No description available.

Background: Children exposed to pesticides are susceptible for neurodevelopmental disruption. Data from developing countries are scarce. Aim: Assessing long-term and recent pesticide exposure in Nicaraguan children in relation to parental pesticide use and examining potential associated neurobehavioral effects. Methods: In the first study, pre- and post-spraying urinary residues of the chlorpyrifos metabolite TCPY and diazinon metabolite IMPY were measured among 7 subsistence farmers and 10 plantation workers, and in one child per worker. In the second study, for 110 children in an agricultural village and 22 in a non-agricultural village, aged 7-9, parental pesticide use was assessed by hours of spraying and kilograms of active ingredients during pre-and-postnatal time windows, as proxies for children’s long term pesticide exposures. Urinary TCPY, 3-PBA (pyrethroid metabolite), and 2,4-D were determined in 211 samples of 74 children of the agricultural village. IQ components and total IQ (WISC-IV) were evaluated in all agricultural village children. Behavior was evaluated with the Conners’ Teacher Rating Scale-Revised: Short. Multivariate linear regression models assessed associations between long-term and recent exposure to organophosphates and pyrethroids and cognitive and behavioral scales. Results: In study 1, post-spraying urinary levels of pesticide metabolites of subsistence farmers and their children were highly correlated (r=0.85), but not those of plantation workers and their children. In study 2, a wide range of exposures was reported by parents for all pesticides and time windows. The median urinary TCPY (3.7 μg/g creatinine), 3-PBA (2.8), and 2,4-D (0.9) were comparable to other studies for TCPY and 3-PBA but high for 2,4-D. Maximum levels were the highest reported for all compounds. Prenatal use of organophosphates affected working memory, and methamidophos also verbal comprehension and total IQ. Urinary TCPY was associated with poorer working memory. Organophosphate exposures were not associated with children’s behavior. Pyrethroid exposure during the first year of life associated with poorer perceptual reasoning and behavior, and urinary 3-PBA with a number of cognitive functions and ADHD in girls but not in boys. Conclusion: Nicaraguan children in poor agricultural areas are highly exposed to pesticides, which is influenced by parental pesticide use in subsistence farms. Organophosphate and pyrethroid exposures adversely affect their neurobehavioral development.

One feature of the brain is that different parts of it respond to different stimuli. This means not all brain regions or neurons within those regions are active at a given moment. This feature of the brain gives it the ability to encode and store a wide range of stimuli that are then used to make predictions about a changing external environment. Activation of non-overlapping neural populations is fundamental to the ability to encode a wide range of stimuli to represent a changing environment. To examine the limits of this idea we used genetic tools to label active cell populations following a neutral stimulus presentation or a learned negative association with the same stimulus. The study examined the degree of similarity between these active populations by comparing key features of the active neurons including gene expression and monosynaptic inputs. Another feature of the brain is its ability to store information. In a neural population recently activated by a salient stimulus, molecular processes occur that result in the formation and maintenance of a memory. Collectively these processes are referred to as plasticity, and act on short and long time scales to strengthen the connections between active neurons and weaken the connections between inactive ones. Plasticity processes are not only necessary for the formation and storage of memories but also for wiring up the nervous system during development. A molecule called ZIP has been shown to erase memories months after formation and specifically affects plasticity on longer time scales. However, the effects of ZIP on the developing brain are not well understood and difficult to study using ZIP’s typical delivery method of injection into the brain. To facilitate a developmental study of ZIP’s effects, we made a genetic tool that can specify where and when ZIP is delivered to the brain. Results of the study indicated that males were particularly vulnerable to ZIP during early development while females were unaffected. Together these results provide insight into the limits of information coding potential at the anatomical level and reveal a fundamental difference in plasticity processes in males and females. / 10000-01-01

