Deglycation activity of the Escherichia coli glycolytic enzyme phosphoglucose isomerase.

Glycation is a spontaneous chemical reaction, which affects the structure and function of proteins under normal physiological conditions. Therefore, organisms have evolved diverse mechanisms to combat glycation. In this study, we show that the Escherichia coli glycolytic enzyme phosphoglucose isomerase (Pgi) exhibits deglycation activity. We found that E. coli Pgi catalyzes the breakdown of glucose 6-phosphate (G6P)-derived Amadori products (APs) in chicken lysozyme. The affinity of Pgi to the glycated lysozyme (Km, 1.1 mM) was ten times lower than the affinity to its native substrate, fructose 6-phosphate (Km, 0.1 mM). However, the high kinetic constants of the enzyme with the glycated lysozyme (kcat, 396 s-1 and kcat/Km, 3.6 × 105 M-1 s-1) indicated that the Pgi amadoriase activity may have physiological implications. Indeed, when using total E. coli protein (20 mg/mL) as a substrate in the deglycation reaction, we observed a release of G6P from the bacterial protein at a Pgi specific activity of 33 µmol/min/mg. Further, we detected 11.4 % lower APs concentration in protein extracts from Pgi-proficient vs. deficient cells (p = 0.0006) under conditions where the G6P concentration in Pgi-proficient cells was four times higher than in Pgi-deficient cells (p = 0.0001). Altogether, these data point to physiological relevance of the Pgi deglycation activity.

Neurotensin(8-13) analogs as dual NTS1 and NTS2 receptor ligands with enhanced effects on a mouse model of Parkinson's disease.

The modulatory interactions between neurotensin (NT) and the dopaminergic neurotransmitter system in the brain suggest that NT may be associated with the progression of Parkinson's disease (PD). NT exerts its neurophysiological effects by interactions with the human NT receptors type 1 (hNTS1) and 2 (hNTS2). Therefore, both receptor subtypes are promising targets for the development of novel NT-based analogs for the treatment of PD. In this study, we used a virtually guided molecular modeling approach to predict the activity of NT(8-13) analogs by investigating the docking models of ligands designed for binding to the human NTS1 and NTS2 receptors. The importance of the residues at positions 8 and/or 9 for hNTS1 and hNTS2 receptor binding affinity was experimentally confirmed by radioligand binding assays. Further in vitro ADME profiling and in vivo studies revealed that, compared to the parent peptide NT(8-13), compound 10 exhibited improved stability and BBB permeability combined with a significant enhancement of the motor function and memory in a mouse model of PD. The herein reported NTS1/NTS2 dual-specific NT(8-13) analogs represent an attractive tool for the development of therapeutic strategies against PD and potentially other CNS disorders.

Surface Photovoltage Study of Metal Halide Perovskites Deposited Directly on Crystalline Silicon.

Perovskite (PVK) films deposited directly on n-type crystalline Si substrates were investigated by two operating modes of the surface photovoltage (SPV) method: (i) the metal-insulator-semiconductor (MIS) mode and (ii) the Kelvin probe force microscopy (KPFM). By scanning from 900 to 600 nm in the MIS mode, we consecutively studied the relatively fast processes of carrier generation, transport, and recombination first in Si, then on both sides of the PVK/Si interface, and finally in the PVK layer and its surface. The PVK optical absorption edge was observed in the range of 1.61-1.65 eV in good agreement with the band gap of 1.63 eV found from photoluminescence spectra. Both SPV methods evidenced an upward energy band bending at the PVK/n-Si interface generating positive SPV. Drift-diffusion modeling allowed us to analyze the shape of the wavelength dependence of the SPV. It was also observed that the intense illumination in the KPFM measurements induces slow SPV transients which were explained by the creation and migration of negative ions and their trapping at the PVK surface. Finally, aging effects were studied by measuring again SPV spectra after one-year storage in air, and an increase in the concentration of shallow defect states at the PVK/n-Si interface was found.

New Galantamine Derivatives with Inhibitory Effect on Acetylcholinesterase Activity.

