Diabetes is a chronic and progressive disease with continuously increasing prevalence, rising financial pressure on the worldwide healthcare systems. Recently, the insulin resistance, hallmark of type 2 diabetes, was cured in mice treated with NAD+ precursor β-nicotinamide mononucleotide (NMN), no toxic effects being reported. However, NMN has a high price tag, more cost effective production methods are needed. This study proposes a biotechnological NMN production method in Escherichia coli. We show that bicistronic expression of recombinant nicotinamide phosphoribosyl transferase (Nampt) and phosphoribosyl pyrophosphate (PRPP) synthetase in the presence of nicotinamide (NAM) and lactose may be a successful strategy for cost effective NMN production. Protein expression vectors carrying NAMPT gene from Haemophilus ducreyi and PRPP synthetase from Bacillus amyloliquefaciens with L135I mutation were transformed in Escherichia coli BL21(DE3)pLysS. NMN production reached a maximum of 15.42 mg per L of bacterial culture (or 17.26 mg per gram of protein) in these cells grown in PYA8 medium supplemented with 0.1% NAM and 1% lactose.

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During recurrent infections associated with CF, exocrine MPs may contribute to endocrine cell dysfunction via NF-κB pathways. Membrane CFTR dysfunction is associated with decreased insulin secretion.

The nonenzymatic attachment of sugars to proteins, namely glycation, is accelerated under diabetic conditions. Monitoring the glycated human serum albumin (HSA) levels gives the short term variation of glucose concentration in diabetic patients blood. Therefore, a significant effort was made to measure glycated HSA, including by spectroscopic methods such as Raman. Here we used THz spectroscopy to monitor HSA glycation in time (over 5, 7 and 11 weeks). Different sugar types have different reactivity; therefore we also addressed the reducing sugar influence on glycation by performing in vitro HSA glycation by both glucose and fructose. Since residues protonation state influences their susceptibility for glycation, we incubated HSA with sugars at two pH values: 7 and 8. Our results show that THz absorption decreases with the incubation time of HSA with sugars. At the incubation times we considered, the most significant differences were obtained on HSA samples glycated using glucose. Differences between samples glycated by glucose and by fructose show that glycation by glucose is a slower process. At pH 7, glycation by glucose is slower than at pH 8, while glycation by fructose is slightly faster at pH 7 than at pH 8. Glycated HSA models with different degrees of glycation were built by molecular modeling. Simulated THz spectra of the models are in good agreement with the experimental data. All these show that THz spectroscopy could monitor the progression of glycation in time and that it is sensitive to reducing sugars or pH value used in the glycation process.

Many polysaccharides and polysaccharide-protein complexes isolated from mushrooms have immunomodulatory and anti-cancer effects. Our aim was to study the regulatory mechanisms of Caco-2 cell response to water soluble P. ostreatus polysaccharide extract up to 72 hours. Specific enzymatic activities were assessed by kinetic measurements. The reduced glutathione content and the lipid peroxidation level were also analyzed. Protein expression of several heat shock proteins, Bcl-2 and metalloproteinases 2 and 9 were revealed by Western blot. Gelatin zymography assay was used to evaluate the MMP-2 and MMP-9 activities. Until the third day of exposure the total SOD activity decreased continuously by 30%, whereas GST and GR ones diminished by 17% respectively 30.5% compared to control. No significant changes were observed in CAT and G6PDH specific activities as well as in GSH and MDA concentration. After the third day of exposure a significant up-regulation of Hsp60 and Hsp90 expression and a down-regulation of Hsp70 one were registered. Bcl-2 protein levels were down-regulated by 50% in the first day of treatment but increased after 3 days. MMP-2 and 9 secretion in the culture medium was significantly reduced suggesting a diminished ability of invasion of colon cancer cells. Our data revealed that in vitro treatment with P. ostreatus aqueous polysaccharide extract does not induce apoptosis in Caco-2 cell line but it could inhibit the invasion of colon cancer cells through the basement membrane.