Characterization of the HeCo Mutant Mouse: A New Model of Subcortical Band Heterotopia Associated with Seizures and Behavioral Deficits

In human, neuronal migration disorders are commonly associated with developmental delay, mental retardation, and epilepsy. We describe here a new mouse mutant that develops a heterotopic cortex (HeCo) lying in the dorsolateral hemispheric region, between the homotopic cortex (HoCo) and subcortical white matter. Cross-breeding demonstrated an autosomal recessive transmission. Birthdating studies and immunochemistry for layer-specific markers revealed that HeCo formation was due to a transit problem in the intermediate zone affecting both radially and tangentially migrating neurons. The scaffold of radial glial fibers, as well as the expression of doublecortin is not altered in the mutant. Neurons within the HeCo are generated at a late embryonic age (E18) and the superficial layers of the HoCo have a correspondingly lower cell density and layer thickness. Parvalbumin immunohistochemistry showed the presence of gamma-aminobutyric acidergic cells in the HeCo and the mutant mice have a lowered threshold for the induction of epileptic seizures. The mutant showed a developmental delay but, in contrast, memory function was relatively spared. Therefore, this unique mouse model resembles subcortical band heterotopia observed in human. This model represents a new and rare tool to better understand cortical development and to investigate future therapeutic strategies for refractory epileps

Contribution à l'étude de la structuration du diencéphale ventral de rat au cours du développement

Pendant une période précoce de son développement, le système nerveux central (SNC) est caractérisé par l'apparition de segments transversaux organisés le long du tube nerveux : les neuromères. Il a été montré qu'au sein des neuromères (prosomères pour le diencéphale), les progéniteurs neuronaux sont le siège de l'expression combinée et localisée de gènes spécifiques indispensables à la maturation des structures ou de certaines populations neuronales. Cependant, dans le diencéphale des mammifères, l'étude de l'expression de gènes du développement ne suffit pas à élucider les frontières de prosomères potentiels, qui restent donc très discutées. - Nos travaux concernent l'hypothalamus latéral postérieur de rat, où sont notamment localisées deux populations neuronales impliquées dans des réponses similaires (cycles veille-sommeil, prise alimentaire) et projetant dans l'ensemble du SNC : les neurones à hypocrétine (Hcrt) et les neurones producteurs de l'hormone de mélano-concentration (MCH). La distribution de ces deux populations neuronales ne respecte pas les frontières cytoarchitectoniques classiques de l'hypothalamus. Ainsi la distribution des neurones à MCH est restreinte à ladite zone à MCH , qui dérive d'un territoire particulier du neuroépithélium germinatif, et au sein de laquelle ont été individualisées au moins deux sous-populations définies en fonction de leur date de naissance et de leur phénotype chimique. Par ailleurs, les neurones à MCH sont détectés précocément au cours du développement. Nous avons donc utilisé une approche développementale pour essayer de comprendre la signification anatomique de la distribution des neurones à MCH, qui évoque certaines distributions spatiotemporelles de gènes du développement. - Les neurones à Hcrt étant colocalisés avec les neurones à MCH, nous avons tout d'abord voulu déterminer leur date de naissance et comparer ces résultats à ceux concernant la genèse des neurones à MCH. En utilisant la méthode au 5-bromo-2'-deoxyuridine (BrdU) et une technique de double marquage immunohistochimique BrdU/Hcrt, nous avons montré que 70% des neurones à Hcrt naissent au 12ème jour de vie embryonnaire. Les neurones à Hcrt sont générés en un pic étroit, ce qui explique leur distribution dans une aire incluse dans celle des neurones à MCH. Ce pic est encadré par ceux des deux sous-populations MCH, ce qui suggère que les neurones à Hcrt pourraient envoyer des collatérales à la fois vers le cortex et la moelle épinière. - Cette étude visait également à analyser les profils d'expression de cinq gènes du développement impliqués dans la mise en place du diencéphale (Pax6, Nkx2.1, Nkx2.2, DIx et Oln) et de les comparer à la distribution des neurones à MCH ainsi qu'aux premiers tractus de fibres. Par immunohistochimie et hybridation in situ, nous avons pu confirmer que la zone à MCH naît et se différencie dans un territoire caractérisé par l'expression d'une combinaison spécifique de facteurs de transcription. Ainsi, dès la naissance des premières cellules du manteau, au moins trois des gènes étudiés sont clairement exprimés dans ce territoire : il s'agit de Nkx2.l, Nkx2.2 et DIx. Cette zone à MCH est également adjacente au premier tractus longitudinal du diencéphale ou tractus post-opticus, issu de neurones de la région rétrochiasmatique. Par ailleurs, nous supposons l'existence d'un effet répressif, direct ou indirect, du gène Pax6. Notons que chez les souris homozygotes Pax6-/-, le gène MCH est exprimé de façon ectopique dans les aires du thalamus ventral. - Ce travail comporte la description de la distribution de ces facteurs de transcription et des premiers tractus de fibres dans le diencéphale ventral de rat. Cette analyse détaillée était indispensable à l'interprétation de nos données concernant les neurones à MCH et visait également à accéder à une meilleure compréhension de l'organisation anatomique de l'hypothalamus.Hypocretin (Hcrt)-neurons and melanin-concentrating hormone (MCH)-neurons are co-Iocalized in perifornical parts of the lateral hypothalamus. Both neuron populations project throughout the central nervous system and are involved in similar functions (sleep and feeding). - The birth date of Hcrt-containing neurons was analysed using the bromodeoxyuridine method in the rat. The results indicate that these neurons are generated between embryonic days 11 (E11) and E14, with a sharp peak on E12. This spatiotemporal pattern of genesis contrasts with that of the co-distributed neurons producing MCH in the lateral hypothalamic area, which have been described as generated in one large peak from E10 to E16. These observations may be linked to the relative distribution area of both populations. - Neurons expressing MCH are detected early during ontogenesis in the rat and are observed in a specific part of the hypothalamus. ln order to understand this observation, the developmental differentiation of these neurons in the embryonic brain was compared to the expression of key transcription factors involved in the diencephalic segmentation and the differentiation of primary tracts. MCH cell bodies are generated in an area characterized by a specific combination of gene expression : Nkx2.I, Nkx2.2 and Dix. These cells migrate away from the ventricular layer and settle, as the tractus postopticus and the medial forebrain bundle differentiate. The significance of these observations on distinct projection patterns of MCH neuron subpopulations is then discussed. - Finally, in late embryonic brains of mice carrying a mutation for the Pax6 gene, we observed an ectopic expression of the MCH peptide in the ventral thalamus, suggesting that Pax6 may have a repressive effect on the MCH phenotype differentiation.BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

