RESUMO
BACKGROUND: Lead is a toxic metal abundant in the environment. Consumption of food contaminated at low levels of lead, especially by small children and pregnant women, raises a health concern. METHODS: Duplicated food portions and drinking water were collected over 3 days from 88 children and 87 pregnant women in Shimotsuke, Tochigi, Japan. Participants were recruited in this study between January 2014 and October 2015. Dust was also collected from their homes. Lead concentrations were measured and consequent oral lead exposure levels were estimated for this population at high risk to environmental toxicants. Lead concentrations of peripheral and cord blood, taken from children and pregnant women, and were also analyzed. RESULTS: Lead concentrations in food, drinking water, and house dust were low in general. Oral lead exposure to lead was higher for children (Mean ± SEM; 5.21 ± 0.30 µg/kg BW/week) than in pregnant women (1.47 ± 0.13 µg/kg BW/week). Food and house dust were main sources of lead contamination, but the contribution of house dust widely varied. Means ± SEM of peripheral and cord blood lead concentrations were 0.69 ± 0.04 µg/dL and 0.54 ± 0.05 µg/dL, respectively for pregnant women and 1.30 ± 0.07 µg/dL (peripheral only) in children. We detect no correlation between smoking situations and blood lead concentration in pregnant women. CONCLUSION: We conclude that oral lead exposure levels for Japanese children and pregnant women were generally low, with higher concentrations and exposure for children than for pregnant women. More efforts are necessary to clarify the sources of lead contamination and reduce lead exposure of the population at high risk even in Japan.
Assuntos
Exposição Dietética/análise , Poeira/análise , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Chumbo/análise , Adulto , Pré-Escolar , Água Potável/análise , Poluentes Ambientais/sangue , Feminino , Sangue Fetal/química , Humanos , Lactente , Japão , Chumbo/sangue , Masculino , Gravidez , Adulto JovemRESUMO
The oral cavity provides an entrance to the alimentary tract to serve as a protective barrier against harmful environmental stimuli. The oral mucosa is susceptible to injury because of its location; nonetheless, it has faster wound healing than the skin and less scar formation. However, the molecular pathways regulating this wound healing are unclear. Here, we show that transient receptor potential vanilloid 3 (TRPV3), a thermosensitive Ca(2+)-permeable channel, is more highly expressed in murine oral epithelia than in the skin by quantitative RT-PCR. We found that temperatures above 33°C activated TRPV3 and promoted oral epithelial cell proliferation. The proliferation rate in the oral epithelia of TRPV3 knockout (TRPV3KO) mice was less than that of wild-type (WT) mice. We investigated the contribution of TRPV3 to wound healing using a molar tooth extraction model and found that oral wound closure was delayed in TRPV3KO mice compared with that in WT mice. TRPV3 mRNA was up-regulated in wounded tissues, suggesting that TRPV3 may contribute to oral wound repair. We identified TRPV3 as an essential receptor in heat-induced oral epithelia proliferation and wound healing. Our findings suggest that TRPV3 activation could be a potential therapeutic target for wound healing in skin and oral mucosa.
Assuntos
Mucosa Bucal/lesões , Canais de Cátion TRPV/fisiologia , Cicatrização/fisiologia , Animais , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Receptores ErbB/metabolismo , Temperatura Alta , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucosa Bucal/patologia , Mucosa Bucal/fisiopatologia , Fosforilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Canais de Cátion TRPV/deficiência , Canais de Cátion TRPV/genética , Extração Dentária , Cicatrização/genéticaRESUMO
Transient Receptor Potential Vanilloid (TRPV) 4 is one of the temperature-sensitive ion channels involved in temperature receptors, and it is known to be activated from 35 to 40ºC. Here we analyzed sperm motility function of Trpv4 knockout (KO) mouse in temperature-gradient conditions to elucidate the thermotaxis of mouse sperm and the involvement of TRPV4 in thermotaxis. The sperm were introduced at the vertical column end of a T-shaped chamber filled with medium in a plastic dish, and we measured the number of sperm that arrived at both ends of the wide column where we had established a temperature gradient of approx. 2ºC, and we evaluated the sperm's thermotaxis. Large numbers of wild-type (WT) mouse sperm migrated into the high level of the temperature gradient that was set in the wide column, and thermotaxis was confirmed. The ratio of migrated sperm at the high temperature level of the T-shaped chamber was decreased in the KO sperm and Ruthenium red (a TRPV antagonist) treated sperm compared with the WT sperm. The thermotaxis of the mouse sperm was confirmed, and the involvement of TRPV4 in this thermotaxis was suggested.
