Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vasoactive intestinal peptide (VIP) expression is restricted to interneurons in the hippocampus of normal adult rats. However, 3-6 hours after a 60-minute walk in an activity wheel, VIP was transiently expressed in most pyramidal and granular neurons of the hippocampus. Locomotion was also associated with a dramatic increase in VIP immunoreactivity in the motor cortex, primarily in bipolar cells. Reverse transcriptase-polymerase chain reaction analysis indicated that VIP mRNA increases transiently by more than twofold, before the increases in peptide immunoreactivity in both the hippocampus and motor cortex. By comparison, another marker of inhibitory interneurons, glutamate decarboxylase, did not change its expression pattern after locomotion. The calcium binding protein, calbindin-D28K, normally expressed in interneurons, was now found also in glial cells of the hippocampus and motor cortex. Another marker of enhanced electrical activity, the immediate early gene, c-Fos, was expressed in pyramidal and granular neurons at 3 hours but not at 6 hours after locomotion. These results suggest that mapping of peptide expression in the brain of a docile, inactive rat may not reflect the real distribution and functions of a peptide in an active animal.
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PMID:Locomotor activity causes a rapid up-regulation of vasoactive intestinal peptide in the rat hippocampus. 1056 Sep 24

To unravel the molecular regulation of renal transcellular Ca(2+) transport, a murine distal convoluted tubule (mpkDCT) cell line derived from distal convoluted tubules (DCT) microdissected from a SV-PK/Tag transgenic mouse was characterized. This cell line originated from DCT only, as mRNA encoding for the DCT marker thiazide-sensitive Na(+)/Cl(-) cotransporter was expressed, whereas mRNA encoding for the connecting tubule and collecting duct marker aquaporin-2 was not detected, as determined by reverse-transcriptase PCR. mpkDCT cells expressed mRNA encoding the Ca(2+) channels TRPV5 and TRPV6 and other key players necessary for transcellular Ca(2+) transport, i.e., calbindin-D(9k), calbindin-D(28k), plasma membrane Ca(2+)-ATPase isoform 1b, and Na(+)/Ca(2+) exchanger 1. Primary cultures of DCT cells exhibited net transcellular Ca(2+) transport of 0.4 +/- 0.1 nmol.h(-1).cm(-2), whereas net transcellular Ca(2+) transport across mpkDCT cells was significantly higher at 2.4 +/- 0.4 nmol.h(-1).cm(-2). Transcellular Ca(2+) transport across mpkDCT cells was completely inhibited by ruthenium red, an inhibitor of TRPV5 and TRPV6, but not by the voltage-operated Ca(2+) channel inhibitors felodipine and verapamil. With the use of patch-clamp analysis, the IC(50) of ruthenium red on Na(+) currents was between the values measured for TRPV5- and TRPV6-expressing HEK 293 cells, suggesting that TRPV5 and/or TRPV6 is possibly active in mpkDCT cells. Forskolin in combination with IBMX, 1,25-dihydroxyvitamin D(3), and 1-deamino-8-d-arginine vasopressin increased transcellular Ca(2+) transport, whereas PMA and parathyroid hormone had no significant effect. In conclusion, the murine mpkDCT cell line provides a unique cell model in which to study the molecular regulation of transcellular Ca(2+) transport in the kidney in vitro.
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PMID:Characterization of a murine renal distal convoluted tubule cell line for the study of transcellular calcium transport. 1462 1

