Vancomycin relieves tacrolimus-induced hyperglycemia by eliminating gut bacterial beta-glucuronidase enzyme activity

Up to 40% of transplant recipients treated long-term with tacrolimus (TAC) develop post-transplant diabetes mellitus (PTDM). TAC is an important risk factor for PTDM, but is also essential for immunosuppression after transplantation. Long-term TAC treatment alters the gut microbiome, but the mechanisms of TAC-induced gut microbiota in the pathogenesis of PTDM are poorly characterized. Here, we showed that vancomycin, an inhibitor of bacterial beta-glucuronidase (GUS), prevents TAC-induced glucose disorder and insulin resistance in mice. Metagenomics shows that GUS-producing bacteria are predominant and flourish in the TAC-induced hyperglycemia mouse model, with upregulation of intestinal GUS activity. Targeted metabolomics analysis revealed that in the presence of high GUS activity, the hydrolysis of bile acid (BAs)-glucuronic conjugates is increased and most BAs are overproduced in the serum and liver, which, in turn, activates the ileal farnesoid X receptor (FXR) and suppresses GLP-1 secretion by L-cells. The GUS inhibitor vancomycin significantly eliminated GUS-producing bacteria and inhibited bacterial GUS activity and BAs levels, thereby enhancing L-cell GLP-1 secretion and preventing hyperglycemia. Our results propose a novel clinical strategy for inhibiting the bacterial GUS enzyme to prevent hyperglycemia without requiring withdrawal of TAC treatment. This strategy exerted its effect through the ileal bile acid-FXR-GLP-1 pathway.

Opioid-induced microbial dysbiosis disrupts irinotecan (CPT-11) metabolism and increases gastrointestinal toxicity in a murine model

BACKGROUND AND PURPOSE

Opioids are commonly used for the management of cancer-associated pain and chemotherapy-induced diarrhoea. The chemotherapeutic irinotecan (CPT-11) causes severe gastrointestinal (GI) toxicity due to deconjugation of inactive metabolite SN-38 glucuronide (SN-38G) by bacterial β-glucuronidases to the active 7-ethyl-10-hydroxycamptothecin (SN-38). Opioids are known to cause gut microbial dysbiosis, this study evaluated whether CPT-11 anti-tumour efficacy and GI toxicity are exacerbated by opioid co-administration.

EXPERIMENTAL APPROACH

Eight-week-old C57BL/6 male mice were co-administration with CPT-11 ± opioid. 16S rRNA sequencing was used for gut microbiome analysis. LC-MS analyses of plasma and intestinal extracts were performed to investigate the pharmacokinetic profile of CPT-11. Histological analysis and quantitative real-time polymerase chain reaction were used to determine the severity of intestinal tissue damage. Human liver microsome In vitro assay was performed to confirm the effects of opioids on CPT-11 metabolism.

KEY RESULTS

Gut microbiome analysis showed that morphine treatment induced enrichment of β-glucuronidase-producing bacteria in the intestines of CPT-11-treated mice, resulting in SN-38 accumulation and exacerbation of GI toxicity in the small intestine. Oral administration of both antibiotics and glucuronidase inhibitor protected mice against GI toxicity induced with CPT-11 and morphine co-administration, implicating a microbiome-dependent mechanism. Additionally, morphine and loperamide decreased the plasma concentration of SN-38 and compromised CPT-11 anti-tumour efficacy, this seemed to be microbiome independent.

CONCLUSION AND IMPLICATIONS

Gut microbiota play a significant role in opioid and chemotherapeutic agent drug-drug interactions. Inhibition of gut microbial glucuronidase may also prevent adverse GI effects of CPT-11 in patients on opioids.

The role of gut microbial β-glucuronidase in drug disposition and development

Gut microbial β-glucuronidase (gmGUS) is involved in the disposition of many endogenous and exogenous compounds. Preclinical studies have shown that inhibiting gmGUS activity affects drug disposition, resulting in reduced toxicity in the gastrointestinal tract (GIT) and enhanced systemic efficacy. Additionally, manipulating gmGUS activity is expected to be effective in preventing/treating local or systemic diseases. Although results from animal studies are promising, challenges remain in developing drugs by targeting gmGUS. Here, we review the role of gmGUS in host health under physiological and pathological conditions, the impact of gmGUS on the disposition of phenolic compounds, models used to study gmGUS activity, and the perspectives and challenges in developing drugs by targeting gmGUS.

Gut microbiota activity in chickens from two genetic lines and with outdoor-preferring, moderate-preferring, and indoor-preferring ranging profiles

Despite the existing research into the gut microbiome of meat chickens, the associations between gut microbiome composition, its activity and chicken outdoor ranging frequency remain unexplored. The aim of this study was to determine the gut microbiota composition, activity and metabolic products in chickens of 2 different lines and 3 ranging profiles. Sixty non-beak trimmed birds, either Sasso or Green-legged Partridge were housed with access to outdoor ranges from wk. 5 to 10 of age. Outdoor ranges were video recorded to obtain frequencies of the birds’ range use. The information about relative abundance of selected bacterial groups in the ceca including Lactobacillus spp., E. coli, Bifidobacterium spp., and Clostridium spp. was obtained with the PCR method. Gut microbiota activity was assessed based on the glycolytic activity of bacterial enzymes including, α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and β-glucuronidase as well as based on the concentration of short-chain fatty acids (SCFA) in the caecal digesta. Statistical analysis was conducted by generalized linear mixed models, applying the breed and ranging profile as fixed effects and pen as a random factor. The lowest relative abundance of Bifidobacterium spp. was found in the cecal content of indoor-preferring Sasso birds (0.01 ± 0.001), as compared to all other birds in the experiment (ranging from 0.03 ± 0.01 to 0.11 ± 0.07; P = 0.0002). The lowest relative abundance of E. coli was identified for all outdoor-preferring birds and indoor- preferring Sasso birds (0.01 ± 0.001; P = 0.0087). Cecal activity of: α-glucosidase, β-glucuronidase and β-galactosidase was higher in Green-legged Partridges, as compared to Sasso (P = 0.013; P = 0.008; P = 0.004). Valeric acid concentrations were higher in moderate Green-legged Partridges than in Sasso of the same ranging profile (2.03 ± 0.16 vs. 1.5 ± 0.17; 0.016). The majority of the current results confirmed an effect of genotype and ranging profile on the various analyzed parameters. In outdoor-preferring birds, the consumption of pasture originating feed sources as a supplement to the indoor accessible cereal-based diet likely caused the positive effects on the birds’ microbial profile.

Antiinflammatory Actions of Klotho: Implications for Therapy of Diabetic Nephropathy

Klotho was initially introduced as an antiaging molecule. Klotho deficiency significantly reduces lifespan, and its overexpression extends it and protects against various pathological phenotypes, especially renal disease. It was shown to regulate phosphate and calcium metabolism, protect against oxidative stress, downregulate apoptosis, and have antiinflammatory and antifibrotic properties. The course of diabetes mellitus and diabetic nephropathy resembles premature cellular senescence and causes the activation of various proinflammatory and profibrotic processes. Klotho was shown to exert many beneficial effects in these disorders. The expression of Klotho protein is downregulated in early stages of inflammation and diabetic nephropathy by proinflammatory factors. Therefore, its therapeutic effects are diminished in this disorder. Significantly lower urine levels of Klotho may serve as an early biomarker of renal involvement in diabetes mellitus. Recombinant Klotho administration and Klotho overexpression may have immunotherapeutic potential for the treatment of both diabetes and diabetic nephropathy. Therefore, the current manuscript aims to characterize immunopathologies occurring in diabetes and diabetic nephropathy, and tries to match them with antiinflammatory actions of Klotho. It also gives reasons for Klotho to be used in diagnostics and immunotherapy of these disorders.

Ameliorating Effect of Klotho Protein on Rat Heart during I/R Injury

An essential procedure for the treatment of myocardial infarction is restoration of blood flow in the obstructed infarct artery, which may cause ischaemia/reperfusion (I/R) injury. Heart I/R injury manifests in oxidative stress, metabolic and morphological disorders, or cardiac contractile dysfunction. Klotho protein was found to be produced in the heart tissue and participate in antioxidation or ion homeostasis. The aim of this study was to examine an influence of Klotho protein on the heart subjected to I/R injury. Wistar rats served as a surrogate heart model ex vivo. Rat hearts perfused using the Langendorff method were subjected to global no-flow ischaemia, and isolated rat cardiomyocytes underwent chemical I/R in vitro, with or without recombinant Klotho protein administration. Haemodynamic parameters of heart function, cell contractility, markers of I/R injury and oxidative stress, and the level of contractile proteins such as myosin light chain 1 (MLC1) and troponin I (TnI) were measured. The treatment of hearts subjected to I/R injury with Klotho protein resulted in a recovery of heart mechanical function and ameliorated myocyte contractility. This improvement was associated with decreased tissue injury, enhanced antioxidant capacity, and reduced release of MLC1 and TnI. The present research showed the contribution of Klotho to cardioprevention during I/R. Thus, Klotho protein may support the protection from I/R injury and prevention of contractile dysfunction in the rat heart.

Klotho restrain RIG-1/NF-κB signaling activation and monocyte inflammatory factor release under uremic condition

AIMS

Systemic inflammation is a main hallmark of chronic kidney disease (CKD), but the underlying mechanisms of pathogenesis of CKD-associated systemic inflammation is unclear. Current study was designed to investigate the relationship between indoxyl sulphate (IS) and CKD-associated systemic inflammation along with the protective effects of Klotho in CKD.

