SARS-CoV-2 S Mutations: A Lesson from the Viral World to Understand How Human Furin Works.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the etiological agent responsible for the worldwide pandemic and has now claimed millions of lives. The virus combines several unusual characteristics and an extraordinary ability to spread among humans. In particular, the dependence of the maturation of the envelope glycoprotein S from Furin enables the invasion and replication of the virus virtually within the entire body, since this cellular protease is ubiquitously expressed. Here, we analyzed the naturally occurring variation of the amino acids sequence around the cleavage site of S. We found that the virus grossly mutates preferentially at P positions, resulting in single residue replacements that associate with gain-of-function phenotypes in specific conditions. Interestingly, some combinations of amino acids are absent, despite the evidence supporting some cleavability of the respective synthetic surrogates. In any case, the polybasic signature is maintained and, as a consequence, Furin dependence is preserved. Thus, no escape variants to Furin are observed in the population. Overall, the SARS-CoV-2 system per se represents an outstanding example of the evolution of substrate-enzyme interaction, demonstrating a fast-tracked optimization of a protein stretch towards the Furin catalytic pocket. Ultimately, these data disclose important information for the development of drugs targeting Furin and Furin-dependent pathogens.

Development of Two-Layer Hybrid Scaffolds Based on Oxidized Polyvinyl Alcohol and Bioactivated Chitosan Sponges for Tissue Engineering Purposes.

Oxidized polyvinyl alcohol (OxPVA) is a new polymer for the fabrication of nerve conduits (NCs). Looking for OxPVA device optimization and coupling it with a natural sheath may boost bioactivity. Thus, OxPVA/chitosan sponges (ChS) as hybrid scaffolds were investigated to predict in the vivo behaviour of two-layered NCs. To encourage interaction with cells, ChS were functionalized with the self-assembling-peptide (SAP) EAK, without/with the laminin-derived sequences -IKVAV/-YIGSR. Thus, ChS and the hybrid scaffolds were characterized for mechanical properties, ultrastructure (Scanning Electron Microscopy, SEM), bioactivity, and biocompatibility. Regarding mechanical analysis, the peptide-free ChS showed the highest values of compressive modulus and maximum stress. However, among +EAK groups, ChS+EAK showed a significantly higher maximum stress than that found for ChS+EAK-IKVAV and ChS+EAK-YIGSR. Considering ultrastructure, microporous interconnections were tighter in both the OxPVA/ChS and +EAK groups than in the others; all the scaffolds induced SH-SY5Y cells' adhesion/proliferation, with significant differences from day 7 and a higher total cell number for OxPVA/ChS+EAK scaffolds, in accordance with SEM. The scaffolds elicited only a slight inflammation after 14 days of subcutaneous implantation in Balb/c mice, proving biocompatibility. ChS porosity, EAK 3D features and neuro-friendly attitude (shared with IKVAV/YIGSR motifs) may confer to OxPVA certain bioactivity, laying the basis for future appealing NCs.

Proteolytically Resistant Bioactive Peptide-Grafted Sr/Mg-Doped Hardystonite Foams: Comparison of Two Covalent Functionalization Strategies.

Hardystonite-based (HT) bioceramic foams were easily obtained via thermal treatment of silicone resins and reactive oxide fillers in air. By using a commercial silicone, incorporating strontium oxide and magnesium oxide precursors (as well as CaO and ZnO), and treating it at 1100 °C, a complex solid solution (Ca1.4Sr0.6Zn0.85Mg0.15Si2O7) that has superior biocompatibility and bioactivity properties compared to pure hardystonite (Ca2ZnSi2O7) can be obtained. Proteolytic-resistant adhesive peptide mapped on vitronectin (D2HVP), was selectively grafted to Sr/Mg-doped HT foams using two different strategies. Unfortunately, the first method (via protected peptide) was unsuitable for acid-sensitive materials such as Sr/Mg-doped HT, resulting in the release of cytotoxic levels of Zinc over time, with consequent negative cellular response. To overcome this unexpected result, a novel functionalization strategy requiring aqueous solution and mild conditions was designed. Sr/Mg-doped HT functionalized with this second strategy (via aldehyde peptide) showed a dramatic increase in human osteoblast proliferation at 6 days compared to only silanized or non-functionalized samples. Furthermore, we demonstrated that the functionalization treatment does not induce any cytotoxicity. Functionalized foams enhanced mRNA-specific transcript levels coding IBSP, VTN, RUNX2, and SPP1 at 2 days post-seeding. In conclusion, the second functionalization strategy proved to be appropriate for this specific biomaterial and was effective at enhancing the material's bioactivity.

