Study of pallial neurogenesis in shark embryos and the evolutionary origin of the subventricular zone

The dorsal part of the developing telencephalon is one of the brain areas that has suffered most drastic changes throughout vertebrate evolution. Its evolutionary increase in complexity was thought to be partly achieved by the appearance of a new neurogenic niche in the embryonic subventricular zone (SVZ). Here, a new kind of amplifying progenitors (basal progenitors) expressing Tbr2, undergo a second round of divisions, which is believed to have contributed to the expansion of the neocortex. Accordingly, the existence of a pallial SVZ has been classically considered exclusive of mammals. However, the lack of studies in ancient vertebrates precludes any clear conclusion about the evolutionary origin of the SVZ and the neurogenic mechanisms that rule pallial development. In this work, we explore pallial neurogenesis in a basal vertebrate, the shark Scyliorhinus canicula, through the study of the expression patterns of several neurogenic markers. We found that apical progenitors and radial migration are present in sharks, and therefore, their presence must be highly conserved throughout evolution. Surprisingly, we detected a subventricular band of ScTbr2-expressing cells, some of which also expressed mitotic markers, indicating that the existence of basal progenitors should be considered an ancestral condition rather than a novelty of mammals or amniotes. Finally, we report that the transcriptional program for the specification of glutamatergic pallial cells (Pax6, Tbr2, NeuroD, Tbr1) is also present in sharks. However, the segregation of these markers into different cell types is not clear yet, which may be linked to the lack of layering in anamniotesThis work was supported by the Spanish Ministerio de Economía y Competitividad-FEDER (BFU2014-5863-1P)S

Enriched Monolayer Precursor Cell Cultures from Micro-Dissected Adult Mouse Dentate Gyrus Yield Functional Granule Cell-Like Neurons

BACKGROUND: Stem cell cultures are key tools of basic and applied research in Regenerative Medicine. In the adult mammalian brain, lifelong neurogenesis originating from local precursor cells occurs in the neurogenic regions of the hippocampal dentate gyrus. Despite widespread interest in adult hippocampal neurogenesis and the use of mouse models to study it, no protocol existed for adult murine long-term precursor cell cultures with hippocampus-specific differentiation potential. METHODOLOGY/PRINCIPAL FINDINGS: We describe a new strategy to obtain serum-free monolayer cultures of neural precursor cells from microdissected dentate gyrus of adult mice. Neurons generated from these adherent hippocampal precursor cell cultures expressed the characteristic markers like transcription factor Prox1 and showed the TTX-sensitive sodium currents of mature granule cells in vivo. Similar to granule cells in vivo, treatment with kainic acid or brain derived neurotrophic factor (BDNF) elicited the expression of GABAergic markers, further supporting the correspondence between the in vitro and in vivo phenotype. When plated as single cells (in individual wells) or at lowest density for two to three consecutive generations, a subset of the cells showed self-renewal and gave rise to cells with properties of neurons, astrocytes and oligodendrocytes. The precursor cell fate was sensitive to culture conditions with their phenotype highly influenced by factors within the media (sonic hedgehog, BMP, LIF) and externally applied growth factors (EGF, FGF2, BDNF, and NT3). CONCLUSIONS/SIGNIFICANCE: We report the conditions required to generate adult murine dentate gyrus precursor cell cultures and to analyze functional properties of precursor cells and their differentiated granule cell-like progeny in vitro