Stroking the mucosal lining of the guinea pig colon with a brush elicits an intestinal neural reflex, and an increase in short-circuit current (Isc) indicative of chloride secretion. We tested whether endogenous and exogenous nucleotides are physiologic regulators of mucosal reflexes that modulate chloride secretion. The basal Isc was augmented by 6-N,N-diethyl-beta,gamma-dibromomethylene-D-adenosine-5'-triphosphate (ARL67156) inhibition of nucleotide breakdown or adenosine A1 receptor blockade and reduced by apyrase inactivation of nucleotidases, P2 receptor antagonists, tetrodotoxin (TTX), or piroxicam. ARL67156 augmented, and apyrase inhibited, stroking-evoked Isc responses. TTX and atropine inhibited nucleotide-evoked Isc responses. The agonist potency profile for Isc, 2-methylthioadenosine-diphosphate (2MeSADP) = 2-methioadenosine-triphosphate >> 5'adenosine-triphosphate (ATP) > or = 5'adenosine-diphosphate > 5'uridine-triphosphate > or = 5'uridine-diphosphate, supports a P2Y1 receptor (R). The P2 receptor antagonists suramin and pyridoxalphosphate-6-azophenyl-2'4'-disulfonic acid, reduced stroking responses (36%) and their effects were additive. The selective P2Y1 R antagonist, 2'deoxy-N6-methyl adenosine 3',5'-diphosphate diammonium salt, reduced stroking (54%) and 2MeSADP (70%) responses at P2Y1 Rs. The P2X1/3 R agonist, alpha,betaMeATP, increased Isc. A desensitizing dose of alpha,betaMeATP reduced stroking Isc responses but did not prevent the 2MeSADP-evoked Isc response. Reverse transcriptase polymerase chain reaction analysis revealed mRNAs for P2Y1 R, P2Y2 R, P2Y4 R, P2Y6 R, and P2Y12 R in submucosa. The expression of P2Y R immunoreactivity (ir) in cell bodies of submucous neurons followed the order of P2Y1 = P2Y2 >> P2Y4 R ir; P2Y1 Rs and P2Y2 R ir were abundant (21-50% of neurons). P2Y1 R ir was abundant in cholinergic secretomotor neurons and fewer than 2% of neuropeptide Y (NPY)/choline acetyltransferase secretomotor neurons, and P2Y2 R ir was expressed in virtually all NPY secretomotor neurons and approximately 30% of calbindin/intrinsic primary afferent neurons. P2Y4 R ir was present in NPY-positive neurons. P2Y ir was rare or absent in varicose nerve fibers. The functional data support the hypothesis that mechanical stimulation with a brush releases nucleotides that act predominantly at P2Y1 Rs and to a lesser extent on P2X1/3 Rs to mediate reflex chloride secretion. A separate P2Y2 R neural circuit pathway exists that is not activated by mechanical forces. Other receptors including P2Y4, P2Y6, P2Y12, or P4 Rs cannot be excluded.
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PMID:Mechanical stimulation releases nucleotides that activate P2Y1 receptors to trigger neural reflex chloride secretion in guinea pig distal colon. 1468 70

Mechanical activation of the mucosal lining of the colon by brush stroking elicits an intestinal neural reflex and an increase in short circuit current (Isc) indicative of electrogenic chloride ion transport. We tested whether endogenous nucleotides are physiologic regulators of mucosal reflexes that control ion transport. The brush stroking-evoked Isc response in mucosa and submucosa preparations (M-SMP) of rat colon was reduced by the P2Y1 receptor (R) antagonist 2'deoxy-N6-methyl adenosine 3',5'-diphosphate diammonium salt (MRS 2179) and further blocked by tetrodotoxin (TTX). M-SMP Isc responses to serosal application of the P2Y1 R agonist 2-methylthioadenosine-diphosphate (2MeSADP) or the P2Y2/P2Y4 R agonist 5'uridine-triphosphate (UTP) were reduced but not abolished by TTX. The potency profile of nucleotides for increasing Isc was 5'adenosine-triphosphate (ATP; effective concentration at half maximal response [EC50] 0.65 x 10(4) M) congruent with UTP (EC50 1.0 x 10(-4) M) congruent with 2MeSADP (EC50 = 1.60 x 10(-4) M). Mucosal touch and distention-induced Ca2+ transients in submucous neurons were reduced by apyrase and prevented by blocking the P2Y1 R with MRS 2179 and TTX; denervation of the mucosa. It did not occur by touching a ganglion directly. 2MeSADP Ca2+ responses occurred in subsets of neurons with or without substance P (SP) responses. The potency profile of nucleotides on the neural Ca2+ response was 2MeSADP (5 x 10(-7) M) > UTP (6 x 10(-6) M) > ATP (9 x 10(-5) M). The expression of P2Y R immunoreactivity (ir) in nerve cell bodies was in the order of P2Y1 R > P2Y4 R >> P2Y2 R. P2Y1R ir occurred in the cell somas of more than 90% of neuronal nitric oxide synthase, vasoactive intestinal peptide (VIP), calretinin, or neuropeptide Y (NPY)-ir neurons, 78% of somatostatin neurons, but not in calbindin or SP neurons. P2Y2 R ir was expressed in a minority of SP, VIP, NPY, vesicular acetylcholine transporter, and calcitonin gene-related peptide-ir varicose fibers (5-20%) and those surrounding calbindin (5-20%) neurons. P2Y4 ir occurred mainly in the cell somas of 93% of NPY neurons. Reverse transcriptase polymerase chain reaction of the submucosa demonstrated mRNA for P2Y1R, P2Y2, P2Y4, P2Y6, and P2Y12 Rs. Expression of P2Y1, P2Y2, and P2Y4 protein was confirmed by western blots. In conclusion, endogenous nucleotides acting at P2YRs transduce mechanically evoked reflex chloride ion transport in rat distal colon. Nucleotides evoke reflexes by acting primarily at postsynaptic P2Y1 Rs and P2Y4 R on VIP+/NPY+ secretomotor neurons, at P2Y2 Rs on no more than 2% of VIP+ secretomotor neurons, and 2Y2 Rs mainly of extrinsic varicose fibers surrounding putative intrinsic primary afferent and secretomotor neurons. During mucosal mechanical reflexes, it is postulated that P2Y1 R, P2Y2 R, and P2Y4 R are activated by endogenous ATP, UTP, and 5'uridine-diphosphate.
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PMID:Mechanically evoked reflex electrogenic chloride secretion in rat distal colon is triggered by endogenous nucleotides acting at P2Y1, P2Y2, and P2Y4 receptors. 1468 71