Chemical and Mechanical Characterization of Unprecedented Transparent Epoxy-Nanomica Composites-New Model Insights for Mechanical Properties.

Two nanomicas of similar composition, containing muscovite and quartz, but with different particle size distributions, have been used to prepare transparent epoxy nanocomposites. Their homogeneous dispersion, due to the nano-size, was achieved even without being organically modified, and no aggregation of the nanoparticles was observed, thus maximizing the specific interface between matrix and nanofiller. No exfoliation or intercalation has been observed by XRD, despite the significant dispersion of the filler in the matrix which produced nanocomposites with a loss in transparency in the visible domain of less than 10% in the presence of 1% wt and 3% wt of mica fillers. The presence of micas does not affect the thermal behavior of the nanocomposites, which remains similar to that of the neat epoxy resin. The mechanical characterization of the epoxy resin composites revealed an increased Young's modulus, whereas tensile strength was reduced. A peridynamics-based representative volume element approach has been implemented to estimate the effective Young's modulus of the nanomodified materials. The results obtained through this homogenization procedure have been used as input for the analysis of the nanocomposite fracture toughness, which has been carried out by a classical continuum mechanics-peridynamics coupling approach. Comparison with the experimental data confirms the capability of the peridynamics-based strategies to properly model the effective Young's modulus and fracture toughness of epoxy-resin nanocomposites. Finally, the new mica-based composites exhibit high values of volume resistivity, thus being excellent candidates as insulating materials.

Decreased heme-oxygenase (HO)-1 in the macrophages of non-small cell lung cancer.

Reactive oxygen species (ROS) are important in the initiation and promotion of cells to neoplastic growth. Heme-oxygenase (HO)-1, the inducible form of heme-oxygenase, is a cytoprotective enzyme that plays a central role in the defence against oxidative stress and is implicated in the protection of lung tissue against exogenous oxidant exposure. We investigated whether the expression of HO-1 would be decreased in lung tumour as compared with tumour-free adjacent lung tissues. HO-1 expression was quantified by immunohistochemistry in tumour macrophages, in macrophages of tumour-free lung and in tumour cells of surgical specimens collected from 53 individuals with surgically resectable non-small cell lung cancer (NSCLC). The expression of HO-1 was decreased in tumour as compared with tumour-free lung macrophages. No correlations were observed between the expression of HO-1 and both the clinicopathological characteristics and the overall survival of the examined subjects. In conclusion, our data show that macrophages of non-small cell lung cancer exhibit impaired anti-oxidant defence mechanisms, likely mediated by HO-1. Conversely, HO-1 expression does not seem to be associated with lung tumour progression and prognosis.

Pattern of food intolerance in patients with gastro-esophageal reflux symptoms.

BACKGROUND: Many food items have been involved in gastro-esophageal reflux disease pathogenesis and dietary modification has been proposed as first-line treatment. Test-based exclusion diets have shown to significantly reduce reflux symptoms. We aimed to assess the patterns of food intolerance in a series of patients with typical gastro-esophageal reflux symptoms (GERS). METHODS: We retrospectively evaluated all patients with typical reflux symptoms, attending the Centre Study Association on Food Intolerance and Nutrition of Ferrara from January 2010 to October 2015, who resulted positive to at least one food item at the Leucocytotoxic Test. The presence and severity of typical GERS (heartburn and/or acid regurgitation) were assessed using the Gastro-esophageal Reflux Disease Impact Scale (GIS) questionnaire. Only individuals with a GIS Score of at least 5 points were included. RESULTS: Almost all patients (91.1%) were intolerant to at least 5 food items. The most frequent food intolerance (more than 33% of patients) were found for milk (55.4%), lettuce (46.4%), coffee (43.7%), brewer's yeast (42.9%), pork (42.9%), tuna (37.5%), rice (35.7%), sole (34.8%), asparagus (34.8%) and eggs (33.9%). Nine different clusters of food intolerance were detected. CONCLUSIONS: Patients with typical gastro-esophageal reflux symptoms seem to have intolerance to multiple food items, some of which (lettuce, brewer's yeast, tuna, rice, sole and asparagus) have not yet been associated to gastro-esophageal reflux disease.

