HGF protects rat mesangial cells from high-glucose-mediated oxidative stress

A recombinant plasmid encoding human hepatocyte growth factor promotes healing of combined radiation-trauma skin injury involved in regulating Nrf2 pathway in mice

Combined radiation-trauma skin injury represents a severe and intractable condition that urgently requires effective therapeutic interventions. In this context, hepatocyte growth factor (HGF), a multifunctional growth factor with regulating cell survival, angiogenesis, anti-inflammation and antioxidation, may be valuable for the treatment of combined radiation-trauma injury. This study investigated the protective effects of a recombinant plasmid encoding human HGF (pHGF) on irradiated human immortalized keratinocytes (HaCaT) cells in vitro, and its capability to promote the healing of combined radiation-trauma injuries in mice. The pHGF radioprotection on irradiated HaCaT cells in vitro was assessed by cell viability, the expression of Nrf2, Bcl-2 and Bax, as well as the secretion of inflammatory cytokines. In vivo therapeutic treatment, the irradiated mice with full-thickness skin wounds received pHGF local injection. The injuries were appraised based on relative wound area, pathology, immunohistochemical detection, terminal deoxynucleotidyl transferase dUTP nick end labelling assay and cytokine content. The transfection of pHGF increased the cell viability and Nrf2 expression in irradiated HaCaT cells. pHGF also significantly upregulated Bcl-2 expression, decreased the Bax/Bcl-2 ratio and inhibited the expression of interleukin-1β and tumor necrosis factor-α in irradiated cells. Local pHGF injection in vivo caused high HGF protein expression and noticeable accelerated healing of combined radiation-trauma injury. Moreover, pHGF administration upregulated Nrf2, vascular endothelial growth factor, Bcl-2 expression, downregulated Bax expression and mitigated inflammatory response. In conclusion, the protective effect of pHGF may be related to inhibiting apoptosis and inflammation involving by upregulating Nrf2. Local pHGF injection distinctly promoted the healing of combined radiation-trauma injury and demonstrates potential as a gene therapy intervention for combined radiation-trauma injury in clinic.

Role of Enzymic Antioxidants in Mediating Oxidative Stress and Contrasting Wound Healing Capabilities in Oral Mucosal/Skin Fibroblasts and Tissues

Unlike skin, oral mucosal wounds are characterized by rapid healing and minimal scarring, attributable to the "enhanced" healing properties of oral mucosal fibroblasts (OMFs). As oxidative stress is increasingly implicated in regulating wound healing outcomes, this study compared oxidative stress biomarker and enzymic antioxidant profiles between patient-matched oral mucosal/skin tissues and OMFs/skin fibroblasts (SFs) to determine whether superior oral mucosal antioxidant capabilities and reduced oxidative stress contributed to these preferential healing properties. Oral mucosa and skin exhibited similar patterns of oxidative protein damage and lipid peroxidation, localized within the lamina propria/dermis and oral/skin epithelia, respectively. SOD1, SOD2, SOD3 and catalase were primarily localized within epithelial tissues overall. However, SOD3 was also widespread within the lamina propria localized to OMFs, vasculature and the extracellular matrix. OMFs were further identified as being more resistant to reactive oxygen species (ROS) generation and oxidative DNA/protein damage than SFs. Despite histological evaluation suggesting that oral mucosa possessed higher SOD3 expression, this was not fully substantiated for all OMFs examined due to inter-patient donor variability. Such findings suggest that enzymic antioxidants have limited roles in mediating privileged wound healing responses in OMFs, implying that other non-enzymic antioxidants could be involved in protecting OMFs from oxidative stress overall.

Cotransplant With Pancreatic Islet Homogenate Improved Survival and Long-Term Efficacy of Islet Transplant in Streptozotocin-Diabetic Rats

OBJECTIVES

Pancreatic islet transplant is suggested as a promising treatment option in diabetes, but the number of viable and functional islets and the long-term efficacy of transplanted islets have not been satisfactory. Islet isolation leads to destruction of the extracellular matrix and loss of trophic support of islets, which reduces their survival and function. Reconstruction of islet microenvironment with biomaterials may preserve islet survival and graft efficacy. Accordingly, we investigated the effects of pancreatic islet homogenate on islet quality and graft outcomes in diabetic rats.

MATERIALS AND METHODS

Islets were isolated from the pancreas of Sprague Dawley rats and were cultured with or without pancreatic islet homogenate. Before transplant, viability, insulin content, and insulin released from cultured islets were assessed. Islets were then transplanted into subcapsular space of diabetic rat kidney. Transplant outcomes were evaluated by plasma glucose and insulin levels, glucose tolerance tests, and stress oxidative markers.

