An adenosine triphosphatase of the sucrose nonfermenting 2 family, androgen receptor-interacting protein 4, is essential for mouse embryonic development and cell proliferation

Estrogen associates with female predominance in Xp11.2 translocation renal cell carcinoma

Based on the epidemiological characteristics of susceptibility and age selectivity for women in Xp11.2 translocation renal cell carcinoma (Xp11.2 tRCC), we inferred that estrogen was to be blamed. Rad54 like 2 (Rad54l2) which might be one of key effector proteins of DNA damage mediated by estrogen was downregulated in numerous cancers, however, its role in epidemiological characteristics of Xp11.2 tRCC was needed to further study. We reviewed 1005 Xp11.2 tRCC cases and collected estrogen data and then compared the onset time of Xp11.2 tRCC cases in female with estrogen changing trend. An RNA-sequencing was performed in estrogen treated HK-2 cells and subsequently bioinformatic analysis was applied based on the Cancer Genome Atlas (TCGA) and GEO database. The male-to-female ratio of Xp11.2 tRCC was 1:1.4 and the median age of onset was 29.7 years old. The onset trend of female was similar to estrogen physiological rhythm (r = 0.67, p < 0.01). In Xp11.2 tRCC and HK-2 cells after estrogen treatment, Rad54l2 was downregulated, and GSEA showed that pathways significantly enriched in DNA damage repair and cancer related clusters after estrogen treated, as well as GO and KEGG analysis. Downregulation of Rad54l2 was in numerous cancers, including renal cell carcinoma (RCC), in which Rad54l2 expression was significantly decreased in male, age over 60 years old, T2&T3&T4 stages, pathologic SII&SIII&SIV stages as well as histologic G3&G4 grades, and cox regression analysis proved that Rad54l2 expression was a risk factor for overall survival, disease-specific survival and progression-free interval in univariate analysis. There existed female predominance in Xp11.2 tRCC and Rad54l2 might play vital role in estrogen mediating female predominance in Xp11.2 tRCC.

Irradiation-Induced Upregulation of miR-711 Inhibits DNA Repair and Promotes Neurodegeneration Pathways

Radiotherapy for brain tumors induces neuronal DNA damage and may lead to neurodegeneration and cognitive deficits. We investigated the mechanisms of radiation-induced neuronal cell death and the role of miR-711 in the regulation of these pathways. We used in vitro and in vivo models of radiation-induced neuronal cell death. We showed that X-ray exposure in primary cortical neurons induced activation of p53-mediated mechanisms including intrinsic apoptotic pathways with sequential upregulation of BH3-only molecules, mitochondrial release of cytochrome c and AIF-1, as well as senescence pathways including upregulation of p21^WAF1/Cip1. These pathways of irradiation-induced neuronal apoptosis may involve miR-711-dependent downregulation of pro-survival genes Akt and Ang-1. Accordingly, we demonstrated that inhibition of miR-711 attenuated degradation of Akt and Ang-1 mRNAs and reduced intrinsic apoptosis after neuronal irradiation; likewise, administration of Ang-1 was neuroprotective. Importantly, irradiation also downregulated two novel miR-711 targets, DNA-repair genes Rad50 and Rad54l2, which may impair DNA damage responses, amplifying the stimulation of apoptotic and senescence pathways and contributing to neurodegeneration. Inhibition of miR-711 rescued Rad50 and Rad54l2 expression after neuronal irradiation, enhancing DNA repair and reducing p53-dependent apoptotic and senescence pathways. Significantly, we showed that brain irradiation in vivo persistently elevated miR-711, downregulated its targets, including pro-survival and DNA-repair molecules, and is associated with markers of neurodegeneration, not only across the cortex and hippocampus but also specifically in neurons isolated from the irradiated brain. Our data suggest that irradiation-induced miR-711 negatively modulates multiple pro-survival and DNA-repair mechanisms that converge to activate neuronal intrinsic apoptosis and senescence. Using miR-711 inhibitors to block the development of these regulated neurodegenerative pathways, thus increasing neuronal survival, may be an effective neuroprotective strategy.

Defects in chondrocyte maturation and secondary ossification in mouse knee joint epiphyses due to Snorc deficiency

OBJECTIVE

The role of Snorc, a novel cartilage specific transmembrane proteoglycan, was studied during skeletal development using two Snorc knockout mouse models. Hypothesizing that Snorc, like the other transmembrane proteoglycans, may be a coreceptor, we also studied its interaction with growth factors.

