The effects of designed angiopoietin-1 variant on lipid droplet diameter, vascular endothelial cell density and metabolic parameters in diabetic db/db mice.

Metabolic syndrome consists of metabolic abnormality with central obesity, hypertriglyceridemia, insulin resistance and hypertension. Adipose tissue has been known as a primary site of insulin resistance and its adipocyte size may be correlated with the degree of insulin resistance. A designed angiopoietin-1, COMP-Angiopoietin-1 (COMP-Ang1), mitigated high-fat diet-induced insulin resistance in skeletal muscle. In this study, we examined effects of COMP-Ang1 on adipocyte droplet size, vascular endothelial cell density in adipose tissue and metabolic parameters in db/db mice by administering COMP-Ang1 or LacZ (as a control) adenovirus. Administration of COMP-Ang1 decreased fat droplet diameter in epididymal and abdominal visceral adipocyte and visceral fat content in db/db mice. The density of vascular endothelial cell in adipose tissue was increased in db/db mice after treatment with COMP-Ang1. Serum resistin and tumor necrosis factor-α level was lower after treatment with COMP-Ang1 in db/db mice. COMP-Ang1 caused a restoration of fasting glycemic control in db/db mice and decreased serum insulin level and insulin resistance measured by HOMA index. These findings indicate that COMP-Ang1 regulates adipocyte fat droplet diameter, vascular endothelial cell density and metabolic parameters in db/db mice.

SIRT1 overexpression decreases cisplatin-induced acetylation of NF-κB p65 subunit and cytotoxicity in renal proximal tubule cells.

As the increased acetylation of p65 is linked to nuclear factor-κB (NF-κB) activation, the regulation of p65 acetylation can be a potential target for the treatment of inflammatory injury. Cisplatin-induced nephrotoxicity is an important issue in chemotherapy of cancer patients. SIRT1, nicotinamide adenine dinucleotide (NAD(+))-dependent protein deacetylase, has been implicated in a variety of cellular processes such as inflammatory injury and the control of multidrug resistance in cancer. However, there is no report on the effect of SIRT1 overexpression on cisplatin-induced acetylation of p65 subunit of NF-κB and cell injury. To investigate the effect of SIRT1 in on cisplatin-induced acetylation of p65 subunit of NF-κB and cell injury, HK2 cells were exposed with SIRT1 overexpression, LacZ adenovirus or dominant negative adenovirus after treatment with cisplatin. While protein expression of SIRT1 was decreased by cisplatin treatment compared with control buffer treatment, acetylation of NF-κB p65 subunit was significantly increased after treatment with cisplatin. Overexpression of SIRT1 ameliorated the increased acetylation of p65 of NF-κB during cisplatin treatment and cisplatin-induced cytotoxicity. Further, treatment of cisplatin-treated HK2 cells with resveratrol, a SIRT1 activator, also decreased acetylation of NF-κB p65 subunit and cisplatin-induced increase of the cell viability in HK2 cells. Our findings suggests that the regulation of acetylation of p65 of NF-κB through SIRT1 can be a possible target to attenuate cisplatin-induced renal cell damage.

Janex-1, a JAK3 inhibitor, ameliorates tumor necrosis factor-α-induced expression of cell adhesion molecules and improves myocardial vascular permeability in endotoxemic mice.

