Enhanced susceptibility to low-dose collagen-induced arthritis in CR1/2-deficient female mice--possible role of estrogen on CR1 expression.

The influence of complement receptor 1 and 2 (CR1/2) was investigated on the susceptibility to low-dose collagen-induced arthritis (CIA) in wild-type (WT) and CR1/2-deficient DBA/1 mice. Significantly enhanced CIA was observed in female CR1/2-deficient mice compared with WT female mice, while male mutant and WT mice showed similar arthritis development. The enhanced CIA was accompanied with higher complement levels and a prolonged IgM anti-collagen type II response. When investigating whether estrogen contributed to the different arthritis susceptibility, we found that ovariectomy rendered WT females more sensitive to low-dose CIA and to the same extent as CR1/2-deficient females, while CR1/2-deficient mice were unaffected by ovariectomy. Notably, the ovariectomized WT mice displayed reduced CR1(+) B220(+) B-cell numbers and CR1 expression compared with sham-operated WT mice, suggesting a stimulatory effect of estrogen on CR1. In accordance, a significant correlation was observed between reduced CR1 expression in B cells and increased age in healthy female blood donors but not in male donors. Our findings demonstrate an important role of CR1/2 in suppressing CIA in female mice under low-antigen conditions. The data suggest that estrogen promote CR1 expression in B cells. These findings provide insight to the increased frequency of rheumatoid arthritis in postmenopausal women.

Emulsifying and Anti-Oxidative Properties of Proteins Extracted from Industrially Cold-Pressed Rapeseed Press-Cake.

One of the functional proteins in rapeseed-the amphiphilic protein oleosin-could be used to stabilize emulsions. The objectives of this study were to extract oleosins from cold-pressed rapeseed press-cake, optimize the extraction process, and investigate their emulsifying and anti-oxidative capacity. The proteins were recovered from industrially cold-pressed rapeseed press-cake at different alkali pHs. Emulsifying properties and oxidation rates were assessed. Oleosin extracted at pH 9 stabilized smaller emulsion droplets than oleosin extracted at pH 12, although the protein yield was higher at pH 12. Emulsions were formulated from flaxseed oil and corn oil and were stabilized by oleosin, bovine serum albumin, de-oiled lecithin and Tween 20,h and the emulsions were stored in accelerated conditions (30 °C) for 12 days. Oleosin stabilized emulsions to the same extent as commercial food-grade emulsifiers. Flaxseed oil emulsions stabilized by oleosin had a significantly lower concentration of malondialdehyde (MDA) which indicates a lower oxidation rate compared to BSA, de-oiled lecithin and Tween 20. For corn oil emulsions, oleosin and BSA had a similar capacity to delay oxidation and were significantly more efficient compared to de-oiled lecithin and Tween 20. Rapeseed oleosin recovered from cold-pressed rapeseed press-cake could be a suitable natural emulsifier with anti-oxidation properties.

The Effects of Oil Extraction Methods on Recovery Yield and Emulsifying Properties of Proteins from Rapeseed Meal and Press Cake.

The agricultural sector is thought to be responsible for around 30% of the anthropogenic climate change and it is well established that high meat consumption has a tremendous impact on the environment. Rapeseed is mainly used for production of vegetable oil, but press cake has high protein content with the potential for incorporation into new plant protein-based foods. Protein was recovered from press cakes generated from different oil pressing processes. Industrially cold-pressed, hot-pressed, and solvent-extracted rapeseed press cake and the effect of heat treatment in the recovery process was assessed. Protein recovery yield, protein concentration and emulsifying properties were analyzed. Cold-pressed rapeseed press cake (RPC) recovered in the absence of heat, yielded the highest protein recovery (45%) followed by hot-pressed rapeseed meal (RM) (26%) and solvent-extracted RM (5%). Exposure to heat during recovery significantly reduced the yield for cold-pressed RPC but no difference was found for hot-pressed RM. The protein recovery yield was improved for solvent-extracted RM when heat was applied in the recovery process. The ability to stabilize emulsions was highest for protein recovered from cold-pressed RPC, followed by hot-pressed RM and solvent-extracted RM, and was in the same range as commercial emulsifying agents. Heat treatment during recovery significantly reduced the emulsifying properties for all pressing methods examined. This study suggests that cold-pressed rapeseed press cake without heat in the recovery process could be a successful strategy for an efficient recovery of rapeseed protein with good emulsifying properties.

Amelioration of collagen-induced arthritis by human recombinant soluble FcgammaRIIb.

Immune complex (IC) binding to Fc gamma receptors (FcgammaRs) is central for inflammatory reactions seen in autoimmune diseases. Consequently, a therapeutic agent with a possibility to interfere with binding of pathogenic IC to FcgammaRs would be valuable in autoimmune disorders such as rheumatoid arthritis (RA). Here we have explored the therapeutic effect of a recombinant soluble human FcgammaRIIb (sFcgammaRIIb) protein in collagen-induced arthritis (CIA). In vitro studies of the sFcgammaRIIb demonstrated binding to mouse IgG, suggesting that sFcgammaRIIb can absorb pathogenic IgG anti-collagen type II (CII) IC in vivo. Hence, administration of sFcgammaRIIb significantly reduced CIA severity compared to control treated mice. The sFcgammaRIIb treated mice had significantly less IgG anti-CII antibodies in serum and lower mRNA levels of inflammatory cytokines compared to control mice. In conclusion, sFcgammaRIIb treatment ameliorates CIA by reducing IC-stimulated inflammation and joint swelling. This suggests that recombinant sFcgammaRIIb may be useful as therapeutic agent in RA.

Age-related enlargement of lymphoid tissue and altered leukocyte composition in serglycin-deficient mice.

Serglycin (SG) is a proteoglycan that is located predominantly in the secretory granules of hematopoietic cells. Previous studies have established a crucial role for SG in promoting the storage of various secretory granule compounds that are of importance in the immune defense system. Here, we show that mice lacking SG spontaneously develop enlargement of multiple lymphoid organs, including the spleen, Peyer's patches (PP), and bronchus-associated lymphoid tissue. In the spleen, the lack of SG resulted in a significant decrease in the proportion of CD4(+) cells as well as an increase of the CD45RC(+) leukocyte population, indicating an expansion of naïve lymphocytes. In the PP, the lack of SG resulted in a general increase in cellularity, without significant alterations in the proportion of individual leukocyte populations. The enlargement of lymphoid tissues was not accompanied by increased serum levels of inflammatory cytokines. The number of mast cells in the peritoneum was not affected by the lack of SG, as judged by surface staining for CD117 (c-kit). However, the intensity of c-kit staining was reduced significantly in SG null animals. Moreover, the number of peritoneal macrophages, defined by morphological criteria and by CD11b staining, was decreased markedly in older, SG-deficient animals. Finally, experiments in which airway inflammation was induced by bacterial LPS revealed a more pronounced inflammatory response in old, SG-deficient as compared with wild-type mice. Taken together, our data show that SG deficiency causes multiple, age-related effects on the lymphoid system.