Summary Differences in susceptibility to immune-mediated diseases are determined by variability in immune responses. In three studies within the Human Functional Genomics Project we assessed the effect of environmental and non-genetic host factors, of the genetic make-up of the host, and of the intestinal microbiome, on the cytokine responses in humans. We analyzed the association of these factors with circulating mediators and with six cytokines after stimulation with 19 bacterial, fungal, viral and non-microbial metabolic stimuli in 534 healthy subjects. In this first study we show a strong impact of non-genetic host factors (e.g. age and gender) on cytokine production and circulating mediators. Additionally, annual seasonality is found to be an important environmental factor influencing cytokine production. Alpha-1-antitrypsin concentrations partially mediate the seasonality of cytokine responses, whereas the effect of vitamin D levels is limited. The complete dataset has been made publicly available as a comprehensive resource for future studies.

Receptor-mediated cholesterol uptake has been suggested to play a role in maintaining the adrenal intracellular free cholesterol pool and the ability to produce hormones. Therefore, in the current study, we evaluated the importance of scavenger receptor class B type I (SR-BI)-mediated cholesteryl ester uptake from HDL for adrenal glucocorticoid hormone synthesis in vivo. No difference was observed in the plasma level of corticosterone between SR-BI-deficient and wild-type mice under ad libitum feeding conditions. Overnight fasting (?16 h) stimulated the plasma level of corticosterone by 2-fold in wild-type mice. In contrast, no effect of fasting on plasma corticosterone levels was observed in SR-BI-deficient mice, leading to a 44% lower plasma corticosterone level compared with their wild-type littermate controls. In parallel, an almost complete depletion of lipid stores in the adrenal cortex of fasted SR-BIdeficient mice was observed. Plasma adrenocorticotropic hormone levels were increased by 5-fold in fasted SR-BIdeficient mice. SR-BI deficiency induced marked changes in the hepatic expression of the glucocorticoid-responsive genes cholesterol 7a-hydroxylase, HMG-CoA synthase, apolipoprotein A-IV, corticosteroid binding globulin, interleukin-6, and tumor necrosis factor-a, which coincided with a 42% decreased plasma glucose level under fasting conditions. In conclusion, we show that the absence of adrenal HDL cholesteryl ester uptake in SR-BI-deficient mice impairs the adrenal glucocorticoid-mediated stress response to fasting as a result of adrenal glucocorticoid insufficiency and attenuated liver glucocorticoid receptor signaling, leading to hypoglycemia under fasting conditions.-Hoekstra, M., I. Meurs, M. Koenders, R. Out, R. B. Hildebrand, J. K. Kruijt, M. Van Eck, and T. J. C. Van Berkel. Absence of HDL cholesteryl ester uptake in mice via SR-BI impairs an adequate adrenal glucocorticoid-mediated stress response to fasting. J. Lipid Res. 2008. 49: 738-745.

Parenchymal destruction, airspace enlargement, and loss of elasticity are hallmarks of pulmonary emphysema. Although the basic mechanism is unknown, there is a consensus that malfunctioning of the extracellular matrix is a major contributor to the pathogenesis of emphysema. In this study, we analyzed the expression of the elastic fiber protein fibrillin-1 in a large number (n ¼ 69) of human lung specimens with early-onset emphysema. Specimens were morphologically characterized by the Destructive Index, the Mean Linear Intercept, and the Panel Grading. We observed a strong correlation (Po0.001) of aberrant fibrillin-1 staining with the degree of destruction of lung parenchyma (r ¼ 0.71), airspace enlargement (r ¼ 0.47), and emphysema-related morphological abnormalities (r ¼ 0.69). There were no obvious correlations with age and smoking behavior. Staining for three other extracellular matrix components (type I collagen, type IV collagen, and laminin) was not affected. The aberrant fibrillin-1 staining observed in this study is similar to that observed in Marfan syndrome, a syndrome caused by mutations in the gene encoding fibrillin-1. Strikingly, emphysema is noticed in a number of Marfan patients. This, together with the notion that disruption of the fibrillin-1 gene in mice results in emphysematous lesions, makes fibrillin-1 a strong candidate to be involved in the etiology and pathogenesis of emphysema.

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