Illuminating a Solvent-Dependent Hierarchy for Aromatic CH/π Complexes with Dynamic Covalent Glyco-Balances.

CH/π interactions are prevalent among aromatic complexes and represent invaluable tools for stabilizing well-defined molecular architectures. Their energy contributions are exceptionally sensitive to various structural and environmental factors, resulting in a context-dependent nature that has led to conflicting findings in the scientific literature. Consequently, a universally accepted hierarchy for aromatic CH/π interactions has remained elusive. Herein, we present a comprehensive experimental investigation of aromatic CH/π complexes, employing a novel approach that involves isotopically labeled glyco-balances generated in situ. This innovative strategy not only allows us to uncover thermodynamic insights but also delves into the often less-accessible domain of kinetic information. Our analyses have yielded more than 180 new free energy values while considering key factors such as solvent properties, the interaction geometry, and the presence and nature of accompanying counterions. Remarkably, the obtained results challenge conventional wisdom regarding the stability order of common aromatic complexes. While it was believed that cationic CH/π interactions held the highest strength, followed by polarized CH/π, nonpolarized CH/π, and finally anionic CH/π interactions, our study reveals that this hierarchy can be subverted depending on the environment. Indeed, the performance of polarized CH/π interactions can match or even outcompete that of cationic CH/π interactions making them a more reliable stabilization strategy across the entire spectrum of solvent polarity. Overall, our results provide valuable guidelines for the selection of optimal interacting partners in every chemical environment, allowing the design of tailored aromatic complexes with applications in supramolecular chemistry, organocatalysis, and/or material sciences.

Ligand-Directed Chemistry on Glycoside Hydrolases - A Proof of Concept Study.

Selective covalent labelling of enzymes using small molecule probes has advanced the scopes of protein profiling. The covalent bond formation to a specific target is the key step of activity-based protein profiling (ABPP), a method which has become an indispensable tool for measuring enzyme activity in complex matrices. With respect to carbohydrate processing enzymes, strategies for ABPP so far involve labelling the active site of the enzyme, which results in permanent loss of activity. Here, we report in a proof of concept study the use of ligand-directed chemistry (LDC) for labelling glycoside hydrolases near - but not in - the active site. During the labelling process, the competitive inhibitor is cleaved from the probe, departs the active site and the enzyme maintains its catalytic activity. To this end, we designed a building block synthetic concept for small molecule probes containing iminosugar-based reversible inhibitors for labelling of two model ß-glucosidases. The results indicate that the LDC approach can be adaptable for covalent proximity labelling of glycoside hydrolases.

Suspensión alta al ligamento uterosacro con suturas permanentes en el prolapso apical: seguimiento a 24 meses / High suspension to the uterosacral ligament with permanent sutures in the apical prolapse: 24-month follow-up

Introducción: El prolapso de órganos pélvico (POP) es una patología frecuente que afecta hasta el 60% de las mujeres. La fijación alta al ligamento uterosacro (FAUS) transvaginal es una alternativa para el tratamiento del prolapso apical con buenos resultados, tiempos operatorios y de recuperación acotados, además de bajas tasas de complicaciones. Objetivo: Evaluar la tasa de éxito anatómico y subjetivo en pacientes portadoras de un prolapso apical sometidas a FAUS en el Hospital de Quilpué a 24 meses de seguimiento. Materiales y método: Se realizó un estudio retrospectivo observacional descriptivo, seleccionando a todas las pacientes sintomáticas con un prolapso apical ≥ 2 de la clasificación de POP-Q, sometidas a una FAUS entre septiembre de 2014 y octubre de 2019. Los datos fueron obtenidos desde la base de datos de la unidad de uroginecología del Hospital de Quilpué, previa aprobación del comité de ética. El éxito objetivo se definió como un punto C a 1 centímetro sobre el himen y el éxito subjetivo con una escala de impresión de mejora global del paciente (PGI-I) mejor o mucho mejor y/o una escala visual analógica (EVA) mayor al 80%, a 24 meses de seguimiento. Resultados: Se incluyeron 46 pacientes. La tasa de éxito objetivo fue del 84% y de éxito subjetivo del 70%. Conclusiones: La FAUS transvaginal con suturas permanentes es una excelente alternativa para el tratamiento del prolapso apical con una tasa de éxito similar al gold standard a 24 meses de seguimiento.

