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At least 127 records · Page 7Linked to original sources
PubMed2000

Phylogeny of ips DeGeer species (Coleoptera: scolytidae) inferred from mitochondrial cytochrome oxidase I DNA sequence.

We used 766 bp of DNA sequence data from the mitochondrial cytochrome oxidase I gene to reconstruct a phylogeny for 39 of 43 Ips species, many of which are economically important bark beetles. The phylogeny was reconstructed using equally weighted and weighted parsimony. In both analyses, peripheral clades were well supported while internal clades were poorly supported. Phylogenetic analysis of translated amino acids produced a poorly resolved tree that was discordant with trees reconstructed with nucleotide sequence data. Two main conclusions are drawn about the monophyly of Ips and traditional systematic groups within Ips. First, Ips is monophyletic only when I. mannsfeldi, I. nobilis, and the concinnus and latidens species groups are excluded. The latidens group, I. mannsfeldi, and I. nobilis form a monophyletic group with 3 Orthotomicus species, while the concinnus group has a more basal position. Second, the majority of the species groups in the current classification for Ips are not monophyletic. European Ips species do not form a monophyletic group, contrary to common usage, and are dispersed on the phylogenetic tree among North American species. These results indicate that a formal systematic revision of Ips is needed.

Animals↗
PubMed1991

Dopamine D2-receptors mediate hypothermia in mice: ICV and IP effects of agonists and antagonists.

The effect of centrally and peripherally administered dopamine D1 and D2 specific compounds on core body temperature in mice was investigated. Quinpirole (LY-17155), a D2 agonist, induced a dose-dependent fall in body temperature (2.4-11.6%; p less than 0.003) when injected intraperitoneally (ip, 0.3-3.0 mg/kg) and intracerebroventricularly (icv, 0.1 mg/kg). This quinpirole-induced (1.0 mg/kg, ip) hypothermia was reversed by the central and peripheral administration of the D2 antagonists S-(-)-sulpiride (3.0-30.0 mg/kg, ip; 0.1-3.0 mg/kg, icv) and spiperone (0.03 and 0.1 mg/kg, ip; 0.03-3.0 mg/kg, icv). Domperidone, a D2 antagonist which does not cross the blood brain barrier, had no effect on quinpirole-induced hypothermia (1.0-10.0 mg/kg, ip). Domperidone partially reversed quinpirole-induced hypothermia at 0.1-30.0 mg/kg, icv. The D1 agonist, SKF-38393 at a high dose of 10.0 mg/kg, ip mildly attenuated quinpirole-induced hypothermia (a 1.8% increase in temperature). SKF-38393 at 10.0 mg/kg, icv potentiated quinpirole-induced hypothermia. SCH-23390 (0.1-3.0 mg/kg, ip), a D1 antagonist, had no effect on quinpirole-induced hypothermia and potentiated the hypothermia when administered icv. An ineffective icv dose of spiperone (0.01 mg/kg) in reversing quinpirole-induced hypothermia was rendered effective by prior administration of SCH-23390 (0.1-3.0 mg/kg, icv) but not by SKF-38393 (1.0-10.0 mg/kg, icv). These data suggest a central D2 receptor mechanism mediating hypothermia in mice which is capable of being modulated by the D1 receptor.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Sensitization and individual differences to IP amphetamine, cocaine, or caffeine following repeated intracranial amphetamine infusions.

Rats that have a high locomotor response to novelty (HR) sensitize more readily to IP-administered amphetamine than rats with a low locomotor response (LR) to novelty. This experiment compared sensitization in HR and LR rats following amphetamine (3.0 micrograms/side for 5 days) infused bilaterally into either the nucleus accumbens (NACC), ventral tegmental area (VTA), or the medial frontal cortex (MFC). The subsequent locomotor response to IP-administered d-amphetamine sulfate (1 mg/kg), cocaine HCl (15 mg/kg), and caffeine benzoate (20 mg/kg) was also examined. No differences were observed between HR and LR rats following amphetamine infusion into either the MFC, NACC, or VTA. However, HR rats showed greater locomotor activity compared to LR rats following either IP amphetamine, cocaine, or caffeine for subjects cannulated in the NACC, MFC, or the VTA. Repeated infusions of amphetamine into the VTA increased the locomotor response to both IP amphetamine and cocaine, but not to IP caffeine, while repeated infusions of amphetamine into the NACC or MFC had no effect on locomotor response to any drug subsequently administered IP. The results support previous findings that changes induced by intra-VTA infusions, but not intra-NACC or MFC infusions, of amphetamine induce sensitization to IP-administered amphetamine and cocaine. Findings from the present experiment indicate the ability of the dopamine cell body region, but not the dopamine terminal fields, to produce locomotor sensitization to amphetamine and cocaine. The results from the present experiment also indicate the lack of localization to one of studied regions of individual differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphetamine↗
PubMed1991

