Heparanase protects the heart against chemical or ischemia/reperfusion injury

Heparanase Stimulation of Physiologic Cardiac Hypertrophy Is Suppressed After Chronic Diabetes, Resulting in Cardiac Remodeling and Dysfunction

In addition to controlling smooth muscle tone in coronary vessels, endothelial cells also influence subjacent cardiomyocyte growth. Because heparanase, with exclusive expression in endothelial cells, enables extracellular matrix remodeling, angiogenesis, metabolic reprogramming, and cell survival, it is conceivable that it could also encourage development of cardiac hypertrophy. Global heparanase overexpression resulted in physiologic cardiac hypertrophy, likely an outcome of HSPG clustering and activation of hypertrophic signaling. The heparanase autocrine effect of releasing neuregulin-1 could have also contributed to this overexpression. Hyperglycemia induced by streptozotocin-induced diabetes sensitized the heart to flow-induced release of heparanase and neuregulin-1. Despite this excess secretion, progression of diabetes caused significant gene expression changes related to mitochondrial metabolism and cell death that led to development of pathologic hypertrophy and heart dysfunction. Physiologic cardiac hypertrophy was also observed in rats with cardiomyocyte-specific vascular endothelial growth factor B overexpression. When perfused, hearts from these animals released significantly higher amounts of both heparanase and neuregulin-1. However, subjecting these animals to diabetes triggered robust transcriptome changes related to metabolism and a transition to pathologic hypertrophy. Our data suggest that in the absence of mechanisms that support cardiac energy generation and prevention of cell death, as seen after diabetes, there is a transition from physiologic to pathologic cardiac hypertrophy and a decline in cardiac function.

ARTICLE HIGHLIGHTS

Myocardial reperfusion injury exacerbation due to ALDH2 deficiency is mediated by neutrophil extracellular traps and prevented by leukotriene C4 inhibition

BACKGROUND AND AIMS

The Glu504Lys polymorphism in the aldehyde dehydrogenase 2 (ALDH2) gene is closely associated with myocardial ischaemia/reperfusion injury (I/RI). The effects of ALDH2 on neutrophil extracellular trap (NET) formation (i.e. NETosis) during I/RI remain unknown. This study aimed to investigate the role of ALDH2 in NETosis in the pathogenesis of myocardial I/RI.

METHODS

The mouse model of myocardial I/RI was constructed on wild-type, ALDH2 knockout, peptidylarginine deiminase 4 (Pad4) knockout, and ALDH2/PAD4 double knockout mice. Overall, 308 ST-elevation myocardial infarction patients after primary percutaneous coronary intervention were enrolled in the study.

RESULTS

Enhanced NETosis was observed in human neutrophils carrying the ALDH2 genetic mutation and ischaemic myocardium of ALDH2 knockout mice compared with controls. PAD4 knockout or treatment with NETosis-targeting drugs (GSK484, DNase1) substantially attenuated the extent of myocardial damage, particularly in ALDH2 knockout. Mechanistically, ALDH2 deficiency increased damage-associated molecular pattern release and susceptibility to NET-induced damage during myocardial I/RI. ALDH2 deficiency induced NOX2-dependent NETosis via upregulating the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/leukotriene C4 (LTC4) pathway. The Food and Drug Administration-approved LTC4 receptor antagonist pranlukast ameliorated I/RI by inhibiting NETosis in both wild-type and ALDH2 knockout mice. Serum myeloperoxidase-DNA complex and LTC4 levels exhibited the predictive effect on adverse left ventricular remodelling at 6 months after primary percutaneous coronary intervention in ST-elevation myocardial infarction patients.

CONCLUSIONS

ALDH2 deficiency exacerbates myocardial I/RI by promoting NETosis via the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/LTC4/NOX2 pathway. This study hints at the role of NETosis in the pathogenesis of myocardial I/RI, and pranlukast might be a potential therapeutic option for attenuating I/RI, particularly in individuals with the ALDH2 mutation.

