Expression of transforming growth factor-beta-inducible gene-h3 in normal and cyclosporine-treated rat kidney

Lysyl oxidase inhibitors attenuate cyclosporin A-induced nephropathy in mouse

Calcineurin inhibitors, such as Cyclosporin (CsA), are the mainstay of anti-rejection therapy in solid organ transplants but can paradoxically induce progressive nephropathy characterised by renal dysfunction and interstitial fibrosis. Lysyl oxidases (LOXs), a group of enzymes that catalyse extracellular matrix (ECM) crosslinking, were shown to implicate in tissue scarring. It is hypothesized that inhibition of these enzymes may render therapeutic effects against CsA-induced nephropathy. In this study, 6-to-8 weeks old C57BL/6 J mice were administered saline or CsA (30 mg/kg/day s.c) for 16 weeks. At 8 weeks, CsA-treated animals were divided into 5 groups respectively treated with: (1) vehicle, (2) PXS-5505 (Pan-LOX inhibitor), (3) PXS-5382 (LOX-like 2 inhibitor), (4) PXS-5505 for 4 weeks then PXS-5382 for 4 weeks (sequential therapy), and (5) Telmisartan (standard therapy). Our results indicate that CsA administration significantly increased the levels of blood urea nitrogen, glomerular and tubular injury, tubulointerstitial fibrosis, inflammation and oxidative stress in mouse kidney. These changes were associated with upregulated mRNA expression of LOX and LOXL2. Administration of Pan-LOX or LOXL2 inhibitors or the sequential therapy suppressed the expression of ECM proteins (α-SMA, FN and COL1A), matrix metalloproteases (MMP)2 and 9, inflammatory markers (TNFα and MCP-1) and TGF-β1-Smad3 signalling. Among all regimens including telmisartan, only Pan-LOX inhibitor PXS-5505 was able to attenuate uraemia. Collectively, our study suggests that Pan-LOX and LOXL2 inhibition can attenuate progressive nephropathy due to CsA administration.

Role of Klotho in Chronic Calcineurin Inhibitor Nephropathy

Calcineurin inhibitors (CNIs) are the most popular immunosuppressants in organ transplantation, but nephrotoxicity is a major concern. The common mechanism underlying chronic CNI nephropathy is oxidative stress, and the process of chronic CNI nephropathy is similar to that of aging. Current studies provide evidence that antiaging Klotho protein plays an important role in protecting against oxidative stress, and its signaling is a target for preventing oxidative stress-induced aging process. In this review, we focus on the association between Klotho and oxidative stress and the protective mechanism of action of Klotho against oxidative stress in chronic CNI nephropathy. In addition, we discuss the delivery strategy for Klotho in CNI-induced nephropathy.

Hepatitis C-induced hepatocyte apoptosis following liver transplantation is enhanced by immunosuppressive agents

In recurrent hepatitis C (HCV) post-liver transplantation (OLT), the combination of immunosuppressants and HCV is postulated to increase hepatocyte apoptosis and liver fibrosis. We evaluated hepatocyte apoptosis within the liver tissue of patients with postOLT HCV recurrence compared to HCV-negative individuals and correlated these findings with the effects of immunosuppressants on HCV-induced cell death and its inhibition in primary mouse hepatocytes (PMoH). Liver biopsies from patients with and without HCV were evaluated by immunohistochemistry for markers of apoptosis M30 CytoDEATH (M30) and cleaved PARP (clPARP). PMoH from C57BL/6 mice were infected with recombinant adenoviruses (rAdHCV) that expressed HCV proteins in hepatocytes. Infected cells were treated with cyclosporine, tacrolimus, sirolimus and/or MMF with or without pan-caspase inhibitor Q-VD-Oph. Cell viability and apoptosis were evaluated using crystal violet assays and Western immunoblots probed for cleaved caspase-3 (clCas3) and clPARP. Both M30 and clPARP were increased in the liver biopsies of patients with postOLT HCV recurrence compared to HCV-negative individuals. Treatment of rAdHCV-infected PMoH with cyclosporine, tacrolimus or sirolimus reduced cell viability and increased clCas3 and clPARP compared to rAdHCV infection alone. Addition of MMF to cyclosporine, tacrolimus or sirolimus further reduced cell viability and increased clCas3 and clPARP. Q-VD-Oph improved cell viability in HCV-infected PMoH treated with immunosuppressants alone and in combination and reduced clCas3 and clPARP by approximately 90%. Immunosuppressive agents, especially in combination, enhanced apoptosis in HCV-infected hepatocytes. The finding that Q-VD-Oph reversed hepatocyte death suggests that treatments utilizing apoptosis inhibition might reduce liver injury in postOLT HCV recurrence.

