Abstract
Neuropathological conditions might affect adult granulogenesis in the adult human dentate gyrus. However, radial glial cells (RGCs) have not been well characterized during human development ...and aging. We have previously described progenitor and neuronal layer establishment in the hippocampal pyramidal layer and dentate gyrus from embryonic life until mid-gestation. Here, we describe RGC subtypes in the hippocampus from 13 gestational weeks (GW) to mid-gestation and characterize their evolution and the dynamics of neurogenesis from mid-gestation to adulthood in normal and Alzheimer's disease (AD) subjects. In the pyramidal ventricular zone (VZ), RGC density declined with neurogenesis from mid-gestation until the perinatal period. In the dentate area, morphologic and antigenic differences among RGCs were observed from early ages of development to adulthood. Density and proliferative capacity of dentate RGCs as well as neurogenesis were strongly reduced during childhood until 5 years, few DCX+ cells are seen in adults. The dentate gyrus of both control and AD individuals showed Nestin+ and/or GFAPδ+ cells displaying different morphologies. In conclusion, pools of morphologically, antigenically, and topographically diverse neural progenitor cells are present in the human hippocampus from early developmental stages until adulthood, including in AD patients, while their neurogenic potential seems negligible in the adult.
Objective
Facioscapulohumeral muscular dystrophy (FSHD) is linked to either contraction of D4Z4 repeats on chromosome 4 or to mutations in the SMCHD1 gene, both of which result in the aberrant ...expression of the transcription factor DUX4. However, it is still difficult to correlate these genotypes with the phenotypes observed in patients. Because we have recently shown that mice with disrupted Fat1 functions exhibit FSHD‐like phenotypes, we have investigated the expression of the human FAT1 gene in FSHD.
Methods
We first analyzed FAT1 expression in FSHD adult muscles and determined whether FAT1 expression was driven by DUX4. We next determined FAT1 expression levels in 64 muscles isolated from 16 control fetuses. These data were further complemented with analysis of Fat1 expression in developing mouse embryos.
Results
We demonstrated that FAT1 expression is independent of DUX4. Moreover, we observed that (1) in control fetal human biopsies or in developing mouse embryos, FAT1 is expressed at lower levels in muscles that are affected at early stages of FSHD progression than in muscles that are affected later or are nonaffected; and (2) in adult muscle biopsies, FAT1 expression is lower in FSHD muscles compared to control muscles.
Interpretation
We propose a revised model for FSHD in which FAT1 levels might play a role in determining which muscles will exhibit early and late disease onset, whereas DUX4 may worsen the muscle phenotype. Ann Neurol 2015;78:387–400
Jeune asphyxiating thoracic dystrophy (ATD) is an autosomal-recessive chondrodysplasia characterized by short ribs and a narrow thorax, short long bones, inconstant polydactyly, and trident ...acetabular roof. ATD is closely related to the short rib polydactyly syndrome (SRP) type III, which is a more severe condition characterized by early prenatal expression and lethality and variable malformations. We first excluded IFT80 in a series of 26 fetuses and children belonging to 14 families diagnosed with either ATD or SRP type III. Studying a consanguineous family from Morocco, we mapped an ATD gene to chromosome 11q14.3-q23.1 in a 20.4 Mb region and identified homozygous mutations in the cytoplasmic dynein 2 heavy chain 1 (DYNC2H1) gene in the affected children. Compound heterozygosity for DYNC2H1 mutations was also identified in four additional families. Among the five families, 3/5 were diagnosed with ATD and 2/5 included pregnancies terminated for SRP type III. DYNC2H1 is a component of a cytoplasmic dynein complex and is directly involved in the generation and maintenance of cilia. From this study, we conclude that ATD and SRP type III are variants of a single disorder belonging to the ciliopathy group.