BACKGROUND: Inhibitors of acetylcholinesterase (AChE) are used to treat many disorders, among which are neurodegenerative upsets, like Alzheimer's disease (AD). One of the limited licensed AChE inhibitors (AChEIs) used as drugs is the natural compound galantamine (Gal). OBJECTIVE: As Gal is a toxic compound, here we expose data about its four derivatives in hybrid peptide-norgalantamine molecules, which have shown 100 times lower toxicity. METHODS: Four newly synthesized galantamine derivatives have been involved in docking analysis made by Molegro Virtual Docker. Biological assessments were performed on ICR male mice. The change in short and long-term memory performance was evaluated by passive avoidance test. AChE activity and levels of main oxidative stress parameters: lipid peroxidation, total glutathione (GSH), enzyme activities of catalase (CAT), superoxide dismutase, and glutathione peroxidase were measured in brain homogenates. RESULTS: Our experimental data revealed that the new hybrid molecules did not impair memory performance in healthy mice. Two of the compounds demonstrated better than Gal AChE inhibitory activity in the brain. None of them changed the level of lipid peroxidation products, one of the compounds increased GSH levels, and all of them increased CAT enzyme activity. CONCLUSION: The new galantamine-peptide hybrids demonstrated a potential for inhibition of AChE and antioxidant activity and deserve further attention.

Real-World Effectiveness and Safety of Insulin Glargine 300 U/mL in Patients with T2D Uncontrolled on NPH or Premixed Insulins as Part of Routine Clinical Practice in Bulgaria: ToUPGRADE Study.

INTRODUCTION: The aim of this study is to demonstrate the real-life effectiveness and safety of insulin glargine 300 U/mL (Gla-300) in patients with type 2 diabetes (T2D) previously uncontrolled on NPH ± prandial insulin or premixed insulins in routine clinical practice in Bulgaria. METHODS: This was a 24-week prospective, observational study performed in 40 inpatient and outpatient sites across the country. RESULTS: A total of 286 patients were included in the study. The mean age (± SD) was 61.2 ± 10.0 years with duration of diabetes of 11.64 ± 7.5 years and body mass index (BMI) of 32.1 ± 5.7 kg/m2. HbA1c before Gla-300 initiation was 9.8 ± 1.0%, and fasting plasma glucose (FPG) was 13.1 ± 3.4 mmol/L. HbA1c and FPG change from baseline to week 24 was - 1.86% (p < 0.001) and - 4.8 mmol/L (p < 0.001), respectively. The proportion of patients reaching their individualized HbA1c at week 24 was 39.1% (95% CI 33.3-45.1%), while the proportion of patients reaching their individualized HbA1c target without confirmed and/or severe hypoglycaemia was 34.8% (95% CI 29.2-40.7%). At study end, 19.0% (95% CI 14.6-24.1%) achieved HbA1c < 7%. Body weight decreased from 88.3 to 87.0 kg from baseline to week 24 with mean change of - 1.3 kg (p < 0.001). The incidence and event rates of anytime confirmed (≤ 3.9 mmol/L) and/or severe hypoglycaemia were low: 7.7% and 0.42 events per patient-year, respectively. The overall Insulin Treatment Satisfaction Questionnaire (ITSQ) score increased from 53.2 to 78.2 from baseline to week 24 and the difference of 25.1 ± 21.5 points was significant (p < 0.001). CONCLUSIONS: In real-life settings, Gla-300 significantly improved glycaemic control and insulin treatment satisfaction in people with T2D who were inadequately controlled with NPH ± prandial insulin or premixed insulin analogues. Improvement of glycaemic control was associated with a very low risk of hypoglycaemia and with significant weight loss irrespective of the previous insulin regimen.

Neurotensins and their therapeutic potential: research field study.

The natural tridecapeptide neurotensin has been emerged as a promising therapeutic scaffold for the treatment of neurological diseases and cancer. In this work, we aimed to identify the top 100 most cited original research papers as well as recent key studies related to neurotensins. The Web of Science Core Collection database was searched and the retrieved research articles were analyzed by using the VOSviewer software. The most cited original articles were published between 1973 and 2013. The top-cited article was by Carraway and Leeman reporting the discovery of neurotensin in 1973. The highly cited terms were associated with hypotension and angiotensin-converting-enzyme. The conducted analysis reveals the therapeutic potentials of neurotensin, and further impactful research toward its clinical development is warrantied.