Transient Receptor Potential Vanilloid Type Research Articles

Increased TRPV1 Channels and FosB Protein Expression Are Associated with Chronic Epileptic Seizures and Anxiogenic-like Behaviors in a Preclinical Model of Temporal Lobe Epilepsy.

Epilepsies are neurological disorders characterized by chronic seizures and their related neuropsychiatric comorbidities, such as anxiety. The Transient Receptor Potential Vanilloid type-1 (TRPV1) channel has been implicated in the modulation of seizures and anxiety-like behaviors in preclinical models. Here, we investigated the impact of chronic epileptic seizures in anxiety-like behavior and TRPV1 channels expression in a genetic model of epilepsy, the Wistar Audiogenic Rat (WAR) strain. WARs were submitted to audiogenic kindling (AK), a preclinical model of temporal lobe epilepsy (TLE) and behavioral tests were performed in the open-field (OF), and light-dark box (LDB) tests 24 h after AK. WARs displayed increased anxiety-like behavior and TRPV1R expression in the hippocampal CA1 area and basolateral amygdala nucleus (BLA) when compared to control Wistar rats. Chronic seizures increased anxiety-like behaviors and TRPV1 and FosB expression in limbic and brainstem structures involved with epilepsy and anxiety comorbidity, such as the hippocampus, superior colliculus, and periaqueductal gray matter. Therefore, these results highlight previously unrecognized alterations in TRPV1 expression in brain structures involved with TLE and anxiogenic-like behaviors in a genetic model of epilepsy, the WAR strain, supporting an important role of TRPV1 in the modulation of neurological disorders and associated neuropsychiatric comorbidities.

Baicalin treats cerebral ischemia reperfusion-induced brain edema in rats by inhibiting TRPV4 and AQP4 of astrocytes

This study aims to explore the pharmacodynamic effect of baicalin on rat brain edema induced by cerebral ischemia reperfusion injury and discuss the mechanism from the perspective of inhibiting astrocyte swelling, which is expected to serve as a refe-rence for the treatment of cerebral ischemia with Chinese medicine. To be specific, middle cerebral artery occlusion(suture method) was used to induce cerebral ischemia in rats. Rats were randomized into normal group, model group, high-dose baicalin(20 mg·kg~(-1)) group, and low-dose baicalin(10 mg·kg~(-1)) group. The neurobehavior, brain index, brain water content, and cerebral infarction area of rats were measured 6 h and 24 h after cerebral ischemia. Brain slices were stained with hematoxylin and eosin(HE) for the observation of pathological morphology of cerebral cortex after baicalin treatment. Enzyme-linked immunosorbent assay(ELISA) was employed to determine the content of total L-glutathione(GSH) and glutamic acid(Glu) in brain tissue, Western blot to measure the content of glial fibrillary acidic protein(GFAP), aquaporin-4(AQP4), and transient receptor potential vanilloid type 4(TRPV4), and immunohistochemical staining to observe the expression of GFAP. The low-dose baicalin was used for exploring the mechanism. The experimental results showed that the neurobehavioral scores(6 h and 24 h of cerebral ischemia), brain water content, and cerebral infarction area of the model group were increased, and both high-dose and low-dose baicalin can lower the above three indexes. The content of GSH dropped but the content of Glu raised in brain tissue of rats in the model group. Low-dose baicalin can elevate the content of GSH and lower the content of Glu. According to the immunohistochemical staining result, the model group demonstrated the increase in GFAP expression, and swelling and proliferation of astrocytes, and the low-dose baicalin can significantly improve this situation. The results of Western blot showed that the expression of GFAP, TRPV4, and AQP4 in the cerebral cortex of the model group increased, and the low-dose baicalin reduce their expression. The cerebral cortex of rats in the model group was severely damaged, and the low-dose baicalin can significantly alleviate the damage. The above results indicate that baicalin can effectively relieve the brain edema caused by cerebral ischemia reperfusion injury in rats, possibly by suppressing astrocyte swelling and TRPV4 and AQP4.

