Modeling of noncovalent inhibitors of the papain-like protease (PLpro) from SARS-CoV-2 considering the protein flexibility by using molecular dynamics and cross-docking.

The papain-like protease (PLpro) found in coronaviruses that can be transmitted from animals to humans is a critical target in respiratory diseases linked to Severe Acute Respiratory Syndrome (SARS-CoV). Researchers have proposed designing PLpro inhibitors. In this study, a set of 89 compounds, including recently reported 2-phenylthiophenes with nanomolar inhibitory potency, were investigated as PLpro noncovalent inhibitors using advanced molecular modeling techniques. To develop the work with these inhibitors, multiple structures of the SARS-CoV-2 PLpro binding site were generated using a molecular sampling method. These structures were then clustered to select a group that represents the flexibility of the site. Subsequently, models of the protein-ligand complexes were created for the set of inhibitors within the chosen conformations. The quality of the complex models was assessed using LigRMSD software to verify similarities in the orientations of the congeneric series and interaction fingerprints to determine the recurrence of chemical interactions. With the multiple models constructed, a protocol was established to choose one per ligand, optimizing the correlation between the calculated docking energy values and the biological activities while incorporating the effect of the binding site's flexibility. A strong correlation (R2 = 0.922) was found when employing this flexible docking protocol.

Linking triphenylphosphonium cation to a bicyclic hydroquinone improves their antiplatelet effect via the regulation of mitochondrial function.

Platelets are the critical target for preventing and treating pathological thrombus formation. However, despite current antiplatelet therapy, cardiovascular mortality remains high, and cardiovascular events continue in prescribed patients. In this study, first results were obtained with ortho-carbonyl hydroquinones as antiplatelet agents; we found that linking triphenylphosphonium cation to a bicyclic ortho-carbonyl hydroquinone moiety by a short alkyl chain significantly improved their antiplatelet effect by affecting the mitochondrial functioning. The mechanism of action involves uncoupling OXPHOS, which leads to an increase in mitochondrial ROS production and a decrease in the mitochondrial membrane potential and OCR. This alteration disrupts the energy production by mitochondrial function necessary for the platelet activation process. These effects are responsive to the complete structure of the compounds and not to isolated parts of the compounds tested. The results obtained in this research can be used as the basis for developing new antiplatelet agents that target mitochondria.

Assessing mitochondria-targeted acyl hydroquinones on the mitochondrial platelet function and cytotoxic activity: Role of the linker length.

INTRODUCTION: The use of triphenylphosphonium cation (TPP+) linked to phenolic compounds by alkyl chains has a significant relevance as a mitochondrial delivery strategy in biomedicine because it affects mitochondrial bioenergetics in models of noncommunicable diseases such as cancer and cardiovascular-related conditions. Studies indicate that a long alkyl chain (10-12 carbon) increases the mitochondrial accumulation of TPP+-linked drugs. In contrast, other studies show that these compounds are consistently toxic to micromolar concentrations (as observed in platelets). In the present study, we evaluated the in vitro effect of three series of triphenylphosphonium-linked acyl hydroquinones derivates on the metabolism and function of human platelets using 3-9 carbons for the alkyl linker. Those were assessed to determine the role of the length of the alkyl chain linker on platelet toxicity. METHODS: Human platelets were exposed in vitro to different concentrations (2-40 µM) of every compound; cellular viability, phosphatidylserine exposition, mitochondrial membrane potential (ΔΨm), intracellular calcium release, and intracellular ROS generation were assessed by flow cytometry. An in silico energetic profile was generated with Umbrella sampling molecular dynamics (MD). RESULTS AND CONCLUSIONS: There was an increase in cytotoxic activity directly related to the length of the acyl chain and lipophilicity, as seen by three techniques, and this was consistent with a decrease in ΔΨm. The in silico energetic profiles point out that the permeability of the mitochondrial membrane may be involved in the cytotoxicity of phosphonium salts. This information may be relevant for the design of new TPP+ -based drugs with a safe cardiovascular profile.

Reversal of a Fluorescent Fluoride Chemosensor from Turn-Off to Turn-On Based on Aggregation Induced Emission Properties.