Introduction: Pelvic organ prolapse (POP) is a frequent pathology that affects up to 60% of women. Transvaginal uterosacral ligament high fixation (USLs: utero-sacral ligaments) is an alternative for the treatment of apical prolapse with good results, limited operative and recovery times, as well as low rates of complications. Objective: To evaluate the anatomical and subjective success rate in patients with an apical prolapse undergoing STALUS at the Quilpué Hospital at 24 months of follow-up. Materials and method: A descriptive observational retrospective study was carried out, selecting all symptomatic patients with an apical prolapse ≥ 2 of the POP Q classification, submitted to a FAUS between September 2014 and October 2019. The data were obtained from the database of the Urogynecology Unit of the Quilpué Hospital, prior approval of the ethics committee. Objective success was defined as a C-point 1 centimeter above the hymen and subjective success with better or much better Patient Global Impression-Improvement (PGI-I) scale and/or a greater than 80% Visual Analogue Scale (VAS), at 24 months of follow-up. Results: 46 patients were included. The objective success rate was 84% and the subjective success rate was 70%. Conclusions: The transvaginal FAUS with permanent sutures is an excellent alternative for the treatment of apical prolapse with a success rate similar to the gold standard at 24 months of follow-up.

Perceived Impact of the COVID-19 Pandemic on Physical Activity Among Adult Patients With Rheumatologic Disease.

OBJECTIVE: The objective of this cross-sectional study was to investigate the impact of the COVID-19 pandemic on physical activity (PA) levels of patients with rheumatic and musculoskeletal diseases (RMDs) and to examine factors associated with decreased PA. METHODS: A sample of adult patients with RMDs (n = 7,776) was identified through electronic medical records from an academic health care system in North Carolina. Invitations to participate in an online survey were sent between July 2020 and September 2020 to assess self-reported changes in PA during the COVID-19 pandemic. Descriptive statistics, age-adjusted prevalence odds ratios (PORs), and 95% confidence intervals (CIs) were computed to examine patient characteristics associated with decreased PA. RESULTS: A total of 893 eligible participants completed the survey (mean age 57.8 ± 14.9 years, 75.8% female). The most common primary diagnoses reported among participants included rheumatoid arthritis (27.3%), osteoarthritis (16.0%), and systemic lupus erythematosus (SLE) (13.0%). More than half of participants (56.8%) reported engaging in less PA since the pandemic began. Factors associated with engaging in less PA included lower self-reported general health (POR, 2.21; CI, 1.64-2.97) and a diagnosis of SLE (POR, 1.57; CI, 1.03-2.38). Comorbidities associated with decreased PA included chronic pain (POR, 1.38; CI, 1.04-1.82), depression (POR, 1.48; CI, 1.09-2.01), and hypertension (POR, 1.44; CI, 1.10-1.90). CONCLUSION: The COVID-19 pandemic has exacerbated barriers to PA in patients with RMDs. There is a critical need to provide resources, support, and multifaceted programs to encourage PA in patients with RMDs during the COVID-19 pandemic.

Pharmacological Chaperones for GCase that Switch Conformation with pH Enhance Enzyme Levels in Gaucher Animal Models.

Gaucher disease is a lysosomal storage disorder caused by mutations which destabilize the native folded form of GCase, triggering degradation and ultimately resulting in low enzyme activity. Pharmacological chaperones (PCs) which stabilize mutant GCase have been used to increase lysosomal activity through improving trafficking efficiency. By engineering their inherent basicity, we have synthesized PCs that change conformation between the ER and the lysosomal environment, thus weakening binding to GCase after its successful trafficking to the lysosome. NMR studies confirmed the conformational change while X-ray data reveal bound conformations and binding modes. These results were further corroborated by cell studies showing increases in GCase activity when using the pH-switchable probe at low dosing. Preliminary in vivo assays with humanized mouse models of Gaucher showed enhanced GCase activity levels in relevant tissues, including the brain, further supporting their potential.