P046 Effects of CB2 and TRPV1 stimulation on osteoclast overactivity induced by iron in pediatric inflammatory bowel disease

Abstract Background The reduction of bone mineral density and osteoporosis (OP) has an high impact on inflammatory bowel disease (IBD) patients’ health. We have previously shown that a dysregulated iron metabolism occurs in IBD and leads to a decrease in circulating iron concentration and an excessive intracellular sequestration of iron. Studies suggest that iron overload affects the bone, accelerating osteoclasts (OCs) differentiation and activation with consequent bone resorption. The aim of this study was to evaluate the role of Cannabinoid Receptor type 2 (CB2) and transient receptor potential vanilloid type-1 (TRPV1) and of the iron in the development of osteoporosis in pediatric IBD. Methods We enrolled 21 young subjects aged less than 18 years stratified into 3 groups on the basis of the clinical diagnosis: 7 with Ulcerative Colitis (UC) 7 with Crohn’s disease (CD) and 7 were non-IBD controls (CTR). We evaluated the role of CB2 and TRPV1 receptors and of iron in the development of OP in pediatric IBD at diagnosis and analyzed the effects of the pharmacological modulation of CB2 and TRPV1 receptors on osteoclast activity and on iron metabolism by Western Blotting, Tartrate-resistant acid phosphatase assay (TRAP assay) and Iron Assay Kit. We evaluated bone resorption through a commercially available kit visualizing and counting the resorption pits with the optical microscope. Results We observed higher levels of TRPV1 and lower levels of CB2 in the OCs from UC and CD patients compared to CTR. In IBD patients we found a significant up-regulation of osteoclast markers TRAP and Cathepsin K and a consequent osteoclast hyper-activation. The treatments of OCs from IBD patients with the CB2 agonist JWH-133 and the TRPV1 agonist Resinferatoxin, RTX, led to a significant reduction of osteoclastic hyper-activation affecting bone markers expression, number and size of active OCs, and bone resorption area. We also analyzed the [Fe3+] concentration and the expression of iron metabolism modulators, ferroportin1(FPN-1) and divalent metal transporter1(DMT1), in OCs derived from IBD patients. We demonstrated an increase of [Fe3+] and accordingly a decrease of FPN-1 in both groups of patients and an increase of DMT1 levels. After 48h of exposure to JWH-133 and RTX we observed a significant reduction of DMT1 expression in OCs from IBD patients together with a strong increase of FPN-1. Conclusion Our data confirm the well-known role of CB2 and TRPV1 receptors in bone metabolism and suggest that their stimulation can reduce the osteoclast overactivity induced by iron, thus providing new insights into the pathogenesis and in the treatment of pediatric IBD-related bone resorption.

Transient receptor potential vanilloid type 4 (TRPV4) in urinary bladder structure and function.

Bladder pain syndrome (BPS)/interstitial cystitis (IC) is a urologic, chronic pelvic pain syndrome characterized by pelvic pain, pressure, or discomfort with urinary symptoms. Symptom exacerbation (flare) is common with multiple, perceived triggers including stress. Multiple transient receptor potential (TRP) channels (TRPA1, TRPV1, TRPV4) expressed in the bladder have specific tissue distributions in the lower urinary tract (LUT) and are implicated in bladder disorders including overactive bladder (OAB) and BPS/IC. TRPV4 channels are strong candidates for mechanosensors in the urinary bladder and TRPV4 antagonists are promising therapeutic agents for OAB. In this perspective piece, we address the current knowledge of TRPV4 distribution and function in the LUT and its plasticity with injury or disease with an emphasis on BPS/IC. We review our studies that extend the knowledge of TRPV4 in urinary bladder function by focusing on (i) TRPV4 involvement in voiding dysfunction, pelvic pain, and non-voiding bladder contractions in NGF-OE mice; (ii) distention-induced luminal ATP release mechanisms and (iii) involvement of TRPV4 and vesicular release mechanisms. Finally, we review our lamina propria studies in postnatal rat studies that demonstrate: (i) the predominance of the TRPV4+ and PDGFRα+ lamina propria cellular network in early postnatal rats; (ii) the ability of exogenous mediators (i.e., ATP, TRPV4 agonist) to activate and increase the number of lamina propria cells exhibiting active Ca2+ events; and (iii) the ability of ATP and TRPV4 agonist to increase the rate of integrated Ca2+ activity corresponding to coupled lamina propria network events and the formation of propagating wavefronts.