Vascular endothelial cells play an important role in leukocyte trafficking during the inflammatory process. Proinflammatory cytokines activate the expression of cell adhesion molecules in endothelial cells. Janus kinase (JAK) and signal transducer and activator of transcription (STAT) are important intracellular cytokine signaling molecules that are involved in immune responses. The purpose of this study was to investigate the effect of JAK3 inhibition on the expression of tumor necrosis factor (TNF)-α-induced cell adhesion molecules in vascular endothelial cells and to evaluate the therapeutic potential of JAK3 for myocardial vascular permeability in endotoxemic mice. A JAK3 inhibitor, JANEX-1, decreased the TNF-α-induced expression of intercellular adhesion molecule (ICAM)-1, VCAM (vascular cell adhesion molecule)-1 and fractalkine in human umbilical vein endothelial cells (HUVECs). The downregulation of the expression of these cell adhesion molecules by JANEX-1 was mediated via suppression of STAT3 phosphorylation and nuclear factor-κB (NF-κB) activation. In endotoxemic mice, pretreatment with JANEX-1 prevented not only an increase in the cardiac ICAM-1 expression by LPS in the arteriolar and capillary endothelial cells, but also myocardial vascular leakage. These results suggest that inhibition of the JAK/STAT pathway by JANEX-1 ameliorates the expression of TNF-α-induced cell adhesion molecules in HUVECs and improves myocardial vascular permeability.

Erythropoietin induces lymph node lymphangiogenesis and lymph node tumor metastasis.

Cancer therapy often produces anemia, which is treated with erthropoietin (EPO) to stimulate erythrocyte production. However, concerns have recently arisen that EPO treatment may promote later tumor metastasis and mortality. The mechanisms underlying such effects are unknown, but it is clear that EPO has pleiotropic effects in cell types other than hematopoietic cells. In this study, we investigated how EPO affects lymphangiogenesis and lymph node tumor metastasis in mouse models of breast cancer and melanoma. In these models, EPO increased lymph node lymphangiogenesis and lymph node tumor metastasis in a manner associated with increased migration, capillary-like tube formation, and dose- and time-dependent proliferation of human lymphatic endothelial cells. EPO increased sprouting of these cells in a thoracic duct lymphatic ring assay. These effects were abrogated by cotreatment with specific inhibitors of phosphoinositide 3-kinase or mitogen-activated protein kinase, under conditions in which EPO increased Akt and extracellular signal-regulated kinase 1/2 phosphorylation. Intraperitoneal administration of EPO stimulated peritoneal lymphangiogenesis, and systemic treatment of EPO increased infiltration of CD11b(+) macrophages in tumor-draining lymph nodes. Finally, EPO increased VEGF-C expression in lymph node-derived CD11b(+) macrophages as well as in bone marrow-derived macrophages in a dose- and time-dependent manner. Our results establish that EPO exerts a powerful lymphangiogenic function and can drive both lymph node lymphangiogenesis and nodal metastasis in tumor-bearing animals.

SIRT1 activation by resveratrol ameliorates cisplatin-induced renal injury through deacetylation of p53.

Nephrotoxicity is one of the important dose-limiting factors during cisplatin treatment. There is a growing body of evidence that activation of p53 has a critical role in cisplatin-induced renal apoptotic injury. The nicotinamide adenine dinucleotide-dependent protein deacetylase SIRT1 decreases apoptosis through deacetylating of p53, and resveratrol is known as an activator of SIRT1. To study the role of SIRT1 in cisplatin-induced renal injury through interaction with p53, mouse proximal tubular cells (MPT) were treated with cisplatin and examined the expression level of SIRT1, acetylation of p53, PUMA-α, Bax, the cytosolic/mitochondrial cytochrome c ratio, and active caspase-3. The expression of SIRT1 was decreased by cisplatin. Resveratrol, a SIRT1 activator, ameliorated cisplatin-induced acetylation of p53, apoptosis, and cytotoxicity in MPT cells. In addition, resveratrol remarkably blocked cisplatin-induced decrease of Bcl-xL in MPT cells. Further specific SIRT1 inhibition with EX 527 or small interference RNA specific to SIRT1 reversed the effect of resveratrol on cisplatin-induced toxicity. Inhibition of p53 by pifithrin-α reversed the effect of EX527 in protein expression of PUMA-α, Bcl-xL, and caspase-3 and cytotoxicity in MPT cells. SIRT1 protein expression after cisplatin treatment was significantly decreased in the kidney. SIRT1 activation by resveratrol decreased cisplatin-induced apoptosis while improving the glomerular filtration rate. Taken together, our findings suggest that the modulation of p53 by SIRT1 could be a possible target to attenuate cisplatin-induced kidney injury.