METHODS

IS serum levels from patients were detected by high-performance liquid chromatography (HPLC), and Serum Klotho, IL-6 and TNF-α were measured separately by ELISA and Real-Time PCR analysis. Monocytes were incubated with or without Klotho, while the expressions of retinoic acid-inducible gene I (RIG-I) and NF-κB were analyzed through Western blot assay. Heterozygous kl/kl (kl/+) mice or WT mice were treated with 5/6 renal damage. Thereafter, the CKD mice were intraperitoneally injected with recombinant Klotho protein or PBS.

KEY FINDINGS

It shows that in 286 CKD patients, the serum levels of inflammatory factors were positively related with IS, but negatively related with Klotho. Klotho significantly inhibited IS-induced RIG-I/NF-κB activation and productions of both IL-6 and TNF-α in cultured monocytes. In vivo, along with the increase of IS and decrease of Klotho in the serum, the activation of RIG-I/NF-κB signaling was observed in peripheral blood monocytes in both CKD mice and patients. Notably, higher levels of IL-6 and TNF-α were detected in kl+/- mice given CKD. Klotho administration has evidently attenuated RIG-I/NF-κB activation in monocytes and systemic inflammation in CKD mice.

SIGNIFICANCE

The findings suggest that Klotho can suppress CKD-associated systemic inflammation through inhibiting IS-induced RIG-1/NF-κB activation and monocyte inflammatory factor release.

Vestronidase Alfa: A Review in Mucopolysaccharidosis VII

Mucopolysaccharidosis VII is an extremely rare, autosomal recessive lysosomal storage disorder characterized by a deficiency of β-glucuronidase activity, resulting in partial degradation and accumulation of GAGs in numerous tissues throughout the body, with consequent cellular damage and organ dysfunction. Enzyme replacement therapy (ERT) with intravenous vestronidase alfa (Mepsevii™), a recombinant form of human β-glucuronidase, is the first disease-specific therapy approved for the treatment of mucopolysaccharidosis VII in pediatric and adult patients. In the pivotal, blind start, phase 3 trial, 24 weeks of vestronidase alfa therapy significantly reduced urinary GAG (uGAG) excretion in patients with mucopolysaccharidosis VII. Based on a Multi-Domain Responder Index (MDRI; comprises six clinically important morbidity domains, with prespecified minimally important differences for each domain), most evaluable patients experienced an improvement in ≥ 1 domain during the 24-week primary assessment period (overall positive mean change of 0.5 domains). The clinical benefits of vestronidase alfa were sustained during longer-term treatment, as was the reduction in uGAG excretion. Vestronidase alfa has a manageable tolerability profile, with most adverse reactions of mild to moderate severity. Given the lack of treatment options and the clinical benefits it provides, intravenous vestronidase alfa is an important emerging ERT for patients with mucopolysaccharidosis VII.

Role of fibroblast growth factor 23 and klotho cross talk in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia that mainly affects the elderly. Several reports have demonstrated that aging is involved in the underlying pathogenic mechanisms of IPF. α-Klotho (KL) has been well characterized as an "age-suppressing" hormone and can provide protection against cellular senescence and oxidative stress. In this study, KL levels were assessed in human plasma and primary lung fibroblasts from patients with idiopathic pulmonary fibrosis (IPF-FB) and in lung tissue from mice exposed to bleomycin, which showed significant downregulation when compared with controls. Conversely, transgenic mice overexpressing KL were protected against bleomycin-induced lung fibrosis. Treatment of human lung fibroblasts with recombinant KL alone was not sufficient to inhibit transforming growth factor-β (TGF-β)-induced collagen deposition and inflammatory marker expression. Interestingly, fibroblast growth factor 23 (FGF23), a proinflammatory circulating protein for which KL is a coreceptor, was upregulated in IPF and bleomycin lungs. To our surprise, FGF23 and KL coadministration led to a significant reduction in fibrosis and inflammation in IPF-FB; FGF23 administration alone or in combination with KL stimulated KL upregulation. We conclude that in IPF downregulation of KL may contribute to fibrosis and inflammation and FGF23 may act as a compensatory antifibrotic and anti-inflammatory mediator via inhibition of TGF-β signaling. Upon restoration of KL levels, the combination of FGF23 and KL leads to resolution of inflammation and fibrosis. Altogether, these data provide novel insight into the FGF23/KL axis and its antifibrotic/anti-inflammatory properties, which opens new avenues for potential therapies in aging-related diseases like IPF.

Klotho Ameliorates Medullary Fibrosis and Pressure Natriuresis in Hypertensive Rat Kidneys

Renal expression of klotho is reduced in hypertension. Experiments were performed to examine whether exogenous klotho protein supplementation ameliorates pressure natriuresis in early phase of hypertension, using stroke-prone spontaneously hypertensive rats (sp-SHR). The interactions between klotho protein and renal renin-Ang (angiotensin) system were examined with immunoprecipitation and cell culture methods. Uninephrectomy was performed in sp-SHRs to induce nephrosclerosis, and they were treated with exogenous klotho protein or vehicle. Exogenous klotho protein supplementation to sp-SHR decreased blood pressure, renal Ang II levels, AGT (angiotensinogen) expression, HIF (hypoxia-inducible factor)-1α abundance, and medullary fibronectin levels, with increased renal klotho expression and serum and urine klotho levels. Klotho supplementation also reduced kidney weight, renal phosphorylated Akt, and mTOR (mammalian target of rapamycin) abundance. Furthermore, klotho supplementation restored renal autoregulation of glomerular filtration rate and enhanced pressure-induced natriuresis in sp-SHR. Klotho protein bound to AT1R (Ang II type-1 receptor) and decreased the presence of AT1R on HK-2 (human proximal tubular) cells, attenuating inositol triphosphate generation. Klotho protein suppressed Ang II-induced increments of AGT expression in HK-2 cells. Collectively, the present data demonstrate that klotho binds with the AT1R to suppress Ang signal transduction, participating in inactivating renal renin-Ang system. Our results also suggest that exogenous klotho supplementation represses Akt-mTOR signaling to reduce renal hypertrophy and restore the autoregulatory ability of glomerular filtration rate in uninephrectomized sp-SHRs. Finally, the present findings implicate that klotho supplementation inhibits HIF-1α pathway and medullary fibrosis, contributing to enhancements of pressure natriuresis and reduction in blood pressure.

Effect of osthole on advanced glycation end products-induced renal tubular hypertrophy and role of klotho in its mechanism of action

BACKGROUND

Osthole has been widely reported to have pharmacological activities such as anti-cancer, anti-inflammation and anti-hyperlipidemic effects. Klotho was identified as an anti-senescence protein in a variety of tissues. Loss of klotho has been associated with chronic kidney disease. However, potential roles and molecular events for osthole and klotho in diabetic nephropathy remain unclear.

PURPOSE

In the current study, we undertook to study the effect of osthole on klotho expression in advanced glycation end products (AGE)-cultured human renal proximal tubular cells, and to investigate the molecular mechanisms of osthole and exogenous klotho against AGE-induced renal tubular hypertrophy.

METHODS

Cell viability was elucidated by MTT assay. Protein expression was measured by Western blotting. mRNA level was analyzed by real-time PCR. Cellular hypertrophy growth was evaluated by hypertrophy index. Relative cell size was detected by flow cytometry.

RESULTS

We found that raising the ambient AGE concentration causes a dose-dependent decrease in klotho synthesis. Osthole significantly increased AGE-inhibited klotho mRNA and protein expression. Osthole and exogenous klotho treatments significantly attenuated AGE-induced Janus kinase 2 (JAK2)-signal transducers and activators of transcription 1 (STAT1) and STAT3 activation. Moreover, protein levels of suppressor of cytokine signaling 1 (SOCS1) and SOCS3 were augmented by osthole and exogenous klotho. The abilities of osthole and exogenous klotho to reverse AGE-induced cellular hypertrophy were verified by the observation that osthole and exogenous klotho inhibited p21^Waf1/Cip1/collagen IV/RAGE expression, total protein content, and cell size.

CONCLUSION

Consequently, we found that osthole attenuated AGE-induced renal tubular hypertrophy via induction of klotho expression and suppression of the JAK2-STAT1/STAT3 signaling. These results also showed that klotho might be used as a unique molecular target for the treatment of diabetic nephropathy.

Soluble Klotho causes hypomineralization in Klotho-deficient mice

The type I transmembrane protein αKlotho (Klotho) serves as a coreceptor for the phosphaturic hormone fibroblast growth factor 23 (FGF23) in kidney, while a truncated form of Klotho (soluble Klotho, sKL) is thought to exhibit multiple activities, including acting as a hormone, but whose mode(s) of action in different organ systems remains to be fully elucidated. FGF23 is expressed primarily in osteoblasts/osteocytes and aberrantly high levels in the circulation acting via signaling through an FGF receptor (FGFR)-Klotho coreceptor complex cause renal phosphate wasting and osteomalacia. We assessed the effects of exogenously added sKL on osteoblasts and bone using Klotho-deficient (kl/kl) mice and cell and organ cultures. sKL induced FGF23 signaling in bone and exacerbated the hypomineralization without exacerbating the hyperphosphatemia, hypercalcemia and hypervitaminosis D in kl/kl mice. The same effects were seen in rodent bone models in vitro, in which we also detected formation of a sKL complex with FGF23-FGFR and decreased Phex (gene responsible for X-linked hypophosphatemic rickets (XLH)/osteomalacia) expression. Further, sKL-FGF23-dependent hypomineralization in vitro was rescued by soluble PHEX. These data suggest that exogenously added sKL directly participates in FGF23 signaling in bone and that PHEX is a downstream effector of the sKL-FGF23-FGFR axis in bone.