Assuntos
Motilidade dos Espermatozoides/fisiologia , Espermatozoides/metabolismo , Canais de Cátion TRPV/metabolismo , Resposta Táctica/fisiologia , Animais , Masculino , Camundongos , Camundongos Knockout , Canais de Cátion TRPV/genéticaRESUMO
Transient receptor potential vanilloid 4 (TRPV4) channel is a physiological sensor for hypo-osmolarity, mechanical deformation, and warm temperature. The channel activation leads to various cellular effects involving Ca(2+) dynamics. We found that TRPV4 interacts with beta-catenin, a crucial component linking adherens junctions and the actin cytoskeleton, thereby enhancing cell-cell junction development and formation of the tight barrier between skin keratinocytes. TRPV4-deficient mice displayed impairment of the intercellular junction-dependent barrier function in the skin. In TRPV4-deficient keratinocytes, extracellular Ca(2+)-induced actin rearrangement and stratification were delayed following significant reduction in cytosolic Ca(2+) increase and small GTPase Rho activation. TRPV4 protein located where the cell-cell junctions are formed, and the channel deficiency caused abnormal cell-cell junction structures, resulting in higher intercellular permeability in vitro. Our results suggest a novel role for TRPV4 in the development and maturation of cell-cell junctions in epithelia of the skin.
Assuntos
Junções Intercelulares/metabolismo , Queratinócitos/metabolismo , Canais de Cátion TRPV/metabolismo , Actinas/química , Actinas/metabolismo , Animais , Células COS , Cálcio/química , Cálcio/metabolismo , Comunicação Celular , Chlorocebus aethiops , Citoesqueleto/metabolismo , Feminino , Queratinócitos/citologia , Masculino , Camundongos , Modelos Biológicos , Concentração Osmolar , Temperatura , beta Catenina/metabolismoRESUMO
Transient receptor potential V3 (TRPV3) and TRPV4 are heat-activated cation channels expressed in keratinocytes. It has been proposed that heat-activation of TRPV3 and/or TRPV4 in the skin may release diffusible molecules which would then activate termini of neighboring dorsal root ganglion (DRG) neurons. Here we show that adenosine triphosphate (ATP) is such a candidate molecule released from keratinocytes upon heating in the co-culture systems. Using TRPV1-deficient DRG neurons, we found that increase in cytosolic Ca(2+)-concentration in DRG neurons upon heating was observed only when neurons were co-cultured with keratinocytes, and this increase was blocked by P2 purinoreceptor antagonists, PPADS and suramin. In a co-culture of keratinocytes with HEK293 cells (transfected with P2X(2) cDNA to serve as a bio-sensor), we observed that heat-activated keratinocytes secretes ATP, and that ATP release is compromised in keratinocytes from TRPV3-deficient mice. This study provides evidence that ATP is a messenger molecule for mainly TRPV3-mediated thermotransduction in skin.
