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The cardiovascular system provides blood supply throughout the body and as such is perpetually applying mechanical forces to cells and tissues. Thus, this system is primed with mechanosensory structures that respond and adapt to changes in mechanical stimuli. Since their discovery in 2010, PIEZO ion channels have dominated the field of mechanobiology. These have been proposed as the long-sought-after mechanosensitive excitatory channels involved in touch and proprioception in mammals. However, more and more pieces of evidence point to the importance of PIEZO channels in cardiovascular activities and disease development. PIEZO channel-related cardiac functions include transducing hemodynamic forces in endothelial and vascular cells, red blood cell homeostasis, platelet aggregation, and arterial blood pressure regulation, among others. PIEZO channels contribute to pathological conditions including cardiac hypertrophy and pulmonary hypertension and congenital syndromes such as generalized lymphatic dysplasia and xerocytosis. In this review, we highlight recent advances in understanding the role of PIEZO channels in cardiovascular functions and diseases. Achievements in this quickly expanding field should open a new road for efficient control of PIEZO-related diseases in cardiovascular functions.
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Anemia Hemolítica Congénita , Hipertensión Pulmonar , Animales , Femenino , Humanos , Presión Sanguínea , Biofisica , Hidropesía Fetal , MamíferosRESUMEN
The enteric nervous system (ENS) is a complex network of diverse molecularly defined classes of neurons embedded in the gastrointestinal wall and responsible for controlling the major functions of the gut. As in the central nervous system, the vast array of ENS neurons is interconnected by chemical synapses. Despite several studies reporting the expression of ionotropic glutamate receptors in the ENS, their roles in the gut remain elusive. Here, by using an array of immunohistochemistry, molecular profiling and functional assays, we uncover a new role for d-serine (d-Ser) and non-conventional GluN1-GluN3 N-methyl d-aspartate receptors (NMDARs) in regulating ENS functions. We demonstrate that d-Ser is produced by serine racemase (SR) expressed in enteric neurons. By using both in situ patch clamp recording and calcium imaging, we show that d-Ser alone acts as an excitatory neurotransmitter in the ENS independently of the conventional GluN1-GluN2 NMDARs. Instead, d-Ser directly gates the non-conventional GluN1-GluN3 NMDARs in enteric neurons from both mouse and guinea-pig. Pharmacological inhibition or potentiation of GluN1-GluN3 NMDARs had opposite effects on mouse colonic motor activities, while genetically driven loss of SR impairs gut transit and fluid content of pellet output. Our results demonstrate the existence of native GluN1-GluN3 NMDARs in enteric neurons and open new perspectives on the exploration of excitatory d-Ser receptors in gut function and diseases.
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Many ion channels have been described as mechanosensitive according to various criteria. Most broadly defined, an ion channel is called mechanosensitive if its activity is controlled by application of a physical force. The last decade has witnessed a revolution in mechanosensory physiology at the molecular, cellular, and system levels, both in health and in diseases. Since the discovery of the PIEZO proteins as prototypical mechanosensitive channel, many proteins have been proposed to transduce mechanosensory information in mammals. However, few of these newly identified candidates have all the attributes of bona fide, pore-forming mechanosensitive ion channels. In this perspective, we will cover and discuss new data that have advanced our understanding of mechanosensation at the molecular level.
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Canales Iónicos , Mecanotransducción Celular , Animales , Canales Iónicos/metabolismo , Mamíferos/metabolismo , Mecanotransducción Celular/fisiologíaRESUMEN
A variety of mechanosensory neurons are involved in touch, proprioception, and pain. Many molecular components of the mechanotransduction machinery subserving these sensory modalities remain to be discovered. Here, we combine recordings of mechanosensitive (MS) currents in mechanosensory neurons with single-cell RNA sequencing. Transcriptional profiles are mapped onto previously identified sensory neuron types to identify cell-type correlates between datasets. Correlation of current signatures with single-cell transcriptomes provides a one-to-one correspondence between mechanoelectric properties and transcriptomically defined neuronal populations. Moreover, a gene-expression differential comparison provides a set of candidate genes for mechanotransduction complexes. Piezo2 is expectedly found to be enriched in rapidly adapting MS current-expressing neurons, whereas Tmem120a and Tmem150c, thought to mediate slow-type MS currents, are uniformly expressed in all mechanosensory neuron subtypes. Further knockdown experiments disqualify them as mediating MS currents in sensory neurons. This dataset constitutes an open resource to explore further the cell-type-specific determinants of mechanosensory properties.
