Reversing behavioural abnormalities in mice exposed to maternal inflammation

Viral infection during pregnancy is correlated with increased frequency of neurodevelopmental disorders, and this is studied in mice prenatally subjected to maternal immune activation (MIA). We previously showed that maternal T helper 17 cells promote the development of cortical and behavioural abnormalities in MIA-affected offspring. Here we show that cortical abnormalities are preferentially localized to a region encompassing the dysgranular zone of the primary somatosensory cortex (S1DZ). Moreover, activation of pyramidal neurons in this cortical region was sufficient to induce MIA-associated behavioural phenotypes in wild-type animals, whereas reduction in neural activity rescued the behavioural abnormalities in MIA-affected offspring. Sociability and repetitive behavioural phenotypes could be selectively modulated according to the efferent targets of S1DZ. Our work identifies a cortical region primarily, if not exclusively, centred on the S1DZ as the major node of a neural network that mediates behavioural abnormalities observed in offspring exposed to maternal inflammation.

An Autism-Linked Mutation Disables Phosphorylation Control of UBE3A

Deletion of UBE3A causes the neurodevelopmental disorder Angelman syndrome (AS), while duplication or triplication of UBE3A is linked to autism. These genetic findings suggest that the ubiquitin ligase activity of UBE3A must be tightly maintained to promote normal brain development. Here, we found that protein kinase A (PKA) phosphorylates UBE3A in a region outside of the catalytic domain at residue T485 and inhibits UBE3A activity toward itself and other substrates. A de novo autism-linked missense mutation disrupts this phosphorylation site, causing enhanced UBE3A activity in vitro, enhanced substrate turnover in patient-derived cells, and excessive dendritic spine development in the brain. Our study identifies PKA as an upstream regulator of UBE3A activity and shows that an autism-linked mutation disrupts this phosphorylation control. Moreover, our findings implicate excessive UBE3A activity and the resulting synaptic dysfunction to autism pathogenesis.

Snx14 regulates neuronal excitability, promotes synaptic transmission, and is imprinted in the brain of mice

Genomic imprinting describes an epigenetic process through which genes can be expressed in a parent-of-origin-specific manner. The monoallelic expression of imprinted genes renders them particularly susceptible to disease causing mutations. A large proportion of imprinted genes are expressed in the brain, but little is known about their functions. Indeed, it has proven difficult to identify cell type-specific imprinted genes due to the heterogeneity of cell types within the brain. Here we used laser capture microdissection of visual cortical neurons and found evidence that sorting nexin 14 (Snx14) is a neuronally imprinted gene in mice. SNX14 protein levels are high in the brain and progressively increase during neuronal development and maturation. Snx14 knockdown reduces intrinsic excitability and severely impairs both excitatory and inhibitory synaptic transmission. These data reveal a role for monoallelic Snx14 expression in maintaining normal neuronal excitability and synaptic transmission.

Synaptic dysfunction and abnormal behaviors in mice lacking major isoforms of Shank3

SHANK3 is a synaptic scaffolding protein enriched in the postsynaptic density (PSD) of excitatory synapses. Small microdeletions and point mutations in SHANK3 have been identified in a small subgroup of individuals with autism spectrum disorder (ASD) and intellectual disability. SHANK3 also plays a key role in the chromosome 22q13.3 microdeletion syndrome (Phelan-McDermid syndrome), which includes ASD and cognitive dysfunction as major clinical features. To evaluate the role of Shank3 in vivo, we disrupted major isoforms of the gene in mice by deleting exons 4-9. Isoform-specific Shank3(e4-9) homozygous mutant mice display abnormal social behaviors, communication patterns, repetitive behaviors and learning and memory. Shank3(e4-9) male mice display more severe impairments than females in motor coordination. Shank3(e4-9) mice have reduced levels of Homer1b/c, GKAP and GluA1 at the PSD, and show attenuated activity-dependent redistribution of GluA1-containing AMPA receptors. Subtle morphological alterations in dendritic spines are also observed. Although synaptic transmission is normal in CA1 hippocampus, long-term potentiation is deficient in Shank3(e4-9) mice. We conclude that loss of major Shank3 species produces biochemical, cellular and morphological changes, leading to behavioral abnormalities in mice that bear similarities to human ASD patients with SHANK3 mutations.

