Targeting next-generation PDE4 inhibitors in search of potential management of rheumatoid arthritis and psoriasis.

Immune-mediated inflammatory diseases (IMIDs) comprise a broad spectrum of conditions characterized by systemic inflammation affecting various organs and tissues, for which there is no known cure. The isoform-specific inhibition of phosphodiesterase-4B (PDE4B) over PDE4D constitutes an effective therapeutic strategy for the treatment of IMIDs that minimizes the adverse effects associated with non-selective PDE4 inhibitors. Thus, we report a new class of isoquinolone derivatives as next-generation PDE4 inhibitors for effective management of rheumatoid arthritis (RA) and psoriasis. Among the series, 8 compounds i.e. 1e, 1l, 1m, 1n, 1o, 2m, 2o and 3o showed promising PDE4B inhibition (>80 %) in vitro with IC50 ∼ 1.4-6.2 µM. The compound 1l was identified as an initial hit and was pursued for further studies. According to structure-activity relationship (SAR), an allyl group at C-4 position improved PDE4B inhibition. The correlation between in vitro activity data and binding affinities obtained via molecular docking suggested that the high-affinity binding to PDE4B is a prerequisite for the effective inhibition of PDE4B. Notably, the hit 1l showed selectivity towards PDE4B over PDE4D in vitro. Furthermore, 1l treatment (30 mg/kg) in the adjuvant-induced arthritis (AIA) rat model induced by complete Freund's adjuvant (CFA) demonstrated anti-arthritic potential via ameliorating paw swelling and body weight, narrowing joint space, reducing excessive immune cells infiltration and pannus formation in addition to reducing mRNA expression of pro-inflammatory cytokines such as TNF-α and IL-6 in synovial tissues of experimental rats. Additionally, 1l reduced the hyper-proliferative state and colony forming potential of IMQ-induced psoriatic keratinocytes. The treatment of these cells with 1l markedly reduced the protein levels of Ki67 and mRNA levels of pro-inflammatory cytokines e.g. IL-17A and TNF-α suggesting its potent anti-psoriatic potential. Furthermore, 1l did not show any significant adverse effects when evaluated in a systematic toxicity (e.g. teratogenicity, hepatotoxicity and cardiotoxicity) studies in zebrafish at the tested concentrations (1-100 µM) and the NOAEL (no-observed-adverse-effect level) was found to be 100 µM. Thus, with promising anti-inflammatory effects both in vitro and in vivo along with PDE4B selectivity with an acceptable safety margin, 1l emerged as a new and promising inhibitor for further studies.

Clinical outcomes and the impact of valve morphology for transcatheter aortic valve replacement in bicuspid aortic valves: A systematic review and meta-analysis.

BACKGROUND: Bicuspid aortic valve (BAV) is present in approximately 0.5%-2% of the general population, causing significant aortic stenosis (AS) in 12%-37% of affected individuals. Transcatheter aortic valve replacement (TAVR) is being considered the treatment of choice in patients with symptomatic AS across all risk spectra. AIM: Aim Our study aims to compare TAVR outcomes in patients with BAV versus tricuspid aortic valves (TAV). METHODS: A comprehensive literature search was performed in PubMed, Web of Science, and Cochrane trials. Studies were included if they included BAV and TAV patients undergoing TAVR with quantitative data available for at least one of our predefined outcomes. Meta-analysis was performed by the random-effects model using Stata software. RESULTS: Fifty studies of 203,288 patients were included. BAV patients had increased 30-day all-cause mortality (odds ratio [OR] = 1.23 [1.00-1.50], p = 0.05), in-hospital stroke (OR = 1.39 [1.01-1.93], p = 0.05), in-hospital and 30-day PPI (OR = 1.13 [1.00-1.27], p = 0.04; OR = 1.16 [1.04-1.13], p = 0.01) and in-hospital, 30-day and 1-year aortic regurgitation (AR) (OR = 1.48 [1.19-1.83], p < 0.01; OR = 1.79 [1.26-2.52], p < 0.01; OR = 1.64 [1.03-2.60], p = 0.04). Subgroup analysis on new-generation valves showed a reduced 1-year all-cause mortality (OR = 0.86 [CI = 0.75-0.98], p = 0.03), despite higher in-hospital and 30-day PPI (OR = 0.1.21 [1.04-1.41], p = 0.01; OR = 1.17 [1.05-1.31], p = 0.01) and in-hospital AR (OR = 1.62 [1.14-2.31], p = 0.01) in the BAV group. The quality of included studies was moderate-to-high, and only three analyses presented high heterogeneity. CONCLUSION: TAVR is associated with comparable outcomes in patients with BAV and TAV. Careful selection of BAV cases by preprocedural assessment of valve anatomy and burden of calcification, pre- and post-procedural dilation, and implementing newer generations of valves may improve the safety and efficacy of TAVR in BAV patients.