Submitted by Caio Sergio Galina Spilla (caiospilla@hotmail.com) on 2018-06-13T12:51:18Z No. of bitstreams: 1 Dissertação - Mestrado, SPILLA, C. S. G..pdf: 2498178 bytes, checksum: f7d9be339f1c3e5b2aacdf4025b377c3 (MD5) / Approved for entry into archive by Satie Tagara (satie@marilia.unesp.br) on 2018-06-13T15:34:17Z (GMT) No. of bitstreams: 1 spilla_csg_me_mar.pdf: 2498178 bytes, checksum: f7d9be339f1c3e5b2aacdf4025b377c3 (MD5) / Made available in DSpace on 2018-06-13T15:34:17Z (GMT). No. of bitstreams: 1 spilla_csg_me_mar.pdf: 2498178 bytes, checksum: f7d9be339f1c3e5b2aacdf4025b377c3 (MD5) Previous issue date: 2018-05-25 / Não recebi financiamento / Reações imunes geradas no organismo materno durante o período gestacional podem provocar alterações no desenvolvimento do feto. O LPS, endotoxina lipopolissacarídea presente na parede das bactérias gram-negativas, é capaz de gerar a produção de citocinas, mimetizando dessa forma um quadro de inflamação pré-natal quando administrado na fêmea prenhe durante o período gestacional. A prole de ratas prenhes expostas a esta endotoxina pode apresentar assim diversos problemas comportamentais e/ou cognitivos que refletem alterações ocorridas no sistema nervoso central (SNC) durante o seu desenvolvimento. Entre as diversas patologias que podem resultar de um transtorno no neurodesenvolvimento está o transtorno do espectro autista (TEA). Ainda sem uma causa definida em humanos, estima-se que cerca de uma a cada 150 crianças nascidas atualmente são acometidas por essa patologia. Distúrbios de comportamento e de comunicação/interação social constituem a díade que caracteriza o TEA e dependendo do grau de acometimento é comum encontrar também nestes e de forma geral em indivíduos com transtornos de neurodesenvolvimento problemas atencionais, de aprendizado e memória. O quadro inflamatório no período de gestação causa uma série de alterações no organismo materno, sendo que algumas destas alterações alcançam o feto em desenvolvimento. Uma destas alterações pode ser a redução no conteúdo de melatonina na circulação materna e fetal. A melatonina, hormônio produzido pela glândula pineal, apresenta funções sincronizadora, antioxidante e neuroprotetora que podem ser importantes durante o neurodesenvolvimento e a alteração na síntese e liberação desse hormônio no organismo materno ao longo da gestação vem sendo correlacionada a casos de TEA. Além disso, a exposição ao LPS durante o desenvolvimento do SNC em um modelo animal resulta em uma prole que apresenta comportamentos autísticos. Apesar destes dados, os efeitos desse quadro pré-natal no comportamento, na morfologia e na neuroquímica de áreas encefálicas da prole ainda não foram totalmente esclarecidos e sua elucidação pode contribuir como base de conhecimento para estudos que investiguem prevenção e terapias farmacológicas ou comportamentais nessas patologias. O presente trabalho teve como objetivos verificar se o quadro inflamatório pré-natal induzido por LPS: 1) Altera a concentração plasmática de melatonina materna, 2) altera a expressão de comportamentos que dependem da função de memória espacial e 3) induz mudanças morfométricas e neuroquímicas no hipocampo. Para atingir o primeiro objetivo foi coletado o sangue de ratas prenhe 3 h (fase de claro) e 16 h (fase de escuro) após à exposição ao LPS ou a solução salina e a dosagem de melatonina foi realizada por meio do método ELISA. Para alcançarmos o segundo e terceiro objetivos as proles de ratas expostas ao LPS e de ratas controles expostas a solução salina no dia gestacional 9,5 foram avaliadas por meio de teste comportamental de alternância espontânea no labirinto em T. Em seguida, os animais foram perfundidos e os encéfalos processados para o estudo do volume hipocampal por estereologia, para análise de expressão neuronal das proteínas ligantes de cálcio calretinina e parvalbumina e para análise de expressão glial da proteína glial fibrilar ácida (GFAP) e da proteína de associação de ligação ao cálcio ionizada – 1 (IBA-1) por meio da técnica de imunohistoquímica. Os resultados mostraram que houve queda no conteúdo plasmático de melatonina noturno e aumento no conteúdo diurno após injeção com LPS nas fêmeas prenhes. A prole do grupo controle apresentou melhor desempenho no teste comportamental quando comparado a prole do grupo LPS. O hipocampo da prole do grupo LPS não apresentou diferença de volume total do desta estrutura em comparação ao grupo controle. Também não houve alteração na expressão de GFAP em astrócitos hipocampais no grupo LPS em relação ao controle. Por outro lado, ocorreu aumento na expressão de IBA-1, marcador de microglia, nas regiões do CA1, CA2 e CA3 no hipocampo da prole do