Journal List > Allergy Asthma Immunol Res > v.6(6) > 1052448

Park: Role of Murine Asthma Model in Discovering Asthma Susceptible Genes
Asthma is a genetically complex disease associated with the familiar segregation of atopy and increased levels of total serum IgE.1 Asthma and atopy are also closely associated with increased bronchial hyperreactivity and elevated blood eosinophil count.2,3 These intermediate phenotypes are highly inheritable and the subject of asthma genetics research. The occurrence of asthma patients within families indicates the likely presence of a genetic component. Ge-nome-wide linkage studies, biologically plausible candidate gene approaches, and genome-wide association scans (GWAS), have been performed over the past 20 years to search for the genetic background of asthma. Recently, whole genome sequencing is applied to reveal the genes (or SNPs) related with the traits of asthma and subphenotypes. However, SNPs discovered by several GWASs have a limited ability to explain genetic effects for the development of asthma despite the significant number of enrolled subjects (more than 10,000). Imprecise disease phenotypes have been regarded as the factor related to the limitations of GWAS. Asthma should be classified into specific phenotypes with the consideration of environmental factors to overcome missing inheritability.4,5
Asthma is subgrouped into IgE-dependent Th2 dominant type, aspirin-exacerbated respiratory disease, occupational asthma, exercise-induced asthma, and menstruation-or obesity-associated asthma; it is further divided based on airway inflammatory patterns and immune responses.6,7 The mapping of susceptibility genes in asthmatics as a whole has been hampered by variability in sub-phenotypes, genetic heterogeneity across populations and uncontrolled environmental influences.8 To circumvent the complexity of genetic research in asthmatics, mouse model studies of allergic airway diseases have been applied to search for candidate genes related to the development of asthma.
In the present issue, Gergely Temesi et al.9 presented "Novel genes in Human Asthma Based on a Mouse Model of Allergic Airway Inflammation and Human Investigations". In the ovalbumin (OVA)-induced murine model of asthma, they applied microarray gene expression analysis at different time points after allergen challenges.10 In the late response of OVA-induced experimental asthma, they found more than thousand transcripts that showed statistical significances compared to the control. A total of 90 SNPs were genotyped, and the genotype distributions of 4 SNPs of 2 genes differed significantly: SCIN (rs2240572, rs2240571, rs3735222) and PPARGC1B (rs32588). They and ITLN1 (rs4656958), of which a SNP statistically borderline difference, were validated in induced sputum samples by measuring the protein levels of SCIN, PPARGC1B, and ITLN1. Three potentially novel asthma-associated genes were identified based on mouse experiments and human studies.
A Th2 dominant asthma model has been induced by intraperitoneal injection with OVA and aluminum hydroxide as adjuvant, followed by OVA intranasal challenges.11 The model shows airway hyperreactivity, goblet cell hyperplasia, pulmonary eosinophilia and increase of antigen-specific IgE. This model helps discover a considerable number of asthma candidate genes that include Th2 cytokines (IL-4, IL-15, IL-13, IL-9 and IL-25) and proinflammatory mediators (complements, arginase I, and arginase II).12,13 Even in this OVA model, inflammatory responses are very different depending on the time point.11 Asthma in humans is a chronic airway inflammation and the time point of the chronic asthma model represents a reflection of human asthma.
The results of Gergely Temesi et al indicated that the minor alleles of SCIN SNPs, rs2240572 (H61R) on exon 1 and rs3735222 on promoter region, had protective effects against asthma, and that these associations were more prominent when studying the female cohort separately. Consequently, the expression of certain genes, especially related female hormones, are highly likely dependent on gender difference. Allele carrying a 649G4C transversion in exon 4 of the PPARGC1B gene, resulting in an Ala-to-Pro (A203P) substitution, is significantly associated with familial breast cancer risk.14 Co-transfection assays demonstrated that nuclear receptors associated with the potent co-activator function of PPARGC1B are estrogen receptor alpha and glucocorticoid.15 Six week old female mice (used in many murine asthma models) are similar to the reproductive maturity of young human adult females. Thus, age factors should be considered in the data interpretation of this mice model.
Age dependency has been observed in several genetic association studies. When SNPs on ORM1-like 3 was analyzed according to the age of asthma onset, the statistical difference of rs 7216389 on 17q21 became more apparent in the age group <16 years in Caucasians and Koreans, whereas the statistical significance disappeared in the group >16 years.16 Early-onset asthma and the late-onset asthma may have a different immune-pathogenesis; therefore, mice less than 3 or 4 weeks old would be suitable for mice models to reflect childhood asthma. The protein scinderin encoded by the SCIN gene is an actin filament-severing and capping enzyme which rearranges the apical actin cap in airway goblet cells.17,18 SCIN is over-expressed following allergen challenge in mice19; however, the exact relationship of SCIN with Th2 immune response is unknown.
The gene discovered from one phenotype of asthma should be extended to the other kinds of asthma phenotypes using different animal models.20,21 Non-Th2 cytokine pathways (such as Th17 and inflammasome activation) underlie airway inflammation in specific subsets of asthma patients, especially non-eosinophilic inflammation.22,23 Well-characterized murine model mimics the pathophysiology of human allergic asthma in the interpretation of animal model data; however, it is not exactly the same. The development of murine models that reflect several sub-phenotypes of asthma remains an important goal for future human asthma studies.

Notes

There are no financial or other issues that might lead to conflict of interest.

