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

80 μg of small interfering RNA (siRNA) powder (negative control or siRNA‐DLX5) were centrifuged, and mixed with 100 μl of 5% glucose solution thoroughly; then, 8 μl of in vivo jetPEI™ and 92 μl of 5% glucose solution were mixed together, followed by incubation with solution obtained in step (1) in greenhouse for 20 min (200 μl in total).

Uremia largely results from the accumulation of organic waste products normally cleared by the kidneys, which commonly accompanies kidney failure and chronic kidney disease. However, genetic investigations in a uremia remain largely unclear. This study aimed to determine the expression patterns of distal-less homeobox 5 (DLX5) in uremia rat model and further to study its effects on glomerulosclerosis and interstitial fibrosis. Uremic expression chip was applied to screen differentially expressed genes in uremia. Next, we used small interfering RNA-mediated RNA interference to specifically silence DLX5 in experimental uremic rats to understand the regulatory mechanism of DLX5. To understand effect of Notch1 signaling pathway in uremia, we also treated experimental uremic rats with gamma-secretase inhibitor (GSI), an inhibitor of Notch1 signaling pathway. The expression of fibronectin (FN), laminin (LN), transforming growth factor-beta1 (TGF-beta1), Hes1, Hes5, and Jagged2 was determined. The semiquantitative assessment was applied to verify the effects of DLX5 on glomerulosclerosis. In the uremic expression chip, we found that DLX5 was upregulated in uremia samples, and considered to regulate the Notch signaling pathway. We found that small interfering RNA-mediated DLX5 inhibition or Notch1 signaling pathway inhibitory treatment relieved and delayed the kidney injury and glomerulosclerosis in uremia. Meanwhile, inhibition of DLX5 or Nothch1 signaling pathway reduced expression of FN, LN, Nothch1, TGF-beta1, Hes1, Hes5, and Jagged2. Intriguingly, we discovered that Notch1 signaling pathway was inhibited after silencing DLX5. In conclusion, these findings highlight that DLX5 regulates Notch signaling, which may, in turn, promote complications of uremia such as kidney fibrosis, providing a novel therapeutic target for treating uremia.