Expression and Clinical Values of Serum miR-155 and miR-224 in Chinese Patients with HCV Infection.

BACKGROUND: To investigate the expression of serum miR-155 and miR-224 among patients with hepatitis C virus (HCV) infection and analyze their clinical values. METHODS: A total of 116 patients suffering from HCV infection admitted to our hospital and 70 healthy subjects were selected. According to the diagnostic results, patients with HCV infection were divided into 48 cases of chronic hepatitis C (CHC), 43 cases of liver cirrhosis and 25 cases of hepatocellular carcinoma (HCC). The expression signature for miR-155 and miR-224 was detected in serum samples. ROC curve and Pearson correlation test were conducted to investigate their diagnostic value and correlation. RESULTS: The expression extent for serum miR-155 and miR-224 increased along with the increase of malignancy (all P < 0.05). According to ROC curve, the area under the curve (0.918, 95% CI: 0.856-0.974) of miR-155 and miR-224 combined in the diagnosis of HCC was the largest, and its sensitivity and specificity were 93.0% and 86.2%. There is a positive relationship for expression level between miR-155 and miR-224 in CHC and HCC group (all P < 0.001). CONCLUSION: miR-155 and miR-224 are remarkably increased in patients suffering from HCV infection. The combination of miR-155 and miR-224 has a good diagnostic value for HCC caused by HCV infection.

MicroRNA-19a mediates neuroprotection through the PTEN/AKT pathway in SK-N-SH cells after oxygen-glucose deprivation/reoxygenation injury.

Ischemic stroke is one of the most common public health problems worldwide. The aim of the present study was to investigate the role of miR-19a and its possible target genes in SK-N-SH cells subjected to oxygen-glucose deprivation/re-oxygenation (OGD/R) injury. SK-N-SH cells are a suitable model for host transfection. SK-N-SH cells were transfected with miR-19a mimic or inhibitor and PTEN-small interfering (si) RNA in order to alter the expression of miR-19a, PTEN and AKT. The expression changes in acute cerebral ischemic injury (ACII) were verified using RT-qPCR and Western blotting. Expression changes and the association between miR-19a and PTEN following OGD/R were also assessed using a double luciferase analysis. In addition, cell viability and apoptosis were measured using an MTT and flow cytometry. miR-19a was downregulated; however, PTEN was markedly increased following OGD/R injury. miR-19a mimics increased cell viability, decreased cell apoptosis of SK-N-SH cells following OGD/R, which effects was similar to PTEN siRNA; however, miR-19a inhibitor had the opposite roles with miR-19a mimics. The present study provides novel information about the cell apoptosis and invasion mechanisms associated with the miR-19a/PTEN/AKT pathway and may present a potential therapeutic approach for OGD/R injury.

Association between TLR2 Arg677Trp polymorphism and tuberculosis susceptibility: A meta-analysis.

BACKGROUND: Toll-like receptor 2 (TLR2) is an important member of TLRs, which is significant in the initial of inflammatory response against bacteria. Several studies have been conducted to investigate the TLR2 Arg677Trp polymorphism and Tuberculosis (TB) susceptibility. Unfortunately, the results of previous studies were inconsistent. OBJECTIVES: The aim of present study was to investigate the relationship between TLR2 Arg677Trp polymorphisms and TB susceptibility. METHODS: The association between the TLR2 Arg677Trp polymorphism and TB susceptibility was assessed by odds ratios (OR) together with their 95% confidence intervals (95%CI). RESULTS: Six case-control studies were enrolled in the meta-analysis. Overall, significant association between TLR2 Arg677Trp polymorphism and TB risk were found neither under allele contrast (C vs. T: OR = 0.59, 95%CI = 0.28-1.23, P = 0.158) nor under recessive genetic model (CC vs. CT/TT: OR = 0.43, 95%CI = 0.12-1.51, P = 0.188). CONCLUSION: We conclude that TLR2 Arg677Trp polymorphism is not associated with TB susceptibility.

