The structure of the monobactam-producing thioesterase domain of SulM forms a unique complex with the upstream carrier protein domain.

Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an assembly line strategy in which the growing peptide is tethered to carrier domains that deliver the intermediates to neighboring catalytic domains. While most NRPS domains catalyze standard chemistry of amino acid activation, peptide bond formation and product release, some canonical NRPS catalytic domains promote unexpected chemistry. The paradigm monobactam antibiotic sulfazecin is produced through the activity of a terminal thioesterase domain that catalyzes an unusual ß-lactam forming reaction in which the nitrogen of the C-terminal N-sulfo-2,3-diaminopropionate residue attacks its thioester tether to release the ß-lactam product. We have determined the structure of the thioesterase domain as both a free-standing domain and a didomain complex with the upstream holo peptidyl-carrier domain. The structure illustrates a constrained active site that orients the substrate properly for ß-lactam formation. In this regard, the structure is similar to the ß-lactone forming thioesterase domain responsible for the production of obafluorin. Analysis of the structure identifies features that are responsible for this four-membered ring closure and enable bioinformatic analysis to identify additional, uncharacterized ß-lactam-forming biosynthetic gene clusters by genome mining.

Development and in-depth characterization of BRAFi-resistant melanoma cell lines in vitro and in vivo.

Regardless of the clinical response and improved patient survival observed following treatment with BRAFi like Vemurafenib (Vem), rapid development of resistance still remains as a major obstacle in melanoma therapy. In this context, we developed and characterized two acquired Vem-resistant melanoma cell lines, A375V and SK-MEL-28V, and an intrinsically Vem-resistant cell line, RPMI-7951. Altered morphology and growth rate of the resistant cell lines displayed spindle-shaped cells with filopodia formation and enhanced proliferation rate as compared to parental cells. Further in vitro characterization in 2D models confirmed the emergence of a resistant phenotype in melanoma cells. To mimic the in vivo tumor microenvironment, spheroids were developed for both parental and resistant cell lines to recognize materialization of invadopodia structures demonstrating elevated invasiveness and proliferation of resistant cells-based spheroids, especially A375V. Importantly, we validated A375V cell line in vivo to prove its tumorigenicity and drug resistance in tumor xenograft model. Taken together, our established clinically relevant Vem-resistant tumor model could be beneficial to elucidate drug resistance mechanisms, screen and identify novel anticancer therapies to overcome BRAFi resistance in melanoma.

Reply to Jalink, M.B. Comment on "Senthilkumaran et al. Bilateral Simultaneous Optic Neuritis Following Envenomations by Indian Cobra and Common Krait. Toxins 2022, 14, 805".

We thank the author for showing interest in our article [...].

Embracing cancer complexity: Hallmarks of systemic disease.

The last 50 years have witnessed extraordinary developments in understanding mechanisms of carcinogenesis, synthesized as the hallmarks of cancer. Despite this logical framework, our understanding of the molecular basis of systemic manifestations and the underlying causes of cancer-related death remains incomplete. Looking forward, elucidating how tumors interact with distant organs and how multifaceted environmental and physiological parameters impinge on tumors and their hosts will be crucial for advances in preventing and more effectively treating human cancers. In this perspective, we discuss complexities of cancer as a systemic disease, including tumor initiation and promotion, tumor micro- and immune macro-environments, aging, metabolism and obesity, cancer cachexia, circadian rhythms, nervous system interactions, tumor-related thrombosis, and the microbiome. Model systems incorporating human genetic variation will be essential to decipher the mechanistic basis of these phenomena and unravel gene-environment interactions, providing a modern synthesis of molecular oncology that is primed to prevent cancers and improve patient quality of life and cancer outcomes.

Exploring the causes of COPD misdiagnosis in primary care: A mixed methods study.

