The genetic programs directing CD4 or CD8 T cell differentiation in the thymus remain poorly understood. While analyzing gene expression during intrathymic T cell selection, we found that Zfp67, encoding the zinc finger transcription factor cKrox, was upregulated during the differentiation of CD4(+) but not CD8(+) T cells. Expression of a cKrox transgene impaired CD8 T cell development and caused major histocompatibility complex class I-restricted thymocytes to differentiate into CD4(+) T cells with helper properties rather than into cytotoxic CD8(+) T cells, as normally found. CD4 lineage differentiation mediated by cKrox required its N-terminal BTB (bric-a-brac, tramtrack, broad complex) domain. These findings identify cKrox as a chief CD4 differentiation factor during positive selection.
AbtractEpithelial–mesenchymal transition (EMT) is an important contributor to the invasion and metastasis of epithelial-derived cancers. While considerable effort has focused in the regulators involved in the transition process, we have focused on consequences of EMT to prosurvival signaling. Changes in distinct metastable and ‘epigentically-fixed’ EMT states were measured by correlation of protein, phosphoprotein, phosphopeptide and RNA transcript abundance. The assembly of 1167 modulated components into functional systems or machines simplified biological understanding and increased prediction confidence highlighting four functional groups: cell adhesion and migration, metabolism, transcription nodes and proliferation/survival networks. A coordinate metabolic reduction in a cluster of 17 free-radical stress pathway components was observed and correlated with reduced glycolytic and increased oxidative phosphorylation enzyme capacity, consistent with reduced cell cycling and reduced need for macromolecular biosynthesis in the mesenchymal state. An attenuation of EGFR autophosphorylation and a switch from autocrine to paracrine-competent EGFR signaling was implicated in the enablement of tumor cell chemotaxis. A similar attenuation of IGF1R, MET and RON signaling with EMT was observed. In contrast, EMT increased prosurvival autocrine IL11/IL6-JAK2-STAT signaling, autocrine fibronectin-integrin α5β1 activation, autocrine Axl/Tyro3/PDGFR/FGFR RTK signaling and autocrine TGFβR signaling. A relatively uniform loss of polarity and cell–cell junction linkages to actin cytoskeleton and intermediate filaments was measured at a systems level. A more heterogeneous gain of ECM remodeling and associated with invasion and migration was observed. Correlation to stem cell, EMT, invasion and metastasis datasets revealed the greatest similarity with normal and cancerous breast stem cell populations, CD49fhi/EpCAM-/lo and CD44hi/CD24lo, respectively.Electronic supplementary materialThe online version of this article (doi:10.1007/s10585-010-9367-3) contains supplementary material, which is available to authorized users.
In multiple sclerosis, in which brain tissue becomes permeable to blood proteins, extravascular fibrin deposition correlates with sites of inflammatory demyelination and axonal damage. To examine the role of fibrin in neuroinflammatory demyelination, we depleted fibrin in two tumor necrosis factor transgenic mouse models of multiple sclerosis, transgenic lines TgK21 and Tg6074. In a genetic analysis, we crossed TgK21 mice into a fibrin-deficient background. TgK21fib ؊/؊ mice had decreased inflammation and expression of major histocompatibility complex class I antigens, reduced demyelination, and a lengthened lifespan compared with TgK21 mice. In a pharmacologic analysis, fibrin depletion, by using the snake venom ancrod, in Tg6074 mice also delayed the onset of inflammatory demyelination. Overall, these results indicate that fibrin regulates the inflammatory response in neuroinflammatory diseases. Design of therapeutic strategies based on fibrin depletion could potentially benefit the clinical course of demyelinating diseases such as multiple sclerosis.autoimmunity ͉ anticoagulants ͉ ancrod ͉ extracellular matrix F ibrin, as the final product of the coagulation cascade, plays a major role in blood clotting. However, the role of fibrin is not restricted to the blood, since components of the coagulation cascade reside within tissues and can stimulate extravascular fibrin formation (1). Studies of fibrin deposition in human diseases (2-5), in combination with experiments from genetargeted mice deficient in fibrin (6), have shown that a wide range of pathological conditions, such as glomerulonephritis, lung ischemia, and rheumatoid arthritis, are exacerbated by fibrin deposition.Compromised vasculature in the nervous tissue is a pathogenic manifestation apparent in traumatic injuries, such as spinal cord, optic nerve, and sciatic nerve injury, as well as in central nervous system (CNS) diseases with autoimmune characteristics, such as multiple sclerosis (MS) (7). Blood-brain barrier (BBB) disruption precedes clinical symptoms in MS patients (8), and fibrin is deposited in the lesions (9, 10), apparently before cerebral tissue injury and demyelination (11). Fibrin deposition also coincides with areas of demyelination (12), as well as with areas of axonal damage (13). In addition, in experimental autoimmune encephalomyelitis (EAE), an autoimmune animal model of MS, there is increased coagulation activation before symptom development (14). Pharmacologic depletion of fibrin in EAE ameliorates clinical symptoms, suggesting that fibrin plays a role in CNS inflammatory demyelination (15, 16). Furthermore, inhibition of fibrin formation by attenuation of thrombin activity is protective in the injured optic nerve (17).Although extravascular fibrin(ogen) is present at sites of inflammatory demyelination in MS, and experiments in rodents have established a deleterious role for fibrin in nervous system pathogenesis (18), the cellular mechanisms of fibrin action in the CNS have not been investigated. In this study we examined th...
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