MeCP2-regulated miRNAs control early human neurogenesis through differential effects on ERK and AKT signaling.

Rett syndrome (RTT) is an X-linked, neurodevelopmental disorder caused primarily by mutations in the methyl-CpG-binding protein 2 (MECP2) gene, which encodes a multifunctional epigenetic regulator with known links to a wide spectrum of neuropsychiatric disorders. Although postnatal functions of MeCP2 have been thoroughly investigated, its role in prenatal brain development remains poorly understood. Given the well-established importance of microRNAs (miRNAs) in neurogenesis, we employed isogenic human RTT patient-derived induced pluripotent stem cell (iPSC) and MeCP2 short hairpin RNA knockdown approaches to identify novel MeCP2-regulated miRNAs enriched during early human neuronal development. Focusing on the most dysregulated miRNAs, we found miR-199 and miR-214 to be increased during early brain development and to differentially regulate extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase and protein kinase B (PKB/AKT) signaling. In parallel, we characterized the effects on human neurogenesis and neuronal differentiation brought about by MeCP2 deficiency using both monolayer and three-dimensional (cerebral organoid) patient-derived and MeCP2-deficient neuronal culture models. Inhibiting miR-199 or miR-214 expression in iPSC-derived neural progenitors deficient in MeCP2 restored AKT and ERK activation, respectively, and ameliorated the observed alterations in neuronal differentiation. Moreover, overexpression of miR-199 or miR-214 in the wild-type mouse embryonic brains was sufficient to disturb neurogenesis and neuronal migration in a similar manner to Mecp2 knockdown. Taken together, our data support a novel miRNA-mediated pathway downstream of MeCP2 that influences neurogenesis via interactions with central molecular hubs linked to autism spectrum disorders.

Disrupted in schizophrenia 1 (DISC1) L100P mutants have impaired activity-dependent plasticity in vivo and in vitro.

Major neuropsychiatric disorders are genetically complex but share overlapping etiology. Mice mutant for rare, highly penetrant risk variants can be useful in dissecting the molecular mechanisms involved. The gene disrupted in schizophrenia 1 (DISC1) has been associated with increased risk for neuropsychiatric conditions. Mice mutant for Disc1 display morphological, functional and behavioral deficits that are consistent with impairments observed across these disorders. Here we report that Disc1 L100P mutants are less able to reorganize cortical circuitry in response to stimulation in vivo. Molecular analysis reveals that the mutants have a reduced expression of PSD95 and pCREB in visual cortex and fail to adjust expression of such markers in response to altered stimulation. In vitro analysis shows that mutants have impaired functional reorganization of cortical neurons in response to selected forms of neuronal stimulation, but there is no altered basal expression of synaptic markers. These findings suggest that DISC1 has a critical role in the reorganization of cortical plasticity and that this phenotype becomes evident only under challenge, even at early postnatal stages. This result may represent an important etiological mechanism in the emergence of neuropsychiatric disorders.

Dysregulation of miR-34a links neuronal development to genetic risk factors for bipolar disorder.

Bipolar disorder (BD) is a heritable neuropsychiatric disorder with largely unknown pathogenesis. Given their prominent role in brain function and disease, we hypothesized that microRNAs (miRNAs) might be of importance for BD. Here we show that levels of miR-34a, which is predicted to target multiple genes implicated as genetic risk factors for BD, are increased in postmortem cerebellar tissue from BD patients, as well as in BD patient-derived neuronal cultures generated by reprogramming of human fibroblasts into induced neurons or into induced pluripotent stem cells (iPSCs) subsequently differentiated into neurons. Of the predicted miR-34a targets, we validated the BD risk genes ankyrin-3 (ANK3) and voltage-dependent L-type calcium channel subunit beta-3 (CACNB3) as direct miR-34a targets. Using human iPSC-derived neuronal progenitor cells, we further show that enhancement of miR-34a expression impairs neuronal differentiation, expression of synaptic proteins and neuronal morphology, whereas reducing endogenous miR-34a expression enhances dendritic elaboration. Taken together, we propose that miR-34a serves as a critical link between multiple etiological factors for BD and its pathogenesis through the regulation of a molecular network essential for neuronal development and synaptogenesis.

