Differential modulation of PPARα and γ target gene expression in the liver and kidney of rats treated with aspirin

Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity

Lipotoxicity is the most common cause of severe kidney disease, with few treatment options available today. Precision toxicology can improve detection of subtle intracellular changes in response to exogenous substrates; thus, it facilitates in-depth research on bioactive molecules that may interfere with the onset of certain diseases. In the current study, troxerutin significantly relieved nephrotoxicity, increased endurance, and improved systemic energy metabolism and renal inflammation in OTA-induced nephrotic mice. Lipidomics showed that troxerutin effectively reduced the levels of triglycerides, phosphatidylcholines, and phosphatidylethanolamines in nephropathy. The mechanism was partly attributable to troxerutin in alleviating the aberrantly up-regulated expression of sphingomyelinase, the cystic fibrosis transmembrane conductance regulator, and chloride channel 2. Renal tubular epithelial cells, the main site of toxin-induced accumulation of lipids in the kidney, were subjected to transcriptomic profiling, which uncovered several metabolic factors relevant to aberrant lipid and lipoprotein metabolism. Our work provides new insights into the molecular features of toxin-induced lipotoxicity in renal tubular epithelial cells in vivo and demonstrates the function of troxerutin in alleviating OTA-induced nephrosis and associated systemic energy metabolism disorders.-Yang, X., Xu, W., Huang, K., Zhang, B., Wang, H., Zhang, X., Gong, L., Luo, Y., He, X. Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity.

Novel reno-protective mechanism of Aspirin involves H2AK119 monoubiquitination and Set7 in preventing type 1 diabetic nephropathy

BACKGROUND

Even after several novel therapeutic approaches, the number of people with diabetic nephropathy (DN) still continues to increase globally, this suggest to find novel therapeutic strategies to prevent it completely. Recent reports, are indicating the ubiquitin proteasome system alterations in DN. Recently, we also showed that, histone H2AK119 mono-ubiquitination (H2AK119-Ub) found to regulate Set7, a key epigenetic enzyme in the development of renal fibrosis under type 1 diabetic condition. Hence, we aimed to study the role of a known 20s proteasome inhibitor Aspirin, on histone ubiquitination in the progression of DN.

METHODS

Male Wistar rats were rendered diabetic using a single dose of Streptozotocin (55mgkg^-1, ip). After 4 weeks, diabetic animals were grouped into respective groups and the drug, aspirin, low dose (25mgkg^-1day^-1), high dose (50mgkg^-1day^-1) was administered through po route. At the end of the study, kidneys from all the groups were collected and processed separately for glomerular isolation, protein isolation, and for histopathological studies.

RESULTS

Aspirin administration, reduced the protein expression of Mysm1, increased the protein expression of H2AK119-Ub and thereby reduced the Set7 protein expression in glomeruli isolated from diabetic animals and prevented renal fibrosis.

CONCLUSIONS

In conclusion, our results are clearly indicating that, aspirin prevents renal fibrosis in diabetic animals through decreasing the expression of Mysm1, increasing the expression of H2AK119-Ub and thereby decreasing the protein expression of Set7, which is a novel mechanism. Moreover, this mechanism may lay down a novel strategy to prevent DN completely in future.

Combination of aspirin with telmisartan suppresses the augmented TGFbeta/smad signaling during the development of streptozotocin-induced type I diabetic nephropathy

Diabetic nephropathy (DN) is the most common indication for the development of end stage renal diseases. Inflammation is increasingly seen as the core process in the development of diabetes. Inflammatory markers e.g. NFkappaB (p65 levels), TNFalpha, COX-2 and TGFbeta-smad signaling are the key elements in the development of DN. Renin-angiotensin system suppressors like telmisartan have been used to treat DN, but they are not able to prevent completely because of development of resistance against them. Anti-inflammatory agents like, aspirin acts through both COX dependent and COX independent pathways. Hence, we thought that combining aspirin with telmisartan will be better therapeutic option in preventing the progression of nephropathy in diabetes. In the present study we studied the effect of this combination on inflammatory markers [COX-2, NFkappaB (p65 levels), TNFalpha], TGFbeta-smad expression in preventing the progression of streptozotocin-induced type I diabetic nephropathy. Treatment of aspirin significantly prevented the progression of nephropathy and inhibited the augmented COX-2, NFkappaB (p65 levels), TNFalpha, and TGFbeta-smad expression. Combination of aspirin with telmisartan resulted in a further decrease in the development of nephropathy and inflammatory markers in comparison to aspirin alone treatment. This is the first report which shows that aspirin in combination with telmisartan is more proficient in the treatment of diabetic nephropathy than any single drug therapy and involves the change in expression of inflammatory markers and TGFbeta-smad signaling.

Aspirin inhibits MMP-9 mRNA expression and release via the PPARalpha/gamma and COX-2/mPGES-1-mediated pathways in macrophages derived from THP-1 cells

In present study, we investigated the effects of aspirin on matrix metalloproteinase (MMP)-9 mRNA expression and release and its possible mechanisms in macrophages derived from THP-1 cells. The macrophages were divided into different groups and treated with different drugs, the mRNA expression of MMP-9, peroxisome proliferator-activated receptor (PPAR) alpha and gamma, cyclooxygenase (COX)-2, membranebound prostaglandin E synthase (mPGES)-1 in macrophages were examined with reverse-transcription polymerase chain reaction, and the protein expressions of PPAR alpha and gamma, mPGES-1 were detected by Western-blot, the levels of MMP-9 and PGE(2) in cultured supernatants were determined with enzyme-linked immunosorbent assay. The results indicated that after the macrophages were incubated with aspirin for 24h, the MMP-9 mRNA expression and release were decreased, while the PPAR alpha/gamma mRNA and protein expression was increased, respectively, and PPAR alpha/gamma agonists could also decrease MMP-9 mRNA expression and release. Additionally, the COX-2 mRNA expression, mPGES-1 mRNA and protein expression in macrophages were all decreased after incubation with aspirin for 24h and the PGE(2) release was also decreased. The macrophages stimulated with PGE(2) for 24h might increase the MMP-9 mRNA expression and release. When PGE(2) plus PPAR alpha agonist or PPAR gamma agonist were simultaneously used, the stimulation of MMP-9 mRNA expression and release by PGE(2) was significantly decreased. It might be concluded that aspirin could inhibit the MMP-9 gene expression and release through the PPARalpha/gamma and COX-2/mPGES-1-mediated pathways and the two pathways might be partly overlapped and even be interrelated.