grupo LPS em relação a prole do grupo controle. A prole do grupo LPS, considerada um modelo animal de autismo também apresentou variações na expressão das proteínas ligantes de Cálcio no hipocampo com menor expressão da proteína parvalbumina e maior expressão da proteína calretinina que o grupo controle. Os resultados mostraram que a exposição materna ao LPS foi capaz de alterar a concentração de melatonina plasmática circulante e que a prole exposta a esse ambiente inflamatório pré-natal apresentou alterações de comportamento dependente da memória espacial. Além disso, os resultados nos permitem concluir que tais alterações na memória espacial não são coincidentes com alterações no volume do hipocampo ou na reatividade astrocitária, mas sim com a ativação microglial e com alterações na neuroquímica dos neurônios gabaérgicos hipocampais que expressam as proteínas ligantes de cálcio e que conhecidamente controlam as conexões excitatórias e inibitórias envolvidas nos fenômenos de memória. / Immune reactions generated in the maternal organism during the gestational period may cause changes in the fetal development. The endotoxin lipopolysaccharide (LPS) present on the wall of Gram-negative bacteria is able to induce the production of cytokines, mimicking a state of prenatal inflammation when administered in the pregnant female during the gestational period. The offspring of pregnant rats exposed to this endotoxin may present several behavioral and/or cognitive problems that reflect changes in the central nervous system (CNS). The autism spectrum disorder (ASD) is one of this neurodevelopmental conditions, and although without a definite cause in humans, is related to be present in one to every 150 children born. Behavior and communication/social interaction disorders constitute the dyad that characterizes the ASD. Besides these, depending on the degree of involvement it is common to find in these individuals‟ attention, learning and memory problems. Melatonin, a hormone produced by the pineal gland, presents several functions during neurodevelopment and the alteration in the synthesis and release of this hormone in the maternal organism throughout pregnancy has been correlated to cases of ASD. Investigations about the effects of a prenatal inflammatory condition in behavior, in the morphology and neurochemistry of brain areas can contribute for future pharmacological or behavioral studies in these patients. Considering that exposure to LPS during the development of CNS in an animal model results in offspring presenting autistic behaviors, the present work aimed to check whether the prenatal inflammatory condition: 1) Changes the maternal melatonin plasma concentration, 2) alters behaviors that depend on the spatial memory function and 3) induces morphometric and neurochemical changes in the hippocampus. For this, blood from pregnant rats 03h and 16h after LPS exposure was collected and the melatonin dosage was performed using the ELISA method. Offsprings of rats exposed to the LPS (autism model) or saline (control) on the 9.5 gestational day were evaluated in the T-maze spontaneous alternation test. After, the animals were perfused with 4% paraformaldehyde and the brains were processed for the hippocampal volume quantification and for the analysis of the calretinin, parvalbumin, glial fibrillary acidprotein (GFAP) and ionized calcium binding association protein – 1 (IBA-1) expression by immunohistochemistry. There was difference in the plasma melatonin dosage in the day and night periods of the pregnant females of the control group and the LPS group. The results showed that the control group presented better performance in behavioral testing when compared to the autism model. The hippocampal volume showed no difference between the groups, as well as the expression of the GFAP in astrocytes. There was an increase in IBA-1 expression in all regions of the hippocampus except in the dentate gyrus in the autism model group in relation to the control group.The autism model presented lower expression of the parvalbumin and greater expression of de calretinin than the control group. The results showed that maternal exposure to LPS was able to alter maternal plasma melatonin concentration and that the offspring exposed to prenatal inflammatory environment showed deficits in behaviors dependent of spatial memory and indicate that these behaviors deficits are not coincident with changes in the hippocampal volume or in astrocytic reactivity, but but with microglial activation and with changes in the calcium binding proteins expression in gabaergic neurons of the hippocampus which are known to control excitatory and inhibitory sinapses involved in the memory phenomena.