Effect of Immunosuppressive Agents on Hepatocyte Apoptosis Post-Liver Transplantation

INTRODUCTION

Immunosuppressants are used ubiquitously post-liver transplantation to prevent allograft rejection. However their effects on hepatocytes are unknown. Experimental data from non-liver cells indicate that immunosuppressants may promote cell death thereby driving an inflammatory response that promotes fibrosis and raises concerns that a similar effect may occur within the liver. We evaluated apoptosis within the liver tissue of post-liver transplant patients and correlated these findings with in vitro experiments investigating the effects of immunosuppressants on apoptosis in primary hepatocytes.

METHODS

Hepatocyte apoptosis was assessed using immunohistochemistry for M30 CytoDEATH and cleaved PARP in human liver tissue. Primary mouse hepatocytes were treated with various combinations of cyclosporine, tacrolimus, sirolimus, or MMF. Cell viability and apoptosis were evaluated using crystal violet assays and Western immunoblots probed for cleaved PARP and cleaved caspase 3.

RESULTS

Post-liver transplant patients had a 4.9-fold and 1.7-fold increase in M30 CytoDEATH and cleaved PARP compared to normal subjects. Cyclosporine and tacrolimus at therapeutic concentrations did not affect hepatocyte apoptosis, however when they were combined with MMF, cell death was significantly enhanced. Cell viability was reduced by 46% and 41%, cleaved PARP was increased 2.6-fold and 2.2-fold, and cleaved caspase 3 increased 2.2-fold and 1.8-fold following treatment with Cyclosporine/MMF and Tacrolimus/MMF respectively. By contrast, the sirolimus/MMF combination did not significantly reduce hepatocyte viability or promote apoptosis.

CONCLUSION

Commonly used immunosuppressive drug regimens employed after liver transplantation enhance hepatocyte cell death and may thus contribute to the increased liver fibrosis that occurs in a proportion of liver transplant recipients.

Expression of erythropoietin and its receptor in kidneys from normal and cyclosporine-treated rats

Long-term treatment with cyclosporine A (CsA) is associated with various types of complications; however, CsA-induced anemia has not been reported. The present study examined the impact of CsA on hematopoietic parameters and intrarenal expression of erythropoietin (EPO) and the EPO receptor (EPOR) in a rat model of chronic CsA nephrotoxicity. Sprague-Dawley rats were fed a low-salt diet (0.05% sodium) and were treated daily for 4 weeks with vehicle (olive oil 1 mL/kg subcutaneously) or CsA (15 mg/kg subcutaneously). The expression of EPO and EPOR was evaluated by immunohistochemistry and immunoblotting, and hematopoietic parameters were assessed by measuring blood hemoglobin and hematocrit levels, and these variables were compared between treatment groups. Renal function, oxidative stress, histopathology (tubulointerstitial fibrosis), apoptotic cell death, and expression of transforming growth factor β-inducible gene-h3 (βig-h3) were also compared between treatment groups. In kidneys from vehicle-treated rats, endogenous EPO and EPOR protein were expressed constitutively in the outer stripe of the outer medulla and the cortex. EPO protein expression decreased significantly in kidneys from CsA-treated rats. By contrast, EPOR expression was higher in kidneys from CsA-treated rats than in vehicle-treated rats. These changes were accompanied by decreases in serum hemoglobin and hematocrit levels and correlated with the number of cells positive for terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (r = -0.769, P = .003) and βig-h3 protein expression (r = -0.910, P < .001). Long-term treatment with CsA suppresses renal endogenous EPO expression, resulting in anemia. Increases in apoptotic cell death and βig-h3 expression are closely associated with inhibition of EPO expression in chronic CsA nephrotoxicity.