Association between the IL-10 and IL-6 polymorphisms and brucellosis susceptibility: a meta-analysis.

BACKGROUND: Brucellosis is a quite normal zoonotic infection, which is caused by immediate contact with animals infected with Brucella or its products. IL-10 (- 1082 G/A, - 819 C/T, - 592C/A) and IL-6 -174 G/C polymorphisms have a great relationship with IL-10 and IL-6 production, which brings about Brucellosis pathogenesis and development. So far, the results of published literatures were controversial. Now, we perform a meta-analysis in different ethnic populations to get a more precise estimate of above polymorphisms with Brucellosis susceptibility. METHODS: Both OR and corresponding 95%CI were enrolled to make an assessment of the association strength through extracting genotyping frequency of cases and controls. The χ2-test based Q-statistic and I2 statistics were applied. If there was no evident heterogeneity, the fixed-effects model would be applied. If not, the random-effects model would be used. RESULTS: The significant associations were only found in Asian population of - 819 loci under three genetic models as follows: (Allele model: OR = 0.60, 95%CI = 0.44-0.82, P = 0.001), (homozygote comparison: OR = 0.24, 95%CI = 0.09-0.62, P = 0.003), (recessive genetic model: OR = 0.22, 95%CI = 0.05-0.91, P = 0.036). CONCLUSION: In conclusion, IL-10 - 819 loci polymorphism contributes no risk to Caucasian population but may be associated with decreased risk in Asian population. And IL-10 -1082 G/A, 592 loci and IL-6 -174 G/C polymorphism are not associated with Brucellosis risk.

Association between the IL-10-1082G/A, IL-10-819T/C and IL-10-592A/C polymorphisms and Brucellosis susceptibility: a meta-analysis.

Brucellosis is a widespread zoonosis caused by small bacteria of the genus Brucella. The promoter polymorphisms of IL-10 (-1082 loci, -819 loci and -590 loci) are closely related to the production of IL-10, leading to the alteration of development and pathogenesis of Brucellosis. However, the previous results were controversial. In the present study, we conduct the meta-analysis to get a more precise result of IL-10 polymorphisms with Brucellosis risk. The quality of the studies was assessed according to a predefined scale. The odds ratio (OR) and 95% confidence interval (CI) were counted to evaluate the association strength. No significant association was found between position -1082 loci or -590 loci polymorphism and Brucellosis risk. The significant association was found in Asian population of position -819 (T vs. C: OR 0.60, 95% CI 0.44-0.82, P = 0.001), homozygote comparison (TT vs. CC: OR 0.24, 95% CI 0.09-0.62, P = 0.003) and recessive genetic model (TT vs. TC/CC: OR 0.22, 95% CI 0.05-0.91, P = 0.036). The present meta-analysis demonstrates that IL-10-819 loci polymorphism is not associated with Brucellosis risk of Caucasian population but may contribute a decreased risk to Asian population. And neither IL-10-1082 loci nor -592 loci polymorphism is associated with Brucellosis risk.

Quantitative assessment of the association between IL-10 -592 A/C polymorphism and Kawasaki disease risk in Chinese population: evidence from a meta-analysis.

BACKGROUND: IL-10, as a proinflammatory and anti-inflammatory cytokine, has been thought to have an important role in the development of Kawasaki disease. Variation in the IL-10 gene might lead to altered protein production, which may result in Kawasaki disease. Several studies have been performed to investigate the IL-10 -592 A/C polymorphism and Kawasaki disease risk. Unfortunately, the results of previous studies were inconsistent. Therefore, we performed a meta-analysis to derive a more precise estimation of the association between the IL-10 -592 A/C polymorphism and Kawasaki disease risk. METHOD: The association between the IL-10 -592 A/C polymorphism and Kawasaki disease risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs). Six studies were enrolled in the present meta-analysis. RESULTS: Overall, no significant association between IL-10 -592 A/C polymorphism and Kawasaki disease risk was found under allele contrast (A versus C: OR=0.95, 95% CI=0.77-1.18, p=0.668), homozygote comparison (AA versus CC: OR=0.86, 95% CI=0.56-1.31, p=0.475), heterozygote comparison (CA versus CC: OR=0.88, 95% CI=0.65-1.19, p=0.479), recessive genetic model (AA versus CA/CC: OR=0.96, 95% CI=0.73-1.28, p=0.801), or dominant genetic model (AA/CA versus CC: OR=0.85, 95% CI=0.64-1.13, p=0.275). CONCLUSIONS: We conclude that IL-10 -592 A/C polymorphism was not associated with Kawasaki disease risk in the Chinese population. However, more primary large-scale and well-designed studies are still required to further evaluate the interaction of IL-10 -592 A/C polymorphism with Kawasaki disease risk.

