Expression pattern of the CELF1 protein in the frontal lobe during human fetal brain development

Razvoj mozga čovjeka je složen proces koji započinje tijekom ranog embrionalnog razdoblja. Moždana kora fetusa građena je od privremenih fetalnih zona koje ne postoje u moždanoj kori odraslog čovjeka. Proučavajući moždano tkivo, od ventrikularne površine (uz moždane komore) prema pijalnoj površini mogu se razaznati ventrikularna zona, subventrikularna zona, intermedijalna zona, subplate zona, kortikalna ploča i marginalna zona. Ventrikularna i subventrikularna zona jesu proliferativne zone u kojima se rađaju novi neuroni, a zatim slijedi proces radijalne migracije kroz intermedijalnu zonu, koji potpomaže radijalna glija, vrsta fetalnih astrocita. Između 12. i 15. tjedna gestacije javlja se subplate zona kao jedna od ključnih privremenih fetalnih zona za razvoj moždane kore. Subplate zona ima niz razvojnih funkcija, između ostalog, služi kao čekaonica za talamokortikalne aksone koji urastaju u kortikalnu ploču, te je mjesto intenzivne rane sinaptogeneze. U 8. tjednu embrionalnog razvoja nastaje kortikalna ploča koja obilježava prijelaz iz embrionalnog u fetalno razdoblje. Najpovršniji sloj fetalne moždane kore naziva se marginalna zona. Subplate, kortikalna ploča i marginalna zona zajedno čine razvojnu osnovu kore velikog mozga. Poznata je uloga RNA-vezujućeg proteina iz CELF obitelji, CELF1, tijekom normalnog razvoja mozga te u patogenezi miotonične distrofije. CELF1 ima niz uloga u metabolizmu RNA molekule, poput translacije, prekrajanja i regulacije stabilnosti RNA molekule. Nedavno je pokazano da je Celf1 regulator razvoja glutamatergičkih neurona putem translacijske represije Elavl4. Unatoč tome, ekspresijski obrazac CELF1 u moždanoj kori čovjeka nije poznat. Cilj diplomskog rada bio je istražiti obrazac ekspresije CELF1 u moždanoj kori čeonog režnja čovjeka tijekom srednje fetalnog razdoblja, od 12.5 do 21. tjedna nakon začeća (TNZ). Metodom po Nisslu vizualizirali smo granice privremenih fetalnih zona, dok smo imunohistokemijskom i imunofluorescencijskom metodom vizualizirali CELF1, te pratili obrazac njegove ekspresije u moždanoj kori čeonog režnja čovjeka. Rezultati su pokazali kako je tijekom srednjeg fetalnog razdoblja CELF1 intenzivno eksprimiran u proliferativnim zonama moždane kore, te u kortikalnoj ploči odnosno subplate zoni.Human brain development is a very complex process that begins during the early embryonic period. The fetal cerebral cortex is composed of the transient fetal compartments which do not exist in an adult brain. From the ventricular to the pial surface of the cerebral wall, there is the ventricular zone, subventricular zone, intermediate zone, subplate zone, cortical plate and close to the pial surface - marginal zone. Ventricular and subventricular zone are proliferative compartments where neurons are born and then migrate to their final destination through the intermediate zone. Radial glia, type of fetal astrocytes, help newly born neurons in the process of migration. The subplate zone is formed between the 12th and 15th postconceptional weeks (PCW), as one of the crucial compartments in cortical development. Subplate zone is a „waiting“ compartment for thalamocortical axons that are waiting to grow in the cortical plate and the site of intensive early synaptogenesis. In the 8th gestational week, the cortical plate is formed, which marks the transition from embryonic to fetal period. Cortical plate and subplate zone, together with the most superficial layer, so called the marginal zone, form the neocortical anlage. The aim of the study was to reveal the expression pattern of the RNA binding protein from the CELF family, called CELF1, during midfetal period. CELF1 plays an important role in RNA metabolism, such as translation, splicing, and regulation of the stability of the RNA molecule. Furthermore, CELF1 is involved in glutamatergic neuron identity during normal cortical development and in the pathogenesis of myotonic dystrophy. However, CELF1 expression pattern in human cerebral cortex is still unknown. In order to visualize the CELF1 expression pattern in the transient fetal cortical zones throughout midfetal period we used immunohistochemistry, immunofluorescence and histological Nissl staining as a cytoarchitectonic marker to delineate transient cortical compartments. Our results showed that during midfetal cortical development, CELF1 expression is enriched in the proliferative zone, followed by expression in the cortical plate and subplate zone

Expression pattern of the CELF1 protein in the frontal lobe during human fetal brain development

