IL4Rα and ADAM33 as genetic markers in asthma exacerbations and type-2 inflammatory endotype.

BACKGROUND: Genetic markers of susceptibility to asthma exacerbations in adults remain unclear. OBJECTIVE: To identify genetic markers of asthma exacerbations, particularly in patients with type-2 inflammatory endotype. METHODS: In this observational study of patients enrolled in the Kinki Hokuriku Airway disease Conference multicenter study, frequency of exacerbations requiring systemic corticosteroids during 2 years after enrolment and associated risk factors was determined. For genetic marker analysis, interleukin-4 receptor α (IL4RA) rs8832 and a disintegrin and metalloprotease 33 (ADAM33) S_2 (rs528557), T_1 (rs2280091), T_2 (rs2280090), and V_4 (rs2787094) variants were included. Elevated serum periostin levels at enrolment (≥95 ng/mL, defined as type-2 inflammatory endotype) were considered in the analysis. RESULTS: Among 217 patients who were successfully followed up for 2 years after enrolment, 60 patients showed at least one asthma exacerbation during the 2 years. Airflow limitation (%FEV1 <80%) and recent exacerbations but not genetic variants were identified as risk markers of exacerbations. A total of 27 patients showed type-2 inflammatory endotype (serum periostin ≥95 ng/mL at enrolment) and subsequent exacerbations; risk factors in these patients were airflow limitation (odds ratio, 6.51; 95% confidence interval (CI): 2.37-18.6; P=.0003), GG genotype of IL4RA rs8832 (odds ratio, 4.01; 95% CI: 1.47-11.0; P=.007), and A allele of ADAM33 T_2 (odds ratio, 2.81; 95% CI: 1.05-7.67; P=.04) by multivariate analysis. In addition, GG genotype of IL4RA rs8832 was associated with type-2 endotype, whereas A allele of ADAM33 T_2 was associated with mixed type of eosinophilic/type-2 and neutrophilic inflammations. CONCLUSIONS AND CLINICAL RELEVANCE: IL4RA and ADAM33 variants may be risk markers of asthma exacerbations in type-2 inflammatory endotype. Precise endotyping may facilitate the identification of genetic risk markers of asthma exacerbations.

Recent advance in investigation of gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a complex clinical syndrome characterised by severe asthmatic attack upon treatment with aspirin and/or non-steroidal anti-inflammatory drugs (NSAIDs). Genetic predisposition has been considered as a crucial determinant and candidate genes have concentrated especially on cysteinyl leukotrienes (LTs)- related genes as the inhibitory action of aspirin and NSAIDs on cyclooxygenase activity may cause overproduction of cysteinyl LTs. However, conflicting results have been reported, in parallel with replication studies in different ethnic groups. Thus, future areas of investigations need to focus on comprehensive approaches towards the discovery of other genetic biomarkers. Unfortunately, few papers have been reported about gene polymorphisms in Japanese patients with AERD. Here, we described on our recent genetic investigations on B2ADR, IL-13, IL-17A, CYP2C19, TBXA2R, CRTH2 and HSP70. This review indicates potential genetic biomarkers contributing to the early diagnosis of AERD, which may include CYP2C19 and HSP70 gene polymorphisms, and future validation studies in independent population are required to provide reassurance about our findings

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Recent advance in investigation of gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease.

Aspirin-exacerbated respiratory disease (AERD) is a complex clinical syndrome characterised by severe asthmatic attack upon treatment with aspirin and/or non-steroidal anti-inflammatory drugs (NSAIDs). Genetic predisposition has been considered as a crucial determinant and candidate genes have concentrated especially on cysteinyl leukotrienes (LTs)-related genes as the inhibitory action of aspirin and NSAIDs on cyclooxygenase activity may cause overproduction of cysteinyl LTs. However, conflicting results have been reported, in parallel with replication studies in different ethnic groups. Thus, future areas of investigations need to focus on comprehensive approaches towards the discovery of other genetic biomarkers. Unfortunately, few papers have been reported about gene polymorphisms in Japanese patients with AERD. Here, we described on our recent genetic investigations on B2ADR, IL-13, IL-17A, CYP2C19, TBXA2R, CRTH2 and HSP70. This review indicates potential genetic biomarkers contributing to the early diagnosis of AERD, which may include CYP2C19 and HSP70 gene polymorphisms, and future validation studies in independent population are required to provide reassurance about our findings.

