Transient Receptor Potential Melastatin 8 Channel (TRPM8) Modulation: Cool Entryway for Treating Pain and Cancer

TRPM8 ion channels, the primary cold sensors in humans, are activated by innocuous cooling (<28 °C) and cooling compounds (menthol, icilin) and are implicated in sensing unpleasant cold stimuli as well as in mammalian thermoregulation. Overexpression of these thermoregulators in prostate cancer and in other life-threatening tumors, along with their contribution to an increasing number of pathological conditions, opens a plethora of medicinal chemistry opportunities to develop receptor modulators. This Perspective seeks to describe current known modulators for this ion channel because both agonists and antagonists may be useful for the treatment of most TRPM8-mediated pathologies. We primarily focus on SAR data for the different families of compounds and the pharmacological properties of the most promising ligands. Furthermore, we also address the knowledge about the channel structure, although still in its infancy, and the role of the TRPM8 protein signalplex to channel function and dysfunction. We finally outline the potential future prospects of the challenging TRPM8 drug discovery fieldWe thank Gregorio Fernández-Ballester for the figure of the TRPM8 homology model. Funding from the Ministry of Economy and Competitiveness (BFU 2012-39092-C02; SAF2015-66275-C2-R) and the Generalitat Valenciana (PROMETEO II/2014/011).Peer reviewe

Anticancer Effect of Capsaicin and Its Analogues

Potent biomolecules from natural products from plants, animals, and minerals are the fundamental basis of the ailment of mankind. Capsicum or red pepper plants were grouped under the kingdom Plantae and family Solanaceae. It is used widely throughout the world in foods for their pungent flavor and aroma, and to prolong food spoilage. This chapter presents a frame of a concise compilation of the anticancer and cytotoxic potentials of Capsicum, its analogs, and related compounds. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the most predominant and naturally occurring alkaloid from the Capsicum species. It also details the anticancer efficacy of capsaicin and its analogs like capsaicinoids and capsiates which possess antioxidants and targets multiple signaling pathways, ontogenesis, and tumor-suppressor genes in various types of cancer models. Capsaicin is a major ingredient and has been linked to suppression of growth in various cancer cells. The data available strongly indicate the significant anticancer benefits of capsaicin and its potent analog molecules. It shows a significant effect on cancer cell proliferation, apoptosis, cancer cell surveillance, growth arrest, and metastasis. This chapter also predominantly focuses on the combinational use of capsaicin with other natural dietary compounds as a measure of synergistic anticancer activities

Elongation of the Hydrophobic Chain as a Molecular Switch:Discovery of Capsaicin Derivatives and Endogenous Lipids as Potent Transient Receptor Potential Vanilloid Channel 2 Antagonists

The transient receptor potential vanilloid type-2 (TRPV2) protein is a nonselective Ca2+ permeable channel member of the TRPV subfamily, still considered an orphan TRP channel due to the scarcity of available selective and potent pharmacological tools and endogenous modulators. Here we describe the discovery of novel synthetic long-chain capsaicin derivatives as potent TRPV2 antagonists in comparison to the totally inactive capsaicin, the role of their hydrophobic chain, and how the structure-activity relationships of such derivatives led, through a ligand-based approach, to the identification of endogenous long-chain fatty acid ethanolamides or primary amides acting as TRPV2 antagonists. Both synthetic and endogenous antagonists exhibited differential inhibition against known TRPV2 agonists characterized by distinct kinetic profiles. These findings represent the first example of both synthetic and naturally occurring TRPV2 modulators with efficacy in the submicromolar/low-micromolar range, which will be useful for clarifying the physiopathological roles of this receptor, its regulation, and its targeting in pathological conditions.We gratefully acknowledge financial support from Universitat de Lleida, Ministerio de Educación, Cultura y Deporte and Banco Santander (Programa UdL-Impuls). The authors are grateful to the Serveis Cientifictècnics (SCT) of the Universitat de Lleida for providing us with spectroscopic and chromatographic facilities. We acknowledge Dr. Alberto Minassi, Dipartimento di Scienze del Farmaco, Universitàdel Piemonte Orientale, Novara, Italy, for the kind gift of olvanil

IN SILICO SCREENING OF TASTE RECEPTORS: AN INTEGRATE MODELING APPROACH.

