A commentary on the inhibition of human TPC2 channel by the natural flavonoid naringenin: methods, experiments, and ideas

: Human endo-lysosomes possess a class of proteins called TPC channels on their membrane, which are essential for proper cell functioning. This protein family can be functionally studied by expressing them in plant vacuoles. Inhibition of hTPC activity by naringenin, one of the main flavonoids present in the human diet, has the potential to be beneficial in severe human diseases such as solid tumor development, melanoma, and viral infections. We attempted to identify the molecular basis of the interaction between hTPC2 and naringenin, using ensemble docking on molecular dynamics (MD) trajectories, but the specific binding site remains elusive, posing a challenge that could potentially be addressed in the future by increased computational power in MD and the combined use of microscopy techniques such as cryo-EM

Functional and pharmacological evaluation of novel GLA variants in Fabry disease identifies six (two de novo) causative mutations and two amenable variants to the chaperone DGJ

Abstract Background Allelic heterogeneity is an important feature of the GLA gene for which almost 900 known genetic variants have been discovered so far. Pathogenetic GLA variants cause alpha-galactosidase A (α-Gal A) enzyme deficiency leading to the X-linked lysosomal storage disorder Fabry disease (FD). Benign GLA intronic and exonic variants ( e.g. pseudodeficient p.Asp313Tyr) have also been described. Some GLA missense variants, previously deemed to be pathogenetic ( e.g. p.Glu66Gln and p.Arg118Cys), they have been reclassified as benign after re-evaluation by functional and population studies. Hence, the functional role of novel GLA variants should be investigated to assess their clinical relevance. Results We identified six GLA variants in 4 males and 2 females who exhibited symptoms of FD: c.159C>G p.(Asn53Lys), c.400T>C p.(Tyr134His), c.680G>C (p.Arg227Pro), c.815A>T p.(Asn272Ile), c.907A>T p.(Ile303Phe) and c.1163_1165delTCC (p.Leu388del). We evaluated their impact on the α-Gal A protein by bioinformatic analysis and homology modelling, by analysis of the GLA mRNA, and by site-directed mutagenesis and in vitro expression studies. We also measured their responsiveness to the pharmacological chaperone DGJ. Conclusions The six detected GLA variants cause deficient α-Gal A activity and impairment or loss of the protein wild-type structure. We found p.Asn53Lys and p.Ile303Phe variants to be susceptible to DGJ

Lopinavir/Ritonavir and Darunavir/Cobicistat in Hospitalized COVID-19 Patients: Findings From the Multicenter Italian CORIST Study

Background: Protease inhibitors have been considered as possible therapeutic agents for COVID-19 patients. Objectives: To describe the association between lopinavir/ritonavir (LPV/r) or darunavir/cobicistat (DRV/c) use and in-hospital mortality in COVID-19 patients. Study Design: Multicenter observational study of COVID-19 patients admitted in 33 Italian hospitals. Medications, preexisting conditions, clinical measures, and outcomes were extracted from medical records. Patients were retrospectively divided in three groups, according to use of LPV/r, DRV/c or none of them. Primary outcome in a time-to event analysis was death. We used Cox proportional-hazards models with inverse probability of treatment weighting by multinomial propensity scores. Results: Out of 3,451 patients, 33.3% LPV/r and 13.9% received DRV/c. Patients receiving LPV/r or DRV/c were more likely younger, men, had higher C-reactive protein levels while less likely had hypertension, cardiovascular, pulmonary or kidney disease. After adjustment for propensity scores, LPV/r use was not associated with mortality (HR = 0.94, 95% CI 0.78 to 1.13), whereas treatment with DRV/c was associated with a higher death risk (HR = 1.89, 1.53 to 2.34, E-value = 2.43). This increased risk was more marked in women, in elderly, in patients with higher severity of COVID-19 and in patients receiving other COVID-19 drugs. Conclusions: In a large cohort of Italian patients hospitalized for COVID-19 in a real-life setting, the use of LPV/r treatment did not change death rate, while DRV/c was associated with increased mortality. Within the limits of an observational study, these data do not support the use of LPV/r or DRV/c in COVID-19 patients

