Suppression of osteogenic-like differentiation in human renal interstitial fibroblasts by miRNA-410-3p through MSX2

Expression of osteogenic proteins in kidneys of cats with nephrocalcinosis

BACKGROUND

Nephrocalcinosis is a common pathological finding in cats with chronic kidney disease and nephrolithiasis. Understanding its pathogenesis may identify future therapeutic targets.

HYPOTHESIS

Nephrocalcinosis is associated with expression of an osteogenic phenotype.

ANIMALS

Kidneys with medullary mineralization were obtained from 18 cats (10 with and 8 without nephroliths) undergoing necropsy.

METHODS

Cross-sectional study. Microradiography and histopathology (modified von Kossa stain) were used to confirm parenchymal mineralization. Immunohistochemistry for 5 osteogenic markers was performed to determine their co-localization with nephrocalcinosis. The proportion of kidneys with stronger immunointensity in mineralized versus non-mineralized regions was analyzed using 1-tailed sign tests. The proportion of kidneys with co-localization of nephrocalcinosis and each marker was compared between kidneys with and without nephroliths using Fisher's exact tests.

RESULTS

Nephrocalcinosis co-localized with osteopontin immunoreactivity in all 18 cats (100%) and with osteocalcin in 12 cats (67%). Both osteogenic markers had stronger immunointensity in mineralized regions compared with non-mineralized regions. Limited co-localization was observed with other markers: bone morphogenic protein-2 in 2 kidneys (both with nephroliths) and tissue non-specific alkaline phosphatase in 1 kidney (without nephroliths); runt-related transcription factor-2 was undetected. No statistically significant differences were found in the co-localization of nephrocalcinosis with osteogenic proteins between kidneys with and without nephroliths.

CONCLUSIONS AND CLINICAL IMPORTANCE

Expression of osteogenic proteins in areas of nephrocalcinosis indicates that nephrocalcinosis is associated with the development of an osteogenic phenotype. Targeting these processes could offer a novel approach to prevent nephrolithiasis at its origin.

Noncoding RNA, friend or foe for nephrolithiasis?

Nephrolithiasis is one of the most common diseases in urology, characterized by notable incidence and recurrence rates, leading to significant morbidity and financial burden. Despite its prevalence, the precise mechanisms underlying stone formation remain incompletely understood, thus hindering significant advancements in kidney stone management over the past three decades. Investigating the pivotal biological molecules that govern stone formation has consistently been a challenging and high-priority task. A significant portion of mammalian genomes are transcribed into noncoding RNAs (ncRNAs), which have the ability to modulate gene expression and disease progression. They are thus emerging as a novel target class for diagnostics and pharmaceutical exploration. In recent years, the role of ncRNAs in stone formation has attracted burgeoning attention. They have been found to influence stone formation by regulating ion transportation, oxidative stress injury, inflammation, osteoblastic transformation, autophagy, and pyroptosis. These findings contributes new perspectives on the pathogenesis of nephrolithiasis. To enhance our understanding of the diagnostic and therapeutic potential of nephrolithiasis-associated ncRNAs, we summarized the expression profiles, biological functions, and clinical significance of these ncRNAs in the current review.

Identification of the core genes in Randall's plaque of kidney stone and immune infiltration with WGCNA network

Background: Randall's plaque is regarded as the precursor lesion of lithiasis. However, traditional bioinformatic analysis is limited and ignores the relationship with immune response. To investigate the underlying calculi formation mechanism, we introduced innovative algorithms to expand our understanding of kidney stone disease. Methods: We downloaded the GSE73680 series matrix from the Gene Expression Omnibus (GEO) related to CaOx formation and excluded one patient, GSE116860. In the RStudio (R version 4.1.1) platform, the differentially expressed genes (DEGs) were identified with the limma package for GO/KEGG/GSEA analysis in the clusterProfiler package. Furthermore, high-correlated gene co-expression modules were confirmed by the WGCNA package to establish a protein-protein interaction (PPI) network. Finally, the CaOx samples were processed by the CIBERSORT algorithm to anchor the key immune cells group and verified in the validation series matrix GSE117518. Results: The study identified 840 upregulated and 1065 downregulated genes. The GO/KEGG results revealed fiber-related or adhesion-related terms and several pathways in addition to various diseases identified from the DO analysis. Moreover, WGCNA selected highly correlated modules to construct a PPI network. Finally, 16 types of immune cells are thought to participate in urolithiasis pathology and are related to hub genes in the PPI network that are proven significant in the validation series matrix GSE117518. Conclusion: Randall's plaque may relate to genes DCN, LUM, and P4HA2 and M2 macrophages and resting mast immune cells. These findings could serve as potential biomarkers and provide new research directions.

NEAT1 functions as a key mediator of BMP2 to promote osteogenic differentiation of renal interstitial fibroblasts

Aim: To clarify the mechanism of NEAT1, an aberrantly upregulated lncRNA in Randall's plaques (RP) similar to biomineralization, in mediating osteogenic differentiation of human renal interstitial fibroblasts. Materials & methods: A comprehensive strategy of bioinformatic analysis and experimental verification was performed. Results: BMP2 silence abolished the osteogenic differentiation of human renal interstitial fibroblasts promoted by NEAT1. Mechanically, NEAT1 not only induced the nucleolar translocation of EGR1 binding to BMP2 promotor, but also functioned as a sponge of miR-129-5p in the cytoplasm to promote BMP2 expression. Moreover, there was a positive correlation between NEAT1 and BMP2 expression in RP instead of normal renal papilla. Conclusion: NEAT1 acted as a key mediator of BMP2 to promote human renal interstitial fibroblast osteogenic differentiation, through which NEAT1 might be involved in RP formation.

The role of microRNAs in the osteogenic and chondrogenic differentiation of mesenchymal stem cells and bone pathologies

Mesenchymal stem cells (MSCs) have been identified in many adult tissues. MSCs can regenerate through cell division or differentiate into adipocytes, osteoblasts and chondrocytes. As a result, MSCs have become an important source of cells in tissue engineering and regenerative medicine for bone tissue and cartilage. Several epigenetic factors are believed to play a role in MSCs differentiation. Among these, microRNA (miRNA) regulation is involved in the fine modulation of gene expression during osteogenic/chondrogenic differentiation. It has been reported that miRNAs are involved in bone homeostasis by modulating osteoblast gene expression. In addition, countless evidence has demonstrated that miRNAs dysregulation is involved in the development of osteoporosis and bone fractures. The deregulation of miRNAs expression has also been associated with several malignancies including bone cancer. In this context, bone-associated circulating miRNAs may be useful biomarkers for determining the predisposition, onset and development of osteoporosis, as well as in clinical applications to improve the diagnosis, follow-up and treatment of cancer and metastases. Overall, this review will provide an overview of how miRNAs activities participate in osteogenic/chondrogenic differentiation, while addressing the role of miRNA regulatory effects on target genes. Finally, the role of miRNAs in pathologies and therapies will be presented.