon selection. The intricacies of eIF2ß-γ interaction in promoting Met-tRNAiMet binding are not clearly understood. Previously, the zinc-binding domain (ZBD) eIF2ßS264Y mutation was reported to cause Met-tRNAiMet binding defect due to the intrinsic GTPase activity. We showed that the eIF2ßS264Y mutation has eIF2ß-γ interaction defect. Consistently, the eIF2ßT238A intragenic suppressor mutation restored the eIF2ß-γ and Met-tRNAiMet binding. The eIF2ß-ZBD residues Asn252Asp and Arg253Ala mutation caused Met-tRNAiMet binding defect that was partially rescued by the eIF2ßT238A mutation, suggesting the eIF2ß-ZBD modulates Met-tRNAiMet binding. The suppressor mutation rescued the translation initiation fidelity defect of the eIF2γN135D SW-I mutation and eIF2ßF217A/Q221A double mutation in the HTH domain. The eIF2ßT238A suppressor mutation could not rescue the eIF2ß binding defect of the eIF2γV281K mutation; however, combining the eIF2ßS264Y mutation with the eIF2γV281K mutation was lethal. In addition to the previously known interaction of eIF2ß with the eIF2γ subunit via its α1-helix, the eIF2ß-ZBD also interacts with the eIF2γ subunit via guanine nucleotide-binding interface; thus, the eIF2ß-γ interacts via two distinct binding sites.

Knockdown of EIF2AK2-OAS1 axis reduces ATP production inducing AMPK phosphorylation to inhibit the malignant behavior of gastric cancer cells.

Energy metabolism has always been a hot topic in cancer progression and targeted therapy, and exploring the role of genes in energy metabolic pathways in cancer cells has become key to address this issue. Eukaryotic translation initiation factor 2α kinase 2 (EIF2AK2) plays regulatory roles in cancer and disorders of energy metabolism. Indeed, the role of EIF2AK2 in energy metabolism has been underestimated. The aim of this study is to reveal the expression specificity of EIF2AK2 in gastric cancer (GC) progression and metastasis, and to demonstrate the role of EIF2AK2 in energy metabolism, cytoskeleton, proliferation, death and metastasis pathways in GC cells. Mechanistically, EIF2AK2 overexpression promoted cytoskeleton remodeling and ATP production, mediated cell proliferation and metastasis, upregulated OAS1 expression, decreases p-AMPK expression and inhibited apoptosis in GC cells. Conversely, knockdown of EIF2AK2 resulted in the opposite effect. However, overexpression of OAS1 mediated the upregulation of mitochondrial membrane potential and promoted ATP production and NAD+/NADH ratio, but knockdown of OAS1 inhibited the above effects. In addition, knockdown of OAS1 had no effect on EIF2AK2 expression, but inhibited AMPK and upregulated p-AMPK expression. In conclusion, our study identified EIF2AK2 and OAS1 as previously undescribed regulators of energy metabolism in GC cells. We hypothesized that EIF2AK2-OAS1 axis may regulate energy metabolism and inhibit cellular malignant behavior in cancer cells by affecting ATP production to induce AMPK phosphorylation, suggesting EIF2AK2 as a potential therapeutic target for cancer cell progression.

Vanishing white matter disease: imaging, clinical and molecular correlation in Brazilian families.

PURPOSE: To characterize Vanishing White Matter Disease (VWM) cases from a Brazilian University Tertiary hospital, focusing on brain magnetic resonance image (MRI) aspects, clinical and molecular data. METHODS: Medical records and brain MRI of 13 genetically confirmed VWM patients were reviewed. Epidemiological data such as age at symptom onset, gender and main symptoms were analyzed, along with genetic mutations and MRI characteristics, such as the distribution of white matter lesions and atrophy. RESULTS: The majority of patients were female, with the age of symptom onset ranging from 1 year and 6 months to 40 years. All mutations were identified in the EIF2B5 gene, the most prevalent being c.338G > A (p.Arg113His), and a novel mutation related to the disease was discovered, c.1051G > A (p.Gly351Ser). Trauma or infection were significant triggers. The most frequent symptoms were ataxia and limb spasticity. All MRI scans displayed deep white matter involvement, cystic degeneration, with U-fibers relatively spared and a predilection for the frontoparietal region. Lesions in the corpus callosum and posterior fossa were present in all patients. Follow-up exams revealed the evolution of white matter lesions and cerebral atrophy, which correlated with clinical deterioration. CONCLUSIONS: VWM affects various age groups, with a significant clinical and genetic variability. A novel mutation associated with the disease is highlighted. MRI reveals a typical pattern of white matter involvement, characterized by diffuse lesions in the periventricular and deep regions, with subsequent extension to the subcortical areas, accompanied by cystic degeneration, and plays a crucial role in diagnosis and follow-up.

