Transcriptional study of hyperoxaluria and calcium oxalate nephrolithiasis in male rats: Inflammatory changes are mainly associated with crystal deposition

Abstract

Hyperoxaluria associated with renal deposition of calcium oxalate (CaOx) crystals causes renal injury and inflammation leading to number of diseases including chronic kidney disease (CKD). It is however, not been possible to separate the renal consequences of hyperoxaluria from that of CaOx crystal deposition. We decided to utilize ethylene glycol (EG) model where hyperoxaluria and CaOx crystal deposition can be separated in time. To test our hypothesis, male rats were made hyperoxaluric by administering EG, rats were euthanized and kidneys were extracted on day 14, when occasional crystal is seen in the kidneys and day 28, when all animals have developed renal CaOx crystal deposits. Total RNA was extracted for microarray analysis and genome wide analysis of differentially expressed genes was performed to investigate differences between hyperoxaluria and crystal induced alterations in the kidneys. Immunohistochemical and Hematoxylin and Eosin (H&E) staining was also done for macromolecules with significant role in stone formation. All EG fed rats became hyperoxaluric by day 7, showed a few crystal deposits on day 14, and had heavy crystal deposition by day 28. There were significant changes in the expression of genes encoding for NADPH Oxidases; macromolecular crystallization modulators; genes involved in inflammasome activation; and osteogenic marker genes. Results demonstrate major differences between hyperoxaluria and CaOx crystal induced changes in the kidneys. Injury and inflammation are mainly associated with crystal deposition indicating significant role played by crystal retention.

LncRNA HOXA11‐AS regulates calcium oxalate crystal–induced renal inflammation via miR‐124‐3p/MCP‐1

“…Meanwhile, CD44, another stone‐related gene considered as the receptor for OPN, was also overexpressed in this microarray . Moreover, in a recent microarray report using the ethylene glycol rat model, OPN, MCP‐1 and CD44 showed significantly up‐regulated expression . Therefore, we have been suggested that HOXA11‐AS might regulate the expression of these genes.…”

“…E, Dualluciferase reporter assays were performed using HK-2 cells con-transfected with control, WT MCP-1 3′UTR or MT MCP-1 3′UTR and miR-124-3p or miR-NC for 48 h. All values are expressed as the mean ± SD. **P < .01 vs WT MCP-1/ WT HOXA11-AS group microarray report from an ethylene glycol rat model 17 and observed several commonly up-regulated genes in these chips, among which, OPN, MCP-1 and CD44 have been widely accepted to play key roles in CaOx stone formation. As a result, we first tested whether HOXA11-AS could affect the expression of these three genes.…”

“…To identify downstream genes of HOXA11‐AS, we compared a previous microarray analysis conducted to investigate CaOx stone‐related mRNAs using the same animal model with another recent microarray report from an ethylene glycol rat model and observed several commonly up‐regulated genes in these chips, among which, OPN, MCP‐1 and CD44 have been widely accepted to play key roles in CaOx stone formation. As a result, we first tested whether HOXA11‐AS could affect the expression of these three genes.…”

“…*P < .5 vs control group, **P < .01 vs control group report using the ethylene glycol rat model, OPN, MCP-1 and CD44 showed significantly up-regulated expression. 17 Therefore, we have been suggested that HOXA11-AS might regulate the expression of these genes. Consequently, we first validated their expression in animal and cell models and, as expected, the results revealed their increased expression in vivo and in vitro.…”

A precision medicine approach uncovers a unique signature of neutrophils in patients with brushite kidney stones

“…To date, the tissues from these two highly contrasting forms of kidney stone disease have not been studied using modern techniques to disclose mechanisms of injury. A role for inflammation and oxidative injury has been proposed based on animal models of crystal induced injury or in vitro studies 3,4 . However, definitive evidence for such a role in human disease is limited.…”