Assuntos
Trifosfato de Adenosina/fisiologia , Queratinócitos/fisiologia , Células Receptoras Sensoriais/metabolismo , Canais de Cátion TRPV/fisiologia , Animais , Cálcio/metabolismo , Células Cultivadas , Técnicas de Cocultura , Gânglios Espinais/citologia , Ácido Glutâmico/metabolismo , Temperatura Alta , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Técnicas de Patch-Clamp , Serotonina/metabolismo , Transdução de Sinais/fisiologia , Pele/metabolismoRESUMO
Although exposure to inorganic arsenic is a health concern, especially in developing foetuses and children, dietary exposure levels among pregnant women and children have not been extensively studied in Japan. To address this shortcoming, we completed a 3-day duplicate diet study for 104 children and 101 pregnant women in two cities, Shimotsuke, Tochigi and Asahikawa, Hokkaido. The levels of intake of total and inorganic arsenic were estimated using the concentrations of total and inorganic arsenic in food and drinking water measured by inductively coupled plasma-mass spectrometry. Estimated intakes of total and inorganic arsenic were 8.46 ± 3.02 [µg/kg BW/week] and 1.74 ± 1.07 [µg/kg BW/week] in pregnant women and 20.07 ± 3.53 [µg/kg BW/week] and 8.46 ± 3.02 [µg/kg BW/week] in children, respectively. Weekly arsenic exposure per kg body weight was significantly higher in children than in pregnant women. Concentrations of total arsenic were generally very low in collected drinking water samples with a small number of exceptions, and drinking water was not considered as a major source of inorganic arsenic exposure in Japan. We found that total and inorganic arsenic intake were higher among frequent consumers of hijiki seaweed, in both pregnant women and children. Although rice and rice products that are staple foods of the Japanese have been reported to be major sources of inorganic arsenic exposure in Japan, our results indicate that hijiki consumption elevates levels of inorganic arsenic in Japanese children and pregnant women. More efforts are necessary to reduce the risk of exposure to inorganic arsenic in populations highly sensitive to environmental pollutants.
Assuntos
Arsênio/análise , Contaminação de Alimentos/análise , Alga Marinha/química , Adulto , Pré-Escolar , Exposição Dietética , Feminino , Humanos , Lactente , Japão , Masculino , Gravidez , Adulto JovemRESUMO
Physiological body temperature is an important determinant for neural functions, and it is well established that changes in temperature have dynamic influences on hippocampal neural activities. However, the detailed molecular mechanisms have never been clarified. Here, we show that hippocampal neurons express functional transient receptor potential vanilloid 4 (TRPV4), one of the thermosensitive TRP (transient receptor potential) channels, and that TRPV4 is constitutively active at physiological temperature. Activation of TRPV4 at 37 degrees C depolarized the resting membrane potential in hippocampal neurons by allowing cation influx, which was observed in wild-type (WT) neurons, but not in TRPV4-deficient (TRPV4KO) cells, although dendritic morphology, synaptic marker clustering, and synaptic currents were indistinguishable between the two genotypes. Furthermore, current injection studies revealed that TRPV4KO neurons required larger depolarization to evoke firing, equivalent to WT neurons, indicating that TRPV4 is a key regulator for hippocampal neural excitabilities. We conclude that TRPV4 is activated by physiological temperature in hippocampal neurons and thereby controls their excitability.
Assuntos
Temperatura Corporal , Hipocampo/citologia , Potenciais da Membrana/fisiologia , Neurônios/fisiologia , Canais de Cátion TRPV/fisiologia , Animais , Animais Recém-Nascidos , Astrócitos , Cálcio/metabolismo , Células Cultivadas , Córtex Cerebral/citologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Expressão Gênica/fisiologia , Proteínas de Fluorescência Verde/metabolismo , Humanos , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas do Tecido Nervoso/metabolismo , Neurônios/classificação , Neurônios/efeitos dos fármacos , Neurônios/efeitos da radiação , Técnicas de Patch-Clamp/métodos , Ésteres de Forbol/farmacologia , RNA Mensageiro/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Canais de Cátion TRPV/deficiênciaRESUMO
Mechanosensing is one of the crucial components of the biological events. In bone, as observed in unloading-induced osteoporosis in bed ridden patients, mechanical stress determines the levels of bone mass. Many molecules have been suggested to be involved in sensing mechanical stress in bone, while the full pathways for this event has not yet been identified. We examined the role of TRPV4 in unloading-induced bone loss. Hind limb unloading induced osteopenia in wild-type mice. In contrast, TRPV4 deficiency suppressed such unloading-induced bone loss. As underlying mechanism for such effects, TRPV4 deficiency suppressed unloading-induced reduction in the levels of mineral apposition rate and bone formation rate. In these mice, unloading-induced increase in the number of osteoclasts in the primary trabecular bone was suppressed by TRPV4 deficiency. Unloading-induced reduction in the longitudinal length of primary trabecular bone was also suppressed by TRPV4 deficiency. TRPV4 protein is expressed in both osteoblasts and osteoclasts. These results indicated that TRPV4 plays a critical role in unloading-induced bone loss.
