PREVENTION OF CYCLOPHOSPHAMIDE-INDUCED HEMORRHAGIC CYSTITIS BY GLUCOSE-MANNOSE BINDING PLANT LECTINS

Spasmolytic and Uroprotective Effects of Apigenin by Downregulation of TGF-β and iNOS Pathways and Upregulation of Antioxidant Mechanisms: In Vitro and In Silico Analysis

Apigenin is a phytochemical obtained from Chamomilla recutita. Its role in interstitial cystitis is not yet known. The present study is aimed at understanding the uroprotective and spasmolytic effects of apigenin in cyclophosphamide-induced interstitial cystitis. The uroprotective role of apigenin was analyzed by qRT-PCR, macroscopic analysis, Evans blue dye leakage, histological evaluation, and molecular docking. The spasmolytic response was measured by adding cumulative concentrations of apigenin to isolated bladder tissue pre-contracted with KCl (80 mM) and carbachol (10^-9-10^-4) on non-incubated and pre-incubated tissues with atropine, 4DAMP, methoctramine, glibenclamide, barium chloride, nifedipine, indomethacin, and propranolol. Apigenin inhibited pro-inflammatory cytokines (IL-6, TNF-α and TGF 1-β) and oxidant enzymes (iNOS) while increasing antioxidant enzymes (SOD, CAT, and GSH) in CYP-treated groups compared to the control. Apigenin restored normal tissue of the bladder by decreasing pain, edema, and hemorrhage. Molecular docking further confirmed the antioxidant and anti-inflammatory properties of apigenin. Apigenin produced relaxation against carbachol-mediated contractions, probably via blockade of M₃ receptors, K_ATP channels, L-type calcium channels, and prostaglandin inhibition. While the blockade of M₂ receptors, K_IR channels, and β-adrenergic receptors did not contribute to an apigenin-induced spasmolytic effect, apigenin presented as a possible spasmolytic and uroprotective agent with anti-inflammatory, antioxidant effects by attenuating TGF-β/iNOS-related tissue damage and bladder muscle overactivity. Thus, it is a potential agent likely to be used in treatment of interstitial cystitis.

The anti-inflamatory effect of Andira anthelmia lectin in rats involves inhibition of the prostanoid pathway, TNF-α and lectin domain

OBJECTIVE

To investigate the effect and mechanisms of Andira anthelmia lectin in rat models of acute inflammation.

MATERIAL

AAL anti-inflammatory activity was evaluated in Wistar rat models of paw edema and peritonitis.

METHODS

AAL (0.01-1 mg/kg i.v.) was injected 30 min before stimulation with carrageenan and with initial and late phase inflammatory mediators into the animals paw or peritoneum for evaluation of cell migration (optical and intravital microscopy), paw edema (plethysmometry and histopathology); hyperalgesia (analgesimetry).

RESULTS

AAL inhibited leukocyte migration induced by carrageenan, mainly neutrophils to the peritoneal fluid, decreasing leukocyte adhesion. In the peritoneal fluid, AAL reduced the gene expression of TNF-α and cyclooxygenase, as well the levels of PGE₂. AAL inhibited the paw edema induced by carrageenan, serotonin, histamine, TNF-α, PLA₂ and PGE₂, but not by L-arginine. In this model, AAL also inhibited mechanical hypernociception induced by TNF-α, PGE₂, db-cAMP and capsaicin, and the activity of myeloperoxidase in the paw tissues.

CONCLUSION

AAL presents anti-inflammatory effect in acute models of rat inflammation involving the participation of prostaglandins, TNF-α and lectin domain.

Antinociceptive and Anti-Inflammatory Effects of Saline Extract and Lectin-Rich Fraction from Microgramma vacciniifolia Rhizome in Mice

Previous studies have characterized a saline extract from Microgramma vacciniifolia rhizome and its lectin (MvRL)-rich fraction with low acute toxicity. In the present study, we evaluated these preparations for acute toxicity (1,000 mg/kg) and antinociceptive and anti-inflammatory activities (100-400 mg/kg for the extract and 25-50 mg/kg for the fraction). No signs of toxicity were observed. Both the extract and fraction increased the latency period for nociception in the hot plate assay, decreased writhing induced by acetic acid, and promoted analgesic effects in phases 1 and 2 of the formalin test. The antinociceptive mechanism was attributed to interactions with opioid receptors and K⁺ ATPase channels. The extract and fraction decreased carrageenan-induced paw edema in 46.15 % and 77.22 %, respectively, at the highest doses evaluated. Furthermore, the fraction was shown to act on the bradykinin pathway. The ability to decrease leukocyte migration after treatment was also verified in the peritonitis and air pouch models. In exudates collected from air pouches, decreased tumor necrosis factor (TNF)-α and increased interleukin (IL)-10 levels were noted. Both the extract and fraction also effectively inhibited the development of granulomatous tissue. In conclusion, the substances investigated in this study can be used for the development of novel therapeutic options for pain and inflammatory processes.

ConA-Like Lectins: High Similarity Proteins as Models to Study Structure/Biological Activities Relationships

Lectins are a widely studied group of proteins capable of specific and reversible binding to carbohydrates. Undoubtedly, the best characterized are those extracted from plants of the Leguminosae family. Inside this group of proteins, those from the Diocleinae subtribe have attracted attention, in particular Concanavalin A (ConA), the best-studied lectin of the group. Diocleinae lectins, also called ConA-like lectins, present a high similarity of sequence and three-dimensional structure and are known to present inflammatory, vasoactive, antibiotic, immunomodulatory and antitumor activities, among others. This high similarity of lectins inside the ConA-like group makes it possible to use them to study structure/biological activity relationships by the variability of both carbohydrate specificity and biological activities results. It is in this context the following review aims to summarize the most recent data on the biochemical and structural properties, as well as biological activities, of ConA-like lectins and the use of these lectins as models to study structure/biological activity relationships.