Association between TLR2 + 2477G/A polymorphism and bacterial meningitis: a meta-analysis.

Toll-like receptor 2 (TLR2) is a key member of TLRs, which is crucial in the initial inflammatory response against bacteria. TLR2, is also the initial barrier against bacterial infection and plays an important role in recognising a variety of bacterial lipoproteins. Several studies have been performed to investigate the TLR2 + 2477G/A polymorphism and bacterial meningitis susceptibility. Unfortunately, the results of previous studies were controversial. Therefore, we performed a meta-analysis to derive a more precise estimation of the association. The association between the TLR2 + 2477G/A polymorphism and bacterial meningitis susceptibility was assessed by odds ratios together with their 95% confidence intervals (CI). Six studies were enrolled in the present meta-analysis. Overall, no significant association between TLR2 + 2477G/A polymorphism and bacterial meningitis risk were found under allele contrast (A vs. G: OR = 1.15, 95% CI = 0.93-1.43, P = 0.202), recessive genetic model (AA vs. AG/GG: OR = 1.12, 95% CI = 0.90-1.41, P = 0.313). The significant association was found between TLR2 + 2477G/A polymorphism and pneumococcal meningitis risk under allele contrast (A vs. G: OR = 1.54, 95% CI = 1.01-2.36, P = 0.046), recessive genetic model (AA vs. AG/GG: OR = 1.63, 95% CI = 1.03-2.57, P = 0.035). We conclude that TLR2 + 2477G/A polymorphism is not associated with meningococcal meningitis risk but contributes an increased risk of pneumococcal meningitis.

Determination of the Residues in the Extracellular Domain of the Nicotinic α Subunit Required for the Actions of Physostigmine on Neuronal Nicotinic Receptors.

Physostigmine can potentiate and inhibit neuronal nicotinic receptors, in addition to inhibiting the activity of acetylcholinesterase. We found that receptors containing three copies of the α2 subunit are inhibited by low concentrations of physostigmine in contrast to receptors containing three copies of the α4 subunit that are potentiated. We exploited this observation to determine the regions required for the actions of physostigmine. Chimeric constructs of the α2 and α4 subunits located two regions in the extracellular amino-terminal domain of the subunit: the E loop (a loop of the transmitter-binding domain) and a region closer to the amino-terminus that collectively could completely determine the different effects of physostigmine. Point mutations then identified a single residue, α2(I92) versus α4(R92), that, when combined with transfer of the E loop, could convert the inhibition seen with α2 subunits to potentiation and the potentiation seen with α4 subunits to inhibition. In addition, other point mutations could affect the extent of potentiation or inhibition, indicating that a more extensive set of interactions in the amino-terminal domain plays some role in the actions of physostigmine.

The E Loop of the Transmitter Binding Site Is a Key Determinant of the Modulatory Effects of Physostigmine on Neuronal Nicotinic α4ß2 Receptors.