Oral (po) dosing with RSU 1069 or RB 6145 maintains their potency as hypoxic cell radiosensitizers and cytotoxins but reduces systemic toxicity compared with parenteral (ip) administration in mice.

RB 6145 is a pro-drug of the hypoxic cell radiosensitizer RSU 1069 with reduced systemic toxicity. The maximum tolerated dose (MTD) of RSU 1069 for C3H/He mice was 80 mg/kg (0.38 mmol/kg) ip but 320 mg/kg (1.5 mmol/kg) following po administration. The MTD values of RB 6145 were 350 mg/kg (0.94 mmol/kg) ip and 1 g/kg (2.67 mmol/kg) po. Toxicity of RSU 1069 toward bone marrow stem cells was also less after po administration than after ip administration; 0.1 mmol/kg ip RSU 1069 and 0.38 mmol/kg po RSU 1069 both reduced the surviving fraction of clonogenic CFU-A cells by 50%. Oral administration of RSU 1069 resulted in lower spermatogenic toxicity. No loss of intestinal crypts was detected after ip or po administration of RSU 1069. Some nephrotoxicity was observed in half of the mice given the highest po dose of 1.5 mmol/kg of RSU 1069; this was not observed following the highest ip dose of drug. For RSU 1069 and RB 6145, administered by either route, the maximum hypoxic cell radiosensitization in murine KHT sarcomas, occurred when the drugs were given 45-60 min before 10 Gy of X rays. The degree of radiosensitization produced by a particular dose of either compound was largely independent of the route of administration. Preliminary pharmacokinetic studies, using 3H-RSU 1069, suggested that anti-tumor efficacy correlated with peak blood level of label and concentration in the tumor at the time of irradiation, which were not reduced by po compared with ip administration. Normal tissue toxicity tended to correlate with total exposure over time, which was reduced approximately two-fold by po administration. Oral administration of RSU 1069 or RB 6145, as well as being convenient, may give therapeutic benefit since dose-limiting toxicity in mice was reduced compared with parenteral administration, whereas radiosensitizing activity was less affected.

Administration, Oral↗
PubMed1998

Lipopolysaccharide-induced expression of IP-10 mRNA in rat brain and in cultured rat astrocytes and microglia.

Using mRNA differential display technique, we have found a differentially expressed band in rat brain, designated HAP2G1, which was the strongest one induced in response to peripheral administration of lipopolysaccharide (LPS). Sequence analysis showed that HAP2G1 cDNA is the rat homologue of the human alpha-chemokine IP-10. Using RT-PCR technique and in situ hybridization, we demonstrate that IP-10 mRNA was expressed only in brain tissue of rats treated with LPS and not in control brain tissue. Using semi-quantitative PCR, we found that both cultured astrocytes and microglia express IP-10 mRNA after treatment with LPS. LPS-induced IP-10 mRNA reached peak levels in rat brain and in cultured microglia at approximately 3 h after treatment with LPS. At 10 h, IP-10 mRNA was markedly decreased, and at 24 h it was low but still detectable by PCR or in situ hybridization. In contrast to unstimulated microglia, unstimulated astrocytes constitutively expressed IP-10 mRNA at a low level. Increased IP-10 expression could possibly be involved in the microglia response to inflammatory stimuli in vivo.

Animals↗
PubMed2001

The effects of the statins lovastatin and cerivastatin on signalling by the prostanoid IP-receptor.

