Overlapping peri-implantation phenotypes of ZNHIT1 and ZNHIT2 despite distinct functions during early mouse development.

Mammalian preimplantation development culminates in the formation of a blastocyst which undergoes extensive gene expression regulation to successfully implant into the maternal endometrium. Zinc-finger HIT domain-containing (ZNHIT) 1 and 2 are members of a highly conserved family, yet they have been identified as subunits of distinct complexes. Here we report that knockout of either Znhit1 or Znhit2 results in embryonic lethality during peri-implantation stages. Znhit1 and Znhit2 mutant embryos have overlapping phenotypes, including reduced proportion of SOX2-positive ICM cells, a lack of Fgf4 expression and aberrant expression of NANOG and SOX17. Furthermore, we find that the similar phenotypes are caused by distinct mechanisms. Specifically, embryos lacking ZNHIT1 likely fail to incorporate sufficient H2A.Z at the promoter region of Fgf4 and other genes involved in cell projection organization resulting in impaired invasion of trophoblast cells during implantation. In contrast, Znhit2 mutant embryos display a complete lack of nuclear EFTUD2, a key component of U5 spliceosome, indicating a global splicing deficiency. Our findings unveil the indispensable yet distinct roles of ZNHIT1 and ZNHIT2 in early mammalian embryonic development.

Spliceosomal GTPase Eftud2 deficiency-triggered ferroptosis leads to Purkinje cell degeneration.

Spliceosomal GTPase elongation factor Tu GTP binding domain containing 2 (EFTUD2) is a causative gene for mandibulofacial dysostosis with microcephaly (MFDM) syndrome comprising cerebellar hypoplasia and motor dysfunction. How EFTUD2 deficiency contributes to these symptoms remains elusive. Here, we demonstrate that specific ablation of Eftud2 in cerebellar Purkinje cells (PCs) in mice results in severe ferroptosis, PC degeneration, dyskinesia, and cerebellar atrophy, which recapitulates phenotypes observed in patients with MFDM. Mechanistically, Eftud2 promotes Scd1 and Gch1 expression, upregulates monounsaturated fatty acid phospholipids, and enhances antioxidant activity, thereby suppressing PC ferroptosis. Importantly, we identified transcription factor Atf4 as a downstream target to regulate anti-ferroptosis effects in PCs in a p53-independent manner. Inhibiting ferroptosis efficiently rescued cerebellar deficits in Eftud2 cKO mice. Our data reveal an important role of Eftud2 in maintaining PC survival, showing that pharmacologically or genetically inhibiting ferroptosis may be a promising therapeutic strategy for EFTUD2 deficiency-induced disorders.

[Inhibitory effect of small-molecule compound AM679 targeting elongation-factor binding protein 2 on hepatitis B virus in vitro].

Objective: To explore the antiviral activity of the small-molecule compound AM679 in hepatitis B virus (HBV) replication and infection cell models. Methods: The positive regulatory effect of AM679 on EFTUD2 expression was validated by qPCR and Western blotting. HepAD38 and HepG2-NTCP cells were treated with AM679 (0.5, 1, and 2 nmol/L). Negative control, positive control, and AM679 combined with the entecavir group were set up. HBV DNA intra-and extracellularly, as well as the expression levels of intracellular HBV total RNAs and 3.5kb-RNA changes, were detected with qPCR. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels were measured in the cell supernatant by an enzyme-linked immunosorbent assay (ELISA). The t-test method was used for the statistical analysis of the mean difference between groups. Results: EFTUD2 mRNA and protein expression levels were significantly increased in HepAD38 and HepG2-NTCP cells following AM679 treatment, with a statistically significant difference (P < 0.001). Intra-and extracellular indicators such as HBV DNA, HBV RNAs, HBV 3.5kb-RNA, HBsAg, and HBeAg were decreased to varying degrees in both cell models, and the decrease in these indicators was more pronounced with the increase in AM679 concentration and prolonged treatment duration, while the combined use of AM679 and entecavir had a more significant antiviral effect. The HBV DNA inhibition rates in the supernatant of HepAD38 cells with the use of 2 nmol/L AM679 were 21% and 48% on days three and nine, respectively. The AM679 combined with the ETV treatment group had the most significant inhibitory effect (62%), with a P < 0.01. More active HBV replication was observed after silencing EFTUD2, while the antiviral activity of AM679 was significantly weakened. Conclusion: AM679 exerts anti-HBV activity in vitro by targeting the regulation of EFTUD2 expression.