GLCCI1 variant accelerates pulmonary function decline in patients with asthma receiving inhaled corticosteroids.

BACKGROUND: In steroid-naive patients with asthma, several gene variants are associated with a short-term response to inhaled corticosteroid (ICS) treatment; this has mostly been observed in Caucasians. However, not many studies have been conducted for other ethnicities. Here, we aimed to determine the relationship between the annual decline in forced expiratory flow volume in one second (FEV1 ) and the variant of the glucocorticoid-induced transcript 1 gene (GLCCI1) in Japanese patients with asthma receiving long-term ICS treatment, taking into account the effect of high serum periostin levels, a known association factor of pulmonary function decline and a marker of refractory eosinophilic/Th2 inflammation. METHODS: In this study, 224 patients with asthma receiving ICS treatment for at least 4 years were enrolled. The effects of single-nucleotide polymorphisms (SNPs) in GLCCI1, stress-induced phosphoprotein 1 (STIP1), and T gene on the decline in FEV1 of 30 ml/year or greater were determined. RESULTS: Besides the known contributing factors, that is, the most intensive treatment step, ex-smoking, and high serum periostin levels (≥95 ng/ml), the GG genotype of GLCCI1 rs37973, and not other SNPs, was independently associated with a decline in FEV1 of 30 ml/year or greater. When patients were stratified according to their serum periostin levels, the GG genotype of rs37973 was significantly associated with blood eosinophilia (≥250/µl) in the high serum periostin group. CONCLUSIONS: A GLCCI1 variant is a risk factor of pulmonary function decline in Japanese patients with asthma receiving long-term ICS treatment. Thus, GLCCI1 may be associated with response to ICS across ethnicities.

Dynamic change of cells expressing MMP-2 mRNA and MT1-MMP mRNA in the recovery from liver fibrosis in the rat.

BACKGROUND/AIMS: The aim of this study was to investigate whether both matrix metalloproteinase-2 (MMP-2) and membrane type 1 MMP (MT1-MMP) participate in the spontaneous resolution of liver fibrosis. METHODS: Transcription of both genes was examined by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Gelatinase activity was investigated by zymography. RESULTS: Gene expression by RT-PCR showed that both genes increased in the process of liver fibrosis, then decreased gradually in the recovery phase. ISH revealed that distribution of positive cells changed quickly in the recovery phase. Positive cells were widely seen in the liver, mainly around fibrous septa, in the aggressive phase, but were exclusively observed at the interface between the resolving fibrous band and the parenchyma, then were diffusely located in the lobules in the recovery phase. Main cells expressing both mRNAs seemed to be stellate cells for their morphology, though they did not express characteristic cell markers. Some hepatocytes and Kupffer cells expressed both mRNAs in the recovery phase. Gelatinase activity of MMP-2 increased in the recovery phase of 8-week-treated rat liver by gelatin zymography. CONCLUSIONS: The results of present study suggest that both enzymes participate in the destruction of extracellular matrix in coordination with MMP-13.

Reversibility of hepatic fibrosis: from the first report of collagenase in the liver to the possibility of gene therapy for recovery.