Physostigmine is a well known inhibitor of acetylcholinesterase, which can also activate, potentiate, and inhibit acetylcholine receptors, including neuronal nicotinic receptors comprising α4 and ß2 subunits. We have found that the two stoichiometric forms of this receptor differ in the effects of physostigmine. The form containing three copies of α4 and two of ß2 was potentiated at low concentrations of acetylcholine chloride (ACh) and physostigmine, whereas the form containing two copies of α4 and three of ß2 was inhibited. Chimeric constructs of subunits indicated that the presence of inhibition or potentiation depended on the source of the extracellular ligand binding domain of the subunit. Further sets of chimeric constructs demonstrated that a portion of the ACh binding domain, the E loop, is a key determinant. Transferring the E loop from the ß2 subunit to the α4 subunit resulted in strong inhibition, whereas the reciprocal transfer reduced inhibition. To control the number and position of the incorporated chimeric subunits, we expressed chimeric constructs with subunit dimers. Surprisingly, incorporation of a subunit with an altered E loop had similar effects whether it contributed either to an intersubunit interface containing a canonical ACh binding site or to an alternative interface. The observation that the α4 E loop is involved suggests that physostigmine interacts with regions of subunits that contribute to the ACh binding site, whereas the lack of interface specificity indicates that interaction with a particular ACh binding site is not the critical factor.

Potentiation of Neuronal Nicotinic Receptors by 17ß-Estradiol: Roles of the Carboxy-Terminal and the Amino-Terminal Extracellular Domains.

The endogenous steroid 17ß-estradiol (ßEST) potentiates activation of neuronal nicotinic receptors containing α4 subunits. Previous work has shown that the final 4 residues of the α4 subunit are required for potentiation. However, receptors containing the α2 subunit are not potentiated although it has these 4 residues, and only one amino acid difference in the C-terminal tail (FLAGMI vs. WLAGMI). Previous work had indicated that the tryptophan residue was involved in binding an analog of ßEST, but not in potentiation by ßEST. To determine the structural basis for the loss of potentiation we analyzed data from chimeric subunits, which indicated that the major factor underlying the difference between α2 and α4 is the tryptophan/phenylalanine difference, while the N-terminal extracellular domain is a less significant factor. When the tryptophan in α4 was mutated, both phenylalanine and tyrosine conferred lower potentiation while lysine and leucine did not. The reduction reflected a reduced maximal magnitude of potentiation, indicating that the tryptophan is involved in transduction of steroid effects. The regions of the α4 N-terminal extracellular domain involved in potentiation lie near the agonist-binding pocket, rather than close to the membrane or the C-terminal tail, and appear to be involved in transduction rather than binding. These observations indicate that the C-terminal region is involved in both steroid binding (AGMI residues) and transduction (W). The role of the N-terminus appears to be independent of the C-terminal tryptophan and likely reflects an influence on conformational changes caused during channel activation by agonist and potentiation by estradiol.

Analysis of gene expression profiles in response to Sporisorium reilianum f. sp. zeae in maize (Zea mays L.)

Background Head smut of maize, which is caused by Sporisorium reilianum f. sp. zeae (Kühn), is a serious disease in maize. In order to reveal the molecular mechanism of the resistance to head smut in maize, a microarray containing ~ 14,850 probes was used to monitor the gene expression profiles between a disease resistant near isogenic line (NIL) and a highly susceptible inbred line after S. reilianum was injected with an artificial inoculation method. Results Levels of expression for 3,532 genes accounting for 23.8% of the total probes changed after inoculation. Gene Ontology analysis revealed that the differentially expressed genes participated in physiological and biochemical pathways. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that plant-pathogen interaction, natural killer cell mediated cytotoxicity and benzoxazinoid biosynthesis pathways play important roles in resistance to head smut. Three head smut resistance-related candidate genes, CLAVATA1, bassinosteroid insensitive 1-associated receptor kinase 1 and LOC100217307 with leucine-rich repeat (LRR) conserved domains were identified, each of which is in maize mapping bin 2.09, a region previously shown to include a major QTL for head smut resistance. Furthermore, LOC100217307 was validated by quantitative real-time (qRT)-PCR inferring that this gene may be involved in the resistance to head smut of maize. Conclusions This study provided valuable information for cloning, functional analysis and marker assisted breeding of head smut resistance genes.