RESULTS

Viability and insulin release in the pancreatic islet homogenate-treated islets were significantly higher than that in the control islets. After transplant of islets, recipient rats with pancreatic islet homogenate showed significant decreases in blood glucose and malondialdehyde levels and increases in superoxide dismutase activity and plasma insulin levels.

CONCLUSIONS

Islet treatment with pancreatic islet homogenate could improve islet survival and transplant function and outcomes. Oxidative stress reduction might be a secondary beneficial effect of improved quality of treated islets.

Cellular crosstalk of glomerular endothelial cells and podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes and is the leading cause of end-stage renal disease (ESRD). Persistent proteinuria is an important feature of DKD, which is caused by the destruction of the glomerular filtration barrier (GFB). Glomerular endothelial cells (GECs) and podocytes are important components of the GFB, and their damage can be observed in the early stages of DKD. Recently, studies have found that crosstalk between cells directly affects DKD progression, which has prospective research significance. However, the pathways involved are complex and largely unexplored. Here, we review the literature on cellular crosstalk of GECs and podocytes in the context of DKD, and highlight specific gaps in the field to propose future research directions. Elucidating the intricates of such complex processes will help to further understand the pathogenesis of DKD and develop better prevention and treatment options.

Bidirectional Enhancement of Cell Proliferation Between Iron Oxide Nanoparticle-Labeled Mesenchymal Stem Cells and Choroid Plexus in a Cell-Based Therapy Model of Ischemic Stroke

PURPOSE

Stem cell therapy for ischemic stroke has shown success in experimental settings, but its translation into clinical practice is challenging. The choroid plexus (CP) plays a regulatory role in neural regeneration. Mesenchymal stem cells (MSCs) promote neurogenesis in the ventricular-subventricular zone. However, it is unclear whether MSCs interact with the CP in brain tissue repair.

METHODS

Rat (r)MSCs were labeled with iron oxide nanoparticles (IONs) and transduced with red fluorescent protein, and then injected into the brain of rats with ischemic stroke and monitored over time by magnetic resonance imaging. The functional recovery of rats was determined by the corner test score, Modified Neurological Severity score, and stroke volume. MSCs and CP were also co-cultured for 14 days, and the medium was analyzed with a cytokine array.

RESULTS

In vivo imaging and histologic analysis revealed that ION-labeled MSCs were mainly located at the injection site and migrated to the infarct area and to the CP. Functional recovery was greater in rats treated with MSCs as compared to those that received mock treatment. Bidirectional enhancement of proliferation in MSCs and CP was observed in the co-culture; moreover, MSCs migrated to the CP. Cytokine analysis revealed elevated levels of proliferation- and adhesion-related cytokines and chemokines in the culture medium. Wikipathway predictions indicated that insulin-like growth factor 1/Akt signaling (WP3675), chemokine signaling pathway (WP2292), and spinal cord injury (WP2432) are involved in the increased proliferation and migration of MSCs co-cultured with the CP.

CONCLUSION

Crosstalk with the CP enhances MSC proliferation and migration in a transwell assay. Moreover, MRI reveals MSC migration towards the CP in an ischemic stroke model. The secreted factors resulting from this interaction have therapeutic potential for promoting functional recovery in the brain after ischemic stroke.

HGF protected against diabetic nephropathy via autophagy-lysosome pathway in podocyte by modulating PI3K/Akt-GSK3β-TFEB axis

Podocyte loss is a detrimental feature and major cause of proteinuria in diabetic nephropathy (DN). Our previous study revealed that hepatocyte growth factor (HGF) prevented high glucose-induced podocyte injury via enhancing autophagy. In the current study, we aimed to assess the role of HGF on podocyte homeostasis in DN and clarify its mechanisms further. Diabetic mice treated with HGF had markedly reduced ratio of kidney weight to body weight, urinary albumin excretion, podocyte loss and matrix expansion compared with that in the non-treated counterpart. Simultaneously, HGF-treated diabetic mice exhibited increased autophagy activity as indicated by the decreased accumulation of sequestosome 1 (SQSTM1/ p62) and increased microtubule-associated proteins 1 light chains 3 (LC3) II/LC3I ratio. These beneficial effects of HGF were blocked by HGF/c-Met inhibitor Crizotinib or phosphatidylinositide 3-kinases (PI3K) inhibitor LY294002. Moreover, HGF treatment obviously prevented inactivation of the protein kinase B (Akt)-glycogen synthase kinase 3 beta (GSK3β)-transcription factor EB (TFEB) axis in high glucose-stimulated podocytes, which was associated with improved lysosome function and autophagy. Accordingly, adenovirus vector encoding constitutively active GSK3β (Ad-GSK3β-S9A) offset whereas small interfering RNA against GSK3β (GSK3β siRNA) recapitulated salutary effects of HGF on lysosome number and autophagy in podocytes. These results suggested that HGF protected against diabetic nephropathy through restoring podocyte autophagy, which at least partially involved PI3K/Akt-GSK3β-TFEB axis-mediated lysosomal function improvement.