Razvoj mozga čovjeka je složen proces koji započinje tijekom ranog embrionalnog razdoblja. Moždana kora fetusa građena je od privremenih fetalnih zona koje ne postoje u moždanoj kori odraslog čovjeka. Proučavajući moždano tkivo, od ventrikularne površine (uz moždane komore) prema pijalnoj površini mogu se razaznati ventrikularna zona, subventrikularna zona, intermedijalna zona, subplate zona, kortikalna ploča i marginalna zona. Ventrikularna i subventrikularna zona jesu proliferativne zone u kojima se rađaju novi neuroni, a zatim slijedi proces radijalne migracije kroz intermedijalnu zonu, koji potpomaže radijalna glija, vrsta fetalnih astrocita. Između 12. i 15. tjedna gestacije javlja se subplate zona kao jedna od ključnih privremenih fetalnih zona za razvoj moždane kore. Subplate zona ima niz razvojnih funkcija, između ostalog, služi kao čekaonica za talamokortikalne aksone koji urastaju u kortikalnu ploču, te je mjesto intenzivne rane sinaptogeneze. U 8. tjednu embrionalnog razvoja nastaje kortikalna ploča koja obilježava prijelaz iz embrionalnog u fetalno razdoblje. Najpovršniji sloj fetalne moždane kore naziva se marginalna zona. Subplate, kortikalna ploča i marginalna zona zajedno čine razvojnu osnovu kore velikog mozga. Poznata je uloga RNA-vezujućeg proteina iz CELF obitelji, CELF1, tijekom normalnog razvoja mozga te u patogenezi miotonične distrofije. CELF1 ima niz uloga u metabolizmu RNA molekule, poput translacije, prekrajanja i regulacije stabilnosti RNA molekule. Nedavno je pokazano da je Celf1 regulator razvoja glutamatergičkih neurona putem translacijske represije Elavl4. Unatoč tome, ekspresijski obrazac CELF1 u moždanoj kori čovjeka nije poznat. Cilj diplomskog rada bio je istražiti obrazac ekspresije CELF1 u moždanoj kori čeonog režnja čovjeka tijekom srednje fetalnog razdoblja, od 12.5 do 21. tjedna nakon začeća (TNZ). Metodom po Nisslu vizualizirali smo granice privremenih fetalnih zona, dok smo imunohistokemijskom i imunofluorescencijskom metodom vizualizirali CELF1, te pratili obrazac njegove ekspresije u moždanoj kori čeonog režnja čovjeka. Rezultati su pokazali kako je tijekom srednjeg fetalnog razdoblja CELF1 intenzivno eksprimiran u proliferativnim zonama moždane kore, te u kortikalnoj ploči odnosno subplate zoni.Human brain development is a very complex process that begins during the early embryonic period. The fetal cerebral cortex is composed of the transient fetal compartments which do not exist in an adult brain. From the ventricular to the pial surface of the cerebral wall, there is the ventricular zone, subventricular zone, intermediate zone, subplate zone, cortical plate and close to the pial surface - marginal zone. Ventricular and subventricular zone are proliferative compartments where neurons are born and then migrate to their final destination through the intermediate zone. Radial glia, type of fetal astrocytes, help newly born neurons in the process of migration. The subplate zone is formed between the 12th and 15th postconceptional weeks (PCW), as one of the crucial compartments in cortical development. Subplate zone is a „waiting“ compartment for thalamocortical axons that are waiting to grow in the cortical plate and the site of intensive early synaptogenesis. In the 8th gestational week, the cortical plate is formed, which marks the transition from embryonic to fetal period. Cortical plate and subplate zone, together with the most superficial layer, so called the marginal zone, form the neocortical anlage. The aim of the study was to reveal the expression pattern of the RNA binding protein from the CELF family, called CELF1, during midfetal period. CELF1 plays an important role in RNA metabolism, such as translation, splicing, and regulation of the stability of the RNA molecule. Furthermore, CELF1 is involved in glutamatergic neuron identity during normal cortical development and in the pathogenesis of myotonic dystrophy. However, CELF1 expression pattern in human cerebral cortex is still unknown. In order to visualize the CELF1 expression pattern in the transient fetal cortical zones throughout midfetal period we used immunohistochemistry, immunofluorescence and histological Nissl staining as a cytoarchitectonic marker to delineate transient cortical compartments. Our results showed that during midfetal cortical development, CELF1 expression is enriched in the proliferative zone, followed by expression in the cortical plate and subplate zone

Expression pattern of the CELF1 protein in the frontal lobe during human fetal brain development