Design, synthesis and evaluation of 2-aryl quinoline derivatives against 12R-lipoxygenase (12R-LOX): Discovery of first inhibitor of 12R-LOX.

The 12R-lipoxygenase (12R-LOX), a (non-heme) iron-containing metalloenzyme belonging to the lipoxygenase (LOX) family catalyzes the conversion of arachidonic acid (AA) to its key metabolites. Studies suggested that 12R-LOX plays a critical role in immune modulation for the maintenance of skin homeostasis and therefore can be considered as a potential drug target for psoriasis and other skin related inflammatory diseases. However, unlike 12-LOX (or 12S-LOX) the enzyme 12R-LOX did not receive much attention till date. In our effort, the 2-aryl quinoline derivatives were designed, synthesized and evaluated for the identification of potential inhibitors of 12R-hLOX. The merit of selection of 2-aryl quinolines was assessed by in silico docking studies of a representative compound (4a) using the homology model of 12R-LOX. Indeed, in addition to participating in H-bonding with THR628 and LEU635 the molecule formed a hydrophobic interaction with VAL631. The desired 2-aryl quinolines were synthesized either via the Claisen-Schmidt condensation followed by one-pot reduction-cyclization or via the AlCl3 induced heteroarylation or via the O-alkylation approach in good to high (82-95%) yield. When screened against human 12R-LOX (12R-hLOX) in vitro four compounds (e.g. 4a, 4d, 4e and 7b) showed encouraging (>45%) inhibition at 100 µM among which 7b and 4a emerged as the initial hits. Both the compounds showed selectivity towards 12R-hLOX over 12S-hLOX, 15-hLOX and 15-hLOXB and concentration dependent inhibition of 12R-hLOX with IC50 = 12.48 ± 2.06 and 28.25 ± 1.63 µM, respectively. The selectivity of 4a and 7b towards 12R-LOX over 12S-LOX was rationalized with the help of molecular dynamics simulations. The SAR (Structure-Activity Relationship) within the present series of compounds suggested the need of a o-hydroxyl group on the C-2 phenyl ring for the activity. The compound 4a and 7b (at 10 and 20 µM) reduced the hyper-proliferative state and colony forming potential of IMQ-induced psoriatic keratinocytes in a concentration dependent manner. Further, both compounds decreased the protein levels of Ki67 and the mRNA expression of IL-17A in the IMQ-induced psoriatic-like keratinocytes. Notably, 4a but not 7b inhibited the production of IL-6 and TNF-α in the keratinocyte cells. In the preliminary toxicity studies (i.e. teratogenicity, hepatotoxicity and heart rate assays) in zebrafish both the compounds showed low safety (<30 µM) margin. Overall, being the first identified inhibitors of 12R-LOX both 4a and 7b deserve further investigations.

Decoding the effects of spike receptor binding domain mutations on antibody escape abilities of omicron variants.

Recent times witnessed an upsurge in the number of COVID19 cases which is primarily attributed to the emergence of several omicron variants, although there is substantial population vaccination coverage across the globe. Currently, many therapeutic antibodies have been approved for emergency usage. The present study critically evaluates the effect of mutations observed in several omicron variants on the binding affinities of different classes of RBD-specific antibodies using a combined approach of immunoinformatics and binding free energy calculations. Our binding affinity data clearly show that omicron variants achieve antibody escape abilities by incorporating mutations at the immunogenic hotspot residues for each specific class of antibody. K417N and Y505H point mutations are primarily accountable for the loss of class I antibody binding affinities. The K417N/Q493R/Q498R/Y505H combined mutant significantly reduces binding affinities for all the class I antibodies. E484A single mutation, on the other hand, drastically reduces binding affinities for most of the class II antibodies. E484A and E484A/Q493R double mutations cause a 33-38% reduction in binding affinity for an approved therapeutic monoclonal antibody. The Q498R RBD mutation observed across all the omicron variants can reduce ∼12% binding affinity for REGN10987, a class III therapeutic antibody, and the L452R/Q498R double mutation causes a ∼6% decrease in binding affinities for another class III therapeutic antibody, LY-CoV1404. Our data suggest that achieving the immune evasion abilities appears to be the selection pressure behind the emergence of omicron variants.

