WNT/β-catenin pathway and circadian rhythms in obsessive-compulsive disorder

The neuropsychiatric disease named obsessive-compulsive disorder is composed by obsessions and/or compulsions.Obsessive-compulsive disorder etiologies are undefined.However,numerous mechanisms in several localizations are implicated.Some studies showed that both glutamate,inflammatory factors and oxidative stress could have main functions in obsessive-compulsive disorder.Glycogen synthase kinase-3β,the major negative controller of the WNT/β-catenin pathway is upregulated in obsessive-compulsive disorder.In obsessive-compulsive disorder,some studies presented the actions of the different circadian clock genes.WNT/β-catenin pathway and circadian clock genes appear to be intricate.Thus,this review focuses on the interaction between circadian clock genes and the WNT/β-catenin pathway in obsessive-compulsive disorder.

Opposite Interplay Between the Canonical WNT/β-Catenin Pathway and PPAR Gamma： A Potential Therapeutic Target in Gliomas

In gliomas, the canonical Wingless/Int（WNT）/b-catenin pathway is increased while peroxisome proliferator-activated receptor gamma（PPAR-c） is downregulated.The two systems act in an opposite manner. This review focuses on the interplay between WNT/b-catenin signaling and PPAR-c and their metabolic implications as potential therapeutic target in gliomas. Activation of the WNT/bcatenin pathway stimulates the transcription of genes involved in proliferation, invasion, nucleotide synthesis,tumor growth, and angiogenesis. Activation of PPAR-c agonists inhibits various signaling pathways such as the JAK/STAT, WNT/b-catenin, and PI3 K/Akt pathways,which reduces tumor growth, cell proliferation, cell invasiveness, and angiogenesis. Nonsteroidal anti-inflammatory drugs, curcumin, antipsychotic drugs, adiponectin,and sulforaphane downregulate the WNT/b-catenin pathway through the upregulation of PPAR-c and thus appear to provide an interesting therapeutic approach for gliomas.Temozolomide（TMZ） is an antiangiogenic agent. The downstream action of this opposite interplay may explain the TMZ-resistance often reported in gliomas.

I L- 15 trans-presentation regulates homeostasis of CD4^＋ T lymphocytes

Interleukin-15 （IL-15） is essential for the survival of memory CD8^＋ and CD4^＋ T cell subsets, and natural killer and natural killer T cells. Here, we describe a hitherto unreported role of IL-15 in regulating homoeostasis of naive CD4^＋ T cells. Adoptive transfer of splenocytes from non-obese diabetic （NOD） mice results in increased homeostatic expansion of T cells in lymphopenic NOD.scid.II15^-/- mice when compared to NOD.scid recipients. The increased accumulation of CD4^＋ T cells is also observed in NOD.II15^-/- mice, indicating that IL-15-dependent regulation also occurs in the absence of lymphopenia. NOD.scid mice lacking the I L- 15Ra chain, but not those lacking the common gamma chain, also show increased accumulation of CD4^＋ T cells. These findings indicate that the IL-15-mediated regulation occurs directly on CD4^＋ T cells and requires trans-presentation of IL-15. CD4^＋ T cells expanding in the absence of IL-15 signaling do not acquire the characteristics of classical regulatory T cells. Rather, CD4^＋ T cells expanding in the absence of IL-15 show impaired antigen-induced activation and IFN-7 production. Based on these findings, we propose that the IL-15-dependent regulation of the naive CD4^＋ T-cell compartment may represent an additional layer of control to thwart potentially autoreactive cells that escape central tolerance, while permitting the expansion of memory T cells.