Intracellular Ca2+ homeostasis in rat round spermatids

Intracellular calcium, [Ca2+]i, can regulate meiotic progression of mammalian oocytes. However, the role of [Ca2+]i in the regulation of the spermatogenic process and its cellular homeostatic mechanisms in spermatogenic cells has not been elucidated. Using intracellular fluorescent probes for Ca2+ and immunodetection of plasma membrane (PM) Ca(2+)-ATPases, we report that: a) rat round spermatids maintain [Ca2+]i levels of 60 +/- 5 nM (SEM), as estimated with fluo-3 in single cells or fura-2 in cells in suspension; b) these cells regulate [Ca2+]i by actively extruding it using a PM Ca(2+)-ATPase; c) rat spermatids also actively transport Ca2+ by sarco-endoplasmic reticulum type ATPases (SERCA); d) rat spermatids possess non-mitochondrial intracellular Ca2+i stores insensitive to thapsigargin but releasable by ionomycin; and e) rat spermatids do not activate Ca2+ entry mechanisms by the release of Ca2+ from SERCA-regulated stores. These results demonstrate that rat round spermatids can generate modulated intracellular Ca2+ signals upon activation of Ca2+ channels or Ca2+ release from intracellular stores.

[The prevalence of giardiasis in patients who undergo gastroduodenoscopy]

Giardiasis constitutes a very frequent intestinal parasitic infection in our country, with a varied digestive symptomatology. We performed a prospective, transversal study, with the aim to establish the frequency of G. lamblia in digestive symptomatic patients submitted to upper gastrointestinal endoscopy examination trying to relate its isolation with the endoscopic findings. We studied 50 patients; they were submitted to upper endoscopy examination. During the procedure, we aspirated duodenal content and six duodenal biopsies were taken; 8 to 14 hours before endoscopy, they swallowed the Enterotest encapsulated string. The presence of G. lamblia was established by three methods (Enterotest, duodenal content, impront). The day, of the endoscopic examination they resolved a questionnaire of digestive symptoms they had during the last 4 weeks. The endoscopy was informed like normal in 15 patients. (30%). Duodenitis was detected by endoscopy in 9 patients (18%), but neither one of them demonstrated presence of G. lamblia. By the three diagnostic methods, the presence of G. lamblia was demonstrated in 5 patients (19%), without endoscopic duodenitis, being the digestive symptom scores not statistically significant respect to symptomatic patients without G. lamblia. We concluded that the three diagnostic methods used to identify G. lamblia were equally sensitive. No preponderance of digestive symptoms were present in patients with G. lamblia in relation to in our country patients without G. lamblia infection. We recommend to consider duodenal aspiration during endoscopy in order to discard giardiasis.

[Clinical evaluation of the use of proglumide in the treatment of the peptic ulcer semebrome]

The authors have made a clinical evaluation of Proglumida in 27 patients suffering from Peptic ulcer. Proglumida was administered orraly, 2 tables of 200 mg 3 times a day, 1.200 mg in 24 hours, during a period varying from 21 to 28 days. The painful symptoms improved in 96% of the pain occurred in 59% during the first 7 days of treatment. The dispeptic symptoms improved in all cases, disappearing completely in 74%, but in a slower fashion than the pain, and in 68% of the cases only from the second week of treatment onward. The objectivation of the pain by palpation of the epigastrium improved in all cases and did so in a significant form in 59% of the cases during the first seven days of treatment. No undesireable side effects have been observed in any of the cases. We believe that Proglumida is a pharmacological drug of positive action in the treatment of the ulcer syndrome, because of its favorable action and the absence of secondary side effects.