Naringenin as a novel inhibitor of Two-Pore Channel 2 controlling the angiogenic process in vitro and in vivo

Two Pore Channels (TPCs) are an emerging family of intracellular channels, expressed on acidic compartments, which mediate calcium signaling evoked by NAADP. In particular, we demonstrated that TPC2 isoform has a main role in angiogenesis (Favia et al. PNAS 2014 Nov 4;111(44):E4706-15). TPC2 inhibition is emerging as a key therapeutic step in a range of important pathological conditions including the progression and metastatic potential of cancer, Parkinson’s disease, and Ebola virus infection. We introduce naringenin, a natural flavonoid, as a novel TPC2 inhibitor as shown by electrophysiological evidence in a heterologous system, i.e. Arabidopsis vacuoles lacking endogenous TPCs. In view of the control exerted by TPC2 on intracellular calcium signaling and angiogenesis, we demonstrate that naringenin dampens intracellular calcium responses of human endothelial cells stimulated with VEGF, histamine or NAADP-AM, but not with ATP or Angiopoietin-1. The ability of naringenin to impair TPC2-dependent biological activities was further explored in an established in vivo model in which VEGF-containing matrigel plugs implanted in mice failed to be vascularized in the presence of naringenin. Our present data suggest that naringenin inhibition of TPC2 activity and the observed inhibition of angiogenic response to VEGF are linked by impaired intracellular calcium signaling. The relationship we describe here between naringenin and TPC2 is therefore likely to have wider implications in systems other than the vascular system, thus representing a novel tool for experimental, and possibly even clinical, research purposes

The Discovery of Naringenin as Endolysosomal Two-Pore Channel Inhibitor and Its Emerging Role in SARS-CoV-2 Infection

: The flavonoid naringenin (Nar), present in citrus fruits and tomatoes, has been identified as a blocker of an emerging class of human intracellular channels, namely the two-pore channel (TPC) family, whose role has been established in several diseases. Indeed, Nar was shown to be effective against neoangiogenesis, a process essential for solid tumor progression, by specifically impairing TPC activity. The goal of the present review is to illustrate the rationale that links TPC channels to the mechanism of coronavirus infection, and how their inhibition by Nar could be an efficient pharmacological strategy to fight the current pandemic plague COVID-19

A commentary on the inhibition of human TPC2 channel by the natural flavonoid naringenin: Methods, experiments, and ideas

Human endo-lysosomes possess a class of proteins called TPC channels on their membrane, which are essential for proper cell functioning. This protein family can be functionally studied by expressing them in plant vacuoles. Inhibition of hTPC activity by naringenin, one of the main flavonoids present in the human diet, has the potential to be beneficial in severe human diseases such as solid tumor development, melanoma, and viral infections. We attempted to identify the molecular basis of the interaction between hTPC2 and naringenin, using ensemble docking on molecular dynamics (MD) trajectories, but the specific binding site remains elusive, posing a challenge that could potentially be addressed in the future by increased computational power in MD and the combined use of microscopy techniques such as cryo-EM

Design, Analysis and Realisation of a Magnetic Gear Prototype with Experimental Validation

Since years ’80s of last century magnetic gears have been considered as possible power transmission systems, in substitution of classical mechanical transmissions. They are able to transmit torque, between two mechanical axes, in a contactless way, through the interaction of two coaxial permanent magnets rotors with a set of ferromagnetic poles. Several advantages can be achieved from the physical isolation between moving parts, as the absence of lubrication, no mechanical fatigue, the reduction of noise, wearing and need of maintenance, as well as the integrated overload protection function. A test bench for experimental analysis of the magneto-mechanical performance and the dynamics of a magnetic gear prototype has been devised, designed and realised. Magnetic gears have been equipped with pick-up coils to measure the magnetic flux waveforms in order to compare them with simulation analyses. Details about the test bench, its drives and controls and experimental results obtained by tests are presented and discussed