Inhibition of Methicillin-resistant Staphylococcus aureus-induced cytokines mRNA production in human bone marrow derived mesenchymal stem cells by 1,25-dihydroxyvitamin D3

Background Methicillin-resistant Staphylococcus aureus (MRSA) is the predominant cause of bone infection. Toll like receptors (TLRs) are an important segments of host response to infection and are expressed by a variety of cells including human mesenchymal stem cells (hMSCs). The active form of Vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has potent immunoregulatory properties, but the mechanism remains poorly understood. The genomic action of 1,25(OH)2D3 is mediated by vitamin D receptor (VDR), hormone-regulated transcription factor. VDR interacts with co-activators and co-repressors are associated with chromatin histone modifications and transcriptional regulation. The aim of our study is to explore MRSA-induced TLRs-mediated pro-inflammatory cytokines expression in hMSCs. Further, we hypothesized that 1,25(OH)2D3 inhibits MRSA-induced cytokines synthesis in hMSCs via inhibition of NF-кB transcription factor. Finally, we explored the regulatory role of 1,25(OH)2D3 in MRSA-mediated global epigenetic histone H3 mark, such as, trimethylated histone H3 lysine 9 (H3K9me3), which is linked to gene silencing. Results Quantitative PCR data revealed that MRSA-infection predominantly induced expression of TLRs 1, 2, 6, NR4A2, and inflammatory cytokines IL-8, IL-6, TNFα in hMSCs. MRSA-mediated TLR ligands reduced osteoblast differentiation and increased hMSCs proliferation, indicating the disrupted multipotency function of hMSCs. Pretreatment of 1,25(OH)2D3 followed by MRSA co-culture inhibited nuclear translocation of NF-кB-p65, reduced expression of NR4A2 and pro-inflammatory cytokines IL-8, IL-6, and TNFα in hMSCs. Further, NF-κB-p65, VDR, and NR4A2 were present in the same nuclear protein complex, indicating that VDR is an active part of the nuclear protein complexes for transcriptional regulation. Finally, 1,25(OH)2D3 activated VDR, restores the global level of H3K9me3, to repress MRSA-stimulated inflammatory cytokine IL-8 expression. Pretreatment of 5-dAZA, DNA methylatransferases (Dnmts) inhibitor, dramatically re-expresses 1,25(OH)2D3-MRSA-mediated silenced IL-8 gene. Conclusions This data indicates that TLR 1, 2, and 6 can be used as markers for localized S. aureus bone infection. 1,25(OH)2D3-VDR may exhibits its anti-inflammatory properties in MRSA-stimulated infection by inhibiting nuclear translocation of NF-kB-p65 and transcripts of IL-8, IL-6, TNFα, and NR4A2 in hMSCs. Finally, 1,25(OH)2D3-activated VDR, acting as an epigenetic regulator, inhibits synthesis of cytokines in MRSA-stimulated infection by restoring the global level of H3K9me3, a histone H3 mark for gene silencing

The Role of Sphingosine-1-Phosphate and Ceramide-1-Phosphate in Inflammation and Cancer

Inflammation is part of our body’s response to tissue injury and pathogens. It helps to recruit various immune cells to the site of inflammation and activates the production of mediators to mobilize systemic protective processes. However, chronic inflammation can increase the risk of diseases like cancer. Apart from cytokines and chemokines, lipid mediators, particularly sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P), contribute to inflammation and cancer. S1P is an important player in inflammation-associated colon cancer progression. On the other hand, C1P has been recognized to be involved in cancer cell growth, migration, survival, and inflammation. However, whether C1P is involved in inflammation-associated cancer is not yet established. In contrast, few studies have also suggested that S1P and C1P are involved in anti-inflammatory pathways regulated in certain cell types. Ceramide is the substrate for ceramide kinase (CERK) to yield C1P, and sphingosine is phosphorylated to S1P by sphingosine kinases (SphKs). Biological functions of sphingolipid metabolites have been studied extensively. Ceramide is associated with cell growth inhibition and enhancement of apoptosis while S1P and C1P are associated with enhancement of cell growth and survival. Altogether, S1P and C1P are important regulators of ceramide level and cell fate. This review focuses on S1P and C1P involvement in inflammation and cancer with emphasis on recent progress in the field

