The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model
Atopic dermatitis (AD) is a complex, often lifelong allergic disease affecting around 10 % of both dogs and humans. The hallmark symptom is severe pruritus, causing a lowered quality of life. Mast cells (MCs) are known to play an important part of the immunopathogenesis, promoting a faulty T help...
| Autor principal: | |
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2014
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/6630/ |
| _version_ | 1855571045220614144 |
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| author | Andersson, Sofie |
| author_browse | Andersson, Sofie |
| author_facet | Andersson, Sofie |
| author_sort | Andersson, Sofie |
| collection | Epsilon Archive for Student Projects |
| description | Atopic dermatitis (AD) is a complex, often lifelong allergic disease affecting around 10 % of both
dogs and humans. The hallmark symptom is severe pruritus, causing a lowered quality of life. Mast
cells (MCs) are known to play an important part of the immunopathogenesis, promoting a faulty T
helper cell type 2 (Th-2) response which follows by a production of specific immunoglobulin E
(IgE) antibodies towards environmental allergens (Ag). To further investigate the role of MCs and
its mediators in the progression of AD, a low-calcemic vitamin D3 analog (MC903) was used to
induce AD-like symptoms locally on the ears of two different knock-out (KO) mouse strains. The
first strain was Wsh-/- mice deficient in MCs. The second strain was mice deficient in mouse mast
cell protease 4 (mMCP-4-/-), a homolog to the human and canine MC chymase (MCC).
The hypothesis was to observe an increase in inflammatory parameters following MC903-treatment,
such as migration of inflammatory cells, higher amount of inflammatory mediators and clinically
observed ear thickening. Thereby, MC903 would be proven to induce a functioning AD animal
model. The results showed that daily topical MC903 application on the left ear induced changes
mimicking AD macroscopically, microscopically and biochemically, including a Th-2 response
represented by associated cytokines. No changes were seen in the vehicle-treated ears (treated with
ethanol) used as an internal control.
The epithelial cell-derived thymic stromal lymphopoietin (TSLP) appeared to be an important
cytokine in promoting the skin inflammation since the amount of TSLP was markedly high locally
in the MC903-treated ears. In MC-deficient mice, TSLP-levels were significantly lower, thus
implicating a central role of MCs in this model. Although the presence of MCs caused higher levels
of both TSLP and interleukin 33 (IL-33) after MC903-treatment, the clinical appearance in Wsh+/-
mice was milder compared to mice lacking MCs. This indicates that MCs do promote the AD-like
skin inflammation caused by MC903, but at the same time prohibit the inflammation from being too
excessive.
The results from a small in vitro study performed as a part of this study, proved that MC903 also
activates MCs directly to degranulate. The MCC homolog mMCP-4 did on the contrary only
contribute to the lowering of IL-33 levels, most likely through cleavage of the cytokine by mMCP-
4, therefore no apparent role of MCC could be observed. In the cleavage study of TSLP, a more
rapid cleavage of TSLP was mediated by tryptase than chymase. Thus, as a continuation of this
study, the investigation of the role of tryptase in the MC903-induced AD-model would be of high
interest.
In conclusion, MC903 application induced an AD-like local inflammation, thus showing that the
method provides a functioning AD-model. MCs contribute to disease progression through cytokine
production, but have at the same time a limiting role in the course of inflammation. |
| format | Second cycle, A2E |
| id | RepoSLU6630 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2014 |
| publishDateSort | 2014 |
| record_format | eprints |
| spelling | RepoSLU66302015-01-01T00:15:02Z https://stud.epsilon.slu.se/6630/ The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model Andersson, Sofie Animal physiology and biochemistry Animal diseases Atopic dermatitis (AD) is a complex, often lifelong allergic disease affecting around 10 % of both dogs and humans. The hallmark symptom is severe pruritus, causing a lowered quality of life. Mast cells (MCs) are known to play an important part of the immunopathogenesis, promoting a faulty T helper cell type 2 (Th-2) response which follows by a production of specific immunoglobulin E (IgE) antibodies towards environmental allergens (Ag). To further investigate the role of MCs and its mediators in the progression of AD, a low-calcemic vitamin D3 analog (MC903) was used to induce AD-like symptoms locally on the ears of two different knock-out (KO) mouse strains. The first strain was Wsh-/- mice deficient in MCs. The second strain was mice deficient in mouse mast cell protease 4 (mMCP-4-/-), a homolog to the human and canine MC chymase (MCC). The hypothesis was to observe an increase in inflammatory parameters following MC903-treatment, such as migration of inflammatory cells, higher amount of inflammatory mediators and clinically observed ear thickening. Thereby, MC903 would be proven to induce a functioning AD animal model. The results showed that daily topical MC903 application on the left ear induced changes mimicking AD macroscopically, microscopically and biochemically, including a Th-2 response represented by associated cytokines. No changes were seen in the vehicle-treated ears (treated with ethanol) used as an internal control. The epithelial cell-derived thymic stromal