BACKGROUND: Within primary care there exists a cohort of patients misdiagnosed with Chronic Obstructive Pulmonary Disease (COPD). Misdiagnosis can have a detrimental impact on healthcare finances and patient health and so understanding the factors leading to misdiagnosis is crucial in order to reduce misdiagnosis in the future. The objective of this study is to understand and explore the perceived causes of COPD misdiagnosis in primary care. METHODS: A sequential mixed methods study, quantifying prevalence and features of patients misdiagnosed with COPD in primary care followed by a qualitative analysis to explore perceived causes of misdiagnosis. Quantitative data was collected for 206 patients identified as misdiagnosed with COPD within the INTEGR COPD study (NCT03482700). Qualitative data collected from 21 healthcare professionals involved in providing COPD care and 8 misdiagnosed patients who were recruited using a maximum variation purposive sampling. RESULTS: Misinterpretation of spirometry results was the prevailing factor leading to patients initially being misdiagnosed with COPD, affecting 59% of misdiagnosed patients in this cohort. Of the 99 patients who were investigated for their underlying diagnosis; 41% had normal spirometry and 40% had asthma. Further investigation through qualitative methodology uncovered reluctance to challenge historical misdiagnoses and challenges in differential diagnosis as the underlying explanations for COPD misdiagnosis in this cohort. CONCLUSIONS: Patients historically diagnosed with COPD without spirometric evidence are at risk of remaining labelled and treated for COPD despite non-obstructive respiratory physiology, leading to a persistent cohort of patients misdiagnosed with COPD in primary care. The lack of spirometry services during and after the COVID19 pandemic in primary care risks adding to the cohort of misdiagnosed patients. Support from respiratory specialists can potentially help to reduce the prevalence of COPD misdiagnosis in primary care. TRIAL REGISTRATION: NCT03482700.

Differential effects of the venoms of Russell's viper and Indian cobra on human myoblasts.

Local tissue damage following snakebite envenoming remains a poorly researched area. To develop better strategies to treat snakebites, it is critical to understand the mechanisms through which venom toxins induce envenomation effects including local tissue damage. Here, we demonstrate how the venoms of two medically important Indian snakes (Russell's viper and cobra) affect human skeletal muscle using a cultured human myoblast cell line. The data suggest that both venoms affect the viability of myoblasts. Russell's viper venom reduced the total number of cells, their migration, and the area of focal adhesions. It also suppressed myogenic differentiation and induced muscle atrophy. While cobra venom decreased the viability, it did not largely affect cell migration and focal adhesions. Cobra venom affected the formation of myotubes and induced atrophy. Cobra venom-induced atrophy could not be reversed by small molecule inhibitors such as varespladib (a phospholipase A2 inhibitor) and prinomastat (a metalloprotease inhibitor), and soluble activin type IIb receptor (a molecule used to promote regeneration of skeletal muscle), although the antivenom (raised against the Indian 'Big Four' snakes) has attenuated the effects. However, all these molecules rescued the myotubes from Russell's viper venom-induced atrophy. This study demonstrates key steps in the muscle regeneration process that are affected by both Indian Russell's viper and cobra venoms and offers insights into the potential causes of clinical features displayed in envenomed victims. Further research is required to investigate the molecular mechanisms of venom-induced myotoxicity under in vivo settings and develop better therapies for snakebite-induced muscle damage.

Aldehyde-mediated inhibition of asparagine biosynthesis has implications for diabetes and alcoholism.

Patients with alcoholism and type 2 diabetes manifest altered metabolism, including elevated aldehyde levels and unusually low asparagine levels. We show that asparagine synthetase B (ASNS), the only human asparagine-forming enzyme, is inhibited by disease-relevant reactive aldehydes, including formaldehyde and acetaldehyde. Cellular studies show non-cytotoxic amounts of reactive aldehydes induce a decrease in asparagine levels. Biochemical analyses reveal inhibition results from reaction of the aldehydes with the catalytically important N-terminal cysteine of ASNS. The combined cellular and biochemical results suggest a possible mechanism underlying the low asparagine levels in alcoholism and diabetes. The results will stimulate research on the biological consequences of the reactions of aldehydes with nucleophilic residues.

Application of 3D printing technology for the development of dose adjustable geriatric and pediatric formulation of celecoxib.

