HSV vector-mediated GAD67 suppresses neuropathic pain induced by perineural HIV gp120 in rats through inhibition of ROS and Wnt5a.

Human immunodeficiency virus (HIV)-related neuropathic pain is a debilitating chronic condition that is severe and unrelenting. Despite the extensive research, the exact neuropathological mechanisms remain unknown, which hinders our ability to develop effective treatments. Loss of GABAergic tone may have an important role in the neuropathic pain state. Glutamic acid decarboxylase 67 (GAD67) is one of the isoforms that catalyze GABA synthesis. Here, we used recombinant herpes simplex virus (HSV-1) vectors that encode gad1 gene to evaluate the therapeutic potential of GAD67 in peripheral HIV gp120-induced neuropathic pain in rats. We found that (1) subcutaneous inoculation of the HSV vectors expressing GAD67 attenuated mechanical allodynia in the model of HIV gp120-induced neuropathic pain, (2) the anti-allodynic effect of GAD67 was reduced by GABA-A and-B receptors antagonists, (3) HSV vectors expressing GAD67 reversed the lowered GABA-IR expression and (4) the HSV vectors expressing GAD67 suppressed the upregulated mitochondrial superoxide and Wnt5a in the spinal dorsal horn. Taken together, our studies support the concept that recovering GABAergic tone by the HSV vectors may reverse HIV-associated neuropathic pain through suppressing mitochondrial superoxide and Wnt5a. Our studies provide validation of HSV-mediated GAD67 gene therapy in the treatment of HIV-related neuropathic pain.

HSV-mediated p55TNFSR reduces neuropathic pain induced by HIV gp120 in rats through CXCR4 activity.

Human immunodeficiency virus (HIV)-related neuropathic pain is a debilitating chronic condition that is severe and unrelenting. Despite extensive research, the detailed neuropathological mechanisms remain unknown, which hinders our ability to develop effective treatments. In this study, we investigated the role of proinflammatory molecules, tumor necrosis factor-α (TNFα), CXCR4 and stromal-derived factor-1 α (SDF1α), in the L4/5 dorsal root ganglia (DRG) and the spinal dorsal horn in HIV gp120 protein-mediated neuropathic pain. Our results showed that the application of HIV gp120 to the sciatic nerve induced upregulation of TNFα, CXCR4 and SDF1α in both the DRG and the lumbar spinal dorsal horn. Non-replicating herpes simplex virus (HSV) vector encoding the p55TNFSR gene and producing a TNF-soluble receptor (TNFSR) to block bioactivity of TNFα reversed mechanical allodynia. Intrathecal AMD3100 (CXCR4 antagonist) increased mechanical threshold. The HSV vectors expressing p55TNFSR reversed upregulation of TNFα, CXCR4 and SDF1α induced by gp120 in the DRG and the spinal dorsal horn. These studies suggest that proinflammatory TNFα to the CXCR4/SDF1 pathway has an important role in the HIV-related neuropathic pain state and that blocking the proinflammatory cytokines or chemokines is able to reduce neuropathic pain. This work provides a novel gene therapy proof-of-concept for HIV-associated neuropathic pain.

Linkage analysis of susceptibility to ozone-induced lung inflammation in inbred mice.

Exposures to the common air pollutant ozone (O3) cause decrements in pulmonary function and induce airway inflammation that is characterized by infiltration of polymorphonuclear neutrophils (PMNs; refs 1-4). Because of the impact that O3 may have on public health, it is critical to identify susceptibility factors. Highly reproducible, significant inter-individual variations in human pulmonary function responses to O3 support the hypothesis that genetic background is an important determinant. Initial analysis of PMN responses to O3 exposure in segregant populations derived from inflammation-prone (susceptible) C57BL/6J (B6) and inflammation-resistant C3H/HeJ (C3) inbred mice indicated that susceptibility was controlled by a locus we termed Inf2 (ref. 7). Subsequent analyses with recombinant inbred strains suggested that a more complex interaction of genes is involved. In this report, we identify a quantitative trait locus (QTL) for O3 susceptibility on chromosome 17. Candidate genes for the locus include Tnf, the gene encoding the pro-inflammatory cytokine tumour necrosis factor-alpha (Tnf). Antibody neutralization of the protein product of this putative candidate gene significantly protected against O3 injury in susceptible mice. These results strongly support linkage of O3 susceptibility to a QTL on chromosome 17 and Tnf as a candidate gene.