Since the authors reported the presence of collagenase in the liver as well as its increased activity in the early stage of hepatic fibrosis and its reduced activity in advanced fibrosis in rats induced by chronic CCl4 intoxication, in baboons fed alcohol chronically and in patients with alcoholic fibrosis, other investigators have demonstrated the same tendency of collagenase activity biologically and histochemically. Very recently, the authors demonstrated definite gene expression of collagenase during the recovery from experimental hepatic fibrosis using Northern blotting and in situ hybridization. The findings of in situ hybridization not only demonstrated the cells expressing collagenase, but also suggested much information on the mechanism of the recovery from fibrosis. Hepatic stellate cells play a key role not only in fibrogenesis but also in fibrolysis. The authors' recent observation revealed that collagenase (matrix metalloproteinase-13 (MMP-13)) gene expression appears very early in the process of recovery from liver fibrosis, and that both stellate cells and hepatocytes express MMP-13. Recovery from liver cirrhosis requires the gene expression of collagenase, increased production of the collagenase enzyme, and activation of the enzyme balanced with the specific inhibitors of collagenase. The understanding of molecular mechanisms of MMP-1 gene expression which is under investigation in our laboratory may provide us a new strategy for the treatment of liver fibrosis including the possibility of gene therapy.

Multiple logistic regression analysis of risk factors for the development of steroid-dependent asthma in the elderly: a comparison with younger asthmatics.

BACKGROUND: The percentage of the aged among all patients with bronchial asthma is increasing. OBJECTIVE: To investigate the risk factors for the development of steroid-dependent asthma in the elderly. METHODS: A multiple logistic regression analysis involving various clinical factors between steroid-dependent and -independent asthma was carried out for 59 asthmatics aged over 60 years, including 16 patients with steroid-dependent asthma. The calculated risk for each factor was compared with that obtained from 122 younger asthmatics aged 20-59 years. RESULTS: Among the factors examined (sex, age, period from onset of asthma, type of asthma and family history of asthma, plus history of smoking, atopic dermatitis, allergic rhinitis, chronic sinusitis and nasal polyps), the significant risk factors for the development of steroid dependency in the elderly asthmatics were only family history of bronchial asthma (relative risk 3.6) and smoking history (relative risk 6.9). CONCLUSIONS: Some risk factors for steroid-dependent asthma in younger individuals were not significant in the elderly. Since the smoking history was most closely associated with the development of steroid dependency in the elderly, even though most of them had quit smoking, it is important for patients with asthma to avoid smoking.

Gene expression of interstitial collagenase in both progressive and recovery phase of rat liver fibrosis induced by carbon tetrachloride.

BACKGROUND/AIMS: Liver fibrosis is a dynamic state between matrix production and degradation. Since our report in 1974, many studies have examined collagenase and liver fibrosis, but not the identification of cells responsible for collagenase production in vivo. The aim of this study was to investigate the gene expression of interstitial collagenase in the progressive and recovery phases of experimental rat liver fibrosis by in situ hybridization. METHODS: We examined the gene expression of interstitial collagenase (MMP-13) in the progressive and recovery phase of experimental rat liver fibrosis induced by chronic CCl4 intoxication by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. In order to identify the cells expressing MMP-13 mRNA by in situ hybridization, immunohistochemistry was performed using serial sections. RESULTS: In normal rat liver, a faint band for MMP-13 mRNA was observed by RT-PCR, but not by in situ hybridization. The livers of rats treated with CCl4 for 4 weeks showed fatty metamorphosis but no definite fibrosis. Positive signals for MMP-13 mRNA were observed in scattered mesenchymal cells, within lobules which seem to be stellate cells from immunohistochemical staining. Once the fibrosis became prominent, the faint band for MMP-13 mRNA was detected only by RT-PCR and very few signals, if any, by in situ hybridization. On the other hand, in the recovery phase of liver fibrosis, gene expression of MMP-13 was markedly enhanced. Strong positive cells by in situ hybridization were observed mainly at the interface between the resolving fibrous septa and the parenchyma. Overlapping both images of in situ hybridization and immunohistochemical staining with the help of a computer revealed that some positive cells, but not all cells, were stellate cells stained with a-smooth muscle actin antibody. CONCLUSIONS: MMP-13 participates in the degradation of newly-formed matrix in the recovery from rat liver fibrosis more than in the remodeling of extracellular matrix for the formation of fibrosis. Hepatic stellate cells play a crucial role in MMP-13 production in the recovery from fibrosis, though not all stellate cells were positive for MMP-13 mRNA. Further investigation into gene expression of MMP-13 in recovery will lead to new strategies for the treatment of liver cirrhosis.

