WDR12, a Member of Nucleolar PeBoW-Complex, Is Up-Regulated in Failing Hearts and Causes Deterioration of Cardiac Function

circMIRIAF aggravates myocardial ischemia-reperfusion injury via targeting miR-544/WDR12 axis

Exploring and discovering novel circRNAs is one of the ways to develop innovative drugs for the diagnosis and treatment of myocardial ischemia-reperfusion injury (MI/RI). In the work, some dysregulated circRNAs were found by microarray screening analysis in AC16 cells, and hsa_circRNA_104852 named circMIRIAF was screened, which was up-regulated in AC16 cells damaged by hypoxia-reoxygenation injury (H/RI). The comprehensive analysis of ceRNA network revealed the potential relationship of circMIRIAF/miR-544/WDR12. Then, the results of interaction research confirmed that circMIRIAF acted as sponge of miR-544 to positively regulate WDR12 protein expression. Further, the validation results indicate that miR-544 silencing increased the expression of WDR12, and WDR12 activated Notch1 signal to aggravate H/RI of AC16 cells and MI/RI of mice via regulating oxidative stress and inflammation. Furthermore, silencing circMIRIAF caused the decreased circMIRIAF levels and the increased miR-544 levels in cardiomyocytes, while excessive miR-544 inhibited WDR12 expression to alleviate the disorder. On the contrary, excessive circMIRIAF increased WDR12 expression by adsorbing miR-544 to exacerbate H/RI in AC16 cells. In addition, circMIRIAF siRNA reversed the aggravation of H/RI in cells caused by WDR12 overexpression. Overall, circMIRIAF can serve as a drug target or treating MI/RI, and circMIRIAF could sponge miR-544 and enhance WDR12 expression to aggravate MI/RI, which may provide a novel therapeutic strategy for MI/RI treatment.

Integrative analysis of WDR12 as a potential prognostic and immunological biomarker in multiple human tumors

Background: Mammalian WD-repeat protein 12 (WDR12), a family member of proteins containing repeats of tryptophan-aspartic acid (WD), is a potential homolog of yeast Ytm1p and consists of seven repeats of WD. Aim of the study: This study aims to investigate the potential oncogenic effects of WDR12 in various human malignancies throughout a pan-cancer analysis that has been carried out to examine the various patterns in which this gene is expressed and behaves in tumor tissues. Methods: Herein, we used The Cancer Genome Atlas (TCGA) and various computational tools to explore expression profiles, prognostic relevance, genetic mutations, immune cell infiltration, as well as the functional characteristics of WDR12 in multiple human cancers. Results: We found that WDR12 was inconsistently expressed in various cancers and that variations in WDR12 expression predicted survival consequences for cancer patients. Furthermore, we observed a significant correlation between WDR12 gene mutation levels and the prognosis of some tumors. Furthermore, significant correlations were found between WDR12 expression patterns and cancer-associated fibroblast (CAF) infiltration, myeloid-derived suppressor cells (MDSCs), tumor mutation burden, microsatellite instability and immunoregulators. Ultimately, pathway enrichment analysis revealed that WDR12-related pathways are involved in carcinogenesis. Conclusions: The findings of our study are stisfactory, demonstrating that WDR12 could serve as a promising reliable prognostic biomarker, as well as a therapeutic target for novel cancer therapeutic approaches.

Integrative genomic analyses identify WDR12 as a novel oncogene involved in glioblastoma

Glioblastoma (GBM) is the most malignant primary brain tumor in adults. Due to its invasive nature, it cannot be thoroughly eliminated. WD repeat domain 12 (WDR12) processes the 32S precursor rRNA but cannot affect the synthesis of the 45S/47S primary transcript. In this study, we found that WDR12 is highly expressed in GBM according to the analysis results of mRNA expression by The Cancer Genome Atlas database. The high expression level of WDR12 is dramatically related to shorter overall survival and reduced disease-free survival. Next, we knocked down WDR12 and found that knockdown of WDR12 promoted the apoptosis and inhibited the proliferation by cell biology experiments. Differential expression genes in gene-chip revealed that WDR12 knockdown mainly inhibited cell cycle. Finally, we also found that WDR12 is associated with PLK1 and EZH2 in cell proliferation of GBM. Resumptively, this report showed a possible evidence that WDR12 drove malignant behavior of GBM, whose expression may present a neoteric independent prognostic biomarker in GBM.

Phosphorylation of GATA4 at serine 105 is required for left ventricular remodelling process in angiotensin II-induced hypertension in rats

In this study, we investigated whether local intramyocardial GATA4 overexpression affects the left ventricular (LV) remodelling process and the importance of phosphorylation at serine 105 (S105) for the actions of GATA4 in an angiotensin II (AngII)‐induced hypertension rat model. Adenoviral constructs overexpressing wild‐type GATA4 or GATA4 mutated at S105 were delivered into the anterior LV free wall. AngII (33.3 µg/kg/h) was administered via subcutaneously implanted minipumps. Cardiac function and structure were examined by echocardiography, followed by histological immunostainings of LV sections and gene expression measurements by RT‐qPCR. The effects of GATA4 on cultured neonatal rat ventricular fibroblasts were evaluated. In AngII‐induced hypertension, GATA4 overexpression repressed fibrotic gene expression, reversed the hypertrophic adult‐to‐foetal isoform switch of myofibrillar genes and prevented apoptosis, whereas histological fibrosis was not affected. Overexpression of GATA4 mutated at S105 resulted in LV chamber dilatation, cardiac dysfunction and had minor effects on expression of myocardial remodelling genes. Fibrotic gene expression in cardiac fibroblasts was differently affected by overexpression of wild‐type or mutated GATA4. Our results indicate that GATA4 reduces AngII‐induced responses by interfering with pro‐fibrotic and hypertrophic gene expressions. GATA4 actions on LV remodelling and fibroblasts are dependent on phosphorylation site S105.