Anti-inflammatory effects of phytochemicals from fruits, vegetables, and food legumes: A review

Inflammation is the first biological response of the immune system to infection, injury or irritation. Evidence suggests that the anti-inflammatory effect is mediated through the regulation of various inflammatory cytokines, such as nitric oxide, interleukins, tumor necrosis factor alpha-α, interferon gamma-γ as well as noncytokine mediator, prostaglandin E₂. Fruits, vegetables, and food legumes contain high levels of phytochemicals that show anti-inflammatory effect, but their mechanisms of actions have not been completely identified. The aim of this paper was to summarize the recent investigations and findings regarding in vitro and animal model studies on the anti-inflammatory effects of fruits, vegetables, and food legumes. Specific cytokines released for specific type of physiological event might shed some light on the specific use of each source of phytochemicals that can benefit to counter the inflammatory response. As natural modulators of proinflammatory gene expressions, phytochemical from fruits, vegetables, and food legumes could be incorporated into novel bioactive anti-inflammatory formulations of various nutraceuticals and pharmaceuticals. Finally, these phytochemicals are discussed as the natural promotion strategy for the improvement of human health status. The phenolics and triterpenoids in fruits and vegetables showed higher anti-inflammatory activity than other compounds. In food legumes, lectins and peptides had anti-inflammatory activity in most cases. However, there are lack of human study data on the anti-inflammatory activity of phytochemicals from fruits, vegetables, and food legumes.

Cyclophosphamide-induced Down-Regulation of Uroplakin II in the Mouse Urinary Bladder Epithelium is Prevented by S-Allyl Cysteine

The alkylating anticancer drug, cyclophosphamide (CP), induces a number of toxic effects including haemorrhagic cystitis (HC) in the urinary bladder. Uroplakins are unique urinary transmembrane proteins of urothelium, which may become potential targets of CP metabolites and reactive free radicals. Natural compounds, especially those rich in thiols, have shown protective effects against CP-induced HC. In this study, we studied the modulatory effect of the thiol-rich compound S-allyl cysteine (SAC) on the mRNA level of uroplakin II by real-time polymerase chain reaction and expression of uroplakin II protein by immunoblotting. SAC (150 mg/kg) showed significant (p < 0.001) protective effects against CP (200 mg/kg)-induced alteration in mRNA level and protein expression of uroplakin II. SAC also protected animals from CP-induced HC as assessed by gross morphological examination of urinary bladder. When compared with mercaptoethane sulphonic acid (mesna) (40 mg/kg), a known thiol-rich drug used in clinical application, SAC was found to be more efficacious in affording protection in urinary bladder tissues. Role of uroplakins in CP-induced urinary bladder toxicity has not been well investigated. This study demonstrated that uroplakins may be the potential target of toxic metabolites of CP and natural compounds such as SAC have the capacity to modulate their expression leading to reduced toxicity burden on the urinary bladder epithelium.

Purification and molecular characterization of a novel mannose-specific lectin from Dioclea reflexa hook seeds with inflammatory activity

A novel lectin present in Dioclea reflexa seeds (DrfL) was discovered and described in this study. DrfL was purified in a single step by affinity chromatography in a Sephadex G-50 column. The lectin strongly agglutinated rabbit erythrocytes and was inhibited by α-methyl-D-mannoside, D-mannose, and D-glucose. The hemagglutinating activity of DrfL is optimum at pH 5.0-7.0, stable up to 50 °C, and dependent on divalent cations. Similar to other lectins of the subtribe Diocleinae, the analysis by mass spectrometry indicated that DrfL has three chains (α, β, and γ) with masses of 25,562, 12,874, and 12,706 Da, respectively, with no disulfide bonds or glycosylation. DrfL showed inflammatory activity in the paw edema model and exhibited low cytotoxicity against Artemia sp.

The galactose-binding lectin isolated from Bauhinia bauhinioides Mart seeds inhibits neutrophil rolling and adhesion via primary cytokines

In this study, the amino acid sequence and anti-inflammatory effect of Bauhinia bauhinioides (BBL) lectin were evaluated. Tandem mass spectrometry revealed that BBL possesses 86 amino acid residues. BBL (1 mg/kg) intravenously injected in rats 30 min prior to inflammatory stimuli inhibited the cellular edema induced by carrageenan in only the second phase (21% - 3 h, 19% - 4 h) and did not alter the osmotic edema induced by dextran. BBL also inhibited carrageenan peritoneal neutrophil migration (51%), leukocyte rolling (58%) and adhesion (68%) and the neutrophil migration induced by TNF-α (64%). These effects were reversed by the association of BBL with galactose, demonstrating that the carbohydrate-binding domain is essential for lectin activity. In addition, BBL reduced myeloperoxidase activity (84%) and TNF-α (68%) and IL1-β (47%) levels. In conclusion, the present investigation demonstrated that BBL contains highly homologous isolectins, resulting in a total of 86 amino acid residues, and exhibits anti-inflammatory activity by inhibiting neutrophil migration by reducing TNF-α and IL1-β levels via the lectin domain.

Prevention of cyclophosphamide-induced hemorrhagic cystitis by resveratrol: a comparative experimental study with mesna

PURPOSE

Hemorrhagic cystitis (HC) is the most common urotoxic side effect of cyclophosphamide (CP). The aim of this study was to compare the classical efficacy of mesna (2-mercaptoethane sulfonate sodium) with three different doses of resveratrol (RES) on cyclophosphamide-induced HC in rats.

METHODS

Forty-six male Sprague-Dawley rats were divided into six groups. Group 1 served as a negative control (sham). Five groups received a single dose of cyclophosphamide (150 mg/kg) intraperitoneally at the same time. Groups 2, 3, 4, 5, and 6 received only CP, CP + 20 mg/kg RES, CP + 40 mg/kg RES, CP + 80 mg/kg RES, and CP + classical protocol of three doses of mesna (30 mg/kg three times), respectively. Antioxidants, cytokines, and malondialdehyde levels were measured in all groups. In addition, histopathological alterations in tissues were examined.