Upregulation of Klotho potentially inhibits pulmonary vascular remodeling by blocking the activation of the Wnt signaling pathway in rats with PM2.5-induced pulmonary arterial hypertension

We evaluated the effects of Klotho on pulmonary vascular remodeling and cell proliferation and apoptosis in rat models with PM2.5-induced pulmonary arterial hypertension (PAH) via the Wnt signaling pathway. After establishing rat models of PM2.5-induced PAH, these Sprague-Dawley male rats were randomized into control and model groups. Cells extracted from the model rats were sub-categorized into different groups. Activation of Wnt/β-catenin signaling transcription factor was detected by a TOPFlash/FOPFlash assay. A serial of experiment was conducted to identify the mechanism of Klotho on PHA via the Wnt signaling pathway. VEGF levels and PaCO₂ content were higher in the model group, while PaO_2, NO₂^- /NO₃^- content and Klotho level was lower compared to the control group. In comparison to the control group, the model group had decreased Klotho and Bax levels, and elevated Wnt-1, β-catenin, bcl-2, survivin, and PCNA expression, VEGF, IL-6, TNF-α, TNF-β1, and bFGF levels, as well as the percentage of pulmonary artery ring contraction. The Klotho vector, DKK-1 and DKK-1 + Klotho vector groups exhibited reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as shortened S phase compared with the blank and NC groups. Compared with the Klotho vector and DKK-1 groups, the DKK-1 + Klotho vector groups had reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as a shortened S phase. Conclusively, Klotho inhibits pulmonary vascular remodeling by inactivation of Wnt signaling pathway.

Klotho ameliorates hydrogen peroxide-induced oxidative injury in TCMK-1 cells

PURPOSE

Defects in Klotho gene expression in mice result in a vulnerability to oxidative injuries. We aimed to identify the expression of Klotho in a mouse tubular epithelial (TCMK-1) cell line, and also to investigate changes in Klotho expression induced by oxidative stress and the potential role of intra- and extracellular Klotho protein.

METHODS

During exposure to hydrogen peroxide (H₂O₂), an overexpression of the Klotho gene was induced and exogenous Klotho protein was added in TCMK-1 cells. The generation of reactive oxidative species (ROS) was examined by flow cytometry, and cell viability was assessed by Cell Counting Kit-8. Cellular apoptosis was determined by flow cytometry and Hoechst 33258 staining followed by Western blotting to evaluate the expression of Klotho, antioxidant enzymes, and apoptosis-associated proteins.

RESULTS

While H₂O₂ significantly suppressed Klotho expression, cell viability, and the expression of antioxidant enzymes in a concentration-dependent manner, cellular apoptosis was increased and p38/MAPK and JNK/MAPK were activated. Intra- and extracellular Klotho remarkably ameliorated viability inhibition, ROS generation, and cellular apoptosis induced by H₂O₂. Intra- and extracellular Klotho also reversed the loss of antioxidant enzymes, the elevation of cleaved Caspase-3 and Bax/Bcl-2, and the phosphorylation of JNK/MAPK and p38/MAPK.

CONCLUSIONS

Klotho has posed antioxidant and anti-apoptotic effects on oxidative injuries in TCMK-1 cells, which might be partially related to its inhibition of JNK/MAPK and p38/MAPK phosphorylation and subsequent elevation of antioxidant enzymes. Increasing Klotho expression has played a protective role against oxidative stress in tubular epithelial cells.

Peripheral Elevation of a Klotho Fragment Enhances Brain Function and Resilience in Young, Aging, and α-Synuclein Transgenic Mice

Cognitive dysfunction and decreased mobility from aging and neurodegenerative conditions, such as Parkinson and Alzheimer diseases, are major biomedical challenges in need of more effective therapies. Increasing brain resilience may represent a new treatment strategy. Klotho, a longevity factor, enhances cognition when genetically and broadly overexpressed in its full, wild-type form over the mouse lifespan. Whether acute klotho treatment can rapidly enhance cognitive and motor functions or induce resilience is a gap in our knowledge of its therapeutic potential. Here, we show that an α-klotho protein fragment (αKL-F), administered peripherally, surprisingly induced cognitive enhancement and neural resilience despite impermeability to the blood-brain barrier in young, aging, and transgenic α-synuclein mice. αKL-F treatment induced cleavage of the NMDAR subunit GluN2B and also enhanced NMDAR-dependent synaptic plasticity. GluN2B blockade abolished αKL-F-mediated effects. Peripheral αKL-F treatment is sufficient to induce neural enhancement and resilience in mice and may prove therapeutic in humans.

Inhibition of TRPC6 channels ameliorates renal fibrosis and contributes to renal protection by soluble klotho

Fibrosis is an exaggerated form of tissue repair that occurs with serious damage or repetitive injury and ultimately leads to organ failure due to the excessive scarring. Increased calcium ion entry through the TRPC6 channel has been associated with the pathogenesis of heart and glomerular diseases, but its role in renal interstitial fibrosis is unknown. We studied this by deletion of Trpc6 in mice and found it decreased unilateral ureteral obstruction-induced interstitial fibrosis and blunted increased mRNA expression of fibrosis-related genes in the ureteral obstructed kidney relative to that in the kidney of wild-type mice. Administration of BTP2, a pyrazol derivative known to inhibit function of several TRPC channels, also ameliorated obstruction-induced renal fibrosis and gene expression in wild-type mice. BTP2 inhibited carbachol-activated TRPC3 and TRPC6 channel activities in HEK293 cells. Ureteral obstruction caused over a 10-fold increase in mRNA expression for TRPC3 as well as TRPC6 in the kidneys of obstructed relative to the sham-operated mice. The magnitude of protection against obstruction-induced fibrosis in Trpc3 and Trpc6 double knockout mice was not different from that in Trpc6 knockout mice. Klotho, a membrane and soluble protein predominantly produced in the kidney, is known to confer protection against renal fibrosis. Administration of soluble klotho significantly reduced obstruction-induced renal fibrosis in wild-type mice, but not in Trpc6 knockout mice, indicating that klotho and TRPC6 inhibition act in the same pathway to protect against obstruction-induced renal fibrosis. Thus klotho and TRPC6 may be pharmacologic targets for treating renal fibrosis.

Inflammation-associated extracellular β-glucuronidase alters cellular responses to the chemical carcinogen benzo[a]pyrene

Neutrophils infiltrate tissues during inflammation, and when activated, they release β-glucuronidase. Since inflammation is associated with carcinogenesis, we investigated how extracellular β-glucuronidase changed the in vitro cellular response to the chemical carcinogen benzo(a)pyrene (B[a]P). For this we exposed human liver (HepG2) and lung (A549) cells to B[a]P in the presence or absence of β-glucuronidase. β-Glucuronidase reduced B[a]P-induced expression of CYP1A1 and CYP1B1 at 6 h after exposure, which did not depend on β-glucuronidase activity, because the inhibitor D-saccharic acid 1,4-lactone monohydrate did not antagonize the effect of β-glucuronidase. On the other hand, the inhibitory effect of β-glucuronidase on CYP expression was dependent on signalling via the insulin-like growth factor receptor (IGF2R, a known receptor for β-glucuronidase), because co-incubation with the IGF2R inhibitor mannose-6-phosphate completely abolished the effect of β-glucuronidase. Extracellular β-glucuronidase also reduced the formation of several B[a]P metabolites and B[a]P-DNA adducts. Interestingly, at 24 h of exposure, β-glucuronidase significantly enhanced CYP expression, probably because β-glucuronidase de-glucuronidated B[a]P metabolites, which continued to trigger the aryl hydrocarbon receptor (Ah receptor) and induced expression of CYP1A1 (in both cell lines) and CYP1B1 (in A549 only). Consequently, significantly higher concentrations of B[a]P metabolites and DNA adducts were found in β-glucuronidase-treated cells at 24 h. DNA adduct levels peaked at 48 h in cells that were exposed to B[a]P and treated with β-glucuronidase. Overall, these data show that β-glucuronidase alters the cellular response to B[a]P and ultimately enhances B[a]P-induced DNA adduct levels.