Luteolin ameliorates cisplatin-induced acute kidney injury in mice by regulation of p53-dependent renal tubular apoptosis.

BACKGROUND: Cisplatin chemotherapy often causes acute kidney injury in cancer patients. The causative mechanisms of cisplatin-induced acute kidney injury include renal inflammation, activation of p53 tumour suppressor protein and tubular apoptosis. Luteolin, a flavone found in medicinal herbs and plants, has been reported to exhibit anti-inflammatory, antioxidant and anticarcinogenic activities. The purpose of this study was to investigate the anti-apoptotic effect of luteolin on cisplatin-induced acute kidney injury and the molecular mechanism. METHODS: C57BL/6 mice were treated with cisplatin (20 mg/kg) with or without treatment with luteolin (50 mg/kg for 3 days). Renal function, histological changes, degree of oxidative stress and tubular apoptosis were examined. The effects of luteolin on cisplatin-induced expression of renal p53, PUMA-α and Bcl-2 family proteins were evaluated. RESULTS: Treatment of mice with cisplatin resulted in renal damage, showing an increase in blood urea nitrogen and creatinine levels, tubular damage, oxidative stress and apoptosis. Treatment of cisplatin-treated mice with luteolin significantly improved renal dysfunction, reducing tubular cell damage, oxidative stress and apoptosis. Examination of molecules involving apoptosis of the kidney revealed that treatment of cisplatin increased the levels of p53 and its phosphorylation, PUMA-α, Bax and caspase-3 activity that were significantly decreased by treatment with luteolin. CONCLUSION: These results indicate that cisplatin induces acute kidney injury by regulation of p53-dependent renal tubular apoptosis and that luteolin ameliorates the cisplatin-mediated nephrotoxicity through down-regulation of p53-dependent apoptotic pathway in the kidney.

Genistein suppression of TNF-alpha-induced fractalkine expression in endothelial cells.

Genistein is a polyphenolic nonsteroidal isoflavonoid with estrogen-like activity has been shown to have anticancer, antioxidant, and anti-inflammatory activities. Fractalkine is a unique chemokine that functions as a chemoattractant and an adhesion molecule on endothelial cells activated by proinflammatory cytokines. In this study, we investigated the effects of genistein (5-25 muM) on fractalkine expression in human umbilical vein endothelial cells (HUVECs) and on its receptor, CX3CR1, in THP-1 cells in response to treatment with tumor necrosis factor (TNF)- alpha. TNF-alpha significantly induced fractalkine expression in endothelial cells. Genistein decreased TNF-alpha-induced fractalkine expression through suppression of Akt and p38 phosphorylation and NF-kappaB activities. Genistein also strongly suppressed TNF-alpha-induced expression of CX3CR1 in monocytes. Genistein suppressed TNF-alpha-stimulated adhesion of monocytes to HUVECs. Immunohistochemical analysis revealed that genistein suppressed the in vivo lipopolysaccharide (LPS)-induced arterial endothelial fractalkine expression in the heart, kidney, and small intestine. These results suggest that genistein may provide a new pharmacological approach for suppressing fractalkine/CX3CR1-mediated injury under vascular inflammatory conditions.

Epigallocatechin-3-O-gallate decreases tumor necrosis factor-alpha-induced fractalkine expression in endothelial cells by suppressing NF-kappaB.