RESULTS

CP administration induced severe HC with marked edema, hemorrhage, and inflammation in group 2. RES 20 mg/kg showed meaningful protection against bladder damage compared to the control group. It was seen that RES 40 mg/kg gave weaker protection but RES 80 mg/kg was not found to be effective.

CONCLUSION

In conclusion, marked bladder protection was found in 20 and 40 mg/kg RES applications compared to the control group, but this protection was weaker than with mesna.

A C-type lectin receptor pathway is responsible for the pathogenesis of acute cyclophosphamide-induced cystitis in mice

Hemorrhagic cystitis often arises after cyclophosphamide (CYP) administration. As yet, however, the mechanism involved in its pathogenesis is unknown. In this study, it was found that the Fc receptor γ chain (FcRγ)- caspase recruitment domain-containing protein 9 (CARD9)-dependent pathway rather than the myeloid differentiation primary response gene 88 (MyD88)-dependent pathway is involved in the pathogenesis of acute CYP-induced cystitis in mice. Rapid and transient production of interleukin (IL)-6 and IL-1β was detected in the bladder at 4 hr, preceding IL-23 and IL-17A production and an influx of neutrophils, which reached a peak at 24 hr after injection. As assessed by weight, edema and neutrophil infiltration, cystitis was significantly attenuated in CARD9 knockout (KO) and FcRγKO mice, this attenuation being accompanied by impaired production of IL-1β, IL-6, IL-23 and IL-17A. The major source of IL-17A is the vesical γδ T cell population: IL-17AKO, CδKO and Tyk2KO mice showed little IL-17A production and reduced neutrophil infiltration in the bladder after CYP injection. These results suggest that FcRγ-CARD9-dependent production of proinflammatory cytokines such as IL-1β, IL-6, and IL-23 and the subsequent activation of IL-17A-producing γδ T cells are at least partly involved in the pathogenesis of acute CYP-induced cystitis in mice.

Effects of Canavalia lectins on acute inflammation in sensitized and non-sensitized rats

The anti-inflammatory activity of Canavalia seed lectins (Canavalia gladiata [CGL], Canavalia maritima [ConM] and Canavalia brasiliensis [ConBr]) was evaluated by intravenous administration in rats. In non-sensitized rats, cellular edema elicited by carrageenan was reduced (45-51 %) by ConM and (44-59 %) by CGL. Osmotic edema elicited by dextran was reduced by ConM and CGL in 27 % and 29 %. ConM and CGL reduced the edema elicited by L-arginine in 53 % and that of prostaglandin E2 in 48 % and 36 %. Leukocyte migration elicited by carrageenan was reduced in 49 % by ConM and in 55 % by CGL (attenuated in 4× by glucose) and peritoneal TNF-α content in 82 %. In rats sensitized, ConM inhibited the paw edema and leukocyte migration elicited by ovalbumin in 34 % and 70 %. ConM and CGL are anti-inflammatory, mainly in cellular events mediated by prostaglandin E₂, nitric oxide and TNF-α in non-sensitized rats. However, only ConM is anti-inflammatory in sensitized rats. CGL effect involves the lectin domain.

Intravesical liposome and antisense treatment for detrusor overactivity and interstitial cystitis/painful bladder syndrome

Purpose. The following review focuses on the recent advancements in intravesical drug delivery, which brings added benefit to the therapy of detrusor overactivity and interstitial cystitis/painful bladder syndrome (IC/PBS). Results. Intravesical route is a preferred route of administration for restricting the action of extremely potent drugs like DMSO for patients of interstitial cystitis/painful bladder syndrome (IC/PBS) and botulinum toxin for detrusor overactivity. Patients who are either refractory to oral treatment or need to mitigate the adverse effects encountered with conventional routes of administration also chose this route. Its usefulness in some cases can be limited by vehicle (carrier) toxicity or short duration of action. Efforts have been underway to overcome these limitations by developing liposome platform for intravesical delivery of biotechnological products including antisense oligonucleotides. Conclusions. Adoption of forward-thinking approaches can achieve advancements in drug delivery systems targeted to future improvement in pharmacotherapy of bladder diseases. Latest developments in the field of nanotechnology can bring this mode of therapy from second line of treatment for refractory cases to the forefront of disease management.

Role of CXCR2 and TRPV1 in functional, inflammatory and behavioural changes in the rat model of cyclophosphamide-induced haemorrhagic cystitis

BACKGROUND AND PURPOSE

Cyclophosphamide induces urotoxicity characterized by the development of cystitis, which involves bladder overactivity and inflammation. Here, we investigated the roles of chemokine receptor 2 (CXCR2) and transient receptor potential vanilloid 1 (TRPV1) channels in a rat model of cyclophosphamide-induced cystitis.

EXPERIMENTAL APPROACH

Cystitis induced by cyclophosphamide in rats was assessed by gross morphology, histology and immunohistochemistry of bladder tissue. mRNA for CXCR2 and TRPV1 channels were measured by RT-PCR. Nociceptive responses in paw and abdomen, along with cystometric measures were recorded.

KEY RESULTS

Cyclophosphamide, i.p., induced pain behaviour, bladder inflammation and voiding dysfunction. The CXCR2 antagonist, SB225002, the TRPV1 channel antagonist, SB366791 or their combination reduced the mechanical hypersensitivity of paw and abdominal area and nociceptive behaviour after cyclophosphamide. Cyclophosphamide-induced cystitis was characterized by haemorrhage, oedema, neutrophil infiltration and other inflammatory changes, which were markedly decreased by the antagonists. Up-regulation of CXCR2 and TRPV1 mRNA in the bladder after cyclophosphamide was inhibited by SB225002, SB366791 or their combination. Expression of CXCR2 and TRPV1 channels was increased in the urothelium after cyclophosphamide. Bladder dysfunction was shown by increased number of non-voiding contractions (NVCs) and bladder pressures and a reduction in bladder capacity (BC), voided volume (VV) and voiding efficiency (VE). SB225002 or its combination with SB366791 reduced bladder pressures, whereas SB225002, SB366791 or their combination increased BC, VV and VE, and also reduced the number of NVCs.