Heparanase Activates Antithrombin through the Binding to Its Heparin Binding Site

Heparanase is an endoglycosidase that participates in morphogenesis, tissue repair, heparan sulphates turnover and immune response processes. It is over-expressed in tumor cells favoring the metastasis as it penetrates the endothelial layer that lines blood vessels and facilitates the metastasis by degradation of heparan sulphate proteoglycans of the extracellular matrix. Heparanase may also affect the hemostatic system in a non-enzymatic manner, up-regulating the expression of tissue factor, which is the initiator of blood coagulation, and dissociating tissue factor pathway inhibitor on the cell surface membrane of endothelial and tumor cells, thus resulting in a procoagulant state. Trying to check the effect of heparanase on heparin, a highly sulphated glycosaminoglycan, when it activates antithrombin, our results demonstrated that heparanase, but not proheparanase, interacted directly with antithrombin in a non-covalent manner. This interaction resulted in the activation of antithrombin, which is the most important endogenous anticoagulant. This activation mainly accelerated FXa inhibition, supporting an allosteric activation effect. Heparanase bound to the heparin binding site of antithrombin as the activation of Pro41Leu, Arg47Cys, Lys114Ala and Lys125Alaantithrombin mutants was impaired when it was compared to wild type antithrombin. Intrinsic fluorescence analysis showed that heparanase induced an activating conformational change in antithrombin similar to that induced by heparin and with a KD of 18.81 pM. In conclusion, under physiological pH and low levels of tissue factor, heparanase may exert a non-enzymatic function interacting and activating the inhibitory function of antithrombin.

The Effect of Klotho Treatment on Atherogenesis, Blood Pressure, and Metabolic Parameters in Experimental Rodent Models

Klotho is a transmembrane protein, expressed mainly in the kidneys and the choroid plexus. The extracellular domain of klotho is composed of 2 internal repeats, KL1 and KL2, which can be cleaved and act as hormones. Klotho-deficient mice develop a phenotype resembling human aging. Laboratory and clinical data suggest a favorable effect of klotho on atherosclerosis, high blood pressure, and metabolic syndrome. Therefore, we aimed to study the effect of klotho treatment on atherogenesis, blood pressure, and metabolic parameters in experimental rodent models. Fructose-fed Sprague-Dawley rats (metabolic syndrome model) and apolipoprotein E (apoE -/-) knock-out mice (atherosclerosis model) were treated with either klotho or its active domain KL1. In apoE -/- mice, klotho unexpectedly elevated plasma cholesterol and triglyceride levels compared to the control group. Yet, it did not increase the aortic sinus atherosclerotic lesion area. In fructose-fed Sprague-Dawley rats, klotho treatment did not lower blood pressure or plasma triglyceride levels. Although KL1 treatment did not lower blood pressure or plasma insulin levels, it significantly reduced the elevation of total plasma triglyceride levels (from 2.3-fold to 1.6-fold, p<0.05) due to lower triglyceride-rich VLDL levels. Klotho did not show any beneficial effects on atherosclerosis and components of the metabolic syndrome and was associated with increased plasma cholesterol levels. On the other hand, treatment with KL1 may lower plasma triglyceride levels independent of insulin. Additional studies are required in order to decipher the complex role of klotho and its active domains in the regulation of plasma lipid levels.

[Effect of 1,3-O,N spiroheterocyclic inhibitors of heparanase on the growth of HeLa cells]

OBJECTIVE

To provide the theoretical supportting for targeted heparanase (HPA) inhibition of cervical cancer through observing the anti-proliferative effect of the HPA inhibitor on HeLa cell line of cervical cancer.

METHODS

The two series of 13 kinds of novel HPA inhibitors were synthesized and optimized. Heparan degrading enzyme assay kit was used to test the effect of the inhibitors on the inhibition of HPA enzyme activity. Methyl thiazolyl tetrazolium (MTT) method and scratch test were used to observe the anti-proliferative and the migration effect of the inhibitors on HeLa cells. Flow cytometry was performed to determine the cell cycles and apoptosis. The expression of HPA was evaluated by reverse transcription (RT)-PCR, western blot and immunocytochemistry.

RESULTS

All tested inhibitors could inhibit the activity of HPA enzyme [the range of 50% inhibiting concentration (IC50) values from 4.47 to 47.19 µmol/L] and the growth of HeLa cells (the range of IC50 values from 48.16 to 96.64 µmol/L). Among them, No.16 compound exhibits the strongest inhibition against the growth of HeLa, which could arrest the cell into G0/G1 and G2/M phases. The rate of cell apoptosis in the group treated with 50 µmol/L No.16 for 48 hours [(11.9 ± 1.2)%] was significantly higher than that [(6.6 ± 1.8)%] in untreated group (P = 0.013). Real time PCR and western blot showed that expression levels of HPA mRNA (1.23 ± 0.46) and protein (0.46 ± 0.31) significantly decreased in the treated group as compared with the levels of HPA mRNA (3.43 ± 0.45) and protein (1.30 ± 0.58) in the untreated group (both P < 0.05). Immunocytochemistry also showed that the treatment of No.16 significantly reduced the average optical density (0.39 ± 0.04) of HPA immuostaining signal compared with that in the control group (0.50 ± 0.09; P = 0.026).

CONCLUSION

Novel 1,3-O,N spiroheterocyclic HPA inhibitors could inhibit the proliferation of HeLa cells, inhibit the HPA enzyme activity in different degree, and downregulate the expression of HPA protein.

Heparanase stimulates chondrogenesis and is up-regulated in human ectopic cartilage: a mechanism possibly involved in hereditary multiple exostoses

Hereditary multiple exostoses is a pediatric skeletal disorder characterized by benign cartilaginous tumors called exostoses that form next to growing skeletal elements. Hereditary multiple exostoses patients carry heterozygous mutations in the heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2, but studies suggest that EXT haploinsufficiency and ensuing partial HS deficiency are insufficient for exostosis formation. Searching for additional pathways, we analyzed presence and distribution of heparanase in human exostoses. Heparanase was readily detectable in most chondrocytes, particularly in cell clusters. In control growth plates from unaffected persons, however, heparanase was detectable only in hypertrophic zone. Treatment of mouse embryo limb mesenchymal micromass cultures with exogenous heparanase greatly stimulated chondrogenesis and bone morphogenetic protein signaling as revealed by Smad1/5/8 phosphorylation. It also stimulated cell migration and proliferation. Interfering with HS function both with the chemical antagonist Surfen or treatment with bacterial heparitinase up-regulated endogenous heparanase gene expression, suggesting a counterintuitive feedback mechanism that would result in further HS reduction and increased signaling. Thus, we tested a potent heparanase inhibitor (SST0001), which strongly inhibited chondrogenesis. Our data clearly indicate that heparanase is able to stimulate chondrogenesis, bone morphogenetic protein signaling, cell migration, and cell proliferation in chondrogenic cells. These properties may allow heparanase to play a role in exostosis genesis and pathogenesis, thus making it a conceivable therapeutic target in hereditary multiple exostoses.

Signals mediating Klotho-induced neuroprotection in hippocampal neuronal cells

The erythropoietin (Epo) receptor (EpoR) is expressed in the brain and was shown to have neuroprotective effects against brain damage in animal models. A recent study indicated that EpoR and its activity are the downstream effectors of Klotho for cytoprotection in the kidney. Thus, we propose that Klotho can stimulate the expression of EpoR in neuronal cells to enhance Epo-mediated protection. H19-7 hippocampal neuronal cells were treated with recombinant Klotho. In H19-7 cells, Klotho increased the expression of both the EpoR protein and mRNA. Klotho also enhanced the transcription activity of the EpoR promoter in H19-7 cells. Moreover, Klotho augmented the Epo-triggered phosphorylation of Jak2 and Stat5 and protected H19-7 cells from hydrogen peroxide cytotoxicity. The silencing of EpoR abolished the protective effect of Klotho against peroxide-induced cytotoxicity. Finally, the silencing of GATA1 diminished the Klotho-induced increase in EpoR protein and mRNA expression as well as its promoter activity. In conclusion, Klotho increased EpoR expression in neuronal cells through GATA1, thereby enabling EpoR to function as a cytoprotective protein against oxidative injury.

Simultaneous Determination of Isoflavones and Bisphenol A in Rat Serum by High-performance Liquid Chromatography Coupled with Coulometric Array Detection

A method for simultaneous detection and quantification is presented to determine the presence of isoflavones and bisphenol A in a biological sample. A coulometric array detector was used with reversed-phase high-performance liquid chromatography (HPLC). Daidzein (1), glycitein (2), genistein (3) and their glucoside conjugates, daidzin (4), glycitin (5) and genistin (6), were measured as phytochemicals. Also assayed here was equol (7), a metabolite from compound 1, and bisphenol A (8), an industrial chemical that acts as an endocrine disrupter. All chemicals were simultaneously detected by using a 600-mV single detection voltage with high efficacy. A mixture of 1, 3 and 8 was orally administered to rats, and the levels of these three chemicals in the serum were clearly increased after a 4 kU beta-glucuronidase treatment. The levels of compounds 1 and 3 in the serum were detected at 1665 and 2040 ng/ml, while 8 was at a low level of 417 ng/ml. Compound 7 in the serum was not detected until after enzymatic hydrolysis (72 ng/ml). These results suggest that this analytical method would be useful for metabolic and pharmacokinetic studies on isoflavones and bisphenol A.