Gender-specific outcomes after percutaneous left atrial appendage closure: A nationwide readmission database analysis.

INTRODUCTION: Thromboembolism-associated stroke is the most feared complication of atrial fibrillation (AF). Percutaneous left atrial appendage closure (pLAAC) is indicated for stroke prevention in patients with AF who can not tolerate long-term anticoagulation. We aim to study gender differences in peri-procedural and readmissions outcomes in pLAAC patients. METHODS: Using the national readmission database from January 2016 to December 2018, AF patients undergoing the pLAAC procedure were identified. We used multivariate logistic regression analyses and time-to-event Cox regression analyses to conduct the study. Propensity matching with the Greedy method was done for the accuracy of results. RESULT: A total of 28 819 patients were included in our study. Among them 11 946 (41.5%) were women and 16 873 (58.6%) were men. The mean age of overall population was 76.1 ± 8.5 years, with women ~1 year older than men. The overall rate of complications was higher in women (8.6% vs. 6.6%, p < .001), primarily driven by bleeding-related complications, that is, major bleed (odds ratio [OR]: 1.32 95% confidence interval [CI]: 1.03-1.69, p = .029), blood transfusion (OR: 1.45, 95% CI: 1.06-1.97, p = .019), and cardiac tamponade (OR: 1.80, 95% CI: 1.13-2.89, p = .014). Women had two times higher peri-procedural ischemic stroke. There was no difference in peri-procedural mortality. Women remained at 20% and 13% higher risk for readmission at 30 days and 6 months of discharge. CONCLUSION: Women had higher peri-procedural complications and were at higher risk of readmissions at 30 days and 6 months. However, there was no difference in mortality during the index hospitalization. Further studies are necessary to determine causality.

Outcomes of rotational atherectomy followed by cutting balloon versus plain balloon before drug-eluting stent implantation for calcified coronary lesions: A meta-analysis.

OBJECTIVE: The aim of this study is to compare outcomes of rotational atherectomy and cutting balloon (RACB) versus rotational atherectomy and plain balloon (RAPB) before drug-eluting stent (DES) implantation in calcified coronary lesions. METHODS: Randomized controlled trials (RCT) and observational studies comparing RACB with RAPB were identified through a systematic search of published literature across multiple databases. Random effect meta-analysis was performed to compare the outcome between the two groups. RESULTS: Four studies were included in the meta-analysis (three observational and one RCT) involving a total of 315 patients. 166 patients had RACB, and 149 patients had RAPB before DES placement with a median follow-up of 11.5 months. Compared with patients who had RAPB there was no difference in MACE (composite of death, myocardial infarction, and target vessel revascularization) (odds ratio [OR]: 0.74; 95% confidence interval [CI]: 0.25-2.18], slow flow/no reflow (OR: 0.71; 95% CI: 0.23-2.16), all-cause mortality (OR: 2.02; 95% CI: 0.28-14.60), and device success rate (OR: 1.79; 95% CI: 0.28-11.18) in the RACB approach. There was a benefit towards less target lesion revascularization in the RACB group; however, this outcome was reported in two studies (OR: 0.29; 95% CI: 0.08-0.99). On meta-regression there was no association between age, sex, diabetes, or lesion location with MACE and all-cause mortality. The studies were homogenous across all outcomes. CONCLUSION: RACB, as compared with RAPB, had a similar risk of MACE, all-cause mortality, device success, and complication, but a lower risk of target lesion revascularization.

Molecular Factors of Ice Growth Inhibition for Hyperactive and Globular Antifreeze Proteins: Insights from Molecular Dynamics Simulation.