Computational prognostic evaluation of Alzheimer's drugs from FDA-approved database through structural conformational dynamics and drug repositioning approaches

Drug designing is high-priced and time taking process with low success rate. To overcome this obligation, computational drug repositioning technique is being promptly used to predict the possible therapeutic effects of FDA approved drugs against multiple diseases. In this computational study, protein modeling, shape-based screening, molecular docking, pharmacogenomics, and molecular dynamic simulation approaches have been utilized to retrieve the FDA approved drugs against AD. The predicted MADD protein structure was designed by homology modeling and characterized through different computational resources. Donepezil and galantamine were implanted as standard drugs and drugs were screened out based on structural similarities. Furthermore, these drugs were evaluated and based on binding energy (Kcal/mol) profiles against MADD through PyRx tool. Moreover, pharmacogenomics analysis showed good possible associations with AD mediated genes and confirmed through detail literature survey. The best 6 drug (darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar) further docked and analyzed their interaction behavior through hydrogen binding. Finally, MD simulation study were carried out on these drugs and evaluated their stability behavior by generating root mean square deviation and fluctuations (RMSD/F), radius of gyration (Rg) and soluble accessible surface area (SASA) graphs. Taken together, darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar displayed good lead like profile as compared with standard and can be used as possible therapeutic agent in the treatment of AD after in-vitro and in-vivo assessment.

Heparanase Increases Podocyte Survival and Autophagic Flux after Adriamycin-Induced Injury

The kidney glomerular filtration barrier (GFB) is enriched with heparan sulfate (HS) proteoglycans, which contribute to its permselectivity. The endoglycosidase heparanase cleaves HS and hence appears to be involved in the pathogenesis of kidney injury and glomerulonephritis. We have recently reported, nonetheless, that heparanase overexpression preserved glomerular structure and kidney function in an experimental model of Adriamycin-induced nephropathy. To elucidate mechanisms underlying heparanase function in podocytes-key GFB cells, we utilized a human podocyte cell line and transgenic mice overexpressing heparanase. Notably, podocytes overexpressing heparanase (H) demonstrated significantly higher survival rates and viability after exposure to Adriamycin or hydrogen peroxide, compared with mock-infected (V) podocytes. Immunofluorescence staining of kidney cryo-sections and cultured H and V podocytes as well as immunoblotting of proteins extracted from cultured cells, revealed that exposure to toxic injury resulted in a significant increase in autophagic flux in H podocytes, which was reversed by the heparanase inhibitor, Roneparstat (SST0001). Heparanase overexpression was also associated with substantial transcriptional upregulation of autophagy genes BCN1, ATG5, and ATG12, following Adriamycin treatment. Moreover, cleaved caspase-3 was attenuated in H podocytes exposed to Adriamycin, indicating lower apoptotic cell death in H vs. V podocytes. Collectively, these findings suggest that in podocytes, elevated levels of heparanase promote cytoprotection.

[Down-regulation of SIK2 expression alleviates myocardial ischemia-reperfusion injury in rats by inhibiting autophagy through the mTOR-ULK1 signaling pathway]

OBJECTIVE

To explore the role of salt-inducible kinase 2 (SIK2) in myocardial ischemia-reperfusion (IR) injury in rats.

METHODS

Fifteen male SD rats were randomized equally into sham operation group, myocardial IR model group, and SIK2 inhibitor group (in which the rats were treated with intravenous injection of 10 mg/kg bosutinib via the left femoral vein 24 h before modeling). Ultrasound was used to detect the cardiac function of the rats, and myocardial pathologies were observed with HE staining. Transmission electron microscopy was used to observe autophagy of myocardial cells, and Western blotting was performed to detect the contents of the autophagy-related proteins SIK2, LC3B, Beclin-1, p62 and the expressions of p-mTOR, mTOR, p-ULK1, and ULK1 in myocardial tissue.

RESULTS

Myocardial IR injury significantly increased the number of autophagosomes (P < 0.05) and the expression of SIK2 protein (P < 0.01) in the myocardial tissues. Treatment with bosutinib before modeling obviously lowered the expression of SIK2 protein (P < 0.01), alleviated myocardial pathologies, and reduced the number of autophagosomes (P < 0.05) in the myocardial tissue. The rats with myocardial IR injury showed obviously lowered LVEF and FS values (P < 0.001), which were significantly improved by bosutinib treatment (P < 0.05); no significant difference was detected in IVSDd or LVPWDd among the 3 groups (P > 0.05). Myocardial IR injury obviously increased the expressions of LC3-II/LC3-I and Beclin-1 proteins and lowered the expression of p62 protein (P < 0.01), and these changes were significantly rescued by bosutinib treatment (P < 0.05). The rat models of myocardial IR injury showed significantly increased expression of p-ULK1 (Ser757) (P < 0.01) and lowered expression of p-mTOR protein (P < 0.0001) in the myocardium, and these changes were obviously reversed by bosutinib (P < 0.01 or 0.05); there was no significant difference in mTOR and ULK1 expressions among the 3 groups (P > 0.05).