Immunomodulatory effect of Stichopus japonicus acid mucopolysaccharide on experimental hepatocellular carcinoma in rats

Stichopus japonicus acid mucopolysaccharide (SJAMP) is an important biologically active compound that can be extracted from the body wall of the sea cucumber. The present study investigated the anti-tumor and immunomodulatory effects of SJAMP in an experimental hepatocellular carcinoma (HCC) model in rats. Three doses of SJAMP (17.5 mg/kg, 35 mg/kg, and 70 mg/kg administered 5 days/week via oral gavage) were given to rats with diethylnitrosamine (DEN)-induced HCC. SJAMP treatment significantly inhibited DEN-induced HCC by reducing both the number and mean volume of nodules, decreasing serum a-fetoprotein (AFP) levels and proliferating cell nuclear antigen (PCNA) expression in liver, and increasing p21 expression. Furthermore, SJAMP decreased the serum levels of ALT, AST, GGT and TNF-α and increased serum IL-2. SJAMP administration also improved indices of spleen and thymus function and improved both macrophage phagocytosis and NK cell-mediated tumoricidal activity. Moreover, CD3+ and CD4+ T lymphocyte levels recovered significantly and the CD4+/CD8+ T cell ratio normalized in a dose-dependent manner. In conclusion, SJAMP effectively inhibited the growth of HCC through the stimulation of immune organs and tissue proliferation, leading to the enhancement of cellular immunity pathways in rats.

Fibroblast growth factor 23 (FGF23) and alpha-klotho stimulate osteoblastic MC3T3.E1 cell proliferation and inhibit mineralization

Elevated serum levels of the phosphate-regulating hormone fibroblast growth factor 23 (FGF23) are found in patients with phosphate wasting diseases and chronic kidney disease-mineral and bone disorder (CKD-MBD). These diseases are associated with rickets and renal osteodystrophy, respectively. FGF23 is secreted from osteoblastic cells and signals through FGFRs, membrane coreceptor alpha-Klotho (Klotho), and, possibly, a circulating form of Klotho. Despite the absence of detectable Klotho on osteoblastic cells, studies have suggested that forced FGF23 expression in osteoblasts inhibited mineralization. Thus, we examined the effects of exogenously applied FGF23 on osteoblastic MC3T3.E1 cell proliferation and differentiation, with and without soluble Klotho. MC3T3.E1 cells were cultured in osteoblast differentiation medium, supplemented with FGF23 (0.1-1,000 ng/mL), Klotho (50 ng/mL), the combination FGF23 + Klotho, and FGF2 (100 ng/mL) as a control. Neither FGF23 nor Klotho exposure affected proliferation of day 4 growth phase cells or mineralization of day 14 cultures. In contrast, FGF23 + Klotho resulted in inhibition of mineralization and osteoblast activity markers at day 14, and a slight, reproducible induction of proliferation. Inhibition of FGFR1, but not FGFR2 or FGFR3, completely restored FGF23 + Klotho-induced inhibition of alkaline phosphatase (ALP) activity at day 7. ALP activity was partially restored by the MAPK inhibitor U0126 but not inhibitors p38 and P13K. Thus, soluble Klotho enables FGF23 signaling in MC3T3.E1 cells, likely through FGFR 1(IIIc). Elevated FGF23 actions, in part, appear to parallel FGF2 with lower potency. In addition to affecting bone via indirect phosphate wasting pathways, supraphysiological FGF23 and soluble Klotho may directly impact bone in diseases with elevated FGF23 levels.

Transgene expression and transgene-induced silencing in diploid and autotetraploid Arabidopsis

Previous studies have suggested that transgene expression in plants can be affected by ploidy. Here we show that three different transgenes, a reporter transgene, an antisense transgene, and a hairpin RNA (hpRNA) transgene, are all expressed at a lower level in autotetraploid (4n) than in diploid (2n) Arabidopsis. RNA silencing of two endogenous genes was induced by the antisense and hpRNA transgenes and this silencing is significantly less effective in 4n than in 2n Arabidopsis; furthermore, the reduced silencing in 4n Arabidopsis correlated with reduced accumulation of silencing-inducer RNAs. Methylation analysis both of independent 2n and 4n transgenic lines and of 2n and 4n progeny derived from the same 3n transgenic parent, indicated that transgenes are more methylated in 4n than 2n Arabidopsis. These results suggest that transgenes are transcriptionally repressed in the 4n background, resulting in expression levels lower than in the 2n background. Transgenes designed to silence endogenous genes express lower concentrations of silencing-inducer RNAs in 4n Arabidopsis plants, resulting in less effective silencing of target genes than in 2n Arabidopsis plants.

Alleviating cancer drug toxicity by inhibiting a bacterial enzyme

The dose-limiting side effect of the common colon cancer chemotherapeutic CPT-11 is severe diarrhea caused by symbiotic bacterial β-glucuronidases that reactivate the drug in the gut. We sought to target these enzymes without killing the commensal bacteria essential for human health. Potent bacterial β-glucuronidase inhibitors were identified by high-throughput screening and shown to have no effect on the orthologous mammalian enzyme. Crystal structures established that selectivity was based on a loop unique to bacterial β-glucuronidases. Inhibitors were highly effective against the enzyme target in living aerobic and anaerobic bacteria, but did not kill the bacteria or harm mammalian cells. Finally, oral administration of an inhibitor protected mice from CPT-11-induced toxicity. Thus, drugs may be designed to inhibit undesirable enzyme activities in essential microbial symbiotes to enhance chemotherapeutic efficacy.

Heparanase promotes engraftment and prevents graft versus host disease in stem cell transplantation

Background

Heparanase, endoglycosidase that cleaves heparan sulfate side chains of heparan sulfate proteoglycans, plays important roles in cancer metastasis, angiogenesis and inflammation.

Design and Methods

Applying a mouse model of bone marrow transplantation and transgenic mice over-expressing heparanase, we evaluated the effect of heparanase on the engraftment process and the development of graft-versus-host disease.

Results

Analysis of F1 mice undergoing allogeneic bone marrow transplantation from C57BL/6 mice demonstrated a better and faster engraftment in mice receiving cells from donors that were pretreated with heparanase. Moreover, heparanase treated recipient F1 mice showed only a mild appearance of graft-versus-host disease and died 27 days post transplantation while control mice rapidly developed signs of graft-versus-host disease (i.e., weight loss, hair loss, diarrhea) and died after 12 days, indicating a protective effect of heparanase against graft-versus-host disease. Similarly, we applied transgenic mice over-expressing heparanase in most tissues as the recipients of BMT from C57BL/6 mice. Monitoring clinical parameters of graft-versus-host disease, the transgenic mice showed 100% survival on day 40 post transplantation, compared to only 50% survival on day 14, in the control group. In vitro and in vivo studies revealed that heparanase inhibited T cell function and activation through modulation of their cytokine repertoire, indicated by a marked increase in the levels of Interleukin-4, Interleukin-6 and Interleukin-10, and a parallel decrease in Interleukin-12, tumor necrosis factor-alfa and interferon-gamma. Using point mutated inactive enzyme, we found that the shift in cytokine profile was independent of heparanase enzymatic activity.

Conclusions

Our results indicate a significant role of heparanase in bone marrow transplantation biology, facilitating engraftment and suppressing graft-versus-host disease, apparently through an effect on T cell activation and cytokine production pattern.

Klotho suppresses TNF-alpha-induced expression of adhesion molecules in the endothelium and attenuates NF-kappaB activation

Klotho is a senescence suppressor protein that, when overexpressed, extends the lifespan of mice. Klotho-disrupted mice exhibit atherosclerosis and endothelial dysfunction, which led us to investigate the effect of the Klotho protein on vascular inflammation, particularly adhesion molecule expression. In this study, human umbilical vein endothelial cells (HUVECs) were preincubated with Klotho protein and then exposed to tumor necrosis factor-alpha (TNF-alpha) or vehicle. Reverse transcription-PCR and Western blot analyses revealed that Klotho suppressed TNF-alpha-induced expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). NF-kappaB activation, IkappaB phosphorylation induced by TNF-alpha were also attenuated by Klotho protein administration. The inhibition of eNOS phosphorylation by TNF-alpha was reversed by Klotho. Furthermore, Klotho inhibited TNF-alpha-induced monocyte adhesion to HUVECs and suppressed adhesion molecule expression in an organ culture of the rat aorta. These results suggest that Klotho suppresses TNF-alpha-induced expression of adhesion molecules and NF-kappaB activation. Klotho may have a role in the modulation of endothelial inflammation.

Administration of heparanase-III improves the survival and angiogenesis of rat skin autografts

AIM

Heparanase, a glycohydrolase enzyme, cleaves heparan sulfate in the tissue matrix. Heparan sulfate degradation causes the release of angiogenic and growth factors, leading to angiogenesis. The aim of this paper was to evaluate the angiogenic effect of heparinase-III administration on skin autograft healing in rat.

METHODS

Four groups of 14 adult male Charles River rats were enrolled. Full thickness skin autografts (15 mm in diameter) were made on the interscapular region of each rat. After 24 hours, 0.1 cc of heparanase, at the three concentrations of 0.1, 0.2, and 0.4 units, were injected intradermally into the grafts of each of the three case groups. The control group received an equal volume of the vehicle (buffered phosphate solution). After 5 days, biopsy specimens from skin grafts of 5 randomly selected rats of each group were submitted for histological studies.

RESULTS

The concentration of vessels (with 5-50 mm in diameter) in the grafts of the groups receiving 0.2 and 0.4 units of heparanase-III was significantly more than that of the control group (100.43+/-11.24 and 95.85+/-12.44 vs 71.42+/-5.22 vessels/mm(2), P<0.05). The graft survival time of the group that received 0.2 U heparanase-III was significantly longer than that of the control group (15.43+/-0.72 vs 13.23+/-0.69 days; P<0.05).

CONCLUSIONS

Heparanase-III administration improves the healing of rat skin autografts through induction of angiogenesis.

