Pathomechanisms underlying the psoriasiform skin disease in CD18 hypomorphic PL-J mice [Elektronische Ressource] / vorgelegt von Honglin Wang

Universität Ulm
Universitätsklinik für Dermatologie und Allergologie
Ärztliche Direktorin: Prof. Dr. Karin Scharffetter-Kochanek



Pathomechanisms underlying the psoriasiform skin
disease in CD18 hypomorphic PL/J mice



Dissertation zur Erlangung des Doktorgrades der Humanbiologie der Medizinischen
Fakultät der Universität Ulm







vorgelegt von
Honglin Wang
geb. in Nanjing, China

Ulm, 2006

TABLE OF CONTENTS
ABBREVIATIONS ....................................................................................................... 4
1. INTRODUCTION.............................................................................................. 7
1.1. Psoriasis........................................................................................................... 8
1.2.1. Clinical picture and histology of psoriasis .................................................. 9
1.2.2. Heredity of psoriasis .................................................................................. 9
1.2.3. The immunological synapse and psoriasis .............................................. 10
1.2.4. Animal models for psoriasis ......................................................................11
1.2.5. Immunological therapy in psoriasis.......................................................... 13
1.2. The CD18 hypomorphic PL/J mouse model of psoriasis................................ 15
1.2.1. Structure and function of CD18................................................................ 15
1.2.2. The psoriasiform skin disease in CD18 hypomorphic PL/J mice ............. 16
1.3. Role of macrophages in psoriasis................................................................... 18
1.3.1. Heterogeneity and activation of macrophages......................................... 18
1.3.2. Macrophages in psoriasis ........................................................................ 19
1.4. Role of TNF- α and MCP-1 in psoriasis........................................................... 20
1.4.1. TNF- α ...................................................................................................... 20
1.4.2. Anti-TNF- α therapy in psoriasis ............................................................... 21
1.4.3. MCP-1 21
1.4.4. MCP-1 in psoriasis................................................................................... 22
1.5. Role of T cell in psoriasis................................................................................ 23
1.5.1. T cell in psoriasis ..................................................................................... 23
1.5.2. Immune balance between regulatory T cells and effector T cells ............ 24
1.5.3. CD18 and regulatory T cells..................................................................... 24
1.6. Identification of modifier genes using a speed congenic approach ................ 25
1.6.1. Congenic strains...................................................................................... 25
1.6.2. ‘Speed’ congenics.................................................................................... 26
1.7. Aim of the work ............................................................................................... 28
2. MATERIALS AND METHODS ........................................................................ 29
2.1. Materials......................................................................................................... 29
2.1.1. Mice strains.............................................................................................. 29
2.1.2. Antibodies................................................................................................ 29
2.1.3. Chemicals 30
2.1.4. Buffers and Solutions............................................................................... 31
1 2.2. Methods.......................................................................................................... 33
2.2.1. Mice......................................................................................................... 33
2.2.2. In vivo depletion of macrophages ............................................................ 33
2.2.3. Immunohistochemical analysis................................................................ 34
2.2.4. Administration of etanercept .................................................................... 34
2.2.5. FACS analysis.......................................................................................... 35
2.2.6. Reverse-transcriptase PCR..................................................................... 35
2.2.7. ELISA....................................................................................................... 36
2.2.8. Intradermal injection of recombinant JE/MCP-1 and TNF- α and LPS ..... 36
2.2.9. Cell isolations........................................................................................... 37
2.2.10. Adhesion assays...................................................................................... 37
2.2.11. Suppression and Proliferation assays...................................................... 37
2.2.12. Adoptive transfer 38
2.2.13. Genotyping for “speed congenics”........................................................... 38
2.2.14. List of primers .......................................................................................... 39
2.2.15. Statistical analysis.................................................................................... 41
3. RESULTS....................................................................................................... 42
3.1. Activated macrophages are essential in a T cell-mediated murine psoriasis
model ....................................................................................................................... 42
3.1.1. Macrophages are markedly increased in lesional skin as well as in draining
hypolymph nodes of inflamed skin in affected CD18 mice...................................... 42
3.1.2. Macrophages are an important source of TNF- α in the lesional skin of
hypoaffected CD18 mice......................................................................................... 44
3.1.3. In addition to macrophages, infiltrating mast cells and endothelial cells are
hypoadditional sources of TNF- α in the lesional skin of CD18 PL/J mice............... 44
3.1.4. Blocking TNF- α by etanercept results in improvement of the psoriasiform
skin inflammation and is accompanied by reduced numbers of macrophages and
decreased expression of MHCII and TNF- α......................................................... 46
3.1.5. Administration of clodronate liposomes into murine skin depletes
+ + +macrophages, but has no significant effect on CD4 T cells, CD3 T cells, GR-1
+neutrophils, Langerhans cells and CD117 mast cells ......................................... 48
3.1.6. Improvement of the chronic psoriasiform skin inflammation with
concomitant decrease in TNF- α expression after depletion of skin macrophages50
3.1.7. Neutrophils do not contribute to the development of the chronic
hypopsoriasiform skin inflammation in CD18 PL/J mice 53
3.1.8. Both MCP-1 mRNA and protein levels are significantly enhanced in
hypopsoriatic lesions of CD18 mice ........................................................................ 56
3.1.9. Administration of murine recombinant JE/MCP-1 recruits macrophages to
hypothe skin of healthy CD18 mice, but fails to cause psoriasiform skin disease .. 56
3.1.10. Administration of LPS recruits and partially activates macrophages in the
skin and skin draining lymph nodes, while it fails to cause psoriasiform skin disease
hypoin healthy CD18 mice ...................................................................................... 59
2 3.1.11. Simultaneous injection of rJE/MCP-1 and rTNF- α results in the induction of
hypothe psoriasiform skin inflammation in healthy skin of CD18 PL/J mice ........... 64
3.2. Low expression of CD18 causes immune imbalance in a murine psoriasis
model ....................................................................................................................... 67
3.2.1. CD18 is required for efficient generation of natural T cells................... 67 reg
3.2.2. CD18 deficient T cells are dysfunctional in vitro and in vivo ................. 69 reg
3.2.3. Reduced CD18 expression impairs generation and activation of
antigen-experienced T cells............................................................................... 71 reg
hypo3.2.4. Reduced expression of TGF- β1 by CD18 T cells is responsible for the reg
development of psoriasiform skin disease ........................................................... 77
+ – hypo 3.2.5. CD4 CD25 T cells of CD18 mice exhibit early proliferative responsesresp
...................................................................................................................81
3.2.6. Low CD18 expression enhances the generation of antigen-experienced T
cells ..................................................................................................................81
+ - hypo3.2.7. CD4 CD25 T cells of affected CD18 mice are pathogenic in the
development of th