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Journal of Ayurveda and Integrative... 2023Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to...
BACKGROUND
Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to increase in the utilization of herbal medicines. Polyherbal emulgel resolves the bioavailability issue associated with hydrophobic drugs and can be used effectively in the treatment of RA.
OBJECTIVES
The present study aimed at the formulation of polyherbal emulgel, and evaluation of in vitro anti-inflammatory activity and in vivo antiarthritic activity.
METHODS
Seven emulgels F-1 to F-7 were optimally formulated. In vitro anti-inflammatory activity was determined using protein denaturation method employing Diclofenac sodium as the standard. In antiarthritic study Complete Freund's Adjuvant (CFA) model was used. The various parameters were assessed, like paw volume, body weight, hematological parameters, antioxidant parameters, Rheumatic factor (RF), and histopathological study of ankle joint.
RESULTS
F-4 and F-7 were found to be optimized formulations as compared to other formulations. The in vitro anti-inflammatory activity was found to be highest in F-4 with IC 7.74 and F-7 with IC 8.87 in comparison with Diclofenac sodium having IC 57.0. Both formulations F-7 and F-4 showed a significant reduction in paw volume and normalization of body weights. The formulation F-7 even showed more potent antiarthritic activity than F-4 by decreasing white blood cells (WBC), lymphocytes, increasing packed cell volume (PCV), neutrophils, superoxide dismutase (SOD), catalase and decreasing malondialdehyde (MDA) levels in serum. This was further confirmed by histopathological study.
CONCLUSION
As an anti-inflammatory agent, this newly developed emulgel was found to possess more therapeutic efficacy than commercially available diclofenac sodium.
PubMed: 38016365
DOI: 10.1016/j.jaim.2023.100828 -
Biophysical Journal Mar 2021Based on a model of protein denaturation rate limited by an entropy-related barrier, we derive a simple formula for virus inactivation time as a function of temperature....
Based on a model of protein denaturation rate limited by an entropy-related barrier, we derive a simple formula for virus inactivation time as a function of temperature. Loss of protein structure is described by two reaction coordinates: conformational disorder of the polymer and wetting by the solvent. These establish a competition between conformational entropy and hydrophobic interaction favoring random coil or globular states, respectively. Based on the Landau theory of phase transition, the resulting free energy barrier is found to decrease linearly with the temperature difference T - T, and the inactivation rate should scale as U to the power of T - T. This form recalls an accepted model of thermal damage to cells in hyperthermia. For SARS-CoV-2 the value of U in Celsius units is found to be 1.32. Although the fitting of the model to measured data is practically indistinguishable from Arrhenius law with an activation energy, the entropy barrier mechanism is more suitable and could explain the pronounced sensitivity of SARS-CoV-2 to thermal damage. Accordingly, we predict the efficacy of mild fever over a period of ∼24 h in inactivating the virus.
Topics: COVID-19; Fever; Humans; SARS-CoV-2; Temperature; Virus Inactivation
PubMed: 33253633
DOI: 10.1016/j.bpj.2020.11.2259 -
Frontiers in Molecular Biosciences 2022Cryo-sample preparation is a vital step in the process of obtaining high-resolution structures of macromolecules by using the single-particle cryo-electron microscopy... (Review)
Review
Cryo-sample preparation is a vital step in the process of obtaining high-resolution structures of macromolecules by using the single-particle cryo-electron microscopy (cryo-EM) method; however, cryo-sample preparation is commonly hampered by high uncertainty and low reproducibility. Specifically, the existence of air-water interfaces during the sample vitrification process could cause protein denaturation and aggregation, complex disassembly, adoption of preferred orientations, and other serious problems affecting the protein particles, thereby making it challenging to pursue high-resolution 3D reconstruction. Therefore, sample preparation has emerged as a critical research topic, and several new methods for application at various preparation stages have been proposed to overcome the aforementioned hurdles. Here, we summarize the methods developed for enhancing the quality of cryo-samples at distinct stages of sample preparation, and we offer insights for developing future strategies based on diverse viewpoints. We anticipate that cryo-sample preparation will no longer be a limiting step in the single-particle cryo-EM field as increasing numbers of methods are developed in the near future, which will ultimately benefit the entire research community.
