RESUMO
Recent studies provide evidence to support that cluster of differentiation 38 (CD38) and CD157 meaningfully act in the brain as neuroregulators. They primarily affect social behaviors. Social behaviors are impaired in Cd38 and Cd157 knockout mice. Single-nucleotide polymorphisms of the CD38 and CD157/BST1 genes are associated with multiple neurological and psychiatric conditions, including autism spectrum disorder, Parkinson's disease, and schizophrenia. In addition, both antigens are related to infectious and immunoregulational processes. The most important clues to demonstrate how these molecules play a role in the brain are oxytocin (OT) and the OT system. OT is axo-dendritically secreted into the brain from OT-containing neurons and causes activation of OT receptors mainly on hypothalamic neurons. Here, we overview the CD38/CD157-dependent OT release mechanism as the initiation step for social behavior. The receptor for advanced glycation end-products (RAGE) is a newly identified molecule as an OT binding protein and serves as a transporter of OT to the brain, crossing over the blood-brain barrier, resulting in the regulation of brain OT levels. We point out new roles of CD38 and CD157 during neuronal development and aging in relation to nicotinamide adenine dinucleotide+ levels in embryonic and adult nervous systems. Finally, we discuss how CD38, CD157, and RAGE are crucial for social recognition and behavior in daily life.
Assuntos
ADP-Ribosil Ciclase 1/metabolismo , ADP-Ribosil Ciclase/metabolismo , Antígenos CD/metabolismo , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Comportamento Social , Animais , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/metabolismo , Biomarcadores , Encéfalo/metabolismo , Sinalização do Cálcio , Ativação Enzimática , Proteínas Ligadas por GPI/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Estudos de Associação Genética , Humanos , Imuno-Histoquímica , Camundongos Knockout , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Ocitocina , Polimorfismo de Nucleotídeo Único , RNA Mensageiro/genética , Receptor para Produtos Finais de Glicação Avançada/genética , Canais de Cátion TRPM/metabolismoRESUMO
We investigated the effects of nanosized TiO2 particles on the death of mouse leukemia L1210 cells. TiO2 particles suppressed proliferation and induced cell death, as measured by lactate dehydrogenase (LDH) release into the culture medium. Chromatin condensation, which is typical of the initiation of cell death, was observed in approximately 14% cells cultured with titanium dioxide (TiO2) particles for 12 h. Furthermore, giant DNA fragments of approximately 2 Mbp and high-molecular-weight DNA fragments between 100 kbp and 1 Mbp were observed in cells cultured for 18 h with TiO2 particles. These giant and high-molecular-weight DNA fragments were further degraded into smaller DNA fragments, appearing as DNA ladders. Corresponding to the generation of DNA fragments, caspase-3 activity increased in cells treated with TiO2 particles. TiO2 particle-induced LDH release was not inhibited by cytochalasin D, an inhibitor of endocytosis. These results suggest that nanosized TiO2 particles can induce apoptosis associated with DNA fragmentation and caspase-3 activation and that TiO2 particle-induced apoptosis is not caused by endocytosis but is associated with contact of the particles with the cell surface.
