Nuclear Factor \u3baB-Dependent Neurite Remodeling Is Mediated by Notch Pathway

In this study, we evaluated whether a cross talk between nuclear factor \u3baB (NF-\u3baB) and Notch may take place and contribute to regulate cell morphology and/or neuronal network in primary cortical neurons. We found that lack of p50, either induced acutely by inhibiting p50 nuclear translocation or genetically in p50(-/-) mice, results in cortical neurons characterized by reduced neurite branching, loss of varicosities, and Notch1 signaling hyperactivation. The neuronal morphological effects found in p50(-/-) cortical cells were reversed after treatment with the \u3b3-secretase inhibitor DAPT (N-[N-(3,5-difluorophenacetyl)-1-alanyl 1]-S-phenylglycine t-butyl ester) or Notch RNA interference. Together, these data suggested that morphological abnormalities in p50(-/-) cortical neurons were dependent on Notch pathway hyperactivation, with Notch ligand Jagged1 being a major player in mediating such effect. In this line, we demonstrated that the p50 subunit acts as transcriptional repressor of Jagged1. We also found altered distribution of Notch1 and Jagged1 immunoreactivity in the cortex of p50(-/-) mice compared with wild-type littermates at postnatal day 1. These data suggest the relevance of future studies on the role of Notch/NF-\u3baB cross talk in regulating cortex structural plasticity in physiological and pathological conditions

A peculiar formula of essential amino acids prevents rosuvastatin myopathy in mice

Aims: Myopathy, characterized by mitochondrial oxidative stress, occurs in ∼10% of statin-treated patients, and a major risk exists with potent statins such as rosuvastatin (Rvs). We sought to determine whether a peculiar branched-chain amino acid-enriched mixture (BCAAem), found to improve mitochondrial function and reduce oxidative stress in muscle of middle-aged mice, was able to prevent Rvs myopathy. Results: Dietary supplementation of BCAAem was able to prevent the structural and functional alterations of muscle induced by Rvs in young mice. Rvs-increased plasma 3-methylhistidine (a marker of muscular protein degradation) was prevented by BCAAem. This was obtained without changes of Rvs ability to reduce cholesterol and triglyceride levels in blood. Rather, BCAAem promotes de novo protein synthesis and reduces proteolysis in cultured myotubes. Morphological alterations of C2C12 cells induced by statin were counteracted by amino acids, as were the Rvs-increased atrogin-1 mRNA and protein levels. Moreover, BCAAem maintained mitochondrial mass and density and citrate synthase activity in skeletal muscle of Rvs-treated mice beside oxygen consumption and ATP levels in C2C12 cells exposed to statin. Notably, BCAAem assisted Rvs to reduce oxidative stress and to increase the anti-reactive oxygen species (ROS) defense system in skeletal muscle. Innovation and Conclusions: The complex interplay between proteostasis and antioxidant properties may underlie the mechanism by which a specific amino acid formula preserves mitochondrial efficiency and muscle health in Rvs-treated mice. Strategies aimed at promoting protein balance and controlling mitochondrial ROS level may be used as therapeutics for the treatment of muscular diseases involving mitochondrial dysfunction, such as statin myopathy

Neurosphere-Derived Cells Exert a Neuroprotective Action by Changing the Ischemic Microenvironment

BACKGROUND: Neurosphere-derived cells (NC), containing neural stem cells, various progenitors and more differentiated cells, were obtained from newborn C57/BL6 mice and infused in a murine model of focal ischemia with reperfusion to investigate if: 1) they decreased ischemic injury and restored brain function; 2) they induced changes in the environment in which they are infused; 3) changes in brain environment consequent to transient ischemia were relevant for NC action. METHODOLOGY/PRINCIPAL FINDINGS: NC were infused intracerebroventricularly 4 h or 7 d after 30 min middle cerebral artery occlusion. In ischemic mice receiving cells at 4 h, impairment of open field performance was significantly improved and neuronal loss significantly reduced 7–14 d after ischemia compared to controls and to ischemic mice receiving cells at 7 d. Infusion of murine foetal fibroblast in the same experimental conditions was not effective. Assessment of infused cell distribution revealed that they migrated from the ventricle to the parenchyma, progressively decreased in number but they were observable up to 14 d. In mice receiving NC at 7 d and in sham-operated mice, few cells could be observed only at 24 h, indicating that the survival of these cells in brain tissue relates to the ischemic environment. The mRNA expression of trophic factors such as Insulin Growth Factor-1, Vascular Endothelial Growth Factor-A, Transforming Growth Factor-β1, Brain Derived Neurotrophic Factor and Stromal Derived Factor−1α, as well as microglia/macrophage activation, increased 24 h after NC infusion in ischemic mice treated at 4 h compared to sham-operated and to mice receiving cells at 7 d. CONCLUSIONS/SIGNIFICANCE: NC reduce functional impairment and neuronal damage after ischemia/reperfusion injury. Several lines of evidence indicate that the reciprocal interaction between NC and the ischemic environment is crucial for NC protective actions. Based on these results we propose that a bystander control of the ischemic environment may be the mechanism used by NC to rapidly restore acutely injured brain function

NOTCH AND NF-ΚB PATHWAY CROSS-TALK REGULATES NEURITE REMODELLING

5nonenoneSara Anna Bonini; Giulia Ferrari-Toninelli; Daniela Uberti; Mariagrazia Grilli; Maurizio MemoBonini, Sara Anna; FERRARI TONINELLI, Giulia; Uberti, Daniela Letizia; Mariagrazia, Grilli; Memo, Maurizi

Morphology of microglia/macrophages (red).

<p>CD11b immunopositive cells at day 1 after ischemia and NC(4 h) infusion display a round, phagocytic morphology in the injected (A) but not in the contralateral side were no NC are present (B). Microglia/macrophages appear to surround NC as evidenced in C were NC are marked with Hoechst (blue). A further detail of the interaction between these cells is provided in D where one microglia/macrophage appears to cap a NC (marked with 5-CFDA, green). Bar (A–C): 20 µm; bar (D): 7 µm.</p

Box-plot of neuronal count performed in ischemic mice 7 and 14 days after ischemia with the optical dissector method.

<p>Differences of neuronal density between contralateral and ipsilateral striata are sorted by treatment and time. The box represents the median and 25^th–75^th percentiles, whiskers represent the range, + represents the mean of the group. The hierarchical ANOVA showed a significant effect for the treatment (P = 0.02). The Bonferroni post-hoc test showed significant differences (P<0.05) among mean density differences of the isch/NC(4 h) group and the isch/PBS, isch/fibr and isch/NC(7 d) groups. Data plotted have been multiplied by 1×10⁴.</p

Primers used for quantitative real-time polymerase chain reaction analysis of SDF-1α, BDNF, IGF-1, VEGF-A, TGF-β1, β-actin transcript levels.

a<p>forward</p>b<p>reverse</p

Quantification of microglia/macrophage activation.

<p>The area occupied by CD11b immunopositive cells was measured in striatum of sham-operated or ischemic mice receiving PBS, NC(4 h) or NC(7 d) at different time points (see Experimental design, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000373#pone-0000373-g001" target="_blank">Fig. 1A and B</a>). Data are expressed as mean±SEM (n = 4–5). Two-way ANOVA: (A) F: 58.05, p<0.0001; (B) F: 10.19, p = 0.0002. <i>Posthoc</i> Bonferroni test: *p<0.05, **p<0.01, ***p<0.001 vs sham/PBS; °°p<0.01, °°°p<0.001 vs isch/PBS, ##p<0.01, ###p<0.001 vs sham/NC.</p