PubMed: 35813814
DOI: 10.3389/fmolb.2022.892459 -
Journal of Immunology Research 2019A protein undergoes many types of posttranslation modification. Citrullination is one of these modifications, where an arginine amino acid is converted to a citrulline... (Meta-Analysis)
Meta-Analysis Review
A protein undergoes many types of posttranslation modification. Citrullination is one of these modifications, where an arginine amino acid is converted to a citrulline amino acid. This process depends on catalytic enzymes such as peptidylarginine deiminase enzymes (PADs). This modification leads to a charge shift, which affects the protein structure, protein-protein interactions, and hydrogen bond formation, and it may cause protein denaturation. The irreversible citrullination reaction is not limited to a specific protein, cell, or tissue. It can target a wide range of proteins in the cell membrane, cytoplasm, nucleus, and mitochondria. Citrullination is a normal reaction during cell death. Apoptosis is normally accompanied with a clearance process via scavenger cells. A defect in the clearance system either in terms of efficiency or capacity may occur due to massive cell death, which may result in the accumulation and leakage of PAD enzymes and the citrullinated peptide from the necrotized cell which could be recognized by the immune system, where the immunological tolerance will be avoided and the autoimmune disorders will be subsequently triggered. The induction of autoimmune responses, autoantibody production, and cytokines involved in the major autoimmune diseases will be discussed.
Topics: Autoimmune Diseases; Autoimmunity; Biomarkers; Citrullination; Citrulline; Disease Susceptibility; Genetic Predisposition to Disease; Humans; Protein-Arginine Deiminases; Risk Factors
PubMed: 31886309
DOI: 10.1155/2019/7592851 -
Journal of the American Chemical Society Apr 2022Although cold denaturation is a fundamental phenomenon common to all proteins, it can only be observed in a handful of cases where it occurs at temperatures above the...
Although cold denaturation is a fundamental phenomenon common to all proteins, it can only be observed in a handful of cases where it occurs at temperatures above the freezing point of water. Understanding the mechanisms that determine cold denaturation and the rules that permit its observation is an important challenge. A way to approach them is to be able to induce cold denaturation in an otherwise stable protein by means of mutations. Here, we studied CyaY, a relatively stable bacterial protein with no detectable cold denaturation and a high melting temperature of 54 °C. We have characterized for years the yeast orthologue of CyaY, Yfh1, a protein that undergoes cold and heat denaturation at 5 and 35 °C, respectively. We demonstrate that, by transferring to CyaY the lessons learnt from Yfh1, we can induce cold denaturation by introducing a restricted number of carefully designed mutations aimed at destabilizing the overall fold and inducing electrostatic frustration. We used molecular dynamics simulations to rationalize our findings and demonstrate the individual effects observed experimentally with the various mutants. Our results constitute the first example of rationally designed cold denaturation and demonstrate the importance of electrostatic frustration on the mechanism of cold denaturation.
Topics: Cold Temperature; Hot Temperature; Molecular Dynamics Simulation; Protein Denaturation; Proteins; Thermodynamics
PubMed: 35427450
DOI: 10.1021/jacs.1c13355 -
Cold Spring Harbor Perspectives in... Apr 2020The functional health of the proteome is determined by properties of the proteostasis network (PN) that regulates protein synthesis, folding, macromolecular assembly,... (Review)
Review
The functional health of the proteome is determined by properties of the proteostasis network (PN) that regulates protein synthesis, folding, macromolecular assembly, translocation, and degradation. In eukaryotes, the PN also integrates protein biogenesis across compartments within the cell and between tissues of metazoans for organismal health and longevity. Additionally, in metazoans, proteome stability and the functional health of proteins is optimized for development and yet declines throughout aging, accelerating the risk for misfolding, aggregation, and cellular dysfunction. Here, I describe the cell-nonautonomous regulation of organismal PN by tissue communication and cell stress-response pathways. These systems are robust from development through reproductive maturity and are genetically programmed to decline abruptly in early adulthood by repression of the heat shock response and other cell-protective stress responses, thus compromising the ability of cells and tissues to properly buffer against the cumulative stress of protein damage during aging. While the failure of multiple protein quality control processes during aging challenges cellular function and tissue health, genetic studies, and the identification of small-molecule proteostasis regulators suggests strategies that can be employed to reset the PN with potential benefit on cellular health and organismal longevity.
Topics: Aging; Animals; Caenorhabditis elegans; Fibroblasts; Gene Expression Regulation; Heat Shock Transcription Factors; Heat-Shock Proteins; Heat-Shock Response; Humans; Longevity; Protein Denaturation; Protein Folding; Proteins; Proteome; Proteostasis; Quality Control; Risk; Signal Transduction; Stress, Physiological
PubMed: 30962274
DOI: 10.1101/cshperspect.a034074 -
Biomolecules Jan 2021The bacterial flagellum and the related virulence-associated injectisome system of pathogenic bacteria utilize a type III secretion system (T3SS) to export substrate... (Review)
Review
The bacterial flagellum and the related virulence-associated injectisome system of pathogenic bacteria utilize a type III secretion system (T3SS) to export substrate proteins across the inner membrane in a proton motive force-dependent manner. The T3SS is composed of an export gate (FliPQR/FlhA/FlhB) located in the flagellar basal body and an associated soluble ATPase complex in the cytoplasm (FliHIJ). Here, we summarise recent insights into the structure, assembly and protein secretion mechanisms of the T3SS with a focus on energy transduction and protein transport across the cytoplasmic membrane.