The Effect of Capsaicin on Neuroinflammatory Mediators of Rosacea.

BackgroundRosacea is a chronic inflammatory skin disease with a pathophysiological mechanism that remains unclear. Recently, dysregulation of the sensory nerve system has been implicated in the development of this condition.ObjectiveThis study aimed to investigate the effect of capsaicin on neuroinflammatory mediators in rosacea. In addition, this study aimed to evaluate the attenuating effects of capsazepine, a transient receptor potential vanilloid type 1 (TRPV1) antagonist.MethodsWe obtained skin tissue from both rosacea patients and normal individuals for an in vivo study. In addition, normal human epidermal keratinocytes (NHEKs) were cultured, and treated with capsaicin and capsazepine for an in vitro study. Quantitative changes in neuroinflammatory mediators were evaluated by semi-quantitative reverse transcription-polymerase chain reaction (PCR), real-time PCR, enzyme-linked immunosorbent assay, and immunofluorescence staining.ResultsThe data showed the increase of TRPV1, TRPV4, cathelicidin (LL37) and tumor necrosis factor-α (TNF-α) in skin tissue by real-time PCR. In addition, the data showed that cathelicidin (LL37), kallikrein-5 (KLK-5), TNF-α, vascular endothelial growth factor (VEGF), interleukin (IL)-1α, IL-1β, IL-8, and protease-activated receptor 2 (PAR2) increased in capsaicin-treated NHEKs. Capsazepine attenuated the expression of TRPV1 and other mediators, except for IL-8, in capsaicin-treated NHEKs.ConclusionWe confirmed that TRPV1, TRPV4, cathelicidin (LL37) and TNF-α are increased in rosacea skin, and that capsaicin is associated with increase of neuroinflammatory mediators such as LL37, KLK-5, TNF-α, VEGF, IL-1α, IL-1β, IL-8, and PAR2. Modulators or inhibitors of neuroinflammatory mediators including TRPV1 could be potential therapeutic option in the treatment of patients with rosacea.

The Emerging Pro-Algesic Profile of Transient Receptor Potential Vanilloid Type 4.

Transient receptor potential vanilloid type 4 (TRPV4) channels are Ca2+-permeable non-selective cation channels which mediate a wide range of physiological functions and are activated and modulated by a diverse array of stimuli. One of this ion channel's least discussed functions is in relation to the generation and maintenance of certain pain sensations. However, in the two decades which have elapsed since the identification of this ion channel, considerable data has emerged concerning its function in mediating pain sensations. TRPV4 is a mediator of mechanical hyperalgesia in the various contexts in which a mechanical stimulus, comprising trauma (at the macro-level) or discrete extracellular pressure or stress (at the micro-level), results in pain. TRPV4 is also recognised as constituting an essential component in mediating inflammatory pain. It also plays a role in relation to many forms of neuropathic-type pain, where it functions in mediating mechanical allodynia and hyperalgesia.Here, we review the role of TRPV4 in mediating pain sensations.

Roles of Cannabidiol in the Treatment and Prevention of Alzheimer's Disease by Multi-target Actions.

Alzheimer's Disease (AD) is one of the most common neurodegenerative diseases with chronic, progressive, and irreversible characteristics, affecting nearly 50 million older adults worldwide. The pathogenesis of AD includes the formation of senile plaques, the abnormal aggregation of tau protein and the gradual degeneration and death of cerebral cortical cells. The main symptoms are memory loss, cognitive decline and behavioral disorders. Studies indicate that cannabidiol (CBD) possesses various pharmacological activities, including anti-inflammatory, anti-oxidation and neuroprotective activities. It has been suggested as a potential multi-target medicine for the treatment of AD. In this review, we aim to summarize the underlying mechanisms and protective effects of CBD on signaling pathways and central receptors involved in the pathogenesis of AD, including the endocannabinoid system (eCBs), the Transient receptor potential vanilloid type 1(TRPV1) receptor, and the Peroxisome Proliferator-Activated Receptor (PPAR) receptor.

TRPV4-dependent signaling mechanisms in systemic and pulmonary vasculature.