Assuntos
Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Leucemia L1210/patologia , Nanopartículas Metálicas/toxicidade , Animais , Materiais Biocompatíveis/toxicidade , Células Cultivadas , Citocalasina D/farmacologia , Ativação Enzimática , L-Lactato Desidrogenase/metabolismo , Leucemia L1210/tratamento farmacológico , Leucemia L1210/metabolismo , Camundongos , Titânio/toxicidadeAssuntos
Cálcio/metabolismo , ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/química , Sistemas do Segundo Mensageiro , Animais , Encéfalo/efeitos dos fármacos , Sinalização do Cálcio , ADP-Ribose Cíclica/síntese química , Desenho de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Células Jurkat , Microssomos/efeitos dos fármacos , Conformação Molecular , Nucleotídeos/química , Ratos , Estereoisomerismo , Compostos de Sulfidrila/químicaRESUMO
A 16-kDa proteolipid, mediatophore, in Torpedo electric organs mediates Ca(2+)-dependent acetylcholine release. Mediatophore is identical to the pore-forming stalk c-subunit of the V0 sector of vacuolar proton ATPase (ATP6V0C). The function of ATP6V0C in the mammalian central nervous system is not clear. Here, we report transfection of adeno-associated viral vectors harboring rat ATP6V0C into the mouse substantia nigra, in which high potassium stimulation increased overflow of endogenous dopamine (DA) measured in the striatum by in vivo microdialysis. Next, in the striatum of 6-hydroxydopamine-lesioned mice, a model of Parkinson's disease (PD), human tyrosine hydroxylase, aromatic l-amino-acid decarboxylase and guanosine triphosphate cyclohydrolase 1, together with or without ATP6V0C, were expressed in the caudoputamen for rescue. Motor performance on the accelerating rotarod test and amphetamine-induced ipsilateral rotation were improved in the rescued mice coexpressing ATP6V0C. [(3)H]DA, taken up into cultured N18 neuronal tumor cells transformed to express ATP6V0C, was released by potassium stimulation. These results indicated that ATP6V0C mediates DA release from nerve terminals in the striatum of DA neurons of normal mice and from gene-transferred striatal cells of parkinsonian mice. The results suggested that ATP6V0C may be useful as a rescue molecule in addition to DA-synthetic enzymes in the gene therapy of PD.
Assuntos
Comportamento Animal , Dopamina/metabolismo , Neuroblastoma/metabolismo , Doença de Parkinson/fisiopatologia , ATPases Vacuolares Próton-Translocadoras/metabolismo , Animais , Linhagem Celular Tumoral , Masculino , Camundongos , Camundongos Endogâmicos ICR , Microdiálise , Neuroblastoma/enzimologia , Neuroblastoma/patologiaRESUMO
The neurobiological basis of autism spectrum disorder (ASD) remains poorly understood. Given the role of CD38 in social recognition through oxytocin (OT) release, we hypothesized that CD38 may play a role in the etiology of ASD. Here, we first examined the immunohistochemical expression of CD38 in the hypothalamus of post-mortem brains of non-ASD subjects and found that CD38 was colocalized with OT in secretory neurons. In studies of the association between CD38 and autism, we analyzed 10 single nucleotide polymorphisms (SNPs) and mutations of CD38 by re-sequencing DNAs mainly from a case-control study in Japan, and Caucasian cases mainly recruited to the Autism Genetic Resource Exchange (AGRE). The SNPs of CD38, rs6449197 (p<0.040) and rs3796863 (p<0.005) showed significant associations with a subset of ASD (IQ>70; designated as high-functioning autism (HFA)) in the U.S. 104 AGRE family trios, but not with Japanese 188 HFA subjects. A mutation that caused tryptophan to replace arginine at amino acid residue 140 (R140W; (rs1800561, 4693C>T)) was found in 0.6-4.6% of the Japanese population and was associated with ASD in the smaller case-control study. The SNP was clustered in pedigrees in which the fathers and brothers of T-allele-carrier probands had ASD or ASD traits. In this cohort OT plasma levels were lower in subjects with the T allele than in those without. One proband with the T allele who was taking nasal OT spray showed relief of symptoms. The two variant CD38 poloymorphysms tested may be of interest with regard of the pathophysiology of ASD.