The prostanoid-IP receptor may be unique among G protein coupled receptors in that it is isoprenylated. In this study, we investigated the effects of the statins lovastatin and cerivastatin on signalling by the mouse (m) IP and the human (h) IP receptors, over-expressed in human embryonic kidney (HEK) 293 cells and by the hIP receptor, endogenously expressed in human erythroleukaemia cells. Both statins significantly reduced IP receptor-mediated cyclic AMP generation and intracellular calcium ([Ca(2+)](i)) mobilization in a time and concentration dependent manner but had no effect on signalling by the non-isoprenylated beta(2) adrenergic receptor or by the human prostanoid-TP receptor isoforms. Cerivastatin (IC(50), 50 - 90 nM) was significantly more potent than lovastatin (IC(50), 0.80 - 4.2 microM) in inhibiting IP receptor signalling. Whereas IC(50) values indicated that the hIP receptor was significantly more sensitive than the mIP receptor to the statins, the extent of inhibition of cyclic AMP generation by the mIP receptor was significantly greater than that of the hIP receptor to either statin, even at the highest concentrations used. Pretreatment with either statin significantly reduced IP receptor mediated desensitization of signalling by the h.TPalpha, but not by the h.TPbeta, receptor isoform. These data generated in whole cells point to the possibility that statin therapy may interfere with IP receptor signalling in vivo; such interference may be extenuated under conditions where circulating statin levels are elevated and may account, in part, for some of the pleiotropic affects of the statins not attributed solely to their lipid lowering properties.

Anticholesteremic Agents↗
PubMed2002

Augmentation of allergic inflammation in prostanoid IP receptor deficient mice.

1 To evaluate the role of prostaglandin I(2) (PGI(2)) in allergic inflammation, allergic responses in the airway, skin and T cells were studied in mice lacking the receptor for PGI(2) (the prostanoid IP receptor) through gene disruption. 2 Three inhalations of antigen caused an increase in plasma extravasation, leukocyte accumulation and cytokine (interleukin (IL)-4 and IL-5) production in the airway of sensitized mice. These airway inflammatory responses were significantly greater in IP receptor deficient mice than in wild-type mice. 3 The vascular leakage caused by passive cutaneous anaphylaxis, substance P and 5-hydroxytryptamine was markedly increased in the skin of IP receptor deficient mice, compared with comparably treated wild-type mice. 4 The inhalation of antigen in sensitized mice resulted in increased serum antigen specific IgE, total IgE and IgG levels. The magnitude of the elevations of each immunoglobulin level in IP receptor deficient mice is notably higher than that in wild-type mice. To elucidate the mechanism of an enhancement of immunoglobulin production, the activity of T cells in sensitized and non-sensitized mice was studied by means of the production of cytokines. The antigen-induced IL-4 production by spleen cells from sensitized IP receptor deficient mice was almost three times greater than that in wild-type mice. On the contrary, the anti-CD3 antibody-induced interferon-gamma production by CD4(+) T cells from non-sensitized IP receptor deficient mice was significantly lower than that in wild-type mice. 5 The present data indicate that IP receptor deficiency reinforced an allergic airway and skin inflammation by augmentation of vascular permeability increase and the T helper 2 cell function. These findings suggest a regulatory role of PGI(2) in allergic inflammation.

Animals↗
PubMed2006

RO1138452 and RO3244794: characterization of structurally distinct, potent and selective IP (prostacyclin) receptor antagonists.

Prostacyclin (PGI2) possesses various physiological functions, including modulation of nociception, inflammation and cardiovascular activity. Elucidation of these functions has been hampered by the absence of selective IP receptor antagonists. Two structurally distinct series of IP receptor antagonists have been developed: 4,5-dihydro-1H-imidazol-2-yl)-[4-(4-isopropoxy-benzyl)-phenyl]-amine (RO1138452) and R-3-(4-fluoro-phenyl)-2-[5-(4-fluoro-phenyl)-benzofuran-2-ylmethoxycarbonylamino]-propionic acid (RO3244794).RO1138452 and RO3244794 display high affinity for IP receptors. In human platelets, the receptor affinities (pKi) were 9.3 +/- 0.1 and 7.7 +/- 0.03, respectively; in a recombinant IP receptor system, pKi values were 8.7 +/- 0.06 and 6.9 +/- 0.1, respectively. Functional antagonism of RO1138452 and RO3244794 was studied by measuring inhibition of carbaprostacyclin-induced cAMP accumulation in CHO-K1 cells stably expressing the human IP receptor. The antagonist affinities (pKi) of RO1138452 and RO3244794 were 9.0 +/- 0.06 and 8.5 +/- 0.11, respectively. Selectivity profiles for RO1138452 and RO3244794 were determined via a panel of receptor binding and enzyme assays. RO1138452 displayed affinity at I2 (8.3) and PAF (7.9) receptors, while RO3244794 was highly selective for the IP receptor: pKi values for EP1 (< 5), EP3 (5.38), EP4 (5.74) and TP (5.09). RO1138452 (1-10 mg kg(-1), i.v.) and RO3244794 (1-30 mg kg(-1), i.v.) significantly reduced acetic acid-induced abdominal constrictions. RO1138452 (3-100 mg kg(-1), p.o.) and RO3244794 (0.3-30 mg kg(-1), p.o.) significantly reduced carrageenan-induced mechanical hyperalgesia and edema formation. RO3244794 (1 and 10 mg kg(-1), p.o.) also significantly reduced chronic joint discomfort induced by monoiodoacetate. These data suggest that RO1138452 and RO3244794 are potent and selective antagonists for both human and rat IP receptors and that they possess analgesic and anti-inflammatory potential.

