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No description available.

No description available.

The multigene family of Ca2+-binding S100 proteins comprises 22 members that have various important intra- and extracellular roles. The three inflammation-associated members of this family???S100A8, S100A9 and S100A12 (collectively termed &quotcalgranulins&quot)???are constitutive neutrophil and monocyte proteins also expressed by macrophages within acute and chronic inflammatory lesions, but not in tissue macrophages. They are expressed in human/murine wounds and by appropriately activated macrophages, microvascular endothelial cells and keratinocytes in vitro. The &quot calgranulins&quot are implicated in leukocyte activation/deactivation, fatty acid transport, leukocyte/fibroblast chemotaxis, transmigration and adhesion, embryogenesis, wound healing, protection against oxidants and antibacterial defence. Chapter 3 of this thesis explores growth-factor- and cytokine-mediated regulation and expression of S100A8 and S100A9 in fibroblasts, and demonstrates spatio-temporal expression of S100A8 in rat dermal wounds. Fibroblasts are stromal resident cells with important regulatory immune-inflammatory functions in wound healing, tissue remodelling and fibrosis. Fibroblast migration, proliferation, differentiation and their synthetic repertoire are modulated by various factors including extracellular matrix components, growth factors, prostaglandins, reactive oxygen species and cytokines. Fibroblast growth factor-2 (FGF-2), interleukin-1?(IL-1? and platelet-derived growth factor (PDGF) are potent fibroblast mitogens; PDGF and transforming growth factor-? (TGF-? are fibroblast chemoattractants. FGF-2 and IL-1?promote fibroblast proliferation, whereas TGF-?promotes myofibroblast differentiation and collagen production. Lipopolysaccharide (LPS), interferon ?(IFN?, tumour-necrosis factor ? (TNF?, TGF-?and PDGF did not induce the S100A8 gene in fibroblasts whereas FGF-2 (25 ng/ml) maximally induced mRNA 12 hr. after stimulation and this declined over 36 hr. The FGF-2 response was strongly enhanced and prolonged by optimal levels of heparin (1-10 IU/ml), maximally at 18 hr. post-stimulation. FGF-2/heparin-induced responses depended on cell-cell contact in vitro. IL-1?(10 U/ml) alone, or in synergy with FGF-2/heparin strongly induced the gene in 3T3 and primary fibroblasts. Dexamethasone (10???6 M) enhanced LPS- and FGF-2/-IL-1?induced responses. S100A9 mRNA was not induced by any of these mediators. Induction of S100A8 in the absence of S100A9 was confirmed in primary fibroblast-like cells by real-time reverse-transcriptase polymerase chain-reaction. FGF-2-heparin- and IL-1?induced mRNA expression depended on de-novo protein synthesis and was partially mediated by the mitogenactivated protein kinase pathway of activation. Preliminary promoter deletion analyses indicated that FGF-2-responsive elements in the gene promoter were distinct from those responsive to IL-1? TGF-?(2 ng/ml) significantly suppressed gene induction mediated by FGF-2 ?heparin/LPS/dexamethasone, but not by IL-1? TGF-?may compromise mRNA stability. Protein levels in FGF-2-heparin-IL-1?stimulated fibroblasts correlated well with mRNA levels and expression was mainly cytoplasmic. Immunohistochemistry indicated S100A8 associated with keratinocytes, neutrophils, macrophage-like cells and some hair follicles in wounded rat skin. Rat wounds also contained numerous S100A8- positive fibroblast-like cells 2 and 4 days post-injury; numbers declined by 7 days. Upregulation of S100A8 by FGF-2/IL-1? down-regulation by TGF-? and time-dependent expression of S100A8 in wound fibroblasts suggest a role in fibroblast differentiation at sites of inflammation and repair. Intracellular fibroblast-derived S100A8 may also regulate intracellular redox equilibrium and antioxidant defence. Atherosclerosis is a progressive chronic disease with complex aetiology and pathogenesis. S100A1 and S100B are associated with dendritic cells and lymphocytes in experimental rodent and human atherosclerotic lesions. Monocytes and macrophages in plaques of ApoE???