METHODS

Skeletal development was studied in wild type (WT) and Snorc knockout mice during postnatal development by whole mount staining, X-ray imaging, histomorphometry, immunohistochemistry and qRT-PCR. Snorc promoter activity was studied by applying the LacZ reporter expressed by the targeting construct. Slot blot binding and cell proliferation assays were used to study the interaction of Snorc with several growth factors.

RESULTS

Snorc expression was localized in the knee epiphyses especially to the prehypertrophic chondrocytes delineating the cartilage canals and secondary ossification center (SOC). Snorc was demonstrated to have a glycosaminoglycan independent affinity to FGF2 and it inhibited FGF2 dependent cell growth of C3H101/2 cells. In Snorc deficient mice, SOCs in knee epiphyses were smaller, and growth plate (GP) maturation was disturbed, but total bone length was not affected. Central proliferative and hypertrophic zones were enlarged with higher extracellular matrix (ECM) volume and rounded chondrocyte morphology at postnatal days P10 and P22. Increased levels of Ihh and Col10a1, and reduced Mmp13 mRNA expression were observed at P10.

CONCLUSIONS

These findings suggest a role of Snorc in regulation of chondrocyte maturation and postnatal endochondral ossification. The interaction identified between recombinant Snorc core protein and FGF2 suggest functions related to FGF signaling.

Systematic evaluation of underlying defects in DNA repair as an approach to case-only assessment of familial prostate cancer

Risk assessment for prostate cancer is challenging due to its genetic heterogeneity. In this study, our goal was to develop an operational framework to select and evaluate gene variants that may contribute to familial prostate cancer risk. Drawing on orthogonal sources, we developed a candidate list of genes relevant to prostate cancer, then analyzed germline exomes from 12 case-only prostate cancer patients from high-risk families to identify patterns of protein-damaging gene variants. We described an average of 5 potentially disruptive variants in each individual and annotated them in the context of public databases representing human variation. Novel damaging variants were found in several genes of relevance to prostate cancer. Almost all patients had variants associated with defects in DNA damage response. Many also had variants linked to androgen signaling. Treatment of primary T-lymphocytes from these prostate cancer patients versus controls with DNA damaging agents showed elevated levels of the DNA double strand break (DSB) marker γH2AX (p < 0.05), supporting the idea of an underlying defect in DNA repair. This work suggests the value of focusing on underlying defects in DNA damage in familial prostate cancer risk assessment and demonstrates an operational framework for exome sequencing in case-only prostate cancer genetic evaluation.

Selective autophagic receptor p62 regulates the abundance of transcriptional coregulator ARIP4 during nutrient starvation

Transcriptional coregulators contribute to several processes involving nuclear receptor transcriptional regulation. The transcriptional coregulator androgen receptor-interacting protein 4 (ARIP4) interacts with nuclear receptors and regulates their transcriptional activity. In this study, we identified p62 as a major interacting protein partner for ARIP4 in the nucleus. Nuclear magnetic resonance analysis demonstrated that ARIP4 interacts directly with the ubiquitin-associated (UBA) domain of p62. ARIP4 and ubiquitin both bind to similar amino acid residues within UBA domains; therefore, these proteins may possess a similar surface structure at their UBA-binding interfaces. We also found that p62 is required for the regulation of ARIP4 protein levels under nutrient starvation conditions. We propose that p62 is a novel binding partner for ARIP4, and that its binding regulates the cellular protein level of ARIP4 under conditions of metabolic stress.

Extensive load of somatic CNVs in the human placenta

Placenta is a temporary, but indispensable organ in mammalian pregnancy. From its basic nature, it exhibits highly invasive tumour-like properties facilitating effective implantation through trophoblast cell proliferation and migration, and a critical role in pregnancy success. We hypothesized that similarly to cancer, somatic genomic rearrangements are promoted in the support of placental function. Here we present the first profiling of copy number variations (CNVs) in human placental genomes, showing an extensive load of somatic CNVs, especially duplications and suggesting that this phenomenon may be critical for normal gestation. Placental somatic CNVs were significantly enriched in genes involved in cell adhesion, immunity, embryonic development and cell cycle. Overrepresentation of imprinted genes in somatic duplications suggests that amplified gene copies may represent an alternative mechanism to support parent-of-origin specific gene expression. Placentas from pregnancy complications exhibited significantly altered CNV profile compared to normal gestations, indicative to the clinical implications of the study.