sphingosine-kinase and Fibrosis

Over the last decade, various sphingolipid subspecies have gained increasing attention as important signaling molecules that regulate a multitude of physiological and pathophysiological processes including inflammation and tissue remodeling. These mediators include ceramide, sphingosine 1-phosphate (S1P), the cerebroside glucosylceramide, lactosylceramide, and the gangliosides GM3 and Gb3. These lipids have been shown to accumulate in various chronic kidney diseases that typically end in renal fibrosis and ultimately renal failure. This review will summarize the effects and contributions of those enzymes that regulate the generation and interconversion of these lipids, notably the acid sphingomyelinase, the acid sphingomyelinase-like protein SMPDL3B, the sphingosine kinases, the S1P lyase, the glucosylceramide synthase, the GM3 synthase, and the α-galactosidase A, to renal fibrotic diseases. Strategies of manipulating these enzymes for therapeutic purposes and the impact of existing drugs on renal pathologies will be discussed.

Topics: alpha-Galactosidase; Animals; Fibrosis; Humans; Phosphotransferases (Alcohol Group Acceptor); Proprotein Convertases; Renal Insufficiency, Chronic; Serine Endopeptidases; Sialyltransferases; Signal Transduction; Sphingolipids; Sphingomyelin Phosphodiesterase

Chronic kidney diseases including glomerulonephritis are often accompanied by acute or chronic inflammation that leads to an increase in extracellular matrix (ECM) production and subsequent glomerulosclerosis. Glomerulonephritis is one of the leading causes for end-stage renal failure with high morbidity and mortality, and there are still only a limited number of drugs for treatment available. In this MiniReview, we discuss the possibility of targeting sphingolipids, specifically the sphingosine kinase 1 (SphK1) and sphingosine 1-phosphate (S1P) pathway, as new therapeutic strategy for the treatment of glomerulonephritis, as this pathway was demonstrated to be dysregulated under disease conditions. Sphingosine 1-phosphate is a multifunctional signalling molecule, which was shown to influence several hallmarks of glomerulonephritis including mesangial cell proliferation, renal inflammation and fibrosis. Most importantly, the site of action of S1P determines the final effect on disease progression. Concerning renal fibrosis, extracellular S1P acts pro-fibrotic via activation of cell surface S1P receptors, whereas intracellular S1P was shown to attenuate the fibrotic response. Interference with S1P signalling by treatment with FTY720, an S1P receptor modulator, resulted in beneficial effects in various animal models of chronic kidney diseases. Also, sonepcizumab, a monoclonal anti-S1P antibody that neutralizes extracellular S1P, and a S1P-degrading recombinant S1P lyase are promising new strategies for the treatment of glomerulonephritis. In summary, especially due to the bifunctionality of S1P, the SphK1/S1P pathway provides multiple target sites for the treatment of chronic kidney diseases.

Topics: Animals; Cell Proliferation; Disease Models, Animal; Fibrosis; Fingolimod Hydrochloride; Glomerulonephritis; Humans; Inflammation; Kidney Failure, Chronic; Lysophospholipids; Molecular Targeted Therapy; Phosphotransferases (Alcohol Group Acceptor); Propylene Glycols; Receptors, Lysosphingolipid; Signal Transduction; Sphingosine

Persistent transforming growth factor beta (TGF-beta) signaling is the major factor contributing to scleroderma (SSc) fibrosis. This review will summarize recent progress on the noncanonical TGF-beta signaling pathways and their role in SSc fibrosis.. Canonical TGF-beta signaling involves activation of the TGF-beta receptors and downstream signal transducers Smad2/3. The term noncanonical TGF-beta signaling includes a variety of intracellular signaling pathways activated by TGF-beta independently of Smad2/3 activation. There is evidence that these pathways play important role in SSc fibrosis. In a subset of SSc fibroblasts, a multiligand receptor complex consisting of TGF-beta and CCN2 receptors drives constitutive activation of the Smad1 pathway. CCN2 is also a primary effector of this pathway, thus establishing an autocrine loop that amplifies TGF-beta signaling. SSc fibroblasts also demonstrate reduced expression of endogenous antagonists of TGF-beta signaling including transcriptional repressors, Friend leukemia integration-1 and perixosome proliferator-activated receptor-gamma, as well as inhibitor of Smad3 phosphorylation, PTEN. PTEN is a key mediator of the cross-talk between the sphingosine kinase and the TGF-beta pathways.. Discovery of the role of noncanonical TGF-beta signaling in fibrosis offers new molecular targets for the antifibrotic therapies. Due to the heterogeneous nature of SSc, knowledge of these pathways could help to tailor the therapy to the individual patient depending on the activation status of a specific profibrotic pathway.