/??? mice express S100A9 but not S100A8. Myeloperoxidase and HOClmediated oxidative mechanisms are fundamental in the pathogenesis of atherosclerosis and S100A8 is exquisitely sensitive to HOCl oxidation which generates sulphinamide bonds, novel non-reducible cysteine-lysine covalent bonds. Chapter 4 of this thesis presents novel evidence that, in contrast to the murine ApoE???/??? model, the three human &quot calgranulins&quot were expressed in human atherosclerotic plaques, but not in normal arteries. High levels of S100A8, S100A9 and S100A12 were evident in macrophages and foam cells. Some neovessels were anti-S100A8-/anti-S100A9-immunoreactive; S100A9 staining was also evident on the extracellular matrix. Patterns of expression of S100A8, S100A9 and S100A12 were overlapping in serial sections, except that only smooth muscle cells were S100A12-positive. S100A8 and S100A9 mRNA were also expressed by macrophages, foam cells and endothelial cells, indicating gene up-regulation rather than passive protein uptake. Western blotting of plaque extracts revealed monomeric S100A8, S100A9 and S100A12 and larger complexes. Some were resistant to reduction, suggesting non-disulfide covalent cross-linking, possibly via sulphinamide bonds. Stable S100A8-S100A9 complexes were also detected after immunoaffinity purification. In an in-vitro system, molar ratios of HOCl of &gt1 generated stable complexes of S100A8 and S100A9 whereas ~800 and ~100-fold excess HOCl oxidises apolipoprotein B-100 and BSA, respectively. S100A8 and S100A9 protected low-density lipoprotein (LDL) against HOCl oxidation in a thiol-independent manner. Because HOCl-oxidised S100s did not contain epitopes recognised by an antibody used to detect HOCl-oxidised proteins in plaque, levels of oxidised proteins in plaque are likely to be significantly greater than described. S100A8 and S100A9 may protect LDL by functioning as HOCl-scavengers. However, chronic oxidative cross-linking of S100A8 and S100A9 with other proteins and extracellular matrix components may contribute to plaque pathogenesis. These studies support key roles for the &quot calgranulins&quot in chronic inflammation, wound healing and atherogenesis possibly by regulating cellular differentiation, activation and modulation of redox-dependent mechanisms.

The multigene family of Ca2+-binding S100 proteins comprises 22 members that have various important intra- and extracellular roles. The three inflammation-associated members of this family???S100A8, S100A9 and S100A12 (collectively termed &quotcalgranulins&quot)???are constitutive neutrophil and monocyte proteins also expressed by macrophages within acute and chronic inflammatory lesions, but not in tissue macrophages. They are expressed in human/murine wounds and by appropriately activated macrophages, microvascular endothelial cells and keratinocytes in vitro. The &quot calgranulins&quot are implicated in leukocyte activation/deactivation, fatty acid transport, leukocyte/fibroblast chemotaxis, transmigration and adhesion, embryogenesis, wound healing, protection against oxidants and antibacterial defence. Chapter 3 of this thesis explores growth-factor- and cytokine-mediated regulation and expression of S100A8 and S100A9 in fibroblasts, and demonstrates spatio-temporal expression of S100A8 in rat dermal wounds. Fibroblasts are stromal resident cells with important regulatory immune-inflammatory functions in wound healing, tissue remodelling and fibrosis. Fibroblast migration, proliferation, differentiation and their synthetic repertoire are modulated by various factors including extracellular matrix components, growth factors, prostaglandins, reactive oxygen species and cytokines. Fibroblast growth factor-2 (FGF-2), interleukin-1?(IL-1? and platelet-derived growth factor (PDGF) are potent fibroblast mitogens; PDGF and transforming growth factor-? (TGF-? are fibroblast chemoattractants. FGF-2 and IL-1?promote fibroblast proliferation, whereas TGF-?promotes myofibroblast differentiation and collagen production. Lipopolysaccharide (LPS), interferon ?(IFN?, tumour-necrosis factor ? (TNF?, TGF-?and PDGF did not induce the S100A8 gene in fibroblasts whereas FGF-2 (25 ng/ml) maximally induced mRNA 12 hr. after stimulation and this declined over 36 hr. The FGF-2 response was strongly enhanced and prolonged by optimal levels of heparin (1-10 IU/ml), maximally at 18 hr. post-stimulation. FGF-2/heparin-induced responses depended on cell-cell contact in vitro. IL-1?