A protocol to isolate and qualify purified human preantral follicles in cases of acute leukemia, for future clinical applications

Abstract Background Autotransplantation of cryopreserved ovarian cortex can be associated with a risk of cancer cell reseeding. This issue could be eliminated by grafting isolated preantral follicles. Collagenase NB6 is an enzyme produced under good manufacturing practices (GMP) in compliance with requirements for tissue engineering and transplantation in humans and thus can be used to isolate preantral follicles from ovarian tissue in the framework of further clinical applications. Multicolor flow cytometry is an effective tool to evaluate the potential contamination of follicular suspensions by leukemic cells. Methods The efficiency of collagenase NB6 was evaluated in comparison to collagenase type IA and Liberase DH, in terms of yield, morphology and viability. A short-term in vitro culture of follicles isolated with collagenase NB6 was conducted for 3 days in a fibrin matrix. A modelization procedure was carried out to detect the presence of leukemic cells in follicular suspensions using multicolor flow cytometry (MFC). Results No statistical differences were found between collagenase NB6, Liberase DH (p = 0.386) and collagenase type IA (p = 0.171) regarding the number of human preantral follicles isolated. The mean diameter of isolated follicles was significantly lower with collagenase NB6 (p < 0.0001). The survival rate of isolated follicles was 93.4% (n = 272) using collagenase NB6 versus 94.9% (n = 198) with Liberase DH and 92.6% (n = 298) using collagenase type IA. Even after 3 days of in vitro culture in a fibrin scaffold, most of the isolated follicles were still alive after using collagenase NB6 (90.7% of viable follicles; n = 339). The rate of isolated Ki67-positive follicles was 29 ± 9.19% before culture and 45 ± 1.41% after 3 days. In 23 out of 24 follicular suspensions analyzed, the detection of leukemic cells by MFC was negative. The purification had no significant impact on follicle viability. Conclusion The isolation and purification of human preantral follicles were performed following good manufacturing practices for cell therapy. Multicolor flow cytometry was able to confirm that final follicular suspensions were free from leukemic cells. This safe isolation technique using collagenase NB6 can be considered for future clinical applications

