In vitro and in vivo anti-inflammatory activities of high molecular weight sulfated polysaccharide; containing fucose separated from Sargassum horneri: Short communication

Recent studies on crude and pure compounds from Sargassum horneri have shown promising bioactive properties. However, anti-inflammatory potentials of fucose-rich sulfated polysaccharides from S. horneri have not yet been discovered. In the present study, we evaluated the in vitro and in vivo anti-inflammatory activities of four polysaccharide fractions separated from membrane filters according to their molecular weights (<5kDa (f1), 5-10kDa (f2), 10-30kDa (f3), and >30kDa (f4)). According to the results, F4 fraction inhibited the lipopolysaccharides (LPS)-induced nitric oxide (NO) (IC50=87.12μg/mL) and prostaglandin E2 production as well as pro-inflammatory cytokine production in RAW 264.7 cells through down-regulating nuclear factor-κB signaling cascade. According to the results, f4 has a potential to down-regulate LPS-induced toxicity, cell death and NO production levels in LPS-induced in vivo zebrafish embryo model. These results suggest that f4 fraction has the potential to develop functional materials or drugs to treat inflammatory diseases.

Dietary 2'-Fucosyllactose Enhances Operant Conditioning and Long-Term Potentiation via Gut-Brain Communication through the Vagus Nerve in Rodents

2´-fucosyllactose (2´-FL) is an abundant human milk oligosaccharide (HMO) in human milk with diverse biological effects. We recently reported ingested 2´-FL stimulates central nervous system (CNS) function, such as hippocampal long term potentiation (LTP) and learning and memory in rats. Conceivably the effect of 2´-FL on CNS function may be via the gut-brain axis (GBA), specifically the vagus nerve, and L-fucose (Fuc) may play a role. This study had two aims: (1) determine if the effect of ingested 2´-FL on the modulation of CNS function is dependent on the integrity of the molecule; and (2) confirm if oral 2´-FL modified hippocampal LTP and associative learning related skills in rats submitted to bilateral subdiaphragmatic vagotomy. Results showed that 2´-FL but not Fuc enhanced LTP, and vagotomy inhibited the effects of oral 2´-FL on LTP and associative learning related paradigms. Taken together, the data show that dietary 2´-FL but not its Fuc moiety affects cognitive domains and improves learning and memory in rats. This effect is dependent on vagus nerve integrity, suggesting GBA plays a role in 2´-FL-mediated cognitive benefits.

Locally administered antiproliferative drugs inhibit hypercontractility to serotonin in balloon-injured pig coronary artery

Although drugs such as sirolimus and paclitaxel are effective in reducing restenosis, their effects on vascular function are often overlooked. In this study, we have examined the effects of local delivery of several anti-restenotic drugs given in vivo after balloon injury on in vitro vascular contraction and relaxation 28 days after injury. Paclitaxel (50 microM), the farnesyl protein transferase inhibitor L744 (25 microM), sirolimus (25 microM) and Van 10/4 (decahydro-1,1,4,7-tetramethyl-1H-cycloprop[e]azulen-4-o-[2-(3-methylpent-2-enoyl)-fucopyranoside]; 25 microM) were delivered to porcine coronary arteries in vivo and the arteries removed 28 days later. Contractions to KCl and 5-hydroxytryptamine (5-HT) and relaxations to calcimycin and 3-morpholinosydnonimine (SIN-1) were measured in control (LCx) and balloon-injured (LAD) rings. In vehicle-infused coronary arteries, contraction to KCl and 5-HT was significantly enhanced 28 days after balloon injury, while the response to calcimycin had recovered fully, indicating endothelial regrowth. The response to SIN-1 was unchanged. None of the four drugs tested had any effect on the enhanced response to KCl 28 days after injury or on recovery of the calcimycin response. The hyper-responsiveness to 5-HT was eliminated by sirolimus, Van 10/4 and L744, but not paclitaxel. This study demonstrates that local drug infusion with structurally different antiproliferative drugs at the time of balloon angioplasty does not affect endothelial recovery and may in some cases prevent hyper-responsiveness to constrictor agents.