CONCLUSIONS AND IMPLICATIONS

CXCR2 and TRPV1 channels play important roles in cyclophosphamide-induced cystitis in rats and could provide potential therapeutic targets for cystitis.

Purification and biological activities of Abelmoschus esculentus seed lectin

The Abelmoschus esculentus (Malvaceae) plant originated in Africa and has spread across a number of tropic countries, including northeastern Brazil. The plant has been used to treat various disorders, such as cancer, microbial infections, hypoglycemia, constipation, urine retention and inflammation. The lectin of A. esculentus (AEL) was isolated by precipitation with ammonium sulfate at a saturation level of 30/60 and purified by ion exchange chromatography (Sephacel-DEAE). The electrophoresis (SDS-PAGE) profile of the AEL showed two protein bands of apparent molecular mass of approximately 15.0 and 21.0 kDa. The homogenity of the protein was confirmed by electrospray mass spectrometry (ESI-MS), which revealed the presence of a 10.29-kDa monomer and a 20.58-kDa dimer. The AEL exhibits agglutinating activity against rabbit (74.41 UH/mP) and human type ABO erythrocytes (21.00 UH/mP). This activity does not require the presence of divalent cations and is specifically inhibited by lactose, fructose and mannose. The intravenous treatment with 0.01, 0.1 and 1 mg/kg of AEL inhibited the paw edema elicited by carrageenan by approximately 15, 22 and 44 %, respectively, but not that induced by dextran. In addition, treatment with 0.1, 1 and 10 mg/kg of AEL also inhibited the abdominal writhing induced by acetic acid by approximately 52, 57 and 69 %, respectively. In conclusion, AEL is a new lectin with a molecular mass of 20.0 kDa, which is -composed of a 10.291-Da monomer and a 20.582-kDa dimer, that exhibits anti-inflammatory, antinociceptive and hemagglutinating activities. In addition, the lectin hemagglutinating property is both metallo-independent and associated with the lectin domain.

Anti-inflammatory and antimicrobial evaluation of neovestitol and vestitol isolated from Brazilian red propolis

The objective of this study was to evaluate anti-inflammatory and antimicrobial activities of neovestitol and vestitol isolated from Brazilian red propolis (BRP). BRP ethanolic extract (EEP), neovestitol, and vestitol were evaluated by anti-inflammatory properties using a neutrophil migration assay. The antimicrobial activity was evaluated by minimal inhibitory and bactericidal concentrations (MIC and MBC) against Streptococcus mutans , Streptococcus sobrinus , Staphylococcus aureus , and Actinomyces naeslundii . Neovestitol, vestitol, and EEP inhibited neutrophil migration at a dose of 10 mg/kg. Regarding antimicrobial activity, neovestitol showed MICs ranging from <6.25 to 25-50 μg/mL and MBCs ranging from 25-50 to 50-100 μg/mL, while vestitol showed MICs ranging from 25-50 to 50-100 μg/mL and MBCs ranging from 25-50 to 50-100 μg/mL. Both isoflavonoids neovestitol and vestitol are consistent bioactive compounds displaying anti-inflammatory and antimicrobial activities that can strongly act in a low dose and concentration and have a promising potential to be applied in the pharmaceutical and food industries.

Antinociceptive and anti-inflammatory effects of a lectin-like substance from Clitoria fairchildiana R. Howard seeds

Lectins are proteins that have the ability to bind specifically and reversibly to carbohydrates and glycoconjugates, without altering the structure of the glycosyl ligand. They are found in organisms such as viruses, plants and humans, and they have been shown to possess important biological activities. The objective of this study was to purify and characterize lectins in the seeds of Clitoria fairchildiana, as well as to verify their biological activities. The results indicated the presence of a lectin (CFAL) in the glutelin acid protein fraction, which agglutinated native rabbit erythrocytes. CFAL was purified by column chromatography ion-exchange, DEAE-Sephacel, which was obtained from a peak of protein retained in the matrix by applying 0.5 M NaCl using the step-wise method. Electrophoretic analysis of this lectin in SDS-PAGE indicated a two band pattern protein molecular mass of approximately 100 and 116 kDa. CFAL proved to be unspecific to all carbohydrates/glycoconjugates in common use for the sugar inhibition test. This lectin showed no significant cytotoxicity to human red blood cells. It was observed that CFAL has anti-inflammatory activity in the paw edema induced by carrageenan model, in which a 64% diminution in edema was observed. Antinociceptive effects were observed for CFAL in the abdominal writhing test (induced by acetic acid), in which increasing doses of the lectin caused reduction in the number of contortions by up to 72%. It was concluded that the purified and characterized lectin from the seeds of Clitoria fairchildiana has anti-inflammatory and antinociceptive activity, and is not cytotoxic to human erythrocytes.

Effects of the compounds MV8608 and MV8612 obtained from Mandevilla velutina in the model of hemorrhagic cystitis induced by cyclophosphamide in rats

Hemorrhagic cystitis (HC) is a common side effect observed in patients under chemotherapy with cyclophosphamide (CYP). The urotoxic side effects of CYP are attributed to the metabolic compound acrolein, and can be partially prevented by the uroprotector agent 2-mercaptoethene sulfate (Mesna). The present study analyzed the anti-inflammatory and the antinociceptive effects of compounds MV8608 and MV8612 obtained from Mandevilla velutina in the rat model of CYP-induced HC. Male Wistar rats were used (six to eight per group, 220-250 g). HC was induced by a single administration of CYP (100 mg/kg, ip). Three behavioral parameters--breathing rate, closing of the eyes, and specific posture--were used as nociception indexes, and scored at different time intervals (15-180 min) after cystitis induction. As inflammatory parameters, hemorrhage presence, edema formation, and bladder weight were determined at 24 h after CYP administration. The neutrophil migration was assessed by means of myeloperoxidase (MPO activity), 4 h after cystitis induction. As expected, Mesna treatment was able to reduce in a significant manner all the inflammatory and the nociceptive parameters induced by CYP. Of note, the administration of MV8608 significantly inhibited the hemorrhage formation and the neutrophil recruitment, while the MV8612 treatment markedly reduced the bladder weight, without interfering with neutrophil influx. Interestingly, the treatment with either MV8608 or MV8612 markedly reduced the nociceptive responses. The present results clearly indicate that MV8608 and MV8612 might represent important alternatives to prevent side effects, especially the nociception, following chemotherapy with CYP.