The effects of stress on brain and adrenal stem cells

The brain and adrenal are critical control centers that maintain body homeostasis under basal and stress conditions, and orchestrate the body’s response to stress. It is noteworthy that patients with stress-related disorders exhibit increased vulnerability to mental illness, even years after the stress experience, which is able to generate long-term changes in the brain's architecture and function. High levels of glucocorticoids produced by the adrenal cortex of the stressed subject reduce neurogenesis, which contributes to the development of depression. In support of the brain–adrenal connection in stress, many (but not all) depressed patients have alterations in the components of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis, with enlarged adrenal cortex and increased glucocorticoid levels. Other psychiatric disorders, such as post-traumatic stress disorder, bipolar disorder and depression, are also associated with abnormalities in hippocampal volume and hippocampal function. In addition, hippocampal lesions impair the regulation of the LHPA axis in stress response. Our knowledge of the functional connection between stress, brain function and adrenal has been further expanded by two recent, independent papers that elucidate the effects of stress on brain and adrenal stem cells, showing similarities in the way that the progenitor populations of these organs behave under stress, and shedding more light into the potential cellular and molecular mechanisms involved in the adaptation of tissues to stress

Breast Cancer in Pregnancy: report of 12 cases

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Pregnancy after liver transplantation: report of 8 new cases and review of the literature

Improved survival and quality of life following liver transplantation are associated with an increased frequency of pregnancies in liver-transplanted women. We investigated the outcome, complications, and management of those pregnancies. We have reviewed the literature and report 8 pregnancies in 6 transplant recipients. Seven pregnancies were completed at 38+/-2 (mean+/-standard deviation) weeks. One miscarriage occurred at week 12. Newborns' weight averaged 2938+/-156 g. Main complications were preeclampsia (n=1) and reversible cholestasis (n=1). Among 285 pregnancies reported in literature, 78+/-20% were successful and the main complications were: preeclampsia (26+/-19%), hypertension (28+/-19%), reversible liver dysfunction (27+/-21%), cesarean delivery (23+/-10%), preterm birth (31+/-28%), small for gestational age infants (23+/-10%), rejection (10+/-7%). Gestational weeks were 36.7+/-1.3, perinatal mortality was 4+/-10%, malformation rate 3%. The rates of both abortions and complications (preeclampsia and/or hypertension) were inversely related to the time interval between transplantation and conception (p<0.05). Abortions occurred more often in recipients whose underlying disease was autoimmune cirrhosis than in recipients with inherited disorders. Rejection rate was approx. 10%, which appears higher than reported in a non-pregnant population after a comparable time interval from transplant (2-3%). Up to 28 months after delivery, maternal death was 5.5+/-7%. We conclude that: the time intervals between transplantation and conception as well as the original cause of liver failure influence the outcome and complications of pregnancies in liver recipients. However, neonatal survival is high, while malformations are relatively rare

A case of coloboma in a newborn to a woman taking mycophenolate mofetil in pregnancy after kidney transplantation.

Recently, mycophenolate mofetil (MMF) has been introduced in the immunosuppressive strategy after kidney transplantation. Recently, the existence of a MMF associated embriopathy has been hypothesized, namely, multiple craniofacial malformations. Only 1 report has described chorioretinal coloboma. We report a case of woman who used MMF throughout pregnancy after kidney transplantation. Her newborn developed coloboma of the right eye associated with an ocular cyst without any other malformation. The other drugs used by our patient are not considered teratogenic. Therefore, it seems reasonable to conclude a causal relationship between MMF and the malformation observed in this newborn

Generation of a defined and uniform population of CNS progenitors and neurons from mouse embryonic stem cells

A detailed protocol is described allowing the generation of essentially pure populations of glutamatergic neurons from mouse embryonic stem (ES) cells. It is based on the culture of ES cells that are kept undifferentiated by repeated splitting and subsequently amplified as non-adherent cell aggregates. Treatment with retinoic acid causes these ES cells to essentially become neural progenitors with the characteristics of Pax6-positive radial glial cells. As they do in vivo, these progenitors differentiate in glutamatergic pyramidal neurons that form functional synaptic contacts and can be kept in culture for long periods of time. This protocol does not require the use of ES lines expressing resistance or fluorescent markers and can thus be applied in principle to any wild-type or mutant ES line of interest. At least 2 weeks are required from starting ES cell culture until plating progenitors and differentiating neurons establish synaptic transmission within about 10 days