Animals↗
PubMed2005

IP-10 mediates selective mononuclear cell accumulation and activation in response to intrapulmonary transgenic expression and during adenovirus-induced pulmonary inflammation.

CXC chemokines that lack the glutamine-leucine-arginine (ELR) motif, including interferon (IFN)-inducible protein 10 (IP-10 or CXCL10), have been shown to mediate the generation of type 1 immune responses. In this study, we found that the intrapulmonary transient transgenic expression of murine IP-10 in mice using adenoviral gene transfer resulted in the early accumulation of neutrophils, natural killer (NK) cells, and NK T cells within the lung, followed by the delayed accumulation of CD4+ T cells. Adenovirus-mediated transgenic expression of IP-10 also resulted in selective activation of mononuclear cells, including gamma(delta)-T cells and NK cells, as manifest by CD69 expression or induction of cell-associated IFN-gamma. Importantly, the intratracheal (i.t.) administration of a control human type 5 adenovirus also caused significant accumulation of NK, NK T, and CD4+ T cells, which was maximal at 7 days post vector administration and was associated with the induction of IP-10. Neutralization of endogenous IP-10 in animals receiving control adenovirus resulted in decreases in the numbers of NK, CD4+, and CD8+ T cells. These results indicate that IP-10 can direct the accumulation and activation of neutrophils and selected mononuclear cells to the lung and that adenovirus-induced IP-10 contributes to lung inflammatory cell recruitment/activation observed in response to adenoviral vectors used for gene therapy.

Adenoviridae↗
PubMed1995

Glucose-dependent turnover of the mRNAs encoding succinate dehydrogenase peptides in Saccharomyces cerevisiae: sequence elements in the 5' untranslated region of the Ip mRNA play a dominant role.

We have demonstrated previously that glucose repression of mitochondrial biogenesis in Saccharomyces cerevisiae involves the control of the turnover of mRNAs for the iron protein (Ip) and flavoprotein (Fp) subunits of succinate dehydrogenase (SDH). Their half-lives are > 60 min in the presence of a nonfermentable carbon source (YPG medium) and < 5 min in glucose (YPD medium). This is a rare example in yeast in which the half-lives are > 60 min in the presence of a nonfermentable carbon source (YPG medium) and < 5 min in glucose (YPD medium). This is a rare example in yeast in which the half-life of an mRNA can be controlled by manipulating external conditions. In our current studies, a series of Ip transcripts with internal deletions as well as chimeric transcripts with heterologous sequences (internally or at the ends) have been examined, and we established that the 5'-untranslated region (5' UTR) of the Ip mRNA contains a major determinant controlling its differential turnover in YPG and YPD. Furthermore, the 5' exonuclease encoded by the XRN1 gene is required for the rapid degradation of the Ip and Fp mRNAs upon the addition of glucose. In the presence of cycloheximide the nucleolytic degradation of the Ip mRNA can be slowed down by stalled ribosomes to allow the identification of intermediates. Such intermediates have lost their 5' ends but still retain their 3' UTRs. If protein synthesis is inhibited at an early initiation step by the use of a prt1 mutation (affecting the initiation factor eIF3), the Ip and Fp mRNAs are very rapidly degraded even in YPG. Significantly, the arrest of translation by the introduction of a stable hairpin loop just upstream of the initiation codon does not alter the differential stability of the transcript in YPG and YPD. These observations suggest that a signaling pathway exists in which the external carbon source can control the turnover of mRNAs of specific mitochondrial proteins. Factors must be present that control either the activity or more likely the access of a nuclease to the select mRNAs. As a result, we propose that a competition between initiation of translation and nuclease action at the 5' end of the transcript determines the half-life of the Ip mRNA.