Leukocyte adhesion deficiency II: therapy and genetic defect

Leukocyte adhesion deficiency II (LAD II) is a rare congenital disease which is caused by a defect in fucosylation of glycoconjugates. Hypofucosylated structures include ligands for the selectin family of adhesion molecules. This results in a leukocyte adhesion defect causing an immunodeficiency. In addition, LAD II patients show severe mental and growth retardations suggesting a role of fucose in development. Recently, a LAD II patient was treated with oral supplementation of fucose. This simple therapy restored selectin ligands and corrected the immunodeficiency. However, in another patient the treatment protocol had no effect indicating that the biochemical defect in the latter patient is somewhat different. The genetic defect in LAD II has now been located to a gene encoding a GDP-fucose transporter which gates GDP-fucose into the Golgi where fucose is transferred onto glycoconjugates. Point mutations have been detected in this gene in several LAD II patients, which inactivate the transporter function. Thus, LAD II represents the first developmental and immune defect that is based on a malfunctioning nucleotide sugar transporter.

Successful treatment of Pseudomonas aeruginosa respiratory tract infection with a sugar solution--a case report on a lectin based therapeutic principle

BACKGROUND

Airway infections with Pseudomonas aeruginosa often represent a life-threatening event in immuno-compromised patients or patients with Cystic Fibrosis. The adhesion of this bacterium to surfaces such as the airway epithelium is mediated by two lectins, sugar binding proteins. In addition to their adhesive properties, these lectins have been shown to stop human ciliary beating thus compromising the mucociliary clearance as an important non-specific defence mechanism of the airways. Inhibition of these lectins by their specific sugars galactose and fucose, respectively, could therefore be of benefit in the elimination therapy of P. aeruginosa.

CASE REPORT

An infant suffering from P. aeruginosa airway infection after chemotherapy for neuroblastoma, which could not successfully be treated by antibiotics, was subjected to a series of additional galactose/fucose inhalations, which eliminated the germ as evidenced by microbiological testing. This is the first report suggesting the effectiveness of a lectin-based therapeutic principle in P. aeruginosa airway infection.

CONCLUSION

The competitive inhibition of P. aeruginosa lectins by the lectin specific sugars galactose and fucose may overcome particular mechanisms of bacterial resistance in patients with P. aeruginosa airway infection. This underlying biochemical mechanism and the outcome of our patient suggest a clinical benefit of this novel therapeutic approach for immunocompromised patients or patients with cystic fibrosis suffering from infection with P. aeruginosa.

Correction of leukocyte adhesion deficiency type II with oral fucose

We describe a simple, noninvasive, and effective therapy for leukocyte adhesion deficiency type II (LAD II), a rare inherited disorder of fucose metabolism. This disorder leads to an immunodeficiency caused by the absence of carbohydrate-based selectin ligands on the surface of neutrophils as well as to severe psychomotor and mental retardation. The fucosylation defect in LAD II fibroblasts can be corrected by addition of L-fucose to the culture medium. This prompted us to initiate dietary fucose therapy on a patient with LAD II. Oral supplementation of fucose in this patient induced the expression of fucosylated selectin ligands on neutrophils and core fucosylation of serum glycoproteins. During 9 months of treatment, infections and fever disappeared, elevated neutrophil counts returned to normal, and psychomotor capabilities improved.

Effect of leukocytes on corneal cellular proliferation and wound healing

PURPOSE

To establish whether fucoidin, by blocking the adhesion of leukocytes on the limbal vascular endothelium, prevents extravasation of the cells from the blood stream into the limbal stroma and the wounded area after corneal injury. Successful leukocyte blocking enabled investigation of the influence of leukocytes on corneal cellular proliferation after corneal wounding.