Taste is one of the five senses and accounts for the sensory impression of food or other substances on the tongue. It represents an innate mechanism of defence by which humans and animals detect safety or threat in food. Notably, taste is a whole-body experience since taste receptors, besides being located in the taste buds, are also found in non-sensory tissues, like the gut or the airways, playing still not completely known roles, for example, in glucose metabolism as well as in energy homeostasis. This clearly lays the groundwork for scientific investigations aimed to develop chemical tools through which modulate these physiopathological mechanisms. Although both GPCR and Ion Channels mediate these processes, this Thesis focuses on the latter class, so far less explored than the former one, involving four members of the Transient Potential Receptors family, namely TRPM8, TRPM5, TRPV1 and TRPV4. Although if each study presented its own objectives, peculiarities and relative computational approaches, a common path can be traced for all of them. First, the three-dimensional structure was generated by homology modelling techniques, by exploiting a well validated fragmental approach, then the obtained homology model was tested by docking calculations, which while including preliminary correlative studies, were always aimed at developing reliable strategies for virtual screening campaigns. The here reported results provide further remarkable confirmations for the reliability of the already modelled (and exploited) TRPM8 model, while the here generated TRPM5 and TRPV4 models afford results (despite obtained in a validating preliminary phase) in line with those of TRPM8 further emphasizing the reliability of the fragmental approach. Not to mention that the described targeted strategy to model TRPV1 suggests that previously generated homology models can be then exploited to assist the modeling of highly homologous proteins still obtaining encouraging results but with a significant saving of the required computational efforts. Finally, the here proposed TRPM8 results offer a convincing proof of the potential improvements that may be obtained combining ligand-based and structure-based approaches in a virtual screening analysis

A journey from molecule to physiology and in silico tools for drug discovery targeting the transient receptor potential vanilloid type 1 (TRPV1) channel

The heat and capsaicin receptor TRPV1 channel is widely expressed in nerve terminals of dorsal root ganglia (DRGs) and trigeminal ganglia innervating the body and face, respectively, as well as in other tissues and organs including central nervous system. The TRPV1 channel is a versatile receptor that detects harmful heat, pain, and various internal and external ligands. Hence, it operates as a polymodal sensory channel. Many pathological conditions including neuroinflammation, cancer, psychiatric disorders, and pathological pain, are linked to the abnormal functioning of the TRPV1 in peripheral tissues. Intense biomedical research is underway to discover compounds that can modulate the channel and provide pain relief. The molecular mechanisms underlying temperature sensing remain largely unknown, although they are closely linked to pain transduction. Prolonged exposure to capsaicin generates analgesia, hence numerous capsaicin analogs have been developed to discover efficient analgesics for pain relief. The emergence of in silico tools offered significant techniques for molecular modeling and machine learning algorithms to indentify druggable sites in the channel and for repositioning of current drugs aimed at TRPV1. Here we recapitulate the physiological and pathophysiological functions of the TRPV1 channel, including structural models obtained through cryo-EM, pharmacological compounds tested on TRPV1, and the in silico tools for drug discovery and repositioning

Búsqueda racional y análisis de actividad biológica de nuevos activadores del canal TRPV1, análogos a capsaicina

