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1.
PLoS One ; 19(6): e0304703, 2024.
Article in English | MEDLINE | ID: mdl-38900750

ABSTRACT

Arginine vasopressin (AVP) and oxytocin (OT) are well-known as neuropeptides that regulate various social behaviors in mammals. However, little is known about their role in mouse female sexual behavior. Thus, we investigated the role of AVP (v1a and v1b) and OT receptors on female sexual behavior. First, we devised a new apparatus, the bilevel chamber, to accurately observe female mouse sexual behavior. This apparatus allowed for a more precisely measurement of lordosis as receptivity and rejection-like behavior (newly defined in this study), a reversed expression of proceptivity. To address our research question, we evaluated female sexual behavior in mice lacking v1a (aKO), v1b (bKO), both v1a and v1b (dKO), and OT (OTRKO) receptors. aKO females showed decreased rejection-like behavior but a normal level of lordosis, whereas bKO females showed almost no lordosis and no change in rejection-like behavior. In addition, dKO females showed normal lordosis levels, suggesting that the v1b receptor promotes lordosis, but not necessarily, while the v1a receptor latently suppresses it. In contrast, although OTRKO did not influence lordosis, it significantly increased rejection-like behavior. In summary, the present results demonstrated that the v1a receptor inhibits proceptivity and receptivity, whereas the v1b and OT receptors facilitate receptivity and proceptivity, respectively.


Subject(s)
Mice, Knockout , Receptors, Oxytocin , Receptors, Vasopressin , Sexual Behavior, Animal , Animals , Female , Receptors, Vasopressin/metabolism , Receptors, Vasopressin/genetics , Receptors, Oxytocin/metabolism , Receptors, Oxytocin/genetics , Sexual Behavior, Animal/physiology , Mice , Male , Oxytocin/metabolism , Mice, Inbred C57BL , Arginine Vasopressin/metabolism
2.
Biochem Pharmacol ; 225: 116322, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38815630

ABSTRACT

Xenobiotic metabolic reactions in the hepatocyte endoplasmic reticulum (ER) including UDP-glucuronosyltransferase and carboxylesterase play central roles in the detoxification of medical agents with small- and medium-sized molecules. Although the catalytic sites of these enzymes exist inside of ER, the molecular mechanism for membrane permeation in the ER remains enigmatic. Here, we investigated that organic anion transporter 2 (OAT2) regulates the detoxification reactions of xenobiotic agents including anti-cancer capecitabine and antiviral zidovudine, via the permeation process across the ER membrane in the liver. Pharmacokinetic studies in patients with colorectal cancer revealed that the half-lives of capecitabine in rs2270860 (1324C > T) variants was 1.4 times higher than that in the C/C variants. Moreover, the hydrolysis of capecitabine to 5'-deoxy-5-fluorocytidine in primary cultured human hepatocytes was reduced by OAT2 inhibitor ketoprofen, whereas capecitabine hydrolysis directly assessed in human liver microsomes were not affected. The immunostaining of OAT2 was merged with ER marker calnexin in human liver periportal zone. These results suggested that OAT2 is involved in distribution of capecitabine into ER. Furthermore, we clarified that OAT2 plays an essential role in drug-drug interactions between zidovudine and valproic acid, leading to the alteration in zidovudine exposure to the body. Our findings contribute to mechanistically understanding medical agent detoxification, shedding light on the ER membrane permeation process as xenobiotic metabolic machinery to improve chemical changes in hydrophilic compounds.


Subject(s)
Endoplasmic Reticulum , Humans , Endoplasmic Reticulum/metabolism , Drug Interactions/physiology , Hepatocytes/metabolism , Hepatocytes/drug effects , Male , Organic Anion Transporters, Sodium-Independent/metabolism , Organic Anion Transporters, Sodium-Independent/genetics , Zidovudine/metabolism , Zidovudine/pharmacokinetics , Female , Microsomes, Liver/metabolism
3.
In Vitro Cell Dev Biol Anim ; 60(5): 563-568, 2024 May.
Article in English | MEDLINE | ID: mdl-38472720

