Factors accounting for the association between anxiety and depression, and eczema: the Hordaland health study (HUSK)

<p>Abstract</p> <p>Background</p> <p>The association between anxiety and depression, and eczema is well known in the literature, but factors underlying this association remain unclear. Low levels of omega-3 fatty acids and female gender have been found to be associated with both depression and eczema. Somatization and health anxiety are known to be associated with anxiety and depression, further, somatization symptoms and health anxiety have also been found in several dermatological conditions. Accordingly, omega-3 fatty acid supplement, female gender, somatization and health anxiety are possible contributing factors in the association between anxiety and depression, and eczema. The aim of the study is to examine the relevance of proposed contributing factors for the association between anxiety and depression, and eczema, including, omega-3 fatty acid supplement, female gender, health anxiety and somatization.</p> <p>Methods</p> <p>Anxiety and depression was measured in the general population (n = 15715) employing the Hospital Anxiety and Depression Scale (HADS). Information on eczema, female gender, omega-3 fatty acid supplement, health anxiety and somatization was obtained by self-report.</p> <p>Results</p> <p>Somatization and health anxiety accounted for more than half of the association between anxiety/depression, and eczema, while the other factors examined were of minor relevance for the association of interest.</p> <p>Conclusions</p> <p>We found no support for female gender and omega-3 fatty acid supplement as contributing factors in the association between anxiety/depression, and eczema. Somatization and health anxiety accounted for about half of the association between anxiety/depression, and eczema, somatization contributed most. The association between anxiety/depression, and eczema was insignificant after adjustment for somatization and health anxiety. Biological mechanisms underlying the mediating effect of somatization are yet to be revealed.</p

Phosphorylation/dephosphorylation of high-affinity IgE receptors: a mechanism for coupling/uncoupling a large signaling complex.

Engagement of high-affinity IgE receptors leads to activation of tyrosine and serine/threonine kinases and the immediate phosphorylation of receptor beta (serine and tyrosine) and gamma (threonine and tyrosine) chains. Receptor disengagement leads to dephosphorylation of beta and gamma chains via the action of undefined phosphatases. Here we have identified five distinct polypeptides associated with the high-affinity IgE-receptor tetrameric complex, which apparently become phosphorylated and dephosphorylated in sequence with the beta and gamma chains. Like beta chain, polypeptides pp180, pp48, pp42, and pp28 are phosphorylated on serine and tyrosine, whereas pp125 is only phosphorylated on serine. The phosphorylation of each of these receptor-associated polypeptides is antigen-dose dependent and is restricted to activated receptor complexes. Furthermore the physical association between pp125 and the receptor is quantitatively affected by receptor phosphorylation and dephosphorylation, indicating a coupling-uncoupling mechanism. Finally, in vitro kinase experiments show that activated receptor complexes are also physically associated with tyrosine and serine/threonine kinases as part of a larger complex containing the phosphorylated polypeptides

IgE receptor (FcepsilonRI) and signal transduction.

This review suggests a model in which both beta- and gamma-chains synergize in the initiation of Fc epsilon RI signal transduction function. Receptor aggregation by antigens induces activation of lyn, which is already bound to the Fc epsilon RI beta-chain under resting conditions. Whilst activated, lyn would phosphorylate the tyrosine residues in the Fc epsilon RI gamma-chain. This phosphorylation would be responsible for the recruitment of syk (probably via its SH2 domains) as well as other signalling molecules. Syk kinase would then be activated by the engagement of its SH2 domains and/or its phosphorylation. Syk could then interact with and activate (through phosphorylation) downstream effector molecules

Syk dependent phosphorylation of shc. A potential link between FcepsilonRI and Ras/mitogen-activated protein kinase signaling pathway through SOS and Grb2

Antigen receptors on T- and B-cells activate Ras through a signaling pathway that results in the tyrosine phosphorylation of Shc and the formation of a complex of Shc with the Grb2 adaptor protein. The high affinity receptor for immunoglobulin E (FcepsilonRI) in cultured mast (RBL-2H3) cells has been reported to function differently. Here we show to the contrary that engagement of FcepsilonRI with antigen leads to increased tyrosine phosphorylation of Shc and the association of Shc with Grb2 and other proteins (p120 and p140). Like the FcepsilonRI-mediated activation of the mitogen-activated protein kinase cascade, these responses are dependent on the tyrosine kinase Syk; they are enhanced by overexpression of Syk and are blocked by expression of dominant-negative Syk. Sos is constitutively associated with Grb2 in these cells but dissociates from Shc on stimulation with antigen. These reactions are rapid, reversible, and associated with the activation of Ras. Therefore, the Syk-dependent tyrosine phosphorylation of Shc and its association with Grb2 may provide a pathway through Sos for activation of Ras by FcepsilonRI