The delicate balance between constrictor and dilator mechanisms is a vital determinant of blood pressure and blood flow. The maintenance of this balance requires constant communication between different cell-types in the vascular wall. In this regard, the transient receptor potential vanilloid type 4 (TRPV4) ion channel, a Ca2+-permeable non-selective cation channel, has emerged as a crucial regulator of Ca2+-mediated changes in vascular reactivity. Recent studies suggest that TRPV4 channels regulate vasoconstriction and arterial pressure in the systemic and pulmonary vasculature. New emerging data support a dilatory role of endothelial TRPV4 channels, and both constrictor and dilator roles of smooth muscle TRPV4 channels. Moreover, TRPV4 channel activity has been implicated in physiological functions of vascular support cells, such as fibroblasts and pericytes, to assist the sustenance of vascular reactivity in response to changes in intravascular pressure or external stimulation. Importantly, a growing body of evidence connects abnormal TRPV4 channel activity to multiple vascular disorders. This chapter will review the current literature on the cell-type specific roles of vascular TRPV4 channels in regulating physiological function. Additionally, we summarize our understanding of the contribution of abnormal TRPV4 channel activity to various vascular disorders.

Hypothermia Induced by Oxcarbazepine after Transient Forebrain Ischemia Exerts Therapeutic Neuroprotection through Transient Receptor Potential Vanilloid Type 1 and 4 in Gerbils.

In the present study, we investigated the neuroprotective effect of post-ischemic treatment with oxcarbazepine (OXC; an anticonvulsant compound) against ischemic injury induced by transient forebrain ischemia and its mechanisms in gerbils. Transient ischemia was induced in the forebrain by occlusion of both common carotid arteries for 5 min under normothermic conditions (37 ± 0.2 °C). The ischemic gerbils were treated with vehicle, hypothermia (whole-body cooling; 33.0 ± 0.2 °C), or 200 mg/kg OXC. Post-ischemic treatments with vehicle and hypothermia failed to attenuate and improve, respectively, ischemia-induced hyperactivity and cognitive impairment (decline in spatial and short-term memory). However, post-ischemic treatment with OXC significantly attenuated the hyperactivity and the cognitive impairment, showing that OXC treatment significantly reduced body temperature (to about 33 °C). When the hippocampus was histopathologically examined, pyramidal cells (principal neurons) were dead (lost) in the subfield Cornu Ammonis 1 (CA1) of the gerbils treated with vehicle and hypothermia on Day 4 after ischemia, but these cells were saved in the gerbils treated with OXC. In the gerbils treated with OXC after ischemia, the expression of transient receptor potential vanilloid type 1 (TRPV1; one of the transient receptor potential cation channels) was significantly increased in the CA1 region compared with that in the gerbils treated with vehicle and hypothermia. In brief, our results showed that OXC-induced hypothermia after transient forebrain ischemia effectively protected against ischemia–reperfusion injury through an increase in TRPV1 expression in the gerbil hippocampal CA1 region, indicating that TRPV1 is involved in OXC-induced hypothermia.

Capsaicin and TRPV1 Channels in the Cardiovascular System: The Role of Inflammation.

Capsaicin is a potent agonist of the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel and is a common component found in the fruits of the genus Capsicum plants, which have been known to humanity and consumed in food for approximately 7000–9000 years. The fruits of Capsicum plants, such as chili pepper, have been long recognized for their high nutritional value. Additionally, capsaicin itself has been proposed to exhibit vasodilatory, antimicrobial, anti-cancer, and antinociceptive properties. However, a growing body of evidence reveals a vasoconstrictory potential of capsaicin acting via the vascular TRPV1 channel and suggests that unnecessary high consumption of capsaicin may cause severe consequences, including vasospasm and myocardial infarction in people with underlying inflammatory conditions. This review focuses on vascular TRPV1 channels that are endogenously expressed in both vascular smooth muscle and endothelial cells and emphasizes the role of inflammation in sensitizing the TRPV1 channel to capsaicin activation. Tilting the balance between the beneficial vasodilatory action of capsaicin and its unwanted vasoconstrictive effects may precipitate adverse outcomes such as vasospasm and myocardial infarction, especially in the presence of proinflammatory mediators.