Developing safe and effective formulations for the geriatric and pediatric population is a challenging task due to issues of swallowability and palatability. The lack of standardized procedures for pediatric formulations further complicates the process. Manipulating adult formulations for children can lead to suboptimal efficacy and safety concerns. To overcome these challenges, minitablets or spinklets are preferred for the geriatric and pediatric population due to their smaller size and flexible dose adjustment. The aim of this study is the development of a 3D printed spinklets formulation of celecoxib, a nonsteroidal anti-inflammatory drug, using hot melt extrusion to address the limitations of traditional manufacturing methods. Three different formulations of celecoxib were prepared using Poly-2-ethyl-tetra-oxazoline (Aquazol) with and without surfactant. Subsequently, the mechanical properties and solubility of the drug-loaded filaments were evaluated. Solid state characterization confirmed the drug conversion into an amorphous form during the extrusion process, Computer-aided design software facilitate sprinklets design for fused deposition modeling and scanning electron microscopy assess the surface morphology. Sophorolipids plasticize better than TPGS, resulting in lowering processing temperatures during melt extrusion. In vitro drug release showed successful enhancements in the dissolution of oral medications for pediatric patients, considering their distinctive physiological characteristics. Overall, this study demonstrates the successful development of PEtOx-based 3D printed celecoxib sprinklets by coupling hot-melt extrusion and 3D printing technology. Future exploration holds the potential to revolutionize pharmaceutical production and advance personalized medication formulations.

Epitaxially Grown Mechanically Robust 2D Thin Film of Secondary Interactions Led Molecularly Woven Material.

Molecularly woven materials with striking mechanical resilience, and 2D controlled topologies like textiles, fishing nets, and baskets are highly anticipated. Molecular weaving exclusively apprehended by the secondary interactions expanding to laterally grown 2D self-assemblies with retained crystalline arrangement is stimulating. The interlacing entails planar molecules screwed together to form 2D woven thin films. Here, secondary interactions led 2D interlaced molecularly woven material (2° MW) built by 1D helical threads of organic chromophores twisted together via end-to-end CH···O connections, held strongly at inter-crossing by multiple OH···N interactions to prevent slippage is presented. Whereas, 1D helical threads with face-to-face O-H···O connections sans interlacing led the non-woven material (2° NW). The polarity-driven directionality in 2° MW led the water-actuated epitaxial growth of 2D-sheets to lateral thin films restricted to nano-scale thickness. The molecularly woven thin film is self-healing, flexible, and mechanically resilient in nature, while maintaining the crystalline regularity is attributed to the supple secondary interactions (2° ).

Cluster randomised controlled trial of specialist-led integrated COPD care (INTEGR COPD).

OBJECTIVE: Studies in hospital settings demonstrate that there is greater guideline adherence when care is delivered by a respiratory specialist, however, this has not been explored in primary care. The aim of this study is to determine the impact integrating respiratory specialists into primary care has on the delivery of guideline adherent chronic obstructive pulmonary disease (COPD) care. METHODS: 18 general practitioner (GP) practices were randomised to provide either usual or specialist-led COPD care. Patients at participating practices were included if they had an existing diagnosis of COPD. Outcomes were measured at the individual patient level. The primary outcome was guideline adherence, assessed as achieving four or more items of the COPD care bundle. Secondary outcome measures included quality of life, number of exacerbations, number of COPD-related hospitalisations and respiratory outpatient attendances. RESULTS: 586 patients from 10 practices randomised to the intervention and 656 patients from 8 practices randomised to the control arm of the study were included. The integration of respiratory specialists into GP practices led to a statistically significant (p<0.001) improvement in the provision of guideline adherent care when compared with usual care in this cohort (92.7% vs 70.1%) (OR 4.14, 95% CI 2.14 to 8.03). CONCLUSION: This is the first study to demonstrate that guideline adherence is improved through the integration of respiratory specialists into GP practices to deliver annual COPD reviews. To facilitate changes in current healthcare practice and policy, the findings of this paper need to be viewed in combination with qualitative research exploring the acceptability of specialist integration. TRIAL REGISTRATION NUMBER: NCT03482700.

Antibacterial and Antiviral Properties of Chenopodin-Derived Synthetic Peptides.

