Urothelial TRPV1: TRPV1-Reporter Mice, a Way to Clarify the Debate?

A commentary on Trpv1 reporter mice reveal highly restricted brain distribution and functional expression in arteriolar smooth muscle cell

Evaluating the 'return on patient engagement initiatives' in medicines research and development: A literature review

Search strategy and inclusion criteria. We undertook a scoping literature review using a systematic search, including academic and grey literature with a focus on evaluation approaches or outcomes associated with patient engagement. No date limits were applied other than a cut-off of publications after July 2018. Data extraction and synthesis. Data were extracted from 91 publications, coded and thematically analysed. Main results. A total of 18 benefits and 5 costs of patient engagement were identified, mapped with 28 possible indicators for their evaluation. Several quantitative and qualitative methods were found for evaluation of benefits and costs of patient engagement. Discussion and conclusions. Currently available indicators and methods are of some use in measuring impact but are not sufficient to understand the pathway to impact, nor whether interaction between researchers and patients leads to change. We suggest that the impacts of patient engagement can best be determined not by applying single indicators, but a coherent set of measures

Bestrophine-1 (identification moléculaire)

La lésion nerveuse périphérique provoque dans les neurones sensoriels le passage d'un état de transmission à un état de régénération dans l'optique de recouvrer la sensibilité périphérique. Des modifications phénotypiques importantes supportent ce processus. Des études précédentes ont montré que les neurones de ganglions rachidiens dorsaux présentent des modifications importantes de l'homéostasie chlorure. En effet, ils expriment un courant chlorure activé par le calcium (CaCC) et leur concentration intracellulaire en ions chlorures est augmentée. Les travaux effectués au cours de ma thèse de doctorat montrent que le traumatisme périphérique induit la surexpression du gène Best1, dont la protéine Bestrophin-1, sous tend l'expression de CaCC dans les neurones sensoriels, par des méthodes d'enregistrements électrophysiologiques et d'expression génique. De plus, l'étude des mécanismes de régulation de CaCC permettent de mettre en lumière une implication de la matrice extracellulaire dans la sécrétion de la cytokine interleukin-6, qui en retour favorise la surexpression du gène Best1. Les ions chlorures participent également à l'activation de CaCC, sans pour autant que le mécanisme ne soit pour l'heure défini. Dans un troisième temps, l'inhibition par ARN interférence et l'invalidation génétique de la Bestrophin-1 conduit à une diminution de la vitesse de pousse in vitro des neurites ainsi qu'à un ralentissement du recouvrement de la sensibilité périphérique. Cette implication de la Bestrophin-1 dans les mécanismes de régénération peut être due à la sensibilité du canal à un étirement membranaireSensory neurons shift from a transmitting mode to a regenerative state following peripheral nerve injury. This modification is necessary to the peripheral sensitivity recovery. Massive phenotypic changes support this process. Previous study demonstrated that neurons from dorsal root ganglia show important changes in their chloride homeostasis. Indeed, they express calcium-activated chloride currents (CaCC) and they present a two fold increase in their intracellular chloride concentration. We demonstrate that peripheral nerve injury leads to the sur-expression of the Best1 gene, and its protein supports functional expression of CaCC by electrophysiological recordings and quantitative gene expression strategies. Moreover, studying regulation mechanisms highlight the involvement of the extracellular matrix in the secretion of the cytokine interleukin-6, which in turn promotes the expression of Best1. Chloride ions are part of the CaCC regulatory machinery, but the mechanism is still elusive. In the third part, we demonstrate that Bestrophin-1 inhibition by RNA interference and genetic invalidation decreases the neurite outgrowth velocity in vivo and slow down the peripheral sensibility recovery. The Bestrophin-1 involvement in regenerative process might be due to its membrane stretch sensibilityMONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Non-neuronal BDNF, a key player in development of central sensitization and neuropathic pain

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Single-cell electroporation of adult sensory neurons for gene screening with RNA interference mechanism.