Mechanisms of Flow-Mediated Dilation of Pial Collaterals and the Effect of Hypertension.

Leptomeningeal anastomoses are small distal anastomotic vessels also known as pial collaterals in the brain. These vessels redirect blood flow during an occlusion and are important for stroke treatment and outcome. Pial collaterals have unique hemodynamic forces and experience significantly increased luminal flow and shear stress after the onset of ischemic stroke. However, there is limited knowledge of how pial collaterals respond to flow and shear stress, and whether this response is altered in chronic hypertension. Using an in vitro system, pial collaterals from normotensive and hypertensive rats (n=6-8/group) were isolated and luminal flow was induced with intravascular pressure maintained at 40 mm Hg. Collateral lumen diameter was measured following each flow rate in the absence or presence of pharmacological inhibitors and activators. Collaterals from male and female Wistar rats dilated similarly to increased flow (2 µL/minute: 58.4±18.7% versus 67.9±7.4%; P=0.275), and this response was prevented by inhibition of the transient receptor potential vanilloid type 4 channel, as well as inhibitors of nitric oxide and intermediate-conductance calcium-activated potassium channels, suggesting shear stress-induced activation of this pathway was involved. However, the vasodilation was significantly impaired in hypertensive rats (2 µL/minute: 17.7±7.7%), which was restored by inhibitors of reactive oxygen species and mimicked by angiotensin II. Thus, flow- and shear stress-induced vasodilation of pial collaterals appears to be an important stimulus for increasing collateral flow during large vessel occlusion. Impairment of this response during chronic hypertension may be related to poorly engaged pial collaterals during ischemic stroke in hypertensive subjects.

TRPV1 channel mediates NLRP3 inflammasome-dependent neuroinflammation in microglia

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease in the central nervous system (CNS). The NLRP3 inflammasome is considered an important regulator of immunity and inflammation, both of which play a critical role in MS. However, the underlying mechanism of NLRP3 inflammasome activation is not fully understood. Here we identified that the TRPV1 (transient receptor potential vanilloid type 1) channel in microglia, as a Ca2+ influx-regulating channel, played an important role in NLRP3 inflammasome activation. Deletion or pharmacological blockade of TRPV1 inhibited NLRP3 inflammasome activation in microglia in vitro. Further research revealed that TRPV1 channel regulated ATP-induced NLRP3 inflammasome activation through mediating Ca2+ influx and phosphorylation of phosphatase PP2A in microglia. In addition, TRPV1 deletion could alleviate mice experimental autoimmune encephalomyelitis (EAE) and reduce neuroinflammation by inhibiting NLRP3 inflammasome activation. These data suggested that the TRPV1 channel in microglia can regulate NLRP3 inflammasome activation and consequently mediate neuroinflammation. Meanwhile, our study indicated that TRPV1–Ca2+–PP2A pathway may be a novel regulator of NLRP3 inflammasome activation, pointing to TRPV1 as a potential target for CNS inflammatory diseases.

Animal models and experimental medicine and the Nobel Prize in Physiology or Medicine 2021-TRPV and PIEZO receptors for temperature and touch sensation.

Animal models and experimental medicine and the Nobel Prize in Physiology or Medicine 2021-TRPV and PIEZO receptors for temperature and touch sensation.

Overexpression of microRNA-135b-5p attenuates acute myocardial infarction injury through its anti-oxidant and anti-apptotic properties

Abstract Objective Myocardial infarction (MI) remains the leading cause of morbidity and mortality due partly to the limited regenerative capacity of cardiomyocytes to replace cardiomyocyte lost due to apoptosis. Inhibiting cardiomyocyte apoptosis is recognized as an effective therapeutic approach for MI. MicroRNAs (miRNAs, miRs), which regulate target genes at the post-transcriptional level, play a significant role in the regulation of cardiovascular diseases such as MI. MicroRNA-135b (miR-135b) has a protective effect on cardiomyocytes. However, the role of miR-135b in cardiomyocyte apoptosis in infarct myocardium needs further clarification. Methods We generated α-MHC-miR-135b transgenic mice to investigate the role of miR-135b in myocardial injury after MI. MiR-135b mimic and negative control (NC) were transfected into H2O2-induced cardiomyocytes to evaluate the effect of overexpression of miR-135b on the levels of reactive oxygen species (ROS) and apoptosis. Results Our results showed that overexpression of miR-135b had protective effect on cardiomyocyte injury both in vivo and in vitro. MiR-135b inhibited cardiomyocyte apoptosis and ROS generation, downregulated proapoptosis proteins (cleaved-caspase-3 and Bax), and increased anti-apoptosis protein (Bcl-2). Moreover, miR-135b showed an inhibitory effect on apoptosis-related protein target transient receptor potential vanilloid-type 4 (TRPV4) cation channel. Conclusion MiR-135b might be considered a new molecular target for potential replacement therapy as antiapoptotic cardioprotection in the setting of MI.