We investigated the expression and functions of chemokine receptors in neural progenitor cells isolated from embryonic and adult mice. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis demonstrated mRNA expression for most known chemokine receptors in neural progenitor cells grown as neurospheres from embryonic (E17) and adult (4-week-old) mice. The expression of CXCR4 receptors was demonstrated further in E17 neurospheres using immunohistochemistry, in situ hybridization, Northern blot analysis and fura-2-based Ca(2+) imaging. Most neurospheres grown from E17 mice responded to stromal cell-derived factor-1 (SDF-1/CXCL12) in Ca(2+) imaging studies. In addition, immunohistochemical studies demonstrated that these neurospheres consisted of dividing cells that uniformly colocalized nestin and CXCR4 receptors. Differentiation of E17 neurospheres yielded astrocytes and neurons exhibiting several different phenotypes, including expression of calbindin, calretinin, gamma-aminobutyric acid (GABA), and glutamate, and many also coexpressed CXCR4 receptors. In addition, neurospheres grown from the subventricular zone (SVZ) of 4-week-old mice exhibited large increases in Ca(2+) in response to CXCL12 and several other chemokines. In comparison, neurospheres prepared from olfactory bulb of adult mice exhibited only small Ca(2+) responses to CXCL12, whereas neurospheres prepared from hippocampus were insensitive to CXCL12, although they did respond to other chemokines. Investigations designed to investigate whether CXCL12 can act as a chemoattractant demonstrated that cells dissociated from E17 or adult SVZ neurospheres migrated toward an CXCL12 gradient and this was blocked by the CXCR4 antagonist AMD3100. These results illustrate widespread chemokine sensitivity of embryonic and adult neural progenitor cells and support the view that chemokines may be of general importance in control of progenitor cell migration in embryonic and adult brain.
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PMID:Chemokine receptors are expressed widely by embryonic and adult neural progenitor cells. 1504 27

Transient receptor potential channel vanilloid subfamily 2 (TRPV2) was shown to receive noxious thermal stimuli (>52 degrees C), and to be expressed in fine myelinated afferent neurons. The mRNA and the immunoreactivity have also been detected in several peripheral tissues. We examined the expression of TRPV2 in the rat intestine. An analysis by transcriptase-polymerase chain reaction (RT-PCR) demonstrated TRPV2 gene expression in the intestine. Many TRPV2-positive neurons were observed in the myenteric plexus by immunohistochemistry. Some of these neurons were positive for calbindin D-28K (CaBP), which is present in intrinsic afferent neurons. TRPV2 immunoreactivity was also observed in nodose ganglion neurons (vagal afferents). These findings suggest that TRPV2 is expressed not only in sensory ganglion neurons, but also in enteric neurons, including primary afferent neurons.
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PMID:TRPV2-immunoreactive intrinsic neurons in the rat intestine. 1527 45

