Nitric oxide as a double-edged sword in pulmonary viral infections: Mechanistic insights and potential therapeutic implications

In the face of the global pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), researchers are tirelessly exploring novel therapeutic approaches to combat coronavirus disease 2019 (COVID-19) and its associated complications. Nitric oxide (NO) has appeared as a multifaceted signaling mediator with diverse and often contrasting biological activities. Its intricate biochemistry renders it a crucial regulator of cardiovascular and pulmonary functions, immunity, and neurotransmission. Perturbations in NO production, whether excessive or insufficient, contribute to the pathogenesis of various diseases, encompassing cardiovascular disease, pulmonary hypertension, asthma, diabetes, and cancer. Recent investigations have unveiled the potential of NO donors to impede SARS-CoV- 2 replication, while inhaled NO demonstrates promise as a therapeutic avenue for improving oxygenation in COVID-19-related hypoxic pulmonary conditions. Interestingly, NO's association with the inflammatory response in asthma suggests a potential protective role against SARS-CoV-2 infection. Furthermore, compelling evidence indicates the benefits of inhaled NO in optimizing ventilation-perfusion ratios and mitigating the need for mechanical ventilation in COVID-19 patients. In this review, we delve into the molecular targets of NO, its utility as a diagnostic marker, the mechanisms underlying its action in COVID-19, and the potential of inhaled NO as a therapeutic intervention against viral infections. The topmost significant pathway, gene ontology (GO)-biological process (BP), GO-molecular function (MF) and GO-cellular compartment (CC) terms associated with Nitric Oxide Synthase (NOS)1, NOS2, NOS3 were arginine biosynthesis (p-value = 1.15 x 10-9) regulation of guanylate cyclase activity (p-value = 7.5 x 10-12), arginine binding (p-value = 2.62 x 10-11), vesicle membrane (p-value = 3.93 x 10-8). Transcriptomics analysis further validates the significant presence of NOS1, NOS2, NOS3 in independent COVID-19 and pulmonary hypertension cohorts with respect to controls. This review investigates NO's molecular targets, diagnostic potentials, and therapeutic role in COVID-19, employing bioinformatics to identify key pathways and NOS isoforms' significance.

Sugar osmolyte inhibits and attenuates the fibrillogenesis in RNase A: An in vitro and in silico characterizations

Mechanisms of protein aggregation are of immense interest in therapeutic biology and neurodegenerative medicine. Biochemical processes within the living cell occur in a highly crowded environment. The phenomenon of macromolecular crowding affects the diffusional and conformational dynamics of proteins and modulates their folding. Macromolecular crowding is reported to cause protein aggregation in some cases, so it is a cause of concern as it leads to a plethora of neurodegenerative disorders and systemic amyloidosis. To divulge the mechanism of aggregation, it is imperative to study aggregation in well-characterized model proteins in the presence of macromolecular crowder. One such protein is ribonuclease A (RNase A), which deciphers neurotoxic function in humans; therefore we decided to explore the amyloid fibrillogenesis of this thermodynamically stable protein. To elucidate the impact of crowder, dextran-70 and its monomer glucose on the aggregation profile of RNase-A various techniques such as Absorbance, Fluorescence, Fourier Transforms Infrared, Dynamic Light Scattering and circular Dichroism spectroscopies along with imaging techniques like Atomic Force Microscopy and Transmission Electron Microscopy were employed. Thermal aggregation and fibrillation were further promoted by dextran-70 while glucose counteracted the effect of the crowding agent in a concentration-dependent manner. This study shows that glucose provides stability to the protein and prevents fibrillation. Intending to combat aggregation, which is the hallmark of numerous late-onset neurological disorders and systemic amyloidosis, this investigation unveils that naturally occurring osmolytes or other co-solutes can be further exploited in novel drug design strategies.

The lipid-lowering efficacy of rosuvastatin is associated with variations in SLCO1B1: a 12-month prospective cohort study

OBJECTIVE

Statins' efficacy and safety are subject to wide inter-individual variability, partly due to genetic predisposition. Studies have shown that the genetic variations in the common solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene polymorphisms affect the transport of statins' transport into hepatocytes, their plasma concentration, and circulation time. The ultimate result is variable and personalized statins response and statin-associated muscular symptoms (SAMS). Here we report an update on the differential response to rosuvastatin therapy in the Pakistani population.