Glycosylation of Epigallocatechin Gallate by Engineered Glycoside Hydrolases from Talaromyces amestolkiae: Potential Antiproliferative and Neuroprotective Effect of These Molecules.

Glycoside hydrolases (GHs) are enzymes that hydrolyze glycosidic bonds, but some of them can also catalyze the synthesis of glycosides by transglycosylation. However, the yields of this reaction are generally low since the glycosides formed end up being hydrolyzed by these same enzymes. For this reason, mutagenic variants with null or drastically reduced hydrolytic activity have been developed, thus enhancing their synthetic ability. Two mutagenic variants, a glycosynthase engineered from a ß-glucosidase (BGL-1-E521G) and a thioglycoligase from a ß-xylosidase (BxTW1-E495A), both from the ascomycete Talaromyces amestolkiae, were used to synthesize three novel epigallocatechin gallate (EGCG) glycosides. EGCG is a phenolic compound from green tea known for its antioxidant effects and therapeutic benefits, whose glycosylation could increase its bioavailability and improve its bioactive properties. The glycosynthase BGL-1-E521G produced a ß-glucoside and a ß-sophoroside of EGCG, while the thioglycoligase BxTW1-E495A formed the ß-xyloside of EGCG. Glycosylation occurred in the 5″ and 4″ positions of EGCG, respectively. In this work, the reaction conditions for glycosides' production were optimized, achieving around 90% conversion of EGCG with BGL-1-E521G and 60% with BxTW1-E495A. The glycosylation of EGCG caused a slight loss of its antioxidant capacity but notably increased its solubility (between 23 and 44 times) and, in the case of glucoside, also improved its thermal stability. All three glycosides showed better antiproliferative properties on breast adenocarcinoma cell line MDA-MB-231 than EGCG, and the glucosylated and sophorylated derivatives induced higher neuroprotection, increasing the viability of SH-S5Y5 neurons exposed to okadaic acid.

A Fungal Versatile GH10 Endoxylanase and Its Glycosynthase Variant: Synthesis of Xylooligosaccharides and Glycosides of Bioactive Phenolic Compounds.

The study of endoxylanases as catalysts to valorize hemicellulosic residues and to obtain glycosides with improved properties is a topic of great industrial interest. In this work, a GH10 ß-1,4-endoxylanase (XynSOS), from the ascomycetous fungus Talaromyces amestolkiae, has been heterologously produced in Pichia pastoris, purified, and characterized. rXynSOS is a highly glycosylated monomeric enzyme of 53 kDa that contains a functional CBM1 domain and shows its optimal activity on azurine cross-linked (AZCL)-beechwood xylan at 70 °C and pH 5. Substrate specificity and kinetic studies confirmed its versatility and high affinity for beechwood xylan and wheat arabinoxylan. Moreover, rXynSOS was capable of transglycosylating phenolic compounds, although with low efficiencies. For expanding its synthetic capacity, a glycosynthase variant of rXynSOS was developed by directed mutagenesis, replacing its nucleophile catalytic residue E236 by a glycine (rXynSOS-E236G). This novel glycosynthase was able to synthesize ß-1,4-xylooligosaccharides (XOS) of different lengths (four, six, eight, and ten xylose units), which are known to be emerging prebiotics. rXynSOS-E236G was also much more active than the native enzyme in the glycosylation of a broad range of phenolic compounds with antioxidant properties. The interesting capabilities of rXynSOS and its glycosynthase variant make them promising tools for biotechnological applications.

Aromatic Interactions in Glycochemistry: From Molecular Recognition to Catalysis.

Aromatic platforms are ubiquitous recognition motifs occurring in protein carbohydrate- binding domains (CBDs), RNA receptors and enzymes. They stabilize the glycoside/ receptor complexes by participating in stacking CH/π interactions with either the α- or ß- face of the corresponding pyranose units. In addition, the role played by aromatic units in the stabilization of glycoside cationic transition states has started being recognized in recent years. Extensive studies carried out during the last decade have allowed the dissection of the main contributing forces that stabilize the carbohydrate/aromatic complexes, while helping delineate not only the standing relationship between the glycoside/ aromatic chemical structures and the strength of this interaction but also their potential influence on glycoside reactivity.