L-carnitine protects against cyclosporine-induced pancreatic and renal injury in rats

BACKGROUND

L-carnitine has protective effects against various types of injury. This study was designed to evaluate the beneficial effects of L-carnitine on pancreatic and renal injuries caused by cyclosporine (CsA).

METHODS

Rats maintained on a low sodium diet were given vehicle (olive oil, 1 mL/kg/d), CsA (15 mg/kg/d), L-carnitine (50 or 200 mg/kg/d), or a combination of CsA and L-carnitine for 4 weeks. The impact of L-carnitine on pancreatic injury was assessed by blood glucose levels, plasma insulin concentrations, and hemoglobulin A1c (HbA1c). In addition, the protective effects of L-carnitine against CsA-induced kidney injury were evaluated in terms of renal function, histopathology (inflammatory cell influx and tubulointerstitial fibrosis), oxidative stress (8-hydroxy 2'-deoxyguanosine, 8-OHdG), transforming growth factor-betal (TGF-β1), apoptosis (caspase-3), and autophagy (LC3-II).

RESULTS

CsA treatment caused diabetes, renal dysfunction, tubulointerstitial inflammation (ED-1-positive cells), and fibrosis, which were accompanied by an increase in 8-OHdG production and upregulation of TGF-β1, caspase-3, and LC3-II. Concomitant administration of L-carnitine increased plasma insulin concentrations, decreasing plasma glucose and HbA1c levels. In the kidney, L-carnitine induced dose-dependent improvement of renal function, inflammation, and fibrosis in parallel with suppression of the expression of TGF-β1 and 8-OHdG. Furthermore, the administration of L-carnitine at a high dose inhibited the expression of caspase-3 and LC3-II.

CONCLUSION

These findings suggest that L-carnitine has a protective effect against CsA-induced pancreatic and renal injuries.

Ginseng treatment attenuates chronic cyclosporine nephropathy via reducing oxidative stress in an experimental mouse model

BACKGROUND

This study was performed to investigate whether ginseng extract has a protective effect in an experimental mouse model of chronic cyclosporine (CsA) nephropathy.

METHODS

Mice were treated with CsA (30 mg/kg/day, subcutaneously) with or without Korean red ginseng extract (KRG) (0.2, 0.4 g/kg/day, orally) on a 0.01% salt diet for 4 weeks. The effect of KRG on CsA-induced renal injury was evaluated by assessing renal function and pathology, mediators of inflammation, tubulointerstitial fibrosis and apoptotic cell death. Using an in vitro model, we also examined the effect of KRG on CsA-treated proximal tubular cells (HK-2). Oxidative stress was measured by assessing 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in 24-hour urine, tissue sections, and culture media.

RESULTS

Four weeks of CsA treatment caused renal dysfunction, typical pathologic lesions and apoptotic cell death. KRG treatment reduced serum creatinine and blood urea nitrogen and histopathology and increased creatinine clearance. Proinflammatory and profibrotic molecules such as induced nitric oxide synthase, cytokines, transforming growth factor (TGF)-β1 and TGF-β1-inducible gene h3 and apoptotic cell death, also decreased with KRG treatment. Consistent with these results, in vitro studies showed that addition of KRG protected against CsA-induced morphological changes, cytotoxicity, inflammation, and apoptotic cell death as demonstrated by annexin V binding. These changes were accompanied by decrease in the level of 8-OHdG in urine and culture supernatant after KRG treatment.

CONCLUSION

The results of our in vivo and in vitro studies demonstrate that KRG has a protective effect in CsA-induced renal injury via reducing oxidative stress.

Enhanced apoptosis in post-liver transplant hepatitis C: Effects of virus and immunosuppressants

Hepatitis C (HCV)-infected patients have a poorer survival post-liver transplantation compared to patients transplanted for other indications, since HCV recurrence post-transplant is universal and commonly follows an aggressive course. There is increasing evidence that in the non-transplant setting, induction of hepatocyte apoptosis is one of the main mechanisms by which HCV drives liver inflammation and fibrosis, and that HCV proteins directly promote apoptosis. Recent studies have shown that post-liver transplant, there is a link between high levels of HCV replication, enhanced hepatocyte apoptosis and the subsequent development of rapidly progressive liver fibrosis. Although the responsible mechanisms remain unclear, it is likely that immunosuppressive drugs play an important role. It is well known that immunosuppressants impair immune control of HCV, thereby allowing increased viral replication. However there is also evidence that immunosuppressants may directly induce apoptosis and this may be facilitated by the presence of high levels of HCV replication. Thus HCV and immunosuppressants may synergistically interact to further enhance apoptosis and drive more rapid fibrosis. These findings suggest that modulation of apoptosis within the liver either by changing immunosuppressive therapy or the use of apoptosis inhibitors may help prevent fibrosis progression in patients with post-transplant HCV disease.