ABSTRACT

Human pluripotent stem cells, such as human embryonic stem cells and human induced pluripotent stem cells, are used in basic research and various applied fields, including drug discovery and regenerative medicine. Stem cell technologies have developed rapidly in recent years, and the supply of culture materials has improved. This has facilitated the culture of human pluripotent stem cells and has enabled an increasing number of researchers and bioengineers to access this technology. At the same time, it is a challenge to share the basic concepts and techniques of this technology among researchers and technicians to ensure the reproducibility of research results. Human pluripotent stem cells differ from conventional somatic cells in many aspects, and many points need to be considered in their handling, even for those experienced in cell culture. Therefore, we have prepared this proposal, "Points of Consideration for Pluripotent Stem Cell Culture," to promote the effective use of human pluripotent stem cells. This proposal includes seven items to be considered and practices to be confirmed before using human pluripotent stem cells. These are laws/guidelines and consent/material transfer agreements, diversity of pluripotent stem cells, culture materials, thawing procedure, media exchange and cell passaging, freezing procedure, and culture management. We aim for the concept of these points of consideration to be shared by researchers and technicians involved in the cell culture of pluripotent stem cells. In this way, we hope the reliability of research using pluripotent stem cells can be improved, and cell culture technology will advance.


Subject(s)
Cell Culture Techniques , Pluripotent Stem Cells , Humans , Cell Culture Techniques/methods , Pluripotent Stem Cells/cytology , Cryopreservation/methods , Culture Media/chemistry
5.
Article in English | MEDLINE | ID: mdl-37521254

ABSTRACT

Objectives: Although radiotherapy is an essential component of pediatric cancer treatment, inadequate radiotherapy information for childhood cancer and unusual treatment situations can negatively affect parental perceptions and emotions. This study aims to investigate the effect of two-step audio-visual instruction system effects introduced by our institution on parent satisfaction and anxiety when initiating radiotherapy. Methods: The two-step audio-visual instruction system comprised instructive animation using patient avatars and a live video system. The live video system has a 55-inch-wide monitor, and a no-latency sound module. Parents in the radiotherapy division can view the patient in the treatment room through the live video system. This prospective study compared satisfaction and anxiety about radiotherapy introduction before and after two-step audio-visual instruction. We enrolled 20 parents whose child underwent radiotherapy, and they completed a set of questionnaires-Client Satisfaction Questionnaire, State-Trait Anxiety Inventory, and original questionnaires about radiotherapy. Results: Satisfaction scores improved significantly after two-step audio visual instruction (25.5 ± 3.4) compared with those before the instruction (27.7 ± 3.1) (p = <0.01). Anxiety scores also decreased significantly after the instruction (50 ± 9) compared with those before the instruction (54 ± 11) (p = 0.004). However, anxiety-related personality trait scores did not change drastically before and after viewing (48 ± 8.5 vs. 49 ± 7.5) (p = 0.419). Conclusion: This single-arm prospective study indicates that two-step audio-visual instruction for radiotherapy is effective in improving parents' anxiety about radiotherapy introductions. However, large-scale and comparative studies are warranted to generalize the benefit of two-step audio visual instruction.

6.
Eur J Med Genet ; 66(8): 104806, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37379880

ABSTRACT

Kabuki syndrome (KS) is a congenital disorder caused by mutations in either KMT2D on chromosome 12 or KDM6A on chromosome X, encoding a lysine methyltransferase and a lysine demethylase, respectively. A 9-year-4-month-old male patient with a normal karyotype presented with KS and autism spectrum disorder. Genetic testing for KS was conducted by Sanger sequencing and episignature analysis using DNA methylation array data. The patient had a mosaic stop-gain variant in KDM6A and a heterozygous missense variant (rs201078160) in KMT2D. The KDM6A variant is expected to be deleterious. The KMT2D variant pathogenicity has been inconsistently reported in the ClinVar database. Using biobanking resources, we identified two heterozygous individuals possessing the rs201078160 variant. In a subsequent episignature analysis, the KS patient showed the KS episignature, but two control individuals with the rs201078160 variant did not. Our results indicate that the mosaic stop-gained variant in KDM6A, but not the rs201078160 variant in KMT2D, is responsible for the KS phenotype in the patient. This study further demonstrated the utility of DNA methylation information in diagnosing rare genetic diseases and emphasized the importance of a reference dataset containing both genotype and DNA methylation information.