Tesis (Magíster en Biotecnología)Proyecto FONDECYT Regular 1131003La supervivencia de un organismo está directamente relacionada con su capacidad de percibir e interpretar de manera adecuada su entorno. Esta tarea es realizada por el sistema nervioso mediante la activación de un subgrupo de neuronas sensoriales primarias, las que interpretan estos estímulos, transformándolos en impulsos nerviosos. Cuando un estímulo de naturaleza química, mecánica o térmica supera un umbral de intensidad definido, se genera una respuesta dolorosa aguda, proceso conocido como nocicepción. Durante décadas se utilizó a capsaicina, compuesto picante del ají, como agente farmacológico específico para la caracterización funcional de terminales sensoriales primarios. Su actividad selectiva sugería la existencia de un receptor específico para este compuesto, lográndose la identificación de un canal relacionado a la familia de canales de potencial transiente (TRP) a partir de células del ganglio de la raíz dorsarl (DRG) de rata. Los receptores de potencial transiente o TRP se encuentran involucrados en procesos de transducción sensorial de prácticamente todos los organismos multicelulares, siendo el canal TRPV1 el primer miembro de esta familia en ser asociado a procesos de generación de dolor. La modulación de la actividad del canal por antagonistas y la insensibilización por la aplicación de agonistas de alta potencia, ha mostrado ser una estrategia efectiva para el tratamiento del dolor, pero no han sido fructíferas debido a los efectos adversos presentados en los individuos tratados. Esto abre la necesidad de la identificación mediante estrategias de búsqueda racional de nuevas moléculas, las que puedan servir como pistas para el desarrollo de terapias analgésicas mas eficaces y seguras. De este modo, tomando ventaja de las estructuras tridimensionales del canal TRPV1 publicadas, el presente estudio pretende aprovechar el poder de cómputo disponible para así aventurarnos en el desarrollo de una estrategia computacional, soportada con validación experimental, para la identificación de nuevos activadores del canal TRPV1 con el fin de aportar con nuevos compuestos líderes, más potentes que capsaicina, como punto de partida para la generación de nuevas terapias analgésicas. Además, mediante la caracterización de los determinantes moleculares que median la interacción de ligandos agonistas con el canal, se espera continuar contribuyendo al entendimiento sobre el mecanismo de activación dependiente de ligando del canal TRPV1.An organism survival is directly influenced by its capacity to perceive and interpret its surroundings in an adequate way. This task is performed by the nervous system, by activating a subgroup of primary sensory neurons, which interpret those stimuli, transforming them in an action potential. When a stimulus of chemical, mechanical or thermal nature surpasses a threshold of determined intensity it generates an acute pain response, process known as nociception. Capsaicin, the pungent compound of chili peppers, has been used for decades as a specific pharmacological agent for the functional characterization of primary sensory terminals. Its selective activity suggested the existence of a specific receptor for this compounds, allowing researchers to identify an ion channel related to the transient receptor potential (TRP) family from rat dorsal root ganglion (DRG) cells. The transient potential receptors or TRPs are involved in processes of sensory transduction in practically all multicellular organisms, being the TRPV1 ion channel the first member of this family to be associated to pain generation processes. Modulation of the channel`s activity by antagonists and insensitivity by high potency agonists has shown to be an effective strategy for pain alleviation, but hasn`t been fruitful due to the adverse effects seen in the treated individuals. This opens the necessity of identifying new molecules that could be leads for the development of more efficient and safer analgesic therapies through rational search strategies. In this way, using the tridimensional structures of the TRPV1 ion channel publicly available, this study aims to take advantage of the available computing capacity to adventure ourselves in the development of a computational strategy supported by an experimental validation for the identification of new activators of the TRPV1 ion channel to contribute with new leader compounds, more powerful than capsaicin, as starting points for generating new analgesic therapies. In addition, we hope to continue contributing to the understanding about the ligand dependent activation mechanism of the ion channel TRPV1 through the characterization of the molecular determinants that mediate the interaction of agonist ligands with the ion channel