lymphopoietin (TSLP) appeared to be an important cytokine in promoting the skin inflammation since the amount of TSLP was markedly high locally in the MC903-treated ears. In MC-deficient mice, TSLP-levels were significantly lower, thus implicating a central role of MCs in this model. Although the presence of MCs caused higher levels of both TSLP and interleukin 33 (IL-33) after MC903-treatment, the clinical appearance in Wsh+/- mice was milder compared to mice lacking MCs. This indicates that MCs do promote the AD-like skin inflammation caused by MC903, but at the same time prohibit the inflammation from being too excessive. The results from a small in vitro study performed as a part of this study, proved that MC903 also activates MCs directly to degranulate. The MCC homolog mMCP-4 did on the contrary only contribute to the lowering of IL-33 levels, most likely through cleavage of the cytokine by mMCP- 4, therefore no apparent role of MCC could be observed. In the cleavage study of TSLP, a more rapid cleavage of TSLP was mediated by tryptase than chymase. Thus, as a continuation of this study, the investigation of the role of tryptase in the MC903-induced AD-model would be of high interest. In conclusion, MC903 application induced an AD-like local inflammation, thus showing that the method provides a functioning AD-model. MCs contribute to disease progression through cytokine production, but have at the same time a limiting role in the course of inflammation. Atopisk dermatit (AD) är en komplex och ofta livslång allergisk sjukdom som drabbar ca 10 % av alla människor och hundar. Svår klåda kännetecknar sjukdomen, vilket medför en försämrad livskvalitet för drabbade individer. Det är känt att mastceller (MC) är viktiga i immunopatogenesen, då de bidrar till att skapa ett onormalt immunsvar med typ 2 T-hjälparceller (Th-2). Dessa är förknippade med produktionen av immunoglobulin E (IgE) antikroppar mot allergen i omgivningen. I detta försök användes en vitamin D3-analog (MC903) för att inducera AD-liknande symtom lokalt på öronen, tillhörande två olika knock-out (KO) musstammar. Detta gjordes för att ytterligare undersöka hur MC och dess mediatorer kan bidra i sjukdomsutvecklingen av AD. Den ena KO musstammen (Wsh-/-) saknar MC och den andra KO musstammen saknar mastcellsproteas 4 (mMCP-4-/-), en mushomolog till mastcellsproteaset kymas (MCC) hos människa och hund. Hypotesen i försöket var att lokalbehandling med MC903 skulle öka de inflammationsparametrar som valts att studera i studien (klinisk sjukdomsutveckling, migration av inflammatoriska celler, mängd av inflammatoriska mediatorer), vilket skulle bevisa att MC903 skapar en funktionell ADmodell. Resultatet i studien visade att en upprepad applikation av MC903 på ena örat inducerade förändringar som liknar dem som ses vid naturligt förekommande AD, både makroskopiskt och mikroskopiskt samt biokemiskt. Inga förändringar sågs i det andra örat som behandlades med vehikel (etanol) och användes som en intern kontroll. TSLP (thymic stromal lymphopoietin), ett cytokin som främst produceras av epitelceller, bedömdes i försöket ha en viktig funktion i utvecklingen av den AD-liknande hudinflammationen då de MC903-behandlade öronen innehöll mycket stora mängder TSLP. Hos mössen som saknade MC var TSLP-nivåerna signifikant lägre, vilket tyder på en central roll för MC i denna modell. Även om MC903-behandlingen inducerade högre cytokinnivåer (bl.a. TSLP, interleukin 33 (IL-33)), var den kliniska bilden mildare hos Wsh+/- möss jämfört med Wsh-/- möss (som saknar MC). Detta indikerar en drivande roll för MC i den AD-liknande hudinflammationen som uppstår efter applikation av MC903, samtidigt som MC har en begränsande roll för inflammationen. En liten in vitro studie som utfördes under detta projekt, bevisade att MC903 även kan aktivera MC direkt till degranulering. Ingen tydlig roll för mMCP-4 i denna musmodell kunde påvisas, då det enbart minskade nivåerna av IL-33, troligen via klyvning av cytokinet. Klyvningsstudien av TSLP visade en snabbare nedbrytning av TSLP med tryptas än med kymas. Som en fortsättning på denna studie vore det därför intressant att närmre undersöka rollen av tryptas i den MC903-inducerade AD-modellen. Sammanfattningsvis gav en upprepad applikation av MC903 uppkomst till en AD-liknande, lokal hudinflammation vilket visar att metoden fungerar som en AD-modell. MC bidrar i sjukdomsutvecklingen genom att höja cytokin-nivåerna, men förhindrar samtidigt en överdriven inflammation. 2014-08-04 Second cycle, A2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/6630/1/Andersson_S_140414.pdf Andersson, Sofie, 2015. The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model. Second cycle, A2E. Uppsala: (VH) > Dept. of Biomedical Sciences and Veterinary Public Health (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-713.html> urn:nbn:se:slu:epsilon-s-3688 eng |
| spellingShingle | Animal physiology and biochemistry Animal diseases Andersson, Sofie The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title | The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title_full | The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title_fullStr | The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title_full_unstemmed | The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title_short | The role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| title_sort | role of mast cells and mast cell mediators in the development of atopic dermatitis in a mouse model |
| topic | Animal physiology and biochemistry Animal diseases |
| url | https://stud.epsilon.slu.se/6630/ https://stud.epsilon.slu.se/6630/ |