Subject(s)
Autism Spectrum Disorder , Hematologic Diseases , Vestibular Diseases , Humans , Male , Biological Specimen Banks , Codon, Nonsense , Germ Cells , Hematologic Diseases/genetics , Hematologic Diseases/diagnosis , Histone Demethylases/genetics , Lysine/genetics , Mutation , Vestibular Diseases/genetics , Vestibular Diseases/diagnosis
7.
Sci Rep ; 12(1): 21173, 2022 12 07.
Article in English | MEDLINE | ID: mdl-36476676

ABSTRACT

HepG2 cells are widely used as a human hepatocytes model, but their functions, including drug metabolism, are inferior to primary hepatocytes. We previously reported that the hepatic gene expressions in HepG2 cells were upregulated by treatment with zebularine, which is an inhibitor of DNA methylation, through the inhibition of both DNA methyltransferase 1 (DNMT1) and double-stranded RNA-dependent protein kinase (PKR). In this study, we established a new HepG2 cell subline, HepG2-DP cells, by stable double knockdown of DNMT1 and PKR and evaluated its function. Albumin production, expression of CYP1A2 genes, and accumulation of lipid droplets were increased in HepG2-DP cells compared with the original HepG2 cells. Comprehensive gene expression analysis of transcription factors revealed that the expression of important genes for hepatic function, such as HNF1ß, HNF4α, ONECUT1, FOXA1, FOXA2, FOXA3, and various nuclear receptors, was upregulated in HepG2-DP cells. These results indicate that the newly established HepG2-DP cells are a highly functional hepatocyte cell line. In addition, we investigated whether HepG2-DP cells are able to mature by differentiation induction, since HepG2 cells are derived from hepatoblastoma. The gene expression of major CYPs and Phase II, III drug-metabolizing enzyme genes was significantly increased in HepG2-DP cells cultured in differentiation induction medium. These results suggest that HepG2-DP cells can be further matured by the induction of differentiation and could therefore be applied to studies of drug metabolism and pharmacokinetics.


Subject(s)
Cell Differentiation , Humans , Cell Differentiation/genetics
8.
Article in English | MEDLINE | ID: mdl-36497512

ABSTRACT

While wilderness programs are recognized as a feasible intervention to promote psychological independence in adolescence, little is known about physiological changes. The present study focused on oxytocin, a key hormone for social cognition and behavior, and investigated changes in OT concentrations during a wilderness program among adolescents. Twenty-one 4th-7th graders were separated from parents and immersed with adventures and challenges in the woodlands of Motegi, Tochigi Prefecture, Japan for 31 days, and dataset of 20 boys aged 9-13 years-old were used for analysis. OT concentrations in early morning saliva samples on days 2, 5, 8, 13, 18, 20, 21, 22 and 30 were determined using ELIZA. We performed multi-level regression analyses to compare the OT concentrations before and after solo and team-based survival challenges, and across the nine observational points, adjusting for potential covariates. We found that adolescents increased OT level in a situation where they needed others' cooperation and support for survival (coefficient: 2.86, SE: 1.34, p = 0.033). Further, we found that adolescents gradually decreased their basal OT level during a long separation from parents (coefficient: -0.083, SE: 0.034, p = 0.016). A combination of these findings suggest the OT level may be a marker for psychological independence.


Subject(s)
Oxytocin , Saliva , Adolescent , Male , Humans , Child , Japan
9.
Neurosci Res ; 182: 60-64, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35688291

ABSTRACT

We previously reported that mice pups showed individual differences in mother preferences at 16 days old; some pups show high preference to their mother, and other pups show low preference to it. In this study, we examined whether these individual differences were associated with anxiety-like behavior and cognition functions in adulthood. We found that pups showing low mother preference exhibit low anxiety-like behavior and impaired object cognition in adulthood. These results suggest that some behavioral characteristics in adulthood may be associated with the profile of mother preference prior to weaning.