The Ah locus: biochemical basis for genetic differences in brain tumor formation in mice.

Allelic differences at the Ah locus are showen to exist in the mouse brain. This finding probably explains inbred mouse strain differences in polycyclic hydrocarbon tumorigenesis of the brain described more than 35 years ago and may be important in understanding the etiology of genetic differences in certain human intracranial neoplasms.

UGRP1, a uteroglobin/Clara cell secretory protein-related protein, is a novel lung-enriched downstream target gene for the T/EBP/NKX2.1 homeodomain transcription factor.

A novel gene that is down-regulated in lungs of T/ebp/Nkx2.1-null mouse embryos has been identified using a suppressive-subtractive hybridization method. The gene product is a secreted protein, forms a homodimer, and exhibits an amino acid sequence similar to that seen in the uteroglobin/Clara cell secretory protein family of proteins. This gene, designated Ugrp1 (uteroglobin-related protein 1), consists of three exons and two introns and produces three transcripts by alternative splicing. The Ugrp1 gene was localized by fluorescence in situ hybridization to mouse chromosome 18 at region 18C-D; this region is homologous with human 5q31-34, where one of the asthma susceptibility genes has been assigned. UGRP1 mRNA is predominantly expressed in the lung, with low levels of expression in the thyroid. Expression in the lung is detectable as early as embryonic day 12.5 and increases markedly by embryonic day 16.5. In T/ebp/Nkx2.1-null embryo lungs, UGRP1 expression was significantly reduced as assessed by RT-PCR analysis. Cotransfection assays using a T/EBP/NKX2.1 expression construct with Ugrp1 promoter-luciferase reporter constructs confirmed that T/EBP/NKX2.1 regulates Ugrp1 gene activity at the transcriptional level. Thus, Ugrp1 is a downstream target gene for the T/EBP/NKX2.1 homeodomain transcription factor. Changes in UGRP1 mRNA levels in lungs from antigen-sensitized mice suggest the possible involvement of UGRP1 in inflammation.

Neuropathic ocular pain: an important yet underevaluated feature of dry eye.

Dry eye has gained recognition as a public health problem given its prevalence, morbidity, and cost implications. Dry eye can have a variety of symptoms including blurred vision, irritation, and ocular pain. Within dry eye-associated ocular pain, some patients report transient pain whereas others complain of chronic pain. In this review, we will summarize the evidence that chronicity is more likely to occur in patients with dysfunction in their ocular sensory apparatus (ie, neuropathic ocular pain). Clinical evidence of dysfunction includes the presence of spontaneous dysesthesias, allodynia, hyperalgesia, and corneal nerve morphologic and functional abnormalities. Both peripheral and central sensitizations likely play a role in generating the noted clinical characteristics. We will further discuss how evaluating for neuropathic ocular pain may affect the treatment of dry eye-associated chronic pain.

Role of insulin receptor substrate-2 in interleukin-9-dependent proliferation.

Interleukin-9 (IL-9) stimulation results in JAK, STAT and IRS1/2 phosphorylation. The role of IRS adaptor proteins in IL-9 signaling is not clear. We show that IL-9 induces IRS2 phosphorylation and association with phosphatidylinositol-3 kinase (PI 3-K) p85 subunit in TS1 cells and BaF/9R cells, which proliferate upon IL-9 stimulation. We observed a PI 3-K-dependent phosphorylation of protein kinase B (PKB) in TS1 cells, but not in BaF/9R, nor in other IL-9-dependent cell lines. Finally, 32D cells that were transfected with the IL-9 receptor but lack IRS expression survived in the presence of IL-9. Ectopic IRS1 expression allowed for IL-9-induced proliferation, in the absence of significant PKB phosphorylation.

Autosomal recessive inheritance of airway hyperreactivity to 5-hydroxytryptamine.