The nicotinic α5 subunit can replace either an acetylcholine-binding or nonbinding subunit in the α4ß2* neuronal nicotinic receptor.

Heteropentameric neuronal nicotinic receptors assemble so that the canonical acetylcholine-binding sites are located at the interfaces between two pairs of subunits, while the fifth subunit does not participate in a canonical transmitter-binding site. Several subunits are considered to be unable to participate in forming a functional receptor when they occupy a position that would contribute to such a site, including the α5 subunit. The α5 subunit is of interest because of its apparent involvement in nicotine dependence and in the control of dopamine release. We have examined this question using α4 and ß2 subunits in concatemeric constructs with the α5 subunit, expressed in Xenopus oocytes. Using dimeric constructs of α4 and ß2 subunits expressed with free α5 and pentameric constructs incorporating a single copy of α5, we find that the α5 subunit can occupy the position of a nonbinding subunit, or replace a ß2 subunit participating in a canonical binding site. The resulting receptors functionally resemble pentamers assembled with two copies of α4 and three copies of ß2. Functional receptors apparently cannot be formed with α5 subunits in both canonical binding sites. These observations extend the present ideas on the possible positions in the pentamer that may be occupied by the α5 subunit, and suggest that additional physiologic or pharmacological subtypes of neuronal nicotinic receptors may be present in neurons.

A portable site: a binding element for 17ß-estradiol can be placed on any subunit of a nicotinic α4ß2 receptor.

Endogenous steroids can modulate the activity of transmitter-gated channels by directly interacting with the receptor. 17ß-Estradiol potentiates activation of neuronal nicotinic α4ß2 receptors by interacting with a 4 aa sequence at the extreme C terminus of the α4 subunit, but it is not known whether potentiation requires that the sequence be placed on a specific subunit (e.g., an α4 subunit that is involved in forming an acetylcholine-binding site). By using concatemers of subunits and chimeric subunits, we have found that the C-terminal domain can be moved from the α4 to the ß2 subunit and still result in potentiation. In addition, the sequence can be placed on a subunit that contributes to an acetylcholine-binding site or on the structural subunit. The data indicate that this estradiol-binding element is a discrete sequence and suggest that the effect of 17ß-estradiol is mediated by actions on single subunits and that the overall consequences for gating occur because of the summation of independent energetic contributions to overall gating of this receptor.

The effects of change in spousal power on intimate partner violence among Chinese immigrants.

This study explored how changes in power relations within couples after immigrating from more patriarchal societies contribute to intimate partner violence (IPV). Both subjective decision-making power and objective power bases were examined in Chinese immigrant couples. Batterers and nonviolent men both experienced loss of decision-making power in favor of their spouses postimmigration. For the batterers, this loss appeared materialized by lower gains in education and lack of significant gains in income compared to their spouses. However, it was subjective power loss that was related to the batterers' attitudes toward IPV. The study highlights the significance of understanding changes in power dynamics postimmigration among immigrants and the importance of distinguishing between subjective and material power to better capture power imbalance within couples.

Photoaffinity labeling the agonist binding domain of alpha4beta4 and alpha4beta2 neuronal nicotinic acetylcholine receptors with [(125)I]epibatidine and 5[(125)I]A-85380.

The development of nicotinic acetylcholine receptor (nAChR) agonists, particularly those that discriminate between neuronal nAChR subtypes, holds promise as potential therapeutic agents for many neurological diseases and disorders. To this end, we photoaffinity labeled human alpha4beta2 and rat alpha4beta4 nAChRs affinity-purified from stably transfected HEK-293 cells, with the agonists [(125)I]epibatidine and 5[(125)I]A-85380. Our results show that both agonists photoincorporated into the beta4 subunit with little or no labeling of the beta2 and alpha4 subunits respectively. [(125)I]epibatidine labeling in the beta4 subunit was mapped to two overlapping proteolytic fragments that begin at beta4V102 and contain Loop E (beta4I109-P120) of the agonist binding site. We were unable to identify labeled amino acid(s) in Loop E by protein sequencing, but we were able to demonstrate that beta4Q117 in Loop E is the principal site of [(125)I]epibatidine labeling. This was accomplished by substituting residues in the beta2 subunit with the beta4 homologs and finding [(125)I]epibatidine labeling in beta4 and beta2F119Q subunits with little, if any, labeling in alpha4, beta2, or beta2S113R subunits. Finally, functional studies established that the beta2F119/beta4Q117 position is an important determinant of the receptor subtype-selectivity of the agonist 5I-A-85380, affecting both binding affinity and channel activation.