Epigallocatechin-3-O-gallate (EGCG), the main catechin in green tea, has anti-oxidant, anti-atherosclerotic and anti-inflammatory properties. Fractalkine, a chemokine involved in inflammation and early atherosclerotic processes, acts as a chemoattractant as well as an adhesion molecule in endothelial cells activated by proinflammatory cytokines. In the present study, we investigated the effect of EGCG on fractalkine expression in TNF-alpha-induced human umbilical vein endothelial cells (HUVECs). EGCG decreased TNF-alpha-induced fractalkine mRNA and protein expression in HUVECs in a time-dependent manner. EGCG suppressed the TNF-alpha-induced phosphorylation and degradation of IkappaB-alpha, thereby decreasing the phosphorylation and nuclear translocation of the NF-kappaB p65 subunit in HUVECs. The DNA binding activity of the NF-kappaB p65 subunit was lower in EGCG-pretreated HUVECs than in those treated with TNF-alpha alone. Furthermore, EGCG inhibited monocyte adhesion to HUVECs stimulated by TNF-alpha. The silencing of fractalkine with an siRNA or treatment with a blocking antibody against fractalkine suppressed the TNF-alpha-induced increase in monocyte adhesion. These results demonstrate that EGCG prevents TNF-alpha-induced vascular endothelial fractalkine expression.

COMP-angiopoietin-1 decreases lipopolysaccharide-induced acute kidney injury.

During sepsis endothelial dysfunction is an important pathogenetic mechanism in acute kidney injury (AKI). Lipopolysaccharide (LPS)-induced endotoxemia is associated with renal hemodynamic changes such as alterations of renal blood flow (RBF), vascular resistance, and glomerular filtration rate. We used adenoviral delivery of an engineered variant of native angiopoietin-1 (COMP-angiopoietin-1) containing anti-inflammatory and anti-permeability functions, to determine if regulation of renal endothelial cell dysfunction may have a beneficial role in preventing AKI during LPS-induced endotoxemia in mice. This treatment prevented the endotoxin-induced decrease of RBF and mean arterial pressure while improving glomerular filtration rate. Treatment also mitigated the effects of LPS on renal intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 protein expression, the number of ER-HR3-positive macrophages that infiltrated the kidney, serum nitrate/nitrite levels, renal inducible nitric oxide synthase protein expression, the induction of tubular epithelial reactive oxygen and nitrogen species, and renal microvascular permeability. Our findings show that COMP-angiopoietin-1, an endothelium-oriented therapeutic agent, protects against AKI caused by endotoxemia.

Peritubular capillary preservation with COMP-angiopoietin-1 decreases ischemia-reperfusion-induced acute kidney injury.

Ischemia followed by reperfusion induces microvascular endothelial cell injury, leading to the loss of functions such as regulation of vascular tone, tissue perfusion, permeability, and inflammation in kidney. Improvement of this endothelial dysfunction could be a good approach to treating ischemia-reperfusion-induced renal injury. Cartilage oligomeric matrix protein-angiopoietin-1 (COMP-Ang1) is a variant of native angiogenic factor angiopoietin-1 engineered to have higher activity. We evaluated the protective effect of COMP-Ang1 in an ischemia-reperfusion renal injury model. COMP-Ang1 preserved renal peritubular capillaries after ischemia-reperfusion injury without recruiting pericytes. Pretreatment with COMP-Ang1 attenuated the increase of blood urea nitrogen and serum creatinine levels after ischemia-reperfusion. In addition, the morphological examination indicated less tubular injury in mice pretreated with COMP-Ang1 than in those treated with the vehicle. COMP-Ang1 treatment reduced the increase in the number of Gr-1-positive neutrophils or ER-HR3-positive macrophages infiltrating kidneys, increased phosphorylation of Akt, and preserved renal tissue perfusion flow and microvascular permeability. Furthermore, COMP-Ang1 decreased renal interstitial fibrosis 30 days after the ischemia-reperfusion injury. In conclusion, COMP-Ang1 can be a possible endothelial cell-targeted therapy for preventing ischemia-reperfusion-induced acute kidney injury.

Alpha-lipoic acid attenuates cisplatin-induced acute kidney injury in mice by suppressing renal inflammation.

