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Recently, we demonstrated that peroxisome proliferator-activated receptor-[alpha] (PPAR[alpha]) ligand ameliorates cisplatin-induced acute renal failure (ARF) by preventing inhibition of substrate oxidation, and also by preventing apoptosis and necrosis of the proximal tubule (Li S, Bhatt R, Megyesi J, Gokden N, Shah SV, and Portilla D. Am J Physiol Renal Physiol 287: F990-F998, 2004). In the following studies, we examined the protective effect of PPAR[alpha] ligand on cisplatin-induced inflammatory responses during ARF. Mice subjected to a single intraperitoneal injection of cisplatin developed ARF at day 3. Cisplatin increased mRNA and protein expression of TNF-[micro] RANTES, and also upregulated endothelial adhesion molecules ICAM-1/VCAM-1 and chemokine receptors CCR1/CCR5. Cisplatin also led to neutrophil infiltration in the corticomedullary region. Pretreatment of wild-type mice with WY-14,643, a fibrate class of PPAR[alpha] ligands, before cisplatin signifcantly suppressed cisplatin-induced upregulation of cytokine/chemokine expression, prevented neutrophil accumulation, and ameliorated renal dysfunction. In contrast, treatment with PPAR[alpha] ligand before cisplatin did not prevent cytokine/chemokine production, neutrophil accumulation, and did not protect kidney function in PPAR[alpha] null mice. In addition, we observed that cisplatin-induced NF-[kappa]B binding activity in nuclear extracts from wild-type mice was markedly reduced by treatment with PPAR[alpha] ligand. These results demonstrate that PPAR[alpha] exerts an anti-inflammatory effect in kidney tissue by a mechanism that includes inhibition of NF-[kappa]B DNA binding activity, and this effect results in inhibition of neutrophil infiltration, cytokine/chemokine release, and amelioration of cisplatin-induced ARF. peroxisome proliferator-activated receptor-[alpha]; inflammation; cisplatin; acute renal failure

PPAR-[alpha] ligand ameliorates acute renal failure by reducing cisplatin-induced increased expression of renal endonuclease G. Am J Physiol Renal Physiol 287: F990-F998, 2004. First published July 27, 2004; doi:10.1152/ajprenal.00206.2004.--Cisplatin injury to the kidney is characterized, in part, by inhibition of substrate oxidation, inflammation, and tubular cell death in the form of apoptosis and necrosis. Recently, we demonstrated that cisplatin-induced inhibition of substrate oxidation can be reversed by the administration of peroxisome proliferator-activated receptor-[alpha] (PPAR-[alpha]) ligands, resulting in amelioration of renal function. We therefore hypothesize that by improving fatty acid oxidation in vivo might protect renal function by reducing both apoptosis and necrosis in cisplatin-treated mice. Mice subjected to a single intraperitoneal injection of cisplatin developed acute renal failure (ARF) at days 3 and 4. At day 4 after cisplatin injection mRNA, protein levels and enzyme activity of proapoptotic renal endonuclease G (Endo G) were increased compared with saline-treated mice. In situ hybridization and immunohistochemical studies localized the increased expression of Endo G mRNA to the cytosolic compartment and Endo G protein to the nuclear compartment of proximal tubules in cisplatin-treated mice. Pretreatment of PPAR-[alpha] wild-type mice with PPAR-[alpha] ligand WY-14643 reduced significantly cisplatin-induced increased protein expression and enzyme activity of Endo G and prevented the nuclear translocation of mitochondrial Endo G. Morphological examination of tubular injury in the PPAR-[alpha] wild-type mice that received PPAR-[alpha] ligand and cisplatin did show significant amelioration of acute tubular necrosis, as well as a significant reduction in the number of apoptotic cells in the proximal tubule when compared with the cisplatin-treated group. In contrast, in PPAR[alpha]-null mice treated with the ligand and cisplatin, Endo G protein expression was not reduced and this was accompanied by lack of protection of kidney function. We conclude that PPAR-[alpha] ligand protects against cisplatin-induced renal injury via a PPAR-[alpha]-dependent mechanism by reducing the expression and enzyme activity of proximal tubule Endo G, which results in amelioration of both proximal tubule cell apoptosis and necrosis. peroxisome proliferator-activated receptor-[alpha]; fatty acid oxidation