Antimicrobial peptides have been developed based on plant-derived molecular scaffolds for the treatment of infectious diseases. Chenopodin is an abundant seed storage protein in quinoa, an Andean plant with high nutritional and therapeutic properties. Here, we used computer- and physicochemical-based strategies and designed four peptides derived from the primary structure of Chenopodin. Two peptides reproduce natural fragments of 14 amino acids from Chenopodin, named Chen1 and Chen2, and two engineered peptides of the same length were designed based on the Chen1 sequence. The two amino acids of Chen1 containing amide side chains were replaced by arginine (ChenR) or tryptophan (ChenW) to generate engineered cationic and hydrophobic peptides. The evaluation of these 14-mer peptides on Staphylococcus aureus and Escherichia coli showed that Chen1 does not have antibacterial activity up to 512 µM against these strains, while other peptides exhibited antibacterial effects at lower concentrations. The chemical substitutions of glutamine and asparagine by amino acids with cationic or aromatic side chains significantly favoured their antibacterial effects. These peptides did not show significant hemolytic activity. The fluorescence microscopy analysis highlighted the membranolytic nature of Chenopodin-derived peptides. Using molecular dynamic simulations, we found that a pore is formed when multiple peptides are assembled in the membrane. Whereas, some of them form secondary structures when interacting with the membrane, allowing water translocations during the simulations. Finally, Chen2 and ChenR significantly reduced SARS-CoV-2 infection. These findings demonstrate that Chenopodin is a highly useful template for the design, engineering, and manufacturing of non-toxic, antibacterial, and antiviral peptides.

Biomimetic Helical Hydrogen Bonded Organic Framework Membranes for Efficient Uranium Recovery from Seawater.

Inspired by the uranyl-imidazole interactions via nitrogen's (N's) of histidine residues in single helical protein assemblies with open framework geometry that allows through migration/coordination of metal ions. Here, preliminary components of a stable hydrogen-bonded organic framework (HOF) are designed to mimic the stable single helical open framework with imidazole residues available for Uranium (U) binding. The imidazolate-HOF (CSMCRIHOF2-S) is synthesized with solvent-directed H-bonding in 1D array and tuned hydrophobic CH-π interactions leading to single helix pattern having enhanced hydrolytic stability. De-solvation led CSMCRIHOF2-P with porous helical 1D channels are transformed in a freestanding thin film that showcased improved mass transfer and adsorption of uranyl carbonate. CSMCRIHOF2-P thin film can effectively extract ≈14.8 mg g-1 in 4 weeks period from natural seawater, with > 1.7 U/V (Uranium to Vanadium ratio) selectivity. This strategy can be extended for rational designing of hydrolytically stable, U selective HOFs to realize the massive potential of the blue economy toward sustainable energy.

Delineating effect of headgroup and preparation method on transfection versus toxicity of DNA-loaded lipid nanocarriers.

Aim: To perform a parallel comparison of key parameters affecting the safety and efficiency of lipid-based nanovectors (i.e., complexing headgroups, composition and preparation method). Materials & methods: Various cationic and ionizable headgroups were screened for formulating lipoplexes with GFP-plasmid DNA. Ethanol injection and microfluidics were used to prepare nanoparticles with GFP-plasmid DNA complexed on the surface or within the interior of lipid bilayers. Results: Lipoplexes composed of sphingomyelin 102 exhibited the highest transfection efficiency given their higher cellular uptake in BRAF inhibitor-resistant melanoma cells. Lipid nanoparticles demonstrated acceptable transfection efficiency and high spheroid penetration while protecting plasmid DNA under simulated physiological conditions. Conclusion: Selecting the right complexing lipid and preparation method is critical for developing lipid nanocarriers to treat intractable diseases.

