23 research outputs found
PlexinA4-Semaphorin3A mediated crosstalk between main cortical interneuron classes is required for superficial interneurons lamination
No full textWe demonstrate that the two main classes of interneurons (INs) communicate during cortical development. MGE-derived INs first colonize deep layers and serve as guidepost for later-arriving HTR3A+ INs. This process relies on PlexinA4 and Semaphorin3A signaling and is critical for the proper distribution of inhibitory neurons across layers.
Data here is files containing manual counting of neurons in the mouse somatosensory cortex at different ages (details are included in each of them). Data in 3 contains area measurements of growth cones after embryonic dissociated cell cultures. Data in 4 and 6 contains dynamic tracking of cells after time-lapse imaging. For each excel file, an associated prism file contains related statistical analyses
PlexinA4-Semaphorin3A mediated crosstalk between main cortical interneuron classes is required for superficial interneurons lamination
No full textWe demonstrate that the two main classes of interneurons (INs) communicate during cortical development. MGE-derived INs first colonize deep layers and serve as guidepost for later-arriving HTR3A+ INs. This process relies on PlexinA4 and Semaphorin3A signaling and is critical for the proper distribution of inhibitory neurons across layers.
Data here is files containing manual counting of neurons in the mouse somatosensory cortex at different ages (details are included in each of them). Data in 3 contains area measurements of growth cones after embryonic dissociated cell cultures. Data in 4 and 6 contains dynamic tracking of cells after time-lapse imaging. For each excel file, an associated prism file contains related statistical analyses
Modelling and Refining Neuronal Circuits with Guidance Cues: Involvement of Semaphorins
No full textThe establishment of neuronal circuits requires neurons to develop and maintain appropriate connections with cellular partners in and out the central nervous system. These phenomena include elaboration of dendritic arborization and formation of synaptic contacts, initially made in excess. Subsequently, refinement occurs, and pruning takes places both at axonal and synaptic level, defining a homeostatic balance maintained throughout the lifespan. All these events require genetic regulations which happens cell-autonomously and are strongly influenced by environmental factors. This review aims to discuss the involvement of guidance cues from the Semaphorin family.UPMCCAB
Tau and Retromer Dataset 1
No full textMicroscopy and other data related to
Retromer deficiency enhances the truncation and toxicity of Tau
Jamshid Asadzadeh, Evelyne Ruchti, Wei Jiao, Greta Limoni, Catherine MacLachlan, Scott A. Small, Graham Knott, Ismael Santa-Maria and Brian D. McCabe.
Brain Mind Institute, EPFL, Switzerland - https://mccabelab.or
Tau and Retromer Dataset 2
No full textMicroscopy and other data related to
Retromer deficiency enhances the truncation and toxicity of Tau
Jamshid Asadzadeh, Evelyne Ruchti, Wei Jiao, Greta Limoni, Catherine MacLachlan, Scott A. Small, Graham Knott, Ismael Santa-Maria and Brian D. McCabe.