The molecular mechanism behind the ice growth inhibition by antifreeze proteins (AFPs) is yet to be understood completely. Also, what physical parameters differentiate between the AFP and non-AFP are largely unknown. Thus, to get an atomistic overview of the differential antifreeze activities of different classes of AFPs, we have studied ice growth from different ice surfaces in the presence of a moderately active globular type III AFP and a hyperactive spruce budworm (sbw) AFP. Results are compared with the observations of ice growth simulations in the presence of topologically similar non-AFPs using all-atom molecular dynamics simulations. Simulation data suggest that the ice surface coverage is a critical factor in ice growth inhibition. Due to the presence of an ice binding surface (IBS), AFPs form a high affinity complex with ice, accompanied by a transition of hydration water around the IBS from clathrate-like to ice-like. Several residues around the periphery of the IBS anchor the AFP to the curved ice surface mediated by multiple strong hydrogen bonds, stabilizing the complex immensely. In the high surface coverage regime, the slow unbinding kinetics dominates over the ice growth kinetics and thus facilitates the ice growth inhibition. Due to the non-availability of a proper IBS, non-AFPs form a low-affinity complex with the growing ice surface. As a result, the non-AFPs are continuously repelled by the surface. If the concentration of AFPs is low, then the effective surface coverage is reduced significantly. In this low surface coverage regime, AFPs can also behave like impurities and are engulfed by the growing ice crystal.

Evolutionary and structural analysis elucidates mutations on SARS-CoV2 spike protein with altered human ACE2 binding affinity.

The recognition of ACE2 by the receptor-binding domain (RBD) of spike protein mediates host cell entry. The objective of the work is to identify SARS-CoV2 spike variants that emerged during the pandemic and evaluate their binding affinity with ACE2. Evolutionary analysis of 2178 SARS-CoV2 genomes identifies RBD variants that are under selection bias. The binding efficacy of these RBD variants to the ACE2 has been analyzed by using protein-protein docking and binding free energy calculations. Pan-proteomic analysis reveals 113 mutations among them 33 are parsimonious. Evolutionary analysis reveals five RBD variants A348T, V367F, G476S, V483A, and S494P are under strong positive selection bias. Variations at these sites alter the ACE2 binding affinity. A348T, G476S, and V483A variants display reduced affinity to ACE2 in comparison to the Wuhan SARS-CoV2 spike protein. While the V367F and S494P population variants display a higher binding affinity towards human ACE2. Reorientation of several crucial residues at the RBD-ACE2 interface facilitates additional hydrogen bond formation for the V367F variant which enhances the binding energy during ACE2 recognition. On the other hand, the enhanced binding affinity of S494P is attributed to strong interfacial complementarity between the RBD and ACE2.

Evolutionary and structural analysis elucidates mutations on SARS-CoV2 spike protein with altered human ACE2 binding affinity.

The recognition of ACE2 by the receptor-binding domain (RBD) of spike protein mediates host cell entry. The objective of the work is to identify SARS-CoV2 spike variants that emerged during the pandemic and evaluate their binding affinity with ACE2. Evolutionary analysis of 2178 SARS-CoV2 genomes identifies RBD variants that are under selection bias. The binding efficacy of these RBD variants to the ACE2 has been analyzed by using protein-protein docking and binding free energy calculations. Pan-proteomic analysis reveals 113 mutations among them 33 are parsimonious. Evolutionary analysis reveals five RBD variants A348T, V367F, G476S, V483A, and S494P are under strong positive selection bias. Variations at these sites alter the ACE2 binding affinity. A348T, G476S, and V483A variants display reduced affinity to ACE2 in comparison to the Wuhan SARS-CoV2 spike protein. While the V367F and S494P population variants display a higher binding affinity towards human ACE2. Reorientation of several crucial residues at the RBD-ACE2 interface facilitates additional hydrogen bond formation for the V367F variant which enhances the binding energy during ACE2 recognition. On the other hand, the enhanced binding affinity of S494P is attributed to strong interfacial complementarity between the RBD and ACE2.