Vasodilator effects of Diocleinae lectins from the Canavalia genus

This study investigated and compared vascular actions of leguminous lectins obtained from the Canavalia genus (Canavalia brasiliensis, Canavalia gladiata, and Canavalia maritima) in the rat models of paw edema and isolated aorta. Paw edema was induced by subcutaneous injection of lectins (0.01-1 mg/kg) in animals pre-treated or not with indomethacin or L-NAME. In isolated aorta, cumulative concentration curves of C. gladiata or C. brasiliensis (1-100 microg/ml) were performed at the contraction plateau induced by phenylephrine or at tissue basal tonus. The mechanism of the lectin relaxant action was investigated by previous addition of L-NAME, indomethacin, or tetraethylammonium. In both models, the lectin domain involvement was evaluated by incubation of lectins with their ligand and non-ligand sugars. The lectins induced paw edema paralleled by protein leakage. The edematogenic activity elicited by C. gladiata and C. brasiliensis involves prostaglandins and nitric oxide (NO), while that of C. maritima occurs without NO interference. C. gladiata and C. brasiliensis elicited aorta relaxation involving NO and prostacyclin, while that of C. gladiata included EDHF. All lectin effects were prevented by their binding sugars. The present study demonstrated important vasodilator effects of different degrees and mechanisms in vivo and in vitro of Canavalia lectins. In vivo, the edematogenic activity was paralleled by plasma exudation, and in vitro, aorta relaxation was strictly dependent on intact endothelium. All effects occurred via interaction with lectin domains and participation of NO and/or prostanoids.

Involvement of NO in the inhibitory effect of Calotropis procera latex protein fractions on leukocyte rolling, adhesion and infiltration in rat peritonitis model

AIM OF THE STUDY

The latex of Calotropis procera has been used in the traditional medicinal system for the treatment of leprosy, ulcers, tumors, piles and diseases of liver, spleen, abdomen and toothache. It comprises of a non-dialyzable protein fraction (LP) that exhibits anti-inflammatory properties and a dialyzable fraction (DF) exhibiting pro-inflammatory properties. The present study was carried out to evaluate the effect of LP sub-fractions on neutrophil functions and nociception in rodent models and to elucidate the mediatory role of nitric oxide (NO).

MATERIAL AND METHODS

The LP was subjected to ion exchange chromatography and the effect of its three sub-fractions (LP(PI), LP(PII) and LP(PIII)) thus obtained was evaluated on leukocyte functions in the rat peritonitis model and on nociception in the mouse model.

RESULTS

LP sub-fractions exhibit distinct protein profile and produce a significant decrease in the carrageenan and DF induced neutrophil influx and exhibit anti-nociceptive property. The LP and its sub-fractions produced a marked reduction in the number of rolling and adherent leukocytes in the mesenteric microvasculature as revealed by intravital microscopy. The anti-inflammatory effect of LP(PI), the most potent anti-inflammatory fraction of LP, was accompanied by an increase in the serum levels of NO. Further, our study shows that NO is also involved in the inhibitory effect of LP(PI) on neutrophil influx.

CONCLUSIONS

Our study shows that LP fraction of Calotropis procera comprises of three distinct sets of proteins exhibiting anti-inflammatory and anti-nociceptive properties of which LP(PI) was most potent in inhibiting neutrophil functions and its effects are mediated through NO production.

An anti-inflammatory lectin from Luetzelburgia auriculata seeds inhibits adhesion and rolling of leukocytes and modulates histamine and PGE2 action in acute inflammation models

OBJECTIVES

To study and characterize the in vivo effect of the lectin from Luetzelburgia auriculata seed on acute inflammation models.

METHODS

The lectin was purified from the crude saline extract by affinity chromatography on a guar-gum matrix. Native, heat-treated, and digested lectin was evaluated for anti-inflammatory activity by using peritonitis and paw edema models. The anti-inflammatory activity was characterized by intravital microscopy, nitric oxide production, and myeloperoxidase activity.

RESULTS

The lectin exhibited anti-inflammatory activity (2 mg/kg) on both models, reducing local myeloperoxidase activity. Galactose or heat treatment (100 degrees C, 10 min) reduced anti-inflammatory action. Anti-inflammation involves the inhibition of adhesion and rolling of leukocytes along with augmentation of nitric oxide in serum. The lectin inhibited the edematogenic effect of histamine and prostaglandins (PGE2) but did not alter the chemoattractant effect of IL-8.

CONCLUSIONS

The results indicate that this lectin is a potent anti-inflammatory molecule. Its effects engage diverse modulatory events.

Fucoidin prevents Clostridium difficile toxin-A-induced ileal enteritis in mice

Recent reports suggest increased incidence and severity of Clostridium difficile-associated diseases. These facts have raised the need for additional clarification of pathogenesis and for a search for new therapeutic strategies. This study evaluated the effects of the polysaccharide fucoidin, an L-selectin blocker, on toxin-A-induced mouse enteritis. Fucoidin (25 mg/kg) or saline (0.1 ml) were injected systemically (ocular plexus) 5 min prior to local challenge with toxin A (5 microg/ileal loop) or phosphate-buffered saline (PBS). Intestinal fluid volume/length and ileal loop weight/length ratios were calculated 3 h later. Ileal tissues were collected for histopathology and measurement of myeloperoxidase and adenosine deaminase activity. Fucoidin significantly (P < 0.05) prevented the toxin-A-induced increase in weight/length and volume/length ratios and reduced mucosal disruption, as shown in histopathology. Fucoidin also significantly (P < 0.05) reduced toxin-A-induced myeloperoxidase and adenosine deaminase activities. In conclusion, fucoidin reduces tissue injury and inflammation in toxin-A-induced mouse enteritis.