Topics: Adenosine Triphosphatases; Bacterial Proteins; Cell Membrane; Cytoplasm; Flagella; Gram-Negative Bacteria; Hydrolysis; Membrane Proteins; Protein Denaturation; Protein Transport; Substrate Specificity; Type III Secretion Systems
PubMed: 33572887
DOI: 10.3390/biom11020186 -
Scientific Reports Nov 2023Thermal shift assay (TSA) with altered temperature has been the most widely used method for monitoring protein stability for drug research. However, there is a pressing...
Thermal shift assay (TSA) with altered temperature has been the most widely used method for monitoring protein stability for drug research. However, there is a pressing need for isothermal techniques as alternatives. This urgent demand arises from the limitations of TSA, which can sometimes provide misleading ranking of protein stability and fail to accurately reflect protein stability under physiological conditions. Although differential scanning fluorimetry has significantly improved throughput in comparison to differential scanning calorimetry and differential static light scattering throughput, all these methods exhibit moderate sensitivity. In contrast, current isothermal chemical denaturation (ICD) techniques may not offer the same throughput capabilities as TSA, but it provides more precise information about protein stability and interactions. Unfortunately, ICD also suffers from limited sensitivity, typically in micromolar range. We have developed a novel method to overcome these challenges, namely throughput and sensitivity. The novel Förster Resonance Energy Transfer (FRET)-Probe as an external probe is highly applicable to isothermal protein stability monitoring but also to conventional TSA. We have investigated ICD for multiple proteins with focus on KRAS with covalent inhibitors and three chemical denaturants performed at nanomolar protein concentration. Data showed corresponding inhibitor-induced stabilization of KRAS to those reported by nucleotide exchange assay.
Topics: Proto-Oncogene Proteins p21(ras); Protein Stability; Fluorometry; Calorimetry, Differential Scanning; Proteins; Protein Denaturation
PubMed: 37973851
DOI: 10.1038/s41598-023-46720-w -
Molecules (Basel, Switzerland) Feb 2021Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and... (Review)
Review
Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately impairing cell viability. Antioxidants scavenge free radicals and reduce oxidative stress, which further helps to prevent cellular damage. Medicinal plants, fruits, and spices are the primary sources of antioxidants from time immemorial. In contrast to plants, microorganisms can be used as a source of antioxidants with the advantage of fast growth under controlled conditions. Further, microbe-based antioxidants are nontoxic, noncarcinogenic, and biodegradable as compared to synthetic antioxidants. The present review aims to summarize the current state of the research on the antioxidant activity of microorganisms including actinomycetes, bacteria, fungi, protozoa, microalgae, and yeast, which produce a variety of antioxidant compounds, i.e., carotenoids, polyphenols, vitamins, and sterol, etc. Special emphasis is given to the mechanisms and signaling pathways followed by antioxidants to scavenge Reactive Oxygen Species (ROS), especially for those antioxidant compounds that have been scarcely investigated so far.
Topics: Antioxidants; Bacteria; Fungi; Microalgae; Molecular Structure
PubMed: 33672774
DOI: 10.3390/molecules26041142 -
Analytical Chemistry Oct 2021The loss of native structure is common in proteins. Among others, aggregation is one structural modification of particular importance as it is a major concern for the...
The loss of native structure is common in proteins. Among others, aggregation is one structural modification of particular importance as it is a major concern for the efficiency and safety of biotherapeutic proteins. Yet, recognizing the structural features associated with intermolecular bridging in a high-throughput manner remains a challenge. We combined here the use of protein microarrays spotted at a density of ca 2500 samples per cm and Fourier transform infrared (FTIR) imaging to analyze structural modifications in a set of 85 proteins characterized by widely different secondary structure contents, submitted or not to mild denaturing conditions. Multivariate curve resolution alternating least squares (MCR-ALS) was used to model a new spectral component appearing in the protein set subject to denaturing conditions. In the native protein set, 6 components were found to be sufficient to obtain good modeling of the spectra. Furthermore, their shape allowed them to be assigned to α-helix, β-sheet, and other structures. Their content in each protein was correlated with the known secondary structure, confirming these assignments. In the denatured proteins, a new component was necessary and modeled by MCR-ALS. This new component could be assigned to the intermolecular β-sheet, bridging protein molecules. MCR-ALS, therefore, unveiled a potential spectroscopic marker of protein aggregation and allowed a semiquantitative evaluation of its content. Insight into other structural rearrangements was also obtained.
Topics: Fourier Analysis; Least-Squares Analysis; Protein Array Analysis; Protein Denaturation; Protein Structure, Secondary; Spectroscopy, Fourier Transform Infrared
PubMed: 34592098
DOI: 10.1021/acs.analchem.1c01416