Assuntos
ADP-Ribosil Ciclase 1/genética , Transtornos Globais do Desenvolvimento Infantil/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Idoso , Análise de Variância , Encéfalo/metabolismo , Encéfalo/patologia , Criança , Pré-Escolar , Estudos de Coortes , Comparação Transcultural , Saúde da Família , Feminino , Frequência do Gene , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Técnicas Imunoenzimáticas/métodos , Japão , Masculino , Pessoa de Meia-Idade , Ocitocina/sangue , Vasopressinas/sangue , Adulto JovemRESUMO
Locally released oxytocin (OT) activates OT receptors (2.1:OXY:1:OT:) in neighboring neurons in the hypothalamus and their terminals in the posterior pituitary, resulting in further OT release, best known in autoregulation occurring during labor or milk ejection in reproductive females. OT also plays a critical role in social behavior of non-reproductive females and even in males in mammals from rodents to humans. Social behavior is disrupted when elevation of free intracellular Ca(2+) concentration ([Ca(2+)](i)) and OT secretion are reduced in male and female CD38 knockout mice. Therefore, it is interesting to investigate whether ADP-ribosyl cyclase-dependent signaling is involved in OT-induced OT release for social recognition in males, independent from female reproduction, and to determine its molecular mechanism. Here, we report that ADP-ribosyl cyclase activity was increased by OT in crude membrane preparations of the hypothalamus and posterior pituitary in male mice, and that OT elicited an increase in [Ca(2+)](i) in the isolated terminals over a period of 5 min. The increases in cyclase and [Ca(2+)](i) were partially inhibited by nonspecific protein kinase inhibitors and a protein kinase C specific inhibitor, calphostin C. Subsequently, OT-induced OT release was also inhibited by calphostin C to levels inhibited by vasotocin, an OT receptor antagonist, and 8-bromo-cADP-ribose. These results demonstrate that OT receptors are functionally coupled to membrane-bound ADP-ribosyl cyclase and/or CD38 and suggest that cADPR-mediated intracellular calcium signaling is involved in autoregulation of OT release, which is sensitive to protein kinase C, in the hypothalamus and neurohypophysis in male mice.
Assuntos
ADP-Ribosil Ciclase/metabolismo , Cálcio/metabolismo , ADP-Ribose Cíclica/metabolismo , Hipotálamo/metabolismo , Ocitocina , Neuro-Hipófise/efeitos dos fármacos , Neuro-Hipófise/metabolismo , Animais , Hipotálamo/citologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Ocitocina/metabolismo , Ocitocina/farmacologia , Neuro-Hipófise/citologia , Terminações Pré-Sinápticas/metabolismo , Fatores de TempoRESUMO
beta-NAD(+) is as abundant as ATP in neuronal cells. beta-NAD(+) functions not only as a coenzyme but also as a substrate. beta-NAD(+)-utilizing enzymes are involved in signal transduction. We focus on ADP-ribosyl cyclase/CD38 which synthesizes cyclic ADP-ribose (cADPR), a universal Ca(2+) mobilizer from intracellular stores, from beta-NAD(+). cADPR acts through activation/modulation of ryanodine receptor Ca(2+) releasing Ca(2+) channels. cADPR synthesis in neuronal cells is stimulated or modulated via different pathways and various factors. Subtype-specific coupling of various neurotransmitter receptors with ADP-ribosyl cyclase confirms the involvement of the enzyme in signal transduction in neurons and glial cells. Moreover, cADPR/CD38 is critical in oxytocin release from the hypothalamic cell dendrites and nerve terminals in the posterior pituitary. Therefore, it is possible that pharmacological manipulation of intracellular cADPR levels through ADP-ribosyl cyclase activity or synthetic cADPR analogues may provide new therapeutic opportunities for treatment of neurodevelopmental disorders.
Assuntos
Química Encefálica/fisiologia , Sinalização do Cálcio/fisiologia , ADP-Ribose Cíclica/metabolismo , Sistema Nervoso/metabolismo , ADP-Ribosil Ciclase/metabolismo , Animais , Humanos , Sistema Hipotálamo-Hipofisário/metabolismo , NAD/metabolismo , Ocitocina/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Ras-GTPase-activating proteins (Ras-GAPs) have been implicated both as suppressors of Ras and as effectors in regulating cellular activities. To study whether Ras-GAPs have roles in tumor cell survival or not, mRNA levels of ras-related genes were measured in v-Ki-ras-transformed (DT) and the parental NIH/3T3 cells, using real-time PCR. mRNA levels of p120-Gap, Gap1(m), and PIK3CA were increased in DT cells compared with NIH/3T3 cells. p120-Gap and PIK3CA genes were induced by addition of serum or epidermal growth factor to serum-starved DT cells. Three anti-cancer drugs, an ERK kinase (MEK) inhibitor PD98059, a topoisomerase II poison doxorubicin (adriamycin), and a histone deacetylase inhibitor trichostatin A, selectively blocked the overexpression of p120-Gap and Gap1(m) genes in DT cells. These drugs also caused reversion of DT cells to the adherent shape associated with growth arrest. Our results suggest that p120-Gap and Gap1(m) genes provide important biomarkers for cancer therapies.
