Receptor for advanced glycation end-product (RAGE) gene polymorphism 2245G/A is associated with pro-inflammatory,oxidative-glycation markers and sRAGE in diabetic retinopathy

Background

Receptor for advanced glycation end-product (RAGE) gene polymorphism 2245G/A is associated with diabetic retinopathy (DR). However, the mechanism on how it affects the disease development is still unclear.

Aim

This study aims to investigate the relationship between 2245G/A RAGE gene polymorphism and selected pro-inflammatory, oxidative-glycation markers in DR patients.

Methods

A total of 371 unrelated type 2 diabetic patients [200 with retinopathy, 171 without retinopathy (DNR)] and 235 healthy subjects were recruited. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism method followed by DNA sequencing. The nuclear and cytosolic extracts from peripheral blood mononuclear cells were used for nuclear factor kappa B (NF-κB) p65 and superoxide dismutase activity measurement respectively. Plasma was used for glutathione peroxidase activity, advanced oxidation protein product (AOPP), monocyte chemoattractant protein (MCP)-1, pentosidine and soluble RAGE (sRAGE) measurements.

Results

DR patients with 2245GA genotype had significantly elevated levels of activated NF-κB p65, plasma MCP-1, AOPP and pentosidine but lower level of sRAGE when compared to DR patients with wild-type 2245GG.

Conclusion

The RAGE gene polymorphism 2245G/A is associated with pro-inflammatory, oxidative-glycation markers and circulating sRAGE in DR patients. Patients with 2245GA RAGE genotype could aggravate DR possibly via NF-κB mediated inflammatory pathway.     

Higher efficiency of ISSR markers over plastid psbA‐trnH region in resolving taxonomical status of genus Ocimum L.

High level of morphological as well as chemical variability exists within the genus Ocimum, and its taxonomy and phylogenetic relationships are still doubtful. For evaluating interspecific genetic relationships among the Ocimum species, genotyping with intersimple sequence repeat (ISSR) markers and sequence analyses of noncoding psbA‐trnH intergenic region belonging to chloroplast DNA were carried out. Although ISSR markers are highly efficient and reproducible, they have not been used extensively in phylogenetic studies. The use of the plastidial barcode candidate was expected to provide more variable and informative insight into evolutionary rates, and was thus employed as a phylogenetic marker to assess interspecific relationships. This study revealed that the ISSR markers were more efficient than psbA‐trnH sequences in resolving the current status of Ocimum L. genus. Distance‐ and character‐based methodological approaches applied on the molecular data with biparental and maternal inheritance were used for deducing the phylogenetic relationships among Ocimum species. Average polymorphic information content (0.344) and resolving power (6.285) depicted through ISSR markers proved to be efficient in discriminating the studied species of Ocimum. The primers used in this study revealed 99.585% polymorphism across the species demonstrating the polymorphic nature of ISSR markers.     

Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents

The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC–MS analysis.Abbreviations: ABTS, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid), DPPH, 2,2-diphenyl-1-picrylhydrazyl, GAE, gallic acid equivalent, GC–MS, gas chromatography and mass spectrometry     

A short note on oxytocin and stress attenuation

Stress is integral part of life and it initiates appropriate response at times of adversities to promise survival. Stress could be either physiological or psychogenic. Stress is often psychogenic in nature and it induces the release of cortisol from adrenal cortex into circulation by activating Hypo thalamo-pituitary-adrenal axis (HPA). Cortisol thus released mediates the stress response by its catabolic effects to enhance the activity of vital organs during emergency. However, prolonged activation of the HPA axis can lead to physical and mental illness as an outcome of persistent stress. Nature has bestowed the biological system with an array of endogenous mechanisms to buffer stress. Oxytocin, a nano-peptide released by the magno-cellular neurons of hypothalamic paraventricular nucleus (PVN) is an efficient stress buffering neuro-peptide. This hormone mediates many physiological and behavioural functions get released during stress. It attenuates the stress axis initiated by the release of corticotropin releasing hormone (CRH) from the parvocellular neurons of the same hypothalamic nucleus. Oxytocin released by PVN exerts an inhibitory effect on the release of CRH by down-regulating the expression of the gene that transcribes for this hypothalamic hormone. Thus, it inhibits the release of adreno cotico trophic hormone (ACTH) and cortisol, exerting an overall suppressive modulation of the stress axis and attenuates stress.     