Lonchocarpus sericeus lectin decreases leukocyte migration and mechanical hypernociception by inhibiting cytokine and chemokines production

In this study, we tested the potential use of a lectin from Lonchocarpus sericeus seeds (LSL), to control neutrophil migration and inflammatory hypernociception (decrease of nociceptive threshold). Pretreatment of the animals intravenously (15 min before) with LSL inhibited neutrophil migration to the peritoneal cavity in a dose-dependent fashion confirmed by an inhibition of rolling and adhesion of leukocytes by intravital microscopy. We also tested the ability of the pretreatment with LSL to inhibit neutrophil migration on immunised mice, and it was observed that a strong inhibition of neutrophil migration induced by ovoalbumin in immunized mice. Another set of experiments showed that pretreatment of the animals with LSL, inhibited the mechanical hypernociception in mice induced by the i.pl. injection of OVA in immunized mice and of carrageenan in naïve mice, but not that induced by prostaglandin E(2) (PGE(2)) or formalin. This anti-nociceptive effect correlated with an effective blockade of neutrophil influx, as assessed by the hind paw tissue myeloperoxidase levels. In addition, we measured cytokines (TNF-alpha and IL-1beta) and chemokines (MIP-1alpha [CCL3] and KC [CXCL1]) from the peritoneal exudates and i.pl. tissue. Animals treated with LSL showed inhibition of cytokines and chemokines release in a dose-dependent manner. In conclusion, we demonstrated that the inhibitory effects of LSL on neutrophil migration and mechanical inflammatory hypernocicepetion are associated with the inhibition of the production of cytokines and chemokines.

Anti-asthmatic potential of a D-galactose-binding lectin from Synadenium carinatum latex

Extracts from the plant Synadenium carinatum latex are widely and indiscriminately used in popular medicine to treat a great number of inflammatory disorders and although the mechanisms underlying these effects remain undefined, the lectin isolated from S. carinatum latex (ScLL) is thought to be in part responsible for these anti-inflammatory effects. In order to elucidate possible immunoregulatory activities of ScLL, we investigated the effects of ScLL administration in models of acute and chronic inflammation. Oral administration of ScLL significantly inhibited neutrophil and eosinophil extravasation in models of acute and chronic inflammation and reduced eosinophil and mononuclear blood counts during chronic inflammation. ScLL administration reduced IL(interleukin)-4 and IL-5 levels but increased interferon-gamma and IL-10 in an asthma inflammatory model, which suggested that it might induce a TH2 to TH1 shift in the adaptive immune response. ScLL also inhibited IkappaBalpha degradation, a negative regulator of proinflammatory NF-kappaB. Taken together, these results provide the first description of a single factor isolated from S. carinatum latex extract with immunoregulatory functions and suggest that ScLL may be useful in the treatment of allergic inflammatory disorders.

Vatairea macrocarpa (Leguminosae) lectin activates cultured macrophages to release chemotactic mediators

The lectin from the legume Vatairea macrocarpa is a galactose/N-acetylgalactosamine binding protein that induced cellular inflammatory response mediated by resident cells. This study investigated which inflammatory mediators would be released from lectin-activated cells. The intraperitoneal injection in rats of the supernatant from cultured macrophages, but not from mast cells, stimulated with lectin induced a time- and dose-dependent release of a neutrophil chemotactic factor, termed MNCF-VML. Pharmacological modulation with dexamethasone inhibited both the lectin-induced chemotactic activity in vivo and also the lectin-induced release of MNCF-VML into the supernatant of cultured macrophages. Cyclooxygenase and lipoxygenase metabolites are apparently not involved in the action of this factor or its release, since indomethacin or MK886 were unable to affect the lectin response. The molecular weight of MNCF-VML was found to be greater than 5 kDa, which led to the investigation of which cytokine(s) could be involved by the following approaches: (a) treatment of animals with antiserum to tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-1, or IL-8 before intraperitoneal injection of lectin and (b) addition of antiserum to TNF-alpha, IL-1, or IL-8 to the supernatant of lectin-stimulated macrophages before intraperitoneal administration. Antiserum to TNF-alpha, but not IL-1 nor IL-8, inhibited the neutrophil migration induced either by lectin or MNCF-VML. Our data suggest that neutrophil migration induced by V. macrocarpa lectin occurs via the release of cytokines such as TNF-alpha by macrophages. Thus, this lectin may represent an important tool to better understand pathological situations where an excess of leukocytes at inflammatory sites causes tissue injury.

Purification and biological effects of Araucaria angustifolia (Araucariaceae) seed lectin

This paper describes the purification and characterization of a new N-acetyl-d-glucosamine-specific lectin from Araucaria angustifolia (AaL) seeds (Araucariaceae) and its anti-inflammatory and antibacterial activities. AaL was purified using a combination of affinity chromatography on a chitin column and ion exchange chromatography on Sephacel-DEAE. The pure protein has 8.0kDa (SDS-PAGE) and specifically agglutinates rabbit erythrocytes, effect that was independent of the presence of divalent cations and was inhibited after incubation with glucose and N-acetyl-d-glucosamine. AaL showed antibacterial activity against Gram-negative and Gram-positive strains, shown by scanning electron microscopy. AaL, intravenously injected into rats, showed anti-inflammatory effect, via carbohydrate site interaction, in the models of paw edema and peritonitis. This lectin can be used as a tool for studying bacterial infections and inflammatory processes.