Base Sequence↗
PubMed1996

Interferon-gamma inducible protein (IP-10) expression is mediated by CD8+ T cells and is regulated by CD4+ T cells during the elicitation of contact hypersensitivity.

To investigate the potential roles of CD4+ and CD8+ T cells during contact hypersensitivity, we examined the T-cell-dependent expression of proinflammatory cytokine genes in the responses to dinitrofluorobenzene and oxazolone. Whole cell RNA was isolated from challenged ear tissue and analyzed for level of cytokine gene expression by Northern blot and densitometry analysis. Expression of interleukin 1 beta and the three chemokine genes (IP-10, JE, and KC) examined was dependent on the hapten dose used for sensitization and correlated with the immune response, i.e., ear swelling, elicited. Antibody-mediated depletion of CD8+ T cells before sensitization resulted in the absence of IP-10 expression following hapten challenge, indicating the ability of immune CD8+ T cells to mediate IP-10 expression. Depletion of CD4+ T cells resulted in higher levels of IP-10 and KC expression during elicitation of contact sensitivity, suggesting CD4+ T cells inhibit the expression of these proinflammatory genes. Depletion of CD4+ T cells resulted in contact hypersensitivity responses of higher magnitude and depletion of CD8+ T cells resulted in responses of lower magnitude. Transfer of CD8+ T-cell-depleted immune cells resulted in low, but detectable levels of IP-10 expression, indicating the ability of some oxazolone-immune CD4+ T cells to mediate IP-10 expression. These results indicate the differential induction of proinflammatory cytokine gene expression during elicitation of contact hypersensitivity in which expression of IP-10 is primarily mediated by immune CD8+ T cells and inhibited by immune CD4+ T cells.

Animals↗
PubMed2004

IP-10-encoding plasmid DNA therapy exhibits anti-tumor and anti-metastatic efficiency.

We report here that the interferon-induced protein of 10 kDa (IP-10 or CXCL10) elicits strong anti-tumor and anti-metastatic responses in mice when administered by plasmid DNA. Intratumoral but not intramuscular IP-10 DNA inoculation resulted in reduced tumor formation of malignant melanoma (B16F10) and Lewis lung carcinoma (LL/2) in C57BL/6 mice. In addition, plasmid DNA-encoding IP-10 substantially reduced the establishment of metastases when injected systemically by the intramuscular route. In contrast to the primary tumor model, the anti-metastatic effect of DNA-encoding IP-10 was primarily mediated by NK cells. Compared to DNA-encoding interleukin-12 (IL-12), therapy with DNA-encoding IP-10 exhibits lower efficacy against primary melanoma tumors but equivalent efficacy against primary Lewis lung tumors and against B16F10 lung metastasis formation. Co-administration of DNA-encoding IP-10 and IL-12 enhanced the anti-tumor activity of IL-12 in the lung metastasis model but had little effect in the local treatment of established subcutaneous tumors. Interestingly, treatment of nude mice lacking T lymphocytes with DNA-encoding IP-10 or IL-12 still resulted in a pronounced reduction of tumor growth or metastasis formation.

Animals↗
PubMed2002

Activation of p38 and ERK signaling during adenovirus vector cell entry lead to expression of the C-X-C chemokine IP-10.

The use of adenovirus vectors for human gene therapy is limited by potent inflammatory responses that result in significant morbidity. In kidney-derived epithelial cells (REC), activation of extracellular signal-regulated kinase 1/2 (ERK) and p38 kinase (p38) pathways occurred within 20 min of transduction with the serotype 5 adenovirus vector AdCMV beta gal. Inhibition of ERK and p38 with U0126 and SB203580, respectively, reduced the expression of IP-10 mRNA following transduction with AdCMV beta gal. To determine the role of the coxsackievirus-adenovirus receptor (CAR) or alpha(v) integrins in the activation of ERK and p38 and the expression of IP-10, REC cells were transduced with the fiber-modified and RGD-deleted adenovirus vectors AdL.F(RAEK-HA) and AdL.PB(HA), respectively. Compared with the wild-type capsid vector Ad5Luc, transduction with AdL.F(RAEK-HA) and AdL.PB(HA) resulted in reduced ERK-p38 activation and less IP-10 mRNA expression. The decreased IP-10 expression induced by the tropism-modified vectors was due to diminished transduction, since increasing multiplicity of infection resulted in increased IP-10 expression. Inhibition of adenovirus penetration with bafilomycin A1 or ammonium chloride attenuated the activation of ERK-p38 and IP-10 mRNA expression following infection, suggesting that endosomal escape was required to trigger these pathways. In vivo, direct inhibition of ERK and p38 signaling pathways inhibited adenovirus vector-induced IP-10 expression in mouse liver 1 h following transduction. These results demonstrate the importance of signaling via ERK and p38 in the early host response to adenovirus vectors and will permit the development of novel strategies to improve the safety and efficacy of these agents in human gene therapy.

