Activation of immune responses against the basement membrane component collagen type IV does not affect the development of atherosclerosis in ApoE-deficient mice

Abstract

Oxidation of low-density lipoprotein (LDL) in the arterial extracellular matrix results in malondialdehyde (MDA)-modifications of surrounding matrix proteins. We have recently demonstrated an association between high levels of autoantibodies against MDA-modified collagen type IV and risk for development of myocardial infarction. Collagen type IV is an important component of the endothelial basement membrane and influences smooth muscle cell function. We hypothesized that immune responses against collagen type IV could contribute to vascular injury affecting the development of atherosclerosis. To investigate this possibility, we induced an antibody-response against collagen type IV in apolipoprotein E (Apo E)-deficient mice. Female ApoE −/− mice on C57BL/6 background were immunized with α1α2 type IV collagen chain peptides linked to the immune-enhancer PADRE, PADRE alone or PBS at 12 weeks of age with three subsequent booster injections before the mice were killed at 23 weeks of age. Immunization of PADRE alone induced autoantibodies against PADRE, increased IL-4 secretion from splenocytes and reduced SMC content in the subvalvular plaques. Immunization with peptides of α1α2 type IV collagen chains induced a strong IgG1antibody response against collagen type IV peptides without affecting the distribution of T cell populations, plasma cytokine or lipid levels. There were no differences in atherosclerotic plaque development between collagen α1α2(IV)-PADRE immunized mice and control mice. Our findings demonstrate that the presence of antibodies against the basement membrane component collagen type IV does not affect atherosclerosis development in ApoE −/− mice. This suggests that the association between autoantibodies against collagen type IV and risk for myocardial infarction found in humans does not reflect a pathogenic role of these autoantibodies.

Antibodies against apoB100 peptide 210 inhibit atherosclerosis in apoE-/- mice

“…Analyses of induced antibodies in mice were performed mainly as previously described by Vallejo et al 32 . p210, p210-PADRE, or PADRE peptides were used for coating (20 μg/mL of each in PBS) microtiter plates (Nunc MaxiSorp, Nunc) over night at 4 °C.…”

“…Single-cell suspensions of splenocytes were prepared by pressing spleens through a 70-μm cell strainer (BD Falcon) as previously described 32 . Erythrocytes were removed using red blood cell lysing buffer (Sigma-Aldrich).…”

Screening of Self-Assembling of Collagen IV Fragments into Stable Structures Potentially Useful in Regenerative Medicine

“…Additionally, in the case of collagen IV, its participation in the immunoreactivity of basement membrane in the inflammatory process was demonstrated [66,67]. In addition, it has been found that an elevated level of collagen IV, as well as the presence of collagen IV fragments, may be either a biomarker of the disease state [68][69][70] or show variable biological activity, such as cell growth, differentiation and migration, regulators of angiogenesis, inhibitors of metalloproteinases, dipeptidylpeptidase-IV [71][72][73][74].…”

Recognition of Oxidized Lipids by Macrophages and Its Role in Atherosclerosis Development

“…The subendothelial retention and oxidation of LDL also results in MDA-modifications of surrounding extracellular matrix proteins, including fibronectin, collagen type I-IV and ten ascin-C [ 30 , 31 ], giving rise to new potential antigens. MDA-collagen type IV-specific IgG antibodies were shown to be associated with more severe carotid disease and increased risk of myocardial infarction [ 32 ].…”

“…Conversely, certain lipids and their derivatives may serve as M2 macrophage polarization signals. Among such agents are 9-oxononanoyl-cholesterol, a major cholesteryl ester oxidation product [ 31 ], and resolvin D1 [ 11 ].…”