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Polarization of cell phenotypes, a common strategy to achieve cell type diversity in metazoa, results from binary cell-fate decisions in the branching pedigree of development. Such “either-or” fate decisions are controlled by two opposing cell fate-determining transcription factors. Each of the two distinct “master regulators” promotes differentiation of its respective sister lineage. But they also suppress one other, leading to their mutually exclusive expression in the two ensuing lineages. Thus, promiscuous coexistence of the antagonist regulators in the same cell, the hallmark of the common “undecided” progenitor of two sister lineages, is considered unstable. This antagonism ensures robust polarization into two discretely distinct cell types. But now the immune system's T-helper (Th) cells and their two canonical subtypes, Th1 and Th2 cells, tell a different story, as revealed in three papers recently published in PLOS Biology. The intermediate state that co-expresses the two opposing master regulators of the Th1 and Th2 subtypes, T-bet and Gata3, is highly stable and is not necessarily an undecided precursor. Instead, the Th1/Th2 hybrid cell is a robust new type with properties of both Th1 and Th2 cells. These hybrid cells are functionally active and possess the benefit of moderation: self-limitation of effector T cell function to prevent excessive inflammation, a permanent risk in host defense that can cause tissue damage or autoimmunity. Gene regulatory network analysis suggests that stabilization of the intermediate center in a polarizing system can be achieved by minor tweaking of the architecture of the mutual suppression gene circuit, and thus is a design option readily available to evolution. [ABSTRACT FROM AUTHOR]

Abstract: The vasoactive intestinal peptide (VIP)-VPAC1 and VPAC2 G protein-coupled receptor (GPCR) systems are autocrine and paracrine regulators of diverse T cell functions. It has been recognized that VIP evokes two types of T cell responses. The first are rapid in onset and brief in duration, such as altered traffic in blood, lymphoid corridors, and tissues. The second are slow in onset and sustained in duration, such as enhanced helper T cell (Th) differentiation in the thymus and increased survival in lymphoid tissues with biases favoring the Th2-type effector and memory subsets. Investigations of some other sets of GPCRs for peptide and lipid mediators have demonstrated expression both in nuclear membranes and plasma membranes with respective linkages to responses that are slow in onset and sustained, and those that are rapid in onset and brief in duration. The hypothesis presented in this paper suggests that plasma membrane VPAC receptors transduce short-term effects of exogenous VIP on T cell effector functions, whereas nuclear VPAC receptors mediate endogenous VIP alterations in differentiation, proliferation, and survival. The types of substantial additional proof needed to support this hypothesis are described, as are its advantages for more selective VIP-directed therapies. [Copyright &y& Elsevier]

Objective It has been suggested that the development of uterine leiomyomas is positively influenced by an immune system in a chronically inflammatory state and that a lower level of regulating T cell (Treg cells) would play a central role. Since it has been suggested that the W620 variant of protein tyrosine phosphatase non-receptor type 22 (PTPN22) decreases the number of Treg cells, we investigated a possible relationship between PTPN22 polymorphism and uterine leiomyomas. Study design We studied 203 white women from Rome who were hospitalized for symptomatic leiomyomas requiring surgical intervention. These women were considered in a previous paper regarding the relationship between ACP1 and dimension of leiomyomas. As controls we studied 355 healthy women from the same population with comparable age and without clinical evidence of leiomyomas. All women gave written informed consent to participate to the study. Chi square test of independence and T -test for difference between means were performed by SPSS package. Results Considering the whole sample, a borderline association between PTPN22 and leiomyomas was observed: the *C/*T genotype is more frequent in cases than in controls. This association is marked and statistically significant in younger women only. The main diameter of tumor is significantly greater in *C/*T than in *C/*C women. This effect is present in younger women only. The *C/*T genotype also shows a higher tendency to intramural localization, but no effect of age is observed upon this association. Conclusions The data suggest a positive effect of *C/*T genotype on susceptibility to leiomyomas in younger women. In these women a *C/*T genotype favors the growth of leiomyomas. [ABSTRACT FROM AUTHOR]

Endometriosis (EMS) is a common gynecological disease characterized by the presence of endometrial tissue outside the uterus. Approximately 10% of women around the world suffer from this disease. Recent studies suggest that endometriosis has potential to transform into endometriosis-associated ovarian cancer (EAOC). Endometriosis is connected with chronic inflammation and changes in the phenotype, activity, and function of immune cells. The underlying mechanisms include quantitative and functional disturbances of neutrophils, monocytes/macrophages (MO/MA), natural killer cells (NK), and T cells. A few reports have shown that immunosuppressive cells such as regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) may promote the progression of endometriosis. MDSCs are a heterogeneous population of immature myeloid cells (dendritic cells, granulocytes, and MO/MA precursors), which play an important role in the development of immunological diseases such as chronic inflammation and cancer. The presence of MDSCs in pathological conditions correlates with immunosuppression, angiogenesis, or release of growth factors and cytokines, which promote progression of these diseases. In this paper, we review the impact of MDSCs on different populations of immune cells, focusing on their immunosuppressive role in the immune system, which may be related with the pathogenesis and/or progression of endometriosis and its transformation into ovarian cancer. [ABSTRACT FROM AUTHOR]

The pulmonary innate immune system is heavily implicated in the perpetual airway inflammation and impaired host defense characterizing Chronic Obstructive Pulmonary Disease (COPD). The airways of patients suffering from COPD are infiltrated by various immune and inflammatory cells including macrophages, neutrophils, T lymphocytes, and dendritic cells. While the role of macrophages, neutrophils and T lymphocytes is well characterized, the contribution of dendritic cells to COPD pathogenesis is still the subject of emerging research. A paper by Botelho and colleagues in the current issue of Respiratory Research investigates the importance of dendritic cell recruitment in cigarette-smoke induced acute and chronic inflammation in mice. Dendritic cells of the healthy lung parenchyma and airways perform an important sentinel function and regulate immune homeostasis. During inflammatory responses the function and migration pattern of these cells is dramatically altered but the underlying mechanisms are incompletely understood. Botelho and colleagues demonstrate here the importance of IL-1R1/IL-1α related mechanisms including CCL20 production in cigarette-smoke induced recruitment of dendritic cells and T cell activation in the mouse lung. [ABSTRACT FROM AUTHOR]