Preliminary associations between childhood neglect, MIF, and cortisol: potential pathways to long-term disease risk.

The study examined Hypothalamus-Pituitary-Adrenal (HPA) axis and inflammatory signaling in 206 youth with histories of prenatal drug exposure and self-reported histories of maltreatment. Youth with histories of severe neglect showed elevated levels of cortisol, the end product of the HPA axis, in comparison to youth with lower or minimal levels of neglect. Histories of severe neglect also were associated with increased levels of Macrophage Migration Inhibitory Factor (MIF), a cytokine known to be intricately involved in HPA axis regulation. Salivary MIF levels also were positively associated with youth age and prenatal drug exposure. These MIF and cortisol alterations may signal pathophysiological disruptions in the neuro-endocrine and immune systems, which may lead to trajectories of increased disease risk among vulnerable youth. Our findings also provide preliminary support for the validity and reliability of a noninvasive salivary assessment of MIF.

Porphyromonas gingivalis-Induced MIF Regulates Intercellular Adhesion Molecule-1 Expression in EA.hy926 Cells and Monocyte-Endothelial Cell Adhesion Through the Receptors CD74 and CXCR4.

Porphyromonas gingivalis (P. gingivalis) is an important pathogen that contributes to periodontal disease and causes infections that promote the progression of atherosclerosis. Our previous studies showed that macrophage migration inhibitory factor (MIF) facilitates monocyte adhesion to endothelial cells by regulating the expression of intercellular adhesion molecule-1 (ICAM-1) in P. gingivalis-infected endothelial cells. However, the detailed pathological role of MIF has yet to be elucidated in this context. To explore the functional receptor(s) of MIF that underlie its participation in the pathogenesis of atherosclerosis, we investigated the expression of the chemokine receptors CD74 and CXCR4 in endothelial cells, both of which were shown to be involved in the adhesion of monocytes to endothelial cells pretreated with P. gingivalis. Furthermore, the formation of a MIF, CD74, and CXCR4 ligand-receptor complex was revealed by our immunofluorescence staining and coimmunoprecipitation results. By interacting with the CD74/CXCR4 receptor complex, MIF may act as a crucial regulator of monocyte-endothelial cell adhesion and promote the atherosclerotic plaque formation induced by P. gingivalis.

Macrophage migration inhibitory factor (MIF) gene is associated with adolescents' cortisol reactivity and anxiety.

Emerging evidence points to interactions between inflammatory markers and stress reactivity in predicting mental health risk, but underlying mechanisms are not well understood. Macrophage Migration Inhibitory Factor (MIF) is a pleiotropic cytokine involved in inflammatory signaling and Hypothalamus Pituitary Adrenal (HPA) axis stress-response, and has recently been identified as a candidate biomarker for depression and anxiety risk. We examined polymorphic variations of the MIF gene in association with baseline MIF levels, HPA axis reactivity, and self-reported anxiety responses to a social stressor in 74 adolescents, ages 10-14 years. Genotyping was performed for two polymorphisms, the -794 CATT5-8 tetranucleotide repeat and the -173*G/C single nucleotide polymorphism (SNP). Youth carrying the MIF-173*C and CATT7 alleles displayed attenuated cortisol reactivity when compared with non-carriers. Children with the CATT7-173*C haplotype displayed lower cortisol reactivity to the stressor compared to those without this haplotype. Additionally, the CATT5-173*C and CATT6-173*C haplotypes were associated with lower self-reported anxiety ratings across the stressor. Results extend prior work pointing to the influence of MIF signaling on neuroendocrine response to stress and suggest a potential pathophysiological pathway underlying risk for stress-related physical and mental health disorders. To our knowledge, these are the first data showing associations between the MIF gene, HPA axis reactivity, and anxiety symptoms during adolescence.

Membrane-bound prostaglandin E synthase-1-mediated prostaglandin E2 production by osteoblast plays a critical role in lipopolysaccharide-induced bone loss associated with inflammation.

PGE(2) acts as a potent stimulator of bone resorption in several disorders including osteoarthritis and periodontitis. Three PGE synthases (PGES) were isolated for PGE(2) production, but which PGES has the major role in inflammatory bone resorption is still unclear. In this study, we examined the role of PGE(2) in LPS-induced bone resorption using membrane-bound PGES (mPGES)-1-deficient mice (mPges1(-/-)). In osteoblasts from wild-type mice, PGE(2) production was greatly stimulated by LPS following the expression of cyclooxygenase 2 and mPGES-1 mRNA, whereas no PGE(2) production was found in osteoblasts from mPges1(-/-). LPS administration reduced the bone volume in wild-type femur that was associated with an increased number of osteoclasts. In mPges1(-/-), however, LPS-induced bone loss was reduced. We next examined whether mPGES-1 deficiency could alter the alveolar bone loss in LPS-induced experimental periodontitis. LPS was injected into the lower gingiva and bone mineral density of alveolar bone was measured. LPS induced the loss of alveolar bone in wild-type, but not in mPges1(-/-) mice, suggesting an mPGES-1 deficiency resistant to LPS-induced periodontal bone resorption. To understand the pathway of LPS-induced PGE(2) production in osteoblast, we used C3H/HeJ mice with mutated tlr4. Osteoblasts from C3H/HeJ mice did not respond to LPS, and PGE(2) production was not altered at all. LPS-induced bone loss in the femur was also impaired in C3H/HeJ mice. Thus, LPS binds to TLR4 on osteoblasts that directly induce mPGES-1 expression for PGE(2) synthesis, leading to subsequent bone resorption. Therefore, mPGES-1 may provide a new target for the treatment of inflammatory bone disease.