Subject(s)
Behavior, Animal , Mothers , Animals , Anxiety , Female , Humans , Mice , Mice, Inbred C57BL , Weaning
10.
Pediatr Int ; 64(1): e15064, 2022 01.
Article in English | MEDLINE | ID: mdl-35507318

Subject(s)
Robotics , Humans
11.
Biol Cell ; 114(9): 225-236, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35603978

ABSTRACT

BACKGROUND INFORMATION: An in vitro evaluation system using cultured hepatocytes is the most useful method in preclinical research, such as drug metabolism and toxicity test. Human hepatocytes should be used in an in vitro evaluation system because the expression of drug-metabolizing enzymes varies among animal species. HepG2 cells, a liver cancer-derived cell line, are widely used as a human hepatocyte model; however, their hepatic functions are generally weak. RESULTS: In this study, we showed that low-density HepG2 cell culture induces hepatic function. The morphology of HepG2 cells was altered depending on the cell density at the time of seeding. Low-density cultured HepG2 cells proliferated as tightly packed colonies. The HepG2 cell colonies in low-density culture demonstrated enhanced tight junction formation. Tight junction protein gene expression levels, such as those of zonula occludens-1 (ZO-1), junctional adhesion molecule 1 (JAM), claudin, occludin, and tricellulin, increased in low-density cultured HepG2 cells. Phases I and II metabolic enzymes, phase III transporter gene expression, and CYP3A4 activity also increased in low-density cultured HepG2 cells. Occludin and tricellulin knockdown inhibited the increased hepatic function in low-density cultures. Tricellulin knockdown reduced the expression of hepatocyte nuclear factor 6 (HNF6), CCAAT/enhancer-binding protein alpha (CEBPA), and aryl hydrocarbon receptor (AHR). In addition, the expression of nuclear receptor subfamily 1 group h member 2 (NR1H2) increased in low-density cultures, canceled by occludin and tricellulin knockdown. CONCLUSIONS: Our results suggest that low-density HepG2 cell cultures enhance hepatic function by promoting tight junction formation and demonstrate the importance of cell density in drug evaluation using hepatocyte cell lines.


Subject(s)
MARVEL Domain Containing 2 Protein , Tight Junctions , Animals , Cell Culture Techniques , Hep G2 Cells , Humans , MARVEL Domain Containing 2 Protein/metabolism , Occludin/genetics , Occludin/metabolism , Tight Junctions/metabolism
12.
Neurosci Res ; 178: 69-77, 2022 May.
Article in English | MEDLINE | ID: mdl-35114216

ABSTRACT

Mutual attachment between mother and pup is important to enable the mother to care for her pup and for the pup to receive care from its mother. Pups eventually leave their mothers, which is also very important to their growth. The mechanism of preference by which pups transfer attachment from their mother to others remains unknown. In this study, we assessed mother/novel dam preferences and examined the brain regions associated with the regulation of this preference in C57BL/6 mice pups. We found that C57BL/6 mice pups had variety in their mother/novel dam preferences at 16 days old. This variety was not related to the sex of the pups, their weight, or the litter size. In order to clarify the brain mechanisms responsible for this variety, we examined the relationship between mother/novel dam preference and neuronal activation induced by contact with the mother. We found that pups exhibiting novel dam preference had higher neural activity in the anterior cingulate cortex (ACC) and bed nucleus of the stria terminalis (BNST) when exposed to their mother. These results suggest that ACC and/or BNST neural activity may be associated with mother/novel dam preferences in infant mice.


