Infantile Pain Episodes Associated with Novel Nav1.9 Mutations in Familial Episodic Pain Syndrome in Japanese Families

Painful peripheral neuropathy has been correlated with various voltage-gated sodium channel mutations in sensory neurons. Recently Nav1.9, a voltage-gated sodium channel subtype, has been established as a genetic influence for certain peripheral pain syndromes. In this study, we performed a genetic study in six unrelated multigenerational Japanese families with episodic pain syndrome. Affected participants (n = 23) were characterized by infantile recurrent pain episodes with spontaneous mitigation around adolescence. This unique phenotype was inherited in an autosomal-dominant mode. Linkage analysis was performed for two families with 12 affected and nine unaffected members, and a single locus was identified on 3p22 (LOD score 4.32). Exome analysis (n = 14) was performed for affected and unaffected members in these two families and an additional family. Two missense variants were identified: R222H and R222S in SCN11A. Next, we generated a knock-in mouse model harboring one of the mutations (R222S). Behavioral tests (Hargreaves test and cold plate test) using R222S and wild-type C57BL/6 (WT) mice, young (8-9 weeks old; n = 10-12 for each group) and mature (36-38 weeks old; n = 5-6 for each group), showed that R222S mice were significantly (p < 0.05) more hypersensitive to hot and cold stimuli than WT mice. Electrophysiological studies using dorsal root ganglion neurons from 8-9-week-old mice showed no significant difference in resting membrane potential, but input impedance and firing frequency of evoked action potentials were significantly increased in R222S mice compared with WT mice. However, there was no significant difference among Nav1.9 (WT, R222S, and R222H)-overexpressing ND7/23 cell lines. These results suggest that our novel mutation is a gain-of-function mutation that causes infantile familial episodic pain. The mouse model developed here will be useful for drug screening for familial episodic pain syndrome associated with SCN11A mutations

ガン カガク リョウホウ ニオケル ショウカカン ドクセイ ト ケッセイ Diamine Oxidase DAO カッセイ ニ カンスル ケントウ

There are so many patients with advanced gastric cancer who undergo systemic chemotherapy worldwide. The quality of life（QOL）of patients with gastric cancer who receive chemotherapy is often lowed by various gastrointestinal toxicities during the chemotherapy. Nutrition is also impaired by gastrointestinal toxicities. However, it is difficult to predict their occurrence in advance and further there is no good serum marker for nutrition in the patients treated with chemotherapy. Thus, it is important to objectively evaluate and predict the toxicity of the digestive tract during cancer chemotherapy. Diamine Oxidase（DAO）is an enzyme that is expressed in intestinal epithelial cells. Recently it has been reported that DAO activity may reflect damage or atrophy of the intestinal villi, and therefore it may be a sensitive serum marker for nutritional state. In this study, we measured serum DAO activity of patients with gastric cancer treated with systemic chemotherapy, and investigated the correlation between DAO activity and gastrointestinal toxicities. Six patients with gastric cancer, who were treated by docetaxel+cisplatin+S‐１combination chemotherapy, were enrolled. DAO activity was measured by sensitive colorimetric assay. DAO activities diminished after treatment in４patients with moderate to severe gastrointestinal toxicities. In contrast, they did not change in２patients with no gastrointestinal toxicities. Our results may suggest that DAO activity is a good serum marker for the gastrointestinal toxicities as well as nutrition state in patients who receive systemic chemotherapy. More large scale study is needed to warrant

Distribution of the Steller sea lion Eumetopias jubatus during winter in the northern Sea of Japan, along the west coast of Hokkaido, based on aerial and land sighting surveys

Aerial and land-based sighting surveys were conducted to clarify the distribution of Steller sea lions during winter in the northern Sea of Japan, along the west coast of Hokkaido, from 2001 to 2003. Aerial surveys revealed that sea lions gathered around the Rishiri-Rebun Islands in March 2002 and 2003, and between Iwanai and Cape Obana in February 2003. Higher numbers of sea lions were also confirmed at Cape Ofuyu and Cape Kamui on the central-west coast compared to that at the haul-out sites in the 1980s on the upper-west coast in March 2002 and 2003. Additionally, fisherman observed sea lions along the coast of the Tsugaru Strait from February to May 2003, where the presence of sea lions was not reported in the 1980s. These facts suggest that sea lions have recently expanded their distribution southward. Land-based surveys at the recent haul-out sites indicated that sea lions in the central-west coast were composed mainly of adult and subadult males (average: Cape Ofuyu 75.2%, Cape Kamui 69.5%), which stayed from November 2002 to May 2003. In this area, sea lions arrived earlier and stayed longer than in the 1980s

Functional linkage between TRPV4 and calcium-activated chloride channels in choroid plexus epithelial cells