Assuntos
Doxorrubicina/farmacologia , Genes ras/fisiologia , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Regulação para Cima/efeitos dos fármacos , Proteínas Ativadoras de ras GTPase/metabolismo , Células 3T3 , Animais , Linhagem Celular Transformada , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Ativadoras de ras GTPase/genéticaRESUMO
CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.
Assuntos
ADP-Ribosil Ciclase 1/metabolismo , Comportamento Materno/fisiologia , Ocitocina/metabolismo , Comportamento Social , ADP-Ribosil Ciclase 1/deficiência , ADP-Ribosil Ciclase 1/genética , Amnésia/genética , Amnésia/metabolismo , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Feminino , Regulação da Expressão Gênica , Humanos , Injeções , Masculino , Memória/fisiologia , Camundongos , Atividade Motora/fisiologia , Ocitocina/administração & dosagem , Ocitocina/sangue , Ocitocina/farmacologia , Vasopressinas/sangueRESUMO
The role of cyclic ADP-ribose (cADPR) and its synthetic enzyme, CD38, as a downstream signal of muscarinic acetylcholine receptors (mAChRs) was examined in neuroblastoma cells expressing M1 mAChRs (NGM1). NGM1 cells were further transformed with both wild-type and mutant (C119K/C201E) human CD38. The dual transformed cells exhibited higher cADPR formation than ADPR production and elevated intracellular free Ca(2+) concentrations ([Ca(2+)](i)) in response to ACh. These phenotypes were analyzed in detail in a representative CD38 clone. The intracellular cADPR concentration by ACh application was significantly increased by CD38 overexpression. Digital image analysis by a confocal microscopy revealed that topographical distribution of the sites of Ca(2+) release was unchanged between control and overexpressed cells. These results indicate that cADPR is an intracellular messenger of Ca(2+) signalling, suggesting that CD38 can contribute to mAChR-cADPR signalling.
Assuntos
ADP-Ribosil Ciclase 1/metabolismo , ADP-Ribosil Ciclase/metabolismo , Acetilcolina/metabolismo , Sinalização do Cálcio/fisiologia , ADP-Ribose Cíclica/metabolismo , Receptores Muscarínicos/metabolismo , ADP-Ribosil Ciclase 1/genética , Acetilcolina/farmacologia , Animais , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Linhagem Celular Tumoral , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Humanos , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fenótipo , Ratos , Receptores Muscarínicos/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologiaRESUMO
ADP-ribosyl cyclase activity in the crude membrane fraction of neuroblastomaxglioma NGPM1-27 hybrid cells was measured by monitoring [(3)H] cyclic ADP-ribose (cADPR) formation from [(3)H] NAD(+). Bradykinin (BK) at 100nM increased ADP-ribosyl cyclase activity by about 2.5-fold. Application of 300nM BK to living NGPM1-27 cells decreased NAD(+) to 78% of the prestimulation level at 30s. In contrast, intracellular cADPR concentrations were increased by 2-3-fold during the period from 30 to 120s after the same treatment. Our results suggest that cADPR is one of the second messengers downstream of B(2) BK receptors.