Effects of pranlukast, a cysteinyl leukotriene antagonist, on bronchial responsiveness to methacholine in aspirin-intolerant asthmatics treated with corticosteroids.

Cysteinyl leukotrienes (cysLTs) are considered to be the most important mediator involved in the pathogenesis of aspirin-intolerant asthma (AIA). However, the role of cysLTs in the baseline condition of the pathophysiology of AIA when not exposed to non-steroidal antiinflammatory drugs (NSAIDs) as well as that in the pathophysiology of aspirin-tolerant asthma remains to be elucidated. Therefore, we evaluated the effect of pranlukast, a potent, selective cysLT receptor antagonist, on bronchial responsiveness to methacholine, a non-specific stimulus, in 7 well-controlled aspirin-intolerant asthmatics receiving oral or inhaled corticosteroid treatment. Pranlukast was orally administered at a dose of 225 mg twice daily to all patients for 4 weeks, and the methacholine challenge test was performed before and after pranlukast treatment. The methacholine provocative concentration producing a 20% fall in forced expiratory volume in 1 second (PC20-FEV1) was calculated as an index of bronchial hyperresponsiveness (BHR). The geometric mean values of PC20-FEV1 significantly (p = 0.028) increased from 0.34 mg/dl to 0.61 mg/dl after pranlukast treatment. No significant differences were observed in the baseline values of forced vital capacity (FVC) or FEV1 before and after pranlukast treatment. These findings suggest that antagonism of endogenous cysLT by pranlukast may be responsible for the improvement of BHR to methacholine.

Molecular mechanism of the reversibility of hepatic fibrosis: with special reference to the role of matrix metalloproteinases.

The participation of matrix metalloproteinases (MMP) and their specific inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMP), in both the formation and degradative recovery processes of liver fibrosis were mainly reviewed from the molecular biological aspect. Since authors first reported increased activity of interstitial collagenase in the early stage of hepatic fibrosis in rats induced by chronic CCl4 intoxication, in baboons fed alcohol chronically and in patients with alcoholic fibrosis, other investigators have also demonstrated increased activity biologically and histochemically. However, species-specific differences in response have been found and gene-level research on the rat model has not demonstrated increased mRNA transcription of collagenase. It has also been clarified that activated stellate cells can also produce matrix components. Very recently, authors observed the participation of interstitial collagenase in the recovery from experimental hepatic fibrosis by using polymerase chain reaction northern blotting and in situ hybridization. The in situ hybridization findings not only demonstrated the cells responsible for interstitial collagenase, but also suggested a great deal about the mechanism of recovery from fibrosis. Hepatic stellate cells are activated via the expression of c-myb and nuclear factor-kappaB (NFkappaB) which is induced by oxidative stress, and inhibited by antioxidant (1-alpha-tocopherol) and butylated hydroxytoluene. The activation mechanism is now being revealed. The relationship between the activation mechanism of stellate cells and the production and secretion of MMP and TIMP in the formation and recovery process of hepatic fibrosis should be investigated from the promoter gene level. This approach might help develop a new strategy for the treatment of liver fibrosis.

Interferon-inducible gene family 1-8U expression in colitis-associated colon cancer and severely inflamed mucosa in ulcerative colitis.