La voie biosynthétique du mevalonate (MVA) est indispensable à la production de molécules qui sont essentielles dans grand nombre de processus physiologiques mais la plupart des études effectuées sur le rôle physiologique de cet important processus métabolique dans le système nerveux central restent simplement en corrélation. Pour autant, le but des études présentées dans cette thèse a été: évaluer les protéines de la voie du MVA dans différentes régions du cerveaux de rat en prenant en considération l’éventuelle modulation selon le sexe et l’âge; analyser l’impact de la voie sur le développement des neurones set sur le comportement des rats; explorer l’impact de la voie dans une pathologie du neurodéveloppement comme l’autisme. Les résultats démontrent que la voie biosynthétique du MVA est régulée différemment selon la région du cerveau analysée, en fonction de l’âge et du sexe. La voie biosynthétique du MVA revêt un rôle critique dans la modulation physiologique du comportement animal et du développement des neurones Pour finir, mes données démontrent, dans un modèle expérimental d’autisme, que la voie biosynthétique du MVA est modulée dans plusieurs région du SNC selon l’âge. / The mevalonate (MVA) pathway is an essential metabolic pathway that leads to the production of molecules important in several physiological processes and play pivotal roles in the brain. An imbalance of this pathway in CNS is accompanied by the onset of several neuropathological descriptions. Despite these observations, the physiological importance of this metabolic process in the brain has remained unclear. My aim was to study the presence and the regulation of the proteins involved in the MVA pathway in different rat brain areas in a sex- and age-dependent manner, to analyze the impact of the key enzymes on neuronal development and on rat behavior, and to explore whether the MVA pathway is affected in a neurodevelopmental disease such as autism. My results demonstrate that this metabolic process is expressed and modulated in a highly region-dependent manner and that age and sex induce physiological differences. Notably, it impact on behavior and neuronal development suggesting that this pathway may be considered as potential molecular target when designing novel therapeutic approaches for the treatment of these pathologies.

<p>Polybrominated diphenyl ether (PBDE) flame retardants are ubiquitous contaminants in the environment due to their heavy usage in plastics, foam, and textiles to comply with flammability standards from the 1970s through the late 2000s. Due to their toxicity and persistence in the environment, two of the three PBDE commercial mixtures (PentaBDE and OctaBDE) were banned by the Stockholm Convention on Persistent Organic Pollutants in 2009. The DecaBDE commercial mixture, which consists primarily of the fully brominated congener BDE-209, has been banned or phased out in the United States and Europe but is still in use in other parts of the world. Human exposure to PBDEs persists via environmental reservoirs of PBDEs and products produced before the bans/phase-outs. PBDEs disrupt thyroid hormone levels and neurodevelopment in fish and rodents and are associated with altered thyroid hormone levels and neurodevelopmental impairments in humans. However, the mechanism by which PBDEs alter neurodevelopment remains unclear. Knowledge of the mechanisms and molecular targets of PBDEs is necessary for a causal link to be established between PBDEs and neurodevelopmental impairments. The hypothesis of this thesis research is that PBDEs alter thyroid hormone levels in the brain by interfering with the activity of PBDE-metabolizing deiodinase enzymes in brain cells, which may result in decreased levels of thyroid hormones in the brain and impaired neurodevelopment. </p><p>In the first aim of this thesis research, the biotransformation of PBDEs was examined to determine whether hydroxylated PBDEs (OH-BDEs) are formed in the human brain. In biotransformation assays performed with human astrocytes, which are cells located at the blood brain barrier, no debrominated or OH-BDE metabolites were identified. The results indicate that the enzyme responsible for PBDE hydroxylation (CYP2B6) was not expressed in sufficient quantities to metabolize PBDEs in the astrocyte cells used in this study, but future studies should analyze the potential for PBDE hydroxylation in other brain cells. </p><p>In the second aim of this thesis research, the effects of PBDEs on the thyroid-activating enzyme Type 2 deiodinase (DIO2) were determined in human astrocyte cells. DIO2 converts thyroxine (T4) into triiodothyronine (T3), which is the primary ligand that binds to the thyroid nuclear receptors, and is a very important signaling molecule during neurodevelopment. Cultured primary astrocytes and a human glioma cell line (H4 cells) were exposed to PBDEs and OH-BDEs, and changes in DIO2 activity were measured using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Exposure to BDE-99, -153, and -209, 3-OH-BDE-47, and 5'-OH-BDE-99 all resulted in significant decreases in DIO2 activity in the H4 cells by up to 80% at doses of 500-1,000 nM. Further experiments deduced that the primary mechanism responsible for this decrease in activity was attributed to decreased DIO2 mRNA expression, increased post-translational degradation of DIO2, and