Rosiglitazone Suppresses Calcium Oxalate Crystal Binding and Oxalate-Induced Oxidative Stress in Renal Epithelial Cells by Promoting PPAR-γ Activation and Subsequent Regulation of TGF-β1 and HGF Expression

Peroxisome proliferator-activated receptor- (PPAR-) γ is a ligand-dependent transcription factor, and it has become evident that PPAR-γ agonists have renoprotective effects, but their influence and mechanism during the development of calcium oxalate (CaOx) nephrolithiasis remain unknown. Rosiglitazone (RSG) was used as a representative PPAR-γ agonist in our experiments. The expression of transforming growth factor-β1 (TGF-β1), hepatocyte growth factor (HGF), c-Met, p-Met, PPAR-γ, p-PPAR-γ (Ser112), Smad2, Smad3, pSmad2/3, and Smad7 was examined in oxalate-treated Madin-Darby canine kidney (MDCK) cells and a stone-forming rat model. A CCK-8 assay was used to evaluate the effects of RSG on cell viability. In addition, intracellular reactive oxygen species (ROS) levels were monitored, and lipid peroxidation in renal tissue was detected according to superoxide dismutase and malondialdehyde levels. Moreover, the location and extent of CaOx crystal deposition were evaluated by Pizzolato staining. Our results showed that, both in vitro and in vivo, oxalate impaired PPAR-γ expression and phosphorylation, and then accumulative ROS production was observed, accompanied by enhanced TGF-β1 and reduced HGF. These phenomena could be reversed by the addition of RSG. RSG also promoted cell viability and proliferation and decreased oxidative stress damage and CaOx crystal deposition. However, these protective effects of RSG were abrogated by the PPAR-γ-specific inhibitor GW9662. Our results revealed that the reduction of PPAR-γ activity played a critical role in oxalate-induced ROS damage and CaOx stone formation. RSG can regulate TGF-β1 and HGF/c-Met through PPAR-γ to exert antioxidant effects against hyperoxaluria and alleviate crystal deposition. Therefore, PPAR-γ agonists may be expected to be a novel therapy for nephrolithiasis, and this effect is related to PPAR-γ-dependent suppression of oxidative stress.

HGF/C-MET PATHWAY HAS A ROLE IN TESTICULAR DAMAGE IN DIABETES INDUCED BY STREPTOZOTOCIN

Objective

The aim of the study was to investigate the role of Hepatocyte Growth Factor (HGF)/c-Met pathway in testicular damage provoked by streptozotocin (STZ)- induced diabetes and the effects of insulin treatment on the HGF/c-Met pathway.

Methods

Total 21 paraffin-embedded testicular tissues of control (n=7), streptozotocin (STZ)-induced diabetic (n=7) and insulin-treated diabetic (n=7) Wistar albino rats were used in this study. Testicular damage was examined histologically and by Johnsen's score was also evaluated. Immunohistochemical stainings of HGF and c-Met were analysed by using antibodies against HGF and c-Met.

Results

We found the degeneration in seminiferous tubule epithelium and disorganization of spermatogenetic cell series in testis tissues of diabetic rats. We also determined decrease both in seminiferous tubule diameter and Johnsen's scores in diabetic group. The expressions of HGF and c-Met in seminiferous tubule epithelium and in spermatogenic cells (especially spermatocytes and spermatids) were significantly increased in diabetic rats compared to those of control. Insulin treatment significantly reduced the diabetes-induced morphological changes and HGF/c-Met over expressions in the diabetic rat testis.

Conclusion

HGF/c-Met pathway might have a role in diabetes- induced testicular damage. Drugs acting on this pathway might be effective to prevent or delay the testicular damage induced by diabetes.

