Dexamethasone blocks astroglial differentiation from neural precursor cells

Effect of Multiple Sclerosis Cerebrospinal Fluid and Oligodendroglia Cell Line Environment on Human Wharton's Jelly Mesenchymal Stem Cells Secretome

Multiple sclerosis (MS) is a neurological disorder of autoimmune aetiology. Experimental therapies with the use of mesenchymal stem cells (MSCs) have emerged as a response to the unmet need for new treatment options. The unique immunomodulatory features of stem cells obtained from Wharton’s jelly (WJ-MSCs) make them an interesting research and therapeutic model. Most WJ-MSCs transplants for multiple sclerosis use intrathecal administration. We studied the effect of cerebrospinal fluid (CSF) obtained from MS patients on the secretory activity of WJ-MSCs and broaden this observation with WJ-MSCs interactions with human oligodendroglia cell line (OLs). Analysis of the WJ-MSCs secretory activity with use of Bio-Plex Pro™ Human Cytokine confirmed significant and diverse immunomodulatory potential. Our data reveal rich WJ-MSCs secretome with markedly increased levels of IL-6, IL-8, IP-10 and MCP-1 synthesis and a favourable profile of growth factors. The addition of MS CSF to the WJ-MSCs culture caused depletion of most proteins measured, only IL-12, RANTES and GM-CSF levels were increased. Most cytokines and chemokines decreased their concentrations in WJ-MSCs co-cultured with OLs, only eotaxin and RANTES levels were slightly increased. These results emphasize the spectrum of the immunomodulatory properties of WJ-MSCs and show how those effects can be modulated depending on the transplantation milieu.

Can stress promote the pathophysiology of brain metastases? A critical review of biobehavioral mechanisms

Chronic stress can promote tumor growth and progression through immunosuppressive effects and bi-directional interactions between tumor cells and their microenvironment. β-Adrenergic receptor signaling plays a critical role in mediating stress-related effects on tumor progression. Stress-related mechanisms that modulate the dissemination of tumor cells to the brain have received scant attention. Brain metastases are highly resistant to chemotherapy and contribute considerably to morbidity and mortality in various cancers, occurring in up to 20% of patients in some cancer types. Understanding the mechanisms promoting brain metastasis could help to identify interventions that improve disease outcomes. In this review, we discuss biobehavioral, sympathetic, neuroendocrine, and immunological mechanisms by which chronic stress can impact tumor progression and metastatic dissemination to the brain. The critical role of the inflammatory tumor microenvironment in tumor progression and metastatic dissemination to the brain, and its association with stress pathways are delineated. We also discuss translational implications for biobehavioral and pharmacological interventions.

Corticosteroids and Regional Variations in Thickness of the Human Cerebral Cortex across the Lifespan

Exposures to life stressors accumulate across the lifespan, with possible impact on brain health. Little is known, however, about the mechanisms mediating age-related changes in brain structure. We use a lifespan sample of participants (n = 21 251; 4-97 years) to investigate the relationship between the thickness of cerebral cortex and the expression of the glucocorticoid- and the mineralocorticoid-receptor genes (NR3C1 and NR3C2, respectively), obtained from the Allen Human Brain Atlas. In all participants, cortical thickness correlated negatively with the expression of both NR3C1 and NR3C2 across 34 cortical regions. The magnitude of this correlation varied across the lifespan. From childhood through early adulthood, the profile similarity (between NR3C1/NR3C2 expression and thickness) increased with age. Conversely, both profile similarities decreased with age in late life. These variations do not reflect age-related changes in NR3C1 and NR3C2 expression, as observed in 5 databases of gene expression in the human cerebral cortex (502 donors). Based on the co-expression of NR3C1 (and NR3C2) with genes specific to neural cell types, we determine the potential involvement of microglia, astrocytes, and CA1 pyramidal cells in mediating the relationship between corticosteroid exposure and cortical thickness. Therefore, corticosteroids may influence brain structure to a variable degree throughout life.