Certain genetic diseases or cancers can be treated with gene therapy. This involves the delivery of working genes to cells with a faulty copy. These genes are often contained in a circular piece of DNA called a plasmid. Plasmids can be delivered by a variety of structures called vectors. These vectors include altered viruses as well as lipid-based nanovectors, which are nanoscale spheres of phospholipids, a type of fat. Plasmids can either be internalized inside these spheres in lipid nanoparticles (LNPs) or attached to the surface in nanocomplexes. A section of the phospholipid called the headgroup faces outward in lipid-based nanovectors. The chemical makeup of these headgroups determines the function of the lipid-based nanovector. This study aimed to determine an optimal lipid-based nanovector in gene delivery by testing a variety and identifying which was most effective at delivering a gene that makes cells fluoresce green when successfully delivered. The more intense the fluorescence, the greater the degree of successful gene delivery. This study found that LNPs were more effective at delivering plasmid DNA than nanocomplexes and were safer and protected plasmid DNA better. The best performing LNP contained the lipid sphingomyelin 102, which is biodegradable. Therefore, the optimized LNP formulation employing sphingomyelin 102 as a biodegradable lipid could be an efficient nonviral gene-delivery system and will be further investigated to target drug-resistant melanoma, a type of skin cancer.

In Vitro Assessment of Cisplatin/Hyaluronan Complex for Loco-Regional Chemotherapy.

Loco-regional chemotherapy is a strategy used to achieve more precise anticancer drug effect directly on tumor mass, while decreasing whole body exposure, which can lead to undesirable side effects. Thus, the loco-regional chemotherapy is conceptually similar to the targeted drug delivery systems for delivering chemotherapeutics to cancer cells in a certain location of the body. Recently, it has been demonstrated that a novel polymeric film containing the complex between cisplatin (cisPt) and hyaluronan (sodium salt of hyaluronic acid; NaHA) enhanced in vivo efficacy and safety of cisplatin (cisPt) by loco-regional delivery in pleural mesothelioma. Biologically, hyaluronic acid (HA) binds with the CD44 receptor, which is a transmembrane glycoprotein overexpressed by other cancer cells. Thus, administering both cisPt and hyaluronan together as a complex loco-regionally to the tumor site could target cancer cells locally and enhance treatment safety. A slight excess of hyaluronan was required to have more than 85% cisPt complexation. In cell monolayers (2D model) the cisPt/NaHA complex in solution demonstrated dose- and time-dependent cytotoxic effect by decreasing the viability of pancreatic, melanoma, and lung cell lines (they all express CD44). At the same concentration in solution, the complex was as effective as cisPt alone. However, when applied as film to melanoma spheroids (3D model), the complex was superior because it prevented the tumor spheroid growth and, more importantly, the formation of new cell colonies. Hence, cisPt/NaHA complex could work in preventing metastases loco-regionally and potentially avoiding systemic relapses.

Formaldehyde regulates S-adenosylmethionine biosynthesis and one-carbon metabolism.

One-carbon metabolism is an essential branch of cellular metabolism that intersects with epigenetic regulation. In this work, we show how formaldehyde (FA), a one-carbon unit derived from both endogenous sources and environmental exposure, regulates one-carbon metabolism by inhibiting the biosynthesis of S-adenosylmethionine (SAM), the major methyl donor in cells. FA reacts with privileged, hyperreactive cysteine sites in the proteome, including Cys120 in S-adenosylmethionine synthase isoform type-1 (MAT1A). FA exposure inhibited MAT1A activity and decreased SAM production with MAT-isoform specificity. A genetic mouse model of chronic FA overload showed a decrease n SAM and in methylation on selected histones and genes. Epigenetic and transcriptional regulation of Mat1a and related genes function as compensatory mechanisms for FA-dependent SAM depletion, revealing a biochemical feedback cycle between FA and SAM one-carbon units.

Potential Roles of Activin in Head and Neck Squamous Cell Carcinoma Progression and Mortality.

BACKGROUND/AIM: Activin, a member of the TGF-ß super family of cytokines, is involved in head and neck squamous cell carcinoma (HNSCC). This study examined the constituents of the activin axis in order to further elucidate the role of activin A in HNSCC progression. MATERIALS AND METHODS: Immunohistochemistry (IHC), reverse transcription polymerase chain reaction (RT-PCR), MTT, and matrigel invasion assays, in addition to analysis of the tumor cancer genome atlas (TCGA), were employed. RESULTS: IHC in HNSCC and oral leukoplakia (OPL) lesions demonstrated increased expression of the inhibin subunit ßA (INHBA) (p<0.0001), as well as activin receptor type IB (ACVR1B) (p<0.0032) compared to normal mucosa. TCGA analysis revealed increased INHBA expression was associated with lymph node positive tumors (p=0.024), decreased overall survival (p=0.0167), and decreased promoter methylation (p<0.0001). Concomitant up-regulated expression of gene pathways strongly correlated with INHBA expression demonstrated further deleterious effects on survival (p<0.0148). CONCLUSION: Activin may be an important component of early carcinogenesis in OPL and HNSCC with unfavorable effects on clinical end-points such as survival.