Kinetic analysis of voltage-dependent potentiation and block of the glycine alpha 3 receptor by a neuroactive steroid analogue.

We examined the actions of a carboxylated analogue of pregnanolone ((3alpha,5beta)-20-oxopregnane-3-carboxylic acid; 3alphaCOOH5betaP) on receptors composed of glycine receptor alpha3 subunits, expressed in Xenopus oocytes. This analogue both inhibits and potentiates this receptor; potentiation increases with more negative membrane potentials while block increases with less negative membrane potentials. We used a second analogue ((3alpha,5beta)-3-hydroxymethylpregnan-20-one; 3alphaCH(2)OH5betaP) to examine the mechanism for voltage-dependent potentiation. This analogue potentiates but does not block the glycine alpha3 receptor. Steady-state responses and current relaxations following voltage jumps support the idea that the voltage dependence of potentiation indirectly arises from a voltage dependence for channel activation by glycine, rather than an intrinsic voltage dependence for potentiation. Potentiation results from a slowing of the channel deactivation rate. In the absence of steroid, at a low [glycine] current relaxations after a voltage jump show two exponential components, with a weighted average time constant of approximately 425 ms (-50 mV, 22 degrees C). The rate for channel deactivation increases at more negative potentials (e-fold per 170 mV) whereas activation decreases (e-fold per 230 mV). The probability a channel is active at a high [glycine] is greater than 0.9. The addition of 10 microM 3alphaCH(2)OH5betaP decreases the deactivation rate by 6.3-fold (-50 mV). Voltage-dependent block by 3alphaCOOH5betaP is consistent with simple open-channel block, with voltage dependence reflecting interactions of the charge on the analogue with the electrical field. Block and unblock have equal but opposite dependence on membrane potential, and the charge on 3alphaCOOH5betaP senses approximately 70% of the membrane field at the blocking site. The apparent forward rate for block, however, is very slow (2 x 10(5) m(-1) s(-1)).

Hostile attributional bias, early abuse, and social desirability in reporting hostile attributions among Chinese immigrant batterers and nonviolent men.

This study examined differences in reporting hostile attributional bias (HAB) between court-referred Chinese immigrant batterers and a nonviolent community sample. It measured social desirability (SD) in their reporting of HAB by including an SD measure and a covert indirect measure of HAB. Further, it explored the relationship between HAB and childhood exposure to violence. The batterers scored lower on the overt measure but higher on the covert measure of HAB. Their scores on the overt measure were negatively correlated with their SD scores. Childhood exposure to violence was positively correlated with HAB among the batterers but not among the nonviolent men. The role of HAB in intimate partner violence needs more research, and future studies and batterer interventions need to consider SD in assessing and addressing HAB.

Neuroactive steroids and human recombinant rho1 GABAC receptors.