The Effect of Antenatal Betamethasone on White Matter Inflammation and Injury in Fetal Sheep and Ventilated Preterm Lambs

Antenatal administration of betamethasone (BM) is a common antecedent of preterm birth, but there is limited information about its impact on the acute evolution of preterm neonatal brain injury. We aimed to compare the effects of maternal BM in combination with mechanical ventilation on the white matter (WM) of late preterm sheep. At 0.85 of gestation, pregnant ewes were randomly assigned to receive intra-muscular (i.m.) saline (n = 9) or i.m. BM (n = 13). Lambs were delivered and unventilated controls (UVCSal, n = 4; UVCBM, n = 6) were humanely killed without intervention; ventilated lambs (VentSal, n = 5; VentBM, n = 7) were injuriously ventilated for 15 min, followed by conventional ventilation for 75 min. Cardiovascular and cerebral haemodynamics and oxygenation were measured continuously. The cerebral WM underwent assessment of inflammation and injury, and oxidative stress was measured in the cerebrospinal fluid (CSF). In the periventricular and subcortical WM tracts, the proportion of amoeboid (activated) microglia, the density of astrocytes, and the number of blood vessels with protein extravasation were higher in UVCBM than in UVCSal (p < 0.05 for all). During ventilation, tidal volume, mean arterial pressure, carotid blood flow, and oxygen delivery were higher in -VentBM lambs (p < 0.05 vs. VentSal). In the subcortical WM, microglial infiltration was increased in the VentSal group compared to UVCSal. The proportion of activated microglia and protein extravasation was higher in the VentBM group compared to VentSal within the periventricular and subcortical WM tracts (p < 0.05). CSF oxidative stress was increased in the VentBM group compared to UVCSal, UVCBM, and VentSal groups (p < 0.05). Antenatal BM was associated with inflammation and vascular permeability in the WM of late preterm fetal sheep. During the immediate neonatal period, the increased carotid perfusion and oxygen delivery in BM-treated lambs was associated with increased oxidative stress, microglial activation and microvascular injury.

A Logic Model of Neuronal-Glial Interaction Suggests Altered Homeostatic Regulation in the Perpetuation of Neuroinflammation

Aberrant inflammatory signaling between neuronal and glial cells can develop into a persistent sickness behavior-related disorders, negatively impacting learning, memory, and neurogenesis. While there is an abundance of literature describing these interactions, there still lacks a comprehensive mathematical model describing the complex feed-forward and feedback mechanisms of neural-glial interaction. Here we compile molecular and cellular signaling information from various studies and reviews in the literature to create a logically-consistent, theoretical model of neural-glial interaction in the brain to explore the role of neuron-glia homeostatic regulation in the perpetuation of neuroinflammation. Logic rules are applied to this connectivity diagram to predict the system's homeostatic behavior. We validate our model predicted homeostatic profiles against RNAseq gene expression profiles in a mouse model of stress primed neuroinflammation. A meta-analysis was used to calculate the significance of similarity between the inflammatory profiles of mice exposed to diisopropyl fluorophostphate (DFP) [with and without prior priming by the glucocorticoid stress hormone corticosterone (CORT)], with the equilibrium states predicted by the model, and to provide estimates of the degree of the neuroinflammatory response. Beyond normal homeostatic regulation, our model predicts an alternate self-perpetuating condition consistent with chronic neuroinflammation. RNAseq gene expression profiles from the cortex of mice exposed to DFP and CORT+DFP align with this predicted state of neuroinflammation, whereas the alignment to CORT alone was negligible. Simulations of putative treatment strategies post-exposure were shown to be theoretically capable of returning the system to a state of typically healthy regulation with broad-acting anti-inflammatory agents showing the highest probability of success. The results support a role for the brain's own homeostatic drive in perpetuating the chronic neuroinflammation associated with exposure to the organophosphate DFP, with and without CORT priming. The deviation of illness profiles from exact model predictions suggests the presence of additional factors or of lasting changes to the brain's regulatory circuitry specific to each exposure.

Regression of a glioblastoma multiforme: spontaneous versus a potential antineoplastic effect of dexamethasone and levetiracetam

Patients with grade IV astrocytoma or glioblastoma multiforme (GBM) have a median survival of <12 months, increased to 14.6 months by maximal safe resection with radiation and temozolamide. In the absence of chemotherapy, radiotherapy or chemoradiotherapy, spontaneous regression of GBM or regression while only being on dexamethasone (DEX) and levetiracetam (LEV) have seldom been reported. Here, we present a case of a patient who had significant regression of the GBM with DEX and LEV alone. In this study, we hypothesise a plausible antineoplastic role of DEX and or LEV in GBM and highlight molecular, preclinical and clinical studies supporting this role.