Treatment of Diastolic Heart Failure in Hypertensive Diabetic Patients : between Illusion and Achievements : Review

Hypertension is the most prevalent cardiovascular disease in the world. Because of associated morbidity and mortality; it is in one of the most important public health problems. Hypertension is the most important cause of heart failure with low or preserved ejection fraction. If hypertension develops concomitantly with diabetes mellitus; treatment of the two diseases becomes more complex. It is known that beta-blockers may induce type 2 diabetes; but new generation drugs such as nebivolol do not have this effect.There are many drugs with proven efficacy in lowering blood pressure; but the optimal treatment to prevent progression to heart failure is uncertain. Beta-blockers are a class of drugs with benefits for both hypertension and heart failure. Drugs in this class have different pharmacological properties in terms haemodynamic and cardiovascular effects. Nebivolol is a beta-blocker that causes vasodilatation mediated by nitric oxide release. This medicine lowers blood pressure; prevents endothelial dysfunction and improves coronary flow reserve and diastolic function independent of ventricular geometry changes. The action of nebivolol is superior to classic beta-blockers due to reversibility of subclinical changes in the left ventricle before the onset of heart failure.In the early stages of heart failure with preserved ejection fraction management is not yet established. Therefore it is important to know that in these situations nebivolol has beneficial effects

Arterial hypertension - prevalence of risk factors and morbide associations that increase cardiovascular risk.

Hypertension represents a serious problem in Romania, as there are over 3 million hypertensive people in our country. There is a high incidence of deaths caused by hypertension.WE PERFORMED AN ANALYTICAL PROSPECTIVE STUDY THAT AIMS TO DETERMINE: prevalence of arterial hypertension in a population from Cluj county, distribution on age and gender, arterial hypertension severity, association of hypertension with other cardiovascular risk factors. Our study included 2266 patients, age 14 years old up to over 90 years old, both masculine and feminine gender, known with hypertension and new-diagnosed ones. Each subject was submitted to an interview based on a questionnaire. Diagnosis of arterial hypertension was established according to ESH criteria that consider as hypertension: values over 140/90 mmHg. Out of all subjects submitted to the study 647 (29.74%) were diagnosed with arterial hypertension and, from these, 102 (15.13%) were new-diagnosed patients.We found out a predominance of arterial hypertension at the age of 51-60 and over 60, an increased involvement of feminine sex; an association of hypertension with other major cardiovascular risk factors: obesity, diabetes, dislypidemia.Arterial hypertension represents an important health problem in Romania due to an increased prevalence, major impact on morbidity and mortality by cardiovascular and cerebro-vascular disease. These facts accentuate the necessity of an early diagnosis, of making people aware of the severity of the disease and it's impact on their lifestyle.

Comparison of parasite lactate dehydrogenase based immunochromatographic antigen detection assay (optimal) with microscopy for detection of malaria parasites.

This study was done to compare the ability of a newly developed rapid malaria test OPtiMAL, an immunochromatographic antigen detection assay for the diagnosis of malaria using parasite lactate dehydrogenase, against standard microscopy. Blood samples were obtained from 232 patients suspected of having malaria. A total of 122 samples (52.5%) were positive by blood films while 118 (50.8%) were positive by OPtiMAL test. The blood film indicated that 21.4% (26 of 122) of the patients were positive for P. falciparum and 78.6% (96 of 122) were infected with P. vivax. OPtiMAL test showed that 21.2% (25 of 118) were positive for P. falciparum and 78.8% (93 of 118) were infected with P. vivax. This assay had sensitivities of 88.4% and 96.8% compared to traditional blood films for detection of P. falciparum and P. vivax malaria respectively. Thus OPtiMAL test can be used with or without traditional blood film examination for detection of both P. vivax and P. falciparum malaria and can be effectively used for the rapid diagnosis of malaria.

Intramedullary schistosomiasis.

A case study of intramedullary schistosomiasis in a 10-year-old child is reported. The patient presented with a short history of ascending paraparesis with no sensory loss. Sphincter dysfunction was rapid. She had surgical exploration and removal of a conus medullaris mass. Schistosomiasis was confirmed histologically. Combined steroid and praziquantel therapy improved her sphincter function and paraparesis.

