Mice Deficient in Transmembrane Prostatic Acid Phosphatase Display Increased GABAergic Transmission and Neurological Alterations

Peer reviewe

Periderm prevents pathological epithelial adhesions during embryogenesis

Appropriate development of stratified, squamous, keratinizing epithelia, such as the epidermis and oral epithelia, generates an outer protective permeability barrier that prevents water loss, entry of toxins, and microbial invasion. During embryogenesis, the immature ectoderm initially consists of a single layer of undifferentiated, cuboidal epithelial cells that stratifies to produce an outer layer of flattened periderm cells of unknown function. Here, we determined that periderm cells form in a distinct pattern early in embryogenesis, exhibit highly polarized expression of adhesion complexes, and are shed from the outer surface of the embryo late in development. Mice carrying loss-of-function mutations in the genes encoding IFN regulatory factor 6 (IRF6), IκB kinase-α (IKKα), and stratifin (SFN) exhibit abnormal epidermal development, and we determined that mutant animals exhibit dysfunctional periderm formation, resulting in abnormal intracellular adhesions. Furthermore, tissue from a fetus with cocoon syndrome, a lethal disorder that results from a nonsense mutation in IKKA, revealed an absence of periderm. Together, these data indicate that periderm plays a transient but fundamental role during embryogenesis by acting as a protective barrier that prevents pathological adhesion between immature, adhesion-competent epithelia. Furthermore, this study suggests that failure of periderm formation underlies a series of devastating birth defects, including popliteal pterygium syndrome, cocoon syndrome, and Bartsocas-Papas syndrome

Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease

The most severe forms of motoneuron disease manifest in utero are characterized by marked atrophy of spinal cord motoneurons and fetal immobility. Here, we report that the defective gene underlying lethal motoneuron syndrome LCCS1 is the mRNA export mediator GLE1. Our finding of mutated GLE1 exposes a common pathway connecting the genes implicated in LCCS1, LCCS2 and LCCS3 and elucidates mRNA processing as a critical molecular mechanism in motoneuron development and maturation

The colocalization of PAP (green) and GAD65/67 (red) was seen in several areas of brain.

<p>In cerebral Purkinje cells (A–C), strong colocalization was seen especially in the axon hillock of the neuron (small picture in C; yellow color and white arrows depicting the colocalization). Similarly, PAP was present in GABAergic neurons in prefrontal cortex (PFC; infralimbic cortex) (D–F). Scale bars are 10 µm.</p

TMPAP is expressed in the mouse brain and colocalizes with GABAergic marker, GAD 65/67.

<p>Representative confocal images depict intense TMPAP (brown color) expression in molecular cell layer (M) and Purkinje cells (P) of cerebellum (Panel A), in substantia nigra pars reticulata (SNpr; Panel B), in red nucleus (RN; Panel C) and in oculomotor nucleus (O; Panel C). Small picture in Panel B depicts the TMPAP staining of the substantia nigra in PAP<i>^−/−</i> mouse. TMPAP (green) was colocalized with GABAergic marker (red) in medium spiny neurons of striatum (Panels D-G, yellow color and white arrows indicating the colocalization) and in SNpr (Panels H–K). Colocalization was evident also in GABAergic neurons of hippocampus CA1 (Panels L–O). DAPI (blue color) was used as a nuclear marker. Scale bars are 500 µm in Panels A–C, and 10 µm in panels D–O.</p

Immunofluorescent colocalization stainings of TMPAP and synaptic vesicle associated proteins.

<p>TMPAP (green) is colocalized with a presynaptic marker, synaptophysin (red) (A–C; yellow color and white arrows depicting the colocalization). PAP was seen in vesicle-like structures that had strong colocalization with Snapin (D–F). Small picture is a magnification from panel C, depicting the colocalization. Moreover, largest PAP-immunoreactive structures had a colocalization with multivesicular bodies (MVB, red; G–I). All pictures are from striatum. Scale bars are 10 µm in A–C and G–I, and 3 µm in D–F.</p

Immunostaining of Snapin in various brain areas of WT and PAP^−/− mice.

<p>In the PAP^−/− mouse, Snapin (red) is localized more diffusely in the cell soma (B, D, F). Cellular localization of Snapin in WT mouse is more vesicular-like (A, C, E). Scale bar is 10 µm in all figures. M1 - primary motor cortex; SN - substantia nigra.</p

Dopamine synthesis is augmented in the striatum of PAP<i>^−/−</i> mice.

<p>(A) Tissue levels of DA are similar in WT and PAP<i>^−/−</i> mice. (B) Level of the principal metabolite of DA, DOPAC, is elevated in the PAP<i>^−/−</i> mice, and also the DOPAC/DA ratio is elevated (C). (D) Accumulation of L-DOPA is greater in PAP^−/− mice than WT mice 30 min after administration of a blocker of L-amino acid decarboxylase, indicating increased DA synthesis. The data is expressed as mean±S.E.M.; black bars represent WT, grey bars PAP^−/− mice; *<i>p</i><0.05, two tailed t-test (monoamines) or repeated measures ANOVA (microdialysis).</p