Topics: Animals; Autocrine Communication; Collagen; Connective Tissue Growth Factor; Fibrosis; Humans; Models, Biological; Phosphotransferases (Alcohol Group Acceptor); PTEN Phosphohydrolase; Scleroderma, Systemic; Signal Transduction; Smad1 Protein; Transforming Growth Factor beta

Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure. Thus, there is an urgent need for more effective strategies to aid in cardiac protection. Our previous work found that sphingosine-1-phosphate (S1P) could ameliorate cardiac hypertrophy. In this study, we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.. Eight-week-old male C57BL/6 mice were randomly divided into a sham, transverse aortic constriction (TAC) or a TAC+S1P treatment group.. We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease in α-smooth muscle actin (α-SMA) and collagen type I (COL I) expression compared with the TAC group. We also found that one of the key S1P enzymes, sphingosine kinase 2 (SphK2), which was mainly distributed in cytoblasts, was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro. In addition, our in vitro results showed that S1P treatment activated extracellular regulated protein kinases (ERK) phosphorylation mainly through the S1P receptor 2 (S1PR2) and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.. These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart. This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.

Topics: Animals; Fibrosis; Lysophospholipids; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Phosphotransferases (Alcohol Group Acceptor); Sphingosine; Ventricular Remodeling

Tumor necrosis factor superfamily protein 14 (TNFSF14) was recently identified as a risk factor in some fibrosis diseases. However, the role of TNFSF14 in renal fibrosis pathogenesis remains unknown.. It was found that TNFSF14 levels were significantly increased both in UUO-induced renal fibrotic mice and in patients with fibrotic nephropathy, compared with those in controls. Accordingly,. TNFSF14 is a novel pro-fibrotic factor of renal fibrosis, for which TNFSF14 up-regulates Sphk1 expression, which may be the underlying mechanism of TNFSF14-mediated renal fibrosis.. We investigated the effect of TNFSF14 on renal fibrosis and the relationship between TNFSF14 and pro-fibrotic factor sphingosine kinase 1 (Sphk1) by using the unilateral urethral obstruction (UUO)-induced mice renal fibrosis as a model and the specimen of patients with fibrosis nephropathy, by Masson trichrome staining, immunohistochemistry, qRT-PCR, and western blot analysis.

Topics: Animals; Disease Models, Animal; Fibrosis; Humans; Inflammation; Kidney; Kidney Diseases; Mice; Mice, Knockout; Phosphotransferases (Alcohol Group Acceptor); Tumor Necrosis Factor Ligand Superfamily Member 14

A concomitant action of multiple profibrotic mediators appears crucial in the development and progression of fibrosis. Sphingosine kinase/sphingosine 1 phosphate and transforming growth factor-β/Smads pathways are both involved in pathogenesis of fibrosis in several organs by controlling differentiation of fibroblasts to myofibroblasts and the epithelial to-mesenchymal transition. However, their direct involvement in chronic colitis-associated fibrosis it is not yet known. In this study we evaluated the immunohistochemical expression of some proteins implicated in sphingosine kinase/sphingosine 1 phosphate and transforming growth factor-β/Smads pathways in Dextrane Sodium Sulphate (DSS)-induced colorectal fibrosis in mice. Compared to control mice, DSS-induced chronic colitis mice developed a marked intestinal fibrosis associated with a concomitant overexpression of TGF-β, p-Smad3, α-SMA, collagen I-III, SPHK1, RhoA, PI3K, Akt, p-Akt, p-mTOR. This study highlights the relationship between the two pathways and the possible role of SPHK1 in the intestinal fibrosis.  These results, if confirmed by in vitro studies, may have important clinical implications in the development of new therapeutical approaches in inflammatory bowel disease.