Atypical mandibulofacial dysostosis with microcephaly diagnosed through the identification of a novel pathogenic mutation in EFTUD2.

BACKGROUND: Mandibulofacial dysostosis with microcephaly (MFDM, OMIM# 610536) is a rare monogenic disease that is caused by a mutation in the elongation factor Tu GTP binding domain containing 2 gene (EFTUD2, OMIM* 603892). It is characterized by mandibulofacial dysplasia, microcephaly, malformed ears, cleft palate, growth and intellectual disability. MFDM can be easily misdiagnosed due to its phenotypic overlap with other craniofacial dysostosis syndromes. The clinical presentation of MFDM is highly variable among patients. METHODS: A patient with craniofacial anomalies was enrolled and evaluated by a multidisciplinary team. To make a definitive diagnosis, whole-exome sequencing was performed, followed by validation by Sanger sequencing. RESULTS: The patient presented with extensive facial bone dysostosis, upward slanting palpebral fissures, outer and middle ear malformation, a previously unreported orbit anomaly, and spina bifida occulta. A novel, pathogenic insertion mutation (c.215_216insT: p.Tyr73Valfs*4) in EFTUD2 was identified as the likely cause of the disease. CONCLUSIONS: We diagnosed this atypical case of MFDM by the detection of a novel pathogenetic mutation in EFTUD2. We also observed previously unreported features. These findings enrich both the genotypic and phenotypic spectrum of MFDM.

Prenatal Diagnosis of Fetal Micrognathia at 11-20 Weeks of Gestation: A Prospective Observation Study.

OBJECTIVE: To prospectively evaluate the prognosis of fetuses diagnosed with micrognathia using prenatal ultrasound screening. METHODS: Between January 2019 and December 2022, a normal range of IFA to evaluate the facial profile in fetuses with micrognathia in a Chinese population between 11 and 20 gestational weeks was established, and the pregnancy outcomes of fetal micrognathia were described. The medical records of these pregnancies were collected, including family history, maternal demographics, sonographic findings, genetic testing results, and pregnancy outcomes. RESULTS: Ultrasound identified 25 patients with fetal micrognathia, with a mean IFA value of 43.6°. All cases of isolated fetal micrognathia in the initial scans were non-isolated in the following scans. A total of 78.9% (15/19) cases had a genetic cause confirmed, including 12 with chromosomal abnormalities and 3 with monogenic disorders. Monogenic disorders were all known causes of micrognathia, including two cases of campomelic dysplasia affected by SOX9 mutations and one case of mandibulofacial dysostosis with an EFTUD2 mutation. In the end, 19 cases were terminated, 1 live birth was diagnosed as Pierre Robin syndrome, and 5 cases were lost to follow-up. CONCLUSION: IFA is a useful indicator and three-dimensional ultrasound is a significant support technique for fetal micrognathia prenatal diagnosis. Repeat ultrasound monitoring and genetic testing are crucial, with CMA recommended and Whole exome sequencing performed when normal arrays are reported. Isolated fetal micrognathia may be an early manifestation of monogenic disorders.

The feedback loop of EFTUD2/c-MYC impedes chemotherapeutic efficacy by enhancing EFTUD2 transcription and stabilizing c-MYC protein in colorectal cancer.