Transient receptor potential vanilloid 4 (TRPV4) is a non-selective cation channel known to be a sensorfor hypo-osmolality, cell swelling, warm temperatures and some chemical compounds. Furthermore,the physiological significance of TRPV4 has attracted a great deal of attention, particularly itsheat-sensitive properties. Previous reports showed the physiological functions of TRPV4 in severalcell types, including skin, esophageal keratinocytes and hippocampal neurons. For instance, TRPV4expressed in skin keratinocytes contributes to the enhancement of the skin barrier function at bodytemperature. Moreover, the release of ATP from esophageal keratinocytes or bladder epithelium isenhanced by extension-mediated TRPV4 activation. Additionally, neural activity increases with a risein temperature in hippocampal neurons. However, the precise function of TRPV4 in the brain is stillunknown except for regulation of neural activity in the hippocampus. In this study, the highestexpression of TRPV4 in choroid plexus epithelial cells (CPECs) was found using in situ hybridization,immunohistochemistry and EGFP expression in transgenic mice in which EGFP was expressed inTRPV4-positive cells. In addition, calcium-activated chloride currents were observed for the first timein CPECs. Moreover, expression of anoctamin 1 (Ano1), Ano4, Ano6 and Ano10 genes in the choroidplexus was found by RT-PCR. These data suggest that upon TRPV4 activation, calcium enteringCPECs enhances production of cerebrospinal fluid (CSF), a process dependent upon ion transports.To investigate this hypothesis, whole-cell patch-clamp recordings in HEK293T cells were performed.ANO1-mediated chloride currents were dramatically increased in HEK293T cells expressing mouseTRPV4 and mouse ANO1 when TRPV4 was activated by a low concentration of GSK1016790A(GSK). In contrast, the GSK-induced chloride currents were not significantly affected in the cellsexpressing ANO4, ANO6 or ANO10 with TRPV4. Additionally, the GSK-induced chloride currentsin the cells expressing ANO1 and TRPV4 were not observed in the absence of extracellular calcium.These results indicated that chloride efflux through ANO1 depended on TRPV4 activity. SimilarGSK-induced chloride currents were observed in CPECs isolated from the lateral and the fourthventricle choroid plexus. Interestingly, the GSK-induced chloride currents were strongly inhibited byan ANO1/ANO2 blocker, T16Ainh-A01 (A01), and ANO2 expression was not suggested in choroidplexus. These results indicated a functional linkage between TRPV4 and ANO1 in CPECs. This isthe first reported case of the linkage of these two proteins in native cells. It was recently reported thatANO1 is activated by noxious heat. In the author’s study, ANO1 was activated by heat in the range ofbody temperature. Heat-evoked chloride currents were also observed in CPECs isolated fromwild-type (WT) and TRPV4-deficient (TRPV4KO) mice. Furthermore, heat-evoked currents weredrastically enhanced after GSK application in WT, but not in TRPV4KO CPECs. These resultsindicated the possibility that heat-sensitivity of ANO1 is enhanced by TRPV4 activation in CPECs.However, the enhanced currents were not completely blocked by A01. Thus, the possibility of anotherheat-activated chloride channels also was suggested in CPECs.Accordingly, the author proposes a concept that functional linkage between TRPV4 and ANO1enhances CSF production. First, the apical membrane of CPECs is extended by water influx from thebasolateral side. Second, phospholipase A2 (PLA2) activity is increased by the extension of the plasmamembrane and arachidonic acid is produced from phospholipids by the activated PLA2. Then,arachidonic acid is metabolized to epoxyeicosatrienoic acid (EET) by cytochrome P450 epoxygenaseactivity, and TRPV4 is activated by EET at body temperature. The TRPV4 activation leads to calciuminflux, which in turn leads to ANO1 activation at body temperature. Finally, water efflux from CPECsis driven by efflux of chloride and some cations through a Donnan equilibrium. Production, transportand reabsorption of CSF are important for the maintenance of the brain environment in fetuses andadults. Among the three CSF-related events, the principle role of CPECs is CSF production. CSFtransport is controlled by ependymal cells and the reabsorption is done by arachnoid granulation to thedural venous sinuses. Dysfunction of ciliary motility and the failure of cilia development ofependymal cells induce severe hydrocephalus. This indicates that CSF is continuously secreted fromCPECs and the production is independent of the changes in brain pressure. There are currently onlypalliative therapies for hydrocephalus including external ventricular drainage or placement of a surgicalshunt. Control of CSF production through regulation of TRPV4 activity could allow a safer way totreat those diseases. Thus, these studies suggest a fundamental new therapy for hydrocephalus causedby choroid plexus cysts and choroid plexus papillomas