Enhanced photocatalytic and electrochemical performance of hydrothermally prepared NiO-doped Co nanocomposites

In this study, we synthesize nanostructured nickel oxide (NiO) and doped cobalt (Co) by combining nickel(II) chloride hexahydrate (NiCl₂.6H₂O) and sodium hydroxide (NaOH) as initial substances. We analyzed the characteristics of the product nanostructures, including their structure, optical properties, and magnetic properties, using various techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet absorption spectroscopy (UV–Vis), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometers (VSM). The NiO nanoparticles doped with Co showed photocatalytic activity in degrading methylene blue (MB) dye in aqueous solutions. We calculated the degradation efficiencies by analyzing the UV–Vis absorption spectra at the dye's absorption wavelength of 664 nm. It was observed that the NiO-doped Co nanoparticles facilitated enhanced recombination and migration of active elements, which led to more effective degradation of organic dyes during photocatalysis. We also assessed the electrochemical properties of the materials using cyclic voltammetry (CV) and impedance spectroscopy in a 1 mol% NaOH solution. The NiO-modified electrode exhibited poor voltammogram performance due to insufficient contact between nanoparticles and the electrolyte solution. In contrast, the uncapped NiO's oxidation and reduction cyclic voltammograms displayed redox peaks at 0.36 and 0.30 V, respectively.     

Measurement of oxygen consumption in mouse aortic endothelial cells using a microparticulate oximetry probe

The purpose of this study was to determine the rate of oxygen consumption in mouse aortic endothelial cells (MAECs) and to determine the effect of a variety of inhibitors and stimulators of oxygen consumption measured by electron paramagnetic resonance (EPR) spectroscopy utilizing a new particulate oximetry probe. We have previously demonstrated that the octa-n-butoxy derivative of naphthalocyanine neutral radical (LiNc-BuO) enables accurate, precise, and reproducible measurements of pO(2) in cellular suspensions. In the current study, we carried out measurements to provide an accurate determination of pO(2) in small volume with less number of cells (20,000 cells) that has not been possible with other techniques. To establish the reliability of this method, agents such as menadione, lipopolysaccharide (LPS), potassium cyanide, rotenone, and diphenyleneiodonium chloride (DPI) were used to modulate the oxygen consumption rate in the cells. We observed an increase in oxygen consumption by the cells upon treatment with menadione and LPS, whereas treatment with cyanide, rotenone, and DPI inhibited oxygen consumption. This study clearly demonstrated the utilization of EPR spectrometry with LiNc-BuO probe for determination of oxygen concentration in cultured cells.     

Application of a trityl-based radical probe for measuring superoxide

The use of triarylmethyl (trityl) free radical, TAM OX063, for detection of superoxide in aqueous solutions by electron paramagnetic resonance (EPR) spectroscopy was investigated. TAM is paramagnetic (EPR active), highly soluble in water and exhibits a single sharp EPR peak in aqueous media. It is also highly stable in presence of many oxidoreductants such as ascorbate and glutathione that are present in the biological systems. TAM reacts with superoxide with an apparent second order rate constant of 3.1 × 10³ M⁻¹ s⁻¹. The specific reactivity of TAM with superoxide, which leads to loss of EPR signal, was utilized to detect the generation of superoxide in various chemical (light/riboflavin/electron/donor), enzymatic (xanthine/xanthine oxidase), and cellular (stimulated neutrophils) model systems. The changes in the EPR line-width, induced by molecular oxygen, were utilized in the simultaneous determination of consumption of oxygen in the model systems. The effects of flux of superoxide and concentration of TAM on the efficiency of detection of superoxide were studied. The use of TAM for detection of superoxide offers unique advantages namely, (i) the utilization of very low concentration of the probe, (ii) its stability to bioreduction, and (iii) its use in the simultaneous determination of concentrations of superoxide and oxygen.     