Microglial cells penetrate into and scatter throughout the human cortical grey and white matter according to a specific spatiotemporal pattern during the first 2 trimesters of gestation. Routes of ...entry were quantitatively and qualitatively different from those identified in the diencephalon. Starting at 4.5 gestational weeks, amoeboid microglial cells, characterized by different antibodies as Iba1, CD68, CD45, and MHC-II, entered the cerebral wall from the ventricular lumen and the leptomeninges. Migration was mainly radial and tangential toward the immature white matter, subplate layer, and cortical plate, whereas pial cells populated the prospective layer I. The intraparenchymal vascular route of entry was detectable only from 12 gestational weeks. Interestingly, microglial cells accumulated in restricted laminar bands particularly at 19 to 24 gestational weeks among the corona radiata fibers rostrally, extending caudally in the immature white matter to reach the visual radiations. This accumulation of proliferating MIB1-positive microglia (as shown by MIB1-Iba1 double immunolabeling) was located at the site of white matter injury in premature neonates. The spatiotemporal organization of microglia in the immature white and grey matter suggests that these cells may play active roles in developmental processes and in injury to the developing brain.
To assess the prevalence, timing of diagnosis and infant mortality of congenital heart defects (CHD) with population-based data and using a classification that allows regrouping of the International ...Paediatric and Congenital Cardiac Code into a manageable number of categories based on anatomic and clinical criteria (ACC-CHD).
Population-based cohort study.
Greater Paris.
All cases (live births, terminations of pregnancy for foetal anomaly (TOPFA), foetal deaths) diagnosed prenatally, or up to 1 year of age in the birth cohorts, May 2005-April 2008, for women in Greater Paris (n=317 538 births). Diagnoses were confirmed in specialised centres and subsequently coded and classified into the categories of ACC-CHD by paediatric cardiologists in the study group.
The total number of CHD was 2867, including 2348 live births (82%), 466 TOPFA (16.2%) and 53 foetal deaths (1.8%). The total prevalence of CHD was 90 per 10 000. After exclusion of ventricular septal defects (VSD), 40% of 'isolated' CHD was diagnosed prenatally with about one half of the remaining diagnosed before 7 days of age. Nevertheless, one in five cases of these major CHD was diagnosed after the fourth week. Infant mortality of 'isolated' CHD-VSD excluded was 8.5% with 40% of deaths occurring after the fourth week of life. These outcomes varied substantially across categories of ACC-CHD.
Timing of diagnosis, TOPFA, risk and timing of infant mortality were highly variable across the categories of CHD in ACC-CHD, suggesting that it may be a useful measure of severity, and hence, predictor of outcomes of CHD.
Trisomy 13 or Patau syndrome (PS) is a well‐known aneuploidy characterized by a polymalformative syndrome. We described a large series of fetuses with PS and compared them with cases described in the ...literature, most of which were live‐born. In all, 42 fetuses, aged from 14 to 41 gestational weeks (GW), were examined. The main defects observed were similar to those described in live‐born patients: congenital heart defects (76%), holoprosencephaly spectrum anomalies including arhinencephaly and hypotelorism (74%), urinary tract anomalies (71%), ear anomalies (69%), postaxial polydactyly (67%), anogenital anomalies (60%), anophthalmos, and/or microphthalmos (53%), brachycephaly (45%), and oro‐facial clefts (45%). A duplication or triplication of at least one distal phalanx of the thumb or hallux was present in 38% of fetuses. This sign has only been reported previously in one patient in the literature. Fetal examination in trisomy 13, is thus, useful to complete the phenotype or to orient diagnosis toward trisomy 13 in the absence of cytogenetic analysis.