The pathogenesis and treatment of chronic allograft nephropathy

Despite improvements in immunosuppressive therapy, long-term allograft survival after kidney transplantation remains as low as 50%. Chronic allograft nephropathy (CAN) is a major cause of late graft loss in renal transplant recipients. The histopathologic signs of CAN-interstitial fibrosis, tubular atrophy, glomerulopathy and vasculopathy-are nonspecific; therefore, the 2007 Banff classification dispensed with the term CAN in favor of 'interstitial fibrosis and tubular atrophy without evidence of any specific etiology'. In this Review, however, the term CAN is used to describe a clinical syndrome that is characterized by progressive decline in renal function from 3 months after transplantation, accompanied by the development of proteinuria and hypertension. The pathogenesis of CAN is complex and incompletely understood, and involves several immunological and non-immunological factors. We discuss the contributory roles of acute rejection, donor age, anti-human-leukocyte-antigen antibodies, calcineurin inhibitor nephrotoxic effects, viral infection, hypertension and hyperlipidemia. The prevention and treatment of CAN needs multidisciplinary strategies. Early detection by means of protocol biopsy and calculation of glomerular filtration rate is the first step, followed by management of modifiable risk factors.

Established and newly proposed mechanisms of chronic cyclosporine nephropathy

Cyclosporine (CsA) has improved patient and graft survival rates following solid-organ transplantation and has shown significant clinical benefits in the management of autoimmune diseases. However, the clinical use of CsA is often limited by acute or chronic nephropathy, which remains a major problem. Acute nephropathy depends on the dosage of CsA and appears to be caused by a reduction in renal blood flow related to afferent arteriolar vasoconstriction. However, the mechanisms underlying chronic CsA nephropathy are not completely understood. Activation of the intrarenal renin-angiotensin system (RAS), increased release of endothelin-1, dysregulation of nitric oxide (NO) and NO synthase, up-regulation of transforming growth factor-beta1 (TGF-beta1), inappropriate apoptosis, stimulation of inflammatory mediators, enhanced innate immunity, endoplasmic reticulum stress, and autophagy have all been implicated in the pathogenesis of chronic CsA nephropathy. Reducing the CsA dosage or using other renoprotective drugs (angiotensin II receptor antagonist, mycophenolate mofetil, and statins, etc.) may ameliorate chronic CsA-induced renal injury. This review discusses old and new concepts in CsA nephropathy and preventive strategies for this clinical dilemma.

Up-regulated transforming growth factor beta-inducible gene h3 in rheumatoid arthritis mediates adhesion and migration of synoviocytes through alpha v beta3 integrin: Regulation by cytokines

OBJECTIVE

To delineate the expression of transforming growth factor beta-inducible gene h3 (betaIG-H3) in rheumatoid synovitis and to determine the regulatory role of betaIG-H3 in the adhesion and migration of fibroblast-like synoviocytes (FLS).

METHODS

Synovial tissue was obtained from patients with rheumatoid arthritis (RA) during joint replacement surgery, and FLS were isolated using enzymatic treatment. Immunohistochemical staining was performed to show the expression of betaIG-H3 within rheumatoid synovium. Synthesis of betaIG-H3 from FLS was determined by semiquantitative reverse transcription-polymerase chain reaction, Western blot analysis, and enzyme-linked immunosorbent assay. Cell adhesion and migration assays were performed using the YH18 peptide in the fourth fas-1 domain of betaIG-H3 and function-blocking antibodies to integrins.