Previous studies demonstrate that during cisplatin-induced acute renal failure, there is a significant reduction in proximal tubule fatty acid oxidation. We now report o the effects of peroxisome proliferator-activated receptor-[alpha] (PPAR[alpha]) ligand Wy-14643 (WY) on the abnormalities of medium chain fatty acid oxidation and pyruvate dehydrogenase complex (PDC) activity in kidney tissue of cisplatin-treated mice. Cisplatin causes a significant reduction in mRNA levels and enzyme activity of mitochondrial medium chain acyl-CoA dehydrogenase (MCAD). PPAR[alpha] ligand WY ameliorated cisplatin-induced acute renal failure and prevented cisplatin-induced reduction of mRNA levels and enzyme activity e MCAD. In contrast, in cisplatin-treated PPAR[alpha] null mice, WY did not protect kidney function and did not reverse cisplatin-induced de creased expression of MCAD. Cisplatin inhibited renal PDC activity before the development of acute tubular necrosis, and PDC inhibition was reversed by pretreatment with PPAR[alpha] agonist WY. Cisplatin also induced increased mRNA and protein levels of pyruvate dehydrogenase kinase-4 (PDK4), and PPAR[alpha] ligand WY prevented cisplatin-induced increased expression of PDK4 protein levels in wild-type mice. We conclude that PPAR[alpha] agonists have therapeutic potential for cisplatin-induced acute renal failure. Use of PPAR[alpha] ligand prevents acute tubular necrosis by ameliorating cisplatin-induce inhibition of two distinct metabolic processes, MCAD-mediated fatty acid oxidation and PDC activity. peroxisome proliferator-activated receptor-co pyruvate dehydrogenase complex; fatty acid oxidation

Propagating large amounts of human corneal stromal cells (hCSCs) in vitro while maintaining the physiological quality of their phenotypes is necessary for their application in cell therapy. Here, a novel medium to propagate hCSCs obtained from small incision lenticule extraction (SMILE)‐derived lenticules was investigated and the feasibility of intrastromal injection of these hCSCs was assessed. Primary hCSCs were cultured in porcine corneal stroma extract (pCSE) with RIFA medium including ROCK inhibitor Y27632, insulin‐transferrin‐selenium, fibroblast growth factor 2, L‐ascorbate 2‐phosphate and 0.5% FBS (RIFA medium + pCSE). Protein profiling of the pCSE was identified using nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC‐MS/MS). After subculturing in RIFA medium + pCSE or 10% FBS normal medium (NM), hCSCs at P4 were transplanted into mouse corneal stroma. Compared with NM, ALDH3A1, keratocan and lumican were significantly more expressed in the RIFA medium + pCSE. ALDH3A1 was also more expressed in the RIFA medium + pCSE than in the RIFA medium. Fibronectin and α‐SMA were less expressed in the RIFA medium + pCSE than in the NM. Using Metascape analysis, the pCSE with its anti‐fibrosis, pro‐proliferation and anti‐apoptosis activities, was beneficial for hCSC cultivation. The intrastromally implanted hCSCs in the RIFA medium + pCSE had positive CD34 expression but negative CD45 expression 35 days after injection. We provide a valuable new medium that is advantageous for the proliferation of hCSCs with the properties of physiological keratocytes. Intrastromal injection of hCSCs in RIFA medium + pCSE has the potential for clinical cell therapy. [ABSTRACT FROM AUTHOR]

The novel displaced phase center antenna (DPCA) azimuth multichannel technique is well suited to improve the coarser azimuth resolution of the terrain observation by progressive scans (TOPS) mode for a fixed total receive antenna length. However, both the azimuth multichannel nonuniform sampling and the aliased Doppler spectrum in TOPS raise the azimuth data processing difficulty. This letter proposes an innovative full-aperture processing approach, which adds an azimuth derotation step for each azimuth channel before azimuth multichannel data reconstruction and utilizes the prefiltering operation in the two-step focusing technique to resolve both azimuth ambiguity problems caused by the DPCA technique and azimuth beam progressive scanning. In addition to presenting the proposed azimuth preprocessing approach, the impact of the approach on the azimuth ambiguity-to-signal ratio is analyzed in detail. Simulation results validate the proposed multichannel processing approach for the TOPS mode. [ABSTRACT FROM PUBLISHER]