PATIENTS AND METHODS

A total of 166 hyperlipidemic patients on rosuvastatin were prospectively followed for 24 weeks. Muscle symptoms were recorded after 6-8 weeks of therapy, and assessment was done according to the SAMS-clinical index tool. Patients were genotyped for SLCO1B1 c.521T>C and c.388A>G polymorphisms, for association with lipid-lowering response and statin-associated muscle symptoms. The plasma level of rosuvastatin was determined through Liquid chromatography-mass spectrometry (LCMS) for possible correlation with adverse effects and lipid-lowering efficacy.

RESULTS

Mean reduction in low-density lipoprotein cholesterol (LDL-C) was 42.34 mg/dl (p<0.001), 35.66 mg/dl (p<0.001), and 24.47 mg/dl (p=0.202) in reference, heterozygous and mutant homozygous groups of SLCO1B1 c.521T>C, respectively. A 15.70% and 42.14% diminished LDL-C reduction was observed in c.521TC and c.521CC, respectively, compared to the reference c.521TT genotype. Similarly, for SLCO1B1 c.388A>G, 20.50% and 29.40% less LDL-C lowering effect was observed in heterozygous and mutant homozygous carriers, respectively. SAMS were observed in 37% and 33% of heterozygous and minor homozygous, respectively, (p=0.059). The rosuvastatin plasma level was 1.89-fold higher in the c.521CC genotype than in the reference homozygous type.

CONCLUSIONS

Differential lipid-lowering response and muscular symptoms due to rosuvastatin are associated with the SLCO1B1 common polymorphisms. Further studies are needed to validate dose adjustment and rationalization.

Osmolytes: Wonder molecules to combat protein misfolding against stress conditions

The proper functioning of any protein depends on its three dimensional conformation which is achieved by the accurate folding mechanism. Keeping away from the exposed stress conditions leads to cooperative unfolding and sometimes partial folding, forming the structures like protofibrils, fibrils, aggregates, oligomers, etc. leading to several neurodegenerative diseases like Parkinson's disease, Alzheimer's, Cystic fibrosis, Huntington, Marfan syndrome, and also cancers in some cases, too. Hydration of proteins is necessary, which may be achieved by the presence of organic solutes called osmolytes within the cell. Osmolytes belong to different classes in different organisms and play their role by preferential exclusion of osmolytes and preferential hydration of water molecules and achieves the osmotic balance in the cell otherwise it may cause problems like cellular infection, cell shrinkage leading to apoptosis and cell swelling which is also the major injury to the cell. Osmolyte interacts with protein, nucleic acids, intrinsically disordered proteins by non-covalent forces. Stabilizing osmolytes increases the Gibbs free energy of the unfolded protein and decreases that of folded protein and vice versa with denaturants (urea and guanidinium hydrochloride). The efficacy of each osmolyte with the protein is determined by the calculation of m value which reflects its efficiency with protein. Hence osmolytes can be therapeutically considered and used in drugs.

Validation of analysis of arsenic in water samples using Wagtech Digital Arsenator

Groundwater, the only source of potable water for millions of people in Bangladesh during dry season, is often contaminated with arsenic (As) above the allowable drinking water limit of 50 μg/L. Testing well water--with arsenic field test kits (FTKs)--and switching to safe-wells can effectively reduce exposure to As. FTKs are low cost, provide fast results, and are commercially available. There are between 10 and 11 million shallow tubewells in Bangladesh. Approximately, 5 million have been tested using FTKs. FTKs with color comparator rely on visual identification for generating qualitative results, which may not be highly reliable at the lower range because human eyes have low sensitivity in this range and sensitivity varies from person to person. The Wagtech Digital Arsenator does not suffer from this limitation and should, in theory, be able to generate quantitative, accurate, and reliable results. The instrument has a linear range of 0-100 μg/L, an accuracy of ± 20% for the 50 μg/L quality control standards, and a detection limit of about 4.4 μg/L. All Arsenators employed in this investigation also displayed high bias for 50 μg/L arsenic standard and were calibrated in order to improve measurement accuracy and reliability. Analyses of 179 raw and 92 treated well waters in the field and in two analytical laboratories were found to be highly correlated with the Spearman rank correlation coefficient of ≥ 0.800, indicating that Arsenator results are perhaps nearly as accurate and reliable as those from analytical laboratories.