CD99 regulates neural differentiation of Ewing sarcoma cells through miR-34a-Notch-mediated control of NF-κB signaling

Sarcomas are mesenchymal tumors characterized by blocked differentiation process. In Ewing sarcoma (EWS) both CD99 and EWS-FLI1 concur to oncogenesis and inhibition of differentiation. Here, we demonstrate that uncoupling CD99 from EWS-FLI1 by silencing the former, nuclear factor-κB (NF-κB) signaling is inhibited and the neural differentiation program is re-established. NF-κB inhibition passes through miR-34a-mediated repression of Notch pathway. CD99 counteracts EWS-FLI1 in controlling NF-κB signaling through the miR-34a, which is increased and secreted into exosomes released by CD99-silenced EWS cells. Delivery of exosomes from CD99-silenced cells was sufficient to induce neural differentiation in recipient EWS cells through miR-34a inhibition of Notch-NF-κB signaling. Notably, even the partial delivery of CD99 small interfering RNA may have a broad effect on the entire tumor cell population owing to the spread operated by their miR-34a-enriched exosomes, a feature opening to a new therapeutic option.

Astroglial Plasticity Is Implicated in Hippocampal Remodelling in Adult Rats Exposed to Antenatal Dexamethasone

The long-term effects of antenatal dexamethasone treatment on brain remodelling in 3-month-old male Sprague Dawley rats whose mothers had been treated with dexamethasone were investigated in the present study. Dorsal hippocampus, basolateral amygdala and nucleus accumbens volume, cell numbers, and GFAP-immunoreactive astroglial cell morphology were analysed using stereology. Total brain volume as assessed by micro-CT was not affected by the treatment. The relative volume of the dorsal hippocampus (% of total brain volume) showed a moderate, by 8%, but significant reduction in dexamethasone-treated versus control animals. Dexamethasone had no effect on the total and GFAP-positive cell numbers in the hippocampal subregions, basolateral amygdala, and nucleus accumbens. Morphological analysis indicated that numbers of astroglial primary processes were not affected in any of the hippocampal subregions analysed but significant reductions in the total primary process length were observed in CA1 by 32%, CA3 by 50%, and DG by 25%. Mean primary process length values were also significantly decreased in CA1 by 25%, CA3 by 45%, and DG by 25%. No significant astroglial morphological changes were found in basolateral amygdala and nucleus accumbens. We propose that the dexamethasone-dependent impoverishment of hippocampal astroglial morphology is the case of maladaptive glial plasticity induced prenatally.

Caveolin-1 regulates genomic action of the glucocorticoid receptor in neural stem cells

While glucocorticoids (GCs) are used clinically to treat many conditions, their neonatal and prenatal usage is increasingly controversial due to reports of delayed adverse outcomes, especially their effects on brain development. Such alterations may reflect the impact of GCs on neural progenitor/stem cell (NPSC) function. We previously demonstrated that the lipid raft protein caveolin-1 (Cav-1) was required for rapid GC signaling in embryonic mouse NPSCs operating through plasma membrane-bound glucocorticoid receptors (GRs). We show here that genomic GR signaling in NPSCs requires Cav-1. Loss of Cav-1 impacts the transcriptional response of many GR target genes (e.g., the serum- and glucocorticoid-regulated kinase 1 gene) that are likely to mediate the antiproliferative effects of GCs. Microarray analysis of wild-type C57 or Cav-1-deficient NPSCs identified approximately 100 genes that are differentially regulated by GC treatment. These changes in hormone responsiveness in Cav-1 knockout NPSCs are associated with the loss of GC-regulated phosphorylation of GR at serine 211 but not at serine 226. Chromatin recruitment of total GR to regulatory regions of target genes such as Fkbp-5, RhoJ, and Sgk-1, as well as p211-GR recruitment to Sgk-1, are compromised in Cav-1 knockout NPSCs. Cav-1 is therefore a multifunctional regulator of GR in NPSCs influencing both rapid and genomic action of the receptor to impact cell proliferation.