We have previously reported that airway hyperresponsiveness to acetylcholine (ACh) is inherited as an autosomal recessive trait in A/J and C3H/HeJ mice and the progeny of crosses between them (FASEB J. 2: 2605-2608, 1988). In the present report, we have extended these studies by evaluating the biological variability in the airway response to 5-hydroxytryptamine (5-HT) and ACh among multiple genetically standardized inbred strains of mice. The pattern of airway responsiveness to ACh differed significantly from that of 5-HT in nine inbred strains of mice. A/J mice showed nonspecific airway hyperresponsiveness to both 5-HT and ACh. DBA/2J mice were hyperresponsive to 5-HT but not to ACh. An airway phenotype that resembled these inbred strains is termed HYPERREACTIVE. The C3H/HeJ and C57BL/6J inbred strains were minimally reactive to either ACh or 5-HT. Airway phenotypes that resembled these minimally reactive strains are termed HYPOREACTIVE. The frequency of HYPERRACTIVE and HYPOREACTIVE offspring from crosses between A/J and C3H/HeJ mice or DBA/2J and C57BL/6J mice is consistent with a single autosomal recessive gene, primarily determining airway hyperresponsiveness to 5-HT. We report linkage studies which suggest that these genes are not closely linked and that 5-HT and ACh airway hyperresponsiveness is inherited independently. The results of these studies suggest that murine nonspecific airway hyperresponsiveness is determined by multiple genes.

Succinylcholine potentiates responses to intravenous acetylcholine in the canine lung periphery.

Using the wedged bronchoscope technique to measure collateral resistance (Rcs), we evaluated the effect of succinylcholine (SCh) on the response to acetylcholine (ACh) and methacholine (MCh) in the lung periphery in six mongrel dogs. Dogs were anesthetized, intubated, and mechanically ventilated. After a stable baseline Rcs was obtained, responses to intravenous ACh (25-200 micrograms), intravenous MCh (3-30 micrograms), and aerosolized ACh (30-100 micrograms/ml for 15 s) were measured. We compared the Rcs responses with 1) ACh alone, 2) ACh 2 min after SCh (0.5 mg/kg), 3) ACh 2 min after SCh and during hexamethonium infusion (5 mg/kg + 10 mg.kg-1.h-1), 4) MCh 2 min after SCh, and 5) ACh aerosol 2 min after SCh. SCh did not significantly alter baseline airway tone. SCh increased the Rcs response to ACh by 48 +/- 17% (SE) (P less than 0.01). SCh in the presence of hexamethonium increased the Rcs response by 10 +/- 3% (P less than 0.05), while hexamethonium itself increased the response to ACh by 69 +/- 27%. Because SCh did not increase the Rcs response to intravenous MCh or to aerosolized ACh, SCh probably enhances airway reactivity to intravenous ACh by competing for pseudocholinesterase in plasma. We conclude that the level of muscle relaxant must be taken into account in interpreting studies of airway reactivity when intravenous ACh is employed.

In vitro tracheal responses from mice chosen for in vivo lung cholinergic sensitivity.

We selected two inbred strains of mice based on their different in vivo lung responses to intravenous acetylcholine for studies on the in vitro tracheal responses to contractile and relaxing agents. In addition, we studied the role of cyclooxygenase products on the in vitro responses. Tracheal rings were contracted with increasing concentrations of carbachol and KCl and relaxed with increasing concentrations of isoproterenol after contraction with carbachol at the concentration that produced 30, 50, and 70% of the maximal contraction (EC30, EC50, and EC70, respectively) and KCl at the EC50. Half the tracheae simultaneously underwent the same protocols after pretreatment with indomethacin (3 X 10(-6) M). Despite a severalfold difference in the maximal response to cholinergic agents in vivo, there were no significant differences between the strains in the tracheal responses to carbachol (P = 0.78) or KCl (P = 0.13) in vitro. Both strains showed inhibition of the isoproterenol relaxation by carbachol (P less than 0.0001). Multiple linear regression analysis showed that the strain that was more sensitive to carbachol in vivo was also more sensitive to isoproterenol in vitro after carbachol contraction (P = 0.014). The greater isoproterenol sensitivity of the tracheae from this strain was not present after contraction with KCl, nor were these tracheae more sensitive to relaxation with sodium nitroprusside. Indomethacin pretreatment of the tissues in vitro augmented the maximal response and the sensitivity to carbachol (P less than 0.001) and KCl (P = 0.0006), and this effect was similar in both strains. Evaluation of isoproterenol relaxation after indomethacin pretreatment was confounded by the lower concentrations of carbachol needed for contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic control of differential baseline breathing pattern.