Diabetes is associated with renal calcium and magnesium wasting, but the molecular mechanisms of these defects are unknown. We measured renal calcium and magnesium handling and investigated the effects of diabetes on calcium and magnesium transporters in the thick ascending limb and distal convoluted tubule in streptozotocin (STZ)-induced diabetic rats. Rats were killed 2 weeks after inducing diabetes, gene expression of calcium and magnesium transporters in the kidney was determined by real-time polymerase chain reaction, and the abundance of protein was assessed by immunoblotting. Our results showed that diabetic rats had significant increase in the fractional excretion for calcium and magnesium (both P < 0.01), but not for sodium. Reverse transcriptase-polymerase chain reaction revealed significant increases in messenger RNA abundance of transient potential receptor (TRP) V5 (223 +/- 10%), TRPV6 (177 +/- 9%), calbindin-D28k (231 +/- 8%), and TRPM6 (165 +/- 8%) in diabetic rats. Sodium chloride cotransporter was also increased (207 +/- 10%). No change was found in paracellin-1 (cortex: 108 +/- 8%; medulla: 110 +/- 10%). Immunofluorescent studies of renal sections showed significant increase in calbindin-D28k (238 +/- 10%) and TRPV5 (211 +/- 10%), but no changes in paracellin-1 in Western blotting (cortex: 110 +/- 7%; medulla: 99 +/- 7%). Insulin administration completely corrected the hyperglycemia-associated hypercalciuria and hypermagnesiuria, and reversed the increase of calcium and magnesium transporter abundance. In conclusion, our results demonstrated increased renal calcium and magnesium transporter abundance in STZ-induced diabetic rats, which may represent a compensatory adaptation for the increased load of calcium and magnesium to the distal tubule.
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PMID:Increased renal calcium and magnesium transporter abundance in streptozotocin-induced diabetes mellitus. 1655 23

Reverse transcriptase (RT) inhibitors are emerging as a novel class of anticancer differentiating agents, active in several human tumor cell models, such as melanoma and prostate, thyroid and colon carcinoma. Indeed, much evidence suggests that they may act by inhibiting endogenous RT, a gene highly expressed in undifferentiated and transformed cells. We therefore evaluated whether endogenous RT may represent a new molecular target in the treatment of human renal clear-cell carcinoma, a neoplasm with very low sensitivity to standard pharmacological therapies. Efavirenz and nevirapine, 2 non-nucleosidic RT inhibitors commonly used in HIV patients, either induced a reversible downregulation of cell proliferation or enhanced cell differentiation in primary cultures of human renal carcinoma cells characterized by high levels of endogenous RT activity. Both agents upregulated the expression of the vitamin D receptor and calbindin 28k genes, which are constitutively expressed in renal tubular cells, and induced vitamin D signaling by enhancing the ability of tumor cells to upregulate the vitamin D-dependent gene, CYP24. Furthermore, efavirenz- and nevirapine-differentiated tumor cells exhibited an immunogenic phenotype with an increased expression of HLA-I and CD40 antigens and an enhanced ability to elicit a specific T-cell response in mixed lymphocyte/tumor-cell cultures. Indeed, renal carcinoma cells exposed to efavirenz induced a CD8(+)CCR7-CD45RA(-) effector memory T-cell phenotype, whereas untreated RCC cells induced a CD8(+)CCR7(+)CD45RA(-) central memory T-cell phenotype. These data suggest that RT inhibitors may be a novel tool in the treatment of human renal clear-cell carcinoma, potentially able to enhance the immunogenic potential of tumor cell.
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PMID:Reverse transcriptase inhibitors induce cell differentiation and enhance the immunogenic phenotype in human renal clear-cell carcinoma. 1835 78

The canonical transient receptor potential (TRPC) family of ion channels is implicated in many neuronal processes including calcium homeostasis, membrane excitability, synaptic transmission, and axon guidance. TRPC channels are postulated to be important in the functional neurobiology of the enteric nervous system (ENS); nevertheless, details for expression in the ENS are lacking. Reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry were used to study the expression and localization of TRPC channels. We found mRNA transcripts, protein on Western blots, and immunoreactivity (IR) for TRPC1/3/4/6 expressed in the small intestinal ENS of adult guinea pigs. TRPC1/3/4/6-IR was localized to distinct subpopulations of enteric neurons and was differentially distributed between the myenteric and submucosal divisions of the ENS. TRPC1-IR was widely distributed and localized to neurons with cholinergic, calretinin, and nitrergic neuronal immunochemical codes in the myenteric plexus. It was localized to both cholinergic and noncholinergic secretomotor neurons in the submucosal plexus. TRPC3-IR was found only in the submucosal plexus and was expressed exclusively by neuropeptide Y-IR neurons. TRPC4/6-IR was expressed in only a small population of myenteric neurons, but was abundantly expressed in the submucosal plexus. TRPC4/6-IR was coexpressed with both cholinergic and nitrergic neurochemical codes in the myenteric plexus. In the submucosal plexus, TRPC4/6-IR was expressed exclusively in noncholinergic secretomotor neurons. No TRPC1/3/4/6-IR was found in calbindin-IR neurons. TRPC3/4/6-IR was widely expressed along varicose nerve fibers and colocalized with synaptophysin-IR at putative neurotransmitter release sites. Our results suggest important roles for TRPC channels in ENS physiology and neuronal regulation of gut function.
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PMID:Differential expression of canonical (classical) transient receptor potential channels in guinea pig enteric nervous system. 1892 32