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Ganglios Espinales/metabolismo , Perfilación de la Expresión Génica , Mecanotransducción Celular/genética , Neuronas/metabolismo , Transcriptoma , Animales , Ganglios Espinales/citología , Regulación de la Expresión Génica , Células HEK293 , Humanos , Canales Iónicos/genética , Canales Iónicos/metabolismo , Masculino , Potenciales de la Membrana , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Células 3T3 NIH , Técnicas de Placa-Clamp , RNA-Seq , Análisis de la Célula IndividualRESUMEN
Mepyramine, a first-generation antihistamine targeting the histamine H(1) receptor, was extensively prescribed to patients suffering from allergic reactions and urticaria. Serious adverse effects, especially in case of overdose, were frequently reported, including drowsiness, impaired thinking, convulsion, and coma. Many of these side effects were associated with the blockade of histaminergic or cholinergic receptors. Here we show that mepyramine directly inhibits a variety of voltage-gated sodium channels, including the Tetrodotoxin-sensitive isoforms and the main isoforms (Nav1.7, Nav1.8, and Nav1.9) of nociceptors. Estimated IC50 were within the range of drug concentrations detected in poisoned patients. Mepyramine inhibited sodium channels through fast- or slow-inactivated state preference depending on the isoform. Moreover, mepyramine inhibited the firing responses of C- and Aß-type nerve fibers in ex vivo skin-nerve preparations. Locally applied mepyramine had analgesic effects on the scorpion toxin-induced excruciating pain and produced pain relief in acute, inflammatory, and chronic pain models. Collectively, these data provide evidence that mepyramine has the potential to be developed as a topical analgesic agent.
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Artritis Experimental/complicaciones , Ganglios Espinales/efectos de los fármacos , Canal de Sodio Activado por Voltaje NAV1.8/fisiología , Nociceptores/efectos de los fármacos , Dolor/tratamiento farmacológico , Pirilamina/farmacología , Bloqueadores de los Canales de Sodio/farmacología , Potenciales de Acción , Animales , Ganglios Espinales/metabolismo , Ganglios Espinales/patología , Antagonistas de los Receptores Histamínicos H1/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Canal de Sodio Activado por Voltaje NAV1.8/química , Nociceptores/metabolismo , Nociceptores/patología , Dolor/etiología , Dolor/metabolismo , Dolor/patologíaRESUMEN
Cholangiocytes actively contribute to the final composition of secreted bile. These cells are exposed to abnormal mechanical stimuli during obstructive cholestasis, which has a deep impact on their function. However, the effects of mechanical insults on cholangiocyte function are not understood. Combining gene silencing and pharmacological assays with live calcium imaging, we probed molecular candidates essential for coupling mechanical force to ATP secretion in mouse cholangiocytes. We show that Piezo1 and Pannexin1 are necessary for eliciting the downstream effects of mechanical stress. By mediating a rise in intracellular Ca2+, Piezo1 acts as a mechanosensor responsible for translating cell swelling into activation of Panx1, which triggers ATP release and subsequent signal amplification through P2X4R. Co-immunoprecipitation and pull-down assays indicated physical interaction between Piezo1 and Panx1, which leads to stable plasma membrane complexes. Piezo1-Panx1-P2X4R ATP release pathway could be reconstituted in HEK Piezo1 KO cells. Thus, our data suggest that Piezo1 and Panx1 can form a functional signaling complex that controls force-induced ATP secretion in cholangiocytes. These findings may foster the development of novel therapeutic strategies for biliary diseases.
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Adenosina Trifosfato , Conexinas , Células Epiteliales , Canales Iónicos , Proteínas del Tejido Nervioso , Animales , Calcio/metabolismo , Membrana Celular/metabolismo , Conexinas/genética , Células Epiteliales/metabolismo , Canales Iónicos/genética , Canales Iónicos/metabolismo , Ratones , Proteínas del Tejido Nervioso/genética , Transducción de SeñalRESUMEN
BACKGROUND AND PURPOSE: Protoxin II (ProTx II) is a high affinity gating modifier that is thought to selectively block the Nav 1.7 voltage-dependent Na+ channel, a major therapeutic target for the control of pain. We aimed at producing ProTx II analogues entitled with novel functionalities for cell distribution studies and biochemical characterization of its Nav channel targets. EXPERIMENTAL APPROACH: We took advantage of the high affinity properties of the peptide, combined to its slow off rate, to design a number of new tagged analogues useful for imaging and biochemistry purposes. We used high-throughput automated patch-clamp to identify the analogues best matching the native properties of ProTx II and validated them on various Nav -expressing cells in pull-down and cell distribution studies. KEY RESULTS: Two of the produced ProTx II analogues, Biot-ProTx II and ATTO488-ProTx II, best emulate the pharmacological properties of unlabelled ProTx II, whereas other analogues remain high affinity blockers of Nav 1.7. The biotinylated version of ProTx II efficiently works for the pull-down of several Nav isoforms tested in a concentration-dependent manner, whereas the fluorescent ATTO488-ProTx II specifically labels the Nav 1.7 channel over other Nav isoforms tested in various experimental conditions. CONCLUSIONS AND IMPLICATIONS: The properties of these ProTx II analogues as tools for Nav channel purification and cell distribution studies pave the way for a better understanding of ProTx II channel receptors in pain and their pathophysiological implications in sensory neuronal processing. The new fluorescent ProTx II should also be useful in the design of new drug screening strategies.