Binding-driven reactivity attenuation enables NMR identification of selective drug candidates for nucleic acid targets.

NMR methods, and in particular ligand-based approaches, are among the most robust and reliable alternatives for binding detection and consequently, they have become highly popular in the context of hit identification and drug discovery. However, when dealing with DNA/RNA targets, these techniques face limitations that have precluded widespread application in medicinal chemistry. In order to expand the arsenal of spectroscopic tools for binding detection and to overcome the existing difficulties, herein we explore the scope and limitations of a strategy that makes use of a binding indicator previously unexploited by NMR: the perturbation of the ligand reactivity caused by complex formation. The obtained results indicate that ligand reactivity can be utilised to reveal association processes and identify the best binders within mixtures of significant complexity, providing a conceptually different reactivity-based alternative within NMR screening methods.

Synthesis and Characterization of a Novel Resveratrol Xylobioside Obtained Using a Mutagenic Variant of a GH10 Endoxylanase.

Resveratrol is a natural polyphenol with antioxidant activity and numerous health benefits. However, in vivo application of this compound is still a challenge due to its poor aqueous solubility and rapid metabolism, which leads to an extremely low bioavailability in the target tissues. In this work, rXynSOS-E236G glycosynthase, designed from a GH10 endoxylanase of the fungus Talaromyces amestolkiae, was used to glycosylate resveratrol by using xylobiosyl-fluoride as a sugar donor. The major product from this reaction was identified by NMR as 3-O-ꞵ-d-xylobiosyl resveratrol, together with other glycosides produced in a lower amount as 4'-O-ꞵ-d-xylobiosyl resveratrol and 3-O-ꞵ-d-xylotetraosyl resveratrol. The application of response surface methodology made it possible to optimize the reaction, producing 35% of 3-O-ꞵ-d-xylobiosyl resveratrol. Since other minor glycosides are obtained in addition to this compound, the transformation of the phenolic substrate amounted to 70%. Xylobiosylation decreased the antioxidant capacity of resveratrol by 2.21-fold, but, in return, produced a staggering 4,866-fold improvement in solubility, facilitating the delivery of large amounts of the molecule and its transit to the colon. A preliminary study has also shown that the colonic microbiota is capable of releasing resveratrol from 3-O-ꞵ-d-xylobiosyl resveratrol. These results support the potential of mutagenic variants of glycosyl hydrolases to synthesize highly soluble resveratrol glycosides, which could, in turn, improve the bioavailability and bioactive properties of this polyphenol.

Lipid-mimicking phosphorus-based glycosidase inactivators as pharmacological chaperones for the treatment of Gaucher's disease.

Gaucher's disease, the most prevalent lysosomal storage disorder, is caused by missense mutation of the GBA gene, ultimately resulting in deficient GCase activity, hence the excessive build-up of cellular glucosylceramide. Among different therapeutic strategies, pharmacological chaperoning of mutant GCase represents an attractive approach that relies on small organic molecules acting as protein stabilizers. Herein, we expand upon a new class of transient GCase inactivators based on a reactive 2-deoxy-2-fluoro-ß-d-glucoside tethered to an array of lipid-mimicking phosphorus-based aglycones, which not only improve the selectivity and inactivation efficiency, but also the stability of these compounds in aqueous media. This hypothesis was further validated with kinetic and cellular studies confirming restoration of catalytic activity in Gaucher cells after treatment with these pharmacological chaperones.

Intramolecular Metal-Free C(sp3)-H Activation Enables a Selective Mono O-Debenzylation of Fully Protected Aminosugars.

Carbamate-bearing benzylated aminosugars undergo an I2/I(III)-promoted intramolecular hydrogen atom transfer (IHAT) followed by a nucleophilic attack to provide polycyclic structures. Thus, suitably positioned benzyl ethers are surgically oxidized into the corresponding mixed N/O-benzylidene acetals, which can be conveniently deprotected under mild acidic conditions to grant access to selectively O-deprotected aminosugars amenable for further derivatization. The scope of this strategy has been proven with a series of furanosic and pyranosic scaffolds. Preliminary mechanistic studies, including Hammett LFER and KIE analyses, support a reaction pathway with nucleophilic cyclization as the rate-determining step.