Validation of an automated technique for ovarian cortex dissociation: isolation of viable ovarian cells and their qualification by multicolor flow cytometry

Abstract Background Ovarian tissue cryopreservation is a technique for fertility preservation addressed to prepubertal girls or to patients for whom no ovarian stimulation is possible before initiation of gonadotoxic treatments. Autotransplantation of frozen-thawed ovarian tissue is the only available option for reuse but presents some limitations: ischemic tissue damages post-transplant and reintroduction of malignant cells in cases of cancer. It is therefore essential to qualify ovarian tissue before autograft on a functional and oncological point of view. Here, we aimed to isolate viable cells from human ovarian cortex in order to obtain an ovarian cell suspension analyzable by multicolor flow cytometry. Methods Ovarian tissue (fresh or frozen-thawed), from patients with polycystic ovarian syndrome (reference tissue) and from patients who underwent ovarian tissue cryopreservation, was used for dissociation with an automated device. Ovarian tissue-dissociated cells were analyzed by multicolor flow cytometry; the cell dissociation yield and viability were assessed. Two automated dissociation protocols (named laboratory and commercial protocols) were compared. Results The effectiveness of the dissociation was not significantly different between reference ovarian tissue (1.58 × 106 ± 0.94 × 106 viable ovarian cells per 100 mg of ovarian cortex, n = 60) and tissue from ovarian tissue cryopreservation (1.70 × 106 ± 1.35 × 106 viable ovarian cells, n = 18). However, the viability was slightly different for fresh ovarian cortex compared to frozen-thawed ovarian cortex whether we used reference tissue (p = 0.022) or tissue from ovarian cryopreservation (p = 0.018). Comparing laboratory and commercial protocols, it appeared that cell yield was similar but cell viability was significantly improved when using the commercial protocol (81.3% ± 12.3% vs 23.9% ± 12.5%). Conclusion Both dissociation protocols allow us to isolate more than one million viable cells per 100 mg of ovarian cortex, but the viability is higher when using the commercial dissociation kit. Ovarian cortex dissociation is a promising tool for human ovarian cell qualification and for ovarian residual disease detection by multicolor flow cytometry

Primary Progenitor Muscle Cells for Regenerative Medicine: Standardization of Therapeutic Protocols and Optimized In Vivo Murine Model For Volumetric Muscle Loss

Skeletal muscle tissue engineering constitutes an emerging therapeutic repair strategy aiming for structural and functional restoration following traumatic injury, deep burns, congenital malformation or surgical tumor removal. As for similar musculoskeletal acute and degenerative affections, allogenic progenitor cell therapy represents a promising clinical approach to synergistically supplement traditional surgical care. Preliminary studies have established the adequation of primary human fetal muscle progenitors (hFMPs) for applications in regenerative medicine. Such therapeutic cell sources combined with bioresorbable scaffolds optimally integrate in murine muscle injury models without causing immune rejection. The present work aimed at functional recovery assessment following standardized application of hFMPs in an optimized murine skeletal muscle wound model. Cryopreserved hFMPs were initiated and culture-expanded before seeding in equine collagen scaffolds. Gastrocnemius muscles of C57BL/6 mice were injured following a standardized protocol. Resulting volume defects were treated with collagen constructs yielding marked hFMPs (105 cells/construct), constructs alone or remained untreated, assorted to appropriate internal controls. Histological and biomechanical analysis of muscle tissue and integrated therapeutic constructs were performed at the time of surgery and during the following 8 weeks. Both therapeutic protocols and in vivo models were optimized and standardized, based on internal experience concerning progenitor cell therapies for cutaneous reconstruction. Results indicated significantly improved function in all study groups treated with hFMPs. In particular, absolute peak twitch tensions measured on injured muscles were relatively superior in value at different time points after progenitor cell therapy application. Engraftment of hFMPs in murine wounded muscle enabled xenogeneic tissue repair stimulation and overall improvement of functional recovery. The combination of murine muscle wound model and therapeutic cell delivery method was determined as optimal for assessing muscle functional characteristic evolution notwithstanding severe tissue injury by volume loss. Such data support further translational investigation of allogenic progenitor cell therapy for human muscle defects and injuries

Live birth after ovarian tissue autograft in a patient with sickle cell disease treated by allogeneic bone marrow transplantation.