Effect of Hydrocarbon Chain and Amide Linkage on the Interfacial and Self-Assembly Properties of Nicotinic Acid Amphiphiles

Three nicotinic acid amphiphiles, sodium 6-octylnicotinate (SONA), sodium 6-decylnicotinate (SDNA), and sodium 6-decylnicotinic glycinate (SDNAG), have been synthesized, and the effect of hydrocarbon chain length as well as amide linkage on the self-assembly properties in aqueous solutions have been investigated using a number of techniques, including tensiometry, fluorometry, FT-IR spectroscopy, ¹H NMR spectroscopy, UV–vis spectroscopy, dynamic light scattering, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Tensiometry measurements reveal the presence of two critical aggregation concentrations (CACs) for simple aliphatic chain amphiphiles, whereas a single CAC was obtained when glycine was introduced in the headgroup. Gel permeation chromatography studies indicate the presence of closed bilayer aggregates for all of the amphiphiles in aqueous solutions. XRD spectra indicate the presence of a non-interdigited bilayer structure. The presence of bilayer vesicles was confirmed by TEM measurements. Permeability of the bilayer membranes of the vesicles were investigated using the model water-soluble dye methylene blue. The vesicles obtained with nicotinic acid amphiphiles could be used as versatile carriers suitable for both hydrophobic and hydrophilic molecules

Spontaneous Formation of Vesicles by Sodium 2‑Dodecylnicotinate in Water

The surface activity and aggregation behavior of a synthesized nicotinic acid based anionic surfactant, sodium 2-dodecylnicotinate, were studied in aqueous solution. The self-assembly formation was investigated by use of a number of techniques, including surface tension and conductivity measurements, fluorescence spectroscopy, dynamic light scattering measurement, gel permeation chromatography, and microscopy. The amphiphile exhibits two breaks in the surface tension vs concentration plot, indicating stepwise aggregate formation and thus producing two values of the aggregation concentration. Stepwise aggregation of the amphiphile was further confirmed by steady-state fluorescence spectroscopy using pyrene as a probe molecule, and also the micropolarity of the aggregates was determined. The rigidity of the microenvironment was estimated by determining steady-state fluorescence anisotropy using 1,6-diphenyl-1,3,5-hexatriene as a fluorescence probe molecule. The average hydrodynamic radius and size distribution of the aggregate suggest formation of larger aggregates in aqueous solution. The formation of vesicles in water was established by conductivity measurement and a dye entrapment experiment. The entrapment of a small solute and the release capability have also been examined to demonstrate these bilayers form enclosed vesicles. Transmission electron micrographs revealed the existence of closed vesicles and closed tubules in aqueous solution. Therefore, for the first time, it has been observed that this simple single-chain nicotinic acid based amphiphile spontaneously assembles to vesicles in aqueous solution

Effect of pH and Oxygen Atom of the Hydrophobic Chain on the Self-Assembly Property and Morphology of the Pyridyl Boronic Acid Based Amphiphiles

The surface activity and aggregation behavior of two synthesized boronic acid based anionic surfactants, sodium salt of 2-dodecyl pyridine-5-boronic acid (SDDPB) and sodium salt of 2-oxydodecyl pyridine-5-boronic acid (SODDPB), were studied in buffer solution at pH 9 and 13 containing carbohydrates. The self-assembly formation was investigated by use of a number of techniques including surface tension, conductivity, fluorescence spectroscopy, dynamic light scattering, X-ray diffraction, and transmission electron microscopy (TEM). Both of the amphiphiles exhibit a single break in the surface tension vs log­(concentration) plots, indicating existence of one critical aggregation concentration. Steady state fluorescence spectroscopy was used to determine the polarity indexes using pyrene and the rigidity of the microenvironments of the aggregates using 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescence probe molecules. The p<i>K</i>_a’s of both amphiphiles were determined in buffer solutions of different pH’s. XRD studies were performed to shed light on the morphology of the self-assemblies. TEM micrographs revealed the existence of vesicles for both the amphiphiles in buffer solution of pH 9, but at pH 13, TEM pictures indicate the existence of closed vesicles in SDDPB solution and at concentrated solution the vesicles are fused to form sponge-like micelles. After aging the vesicular solution of pH 13 of SDDPB, the closed vesicles are destroyed. In contrast, for SODDPB at pH 13, TEM pictures suggest the existence of spherical and complex micelles in solution which were further transformed into crystal-like structure upon aging. The average hydrodynamic radii were determined by dynamic light scattering measurement. Therefore, for the first time, we have successfully synthesized two new surfactants containing pyridyl-boronic acid as a headgroup which shows remarkable tuning of morphology in two different pH’s and in the presence of two different carbohydrates