Peripherally administered cannabinoid receptor 2 (CB2R) agonists lose anti-allodynic effects in TRPV1 knockout mice, while intrathecal administration leads to anti-allodynia and reduced GFAP, CCL2 and TRPV1 expression in the dorsal spinal cord and DRG

The transient receptor potential (TRP) superfamily of cation channels, of which the TRP vanilloid type 1 (TRPV1) receptor plays a critical role in inflammatory and neuropathic pain, is expressed on nociceptors and spinal cord dorsal horn neurons. TRPV1 is also expressed on spinal astrocytes and dorsal root ganglia (DRG) satellite cells. Agonists of the cannabinoid type 2 receptor (CB2R) suppress allodynia, with some that can bind TRPV1. The neuroimmune C–C class chemokine-2 (CCL2) expressed on injured DRG nociceptor cell bodies, Schwann cells and spinal astrocytes, stimulates immune cell accumulation in DRG and spinal cord, a known critical element in chronic allodynia. The current report examined whether two CB2R agonists, AM1710 and AM1241, previously shown to reverse light touch mechanical allodynia in rodent models of sciatic neuropathy, require TRPV1 activation that leads to receptor insensitivity resulting in reversal of allodynia. Global TRPV1 knockout (KO) mice with sciatic neuropathy given intrathecal or intraperitoneal AM1710 were examined for anti-allodynia followed by immunofluorescent microscopy analysis of lumbar spinal cord and DRG of astrocyte and CCL2 markers. Additionally, immunofluorescent analysis following intrathecal AM1710 and AM1241 in rat was performed. Data reveal that intrathecal AM1710 resulted in mouse anti-allodynia, reduced spinal astrocyte activation and CCL2 expression independent of TRPV1 gene deletion. Conversely, peripheral AM1710 in TRPV1-KO mice failed to reverse allodynia. In rat, intrathecal AM1710 and AM1241 reduced spinal and DRG TRPV1 expression, with CCL2-astrocyte and -microglial co-expression. These data support that CB2R agonists can impact spinal and DRG TRPV1 expression critical for anti-allodynia.

Capsaicin restores sodium iodine symporter-mediated radioiodine uptake through bypassing canonical TSH‒TSHR pathway in anaplastic thyroid carcinoma cells.

Anaplastic thyroid cancer (ATC) is a rare but highly lethal disease. ATCs are resistant to standard therapies and are extremely difficult to manage. The stepwise cell dedifferentiation results in the impairment of the iodine-metabolizing machinery and the infeasibility of radioiodine treatment in ATC. Hence, reinducing iodine-metabolizing gene expression to restore radioiodine avidity is considered as a promising strategy to fight against ATC. In the present study, capsaicin (CAP), a natural potent transient receptor potential vanilloid type 1 (TRPV1) agonist, was discovered to reinduce ATC cell differentiation and to increase the expression of thyroid transcription factors (TTFs including TTF-1, TTF-2, and PAX8) and iodine-metabolizing proteins, including thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase, and sodium iodine symporter (NIS), in two ATC cell lines, 8505C and FRO. Strikingly, CAP treatment promoted NIS glycosylation and its membrane trafficking, resulting in a significant enhancement of radioiodine uptake of ATC cells in vitro. Mechanistically, CAP-activated TRPV1 channel and subsequently triggered Ca2+ influx, cyclic adenosine monophosphate (cAMP) generation, and cAMP-responsive element-binding protein (CREB) signal activation. Next, CREB recognized and bound to the promoter of SLC5A5 to facilitate its transcription. Moreover, the TRPV1 antagonist CPZ, the calcium chelator BAPTA, and the PKA inhibitor H-89 effectively alleviated the redifferentiation exerted by CAP, demonstrating that CAP might improve radioiodine avidity through the activation of the TRPV1‒Ca2+/cAMP/PKA/CREB signaling pathway. In addition, our study indicated that CAP might trigger a novel cascade to redifferentiate ATC cells and provide unprecedented opportunities for radioiodine therapy in ATC, bypassing canonical TSH‒TSHR pathway.