Heparanase prevents the development of type 1 diabetes in non-obese diabetic mice by regulating T-cell activation and cytokines production

BACKGROUND

Heparanase is an endo-beta-D-glucuronidase that cleaves heparan sulfate saccharide chains. The enzyme promotes cell adhesion, migration and invasion, and was shown to play a significant role in cancer metastasis and angiogenesis.

METHODS

The present study focuses on the involvement of heparanase in autoimmunity, applying the murine non-obese diabetic (NOD) model, a T-cell-dependent disease often used to investigate the pathophysiology of type 1 diabetes.

RESULTS

It was found that intra-peritoneal administration of heparanase ameliorated the clinical signs of the disease. In vitro studies revealed that heparanase has an inhibitory effect on the activation of T-cells through modulation of their repertoire of cytokines indicated by a marked increase in the levels of IL-4 and IL-10, and a parallel decrease in IL-12, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma).

CONCLUSIONS

We suggest that heparanase induces a shift from a Th1- to Th2-phenotype, resulting in inhibition of diabetes in NOD mice and possibly other autoimmune disorders.

Endocrine regulation of ageing

Over the past 15 years it has become clear that mutations in genes that regulate endocrine signalling pathways can prolong lifespan. Lifespan can be increased by altered endocrine signalling in a group of cells or a single tissue, which indicates that crosstalk between tissues functions to coordinate ageing of the organism. These endocrine pathways might serve as targets for the manipulation of the ageing process and prevention of age-related diseases.

Heparanase induces Akt phosphorylation via a lipid raft receptor

The endoglycosidase heparanase is the predominant enzyme that degrades heparan sulfate side chains of heparan sulfate proteoglycans, activity that is strongly implicated in tumor metastasis. Apart of its well characterized enzymatic activity, heparanase was noted to exert also enzymatic-independent functions. Among these is the induction of Akt/PKB phosphorylation noted in endothelial- and tumor-derived cells. Protein domains of heparanase required for signaling were not identified to date, nor were identified heparanase binding proteins/receptors capable of transmitting heparanase signals. Here, we examined the possible function of mannose 6-phosphate receptor (MPR) and low-density lipoprotein-receptor related protein (LRP), recently implicated in cellular uptake of heparanase, as heparanase receptors mediating Akt phosphorylation. We found that heparanase addition to MPR- and LRP-deficient fibroblasts elicited Akt activation indistinguishable from control fibroblasts. In contrast, disruption of lipid rafts abrogated Akt/PKB phosphorylation following heparanase addition. These results suggest that lipid raft-resident receptor mediates heparanase signaling.

Heparan sulfates mediate pressure-induced increase in lung endothelial hydraulic conductivity via nitric oxide/reactive oxygen species

We investigated the nonlinear dynamics of the pressure vs. hydraulic conductivity (Lp) relationship in lung microvascular endothelial cells and demonstrate that heparan sulfates, an important component of the endothelial glycocalyx, participate in pressure-sensitive mechanotransduction that results in barrier dysfunction. The pressure vs. Lp relationship was complex, possessing both time- and pressure-dependent components. Pretreatment of lung capillary endothelial cells with heparanase III completely abolished the pressure-induced increase in Lp. This extends our ( 7 ) previous observation regarding heparan sulfates as mechanotransducers for shear stress. Inhibition of nitric oxide (NO) synthase with l-NAME ( NG-nitro-l-arginine methyl ester HCl) and intracellular scavenging of reactive oxygen species (ROS) by TBAP [tetrakis-(4-benzoic acid) porphorin] significantly attenuated the pressure-induced Lp response. Intracellular NO/ROS were visualized using the fluorescent dye, 2′7′-dichlorofluorescein diacetate (DCFA), and cells demonstrated a pressure-induced increase in intracellular fluorescence. Heparanase pretreatment significantly reduced the pressure-induced increase in intracellular fluorescence, suggesting that cell-surface heparan sulfates directly participate in mechanotransduction that results in NO/ROS production and increased permeability. This is the first report to demonstrate a role for heparan sulfates in pressure-mediated mechanotransduction and barrier regulation. These observations may have important clinical implications during conditions where pulmonary microvascular pressure is elevated.

Anti-oxidative effect of Klotho on endothelial cells through cAMP activation

Klotho, a regulatory factor implicated in countering the aging process, has been reported to ameliorate endothelial dysfunction in vivo. To clarify whether Klotho protein directly affects endothelial cell function, we studied the effects of membrane-form Klotho on manganese superoxide dismutase (Mn-SOD) expression and nitric oxide production in human umbilical vein endothelial cells (HUVEC). We incubated HUVEC with conditioned medium from COS-1 cells transfected with expression vector, pCAGGS-klotho (Klotho-CM) or a recombinant, purified 6His-tagged Klotho protein. Both Klotho-CM and 6His-tagged Klotho protein enhanced Mn-SOD expression by approximately two-fold, partially via activation of the cAMP signaling pathway. Furthermore, Klotho-CM increased nitric oxide production, which also contributed to the up-regulation of Mn-SOD. Using the oxidation-sensitive dye dihydroethidium, we found that Klotho inhibited angiotensin II-induced reactive oxygen species production in HUVEC. These findings provide new insights into the mechanisms of Klotho action and support the therapeutic potential of membrane-form Klotho to regulate endothelial function.

Metabolism of pyrene by aquatic crustacean, Daphnia magna

The aquatic crustacean Daphnia magna is an important species for ecotoxicological study, and is often used as a test organism for environmental risk assessment. However, the mechanism of xenobiotic metabolism by this species has not been studied in detail. In the present study, pyrene was used as model substance to investigate the mechanism of xenobiotic metabolism in D. magna. The results of 24-h exposure experiments showed that D. magna could metabolize pyrene and biotransform it into water-soluble metabolites. On the other hand, the metabolism of pyrene was significantly inhibited by SKF-525A as the cytochrome P450 (CYP) inhibitor. These observations indicated that oxidation by CYP participated in the biotransformation of pyrene by D. magna. We also identified the pyrene metabolites formed by D. magna by HPLC with an electrospray ionization triple quadrupole mass spectrometry detector (LC/ESIMS/MS) and de-conjugation by sulfatase, beta-glucuronidase, and beta-glucosidase. One of the metabolites was ionized in ESI negative mode and formed a dominant mass of m/z 297 (MS) with the product ion of m/z 217 (MS2). Furthermore, this metabolite formed 1-hydroxypyrene on treatment with sulfatase. This metabolite was considered to be a sulfate conjugate of oxidized pyrene (1-hydroxypyrenesulfate). Furthermore, we quantified the deconjugated 1-hydroxypyrene formed by the above enzyme treatment. It showed that 52% of the total metabolized pyrene was biotransformed into 1-hydroxypyrene-sulfate, and more than 73% was biotransformed into oxidized pyrene conjugate. These results indicated that CYP and several conjugation enzymes participate in its biotransformation, and sulfation is important in D. magna for metabolism and elimination of xenobiotics.

Heparanase deglycanation of syndecan-1 is required for binding of the epithelial-restricted prosecretory mitogen lacritin

Cell surface heparan sulfate (HS) proteoglycans are carbohydrate-rich regulators of cell migratory, mitogenic, secretory, and inflammatory activity that bind and present soluble heparin-binding growth factors (e.g., fibroblast growth factor, Wnt, Hh, transforming growth factor β, amphiregulin, and hepatocyte growth factor) to their respective signaling receptors. We demonstrate that the deglycanated core protein of syndecan-1 (SDC1) and not HS chains nor SDC2 or -4, appears to target the epithelial selective prosecretory mitogen lacritin. An important and novel step in this mechanism is that binding necessitates prior partial or complete removal of HS chains by endogenous heparanase. This limits lacritin activity to sites where heparanase appears to predominate, such as sites of exocrine cell migration, secretion, renewal, and inflammation. Binding is mutually specified by lacritin's C-terminal mitogenic domain and SDC1's N terminus. Heparanase modification of the latter transforms a widely expressed HS proteoglycan into a highly selective surface-binding protein. This novel example of cell specification through extracellular modification of an HS proteoglycan has broad implications in development, homeostasis, and disease.

Combination cancer therapy by hapten-targeted prodrug-activating enzymes and cytokines

Combination therapy can help overcome limitations in the treatment of heterogeneous tumors. In the current study, we examined whether multiple therapeutic agents could be targeted to anti-dansyl single-chain antibodies (DNS scFv) that were anchored on the plasma membrane of cancer cells. Functional DNS scFv could be stably expressed on CT-26 colon cancer cells both in vitro and in vivo. Dansyl moieties were covalently attached to recombinant beta-glucuronidase (betaG) and interleukin 2 (IL-2) via a flexible poly(ethylene glycol) linker to form DNS-PEG-betaG and DNS-PEG-IL-2 conjugates. The conjugates displayed enzymatic and splenocyte-stimulatory activities, respectively, that were similar to those of the unmodified proteins. The conjugates selectively bound CT-26 cells that expressed anti-DNS scFv (CT-26/DNS cells) but not CT-26 cells that expressed control scFv (CT-26/phOx cells). DNS-PEG-betaG preferentially activated a glucuronide prodrug (BHAMG) of p-hydroxy aniline mustard at CT-26/DNS cells in culture and accumulated in subcutaneous CT-26/DNS tumors after intravenous administration. Systemic administration of DNS-PEG-IL-2 or DNS-PEG-betaG and BHAMG significantly delayed the growth of CT-26/DNS but not control CT-26/phOx tumors. Combination treatment with DNS-PEG-betaG and BHAMG followed by DNS-PEG-IL-2 therapy significantly suppressed the growth of CT-26/DNS tumors as compared to either single-agent regimen. These results show that at least two DNS-modified therapeutic agents can be selectively delivered to DNS scFv receptors in vitro and in vivo, allowing combination therapy of DNS scFv-modified tumors.