(10 U/ml) alone, or in synergy with FGF-2/heparin strongly induced the gene in 3T3 and primary fibroblasts. Dexamethasone (10???6 M) enhanced LPS- and FGF-2/-IL-1?induced responses. S100A9 mRNA was not induced by any of these mediators. Induction of S100A8 in the absence of S100A9 was confirmed in primary fibroblast-like cells by real-time reverse-transcriptase polymerase chain-reaction. FGF-2-heparin- and IL-1?induced mRNA expression depended on de-novo protein synthesis and was partially mediated by the mitogenactivated protein kinase pathway of activation. Preliminary promoter deletion analyses indicated that FGF-2-responsive elements in the gene promoter were distinct from those responsive to IL-1? TGF-?(2 ng/ml) significantly suppressed gene induction mediated by FGF-2 ?heparin/LPS/dexamethasone, but not by IL-1? TGF-?may compromise mRNA stability. Protein levels in FGF-2-heparin-IL-1?stimulated fibroblasts correlated well with mRNA levels and expression was mainly cytoplasmic. Immunohistochemistry indicated S100A8 associated with keratinocytes, neutrophils, macrophage-like cells and some hair follicles in wounded rat skin. Rat wounds also contained numerous S100A8- positive fibroblast-like cells 2 and 4 days post-injury; numbers declined by 7 days. Upregulation of S100A8 by FGF-2/IL-1? down-regulation by TGF-? and time-dependent expression of S100A8 in wound fibroblasts suggest a role in fibroblast differentiation at sites of inflammation and repair. Intracellular fibroblast-derived S100A8 may also regulate intracellular redox equilibrium and antioxidant defence. Atherosclerosis is a progressive chronic disease with complex aetiology and pathogenesis. S100A1 and S100B are associated with dendritic cells and lymphocytes in experimental rodent and human atherosclerotic lesions. Monocytes and macrophages in plaques of ApoE???/??? mice express S100A9 but not S100A8. Myeloperoxidase and HOClmediated oxidative mechanisms are fundamental in the pathogenesis of atherosclerosis and S100A8 is exquisitely sensitive to HOCl oxidation which generates sulphinamide bonds, novel non-reducible cysteine-lysine covalent bonds. Chapter 4 of this thesis presents novel evidence that, in contrast to the murine ApoE???/??? model, the three human &quot calgranulins&quot were expressed in human atherosclerotic plaques, but not in normal arteries. High levels of S100A8, S100A9 and S100A12 were evident in macrophages and foam cells. Some neovessels were anti-S100A8-/anti-S100A9-immunoreactive; S100A9 staining was also evident on the extracellular matrix. Patterns of expression of S100A8, S100A9 and S100A12 were overlapping in serial sections, except that only smooth muscle cells were S100A12-positive. S100A8 and S100A9 mRNA were also expressed by macrophages, foam cells and endothelial cells, indicating gene up-regulation rather than passive protein uptake. Western blotting of plaque extracts revealed monomeric S100A8, S100A9 and S100A12 and larger complexes. Some were resistant to reduction, suggesting non-disulfide covalent cross-linking, possibly via sulphinamide bonds. Stable S100A8-S100A9 complexes were also detected after immunoaffinity purification. In an in-vitro system, molar ratios of HOCl of &gt1 generated stable complexes of S100A8 and S100A9 whereas ~800 and ~100-fold excess HOCl oxidises apolipoprotein B-100 and BSA, respectively. S100A8 and S100A9 protected low-density lipoprotein (LDL) against HOCl oxidation in a thiol-independent manner. Because HOCl-oxidised S100s did not contain epitopes recognised by an antibody used to detect HOCl-oxidised proteins in plaque, levels of oxidised proteins in plaque are likely to be significantly greater than described. S100A8 and S100A9 may protect LDL by functioning as HOCl-scavengers. However, chronic oxidative cross-linking of S100A8 and S100A9 with other proteins and extracellular matrix components may contribute to plaque pathogenesis. These studies support key roles for the &quot calgranulins&quot in chronic inflammation, wound healing and atherogenesis possibly by regulating cellular differentiation, activation and modulation of redox-dependent mechanisms.