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.2

The TRP superfamily of channels (nomenclature as agreed by NC-IUPHAR [176, 1072]), whose founder member is the Drosophila Trp channel, exists in mammals as six families; TRPC, TRPM, TRPV, TRPA, TRPP and TRPML based on amino acid homologies. TRP subunits contain six putative TM domains and assemble as homo- or hetero-tetramers to form cation selective channels with diverse modes of activation and varied permeation properties (reviewed by [730]). Established, or potential, physiological functions of the individual members of the TRP families are discussed in detail in the recommended reviews and in a number of books [401, 686, 1155, 256]. The established, or potential, involvement of TRP channels in disease [1126] is reviewed in [448, 685], [688] and [464], together with a special edition of Biochemica et Biophysica Acta on the subject [685]. Additional disease related reviews, for pain [633], stroke [1135], sensation and inflammation [988], itch [130], and airway disease [310, 1051], are available. The pharmacology of most TRP channels has been advanced in recent years. Broad spectrum agents are listed in the tables along with more selective, or recently recognised, ligands that are flagged by the inclusion of a primary reference. See Rubaiy (2019) for a review of pharmacological tools for TRPC1/C4/C5 channels [805]. Most TRP channels are regulated by phosphoinostides such as PtIns(4,5)P2 although the effects reported are often complex, occasionally contradictory, and likely to be dependent upon experimental conditions, such as intracellular ATP levels (reviewed by [1009, 689, 801]). Such regulation is generally not included in the tables.When thermosensitivity is mentioned, it refers specifically to a high Q10 of gating, often in the range of 10-30, but does not necessarily imply that the channel's function is to act as a 'hot' or 'cold' sensor. In general, the search for TRP activators has led to many claims for temperature sensing, mechanosensation, and lipid sensing. All proteins are of course sensitive to energies of binding, mechanical force, and temperature, but the issue is whether the proposed input is within a physiologically relevant range resulting in a response. TRPA (ankyrin) familyTRPA1 is the sole mammalian member of this group (reviewed by [293]). TRPA1 activation of sensory neurons contribute to nociception [414, 890, 602]. Pungent chemicals such as mustard oil (AITC), allicin, and cinnamaldehyde activate TRPA1 by modification of free thiol groups of cysteine side chains, especially those located in its amino terminus [575, 60, 365, 577]. Alkenals with &#945;, &#946;-unsaturated bonds, such as propenal (acrolein), butenal (crotylaldehyde), and 2-pentenal can react with free thiols via Michael addition and can activate TRPA1. However, potency appears to weaken as carbon chain length increases [26, 60]. Covalent modification leads to sustained activation of TRPA1. Chemicals including carvacrol, menthol, and local anesthetics reversibly activate TRPA1 by non-covalent binding [424, 511, 1081, 1080]. TRPA1 is not mechanosensitive under physiological conditions, but can be activated by cold temperatures [425, 212]. The electron cryo-EM structure of TRPA1 [740] indicates that it is a 6-TM homotetramer. Each subunit of the channel contains two short &#8216;pore helices&#8217; pointing into the ion selectivity filter, which is big enough to allow permeation of partially hydrated Ca2+ ions. TRPC (canonical) familyMembers of the TRPC subfamily (reviewed by [284, 778, 18, 4, 94, 446, 739, 70]) fall into the subgroups outlined below. TRPC2 is a pseudogene in humans. It is generally accepted that all TRPC channels are activated downstream of Gq/11-coupled receptors, or receptor tyrosine kinases (reviewed by [765, 953, 1072]). A comprehensive listing of G-protein coupled receptors that activate TRPC channels is given in [4]. Hetero-oligomeric complexes of TRPC channels and their association with proteins to form signalling complexes are detailed in [18] and [447]. TRPC channels have frequently been proposed to act as store-operated channels (SOCs) (or compenents of mulimeric complexes that form SOCs), activated by depletion of intracellular calcium stores (reviewed by [741, 18, 770, 820, 1121, 157, 726, 64, 158]). However, the weight of the evidence is that they are not directly gated by conventional store-operated mechanisms, as established for Stim-gated Orai channels. TRPC channels are not mechanically gated in physiologically relevant ranges of force. All members of the TRPC family are blocked by 2-APB and SKF96365 [347, 346]. Activation of TRPC channels by lipids is discussed by [70]. Important progress has been recently made in TRPC pharmacology [805, 619, 436, 102, 851, 191, 291]. TRPC channels regulate a variety of physiological functions and are implicated in many human diseases [295, 71, 885, 1031, 1025, 154, 103, 561, 913, 409]. TRPC1/C4/C5 subgroup TRPC1 alone may not form a functional ion channel [229]. TRPC4/C5 