BACKGROUND: Cisplatin is a chemotherapeutic agent used in treatment of malignant tumours. However, cisplatin produces various side effects, such as nephrotoxicity, neurotoxicity, emetogenesis and ototoxicity. Inflammation is an important mechanism of cisplatin nephrotoxicity. Alpha-lipoic acid (alpha-LA) has anti-inflammatory effects that inhibit both adhesion molecule expression in human endothelial cells and monocyte adhesion by suppressing the nuclear factor-kappaB (NF-kappaB) signalling pathway. The goals of this study were to investigate the anti-inflammatory effects of alpha-LA during cisplatin-induced renal injury and to examine the mechanisms of protection. METHODS: C57BL/6 mice were given cisplatin (20 mg/kg) with or without alpha-LA treatment (100 mg/kg for 3 days). Renal function, histological changes, adhesion molecule expression and inflammatory cell infiltration were examined. The effect of alpha-LA on NF-kappaB activity was evaluated by examining nuclear translocation and phosphorylation of NF-kappaB p65 subunits in kidney tissue. RESULTS: Cisplatin-induced decreases in renal function, measured by blood urea nitrogen, serum creatinine level and renal tubular injury scores, were attenuated by alpha-LA treatment. alpha-LA decreased the tissue levels of tumour necrosis factor-alpha, the expression of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1), and suppressed the infiltration of CD11b-positive macrophages. alpha-LA also attenuated the cisplatin-induced increases in the phosphorylation and nuclear translocation of NF- kappaB p65 subunits in kidney tissue. CONCLUSIONS: These results suggest that alpha-LA treatment ameliorates cisplatin-induced acute kidney injury by reducing inflammatory adhesion molecule expression and NF-kappaB activity.

Mast cells decrease renal fibrosis in unilateral ureteral obstruction.

Mast cells regulate both inflammatory responses and tissue repair in human diseases but there are conflicting reports on the role of these cells in the pathogenesis of various kidney diseases. Here we measured mast cell function in unilateral ureteral obstruction, a well-characterized model of renal fibrosis, using Kit(W)/Kit(W-v) mice genetically deficient in mast cells, wild-type mice, and deficient mice reconstituted by adoptive transfer with mast cells from the wild-type animals. Mast cell-deficient mice had higher levels of renal tubular damage, more stromal fibrosis, higher numbers of infiltrating ERHR3-positive macrophages and CD3-positive T cells, and higher tissue levels of profibrotic transforming growth factor-beta1 than wild-type mice or mice reconstituted by adoptive transfer of mast cells 3 weeks after ureteral obstruction. Similarly, while wild-type and adoptively transferred mice had increased alpha-smooth muscle actin and decreased E-cadherin expression, which are indicators of epithelial-mesenchymal transition, the obstructed kidneys of the mast cell-deficient mice had significant attenuation of those indicators. Thus, our study suggests that mast cells protect the kidney against fibrosis by modulation of inflammatory cell infiltration and by transforming growth factor-beta1-driven epithelial-to-mesenchymal transitions.

Angiopoietin-2 exocytosis is stimulated by sphingosine-1-phosphate in human blood and lymphatic endothelial cells.

OBJECTIVE: Although diverse functions of angiopoietin-2 (Ang2) have been revealed, little is known about upstream signaling molecules regulating Ang2 exocytosis. We therefore investigated the mechanism of Ang2 exocytosis in human blood and lymphatic endothelial cells (BECs and LECs) by stimulation with sphingosine-1-phosphate (S1P). METHODS AND RESULTS: By immunostaining and ELISA analyses using our newly developed human Ang2-specific antibodies, Ang2 exocytosis from human endothelial cells was examined. Both exogenous and endogenous S1P trigger rapid Ang2 exocytosis in time- and dose-dependent manners. Intriguingly, S1P-induced Ang2 exocytosis is higher in LECs than BECs. These effects of S1P are mainly mediated by the endothelial differentiation gene receptor 1, which subsequently activates its downstream phospholipase C and intracellular calcium mobilization to trigger Ang2 exocytosis. Consistently, S1P also dramatically stimulates Ang2 exocytosis from the ECs of ex vivo-incubated blood vessels. CONCLUSION: These results imply that the rapid secretion of Ang2 by exocytosis from endothelial cells is another possible mechanism underlying S1P-induced angiogenesis and inflammation.