The multigene family of Ca2+-binding S100 proteins comprises 22 members that have various important intra- and extracellular roles. The three inflammation-associated members of this family???S100A8, S100A9 and S100A12 (collectively termed &quotcalgranulins&quot)???are constitutive neutrophil and monocyte proteins also expressed by macrophages within acute and chronic inflammatory lesions, but not in tissue macrophages. They are expressed in human/murine wounds and by appropriately activated macrophages, microvascular endothelial cells and keratinocytes in vitro. The &quot calgranulins&quot are implicated in leukocyte activation/deactivation, fatty acid transport, leukocyte/fibroblast chemotaxis, transmigration and adhesion, embryogenesis, wound healing, protection against oxidants and antibacterial defence. Chapter 3 of this thesis explores growth-factor- and cytokine-mediated regulation and expression of S100A8 and S100A9 in fibroblasts, and demonstrates spatio-temporal expression of S100A8 in rat dermal wounds. Fibroblasts are stromal resident cells with important regulatory immune-inflammatory functions in wound healing, tissue remodelling and fibrosis. Fibroblast migration, proliferation, differentiation and their synthetic repertoire are modulated by various factors including extracellular matrix components, growth factors, prostaglandins, reactive oxygen species and cytokines. Fibroblast growth factor-2 (FGF-2), interleukin-1?(IL-1? and platelet-derived growth factor (PDGF) are potent fibroblast mitogens; PDGF and transforming growth factor-? (TGF-? are fibroblast chemoattractants. FGF-2 and IL-1?promote fibroblast proliferation, whereas TGF-?promotes myofibroblast differentiation and collagen production. Lipopolysaccharide (LPS), interferon ?(IFN?, tumour-necrosis factor ? (TNF?, TGF-?and PDGF did not induce the S100A8 gene in fibroblasts whereas FGF-2 (25 ng/ml) maximally induced mRNA 12 hr. after stimulation and this declined over 36 hr. The FGF-2 response was strongly enhanced and prolonged by optimal levels of heparin (1-10 IU/ml), maximally at 18 hr. post-stimulation. FGF-2/heparin-induced responses depended on cell-cell contact in vitro. IL-1?(10 U/ml) alone, or in synergy with FGF-2/heparin strongly induced the gene in 3T3 and primary fibroblasts. Dexamethasone (10???6 M) enhanced LPS- and FGF-2/-IL-1?induced responses. S100A9 mRNA was not induced by any of these mediators. Induction of S100A8 in the absence of S100A9 was confirmed in primary fibroblast-like cells by real-time reverse-transcriptase polymerase chain-reaction. FGF-2-heparin- and IL-1?induced mRNA expression depended on de-novo protein synthesis and was partially mediated by the mitogenactivated protein kinase pathway of activation. Preliminary promoter deletion analyses indicated that FGF-2-responsive elements in the gene promoter were distinct from those responsive to IL-1? TGF-?