Assuntos
Reabsorção Óssea/metabolismo , Elevação dos Membros Posteriores , Canais de Cátion TRPV/metabolismo , Células 3T3 , Animais , Feminino , Fêmur/anatomia & histologia , Fêmur/metabolismo , Fêmur/patologia , Elevação dos Membros Posteriores/efeitos adversos , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Osteoblastos/citologia , Osteoblastos/metabolismo , Osteoclastos/citologia , Osteoclastos/metabolismo , Distribuição Aleatória , Canais de Cátion TRPV/genética , Tomografia Computadorizada por Raios XRESUMO
Transient receptor potential (TRP) channels respond to diverse external stimuli and convert them into intracellular calcium signals. Recent evidence shows that TRPV4, one of the vanilloid subfamily, plays a key role in mechanosensation in bone. Here I summarize the current knowledge on possible functions of TRP channels.
Assuntos
Canais de Cátion TRPC/fisiologia , Animais , Densidade Óssea , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Sinalização do Cálcio/genética , Sinalização do Cálcio/fisiologia , Humanos , Mecanotransdução Celular/genética , Mecanotransdução Celular/fisiologia , Camundongos , Osteogênese/genética , Osteogênese/fisiologia , Estresse MecânicoRESUMO
Lead (Pb) in petrol has been banned in developed countries. Despite the control of Pb in petrol since 2001, high levels were reported in the blood of pregnant women and children in Pakistan. However, the identification of sources of Pb has been elusive due to its pervasiveness. In this study, we assessed the lead intake of pregnant women and one- to three-year-old children from food, water, house dust, respirable dust, and soil. In addition, we completed the fingerprinting of the Pb isotopic ratios (LIR) of petrol and secondary sources (food, house-dust, respirable dust, soil, surma (eye cosmetics)) of exposure within the blood of pregnant women, newborns, and children. Eight families, with high (~50 µg/dL), medium (~20 µg/dL), and low blood levels (~10 µg/dL), were selected from 60 families. The main sources of exposure to lead for children were food and house-dust, and those for pregnant women were soil, respirable dust, and food. LIR was determined by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) with a two sigma uncertainty of ±0.03%. The LIR of mothers and newborns was similar. In contrast, surma, and to a larger extent petrol, exhibited a negligible contribution to both the child's and mother's blood Pb. Household wet-mopping could be effective in reducing Pb exposure. This intake assessment could be replicated for other developing countries to identify sources of lead and the burden of lead exposure in the population.
Assuntos
Exposição Ambiental/análise , Chumbo/análise , Gestantes , Adulto , Pré-Escolar , Culinária , Cosméticos/análise , Poeira/análise , Feminino , Análise de Alimentos , Gasolina/análise , Humanos , Lactente , Recém-Nascido , Chumbo/sangue , Masculino , Paquistão/epidemiologia , Gravidez , Solo/química , Sulfetos , Água/análiseRESUMO
Transient receptor potential vanilloid 4 (TRPV4), a cation channel responsive to hypotonicity, can also be activated by warm temperatures. Moreover, TRPV4-/- mice reportedly exhibit deficits in inflammation-induced thermal hyperalgesia. However, it is unknown whether TRPV4 or related transient receptor potential channels account for warmth perception under injury-free conditions. We therefore investigated the contribution of TRPV4 to thermosensation and thermoregulation in vivo. On a thermal gradient, TRPV4-/- mice selected warmer floor temperatures than wild-type littermates. In addition, whereas wild-type mice failed to discriminate between floor temperatures of 30 and 34 degrees C, TRPV4-/- mice exhibited a strong preference for 34 degrees C. TRPV4-/- mice also exhibited prolonged withdrawal latencies during acute tail heating. TRPV4-/- and wild-type mice exhibited similar changes in behavior on a thermal gradient after paw inflammation. Circadian body temperature fluctuations and thermoregulation in a warm environment were also indistinguishable between genotypes. These results demonstrate that TRPV4 is required for normal thermal responsiveness in vivo.