RESULTS

Expression of betaIG-H3 was up-regulated in RA synovial tissue compared with synovial tissue from patients with osteoarthritis. FLS isolated from RA synovial tissue constitutively produced betaIG-H3, which was up-regulated by transforming growth factor beta1, interleukin-1beta, and tumor necrosis factor alpha. Although FLS expressed a variety of integrins, betaIG-H3 mediated adhesion and migration of FLS through interaction with alpha v beta3 integrin. Cytokines failed to affect the betaIG-H3-mediated adhesion. However, migration of FLS guided by betaIG-H3 was enhanced by interferon-gamma and platelet-derived growth factor type BB. The YH18 peptide in the fourth fas-1 domain of betaIG-H3 inhibited adhesion and migration in a dose-dependent manner.

CONCLUSION

The results suggest that betaIG-H3, which is abundantly expressed in RA synovial tissue, plays a regulatory role in chronic destructive inflammation through the modulation of the adhesion and migration of FLS. This finding indicates the relevance of betaIG-H3 and alpha v beta3 integrin-interacting motifs as potential therapeutic targets in this disease.

Urinary Transforming Growth Factor-β–Induced Gene-h3 (βig-h3) as a Sensitive Predictor in Chronic Cyclosporine Nephrotoxicity

Transforming growth factor (TGF)-beta is involved in the pathogenesis of chronic cyclosporine nephrotoxicity (CyAN). Since the expression of TGF-beta induced gene h3 (betaig-h3) is up-regulated by TGF-beta, we evaluated the potential role of betaig-h3 as a sensitive urinary marker to monitor the progression/regression of chronic CyAN. Urinary betaig-h3 levels were determined using an enzyme-linked immunosorbent assay in nine patients with chronic CyAN and 13 patients with stable graft function. We scored the extent of tubulointerstitial fibrosis (TIF) and using immunoperoxidase labeling, determined betaig-h3 expression in renal tissues of patients with chronic CyAN. Urinary betaig-h3 excretion was higher in chronic CyAN compared to control subjects (173.4+/-26.0 vs 62.6+/-5.0 ng/mg creatinine, P<.01). In chronic CyAN, the degree of TIF correlated with increased urinary betaig-h3 levels (r=.785, P<.05). In kidneys with chronic CyAN, betaig-h3 labeling was more prominent at the basement membranes (BM) of the tubules where inflammatory cells had infiltrated the surrounding interstitium. Moreover, the BM of the atrophied tubules and their surrounding interstitium were strongly labeled. Urinary betaig-h3 levels decreased from 173.4+/-26.0 to 64.9+/-14.4 ng/mg creatinine at 1 month after discontinuation of CyA or reduction in CyA dosage (P<.01) despite unchanged serum creatinine levels. Urinary betaig-h3 levels increased in patients with chronic CyAN and decreased after discontinuation or reduction of CyA dosage. Our results suggested that urinary betaig-h3 levels could be used as a sensitive urinary marker to monitor the progression or regression of chronic CyAN.

Effect of FTY720 on chronic cyclosporine nephropathy in rats

BACKGROUND

Long-term treatment with cyclosporine A (CsA) causes tubulointerstitial inflammation and fibrosis in the kidney. To define the role of lymphocytes in this process, the novel lymphocyte-specific inhibitor FTY720 was administered to rats with experimental model of chronic CsA nephropathy.

METHODS

Sprague-Dawley rats were treated daily for 4 weeks with CsA (7.5 mg/kg), or both CsA and FTY720 (0.125 mg/kg). The effects of FTY720 on CsA-induced renal injury were evaluated using renal function tests and histopathology, and the expression of mediators of CsA-induced renal injury (osteopontin, transforming growth factor-beta1 [TGF-beta1], betaig-h3, and angiotensin II).

RESULTS

FTY720 treatment significantly decreased T-lymphocyte accumulation in kidneys compared with CsA treatment alone. FTY720 treatment improved not only CsA-induced renal dysfunction but also renal histopathology, demonstrated by decreased macrophage infiltration and interstitial fibrosis. Increased osteopontin, TGF-beta1, betaig-h3, and angiotensin II expression in CsA-treated rat kidneys were decreased with FTY720 treatment.

CONCLUSIONS

FTY720 treatment prevents CsA-induced renal injury.