Modulation of acute inflammation by a chitin-binding lectin from Araucaria angustifolia seeds via mast cells

The effects of a lectin (AaL) from seeds of Araucaria angustifolia were investigated in the model of rat paw edema. In vivo anti-and pro-inflammatory activities, role of sugar residues, inflammatory mediators and systemic toxicity were assessed. Intravenous injection of AaL (0.1-1 mg/kg) dose-dependently inhibited the dextran-induced increase in edema and vascular permeability, which were prevented by association of the lectin with its binding sugar N-acetyl-glucosamine (Glyc-Nac). AaL also significantly inhibited edema induced by serotonin (18%) and compound 48/80 (33%), but not edema induced by histamine. In contrast, when applied by the s.c. route, AaL evoked a paw edema that peaked 1 h later and was partially prevented by association with Glyc-Nac (59%) or by prior i.v. administration of the lectin itself (38.8%). This AaL edematogenic activity was significantly inhibited by pentoxifylline (44.4%) or dexamethasone (51%) and also by depletion of rat paw mast cells (45.6%), but not by L-N-nitro-arginine methyl ester or indomethacin, excluding involvement of nitric oxide and prostaglandins. Treatment of animals with a single anti-inflammatory dose of AaL (1 mg/kg, i.v.) for 7 days did not affect rat corporal mass, liver, kidney, spleen or stomach wet weight, blood leukocyte count, and urea, creatinine or serum transaminase activity. Systemic toxicity was apparent only at much higher doses (LD50=88.3 mg/kg) than those required for the anti-inflammatory effect. Summarizing, AaL exerts anti-and pro-edematogenic actions via interaction with its specific lectin domain. These actions may share a common pathway involving either activation or inhibition of inflammatory mediators from resident mast cells.

Crystal structure of a lectin from Canavalia maritima (ConM) in complex with trehalose and maltose reveals relevant mutation in ConA-like lectins

The crystal structure of Canavalia maritima lectin (ConM) complexed with trehalose and maltose revealed relevant point mutations in ConA-like lectins. ConM with the disaccharides and other ConA-like lectins complexed with carbohydrates demonstrated significant differences in the position of H-bonds. The main difference in the ConM structure is the replacement of Pro202 by Ser202, a residue that promotes the approximation of Tyr12 to the carbohydrate-binding site. The O-6' of the second glucose ring in maltose interacts with Tyr12, while in trehalose the interaction is established by the O-2' and Tyr12, explaining the higher affinity of ConM for disaccharides compared to monosaccharides.

Native crystal structure of a nitric oxide-releasing lectin from the seeds of Canavalia maritima

Here, we report the crystallographic study of a lectin from Canavalia maritima seeds (ConM) and its relaxant activity on vascular smooth muscle, to provide new insights into the understanding of structure/function relationships of this class of proteins. ConM was crystallized and its structure determined by standard molecular replacement techniques. The amino acid residues, previously suggested incorrectly by manual sequencing, have now been determined as I17, I53, S129, S134, G144, S164, P165, S187, V190, S169, T196, and S202. Analysis of the structure indicated a dimer in the asymmetric unit, two metal binding sites per monomer, and loops involved in the molecular oligomerization. These confer 98% similarity between ConM and other previously described lectins, derived from Canavalia ensiformis and Canavalia brasiliensis. Our functional data indicate that ConM exerts a concentration-dependent relaxant action on isolated aortic rings that probably occurs via an interaction with a specific lectin-binding site on the endothelium, resulting in a release of nitric oxide.

Helianthus tuberosus agglutinin directly induces neutrophil migration, which can be modulated/inhibited by resident mast cells

We investigated the effect of Helianthus tuberosus agglutinin (HTA) on neutrophil migration in vivo and in vitro. The role of resident cells in this effect was analyzed. Peritonitis was induced by injecting stimuli into rat (150–200 g) peritoneal cavities, and in vitro neutrophil chemotaxis was performed using a Boyden microchamber. HTA (80, 200, or 500 µg/mL per cavity) induced significant in vivo neutrophil migration (p < 0.05); in vitro assays showed that this lectin also induced neutrophil chemotaxis, an effect inhibited by the incubation of lectin associated with α-D(+)-mannose, its specific binding sugar. Depletion of the resident-cell population by peritoneal lavage did not alter HTA-induced neutrophil migration (200 µg/mL per cavity). The opposite strategy, increasing peritoneal macrophages by intraperitoneally injecting rats with thioglycollate, did not enhance the neutrophil migration produced by HTA (200 µg/mL per cavity). In addition, injection of supernatant from HTA-stimulated macrophage culture (300 µg/mL) into rat peritoneal cavities did not induce neutrophil migration. However, reduction of the peritoneal mast-cell population potentiated the neutrophil migration (p < 0.05) induced by HTA (200 µg/mL per cavity). Lectin from H. tuberosus has a direct neutrophil chemotatic effect that is modulated by mast cells.Key words: lectins, inflammation, Helianthus tuberosus, neutrophil migration.

Pro-inflammatory effect of Arum maculatum lectin and role of resident cells

Arum maculatum agglutinin (AMA) is a monocot lectin isolated from tubers of Arum maculatum L. (Araceae) which exhibits different specificity towards oligo-mannosidic-type and N-acetyllactosaminic-type glycans. We have investigated the effect of this lectin on the cells of the immune system. Models of neutrophil migration in vivo, neutrophil chemotaxis in vitro and macrophage cultures were used to study the lectin inflammatory activity. When administered into rat peritoneal cavities, AMA (80, 200 and 500 microg/mL/cavity) induced significant and dose-dependent neutrophil migration. This effect was inhibited by incubation with alpha-methyl-d-mannoside. A 83% depletion in the number of resident cells following peritoneal lavage did not reduce the AMA-induced neutrophil migration, as compared to sham animals (not washed). However, pre-treatment with 3% thioglycolate which increases the peritoneal macrophage population by 236%, enhanced the neutrophil migration induced by AMA (200 microg/mL/cavity) (119%, p < 0.05). Reduction of peritoneal mast cell population by chronic treatment of cavities with compound 48/80 did not modify AMA-induced neutrophil migration. The neutrophil chemotaxy assay in vitro shows that the lectin (300 microg/mL) induces neutrophil chemotaxy (368% p < 0.05) compared to RPMI. Finally, injection into peritoneal cavities of supernatants from macrophage cultures obtained after stimulation with AMA (300 microg/mL) enhanced neutrophil migration (110% p < 0.05). Summarizing, our data suggest that A. maculatum agglutinin presents pro-inflammatory activity, inducing neutrophil migration by two ways, one which is independent on resident cells and another one dependent on the presence of these cells.

