Exploring alternative Zn-binding groups in the design of HDAC inhibitors: squaric acid, N-hydroxyurea, and oxazoline analogues of SAHA

Analogues of suberoylanilide hydroxamic acid (SAHA) were prepared by replacing the Zn-binding group with squaric acid, N-hydroxyurea, and 4-hydroxymethyl oxazoline units, also varying the length of the aliphatic chain. No inhibitory activity on HDAC was observed below 1.0 microM and no cytotoxic activity on different tumor cell lines was seen below 20.0 microM.     

Power dissipation associated with surgical operations' hemodynamics: critical issues and application to the total cavopulmonary connection

The issue of the correct determination of the mechanical power dissipated by the blood flow in the circulatory system is very important. This parameter is particularly critical when the patient's circulation has to overcome structural impairments, such as, e.g., in the case of only one functional ventricle. The surgical palliation of such a condition, which is a relatively common form of congenital heart disease, calls for an optimization of the new connection's hydrodynamics. Starting from the general formulation of the energy dissipation rate in a given control volume, this paper discusses the critical assumptions of the formula usually employed to assess the power dissipation in complex connections, such as the total cavopulmonary connection (TCPC). A new formula is derived, in which the mean elevation of the outlet and inlet sections is shown to be relevant, through the use of the piezometric pressure. Moreover, the flow profile at the boundary of the control volume is also important, since the usual approach implicitly assumes that the flow is perfectly flat: this assumption is doubtful, especially in the venous return (as in the TCPC). In the experimental part of the study, the power dissipation was measured in a physical model of the TCPC, and a large difference was found between the usual method and the proposed one, especially at low regime (85% relative difference, at 1.5 l/min total cardiac output). The proposed approach should be adopted in order to improve the accuracy of the hydrodynamical performance's assessment of surgical connections (e.g., TCPC) or implantable devices (e.g., valved conduit).     

Modulation of Alpha-Synuclein Aggregation by Dopamine Analogs

The action of dopamine on the aggregation of the unstructured alpha-synuclein (α-syn) protein may be linked to the pathogenesis of Parkinson''s disease. Dopamine and its oxidation derivatives may inhibit α-syn aggregation by non-covalent binding. Exploiting this fact, we applied an integrated computational and experimental approach to find alternative ligands that might modulate the fibrillization of α-syn. Ligands structurally and electrostatically similar to dopamine were screened from an established library. Five analogs were selected for in vitro experimentation from the similarity ranked list of analogs. Molecular dynamics simulations showed they were, like dopamine, binding non-covalently to α-syn and, although much weaker than dopamine, they shared some of its binding properties. In vitro fibrillization assays were performed on these five dopamine analogs. Consistent with our predictions, analyses by atomic force and transmission electron microscopy revealed that all of the selected ligands affected the aggregation process, albeit to a varying and lesser extent than dopamine, used as the control ligand. The in silico/in vitro approach presented here emerges as a possible strategy for identifying ligands interfering with such a complex process as the fibrillization of an unstructured protein.     

Somatic point mutations in mtDNA control region are influenced by genetic background and associated with healthy aging: a GEHA study

Tissue specific somatic mutations occurring in the mtDNA control region have been proposed to provide a survival advantage. Data on twins and on relatives of long-lived subjects suggested that the occurrence/accumulation of these mutations may be genetically influenced. To further investigate control region somatic heteroplasmy in the elderly, we analyzed the segment surrounding the nt 150 position (previously reported as specific of Leukocytes) in various types of leukocytes obtained from 195 ultra-nonagenarians sib-pairs of Italian or Finnish origin collected in the frame of the GEHA Project. We found a significant correlation of the mtDNA control region heteroplasmy between sibs, confirming a genetic influence on this phenomenon. Furthermore, many subjects showed heteroplasmy due to mutations different from the C150T transition. In these cases heteroplasmy was correlated within sibpairs in Finnish and northern Italian samples, but not in southern Italians. This suggested that the genetic contribution to control region mutations may be population specific. Finally, we observed a possible correlation between heteroplasmy and Hand Grip strength, one of the best markers of physical performance and of mortality risk in the elderly. Our study provides new evidence on the relevance of mtDNA somatic mutations in aging and longevity and confirms that the occurrence of specific point mutations in the mtDNA control region may represent a strategy for the age-related remodelling of organismal functions.     

Comparison of five commercial anti-SARS-CoV-2 total antibodies and IgG immunoassays after vaccination with BNT162b2 mRNA

BackgroundSince universal vaccinations represents the most effective strategy to mitigate coronavirus disease 2019 (COVID-19), baseline assessment and post-vaccine monitoring of anti-SARS-CoV-2 neutralizing antibodies are essential to vaccination programs. Therefore, this study aimed to compare data of five commercial anti-SARS-CoV2 immunoassays after administration of an mRNA vaccine.MethodsVenous blood was collected from three healthcare workers, receiving a double (30 g) dose of BNT162b2 mRNA Covid-19 vaccine (Comirnaty, Pfizer), on the day of the first vaccine dose and then at fixed intervals for the following 2 months. Anti-SARS-CoV-2 neutralizing antibody response was assayed with Roche Total Ig anti-RBD (receptor binding domain), DiaSorin TrimericS IgG (spike trimer), Beckman Coulter IgG anti-RBD, SNIBE IgG anti-RBD and Technogenetics IgG anti-N/S1.ResultsA total number of 45 samples were drawn at the end of the 2-month study period. The Spearman''s correlations of absolute anti-SARS-CoV-2 antibodies were always excellent (all p<0.001), comprised between 0.967-0.994. Satisfactory results were also observed when absolute antiSARS-CoV-2 antibodies values of the five methods were compared with the mean consensus value, with correlations always higher than 0.979 (all p<0.001). The agreement of anti-SARS-CoV-2 antibodies positivity versus the consensus median positivity ranged between 0.764 and 1.000 (always p<0.001), but become always >0.900 after readjustment of one assay cutoff.ConclusionsAll the immunoassays evaluated in this study appear suitable for monitoring anti-SARS-CoV-2 neutralizing antibodies response in subjects undergoing mRNA COVID-19 vaccination.     