The purpose of the present study was to determine the genetic control of baseline breathing pattern by examining the mode of inheritance between two inbred murine strains with differential breathing characteristics. Specifically, the rapid, shallow phenotype of the C57BL/6J (B6) strain is consistently distinct from the slow, deep phenotype of the C3H/HeJ (C3) strain. The response distributions of segregant and nonsegregant progeny were compared with the two progenitor strains to determine the mode of inheritance for each ventilatory characteristic. The BXH recombinant inbred (RI) strains derived from the B6 and C3 progenitors were examined to establish strain distribution patterns for each ventilatory trait. To establish the mode of inheritance, baseline breathing frequency (f), tidal volume, and inspiratory time (TI) were measured five times in each of 178 mature male animals from the two progenitor strains and their progeny by using whole body plethysmography. With respect to f and TI, the two progenitor strains were consistently distinct, and segregation analyses of the inheritance pattern suggest that the most parsimonious genetic model for response distributions of f and TI is a two-loci model. In similar experiments conducted on 82 mature male animals from 12 BXH RI strains, each parental phenotype was represented by one or more of the RI strains. Intermediate phenotypes emerged to confirm the likelihood that parental strain differences in f and TI were determined by more than one locus. Taken together, these studies suggest that the phenotypic difference in baseline respiratory timing between male B6 and C3 mice is best explained by a genetic model that considers at least two loci as major determinants.

Molecular genetic methods for mapping disease genes.

Recent technological enhancements in molecular genetics have significantly improved our ability to locate disease genes by linkage analysis. Despite the introduction of molecular methods such as PCR and the discovery of highly polymorphic SSRs, genotyping is still rate-limiting for localizing disease genes by linkage. These methods have been, until recently, highly technical, time-consuming, and expensive. The challenge of mapping the major genes that render one susceptible to environmentally initiated lung disorders such as asthma will require efficient and highly accurate methods of genotyping. We have shown that genotyping by semi-automated fluorescence-based techniques is both highly accurate and efficient. These methods may improve productivity by more than an order of magnitude and can be easily adapted to most linkage studies.

Polymorphisms in the transcribed 3' untranslated region of eukaryotic genes.

In this review we present preliminary evidence for a new class of polymorphism that may be used in a systematic way to map cDNAs efficiently and to expedite the construction of a high-resolution genetic map of the human genome. Ultimately, transcribed 3' untranslated polymorphisms will warrant further study because they should be widely distributed throughout the genome within transcribed sequences, and they can be readily identified as a result of cDNA cloning and sequencing. Furthermore, these markers should be universally available on the basis of the sequence data and highly useful in linkage analyses.

Prospects for the diagnosis of malignant hyperthermia susceptibility using molecular genetic approaches.

MHS is a heterogeneous pharmacogenetic disorder in the human that is likely to be caused by one of a variety of genetic defects, in one of a number of genes. Direct molecular methods will provide a rapid, efficient, non-invasive, and low-cost screening test once the causative genetic mutations have been identified. However, until this objective is met, indirect molecular genetic methods can be used to demonstrate the inheritance of an abnormal gene in certain family members at risk. This requires localizing the gene that produces the abnormal phenotype to a subchromosomal segment by linkage analysis and showing the coinheritance of MHS and DNA markers in a number of family members. Indirect molecular genetic methods are likely to be particularly useful in the diagnostic evaluation of children too small to be biopsied in families where others have been biopsied or their phenotypes are known. It appears likely that molecular genetic methods will not eliminate the usefulness of the muscle biopsy and caffeine-halothane contracture test in the near future. Rather, these diagnostic tests will complement one another and significantly improve our understanding of the complexity of this disorder.

Genetic susceptibility to atracurium-induced bronchoconstriction.