Heparanase mechanisms of melanoma metastasis to the brain: Development and use of a brain slice model

Heparanase (HPSE-1) is an endo-beta-D-glucuronidase that cleaves heparan sulfate (HS) chains of proteoglycans (HSPG), and its expression has been associated with increased cell growth, invasion, and angiogenesis of tumors as well as with embryogenesis and tissue development. Since metastatic cancer cells express HPSE-1, we have developed an orthotopic brain slice model to study HPSE-1 involvement in brain-metastatic melanoma. This model allows for the characterization of tumor cell invasion at both quantitative and qualitative levels. Brain-metastatic melanoma cells (B16B15b) showed augmenting levels of HPSE-1 protein expression in a time-dependent manner. Secondly, B16B15b cells pre-treated with HPSE-1 showed a significant increase in the number of cells that invaded into the brain tissue. Finally, HPSE-1 exposure-augmented invasion depth in brain sections by brain-metastatic melanoma cells. We concluded that applying this brain slice model can be beneficial to investigate HPSE-1- related in vivo modalities in brain-metastatic melanoma and brain invasion in general. These results also further emphasize the potential relevance of using this model to design therapies for controlling this type of cancer by blocking HPSE-1 functionality.

Difference in Plasma Metabolite Concentration after Ingestion of Lemon Flavonoids and Their Aglycones in Humans

The concentrations of metabolites in human plasma after ingestion of flavanone glycosides (FG) and their aglycones (FA) in lemon were examined. FG consisting abundantly of eriocitrin were prepared from lemon peel and FA consisting abundantly of eriodictyol were prepared from FG by treatment with beta-glucosidase. Eriodictyol, homoeriodictyol, and hesperetin in plasma up to 4 h after ingestion of FG with water or FA with water by subjects were not detected in plasma of non-enzyme treatment but in plasma after treatment with beta-glucronidase and sulfatase. Metabolites in plasma after ingestion of FG and FA in humans were shown to exist as the glucuro- and/or sulfo-conjugates of eriodictyol, homoeriodictyol, and hesperetin. After ingestion of FA, the concentration of metabolites in plasma exhibited a high maximum peak at 1 h. The AUC (area under the blood concentration time curve) level of metabolites of FA was higher than that of FG. FA were suggested to be absorbed faster and in higher amounts than FG. The AUC of metabolites in subject plasma after ingestion of FG with flavonoid-depleted lemon juice was shown to change to a low level in comparison with that of FG with water. The maximum concentration peak of metabolites in plasma was faster at 0.5 h than FA with water but the AUC level was similar to FA with water, when subjects ingested FA with vodka (40%, ethanol). The absorption hour of FG and FA was shown to be affected by the co-existing solution.

Endothelial cell injury by high glucose and heparanase is prevented by insulin, heparin and basic fibroblast growth factor

BACKGROUND

Uncontrolled hyperglycemia is the main risk factor in the development of diabetic vascular complications. The endothelial cells are the first cells targeted by hyperglycemia. The mechanism of endothelial injury by high glucose is still poorly understood. Heparanase production, induced by hyperglycemia, and subsequent degradation of heparan sulfate may contribute to endothelial injury. Little is known about endothelial injury by heparanase and possible means of preventing this injury.

OBJECTIVES

To determine if high glucose as well as heparanase cause endothelial cell injury and if insulin, heparin and bFGF protect cells from this injury.

METHODS

Cultured porcine aortic endothelial cells were treated with high glucose (30 mM) and/or insulin (1 U/ml) and/or heparin (0.5 microg/ml) and /or basic fibroblast growth factor (bFGF) (1 ng/ml) for seven days. Cells were also treated with heparinase I (0.3 U/ml, the in vitro surrogate heparanase), plus insulin, heparin and bFGF for two days in serum free medium. Endothelial cell injury was evaluated by determining the number of live cells per culture and lactate dehydrogenase (LDH) release into medium expressed as percentage of control.

RESULTS

A significant decrease in live cell number and increase in LDH release was found in endothelial cells treated with high glucose or heparinase I. Insulin and/or heparin and/or bFGF prevented these changes and thus protected cells from injury by high glucose or heparinase I. The protective ability of heparin and bFGF alone or in combination was more evident in cells damaged with heparinase I than high glucose.

CONCLUSION

Endothelial cells injured by high glucose or heparinase I are protected by a combination of insulin, heparin and bFGF, although protection by heparin and/or bFGF was variable.

Heparanase improves mouse embryo implantation

OBJECTIVE

To improve mouse embryonic implantation by recombinant heparanase supplementation. Heparanase, an endoglycosidase-degrading heparan sulfate proteoglycan, may have a role in embryonic implantation because of its enzymatic, angiogenic, and adhesive properties. Increasing endometrial receptivity could improve one of the most difficult pathologies in human fertility.

DESIGN

Comparison between mouse blastocysts obtained after 24-hour incubation of morulae with or without heparanase.

SETTING

Experimental laboratory in a medical center.

ANIMAL(S)

Mice.

INTERVENTION(S)

Morulae were flushed from CB6F1 female mice and incubated for 24 hours at 37 degrees C in M16 medium supplemented with 0.1 mg/mL heparanase (n = 203), with albumin (n = 60), or with medium alone (n = 258).

MAIN OUTCOME MEASURE(S)

Blastocysts were evaluated by heparanase immunostaining (n = 10), activity assay (n = 283), and transfer to foster mice uterine horns (n = 228). The number of implantation sites was compared.

RESULT(S)

Immunostaining demonstrated that heparanase is constitutively expressed in mouse morulae and blastocyts. Heparanase supplementation resulted in increased staining and enzymatic activity in blastocyts. Implantation rates for the heparanase, M16 medium, and albumin groups, were 36.9%, 17.8%, and 20%, respectively (P<.01).

CONCLUSION(S)

Heparanase was found to be constitutively expressed by blastocyst-stage embryos. Moreover, the amount of heparanase was markedly increased by incubation of morulae with recombinant heparanase, evaluated by immunostaining and enzymatic activity. Heparanase supplementation resulted in approximately a twofold increase in embryo implantation rate in vivo. Taken together, these data suggest that heparanase is actively involved in embryo implantation.

Axonal transport of the cellular prion protein is increased during axon regeneration

The cellular prion protein, PrPc, is a glycosylphosphatidylinositol-anchored cell surface glycoprotein and a protease-resistant conformer of the protein may be the infectious agent in transmissible spongiform encephalopathies. PrPc is localized on growing axons in vitro and along fibre bundles that contain elongating axons in developing and adult brain. To determine whether the growth state of axons influenced the expression and axonal transport of PrPc, we examined changes in the protein following post-traumatic regeneration in the hamster sciatic nerve. Our results show (1) that PrPc in nerve is significantly increased during nerve regeneration; (2) that this increase involves an increase in axonally transported PrPc; and (3) that the PrPc preferentially targeted for the newly formed portions of the regenerating axons consists of higher molecular weight glycoforms. These results raise the possibility that PrPc may play a role in the growth of axons in vivo, perhaps as an adhesion molecule interacting with the extracellular environment through specialized glycosylation.

Heparanase as a molecular target of cancer chemotherapy

Cancer cells require the ability to degrade the extracellular matrix (ECM) in order to turn into invasive and metastatic cancer cells. Many proteases and glycosidases are essential in the process of dissolving the components of the ECM. An endo-beta-D-glucuronidase, heparanase, is capable of specifically degrading one of the ECM components, heparan sulfate, and this activity is associated with the metastatic potential of tumor cells. Since heparanase mRNA is overexpressed in many human tumors (e.g., hepatomas, head and neck tumors, and esophageal carcinomas), the mechanisms regulating the activity of heparanase should be clarified; considering the possible role of heparanase in cancer, the development of heparanase inhibitors would appear to be advantageous. This review will focus on recent findings that have contributed to the characterization of heparanase and to the elucidation of the transcriptional regulation of heparanase mRNA expression, as well as the development of heparanase inhibitors.

Role of heparan sulfate in dextral heart looping in chick

Heparan sulfate (HS) has been shown to be involved in left-right asymmetry formation, including the process of dextral heart looping during embryonic development. The structural features of HS required in this process, however, have not been explored. In this study, we examined the structure of HS from the heart-forming regions (or heart fields) of Hamburger and Hamilton stage 5-9 chick embryos. No significant differences were found in HS to chondroitin sulfate (CS) ratio, HS chain length, or [35S] sulfate incorporation at HS disaccharide level between the left and the right heart fields. Compared to other parts of the embryo, however, lower ratio of HS to CS, shorter HS chain length, and higher [35S] sulfate incorporation at 6-O position of the glucosamine residue in the HS chains were observed in the heart-forming regions. Moreover, HS from the left and the right heart fields exhibit differential cleavage by heparanase, an endo-beta-d- glucuronidase that cleaves specific sequences within the HS chain. In embryo culture, microinjection of the active human heparanase enzyme into the right but not the left pericardial cavity at stage 7-8+ resulted in reversed heart looping in a dose-dependent manner. Heart reversal following microinjection of heparin or heparin derivatives suggests the involvement of N- and 6-O-sulfation but not 2-O-sulfation in the heart looping process.