30-day readmission following urgent and elective transcatheter aortic valve replacement: A Nationwide Readmission Database analysis.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is being increasingly used for decompensated severe symptomatic aortic stenosis. Data on urgent and elective TAVR readmission is scarce in the literature. Here, we have performed a retrospective cohort study with the Nationwide Readmission Database of 2016 to identify the rate of 30-day all-cause readmission, common causes of readmission, and distribution of morbidity in index admission and readmission after urgent and elective TAVR. METHODS: We used International Classification of Diseases, Tenth Revision codes (02R.F38H, 02R.F38Z, 02R.F48Z) for identification of all TAVR procedures done in 2016 in patients >18 years old. We found 8379 patients who underwent urgent TAVR and 32,006 patients who underwent elective TAVR in 2016. RESULT: The mean age of patients undergoing urgent TAVR was 79 ± 9.97 years with 44.6% women. The mean age of patients undergoing elective TAVR was 80.7 ± 8.25 years with 46.2% women. We found the 30-day all-cause readmission rate of 15.5% and 9.5% in patients undergoing urgent and elective TAVR, respectively (p < 0.001). The cardiac cause was the predominant cause of readmission in both groups (43.77% vs. 42.11%, p = 0.57), followed by pulmonary cause, gastrointestinal (GI) cause, and renal cause. Among cardiac causes, congestive heart failure (CHF) was predominant cause of readmission and was similar in both groups (18.73 in urgent TAVR vs. 15.73 in elective TAVR, p = 0.12). CONCLUSION: We found that the all-cause 30-day readmission rate was higher in patients who had undergone urgent TAVR. Further studies are needed to better understand this difference.

Readmission following urgent transcatheter aortic valve implantation versus urgent balloon aortic valvuloplasty in patients with decompensated heart failure or cardiogenic shock.

BACKGROUND: Urgent transcatheter aortic valve implantation (TAVI) is a feasible option for aortic stenosis (AS) patients with decompensated heart failure (HF) and cardiogenic shock (CS) as compared to the more traditional urgent balloon aortic valvuloplasty (BAV). OBJECTIVES: We conducted a retrospective analysis to compare risk and cause of readmission in these two high-risk groups. METHODS: Nationwide Readmission Database (NRD) 2011-2014 was retrospectively analyzed to identify patients with AS having either urgent TAVI or urgent BAV using appropriate ICD-9 codes. Propensity scores were used to match patients with urgent TAVI as compared to patients with urgent BAV. Statistical analysis was performed using the Stata 15.1 software. RESULTS: We identified a weighted sample of 6,670 patients with urgent BAV and 6,964 patients with urgent TAVI. The all-cause 30- and 90-day readmission was lower in the urgent TAVI group compared to urgent BAV (15.4 vs. 22.5%, (aHR): 0.92 [0.90-0.95] p < .001). 30-day readmission due to CV cause and HF was also lower in the urgent TAVI group (aHR, 0.93: p < .001 and aHR, 0.98: p = .040, respectively). The 30-day gastrointestinal (GI) bleed readmission rate was three times higher in urgent TAVI group (aHR, 3.00:95% CI (1.23-7.33), p = .016), but was not statistically significant at 90-days. Cardiac causes of readmission were the predominant cause of readmission in both groups, but more pronounced in urgent BAV group (60.3 vs. 40.5%, p < .001). CONCLUSION: Urgent TAVI appears beneficial in patients with AS and decompensated HF or CS driven by roughly 10 and 25% reductions in overall readmissions at 30 and 90 days, and marked reductions in reintervention, although offset partially by higher risk of readmission due to GI bleeding at 30 days.

Combined Structure and Ligand-Based Design of Selective Acetylcholinesterase Inhibitors.

Acetylcholinesterase is a prime target for therapeutic intervention in Alzheimer's disease. Acetylcholinesterase inhibitors (AChEIs) are used to improve cognitive abilities, playing therefore an important role in disease management. Drug repurposing screening has been performed on a corporate chemical library containing 11 353 compounds using a target fishing approach comprising three-dimensional (3D) shape similarity and pharmacophore modeling against an approved drug database, Drugbank. This initial screening identified 108 hits. Among them, eight molecules showed structural similarity to the known AChEI drug, pyridostigmine. Further structure-based screening using a pharmacophore-guided rescoring method identifies one more potential hit. Experimental evaluations of the identified hits sieve out a highly selective AChEI scaffold. Further lead optimization using a substructure search approach identifies 24 new potential hits. Three of the 24 compounds (compounds 10b, 10h, and 10i) based on a 6-(2-(pyrrolidin-1-yl)pyrimidin-4-yl)-thiazolo[3,2-a]pyrimidine scaffold showed highly promising AChE inhibition ability with IC50 values of 13.10 ± 0.53, 16.02 ± 0.46, and 6.22 ± 0.54 µM, respectively. Moreover, these compounds are highly selective toward AChE. Compound 10i shows AChE inhibitory activity similar to a known Food and Drug Administration (FDA)-approved drug, galantamine, but with even better selectivity. Interaction analysis reveals that hydrophobic and hydrogen-bonding interactions are the primary driving forces responsible for the observed high affinity of the compound with AChE.