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Venenos de Araña , Humanos , Canal de Sodio Activado por Voltaje NAV1.7 , Dolor , PéptidosRESUMEN
Oral amitriptyline hydrochloride (amitriptyline) is ineffective against some forms of chronic pain and is often associated with dose-limiting adverse events. We evaluated the potential effectiveness of high-dose topical amitriptyline in a preliminary case series of chemotherapy-induced peripheral neuropathy patients and investigated whether local or systemic adverse events associated with the use of amitriptyline were present in these patients. We also investigated the mechanism of action of topically administered amitriptyline in mice. Our case series suggested that topical 10% amitriptyline treatment was associated with pain relief in chemotherapy-induced peripheral neuropathy patients, without the side effects associated with systemic absorption. Topical amitriptyline significantly increased mechanical withdrawal thresholds when applied to the hind paw of mice, and inhibited the firing responses of C-, Aß- and Aδ-type peripheral nerve fibers in ex vivo skin-saphenous nerve preparations. Whole-cell patch-clamp recordings on cultured sensory neurons revealed that amitriptyline was a potent inhibitor of the main voltage-gated sodium channels (Nav1.7, Nav1.8, and Nav1.9) found in nociceptors. Calcium imaging showed that amitriptyline activated the transient receptor potential cation channel, TRPA1. Our case series indicated that high-dose 10% topical amitriptyline could alleviate neuropathic pain without adverse local or systemic effects. This analgesic action appeared to be mediated through local inhibition of voltage-gated sodium channels. PERSPECTIVE: Our preliminary case series suggested that topical amitriptyline could provide effective pain relief for chemotherapy-induced peripheral neuropathy patients without any systemic or local adverse events. Investigation of the mechanism of this analgesic action in mice revealed that this activity was mediated through local inhibition of nociceptor Nav channels.
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Amitriptilina/farmacología , Analgésicos no Narcóticos/farmacología , Antineoplásicos/efectos adversos , Dolor Nociceptivo/tratamiento farmacológico , Nociceptores/efectos de los fármacos , Enfermedades del Sistema Nervioso Periférico/inducido químicamente , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológico , Canal Catiónico TRPA1/efectos de los fármacos , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Canales de Sodio Activados por Voltaje/efectos de los fármacos , Administración Tópica , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Amitriptilina/administración & dosificación , Amitriptilina/efectos adversos , Analgésicos no Narcóticos/administración & dosificación , Analgésicos no Narcóticos/efectos adversos , Animales , Conducta Animal/efectos de los fármacos , Niño , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Canal de Sodio Activado por Voltaje NAV1.7 , Canal de Sodio Activado por Voltaje NAV1.8 , Canal de Sodio Activado por Voltaje NAV1.9 , Bloqueadores del Canal de Sodio Activado por Voltaje/administración & dosificación , Bloqueadores del Canal de Sodio Activado por Voltaje/efectos adversos , Adulto JovenRESUMEN
Ophthalmic, maxillary, and mandibular branches of the trigeminal nerve provide sensory innervation to orofacial tissues. Trigeminal sensory neurons respond to a diverse array of sensory stimuli to generate distinct sensations, including thermosensation, mechanosensation, itching, and pain. These sensory neurons also detect the distinct sharpness or pungency of many foods and beverages. This SnapShot highlights the transduction ion channels critical to orofacial sensation.