Cisplatin injury to the kidney is characterized, in part, by inhibition of substrate oxidation, inflammation, and tubular cell death in the form of apoptosis and necrosis. Recently, we demonstrated that cisplatin-induced inhibition of substrate oxidation can be reversed by the administration of peroxisome proliferator-activated receptor-α (PPAR-α) ligands, resulting in amelioration of renal function. We therefore hypothesize that by improving fatty acid oxidation in vivo might protect renal function by reducing both apoptosis and necrosis in cisplatin-treated mice. Mice subjected to a single intraperitoneal injection of cisplatin developed acute renal failure (ARF) at days 3 and 4. At day 4 after cisplatin injection niRNA, protein levels and enzyme activity of proapoptotic renal endonuclease G (Endo G) were increased compared with saline- treated mice. In situ hybridization and immunohistochemical studies localized the increased expression of Endo G mRNA to the cytosolic compartment and Endo G protein to the nuclear compartment of proximal tubules in cisplatin-treated mice-Pretreatment of PPAR-α wild-type mice with PPAR-CE ligand WY-14643 reduced significantly cisplatin-induced increased protein expression and enzyme activity of Endo G and prevented the nuclear translocation of mitochondrial Endo G. Morphological examination of tubular injury in the PPAR-α wild-type mice that received PPAR-α ligand and cisplatin did show significant amelioration of acute tubular necrosis, as well as a significant reduction in the number of apoptotic cells in the proximal tubule when compared with the cisplatin-treated group. In contrast, in PPAR-α-null mice treated with the ligand and cisplatin, Endo G protein expression was not reduced and this was accompanied by lack of protection of kidney function. We conclude that PPAR-α ligand protects against cisplatin-induced renal injury via a PPAR-α-dependent mechanism by reducing the expression and enzyme activity of proximal tubule Endo G, which results in amelioration of both proximal tubule cell apoptosis and necrosis. [ABSTRACT FROM AUTHOR]

The myelin proteolipid protein (Pip) gene encodes the most abundant protein found in mature CNS myelin. Expression of the gene is regulated spatiotemporally, with maximal expression occurring in oligodendrocytes during the myelination period of CNS development. Pip gene expression is tightly controlled. Misregulation of the gene in humans can result in the dysmyelinating disorder Pelizaeus-Merzbacher disease, and in transgenic mice carrying a null mutation or extra copies of the gene can result in a variety of conditions, from late onset demyelination and axonopathy, to severe early onset dysmyelination. In this study we have examined the effects of Pip intron 1 DNA in mediating proper developmental expression of PIp-lacZ fusion genes in transgenic mice. Our results reveal the importance of Pip intron 1 sequences in instigating the expected surge in PIp-lacZ gene activity during (and following) the active myelination period of brain development. Transgene expression was also detected in the testis (Leydig cells), however, the presence or absence of Pip intron 1 sequences had no effect on the temporal profile in the testis. Surprisingly, expression of the transgene missing Pip intron 1 DNA was always higher in the testis, as compared to the brain, in all of the transgenic lines generated. [ABSTRACT FROM AUTHOR]

Our previous studies suggest that peroxisome proliferator-activated receptor-alpha (PPARalpha) plays a critical role in regulating fatty acid beta-oxidation in kidney tissue and this directly correlated with preservation of kidney morphology and function during acute kidney injury. To further study this, we generated transgenic mice expressing PPARalpha in the proximal tubule under the control of the promoter of KAP2 (kidney androgen-regulated protein 2). Segment-specific upregulation of PPARalpha expression by testosterone treatment of female transgenic mice improved kidney function during cisplatin or ischemia-reperfusion-induced acute kidney injury. Ischemia-reperfusion injury or treatment with cisplatin in wild-type mice caused inhibition of fatty-acid oxidation, reduction of mitochondrial genes of oxidative phosphorylation, mitochondrial DNA, fatty-acid metabolism, and the tricarboxylic acid cycle. Similar injury in testosterone-treated transgenic mice resulted in amelioration of these effects. Similarly, there were increases in the levels of 4-hydroxy-2-hexenal-derived lipid peroxidation products in wild-type mice, which were also reduced in the transgenic mice. Similarly, necrosis of the S3 segment was reduced in the two injury models in transgenic mice compared to wild type. Our results suggest proximal tubule PPARalpha activity serves as a metabolic sensor. Its increased expression without the use of an exogenous PPARalpha ligand in the transgenic mice is sufficient to protect kidney function and morphology, and to prevent abnormalities in lipid metabolism associated with acute kidney injury. [ABSTRACT FROM AUTHOR]

Tissue fibrosis is a major cause of death in developed countries. It commonly occurs after either acute or chronic injury and affects diverse organs, including the heart, liver, lung, and kidney. Using the renal ablation model of chronic kidney disease, we previously found that the development of progressive renal fibrosis was dependent on p21(WAF1/Cip1) expression; the genetic knockout of the p21 gene greatly alleviated this disease. In the present study, we expanded on this observation and report that fibrosis induced by two different acute injuries to the kidney is also dependent on p21. In addition, when p21 expression was restricted only to the proximal tubule, fibrosis after injury was induced in the whole organ. One molecular fibrogenic switch we describe is transforming growth factor-β induction, which occurred in vivo and in cultured kidney cells exposed to adenovirus expressing p21. Our data suggests that fibrosis is p21 dependent and that preventing p21 induction after stress could be a novel therapeutic target.