Therapeutic Potential of HGF-Expressing Human Umbilical Cord Mesenchymal Stem Cells in Mice with Acute Liver Failure

Human umbilical cord-derived mesenchymal stem cells (UCMSCs) are particularly attractive cells for cellular and gene therapy in acute liver failure (ALF). However, the efficacy of this cell therapy in animal studies needs to be significantly improved before it can be translated into clinics. In this study, we investigated the therapeutic potential of UCMSCs that overexpress hepatocyte growth factor (HGF) in an acetaminophen-induced acute liver failure mouse model. We found that the HGF-UCMSC cell therapy protected animals from acute liver failure by reducing liver damage and prolonging animal survival. The therapeutic effect of HGF-UCMSCs was associated with the increment in serum glutathione (GSH) and hepatic enzymes that maintain redox homeostasis, including γ-glutamylcysteine synthetase (γ-GCS), superoxide dismutase (SOD), and catalase (CAT). Immunohistochemical staining confirmed that HGF-UCMSCs were mobilized to the injured areas of the liver. Additionally, HGF-UCMSCs modulated apoptosis by upregulating the antiapoptotic Bcl2 and downregulating proapoptotic genes, including Bax and TNFα. Taken together, these data suggest that ectopic expression of HGF in UCMSCs protects animals from acetaminophen-induced acute liver failure through antiapoptosis and antioxidation mechanisms.

Recombinant human hepatocyte growth factor (HGF), but not rat HGF, elicits glomerular injury and albuminuria in normal rats via an immune complex-dependent mechanism

1. Hepatocyte growth factor (HGF) has the therapeutic potential to improve renal fibrosis and proteinuria in rodents with chronic kidney disease. In contrast, long-term administration of human HGF to normal rats reportedly elicits proteinuria. Thus, the role of HGF during proteinuria remains contentious. The aim of the present study was to demonstrate that human HGF is antigenic to rodents and that immune complex formation causes proteinuria. 2. We administered either human or rat HGF to normal rats for 28 days. Albuminuria was evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The renal phenotypes of the two HGF treatments were examined using histological techniques. 3. Administration of human HGF (1 mg/kg per day, i.v.) to rats led to severe albuminuria and glomerular hypertrophy in association with increased blood levels of anti-human HGF IgG and IgG deposition in mesangial areas. Furthermore, an immune complex between human HGF and anti-human HGF IgG stimulated the production of proteinuric cytokines (including transforming growth factor-β) in rat cultured mesangial cells. In contrast, treatment of healthy rats with rat HGF for 4 weeks caused neither mesangial IgG deposition nor elevated anti-HGF IgG in the blood. Overall, rat HGF did not provoke albuminuria. 4. We conclude that human HGF produces pseudotoxic effects in normal rat kidneys via an immune complex-mediated pathway, whereas syngenic HGF is safe due to less deposition of glomerular IgG. Our results affirm the safety of the repeated use of syngenic HGF for the treatment of chronic organ diseases, such as renal fibrosis and liver cirrhosis.

Protective effects of hydroxysafflor yellow A (HSYA) on alcohol-induced liver injury in rats

Hydroxysafflor yellow A (HSYA), the main active natural constituent extracted from Carthamus tinctorius L., has been widely used for the treatment of cerebrovascular and cardiovascular diseases. The aim of this study is to explore the effect of HSYA on alcohol-induced liver injury and the underlying mechanism. Male Sprague-Dawley rats were used to establish the liver injury model induced by alcohol. HSYA treatment ameliorated serum biochemical indicators by reducing the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronan (HA), laminin (LN), and type III precollagen (III-C) in rats. HSYA efficiently increased the activity and messenger RNA (mRNA) of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in rat liver tissue compared with those of model group, which was obviously reduced by alcohol. HSYA also apparently decreased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in rat liver tissue compared with those of model group, which was obviously enhanced by alcohol. Histological studies demonstrated that HSYA substantially reduced the number of macro- and micro-vesicular steatosis, suppressed hepatic fibrogenesis and shrunk ballooning degeneration areas, ameliorated the severity of liver damage induced by long-term drinking, and finally improved the liver architecture. In addition, immunohistochemistry study indicated that the activation of transforming growth factor β1 (TGF-β1) stimulated by alcohol in rat liver tissue was significantly blocked by HSYA. Collectively, these data demonstrated that HSYA can effectively protect the liver of rats from long-term alcohol injury, which relates with the enhanced antioxidant capacity of liver tissues and inhibition of TGF-β1 expression.

L-malate enhances the gene expression of carried proteins and antioxidant enzymes in liver of aged rats

Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. To investigate the antioxidant mechanism of L-malate in the mitochondria, we analyzed the change in gene expression of two malate-aspartate shuttle (MAS)-related carried proteins (AGC, aspartate/glutamate carrier and OMC, oxoglutarate/malate carrier) in the inner mitochondrial membrane, and three antioxidant enzymes (CAT, SOD, and GSH-Px) in the mitochondria. The changes in gene expression of these proteins and enzymes were examined by real-time RT-PCR in the heart and liver of aged rats treated with L-malate. L-malate was orally administered in rats continuously for 30 days using a feeding atraumatic needle. We found that the gene expression of OMC and GSH-Px mRNA in the liver increased by 39 % and 38 %, respectively, in the 0.630 g/kg L-malate treatment group than that in the control group. The expression levels of SOD mRNA in the liver increased by 39 %, 56 %, and 78 % in the 0.105, 0.210, and 0.630 g/kg L-malate treatment groups, respectively. No difference were observed in the expression levels of AGC, OMC, CAT, SOD, and GSH-Px mRNAs in the heart of rats between the L-malate treatment and control groups. These results predicted that L-malate may increase the antioxidant capacity of mitochondria by enhancing the expression of mRNAs involved in the MAS and the antioxidant enzymes.

