Deltex E3 ubiquitin ligase 4 promotes thyroid cancer progression through stearoyl-CoA desaturase 1.

In this study, we aimed to explore the molecular role of Deltex E3 ubiquitin ligase 4 (DTX4) in thyroid cancer (TC) both in vitro and in vivo. The expression level of DTX4 in TC tissues was compared using The Cancer Genome Atlas (TCGA) database. We subsequently evaluated cell proliferation and migration in DTX4 knock down or DTX4 overexpression TC cell lines (TPC-1 and K1) by CCK-8, cell colony formation, and transwell assays. RNA sequencing and KEGG analysis were employed to identify potential genes that interact with DTX4. Our results showed that DTX4 was expressed at higher levels in both TC tissues and cells compared to normal controls. Knock down of DTX4 expression significantly inhibited TC cell progression in vitro. Furthermore, knockdown of endogenous DTX4 by shDTX4 markedly abrogated tumor growth, with significantly smaller tumor size and lower tumor weight in the shDTX4 group compared to the shCtrl group. Conversely, overexpression of DTX4 enhanced TC cell proliferation and migration. Through RNA sequencing, we identified 590 Differentially Expressed Genes (DEGs), with stearoyl-CoA desaturase 1 (SCD) ranking as the top gene. A positive correlation between DTX4 and SCD was observed in TC samples. Additionally, treatment with an SCD inhibitor, A939572, significantly rescued the enhanced growth effect induced by DTX4 overexpression. In conclusion, this study demonstrated that DTX4 promotes TC progression through SCD, indicating that the DTX4/SCD axis could be a promising target for TC therapy.

E3 ubiquitin ligase DTX4 is required for adipogenic differentiation in 3T3-L1 preadipocytes cell line.

Deltex4 (DTX4) is a member of the Deltex family of proteins. To date several lines of evidences suggest that Deltex family of proteins is closely linked to cell development and cell differentiation. However, little is known about the role of DTX4 in adipogenic differentiation. In this study, we assessed the impact of DTX4 on adipogenic differentiation in vitro, we found that DTX4 protein expression gradually increased during adipogenic differentiation of 3T3-L1 preadipocytes cell line. While DTX4 stable knockdown by recombinant shRNA lentivirus (sh-DTX4) notably reduced the number of lipid droplets and down-regulated the expression of adipogenic transcription factors C/EBPα and PPARγ and adipogenic markers gene FABP4 and Adipsin. Besides, cell numbers and incorporation of 5-Ethynyl-2'-deoxyuridine (EdU) into cells were significantly decreased during mitotic clonal expansion (MCE) in sh-DTX4 cells postinduction. Furthermore, compared to recombinant shRNA lentivirus control group (sh-CON), the mRNA levels of Wnt signaling genes such as Wnt6, Wnt10b and ß-catenin, were obviously elevated in sh-DTX4 group at day 3 of postinduction. Taken together, our results indicate that DTX4 stable knockdown inhibits adipogenesis of 3T3-L1 cells through inhibiting C/EBPα and PPARγ, arresting mitotic clonal expansion and regulating Wnt signaling pathway.

Quantitative trait loci on chromosomes 9 and 19 modulate AII amacrine cell number in the mouse retina.

Sequence variants modulating gene function or expression affect various heritable traits, including the number of neurons within a population. The present study employed a forward-genetic approach to identify candidate causal genes and their sequence variants controlling the number of one type of retinal neuron, the AII amacrine cell. Data from twenty-six recombinant inbred (RI) strains of mice derived from the parental C57BL/6J (B6/J) and A/J laboratory strains were used to identify genomic loci regulating cell number. Large variation in cell number is present across the RI strains, from a low of ∼57,000 cells to a high of ∼87,000 cells. Quantitative trait locus (QTL) analysis revealed three prospective controlling genomic loci, on Chromosomes (Chrs) 9, 11, and 19, each contributing additive effects that together approach the range of variation observed. Composite interval mapping validated two of these loci, and chromosome substitution strains, in which the A/J genome for Chr 9 or 19 was introgressed on a B6/J genetic background, showed increased numbers of AII amacrine cells as predicted by those two QTL effects. Analysis of the respective genomic loci identified candidate controlling genes defined by their retinal expression, their established biological functions, and by the presence of sequence variants expected to modulate gene function or expression. Two candidate genes, Dtx4 on Chr 19, being a regulator of Notch signaling, and Dixdc1 on Chr 9, a modulator of the WNT-ß-catenin signaling pathway, were explored in further detail. Postnatal overexpression of Dtx4 was found to reduce the frequency of amacrine cells, while Dixdc1 knockout retinas contained an excess of AII amacrine cells. Sequence variants in each gene were identified, being the likely sources of variation in gene expression, ultimately contributing to the final number of AII amacrine cells.

Combined Methylome and Transcriptome Analysis During Rat Hepatic Stellate Cell Activation.

Hepatic stellate cells (HSCs) are mesenchymal stem cells (MSCs) of the liver. They are unique among MSCs, since HSCs remain in a quiescent, retinoid-storing state in the normal liver but become activated after liver injury and contribute to tissue repair. The epigenetic mechanisms accompanying the transition of HSCs from a quiescent to an activated state are in the focus of the present study. We investigated the methylome and transcriptome during this process and observed profound changes. While the promoter methylation correlated negatively with gene expression, the gene-body methylation revealed no clear correlation. Most genes with altered expression were associated with cell differentiation. Among them, Wilms tumor 1 (Wt1) and Deltex4 (Dtx4) genes were identified as epigenetically regulated. Since HSCs were reported to derive from multipotent Wt1-positive cells and many differentially expressed genes were associated with cell differentiation during their activation, epigenetic alterations are presumably required to enable HSC development.

Systems biology combining human- and animal-data miRNA and mRNA data identifies new targets in ureteropelvic junction obstruction.

BACKGROUND: Although renal fibrosis and inflammation have shown to be involved in the pathophysiology of obstructive nephropathies, molecular mechanisms underlying evolution of these processes remain undetermined. In an attempt towards improved understanding of obstructive nephropathy and improved translatability of the results to clinical practice we have developed a systems biology approach combining omics data of both human and mouse obstructive nephropathy. RESULTS: We have studied in parallel the urinary miRNome of infants with ureteropelvic junction obstruction and the kidney tissue miRNome and transcriptome of the corresponding neonatal partial unilateral ureteral obstruction (UUO) mouse model. Several hundreds of miRNAs and mRNAs displayed changed abundance during disease. Combination of miRNAs in both species and associated mRNAs let to the prioritization of five miRNAs and 35 mRNAs associated to disease. In vitro and in vivo validation identified consistent dysregulation of let-7a-5p and miR-29-3p and new potential targets, E3 ubiquitin-protein ligase (DTX4) and neuron navigator 1 (NAV1), potentially involved in fibrotic processes, in obstructive nephropathy in both human and mice that would not be identified otherwise. CONCLUSIONS: Our study is the first to correlate a mouse model of neonatal partial UUO with human UPJ obstruction in a comprehensive systems biology analysis. Our data revealed let-7a and miR-29b as molecules potentially involved in the development of fibrosis in UPJ obstruction via the control of DTX4 in both man and mice that would not be identified otherwise.