Here we present a new approach for the development of fluoride chemosensors taking advantage of aggregation induced emission (AIE) properties. Although AIE-based chemosensors have been described, they rely primarily on the analyte causing aggregation and hence fluorescence. We propose a new concept in the use of AIE for the development of fluorescent sensors. Our hypothesis is based on the fact that a turn-off chemosensor in solution can be transformed into turn-on in the solid state if the properties of ACQ and AIE are properly combined between the fluorescent molecules involved. To demonstrate this hypothesis, we have selected a fluorescent chemosensor for the fluoride anion with a conjugated structure of bis(styryl)pyrimidine that, while showing turn-off behavior in solution, becomes turn-on when it is brought to the solid state. We have also combined it with the advantages of a detection system based on the microfluidic paper-based analytical devices (µPAD). The system is fully characterized spectroscopically both in solution and in the solid state, and quantum mechanical calculations were performed to explain how the sensor works. The prepared device presents a high sensitivity, with no interference and with an LoD and LoQ that allow determination of fluoride concentrations in water 2 orders of magnitude below the maximum allowed by WHO.

Dammarane triterpenes targeting α-synuclein: biological activity and evaluation of binding sites by molecular docking.

Parkinson's disease (PD) is a neurodegenerative disorder that affects adult people whose treatment is palliative. Thus, we decided to test three dammarane triterpenes 1, 1a, 1b, and we determined that 1 and 1a inhibit ß-aggregation through thioflavine T rather than 1b. Since compound 1 was most active, we determined the interaction between α-synuclein and 1 at 50 µM (Kd) through microscale thermophoresis. Also, we observed differences in height and diameter of aggregates, and α-synuclein remains unfolded in the presence of 1. Also, aggregates treated with 1 do not provoke neurites' retraction in N2a cells previously induced by retinoic acid. Finally, we studied the potential sites of interaction between 1 with α-synuclein fibrils using molecular modelling. Docking experiments suggest that 1 preferably interact with the site 2 of α-synuclein through hydrogen bonds with residues Y39 and T44.

Transforming Non-Selective Angiotensin-Converting Enzyme Inhibitors in C- and N-domain Selective Inhibitors by Using Computational Tools.

The two-domain dipeptidylcarboxypeptidase Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in blood pressure regulation via the reninangiotensin and kallikrein-kinin systems by converting angiotensin I to the potent vasoconstrictor angiotensin II, and by cleaving a number of other substrates including the vasodilator bradykinin and the anti-inflammatory peptide N-acetyl-SDKP. Therefore, the design of ACE inhibitors is within the priorities of modern medical sciences for treating hypertension, heart failures, myocardial infarction, and other related diseases. Despite the success of ACE inhibitors for the treatment of hypertension and congestive heart failure, they have some adverse effects, which could be attenuated by selective domain inhibition. Crystal structures of both ACE domains (nACE and cACE) reported over the last decades could facilitate the rational drug design of selective inhibitors. In this review, we refer to the history of the discovery of ACE inhibitors, which has been strongly related to the development of molecular modeling methods. We stated that the design of novel selective ACE inhibitors is a challenge for current researchers which requires a thorough understanding of the structure of both ACE domains and the help of molecular modeling methodologies. Finally, we performed a theoretical design of potential selective derivatives of trandolaprilat, a drug approved to treat critical conditions of hypertension, to illustrate how to use molecular modeling methods such as de novo design, docking, Molecular Dynamics (MD) simulations, and free energy calculations for creating novel potential drugs with specific interactions inside nACE and cACE binding sites.

Combining sun-based technologies (microalgae and solar disinfection) for urban wastewater regeneration.