may be distinguished from other TRP channels by their potentiation by micromolar concentrations of La3+. TRPC2 is a pseudogene in humans, but in other mammals appears to be an ion channel localized to microvilli of the vomeronasal organ. It is required for normal sexual behavior in response to pheromones in mice. It may also function in the main olfactory epithelia in mice [1114, 723, 724, 1115, 539, 1168, 1109].TRPC3/C6/C7 subgroup All members are activated by diacylglycerol independent of protein kinase C stimulation [347].TRPM (melastatin) familyMembers of the TRPM subfamily (reviewed by [275, 346, 741, 1151]) fall into the five subgroups outlined below. TRPM1/M3 subgroupIn darkness, glutamate released by the photoreceptors and ON-bipolar cells binds to the metabotropic glutamate receptor 6 , leading to activation of Go . This results in the closure of TRPM1. When the photoreceptors are stimulated by light, glutamate release is reduced, and TRPM1 channels are more active, resulting in cell membrane depolarization. Human TRPM1 mutations are associated with congenital stationary night blindness (CSNB), whose patients lack rod function. TRPM1 is also found melanocytes. Isoforms of TRPM1 may present in melanocytes, melanoma, brain, and retina. In melanoma cells, TRPM1 is prevalent in highly dynamic intracellular vesicular structures [398, 708]. TRPM3 (reviewed by [714]) exists as multiple splice variants which differ significantly in their biophysical properties. TRPM3 is expressed in somatosensory neurons and may be important in development of heat hyperalgesia during inflammation (see review [941]). TRPM3 is frequently coexpressed with TRPA1 and TRPV1 in these neurons. TRPM3 is expressed in pancreatic beta cells as well as brain, pituitary gland, eye, kidney, and adipose tissue [713, 940]. TRPM3 may contribute to the detection of noxious heat [1017]. TRPM2TRPM2 is activated under conditions of oxidative stress (respiratory burst of phagocytic cells). The direct activators are calcium, adenosine diphosphate ribose (ADPR) [970] and cyclic ADPR (cADPR) [1118]. As for many ion channels, PI(4,5)P2 must also be present [1109]. Numerous splice variants of TRPM2 exist which differ in their activation mechanisms [239]. Recent studies have reported structures of human (hs) TRPM2, which demonstrate two ADPR binding sites in hsTRPM2, one in the N-terminal MHR1/2 domain and the other in the C-terminal NUDT9-H domain. In addition, one Ca2+ binding site in the intracellular S2-S3 loop is revealed and proposed to mediate Ca2+ binding that induces conformational changes leading the ADPR-bound closed channel to open [387, 1027]. Meanwhile, a quadruple-residue motif (979FGQI982) was identified as the ion selectivity filter and a gate to control ion permeation in hsTRPM2 [1120]. TRPM2 is involved in warmth sensation [848], and contributes to several diseases [76]. TRPM2 interacts with extra synaptic NMDA receptors (NMDAR) and enhances NMDAR activity in ischemic stroke [1164]. Activation of TRPM2 in macrophages promotes atherosclerosis [1165, 1147]. Moreover, silica nanoparticles induce lung inflammation in mice via ROS/PARP/TRPM2 signaling-mediated lysosome impairment and autophagy dysfunction [1028]. Recent studies have designed various compounds for their potential to selectively inhibit the TRPM2 channel, including ACA derivatives A23, and 2,3-dihydroquinazolin-4(1H)-one derivatives [1137, 1139]. TRPM4/5 subgroupTRPM4 and TRPM5 have the distinction within all TRP channels of being impermeable to Ca2+ [1072]. A splice variant of TRPM4 (i.e.TRPM4b) and TRPM5 are molecular candidates for endogenous calcium-activated cation (CAN) channels [327]. TRPM4 is active in the late phase of repolarization of the cardiac ventricular action potential. TRPM4 deletion or knockout enhances beta adrenergic-mediated inotropy [593]. Mutations are associated with conduction defects [404, 593, 879]. TRPM4 has been shown to be an important regulator of Ca2+ entry in to mast cells [993] and dendritic cell migration [52]. TRPM5 in taste receptor cells of the tongue appears essential for the transduction of sweet, amino acid and bitter stimuli [537] TRPM5 contributes to the slow afterdepolarization of layer 5 neurons in mouse prefrontal cortex [513]. Both TRPM4 and TRPM5 are required transduction of taste stimuli [246]. TRPM6/7 subgroupTRPM6 and 7 combine channel and enzymatic activities (&#8216;chanzymes&#8217;) [172]. These channels have the unusual property of permeation by divalent (Ca2+, Mg2+, Zn2+) and monovalent cations, high single channel conductances, but overall extremely small inward conductance when expressed to the plasma membrane. They are inhibited by internal Mg2+ at ~0.6 mM, around the free level of Mg2+ in cells. Whether they contribute to Mg2+ homeostasis is a contentious issue. PIP2 is required for TRPM6 and TRPM7 activation [810, 1077]. When either gene is deleted in mice, the result is embryonic lethality [413, 1065]. The C-terminal kinase region of TRPM6 and TRPM7 is cleaved under unknown