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Sensación/fisiología , Nervio Trigémino/anatomía & histología , Nervio Trigémino/fisiología , Nervios Craneales/anatomía & histología , Nervios Craneales/fisiología , Humanos , Neuronas Aferentes/fisiología , Dolor/fisiopatologíaAsunto(s)
Cefaleas Secundarias/etiología , Óxido Nítrico/toxicidad , Trastornos Relacionados con Sustancias/complicaciones , Cefalea/inducido químicamente , Cefalea/metabolismo , Cefaleas Secundarias/inducido químicamente , Cefaleas Secundarias/metabolismo , Humanos , Canal de Sodio Activado por Voltaje NAV1.9/efectos de los fármacos , Canal de Sodio Activado por Voltaje NAV1.9/metabolismo , Óxido Nítrico/farmacología , Medicamentos bajo Prescripción/efectos adversos , Transducción de Señal/efectos de los fármacos , Trastornos Relacionados con Sustancias/metabolismoRESUMEN
Medication-overuse headaches (MOH) occur with both over-the-counter and pain-relief medicines, including paracetamol, opioids and combination analgesics. The mechanisms that lead to MOH are still uncertain. Here, we show that abnormal activation of Nav1.9 channels by Nitric Oxide (NO) is responsible for MOH induced by triptan migraine medicine. Deletion of the Scn11a gene in MOH mice abrogates NO-mediated symptoms, including cephalic and extracephalic allodynia, photophobia and phonophobia. NO strongly activates Nav1.9 in dural afferent neurons from MOH but not normal mice. Abnormal activation of Nav1.9 triggers CGRP secretion, causing artery dilatation and degranulation of mast cells. In turn, released mast cell mediators potentiates Nav1.9 in meningeal nociceptors, exacerbating inflammation and pain signal. Analysis of signaling networks indicates that PKA is downregulated in trigeminal neurons from MOH mice, relieving its inhibitory action on NO-Nav1.9 coupling. Thus, anomalous activation of Nav1.9 channels by NO, as a result of chronic medication, promotes MOH.
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Cefaleas Secundarias/patología , Trastornos Migrañosos/patología , Canal de Sodio Activado por Voltaje NAV1.9/metabolismo , Neuronas Aferentes/metabolismo , Óxido Nítrico/metabolismo , Triptaminas/efectos adversos , Animales , Péptido Relacionado con Gen de Calcitonina/metabolismo , Degranulación de la Célula/fisiología , Células Cultivadas , Femenino , Cefaleas Secundarias/inducido químicamente , Hiperalgesia/fisiopatología , Masculino , Mastocitos/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Canal de Sodio Activado por Voltaje NAV1.9/genética , Neuronas Aferentes/efectos de los fármacos , Nociceptores/fisiología , Dolor/fisiopatología , Uso Excesivo de Medicamentos Recetados/efectos adversosAsunto(s)
Colesterol/fisiología , Inflamación/complicaciones , Dolor/etiología , Animales , Colesterol/deficiencia , Colesterol/farmacología , Humanos , Inflamación/metabolismo , Canal de Sodio Activado por Voltaje NAV1.9/metabolismo , Canal de Sodio Activado por Voltaje NAV1.9/fisiología , Nociceptores/efectos de los fármacos , Nociceptores/metabolismo , Dolor/metabolismo , Percepción del Dolor/efectos de los fármacosRESUMEN
In the HTML version of this article published online, the abstract contains a typo in the first sentence: "key to understanding intestinal motility anGutn of therapeutic strategies" should read "key to understanding intestinal motility and crucial to the design of theraputic strategies." The PDF version of the article is correct.
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Defects in cerebrospinal fluid (CSF) flow may contribute to idiopathic scoliosis. However, the mechanisms underlying detection of CSF flow in the central canal of the spinal cord are unknown. Here we demonstrate that CSF flows bidirectionally along the antero-posterior axis in the central canal of zebrafish embryos. In the cfap298tm304 mutant, reduction of cilia motility slows transport posteriorly down the central canal and abolishes spontaneous activity of CSF-contacting neurons (CSF-cNs). Loss of the sensory Pkd2l1 channel nearly abolishes CSF-cN calcium activity and single channel opening. Recording from isolated CSF-cNs in vitro, we show that CSF-cNs are mechanosensory and require Pkd2l1 to respond to pressure. Additionally, adult pkd2l1 mutant zebrafish develop an exaggerated spine curvature, reminiscent of kyphosis in humans. These results indicate that CSF-cNs are mechanosensory cells whose Pkd2l1-driven spontaneous activity reflects CSF flow in vivo. Furthermore, Pkd2l1 in CSF-cNs contributes to maintenance of natural curvature of the spine.