We examined the effects of increased expression of proximal tubule peroxisome proliferator-activated receptor (PPAR)α in a mouse model of renal fibrosis. After 5 days of unilateral ureteral obstruction (UUO), PPARα expression was significantly reduced in kidney tissue of wild-type mice but this downregulation was attenuated in proximal tubules of PPARα transgenic (Tg) mice. When compared with wild-type mice subjected to UUO, PPARα Tg mice had reduced mRNA and protein expression of proximal tubule transforming growth factor (TGF)-β1, with reduced production of extracellular matrix proteins including collagen 1, fibronectin, α-smooth muscle actin, and reduced tubulointerstitial fibrosis. UUO-mediated increased expression of microRNA 21 in kidney tissue was also reduced in PPARα Tg mice. Overexpression of PPARα in cultured proximal tubular cells by adenoviral transduction reduced aristolochic acid-mediated increased production of TGF-β, demonstrating PPARα signaling reduces epithelial TGF-β production. Flow cytometry studies of dissociated whole kidneys demonstrated reduced macrophage infiltration to kidney tissue in PPARα Tg mice after UUO. Increased expression of proinflammatory cytokines including IL-1β, IL-6, and TNF-α in wild-type mice was also significantly reduced in kidney tissue of PPARα Tg mice. In contrast, the expression of anti-inflammatory cytokines IL-10 and arginase-1 was significantly increased in kidney tissue of PPARα Tg mice when compared with wild-type mice subjected to UUO. Our studies demonstrate several mechanisms by which preserved expression of proximal tubule PPARα reduces tubulointerstitial fibrosis and inflammation associated with obstructive uropathy.

Peroxisome proliferator-activated receptor-α (PPARα) activation attenuates cisplatin (CP)-mediated acute kidney injury by increasing fatty acid oxidation, but mechanisms leading to reduced renal triglyceride (TG) accumulation could also contribute. Here, we investigated the effects of PPARα and CP on expression and enzyme activity of kidney lipoprotein lipase (LPL) as well as on expression of angiopoietin protein-like 4 (Angptl4), glycosylphosphatidylinositol-anchored-HDL-binding protein (GPIHBP1), and lipase maturation factor 1 (Lmf1), which are recognized as important proteins that modulate LPL activity. CP caused a 40% reduction in epididymal white adipose tissue (WAT) mass, with a reduction of LPL expression and activity. CP also reduced kidney LPL expression and activity. Angptl4 mRNA levels were increased by ninefold in liver and kidney tissue and by twofold in adipose tissue of CP-treated mice. Western blots of two-dimensional gel electrophoresis identified increased expression of a neutral pI Angptl4 protein in kidney tissue of CP-treated mice. Immunolocalization studies showed reduced staining of LPL and increased staining of Angptl4 primarily in proximal tubules of CP-treated mice. CP also increased TG accumulation in kidney tissue, which was ameliorated by PPARα ligand. In summary, a PPARα ligand ameliorates CP-mediated nephrotoxicity by increasing LPL activity via increased expression of GPHBP1 and Lmf1 and by reducing expression of Angptl4 protein in the proximal tubule.

Previous studies demonstrated that during cisplatin-induced acute renal failure, there is a significant reduction in proximal tubule fatty acid oxidation. We now report on the effects of peroxisome proliferator-activated receptor-alpha (PPAR alpha) ligand Wy-14643 (WY) on the abnormalities of medium chain fatty acid oxidation and pyruvate dehydrogenase complex (PDC) activity in kidney tissue of cisplatin-treated mice. Cisplatin causes a significant reduction in mRNA levels and enzyme activity of mitochondrial medium chain acyl-CoA dehydrogenase (MCAD). PPAR alpha ligand WY ameliorated cisplatin-induced acute renal failure and prevented cisplatin-induced reduction of mRNA levels and enzyme activity of MCAD. In contrast, in cisplatin-treated PPAR alpha null mice, WY did not protect kidney function and did not reverse cisplatin-induced decreased expression of MCAD. Cisplatin inhibited renal PDC activity before the development of acute tubular necrosis, and PDC inhibition was reversed by pretreatment with PPAR alpha agonist WY. Cisplatin also induced increased mRNA and protein levels of pyruvate dehydrogenase kinase-4 (PDK4), and PPAR alpha ligand WY prevented cisplatin-induced increased expression of PDK4 protein levels in wild-type mice. We conclude that PPAR alpha agonists have therapeutic potential for cisplatin-induced acute renal failure. Use of PPAR alpha ligands prevents acute tubular necrosis by ameliorating cisplatin-induced inhibition of two distinct metabolic processes, MCAD-mediated fatty acid oxidation and PDC activity.