Expression of placental CD146 is dysregulated by prenatal alcohol exposure and contributes in cortical vasculature development and positioning of vessel-associated oligodendrocytes

Recent data showed that prenatal alcohol exposure (PAE) impairs the "placenta-brain" axis controlling fetal brain angiogenesis in human and preclinical models. Placental growth factor (PlGF) has been identified as a proangiogenic messenger between these two organs. CD146, a partner of the VEGFR-1/2 signalosome, is involved in placental angiogenesis and exists as a soluble circulating form. The aim of the present study was to investigate whether placental CD146 may contribute to brain vascular defects described in fetal alcohol spectrum disorder. At a physiological level, quantitative reverse transcription polymerase chain reaction experiments performed in human placenta showed that CD146 is expressed in developing villi and that membrane and soluble forms of CD146 are differentially expressed from the first trimester to term. In the mouse placenta, a similar expression pattern of CD146 was found. CD146 immunoreactivity was detected in the labyrinth zone and colocalized with CD31-positive endothelial cells. Significant amounts of soluble CD146 were quantified by ELISA in fetal blood, and the levels decreased after birth. In the fetal brain, the membrane form of CD146 was the majority and colocalized with microvessels. At a pathophysiological level, PAE induced marked dysregulation of CD146 expression. The soluble form of CD146 decreased in both placenta and fetal blood, whereas it increased in the fetal brain. Similarly, the expression of several members of the CD146 signalosome, such as VEGFR2 and PSEN, was differentially impaired between the two organs by PAE. At a functional level, targeted repression of placental CD146 by in utero electroporation (IUE) of CRISPR/Cas9 lentiviral plasmids resulted in (i) a decrease in cortical vessel density, (ii) a loss of radial vascular organization, and (iii) a reduced density of oligodendrocytes. Statistical analysis showed that the more the vasculature was impaired, the more the cortical oligodendrocyte density was reduced. Altogether, these data support that placental CD146 contributes to the proangiogenic "placenta-brain" axis and that placental CD146 dysfunction contributes to the cortical oligo-vascular development. Soluble CD146 would represent a promising placental biomarker candidate representative of alcohol-induced neurovascular defects in neonates, as recently suggested by PlGF (patents WO2016207253 and WO2018100143).

Global sphingosine-1-phosphate receptor 2 deficiency attenuates neuroinflammation and ischemic-reperfusion injury after neonatal stroke

Arterial ischemic stroke is common in neonates-1 per 2,300-5,000 births-and therapeutic targets remain insufficiently defined. Sphingosine-1-phosphate receptor 2 (S1PR2), a major regulator of the CNS and immune systems, is injurious in adult stroke. Here, we assessed whether S1PR2 contributes to stroke induced by 3 h transient middle cerebral artery occlusion (tMCAO) in S1PR2 heterozygous (HET), knockout (KO), and wild type (WT) postnatal day 9 pups. HET and WT of both sexes displayed functional deficits in Open Field test whereas injured KO at 24 h reperfusion performed similarly to naives. S1PR2 deficiency protected neurons, attenuated infiltration of inflammatory monocytes, and altered vessel-microglia interactions without reducing increased cytokine levels in injured regions at 72 h. Pharmacologic inhibition of S1PR2 after tMCAO by JTE-013 attenuated injury 72 h after tMCAO. Importantly, the lack of S1PR2 alleviated anxiety and brain atrophy during chronic injury. Altogether, we identify S1PR2 as a potential new target for mitigating neonatal stroke.

Mesenchymal Stem Cell (MSC)-Derived Extracellular Vesicles Protect from Neonatal Stroke by Interacting with Microglial Cells

Mesenchymal stem cell (MSC)-based therapies are beneficial in models of perinatal stroke and hypoxia-ischemia. Mounting evidence suggests that in adult injury models, including stroke, MSC-derived small extracellular vesicles (MSC-sEV) contribute to the neuroprotective and regenerative effects of MSCs. Herein, we examined if MSC-sEV protect neonatal brain from stroke and if this effect is mediated via communication with microglia. MSC-sEV derived from bone marrow MSCs were characterized by size distribution (NanoSight™) and identity (protein markers). Studies in microglial cells isolated from the injured or contralateral cortex of postnatal day 9 (P9) mice subjected to a 3-h middle cerebral artery occlusion (tMCAO) and cultured (in vitro) revealed that uptake of fluorescently labeled MSC-sEV was significantly greater by microglia from the injured cortex vs. contralateral cortex. The cell-type-specific spatiotemporal distribution of MSC-sEV was also determined in vivo after tMCAO at P9. MSC-sEV administered at reperfusion, either by intracerebroventricular (ICV) or by intranasal (IN) routes, accumulated in the hemisphere ipsilateral to the occlusion, with differing spatial distribution 2 h, 18 h, and 72 h regardless of the administration route. By 72 h, MSC-sEV in the IN group was predominantly observed in Iba1+ cells with retracted processes and in GLUT1+ blood vessels in ischemic-reperfused regions. MSC-sEV presence in Iba1+ cells was sustained. MSC-sEV administration also significantly reduced injury volume 72 h after tMCAO in part via modulatory effects on microglial cells. Together, these data establish feasibility for MSC-sEV delivery to injured neonatal brain via a clinically relevant IN route, which affords protection during sub-acute injury phase.