Smac mimetic promotes glioblastoma cancer stem-like cell differentiation by activating NF-κB

Recently, a broader role of inhibitor of apoptosis (IAP) proteins besides their antiapoptotic functions has been described. Therefore, we investigated the effect of non-toxic concentrations of the small-molecule Smac mimetic BV6, which antagonizes IAP proteins, on differentiation of cancer stem-like cells (CSLCs) derived from primary glioblastoma (GBM) specimens. Here, we identify a novel function of BV6 in regulating differentiation of GBM CSLCs by activating NF-κB. BV6 at non-lethal doses stimulates morphological changes associated with the differentiation of GBM CSLCs. BV6 increases transcriptional activity, mRNA and protein levels of the astrocytic marker GFAP without altering expression of the neuronal marker β-III-tubulin, indicating that BV6 induces astrocytic differentiation of GBM CSLCs. Molecular studies reveal that BV6 triggers processing of the NF-κB subunit p100 to p52, nuclear translocation of p52 and p50 and increased NF-κB DNA-binding. Intriguingly, inhibition of NF-κB by overexpression of dominant-negative IκBα super-repressor (IκBα-SR) blocks the BV6-stimulated increase in GFAP and differentiation. Interestingly, this BV6-stimulated differentiation is associated with reduced expression of stemness markers such as CD133, Nanog and Sox2 in GBM CSLCs. In contrast, BV6 does not alter cell morphology, differentiation and expression of stemness markers in non-malignant neural stem cells. Importantly, BV6 treatment reduces clonogenicity of GBM CSLCs in vitro and in vivo, suppresses their tumorigenicity in orthotopic and subcutaneous mouse models and significantly increases the survival of mice. By identifying a novel role of BV6 in promoting differentiation of GBM CSLCs, these findings provide new insights into Smac mimetic-regulated non-apoptotic functions with important implications for targeting GBM CSLCs.

Corticosterone treatment results in enhanced release of peptidergic vesicles in astrocytes via cytoskeletal rearrangements

While the effect of stress on neuronal physiology is widely studied, its effect on the functionality of astrocytes is not well understood. We studied the effect of high doses of stress hormone corticosterone, on two physiological properties of astrocytes, i.e., gliotransmission and interastrocytic calcium waves. To study the release of peptidergic vesicles from astrocytes, hippocampal astrocyte cultures were transfected with a plasmid to express pro-atrial natriuretic peptide (ANP) fused with the emerald green fluorescent protein (ANP.emd). The rate of decrease in fluorescence of ANP.emd on application of ionomycin, a calcium ionophore was monitored. Significant increase in the rate of calcium-dependent exocytosis of ANP.emd was observed with the 100 nM and 1 μM corticosterone treatments for 3 h, which depended on the activation of the glucocorticoid receptor. ANP.emd tagged vesicles exhibited increased mobility in astrocyte culture upon corticosterone treatment. Increasing corticosterone concentrations also resulted in concomitant increase in the calcium wave propagation velocity, initiated by focal ATP application. Corticosterone treatment also resulted in increased GFAP expression and F-actin rearrangements. FITC-Phalloidin immunostaining revealed increased formation of cross linked F-actin networks with the 100 nM and 1 μM corticosterone treatment. Alternatively, blockade of actin polymerization and disruption of microtubules prevented the corticosterone-mediated increase in ANP.emd release kinetics. This study reports for the first time the effect of corticosterone on gliotransmission via modulation of cytoskeletal elements. As ANP acts on both neurons and blood vessels, modulation of its release could have functional implications in neurovascular coupling under pathophysiological conditions of stress.

Corticosteroids in brain cancer patients: benefits and pitfalls

Glucocorticoids have been used for decades in the treatment of brain tumor patients and belong to the most powerful class of agents in reducing tumor-associated edema and minimizing side effects and the risk of encephalopathy in patients undergoing radiation therapy. Unfortunately, corticosteroids are associated with numerous and well-characterized adverse effects, constituting a major challenge in patients requiring long-term application of corticosteroids. Novel antiangiogenic agents, such as bevacizumab (Avastin®), which have been increasingly used in cancer patients, are associated with significant steroid-sparing effects, allowing neuro-oncologists to reduce the overall use of corticosteroids in patients with progressive malignant brain tumors. Recent experimental studies have revealed novel insights into the mechanisms and effects of corticosteroids in cancer patients, including modulation of tumor biology, angiogenesis and steroid-associated neurotoxicity. This article summarizes current concepts of using corticosteroids in brain cancer patients and highlights potential pitfalls in their effects on both tumor and neural progenitor cells.