The gamma-aminobutyric acid type C (GABAC) receptor is structurally related to the GABAA receptors, yet quite distinct physiologically and pharmacologically. Neuroactive steroids are known to be potent and efficacious modulators of the GABAA receptor, but they are less well characterized in their actions on the GABAC receptor. We have examined the actions of neuroactive steroids and analogs on rho1 (GABAC) receptors expressed in Xenopus laevis oocytes, with two goals in mind. First, we tested a larger number of endogenous steroids, to determine whether particularly potent steroids could be found. Second, we examined the structure-activity relationship for steroid actions, and some mechanistic features, to determine the possible numbers of steroid binding sites and mechanisms of action. In total, 41 compounds were examined. Estradiols are inhibitors, essentially equipotent with picrotoxinin. No endogenous steroid tested was highly efficacious at potentiation. The results of the structure-activity studies and the effects of two mutations to the second transmembrane region of the rho1 GABAC receptor indicate that there are several mechanisms by which steroids can inhibit the receptor. Surprisingly, estradiol shares some features with picrotoxin. Inhibition by negatively charged compounds was not sensitive to membrane potential, and inhibition by all compounds tested was reduced at higher concentrations of GABA. The data indicate that the binding sites mediating potentiation and inhibition differ from each other and that there are several (three or more) mechanisms for producing inhibition.

Acute p38-mediated modulation of tetrodotoxin-resistant sodium channels in mouse sensory neurons by tumor necrosis factor-alpha.

Tumor necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine involved in the development and maintenance of inflammatory and neuropathic pain conditions. TNFalpha can have long-lasting effects by regulating the expression of a variety of inflammatory mediators, including other cytokines and TNFalpha itself. However, the speed with which TNFalpha induces tactile and thermal hypersensitivity suggests that transcriptional regulation cannot fully account for its sensitizing effects, and some recent findings suggest that TNFalpha may act directly on primary afferent neurons to induce pain hypersensitivity. In the present study, we show that peripheral administration of TNFalpha induces thermal hypersensitivity in wild-type mice but not in transient receptor potential vanilloid receptor TRPV1(-/-) mice. In contrast, TNFalpha produced equivalent mechanical hypersensitivity in TRPV1(-/-) mice and wild-type littermates, suggesting a role for TRPV1 in TNFalpha-induced thermal, but not mechanical, hypersensitivity. Because tetrodotoxin (TTX)-resistant Na+ channels are a critical site of modulation underlying mechanical hypersensitivity in inflammatory and neuropathic pain conditions, we tested the effects of TNFalpha on these channels in isolated mouse dorsal root ganglion (DRG) neurons. We report that acute application of TNFalpha rapidly enhances TTX-resistant Na+ currents in isolated DRG neurons. This potentiation of TTX-resistant currents by TNFalpha is dramatically reduced in DRG neurons from TNF receptor 1 (TNFR1) knock-out mice and is blocked by the p38 mitogen-activated protein kinase inhibitor SB202190 [4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole]. Mechanical hypersensitivity induced by peripherally applied TNFalpha is also significantly reduced by SB202190. These results suggest that TNFalpha may induce acute peripheral mechanical sensitization by acting directly on TNFR1 in primary afferent neurons, resulting in p38-dependent modulation of TTX-resistant Na+ channels.

Protein and gene expression of Ca2+ channel isoforms in murine colon: effect of inflammation.

L-Type voltage-dependent Ca2+ channels (L-VDCC) mediate calcium influx in response to membrane depolarization and regulate intracellular processes such as contraction, secretion, neurotransmission, and gene expression. Colonic inflammation significantly attenuates calcium currents in smooth muscle; however, the basis for this remains unclear. In this study we examined the protein and mRNA expression of two isoforms of Ca(v)1.2, encoded by either exon la or 1b. Both isoforms were detected by Western blots, immunohistochemistry and RT-PCR in smooth muscle cells. Neither the protein nor mRNA expression measured by real-time PCR of either isoforms was affected in colonic myocytes from dextran sulfate sodium-treated mice. In whole-cell voltage-clamp experiments, the amplitude of the calcium currents were decreased by almost 70% by inflammation. The calcium channel currents were attenuated by 50 +/- 3% by the c-src kinase specific inhibitor, PP2, in control cells but only 19 +/- 7% in cells from inflamed mice. These studies suggest that decreased calcium channel currents following colonic inflammation are not due to decreased expression but may result from altered regulation by the non-receptor cellular tyrosine kinase, c-src kinase.