BACKGROUND: Chemoresistance presents a significant obstacle in the treatment of colorectal cancer (CRC), yet the molecular basis underlying CRC chemoresistance remains poorly understood, impeding the development of new therapeutic interventions. Elongation factor Tu GTP binding domain containing 2 (EFTUD2) has emerged as a potential oncogenic factor implicated in various cancer types, where it fosters tumor growth and survival. However, its specific role in modulating the sensitivity of CRC cells to chemotherapy is still unclear. METHODS: Public dataset analysis and in-house sample validation were conducted to assess the expression of EFTUD2 in 5-fluorouracil (5-FU) chemotherapy-resistant CRC cells and the potential of EFTUD2 as a prognostic indicator for CRC. Experiments both in vitro, including MTT assay, EdU cell proliferation assay, TUNEL assay, and clone formation assay and in vivo, using cell-derived xenograft models, were performed to elucidate the function of EFTUD2 in sensitivity of CRC cells to 5-FU treatment. The molecular mechanism on the reciprocal regulation between EFTUD2 and the oncogenic transcription factor c-MYC was investigated through molecular docking, ubiquitination assay, chromatin immunoprecipitation (ChIP), dual luciferase reporter assay, and co-immunoprecipitation (Co-IP). RESULTS: We found that EFTUD2 expression was positively correlated with 5-FU resistance, higher pathological grade, and poor prognosis in CRC patients. We also demonstrated both in vitro and in vivo that knockdown of EFTUD2 sensitized CRC cells to 5-FU treatment, whereas overexpression of EFTUD2 impaired such sensitivity. Mechanistically, we uncovered that EFTUD2 physically interacted with and stabilized c-MYC protein by preventing its ubiquitin-mediated proteasomal degradation. Intriguingly, we found that c-MYC directly bound to the promoter region of EFTUD2 gene, activating its transcription. Leveraging rescue experiments, we further confirmed that the effect of EFTUD2 on 5-FU resistance was dependent on c-MYC stabilization. CONCLUSION: Our findings revealed a positive feedback loop involving an EFTUD2/c-MYC axis that hampers the efficacy of 5-FU chemotherapy in CRC cells by increasing EFTUD2 transcription and stabilizing c-MYC oncoprotein. This study highlights the potential of EFTUD2 as a promising therapeutic target to surmount chemotherapy resistance in CRC patients.

Plerixafor and resatorvid inhibit hepatitis B virus in vitro by upregulating elongation factor Tu GTP-binding domain containing 2.

Background: An increase in the demand for a functional cure has accelerated research on new methods of therapy for chronic hepatitis B, which is mainly focused on restoring antiviral immunity for controlling viral infections. Previously, we had described elongation factor Tu GTP-binding domain containing 2 (EFTUD2) as an innate immune regulator and suggested that it might be an antiviral target. Methods: In this study, we generated the Epro-LUC-HepG2 cell model for screening compounds that target EFTUD2. Plerixafor and resatorvid were screened from 261 immunity and inflammation-related compounds due to their ability to highly upregulate EFTUD2. The effects of plerixafor and resatorvid on hepatitis B virus (HBV) were examined in HepAD38 cells and HBV-infected HepG2-NTCP cells. Results: The dual-luciferase reporter assays showed that the EFTUD2 promoter hEFTUD2pro-0.5 kb had the strongest activity. In Epro-LUC-HepG2 cells, plerixafor and resatorvid significantly upregulated the activity of the EFTUD2 promoter and the expression of the gene and protein. In HepAD38 cells and HBV-infected HepG2-NTCP cells, treatment with plerixafor and resatorvid strongly inhibited HBsAg, HBV DNA, HBV RNAs, and cccDNA in a dose-dependent manner. Furthermore, the anti-HBV effect was enhanced when entecavir was administered along with either of the previous two compounds, and the effect could be blocked by knocking down EFTUD2. Conclusion: We established a convenient model for screening compounds that target EFTUD2 and further identified plerixafor and resatorvid as novel HBV inhibitors in vitro. Our findings provided information on the development of a new class of anti-HBV agents that act on host factors rather than viral enzymes.