Subject(s)
Maternal Behavior , Mothers , Animals , Brain , Female , Humans , Maternal Behavior/physiology , Mice , Mice, Inbred C57BL , Neurons
13.
Eur J Pediatr ; 181(3): 1055-1061, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34716798

ABSTRACT

The study on robot-assisted therapy in a pediatric field has not been applied sufficiently in clinical settings. The purpose of this pilot study is to explore the potential therapeutic effects of a group robot intervention (GRI), using dog-like social robot (SR) 'aibo' in pediatric ward. GRI by aibo was conducted for those children with chronic illness (127 in total) who are hospitalized in National Centre for Child Health and Development (NCCHD), and their caregivers (116 in total), from March to April 2018. The observer made structured behavioural observation records, based on which qualitative research on the features of their words and conducts, were carried out. As a result, first, during the GRI, about 2/3 of total expression by children were positive, while about 1/4 were negative or inappropriate. On the other hand, as seen in the 'change' group, those children who had originally responded with negative expression eventually came to express positive expression, while getting involved in a ternary relationship or participating in a session more than once. Secondly, as for the expression from the caregivers during the GRI, active expressions such as 'participation' and 'exploration' accounted for the 2/3, while 1/3 turned out to be rather placid expressions such as 'watch over' or 'encourage.'Conclusion: There has not been any precedent study on the features of words and conducts expressed by patients and their caregivers during the GRI by aibo. The outcome suggests that aibo could possibly be used as a tool for group robot-assisted therapy in the pediatric treatment setting. What is Known: • The study on robot-assisted therapy in a pediatric field has only just begun. • Though many kinds of social robot have been reportedly used so far, none has yet to be applied in clinical settings What is New: • Our study revealed the features of words and behaviour expressed by the patients and their caregivers, when dog-like social robot 'aibo' was used for a group robot intervention in the pediatric ward. • The outcome suggests that aibo could possibly be used as a tool for group robot-assisted therapy in the pediatric treatment setting.


Subject(s)
Caregivers , Robotics , Animals , Child , Dogs , Humans , Inpatients , Pilot Projects , Social Interaction
14.
J Biochem ; 169(5): 585-599, 2021 Jul 03.
Article in English | MEDLINE | ID: mdl-33386843

ABSTRACT

Synthetic binding proteins that have the ability to bind with molecules can be generated using various protein domains as non-antibody scaffolds. These designer proteins have been used widely in research studies, as their properties overcome the disadvantages of using antibodies. Here, we describe the first application of a phage display to generate synthetic binding proteins using a sweet protein, monellin, as a non-antibody scaffold. Single-chain monellin (scMonellin), in which two polypeptide chains of natural monellin are connected by a short linker, has two loops on one side of the molecule. We constructed phage display libraries of scMonellin, in which the amino acid sequence of the two loops is diversified. To validate the performance of these libraries, we sorted them against the folding mutant of the green fluorescent protein variant (GFPuv) and yeast small ubiquitin-related modifier. We successfully obtained scMonellin variants exhibiting moderate but significant affinities for these target proteins. Crystal structures of one of the GFPuv-binding variants in complex with GFPuv revealed that the two diversified loops were involved in target recognition. scMonellin, therefore, represents a promising non-antibody scaffold in the design and generation of synthetic binding proteins. We termed the scMonellin-derived synthetic binding proteins 'SWEEPins'.


Subject(s)
Carrier Proteins/chemistry , Peptide Library , Plant Proteins/chemistry , Ranunculales/chemistry , Carrier Proteins/genetics , Plant Proteins/genetics , Ranunculales/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/genetics
15.
JMA J ; 3(4): 287-294, 2020 Oct 15.
Article in English | MEDLINE | ID: mdl-33225099

ABSTRACT

Herewith, we review an updated progress of regenerative medical products using human embryonic stem cells (ESCs) in Japan. Two groups from Kyoto University and the National Center for Child Health and Development (NCCHD) established a novel derivation/cultivation system of ESCs for potential application in translational and clinical research. At the first stage of ESC derivation, murine feeder cells have been used in line with Japanese guidelines on public health associated with the implementation of the xenograft. To avoid exposure of ESCs to animal products in culture media, a xeno-free cultivating system has been established. Twelve ESCs (KhES-1, KhES-2, KhES-3, KhES-4, KhES-5, SEES-1, SEES-2, SEES-3, SEES-4, SEES-5, SEES-6, and SEES-7) are now available under a clinically relevant platform for industrially and clinically applicable regenerative medical products. NCCHD submitted an investigative new drug application to the Pharmaceuticals and Medical Devices Agency (PMDA) for using ESC-based products in patients with hyperammonemia due to genetic defects on March 2018 under the Pharmaceutical Affairs Law (now revised to the Pharmaceuticals, Medical Devices, and Other Therapeutic Products Act). Currently, up to ten ESC-based products are being prepared for intractable and rare disorders in Japan.