(2 ng/ml) significantly suppressed gene induction mediated by FGF-2 ?heparin/LPS/dexamethasone, but not by IL-1? TGF-?may compromise mRNA stability. Protein levels in FGF-2-heparin-IL-1?stimulated fibroblasts correlated well with mRNA levels and expression was mainly cytoplasmic. Immunohistochemistry indicated S100A8 associated with keratinocytes, neutrophils, macrophage-like cells and some hair follicles in wounded rat skin. Rat wounds also contained numerous S100A8- positive fibroblast-like cells 2 and 4 days post-injury; numbers declined by 7 days. Upregulation of S100A8 by FGF-2/IL-1? down-regulation by TGF-? and time-dependent expression of S100A8 in wound fibroblasts suggest a role in fibroblast differentiation at sites of inflammation and repair. Intracellular fibroblast-derived S100A8 may also regulate intracellular redox equilibrium and antioxidant defence. Atherosclerosis is a progressive chronic disease with complex aetiology and pathogenesis. S100A1 and S100B are associated with dendritic cells and lymphocytes in experimental rodent and human atherosclerotic lesions. Monocytes and macrophages in plaques of ApoE???/??? mice express S100A9 but not S100A8. Myeloperoxidase and HOClmediated oxidative mechanisms are fundamental in the pathogenesis of atherosclerosis and S100A8 is exquisitely sensitive to HOCl oxidation which generates sulphinamide bonds, novel non-reducible cysteine-lysine covalent bonds. Chapter 4 of this thesis presents novel evidence that, in contrast to the murine ApoE???/??? model, the three human &quot calgranulins&quot were expressed in human atherosclerotic plaques, but not in normal arteries. High levels of S100A8, S100A9 and S100A12 were evident in macrophages and foam cells. Some neovessels were anti-S100A8-/anti-S100A9-immunoreactive; S100A9 staining was also evident on the extracellular matrix. Patterns of expression of S100A8, S100A9 and S100A12 were overlapping in serial sections, except that only smooth muscle cells were S100A12-positive. S100A8 and S100A9 mRNA were also expressed by macrophages, foam cells and endothelial cells, indicating gene up-regulation rather than passive protein uptake. Western blotting of plaque extracts revealed monomeric S100A8, S100A9 and S100A12 and larger complexes. Some were resistant to reduction, suggesting non-disulfide covalent cross-linking, possibly via sulphinamide bonds. Stable S100A8-S100A9 complexes were also detected after immunoaffinity purification. In an in-vitro system, molar ratios of HOCl of &gt1 generated stable complexes of S100A8 and S100A9 whereas ~800 and ~100-fold excess HOCl oxidises apolipoprotein B-100 and BSA, respectively. S100A8 and S100A9 protected low-density lipoprotein (LDL) against HOCl oxidation in a thiol-independent manner. Because HOCl-oxidised S100s did not contain epitopes recognised by an antibody used to detect HOCl-oxidised proteins in plaque, levels of oxidised proteins in plaque are likely to be significantly greater than described. S100A8 and S100A9 may protect LDL by functioning as HOCl-scavengers. However, chronic oxidative cross-linking of S100A8 and S100A9 with other proteins and extracellular matrix components may contribute to plaque pathogenesis. These studies support key roles for the &quot calgranulins&quot in chronic inflammation, wound healing and atherogenesis possibly by regulating cellular differentiation, activation and modulation of redox-dependent mechanisms.