The molecular mechanisms underlying the formation of hippocampus are unknown in humans. To improve our knowledge of molecules that potentially regulate pyramidal neurogenesis and layering in various ...hippocampal fields, we investigated the expression of progenitor markers and cell fate molecules from gestational week (GW) 9 to GW 20. At GW 9, the progenitor cell compartment of the hippocampal formation mainly consisted of PAX6(+) cells in the ventricular zone. Between GW 9 and 11, a second germinal area, the subventricular zone (SVZ), was formed, as shown by TBR2 labeling. Postmitotic markers (TBR1, CTIP2, SATB2, and CUX1) might reflect the inside-out layering of the plate from GW 11 onwards. TBR1(+) neurons appeared in the deep plate, whereas CTIP2(+), SATB2(+), and CUX1(+) neurons occupied the upper layers. From GW 16, differences in layer segregation were observed between the ammonic and subicular plates. Moreover, an ammonic-to-subicular maturation gradient was observed in germinal/postmitotic areas. Taken together, these findings demonstrate for the first time the presence of an SVZ in the hippocampus of human fetuses and laminar differences in transcription factor expression in the pyramidal layer of the human ammonic and subicular plate, and provide new information to further investigate the connectivity of the hippocampal formation.
The human neonatal period is characterized by renal immaturity with impaired capacity to regulate water and sodium homeostasis, resembling partial aldosterone resistance. Because aldosterone effects ...are mediated by the mineralocorticoid receptor (MR), we postulated that this hormonal unresponsiveness could be related to low MR expression in the distal nephron. We measured aldosterone and renin levels in umbilical cord blood of healthy newborns. We used quantitative real-time PCR and immunohistochemistry to analyze the expression of MR and key players of the mineralocorticoid signaling pathway during human and mouse renal development. High aldosterone and renin levels were found at birth. MR mRNA was detected in mouse kidney at d 16 postcoitum, peaking at d 18 postcoitum, but its expression was surprisingly very low at birth, rising progressively afterward. Similar biphasic temporal expression was observed during human renal embryogenesis, with a transient expression between 15 and 24 wk of gestation but an undetectable immunoreactive MR in late gestational and neonatal kidneys. This cyclic MR expression was tightly correlated with the evolution of the 11β-hydroxysteroid dehydrogenase type 2 and the epithelial sodium channel α-subunit. In contrast, glucocorticoid and vasopressin receptors and aquaporin 2 followed a progressive and sustained evolution during renal maturation. Our study provides the first evidence for a low renal MR expression level at birth, despite high aldosterone levels, which could account for compromised postnatal sodium handling. Elucidation of regulatory mechanisms governing MR expression should lead to new strategies for the management of sodium waste in preterms and neonates.
The level of renal mineralocorticoid receptor expression level is low at birth in human and mouse, which could account for the physiological partial aldosterone resistance in neonates.
Cytomegalovirus-Induced Brain Malformations in Fetuses Teissier, Natacha; Fallet-Bianco, Catherine; Delezoide, Anne-Lise ...
Journal of neuropathology and experimental neurology,
2014-February, 2014-Feb, 2014-02-00, 20140201, Volume:
73, Issue:
2
Journal Article
Peer reviewed
Open access
ABSTRACTNeurologic morbidity associated with congenital cytomegalovirus (CMV) infection is a major public health concern. The pathogenesis of cerebral lesions remains unclear. We report the ...neuropathologic substrates, the immune response, and the cellular targets of CMV in 16 infected human fetal brains aged 23 to 28.5 gestational weeks. Nine cases were microcephalic, 10 had extensive cortical lesions, 8 had hippocampal abnormalities, and 5 cases showed infection of the olfactory bulb. The density of CMV-immunolabeled cells correlated with the presence of microcephaly and the extent of brain abnormalities. Innate and adaptive immune responses were present but did not react against all CMV-infected cells. Cytomegalovirus infected all cell types but showed higher tropism for stem cells/radial glial cells. The results indicate that 2 main factors influence the neuropathologic outcome at this stagethe density of CMV-positive cells and the tropism of CMV for stem/progenitor cells. This suggests that the large spectrum of CMV-induced brain abnormalities is caused not only by tissue destruction but also by the particular vulnerability of stem cells during early brain development. Florid infection of the hippocampus and the olfactory bulb may expose these patients to the risk of neurocognitive and sensorineural handicap even in cases of infection at late stages of gestation.
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