Thromboembolism after COVID-19 vaccine in patients with preexisting thrombocytopenia

While vaccination is the single most effective intervention to drastically reduce severe disease and death following SARS-CoV-2 infection, as shown in UK and Israel, some serious concerns have been raised for an unusual adverse drug reaction (ADR), including vaccine-induced immune thrombotic thrombocytopenia (VITT) with concurrent low platelets as well as capillary leak syndrome. In fact, the overall safety of the vaccine is highlighted by the low frequency of ADR considering that in UK, by the early June, 40 million first doses and 29 million second doses have been injected; nonetheless, 390 thrombotic events, including 71 fatal events have been reported. Interestingly, the cases reported low platelet counts with the presence of anti-platelet factor-4 (PF4) antibodies, indicating an abnormal clotting reaction. Here, out of three referred cases, we report a post-vaccine clinical case of fatal thrombosis with postmortem examination and whole exome sequencing (WES) analysis, whose pathogenesis appeared associated to a preexisting condition of thrombocytopenia due to myelodysplasia.Subject terms: Diseases, Medical research     

Differential analysis of "protein corona" profile adsorbed onto different nonviral gene delivery systems

A shotgun proteomics approach was used to characterize and compare the proteins that lead to the formation of a rich “protein corona” adsorbed onto the surfaces of cationic liposomes (CLs), lipoplexes, and lipid/polycation/DNA (LPD) complexes, when they come into contact with plasma. After separation of the nanoparticle–protein complex from plasma, the protein mixture was digested, and peptides were analyzed by nanoliquid chromatography–Orbitrap LTQ-XL mass spectrometry. The number of proteins bound to lipoplexes was double that of those identified in the corona of CLs (208 vs 105), while 77 proteins were common to both coronas. The number of proteins bound to the surface of the LPD complexes (158, 133 of which are common to lipoplexes) is intermediate between those found in the protein corona of both CLs and lipoplexes. About half of them were found in the protein corona of CLs. By overlapping the three formulations, it can be seen that only 12 proteins are peculiar to LPD complexes. These results may help in designing gene delivery systems capable of binding the minimum possible quantity of proteins that influence transfection negatively, binding selectively proteins capable of helping in steering in vivo the vector toward the target, and obtaining more efficient and effective gene therapy.     

Zebrafish as a tool in Alzheimer's disease research

Alzheimer's disease is the most prevalent form of neurodegenerative disease. Despite many years of intensive research our understanding of the molecular events leading to this pathology is far from complete. No effective treatments have been defined and questions surround the validity and utility of existing animal models. The zebrafish (and, in particular, its embryos) is a malleable and accessible model possessing a vertebrate neural structure and genome. Zebrafish genes orthologous to those mutated in human familial Alzheimer's disease have been defined. Work in zebrafish has permitted discovery of unique characteristics of these genes that would have been difficult to observe with other models. In this brief review we give an overview of Alzheimer's disease and transgenic animal models before examining the current contribution of zebrafish to this research area. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.     

Molecular dynamics study of the conformational stability of esterase 2 from Alicyclobacillus acidocaldarius

Circular dichroism and differential scanning calorimetry measurements showed that esterase 2 from the thermophilic microorganism Alicyclobacillus acidocaldarius, EST2, and its variant in which the first 35 residues have been deleted, EST2-36del, unfold reversibly on increasing temperature, and possess two cooperative and coupled domains [12]. Structural features of the α/β hydrolase fold of EST2, with nine α-helices packed against the central twisted β-sheet, do not allow a straightforward identification of these two cooperative and coupled domains. Molecular dynamics simulations, each one 20 ns long, have been performed at 300, 400 and 500 K, on both proteins in explicit water. Suitable analysis of MD trajectories has allowed a reliable identification of the two cooperative domains (i.e., the less stable one corresponds to external α-helices, whereas the more stable one corresponds to the central twisted β-sheet) and the attribution of the key coupling role to the last and long α-helix of EST2.     

A case of <Emphasis Type="Italic">Candida krusei</Emphasis> peritonitis secondary to duodenal perforation due to <Emphasis Type="Italic">Candida</Emphasis> duodenitis

A case of a 62-year-old man with Candida krusei peritonitis secondary to duodenal perforation due to Candida duodenitis that was successfully treated with a 14-day course of caspofungin is reported. The potential role of Candida infection in the pathogenesis of peptic ulcers and duodenal perforation is considered. If this role is confirmed, antifungal treatment should be included in the therapeutic armamentarium of peptic disease.