Brain Mind Institute, EPFL, Switzerland - https://mccabelab.or
Specification and integration of interneuron subtypes in the neocortex
No full textCortical microcircuit function relies on the coordinated activity of a large diversity of interneuron (IN) subtypes. These cells originate from discrete areas of the subpallium, namely the medial and caudal ganglionic eminences (MGE and CGE) and the preoptic area (POA). From these sites of origin, INs migrate long distances to reach the developing neocortex and integrate into the cortical microcircuits. Understanding the emergence of their molecular diversity and how they develop in the neocortex will provide important insights on the architecture of the mature circuit in health and disease. In my PhD project, I studied molecular mechanisms controlling the specification, migration and maturation of IN subclasses. In the first study, I aimed at identifying the developmental origin of a specific subclass of cortical IN called neurogliaform cells (NGCs). These cells are recruited by long-range connections, such as interhemispheric and thalamic projections, and are thought to be the effectors of a powerful inhibitory circuit by activating metabotropic GABAB receptors. Using in vivo lineage-tracing in mice, I found that NGCs originate from a pool of cells located in the POA, co-expressing the transcription factor Hmx3 and the serotonin receptor 3A (HTR3A). Through a combination of methods, I found that Hmx3-derived HTR3A+ cortical IN exhibited the molecular, morphological and electrophysiological profile of NGCs. Overall, these results indicate that NGCs are a distinct class of INs with a unique developmental trajectory. In the second study, I focused on mechanisms regulating laminar allocation of superficial neocortical INs. In a previous study, we found that HTR3A controls the migration and laminar positioning of superficial cortical INs, but molecular mechanisms remain unknown. Using a microarray screen on wild-type and Htr3a-KO INs, I identified PlexinA4 (PlxnA4) as a candidate gene possibly acting downstream the Htr3a and specifically upregulated during the phase of cortical plate invasion. Using in vitro and in vivo strategies, I found that PLXNA4 ligand SEMA3A has chemorepulsive effect on PLXNA4+/HTR3A+ superficial INs and that these effects are mediated by the PLXNA4/NRP1 receptor complex. Interestingly, SEMA3A was found to be secreted by deep layer INs, which do not express the HTR3A. Overall, these results suggest a new guidance mechanism for migrating HTR3A+ INs, involving a HTR3A-dependent upregulation of PLXNA4 in superficial cortical INs. These PLXNA4+/HTR3A+ cells will become gradually sensitive to the repulsive ligand SEMA3A, secreted by deep layer INs, and will preferentially settle into superficial ones. In the third study, I aimed at characterizing the role of the potassium/chloride cotransporter KCC2 in INs at early developmental stages. KCC2 plays a main role in driving GABAAR-mediated inhibition in the mature cortex, by tuning intracellular chloride concentration. Interestingly, it is upregulated in INs earlier than in excitatory cells. To determine the role of KCC2 in IN development, I aimed to selectively knock-out this cotransporter in cortical INs using cre-lox approach. Analyses of the somatosensory cortices indicated that IN-specific deletion of KCC2 significantly decreased the density of parvalbumin (PV)-expressing cells in recombined mice and non cell-autonomously affected the morphological maturation of pyramidal neurons. These results suggest an important role for KCC2 in the maturation of PV-expressing INs. Taken together, studies performed in this PhD thesis provide new insight on molecular mechanisms regulating the specification, migration and laminar allocation of cortical INs
Investigating the expression and function of CGE-derived interneurons
No full textGABAergic interneurons (INs) account for about 20-30% of the whole neuronal population in the neocortex and are crucial to establish inhibitory modulation in cortical microcircuits. A wide diversity of cortical interneuron subtypes are described in the neocortex and developmental studies have provided new insights on the classification of cortical interneuron subtypes. During development, cortical INs originate from distinct areas of the subpallium, more specifically from the medial (MGE) and caudal (CGE) ganglionic eminences. After their generation, from these specific subregions they first tangentially migrate into the pallium and then invade the cortical plate..