Topics: Animals; Colitis; Disease Models, Animal; Fibrosis; Immunohistochemistry; Intestines; Lysophospholipids; Mice; Mice, Inbred C57BL; Phosphotransferases (Alcohol Group Acceptor); Reference Standards; Signal Transduction; Smad3 Protein; Sphingosine; Transforming Growth Factor beta

Autophagy is an important homoeostatic mechanism for the lysosomal degradation of protein aggregates and damaged cytoplasmic components. Recent studies suggest that autophagy which is induced by TGF-β1 suppresses kidney fibrosis in renal tubular epithelial cells (RTECs) of obstructed kidneys. Sphingosine kinase 1(SK1), converting sphingosine into endogenous sphingosine-1-phosphate (S1P), was shown to modulate autophagy and involved in the processes of fibrotic diseases. Since SK1 activity is also up-regulated by TGF-β1, we explored its effect on the induction of autophagy and development of renal fibrosis in this study. In vitro, SK1 expression and activity were markedly increased by TGF-β1 stimulation in a time and concentration dependent manner, and concomitant changes in autophagic response were observed in HK-2 cells. Further, knockdown of SK-1 led to a decrease of autophagy whereas overexpression of SK1 caused a greater induction of autophagy. In addition, overexpression of SK1 resulted in decreased of mature TGF-β levels through autophagic degradation. In vivo, SK1 enzymatic activity and autophagic response were both up-regulated in a mouse model of kidney fibrosis induced by unilateral ureteral obstruction (UUO); meanwhile, increased of mature TGF-β1 and deposition of extracellular matrix (ECM) were observed in tubulointerstitial areas compared with sham-operated mice. However, aggravation of renal fibrosis was detected when SK1 inhibitor PF-543 was applied to suppress SK1 enzymatic activity in UUO mice. At the same time, autophagy was also inhibited by PF-543. Thus, our findings suggest that SK1 activation is renoprotective via induction of autophagy in the fibrotic process.

Topics: Animals; Autophagy; Cell Line; Enzyme Activation; Epithelial Cells; Fibrosis; Humans; Kidney Tubules; Male; Methanol; Mice; Phosphotransferases (Alcohol Group Acceptor); Pyrrolidines; Sulfones; Transforming Growth Factor beta1; Up-Regulation; Ureteral Obstruction

Focal segmental glomerulosclerosis (FSGS) typically presents with nephrotic range proteinuria, which could eventually develop into end-stage renal disease. Resveratrol (RSV) is a natural polyphenol compound, which has been reported to suppress inflammatory response and renal interstitial fibrosis. This study is aimed at evaluating the renoprotective effect of RSV treatment on adriamycin-induced FSGS.. In Balb/c mice, adriamycin nephropathy was induced by adriamycin (10 mg/kg body weight, diluted in normal saline) via a tail vein on day 0. Then the mice were treated with RSV (40 mg/kg body weight) once daily by oral gavage, again starting on the day of adriamycin injection and continued for 6 weeks. At 6 weeks, the mice were sacrificed; kidneys and blood samples were collected for further analysis.. When treated with adriamycin, the expressions of C3aR, C5aR, sphingosine kinase 1 (Sphk1), and soluble urokinase-type plasminogen activator receptor (suPAR) were upregulated, while RSV treatment could inhibit the expressions of C3aR, C5aR, Sphk1, and suPAR, eventually leading to anti-inflammatory and anti-fibrosis conditions.. RSV attenuates adriamycin-induced FSGS through C3aR/C5aR-Sphk1 pathway.

