Project description:Calcium oxalate stones account for over 80% of urinary stones, while the molecular mechanism of its formation is still not completely elucidated. The incidence of hyperoxaluria in calcium oxalate stone formation ranks only second to hypercalciuria. It plays an important role in the pathophysiological process of stone formation. We analyzed miRNA expression profiles between experimental hyperoxaluric rats and normal rats in order to find out the target genes and signaling pathways in the pathogenesis of hyperoxaluria.
Project description:Kidney stone disease causes significant morbidity and increases health care utilization. The pathogenesis of stone disease is incompletely understood, due in part to the poor characterization of the cellular and molecular makeup of the human papilla and its alteration with disease. In this work, we characterize the human renal papilla in health and calcium oxalate stone disease using single nuclear RNA sequencing, spatial transcriptomics and high-resolution large scale multiplexed 3D and Co-Detection by indexing (CODEX) imaging. We define and localize subtypes of principal cells enriched in the papilla as well as immune and stromal cell populations. We further uncovered an undifferentiated epithelial cell signature in the papilla, particularly during nephrolithiasis.
Project description:Kidney stone disease causes significant morbidity and increases health care utilization. In this dataset, we applied a single-nucleus assay to renal papila samples in order to charachterize the cellular and molecular niches in patients with calcium oxalate (CaOx) stone disease and healthy subjects. In addition to identifying cell types important in papillary physiology, we characterize collecting duct cell subtypes and an undifferentiated epithelial cell type that was more prevalent in stone patients. Despite the focal nature of mineral deposition in nephrolithiasis, we uncover a global injury signature characterized by immune activation, oxidative stress and extracellular matrix remodeling. We also identify the association of MMP7 and MMP9 expression with stone disease and mineral deposition, respectively. MMP7 and MMP9 are significantly increased in the urine of patients with CaOx stone disease, and their levels correlate with disease activity. Our results define the spatial molecular landscape and specific pathways contributing to stone-mediated injury in the human papilla and identify associated urinary biomarkers.
Project description:Accumulation of oxalate in patients with chronic kidney disease (CKD) is associated with CKD progression and an increased risk of cardiac death. Whether reducing oxalate slows CKD progression and prevents cardiovascular complications remains unexplored. We colonized Oxalobacter formigenes (Oxf), an oxalate-degrading microbiome, in the intestines of control and CKD mice fed with 1% hydroxyproline for 23 weeks. RNA-seq analysis of heart tissues of CKD mice reveals dysregulated expression of metabolic pathways and Oxf colonization reverses these changes. These findings demonstrate that oxalate accumulation plays a role not only in CKD progression but also in cardiovascular complications.
Project description:Randall’s plaque (RP) is the origin of renal calcification on which idiopathic calcium oxalate (CaOx) kidney stones develop. To establish genomic pathogenesis of RP, we performed the microarray analysis for comparing the gene expressions among renal papillary RP and normal tissue of 23 CaOx and 6 calcium phosphate (CaP) stone formers, and normal papillary tissue of 7 control patients. Compare to normal papillary tissue, RP tissue contained up-regulation of lipocalin 2, interleukin 11, prostaglandin-endoperoxide synthase 1, glutathione peroxidase 3, and monocyte to macrophage differentiation, whereas down-regulation of solute carrier family 12 member 1 and sodium leak channel non selective (either > 2.0- or 0.5-fold, p <0.01). The network and toxicity analysis showed these genes had association with activated mitogen-activated protein kinase, Akt/ phosphatidylinositol 3-kinase pathway, and pro-inflammatory cytokines, which caused renal injury and oxidative stress.
Project description:Kidney stones (KS) are very common, excruciating, and are associated with tremendous healthcare cost, chronic kidney disease (CKD), and end stage renal disease (ESRD). Most KS are composed of calcium oxalate and very small increases in urine oxalate concentration increase the risk for stone formation. Besides its critical role in the pathogenesis of KS, emerging data suggest that disturbed oxalate homeostasis (hyperoxaluria and/or hyperoxalemia) contributes to CKD progression, CKD - and ESRD-associated cardiovascular diseases, progression of cyst growth in autosomal dominant polycystic kidney disease (ADPKD), and delayed graft function & poor renal allograft survival. This emphasizes the urgent need for plasma and urinary oxalate lowering therapies, and enhancing the bowel’s ability to secrete oxalate may effectively do so. We previously identified Oxalobacter formigenes (O. formigenes)-derived factors secreted in its culture conditioned medium (CM) which stimulated oxalate transport by human intestinal Caco2-BBE (C2) cells and reduced urinary oxalate excretion in hyperoxaluric mice by enhancing colonic oxalate secretion. Given their remarkable therapeutic potential, we now identified several proteins belonging to Sel1-like family as the major O. formigenes-derived secreted factors, and we determined the crystal structures for six proteins to better understand their function. Importantly, Sel1-14-derived small peptides P8 & P9 were identified as the major factors, with P8+9 closely recapitulate the CM’s effects, including acting through the oxalate transporters SLC26A2 & SLC26A6 and PKA activation. P8+9 also stimulate oxalate transport by human ileal and colonic organoids, confirming that these peptides work in human tissues. Collectively, the identification of these small peptides provide a great opportunity for developing a peptide-based novel therapeutic for hyperoxalemia, hyperoxaluria, and related disorders, impacting the outcomes of patients suffering from KS, primary hyperoxaluria, CKD, ADPKD, ESRD, and renal transplant recipients.
Project description:Morphine and its pharmacological derivatives are the most prescribed analgesics for moderate to severe pain management. However, chronic use of morphine reduces pathogen clearance and induces bacterial translocation across the gut barrier. The enteric microbiome has been shown to play a critical role in the preservation of the mucosal barrier function and metabolic homeostasis. Here, we show for the first time, using bacterial 16s rDNA sequencing, that chronic morphine treatment significantly alters the gut microbial composition and induces preferential expansion of the gram-positive pathogenic and reduction of bile-deconjugating bacterial strains. A significant reduction in both primary and secondary bile acid levels was seen in the gut, but not in the liver with morphine treatment. Morphine induced microbial dysbiosis and gut barrier disruption was rescued by transplanting placebo-treated microbiota into morphine-treated animals, indicating that microbiome modulation could be exploited as a therapeutic strategy for patients using morphine for pain management. In this study, we establish a link between the two phenomena, namely gut barrier compromise and dysregulated bile acid metabolism. We show for the first time that morphine fosters significant gut microbial dysbiosis and disrupts cholesterol/bile acid metabolism. Changes in the gut microbial composition is strongly correlated to disruption in host inflammatory homeostasis13,14 and in many diseases (e.g. cancer/HIV infection), persistent inflammation is known to aid and promote the progression of the primary morbidity. We show here that chronic morphine, gut microbial dysbiosis, disruption of cholesterol/bile acid metabolism and gut inflammation; have a linear correlation. This opens up the prospect of devising minimally invasive adjunct treatment strategies involving microbiome and bile acid modulation and thus bringing down morphine-mediated inflammation in the host.