The goal of this study was to develop a murine model of atracurium-induced bronchoconstriction in which to evaluate the mechanism of action of this airway response. We evaluated nine inbred strains of mice for the development of atracurium-induced bronchoconstriction. The maximal difference in the magnitude of the airway response to atracurium noted between the highly responsive DBA/2 mice and the minimally responsive SJL mice was greater than 20-fold. This phenotype appears to reflect an intrinsic difference in the lungs of these animals because the extent of neuromuscular blockade was not significantly different in DBA/2 and SJL mice. Atracurium-induced airway hyperresponsiveness in DBA/2 mice was eliminated in a dose-dependent manner by pretreatment with atropine or pancuronium. These data are consistent with a postganglionic vagal efferent mechanism which produces a differential pulmonary response to this neuromuscular blocker. A genetic predisposition to atracurium-induced bronchoconstriction appears to exist in certain inbred strains of mice. Thus, a mouse model may be useful for mapping the gene(s) that control this trait and for suggesting responsible candidate genes. Our results suggest that the inbred laboratory mouse will be useful to study the mechanism by which atracurium produces bronchoconstriction.

Expression of airway hyperreactivity to acetylcholine as a simple autosomal recessive trait in mice.

An increased airway response to various bronchoconstricting agents is one of the hallmarks of asthma. An interdependence of heredity and environment appears to determine this nonspecific hyperreactivity of the airways. The present study describes the patterns of inheritance of the airway response to a direct mediator of smooth muscle contraction (acetylcholine) in A/J and C3H/HeJ inbred mice and their offspring. The mean airway response to acetylcholine was greater than sixfold higher in A/J mice as compared with C3H/HeJ mice. Two phenotypes were easily distinguished on the basis of airway responses to acetylcholine in the progeny of A/J and C3H/HeJ mice. These two phenotypes were termed HYPERREACTIVE (after the A/J strain) and HYPOREACTIVE (after the C3H/HeJ strain). The observed frequencies of HYPERREACTIVE and HYPOREACTIVE phenotypes in the (A/J x C3H/HeJ) F1; (C3H/HeJ x A/J) F1 x C3H/HeJ (C3H/HeJ backcross); and the [(A/J x C3H/HeJ) F1 x (C3H/HeJ x A/J) F1] F2 are consistent with a single autosomal recessive gene primarily controlling acetylcholine-mediated airway responses. This single gene difference in airway response is completely inhibited by atropine and therefore mediated entirely by the muscarinic acetylcholine receptor.

Susceptibility to ozone-induced inflammation. I. Genetic control of the response to subacute exposure.

We demonstrated previously that C57BL/6J (B6) inbred mice are susceptible and C3H/HeJ (C3) mice are resistant to airway inflammation that is induced by acute (3 h) exposure to 2 parts per million (ppm) ozone (O3). In the present study we tested the hypothesis that B6 and C3 mice are also differentially susceptible to the airway inflammatory responses to subacute (72 h) exposure to environmentally relevant concentrations of O3 (0.12 and 0.30 ppm). Male mice (20-25 g, 5-7 wk) were exposed continuously to 0.12 ppm O3, 0.30 ppm O3, or filtered air (control). Pulmonary inflammation was assessed after 24, 48, and 72 h by differential cell count and total protein in bronchoalveolar lavage (BAL) returns. Exposure to 0.12 ppm O3 caused significant influx of alveolar macrophages, polymorphonuclear leukocytes (PMNs), lymphocytes, and total BAL protein in both strains, but no differences in the magnitude of the responses were found between B6 and C3 mice. In contrast to the effect of 0.12 ppm O3, exposure to 0.30 ppm O3 elicited significantly greater numbers of inflammatory cells and BAL protein concentration in B6 mice relative to C3 mice. The phenotypes of the B6 and C3 mice were termed susceptible and resistant, respectively. To further evaluate the potential genetic contribution to the inflammatory response to 0.30 ppm O3, the F1, F2, and backcross progeny from B6 and C3 progenitors were examined. The ratios of susceptible and resistant phenotypes of these progeny support the hypothesis that a single autosomal recessive gene confers susceptibility to subacute O3-induced inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)