METHODS

Thirty-two New Zealand White rabbits were used. Photorefractive keratectomy (PRK) and a standardized alkali corneal wound were used as models in two sets of experiments. In half of the injured rabbits fucoidin was used to prevent leukocytes from leaving the local vessels. The efficiency of the blocking technique was evaluated by counting the number of leukocytes in the limbal and wounded corneal areas. Proliferating cell nuclear antigen (PCNA) was used as a marker for proliferative activity.

RESULTS

The infiltration of leukocytes into the limbus and the cornea after PRK and alkali injuries can be blocked by fucoidin. The healing rate of corneal epithelium after alkali burn was retarded in the absence of leukocytes. PCNA expression was enhanced in the presence of leukocytes. Fucoidin per se had no influence on corneal cell proliferation and wound healing.

CONCLUSIONS

Polymorphonuclear leukocytes (PMNs) can be prevented from entering the cornea in vivo by fucoidin after PRK and after alkali burn. The corneal epithelial healing rate is delayed in the absence of PMNs in vivo, and PCNA expression increases in the presence of leukocytes.

Augmentation of lithium's behavioral effect by inositol uptake inhibitors

Lithium inhibits the enzyme inositol monophosphatase and thus obstructs the enzymatic degradation of inositol triphosphate (IP3) to inositol in the phosphate-phosphoinositide (PIP) cycle. This inhibition may result in reduced availability of the second messengers IP3 and DAG that are derivates of the PIP cycle, and this action is currently a leading hypothesis regarding lithium's therapeutic and prophylactic effect in affective disorders. Inositol is also available to the cell by uptake from the intercellular matrix, and therefore it is possible that compounds that block the uptake may have lithium-like effects. To test this hypothesis, the present study evaluates the effects of two inositol uptake inhibitors, the carbohydrate L-fucose and the cyclodepsipeptide nordidemnin, in a behavioral model of pilocarpine-induced seizures known to be enhanced by lithium. We tested the possibility that L-fucose produces lithium-like effects, or that L-fucose or nordidemnin augment lithium's behavioral effects. Results indicate that acute ICV treatment with L-fucose did not by itself have a lithium-like effect in the behavioral model, but significantly augmented lithium's effect when combined with lithium treatment. Nordidemnin treatment showed similar effects. The results suggest that when inositol monophosphatase is inhibited by lithium, further restriction of cellular inositol availability may result in an augmentation of lithium's behavioral effects. It is possible that such manipulations may be applicable in the treatment of patients with affective disorders, especially patients who are poor responders to lithium monotherapy.

Reduced Na+/K+ adenosine triphosphatase activity and motor nerve conduction velocity in L-fucose-fed rats is reversible after dietary normalization

Development of early defects in diabetic neuropathy has been linked to metabolic abnormalities and is considered reversible. To further address some of the questions concerning the contribution by metabolic derangements to the development of neural defects and reversibility, we have developed an animal model, by feeding rats a diet containing 20% L-fucose, that develops neural defects similar to those that occur in streptozotocin-induced diabetic rats. After 6 weeks on a 20% L-fucose diet, myo-inositol content and Na+/K+ adenosine triphosphatase (ATPase) activity of the sciatic nerve were significantly reduced, as was the motor nerve conduction velocity (MNCV). L-Fucose is a monosaccharide that occurs in low concentrations in normal serum but is increased in diabetic patients. In cultured cells, L-fucose, at concentrations that occur in diabetic circulation, is a competitive inhibitor of myo-inositol uptake. The purpose of the present study was to compare the sequential pattern of the reversibility of the slowing of MNCV with ouabain-inhibited sciatic nerve Na+/K+ ATPase activity and myo-inositol content in rats fed a diet containing 20% L-fucose for a period of 6 weeks followed by a normal diet lasting up to 2 weeks. Unbound L-fucose levels in the serum returned to normal in less than 24 hours of the rats being placed on the normal diet. Normalization of slowed MNCV after removing L-fucose-fed rats from the L-fucose diet followed a pattern of recovery similar to the recovery of sciatic nerve ouabain-inhibited Na+/K+ ATPase activity, with complete recovery occurring within 7 days of the rats being placed on the normal diet. In contrast, myo-inositol content of the sciatic nerve remained decreased following 3 days on the normal diet, and required 14 days for complete normalization. Results from these studies suggest that a causal relationship may exist for reduced Na+/K+ ATPase activity and MNCV in L-fucose-fed rats, and that a measurable decrease in myo-inositol content may not be necessary for the development of these defects in the sciatic nerve.

