Sstr2A: a relevant target for the delivery of genes into human glioblastoma cells using fiber-modified adenoviral vectors.

Glioblastomas are the most aggressive of the brain tumors occurring in adults and children. Currently available chemotherapy prolongs the median survival time of patients by only 4 months. The low efficiency of current treatments is partly owing to the blood-brain barrier, which restricts the penetration of most drugs into the central nervous system.

Doxorubicin-induced cardiac dysfunction is attenuated by ciclosporin treatment in mice through improvements in mitochondrial bioenergetics.

We tested whether inhibition of mitochondrial membrane potential dissipation by CsA (ciclosporin A) would prevent doxorubicin-induced myocardial and mitochondrial dysfunction. Acute and subchronic models of doxorubicin exposition were performed in mice with either a single intraperitoneal bolus (10 mg/kg of body weight, intraperitoneal) or one injection of 4 mg·kg(-1) of body weight·week(-1) during 5 weeks. Follow-up was at 1.

Influence of chimeric human-bovine fibers on adenoviral uptake by liver cells and the antiviral immune response.

Human adenoviruses (HAdV) are widely used for in vitro and in vivo gene transfer. Viral hepatotropism, inflammatory responses and neutralization by pre-existing antibodies (NAbs) are obstacles for clinical applications of HAdV vectors. Although the multifactorial events leading to innate HAdV toxicity are far from being elucidated, there is a consensus that the majority of intravenously injected-HAdV vectors is sequestered by Kuppfer cells, probably independently of coagulation factors.

Role of estradiol in the dynamic control of tanycyte plasticity mediated by vascular endothelial cells in the median eminence.

In the ever-changing physiological context of the neuroendocrine brain, the mechanisms by which cellular events involving neurons, astroglia, and vascular cells are coordinated to bring forth the appropriate neuronal signaling is not yet known but is amenable to examination. In the median eminence of the hypothalamus, endothelial cells are key players in the plasticity of tanycytes (specialized astroglia) and neuroendocrine synapse efficacy. Here we report that estradiol acts on both purified endothelial cells and isolated tanycytes to trigger endothelial-to-glial communication that leads to a sudden and massive retraction of tanycyte processes.

Two-dimensional electrophoresis of tau mutants reveals specific phosphorylation pattern likely linked to early tau conformational changes.

The role of Tau phosphorylation in neurofibrillary degeneration linked to Alzheimer's disease remains to be established. While transgenic mice based on FTDP-17 Tau mutations recapitulate hallmarks of neurofibrillary degeneration, cell models could be helpful for exploratory studies on molecular mechanisms underlying Tau pathology. Here, "human neuronal cell lines" overexpressing Wild Type or mutated Tau were established.

Activation of neuronal nitric oxide release inhibits spontaneous firing in adult gonadotropin-releasing hormone neurons: a possible local synchronizing signal.

The activation of nitric oxide (NO) signaling pathways in hypothalamic neurons plays a key role in the control of GnRH secretion that is central to reproductive function. It is unknown whether NO directly modulates the firing behavior of GnRH neurons in the preoptic region of the mature brain. Using patch-clamp recordings from GnRH neurons expressing green fluorescent protein in adult mice brain slices, we demonstrate that the NO precursor, L-arginine (Arg), or the NO donor, diethylamine/NO, induced a robust and reversible reduction in the spontaneous firing activity of GnRH neurons, including bursting activity.

Intracellular trafficking of a fiber-modified adenovirus using lipid raft/caveolae endocytosis.

Most adenoviral vectors (HAdvs) elaborated for gene therapy are derived from serotype 5 viruses that use clathrin-coated vesicle endocytosis for cell entry. However, it appears that adenoviral vectors are able to take advantage of lipid raft/caveolae endocytosis to infect cells. In vivo targeting of a therapeutic gene to specific cells by vector engineering has become a major focus of gene therapy research.

Morphological evidence for direct interaction between gonadotrophin-releasing hormone neurones and astroglial cells in the human hypothalamus.

In rodents, there is compelling evidence indicating that dynamic cell-to-cell communications involving cross talk between astroglial cells (such as astrocytes and specialised ependymoglial cells known as tanycytes) and neurones are important in regulating the secretion of gonadotrophin-releasing hormone (GnRH), the neurohormone that controls both sexual maturation and adult reproductive function. However, whether such astroglial cell-GnRH neurone interactions occur in the human brain is not known. In the present study, we used immunofluorescence to examine the anatomical relationship between GnRH neurones and glial cells within the hypothalamus of five women.

Neuronal-glial-endothelial interactions and cell plasticity in the postnatal hypothalamus: implications for the neuroendocrine control of reproduction.