Mechanical stretch induced transcriptomic profiles in cardiac myocytes

Mechanical forces are able to activate hypertrophic growth of cardiomyocytes in the overloaded myocardium. However, the transcriptional profiles triggered by mechanical stretch in cardiac myocytes are not fully understood. Here, we performed the first genome-wide time series study of gene expression changes in stretched cultured neonatal rat ventricular myocytes (NRVM)s, resulting in 205, 579, 737, 621, and 1542 differentially expressed (>2-fold, P < 0.05) genes in response to 1, 4, 12, 24, and 48 hours of cyclic mechanical stretch. We used Ingenuity Pathway Analysis to predict functional pathways and upstream regulators of differentially expressed genes in order to identify regulatory networks that may lead to mechanical stretch induced hypertrophic growth of cardiomyocytes. We also performed micro (miRNA) expression profiling of stretched NRVMs, and identified that a total of 8 and 87 miRNAs were significantly (P < 0.05) altered by 1-12 and 24-48 hours of mechanical stretch, respectively. Finally, through integration of miRNA and mRNA data, we predicted the miRNAs that regulate mRNAs potentially leading to the hypertrophic growth induced by mechanical stretch. These analyses predicted nuclear factor-like 2 (Nrf2) and interferon regulatory transcription factors as well as the let-7 family of miRNAs as playing roles in the regulation of stretch-regulated genes in cardiomyocytes.

Elevated ambulatory systolic-diastolic pressure regression index is genetically determined in hypertensive patients with coronary heart disease

OBJECTIVES

Ambulatory systolic-diastolic pressure regression index (ASDPRI) as a composite marker of cardiovascular (CV) properties is related to CV complications. However, genetic determinants of ASDPRI are not known. The aim of this study is to report the relationship between certain single nucleotide polymorphisms (SNP) and ASDPRI in hypertensive patients with CAD confirmed by coronary angiography.

METHODS

A total of 1345 hypertensive subjects with CAD were included. SNPs were selected from genome-wide association studies. SNPs were reported to be associated with coronary artery disease risk. There were significant differences in 24 h and daytime and nighttime ASDPRIs for PHCTR1, LPA and ADAMTS7 polymorphisms. Genetic risk score (GRS18) was constructed to evaluate additive effect of 18 SNPs for ASDPRI.

RESULTS

Analysis of covariance revealed a significant relationship between the PPAB2B (β - 0.85; 95 CI -1.85--0.16, p < 0.02), WDR12 (β - 1.31; 95 CI -2.19--0.43, p < 0.01) polymorphisms and nighttime ASDPRI dipping. Analysis of covariance revealed a significant relationship between GRS 18 and 24-h ASDPRI (β 0.34; 95 CI 0.16-0.31, p < 0.01).

CONCLUSIONS

In conclusion, ADAMTS7 and LPA polymorphisms are related to 24-h ASDPRI but PPAB2B and WDR12 gene polymorphisms are associated with nighttime ASDPRI dipping. A total of 24-h ASDPRI is determined by GRS18.

The Crystal Structure of the Ubiquitin-like Domain of Ribosome Assembly Factor Ytm1 and Characterization of Its Interaction with the AAA-ATPase Midasin

The synthesis of eukaryotic ribosomes is a complex, energetically demanding process requiring the aid of numerous non-ribosomal factors, such as the PeBoW complex. The mammalian PeBoW complex, composed of Pes1, Bop1, and WDR12, is essential for the processing of the 32S preribosomal RNA. Previous work in Saccharomyces cerevisiae has shown that release of the homologous proteins in this complex (Nop7, Erb1, and Ytm1, respectively) from preribosomal particles requires Rea1 (midasin or MDN1 in humans), a large dynein-like protein. Midasin contains a C-terminal metal ion-dependent adhesion site (MIDAS) domain that interacts with the N-terminal ubiquitin-like (UBL) domain of Ytm1/WDR12 as well as the UBL domain of Rsa4/Nle1 in a later step in the ribosome maturation pathway. Here we present the crystal structure of the UBL domain of the WDR12 homologue from S. cerevisiae at 1.7 Å resolution and demonstrate that human midasin binds to WDR12 as well as Nle1 through their respective UBL domains. Midasin contains a well conserved extension region upstream of the MIDAS domain required for binding WDR12 and Nle1, and the interaction is dependent upon metal ion coordination because removal of the metal or mutation of residues that coordinate the metal ion diminishes the interaction. Mammalian WDR12 displays prominent nucleolar localization that is dependent upon active ribosomal RNA transcription. Based upon these results, we propose that release of the PeBoW complex and subsequent release of Nle1 by midasin is a well conserved step in the ribosome maturation pathway in both yeast and mammalian cells.