Assuntos
Proteínas de Transporte de Cátions/fisiologia , Temperatura Alta , Canais Iônicos/fisiologia , Transtornos da Percepção/genética , Animais , Artrite Experimental/fisiopatologia , Artrite Experimental/psicologia , Regulação da Temperatura Corporal , Proteínas de Transporte de Cátions/deficiência , Proteínas de Transporte de Cátions/genética , Ritmo Circadiano , Adjuvante de Freund/toxicidade , Genótipo , Abrigo para Animais , Canais Iônicos/deficiência , Canais Iônicos/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transtornos da Percepção/fisiopatologia , Fenótipo , Tempo de Reação , Canais de Cátion TRPVRESUMO
Transient receptor potential vanilloid 4, the Ca2+-permeable cation channel has been proposed as an osmosensitive and a mechanosensitive channel. We investigated functional expression of transient receptor potential vanilloid 4 in inner hair cells, outer hair cells, and spiral ganglion neurons of the mouse cochlea. Transient receptor potential vanilloid 4 mRNA and protein were expressed in inner hair cells, outer hair cells, and spiral ganglion neurons on the basis of the findings of reverse transcriptase-polymerase chain reaction, single-cell reverse transcriptase-polymerase chain reaction, and immunohistochemistry, whereas they were negative in transient receptor potential vanilloid 4-/- mice cochleae. Hypotonic stimulation and 4-alpha-phorbol 12,13-didecanoate, a transient receptor potential vanilloid 4 synthetic activator, increased the intracellular Ca2+ concentrations in wild-type outer hair cells, whereas in transient receptor potential vanilloid 4-/- mice, outer hair cells failed to exhibit a Ca2+ response to both stimulations. In conclusion, transient receptor potential vanilloid 4 may function as an osmosensory and a mechanosensory receptor in the cochlea.
Assuntos
Cóclea/citologia , Cóclea/metabolismo , Regulação da Expressão Gênica/fisiologia , Neurônios/metabolismo , Canais de Cátion TRPV/fisiologia , Animais , Northern Blotting/métodos , Western Blotting/métodos , Cálcio/metabolismo , Quelantes/farmacologia , Interações Medicamentosas , Ácido Egtázico/farmacologia , Regulação da Expressão Gênica/genética , Soluções Hipotônicas/farmacologia , Imuno-Histoquímica/métodos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/efeitos dos fármacos , Forbóis/farmacologia , RNA Mensageiro/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Rutênio Vermelho/metabolismo , Canais de Cátion TRPV/deficiênciaRESUMO
This study aimed to evaluate the relationships between oxidative stress and heavy metal exposure (lead [Pb] and cadmium [Cd]), as well as co-factors such as physical activity and age, in Japanese women. This study was conducted with female subjects from a rural agricultural community in Japan. Subjects were asked to complete lifestyle-related questionnaires and undergo a group health examination. Physical activity, alcohol consumption, body mass index, and other demographic information were collected. Blood and urine samples were collected to measure urinary 8-hydroxydeoxyguanosine (8-OHdG) levels and blood and urinary Cd and Pb concentrations. Urine samples were analyzed using high performance liquid chromatography and flameless atomic absorption spectrometry; blood samples were analyzed using inductively coupled plasma-mass spectrometry. Age, physical activity, and blood and urinary Cd and Pb concentrations were included in structural equation modeling analysis. Two latent factors for heavy metal exposure and physical activity were produced to predict the total influence of the variables. The final model was good: CMIN/DF = 0.775, CFI = 1.000, GFI = 0.975, AGFI = 0.954, RMSEA = 0.000. 8-OHdG levels were positively associated with heavy metal exposure, physical activity, and age (standard ß of path analysis: 0.33, 0.38, and 0.20, respectively). Therefore, oxidative stress is associated with both, environmental and lifestyle factors, in combination with aging.