Cooperativity and complementarity: synergies in non-classical and classical glucocorticoid signaling

Glucocorticoids (GCs) are an ubiquitous class of steroid hormones that exert a wide array of physiological effects. Traditionally, GC action has been considered to primarily involve transcriptional effects following the binding of hormone to the glucocorticoid receptor (GR) and subsequent activation or repression of target genes. However, a number of findings suggest that cellular responses following GC exposure may be mediated by transcription-independent, or "non-classical," mechanisms. We have added to this growing body of work by recently uncovering a novel GC signaling pathway that operates through plasma membrane GRs to limit gap junction intercellular signaling and limit the proliferation of neural progenitor cells (NPCs). In this review, we highlight our current state of knowledge of non-classical GR signaling, in particular as it applies to neuronal function. Using NPCs as a cellular model, we speculate on the components of this non-classical pathway and the mechanisms whereby a number of cytoplasmic and nuclear signaling events may be integrated.

Dickkopf 1 mediates glucocorticoid-induced changes in human neural progenitor cell proliferation and differentiation

Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in their levels can induce neurotoxicity with detrimental consequences. Still, there is little information available on the effects of GC on human neural stem/progenitor cells (hNPC). In the present study, we have investigated the effects of the synthetic GC dexamethasone (Dex) on hNPC grown as neurospheres, with special focus on their proliferation and differentiation capacity and the underlying molecular mechanisms. Immunocytochemical stainings showed that Dex markedly decreases proliferation and neuronal differentiation while promoting glia cell formation. Analysis of pathway-specific genes revealed that Dex induces an upregulation of the Wnt-signaling antagonist DKK1. Moreover, Dex- or DKK1-treated hNPCs showed reduced transcriptional levels of the two canonical Wnt target genes cyclin D1 and inhibitor of DNA binding 2 (ID2). Chromatin immunoprecipitation showed that Dex, via the glucocorticoid receptor, interacts with the DKK1 promotor. Treatment of hNPC with recombinant DKK1 or neutralizing antibodies indicated that DKK1 has a critical role in the Dex-induced inhibition of proliferation and neuronal differentiation with a concomitant increase in glial cells. Taken together, our findings show that GC reduce proliferation and interfere with differentiation of hNPCs via the canonical Wnt-signaling pathway.

Blockade of the NFκB pathway drives differentiating glioblastoma-initiating cells into senescence both in vitro and in vivo

Glioblastoma multiforme is one of the most devastating cancers and presents unique challenges to therapy because of its aggressive behavior. Cancer-initiating or progenitor cells have been described to be the only cell population with tumorigenic capacity in glioblastoma. Therefore, effective therapeutic strategies targeting these cells or the early precursors may be beneficial. We have established different cultures of glioblastoma-initiating cells (GICs) derived from surgical specimens and found that, after induction of differentiation, the NFκB transcriptional pathway was activated, as determined by analyzing key proteins such as p65 and IκB and the upregulation of a number of target genes. We also showed that blockade of nuclear factor (NF)κB signaling in differentiating GICs by different genetic strategies or treatment with small-molecule inhibitors, promoted replication arrest and senescence. This effect was partly mediated by reduced levels of the NFκB target gene cyclin D1, because its downregulation by RNA interference reproduced a similar phenotype. Furthermore, these results were confirmed in a xenograft model. Intravenous treatment of immunodeficient mice bearing human GIC-derived tumors with a novel small-molecule inhibitor of the NFκB pathway induced senescence of tumor cells but no ultrastructural alterations of the brain parenchyma were detected. These findings reveal that activation of NFκB may keep differentiating GICs from acquiring a mature postmitotic phenotype, thus allowing cell proliferation, and support the rationale for therapeutic strategies aimed to promote premature senescence of differentiating GICs by blocking key factors within the NFκB pathway.

Responses of glial cells to stress and glucocorticoids

A growing body of evidence suggests that glial cells are involved in practically all aspects of neural function. Glial cells regulate the homeostasis of the brain, influence the development of the nervous system, modulate synaptic activity, and carry out the immune response inside the brain. In addition, they play an important role in the restoration of the nervous system after damage, and they also participate in various neurodegenerative disorders. In a similar way, the importance of stress and glucocorticoids (GCs) on brain function is being increasingly recognized. Within the brain, stress hormones target both neurons and glial cells. Through their actions on these cells, glucocorticoids exert organizational functions on various processes of the developing brain and contribute to neuronal plasticity in the adult brain. Moreover, stress and glucocorticoids have become especially attractive in the study of a number of neurodegenerative disorders. However, studies on the mechanisms behind glucocorticoid-induced regulation of brain function have been classically focused on their effects on neurons. In this review, we start by describing the main functions of glial cells and then proceed to present data highlighting the effects of stress and GCs on brain function. We conclude the review by presenting recent evidence linking stress and glucocorticoids to glial cell function.