Mouse hepatic oval cells require Met-dependent PI3K to impair TGF-β-induced oxidative stress and apoptosis

We have previously shown that oval cells harboring a genetically inactivated Met tyrosine kinase (Met^−/− oval cells) are more sensitive to TGF-β-induced apoptosis than cells expressing a functional Met (Met^flx/flx), demonstrating that the HGF/Met axis plays a pivotal role in oval cell survival. Here, we have examined the mechanism behind this effect and have found that TGF-β induced a mitochondria-dependent apoptotic cell death in Met^flx/flx and Met^−/− oval cells, associated with a marked increase in levels of the BH3-only proteins Bim and Bmf. Bmf plays a key role during TGF-β-mediated apoptosis since knocking down of BMF significantly diminished the apoptotic response in Met^−/− oval cells. TGF-β also induced oxidative stress accompanied by NADPH oxidase 4 (Nox4) mRNA up-regulation and decreased protein levels of antioxidant enzymes. Antioxidants inhibit both TGF-β-induced caspase 3 activity and Bmf up-regulation, revealing an oxidative stress-dependent Bmf regulation by TGF-β. Notably, oxidative stress-related events were strongly amplified in Met^−/− oval cells, emphasizing the critical role of Met in promoting survival. Pharmacological inhibition of PI3K did impair HGF-driven protection from TGF-β-induced apoptosis and increased sensitivity of Met^flx/flx oval cells to TGF-ß by enhancing oxidative stress, reaching apoptotic indices similar to those obtained in Met^−/− oval cells. Interestingly, both PI3K inhibition and/or knockdown itself resulted in caspase-3 activation and loss of viability in Met^flx/flx oval cells, whereas no effect was observed in Met^−/− oval cells. Altogether, results presented here provide solid evidences that both paracrine and autocrine HGF/Met signaling requires PI3K to promote mouse hepatic oval cell survival against TGF-β-induced oxidative stress and apoptosis.

Differential effects of low-dose fenofibrate treatment in diabetic rats with early onset nephropathy and established nephropathy

We have previously shown that low-dose fenofibrate treatment has an ability to prevent diabetes-induced nephropathy in rats. We investigated here the comparative pre- and post-treatment effects of low-dose fenofibrate (30 mg/kg/day p.o.) in diabetes-induced onset of nephropathy. Rats were made diabetics by single administration of streptozotocin (STZ, 55 mg/kg i.p.). The development of diabetic nephropathy was assessed biochemically and histologically. Moreover, lipid profile and renal oxidative stress were assessed. Diabetic rats after 8 weeks of STZ-administration developed apparent nephropathy by elevating serum creatinine, blood urea nitrogen and microproteinuria, and inducing glomerular-capsular wall distortion, mesangial expansion and tubular damage and renal oxidative stress. Fenofibrate (30 mg/kg/day p.o., 4 weeks) pretreatment (4 weeks after STZ-administration) markedly prevented diabetes-induced onset of diabetic nephropathy, while the fenofibrate (30 mg/kg/day p.o., 4 weeks) post-treatment (8 weeks after STZ-administration) was less-effective. However, both pre-and post fenofibrate treatments were effective in preventing diabetes-induced renal oxidative stress and lipid alteration in diabetic rats though the pretreatment was slightly more effective. Conversely, both pre-and post fenofibrate treatments did not alter elevated glucose levels in diabetic rats. It may be concluded that diabetes-induced oxidative stress and lipid alteration, in addition to a marked glucose elevation, play a detrimental role in the onset of nephropathy in diabetic rats. The pretreatment with low-dose fenofibrate might be a potential therapeutic approach in preventing the onset of nephropathy in diabetic subjects under the risk of renal disease induction. However, low-dose fenofibrate treatment might not be effective in treating the established nephropathy in diabetic subjects.