CONCLUSION

SIK2 may promote autophagy through the mTOR/ULK1 signaling pathway, and inhibiting SIK2 can reduce abnormal autophagy and alleviate myocardial IR injury in rats.

Heparanase-1 is upregulated by hepatitis C virus and favors its replication

BACKGROUND & AIMS

Over time, chronic HCV infection can lead to hepatocellular carcinoma (HCC), a process that involves changes to the liver extracellular matrix (ECM). However, the exact mechanisms by which HCV induces HCC remain unclear. Therefore, we sought to investigate the impact of HCV on the liver ECM, with a focus on heparanase-1 (HPSE).

METHODS

HPSE expression was assessed by quantitative reverse-transcription PCR, immunoblotting and immunofluorescence in liver biopsies infected or not with HCV, and in 10-day-infected hepatoma Huh7.5 cells. Cell lines deficient for or overexpressing HPSE were established to study its role during infection.

RESULTS

HCV propagation led to significant HPSE induction, in vivo and in vitro. HPSE enhanced infection when exogenously expressed or supplemented as a recombinant protein. Conversely, when HPSE expression was downregulated or its activity blocked, HCV infection dropped, suggesting a role of HPSE in the HCV life cycle. We further studied the underlying mechanisms of such observations and found that HPSE favored HCV release by enhancing CD63 synthesis and exosome secretion, but not by stimulating HCV entry or genome replication. We also showed that virus-induced oxidative stress was involved in HPSE induction, most likely through NF-κB activation.

CONCLUSIONS

We report for the first time that HCV infection is favored by HPSE, and upregulates HPSE expression and secretion, which may result in pathogenic alterations of the ECM.

LAY SUMMARY

Chronic hepatitis C virus (HCV) infection can lead to hepatocellular carcinoma development in a process that involves derangement of the extracellular matrix (ECM). Herein, we show that heparanase-1, a protein involved in ECM degradation and remodeling, favors HCV infection and is upregulated by HCV infection; this upregulation may result in pathogenic alterations of the ECM.

Beta-cell specific Insr deletion promotes insulin hypersecretion and improves glucose tolerance prior to global insulin resistance

Insulin receptor (Insr) protein is present at higher levels in pancreatic β-cells than in most other tissues, but the consequences of β-cell insulin resistance remain enigmatic. Here, we use an Ins1cre knock-in allele to delete Insr specifically in β-cells of both female and male mice. We compare experimental mice to Ins1cre-containing littermate controls at multiple ages and on multiple diets. RNA-seq of purified recombined β-cells reveals transcriptomic consequences of Insr loss, which differ between female and male mice. Action potential and calcium oscillation frequencies are increased in Insr knockout β-cells from female, but not male mice, whereas only male βInsrKO islets have reduced ATP-coupled oxygen consumption rate and reduced expression of genes involved in ATP synthesis. Female βInsrKO and βInsrHET mice exhibit elevated insulin release in ex vivo perifusion experiments, during hyperglycemic clamps, and following i.p. glucose challenge. Deletion of Insr does not alter β-cell area up to 9 months of age, nor does it impair hyperglycemia-induced proliferation. Based on our data, we adapt a mathematical model to include β-cell insulin resistance, which predicts that β-cell Insr knockout improves glucose tolerance depending on the degree of whole-body insulin resistance. Indeed, glucose tolerance is significantly improved in female βInsrKO and βInsrHET mice compared to controls at 9, 21 and 39 weeks, and also in insulin-sensitive 4-week old males. We observe no improved glucose tolerance in older male mice or in high fat diet-fed mice, corroborating the prediction that global insulin resistance obscures the effects of β-cell specific insulin resistance. The propensity for hyperinsulinemia is associated with mildly reduced fasting glucose and increased body weight. We further validate our main in vivo findings using an Ins1-CreERT transgenic line and find that male mice have improved glucose tolerance 4 weeks after tamoxifen-mediated Insr deletion. Collectively, our data show that β-cell insulin resistance in the form of reduced β-cell Insr contributes to hyperinsulinemia in the context of glucose stimulation, thereby improving glucose homeostasis in otherwise insulin sensitive sex, dietary and age contexts.