16.
Front Psychiatry ; 11: 477, 2020.
Article in English | MEDLINE | ID: mdl-32581866

ABSTRACT

BACKGROUND: Children who are exposed to natural disasters are at greater risk of developing mental and behavior problems. Prior studies have suggested that positive parenting practices could prevent child mental and behavior problems among those who were exposed to natural disasters. Parent-child interaction increases oxytocin level in parents and infants; however, studies assessing the change in oxytocin level after positive parent-child interaction and its effect on child behavior problems among preadolescents who were exposed to natural disasters are lacking. This study investigated whether playful interaction stimulated oxytocin levels in 34 mother-child dyads who experienced the 2011 Great East Japan Earthquake in Kesennuma City in Miyagi Prefecture, Japan, and the effect of the maternal oxytocin changes on child behavior problems. METHODS: Participants were recruited in 2012 after the Great East Japan Earthquake. Annual surveys were conducted from 2012 to 2017. Salivary oxytocin level was assessed before and after the playful interaction in 2015. Behavior problems were evaluated by caregivers, using the Child Behavior Checklist (CBCL) in 2017. Fixed effect regression analyses were conducted to determine the effect of playful mother-child interaction on oxytocin level by comparing the change in the 10 min after the interaction with the change in the 10 min before the interaction. We also examined the effect of maternal oxytocin changes before and after the playful interaction on the onset of child behavior problems in 2017. RESULTS: A significant increase in maternal oxytocin level was detected following playful interaction, especially among mothers of first-born boys (2.63 pg/mg protein. 95% CI: 0.45, 4.81). Maternal psychological distress and trauma were also negatively associated with an increase of oxytocin levels. The increase in maternal oxytocin level was significantly associated with lower externalizing problem score of children 2 years later. CONCLUSION: Our results might suggest a rational for potential preventive intervention for child behavior problems through playful mother-child interaction after natural disasters.

17.
Physiol Behav ; 197: 37-41, 2018 12 01.
Article in English | MEDLINE | ID: mdl-30290180

ABSTRACT

Although the involvement of two types of vasopressin (AVP) receptors, v1a and v1b, in neural regulation of social behavior is well documented in rodents, there is no report on combined actions of them in regulation of social behavior. In this study, we investigated behavioral differences between wild-type (WT) and v1a and v1b double knockout (dKO) mice. For this, we measured olfactory preference, sexual behavior with receptive females (four weekly tests) in an enriched large observation cage, and anxiety-like behaviors. No difference between WT and dKO mice was found in olfactory preferences for estrous female odor to male odor. Over all four mating tests, the number of mounts and pursuits after receptive females was significantly greater in dKO mice than in WT mice. In the elevated plus maze and the open field test, dKO mice showed lower anxiety-like behavior than WT mice. Finally, we measured approach behavior to several types of objects, figurines, and caged anestrous or estrous females placed in the open field apparatus. The only difference observed was that dKO mice spent longer in the vicinity of estrous females than did WT mice. These findings suggest that vasopressin receptors are involved in the regulation of sociosexual behavior, presumably partly mediated by emotional responses, in male mice.