Overexpression of HGF transgene attenuates renal inflammatory mediators, Na(+)-ATPase activity and hypertension in spontaneously hypertensive rats

Renal inflammation and oxidative stress are constantly present in experimental hypertension. Since the spontaneously hypertensive rat (SHR) has reduced levels of hepatocyte growth factor (HGF), which suppresses the activation of the proinflammatory nuclear transcription factor kappa B (NF-κB), we speculated that HGF deficiency could play a key role in the pathogenesis of hypertension in the SHR. To test this hypothesis we increased HGF in the SHR by HGF gene delivery. We found that kidneys of 15-week-old SHR had an important reduction in HGF mRNA and protein expression. Adult SHRs were randomly assigned to receive weekly hydrodynamic injection (1mg/kg) of a naked plasmid containing human HGF (hHGF) gene associated with a cytomegalovirus promoter (pCMV-HGF) or empty vector (pcDNA3.1) during 6weeks. WKY rats treated with pcDNA3.1 and pCMV-HGF served as controls. The kidneys in the hypertensive SHR untreated and treated with the empty vector had increased NF-κB activation, elevated mRNA and protein expression of RANTES, MCP-1 and IL-6 and increased oxidative stress. Activity of Na(+)-ATPase was increased while activity of Na(+), K(+)-ATPase was normal. hHGF gene therapy normalized renal NF-κB activity, proinflammatory cytokines, antioxidant status (GSH, SOD and CAT), Na(+)-ATPase activity, reduced renal injury and ameliorated hypertension. Our results suggest that reduction in HGF production plays a major role in the pathogenesis of hypertension in the SHR and increasing HGF is a potential therapeutic target in the treatment of hypertension.

Life-sparing effect of human cord blood-mesenchymal stem cells in experimental acute kidney injury

In search for new sources of mesenchymal stem cells (MSCs) for renal repair in acute kidney injury (AKI), we investigated the potential of human cord blood (CB)-MSCs to cure mice with AKI. Infusion of CB-MSCs in immunodeficient mice with cisplatin-induced AKI ameliorated both renal function and tubular cell injury, and prolonged survival. Transplanted CB-MSCs localized in peritubular areas, limited capillary alterations and neutrophil infiltration. Apoptosis reduced and tubular cell proliferation increased by virtue of stem cell capacity to produce growth factors. The reno-protective effect of CB-MSCs was further confirmed by their ability to inhibit oxidative damage and to induce the prosurvival factor Akt in tubular cells. The evidence that CB-MSCs in vitro increased the production of growth factors and inhibited IL-1 beta and TNFalpha synthesis when cocultured with damaged proximal tubular cells indicates a regenerative and anti-inflammatory action of stem cell treatment. Altogether these results highlight the potential of human CB-MSCs as future cell therapy for testing in human AKI.

Identification of ATP citrate lyase as a positive regulator of glycolytic function in glioblastomas

Glioblastomas, the most malignant type of glioma, are more glycolytic than normal brain tissue. Robust migration of glioblastoma cells has been previously demonstrated under glycolytic conditions and their pseudopodia contain increased glycolytic and decreased mitochondrial enzymes. Glycolysis is suppressed by metabolic acids, including citric acid which is excluded from mitochondria during hypoxia. We postulated that glioma cells maintain glycolysis by regulating metabolic acids, especially in their pseudopodia. The enzyme that breaks down cytosolic citric acid is ATP citrate lyase (ACLY). Our identification of increased ACLY in pseudopodia of U87 glioblastoma cells on 1D gels and immunoblots prompted investigation of ACLY gene expression in gliomas for survival data and correlation with expression of ENO1, that encodes enolase 1. Queries of the NIH's REMBRANDT brain tumor database based on Affymetrix data indicated that decreased survival correlated with increased gene expression of ACLY in gliomas. Queries of gliomas and glioblastomas found an association of upregulated ACLY and ENO1 expression by chi square for all probe sets (reporters) combined and correlation for numbers of probe sets indicating shared upregulation of these genes. Real-time quantitative PCR confirmed correlation between ACLY and ENO1 in 21 glioblastomas (p < 0.001). Inhibition of ACLY with hydroxycitrate suppressed (p < 0.05) in vitro glioblastoma cell migration, clonogenicity and brain invasion under glycolytic conditions and enhanced the suppressive effects of a Met inhibitor on cell migration. In summary, gene expression data, proteomics and functional assays support ACLY as a positive regulator of glycolysis in glioblastomas.