Razvoj mozga čovjeka je složen proces koji započinje tijekom ranog embrionalnog razdoblja. Moždana kora fetusa građena je od privremenih fetalnih zona koje ne postoje u moždanoj kori odraslog čovjeka. Proučavajući moždano tkivo, od ventrikularne površine (uz moždane komore) prema pijalnoj površini mogu se razaznati ventrikularna zona, subventrikularna zona, intermedijalna zona, subplate zona, kortikalna ploča i marginalna zona. Ventrikularna i subventrikularna zona jesu proliferativne zone u kojima se rađaju novi neuroni, a zatim slijedi proces radijalne migracije kroz intermedijalnu zonu, koji potpomaže radijalna glija, vrsta fetalnih astrocita. Između 12. i 15. tjedna gestacije javlja se subplate zona kao jedna od ključnih privremenih fetalnih zona za razvoj moždane kore. Subplate zona ima niz razvojnih funkcija, između ostalog, služi kao čekaonica za talamokortikalne aksone koji urastaju u kortikalnu ploču, te je mjesto intenzivne rane sinaptogeneze. U 8. tjednu embrionalnog razvoja nastaje kortikalna ploča koja obilježava prijelaz iz embrionalnog u fetalno razdoblje. Najpovršniji sloj fetalne moždane kore naziva se marginalna zona. Subplate, kortikalna ploča i marginalna zona zajedno čine razvojnu osnovu kore velikog mozga. Poznata je uloga RNA-vezujućeg proteina iz CELF obitelji, CELF1, tijekom normalnog razvoja mozga te u patogenezi miotonične distrofije. CELF1 ima niz uloga u metabolizmu RNA molekule, poput translacije, prekrajanja i regulacije stabilnosti RNA molekule. Nedavno je pokazano da je Celf1 regulator razvoja glutamatergičkih neurona putem translacijske represije Elavl4. Unatoč tome, ekspresijski obrazac CELF1 u moždanoj kori čovjeka nije poznat. Cilj diplomskog rada bio je istražiti obrazac ekspresije CELF1 u moždanoj kori čeonog režnja čovjeka tijekom srednje fetalnog razdoblja, od 12.5 do 21. tjedna nakon začeća (TNZ). Metodom po Nisslu vizualizirali smo granice privremenih fetalnih zona, dok smo imunohistokemijskom i imunofluorescencijskom metodom vizualizirali CELF1, te pratili obrazac njegove ekspresije u moždanoj kori čeonog režnja čovjeka. Rezultati su pokazali kako je tijekom srednjeg fetalnog razdoblja CELF1 intenzivno eksprimiran u proliferativnim zonama moždane kore, te u kortikalnoj ploči odnosno subplate zoni.Human brain development is a very complex process that begins during the early embryonic period. The fetal cerebral cortex is composed of the transient fetal compartments which do not exist in an adult brain. From the ventricular to the pial surface of the cerebral wall, there is the ventricular zone, subventricular zone, intermediate zone, subplate zone, cortical plate and close to the pial surface - marginal zone. Ventricular and subventricular zone are proliferative compartments where neurons are born and then migrate to their final destination through the intermediate zone. Radial glia, type of fetal astrocytes, help newly born neurons in the process of migration. The subplate zone is formed between the 12th and 15th postconceptional weeks (PCW), as one of the crucial compartments in cortical development. Subplate zone is a „waiting“ compartment for thalamocortical axons that are waiting to grow in the cortical plate and the site of intensive early synaptogenesis. In the 8th gestational week, the cortical plate is formed, which marks the transition from embryonic to fetal period. Cortical plate and subplate zone, together with the most superficial layer, so called the marginal zone, form the neocortical anlage. The aim of the study was to reveal the expression pattern of the RNA binding protein from the CELF family, called CELF1, during midfetal period. CELF1 plays an important role in RNA metabolism, such as translation, splicing, and regulation of the stability of the RNA molecule. Furthermore, CELF1 is involved in glutamatergic neuron identity during normal cortical development and in the pathogenesis of myotonic dystrophy. However, CELF1 expression pattern in human cerebral cortex is still unknown. In order to visualize the CELF1 expression pattern in the transient fetal cortical zones throughout midfetal period we used immunohistochemistry, immunofluorescence and histological Nissl staining as a cytoarchitectonic marker to delineate transient cortical compartments. Our results showed that during midfetal cortical development, CELF1 expression is enriched in the proliferative zone, followed by expression in the cortical plate and subplate zone

Early Regional Patterning in the Human Prefrontal Cortex Revealed by Laminar Dynamics of Deep Projection Neuron Markers