Assuntos
ADP-Ribosil Ciclase/metabolismo , Bradicinina/farmacologia , Linhagem Celular Tumoral/efeitos dos fármacos , ADP-Ribose Cíclica/metabolismo , NAD/metabolismo , Vasodilatadores/farmacologia , Animais , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células Híbridas/citologia , Células Híbridas/efeitos dos fármacos , Camundongos , Neuroblastoma , Ratos , Sistemas do Segundo Mensageiro/fisiologiaRESUMO
We synthesized analogs modified in the ribose unit (ribose linked to N1 of adenine) of cyclic ADP-ribose (cADPR), a Ca2+-mobilizing second messenger. The biological activities of these analogs were determined in NG108-15 neuroblastoma x glioma hybrid cells that were pre-loaded with fura-2 acetoxymethylester and subjected to whole-cell patch-clamp. Application of the hydrolysis-resistant cyclic ADP-carbocyclic-ribose (cADPcR) through patch pipettes potentiated elevation of the cytoplasmic free Ca2+ concentration ([Ca2+]i) at the depolarized membrane potential. The increase in [Ca2+]i evoked upon sustained membrane depolarization was significantly larger in cADPcR-infused cells than in non-infused cells and its degree was equivalent to or significantly greater than that induced by cADPR or beta-NAD+. 8-Chloro-cADPcR and two inosine congeners (cyclic IDP-carbocyclic-ribose and 8-bromo-cyclic IDP-carbocyclic-ribose) did not induce effects similar to those of cADPcR or cADPR. Instead, 8-chloro-cADPcR together with cADPR or cADPcR caused inhibition of the depolarization-induced [Ca2+]i increase as compared with either cADPR or cADPcR alone. These results demonstrated that our cADPR analogs have agonistic or antagonistic effects on the depolarization-induced [Ca2+]i increase and suggested the presence of functional reciprocal coupling between ryanodine receptors and voltage-activated Ca2+ channels via cADPR in mammalian neuronal cells.
Assuntos
Cálcio/metabolismo , ADP-Ribose Cíclica/farmacologia , Citoplasma/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Rianodina/farmacologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Linhagem Celular , ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/síntese química , Citoplasma/metabolismo , Relação Dose-Resposta a Droga , Interações Medicamentosas , Estimulação Elétrica/métodos , Fura-2/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/efeitos da radiação , Camundongos , Inibição Neural/efeitos dos fármacos , Inibição Neural/fisiologia , Neuroblastoma , Neurônios/fisiologia , Neurônios/efeitos da radiação , Nifedipino/farmacologia , Técnicas de Patch-Clamp/métodos , Rutênio/farmacologiaRESUMO
We previously developed cyclic ADP-carbocyclic ribose (cADPcR, 2) as a stable mimic of cyclic ADP-ribose (cADPR, 1), a Ca(2+)-mobilizing second messenger. A series of the N1-ribose modified cADPcR analogues, designed as novel stable mimics of cADPR, which were the 2"-deoxy analogue 3, the 3"-deoxy analogue 4, the 3"-deoxy-2"-O-(methoxymethyl) analogue 5, the 3"-O-methyl analogue 6, the 2",3"-dideoxy analogue 7, and the 2",3"-dideoxydidehydro analogue 8, were successfully synthesized using the key intramolecular condensation reaction with phenylthiophosphate-type substrates. We investigated the conformations of these analogues and of cADPR and found that steric repulsion between both the adenine and N9-ribose moieties and between the adenine and N1-ribose moieties was a determinant of the conformation. The Ca(2+)-mobilizing effects were evaluated systematically using three different biological systems, i.e., sea urchin eggs, NG108-15 neuronal cells, and Jurkat T-lymphocytes. The relative potency of Ca(2+)-mobilization by these cADPR analogues varies depending on the cell-type used: e.g., 3"-deoxy-cADPcR (4) > cADPcR (2) > cADPR (1) in sea urchin eggs; cADPR (1) >> cADPcR (2) approximately 3"-deoxy-cADPcR (4) in T-cells; and cADPcR (2) > cADPR (1) > 3"-deoxy-cADPcR (4) in neuronal cells, respectively. These indicated that the target proteins and/or the mechanism of action of cADPR in sea urchin eggs, T-cells, and neuronal cells are different. Thus, this study represents an entry to cell-type selective cADPR analogues, which can be used as biological tools and/or novel drug leads.