competitive inhibition of DIO2. The reduction in DIO2 activity by PBDE and OH-BDE exposures could potentially reduce the concentration of T3 in the brain, which may be responsible for the neurodevelopmental impairments produced by exposure to this class of compounds and needs to be further explored. </p><p>In the third aim of this thesis research, the effects of PBDEs and OH-BDEs were examined in the H4 cells and in a mixed culture containing a human neuroblastoma cell line (SK-N-AS cells). The SK-N-AS cells express the thyroid hormone-inactivating enzyme Type 3 deiodinase (DIO3), which works in concert with DIO2 to buffer the concentration of T3 in the brain. Exposure to BDE-99 decreased the concentration of T3 and the inactive thyroid hormone rT3 in the cell culture medium of co-cultured cells by 59-76%. 3-OH-BDE-47 competitively inhibited DIO3 with an IC50 of 19 uM. 5'-OH-BDE-99 increased the rT3 concentrations in cell culture medium by 400%, increased DIO3 activity in exposed cells by 50%, and increased DIO3 catalytic activity in cellular homogenates by over 500%. Further effects on the mRNA expression of several thyroid-regulated genes (DIO3, TR-a, TR-b, MCT8, and ENPP2) and oxidative respiration were also assessed in the SK-N-AS cells. DIO3 mRNA expression increased by 9 fold in cells exposed to 400 nM BDE-99, and ENPP2 mRNA expression increased by 2 fold in cells exposed to 500 nM BDE-99 and a mixture of the three congeners, but no other significant effects on mRNA expression were observed. The basal respiration rates and other parameters of oxidative respiration were also not significantly altered by exposure to PBDEs or OH-BDEs, but proton leak was increased by over 400% in cells exposed to 2 uM 5'-OH-BDE-99. </p><p>This was the first study to examine the effects of an environmental contaminant on human DIO2 and DIO3 in cultured cells. The results indicated that BDE-99 and OH-BDEs decreased the activity of DIO2 and 5'-OH-BDE-99 increased the activity of DIO3, which combined would lead to decreased levels of T3 exported from the cells into the extracellular environment. These results provide more evidence that disruption of DIO2 and DIO3 by PBDEs during development may mediate the neurodevelopment effects associated with PBDEs.</p> / Dissertation

No description available.

The human brain, as much as it is “unaccountable” in the eyes of Virginia Woolf, is a marvel. It is the evolutionary increase in brain size, especially in the cerebral cortex, that both allowed Mrs Woolf to create and us to perceive the beautiful imagery that exists in her fictional world. The evolutionary increase in brain size in part reflects the increase in the number of neurons generated during neocortical development. This in turn reflects two principal features of cortical expansion, namely, an increase in the number of neural stem and progenitor cells (from here on referred to as progenitor cells) and their neurogenic potential. Strikingly, in order to cater for this increase in progenitor cells and neurogenic potential, there is a significant expansion and diversification of basal progenitors in the subventricular zone (SVZ). Basal progenitors can be divided into three types: basal intermediate progenitors (bIPs), basal radial glias (bRGs) and transit-amplifying progenitors (TAPs). bIPs are the most abundant progenitors in the mouse SVZ. These cells are non-polar and are Pax6 and Sox2 negative, but Tbr2 positive. They have limited proliferative capacity as they can divide only once to produce two neurons. bRGs and TAPs, on the other hand, are able to undergo multiple rounds of division and exist in higher abundance in gyrencephalic brains (for bRG, in humans up to 50% versus mouse 5% at mid-neurogenesis). The morphology of bRGs are reported to be dynamic (fluctuating between states of having process(es) to none), whereas TAPs are generally described to be non-polar during mitosis. bRGs are known to express Pax6 and Sox2 but not Tbr2 while TAPs are known to express both Pax6 and Tbr2. The increase in the proportion of these self-renewing basal progenitors (more specifically bRGs) might allow for cortical expansion. Hence, the main objective of this doctoral work was to generate more bRGs in the mouse dorsal telencephalon, the region that ultimately develops to become the cerebral cortex. To achieve this objective, two approaches were used– (i) a general approach by microinjecting a pool of ferret poly-A+ RNA and (ii) a candidate approach by conditionally expressing the transcription factor Pax6. In the general approach, the microinjection technique was first established and validated in an organotypic slice culture of the mouse dorsal telencephalon. A pool of ferret poly-A¬+ RNA extracted at P1, the developmental stage corresponding to the peak of bRG production, was then microinjected into the dorsal telencephalon. We hypothesized that at the peak of bRG production, the “instructive” messages on how to generate bRG would be at their peak. Hence, by introducing these “instructive” messages into a apical radial glia (aRG), these cells would thus “know” how to generate bRGs. At 24 h after microinjection, only aRGs, the predominant progenitor residing in the ventricular zone during mid-neurogenesis were recovered. At 48 h after microinjection, however, 75% of cells that translated the ferret poly-A¬+ RNA had a morphology reminiscent of bRG. These cells were located away from the ventricular surface and had a basal but not apical process. We conclude from these experiments that we did indeed generate bRG-like cells in the mouse dorsal telencephalon via microinjection of the ferret poly-A¬+ RNA. In the candidate approach, this work aimed to conditionally express Pax6, a transcription factor that has been linked to proliferation and neurogenesis in aRG. More specifically, as there is a significant increase in the number of Pax6 positive cells (bRGs) in the SVZ of gyrencephalic animals during mid-neurogenesis, we wanted to recapitulate this phenomenon in the mouse dorsal telencephalon, where Pax6 is normally downregulated. To achieve this, the Tis21–CreERT2 mouse was used. Tis21 is a pan-neurogenic marker that is switched on once aRG switches from a proliferative division (i.e. 1 aRG⇒2aRG) to a neurogenic division (i.e. 1aRG⇒1aRG+1bIP). Consequently, the neurogenic aRGs and its progeny, bIPs would thus be Tis21 positive. By conditionally expressing Pax6 in Tis21 positive aRGs, the ectopic expression of Pax6 was successfully induced in the SVZ of the mouse dorsal telencephalon. Interestingly, conditional expression of Pax6 increased the percentage of proliferating cells in the SVZ. However, instead of producing more bIPs as predicted by the neurogenic division of Tis21 positive aRGs, these cells had the cell morphology, transcription factor expression profile, and division-type of bRGs and/or TAPs. Thus, using the conditional expression of Pax6 we were able to generate more bRG-like progenitors in the mouse dorsal telencephalon. The fate of these conditionally expressing Pax6 progenitors at a later stage was then investigated. A phenotypic change in the behaviour of neurons generated was observed. Instead of migrating into the cortical plate, cells that were highly expressing Pax6 formed a heterotopia at the SVZ or intermediate zone, suggestive of Pax6 interfering with neuronal migration. Interestingly, of those lowly expressing Pax6 cells that successfully migrated to the CP, a disproportionate majority became upper layer neurons. As the fate of neurons are dependent on their date of birth (i.e early born neurons are normally found in the deep layer while late born neurons are normally found in the upper layer), the increase in the upper layer neurons is consistent with the fact that conditionally expressing Pax6 delayed the birth of these neurons by delaying neurogenesis in order to increase the number of proliferative divisions. Interestingly, this increase in upper layer neurons is consistent with the difference between small- and large-brained species. In conclusion, through this work more bRGs was successfully generated in the mouse dorsal telencephalon through two distinct but complementary approaches.

Synaptogenesis is a critical process in the establishment of neuronal connectivity during brain development. The key step is to transduce external stimuli into the internal signaling cascades. Cell adhesion molecules and scaffold proteins facilitate the transduction to achieve optimal connectivity through PDZ domain mediated interaction. FRMPD2, a product of a human-specific multi-copy gene with three PDZ domains, has been shown to localize to the tight junctions in epithelial cells, suggesting a role in inter-cellular interaction. Although the correlation between neurodevelopmental disorders and gene dosage alteration of FRMPD2 has been observed, its role in the nervous system remains unknown. Therefore, I investigated the role of FRMPD2 in neurodevelopment. I found that FRMPD2 localizes at the excitatory synapses and promotes synaptogenesis in rat neurons. Mechanistically, FERM domain is required for synaptic localization of FRMPD2 through the interaction with F-actin in spines. More importantly, I found that FRMPD2 associates with cell adhesion molecule Neuroligin-1 through PDZ domain mediated interaction, resulting in an increase in Neuroligin-1 surface expression and up-regulation of synaptogenesis. Results from in utero electroporation showed that overexpression of FRMPD2 in mouse brains delayed neuronal migration and increased dendritic arborization and spine formation. Remarkably, viral overexpression of FRMPD2 in mouse brains improved memory retention. Abnormalities in synaptogenesis during neurodevelopment can cause neurodevelopmental disorders, such as Autism Spectrum Disorders (ASDs). Genomic studies from cohorts of ASD patients have revealed the prevalence of dysfunctional genes in the ubiquitin-proteasome pathway, especially the E3 ligases, suggesting the E3 ligase as a key component in ASD pathogenesis. Genomic duplication or deletion of PARK2 gene, a E3 ligase gene, has been identified in ASD patients. Therefore, I explored the autistic phenotypes of the Park2 knockout (KO) mice. Indeed, the KO mice demonstrated features of typical ASD behaviors. Further, Park2 KO mice showed a reduction in spine number, dendritic arborization, and levels of neuronal activity. The alterations in synaptic property in Park2 KO mice may serve as the etiological factor for ASD. These findings provide insights into the role of a novel synaptic organizer scaffold protein for synapse formation during brain development, and a novel ASD model. / 2020-11-12T00:00:00Z

No description available.