Targeted DNA oxidation and trajectory of radical DNA using DFT based QM/MM dynamics.

Molecular insight into electronic rearrangements and structural trajectories arising from oxidative damages to DNA backbone is of crucial importance in understanding the effect of ionizing radiation, developing DNA biosensors and designing effective DNA cleaving molecules. Employing a Density Functional Theory based multi-scale Quantum-Mechanical-Molecular-Mechanical (QM/MM) simulation and a suitable partitioning of the Hamiltonian on solvated nucleotide, and single-, and double-stranded DNA, we mimic hydrogen transfer reactions from the backbone by OH radicals and report structural trajectories arising from on-the-fly electronic charge- and spin-density redistribution in these three different structural topologies of DNA. Trajectories reveal that H4' abstraction can disrupt the deoxyribose moiety through the formation of C4'=O4' ketone and a π-bond with base at C1'-N9 in a nucleotide versus only partial ketone formation in single- and double-stranded DNA, where the orientation of the base is topologically restrained. However, H5' abstraction can lead DNA cleavage at 5' end through the formation of C5'=O5' ketone and breakage of P-O5' bond. Results demonstrate that structural damages from oxidative reactions are restrained by base stacking and base-pair hydrogen bonding. The methodology can be suitably used to study targeted DNA and RNA damages from radicals and radiomimetic drugs to design DNA cleaving molecules for chemotherapy.

Ordered hydration layer mediated ice adsorption of a globular antifreeze protein: mechanistic insight.

The ice/water interface recognition mechanism of antifreeze proteins (AFPs) is highly contentious. Conventionally, protein adsorption on a solid surface is primarily driven by the polar interactions between the hydrophilic residues of the protein and interfacial water of the solid surface. Ice surface recognition by a type III AFP is surprising in this context where the ice binding surface (IBS) is hydrophobic. The present study provides molecular insight into the unusual interface recognition phenomenon of a type III AFP (QAE isoform) from Macrozoarces americanus. Potential of mean force calculations show that the type III AFP adsorbs on the ice surface mediated through a layer of ordered water. Molecular dynamics simulations at lower than ambient temperature reveal that the flat hydrophobic IBS induces ordering of water. The excellent geometrical synergy between the hydration water structure around the IBS and water arrangements on the pyramidal surface favours adsorption on the pyramidal plane. Mutations that interrupt the hydration shell water ordering essentially lead to less efficient adsorption, which greatly reduces the anti-freezing activity of the AFP. Binding free energy calculations of the wild-type and several mutant AFPs reveal that the binding affinity is linearly correlated with the experimentally observed thermal hysteresis activity. Therefore, binding to a specific ice plane with considerable affinity is the dictating factor of the anti-freeze activity for a type III AFP. Mechanistic insights into the ice binding process of the wild-type and different mutant AFPs obtained from this study pave the way for rational design of type III variants with much improved activity, which possesses ample industrial applicability, particularly in cryo-preservation.

Lycopene Prevents Mitochondrial Dysfunction during d-Galactosamine/Lipopolysaccharide-Induced Fulminant Hepatic Failure in Albino Rats.