Assuntos
Sinalização do Cálcio/efeitos dos fármacos , ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/síntese química , Animais , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/farmacologia , ADP-Ribose Cíclica/química , ADP-Ribose Cíclica/farmacologia , Humanos , Conformação Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óvulo/efeitos dos fármacos , Óvulo/metabolismo , Ouriços-do-Mar , Relação Estrutura-Atividade , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismoRESUMO
Cyclic ADP-ribose (cADP-ribose) is a putative second messenger or modulator. However, the role of cADP-ribose in the downstream signals of the metabotropic glutamate receptors (mGluRs) is unclear. Here, we show that glutamate stimulates ADP-ribosyl cyclase activity in rat or mouse crude membranes of retina via group III mGluRs or in superior cervical ganglion via group I mGluRs. The retina of mGluR6-deficient mice showed no increase in the ADP-ribosyl cyclase level in response to glutamate. GTP enhanced the initial rate of basal and glutamate-stimulated cyclase activity. GTP-gamma-S also stimulated basal activity. To determine whether the coupling mode of mGluRs to ADP-ribosyl cyclase is a feature common to individual cloned mGluRs, we expressed each mGluR subtype in NG108-15 neuroblastoma x glioma hybrid cells. The glutamate-induced stimulation of the cyclase occurs preferentially in NG108-15 cells over-expressing mGluRs1, 3, 5, and 6. Cells expressing mGluR2 or mGluRs4 and 7 exhibit inhibition or no coupling, respectively. Glutamate-induced activation or inhibition of the cyclase activity was eliminated after pre-treatment with cholera or pertussis toxin, respectively. Thus, the subtype-specific coupling of mGluRs to ADP-ribosyl cyclase via G proteins suggests that some glutamate-evoked neuronal functions are mediated by cADP-ribose.
Assuntos
ADP-Ribosil Ciclase/metabolismo , Glioma/metabolismo , Neuroblastoma/metabolismo , Neurônios/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Retina/metabolismo , Gânglio Cervical Superior/metabolismo , ADP-Ribosil Ciclase/química , ADP-Ribosil Ciclase/efeitos dos fármacos , Adenosina Difosfato Ribose/biossíntese , Animais , Membrana Celular/enzimologia , Células Cultivadas , Toxina da Cólera/farmacologia , Ativação Enzimática/efeitos dos fármacos , Glioma/química , Ácido Glutâmico/farmacologia , Guanosina Trifosfato/análogos & derivados , Guanosina Trifosfato/farmacologia , Camundongos , Camundongos Knockout , Neuroblastoma/química , Neurônios/química , Neurônios/citologia , Ratos , Ratos Wistar , Retina/química , Retina/citologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Gânglio Cervical Superior/química , Gânglio Cervical Superior/citologiaRESUMO
Hepatoma cell lines can produce a massive amount of chemokines in response to various stimuli including hepatitis viruses and their products. However, it remains elusive on the types of chemokine receptor(s) expressed in the hepatoma tissues and its roles in hepatoma development. To clarify these points, we examined the chemokine receptor expression in six human hepatoma cell lines. All of the hepatoma cell lines constitutively and exclusively expressed CCR1 mRNA and its protein on their cell surface. CCR1 expression was also detected on hepatoma cells and to a lesser degree, on endothelial cells in hepatoma tissues but not in normal liver tissues. Furthermore, CCL3 expression was detected in hepatoma cells, endothelial cells, and to a lesser degree, fibroblast-like cells in hepatoma tissue, whereas only occasional vascular endothelial cells and inflammatory cells in normal liver tissues were weakly positive for CCL3. Moreover, the forskolin-mediated increases in intracellular cAMP concentrations were inhibited by the ligands for CCR1, CCL3, CCL4, and CCL5, suggesting that the expressed CCR1 was functional. Four hepatoma cell lines produced CCL3 only in response to interleukin (IL)-1 alpha and IL-1 beta. Finally, IL-1 alpha and IL-1 beta were detected abundantly in hepatoma tissues but not in normal liver tissues. Thus, IL-1 may enhance the local production of CCL3, which may interact with CCR1 expressed on hepatoma cells, in an autocrine and/or paracrine manner.