Recent advances in understanding ion transport mechanisms in polycystic kidney disease.

This review focuses on the most recent advances in the understanding of the electrolyte transport-related mechanisms important for the development of severe inherited renal disorders, autosomal dominant (AD) and recessive (AR) forms of polycystic kidney disease (PKD). We provide here a basic overview of the origins and clinical aspects of ARPKD and ADPKD and discuss the implications of electrolyte transport in cystogenesis. Special attention is devoted to intracellular calcium handling by the cystic cells, with a focus on polycystins and fibrocystin, as well as other calcium level regulators, such as transient receptor potential vanilloid type 4 (TRPV4) channels, ciliary machinery, and purinergic receptor remodeling. Sodium transport is reviewed with a focus on the epithelial sodium channel (ENaC), and the role of chloride-dependent fluid secretion in cystic fluid accumulation is discussed. In addition, we highlight the emerging promising concepts in the field, such as potassium transport, and suggest some new avenues for research related to electrolyte handling.

WSF-CT-11, a Sesquiterpene Derivative, Activates AMP-Activated Protein Kinase with Anti-diabetic Effects in 3T3-L1 Adipocytes

Background: AMP-activated protein kinase (AMPK) is a therapeutic target against type II diabetes (T2D). Synthetic sesquiterpene derivatives were investigated to identify novel AMPK activators as anti-diabetic drugs because the leading drugs like metformin and thiazolidinediones (TZDs) activate AMPK by inhibiting the synthesis of adenosine 5′-triphosphate and thus are associated with some side effects. Results: We identified WSF-CT-11 as an AMPK activator in HEK293T cells and found that WSF-CT-11 activates AMPK by the activation of transient receptor potential vanilloid type 1 (TRPV1), a Ca2+-permeable cation channel. The increased Ca2+ influx then activates phosphoinositide 3-kinase (PI3K), protein kinase B (PKB/Akt), and Ca2+/calmodulin-dependent protein kinase II (CaMKII), which in turn phosphorylates TRPV1 and facilitates the formation of a TRPV1/Akt/CaMKII/AMPK complex. This complex might be important for the regulation of AMPK activity. In 3T3-L1 adipocytes, WSF-CT-11-induced AMPK activation has three anti-diabetic effects. It promotes the assembly of high-molecular-weight adiponectin, which has stronger insulin-sensitizing activity than other multimers. It improves translocation of the glucose transporter type 4, increases glucose uptake, and induces the inhibitory phosphorylation of peroxisome proliferator-activated receptor γ and thus suppresses adipogenesis. Conclusion: WSF-CT-11 is a novel AMPK activator and potential drug against T2D without the side effects of metformin and TZDs.

Cellular distribution of cannabinoid-related receptors TRPV1, PPAR-gamma, GPR55 and GPR3 in the equine cervical dorsal root ganglia.