Topics: Animals; Anti-Inflammatory Agents; Doxorubicin; Fibrosis; Glomerulosclerosis, Focal Segmental; Kidney; Male; Mice; Mice, Inbred BALB C; Phosphotransferases (Alcohol Group Acceptor); Receptor, Anaphylatoxin C5a; Receptors, G-Protein-Coupled; Resveratrol; Signal Transduction; Stilbenes

To delineate the role of Sphingolipids (SPLs) in the human cornea and their cross-talks with transforming growth factor beta (TGF-β) in order to develop novel, non-invasive therapies.. Human corneal fibroblasts (HCFs) were harvested from healthy donors, stimulated with Vitamin C to promote extracellular matrix assembly, treated with exogenous sphingosine-1-phosphate (S1P) or sphingosine kinase inhibitor 2 (SPHK I2) and isolated after 4 weeks for further analysis.. Data showed that S1P led to a significant decrease in cellular migration where SPHK I2 just delayed it for 24h. Significant modulation of the sphingolipid pathway was also noted. Sphingosine kinase-1 (SphK1) was significantly downregulated upon exogenous stimulation with S1P at a concentration of 5μM and Sphingosine kinase-2 (SphK2) was also significantly downregulated at concentrations of 0.01μM, 0.1μM, and 5μM; whereas no effects were observed upon stimulation with SPHK I2. S1PR3 was significantly downregulated by 0.1μM and 5μM S1P and upregulated by 5μM and 10μM SPHK I2. Furthermore, both S1P and SPHK I2 regulated corneal fibrosis markers such as alpha-smooth muscle actin, collagen I, III, and V. We also investigated the interplay between two TGF-β isoforms and S1P/SPHK I2 treatments and found that TGF-β1 and TGF-β3 were both significantly upregulated with the 0.1μM S1P but were significantly downregulated with the 5μM S1P concentration. When TGF-β1 was compared directly to TGF-β3 expression, we observed that TGF-β3 was significantly downregulated compared to TGF-β1 in the 5μM concentration of S1P. No changes were observed upon SPHK I2 treatment.. Our study delineates the role of sphingolipids in the human cornea and highlights their different activities based on the cell/tissue type.

Topics: Blotting, Western; Cell Extracts; Cell Movement; Corneal Stroma; Fibroblasts; Fibrosis; Humans; Lysophospholipids; Phosphotransferases (Alcohol Group Acceptor); Protein Isoforms; Protein Kinase Inhibitors; Signal Transduction; Sphingolipids; Sphingosine; Transforming Growth Factor beta; Wound Healing

Maladaptive repair after AKI may lead to progressive fibrosis and decline in kidney function. Sphingosine 1-phosphate has an important role in kidney injury and pleiotropic effects in fibrosis. We investigated the involvement of sphingosine kinase 1 and 2 (SphK1 and SphK2), which phosphorylate sphingosine to produce sphingosine 1-phosphate, in kidney fibrosis induced by folic acid (FA) or unilateral ischemia-reperfusion injury. Analysis of Masson trichrome staining and fibrotic marker protein and mRNA expression 14 days after AKI revealed that wild-type (WT) and

Topics: Animals; Fibrosis; Interferon-gamma; Kidney; Kidney Diseases; Mice; Phosphotransferases (Alcohol Group Acceptor)

Hyperglycemia induces all isoforms of transforming growth factor β (TGFβ), which in turn play key roles in inflammation and fibrosis that characterize diabetic nephropathy. Sphingosine 1-phosphate (S1P) is a signaling sphingolipid, derived from sphingosine by the action of sphingosine kinase (SK). S1P mediates many biological processes, which mimic TGFβ signaling. To determine the role of SK1 and S1P in inducing fibrosis and inflammation, and the interaction with TGFβ-1, 2 and 3 signalling in diabetic nephropathy, human proximal tubular cells (HK2 cells) were exposed to normal (5 mmol/L) or high (30 mmol/L) glucose or TGFβ-1, -2, -3 ± an SK inhibitor (SKI-II) or SK1 siRNA. Control and diabetic wild type (WT) and SK1(-/-) mice were studied. Fibrotic and inflammatory markers, and relevant downstream signalling pathways were assessed. SK1 mRNA and protein expression was increased in HK2 cells exposed to high glucose or TGFβ1,-2,-3. All TGFβ isoforms induced fibronectin, collagen IV and macrophage chemoattractant protein 1 (MCP1), which were reversed by both SKI-II and SK1 siRNA. Exposure to S1P increased phospho-p44/42 expression, AP-1 binding and NFkB phosphorylation. WT diabetic mice exhibited increased renal cortical S1P, fibronectin, collagen IV and MCP1 mRNA and protein expression compared to SK1(-/-) diabetic mice. In summary, this study demonstrates that inhibiting the formation of S1P reduces tubulointerstitial renal inflammation and fibrosis in diabetic nephropathy.

