Search

Regulatory T (Treg) cells play an integral role in maintaining immune homeostasis and preventing autoimmune diseases. Forkhead box P3 expression marks the commitment of progenitor cells to the Treg lineage. Although the essential function of the nuclear factor (NF)-κB family transcription factor c-Rel in the regulation of natural Treg cells has been firmly established, little is known about whether c-Rel is involved in the in vivo generation of peripheral Treg cells (pTregs), which develop from mature CD4+ conventional T cells outside of the thymus. We sought to answer this question through the induction of pTregs in the eye and gut mucosa using ovalbumin-specific T cell receptor transgenic mice that do or do not express c-Rel. Our results showed that Tregs can be induced in the eye in a c-Rel-dependent manner when immune-mediated inflammation occurs. However, c-Rel is dispensable for the induction of pTregs in the gut mucosa after oral antigen administration. Thus, c-Rel may play distinct roles in regulating the development of pTregs in different organs. Abbreviations ACAID: Anterior Chamber-Associated Immune Deviation; ATF: activating transcription factor; CREB: cAMP responsive element-binding protein; DMEM: Dulbecco minimum essential medium; HBSS: Hanks Balanced Salt Solution; NFAT: Nuclear Factor of Activated T cells; PBS: Phosphate-buffered saline; PE: Phycoerythrin; WT: wild type.

Phenotypic switching of vascular smooth muscle cells (VSMCs) is known to play a key role in the development of atherosclerosis. However, the mechanisms that mediate VSMC phenotypic switching are unclear. We report here that TIPE2, the tumor necrosis factor (TNF) α-induced protein 8-like 2 (TNFAIP8L2), plays an atheroprotective role by regulating phenotypic switching of VSMCs in response to oxidized low-density lipoprotein (ox-LDL) stimuli. TIPE2-deficient VSMCs treated with ox-LDL expressed lower levels of contractile proteins such as SMαA, SM-MHC and calponin, whereas the proliferation, migration and the synthetic capacity for growth factors and cytokines were increased remarkably. Furthermore, TIPE2 inhibited VSMCs proliferation by preventing G 1/S phase transition. Interestingly, these effects of TIPE2 on VSMCs were dependent on P38 and ERK1/2 kinase signals. As a result, neointima formation was accelerated in the carotid arteries of TIPE2-deficient mice. These results indicate that TIPE2 is a potential inhibitor of atherosclerosis.

Autoimmune encephalomyelitis can be initiated spontaneously and developed progressively in TCR transgenic mice specific for myelin basic protein when exposed to non-sterile environment, thus more closely mimicking human multiple sclerosis. By intravenous administration of myelin basic protein, we succeeded in reversing the clinical and pathological signs of progressive spontaneous disease in these mice. Flow cytometry showed that the majority of transgenic T cells in lymph nodes and spleen as well as spinal cords of treated mice were deleted. Dramatically increased numbers of apoptotic cells were found in peripheral immune organs of treated animals. Proliferative responses of single transgenic T cell to autoantigen were significantly decreased in treated mice, indicating that the remaining T cells were anergic. Moreover, production of both Th1 and Th2 cytokines was suppressed. This study is the first demonstration of reversal of progressive, spontaneous autoimmune disease of the central nervous system, and provides direct evidence that apoptosis-induced clonal deletion, along with anergy of remaining cells, but not Th2 switch, play a major part in the reversal of this disease by intravenous administration of autoantigen.

A review of: Suicide Gene Therapy: Methods and Reviews Edited by Caroline J. Springer Humana Press: 2004.