Regulation of IL-12p40 by HIF controls Th1/Th17 responses to prevent mucosal inflammation

Intestinal inflammatory lesions are inherently hypoxic, due to increased metabolic demands created by cellular infiltration and proliferation, and reduced oxygen supply due to vascular damage. Hypoxia stabilizes the transcription factor hypoxia-inducible factor-1α (HIF) leading to a coordinated induction of endogenously protective pathways. We identified IL12B as a HIF-regulated gene and aimed to define how the HIF-IL-12p40 axis influenced intestinal inflammation. Intestinal lamina propria lymphocytes (LPL) were characterized in wild-type and IL-12p40^-/- murine colitis treated with vehicle or HIF-stabilizing prolyl-hydroxylase inhibitors (PHDi). IL12B promoter analysis was performed to examine hypoxia-responsive elements. Immunoblot analysis of murine and human LPL supernatants was performed to characterize the HIF/IL-12p40 signaling axis. We observed selective induction of IL-12p40 following PHDi-treatment, concurrent with suppression of Th1 and Th17 responses in murine colitis models. In the absence of IL-12p40, PHDi-treatment was ineffective. Analysis of the IL12B promoter identified canonical HIF-binding sites. HIF stabilization in LPLs resulted in production of IL-12p40 homodimer which was protective against colitis. The selective induction of IL-12p40 by HIF-1α leads to a suppression of mucosal Th1 and Th17 responses. This HIF-IL12p40 axis may represent an endogenously protective mechanism to limit the progression of chronic inflammation, shifting from pro-inflammatory IL-12p70 to an antagonistic IL-12p40 homodimer.

Targeting translational control as a novel way to treat inflammatory disease: the emerging role of microRNAs

Chronic inflammatory diseases (e.g. asthma and chronic obstructive pulmonary disease)are leading causes of morbidity and mortality world-wide and effective treatments are limited. These disorders can often be attributed to abnormal immune responses to environmental stimuli and infections. Mechanisms leading to inflammation are complex,resulting from interactions of structural cells and activation of both the adaptive and innate arms of the immune system. The activation of structural and immune cells involves both temporary and permanent changes in gene expression in these cells, which underpin chronic inflammation and tissue dysfunction. miRNAs are small non-coding RNAs increasingly being recognized to play important roles in the post-transcriptional regulation of gene expression in mammalian cells by regulating translation. Individual miRNA scan exert their effects by directly inhibiting the translation or stability of multiple mRNAs simultaneously. Thus, the expression or blockade of function of a single miRNA (miR) can result in pronounced alterations in protein expression within a given cell. Dysregulation of miRNA expression may subsequently alter cellular function, and in certain situations predispose to disease. Our current understanding of the role of miRNA in the regulation of inflammatory disease (e.g. allergic diseases) remains limited. In this review, we provide an overview of the current understanding of miRNA biogenesis and function, the roles miRNA play in the regulation of immune cell function and their potential contribution to inflammatory diseases. We also highlight strategies to alter miRNA function for experimental or therapeutic gain, and discuss the potential utility and limitations of targeting these molecules as anti-inflammatory strategies.

Different patterns of integral membrane protein localization during cell division in Bacillus subtilis

Cell division in rod-shaped bacteria nearly always occurs exactly at mid-cell and is dependent on the formation of the cytokinetic FtsZ ring and its associated division proteins. Many thousands of copies of division, or septum-specific proteins assemble at this site and may lead to the exclusion of other integral membrane proteins that are normally able to diffuse freely throughout the cytoplasmic membrane. In this study we have investigated the localization of a series of integral membrane proteins in Bacillus subtilis and we show that the recruitment of division and septum-specific proteins does not necessarily preclude the diffusion of other integral membrane proteins. However, some proteins, namely ATP synthase and succinate dehydrogenase, are reduced/absent from the mid-cell region at the onset of cell division, which may reflect an association with lipid domains rich in phosphatidylglycerol that are thought to be present at diminished levels at sites of cell division.

[Significance of the preoperative status in the evaluation of results of the reconstruction of extensor tendons]

Since 1977, a new evaluation scheme that is simple to use and which provides more objective information than earlier plans has been employed for the assessment of the results of extensor tendon reconstruction. The results in the four groups were evaluated and given a prognosis in accordance with the newly developed scheme. This permitted not only a better differentiation of the value of the therapeutic procedures, but also allowed one to make prognostic predictions. The prognosis is also of particular importance during preoperative talks with the patient.