Topics: Animals; Biomarkers; Cell Line; Diabetic Nephropathies; Dose-Response Relationship, Drug; Enzyme Inhibitors; Extracellular Matrix; Extracellular Signal-Regulated MAP Kinases; Fibrosis; Gene Expression Regulation, Enzymologic; Gene Silencing; Glucose; Humans; Inflammation; Kidney Cortex; Kidney Tubules; Lysophospholipids; Male; Mice; NF-kappa B; Phosphoproteins; Phosphotransferases (Alcohol Group Acceptor); Sphingosine; Transcription Factor AP-1; Transforming Growth Factor beta

The matricellular protein connective tissue growth factor (CTGF/CCN2) is recognized as key player in the onset of fibrosis in various tissues, including skeletal muscle. In many circumstances, CTGF has been shown to be induced by transforming growth factor beta (TGFβ) and accounting, at least in part, for its biological action. In this study it was verified that in cultured myoblasts CTGF/CCN2 causes their transdifferentiation into myofibroblasts by up-regulating the expression of fibrosis marker proteins α-smooth muscle actin and transgelin. Interestingly, it was also found that the profibrotic effect exerted by CTGF/CCN2 was mediated by the sphingosine kinase (SK)-1/S1P3 signaling axis specifically induced by the treatment with the profibrotic cue. Following CTGF/CCN2-induced up-regulation, S1P3 became the S1P receptor subtype expressed at the highest degree, at least at mRNA level, and was thus capable of readdressing the sphingosine 1-phosphate signaling towards fibrosis rather than myogenic differentiation. Another interesting finding is that CTGF/CCN2 silencing prevented the TGFβ-dependent up-regulation of SK1/S1P3 signaling axis and strongly reduced the profibrotic effect exerted by TGFβ, pointing at a crucial role of endogenous CTGF/CCN2 generated following TGFβ challenge in the transmission of at least part of its profibrotic effect. These results provide new insights into the molecular mechanism by which CTGF/CCN2 drives its biological action and strengthen the concept that SK1/S1P3 axis plays a critical role in the onset of fibrotic cell phenotype.

Topics: Animals; Cell Line; Cell Transdifferentiation; Connective Tissue Growth Factor; Dose-Response Relationship, Drug; Fibrosis; Mice; Myoblasts, Skeletal; Myofibroblasts; Phosphotransferases (Alcohol Group Acceptor); Receptors, Lysosphingolipid; Recombinant Proteins; RNA Interference; RNA, Messenger; Signal Transduction; Sphingosine-1-Phosphate Receptors; Time Factors; Transfection; Transforming Growth Factor beta1; Up-Regulation

PPARγ agonists [thiazolidinediones (TZDs)] are known to exert anti-fibrotic effects in the kidney. In addition, we previously demonstrated that sphingosine kinase 1 (SK-1) and intracellular sphingosine-1-phosphate (S1P), by reducing the expression of connective tissue growth factor (CTGF), have a protective role in the fibrotic process.. Here, we investigated the effect of TZDs on intracellular sphingolipid levels and the transcriptional regulation of SK-1 in mesangial cells to evaluate potential novel aspects of the anti-fibrotic capacity of TZDs.. Stimulation with the TZDs, troglitazone and rosiglitazone, led to increased S1P levels in rat mesangial cells. This was paralleled by increased SK-1 activity as a consequence of direct effects of the TZDs on SK-1 expression. GW-9662, a PPARγ antagonist, inhibited the stimulating effect of TZDs on SK-1 mRNA and activity levels and intracellular S1P concentrations. Furthermore, SK-1 up-regulation by TZDs was functionally coupled with lower amounts of pro-fibrotic CTGF. SK-1 inhibition with SKI II almost completely abolished this effect in a dose-dependent manner. Moreover, the CTGF lowering effect of TZDs was fully blocked in MC isolated from SK-1 deficient mice (SK-1(-/-) ) as well as in glomeruli of SK-1(-/-) mice compared with wild-type mice treated with TRO and RSG.. These data show that TZD-induced SK-1 up-regulation results in lower amounts of CTGF, demonstrating novel facets for the anti-fibrotic effects of this class of drugs.