Pilot study of an internet-based pain coping skills training program for patients with systemic Lupus Erythematosus.

BACKGROUND: Patients with Systemic Lupus Erythematosus (SLE) often experience pain and other symptoms that negatively impact quality of life. Interventions that enhance the use of behavioral and cognitive coping strategies may lead to improved outcomes among patients with SLE. Pain coping skills training (PCST) programs have been shown to improve outcomes among patients with other rheumatic conditions, but there have been no trials of PCST among patients with SLE. This study was a preliminary assessment of the feasibility and efficacy of painTRAINER, an automated, internet-based PCST program, among patients with SLE. METHODS: Participants (n = 60) with SLE from one health care system were randomly assigned with equal allocation to painTRAINER or a wait list control group. PainTRAINER involves 8 modules; participants were instructed to complete one module weekly, along with practice activities for each cognitive or behavioral coping skill. Outcome measures were assessed at baseline and 9-week follow-up, including the Pain Catastrophizing Scale, PROMIS Subscales (Pain Interference, Physical Function, Sleep Disturbance, Anxiety, Depression, Fatigue and Participation), and the LupusPRO questionnaire. Mean changes in outcomes from baseline to follow up and Cohen's d effect sizes were computed. RESULTS: Effect sizes for the painTRAINER group (relative to the wait list group) were small, with changes being greatest for the PROMIS Depression score (d = - 0.32). Among those randomized to the painTRAINER group, 50% accessed the program ("painTRAINER users"). Most of those who did not access the program stated that they did not receive instructions via email. Effect sizes for "painTRAINER users" (relative to wait list) were larger than for the whole painTRAINER group: Pain Catastrophizing d = - 0.60, PROMIS Pain Interference d = - 0.3., PROMIS Depression d = - 0.44, LupusPRO Health-Related Quality of Life d = 0.30. CONCLUSIONS: PainTRAINER users reported meaningful improvements in multiple physical and psychological outcomes, supporting the potential of PCST programs to benefit individuals with SLE. However, strategies are needed to improve engagement with the program and tailor content to comprehensively address key SLE symptoms and challenges. TRIAL REGISTRATION: NCT03933839 , May 1, 2019.

De Novo Design of Selective Quadruplex-Duplex Junction Ligands and Structural Characterisation of Their Binding Mode: Targeting the G4 Hot-Spot.

Invited for the cover of this issue are Andrés G. Santana, Carlos González, Juan Luis Asensio and co-workers at Instituto de Química Orgánica General, Instituto de Química-Física Rocasolano and Universidad de La Rioja. The image depicts drug selectivity using a metaphor of an arrow hitting a target. Read the full text of the article at 10.1002/chem.202005026.

De Novo Design of Selective Quadruplex-Duplex Junction Ligands and Structural Characterisation of Their Binding Mode: Targeting the G4 Hot-Spot.

Targeting the interface between DNA quadruplex and duplex regions by small molecules holds significant promise in both therapeutics and nanotechnology. Herein, a new pharmacophore is reported, which selectively binds with high affinity to quadruplex-duplex junctions, while presenting a poorer affinity for G-quadruplex or duplex DNA alone. Ligands complying with the reported pharmacophore exhibit a significant affinity and selectivity for quadruplex-duplex junctions, including the one observed in the HIV-1 LTR-III sequence. The structure of the complex between a quadruplex-duplex junction with a ligand of this family has been determined by NMR methods. According to these data, the remarkable selectivity of this structural motif for quadruplex-duplex junctions is achieved through an unprecedented interaction mode so far unexploited in medicinal and biological chemistry: the insertion of a benzylic ammonium moiety into the centre of the partially exposed G-tetrad at the interface with the duplex. Further decoration of the described scaffolds with additional fragments opens up the road to the development of selective ligands for G-quadruplex-forming regions of the genome.

Single-Step Glycosylations with 13 C-Labelled Sulfoxide Donors: A Low-Temperature NMR Cartography of the Distinguishing Mechanistic Intermediates.