Functional perturbation of mitochondria is associated with fulminant hepatic failure (FHF). d-Galactosamine/lipopolysaccharide (d-GalN/LPS)-induced FHF is a renowned model to evaluate the efficacy of hepatoprotective agents. Lycopene is an antioxidant and phytonutrient from the carotenoid family. The health benefits of lycopene are prominent against cancer and cardiovascular, lung, liver, and skin problems. Recent studies have demonstrated the hepatoprotective, antidyslipidemic, and antioxidant roles of lycopene. The current study was designed to appraise the ability of lycopene to prevent mitochondrial dysfunction during the d-GalN/LPS-induced FHF. The administration of d-GalN/LPS (300 mg and 30 µg/kg body weight, respectively) to the experimental rats induced several disturbances in mitochondrial function. The lipid peroxide and hydrogen peroxide levels were increased (p < 0.05). The activities of mitochondrial antioxidants, tricarboxylic acid (TCA) cycle, and electron transport chain enzymes and the cellular adenosine triphosphate (ATP) content were decreased (p < 0.05). Lycopene (10 mg/kg body weight for 6 days) pretreatment attenuated lipid peroxidation and prohibited the excessive synthesis of hydrogen peroxide. The d-GalN/LPS-induced impairment in ATP production and increased enzyme activities were effectively prevented by the lycopene administration. The lycopene-mediated mitochondrial protection was mainly ascribed to the strong antioxidant potential of this phytonutrient. Molecular modeling results obtained show evidence that lycopene inhibits several lipoxygenases and provides rationale for the observed prevention of lipid peroxidation in the mitochondrial membrane. The carotenoid lycopene combatted oxidative stress, scavenged free radicals, prevented ROS generation, and inhibited the toxic effects of d-GalN/LPS during FHF.

Molecular Insight into the Adsorption of Spruce Budworm Antifreeze Protein to an Ice Surface: A Clathrate-Mediated Recognition Mechanism.

The principal mechanism of ice recognition by antifreeze protein (AFP) has been a topic of intense discussion in recent times. Despite many experimental and theoretical studies, the detailed understanding of the process remains elusive. The present work aims to explore the molecular mechanism of ice recognition by an insect AFP from the spruce budworm, sbwAFP. As evident from our simulation, the water dynamics becomes very sluggish around the ice binding surface (IBS) as a result of the combined effect of confinement and ordering induced by the perfectly aligned methyl side chains of threonine residues, the THR ladder. The hydroxyl groups of threonine form strong hydrogen bonds with few of those highly ordered water molecules that are close to the THR ladder, which is the origin of anchored clathrate water at the IBS of sbwAFP. We propose anchored clathrate-mediated basal plane recognition by sbwAFP. The AFP adsorbed on the basal plane through water clathrate framed around the IBS. The surface of the basal plane and anchored clathrate water completes the caging around the threonine residues, which is the origin of the binding plane specificity of sbwAFP. This adsorbed AFP-ice complex undergoes dynamic crossover to a hydrogen-bonded complex within the thermal hysteresis (TH) regime of this particular AFP. The anchored clathrate water becomes part of the newly grown basal front as a result of the geometrical matches between the basal plane and the anchored clathrate water repeat distance. This observation provides a structural rationale for the experimentally observed time-dependent increase in TH activity for insect AFP. Our study proposes clathrate-mediated ice recognition by AFP and elucidates the dynamic events involved during ice binding by the insect AFP.

Conformational and hydration properties modulate ice recognition by type I antifreeze protein and its mutants.

The mechanism of ice recognition by antifreeze protein (AFP) is a topic of recent interest. Here, using equilibrium simulations and free energy calculations, we provide structural rationale to the observed experimental anomalies on type I AFP (wfAFP isoform HPLC6) and its mutants as well as probe the molecular origin of ice recognition by them. Our results clearly demonstrate that the interplay between the conformational and hydration properties dictates the ice binding ability of type I AFP and its mutants. We find that HPLC6 exists as a highly stable long helix which adsorbs on the ice surface through the ordered water cages around the CH3 group of threonine (THR) residues, rather than directly binding to the ice surface via threonine (THR) through hydrogen bonding. Upon mutating THR with serine (SER), the straight helix conformation of HPLC6 disappears and the most stable conformation is a kinked helix devoid of ice binding ability. Free energy calculations reveal that there is a dynamic equilibrium between straight and bent helical conformations in the case of a valine (VAL) mutant. The straight long helical form of the VAL mutant also has the ability to form an ordered water cage structure around the CH3 groups of the VAL residues and thereby efficiently adsorbs on an ice plane similar to the wild type AFP.

A sensitive fluorescent probe for the polar solvation dynamics at protein-surfactant interfaces.

