c-jun is differentially expressed in embryonic and adult neural precursor cells

c-jun, a major component of AP-1 transcription factor, has a wide variety of functions. In the embryonic brain, c-jun mRNA is abundantly expressed in germinal layers around the ventricles. Although the subventricular zone (SVZ) of the adult brain is a derivative of embryonic germinal layers and contains neural precursor cells (NPCs), the c-jun expression pattern is not clear. To study the function of c-jun in adult neurogenesis, we analyzed c-jun expression in the adult SVZ by immunohistochemistry and compared it with that of the embryonic brain. We found that almost all proliferating embryonic NPCs expressed c-jun, but the number of c-jun immunopositive cells among proliferating adult NPCs was about half. In addition, c-jun was hardly expressed in post-mitotic migrating neurons in the embryonic brain, but the majority of c-jun immunopositive cells were tangentially migrating neuroblasts heading toward the olfactory bulb in the adult brain. In addition, status epilepticus is known to enhance the transient proliferation of adult NPCs, but the c-jun expression pattern was not significantly affected. These expression patterns suggest that c-jun has a pivotal role in the proliferation of embryonic NPCs, but it has also other roles in adult neurogenesis

Alterations of circulating endothelial cell and endothelial progenitor cell counts around the ovulation.

Context:Circulating endothelial cells (CECs) and progenitor cells (CEPs) have been intensively studied as a promising tool for treating ischemic diseases and monitoring cancer treatments, but how the menstrual cycle affects the variation in their counts remains unclear. Objective:The aims of the study were to determine the influence of the menstrual cycle on the number of CECs and CEPs and to investigate the association of their counts with circulating hormones and angiogenesis-associated factors. Design:CEP and CEC counts by flow cytometry and the CellSearch system and circulating factor levels were measured eight times during the menstrual cycle in 18 volunteers. The menstrual cycle was divided into six phases based on hormone concentrations. Results:CEP counts peaked in the periovulatory and middle luteal phases with a drop in the early luteal phase. CEC counts showed no significant variation. There were significant correlations between the CEP counts and the serum concentrations of estradiol (E2), LH, and granulocyte colony-stimulating factor (G-CSF) (P < 0.0001, P < 0.0001, and P = 0.01, respectively). The difference in CEP counts between two adjacent phases was significantly correlated with that in E2, LH, G-CSF, and serum vascular endothelial growth factor (P < 0.0001, P < 0.0001, P = 0.02, and P = 0.006, respectively). Conclusion:CEP counts peaked in the periovulatory and middle luteal phases, with a drop in the early luteal phase, and were correlated with serum E2, LH, and G-CSF concentrations. Consideration of the variation in CEP counts would be important for the clinical application of CEPs

Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population

Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer-Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1, 995). Eleven breast cancer susceptibility genes were analyzed using target-capture sequencing in a previous study; the PGV prevalence in BRCA1, BRCA2, and PALB2 was 0.75%, 3.1%, and 0.45%, respectively. Significant associations were found between the presence of BRCA PGVs and early disease onset, number of familial cancer cases (up to third-degree relatives), triple-negative breast cancer patients under the age of 60, and ovarian cancer history (all P < .0001). In total, 816 patients (40.9%) satisfied the National Comprehensive Cancer Network (NCCN) guidelines for recommending multigene testing. The sensitivity and specificity of the NCCN criteria for discriminating PGV carriers from noncarriers were 71.3% and 60.7%, respectively. The TC model showed good discrimination for predicting BRCA PGVs (area under the curve, 0.75; 95% confidence interval, 0.69-0.81). Furthermore, use of the TC model with an optimized cutoff of TC score ≥0.16% in addition to the NCCN guidelines improved the predictive efficiency for high-risk groups (sensitivity, 77.2%; specificity, 54.8%; about 11 genes). Given the influence of ethnic differences on prediction, we consider that further studies are warranted to elucidate the role of environmental and genetic factors for realizing precise prediction

Developing a mouse model of acute encephalopathy using low-dose lipopolysaccharide injection and hyperthermia treatment

Acute encephalopathy (AE) is mainly reported in East Asia and, in most cases, results from pediatric viral infections, leading to fever, seizure, and loss of consciousness. Cerebral edema is the most important pathological symptom of AE. At present, AE is classified into four categories based on clinical and pathophysiological features, and cytokine storm-induced AE is the severest among them. The pathogenesis of AE is currently unclear; this can be attributed to the lack of a simple and convenient animal model for research. Here, we hypothesized that the induction of systemic inflammation using lipopolysaccharide (LPS) injection followed by hyperthermia (HT) treatment can be used to develop an animal model of cytokine storm-induced AE. Postnatal eight-day-old mouse pups were intraperitoneally injected with low-dose LPS (50 or 100 µg/kg) followed by HT treatment (41.5°C, 30 min). Histological analysis of their brains was subsequently performed. Fluorescein isothiocyanate assay combined with immunohistochemistry was used to elucidate blood–brain barrier (BBB) disruption. LPS (100 µg/kg) injection followed by HT treatment increased BBB permeability in the cerebral cortex and induced microglial activation. Astrocytic clasmatodendrosis was also evident. The brains of some pups exhibited small ischemic lesions, particularly in the cerebral cortex. Our results indicate that a low-dose LPS injection followed by HT treatment can produce symptoms of cytokine storm-induced AE, which is observed in diseases, such as acute necrotizing encephalopathy and hemorrhagic shock and encephalopathy syndrome. Thus, this mouse model can help to elucidate the pathogenetic mechanisms underlying AE

Identification of NeuN immunopositive cells in the adult mouse subventricular zone

In the adult rodent subventricular zone (SVZ), there are neural stem cells (NSCs) and the specialized neurogenic niche is critical to maintain their stemness. To date, many cellular and noncellular factors that compose the neurogenic niche and markers to identify subpopulations of Type A cells have been confirmed. In particular, neurotransmitters regulate adult neurogenesis and mature neurons in the SVZ have been only partially analyzed. Moreover, Type A cells, descendants of NSCs, are highly heterogeneous and more molecular markers are still needed to identify them. In the present study, we systematically classified NeuN, commonly used as a marker of mature and immature post‐mitotic neurons, immunopositive (+) cells within the adult mouse SVZ. These SVZ‐NeuN+ cells (SVZ‐Ns) were mainly classified into two types. One was mature SVZ‐Ns (M‐SVZ‐Ns). Neurochemical properties of M‐SVZ‐Ns were similar to those of striatal neurons, but their birth date and morphology were different. M‐SVZ‐Ns were generated during embryonic and early postnatal stages with bipolar peaks and extended their processes along the wall of the lateral ventricle. The second type was small SVZ‐Ns (S‐SVZ‐Ns) with features of Type A cells. They expressed not only markers of Type A cells, but also proliferated and migrated from the SVZ to the olfactory bulb. Furthermore, S‐SVZ‐Ns could be classified into two types by their spatial locations and glutamic acid decarboxylase 67 expression. Our data indicate that M‐SVZ‐Ns are a new component of the neurogenic niche and S‐SVZ‐Ns are newly identified subpopulations of Type A cells