Internalization of bioluminescent Escherichia coli and Salmonella Montevideo in growing bean sprouts

AIMS

Investigate the interaction of bioluminescent Escherichia coli and Salmonella Montevideo with germinating mung bean sprouts.

METHODS AND RESULTS

E. coli or Salm. Montevideo introduced on mung beans became established both internally and externally on sprouts after the initial 24 h germinating period. In both cases the inoculated bacterium formed the predominant microflora on the sprouted beans throughout. From the bioluminescent profile of inoculated sprouting beans, bacterial growth was found to be in close proximity to the roots but not on the hypocotyls. Clumps (biofilms) of cells with low viability were observed within the grooves between epidermal cells on hypocotyls. Treatment with 20,000 ppm sodium hypochlorite removed the majority of bacteria from the surface of hypocotyls although nonviable single cells were occasionally observed. However, viable bacteria were recovered from the apoplastic fluid, and extracts of surface-sterilized sprouts indicating that the internal bacterial populations had been protected. This was confirmed using in situ beta-glucuronidase staining of surface-sterilized sprouts where cleaved enzyme substrate (by the action of internalized E. coli) was visualized within the plant vascular system.

CONCLUSIONS

E. coli or Salmonella present on seeds become internalized within the subsequent sprouts and cannot be removed by postharvest biocidal washing.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mung bean production should be carefully controlled to prevent contamination occurring in order to minimize the health risk associated with raw bean sprouts.

Inverse correlation between heparan sulfate composition and heparanase-1 gene expression in thyroid papillary carcinomas: a potential role in tumor metastasis

PURPOSE

Heparanase-1 (HPR1) is an endoglycosidase that degrades the side chains of heparan sulfate proteoglycan (HSPG), a key component in cell surfaces, the extracellular matrix (ECM), and the basement membrane (BM). The purpose of this study was to evaluate HPR1 expression in thyroid neoplasms and its effect in degrading the HSPG substrates in the ECM and BM and to determine its role in thyroid tumor metastasis.

EXPERIMENTAL DESIGN

HPR1 mRNA expression was analyzed by using in situ hybridization with a digoxigenin-labeled antisense RNA probe on paraffin-embedded tumor sections and reverse transcription-PCR (RT-PCR) in fresh tumor tissues. HPR1 protein expression was analyzed by using immunohistochemical staining with an anti-HPR1 rabbit antiserum and immunofluorescence (IF) with an anti-HPR1 monoclonal antibody. The effect of HPR1 expression in thyroid neoplasms was analyzed by examining the presence and integrity of the HSPG substrates in the ECM and BM using IF staining with a specific monoclonal antibody against heparan sulfate. The relationship of HPR1 expression in papillary thyroid carcinomas (PTCs) with various clinicopathological parameters was analyzed statistically. The role of HPR1 in thyroid tumor metastasis was further examined by comparing HPR1 levels in 10 thyroid tumor cell lines to their invasive and metastatic potential.

RESULTS

In situ hybridization analysis of 81 tumor samples (62 papillary carcinomas and 19 follicular adenomas) revealed that HPR1 was expressed at a much higher frequency in PTCs than in follicular adenomas (P<0.05). RT-PCR analyses of fresh tumor tissues revealed that HPR1 mRNA could be detected in primary and metastatic thyroid papillary carcinomas. HPR1 expression was confirmed at the protein level by immunohistochemical staining and IF stainings. IF analysis of HSPG revealed that HS was deposited abundantly in the BM of normal thyroid follicles and benign follicular adenomas but was absent in most thyroid papillary carcinomas. A lack of heparan sulfate in PTCs inversely correlated with HPR1 expression. Clinicopathological data analyses revealed that PTCs with local and distant metastases scored HPR1 positive at a significantly higher frequency than nonmetastatic thyroid cancers (P=0.02). To further explore the role of HPR1 in tumor metastases, we characterized HPR1 expression in 10 thyroid tumor cell lines using RT-PCR and Western blot and measured HPR1 enzymatic activity using a novel ELISA. HPR1 was differentially expressed in different types of cell lines; overexpression of HPR1 in two tumor cell lines led to a dramatic increase of their invasive potential in vitro in an artificial BM.

CONCLUSIONS

Our study suggests that HPR1 expressed in papillary carcinomas is functional and that HPR1 expression is associated with thyroid tumor malignancy and may significantly contribute to thyroid tumor metastases.

Probiotic effects of beta-glucuronidase on the peach-potato aphid Myzus persicae (Aphididae)

beta-glucuronidase (GUS) is a reporter protein commonly expressed in transgenic plants allowing the visualization of the transformed individuals. In our recent work, we showed that consumption of transformed potato plants expressing this GUS enzyme improves performance of the phloem feeding aphid Myzus persicae. Those results led us to the conclusion that the expression of GUS in potato plants might be responsible for the probiotic effect measured in feeding aphids. In the present paper, artificial diets were used to provide active GUS (10 and 500 microg ml(-1)), inactivated heated GUS (500 microg ml(-1)), glucuronic acid (10, 100 and 500 microg ml(-1)), and bovine serum albumin (500 microg ml(-1)) to M. persicae. Our results reveal that these chemicals provided as food intake might influence the biological parameters of this aphid. Experiments showed a probiotic effect of 500 microg ml(-1) GUS diet, resulting in reduced larval mortality, and increased adult reproduction period and fecundity, which led to an increased population growth potential (r(m)=0.17+/-0.01 versus r(m)=0.12+/-0.03 for aphids fed on control diet). A lower amount of added GUS led to fewer variations, biological parameters being only slightly altered (r(m)=0.14+/-0.03). Statistically similar alterations of the biological parameters were obtained when comparing aphids fed on the diet added with inactivated GUS or the non-structural bovine serum albumin protein (r(m)=0.15+/-0.02 and 0.14+/-0.03, respectively). Feeding assays conducted with glucuronic acid supplemented diets enhanced longevity and nymph production of the adult aphids and reduced larval mortality, resulting in r(m)=0.15+/-0.02 for the highest dose (500 microg ml(-1)). Although 100 microg ml(-1) glucuronate diet did not induce any effect on M. persicae (r(m)=0.12+/-0.03), aphids fed on 10 microg ml(-1) glucuronate diet exhibited unexpected reduced demographic parameters (r(m)=0.10+/-0.03). Immuno-histological analysis showed GUS labeling along the whole digestive epithelium of adults and in various tissues including embryos and bacteriocytes. These results suggest that GUS crosses through the digestive tract. Western blots performed with protein extracts of transformed potato plants expressing the gus gene showed a unique band of molecular weight 76 kDa. On the contrary, in extracts from aphids fed on transgenic potato plants or bred on GUS 500 microg ml(-1) artificial diet, several proteins of lower molecular weight were hybridized, revealing proteolysis of ingested GUS. It is concluded that GUS protein, and more precisely GUS activity, is responsible for the probiotic effects on aphid feeding. The possible pathways of induction of such physiological alterations by GUS are discussed.

Apolipoprotein E binding to low density lipoprotein receptor-related protein-1 inhibits cell migration via activation of cAMP-dependent protein kinase A

Smooth muscle cell migration and proliferation contribute to neointimal hyperplasia and vascular stenosis after endothelial denudation. Previous studies revealed that apolipoprotein E (apoE) is an effective inhibitor of platelet-derived growth factor-directed smooth muscle cell migration and proliferation and that the anti-migratory function is mediated via apoE binding to low density lipoprotein receptor-related protein-1 (LRP-1). This study was undertaken to identify the intracellular pathway by which apoE binding to LRP-1 results in inhibition of smooth muscle cell migration. The results showed that apoE increased intracellular cAMP levels 3-fold after 5 min, and the increase was sustained for more than 1 h. As a consequence, apoE also increased protein kinase A (PKA) activity in smooth muscle cells. Importantly, suppression of PKA activity with a cell-permeable peptide inhibitor of PKA abolished the inhibitory effect of apoE on smooth muscle cell migration. These results indicated that apoE inhibition of smooth muscle cell migration is mediated via the activation of cAMP-dependent PKA. Additional experiments revealed that apoE also inhibited fibroblasts migration toward platelet-derived growth factor by a similar mechanism of cAMP-dependent PKA activation. It is noteworthy that apoE failed to increase cAMP levels or inhibit migration of LRP-1-negative mouse embryonic fibroblasts and LRP-1-deficient smooth muscle cells. Taken together, these findings established the mechanism by which apoE inhibits cell migration, i.e. via cAMP-dependent protein kinase A activation as a consequence of its binding to LRP-1.

Chemistry and biological significance of essential oils of Cymbopogon citratus from Pakistan

Steam distilled oil of Cymbopogon citratus was analyzed by Gas Chromatographic-Mass Spectrometry (GC-MS) and citral was found as major constituent. The oil exhibited significant inhibition of beta-glucuronidase activity and also showed activities against some tested human, plant and animal pathogens. The minimum inhibitory concentrations could not be determined due to the lack of some chemicals.