RESUMO
Adverse health effects of heavy metals are a public health concern, especially lead may cause negative health impacts to human fetal and infantile development. The lead concentrations in Pakistani pregnant women's nails, used as a biomarker, were measured to estimate the lead exposure. Thirteen nail samples out of 84 nails analyzed contained lead higher than the concentration (13.6 µg/g) of the fatal lead poisoning case, raising the possibility of an external contamination. Eye cosmetics such as surma are recognized as one of the important sources of lead exposure in Pakistan. We collected in Pakistan 30 eye cosmetics made in Pakistan, Saudi Arabia and western countries. As the metal composition analysis by energy dispersive X-ray fluorescence spectrometry revealed that some surma samples contained lead more than 96%, the surma might contaminate the nail specimen. Scanning electron microscopy observations showed that lead-containing surma consists of fine particle of galena (ore of lead sulfide) in respirable dust range (less than 10 µm). In addition, relative in vitro bioavailability of lead in the surma was determined as 5.2%. Thus, lead-containing surma consists of inhalable and bioavailable particles, and it contributes an increased risk of lead exposure. Moreover, the relationship between the surma and the lead-contaminated nails by lead isotope ratios analysis indicated the potential of lead contamination in nails by surma. These results suggest that lead in the nails was derived both from body burden of lead and external contamination by lead-containing surma. Therefore, nail is not suited as a biomarker for lead exposure in the countries where surma used, because we may overestimate lead exposure by surface lead contamination in the nail by surma.
Assuntos
Cosméticos/química , Intoxicação por Chumbo , Chumbo/química , Metais Pesados/química , Unhas/química , Sulfetos/química , Biomarcadores/análise , Poeira/análise , Feminino , Humanos , Chumbo/análise , Microscopia Eletrônica de Varredura , Paquistão , GravidezRESUMO
AIM: Exposure assessment of lead (Pb) and Arsenic (As) from food, water, and house dust intake were assessed among pregnant women, their children and fetuses in Pakistan and Japan, as well as their body burden of the metals in their blood. METHOD: Fifty families which included a pregnant woman, a fetus and the 1-3-year-old siblings were recruited in Karachi and Khairpur in Pakistan, and Shimotsuke and Asahikawa in Japan, respectively. Their dietary exposure to Pb and As was measured in 3-day food duplicates and drinking water by ICP-MP. Pb in house dust and respirable dust was evaluated with an energy dispersive X-ray fluorescence spectrometry. Non-radioactive isotope Pb profiles of blood specimens will be compared with those of the exposure origins, such as food duplicates, respirable house dust, the soils nearby, and gasoline. RESULTS: Judging from the data collected and analyzed so far, contribution from dietary intake is highly correlated to higher body burden of Pb among Pakistani mothers. Additional data analyses will reveal the status of Pb and As body burden in Pakistani mothers, fetuses and their siblings, and causal sources of high body burden is delineated by Pb isotope profile analysis of different sources of Pb exposure.
Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Arsênio/análise , Exposição Ambiental , Contaminação de Alimentos , Chumbo/análise , Poluentes Químicos da Água/análise , Adulto , Poluentes Atmosféricos/sangue , Arsênio/sangue , Carga Corporal (Radioterapia) , Pré-Escolar , Cidades , Poeira/análise , Feminino , Sangue Fetal/química , Feto , Humanos , Lactente , Japão , Chumbo/sangue , Masculino , Mães , Paquistão , Gravidez , Irmãos , Poluentes Químicos da Água/sangue , Adulto JovemRESUMO
Six of the mammalian transient receptor potential (TRP) ion channel subtypes are nonselective cation channels that can be activated by increases or decreases in ambient temperature. Five of them can alternatively be activated by nonthermal stimuli such as capsaicin [transient receptor potential vanilloid 1 (TRPV1)] or hypo-osmolarity (TRPV2 and TRPV4). No nonthermal stimuli have yet been described for TRPV3, a warmth-gated ion channel expressed prominently in skin keratinocytes. Here, we demonstrate that 2-aminoethoxydiphenyl borate (2-APB), a compound used to inhibit store-operated Ca2+ channels and IP3 receptors, produces robust activation of recombinant TRPV3 in human embryonic kidney 293 cells with an EC50 of 28 microm. 2-APB also sensitizes TRPV3 to activation by heat, even at subthreshold concentrations. In inside-out membrane patches from TRPV3-expressing cells, 2-APB increases the open probability of TRPV3. Also, whereas heat alone is capable of activating TRPV3-mediated currents in only a small proportion of primary mouse keratinocytes, 2-APB activates heat-evoked, TRPV3-mediated currents in the majority of these cells. Together, these findings identify 2-APB as the first known chemical activator of TRPV3 and enhance the notion that TRPV3 participates in the detection of heat by keratinocytes.
Assuntos
Compostos de Boro/farmacologia , Proteínas de Transporte de Cátions/efeitos dos fármacos , Temperatura Alta , Ativação do Canal Iônico/efeitos dos fármacos , Canais Iônicos/efeitos dos fármacos , Queratinócitos/efeitos dos fármacos , Animais , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Ativação do Canal Iônico/fisiologia , Canais Iônicos/genética , Canais Iônicos/metabolismo , Queratinócitos/citologia , Queratinócitos/metabolismo , Rim/citologia , Rim/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Técnicas de Patch-Clamp , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Canais de Cátion TRPV , Sensação Térmica/fisiologia , TransfecçãoRESUMO
BACKGROUND: It is recognized that colonization by Staphylococcus aureus (SA) on the skin is one of the factors that can worsen atopic dermatitis (AD). Antibiotics and germicides are not the best choice to remove bacteria from the skin of AD patients, because of problems of irritation to the skin and bacterial resistance. We therefore turned our attention to the biofilm of SA with the aim of removing only SA from the skin surface of AD patients. We found that xylitol (X) and farnesol (F) synergistically inhibited biofilm formation by SA and dissolved biofilm formed in vivo (Part 1). OBJECTIVE: To test whether application of AD for 1 week with FX cream can reduce SA without affecting Staphylococcus epidermidis. METHODS: A randomized, double-blind, placebo-controlled right-and-left comparison study was performed. The arms of 17 patients with dry-type AD were applied with skin-care cream including/or not including a 0.02% F and 5% X combination for 1 week. The clinical response, biophysical assessment of the skin surface and counts of skin microflora were recorded before and after 1 week of therapy. RESULTS: The ratio of SA in total bacteria at sites to which FX cream had been applied was significantly decreased after 1 week (P = 0.007), compared with before application and with placebo sites (P = 0.045). The mean skin conductance (a parameter indicating the state of hydration of the skin surface) of FX cream sites was increased significantly compared with the conductance before application (P = 0.0001) and at placebo sites (P = 0.002). CONCLUSION: This study provides evidence supporting the idea that cream containing F and X is a useful skin-care agent for atopic dry skin colonized by SA.
