High-resolution ultrasound and speckle tracking: a non-invasive approach to assess in vivo gastrointestinal motility during development.

Gastrointestinal motor activity has been extensively studied in adults; however, only few studies have investigated fetal motor skills. It is unknown when the gastrointestinal tract starts to contract during the embryonic period and how this function evolves during development. Here, we adapted a non-invasive high-resolution echography technique combined with speckle tracking analysis to examine the gastrointestinal tract motor activity dynamics during chick embryo development.

PROX1 is a specific and dynamic marker of sacral neural crest cells in the chicken intestine.

The enteric nervous system (ENS) is a complex network constituted of neurons and glial cells that ensures the intrinsic innervation of the gastrointestinal tract. ENS cells originate from vagal and sacral neural crest cells that are initially located at the border of the neural tube. In birds, sacral neural crest cells (sNCCs) first give rise to an extramural ganglionated structure (the so-called Nerve of Remak [NoR]) and to the pelvic plexus.

Colonic mesenchyme differentiates into smooth muscle before its colonization by vagal enteric neural crest-derived cells in the chick embryo.

During development, the gastrointestinal (GI) tract arises from a primary tube composed of mesoderm and endoderm. The mesoderm gives rise to the digestive mesenchyme, which in turn differentiates into multiple tissues, namely the submucosa, the interstitial cells of Cajal and the smooth muscle cells (SMCs). Concomitant with these early patterning events, the primitive GI tract is colonized by vagal enteric neural crest-derived cells (vENCDCs), a population of cells that gives rise to the enteric nervous system, the intrinsic innervation of the GI tract.

Complementary actions of dopamine D2 receptor agonist and anti-vegf therapy on tumoral vessel normalization in a transgenic mouse model.

Angiogenesis contributes in multiple ways to disease progression in tumors and reduces treatment efficiency. Molecular therapies targeting Vegf signaling combined with chemotherapy or other drugs exhibit promising results to improve efficacy of treatment. Dopamine has been recently proposed to be a novel safe anti-angiogenic drug that stabilizes abnormal blood vessels and increases therapeutic efficacy.

OCAM regulates embryonic spinal cord stem cell proliferation by modulating ErbB2 receptor.

The proliferation and differentiation of neural stem cells are tightly controlled by intrinsic and extrinsic cues. Cell adhesion molecules are increasingly recognized as regulators of these processes. Here we report the expression of the olfactory cell adhesion molecule (OCAM/NCAM2/RNCAM) during mouse spinal cord development and in neural stem cells cultured as neurospheres.

Sustained alterations of hypothalamic tanycytes during posttraumatic hypopituitarism in male mice.

Traumatic brain injury is a leading cause of hypopituitarism, which compromises patients' recovery, quality of life, and life span. To date, there are no means other than standardized animal studies to provide insights into the mechanisms of posttraumatic hypopituitarism. We have found that GH levels were impaired after inducing a controlled cortical impact (CCI) in mice.

Related pituitary cell lineages develop into interdigitated 3D cell networks.

The pituitary gland has long been considered to be a random patchwork of hormone-producing cells. By using pituitary-scale tridimensional imaging for two of the least abundant cell lineages, the corticotropes and gonadotropes, we have now uncovered highly organized and interdigitated cell networks that reflect homotypic and heterotypic interactions between cells. Although newly differentiated corticotrope cells appear on the ventral surface of the gland, they rapidly form homotypic strands of cells that extend from the lateral tips of the anterior pituitary along its ventral surface and into the medial gland.

Different degrees of somatotroph ablation compromise pituitary growth hormone cell network structure and other pituitary endocrine cell types.

We have generated transgenic mice with somatotroph-specific expression of a modified influenza virus ion channel, (H37A)M2, leading to ablation of GH cells with three levels of severity, dependent on transgene copy number. GH-M2(low) mice grow normally and have normal-size pituitaries but 40-50% reduction in pituitary GH content in adult animals. GH-M2(med) mice have male-specific transient growth retardation and a reduction in pituitary GH content by 75% at 42 d and 97% by 100 d.

Characterization of adherens junction protein expression and localization in pituitary cell networks.

Our view of anterior pituitary organization has been altered with the recognition that folliculo-stellate (FS) and somatotroph cell populations form large-scale three-dimensional homotypic networks. This morphological cellular organization may optimize communication within the pituitary gland promoting coordinated pulsatile secretion adapted to physiological needs. The aim of this study was to identify the molecules involved in the formation and potential functional organization and/or signaling within these cell-cell networks.

The circadian clock components CRY1 and CRY2 are necessary to sustain sex dimorphism in mouse liver metabolism.

In mammals, males and females exhibit anatomical, hormonal, and metabolic differences. A major example of such sex dimorphism in mouse involves hepatic drug metabolism, which is also a noticeable target of circadian timekeeping. However, whether the circadian clock itself contributes to sex-biased metabolism has remained unknown, although several daily output parameters differ between sexes in a number of species, including humans.

Assembly of the N-cadherin complex during synapse formation involves uncoupling of p120-catenin and association with presenilin 1.

N-cadherin is an adhesion receptor that participates in both interaction between immature pre- and postsynaptic neurons and in the stabilization and function of matured neuron-neuron synapses. To better understand how the N-cadherin complex contributes to synapse formation, we examined its distribution and composition during synapse formation in the chick ciliary neurons. It was found that at early phases of synaptogenesis, N-cadherin is distributed in small clusters on the cell surface and primarily associates with p120-catenin and 3-catenin.

Assembly of the N-cadherin complex during synapse formation involves uncoupling of p120-catenin and association with presenilin 1.

N-cadherin is an adhesion receptor that participates in both interaction between immature pre- and postsynaptic neurons and in the stabilization and function of matured neuron-neuron synapses. To better understand how the N-cadherin complex contributes to synapse formation, we examined its distribution and composition during synapse formation in the chick ciliary neurons. It was found that at early phases of synaptogenesis, N-cadherin is distributed in small clusters on the cell surface and primarily associates with p120-catenin and beta-catenin.

Differential expression of p120 catenin in glial cells of the adult rat brain.

p120 catenin (p120ctn) is involved in the regulation of cadherin-mediated adhesion and the dynamic organization of the actin cytoskeleton by modulating RhoGTPase activity. We have previously described the distribution of p120ctn during rat brain development and provided substantial evidence for the potential involvement of p120ctn in morphogenetic events and plasticity in the central nervous system. Here, we analyzed the cellular and ultrastructural distribution of p120ctn in glial cells of the adult rat forebrain.

Distribution of p120 catenin during rat brain development: potential role in regulation of cadherin-mediated adhesion and actin cytoskeleton organization.

p120 catenin (p120ctn) is implicated in the regulation of cadherin-mediated adhesion and actin cytoskeleton remodeling. The interaction of cytoplasmic p120ctn with the guanine exchange factor Vav2 is one of the signaling pathways implicated in cytoskeleton dynamics. We show here that p120ctn is regulated during rat brain development and is distributed at the membrane and within the cytoplasm where it associates with N-cadherin and Vav2, respectively.

Polysialic acid and the formation of oculomotor synapses on chick ciliary neurons.

The polysialic acid (PSA) moiety of the neural cell adhesion molecule (NCAM) participates in a variety of developmental processes, including axonal guidance and cell migration. PSA's function in these contexts stems from its ability to reduce cell interactions. The present study examines the regulation of PSA expression during formation of the calyciform synapse by the oculomotor axons on chick ciliary neurons.