It is becoming increasingly apparent that non-neuronal cells play a critical role in generating and regulating the flow of information within the brain. Among these non-neuronal cells, astroglial cells have been shown to play important roles in the control of both synaptic transmission and neurosecretion. In addition to modulating neuronal activity, astroglial cells interact with endothelial cells throughout the central nervous system to define specific functional domains.

Coupling of neuronal nitric oxide synthase to NMDA receptors via postsynaptic density-95 depends on estrogen and contributes to the central control of adult female reproduction.

Considerable research has been devoted to the understanding of how nitric oxide (NO) influences brain function. Few studies, however, have addressed how its production is physiologically regulated. Here, we report that protein-protein interactions between neuronal NO synthase (nNOS) and glutamate NMDA receptors via the scaffolding protein postsynaptic density-95 (PSD-95) in the hypothalamic preoptic region of adult female rats is sensitive to cyclic estrogen fluctuation.

Alkalizing drugs induce accumulation of amyloid precursor protein by-products in luminal vesicles of multivesicular bodies.

Amyloid precursor protein (APP) metabolism is central to the pathogenesis of Alzheimer disease. We showed recently that the amyloid intracellular domain (AICD), which is released by gamma-secretase cleavage of APP C-terminal fragments (CTFs), is strongly increased in cells treated with alkalizing drugs (Vingtdeux, V., Hamdane, M.

Intracellular pH regulates amyloid precursor protein intracellular domain accumulation.

The amyloid precursor protein (APP) metabolism is central to pathogenesis of Alzheimer's disease (AD). Parenchymal amyloid deposits, a neuropathological hallmark of AD, are composed of amyloid-beta peptides (Abeta). Abeta derives from the amyloid precursor protein (APP) by sequential cleavages by beta- and gamma-secretases.

Anatomical distribution and biochemical characterization of the novel RFamide peptide 26RFa in the human hypothalamus and spinal cord.

26RFa is a novel RFamide peptide originally isolated in the amphibian brain. The 26RFa precursor has been subsequently characterized in various mammalian species but, until now, the anatomical distribution and the molecular forms of 26RFa produced in the CNS of mammals, in particular in human, are unknown. In the present study, we have investigated the localization and the biochemical characteristics of 26RFa-like immunoreactivity (LI) in two regions of the human CNS--the hypothalamus and the spinal cord.

Cancer cell mitochondria are direct proapoptotic targets for the marine antitumor drug lamellarin D.

Lamellarin D is a marine alkaloid with a pronounced cytotoxicity against a large panel of cancer cell lines and is a potent inhibitor of topoisomerase I. However, lamellarin D maintains a marked cytotoxicity toward cell lines resistant to the reference topoisomerase I poison camptothecin. We therefore hypothesized that topoisomerase I is not the only cellular target for the drug.

Structure and functions of the novel hypothalamic RFamide neuropeptides R-RFa and 26RFa in vertebrates.

A number of RFamide peptides have been characterized in invertebrate species and these peptides have been found to exert a broad spectrum of biological activities. In contrast, in vertebrates, our knowledge on RFamide peptides is far more limited and only a few members of the RFamide peptide family have been identified in various vertebrate classes during the last years. The present review focuses on two novel RFamide peptides, Rana RFamide (R-RFa) and 26RFa, that have been recently isolated from the amphibian brain.

Regions of tau implicated in the paired helical fragment core as defined by NMR.

We have studied the mature Alzheimer-like fibers of tau by fluorescence and NMR spectroscopy. Assembly of the protein into paired helical filaments after incubation with heparin at 37 degrees C was verified by electron microscopy and size-exclusion chromatography. NMR spectroscopy on these mature fibers revealed different regions of residual mobility for tau: the N-terminal domain was found to maintain solution-like dynamics and was followed by a large domain of decreasing mobility; finally the core region was distinguished by a solid-like character.

Induction of apoptosis-like mitochondrial impairment triggers antioxidant and Bcl-2-dependent keratinocyte differentiation.

Terminally differentiated keratinocytes are dead enucleated squams. We showed previously that the mitochondria-dependent cell death pathway might be gradually activated as differentiation progresses. In this study, we demonstrated that protoporphyrin IX, staurosporine, and rotenone induced apoptotic-like changes in the mitochondria, and early differentiation of keratinocytes without inducing apoptosis.

Vascular endothelial cells promote acute plasticity in ependymoglial cells of the neuroendocrine brain.

Glial and endothelial cells interact throughout the brain to define specific functional domains. Whether endothelial cells convey signals to glia in the mature brain is unknown but is amenable to examination in circumventricular organs. Here we report that purified endothelial cells of one of these organs, the median eminence of the hypothalamus, induce acute actin cytoskeleton remodeling in isolated ependymoglial cells and show that this plasticity is mediated by nitric oxide (NO), a diffusible factor.

