N-type Ca2+ Channels Are Present in Secretory Granules and Are Transiently Translocated to the Plasma Membrane during Regulated Exocytosis

Abstract An intracellular pool of N-type voltage-operated calcium channels has recently been described in different neuronal cell lines. We have now further characterized the intracellular pool of N-type calcium channels in both IMR32 human neuroblastoma and PC12 rat pheochromocytoma cells. Intracellular N-type calcium channels were found to be accumulated in subcellular fractions where the chromogranin B-containing secretory granules were also enriched. 125I-ω-Conotoxin GVIA binding assays on fixed and permeabilized cells revealed that intracellular N-type calcium channels translocate to the plasma membrane in cells exposed to secretagogues (KCl, ionomycin, and phorbol esters). The kinetics, Ca2+ and protein kinase C dependence, and brefeldin A insensitivity of N-type calcium channels translocation were similar to the regulated release of chromogranin B, while no correlation was found with the constitutive secretion of a heparan sulfate proteoglycan. A PC12 subclone deficient in the regulated but not in the constitutive pathway of secretion had a small intracellular pool of N-type calcium channels, and no secretagogueinduced translocation occurred in these cells. Calcium channel translocation was accompanied by a stronger response of Fura-2-loaded cells to depolarizing stimuli, suggesting that the newly inserted channels are functional

Early-onset epileptic encephalopathy caused by a reduced sensitivity of Kv7.2 potassium channels to phosphatidylinositol 4,5-bisphosphate

Kv7.2 and Kv7.3 subunits underlie the M-current, a neuronal K(+) current characterized by an absolute functional requirement for phosphatidylinositol 4,5-bisphosphate (PIP(2)). Kv7.2 gene mutations cause early-onset neonatal seizures with heterogeneous clinical outcomes, ranging from self-limiting benign familial neonatal seizures to severe early-onset epileptic encephalopathy (Kv7.2-EE). In this study, the biochemical and functional consequences prompted by a recurrent variant (R325G) found independently in four individuals with severe forms of neonatal-onset EE have been investigated. Upon heterologous expression, homomeric Kv7.2 R325G channels were non-functional, despite biotin-capture in Western blots revealed normal plasma membrane subunit expression. Mutant subunits exerted dominant-negative effects when incorporated into heteromeric channels with Kv7.2 and/or Kv7.3 subunits. Increasing cellular PIP(2) levels by co-expression of type 1γ PI(4)P5-kinase (PIP5K) partially recovered homomeric Kv7.2 R325G channel function. Currents carried by heteromeric channels incorporating Kv7.2 R325G subunits were more readily inhibited than wild-type channels upon activation of a voltage-sensitive phosphatase (VSP), and recovered more slowly upon VSP switch-off. These results reveal for the first time that a mutation-induced decrease in current sensitivity to PIP(2) is the primary molecular defect responsible for Kv7.2-EE in individuals carrying the R325G variant, further expanding the range of pathogenetic mechanisms exploitable for personalized treatment of Kv7.2-related epilepsies

Il turismo sostenibile: una caratterizzazione sulla base di atteggiamenti, valori e tratti di personalità

Questo documento riporta alcuni risultati preliminari di un sondaggio condotto su un campione di convenienza di 323 residenti bilanciati per genere ed età di varie città italiane. Lo studio ha valutato la relazione tra le preferenze degli intervistati per attività e servizi turistici specifici (distinti a seconda del loro maggiore e minore impatto ambientale e sociale) da un lato e un insieme di fattori psico-sociali di natura motivazionale (cioè atteggiamenti, valori, credenze, norme) e disposizionale (cioè il bisogno di chiusura cognitiva). Lo scopo delle analisi presentate qui è stato quello di mostrare come questi fattori possano essere usati per comprendere e meglio spiegare le differenze esistenti tra tipologie di turisti che variano in base alle loro preferenze turistiche. Come previsto, i risultati confermano che i diversi tipi di turisti identificati sulla base delle loro preferenze turistiche, tendono a differire anche in base ai relativi atteggiamenti, credenze, norme e valori ambientali, nonché per la loro affinità con la diversità e il bisogno di chiusura cognitiva. Pertanto, questi fattori dovrebbero essere presi in considerazione da pianificatori e operatori turistici interessati a promuovere forme di turismo più sostenibili

The DNA repair protein ATM as a target in autism spectrum disorder

Impairment of the GABAergic system has been reported in epilepsy, autism, attention deficit hyperactivity disorder, and schizophrenia. We recently demonstrated that ataxia telangiectasia mutated (ATM) directly shapes the development of the GABAergic system. Here, we show for the first time to our knowledge how the abnormal expression of ATM affects the pathological condition of autism. We exploited 2 different animal models of autism, the methyl CpG binding protein 2–null (Mecp2y/–) mouse model of Rett syndrome and mice prenatally exposed to valproic acid, and found increased ATM levels. Accordingly, treatment with the specific ATM kinase inhibitor KU55933 (KU) normalized molecular, functional, and behavioral defects in these mouse models, such as (a) delayed GABAergic development, (b) hippocampal hyperexcitability, (c) low cognitive performances, and (d) social impairments. Mechanistically, we demonstrate that KU administration to WT hippocampal neurons leads to (a) higher early growth response 4 activity on Kcc2b promoter, (b) increased expression of Mecp2, and (c) potentiated GABA transmission. These results provide evidence and molecular substrates for the pharmacological development of ATM inhibition in autism spectrum disorders

Monoclonal Antibodies and Antivirals against SARS-CoV-2 Reduce the Risk of Long COVID: A Retrospective Propensity Score-Matched Case–Control Study

Long COVID is a complex condition affecting quality of life, with limited therapeutic options. We investigated the occurrence of long COVID in subjects receiving early therapy with monoclonal antibodies (mAbs) or antivirals to reduce the risk of COVID-19 progression. In this retrospective study we enrolled 737 adult patients (aged 65.16 ± 13.46; 361F), who experienced COVID-19 between January 2021 and March 2022. Antiviral or mAbs were administered to symptomatic patients who did not require oxygen therapy or hospital admission for SARS-CoV-2 infection, and who were at high risk of progression to severe disease, as identified by age > 65 years or the presence of comorbidities. Long COVID, defined as newly or persistent long-term symptoms 4 weeks after the onset of the acute illness, was reported in 204 cases (28%). Age (OR 1.03; p < 0.001), gender (OR 1.88; p < 0.001) and at least three comorbidities (OR 3.49; p = 0.049) were directly associated with long COVID; conversely, vaccination (OR 0.59; p = 0.005) and mAbs/antivirals (OR 0.44; p = 0.002) were independently associated with a reduced risk of long COVID. At a propensity-score-matched analysis, the mAbs/antivirals group had a significantly lower occurrence of long COVID in comparison with untreated controls (11% vs. 34%; p = 0.001). In conclusion, mAbs and antivirals administered against the progression of COVID-19 were associated with a reduced risk of long COVID