Genistein protects the kidney from cisplatin-induced injury.

Oxidative stress and inflammation contribute to the pathogenesis of cisplatin-induced nephrotoxicity. We found that genistein, a tyrosine kinase inhibitor with broad specificities, and which also has estrogen-like activity, had protective effects on cisplatin-induced renal injury in mice. Genistein significantly decreased reactive oxygen species production, the expression of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 proteins, as well as the translocation of the p65 subunit of nuclear factor-kappaB into the nucleus and the infiltration of macrophages, all of which were increased in the kidney by cisplatin treatment. Genistein also decreased cisplatin-induced apoptosis by regulating p53 induction in kidney. Genistein significantly reduced reactive oxygen species production in cisplatin-treated normal human kidney HK-2 cells. These studies show that genistein or similar compounds might be useful in prevention of cisplatin-induced renal injury.

Protective effect of COMP-angiopoietin-1 on cyclosporine-induced renal injury in mice.

BACKGROUND: Peritubular capillary injury induces chronic hypoxia in the renal tubulointerstitium, and renal peritubular capillary dysfunction is an early event that contributes to tubulointerstitial fibrosis. Cyclosporine A (CsA) is a potent immunosuppressant and improves survival of renal allografts. However, the limitation of CsA use is chronic nephrotoxicity. A soluble, stable and potent angiopoietin-1 (Ang1) variant, cartilage oligomeric matrix protein (COMP)-Ang1 has been developed. We investigated whether COMP-Ang1 ameliorates CsA-induced renal injury. METHODS: CsA-treated mice were injected with recombinant adenovirus expressing either COMP-Ang1 or LacZ. Histology, inflammatory, haemodynamic and fibrotic parameters, and signalling pathway were evaluated. RESULTS: Histologic examination showed that COMP-Ang1 significantly decreased CsA-induced tubular damage and tubulointerstitial fibrosis. CsA-induced increases in macrophage infiltration and expression of MCP-1 and ICAM-1 after CsA treatment were significantly reduced by COMP-Ang1. Treatment with COMP-Ang1 also decreased the CsA-induced increases in TGF-beta1 and Smad 2/3 levels while increasing Smad 7 levels. Laser-Doppler sonographic findings and endothelial factor VIII staining revealed that COMP-Ang1 preserved the integrity of peritubular vasculature and intrarenal haemodynamics from the CsA-induced renal injury. COMP-Ang1 inhibited tubular cell apoptosis while increasing tubular cell proliferation in CsA-induced renal injury. CONCLUSIONS: These results indicate that COMP-Ang1 exhibited a protective effect on damaged peritubular capillaries, haemodynamic alteration and inflammation in CsA-induced renal injury. Thus, COMP-Ang1 may be useful as a therapeutic and prophylactic agent for specific protection against endothelial dysfunction and inflammation.

Renoprotective effect of COMP-angiopoietin-1 in db/db mice with type 2 diabetes.

