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Depolarization drives neuronal plasticity. However, whether depolarization drives sensitization of peripheral nociceptive neurons remains elusive. By high-content screening (HCS) microscopy, we revealed that depolarization of cultured sensory neurons rapidly activates protein kinase A type II (PKA-II) in nociceptors by calcium influx through CaV1.2 channels. This effect was modulated by calpains but insensitive to inhibitors of cAMP formation, including opioids. In turn, PKA-II phosphorylated Ser1928 in the distal C terminus of CaV1.2, thereby increasing channel gating, whereas dephosphorylation of Ser1928 involved the phosphatase calcineurin. Patch-clamp and behavioral experiments confirmed that depolarization leads to calcium- and PKA-dependent sensitization of calcium currents ex vivo and local peripheral hyperalgesia in the skin in vivo. Our data suggest a local activity-driven feed-forward mechanism that selectively translates strong depolarization into further activity and thereby facilitates hypersensitivity of nociceptor terminals by a mechanism inaccessible to opioids.

Author(s): Claudio Graziano [sup.1] , Patrick Despang [sup.2] , Flavia Palombo [sup.3] , Giulia Severi [sup.1] , Annio Posar [sup.4] [sup.5] , Alessandra Cassio [sup.6] , Tommaso Pippucci [sup.1] , [...]

Voltage-gated calcium channel (VGCC) subunits have been genetically associated with autism spectrum disorders (ASD). The properties of the pore-forming VGCC subunit are modulated by auxiliary β-subunits, which exist in four isoforms (CaVβ1-4). Our previous findings suggested that activation of L-type VGCCs is a common feature of CaVβ2 subunit mutations found in ASD patients. In the current study, we functionally characterized a novel CaVβ1b variant (p.R296C) identified in an ASD patient. We used whole-cell and single-channel patch clamp to study the effect of CaVβ1b_R296C on the function of L- and N-type VGCCs. Furthermore, we used co-immunoprecipitation followed by Western blot to evaluate the interaction of the CaVβ1b-subunits with the RGK-protein Gem. Our data obtained at both, whole-cell and single-channel levels, show that compared to a wild-type CaVβ1b, the CaVβ1b_R296C variant inhibits L- and N-type VGCCs. Interaction with and modulation by the RGK-protein Gem seems to be intact. Our findings indicate functional effects of the CaVβ1b_R296C variant differing from that attributed to CaVβ2 variants found in ASD patients. Further studies have to detail the effects on different VGCC subtypes and on VGCC expression. [ABSTRACT FROM AUTHOR]

Voltage-gated calcium-channels (VGCCs) are heteromers consisting of several subunits. Mutations in the genes coding for VGCC subunits have been reported to be associated with autism spectrum disorder (ASD). In a previous study, we identified electrophysiologically relevant missense mutations of Ca V β 2 subunits of VGCCs. From this, we derived the hypothesis that several Ca V β 2 -mutations associated with ASD show common features sensitizing LTCCs and/or enhancing currents. Using a Ca V β 2d backbone, we performed extensive whole-cell and single-channel patch-clamp analyses of Ba2+ currents carried by Ca v 1.2 pore subunits co-transfected with the previously described Ca V β 2 mutations (G167S, S197F) as well as a recently identified point mutation (V2D). Furthermore, the interaction of the mutated Ca V β 2d subunits with the RGK protein Gem was analyzed by co-immunoprecipitation assays and electrophysiological studies. Patch-clamp analyses revealed that all mutations increase Ba2+ currents, e.g. by decreasing inactivation or increasing fraction of active sweeps. All Ca V β 2 mutations interact with Gem, but differ in the extent and characteristics of modulation by this RGK protein (e.g. decrease of fraction of active sweeps: Ca V β 2d_G167S > Ca V β 2d_V2D > Ca V β 2d_S197F). In conclusion, patch-clamp recordings of ASD-associated Ca V β 2d mutations revealed differential modulation of Ba2+ currents carried by Ca V 1.2 suggesting kind of an "electrophysiological fingerprint" each. The increase in current finally observed with all Ca V β 2d mutations analyzed might contribute to the complex pathophysiology of ASD and by this indicate a possible underlying molecular mechanism. • Ca v β subunits modulate voltage-gated Ca2+ channels (VGCC) and were linked to diseases like autism spectrum disorder (ASD) • three different ASD-associated Ca v β 2 mutations (p.V2D, p.G167S, p.S197F) lead to increased Ba2+ currents carried by L-type VGCCs • these Ca v β 2 mutations interact with the RGK-protein Gem although the modulation pattern depends on the particular mutation • each Ca v β 2 mutation investigated appears to display a kind of "electrophysiological fingerprint" • Ca v β 2 mutations may contribute to the complex pathophysiology of ASD by causing an imbalance of Ca2+-signaling [ABSTRACT FROM AUTHOR]

Background: Cardiovascular disease is still the major cause of death worldwide. Beside the elevated blood pressure, a major modifiable risk factor is the elevated low-density lipoprotein (LDL) cholesterol. Although both risk factors are well manageable, therapeutic control remains poor with low adherence to medication being a major cause of insufficient treatment success. One solution to overcome this issue is the polypill concept, i.e. a combination of different drugs in one tablet. This not only increases adherence but also significantly improves patients' prognosis by reducing cardiovascular events., Objective: This review focuses on current evidence published in randomized control trials in primary and secondary prevention. A major focus is on the recently published SECURE trial dealing with the polypill in secondary prevention., Current Data: Most trials dealing with the polypill concept focus on the control of risk factors such as blood pressure and LDL cholesterol while lacking a prognostic benefit in the form of a reduction in cardiovascular events. Recent trials such as the HOPE‑3, PolyIran and TIPS‑3 trials have shown a prognostic improvement for the polypill in primary prevention. In secondary prevention there has been a lack of prognostic benefit for the polypill to date. The recently published SECURE trial closed this gap by showing a significant reduction in major adverse cardiovascular events in post-infarct patients and also showing a reduction in cardiovascular death by 33%., Conclusion: The concept of the polypill has evolved from a comfort method for patients aimed at facilitating adherence to an innovative therapeutic concept with a proven prognostic advantage compared to current treatment practice by reducing cardiovascular events and mortality. Therefore, it is time to implement the concept of the polypill in primary and secondary prevention to improve patients' prognosis and reduce the burden of cardiovascular disease worldwide., (© 2023. The Author(s).)