2-deoxygalactose interferes with an intermediate processing stage of memory

The effect of 2-deoxygalactose (2-D-gal), an inhibitor of glycoprotein synthesis, on memory formation was investigated with the day-old chick trained on a single-trial passive discrimination task. 2-D-gal (10 mumol/chick) was shown to inhibit memory formation at a time before the emergence of an antibiotic-sensitive long-term memory stage. The amnestic effect of 2-D-gal was successfully prevented by galactose, and more significantly by noradrenaline. In contrast, anisomycin-induced amnesia was resistant to challenge by either galactose or noradrenaline. The results are consistent with the view that some glycoprotein involvement in memory formation occurs prior to the formation of protein synthesis-dependent long-term memory, and this role of glycoproteins may be associated with the triggering of long-term memory formation by noradrenaline.

Fucose and fucose-containing sugar epitopes enhance hippocampal long-term potentiation in the freely moving rat

Male Wistar rats were intrahippocampally injected with L-fucose and the sugar epitope 2'-fucosyl-lactose prior to induction of long-term potentiation (LTP). Both substances had only a minimal and short-lasting depressive effect on the monosynaptically evoked field potential recorded in the dorsal blade of the dentate gyrus of freely moving rats upon stimulation of the perforant pathway. However, LTP induced by fractionated tetanization of the perforant pathway, which declined within 24 h in control animals injected with Lactose, remained at the initial level even 48 h after tetanization (difference to the control group significant with P < 0.01). The results support earlier findings which have indicated a participation of fucosylated macromolecules in the maintenance of LTP. Different molecular mechanisms concerning the effect of both substances and the significance of the data in elucidation of the relationship between LTP and memory formation are discussed.

Reduced motor nerve conduction velocity and Na(+)-K(+)-ATPase activity in rats maintained on L-fucose diet. Reversal by myo-inositol supplementation

L-Fucose is a monosaccharide that occurs in low concentrations in normal serum but has been shown to be increased in diabetic individuals. In cultured mammalian cells, L-fucose is a potent competitive inhibitor of myo-inositol transport. Abnormal myo-inositol metabolism has been proposed to be a factor in the development of diabetic complications. To test the hypothesis that myo-inositol deficiency may be responsible for the electrophysiological and biological defects in diabetic neuropathy, rats were fed a diet containing 10 or 20% L-fucose for a period of 6 wk. After 3 wk, the L-fucose diets in two groups of rats were supplemented with 1% myo-inositol. At the end of the study protocol, motor nerve conduction velocity, sciatic nerve tissue Na(+)-K(+)-ATPase activity, and myo-inositol content were determined. These results were compared with those of STZ-induced diabetic rats fed either a normal diet or a diet containing 1% myo-inositol or with those given 450 mg/kg body wt of sorbinil. Serum L-fucose levels were significantly increased in rats fed a diet containing 10 or 20% L-fucose. In comparison, the serum L-fucose levels in the diabetic rats were increased to a lesser extent. Motor nerve conduction velocity was significantly slower in rats fed a 10 or 20% L-fucose diet. Sciatic nerve composite and ouabain-sensitive Na(+)-K(+)-ATPase activity and myo-inositol content was also significantly decreased. Supplementation of 1% myo-inositol to the L-fucose-containing diet restored nerve myo-inositol levels and significantly improved Na(+)-K(+)-ATPase activity and motor nerve conduction velocity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of p-xylene inhalation on axonal transport in the rat retinal ganglion cells