Initiation of dopaminergic differentiation of Nurr1(-) mesencephalic precursor cells depends on activation of multiple mitogen-activated protein kinase pathways

Interleukin-1 (IL-1) plays a pivotal role in terminal dopaminergic differentiation of midbrain-derived neural precursor cells already committed to the mesencephalic dopaminergic phenotype (named mdNPCs for mesencephalic dopaminergic neural precursor cells). Here we characterized the molecular events in long-term expanded rat nuclear receptor related-1(-) (Nurr1(-)) mdNPCs in response to IL-1beta during their terminal dopaminergic specification. We showed that IL-1beta induced a rapid induction of mRNA of dopaminergic key fate-determining transcription factors, such as Nurr1 and Pitx3, and a subsequent increase of tyrosine hydroxylase protein as an early marker for dopaminergic neurons in vitro. These effects of IL-1beta were specific for mdNPCs and were not observed in striatal neural precursor cells (NPCs). Surprisingly, IL-1beta did not activate the NF-kappaB pathway or the transcription factor activating protein 1 (AP-1), but inhibition of nuclear translocation of NF-kappaB by SN50 facilitated IL-1beta-induced Nurr1 expression and dopaminergic differentiation of mdNPCs. Incubation of mdNPCs with IL-1beta led to a rapid phosphorylation of ERK1/2 and p38 mitogen-activated protein (MAP) kinases within 1 to 3 hours, whereas Jun kinase was not phosphorylated in response to IL-1beta. Consistently, inhibition of the ERK1/2 pathway or p38 MAP kinase blocked Nurr1 upregulation and further dopaminergic specification of mdNPCs, but not differentiation into MAP2ab(+) neurons. IL-1 receptor antagonist did not block early dopaminergic differentiation events, suggesting that the effects of IL-1beta are not mediated through activation of IL-1 receptor type I. Our results indicate that induction of terminal dopaminergic specification of Nurr1(-) mdNPCs by IL-1beta depends on activation of the ERK1/2 and p38 MAP kinase pathway.

Adult cerebrospinal fluid inhibits neurogenesis but facilitates gliogenesis from fetal rat neural stem cells

Neural stem cells (NSCs) are a promising source for cell replacement therapies for neurological diseases. Administration of NSCs into the cerebrospinal fluid (CSF) offers a nontraumatic transplantation method into the brain. However, cell survival and intraparenchymal migration of the transplants are limited. Furthermore, CSF was recently reported to be an important milieu for controlling stem cell processes in the brain. We studied the effects of adult human leptomeningeal CSF on the behavior of fetal rat NSCs. CSF increased survival of NSCs compared with standard culture media during stem cell maintenance and differentiation. The presence of CSF enhanced NSC differentiation, leading to a faster loss of self-renewal capacity and faster and stronger neurite outgrowth. Some of these effects (mainly cell survival, neurite brancing) were blocked by addition of the bone morphogenic protein (BMP) inhibitor noggin. After differentiation in CSF, significantly fewer MAP2ab(+) neurons were found, but there were more GFAP(+) astroglia compared with standard media. By RT-PCR analysis, we determined a decrease of mRNA of the NSC marker gene Nestin but an increase of Gfap mRNA during differentiation up to 72 hr in CSF compared with standard media. Our data demonstrate that adult human leptomeningeal CSF enhances cell survival of fetal rat NSCs during proliferation and differentiation. Furthermore, CSF provides a stimulus for gliogenesis but inhibits neurogenesis from fetal NSCs. Our data suggest that CSF contains factors such as BMPs regulating NSC behavior, and we hypothesize that fast differentiation of NSCs in CSF leads to a rapid loss of migration capacity of intrathecally transplanted NSCs.

No short-term benefits of antenatal corticosteroid treatment in severely preterm growth restricted fetuses: a case-control study

BACKGROUND

Antenatal corticosteroid administration to premature, growth restricted fetuses may not be beneficial and even have adverse effects on neonatal outcome.

AIMS

To determine if preterm growth restricted fetuses benefit from antenatal corticosteroids.

STUDY DESIGN

Retrospective cohort study.