Subject(s)
Anxiety/metabolism , Receptors, Vasopressin/metabolism , Sexual Behavior, Animal/physiology , Animals , Choice Behavior/physiology , Estrous Cycle , Exploratory Behavior/physiology , Female , Male , Mice, Inbred C57BL , Mice, Knockout , Olfactory Perception/physiology , Receptors, Vasopressin/genetics
18.
Biochem Biophys Res Commun ; 501(4): 988-995, 2018 07 02.
Article in English | MEDLINE | ID: mdl-29777700

ABSTRACT

Astrocytes, a large population of glial cells, detect neurotransmitters and respond by increasing intracellular Ca2+ concentration ([Ca2+]i) and releasing chemical molecules called gliotransmitters. Recently discovered Ca2+ influx through transient receptor potential ankyrin 1 (TRPA1) channels is reported to cause spontaneous [Ca2+]i increase in astrocytes. While several physiological functions of TRPA1-mediated spontaneous Ca2+ signal have been revealed, relation with gliotransmitter release, especially peptide hormone exocytosis is largely unknown. We therefore explored the [Ca2+]i and exocytosis dynamics in rat astrocyte cell line C6 cells and primary astrocytes. TRPA1-mediated spontaneous [Ca2+]i transients were observed in both C6 cells and primary astrocytes. Total internal reflection fluorescence microscopy revealed that Venus-tagged brain-derived neurotrophic factor and neuropeptide Y were released spontaneously from astrocytes. Activation of TRPA1 channels enhanced the frequency of peptide hormone exocytosis, and inhibition of TRPA1 channels decreased the number of peptide hormone exocytosis. These results suggest that TRPA1-mediated spontaneous [Ca2+]i increase modulates the spontaneous release of peptide hormones from astrocytes.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Neuropeptide Y/metabolism , TRPA1 Cation Channel/metabolism , Animals , Astrocytes/metabolism , Calcium/metabolism , Cells, Cultured , Exocytosis , Rats , TRPA1 Cation Channel/agonists
19.
J Biol Chem ; 292(26): 10855-10864, 2017 06 30.
Article in English | MEDLINE | ID: mdl-28533434

ABSTRACT

The lysophosphatidylinositol (LPI) has crucial roles in multiple physiological processes, including insulin exocytosis from pancreatic islets. However, the role of LPI in secretion of glucagon-like peptide-1 (GLP-1), a hormone that enhances glucose-induced insulin secretion, is unclear. Here, we used the murine enteroendocrine L cell line GLUTag and primary murine small intestinal cells to elucidate the mechanism of LPI-induced GLP-1 secretion. Exogenous LPI addition increased intracellular Ca2+ concentrations ([Ca2+] i ) in GLUTag cells and induced GLP-1 secretion from both GLUTag and acutely prepared primary intestinal cells. The [Ca2+] i increase was suppressed by an antagonist for G protein-coupled receptor 55 (GPR55) and by silencing of GPR55 expression, indicating involvement of Gq and G12/13 signaling pathways in the LPI-induced increased [Ca2+] i levels and GLP-1 secretion. However, GPR55 agonists did not mimic many of the effects of LPI. We also found that phospholipase C inhibitor and Rho-associated kinase inhibitor suppressed the [Ca2+] i increase and that LPI increased the number of focal adhesions, indicating actin reorganization. Of note, blockage or silencing of transient receptor potential cation channel subfamily V member 2 (TRPV2) channels suppressed both the LPI-induced [Ca2+] i increase and GLP-1 secretion. Furthermore, LPI accelerated TRPV2 translocation to the plasma membrane, which was significantly suppressed by a GPR55 antagonist. These findings suggest that TRPV2 activation via actin reorganization induced by Gq and G12/13 signaling is involved in LPI-stimulated GLP-1 secretion in enteroendocrine L cells. Because GPR55 agonists largely failed to mimic the effects of LPI, its actions on L cells are at least partially independent of GPR55 activation.


Subject(s)
Calcium Channels/metabolism , Calcium Signaling/physiology , Enteroendocrine Cells/metabolism , Glucagon-Like Peptide 1/metabolism , Lysophospholipids/metabolism , TRPV Cation Channels/metabolism , Animals , Calcium Channels/genetics , Cells, Cultured , Focal Adhesions/genetics , Focal Adhesions/metabolism , GTP-Binding Protein alpha Subunits/genetics , GTP-Binding Protein alpha Subunits/metabolism , Glucagon-Like Peptide 1/genetics , Mice , Protein Transport/physiology , Receptors, Cannabinoid/genetics , Receptors, Cannabinoid/metabolism , TRPV Cation Channels/genetics
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