[Lung cancer in a female non-smoker with occupational exposure to asbestos: a case report]. / Tumore polmonare in donna non fumatrice con esposizione professionale ad amianto: descrizione di un caso clinico.

BACKGROUND: Until recently, asbestos was widely used in a variety of industrial processes. Workers exposed to asbestos may develop lung and pleural diseases such as asbestosis, lung cancer, benign pleural effusion, pleural plaques and mesothelioma. OBJECTIVE: To describe a clinical case of lung cancer in a female non-smoker with occupational exposure to asbestos. METHODS: The clinical and occupational history was based on the information kindly provided by the Occupational Unit of the National Health Service and on the case history of a hospital admittance in 2001, when the patient underwent surgery for lung cancer. RESULTS: The patient worked for 6 years in an asbestos manufacturing industry where she was exposed to high concentrations of asbestos, and then worked for 14 years in a sugar refinery only during the summer. She had benign pleural effusion, pleural plaques, asbestosis and lung cancer. CONCLUSIONS: We concluded that a six-year exposure to high doses of asbestos may induce lung cancer and asbestosis in a female non-smoker.

Test-based exclusion diets in gastro-esophageal reflux disease patients: a randomized controlled pilot trial.

AIM: To investigate the clinical response of gastro-esophageal reflux disease (GERD) symptoms to exclusion diets based on food intolerance tests. METHODS: A double blind, randomized, controlled pilot trial was performed in 38 GERD patients partially or completely non-responders to proton pump inhibitors (PPI) treatment. Fasting blood samples from each patients were obtained; leukocytotoxic test was performed by incubating the blood with a panel of 60 food items to be tested. The reaction of leukocytes (rounding, vacuolization, lack of movement, flattening, fragmentation or disintegration of cell wall) was then evaluated by optical microscopy and rated as follows: level 0 = negative, level 1 = slightly positive, level 2 = moderately positive, and level 3 = highly positive. A "true" diet excluding food items inducing moderate-severe reactions, and a "control" diet including them was developed for each patient. Then, twenty patients received the "true" diet and 18 the "control" diet; after one month (T1) symptoms severity was scored by the GERD impact scale (GIS). Hence, patients in the "control" group were switched to the "true" diet, and symptom severity was re-assessed after three months (T2). RESULTS: At baseline (T0) the mean GIS global score was 6.68 (range: 5-12) with no difference between "true" and control group (6.6 ± 1.19 vs 6.7 ± 1.7). All patients reacted moderately/severely to at least 1 food (range: 5-19), with a significantly greater number of food substances inducing reaction in controls compared with the "true" diet group (11.6 vs 7.0, P < 0.001). Food items more frequently involved were milk, lettuce, brewer's yeast, pork, coffee, rice, sole asparagus, and tuna, followed by eggs, tomato, grain, shrimps, and chemical yeast. At T1 both groups displayed a reduction of GIS score ("true" group 3.3 ± 1.7, -50%, P = 0.001; control group 4.9 ± 2.8, -26.9%, P = 0.02), although the GIS score was significantly lower in "true" vs "control" group (P = 0.04). At T2, after the diet switch, the "control" group showed a further reduction in GIS score (2.7 ± 1.9, -44.9%, P = 0.01), while the "true" group did not (2.6 ± 1.8, -21.3%, P = 0.19), so that the GIS scores didn't differ between the two groups. CONCLUSION: Our results suggest that food intolerance may play a role in GERD symptoms development, and leucocytotoxic test-based exclusion diets may be a possible therapeutic approach when PPI are not effective or indicated.

Chronic obstructive pulmonary disease (COPD) and occupational exposures.

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality in both industrialized and developing countries. Cigarette smoking is the major risk factor for COPD. However, relevant information from the literature published within the last years, either on general population samples or on workplaces, indicate that about 15% of all cases of COPD is work-related. Specific settings and agents are quoted which have been indicated or confirmed as linked to COPD. Coal miners, hard-rock miners, tunnel workers, concrete-manufacturing workers, nonmining industrial workers have been shown to be at highest risk for developing COPD. Further evidence that occupational agents are capable of inducing COPD comes from experimental studies, particularly in animal models. In conclusion, occupational exposure to dusts, chemicals, gases should be considered an established, or supported by good evidence, risk factor for developing COPD. The implications of this substantial occupational contribution to COPD must be considered in research planning, in public policy decision-making, and in clinical practice.