A novel danshensu/tetramethypyrazine derivative attenuates oxidative stress-induced autophagy injury via the AMPK-mTOR-Ulk1 signaling pathway in cardiomyocytes

Myocardial ischemia/reperfusion injury (MIRI) is an inevitable and unsolved clinical problem in the treatment of ischemic heart diseases. Compound DT-010 is a novel danshensu/tetramethylpyrazine derivative and was examined as a candidate for treating MIRI. In the present study, MTT, lactate dehydrogenase assay and Hoechst staining data indicated that DT-010 attenuated tert-butylhydroperoxide (t-BHP)-induced oxidative damage by increasing cell survival, reducing cell damage and decreasing apoptosis in H9c2 cardiomyocytes. Autophagy was assessed by western blotting for microtubule-associated protein 1A/1B-light chain 3 (LC3-II and LC3-I) expression, acridine orange and monodansylcadaverine staining for autophagosome formation and the monomeric red fluorescent protein-green fluorescent protein-LC3 assay for autophagic flow. t-BHP-induced cell damage was aggravated by the autophagy agonist rapamycin and alleviated by the autophagy blocker hydroxy-chloroquine, suggesting that autophagy was involved in t-BHP-induced cardiomyocyte injury. DT-010 pretreatment significantly prevented t-BHP-induced cell damage, which was partially but significantly abolished by rapamycin and significantly improved by hydroxy-chloroquine treatment. DT-010 treatment inhibited t-BHP-induced autophagy in H9c2 cells, reduced phosphorylation of 5'-AMP-activated protein kinase (AMPK) and promoted the phosphorylation of mTOR and unc-51 like autophagy activating kinase 1 (Ulk1). To conclude, DT-010 can serve as a potential candidate for myocardial ischemia-reperfusion injury therapy. The cardioprotective effects of DT-010 could be partially attributed to its inhibition of autophagy via the AMPK-mTOR-Ulk1 signaling pathway.

[Heparanase promotes trans-endothelial migration of hepatocarcinoma cells by inducing apoptosis of microvascular endothelial cells]

OBJECTIVE

To explore the effect of heparanase (HPSE) on apoptosis of microvascular endothelial cells (MVECs) and trans-endothelial migration of hepatocellular carcinoma (HCC) cells.

METHODS

A HCC cell line with high HPSE expression was selected by real-time quantitative PCR (qRT-PCR) and Western blotting and transefected with a lentiviral vector containing an interfering RNA sequence of HPSE. Transwell migration assay was performed to detect the trans-endothelial migration (TEM) rate of the transfected HCC cells across human umbilical vein endothelial cells (HUVECs). In a Transwell indirect co-culture system, the effect of HPSE silencing in the HCC cells was determined on apoptosis of HUVECs in vitro. A nude mouse model of HCC was used to verify the effect of HPSE on apoptosis of MVECs and liver metastasis of the tumor.

RESULTS

HCCLM3 cell line highly expressing HPSE was selected for the experiment. Transfection of the HCC cells with the lentiviral vector for HPSE interference the HCC cells resulted in significantly lowered TEM rate as compared with the cells transfected with the control vector (P &lt; 0.01). In the indirect co-culture system, the survival rate of HUVECs co-cultured with HCCLM3 cells with HPSE interference was significantly higher and their apoptotic index was significantly lower than those in the control group (P &lt; 0.05). Ultrastructural observation showed no obvious apoptosis of HUVECs co-cultured with HCCLM3 cells with HPSE interference but revealed obvious apoptotic changes in the control group. In the animal experiment, the tumor formation rate in the liver was 100% (6/6) in the control group, significantly higher than that in RNAi group (33.3%, 2/6) (P &lt; 0.05). Under optical microscope, necrosis and apoptosis of the MVECs was detected in the liver of the control mice, while the endothelial cells remained almost intact in RNAi group.

CONCLUSIONS

HPSE promotes the metastasis of HCC cells by inducing apoptosis of MVECs.

Inhibition of heparanase protects against pancreatic beta cell death in streptozotocin-induced diabetic mice via reducing intra-islet inflammatory cell infiltration

BACKGROUND AND PURPOSE

Intra-islet heparan sulfate (HS) plays an important role in the maintenance of pancreatic islet function. The aim of this study was to investigate the effect mechanism of HS loss on the functioning of islets in diabetic mice.

EXPERIMENTAL APPROACH

The hypoglycaemic effect of a heparanase inhibitor, OGT2115, was tested in a streptozotocin-induced diabetic mouse model. The islets in pancreatic sections were also stained to reveal their morphology. An insulinoma cell line (MIN6) and primary isolated murine islets were used to investigate the effect of OGT2115 in vitro.