Relaxation dynamics at the surface of biologically important macromolecules is important taking into account their functionality in molecular recognition. Over the years it has been shown that the solvation dynamics of a fluorescent probe at biomolecular surfaces and interfaces account for the relaxation dynamics of polar residues and associated water molecules. However, the sensitivity of the dynamics depends largely on the localization and exposure of the probe. For noncovalent fluorescent probes, localization at the region of interest in addition to surface exposure is an added challenge compared to the covalently attached probes at the biological interfaces. Here we have used a synthesized donor-acceptor type dipolar fluorophore, 6-acetyl-(2-((4-hydroxycyclohexyl)(methyl)amino)naphthalene) (ACYMAN), for the investigation of the solvation dynamics of a model protein-surfactant interface. A significant structural rearrangement of a model histone protein (H1) upon interaction with anionic surfactant sodium dodecyl sulphate (SDS) as revealed from the circular dichroism (CD) studies is nicely corroborated in the solvation dynamics of the probe at the interface. The polarization gated fluorescence anisotropy of the probe compared to that at the SDS micellar surface clearly reveals the localization of the probe at the protein-surfactant interface. We have also compared the sensitivity of ACYMAN with other solvation probes including coumarin 500 (C500) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM). In comparison to ACYMAN, both C500 and DCM fail to probe the interfacial solvation dynamics of a model protein-surfactant interface. While C500 is found to be delocalized from the protein-surfactant interface, DCM becomes destabilized upon the formation of the interface (protein-surfactant complex). The timescales obtained from this novel probe have also been compared with other femtosecond resolved studies and molecular dynamics simulations.

Insights into molecular therapy of glioma: current challenges and next generation blueprint.

Glioma accounts for the majority of human brain tumors. With prevailing treatment regimens, the patients have poor survival rates. In spite of current development in mainstream glioma therapy, a cure for glioma appears to be out of reach. The infiltrative nature of glioma and acquired resistance substancially restrict the therapeutic options. Better elucidation of the complicated pathobiology of glioma and proteogenomic characterization might eventually open novel avenues for the design of more sophisticated and effective combination regimens. This could be accomplished by individually tailoring progressive neuroimaging techniques, terminating DNA synthesis with prodrug-activating genes, silencing gliomagenesis genes (gene therapy), targeting miRNA oncogenic activity (miRNA-mRNA interaction), combining Hedgehog-Gli/Akt inhibitors with stem cell therapy, employing tumor lysates as antigen sources for efficient depletion of tumor-specific cancer stem cells by cytotoxic T lymphocytes (dendritic cell vaccination), adoptive transfer of chimeric antigen receptor-modified T cells, and combining immune checkpoint inhibitors with conventional therapeutic modalities. Thus, the present review captures the latest trends associated with the molecular mechanisms involved in glial tumorigenesis as well as the limitations of surgery, radiation and chemotherapy. In this article we also critically discuss the next generation molecular therapeutic strategies and their mechanisms for the successful treatment of glioma.

Tuning excited-state proton transfer dynamics of a 3-hydroxychromone dye in supramolecular complexes via host-guest steric compatibility.

The photophysics of 2-(2'-benzofuryl)-3-hydroxychromone (BFHC) is remarkably modulated in its complexes with macrocyclic hosts such as ß-cyclodextrin (ß-CD), hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and methyl-ß-cyclodextrin (M-ß-CD). BFHC exhibits dual emission bands, attributable to excited normal (N*) and tautomer (T*) forms, where the latter originates from the former through an excited-state intramolecular proton transfer (ESIPT) reaction. Fluorescence lifetimes of the tautomer, along with the intensity ratio (IT*/IN*) of the dual emission bands, and the fluorescence quantum yield (Φ) of the dye, increase significantly in the order ß-CD < HP-ß-CD < M-ß-CD to indicate increasing hydrophobicity of the dye environment in the host CD cavity. In accordance with this increasing hydrophobicity of the dye environment, the ESIPT dynamics of BFHC becomes increasingly fast in the host cavity in the order ß-CD < HP-ß-CD < M-ß-CD. Binding constant data and molecular modeling studies indicate that the increasing order of the faster ESIPT dynamics originates from an increasingly tight host-guest spatial fit, which causes increasingly strong dehydration of the BFHC dye. Steric compatibility in size and shape between the host cavity and the guest, which modulates the tightness of the host-guest spatial fit and hence the extent of hydration, is a key factor for tuning the proton transfer dynamics since water molecules perturb the ESIPT reaction and quench the fluorescence of BFHC.