Early regional patterning and laminar position of cortical projection neurons is determined by activation and deactivation of transcriptional factors (TFs) and RNA binding proteins (RBPs) that regulate spatiotemporal framework of neurogenetic processes (proliferation, migration, aggregation, postmigratory differentiation, molecular identity acquisition, axonal growth, dendritic development, and synaptogenesis) within transient cellular compartments. Deep-layer projection neurons (DPN), subplate (SPN), and Cajal–Retzius neurons (CRN) are early-born cells involved in the establishment of basic laminar and regional cortical architecture; nonetheless, laminar dynamics of their molecular transcriptional markers remain underexplored. Here we aimed to analyze laminar dynamics of DPN markers, i.e., transcription factors TBR1, CTIP2, TLE4, SOX5, and RBP CELF1 on histological serial sections of the human frontal cortex between 7.5–15 postconceptional weeks (PCW) in reference to transient proliferative, migratory, and postmigratory compartments. The subtle signs of regional patterning were seen during the late preplate phase in the pattern of sublaminar organization of TBR1+/Reelin+ CRN and TBR1+ pioneering SPN. During the cortical plate (CP)-formation phase, TBR1+ neurons became radially aligned, forming continuity from a well-developed subventricular zone to CP showing clear lateral to medial regional gradients. The most prominent regional patterning was seen during the subplate formation phase (around 13 PCW) when a unique feature of the orbitobasal frontal cortex displays a “double plate” pattern. In other portions of the frontal cortex (lateral, dorsal, medial) deep portion of CP becomes loose and composed of TBR1+, CTIP2+, TLE4+, and CELF1+ neurons of layer six and later-born SPN, which later become constituents of the expanded SP (around 15 PCW). Overall, TFs and RBPs mark characteristic regional laminar dynamics of DPN, SPN, and CRN subpopulations during remarkably early fetal phases of the highly ordered association cortex development

Prenatal development of the human entorhinal cortex

Little is known about the development of the human entorhinal cortex (EC), a major hub in a widespread network for learning and memory, spatial navigation, high-order processing of object information, multimodal integration, attention and awareness, emotion, motivation, and perception of time. We analyzed a series of 20 fetal and two adult human brains using Nissl stain, acetylcholinesterase (AChE) histochemistry, and immunocytochemistry for myelin basic protein (MBP), neuronal nuclei antigen (NeuN), a pan-axonal neurofilament marker, and synaptophysin, as well as postmortem 3T MRI. In comparison with other parts of the cerebral cortex, the cytoarchitectural differentiation of the EC begins remarkably early, in the 10th week of gestation (w.g.). The differentiation occurs in a superficial magnocellular layer in the deep part of the marginal zone, accompanied by cortical plate (CP) condensation and multilayering of the deep part of CP. These processes last until the 13-14th w.g. At 14 w.g., the superficial lamina dissecans (LD) is visible, which divides the CP into the lamina principalis externa (LPE) and interna (LPI). Simultaneously, the rostral LPE separates into vertical cell-dense islands, whereas in the LPI, the deep LD emerges as a clear acellular layer. In the 16th w.g., the LPE remodels into vertical cell-dense and cell-sparse zones with a caudorostral gradient. At 20 w.g., NeuN immunoreactivity is most pronounced in the islands of layer II cells, whereas migration and differentiation inside-out gradients are seen simultaneously in both the upper (LPE) and the lower (LPI) pyramidal layers. At this stage, the EC adopts for the first time an adult-like cytoarchitectural organization, the superficial LD becomes discernible by 3T MRI, MBP-expressing oligodendrocytes first appear in the fimbria and the perforant path (PP) penetrates the subiculum to reach its molecular layer and travels along through the Cornu Ammonis fields to reach the suprapyramidal blade of the dentate gyrus, whereas the entorhinal-dentate branch perforates the hippocampal sulcus about 2-3 weeks later. The first AChE reactivity appears as longitudinal stripes at 23 w.g. in layers I and II of the rostrolateral EC and then also as AChE-positive in-growing fibers in islands of superficial layer III and layer II neurons. At 40 w.g., myelination of the PP starts as patchy MBP-immunoreactive oligodendrocytes and their processes. Our results refute the possibility of an inside-out pattern of the EC development and support the key role of layer II prospective stellate cells in the EC lamination. As the early cytoarchitectural differentiation of the EC is paralleled by the neurochemical development, these developmental milestones in EC structure and connectivity have implications for understanding its normal function, including its puzzling modular organization and potential contribution to consciousness content (awareness), as well as for its insufficiently explored deficits in developmental, psychiatric, and degenerative brain disorders