Although the solvent xylene is suspected of producing nervous system dysfunction in animals and humans, little is known regarding the neurochemical consequences of xylene inhalation. The intent of this study was to determine the effect of intermittent, acute, and subchronic p-xylene exposure on the axonal transport of proteins and glycoproteins within the rat retinofugal tract. A number of different exposure regimens were tested ranging from 50 ppm for a single 6-hr exposure to 1600 ppm 6 hr/day, 5 days/week, for a total of 8 exposure days. Immediately following removal from the inhalation chambers rats were injected intraocularly with [35S]methionine and [3H]fucose (to label retinal proteins and glycoproteins, respectively) and the axonal transport of labeled macromolecules to axons (optic nerve and optic tract) and nerve endings (lateral geniculate body and superior colliculus) was examined 20 hr after precursor injection. Only relatively severe exposure regimens (i.e., 800 or 1600 ppm 6 hr/day, 5 days/week, for 1.5 weeks) produced significant reductions in axonal transport; there was a moderate reduction in the axonal transport of 35S-labeled proteins in the 800-ppm-treated group which was more widespread in the 1600 ppm-treated group. Transport of 3H-labeled glycoproteins was less affected. Assessment of retinal metabolism immediately after isotope injection indicated that the rate of precursor uptake was not reduced in either treatment group. Furthermore, rapid transport was still substantially reduced in animals exposed to 1600 ppm p-xylene and allowed a 13-day withdrawal period. These data indicate that p-xylene inhalation decreases rapid axonal transport supplied to the projections of the rat retinal ganglion cells immediately after cessation of inhalation exposure and that this decreased transport is still apparent 13 days after the last exposure. This decreased supply of cellular materials to the axon and nerve ending regions could initiate the neuronal malfunction reported in solvent-exposed animals and humans.

Evidence that an L-fucose-containing component in the beta-cell plasma membrane is involved in the regulation of glucose-induced insulin release

The effect of the L-fucose-selective lectin Ulex Europeus I (UEA I), a blocker of the Na+, K+, Cl- co-transport system in the kidney, was tested on insulin secretion from isolated beta-cell-rich pancreatic islets. UEA I at doses from 50 to 100 micrograms ml-1 significantly reduced the glucose-induced (20 mmol l-1) insulin release whereas the basal (3 mmol l-1) release was unaffected. The inhibitory effect of 100 micrograms ml l-1 UEA I was completely abolished by 10 mmol l-1 L-fucose. The data suggest that an L-fucose-containing structure in the beta-cell plasma membrane participates in the regulation of glucose-induced insulin release. This structure may be similar to the L-fucose-containing glycoprotein in the kidney tubules that is believed to be the Na+, K+, Cl- cotransporter.

Suppression of the elicitation phase of contact allergy by epicutaneous application of alpha-L-fucose

Local application of alpha-L-fucose on the ear before elicitation of contact allergy to dinitrofluorobenzene (DNFB) in BALB/c mice results in a suppression of the contact allergic response. However, local application of alpha-L-fucose at the sensitization site on the abdominal wall before sensitizing the animals with DNFB had no inhibitory effect on contact allergy. Alpha-L-fucose has been demonstrated to inhibit lymphokine activity in vitro and manifestation of cellular immunity in vivo. Our results suggest that alpha-L-fucose suppresses contact allergy by locally inhibiting the efferent phase of the cellular immune response.

The metabolism of nerve terminal glycoproteins in the rat brain

The fate of [3H]fucose in subcellular fractions has been followed for a period of three weeks after intraventricular injection in the rat brain. Isolated synaptosomal membranes were examined by gel electrophoresis. Seven fucosyl glycoproteins with molecular weights ranging from 123,000 to 31,000 were detected by scintillation counting of transversely sliced gels and their specific activities determined. The half-lives of 6 of the membrane glycoproteins fell within the range 11-22 days. The smallest glycoprotein showed anomalous behaviour; its radioactivity did not fall significantly over the period of study. The results are discussed in relation to current concepts of fast axonal transport.