References

1. Burrows B, Martinez FD, Halonen M, Barbee RA, Cline MG. Association of asthma with serum IgE levels and skin-test reactivity to allergens. N Engl J Med. 1989; 320:271–277.
2. Burrows B, Sears MR, Flannery EM, Herbison GP, Holdaway MD, Silva PA. Relation of the course of bronchial responsiveness from age 9 to age 15 to allergy. Am J Respir Crit Care Med. 1995; 152:1302–1308.
3. Bousquet J, Chanez P, Vignola AM, Lacoste JY, Michel FB. Eosinophil inflammation in asthma. Am J Respir Crit Care Med. 1994; 150:S33–S38.
4. Renz H, Autenrieth IB, Brandtzæg P, Cookson WO, Holgate S, von Mutius E, et al. Gene-environment interaction in chronic disease: a European Science Foundation Forward Look. J Allergy Clin Immunol. 2011; 128:S27–S49.
5. Zhang G, Khoo SK, Mäkelä MJ, Candelaria P, Hayden CM, von Hertzen L, et al. Maternal genetic variants of IL4/IL13 pathway genes on IgE with "Western or Eastern environments/lifestyles". Allergy Asthma Immunol Res. 2014; 6:350–356.
6. Wenzel SE. Asthma phenotypes: the evolution from clinical to molecular approaches. Nat Med. 2012; 18:716–725.
7. Kim SH, Sutherland ER, Gelfand EW. Is there a link between obesity and asthma? Allergy Asthma Immunol Res. 2014; 6:189–195.
8. Lee SH, Park JS, Park CS. The search for genetic variants and epigenetics related to asthma. Allergy Asthma Immunol Res. 2011; 3:236–244.
9. Temesi G, Virág V, Hadadi É, Ungvári I, Fodor LE, Bikov A, et al. Novel genes in human asthma based on a mouse model of allergic airway inflammation and human investigations. Allergy Asthma Immunol Res. 2014; 6:496–503.
10. Tölgyesi G, Molnár V, Semsei AF, Kiszel P, Ungvári I, Pócza P, et al. Gene expression profiling of experimental asthma reveals a possible role of paraoxonase-1 in the disease. Int Immunol. 2009; 21:967–975.
11. Ohkawara Y, Lei XF, Stämpfli MR, Marshall JS, Xing Z, Jordana M. Cytokine and eosinophil responses in the lung, peripheral blood, and bone marrow compartments in a murine model of allergen-induced airways inflammation. Am J Respir Cell Mol Biol. 1997; 16:510–520.
12. Karp CL, Grupe A, Schadt E, Ewart SL, Keane-Moore M, Cuomo PJ, et al. Identification of complement factor 5 as a susceptibility locus for experimental allergic asthma. Nat Immunol. 2000; 1:221–226.
13. Zimmermann N, King NE, Laporte J, Yang M, Mishra A, Pope SM, et al. Dissection of experimental asthma with DNA microarray analysis identifies arginase in asthma pathogenesis. J Clin Invest. 2003; 111:1863–1874.
14. Wirtenberger M, Tchatchou S, Hemminki K, Schmutzhard J, Sutter C, Schmutzler RK, et al. Associations of genetic variants in the estrogen receptor coactivators PPARGC1A, PPARGC1B and EP300 with familial breast cancer. Carcinogenesis. 2006; 27:2201–2208.
15. Kressler D, Schreiber SN, Knutti D, Kralli A. The PGC-1-related protein PERC is a selective coactivator of estrogen receptor alpha. J Biol Chem. 2002; 277:13918–13925.
16. Halapi E, Gudbjartsson DF, Jonsdottir GM, Bjornsdottir US, Thorleifsson G, Helgadottir H, et al. A sequence variant on 17q21 is associated with age at onset and severity of asthma. Eur J Hum Genet. 2010; 18:902–908.
17. Ehre C, Rossi AH, Abdullah LH, De Pestel K, Hill S, Olsen JC, et al. Barrier role of actin filaments in regulated mucin secretion from airway goblet cells. Am J Physiol Cell Physiol. 2005; 288:C46–C56.
18. Davis CW, Dickey BF. Regulated airway goblet cell mucin secretion. Annu Rev Physiol. 2008; 70:487–512.
19. Di Valentin E, Crahay C, Garbacki N, Hennuy B, Guéders M, Noël A, et al. New asthma biomarkers: lessons from murine models of acute and chronic asthma. Am J Physiol Lung Cell Mol Physiol. 2009; 296:L185–L197.
20. Blanchet MR, Gold MJ, McNagny KM. Mouse models to evaluate the function of genes associated with allergic airway disease. Curr Opin Allergy Clin Immunol. 2012; 12:467–474.
21. Maddur MS, Miossec P, Kaveri SV, Bayry J. Th17 cells: biology, pathogenesis of autoimmune and inflammatory diseases, and therapeutic strategies. Am J Pathol. 2012; 181:8–18.
22. Bhakta NR, Woodruff PG. Human asthma phenotypes: from the clinic, to cytokines, and back again. Immunol Rev. 2011; 242:220–232.
23. Allen IC, Jania CM, Wilson JE, Tekeppe EM, Hua X, Brickey WJ, et al. Analysis of NLRP3 in the development of allergic airway disease in mice. J Immunol. 2012; 188:2884–2893.
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Choon-Sik Park
https://orcid.org/http://orcid.org/0000-0003-2977-0255

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