stimuli, and the kinase phosphorylates nuclear histones [479, 480]. TRPM7 is responsible for oxidant- induced Zn2+ release from intracellular vesicles [3] and contributes to intestinal mineral absorption essential for postnatal survival [622]. The putative metal transporter proteins CNNM1-4 interact with TRPM7 and regulate TRPM7 channel activity [40, 467]. TRPM8Is a channel activated by cooling and pharmacological agents evoking a &#8216;cool&#8217; sensation and participates in the thermosensation of cold temperatures [63, 178, 224] reviewed by [1011, 562, 457, 649]. Direct chemical agonists include menthol and icilin[1086]. Besides, linalool can promote ERK phosphorylation in human dermal microvascular endothelial cells, down-regulate intracellular ATP levels, and activate TRPM8 [68]. Recent studies have found that TRPM8 has typical S4-S5 connectomes with clear selective filters and exowell rings [512], and have identified cryo-electron microscopy structures of mouse TRPM8 in closed, intermediate, and open states along the ligand- and PIP2-dependent gated pathways [1111]. Moreover, the last 36 amino acids at the carboxyl terminal of TRPM8 are key protein sequences for TRPM8's temperature-sensitive function [194]. TRPM8 deficiency reduced the expression of S100A9 and increased the expression of HNF4&#945; in the liver of mice, which reduced inflammation and fibrosis progression in mice with liver fibrosis, and helped to alleviate the symptoms of bile duct disease [556]. Channel deficiency also shortens the time of hypersensitivity reactions in migraine mouse models by promoting the recovery of normal sensitivity [12]. A cyclic peptide DeC&#8208;1.2 was designed to inhibit ligand activation of TRPM8 but not cold activation, which can eliminate the side effects of cold dysalgesia in oxaliplatin-treated mice without changing body temperature [9]. Analysis of clinical data shows that TRPM8-specific blockers WS12 can reduce tumor growth in colorectal cancer xenografted mice by reducing transcription and activation of Wnt signaling regulators and &#946;-catenin and its target oncogenes, such as C-Myc and Cyclin D1 [732]. TRPML (mucolipin) familyThe TRPML family [782, 1132, 775, 1084, 190] consists of three mammalian members (TRPML1-3). TRPML channels are probably restricted to intracellular vesicles and mutations in the gene (MCOLN1) encoding TRPML1 (mucolipin-1) cause the neurodegenerative disorder mucolipidosis type IV (MLIV) in man. TRPML1 is a cation selective ion channel that is important for sorting/transport of endosomes in the late endocytotic pathway and specifically, fission from late endosome-lysosome hybrid vesicles and lysosomal exocytosis [822]. TRPML2 and TRPML3 show increased channel activity in low luminal sodium and/or increased luminal pH, and are activated by similar small molecules [319, 147, 877]. A naturally occurring gain of function mutation in TRPML3 (i.e. A419P) results in the varitint waddler (Va) mouse phenotype (reviewed by [782, 690]). TRPP (polycystin) familyThe TRPP family (reviewed by [216, 214, 300, 1061, 374]) or PKD2 family is comprised of PKD2 (PC2), PKD2L1 (PC2L1), PKD2L2 (PC2L2), which have been renamed TRPP1, TRPP2 and TRPP3, respectively [1072]. It should also be noted that the nomenclature of PC2 was TRPP2 in old literature. However, PC2 has been uniformed to be called TRPP2 [345]. PKD2 family channels are clearly distinct from the PKD1 family, whose function is unknown. PKD1 and PKD2 form a hetero-oligomeric complex with a 1:3 ratio. [905]. Although still being sorted out, TRPP family members appear to be 6TM spanning nonselective cation channels. TRPV (vanilloid) familyMembers of the TRPV family (reviewed by [995]) can broadly be divided into the non-selective cation channels, TRPV1-4 and the more calcium selective channels TRPV5 and TRPV6. TRPV1-V4 subfamilyTRPV1 is involved in the development of thermal hyperalgesia following inflammation and may contribute to the detection of noxius heat (reviewed by [762, 882, 922]). Numerous splice variants of TRPV1 have been described, some of which modulate the activity of TRPV1, or act in a dominant negative manner when co-expressed with TRPV1 [844]. The pharmacology of TRPV1 channels is discussed in detail in [329] and [1015]. TRPV2 is probably not a thermosensor in man [736], but has recently been implicated in innate immunity [547]. Functional TRPV2 expression is described in placental trophoblast cells of mouse [204]. TRPV3 and TRPV4 are both thermosensitive. There are claims that TRPV4 is also mechanosensitive, but this has not been established to be within a physiological range in a native environment [127, 530]. TRPV5/V6 subfamily TRPV5 and TRPV6 are highly expressed in placenta, bone, and kidney. Under physiological conditions, TRPV5 and TRPV6 are calcium selective channels involved in the absorption and reabsorption of calcium across intestinal and kidney tubule epithelia (reviewed by [1057, 205, 651, 270]).TRPV6 is reported to play a key role in calcium transport in the mouse placenta [1056]