BACKGROUND: Inflammatory processes have been recently seen as underlying the pathogenesis of diabetic nephropathy. Angiopoietin-1 (Ang1) plays essential roles in regulating vascular growth, development, maturation, permeability and inflammation. We have developed a soluble, stable and potent Ang1 variant, cartilage oligomeric matrix protein (COMP)-Ang1. METHODS: In this study, db/db mice were treated with recombinant adenovirus expressing either COMP-Ang1 or LacZ. Histology, inflammatory, metabolic, and fibrotic parameters and signalling pathway were evaluated. RESULTS: COMP-Ang1 reduced albuminuria and decreased mesangial expansion, thickening of the glomerular basement membrane and podocyte foot process broadening and effacement. COMP-Ang1 suppressed both renal expression of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 and monocyte/macrophage infiltration in diabetic db/db mice. COMP-Ang1 also reduced renal tissue levels of transforming growth factor-beta1 (TGF-beta1), alpha-smooth muscle actin, fibronectin, as well as Smad 2/3 expression, but increased Smad 7 expression. In human umbilical vein endothelial cells (HUVECs) grown in high glucose concentrations of glucose, recombinant COMP-Ang1 protein decreased nuclear factor-kappaB (NF-kappaB) expression. COMP-Ang1-mediated inhibition of increased NF-kappaB-DNA binding in nuclear extracts from HUVECs grown in high glucose was significantly blocked by soluble Tie2 receptor-Fc. In addition, COMP-Ang1 significantly decreased fasting blood glucose level, epididymal fat weight to body weight ratio, and epididymal adipocyte size in diabetic db/db mice. After intraperitoneal glucose challenge, COMP-Ang1 significantly lowered plasma glucose levels. However, there was no difference in serum insulin levels. CONCLUSION: We conclude that COMP-Ang1 delayed the fibrotic changes in the kidney of diabetic db/db mice through its anti-inflammatory or metabolic effects.

COMP-angiopoietin-1 ameliorates renal fibrosis in a unilateral ureteral obstruction model.

Injury to the renal microvasculature may be a major factor in the progression of renal disease; therefore, protection of endothelial cells (EC) in renal vasculature may have a therapeutic role in renal fibrosis. Recently, a soluble, stable, and potent angiopoietin-1 (Ang1) variant, cartilage oligomeric matrix protein (COMP)-Ang1, was developed. The contribution of COMP-Ang1 in renal interstitial fibrosis, however, remains to be clarified. This study investigated the effects of COMP-Ang1 on peritubular capillary EC in the renal cortex and the renal fibrogenic process that is triggered by unilateral ureteral obstruction. COMP-Ang1 preserved renal platelet-EC adhesion molecule-1-and Tie2-positive EC. Morphologic examination indicated less tubular injury and tubulointerstitial fibrosis in mice that received COMP-Ang1 than vehicle-treated mice. Interstitial type I collagen and myofibroblast accumulation were significantly suppressed by COMP-Ang1 treatment. COMP-Ang1 increased Tie2 and Akt phosphorylation in ureteral obstructed kidneys. Renal surface microvasculature and renal blood flow were higher after treatment with COMP-Ang1 than with vehicle. COMP-Ang1 treatment decreased monocyte/macrophage infiltration, tissue levels of TGF-beta1, and Smad 2/3 phosphorylation and increased Smad 7 in the obstructed kidney. These results demonstrate that COMP-Ang1 treatment can decrease the progression of renal fibrosis in unilateral ureteral obstruction. COMP-Ang1 may be an endothelium-specific therapeutic modality in fibrotic renal disease.

Protective role of L-2-oxothiazolidine-4-carboxylic acid in cisplatin-induced renal injury.

BACKGROUND: Oxidative stress and inflammation are implicated in the pathogenesis of cisplatin-induced nephrotoxicity. l-2-oxothiazolidine-4-carboxylic acid (OTC) is a cysteine prodrug, and increases cellular glutathione (GSH). OTC is converted to cysteine by the intracellular enzyme, oxoprolinase. To date, the protective role of OTC on cisplatin-induced renal injury has not been investigated. The purpose of the present study was to examine the protective effect of OTC on cisplatin-induced renal injury and to examine the mechanism of its protection. METHODS: Mice were treated with cisplatin with or without administration of OTC. The generation of reactive oxygen species (ROS), expression of intercellular adhesion molecule (ICAM)-1 and monocyte chemoattractant protein (MCP)-1 were determined in the kidney using 2',7'-dichlorofluorescein diacetate, immunostaining or western blot analysis. Nuclear factor (NF)-kappaB activity, infiltration of F4/80-positive cells and apoptosis were also investigated in addition to renal function and histology using electrophoretic mobility shift assay, immunostaining, western blot analysis, uridine triphosphate (dUTP) nick-end labelling or periodic acid-Schiff staining. The effect of OTC on superoxide dismutase activity and GSH level in cisplatin-treated normal adult human kidney (HK-2) cells were measured using assay kits. RESULTS: The administration of OTC resulted in a significant reduction of cisplatin-induced ROS production, the p65 subunit of NF-kappaB translocation into nucleus, expression of ICAM-1, caspase 3 activity, expression of MCP-1 and the infiltration of macrophages into renal tissue. OTC markedly ameliorated renal damage induced by cisplatin through antioxidant and anti-inflammatory effect. CONCLUSIONS: These results suggest that OTC can be a potential therapeutic agent in cisplatin-induced renal injury through decreasing the ROS levels and activation of NF-kappaB.