Biochemical characterization and immunohistochemical localization of urotensin II in the human brainstem and spinal cord.

The human urotensin II (UII) precursor encompasses several potential cleavage sites and thus, processing of pro-UII may generate various forms of mature UII including the peptides of 11 (UII11), 16 (UII16) and 19 (UII19) residues. Until now, the native form of human UII had not been characterized. Here, we show that the major UII peptide occurring in the human spinal cord corresponds to UII11.

Mitochondrial proliferation during apoptosis induced by anticancer agents: effects of doxorubicin and mitoxantrone on cancer and cardiac cells.

Doxorubicin is one of the most largely prescribed antitumor drug for the treatment of breast, liver and colon cancers as well as leukemia, but the cardiotoxicity of this anthracycline derivative limits its clinical use. Although doxorubicin is toxic to both cancer and cardiac cells, there are evidences suggesting that the mechanism of cell death is different for the two cell types. To investigate further this issue, we have compared the proapoptotic effects of doxorubicin and the functionally related anthracenedione compound mitoxantrone, which is also used in the clinic for the treatment of cancer.

[Hypothalamic glial cells and endothelial cells as key regulators of GnRH secretion].

During the last decade, compelling evidence has been provided that, in addition of being regulated by transsynaptic inputs, GnRH neuroendocrine secretion is modulated by factors released both by glial cells and the endothelium of pituitary portal blood vessels. Glial cells exert their regulatory influence on GnRH release through the secretion of growth factors, such as TGFbetas and peptides member of the EGF family, that act either directly on GnRH neurons or require prostaglandin release from astrocytes, respectively. On the other hand vascular endothelial cells stimulate GnRH release via NO secretion.

Regulation of galanin receptor GalR1 mRNA expression by ovarian steroids in oestrogen receptor alpha-immunoreactive neurones: identification of distinct populations of neurones in the preoptic area.

This study examined whether gonadal steroids are involved in regulating galanin receptor 1 (GalR1) mRNA expression in neurones that contain oestrogen receptor alpha (ERalpha), in three regions of the preoptic area (POA) known to be involved in the control of gonadotropin secretion. Double-labelling immunohistochemistry using an antibody against the ERalpha and in situ hybridization experiments using a 35S-labelled riboprobe specific for GalR1 mRNAs revealed that ERalpha is expressed in a large proportion of GalR1 mRNA-expressing neurones of the POA in the ovariectomized (OVX) female rat. Oestradiol (E2) and oestradiol plus progesterone (E2 + P) treatments of OVX rats significantly decreased the proportion of GalR1 mRNA/ERalpha immunoreactive (ERalpha-IR) neurones in the anteroventral periventricular nucleus (AVPV), medial preoptic nucleus (MPN) and medial preoptic area (MPO).

Transforming growth factor beta1 may directly influence gonadotropin-releasing hormone gene expression in the rat hypothalamus.

In vitro studies using immortalized GT1 cells suggest that hypothalamic astrocytes employ TGFbeta(1) to directly regulate the secretion of GnRH, the neurohormone that controls sexual maturation and adult reproductive function. However, whether such astrocyte-GnRH neuron signaling occurs in vivo is not clear. In the present study, we used in situ hybridization and immunohistochemistry to determine whether astrocytes and GnRH neurons express the molecular components necessary to set in motion communication processes involving TGFbeta(1) signaling.

Identification of 26RFa, a hypothalamic neuropeptide of the RFamide peptide family with orexigenic activity.

A neuropeptide was isolated from a frog brain extract by HPLC purification and characterized by mass spectrometry. This 26-aa neuropeptide, which belongs to the RFamide peptide family, was designated 26RFa, and its primary structure was established as VGTALGSLAEELNGYNRKKGGFSFRF-NH2. Research in databases revealed the presence of sequences homologous to frog 26RFa in the human genome and in rat ESTs.

A confocal microscopic study of gonadotropin-releasing hormone (GnRH) neuron inputs to dopaminergic neurons containing estrogen receptor alpha in the arcuate nucleus of GnRH-green fluorescent protein transgenic mice.

The purpose of the present study was to determine whether the septo-preoptico-tuberoinfundibular gonadotropin-releasing hormone (GnRH) pathway comes in close juxtaposition with tyrosine hydroxylase immunoreactive (TH-IR) neurons in the arcuate nucleus of female mice. Immunohistochemical staining with a TH monoclonal antibody coupled with confocal microscopy was employed on vibratome-cut brain sections of female GnRH-green fluorescent protein (GFP) transgenic mice to evaluate possible appositions between GnRH and tuberoinfundibular dopaminergic (TIDA) neurons. TH-IR neurons of the arcuate nucleus received GnRH neuronal appositions in adult female mice at proestrus and estrus stages.