BackgroundThe activation of cannabinoid and cannabinoid‐related receptors by endogenous, plant‐derived or synthetic cannabinoids may exert beneficial effects on pain perception. Of the cannabinoids contained in Cannabis sativa, cannabidiol (CBD) does not produce psychotropic effects and seems to represent a molecule having great therapeutic potential. Cannabidiol acts on a great number of cannabinoid and cannabinoid‐related G‐protein‐coupled receptors and ionotropic receptors which have, to date, been understudied in veterinary medicine particularly in equine medicine.ObjectivesTo localise the cellular distribution of four putative cannabinoid‐related receptors in the equine cervical dorsal root ganglia (DRG).Study designA qualitative and quantitative immunohistochemical study.MethodsThe cervical (C6‐C8) DRG of six slaughtered horses were obtained from a local slaughterhouse. The tissues were fixed and processed for immunohistochemistry, and the resulting cryosections were used to investigate immunoreactivity for the following putative CBD receptors: Transient receptor potential vanilloid type 1 (TRPV1), nuclear peroxisome proliferator‐activated receptor gamma (PPARγ), and G protein‐coupled receptors 55 (GPR55) and 3 (GPR3).ResultsLarge percentages of neuronal cell bodies showed immunoreactivity for TRPV1 (80 ± 20%), PPARγ (100%), GPR55 (64 ± 15%) and GPR3 (63 ± 11%). The satellite glial cells (SGCs) were immunoreactive for TRPV1, PPARγ and GPR55. In addition, GPR55 immunoreactivity was expressed by DRG interneuronal macrophages. In addition, microglia cells were observed surrounding the neuron–SGC complex.Main limitationsThe limited number of horses included in the study.ConclusionsCannabinoid‐related receptors were distributed in the sensory neurons (TRPV1, PPARγ, GPR55 and GPR3), SGCs (TRPV1, PPARγ and GPR55), macrophages (GPR55) and other interneuronal cells (PPARγ and GPR55) of the equine DRG. Given the key role of DRG cellular elements and cannabinoid receptors in the pathophysiology of pain, the present findings provided an anatomical basis for additional studies aimed at exploring the therapeutic uses of non‐psychotropic cannabinoid agonists for the management of pain in horses.

Abstract MP48: Crispr/cas9 Trpv1 Deletion In Rats Does Not Impair Mechano- And Chemo-sensory Renal Afferent Nerve Responses

Elevated renal afferent nerve activity (ARNA) or dysfunctional renal reflexes contributes to hypertension and chronic kidney disease. The transient receptor potential vanilloid type-1 (TRPV1) channel is expressed in renal sensory nerves, and intrarenal administration of the TRPV1 agonist capsaicin increases ARNA. Nonselective denervation of renal sensory nerves using high-concentration capsaicin reduces arterial blood pressure (ABP) in experimental models of hypertension. However, the role of TRPV1 channels in ARNA responses to chemo- and mechano-sensitive stimuli has not been directly tested. To test this hypothesis, we generated a novel TRPV1 rat knockout model (TRPV1 -/- ) using CRISPR/CAS9 to delete exon 3 . ARNA multifiber recordings were performed in male and female TRPV1 -/- and wild-type littermates (250-400g) after decerebration or Inactin anesthesia (data combined). Wild-type and TRPV1 -/- rats had no significant differences in baseline mean ABP (126±4 mmHg vs 138±5 mmHg, respectively; n=8-10) or heart rate (451±25 bpm vs 432±24 bpm, respectively; n=8-10). Baseline ARNA was not different between wild-type and TRPV1 -/- rats (16±3 Hz vs 28±6 Hz, respectively; n=8-10). Intrarenal artery infusion of the TRPV1 agonist capsaicin (0.1-10μM, 50μL per 15s) significantly increased ipsilateral ARNA in wild-type but not TRPV1 -/- rats (Δ discharge with 10μM: 65±3 Hz vs 6±1 Hz, respectively; n=5-7). As a second chemosensitive stimulus, intrarenal artery infusion of bradykinin (0.1-10μM, 50μL per 15s) produced similar increases in ipsilateral ARNA between wild-type and TRPV1 -/- rats (Δ discharge with 10μM: 52±6 Hz vs 73±18 Hz, respectively; n=5-6). Finally, elevated renal pelvic pressures (0-20mmHg; 30s) significantly increased ipsilateral ARNA in both wild-type and TRPV1 -/- rats; however, the ARNA response was significantly greater in TRPV1 -/- versus wild-type rats (Δ discharge with 20mmHg: 47±14 Hz versus 18±6 Hz, respectively; n=5-8). In conclusion, mechanosensitive and chemosensitive ARNA responses remain intact in TRPV1 -/- rats. The mechanisms responsible for renal sensory nerve activation remain unidentified and the impact of TRPV1 deletion in rat models of hypertension and kidney disease remains to be tested.