Neonatal stroke enhances interaction of microglia-derived extracellular vesicles with microglial cells

Microglial cells support brain homeostasis under physiological conditions and modulate brain injury in a context-dependent and brain maturation-dependent manner. Microglial cells protect neonatal brain from acute stroke. While microglial signaling via direct cell-cell interaction and release of variety of molecules is intensely studied, less is known about microglial signaling via release and uptake of extracellular vesicles (EVs). We asked whether neonatal stroke alters release of microglial EVs (MEV) and MEV communication with activated microglia. We pulled down and plated microglia from ischemic-reperfused and contralateral cortex 24 h after transient middle cerebral artery occlusion (tMCAO) in postnatal day 9 mice, isolated and characterized microglia-derived microvesicles (P3-MEV) and exosomes (P4-MEV), and determined uptake of fluorescently labeled P3-MEV and P4-MEV by plated microglia derived from ischemic-reperfused and contralateral cortex. We then examined how reducing EVs release in neonatal brain-by intra-cortical injection of CRISPR-Cas9-Smpd3/KO (Smpd3/KD) to downregulate Smpd3 gene to disrupt neutral sphingomyelinase-2 (N-SMase2)-impacts P3-MEV and P4-MEV release and stroke injury. Both size and protein composition differed between P3-MEV and P4-MEV. tMCAO further altered protein composition of P3-MEV and P4-MEV and significantly, up to 5-fold, increased uptake of both vesicle subtypes by microglia from ischemic-reperfused regions. Under physiological conditions neurons were the predominant cell type expressing N-SMase-2, an enzyme involved in lipid signaling and EVs release. After tMCAO N-SMase-2 expression was diminished in injured neurons but increased in activated microglia/macrophages, leading to overall reduced N-SMase-2 activity. Compared to intracerebral injection of control plasmid, CRISPR-Cas9-Smpd3/Ct, Smpd3/KD injection further reduced N-SMase-2 activity and significantly reduced injury. Smpd3 downregulation decreased MEV release from injured regions, reduced Smpd3/KD-P3-MEV uptake and abolished Smpd3/KD-P4-MEV uptake by microglia from ischemic-reperfused region. Cumulatively, these data demonstrate that microglial cells release both microvesicles and exosomes in naïve neonatal brain, that the state of microglial activation determines both properties of released EVs and their recognition/uptake by microglia in ischemic-reperfused and control regions, suggesting a modulatory role of MEV in neonatal stroke, and that sphingosine/N-SMase-2 signaling contributes both to EVs release and uptake (predominantly P4-MEV) after neonatal stroke.

Abstract TP103: Neonatal Stroke Alters Communication of Microglial Cells With Microglia-Derived Exosomes and Microvesicles

Inflammation modulates brain injury after perinatal arterial stroke. We previously demonstrated that microglial cells play an important role in protecting neonatal brain from acute stroke by phagocytosing dying neurons, attenuating cytokine accumulation and by protecting neurovascular integrity. Microglia may modulate injury in neonatal stroke via crosstalk between cells via other mechanisms, such as by releasing extracellular vesicles from microglia (MEV), including exosomes (MExo) and microvesicles (MMV).

Aim: Elucidate the mechanisms of MEV communication with brain cells in injured neonatal brain and role of these vesicles in protection.

Methods: Transient middle cerebral artery occlusion (tMCAO) was performed in postnatal day 9 (P9). Microglial cells were isolated by CD11b-conjugated beads from ischemic and contralateral cortex 24h after reperfusion and plated at same density for 96h. MEV were isolated by multi-step centrifugation (MMV) and ultra-centrifugation (MExo) and labeled with MiniClaret dye. Uptake of MEV from contralateral/ injured cortex by Iba1 + -cells from contralateral and injured regions was determined 10, 30 & 120min. Images co-stained with flotillin-1, which is strongly expressed in MMV but not in MExo, were analyzed using Volocity ® .

