Stem cell-derived neurons from autistic individuals with SHANK3 mutation show morphogenetic abnormalities during early development.

Shank3 is a structural protein found predominantly at the postsynaptic density. Mutations in the SHANK3 gene have been associated with risk for autism spectrum disorder (ASD). We generated induced pluripotent stem cells (iPSCs) from control individuals and from human donors with ASD carrying microdeletions of SHANK3. In addition, we used Zinc finger nucleases to generate isogenic SHANK3 knockout human embryonic stem (ES) cell lines. We differentiated pluripotent cells into either cortical or olfactory placodal neurons. We show that patient-derived placodal neurons make fewer synapses than control cells. Moreover, patient-derived cells display a developmental phenotype: young postmitotic neurons have smaller cell bodies, more extensively branched neurites, and reduced motility compared with controls. These phenotypes were mimicked by SHANK3-edited ES cells and rescued by transduction with a Shank3 expression construct. This developmental phenotype is not observed in the same iPSC lines differentiated into cortical neurons. Therefore, we suggest that SHANK3 has a critical role in neuronal morphogenesis in placodal neurons and that early defects are associated with ASD-associated mutations.

Unravelling dropsy: from Marcello Malpighi's discovery of the capillaries (1661) to Stephen Hales' production of oedema in an experimental model (1733).

A modern understanding of oedema formation traditionally begins with Starling's description in 1898 of hydrostatic and oncotic forces acting on the capillary membrane. Clearly, hypotheses of oedema formation predating the knowledge of the existence of capillaries must have been incomplete. Marcello Malpighi first described capillaries in 1661, but although he displayed a good grasp of the principles of the Harveian circulation and believed that oedema fluid (the clinical entity dropsy) was derived from the blood rather than the tissues, we have found no evidence that he realised the central role played by his discovery. However, only 60 years later, Stephen Hales' Haemastaticks reveals the creation of an experimental model for dropsy which led him towards an understanding of oedema formation not far behind Starling.

Expression of c-fos in restricted areas of the basal forebrain and brainstem following single or combined intraventricular infusions of vasopressin and corticotropin-releasing factor.

Vasopressin has been shown to be localized in specific central nervous system (CNS) sites. There is considerable evidence that it can act as a central neurotransmitter and it has been ascribed a variety of putative roles in the CNS. To identify those regions of the brain capable of responding to this peptide, 250 pmol vasopressin were infused into the lateral ventricle intracerebroventricular of conscious, handled male rats, and their brains processed for fos-immunohistochemistry 60 min later. Increases in fos-immunoreactivity, compared with cerebrospinal fluid-infused controls, were found in specific regions of the basal forebrain and brainstem: the central nucleus of the amygdala, ventrolateral septum, parvocellular divisions of the paraventricular nucleus of the hypothalamus, dorsal tuberal nucleus and locus coeruleus. Pre-infusion of 2500 pmol of a V1a antagonist prevented or reduced the expression of c-fos by intracerebroventricular vasopressin in all areas except the dorsal parvocellular paraventricular nucleus, implying that in most (but not all) areas the actions of vasopressin are mediated by the V1a receptor. Central administration of vasopressin had no effect on plasma corticosterone levels. Vasopressin and corticotropin-releasing factor act synergistically on the anterior pituitary to cause release of adrenocorticotropic releasing hormone and have corresponding synergistic interactions on behaviour. Infusion of 250 pmol corticotropin releasing factor produced a similar but not identical pattern of fos-like immunoreactivity to that of vasopressin. Activation of the parabrachial nucleus was observed, but there was no significant effect on the lateral septum and apparent increases in the medial parvocellular division of the paraventricular nucleus and locus coeruleus were not significant. Corticotropin releasing factor also caused a marked rise in plasma corticosterone. When the two peptides were infused together (125 pmol each) no evidence for synergy was found, in terms of the number of neurons activated to express c-fos. The induction of differential patterns of fos-like immunoreactivity by vasopressin and corticotropin-releasing factor in specific regions of the limbic forebrain and brainstem has implications for the individual roles they play in the CNS.