Effect of Hydrocarbon Chain and Amide Linkage on the Interfacial and Self-Assembly Properties of Nicotinic Acid Amphiphiles

Three nicotinic acid amphiphiles, sodium 6-octylnicotinate (SONA), sodium 6-decylnicotinate (SDNA), and sodium 6-decylnicotinic glycinate (SDNAG), have been synthesized, and the effect of hydrocarbon chain length as well as amide linkage on the self-assembly properties in aqueous solutions have been investigated using a number of techniques, including tensiometry, fluorometry, FT-IR spectroscopy, ¹H NMR spectroscopy, UV–vis spectroscopy, dynamic light scattering, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Tensiometry measurements reveal the presence of two critical aggregation concentrations (CACs) for simple aliphatic chain amphiphiles, whereas a single CAC was obtained when glycine was introduced in the headgroup. Gel permeation chromatography studies indicate the presence of closed bilayer aggregates for all of the amphiphiles in aqueous solutions. XRD spectra indicate the presence of a non-interdigited bilayer structure. The presence of bilayer vesicles was confirmed by TEM measurements. Permeability of the bilayer membranes of the vesicles were investigated using the model water-soluble dye methylene blue. The vesicles obtained with nicotinic acid amphiphiles could be used as versatile carriers suitable for both hydrophobic and hydrophilic molecules

Knowledge and Practice of Impression Techniques for Complete Edentulous Patients

&nbsp;Impression making for completely edentulous patients is one of the critical factors in determining the success or failure of complete denture therapy. Precise reproduction of an edentulous foundation is essential for removable prosthesis retention, stability, and support. Evidence indicates that materials and methods differ in the way impressions are produced for complete dentures. An online survey involving 100 individuals by random sampling method which included Prosthodontics Postgraduates, Undergraduates, and General Practitioners from different locations in India after getting proper consent from the participants about various impression techniques performed for completely edentulous patients. The results were collected and then analyzed through SPSS software. Descriptive statistical analysis was carried out and the chi-square test was used and the p-value was calculated. This survey analysis has provided a clear view about the impression techniques and practices followed by Dental Practitioners in the process of taking an impression for completely edentulous patients which included theory followed during impression making, primary impression-tray, border molding material, primary and final impression material, border molding material, correction material, use of the custom tray, tissue stop, spacer, posterior palatal seal, flabby tissue and neutral zone for the taking of better impressions for completely edentulous patients. The present study about the knowledge and practice of impression techniques followed by Indian Dental Practitioners has provided a clear view about the current procedures undertaken by them and also provides a better view to improving certain procedures and techniques for the betterment of patients in futur

Gel-Emulsion Properties of Nontoxic Nicotinic Acid-Derived Glucose Sensor

Amide linkage containing two nicotinic acid amphiphiles have been investigated for their gel-emulsion and glucose sensing properties. In emulsions, the synthesized materials were used as stabilizers in water medium, whereas organic solvents and/or mineral oils as dispersed phase and water acts as a continuous phase. The gel-emulsions were prepared at room temperature by stirring or shaking, and no heating–cooling arrangement or addition of any other co-solvents or active agents are mandatory. Rheological investigation of these amphiphiles showed mechanical stability of gel-emulsions and its viscoelasticity. Optical images confirmed the existence of network structures in gel-emulsion phase for both amphiphiles. FE-SEM measurement suggests the morphology depends on the solvent:water composition. An XRD study proposed that the arrangements of the amphiphiles in the emulsion state are different. The gel-emulsions formed by the studied amphiphiles are able to entrap and release biomolecules, anticancer drug molecules, and hazards chemicals. These gelator molecules are very sensitive to detect glucose molecules in aqueous solution. The subchronic toxicity of these synthesized molecules has been evaluated as nontoxic on the hematological and biochemical parameters of male Swiss albino mice