High RIG-I and EFTUD2 expression predicts poor survival in endometrial cancer.

PURPOSE: Endometrial cancer is the most common gynecological malignancy. The helicase RIG-I, a part of the innate immune system, and EFTUD2, a splicing factor which can upregulate RIG-I expression, are shown to influence tumor growth and disease progression in several malignancies. For endometrial cancer, an immunogenic cancer, data about RIG-I and EFTUD2 are still missing. The aim of this study was to examine the expression of RIG-I and EFTUD2 in endometrial cancer. METHODS: 225 specimen of endometrial cancer were immunohistochemically stained for RIG-I and EFTUD2. The results were correlated to clinicopathological data, overall survival (OS) and progression-free survival (PFS). RESULTS: High RIG-I expression correlated with advanced tumor stages (FIGO: p = 0.027; pT: p = 0.010) and worse survival rates (OS: p = 0.009; PFS: p = 0.022). High EFTUD2 expression correlated to worse survival rates (OS: p = 0.026; PFS: p < 0.001) and was determined to be an independent marker for progression-free survival. CONCLUSION: Our data suggest that the expression of RIG-I and EFTUD2 correlates with survival data, which makes both a possible therapeutic target in the future.

Spliceosomal GTPase Eftud2 regulates microglial activation and polarization.

Elongation factor Tu GTP binding domain protein 2 (Eftud2) is a spliceosomal GTPase that serves as an innate immune modulator restricting virus infection. Microglia are the resident innate immune cells and the key players of immune response in the central nervous system. However, the role of Eftud2 in microglia has not been reported. In this study, we performed immunofluorescent staining and western blot assay and found that Eftud2 was upregulated in microglia of a 5xFAD transgenic mouse model of Alzheimer's disease. Next, we generated an inducible microglia-specific Eftud2 conditional knockout mouse line (CX3CR1-CreER; Eftud2f/f cKO) via Cre/loxP recombination and found that Eftud2 deficiency resulted in abnormal proliferation and promoted anti-inflammatory phenotype activation of microglia. Furthermore, we knocked down Eftud2 in BV2 microglia with siRNA specifically targeting Eftud2 and found that Eftud2-mediated regulation of microglial proinflammatory/anti-inflammatory phenotype activation in response to inflammation might be dependent on the NF-κB signaling pathway. Our findings suggest that Eftud2 plays a key role in regulating microglial polarization and homeostasis possibly through the NF-κB signaling pathway.

U5 snRNP Core Proteins Are Key Components of the Defense Response against Viral Infection through Their Roles in Programmed Cell Death and Interferon Induction.

The spliceosome is a massive ribonucleoprotein structure composed of five small nuclear ribonucleoprotein (snRNP) complexes that catalyze the removal of introns from pre-mature RNA during constitutive and alternative splicing. EFTUD2, PRPF8, and SNRNP200 are core components of the U5 snRNP, which is crucial for spliceosome function as it coordinates and performs the last steps of the splicing reaction. Several studies have demonstrated U5 snRNP proteins as targeted during viral infection, with a limited understanding of their involvement in virus-host interactions. In the present study, we deciphered the respective impact of EFTUD2, PRPF8, and SNRNP200 on viral replication using mammalian reovirus as a model. Using a combination of RNA silencing, real-time cell analysis, cell death and viral replication assays, we discovered distinct and partially overlapping novel roles for EFTUD2, PRPF8, and SNRNP200 in cell survival, apoptosis, necroptosis, and the induction of the interferon response pathway. For instance, we demonstrated that EFTUD2 and SNRNP200 are required for both apoptosis and necroptosis, whereas EFTUD2 and PRPF8 are required for optimal interferon response against viral infection. Moreover, we demonstrated that EFTUD2 restricts viral replication, both in a single cycle and multiple cycles of viral replication. Altogether, these results establish U5 snRNP core components as key elements of the cellular antiviral response.