In vivo measurement and mapping of skin redox stress induced by ultraviolet light exposure

Exposure of skin to UV light presents a potent oxidative stress and this could alter the skin redox state. In this context, we evaluated the ability of electron paramagnetic resonance (EPR) imaging to provide noninvasive in vivo mapping of the redox status of the skin of living rats. The redox status was measured using a topically applied nitroxyl spin probe, (15)N-PDT. The nitroxyl intensity profile obtained across the skin layers showed that the concentration of the probe was higher in the epidermis and lower in the dermis and hypodermis. Skin permeability and reduction metabolism were evaluated in the skin exposed to UVB (312 nm) radiation. Exposure of skin to UVB decreased the overall reduction rate constant of the nitroxyl probe to 25 +/- 6% of the value obtained in the untreated skin. EPR imaging data showed that after the UVB treatment, the reduction rate constant decreased to 41 +/- 1% in epidermis, 28 +/- 1% in dermis, and 21 +/- 8% in hypodermis layers. The data suggested that UVB decreased the overall reducing capability of the skin with a larger decrease in the dermis and hypodermis. In summary, in vivo EPR imaging measurements showed significant alterations in the redox state of the skin exposed to UV light.     

Re-oxygenation causes hypoxic tumor regression through restoration of p53 wild-type conformation and post-translational modifications

Hypoxic tumors are resistant to conventional therapies through indirect mechanisms such as the selection of resistant phenotype under chronic hypoxia. Hyperbaric oxygen (HBO) therapy has been shown to increase oxygen level and induce apoptosis in hypoxic tumor. However, it could produce significant adverse effects including oxygen toxic seizures and severe radiation tissue injury due to high pressure. We have shown that repeated oxygenation at 30% O₂ (1 atmospheres absolute) results in significant regression of MCF-7 tumor xenografts without any adverse effect. In MCF-7 cells, re-oxygenation showed an eightfold increase in cellular apoptosis. Both in hypoxic tumor and in hypoxic cells, that exclusively favor p53 to exist in mutant conformation, re-oxygenation restores p53 wild-type conformation. The oxygen-mediated rescue of mutant p53 followed by its trans-activation is responsible for the induction of p53-downstream apoptotic, cell-cycle arrest and DNA-repair genes. Further, p53 trans-activation may thus be due to its post-translational modifications as a result of re-oxygenation. We have thus concluded that oxygen therapy without pressure, as opposed to HBO therapy, may be ideal for hypoxic tumor regression, which functions through oxygen-mediated rescue of mutant p53 followed by induction of apoptosis.     

Highly selective fluorescent sensing of fenitrothion using per-6-amino-β-cyclodextrin:Eu(III) complex

A unique, efficient, highly sensitive and selective fluorescent chemosensor for fenitrothion has been reported for the first time using per-6-amino-β-cyclodextrin:Eu(III) complex. Among the various pesticides, the sensitivity response is found to be in the order, fenitrothion>quinalphos>methylparathion>parathion>methylparaoxon>paraoxon>fenchlorphos>profenofos>malathion. A detection limit as low as 1 × 10(-12)M for fenitrothion sensing is realized with a 2.4% relative standard deviation (RSD) of three consecutive runs. The per-6-amino-β-cyclodextrin:Eu(III):pesticide complexes and their sensing mechanism are evidenced from emission, NMR, FT-IR, binding constant measurement, Job's plot, ICD spectra, ESI-MS, lifetime measurements and molecular modeling studies. The proposed sensing is a consequence of Absorption Energy Transfer Emission (AETE) process as a result of better encapsulation of fenitrothion inside the cavity of per-6-amino-β-cyclodextrin:Eu(III) complex. The remarkable sensitivity and selectivity of fenitrothion compared to other OPs, is attributed to a more deeper binding and tighter fit of fenitrothion inside the CD cavity, which is evident from binding constant values and molecular modeling studies. This tighter fit ensures the replacement of two coordinating water molecules on Eu(III) ion, which may have contributed to the more selective sensing of fenitrothion.