Glycosyl sulfoxides have gained recognition in the total synthesis of complex oligosaccharides and as model substrates for dissecting the mechanisms involved. Reactions of these donors are usually performed under pre-activation conditions, but an experimentally more convenient single-step protocol has also been reported, whereby activation is performed in the presence of the acceptor alcohol; yet, the nature and prevalence of the reaction intermediates formed in this more complex scenario have comparatively received minimal attention. Herein, a systematic NMR-based study employing both 13 C-labelled and unlabelled glycosyl sulfoxide donors for the detection and monitoring of marginally populated intermediates is reported. The results conclusively show that glycosyl triflates play a key role in these glycosylations despite the presence of the acceptor alcohol. Importantly, the formation of covalent donor/acceptor sulfonium adducts was identified as the main competing reaction, and thus a non-productive consumption of the acceptor that could limit the reaction yield was revealed.

Tandem Radical Fragmentation/Cyclization of Guanidinylated Monosaccharides Grants Access to Medium-Sized Polyhydroxylated Heterocycles.

The fragmentation of anomeric alkoxyl radicals (ARF) and the subsequent cyclization promoted by hypervalent iodine provide an excellent method for the synthesis of guanidino-sugars. The methodology described herein is one of the few existing general methodologies for the formation of medium-sized exo- and endoguanidine-containing heterocycles presenting a high degree of oxygenation in their structure.

Mechanistic Insights into the Chaperoning of Human Lysosomal-Galactosidase Activity: Highly Functionalized Aminocyclopentanes and C-5a-Substituted Derivatives of 4-epi-Isofagomine.

Glycosidase inhibitors have shown great potential as pharmacological chaperones for lysosomal storage diseases. In light of this, a series of new cyclopentanoid ß-galactosidase inhibitors were prepared and their inhibitory and pharmacological chaperoning activities determined and compared with those of lipophilic analogs of the potent ß-d-galactosidase inhibitor 4-epi-isofagomine. Structure-activity relationships were investigated by X-ray crystallography as well as by alterations in the cyclopentane moiety such as deoxygenation and replacement by fluorine of a "strategic" hydroxyl group. New compounds have revealed highly promising activities with a range of ß-galactosidase-compromised human cell lines and may serve as leads towards new pharmacological chaperones for GM1-gangliosidosis and Morquio B disease.

Thioglycoligase derived from fungal GH3 ß-xylosidase is a multi-glycoligase with broad acceptor tolerance.

The synthesis of customized glycoconjugates constitutes a major goal for biocatalysis. To this end, engineered glycosidases have received great attention and, among them, thioglycoligases have proved useful to connect carbohydrates to non-sugar acceptors. However, hitherto the scope of these biocatalysts was considered limited to strong nucleophilic acceptors. Based on the particularities of the GH3 glycosidase family active site, we hypothesized that converting a suitable member into a thioglycoligase could boost the acceptor range. Herein we show the engineering of an acidophilic fungal ß-xylosidase into a thioglycoligase with broad acceptor promiscuity. The mutant enzyme displays the ability to form O-, N-, S- and Se- glycosides together with sugar esters and phosphoesters with conversion yields from moderate to high. Analyses also indicate that the pKa of the target compound was the main factor to determine its suitability as glycosylation acceptor. These results expand on the glycoconjugate portfolio attainable through biocatalysis.

Political and affective polarisation in a democracy in crisis: The E-Dem panel survey dataset (Spain, 2018-2019).

The E-DEM dataset provides information on the evolution of political and affective polarisation and electoral behaviour in the aftermath of the political crisis that shook the Spanish party system starting in 2014. The dataset is formed by a four-wave online panel survey of the Spanish voting age population between late October 2018 and May 2019. The four waves coincide with key moments in Spanish political life including local, regional, national, and European elections, as well as the conviction of Catalan secessionist leaders. It also covers the six-month period of the surge of Spain's new radical right party, Vox, spanning from shortly before its first major electoral success in Spain's most populous region, Andalusia, to its consolidation in the May 2019 European elections. The sample, which reflects the general population in terms of age, gender, and geographical province, consists of 1,484 panellists who completed the four waves, while the samples for individual waves are larger, ranging from 1,659 to 2,501 respondents. The data is especially useful for researchers who wish to explore dynamics of ideological and affective polarisation, factors that explain the rise of new parties, and for those investigating the evolution of political attitudes in general.