Niacin, an innovative protein kinase-C-dependent endoplasmic reticulum stress reticence in murine Parkinson's disease.

AIMS: Niacin (NIA) supplementation showed effectiveness against Parkinson's disease (PD) in clinical trials. The depletion of NAD and endoplasmic reticulum stress response (ERSR) are implicated in the pathogenesis of PD, but the potential role for NAD precursors on ERSR is not yet established. This study was undertaken to decipher NIA molecular mechanisms against PD-accompanied ERSR, especially in relation to PKC. METHODS: Alternate-day-low-dose-21 day-subcutaneous exposure to rotenone (ROT) in rats induced PD. Following the 5th ROT injection, rats received daily doses of either NIA alone or preceded by the PKC inhibitor tamoxifen (TAM). Extent of disease progression was assessed by behavioral, striatal biochemical and striatal/nigral histopathological/immunohistochemical analysis. KEY FINDINGS: Via activating PKC/LKB1/AMPK stream, NIA post-treatment attenuated the ERSR reflected by the decline in ATF4, ATF6 and XBP1s to downregulate the apoptotic markers, CHOP/GADD153, p-JNK and active caspase-3. Such amendments congregated in motor activity/coordination improvements in open field and rotarod tasks, enhanced grid test latency and reduced overall PD scores, while boosting nigral/striatal tyrosine hydroxylase immunoreactivity and increasing intact neurons (Nissl stain) in both SNpc and striatum that showed less neurodegeneration (H&E stain). To different extents, TAM reverted all the NIA-related actions to prove PKC as a fulcrum in conveying the drug neurotherapeutic potential. SIGNIFICANCE: PKC activation is a pioneer mechanism in the drug ERSR inhibitory anti-apoptotic modality to clarify NIA promising clinical and potent preclinical anti-PD efficacy. This kinase can be tagged as a druggable target for future add-on treatments that can assist dopaminergic neuronal aptitude against this devastating neurodegenerative disease.

Pifithrin-µ Induces Stress Granule Formation, Regulates Cell Survival, and Rewires Cellular Signaling.

(1) Background: Stress granules (SGs) are cytoplasmic protein-RNA condensates that assemble in response to various insults. SG production is driven by signaling pathways that are relevant to human disease. Compounds that modulate SG characteristics are therefore of clinical interest. Pifithrin-µ is a candidate anti-tumor agent that inhibits members of the hsp70 chaperone family. While hsp70s are required for granulostasis, the impact of pifithrin-µ on SG formation is unknown. (2) Methods: Using HeLa cells as model system, cell-based assays evaluated the effects of pifithrin-µ on cell viability. Quantitative Western blotting assessed cell signaling events and SG proteins. Confocal microscopy combined with quantitative image analyses examined multiple SG parameters. (3) Results: Pifithrin-µ induced bona fide SGs in the absence of exogenous stress. These SGs were dynamic; their properties were determined by the duration of pifithrin-µ treatment. The phosphorylation of eIF2α was mandatory to generate SGs upon pifithrin-µ exposure. Moreover, the formation of pifithrin-µ SGs was accompanied by profound changes in cell signaling. Pifithrin-µ reduced the activation of 5'-AMP-activated protein kinase, whereas the pro-survival protein kinase Akt was activated. Long-term pifithrin-µ treatment caused a marked loss of cell viability. (4) Conclusions: Our study identified stress-related changes in cellular homeostasis that are elicited by pifithrin-µ. These insights are important knowledge for the appropriate therapeutic use of pifithrin-µ and related compounds.