METHODS

All singleton pregnancies with growth restricted fetuses delivered at our department before 34 weeks' gestation or weighing less than 1500 g, between January 2001 and December 2005, were retrospectively reviewed. Neonatal outcome was compared between growth restricted fetuses (defined as abnormal flow patterns in umbilical and middle cerebral arteries) that received antenatal CST (CST group) and those who did not receive antenatal CST (no CST group). The administration of CST appeared to be quasi randomized.

RESULTS

A total of 88 pregnancies fulfilled the inclusion criteria (CST group, n=54; no CST group, n=34). The incidence of neonatal respiratory distress syndrome in the CST and no CST group was 42% (22/54) and 50% (17/34), respectively (p=0.44). Neonatal mortality in the CST and no CST group was 9% (5/54) and 12% (4/34), respectively (p=0.73). The prevalence of adverse neonatal outcome (neonatal mortality, major neonatal morbidity or severe cerebral lesions) in the CST and no CST group was 28% (15/54) versus 24% (8/34), (p=0.62).

CONCLUSIONS

Administration of CST to growth restricted preterm fetuses does not appear to be beneficial with respect to short term neonatal outcome.

Correlation of circulating CD133+ progenitor subclasses with a mild phenotype in Duchenne muscular dystrophy patients

Background

Various prognostic serum and cellular markers have been identified for many diseases, such as cardiovascular diseases and tumor pathologies. Here we assessed whether the levels of certain stem cells may predict the progression of Duchenne muscular dystrophy (DMD).

Methods and Findings

The levels of several subpopulations of circulating stem cells expressing the CD133 antigen were determined by flow cytometry in 70 DMD patients. The correlation between the levels and clinical status was assessed by statistical analysis. The median (±SD) age of the population was 10.66±3.81 (range 3 to 20 years). The levels of CD133+CXCR4+CD34- stem cells were significantly higher in DMD patients compared to healthy controls (mean±standard deviation: 17.38±1.38 vs. 11.0±1.70; P = 0.03) with a tendency towards decreased levels in older patients. Moreover, the levels of this subpopulation of cells correlated with the clinical condition. In a subgroup of 19 DMD patients after 24 months of follow-up, increased levels of CD133+CXCR4+CD34- cells was shown to be associated with a phenotype characterised by slower disease progression. The circulating CD133+CXCR4+CD34- cells in patients from different ages did not exhibit significant differences in their myogenic and endothelial in vitro differentiation capacity.

Conclusions

Our results suggest that levels of CD133+CXCR4+CD34- could function as a new prognostic clinical marker for the progression of DMD.

Stage-dependent vulnerability of fetal mesencephalic neuroprogenitors towards dopaminergic neurotoxins

Although extensive knowledge exists on selective vulnerability of dopaminergic neurons against parkinsonism-inducing neurotoxins, there is a complete lack of such data on immature neuroprogenitors. Here we investigated the toxicity of 1-methyl-4-phenylpyridinium (MPP+), 6-hydroxydopamine (6-OHDA) and the free radical generator H2O2 on various developmental stages of predopaminergic mesencephalic neuroprogenitors (mNPCs) to evaluate stage-dependency of selective dopaminergic neurotoxicity. Striatal NPCs (sNPCs) without dopaminergic differentiation potential served as controls. Exposure of both undifferentiated NPCs to MPP+ resulted in concentration-dependent cell death at concentrations of >10 microM after 72 h without differences between both cell types, while 6-OHDA led to relevant cell death at 1000 microM after 24h with significant higher sensitivity of mNPCs compared to sNPCs. H2O2 did not induce relevant cell death in all cell types. In NPC cultures differentiated for 14 days, MPP+ showed enhanced toxicity compared to the undifferentiated counterparts, but no significant differences between both NPC type and differentiation conditions. 6-OHDA showed similar toxicity pattern in differentiated compared to undifferentiated NPCs. By evaluating the toxicity of MPP+ on MAP2ab+ neurons derived from both mNPCs and sNPCs as well as tyrosine hydroxylase (TH)+ dopaminergic cells from mNPCs, we found concentration-dependent cell death of all cell types with no increased vulnerability of TH+ cells. Primary TH+ neurons showed significantly higher vulnerability to MPP+. Together, we demonstrated stage-dependent vulnerability of NPCs towards dopaminergic neurotoxins, but no selective vulnerability of NPC-derived TH+ dopaminergic cells towards MPP+. This cell system seems not suitable as a screening tool for selective dopaminergic toxicity.