Hepatocyte growth factor/activin A/follistatin system activation during hemodialysis with different low molecular weight heparins

Hepatocyte growth factor (HGF), activin A (Act A), and follistatin (FS) compose an organotrophic system; interestingly it is modified by heparin. To understand if LMWHs (considered distinct drugs) have different clinical profiles regarding the above growth factors, we studied the effects of enoxaparin, nadroparin, and dalteparin on their plasma levels. Seventeen chronic HD patients completed this prospective, crossover trial. They were randomized into six groups: each patient was administered enoxaparin (effective dose of 0.75 mg/kg), nadroparin (70.4 IU/kg) and dalteparin (78.6 IU/kg) in three time periods of two months each. At the end of this period, the cytokine's plasma levels were measured by immunoassays at the start and at 10 min and 180 min of the HD procedure. At 10 min, we observed a striking increase in plasma HGF (32-fold), Act A (4-fold), and FS (53%), all p = 0.0003. The levels of HGF and Act A remained markedly elevated after 180 min (by 295% and 87%, respectively; both p < 0.002), while those of FS returned to baseline. There were no differences in cytokine profile comparing both their peak concentrations and the areas under the curve. Enoxaparin, dalteparin, and nadroparin are seemingly not different considering the release of HGF/Act A/FS during HD procedures; this may reflect their similar profile in other aspects. Moreover, the concentrations of HGF/Act A/FS are close to therapeutic ones, which may partly explain the mechanisms underlying some of the emerging extra-anticoagulant effects of LMWHs.

Tumor necrosis factor-α induces the apoptosis of hepatic stem cells by altering multiple signaling pathways

AIM: To investigate the apoptosis-inducing effect of tumor necrosis factor-α (TNF-α) on hepatic stem cells (WB cells) and to elucidate the molecular mechanisms involved.

METHODS: After WB cells were incubated with TNF-α for different durations, cell apoptosis and cell cycle alterations were analyzed by flow cytometry; DNA alterations were tested by agarose gel electrophoresis; and signaling molecules related to cell proliferation and apoptosis were analyzed by Western blot and electrophoretic mobility shift assay (EMSA).

RESULTS: After treatment with TNF-α for 24 h, apoptosis was induced in 51% of WB cells, and the DNA was broken down into 180-200 bp fragments. Of all growth or apoptosis regulatory proteins examined, the levels of caspase-3 and activated NF-κB were found to be up-regulated after TNF-α treatment. Furthermore, TNF-α treatment could also induce Erk/Akt hypophosphorylation.

CONCLUSION: TNF-α induces growth inhibition and apoptosis of WB cells perhaps by up-regulating caspase-3 and activated NF-κB and inducing Erk/Akt hypophosphorylation.

Hepatocyte growth factor protects hepatocytes against oxidative injury induced by ethanol metabolism

Hepatocyte growth factor (HGF) is involved in many cellular responses, such as mitogenesis and apoptosis protection; however, its effect against oxidative injury induced by ethanol metabolism is not well understood. The aim of this work was to address the mechanism of HGF-induced protection against ethanol-generated oxidative stress damage in the human cell line VL-17A (cytochrome P450 2E1/alcohol dehydrogenase-transfected HepG2 cells). Cells were pretreated with 50 ng/ml HGF for 12 h and then treated with 100 mM ethanol for 0-48 h. Some parameters of oxidative damage were evaluated. We found that ethanol induced peroxide formation (3.3-fold) and oxidative damage as judged by lipid peroxidation (5.4-fold). Damage was prevented by HGF. To address the mechanisms of HGF-induced protection we investigated the cellular antioxidant system. We found that HGF increased the GSH/GSSG ratio, as well as SOD1, catalase, and gamma-glutamylcysteine synthetase expression. To explore the signaling pathways involved in this process, VL-17A cells were pretreated with inhibitors against PI3K, Akt, and NF-kappaB. We found that all treatments decreased the expression of the antioxidant enzymes, thus abrogating the HGF-induced protection against oxidative stress. Our results demonstrate that HGF protects cells from the oxidative damage induced by ethanol metabolism by a mechanism driven by NF-kappaB and PI3K/Akt signaling.

High glucose-induced changes in steroid production in adrenal cells

BACKGROUND

Increased activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in enhanced adrenocorticotropin (ACTH) and serum glucocorticoid levels, has been described in patients with diabetes mellitus and in animal models of this disease; however, altered steroid production by adrenocortical cells could result from local changes triggered by increased reactive oxygen species (ROS), induced in turn by chronic hyperglycaemia. Experiments were designed (1) to analyse the effects of incubating murine adrenocortical cells in hyperglycaemic media on the generation of oxidative stress, on steroid synthesis and on its modulation by the activity of haeme oxygenase (HO); and (2) to evaluate the effect of antioxidant treatment on these parameters.

METHODS

Y1 cells were incubated for 7 days with either normal or high glucose (HG, 30 mmol/L) concentrations, with or without antioxidant treatment. Parameters of oxidative stress and expression levels of haeme oxygenase-1 (HO-1), nitrite levels, L-arginine uptake and progesterone production were determined.