TRP ACTIVE COMPOUNDS FROM FOOD PLANTS AND THEIR PROPERTIES AS ANTIMICROBIAL AND BIOCIDES

Nowadays plant derived compounds constitute a promising resource in ecofriendly pest and diseases management because they are \u2018generally recognized as safe\u2019 (GRAS). Plants have evolved ingenious defense mechanisms by production of pungent and irritant compounds. These substances produce their psychophysical effects by targeting the TRPA1 receptor, belonging to transient receptor potential (TRP) channels. Two secondary metabolites contained in the Asian food plant Perilla frutescens, perillaldehyde (PA) and perillaketone (PK), are potent agonists of TRPA1. The aim of the present PhD project was to determine the antimicrobial activity of the crude extracts and essential oils from the leaves of two Perilla frutescens varieties grown experimentally in Northern Italy. Commercial PA and PK, obtained by chemical synthesis, were also assayed in vitro and in vivo (PA, only). In addition, the nematicidal efficacy of pure PK was evaluated against 2nd instar larvae juveniles of cyst nematode Heterodera daverti. Chemical analysis allowed the identification of PA and PK as the main constituents in the two investigated cultivars respectively, and the consequent classification in PA and PK chemotypes. The organic extracts PA and PK-type (PA-Ex and PK-Ex) and the essential oils PA and PK type (PA-EO and PK-EO) exhibited a broad spectrum of activity against tested phytopatogenic organisms. The antibacterial activity of the tested substances resulted generally scanty. In vitro antifungal activity varied according to compound and target species. The essential oils appeared to be significantly more active compared with the crude extracts. At 500 \ub5g mL-1 PA-EO showed fungicidal activity against several fungi while PK-EO exhibited a fungistatic one. Both oils and commercial PA displayed high inhibition on Cladosporium cladosporoides IPV-F167 spore germination, while PA-Ex and pure PA proved good preventive activity reducing powdery mildew disease on cucumber plants. Besides, P. frutescens demonstrated to possess efficient nematicidal activity due to PK

Major v. Security Equipment Corp. Clerk\u27s Record v. 2 Dckt. 39414

https://digitalcommons.law.uidaho.edu/idaho_supreme_court_record_briefs/2188/thumbnail.jp