S100B is a member of the S100 calcium binding protein family and is highly expressed within astrocytes in the brain. Elevated levels of S100B are associated with brain and central nervous system disorders, due to the breakdown of the blood brain barrier. Therefore S100B is routinely used as a marker of disease. Traditionally S100B was thought only as a cell breakdown product but increasing evidence suggests that it may play a role in exacerbating inflammation, however this role is not clear. S100B is known to be present within the eye but its role in retinal inflammation has not been investigated. The aim of this project was therefore to examine the role of S100B using the animal model experimental autoimmune uveoretinitis (EAU). This is a well-established model for the sight-threatening human condition posterior endogenous uveoretinitis. In this disease model an autoimmune response is induced leading to retinal inflammation. Using S100B knockout mice, I have shown a significantly reduced level of disease, as determined by clinical and histological grading. Real-time PCR array analysis of diseased matched retinas indicated down regulation of cytokines and chemokines in S100B knockout mice. In vitro experiments on a macrophage cell line confirmed S100B to have a pro-inflammatory effect on macrophages, the main effector cell in EAU, with up-regulation of cytokine and chemokine expression. In particular IL-1β, CCR1 and CCL22 showed a marked increase in gene expression in response to S100B which was confirmed by real-time PCR. Increased protein production of IL-1β (pro-form), CCR1 and CCL22 was also confirmed. S100B inhibited activation of T cells separated from spleens, as shown by reduced CD25+ expression and IL-2 production. IFN-γ and IL-17 production however was not affected. CCL2 and IL-6 are main inflammatory mediators produced by retinal pigment epithelial cells which are known to be elevated during retinal inflammation. S100B promoted CCL2 and IL-6 production in retinal pigment epithelial cells at different concentrations. The work carried out in this thesis provides additional understanding of the actions of extracellular S100B on immune system cells and its potential role in posterior uveitis.

The multigene family of Ca2+-binding S100 proteins comprises 22 members that have various important intra- and extracellular roles. The three inflammation-associated members of this family???S100A8, S100A9 and S100A12 (collectively termed &quotcalgranulins&quot)???are constitutive neutrophil and monocyte proteins also expressed by macrophages within acute and chronic inflammatory lesions, but not in tissue macrophages. They are expressed in human/murine wounds and by appropriately activated macrophages, microvascular endothelial cells and keratinocytes in vitro. The &quot calgranulins&quot are implicated in leukocyte activation/deactivation, fatty acid transport, leukocyte/fibroblast chemotaxis, transmigration and adhesion, embryogenesis, wound healing, protection against oxidants and antibacterial defence. Chapter 3 of this thesis explores growth-factor- and cytokine-mediated regulation and expression of S100A8 and S100A9 in fibroblasts, and demonstrates spatio-temporal expression of S100A8 in rat dermal wounds. Fibroblasts are stromal resident cells with important regulatory immune-inflammatory functions in wound healing, tissue remodelling and fibrosis. Fibroblast migration, proliferation, differentiation and their synthetic repertoire are modulated by various factors including extracellular matrix components, growth factors, prostaglandins, reactive oxygen species and cytokines. Fibroblast growth factor-2 (FGF-2), interleukin-1?(IL-1? and platelet-derived growth factor (PDGF) are potent fibroblast mitogens; PDGF and transforming growth factor-? (TGF-? are fibroblast chemoattractants. FGF-2 and IL-1?promote fibroblast proliferation, whereas TGF-?promotes myofibroblast differentiation and collagen production. Lipopolysaccharide (LPS), interferon ?(IFN?, tumour-necrosis factor ? (TNF?, TGF-?and PDGF did not induce the S100A8 gene in fibroblasts whereas FGF-2 (25 ng/ml) maximally induced mRNA 12 hr. after stimulation and this declined over 36 hr. The FGF-2 response was strongly enhanced and prolonged by optimal levels of heparin (1-10 IU/ml), maximally at 18 hr. post-stimulation. FGF-2/heparin-induced responses depended on cell-cell contact in vitro. IL-1?