[Combination of new electrophysiological and imaging techniques in the study of primary visual cortex function]. / Combinación de nuevas técnicas electrofisiológicas y de imagen en el estudio de la función de la corteza visual primaria.

INTRODUCTION: This work summarizes current research focused on explaining orientation selectivity of primary visual cortex (V1), and describes the electrophysiological and imaging techniques than are being used. DEVELOPMENT: The study of orientation selectivity in V1 is key to understanding the cortical mechanisms implicated in the processing of sensory information, but this enterprise has proved more challenging than previously thought and there is no consensus about the best model to explain V1 neurons activity. Ongoing research is focused on determining the importance of the different inputs that a cortical cell receives (thalamic and lateral cortical inputs), and their link to cortical architecture. To achieve that, current research is combining optical imaging techniques with intracellular recordings of V1 neurons. Recent findings have found differences in the synaptic integration performed by neurons located in the iso orientation domains vs orientation centers of the functional V1 map. CONCLUSIONS: Data describing synaptic activity combined with the cortical functional structure are yielding new clues about V1 computation, suggesting that there is more than one mechanism capable of generating orientation selectivity.

Combinación de nuevas técnicas electrofisiológicas y de imagen en el estudio de la función de la corteza visual primaria / Combination of new electrophysiological and imaging techniques in the study of primary visual cortex function

Objetivo.Se realiza una síntesis de las investigaciones que se llevan a cabo para tratar de explicar la selectividad a la orientación (SO) de la corteza visual primaria (V1), así como una descripción de las técnicas electrofisiológicas y de imagen que se utilizan. Desarrollo. El estudio de la SO de V1 es clave para comprender los mecanismos corticales de integración de la información, pero su desciframiento resulta complejo y, de momento, no hay consenso sobre cuál es el modelo que explica mejor la actividad de las neuronas de V1. Las investigaciones actuales se centran en averiguar el peso específico de las distintas entradas que puede recibir una célula cortical, tanto talámicas como procedentes de conexiones corticales laterales, y su relación con la arquitectura de la corteza. Para ello, se combinan técnicas de imagen óptica de señales intrínsecas con el registro intracelular de neuronas de V1. Experimentos recientes han demostrado diferencias entre la integración sináptica que realizan las neuronas localizadas en los dominios de isoorientación y las de los centros de orientación del mapa funcional de V1. Conclusiones. La información acerca de la actividad sináptica, combinada con la estructura funcional cortical, aporta nuevas pistas sobre la computación realizada por V1, las cuales sugieren que existe más de un mecanismo capaz de generar SO (AU)

Enhanced plasticity of retinothalamic projections in an ephrin-A2/A5 double mutant.

Ascending sensory information reaches primary sensory cortical areas via thalamic relay neurons that are organized into modality-specific compartments or nuclei. Although the sensory relay nuclei of the thalamus show consistent modality-specific segregation of afferents, we now show in a wild-type mouse strain that the visual pathway can be surgically "rewired" so as to induce permanent retinal innervation of auditory thalamic cell groups. Applying the same rewiring paradigm to a transgenic mouse lacking the EphA receptor family ligands ephrin-A2 and ephrin-A5 results in more extensive rewiring than in the wild-type strain. We also show for the first time that ephrin-A2 and ephrin-A5 define a distinct border between visual and auditory thalamus. In the absence of this ephrin-A2/A5 border and after rewiring surgery, retinal afferents are better able to invade and innervate the deafferented auditory thalamus. These data suggest that signals that induce retinal axons to innervate the denervated auditory thalamus may compete with barriers, such as the ephrins, that serve to contain them within the normal target. The present findings thus show that the targeting of retinothalamic projections can be surgically manipulated in the mouse and that such plasticity can be controlled by proteins known to regulate topographic mapping.

Disruption of retinogeniculate pattern formation by inhibition of soluble guanylyl cyclase.

