MOS mutation causes female infertility with large polar body oocytes.

The Moloney sarcoma oncogene (MOS) encodes a protein serine/threonine kinase and MOS is expressed at high levels in oocytes undergoing meiotic maturation. The MOS/MAPK pathway is normally required for the maintenance of microtubules and chromatin in a metaphasic state during the meiotic divisions. To determine the pathogenic genes in a female infertile patient due to large polar body oocytes, whole-exome sequencing was performed on the patient and available family members. We identified a novel homozygous missense mutation c.591T > G in MOS. Bioinformatics analysis showed that the mutation is harmful. These findings suggest that MOS mutation results in oocytes with a large polar body and poor embryonic development in patients. The MOS variant may regulate oocyte asymmetric division by MAPK/WAVE2/Arp2/3/actin signaling pathway. This will help to understand the comprehensive role of MOS in early human reproductive process and provide genetic markers for future genetic counseling for more individualized treatments.

MARVELD1 attenuates arsenic trioxide-induced apoptosis in liver cancer cells by inhibiting reactive oxygen species production.

BACKGROUND: Arsenic trioxide (As2O3) is widely used for the treatment of acute promyelocytic leukemia (APL), and more recently, has also been applied to solid tumors. However, there are a fraction of patients with solid tumors, such as liver cancer, who respond to As2O3 treatment poorly. The underlying mechanisms for this remain unclear. METHODS: We determined the suitable concentration of drugs by IC50. Cell Counting Kit-8 (CCK-8) and flow cytometry were used to analyze the apoptosis. Morphological changes of the cells were observed by laser scanning confocal microscopy. Furthermore, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by flow cytometry. Quantitative polymerase chain reaction (qPCR) and Western blot tests were conducted to detect the mRNA and protein levels in different groups. Finally, a xenograft tumor assay and histopathological analysis were performed to evaluate the MARVELD1 function in cell proliferation and apoptosis. RESULTS: Here, we show that MARVELD1 enhances the therapeutic effects of epirubicin, while inducing the strong resistance of liver cancer cells to As2O3 treatment. We further demonstrate that the As2O3-induced apoptosis was inhibited by MARVELD1 overexpression (24 h Vector vs. MARVELD1 =30.58% vs. 17.41%, P<0.01; 48 h Vector vs. MARVELD1 =46.50% vs. 21.02%, P<0.01), possibly through inhibiting ROS production by enhancing TRXR1 expression. In vivo, we found a significantly increased size (Vector vs. MARVELD1 =203.90±21.92 vs. 675.70±37.84 mm3, P<0.001) and weight (Vector vs. MARVELD1 =0.19±0.02 vs. 0.58±0.05 g, P<0.001) of tumors with high expression of MARVELD1 after As2O3 treatment. Consistently, a higher expression of MARVELD1 predicted a poor prognosis for liver cancer patients. CONCLUSIONS: Our data identified a unique role of MARVELD1 in As2O3-induced apoptosis and As2O3 cancer therapy resistance.

Mmu-miR-185 depletion promotes osteogenic differentiation and suppresses bone loss in osteoporosis through the Bgn-mediated BMP/Smad pathway.

MicroRNAs (miRs) play an essential role in the regulation of bone formation and homeostasis. miR-185 has been reported to negatively regulate osteogenesis in vitro. However, whether it has an impact on in vivo bone homeostasis remains unknown. Here, we demonstrated that primary osteoblasts and mesenchymal stem cells derived from miR-185-knockout (KO) mice exhibited enhanced osteogenesis. Further, we constructed an ovariectomized mouse model to investigate the role of miR-185 during osteoporosis. Micro-computed tomography revealed an increased bone volume in KO compared to wild-type mice 6 weeks after surgery, indicating redundant bone formation after miR-185 depletion. Dual-luciferase reporter assays identified biglycan (Bgn), which promotes bone formation through the BMP/Smad pathway, as the direct target of miR-185. Taken together, these findings indicate that blocking miR-185 expression increases bone formation during osteoporosis, which may partly occur through the regulation of Bgn expression and BMP/Smad signaling.

GXYLT2 accelerates cell growth and migration by regulating the Notch pathway in human cancer cells.

Glucoside xylosyltransferase2 (GXYLT2), a member of the human α-1,3-D-xylosyltransferases, functions to modify the first xylose to the O-Glucose residue on epidermal growth factor (EGF) repeats of Notch receptors. It is well-established that the Notch signaling pathway plays a critical role in proper development and homeostasis. However, the regulatory role of EGF xylosylation in Notch signaling and different cell activities in human cells remains unknown. In this study, we showed that knockdown of GXYLT2 suppressed human cell proliferation and induced G1/S phase cell cycle arrest. GXYLT2 downregulation also inhibited cell migration and invasion, whereas the overexpression of GXYLT2 had the opposite effects. Additionally, GXYLT2 activated Notch signaling and promoted the phosphorylation of MAPKs but not PI3K and Akt. Taken together, our findings indicated that GXYLT2 plays an important role in cell activities via regulation of the Notch signaling.

Nop-7-associated 2 (NSA2) is required for ribosome biogenesis and protein synthesis.

Ribosome biogenesis is a fundamental cellular process and occurs mainly in the nucleolus in eukaryotes. The process is exceptionally complex and highly regulated by numerous ribosomal and non-ribosomal factors. A recent discovery strengthened the link between ribosome biogenesis and malignant transformation. Here, we determined that Nop-7-associated 2 (NSA2) is a nucleolar protein required for ribosome biogenesis. NSA2 knockdown reduced the rate of rRNA synthesis, diminishing the 60S ribosomal subunit. Moreover, we demonstrated that depletion of NSA2 suppressed protein synthesis. To investigate the signaling pathway affected by NSA2, NSA2 was depleted, which triggered the inactivation of the mTOR signaling pathway. Taken together, our findings reveal a novel function of NSA2 and provide insight into the regulation of ribosome biogenesis by NSA2.

mmu-miR-1963 negatively regulates the ameloblast differentiation of LS8 cell line by directly targeting Smoc2 3'UTR.

RUNX2 is a key regulator of osteogenic differentiation and odontoblastic differentiation. RUNX2 mutations could cause Cleidocranial dysplasia (CCD; OMIM119600), which is featured by abnormal development of bone and teeth. By using microRNA array, we identified a large number of microRNAs that showed different expression between wild-type Runx2 group and mutant groups. The aim of this study is to find out the effect of mmu-miR-1963, which was downregulated in all mutant Runx2 groups, on the ameloblast differentiation of LS8 cells. qPCR and Western Blot results showed the suppressive effect of mmu-miR-1963 on ameloblast differentiation of LS8 cell line. We further confirmed Smoc2 as one direct target of mmu-miR-1963. For the first time, we showed that mmu-miR-1963 could regulate the ameloblast differentiation of LS8 by targeting Smoc2. This study suggests the suppressive role of mmu-miR-1963 on ameloblast differentiation of LS8 via directly targeting the 3'UTR of Smoc2. We also demonstrated that Smoc2 itself could promote the ameloblast differentiation of LS8 for the first time. Our results indicate a novel explanation to the enamel hypoplasia phenotype in part of CCD patients.