(10 U/ml) alone, or in synergy with FGF-2/heparin strongly induced the gene in 3T3 and primary fibroblasts. Dexamethasone (10???6 M) enhanced LPS- and FGF-2/-IL-1?induced responses. S100A9 mRNA was not induced by any of these mediators. Induction of S100A8 in the absence of S100A9 was confirmed in primary fibroblast-like cells by real-time reverse-transcriptase polymerase chain-reaction. FGF-2-heparin- and IL-1?induced mRNA expression depended on de-novo protein synthesis and was partially mediated by the mitogenactivated protein kinase pathway of activation. Preliminary promoter deletion analyses indicated that FGF-2-responsive elements in the gene promoter were distinct from those responsive to IL-1? TGF-?(2 ng/ml) significantly suppressed gene induction mediated by FGF-2 ?heparin/LPS/dexamethasone, but not by IL-1? TGF-?may compromise mRNA stability. Protein levels in FGF-2-heparin-IL-1?stimulated fibroblasts correlated well with mRNA levels and expression was mainly cytoplasmic. Immunohistochemistry indicated S100A8 associated with keratinocytes, neutrophils, macrophage-like cells and some hair follicles in wounded rat skin. Rat wounds also contained numerous S100A8- positive fibroblast-like cells 2 and 4 days post-injury; numbers declined by 7 days. Upregulation of S100A8 by FGF-2/IL-1? down-regulation by TGF-? and time-dependent expression of S100A8 in wound fibroblasts suggest a role in fibroblast differentiation at sites of inflammation and repair. Intracellular fibroblast-derived S100A8 may also regulate intracellular redox equilibrium and antioxidant defence. Atherosclerosis is a progressive chronic disease with complex aetiology and pathogenesis. S100A1 and S100B are associated with dendritic cells and lymphocytes in experimental rodent and human atherosclerotic lesions. Monocytes and macrophages in plaques of ApoE???/??? mice express S100A9 but not S100A8. Myeloperoxidase and HOClmediated oxidative mechanisms are fundamental in the pathogenesis of atherosclerosis and S100A8 is exquisitely sensitive to HOCl oxidation which generates sulphinamide bonds, novel non-reducible cysteine-lysine covalent bonds. Chapter 4 of this thesis presents novel evidence that, in contrast to the murine ApoE???/??? model, the three human &quot calgranulins&quot were expressed in human atherosclerotic plaques, but not in normal arteries. High levels of S100A8, S100A9 and S100A12 were evident in macrophages and foam cells. Some neovessels were anti-S100A8-/anti-S100A9-immunoreactive; S100A9 staining was also evident on the extracellular matrix. Patterns of expression of S100A8, S100A9 and S100A12 were overlapping in serial sections, except that only smooth muscle cells were S100A12-positive. S100A8 and S100A9 mRNA were also expressed by macrophages, foam cells and endothelial cells, indicating gene up-regulation rather than passive protein uptake. Western blotting of plaque extracts revealed monomeric S100A8, S100A9 and S100A12 and larger complexes. Some were resistant to reduction, suggesting non-disulfide covalent cross-linking, possibly via sulphinamide bonds. Stable S100A8-S100A9 complexes were also detected after immunoaffinity purification. In an in-vitro system, molar ratios of HOCl of &gt1 generated stable complexes of S100A8 and S100A9 whereas ~800 and ~100-fold excess HOCl oxidises apolipoprotein B-100 and BSA, respectively. S100A8 and S100A9 protected low-density lipoprotein (LDL) against HOCl oxidation in a thiol-independent manner. Because HOCl-oxidised S100s did not contain epitopes recognised by an antibody used to detect HOCl-oxidised proteins in plaque, levels of oxidised proteins in plaque are likely to be significantly greater than described. S100A8 and S100A9 may protect LDL by functioning as HOCl-scavengers. However, chronic oxidative cross-linking of S100A8 and S100A9 with other proteins and extracellular matrix components may contribute to plaque pathogenesis. These studies support key roles for the &quot calgranulins&quot in chronic inflammation, wound healing and atherogenesis possibly by regulating cellular differentiation, activation and modulation of redox-dependent mechanisms.

Thesis (Ph. D.)--University of New South Wales, 2004. / Also available online.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisors: Ulhas P. Naik, Dept. of Biological Sciences and Brian J. Bahnson, Dept. of Chemistry and Biochemistry. Includes bibliographical references.