Solar disinfection (SODIS) of urban wastewater can be a suitable technology for improving the microbiological quality of reclaimed water as a complement to other extensive and environmentally friendly technologies such as microalgae biotreatment. The objective of this work is to evaluate the feasibility of incorporating the SODIS technology at the end of a pilot scale urban wastewater treatment plant (WWTP) where the processes are based on microalgae biotechnology and comprising three Upflow Anaerobic Sludge Blanket (UASB, 20m3 each one) reactor, six High Rate Algal Ponds (HRAP, 32m2 each one), and a Dissolved Air Flotation (DAF, 1m3) unit. E. coli concentration was monitored at the effluent of the different units (UASB, HRAP, DAF) of the pilot WWTP. The efficiency of the SODIS process was studied for the inactivation of three of the commonly employed indicator microorganisms (Escherichia coli, Enterococcus spp. and Clostridium perfringens) using a compound parabolic collector (CPC) for five months under various conditions of irradiance and temperature. E. coli and Enterococcus spp. were more effectively disinfected by the SODIS unit (2.9 and 2.5 logarithms of reduction on average, respectively) than by the HRAP (2 and 1.1) or the DAF (0.9 and 0.1). On the contrary, the DAF technology achieved better reduction rates of C. perfringens (1.7) than the SODIS (0.9) and the HRAP (0.1). No regrowth of any microorganisms was detected during dark storage after the SODIS treatment. Incorporating a SODIS unit after the non-conventional WWTP processes substantially increases the possibilities for reuse of the treated water after receiving a cumulative UV radiation dose of 25W·h/m2 (50min of normalized time of solar illumination). The surface requirement of the SODIS equipment would be 3.5 times smaller than the HRAP's surface.

Relationship between ghrelin and the metabolic syndrome in the elderly: a longitudinal population-based study.

CONTEXT: Ghrelin regulates energy homeostasis and may contribute to the development of the metabolic syndrome (MS) in the elderly. OBJECTIVE: To study the relationship between ghrelin and the MS, IGF-I and life style factors over a 2-year follow-up. DESIGN: Longitudinal population-based study, starting from 2002; 2 years follow-up. PARTICIPANTS: Three hundred and thirteen (153 men/160 women) individuals living independently older than 70 years. RESULTS: MS was found in 54.9% of men and 61% of women. In the 229 subjects available at follow-up, ghrelin was higher in men than in women at basal (P = 0.002) and 2-year follow-up (P = 0.004). Ghrelin decreased over time in both genders (P < 0.01). Ghrelin was lower in individuals showing MS compared to non-MS (P = 0.08), but this difference was more evident at 2-year follow-up (P = 0.016), mostly due to men with MS (P = 0.002) and even after adjustment for BMI, gender and age. Individuals with MS had an OR of 1.67 (95% CI: 1.0-2.78) for low ghrelin (< first tertile); when adjusting by BMI, gender and age, only high triglycerides with OR 1.8 (1.0-3.3), remained statistically significant among the MS components. IGF-I showed a positive correlation with ghrelin only in individuals without MS (r(s) 0.403, P < 0.001) with no gender differences; this relationship was not found in MS (r(s) 0.120, P = 0.129). A positive association of ghrelin was found with academic level, alcohol consumption and smoking. CONCLUSIONS: Ghrelin is higher in old men in comparison to women and decreases over time with a steeper decline in subjects with MS; moreover, in these subjects ghrelin/IGF-I correlation is lost.

Ecological control of Triatoma dimidiata (Latreille, 1811): five years after a Costa Rican pilot project.

An ecological pilot project for the control of Triatoma dimidiata allowed a new evaluation four and five years after environmental modifications in the peridomestic areas of 20 households. It was verified that the two groups of houses, 10 case-houses and 10 control-houses, were free of insects after those periods of time. In the first group, the owners started a chicken coop in the backyard and a colony of bugs was found there without infesting the house. In the second group, the inhabitants of one house once again facilitated the conditions for the bugs to thrive in the same store room, reaffirming that man-made ecotopes facilitates colonization. This ecological control method was revealed to be reliable and sustainable and it is recommended to be applied to those situations where the vectors of Chagas disease can colonize houses and are frequent in wild ecotopes.

Ecological control of Triatoma dimidiata (Latreille, 1811): five years after a Costa Rican pilot project

An ecological pilot project for the control of Triatoma dimidiata allowed a new evaluation four and five years after environmental modifications in the peridomestic areas of 20 households. It was verified that the two groups of houses, 10 case-houses and 10 control-houses, were free of insects after those periods of time. In the first group, the owners started a chicken coop in the backyard and a colony of bugs was found there without infesting the house. In the second group, the inhabitants of one house once again facilitated the conditions for the bugs to thrive in the same store room, reaffirming that man-made ecotopes facilitates colonization. This ecological control method was revealed to be reliable and sustainable and it is recommended to be applied to those situations where the vectors of Chagas disease can colonize houses and are frequent in wild ecotopes.