Topics: Animals; Blotting, Western; Cell Culture Techniques; Cells, Cultured; Connective Tissue Growth Factor; Enzyme Activation; Female; Fibrosis; Humans; Lysophospholipids; Mesangial Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutagenesis, Site-Directed; Phosphotransferases (Alcohol Group Acceptor); PPAR gamma; Promoter Regions, Genetic; Rats; Real-Time Polymerase Chain Reaction; Sphingosine; Thiazolidinediones; Up-Regulation

Sphingosine kinase 1 (SPHK1), its product sphingosine-1-phosphate (S1P), and S1P receptor subtypes have been suggested to play protective roles for cardiomyocytes in animal models of ischaemic preconditioning and cardiac ischaemia/reperfusion injury. To get more insight into roles for SPHK1 in vivo, we have generated SPHK1-transgenic (TG) mice and analysed the cardiac phenotype.. SPHK1-TG mice overexpressed SPHK1 in diverse tissues, with a nearly 20-fold increase in enzymatic activity. The TG mice grew normally with normal blood chemistry, cell counts, heart rate, and blood pressure. Unexpectedly, TG mice with high but not low expression levels of SPHK1 developed progressive myocardial degeneration and fibrosis, with upregulation of embryonic genes, elevated RhoA and Rac1 activity, stimulation of Smad3 phosphorylation, and increased levels of oxidative stress markers. Treatment of juvenile TG mice with pitavastatin, an established inhibitor of the Rho family G proteins, or deletion of S1P3, a major myocardial S1P receptor subtype that couples to Rho GTPases and transactivates Smad signalling, both inhibited cardiac fibrosis with concomitant inhibition of SPHK1-dependent Smad-3 phosphorylation. In addition, the anti-oxidant N-2-mercaptopropyonylglycine, which reduces reactive oxygen species (ROS), also inhibited cardiac fibrosis. In in vivo ischaemia/reperfusion injury, the size of myocardial infarct was 30% decreased in SPHK1-TG mice compared with wild-type mice.. These results suggest that chronic activation of SPHK1-S1P signalling results in both pathological cardiac remodelling through ROS mediated by S1P3 and favourable cardioprotective effects.

Topics: Animals; Fibrosis; Fluorescent Antibody Technique; Mice; Mice, Inbred C57BL; Mice, Transgenic; Myocardial Reperfusion Injury; Myocardium; Neuropeptides; Phosphotransferases (Alcohol Group Acceptor); Quinolines; rac GTP-Binding Proteins; rac1 GTP-Binding Protein; Reactive Oxygen Species; Receptors, Lysosphingolipid; rho GTP-Binding Proteins; rhoA GTP-Binding Protein; Sphingosine-1-Phosphate Receptors

Transforming growth factor-beta2 (TGF-beta2) stimulates the expression of pro-fibrotic connective tissue growth factor (CTGF) during the course of renal disease. Because sphingosine kinase-1 (SK-1) activity is also upregulated by TGF-beta, we studied its effect on CTGF expression and on the development of renal fibrosis. When TGF-beta2 was added to an immortalized human podocyte cell line we found that it activated the promoter of SK-1, resulting in upregulation of its mRNA and protein expression. Further, depletion of SK-1 by small interfering RNA or its pharmacological inhibition led to accelerated CTGF expression in the podocytes. Over-expression of SK-1 reduced CTGF induction, an effect mediated by intracellular sphingosine-1-phosphate. In vivo, SK-1 expression was also increased in the podocytes of kidney sections of patients with diabetic nephropathy when compared to normal sections of kidney obtained from patients with renal cancer. Similarly, in a mouse model of streptozotocin-induced diabetic nephropathy, SK-1 and CTGF were upregulated in podocytes. In SK-1 deficient mice, exacerbation of disease was detected by increased albuminuria and CTGF expression when compared to wild-type mice. Thus, SK-1 activity has a protective role in the fibrotic process and its deletion or inhibition aggravates fibrotic disease.