Adenovirus Infections, Human↗
PubMed2000

Multiple receptor activation elicits synergistic IP formation in nonpigmented ciliary body epithelial cells.

We have examined the interaction between muscarinic and alpha(2)-adrenergic receptor activation on inositol phosphate (IP) formation in the nonpigmented cells of the ciliary body epithelium (NPE cells) of the rabbit. We have compared these changes with those previously observed in the intracellular free Ca(2+) concentration. Whereas muscarinic receptor activation causes an increase in intracellular Ca(2+) and IP formation, activation of alpha(2)-receptors does not significantly increase either intracellular Ca(2+) or IPs over basal levels. However, simultaneous activation of muscarinic and alpha(2)-adrenergic receptors with the specific agonists carbachol and UK-14304 produces massive Ca(2+) increases and results in a synergistic increase in IP formation. This synergistic IP formation is inhibited by both muscarinic and alpha(2)-adrenergic receptor antagonists as well as by pertussis toxin and an inhibitor of phospholipase C. IP formation is predominantly independent of intracellular Ca(2+), because it is decreased but not prevented by blocking the entry of Ca(2+) with LaCl(3) or chelating intracellular Ca(2+) with 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Thus synergistic IP formation underlies, at least in part, the synergistic increase in intracellular Ca(2+) resulting from simultaneous activation of muscarinic and alpha(2)-adrenergic receptors.

Adrenergic alpha-Agonists↗
PubMed2002

Coexistence of functional IP(3) and ryanodine receptors in vagal sensory neurons and their activation by ATP.

Intracellular photorelease of caged D-myo-inositol 1,4,5-trisphosphate (IP(3)), caffeine application, and immunofluorescence confocal microscopy were used to determine that D-myo-inositol 1,4,5-trisphosphate receptors (IP(3)Rs) and ryanodine receptors (RyRs) coexist in rabbit vagal sensory nodose ganglion neurons (NGNs). ATP, an extracellular physiological signaling molecule, consistently evoked robust transient increases in cytosolic free Ca(2+) concentration (Ca(2+) transients). ATP applied in Ca(2+)-free physiological saline elicited Ca(2+) transients that averaged approximately 70% of the amplitude of transients evoked in the presence of extracellular Ca(2+). The component of the ATP-evoked Ca(2+) transient that was independent of extracellular Ca(2+) corresponds to Ca(2+) release from intracellular stores. This release component was sensitive to the pharmacological antagonists pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), U73122, neomycin, and heparin (13.5-15 kD), indicating that P2 purinoreceptors (P2Y) and the IP(3) signaling pathway are required for ATP-evoked Ca(2+) release. Additionally, a portion of ATP-evoked Ca(2+) release was inhibited by ryanodine, a selective blocker of RyRs. The ryanodine-insensitive component (approximately 70%) of ATP-evoked Ca(2+) release corresponds to IP(3)-induced Ca(2+) release via IP(3)Rs, while the ryanodine-sensitive component (approximately 30%) corresponds to consequent Ca(2+)-induced Ca(2+) release (CICR) via RyRs. These results indicate that functional IP(3)Rs and RyRs coexist in nodose neurons and that both IP(3)-induced Ca(2+) release and CICR can be activated by ATP.

Adenosine Triphosphate↗
PubMedDate not supplied

Cell-specific expression of the IP(3) receptor gene family in the kidney.