Author response: Neurogliaform cortical interneurons derive from cells in the preoptic area
No full textDelineating the basic cellular components of cortical inhibitory circuits remains a fundamental issue in order to understand their specific contributions to microcircuit function. It is still unclear how current classifications of cortical interneuron subtypes relate to biological processes such as their developmental specification. Here we identified the developmental trajectory of neurogliaform cells (NGCs), the main effectors of a powerful inhibitory motif recruited by long-range connections. Using in vivo genetic lineage-tracing in mice, we report that NGCs originate from a specific pool of 5-HT3AR-expressing Hmx3+ cells located in the preoptic area (POA). Hmx3-derived 5-HT3AR+ cortical interneurons (INs) expressed the transcription factors PROX1, NR2F2, the marker reelin but not VIP and exhibited the molecular, morphological and electrophysiological profile of NGCs. Overall, these results indicate that NGCs are a distinct class of INs with a unique developmental trajectory and open the possibility to study their specific functional contribution to cortical inhibitory microcircuit motifs.</jats:p
Xalitla limoni Santos-Silva and Skillman 2020, new species
No full textXalitla limoni Santos-Silva and Skillman, new species (Fig. 1–5) Description. Female. Head reddish-brown; mandibles reddish-brown except darkened inferior margin of outer side and black apical quarter; mouthparts reddish-brown except yellowish-brown apex of palpomeres; scape and pedicel orangish-brown; base of antennomere III slightly reddish-brown and remaining surface black; antennomeres IV–VI dark reddish-brown basally, gradually lighter toward apex, irregularly interspersed with blackish areas on anterior 2/3; antennomeres VII–XI mostly reddishbrown, with irregularly slightly darkened portions on central area. Prothorax reddish-brown, with anterior and posterior margins, and area around procoxal cavities blackish; ventral surface of meso- and metathorax reddish-brown, except darkened margins of coxae. Scutellum dark reddish-brown centrally, with margins blackish. Elytra orangish-brown on almost entire basal third, black on remaining surface. Profemora orangish-brown; meso- and metafemora dark reddish-brown, irregularly darker on some areas. Protibiae dark brown, with reddish-brown areas irregularly interspersed; meso- and metatibiae nearly black, with irregular reddish-brown areas interspersed. Pro- and mesotarsomeres I–IV mostly reddishbrown, and pro- and mesotarsomeres V dark brown, except reddish-brown claws (metatarsi missing). Abdominal ventrites black. Erect setae (depending on light intensity and angle) more yellowish-white. Head. Frons, vertex, and area behind eyes coarsely, abundantly punctate; with minute whitish setae emerging from punctures, except sides of frons with both, short and long, erect white setae emerging from some punctures, and sides of vertex with some long, erect white setae emerging from punctures; area behind antennal insertion with yellowish-white pubescence. Genae 0.68 times length of lower eye lobe; coarsely, abundantly punctate except apex smooth; with both, short and long, erect, sparse white setae, except apex glabrous. Gulamentum smooth, glabrous on posterior half; slightly depressed, coarsely striate-punctate, with short, erect, sparse white setae laterally, and long, erect white setae anteriorly. Postclypeus coarsely, shallowly punctate on wide central area (punctures distinctly finer than on frons), smooth laterally; with moderately long, erect, sparse white setae on punctate area, glabrous laterally, and with very long, erect white setae on each side of wide central area. Labrum with long, erect, sparse yellowish setae directed forward. Antennal tubercles gradually elevated from anterior area, then abruptly inclined posteriorly, with apex rounded; coarsely, shallowly punctate basally, smooth posteriorly; with a few short, nearly erect white setae on punctate area. Outer side of mandibles with long, erect, thick white setae on anterior half. In frontal view, distance between lower eye lobes 1.4 times length of scape (0.67 times distance between outer margins of eyes). Antennae 1.27 times elytral length, almost reaching posterior quarter of elytra. Scape slightly, gradually widened in basal third, nearly parallel-sided in posterior 2/3; with short, sparse, decumbent white setae dorsally, and long, erect, sparse white setae throughout. Pedicel with long, erect, sparse white setae throughout. Antennomere III with short, decumbent white pubescence on outer surface, absent on remaining surface, and long, erect, moderately sparse white setae throughout; antennomeres IV–XI with white pubescence