Topics: Albuminuria; Animals; Cell Line; Connective Tissue Growth Factor; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Down-Regulation; Fibrosis; Gene Expression Regulation, Enzymologic; Humans; Lysophospholipids; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Phosphotransferases (Alcohol Group Acceptor); Podocytes; Promoter Regions, Genetic; Protein Kinase Inhibitors; RNA Interference; RNA, Messenger; Smad4 Protein; Sphingosine; Time Factors; Transforming Growth Factor beta1; Transforming Growth Factor beta2; Up-Regulation

Renal fibrosis contributes to glomerulosclerosis and tubulointerstitial damage in chronic kidney disease. A well-established pathway implicated in the progression of fibrosis is the induction of connective tissue growth factor by transforming growth factor-beta, resulting in the accumulation of extracellular matrix proteins. Ren and colleagues demonstrate that sphingosine kinase-1 is involved in the regulation of this pathway in the glomerulus. This raises the possibility of targeting sphingosine kinase-1 to prevent fibrosis in chronic kidney disease patients.

Topics: Animals; Chronic Disease; Connective Tissue Growth Factor; Disease Progression; Fibrosis; Humans; Kidney Diseases; Lysophospholipids; Phosphotransferases (Alcohol Group Acceptor); Podocytes; Protein Kinase Inhibitors; Sphingosine; Transforming Growth Factor beta2

Sphingosine kinase 1 (SPK1) has been identified as a central mediator of ischemia preconditioning and plays a protective role in ischemia/reperfusion (I/R)-induced cardiomyocyte death. In the present study, we investigated the protective effect of adenovirus-mediated SPK1 gene (Ad-SPK1) transfer on I/R-induced cardiac injury, and evaluated its therapeutic action on postinfarction heart failure. Cardiac SPK1 activity was increased about 5-fold by injection of Ad-SPK1, compared with injection of adenovirus carrying the green fluorescent protein gene (Ad-GFP). A more potent performance and a lower incidence of arrhythmia were observed in Ad-SPK1-injected hearts during the reperfusion period, compared with Ad-GFP-injected hearts. An enzymatic activity assay showed that creatine kinase release was also less in Ad-SPK1-injected hearts. To investigate the therapeutic action of the SPK1 gene on postischemic heart failure, the left anterior descending branch of the coronary artery in Wistar rats was ligated after direct intramyocardial injection of Ad-SPK1 or Ad-GFP as a control. Ad-SPK1 injection significantly preserved cardiac systolic and diastolic function, as evidenced by left ventricular (LV) systolic pressure, LV end-diastolic pressure, and peak velocity of contraction (dP/dt). The LV morphometric parameters of Ad-SPK1-treated animals were also preserved. In addition, SPK1 gene delivery significantly enhanced angiogenesis and reduced fibrosis. These results demonstrate that adenovirus-mediated SPK1 gene transfer could efficiently prevent I/R-induced myocardial injury and attenuate postischemic heart failure. Thus, SPK1 gene delivery would be a novel strategy for the treatment of coronary heart disease.

Topics: Adenoviridae; Animals; Arrhythmias, Cardiac; Creatine Kinase; Disease Models, Animal; Fibrosis; Genetic Therapy; Genetic Vectors; Myocardial Contraction; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Myocytes, Cardiac; Neovascularization, Physiologic; Organ Culture Techniques; Phosphotransferases (Alcohol Group Acceptor); Rats; Rats, Wistar; Recovery of Function