Assuntos
Dermatite Atópica/tratamento farmacológico , Dermatite Atópica/microbiologia , Farneseno Álcool/administração & dosagem , Pele/efeitos dos fármacos , Pele/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Xilitol/administração & dosagem , Administração Cutânea , Adulto , Água Corporal/metabolismo , Contagem de Colônia Microbiana , Dermatite Atópica/metabolismo , Dermatite Atópica/patologia , Fármacos Dermatológicos/administração & dosagem , Método Duplo-Cego , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pele/patologia , Staphylococcus aureus/ultraestrutura , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/fisiologiaRESUMO
Transient receptor potential channel vanilloid subfamily 4 (TRPV4), a member of TRP family, is a mechanosensitive non-selective cation channel. To investigate the role of TRPV4 in the cochlea, the hearing thresholds and effects of acoustic overexposure on the cochlea were examined in TRPV4 knockout mice. TRPV4 knockout mice at age 8 weeks exhibited normal, but those at 24 weeks revealed significantly higher thresholds by auditory brainstem response. The auditory threshold shift was significantly larger in the TRPV4 knockout than in the TRPV4+/+ mice 1 week after the acoustic overexposure of 128dB SPL. The present findings suggest that disruption of TRPV4 causes delayed-onset hearing loss and makes the cochlea vulnerable to acoustic injury.
Assuntos
Córtex Auditivo/fisiopatologia , Proteínas de Transporte de Cátions/genética , Cóclea/patologia , Transtornos da Audição/genética , Canais Iônicos/genética , Estimulação Acústica , Animais , Limiar Auditivo/fisiologia , Feminino , Masculino , Camundongos , Camundongos Knockout , Canais de Cátion TRPVRESUMO
Members of the transient receptor potential (TRP) family of ion channels play important roles in inflammation and pain. Here, we showed that both TRPV1 and TRPV4 might contribute to biphasic nocifensive behavior and neuroendocrine response following a formalin test. We subcutaneously injected saline, formalin, or the TRPV4 agonist, 4α-phorbol 12,13-didecanoate (4α-PDD) into one hindpaw of wild-type (WT), TRPV1-deficient (Trpv1(-/-)), and TRPV4-deficient (Trpv4(-/-)) mice to investigate nocifensive behaviors (phase I [0-10 min] and phase II [10-60 min]) and Fos expression in the dorsal horn of the spinal cord and other brain regions related to pain, in the paraventricular nucleus (PVN), paraventricular nucleus of the thalamus, the medial habenular nucleus, the medial nucleus of the amygdala and capsular part of the central amygdala. Subcutaneous (s.c.) injection of formalin caused less nocifensive behavior in Trpv1(-/-) and Trpv4(-/-) mice than in WT mice during phase I. In phase II, however, formalin induced less nocifensive behavior only in the Trpv1(-/-) mice, but not in the Trpv4(-/-) mice, relative to WT mice. The number of Fos-like immunoreactive (LI) neurons in laminae I-II of the dorsal horn increased in all types of mice 90 min after s.c. injection of formalin; however, there was no difference in the other regions between saline- and formalin-treated mice. Furthermore, s.c. injection of 4α-PDD did not induce nociceptive behavior nor influence the number of Fos-LI neurons in the all above mentioned regions in any of the mice. These results suggest that TRPV4-mediated nociceptive information from the peripheral tissue excluding the spinal pathway might be involved the formalin behavioral response during phase I. Only TRPV1 might regulate the formalin behavioral response in peripheral neuron.
Assuntos
Nociceptores/metabolismo , Dor/metabolismo , Canais de Cátion TRPV/metabolismo , Animais , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Sistemas Neurossecretores/metabolismo , Medição da Dor/métodos , Ésteres de Forbol , Proteínas Proto-Oncogênicas c-fos/metabolismo , Medula Espinal/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Canais de Cátion TRPV/agonistas , Canais de Cátion TRPV/deficiênciaRESUMO
A transient receptor potential (TRP) family, TRPV4, is a calcium-permeable swell-activated channel, playing a role in cutaneous mechanosensation. To elucidate the localization in the mechanosensitive endings, we found with immunohistochemistry in mice that TRPV4 was expressed both by small (low threshold) and large (high threshold) dorsal root ganglia neurons. In addition to free nerve endings, TRPV4 was specifically located at cutaneous mechanosensory terminals co-localized with neurofilament 200, including Meissner, Merkel, penicillate and intraepidermal terminals but not including hair follicle palisades. The distribution suggests that the sensation of pressure by mechanosensitive TRPV4 channel is transmitted through A- as well as C-fiber.