International audienceRNA interference appears as a technique of choice to identify gene candidate or to evaluate gene function. To date, a main problem is to achieve high transfection efficiencies on native cells such as adult neurons. In addition, transfection on organ or mass culture does not allow to approach the cellular diversity. Dorsal root ganglia are composed with several cell types to convey somato-sensory sensations. Single-cell electroporation is the most recent method of transfection that allows the introduction into cells, not only dyes or drugs, but also large molecules such plasmid DNA expression constructs. In the present study, the application of the RNA interference technique with the use of single-cell electroporation was evaluated in primary culture of adult sensory neurons. With the use of fluorescent dextran as a co-transfectant, we first determined the non-specific siRNA concentration leading to cell death. Efficacy of siRNA at the non-toxic concentration was demonstrated at the protein level by extinction of GFP fluorescence in actin-GFP neurons and by the inhibition of the intracellular Cl(-) concentration increase following activation of the membrane co-transporter Na(+)-K(+)-2Cl(-) in regenerating axotomized sensory neurons. Altogether, these data show that delivery of siRNAs by single-cell electroporation leads to the induction of functional RNA interference

Crucial Role of TRPC1 and TRPC4 in Cystitis-Induced Neuronal Sprouting and Bladder Overactivity

PURPOSE: During cystitis, increased innervation of the bladder by sensory nerves may contribute to bladder overactivity and pain. The mechanisms whereby cystitis leads to hyperinnervation of the bladder are, however, poorly understood. Since TRP channels have been implicated in the guidance of growth cones and survival of neurons, we investigated their involvement in the increases in bladder innervation and bladder activity in rodent models of cystitis. MATERIALS AND METHODS: To induce bladder hyperactivity, we chronically injected cyclophosphamide in rats and mice. All experiments were performed a week later. We used quantitative transcriptional analysis and immunohistochemistry to determine TRP channel expression on retrolabelled bladder sensory neurons. To assess bladder function and referred hyperalgesia, urodynamic analysis, detrusor strip contractility and Von Frey filament experiments were done in wild type and knock-out mice. RESULTS: Repeated cyclophosphamide injections induce a specific increase in the expression of TRPC1 and TRPC4 in bladder-innervating sensory neurons and the sprouting of sensory fibers in the bladder mucosa. Interestingly, cyclophosphamide-treated Trpc1/c4(-/-) mice no longer exhibited increased bladder innervations, and, concomitantly, the development of bladder overactivity was diminished in these mice. We did not observe a difference neither in bladder contraction features of double knock-out animals nor in cyclophosphamide-induced referred pain behavior. CONCLUSIONS: Collectively, our data suggest that TRPC1 and TRPC4 are involved in the sprouting of sensory neurons following bladder cystitis, which leads to overactive bladder disease.status: publishe

Cav3.2 calcium channels: the key protagonist of the supraspinal effect of paracetamol

International audienceTo exert its analgesic action, paracetamol requires complex metabolism to produce a brain-specific lipoamino acid compound, AM404, which targets central transient receptor potential vanilloid receptors (TRPV1). Lipoamino acids are also known to induce analgesia through T-type calcium-channel inhibition (Cav3.2). In this study we show that the antinociceptive effect of paracetamol in mice is lost when supraspinal Cav3.2 channels are inhibited. Therefore, we hypothesized a relationship between supraspinal Cav3.2 and TRPV1, via AM404, which mediates the analgesic effect of paracetamol. AM404 is able to activate TRPV1 and weakly inhibits Cav3.2. Interestingly, activation of TRPV1 induces a strong inhibition of Cav3.2 current. Supporting this, intracerebroventricular administration of AM404 or capsaicin produces antinociception that is lost in Cav3.2−/− mice. Our study, for the first time, 1) provides a molecular mechanism for the supraspinal antinociceptive effect of paracetamol; 2) identifies the relationship between TRPV1 and the Cav3.2 channel; and 3) suggests supraspinal Cav3.2 inhibition as a potential pharmacological strategy to alleviate pain