Persistent severe inflammation in colonic mucosa is thought to cause the development of colon cancer in patients with ulcerative colitis (UC). However, predisposing genetic abnormalities have not been identified in this sequence. Using differential display PCR, we isolated cDNA fragments corresponding to mRNAs that were differentially expressed in colitis-associated cancer tissues and mucosa with mild inflammation in the colon of five UC patients. This molecular screening approach identified 60 cDNA fragments, and we sequenced 34 fragments. One cDNA fragment, which is identical to IFN-inducible gene family 1-8U, was strongly expressed in all five UC-associated cancers. 1-8U was also expressed in sporadic colon cancer tissues and colon cancer cell lines, but not in normal mucosa. This gene was strongly expressed in severely inflamed colonic mucosa of UC without colitis-associated colon cancer, although 1-8U expression was not related to the extent and duration of the disease. However, 1-8U was expressed in the colonic mucosa of all patients with chronic, continuously severe inflammation. These results indicated that IFN-inducible gene family 1-8U expression in inflamed colonic mucosa might be used as a preferential marker of colitis-associated colon cancer in UC.

Activation of telomerase is induced by a natural antigen in allergen-specific memory T lymphocytes in bronchial asthma.

The function of the immune system is known to be dependent on the cellular differentiation and clonal expansion of allergen-specific lymphocytes. Telomerase, a ribonucleoprotein enzyme, is believed to be essential for the indefinite proliferation of human cells. To clarify whether telomerase is involved in the pathogenesis of immune diseases as well as of malignancies, we investigated the upregulation of telomerase activity in allergen-specific T lymphocytes. Upregulation of telomerase in allergen-sensitized lymphocytes was induced not only by artificial mitogenic stimulations but also by the natural antigen, house dust mite, which causes allergic diseases. Moreover, the upregulation of telomerase activity in memory T cells activated during allergen-specific immune responses might be associated with the enduring allergen-specific atopic propensity in asthmatics.

Pranlukast, a cysteinyl leukotriene antagonist, reduces serum eosinophil cationic protein levels in patients with asthma.

Cysteinyl leukotrienes (cysLTs) are considered to be important mediators involved in bronchial asthma and the ensuing eosinophilic inflammation. We evaluated the effects of pranlukast, a potent and selective cysLT receptor antagonist, on the clinical course and serum eosinophil cationic protein (ECP) levels of 10 asthmatic patients. A four-week administration of pranlukast increased the morning peak expiratory flow (PEF) (p = 0.007) and decreased as-needed beta 2-agonist use (p = 0.021). Changes in the morning PEF inversely correlated with those in the serum ECP levels (r = -0.80, p = 0.0057). These results suggest that cysLTs are important mediators involved in eosinophilic inflammation, a major pathophysiologic feature of bronchial asthma in humans.

Increased expression of tumor necrosis factor-alpha, interleukin-6, platelet-derived growth factor-B and granulocyte-macrophage colony-stimulating factor mRNA in cells of bronchoalveolar lavage fluids from patients with sarcoidosis.

Cytokines released from activated alveolar macrophages and T-lymphocytes affect the accumulation of monocyte-macrophage-lineage cells and therefore play an important role in the formation of sarcoid granuloma. Although it is likely that certain monokines and lymphokines are involved in the development of sarcoid granulomas, the evidence for this is not unequivocal. In an attempt to clear critical cytokines in the development and maintenance of sarcoid granuloma, we have measured the level of seven cytokine mRNA (TNF-alpha, IL-6, IL-8, TGF-beta, PDGF-B, IFN-gamma, and GM-CSF) in cells obtained by BAL from sarcoidosis patients and normal subjects. To detect cytokine mRNA, we employed a reverse transcription-polymerase chain reaction. We report that the levels of TNF-alpha, IL-6, PDGF-B and GM-CSF mRNA were significantly increased in BAL cells from the patients with pulmonary sarcoidosis compared to controls. No significant differences were observed in the mRNA expression of IL-8, TGF-beta and IFN-gamma. A significant correlation of the expression of the mRNA levels of seven cytokines in the same patients with sarcoidosis was observed between IL-8 and TNF-alpha, PDGF-B, and IL-6, IL-8 and IL-6 and TFN-alpha and PDGF-B and IL-8. This finding indicates that at least these four cytokines are involved in the cytokine network at the local alveolar site of chronic granulomatous inflammation. This study adds a report to the literature that supports a role for cytokine, TNF-alpha, IL-6, PDGF and GM-CSF in particular, in the promotion and maintenance of sarcoid granulomatous inflammation.

cAMP motifs regulating transcription in the aquaporin 2 gene.

