Publications by authors named "Johanna Tahvanainen"

The differentiation of human primary T helper 1 (Th1) cells from naïve precursor cells is regulated by a complex, interrelated signaling network. The identification of factors regulating the early steps of Th1 cell polarization can provide important insight in the development of therapeutics for many inflammatory and autoimmune diseases. The serine/threonine-specific proviral integration site for Moloney murine leukemia virus (PIM) kinases PIM1 and PIM2 have been implicated in the cytokine-dependent proliferation and survival of lymphocytes.

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Dissecting the molecular mechanisms by which T helper (Th) cells differentiate to effector Th2 cells is important for understanding the pathogenesis of immune-mediated diseases, such as asthma and allergy. Because the STAT6 transcription factor is an upstream mediator required for interleukin-4 (IL-4)-induced Th2 cell differentiation, its targets include genes important for this process. Using primary human CD4(+) T cells, and by blocking STAT6 with RNAi, we identified a number of direct and indirect targets of STAT6 with ChIP sequencing.

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The identification of novel factors regulating human T helper (Th)-cell differentiation into functionally distinct Th1 and Th2 subsets is important for understanding the mechanisms behind human autoimmune and allergic diseases. We have identified a protein of relevant evolutionary and lymphoid interest (PRELI), a novel protein that induces oxidative stress and a mitochondrial apoptosis pathway in human primary Th cells. We also demonstrated that PRELI inhibits Th2-cell development and down-regulates signal transducer and activator of transcription 6 (STAT6), a key transcription factor driving Th2 differentiation.

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Th cell subtypes, Th1 and Th2, are involved in the pathogenesis or progression of many immune-mediated diseases, such as type 1 diabetes and asthma, respectively. Defining the molecular networks and factors that direct Th1 and Th2 cell differentiation will help to understand the pathogenic mechanisms causing these diseases. Some of the key factors regulating this differentiation have been identified, however, they alone do not explain the process in detail.

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Identification of key factors mediating the differentiation of naïve CD4(+) T helper cells into Th1 and Th2 subsets is important for understanding the molecular mechanisms of the development of autoimmune diseases as well as asthma and allergy. Functional importance of a given gene in the initiation of human T helper cell differentiation has been hard to study due to the difficulty in transfecting primary resting human T lymphocytes. In this study we have successfully transfected human primary CD4(+) T helper cells using Amaxa's Nucleofection technology.

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