RESULTS

HG augmented ROS and lipoperoxide production, decreasing glutathione (GSH) levels and increasing antioxidant enzymes and HO-1 expression. Basal progesterone production was reduced, while a higher response to ACTH was observed in HG-treated cells. The increase in HO-1 expression and the effects on basal steroid production were abolished by antioxidant treatment. Inhibition of HO activity increased basal and ACTH-stimulated steroid release. Similar results were obtained by HO-1 gene silencing while the opposite effect was observed in Y1 cells overexpressing HO-1.

CONCLUSIONS

HG induces oxidative stress and affects steroid production in adrenal cells; the involvement of HO activity in the modulation of steroidogenesis in Y1 cells is postulated.

Hepatocyte Growth Factor, but not Vascular Endothelial Growth Factor, Attenuates Angiotensin II–Induced Endothelial Progenitor Cell Senescence

Although both hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) are potent angiogenic growth factors in animal models of ischemia, their characteristics are not the same in animal experiments and clinical trials. To elucidate the discrepancy between HGF and VEGF, we compared the effects of HGF and VEGF on endothelial progenitor cells under angiotensin II stimulation, which is a well-known risk factor for atherosclerosis. Here, we demonstrated that HGF, but not VEGF, attenuated angiotensin II–induced senescence of endothelial progenitor cells through a reduction of oxidative stress by inhibition of the phosphatidylinositol-3,4,5-triphosphate/rac1 pathway. Potent induction of neovascularization of endothelial progenitor cells by HGF, but not VEGF, under angiotensin II was also confirmed by in vivo experiments using several models, including HGF transgenic mice.

Hepatocyte growth factor improves viability after H2O2-induced toxicity in bile duct epithelial cells

Intracellular defence mechanisms against oxidative stress may play an important role in the progression of liver diseases, including cholangiopathies. The multifunctional anti-apoptotic hepatocyte growth factor (HGF) has been suggested to have antioxidant functions. The effect of HGF upon cell viability, the generation of ROS, the expression of genes that play a role in ROS defence, and the activation of caspase-3 were measured in bile duct epithelial (BDE) cells in the presence or absence of H(2)O(2). HGF reduced H(2)O(2)-induced loss of viability, diminished H(2)O(2)-mediated ROS generation and abrogated H(2)O(2)-triggered changes in GSH/GSSG ratio. Furthermore, HGF increased the gene-expression of gamma-glutamylcysteine synthetase (GCLC) and glutathione reductase (GSR), while no effect was seen upon the gene-expression of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione peroxidase (GPX1), and glutathione synthetase (GSR). Finally, HGF diminished the proteolytical activation of the key mediator of apoptosis (caspase-3) after H(2)O(2) exposure. Together, HGF may improve viability in bile duct epithelia cells after H(2)O(2) induced toxicity by proliferation, strengthening the intrinsic antioxidant defences, and/or by an attenuation of apoptosis. These in vitro results support the evaluation of HGF as antioxidative factor in hepatobiliary pathologies.

Beneficial effects of spironolactone on glomerular injury in streptozotocin-induced diabetic rats

INTRODUCTION

To investigate the beneficial effects of spironolactone (SPL) on glomerular injury in streptozotocin (STZ)-induced diabetic rats and the possible mechanism.

METHODS AND RESULTS

STZ-induced diabetic rats were divided into control group, STZ group, and SPL group. Glomerular morphology was observed by light microscopy after the rats were sacrificed after 30 days treatment. The mRNA expressions of transforming growth factor-beta 1 (TGF-beta1) and type-1 plasminogen activator inhibitor (PAI-1) in renal cortex were measured by transcription-polymerase chain reaction (RT-PCR). The protein expressions of PAI-1, fibronectin (FN) and TGF-beta1 were detected by western blotting and immunohistochemistry respectively. In addition, levels of malondialdehyde (MDA) and the activity of antioxidants including superoxide diamutase (SOD), glutathione peroxidase (GSH-PX) in the cortex of kidney were measured.

RESULTS

In untreated diabetic rats, the glomerular volume, the expression of FN and the urinary albumin excretion increased. The mRNA and protein expression of PAI-1 and TGF-beta1 significantly increased in the STZ group. Treatment with SPL partially reversed these changes. Meanwhile, elevated MDA levels as well as decreased SOD and GSH-PX activities in the cortex of kidney were significantly ameliorated in the treated group.

CONCLUSION

SPL ameliorates the glomerular injury in STZ-induced early diabetic renal injury, which is closely related with the reduction of PAI-1 and TGF-beta1 expression and the attenuation of oxidative stress.