Genomic clones including the 5' flanking regions of the AQP2 (aquaporin 2) gene were isolated, and the promoter region was examined by transiently transfecting a promoter-luciferase reporter fusion gene into renal cultured epithelial cells. An orientation specific promoter for the AQP2 gene was found within the proximal 3 kb of 5'-flanking region. Minimal basal promoter activity of the AQP2 gene was found within 198 bp upstream from the transcription start site by deletion analysis. Sequencing the transcriptionally active region revealed a typical TATA box, adenosine 3',5'-cyclic monophosphate (cAMP) responsive element (CRE) and three putative CCAAT boxes in the proximal 1.2-kb region. Significantly, a GATA motif, AP1, AP2, and SP1 transcriptional factor consensus sites were also found in this region. Exposure to cAMP-enhancing agents (1 nM vasopressin or 20 mM forskolin and 250 mM 3-isobutyl-1-methylxanthine) showed that these agents increased luciferase activity in a parallel fashion, suggesting that vasopressin-induced AQP2 gene transcription is mediated through increases in intracellular cAMP in at least one renal cell type, the LLC-PK1 cells. The mechanism of cAMP responsiveness of AQP2 gene transcription was further studied using a series of deletion mutants in renal epithelial cells and other cell types. The cAMP regulatory motifs were shown to exist in a 50-bp sequence between -340 and -290 (containing CRE) and a 65-bp sequence (containing an AP2 site) between -150 and the ATG start site in LLC-PK1 cells. In rat inner medullary collecting duct (IMCD) cells, the cAMP regulatory motifs also exist in a 50-bp sequence between -340 and -290 (containing CRE) and in a 10-bp sequence between -160 and -150 (containing an SP1 site). These separate regions may cooperate to confer full cAMP inducibility to the AQP2 gene in a cell-specific manner.

Effects of a PAF antagonist, Y-24180, on bronchial hyperresponsiveness in patients with asthma.

The involvement of platelet-activating factor (PAF) in bronchial hyperresponsiveness (BHR) in bronchial asthma has been controversial. To determine whether PAF is involved in BHR in humans, we carried out a randomized, double-blind, placebo-controlled, two-phase cross-over study on the effects of Y-24180, a potent, specific, orally active PAF receptor antagonist, on BHR to methacholine in patients with asthma. The subjects were 13 patients with extrinsic stable asthma. The provocative concentration of methacholine producing a 20% fall in FEV1 (PC20-FEV1) was measured as an index of BHR. Y-24180 (20 mg twice a day) or a placebo was orally administered for 2 wk, respectively. At the time of cross-over from the first treatment regimen to the second regimen, administration of the test drug was suspended for 2 wk. The methacholine challenge test was performed four times, before and after the first treatment period and before and after the second treatment period. Compared with the placebo, Y-24180 significantly (p = 0.005) improved the PC20-FEV1 value without carryover effect and period effect by analysis of variance. These results suggest that PAF is an important mediator involved in the BHR of bronchial asthma in humans.

Clinical usefulness of continuous administration of Nocardia rubra cell wall skeleton (N-CWS) in diffuse panbronchiolitis (DPB).

Eight patients with diffuse panbronchiolitis (DPB) who had repeated intractable airway infections were continuously treated with Nocardia rubra cell wall skeleton (N-CWS), a biological response modifier. As a result, subjective symptoms were reduced in 6 patients. Antibiotics therapy could be discontinued completely in two patients and the dose of antibiotics could be reduced considerably in two other patients. No adverse reactions in relation to N-CWS were observed. These results suggest that N-CWS is effective in treating erythromycin-resistant DPB.