Red marine alga Bryothamnion triquetrum lectin induces endothelium-dependent relaxation of the rat aorta via release of nitric oxide

We have investigated the vascular relaxant effects of the lectin from a red marine alga Bryothamnion triquetrum (BTL), in particular, the endothelial-dependency and the participation of a specific glycoprotein-binding site. BTL (1-100 microg mL(-1)) was applied to rat isolated aortic rings, with or without endothelium, tonically precontracted with phenylephrine (0.1 microM). Endothelium-dependent relaxation was assessed in the presence of indometacin (10 microM), L-nitro arginine methyl ester (L-NAME, 100 microM) and tetraethylammonium (TEA, 500 microM). For the involvement of the glycoprotein-binding site, BTL was assayed in presence of mucin (300 microg mL(-1)) or N-acetyl D-glucosamine (GlcNAc; 300 microg mL(-1)), a specific and non-specific lectin-binding sugar, respectively. BTL fully and concentration dependently relaxed preparations that possessed an intact endothelium (IC50 (concn producing 50% contraction) = 12.1 +/- 1.6 microg mL(-1)), whereas no significant relaxation was observed in endothelial-denuded tissue. L-NAME, but not indometacin or TEA, completely inhibited the lectin relaxation, suggesting the involvement of nitric oxide (NO). The lectin in association with mucin, but not with GlcNAc, inhibited BTL-induced relaxation, implicating the involvement of the lectin binding site. Our data suggest that the relaxant effect of the red marine alga Bryothamnion triquetrumlectin on isolated aorta occurs via interaction with a specific lectin-binding site on the endothelium, resulting in a release of NO.

Ternatin, a flavonoid, prevents cyclophosphamide and ifosfamide-induced hemorrhagic cystitis in rats

To compare the classical uroprotective efficacy of mesna (2-mercaptoethanesulfonic acid) with ternatin (flavonoid isolated from Egletes viscosa Less.) in cyclophosphamide (CYP) and ifosfamide (IFS) induced hemorrhagic cystitis (HC). Male Wistar rats received an intraperitoneal injection of saline, CYP or IFS and were treated with saline or mesna, 5 min before, 4 and 8 h after CYP or IFS administration. In other animals, 1, 2 or 3 doses of mesna were replaced with ternatin or 3 doses of mesna were replaced with dimethylsulphoxide (DMSO), ternatin diluent. In an additional group, the last 2 doses of mesna were replaced with saline. HC was evaluated 24 h after CYP or IFS administration. CYP or IFS treatment induced marked changes in macroscopic and microscopic evaluation and in bladder wet weight (BWW), and these alterations were significantly inhibited by treatment with 3 doses of mesna, as well as by the replacement of 1 or 2 doses of mesna with ternatin. The replacement of 2 doses of mesna with saline or all doses of mesna with ternatin or DMSO did not prevent HC. In conclusion, the replacement of 1 or 2 doses of mesna with ternatin efficiently blocked CYP- or IFS-induced HC, however mesna is necessary for initial uroprotection.

The galactose-binding lectin from Vatairea macrocarpa seeds induces in vivo neutrophil migration by indirect mechanism

To explore the pathways by which lectins induce an inflammatory response, the lectin from Vatairea macrocarpa (VML) seeds was used to induce neutrophil migration in rats. The lectin was shown to cause cell migration, with the effect partially blocked when galactose was added to inhibit lectin activity. Neutrophil migration was also reduced when peritoneal cavity of the animals was depleted of their resident cells beforehand, suggesting that neutrophil migration was mediated by an indirect mechanism. Pre-treatment of rats with thioglycollate increased recruitment of neutrophils while depletion of mast cells by the addition of compound 48/80 had little effect on neutrophil infiltration, suggesting the involvement of macrophages in the inflammatory process induced by the lectin. Inhibition of the cyclooxigenase, leukotriene and PAF activities by indomethacin, MK886 and BN50730, respectively, did not modify the pro-inflammatory effect previously observed. However, dexamethasone and thalidomide significantly reduced the population of neutrophils in the peritoneal cavity after lectin injection. The present study suggests that the effects produced by a galactose-binding lectin do not involve lipoxygenase, cyclooxygenase or PAF mediators that are well known to be involved in the inflammatory process. The blocking actions of dexamethasone and thalidimide suggest that as yet unidentified pro-inflammatory mediators are involved.

Use of dexamethasone with mesna for the prevention of ifosfamide-induced hemorrhagic cystitis

AIM

Hemorrhagic cystitis (HC) is a limiting side-effect of chemotherapy with ifosfamide (IFS). In the study presented here, we investigated the use of dexamethasone in combination with mesna for the prevention of IFS-induced HC.

METHODS

Male Wistar rats (150-200 g; 6 rats per group) were treated with saline or mesna 5 min (i.p.) before and 2 and 6 h after (v.o.) administration of IFS. One, two or three doses of mesna were replaced with dexamethasone alone or with dexamethasone plus mesna. Cystitis was evaluated 24 h after its induction by the changes in bladder wet weight and by macroscopic and microscopic analysis.

RESULTS

The replacement of the last dose or the last two doses of mesna with dexamethasone reduced the increase in bladder wet weight induced by IFS by 84.79% and 89.13%, respectively. In addition, it almost abolished the macroscopic and microscopic alterations induced by IFS. Moreover, the addition of dexamethasone to the last two doses of mesna was more efficient than three doses of mesna alone when evaluated microscopically.

CONCLUSION

Dexamethasone in combination with mesna was efficient in blocking IFS-induced HC. However, the replacement of last two doses of mesna with saline or all of the mesna doses with dexamethasone did not prevent HC.