International audienceOBJECTIVE: To report the first case of restoration of ovarian activity and live birth after cryopreserved ovarian tissue autograft in a patient without cancer treated by allogeneic bone marrow transplantation. DESIGN: Case report. SETTING: University hospital. PATIENT(S): One woman with homozygous sickle cell anemia. INTERVENTION(S): An orthotopic autotransplantation of ovarian cortical strips was performed after freeze-thawing. MAIN OUTCOME MEASURE(S): Cryopreservation of ovarian tissue, bone marrow transplantation, ovarian autograft, and restoration of ovarian function. RESULT(S): In autumn 2005, biopsy samples of ovarian tissue were cryopreserved before chemotherapy followed by bone marrow transplantation. In spring 2008, because the patient had been menopausal for 2.5 years as a result of the conditioning therapy, an orthotopic autotransplantation of thawed ovarian cortex was performed. The patient conceived spontaneously in a natural cycle in autumn 2008, and delivered a healthy female child in June 2009. CONCLUSION(S): Cryopreservation of ovarian tissue with subsequent autotransplantation is an emerging procedure for preserving the fertility of young patients with a high risk of premature ovarian failure (POF) resulting from gonadotoxic treatment. This case opens up new perspectives in cases of nonmalignant diseases

A novel force sensing platform using passive magnetic springs for mechanical characterisation of human oocytes

International audienceThis article presents a novel low cost force sensing platform for the mechanical characterisation of human oocytes. This platform is compatible with the specific context of Assisted Reproductive Technology (ART). The oocyte is placed inside a standard Petri dish filled with a culture medium. It is immobilized using a holding pipette. The disposable parts used to mechanically test each oocyte are made of glass. This configuration is very similar to the one used in IntraCytoplasmic Sperm Injection protocol excepted that the injection pipette is replaced by a glass indenter. This platform uses two passive and linear magnetic springs to measure the nanoforce applied to the oocyte. The stabilisation of the unstable magnetic springs is passively achieved using the reaction force generated by the compressed oocyte. Some preliminary results obtained with an experimental platform are presented. The global magnetic stiffness of the indenter, evaluated by simulation and experimentally identified, is about 0.0013 N m−1

Development of Ovarian Tissue Autograft to Restore Ovarian Function: Protocol for a French Multicenter Cohort Study

International audienceDERR1-10.2196/12944.Sterility is a major late effect of radiotherapy and chemotherapy treatments. Iatrogenic sterility is often permanent and greatly impacts long-term quality of life. Ovarian tissue cryopreservation (OTC) performed before gonadotoxic treatments with subsequent autograft is a method of fertility preservation available for girls and women. Its application in prepubertal girls is of particular value as it is the only possible approach in this patient group. In addition, it does not require a delay in cancer therapy and no ovarian stimulation is needed.ClinicalTrials.gov NCT02846064; https://clinicaltrials.gov/ct2/show/NCT02846064

Development of posterior hypothalamic neurons enlightens a switch in the prosencephalic basic plan.

In rats and mice, ascending and descending axons from neurons producing melanin-concentrating hormone (MCH) reach the cerebral cortex and spinal cord. However, these ascending and descending projections originate from distinct sub-populations expressing or not "Cocaine-and-Amphetamine-Regulated-Transcript" (CART) peptide. Using a BrdU approach, MCH cell bodies are among the very first generated in the hypothalamus, within a longitudinal cell cord made of earliest delaminating neuroblasts in the diencephalon and extending from the chiasmatic region to the ventral midbrain. This region also specifically expresses the regulatory genes Sonic hedgehog (Shh) and Nkx2.2. First MCH axons run through the tractus postopticus (tpoc) which gathers pioneer axons from the cell cord and courses parallel to the Shh/Nkx2.2 expression domain. Subsequently generated MCH neurons and ascending MCH axons differentiate while neurogenesis and mantle layer differentiation are generalized in the prosencephalon, including telencephalon. Ascending MCH axons follow dopaminergic axons of the mesotelencephalic tract, both being an initial component of the medial forebrain bundle (mfb). Netrin1 and Slit2 proteins that are involved in the establishment of the tpoc and mfb, respectively attract or repulse MCH axons.We conclude that first generated MCH neurons develop in a diencephalic segment of a longitudinal Shh/Nkx2.2 domain. This region can be seen as a prosencephalic segment of a medial neurogenic column extending from the chiasmatic region through the ventral neural tube. However, as the telencephalon expends, it exerts a trophic action and the mfb expands, inducing a switch in the longitudinal axial organization of the prosencephalon