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Interferons (IFNs)1 are a family of multifunctional cytokines that block viral infection, inhibit cell proliferation, and modulate cell differentiation. Whereas type I IFNs (IFN-␣, IFN-␤, and IFN-) bind to a common cell-surface receptor, the receptor for type II IFN (IFN-␥) is a distinct entity (1). IFNs transduce signals from the cell surface, resulting in selective gene induction through the activation of JAK tyrosine kinases and STAT transcription factors (1-3). Upon JAK-mediated tyrosine phosphorylation, the STAT proteins (STAT1, STAT2, and STAT3) dimerize and translocate to the nucleus to activate transcription of IFN-stimulated genes (3). IFN also activates the nuclear factor-B (NF-B) transcription factor in a serine/threonine kinase-dependent signaling pathway that protects cells against apoptosis (4, 5).NF-B regulates the expression of genes involved in cell signaling, stress responses, growth, survival, and apoptosis by binding to cis-acting B sites in the promoters and enhancers of these genes. Viruses, cytokines, lipopolysaccharides, and other stimulating agents promote NF-B translocation to the nucleus and DNA binding. Active DNA-binding forms of NF-B are dimeric combinations of Rel proteins (p50, p52, c-Rel, v-Rel, RelA/p65, and RelB). In most cell types, the predominant form of NF-B is the p50⅐p65 heterodimer. NF-B dimers are retained in the cytoplasm of unstimulated cells in an inactive state by the binding of a family of inhibitory IB proteins.Whereas STAT proteins play crucial roles in the transcriptional response to IFN-␣/␤ and in the induction of antiviral activity, the role of NF-B in IFN signaling and action has not been studied extensively. To identify the functional role of NF-B in IFN action, sensitivity to the antiviral effect of IFN was examined in fibroblasts that either had normal NF-B function or had a functional deletion of the IFN-induced NF-B pathway by germ line disruption of the Rel p50 and p65 proteins. Antiviral assays demonstrated that NF-B knockout (KO) fibroblasts were sensitized to the antiviral action of IFN-␤. To determine the relationship between gene regulation by IFN-␤ and antiviral activity, microarray analysis was performed on RNA samples collected from IFN-treated murine fibroblasts. Microarray analysis identified several classical IFN-stimulated genes (ISGs) involved in the antiviral action of IFN. Quantitative real-time PCR demonstrated that, whereas the IFN-induced expression of some ISGs was enhanced in NF-B KO cells relative to mouse wild-type fibroblasts, the IFN-induced expression of other ISGs was lower in NF-B KO cells. Our results demonstrate the distinctive role of NF-B in the regulation of ISGs and in the induction of antiviral activity. Thus, the IFN-activated NF-B pathway not only counterbalances apoptosis, but also regulates the expression of ISGs and the induction of antiviral activity. EXPERIMENTAL PROCEDURESBiological Reagents and Cell Culture-Recombinant Chinese hamster ovary cell-expressed rat IFN-␤ was obtained from Biogen Idec, Inc. (6). The b...

This research investigated the effect of enzymatically digested low molecular weight (MW) chitosan oligosaccharide on type 2 diabetes prevention. Three different chitosan oligosaccharide samples with varying MW were evaluated in vitro for inhibition of rat small intestinal α-glucosidase and porcine pancreatic α-amylase (GO2KA1; <1000 Da, GO2KA2; 1000–10,000 Da, GO2KA3; MW > 10,000 Da). The in vitro results showed that all tested samples had similar rat α-glucosidase inhibitory and porcine α-amylase inhibitory activity. Based on these observations, we decided to further investigate the effect of all three samples at a dose of 0.1 g/kg, on reducing postprandial blood glucose levels in Sprague-Dawley (SD) rat model after sucrose loading test. In the animal trial, all tested samples had postprandial blood glucose reduction effect, when compared to control, however GO2KA1 supplementation had the strongest effect. The glucose peak (Cmax) for GO2KA1 and control was 152 mg/dL and 193 mg/dL, respectively. The area under the blood glucose-time curve (AUC) for GO2KA1 and control was 262 h mg/dL and 305 h mg/dL, respectively. Furthermore, the time of peak plasma concentration of blood glucose (Tmax) for GO2KA1 was significantly delayed (0.9 h) compared to control (0.5 h). These results suggest that GO2KA1 could have a beneficial effect for blood glucose management relevant to diabetes prevention in normal and pre-diabetic individuals. The suggested mechanism of action is via inhibition of the carbohydrate hydrolysis enzyme α-glucosidase and since GO2KA1 (MW < 1000 Da) had higher in vivo effect, we hypothesize that it is more readily absorbed and might exert further biological effect once it is absorbed in the blood stream, relevant to blood glucose management.

BackgroundType 2 diabetes is a serious problem for developed countries. Prevention of prediabetes progression to type 2 diabetes with the use of natural products appears to a cost-effective solution. Previously we showed that enzymatically digested low molecular weight chitosan-oligosaccharide with molecular weight (MW) below 1,000 Da (GO2KA1) has potential for hyperglycemia management.MethodsIn this study we evaluated the effect of long-term supplementation of GO2KA1 on hyperglycemia using a db/db mice model. Additionally, we evaluated the effect of GO2KA1 on sucrase and glucoamylase activities and expression, using the same db/db mice model.ResultsAfter 42 days we observed that GO2KA1 supplementation reduced both the blood glucose level and HbA1c in a similar manner with a known anti-diabetic drug, acarbose. When the sucrase and glucoamylase activities of GO2KA1 and control mice were evaluated using enzymatic assay, we observed that GO2KA1 significantly inhibited sucrase in all 3 parts of the intestine, while glucoamylase activity was significantly reduced only in the middle and lower part. When the sucrase-isomaltase (SI) complex expression on mRNA level was evaluated, we observed that GO2KA1 had minimal inhibitory effect on the upper part, more pronounced inhibitory effect on the middle part, while the highest inhibition was observed on the lower part. Our findings suggest that long-term GO2KA1 supplementation in db/db mice results to significant blood glucose and HbA1c reduction, to levels similar with those of acarbose. Furthermore, our findings confirm previous in vitro observations that GO2KA1 has inhibitory effect on carbohydrate hydrolysis enzymes, namely sucrase, maltase and SI complex.ConclusionsResults from this study provide a strong rationale for the use of GO2KA1 for type 2 diabetes prevention, via inhibition of carbohydrate hydrolysis enzymes. Based on the findings of this animal trial, clinical trials will be designed and pursued.