Rosiglitazone protects against cyclosporine-induced pancreatic and renal injury in rats

Rosiglitazone (RGTZ) has protective effect against various types of injury. This study was performed to evaluate the effect of RGTZ on pancreatic and renal injury caused by cyclosporine (CsA). CsA (15 mg/kg) and RGTZ (3 mg/kg) were administered alone and together to the rats for 28 days. The effect of RGTZ on CsA-induced pancreatic injury was evaluated by intraperitoneal glucose tolerance test (IPGTT), plasma insulin concentrations and pancreatic beta-cell morphology. The effect of RGTZ on CsA-induced renal injury was evaluated by assessing renal function and pathology; mediators of inflammation and fibrosis such as angiotensin II (AngII), osteopontin (OPN) and transforming growth factor-beta1 (TGF-beta1) and apoptotic cell death. Four weeks of CsA treatment caused diabetes, renal dysfunction, typical pathologic lesions (arteriolopathy, interstitial fibrosis and inflammatory cells infiltration) and apoptotic cell death. RGTZ treatment decreased blood glucose concentration, increased plasma insulin concentration and preserved pancreatic beta islet mass. RGTZ treatment improved renal function and histopathology. Pro-inflammatory and pro-fibrotic molecules such as AngII, OPN and TGF-beta1, and apoptotic cell death also decreased with RGTZ treatment. These data suggest that RGTZ has a protective effect against CsA-induced pancreatic and renal injury.

A multidisciplinary evaluation of the effectiveness of cyclosporine a in dystrophic mdx mice

Chronic inflammation is a secondary reaction of Duchenne muscular dystrophy and may contribute to disease progression. To examine whether immunosuppressant therapies could benefit dystrophic patients, we analyzed the effects of cyclosporine A (CsA) on a dystrophic mouse model. Mdx mice were treated with 10 mg/kg of CsA for 4 to 8 weeks throughout a period of exercise on treadmill, a protocol that worsens the dystrophic condition. The CsA treatment fully prevented the 60% drop of forelimb strength induced by exercise. A significant amelioration (P < 0.05) was observed in histological profile of CsA-treated gastrocnemius muscle with reductions of nonmuscle area (20%), centronucleated fibers (12%), and degenerating area (50%) compared to untreated exercised mdx mice. Consequently, the percentage of normal fibers increased from 26 to 35% in CsA-treated mice. Decreases in creatine kinase and markers of fibrosis were also observed. By electrophysiological recordings ex vivo, we found that CsA counteracted the decrease in chloride conductance (gCl), a functional index of degeneration in diaphragm and extensor digitorum longus muscle fibers. However, electrophysiology and fura-2 calcium imaging did not show any amelioration of calcium homeostasis in extensor digitorum longus muscle fibers. No significant effect was observed on utrophin levels in diaphragm muscle. Our data show that the CsA treatment significantly normalized many functional, histological, and biochemical endpoints by acting on events that are independent or downstream of calcium homeostasis. The beneficial effect of CsA may involve different targets, reinforcing the usefulness of immunosuppressant drugs in muscular dystrophy.

Attenuation of interstitial inflammation and fibrosis by recombinant human erythropoietin in chronic cyclosporine nephropathy

BACKGROUND

Evidence suggests that recombinant human erythropoietin (rHuEPO) protects neurons and cardiomyocytes from acute insults. We investigated the protective effect of rHuEPO on cyclosporine (CsA)-induced renal injury.

METHODS

CsA (15 mg/kg/day) was given to rats for 1 or 4 weeks, and rHuEPO was concurrently administered at a dose of 100 units/kg (thrice weekly). Effects of rHuEPO on CsA-induced renal injury were evaluated with tubulointerstitial fibrosis (TIF) score, macrophage infiltration, expression of proinflammatory and profibrotic cytokines, and apoptotic cell death.

RESULTS

Administration of rHuEPO decreased TIF score and the number of macrophages, which increased significantly in CsA-treated rat kidneys. At the molecular level, rHuEPO treatment decreased proinflammatory mediators (osteopontin and C-reactive protein) and profibrotic mediators (transforming growth factor-beta1 and transforming growth factor-beta1-inducible gene-h3). Increased apoptotic cell death in CsA-treated rat kidneys was significantly decreased with rHuEPO cotreatment, and apoptosis-related genes were regulated in favor of cell survival (increased Bcl-2 and suppressed caspase-3).

CONCLUSION

rHuEPO has a renoprotective effect against chronic CsA-induced renal injury.