not obscuring integument, more bristly dorsally on VI–XI, distinctly sparser on IV–V, especially ventrally, long, erect, sparse white setae ventrally, and a few long, erect white setae on dorsal apex of IV–V; and in lateral view, antennomere III arched. Antennal formula (ratio) based on antennomere III: scape = 0.53; pedicel = 0.13; IV = 0.26; V = 0.47; VI = 0.51; VII = 0.44; VIII = 0.35; IX = 0.30; X = 0.27; XI = 0.38. Thorax. Prothorax distinctly longer than wide, arched in lateral view, anterior and posterior constrictions well-marked. Pronotum coarsely, densely punctate, deeper, partially confluent on each side of area of posterior constriction, less distinct on center of area of posterior constriction; part of punctures with minute white setae; with long, erect white setae distinctly more abundant laterally. Sides of prothorax coarsely, abundantly punctate on wide central area, smooth anteriorly (this area gradually, distinctly widened toward prosternum), smooth posteriorly except striate area close to procoxal cavity; with long, erect, abundant white setae on punctate area, glabrous anteriorly and posteriorly. Prosternum coarsely, abundantly punctate on posterior 2/3 (punctures confluent close to procoxal cavities), somewhat rugosepunctate on narrow area close to anterior margin, slightly striate on remaining surface; with long, erect, white setae on posterior 2/3 and narrow anterior area. Prosternum strongly narrowed centrally. Mesoventrite somewhat depressed on wide anterocentral area, distinctly obliquely elevated toward mesoventral process; depressed area finely rugose-punctate, coarsely, sparsely punctate toward mesoventral process, smooth laterally; depressed area with minute, sparse yellowish-white pubescence; punctate area with long, erect, sparse white setae; smooth area glabrous. Mesoventral process with distinct tab at each side of apex. Mesanepisternum coarsely, abundantly punctate; nearly glabrous superiorly, with wide, dense white pubescent band close to mesepimeron. Metanepisternum glabrous on anterior 2/3, with dense white pubescence on posterior third. Metaventrite coarsely, moderately sparsely punctate, with dense white pubescence on each side of posterior third close to metanepisternum. Scutellum with dense white pubescence. Elytra. Coarsely, abundantly punctate on anterior 3/4, punctures finer, slightly sparser on posterior quarter; with long, erect white setae, slightly more abundant on posterior third; apex rounded. Legs. Femora pedunculate-clavate (peduncle gradually longer from profemora to metafemora); with long, erect, sparse white setae. Tibiae with long, erect, abundant white setae dorsally; with yellowishwhite bristly pubescence ventrally (yellower near apex), gradually denser toward apex, with long, erect white setae interspersed. Abdomen. Ventrites finely, sparsely punctate; with both, short and long, erect, sparse white setae. Apex of ventrite V rounded. Dimensions in mm. Total length, 6.10; prothoracic length, 1.45; anterior prothoracic width, 1.05; posterior prothoracic width, 0.90; maximum prothoracic width, 1.10; humeral width, 1.35; elytral length, 3.65. Type material. Holotype female from MEXICO, JALISCO: 2.5–5 km W José María Morelos, 7.VII.2018, F. Skillman and J. Limón col. (deposited in FSCA, formerly FWSC); Paratype female, same data except: 2 km W. on Rd to beach (JFLC). Etymology. Named for Juan Francisco Limón, good friend and avid cerambycid collector with whom the second author has shared numerous forays into the bush in search of new or unknown species. Remarks. Xalitla limoni sp. nov. is similar in appearance to the female of X. azteca Lane, 1959 (Fig. 6–9), but differs as follows: body stouter (Fig. 1); peduncle of profemora short (Fig. 2); eyes distinctly smaller (Fig. 5). In X. azteca, the body is slimmer (Fig. 6), peduncle of profemora is longer (Fig. 7), and eyes are distinctly larger (Fig. 9). The holotype is glued on a card-triangle with non-soluble glue. Thus, it was not possible to remove the insect from the card, due to the risk of damaging the specimen, to examine the metaventrite in detail.Published as part of Santos-Silva, Antonio & Frederick W. Skillman, Jr., 2020, Description of a new species of Xalitla Lane, 1959 (Cerambycidae: Cerambycinae: Neoibidionini) from western Mexico, pp. 1-9 in Insecta Mundi 2020 (765) on pages 3-4, DOI: 10.5281/zenodo.535348
Virgaurea limoni folia, Virga aurea et Solidago Saracenico, Herba Doria
No full text1. Nome scientifico: Solidago mexicana L.
(Asteraceae, compositae)
Nome attuale: Verga d\u27oro del Messico
2. Nome scientifico: Solidago virgaurea L.
(Asteraceae, Compositae)
Nome attuale: Verga d\u27oro
3. Nome scientifico: Senecio doria L.
(Asteraceae, Compositae)
Nome attuale: Senecio erba-dori