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Líquido Cefalorraquídeo/metabolismo , Mecanotransducción Celular , Neuronas/metabolismo , Médula Espinal/metabolismo , Proteínas de Pez Cebra/metabolismo , Pez Cebra/metabolismo , Animales , Cilios/metabolismoRESUMEN
Cholesterol is a major lipid component of the mammalian plasma membrane. While much is known about its metabolism, its transport, and its role in atherosclerotic vascular disease, less is known about its role in neuronal pathophysiology. This study reveals an unexpected function of cholesterol in controlling pain transmission. We show that inflammation lowers cholesterol content in skin tissue and sensory DRG culture. Pharmacological depletion of cellular cholesterol entails sensitization of nociceptive neurons and promotes mechanical and thermal hyperalgesia through the activation of voltage-gated Nav1.9 channels. Inflammatory mediators enhance the production of reactive oxygen species and induce partitioning of Nav1.9 channels from cholesterol-rich lipid rafts to cholesterol-poor non-raft regions of the membrane. Low-cholesterol environment enhances voltage-dependent activation of Nav1.9 channels leading to enhanced neuronal excitability, whereas cholesterol replenishment reversed these effects. Consistently, we show that transcutaneous delivery of cholesterol alleviates hypersensitivity in animal models of acute and chronic inflammatory pain. In conclusion, our data establish that membrane cholesterol is a modulator of pain transmission and shed a new light on the relationship between cholesterol homeostasis, inflammation, and pain.
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Membrana Celular/fisiología , Colesterol/fisiología , Inflamación/fisiopatología , Canal de Sodio Activado por Voltaje NAV1.9/fisiología , Dolor/fisiopatología , Animales , Ganglios Espinales/fisiología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Nociceptores/fisiologíaRESUMEN
In the skin, Merkel cells connect with keratinocytes and Aß nerve fibers to form a touch receptor that functions as a slow adapting mechanoreceptor (slow adapting type 1). In human and mouse Merkel cells, we observed an increased concentration of intracellular Ca2+ ions in response to cold temperature and transient receptor potential melastatine 8 (TRPM8) ion channel agonists. A reduction in the response to cooling and TRPM8 agonists occurred after the addition of TRPM8 antagonists, as well as in TRPM8 knockout mice. Cold temperature and TRPM8 agonists also induced a current that was inhibited by a TRPM8 antagonist. Our results indicate that Merkel cells sense cooling through TRPM8 channels. We hypothesized that cooling modulates the slow adapting type 1 receptor response. Cooling mouse skin to 22°C reduced the slow adapting type 1 receptor discharge frequency. Interestingly, we observed no such reduction in TRPM8 knockout mice. Similarly, in human skin, a temperature of 22°C applied to the slow adapting type 1 receptive field reduced the spiking discharge. Altogether, our results indicate that Merkel cells are polymodal sensory cells that respond to mild cold stimuli through the activation of TRPM8 channels. Thermal activation of Merkel cells, and possibly other TRPM8-expressing non-neuronal cells, such as keratinocytes, potentially adapts the discharge of slow adapting type 1 receptors during cooling.
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Regulación de la Expresión Génica , Células de Merkel/metabolismo , ARN Mensajero/genética , Canales Catiónicos TRPM/genética , Animales , Células Cultivadas , Frío , Humanos , Queratinocitos/citología , Queratinocitos/metabolismo , Mecanorreceptores/metabolismo , Células de Merkel/citología , Ratones , Ratones Noqueados , Modelos Animales , Canales Catiónicos TRPM/biosíntesisRESUMEN
Cold-triggered pain is essential to avoid prolonged exposure to harmfully low temperatures. However, the molecular basis of noxious cold sensing in mammals is still not completely understood. Here, we show that the voltage-gated Nav1.9 sodium channel is important for the perception of pain in response to noxious cold. Nav1.9 activity is upregulated in a subpopulation of damage-sensing sensory neurons responding to cooling, which allows the channel to amplify subthreshold depolarizations generated by the activation of cold transducers. Consequently, cold-triggered firing is impaired in Nav1.9(-/-) neurons, and Nav1.9 null mice and knockdown rats show increased cold pain thresholds. Disrupting Nav1.9 expression in rodents also alleviates cold pain hypersensitivity induced by the antineoplastic agent oxaliplatin. We conclude that Nav1.9 acts as a subthreshold amplifier in cold-sensitive nociceptive neurons and is required for the perception of cold pain under normal and pathological conditions.