KEY RESULTS

Intra-islet HS was clearly lost in streptozotocin-induced diabetic mice due to the increased heparanase expression in damaged islets. OGT2115 prevented intra-islet HS loss and improved the glucose profile and insulin secretion in streptozotocin-treated mice. The apoptosis of pancreatic beta cells and the infiltration of mononuclear macrophages, CD4- and CD8-positive T-cells in islets was reduced by OGT2115 in streptozotocin-treated mice, but OGT2115 did not alter the direct streptozotocin-induced damage in vitro. The expression of heparanase was increased in high glucose-treated isolated islets but not in response to direct streptozotocin stimulation. Further experiments showed that high glucose stimuli could decreased expression of PPARγ in cultured islets, thereby relieving the PPARγ-induced inhibition of heparanase gene expression.

CONCLUSION AND IMPLICATIONS

Hyperglycaemia could cause intra-islet HS loss by elevating the expression of heparanase, thereby aggravating inflammatory cell infiltration and islet damage. Inhibition of heparanase might provide benefit for pancreatic beta cell protection in Type 1 diabetes.

Loss of function of transcription factor EB remodels lipid metabolism and cell death pathways in the cardiomyocyte

Glucolipotoxicity following nutrient overload causes cardiomyocyte injury by inhibiting TFEB and suppressing lysosomal function. We ascertained whether in addition to the amount, the type of fatty acids (FAs) and duration of FA exposure regulate TFEB action and dictate cardiomyocyte viability. Saturated FA, palmitate, but not polyunsaturated FAs decreased TFEB content in a concentration- and time-dependent manner in cardiomyocytes. Hearts from high-fat high-sucrose diet-fed mice exhibited a temporal decline in nuclear TFEB content with marked elevation of diacylglycerol and triacylglycerol, suggesting that lipid deposition and TFEB loss are concomitant molecular events. Next, we examined the identity of signaling and metabolic pathways engaged by the loss of TFEB action in the cardiomyocyte. Transcriptome analysis in murine cardiomyocytes with targeted deletion of myocyte TFEB (TFEB^-/-) revealed enrichment of differentially expressed genes (DEG) representing pathways of nutrient metabolism, DNA damage and repair, cell death and cardiac function. Strikingly, genes involved in macroautophagy, mitophagy and lysosome function constituted a small portion of DEGs in TFEB^-/- cardiomyocytes. In myoblasts and/or myocytes, nutrient overload-induced lipid droplet accumulation and caspase-3 activation were exacerbated by silencing TFEB or attenuated by overexpressing constitutively active TFEB. The effect of TFEB overexpression were persistent in the presence of Atg7 loss-of-function, signifying that the effect of TFEB in the myocyte is independent of changes in the macroautophagy pathway. In the cardiomyocyte, the non-canonical effect of TFEB to reprogram energy metabolism is more evident than the canonical action of TFEB on lysosomal autophagy. Loss of TFEB function perturbs metabolic pathways in the cardiomyocyte and renders the heart prematurely susceptible to nutrient overload-induced injury.

Glycocalyx Degradation in Ischemia-Reperfusion Injury

The glycocalyx is a layer coating the luminal surface of vascular endothelial cells. It is vital for endothelial function as it participates in microvascular reactivity, endothelium interaction with blood constituents, and vascular permeability. Structural and functional damage to glycocalyx occurs in various disease states. A prominent clinical situation characterized by glycocalyx derangement is ischemia-reperfusion (I/R) of the whole body as well as during selective I/R to organs such as the kidney, heart, lung, or liver. Degradation of the glycocalyx is now considered a cornerstone in I/R-related endothelial dysfunction, which further impairs local microcirculation with a feed-forward loop of organ damage, due to vasoconstriction, leukocyte adherence, and activation of the immune response. Glycocalyx damage during I/R is evidenced by rising plasma levels of its principal constituents, heparan sulfate and syndecan-1. By contrast, the concentrations of these compounds in the circulation decrease after successful protective interventions in I/R, suggesting their use as surrogate biomarkers of endothelial integrity. In light of the importance of the glycocalyx in preserving endothelial cell integrity and its involvement in pathologic conditions, several promising therapeutic strategies to restore the damaged glycocalyx and to attenuate its deleterious consequences have been suggested. This review focuses on alterations of glycocalyx during I/R injury in general (to vital organs in particular), and on maneuvers aimed at glycocalyx recovery during I/R injury.