BACKGROUND/AIM: The localization of inositol trisphosphate (IP(3)) receptor isoforms, types 1-3, in the kidney and their role in the regulation of the intracellular calcium concentration - [Ca(2+)](i) - are discussed. METHODS: Immunohistological studies with isoform-specific antibodies were performed to reveal the localization of IP(3) receptor isoforms. To examine the role of IP(3) receptor type 1 in the glomeruli, the responses of [Ca(2+)](i) to hormonal stimuli were examined in IP(3) receptor type 1 knockout mice. RESULTS: In the immunohistological study, type 1 receptor was present in arteries, afferent arterioles, and mesangial cells. Double staining with antibodies against aquaporin 2 and IP(3) type 2 receptor revealed that type 2 receptor was localized mainly in the intercalated cells. The type 3 receptor showed characteristic intracellular localization in the collecting duct cells of the cortex to the outer medulla. Immunostaining of type 3 receptor was most intense in the cytoplasm on the basolateral membrane side and was not seen on the apical side. The responses of [Ca(2+)](i) to angiotensin II and endothelin in the glomeruli were markedly attenuated in IP(3) receptor type 1 knockout mice. CONCLUSIONS: The three isoforms of the IP(3) receptor showed distinctive localization in the kidney, and the type 1 receptor plays a major role in the regulation of [Ca(2+)](i) in the glomeruli. The physiological significance of the cell-specific localization, however, remains to be determined.

Animals↗
PubMed2006

Expression of IP-10/CXCL10 is upregulated by double-stranded RNA in BEAS-2B bronchial epithelial cells.

BACKGROUND: Interferon (IFN)-gamma-inducible protein of 10 kDa (IP-10/CXCL10) is a potent chemoattractant for activated T and NK cells, and elevated levels of IP-10 are identified in bronchoalveolar lavage fluids from patients with pulmonary disorders related to Th-1-type immunity, which is a prerequisite for elimination of viral pathogens. Bronchial epithelial cells play an important role in respiratory infections as the initiator of airway inflammation by releasing chemokines and expressing cell surface membrane molecules involved in leukocyte adhesion. Polyinosinic-polycytidylic acid (poly IC) is a synthetic double-stranded RNA (dsRNA) and induces antiviral reactions in cells. OBJECTIVES: We investigated the regulation of IP-10 in BEAS-2B bronchial epithelial cells in response to poly IC, and also addressed the possible role of retinoic-acid-inducible gene-I (RIG-I) and IFN-regulatory factor 3 (IRF-3), two genes involved in the signaling induced by viral infection. METHODS: The expressions of IP-10 mRNA and protein were analyzed by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. The overexpression of RIG-I or IRF-3 was performed by transfection of BEAS-2B cells with each cDNA. RESULTS: Poly IC enhanced the expression of IP-10 mRNA and protein in concentration- and time-dependent manners. Overexpression of RIG-I or IRF-3 potentiated the poly-IC-induced upregulation of IP-10. CONCLUSIONS: IP-10 may contribute to antiviral activity through the activation of Th-1-type immunity, and RIG-I and IRF-3 may be involved in this reaction.

Bronchi↗
PubMed2006

TLR agonists induce regulatory dendritic cells to recruit Th1 cells via preferential IP-10 secretion and inhibit Th1 proliferation.

Dendritic cells (DCs) and chemokines are important mediators linking innate and adaptive immunity on activation by Toll-like receptor (TLR) agonists. We previously identified a kind of regulatory DC subset (diffDCs) that differentiated from mature DCs under splenic stroma and that inhibited T-cell proliferation. The responsiveness of such regulatory DCs to TLR agonists and their pattern of chemokine production remain to be determined. Here, we report that the regulatory DCs secrete a higher level of CXCR3 chemokine IFN-gamma-induced protein-10 (IP-10) than immature DCs (imDCs), and more IP-10 is produced after stimulation with TLR-2, -4, -3, and -9 ligands. Blockade of IFN-alpha/beta inhibits IP-10 production by TLR agonist-activated regulatory DCs. We show that the increased IRF-3 and IFN-beta-induced STAT1 activation are responsible for the autocrine IFN-beta-dependent preferential production of IP-10 by regulatory DCs. In addition, stimulation with recombinant mouse IFN-alpha/beta induces more IP-10 production in regulatory DCs than that in imDCs. Moreover, the regulatory DCs selectively recruit more Th1 cells through IP-10 and inhibit Th1 proliferation. Our results demonstrate a new manner for regulatory DCs to down-regulate T-cell response by preferential IP-10 production and inhibition of recruited Th1 cell proliferation.

Animals↗