[Metabolic syndrome and cardiovascular disease in elders: results of the Mataró Ageing study]. / Síndrome metabólico y enfermedad cardiovascular en ancianos: resultados del Estudio de Envejecimiento de Mataró

BACKGROUND AND OBJECTIVE: The metabolic syndrome (MS) is a constellation of factors apparently associated to an increased cardiovascular risk, and with a reported increasing prevalence in parallel with aging process. The aim of this study was to assess the prevalence of MS in elder subjects according to the criteria of the National Education Program (ATP-III) and the International Diabetes Federation (IDF). SUBJECTS AND METHOD: Population-based cross-sectional study including 313 individuals (153 men and 160 women) older than 70 years. The prevalence of MS was evaluated according to both definitions and its association with cardiovascular disease (CD) was investigated. RESULTS: MS was observed in 50.2% of subjects according to ATP-III (41.5% of men and 58.6% of women; p = 0.004) and in 57.9% when using IDF criteria (54.9% of men and 61% of women; p = 0.29). Prevalence differences were observed between ATP-III and IDF only in men. No differences were found in the frequencies of the different components of the MS for the 2 definitions, neither for tobacco consumption, ethanol intake and educational level. There was no differences in the coexistence of CD in relation the presence or absence of MS, no matter the definition used; also, no special association with CD was found for any of the individual components of the MS. CONCLUSIONS: Among a representative population sample of old people living in a Mediterranean community, despite a very high frequency of MS, there was no excess prevalence of CD in those identified as having MS.

Hormonal determinants of depression and cognitive function in independently-living elders.

OBJECTIVE: To study the potential associations among circulating insulinlike growth factor 1 (IGF-1) and adrenal and gonadal steroids with cognitive status and depression in a group of independently-living elders. DESIGN: Population-based cross sectional study. METHODS: A total of 313 individuals (160 women and 153 men, with a mean age of 76.7±7 years) participated in this study. A physical examination, assessment of functional capacity, cognitive function, depression, educational level and measurement of plasma cortisol, dehydroepiandrosterone (DHEA) and its sulphate (DHEAs), testosterone, estradiol, and IGF-1 were performed. RESULTS: In women, adrenal steroids showed a negative correlation with global cognition (ß=-0.79; p=0.03 for DHEA and ß=-0.27; p=0.002 for cortisol). A positive correlation with IGF-1 (ß=0.026; p=0.04) was found for cognition in women after adjustment for depression. For memory function, DHEA correlated negatively but no relationship with IGF-1 and cortisol was observed. No relationships with cognition were observed in men for any of the steroids or other hormones studied. Educational level showed the highest protective effect (odds ratio [OR] = 6.25) for preserved cognition for both sexes; in women, OR for deteriorated cognition with age, DHEA and cortisol were 1.14, 1.57 and 1.09, respectively. No associations between depression and hormonal profile were found in either sex. CONCLUSIONS: Educational level was positively associated with cognitive function in independently-living elderly men and women, while adrenal steroids were associated with impaired cognition in elderly women but not in men. The hormonal milieu seemed to have little or no influence on depression in the men and women studied.

The finding of Rhodnius pallescens Barber, 1932 (Reduviidae: Triatominae) in palm trees (Attalea butyracea ) in north Costa Rica

A total of 167 nymphs and adults of Rhodnius pallescens was collected from the basal parts of dead fronds of two palm trees (Attalea butyracea ) in the town of Los Chiles, province of Alajuela, Costa Rica, close to the Nicaraguan border. Previous records of this species in the same habitat come from Panama and Colombia. A group of 32 insects examined for Trypanosoma cruzi revealed that all were infected. By examining their hemolymph, none of 24 of the insects was found infected with T. rangeli. Balb/c mice inoculated with the T. cruzi strain from infected insects showed a typical acute myocarditis reaction with numerous groups of parasites among the heart bers at autopsy. The geographical distribution of R. pallescens as well as its possible presence in other Central American countries and in Mexico where it is still unknown, coinciding with the distribution of the same species of palm tree, is discussed. Likewise, the potential of R. pallescens in becoming adapted to domestic environments is analyzed in light of recent information, and the epidemiological implications of the phenomenon are also discussed.