IL-4 induces cAMP and cGMP in human monocytic cells

Human monocytes, preincubated with IFN-γ respond to IL-4 by a cGMP increase through activation of an inducible NO synthase. Here, IL-4 was found to induce an accumulation of cGMP (1 – 3 min) and cAMP (20 – 25 min) in unstimulated monocytes. This was impaired with NOS inhibitors, but also with EGTA and calcium/calmodulin inhibitors. These results suggest that: (1) IL-4 may stimulate different NOS isoforms in resting and IFN-γ activated monocytes, and (2) cAMP accumulation may be partially dependent on the NO pathway. By RT-PCR, a type III constitutive NOS mRNA was detected in U937 monocytic cells. IL-4 also increased the [Ca2+]i in these cells. Different NOS may thus be expressed in monocytic cells depending on their differentiation and the signals they receive

Adult Body Weight Is Programmed by a Redox-Regulated and Energy-Dependent Process during the Pronuclear Stage in Mouse

In mammals fertilization triggers a series of Ca2+ oscillations that not only are essential for events of egg activation but also stimulate oxidative phosphorylation. Little is known, however, about the relationship between quantitative changes in egg metabolism and specific long-term effects in offspring. This study assessed whether post-natal growth is modulated by early transient changes in NAD(P)H and FAD2+ in zygotes. We report that experimentally manipulating the redox potential of fertilized eggs during the pronuclear (PN) stage affects post-natal body weight. Exogenous pyruvate induces NAD(P)H oxidation and stimulates mitochondrial activity with resulting offspring that are persistently and significantly smaller than controls. Exogenous lactate stimulates NAD+ reduction and impairs mitochondrial activity, and produces offspring that are smaller than controls at weaning but catch up after weaning. Cytosolic alkalization increases NAD(P)+ reduction and offspring of normal birth-weight become significantly and persistently larger than controls. These results constitute the first report that post-natal growth rate is ultimately linked to modulation of NAD(P)H and FAD2+ concentration as early as the PN stage

Asymmetrical DNA and AT/GC base content of differential sector of Pleurodeles waltl sexual bivalent: a quantitative fluorescence imaging analysis in lamprush chromosomes

International audienc

Intracellular pH in one-cell mouse embryo differs between subcellular compartments and between interphase and mitosis

International audienc

Photofrin-induced fluorescence in progressive and regressive murine colonic cancer cells : correlation with cell photosensitivity

International audienc

Three distinct sub-nuclear populations of HMG-I protein of different properties revealed by co-localization image analysis.

We have studied the nuclear distribution of the non-histone HMG-I protein by indirect immunofluorescence in several human and murine somatic cell lines and in growing mouse oocytes. We show that HMG-I, a high mobility-group protein which interacts in vitro with the minor groove of AT-rich B-DNA, is found exclusively in the nucleus and that this localization corresponds to a complex distribution. By comparing the HMG-I-dependent fluorescence signal with the chromatin density determined by Hoechst 33342 or propidium iodide staining, we present evidence for the existence of three HMG-I sub-populations whose contribution to the total fluorescence can be determined using a newly developed quantitative co-localization image analysis program: foci that correspond to regions of heterochromatin, intense dots located within decondensed chromatin, and a more diffuse component extending throughout the nucleoplasm. In addition, we show that these sub-populations differ in their sensitivity to nuclease digestion and in vivo displacement by the minor-groove binder Hoechst 33342. Finally, double immunolabeling of RNA polymerase II-dependent transcription and HMG-I shows that the intense dots are not correlated with sites of high transcriptional activity. We discuss the possibility that these three sub-populations reflect distinct and separable biological functions of the HMG-I protein