During development of the visual system of the ferret, the terminals of retinal ganglion cell axons first segregate to form eye-specific layers and subsequently On-center and Off-center sublayers within the dorsal lateral geniculate nucleus (dLGN). Sublamination requires the activity of the afferent fibers, NMDA receptors, and nitric oxide synthase (NOS). We here report that soluble guanylyl cyclase (sGC), which in turn produces cGMP, is critically involved in the process of sublamination. cGMP expression is upregulated in both retinal terminals and postsynaptic dLGN cells during sublamination, and this expression is controlled by the activity of both NMDA receptors and NOS. Furthermore, the infusion of specific inhibitors of sGC or protein kinase G (PKG), a target of cGMP, prevents sublamination in vivo. We conclude that the sGC-cGMP-PKG pathway acts downstream of NMDA receptors and nitric oxide as an effector of the activity-dependent refinement of connections at this level of the mammalian visual system.

Foci of orientation plasticity in visual cortex.

Cortical areas are generally assumed to be uniform in their capacity for adaptive changes or plasticity. Here we demonstrate, however, that neurons in the cat striate cortex (V1) show pronounced adaptation-induced short-term plasticity of orientation tuning primarily at specific foci. V1 neurons are clustered according to their orientation preference in iso-orientation domains that converge at singularities or pinwheel centres. Although neurons in pinwheel centres have similar orientation tuning and responses to those in iso-orientation domains, we find that they differ markedly in their capacity for adaptive changes. Adaptation with an oriented drifting grating stimulus alters responses of neurons located at and near pinwheel centres to a broad range of orientations, causing repulsive shifts in orientation preference and changes in response magnitude. In contrast, neurons located in iso-orientation domains show minimal changes in their tuning properties after adaptation. The anisotropy of adaptation-induced orientation plasticity is probably mediated by inhomogeneities in local intracortical interactions that are overlaid on the map of orientation preference in V1.

Development and plasticity of cortical areas and networks.

The development of cortical layers, areas and networks is mediated by a combination of factors that are present in the cortex and are influenced by thalamic input. Electrical activity of thalamocortical afferents has a progressive role in shaping cortex. For early thalamic innervation and patterning, the presence of activity might be sufficient; for features that develop later, such as intracortical networks that mediate emergent responses of cortex, the spatiotemporal pattern of activity often has an instructive role. Experiments that route projections from the retina to the auditory pathway alter the pattern of activity in auditory thalamocortical afferents at a very early stage and reveal the progressive influence of activity on cortical development. Thus, cortical features such as layers and thalamocortical innervation are unaffected, whereas features that develop later, such as intracortical connections, are affected significantly. Surprisingly, the behavioural role of 'rewired' cortex is also influenced profoundly, indicating the importance of patterned activity for this key aspect of cortical function.

Investigation of human papillomavirus in transitional cell carcinomas of the urinary bladder in South Africa.

AIM: To investigate the prevalence of human papillomavirus in transitional cell carcinoma of the urinary bladder in South Africa. METHODS: Ninety-one archival samples of bladder transitional cell carcinoma were subjected to polymerase chain reaction (PCR) and non-isotopic in situ hybridisation (NISH) for the detection of human papillomavirus 6, 11, 16, 18, 31, and 33 genotypes. RESULTS: HPV was detected in only one case with PCR. HPV was not detected in any of the cases subjected to the NISH system. CONCLUSION: This study shows that although HPV has been shown to be associated with uterine cervical and esophageal squamous cell carcinomas in South Africa, this virus is not present in the transitional cell carcinoma of the urinary bladder in this geographical location. It is suggested that other factors, including nitrosamine exposure, p53 mutation, and additional unknown chromosomal events, may play a role in the carcinogenesis of this neoplasm in the bladder.

Specific roles of NMDA and AMPA receptors in direction-selective and spatial phase-selective responses in visual cortex.

Cells in the superficial layers of primary visual cortex (area 17) are distinguished by feedforward input from thalamic-recipient layers and by massive recurrent excitatory connections between neighboring cells. The connections use glutamate as transmitter, and the postsynaptic cells contain both NMDA and AMPA receptors. The possible role of these receptor types in generating emergent responses of neurons in the superficial cortical layers is unknown. Here, we show that NMDA and AMPA receptors are both involved in the generation of direction-selective responses in layer 2/3 cells of area 17 in cats. NMDA receptors contribute prominently to responses in the preferred direction, and their contribution to responses in the nonpreferred direction is reduced significantly by GABAergic inhibition. AMPA receptors decrease spatial phase-selective simple cell responses and generate phase-invariant complex cell responses.