DLX5 gene regulates the Notch signaling pathway to promote glomerulosclerosis and interstitial fibrosis in uremic rats

Microencapsulated islet transplantation alleviates podocyte injury in diabetic nephropathy via inhibiting Notch-1 signaling

OBJECTIVE

Podocyte injury has a critical role in the pathogenesis of diabetic nephropathy (DN). Microencapsulated islet transplantation (MIT) is identified as an effective method for improving the clinical condition of DN. This study aimed to explore the role and mechanism of MIT in alleviating podocyte injury in DN.

METHODS

A mouse model of DN was constructed using streptozotocin (STZ). Mice were divided into 3 groups: the untreated diabetic nephropathy group (DN group), the microencapsulated islet transplantation-treated group (MIT group) and the control group. The mice were raised for 6 weeks posterior to islet transplantation to identify the role of MIT. Renal function and structure of glomerular filtration barrier were assessed by urine analysis, histopathological examination, and transmission electron microscopy. The expression levels of several proteins including Caspase-3, Bcl2/Bax, β-galactosidase, Ki-67, synaptopodin, WT-1, Jagged-1, Notch-1, and Hes-1 in renal tissues were identified via immunohistochemistry (IHC), immunofluorescence (IF), and western blotting techniques.

RESULTS

Compared with the DN group, the MIT group presented decreased levels of blood glucose, urinary albumin/creatinine, urea nitrogen, and serum creatinine while their body weight gradually increased. Glomerular injury in the MIT group was significantly better than that in the DN group. The MIT group indicated significantly decreased expression of Caspase-3, β-galactosidase, Bax/Bcl-2, and Ki-67 when compared with DN group, while the proportion of synaptopodin- and WT-1-positive cells was significantly increased (P < 0.05). The protein expression of Jagged-1, Notch-1, and Hes-1 in the glomerulus of the MIT group was significantly lower than that in the DN group (P < 0.05).

CONCLUSION

MIT alleviates podocyte injury induced by DN by inhibiting Notch-1 signaling. The identification of signaling pathways influencing podocyte restoration can help evaluate personalized medicine efficacy for patients treated with islet transplantation.

Advances in epigenetics in systemic sclerosis: molecular mechanisms and therapeutic potential

Systemic sclerosis (SSc) is a prototypical inflammatory fibrotic disease involving inflammation, vascular abnormalities and fibrosis that primarily affect the skin and lungs. The aetiology of SSc is unknown and its pathogenesis is only partially understood. Of all the rheumatic diseases, SSc carries the highest all-cause mortality rate and represents an unmet medical need. A growing body of evidence implicates epigenetic aberrations in this intractable disease, including specific modifications affecting the three main cell types involved in SSc pathogenesis: immune cells, endothelial cells and fibroblasts. In this Review, we discuss the latest insights into the role of DNA methylation, histone modifications and non-coding RNAs in SSc and how these epigenetic alterations affect disease features. In particular, histone modifications have a role in the regulation of gene expression pertinent to activation of fibroblasts to myofibroblasts, governing their fate. DNA methyltransferases are crucial in disease pathogenesis by mediating methylation of DNA in specific promoters, regulating expression of specific pathways. We discuss targeting of these enzymes for therapeutic gain. Innovative epigenetic therapy could be targeted to treat the disease in a precision epigenetics approach.

Differential DNA Methylation Landscape in Skin Fibroblasts from African Americans with Systemic Sclerosis

The etiology and reasons underlying the ethnic disparities in systemic sclerosis (SSc) remain unknown. African Americans are disproportionally affected by SSc and yet are underrepresented in research. The aim of this study was to comprehensively investigate the association of DNA methylation levels with SSc in dermal fibroblasts from patients of African ancestry. Reduced representation bisulfite sequencing (RRBS) was performed on primary dermal fibroblasts from 15 SSc patients and 15 controls of African ancestry, and over 3.8 million CpG sites were tested for differential methylation patterns between cases and controls. The dermal fibroblasts from African American patients exhibited widespread reduced DNA methylation. Differentially methylated CpG sites were most enriched in introns and intergenic regions while depleted in 5' UTR, promoters, and CpG islands. Seventeen genes and eleven promoters showed significant differential methylation, mostly in non-coding RNA genes and pseudogenes. Gene set enrichment analysis (GSEA) and gene ontology (GO) analyses revealed an enrichment of pathways related to interferon signaling and mesenchymal differentiation. The hypomethylation of DLX5 and TMEM140 was accompanied by these genes' overexpression in patients but underexpression for lncRNA MGC12916. These data show that differential methylation occurs in dermal fibroblasts from African American patients with SSc and identifies novel coding and non-coding genes.

NKL homeobox gene activities in normal and malignant myeloid cells

Recently, we have documented a hematopoietic NKL-code mapping physiological expression patterns of NKL homeobox genes in early hematopoiesis and in lymphopoiesis, which spotlights genes deregulated in lymphoid malignancies. Here, we enlarge this map to include normal NKL homeobox gene expressions in myelopoiesis by analyzing public expression profiling data and primary samples from developing and mature myeloid cells. We thus uncovered differential activities of six NKL homeobox genes, namely DLX2, HHEX, HLX, HMX1, NKX3-1 and VENTX. We further examined public expression profiling data of 251 acute myeloid leukemia (AML) and 183 myelodysplastic syndrome (MDS) patients, thereby identifying 24 deregulated genes. These results revealed frequent deregulation of NKL homeobox genes in myeloid malignancies. For detailed analysis we focused on NKL homeobox gene NANOG, which acts as a stem cell factor and is correspondingly expressed alone in hematopoietic progenitor cells. We detected aberrant expression of NANOG in a small subset of AML patients and in AML cell line NOMO-1, which served as a model. Karyotyping and genomic profiling discounted rearrangements of the NANOG locus at 12p13. But gene expression analyses of AML patients and AML cell lines after knockdown and overexpression of NANOG revealed regulators and target genes. Accordingly, NKL homeobox genes HHEX, DLX5 and DLX6, stem cell factors STAT3 and TET2, and the NOTCH-pathway were located upstream of NANOG while NKL homeobox genes HLX and VENTX, transcription factors KLF4 and MYB, and anti-apoptosis-factor MIR17HG represented target genes. In conclusion, we have extended the NKL-code to the myeloid lineage and thus identified several NKL homeobox genes deregulated in AML and MDS. These data indicate a common oncogenic role of NKL homeobox genes in both lymphoid and myeloid malignancies. For misexpressed NANOG we identified an aberrant regulatory network, which contributes to the understanding of the oncogenic activity of NKL homeobox genes.