Rosiglitazone ameliorates cisplatin-induced renal injury in mice.

BACKGROUND: Inflammatory mechanisms may play an important role in the pathogenesis of cisplatin nephrotoxicity. Agonists of the peroxisome proliferator-activated receptor-gamma (PPARgamma), such as rosiglitazone, have been recently demonstrated to regulate inflammation by modulating the production of inflammatory mediators and adhesion molecules. The purpose of this study was to examine the protective effects of rosiglitazone on cisplatin nephrotoxicity and to explore the mechanism of its renoprotection. METHODS: Mice were treated with cisplatin with or without pre-treatment with rosiglitazone. Renal functions, histological findings, aquaporin 2 (AQP2) and adhesion molecule expression, macrophage infiltration and tumour necrosis factor-alpha (TNF-alpha) levels were investigated. The effect of rosiglitazone on nuclear factor (NF)-kappaB activity and on viability was examined using cultured human kidney (HK-2) cells. RESULTS: Rosiglitazone significantly decreased both the damage to renal function and histological pathology after cisplatin injection. Pre-treatment with rosiglitazone reduced the systemic levels of TNF-alpha and down-regulated adhesion molecule expression in addition to the infiltration of inflammatory cells after cisplatin administration. Rosiglitazone restored the decreased AQP2 expression after cisplatin treatment. Pre-treatment with rosiglitazone blocked the phosphorylation of the p65 subunit of NF-kappaB in cultured HK-2 cells. Rosiglitazone had a protective effect via a PPARgamma-dependent pathway in cisplatin-treated HK-2 cells. CONCLUSION: These results showed that pre-treatment with rosiglitazone attenuates cisplatin-induced renal damage through the suppression of TNF-alpha overproduction and NF-kappaB activation.

Resveratrol suppresses tumor necrosis factor-alpha-induced fractalkine expression in endothelial cells.

Up-regulation of fractalkine is involved in vascular and tissue damage in inflammatory conditions. Resveratrol has been shown to have anti-inflammatory, antioxidant, and antitumor activities. Its regulatory effects on expression of fractalkine in vascular endothelial cells and fractalkine receptor CX3CR1 in monocytes have not been studied. We evaluated the effects of resveratrol on fractalkine expression in human umbilical vein endothelial cells and CX3CR1 expression in THP-1 cells in response to treatment with tumor necrosis factor (TNF)-alpha. TNF-alpha significantly induced fractalkine mRNA and protein expression in endothelial cells. Resveratrol strongly suppressed TNF-alpha-induced fractalkine expression in endothelial cells through suppression of nuclear factor-kappaB and Sp1 activities. Resveratrol decreased the number of TNF-alpha-induced fractalkine-positive endothelial cells and CX3CR1-positive cells determined by flow cytometric analysis. Resveratrol suppressed TNF-alpha-stimulated monocytes adhesion to human umbilical vein endothelial cells. Immunohistochemical analysis revealed that resveratrol suppressed TNF-alpha-induced arterial endothelial fractalkine expression in heart, kidney, and intestine and decreased ED-1-positive cell infiltration in intestinal villi. Resveratrol may provide a new pharmacological approach for suppressing fractalkine/CX3CR1-mediated injury in inflammatory conditions.