Formulation strategies for the development of high drug-loaded amorphous solid dispersions.

Amorphous solid dispersions (ASD) have gained tremendous attention over the past two decades as one of the most promising techniques for enhancing the solubility of poorly water-soluble drugs. However, low drug loading is one of the major challenges of ASD technology that limits its commercialization to only a few drug candidates. Increasing the drug loading increases the risk of recrystallization during storage (solid state) and/or during dissolution (solution state). Various formulation and process-related strategies have been explored that open the possibility of formulating high drug-loaded ASDs without the risk of recrystallization. Here, we review various formulation approaches, such as the use of surfactants, mesoporous silicas, polymer combinations, in situ thermal crosslinking, structural modification of polymeric carriers, and surface nanocoating using minerals. We also discuss the mechanisms by which these approaches inhibit solid state and/or solution state recrystallization.

Therapeutic Intervention of Neuroinflammatory Alzheimer Disease Model by Inhibition of Classical Complement Pathway with the Use of Anti-C1r Loaded Exosomes.

Alzheimer's disease (AD) is a complex neurodegenerative disease associated with memory decline, cognitive impairment, amyloid plaque formation and tau tangles. Neuroinflammation has been shown to be a precursor to apparent amyloid plaque accumulation and subsequent synaptic loss and cognitive decline. In this study, the ability of a novel, small molecule, T-ALZ01, to inhibit neuroinflammatory processes was analyzed. T-ALZ01, an inhibitor of complement component C1r, demonstrated a significant reduction in the levels of the inflammatory cytokines, IL-6 and TNF-α in vitro. An LPS-induced animal model, whereby animals were injected intraperitoneally with 0.5 mg/kg LPS, was used to analyze the effect of T-ALZ01 on neuroinflammation in vivo. Moreover, exosomes (nanosized, endogenous extracellular vehicles) were used as drug delivery vehicles to facilitate intranasal administration of T-ALZ01 across the blood-brain barrier. T-ALZ01 demonstrated significant reduction in degenerating neurons and the activation of resident microglia and astrocytes, as well as inflammatory markers in vivo. This study demonstrates a significant use of small molecule complement inhibitors via exosome drug delivery as a possible therapeutic in disorders characterized by neuroinflammation, such AD.

Vermistabilization of mango tree pruning waste with five earthworm species: A biochemical and heavy metal assessment.

Mango tree pruning results in high biomass output, which is a serious agricultural and environmental problem. Vermicomposting is a potential, fast and sustainable tool to address these challenges. For sixty days, the experiment was carried out in six vermireactors containing five earthworm species by Eudrilus eugeniae, Eisenia fetida, Aporrectodea rosea, Lumbricus rubellus, and Lampito mauritii, as well as composting (without earthworm) using mango tree pruning waste biomass along with cattle dung as an instant preferred feeding material for earthworms. The pH, TOC, C/N and C/P ratios of the waste were substantially reduced by the earthworm activity. However, after vermicomposting, the levels of macronutrients (N, P, K, Ca, Mg, S) and micronutrients (Fe, Mn, Zn, and Cu) and microbial count substantially increased. The TOC content of waste was reduced by 42-55%, and the C/N of vermicompost ranged from 5.58 to 11.38. The results showed that earthworm fecundity was highest in vermireactors containing Eudrilus eugeniae and Eisenia fetida. The current study was ultimately determine that vermicomposting using Eudrilus eugeniae or Eisenia fetida is an effective strategy for utilising mango tree pruning waste, ensuring environmental sustainability and improving farmer revenue.