Results: The uptake of MEV from injured cortex by microglia from injured cortex was significantly higher than uptake of contralateral-MEV by microglia from uninjured cortex (5-fold at 10min; p<0.0001) regardless of time. Uptake of MEV from injured regions by microglia from contralateral cortex and contralateral-MEV by microglia from injured cortex were low. While the number of ipsilateral and contralateral flotillin-1 + -MMV was similar, uptake of flotillin-1 - -MExo and ratio of ipsilateral MExo/MEV were significantly increase.

Summary: Our data demonstrate selective enhancement of microglial communication with MEV from activated microglia after acute neonatal stroke as well as distinct MEV-subtype-dependent mechanisms of communication in injured brain. This mechanism could provide a better understanding of the role of microglia on the severity of neonatal stroke.

Support: AHA17IRG33430004, RO1NS44025, RO1HL139685

[Fetal alcohol exposure: when placenta would help to the early diagnosis of child brain impairments]

Alcohol consumption during pregnancy constitutes a major cause of neurodevelopmental and behavioral disabilities. Whereas it is possible for clinicians to establish a perinatal diagnosis of fetal alcohol syndrome, the more severe expression of fetal alcohol spectrum disorder (FASD), most FASD children are late or mis-diagnosed due to a lack of clear morphological and neurodevelopmental abnormalities. Several precious years of care are consequently lost. Recent data revealed a functional placenta-brain axis involved in the control of the fetal brain angiogenesis which is impaired by in utero alcohol exposure. Because in the developing fetal brain a correct angiogenesis is required for a correct neurodevelopment, these preclinical and clinical advances pave the way for a new generation of placental biomarkers for early diagnosis of FASD.

A de novo variant in ADGRL2 suggests a novel mechanism underlying the previously undescribed association of extreme microcephaly with severely reduced sulcation and rhombencephalosynapsis

Extreme microcephaly and rhombencephalosynapsis represent unusual pathological conditions, each of which occurs in isolation or in association with various other cerebral and or extracerebral anomalies. Unlike microcephaly for which several disease-causing genes have been identified with different modes of inheritance, the molecular bases of rhombencephalosynapsis remain unknown and rhombencephalosynapsis presents mainly as a sporadic condition consistent with de novo dominant variations. We report for the first time the association of extreme microcephaly with almost no sulcation and rhombencephalosynapsis in a fœtus for which comparative patient-parent exome sequencing strategy revealed a heterozygous de novo missense variant in the ADGRL2 gene. ADGRL2 encodes latrophilin 2, an adhesion G-protein-coupled receptor whose exogenous ligand is α-latrotoxin. Adgrl2 immunohistochemistry and in situ hybridization revealed expression in the telencephalon, mesencephalon and rhombencephalon of mouse and chicken embryos. In human brain embryos and fœtuses, Adgrl2 immunoreactivity was observed in the hemispheric and cerebellar germinal zones, the cortical plate, basal ganglia, pons and cerebellar cortex. Microfluorimetry experiments evaluating intracellular calcium release in response to α-latrotoxin binding showed significantly reduced cytosolic calcium release in the fœtus amniocytes vs amniocytes from age-matched control fœtuses and in HeLa cells transfected with mutant ADGRL2 cDNA vs wild-type construct. Embryonic lethality was also observed in constitutive Adgrl2^−/− mice. In Adgrl2^+/− mice, MRI studies revealed microcephaly and vermis hypoplasia. Cell adhesion and wound healing assays demonstrated that the variation increased cell adhesion properties and reduced cell motility. Furthermore, HeLa cells overexpressing mutant ADGRL2 displayed a highly developed cytoplasmic F-actin network related to cytoskeletal dynamic modulation. ADGRL2 is the first gene identified as being responsible for extreme microcephaly with rhombencephalosynapsis. Increased cell adhesion, reduced cell motility and cytoskeletal dynamic alterations induced by the variant therefore represent a new mechanism responsible for microcephaly.

Magnesium Sulfate Prevents Neurochemical and Long-Term Behavioral Consequences of Neonatal Excitotoxic Lesions: Comparison Between Male and Female Mice

Magnesium sulfate (MgSO4) administration to mothers at risk of preterm delivery is proposed as a neuroprotective strategy against neurological alterations such as cerebral palsy in newborns. However, long-term beneficial or adverse effects of MgSO4 and sex-specific sensitivity remain to be investigated. We conducted behavioral and neurochemical studies of MgSO4 effects in males and females, from the perinatal period to adolescence in a mouse model of cerebral neonatal lesion. The lesion was produced in 5-day-old (P5) pups by ibotenate intracortical injection. MgSO4 (600 mg/kg, i.p.) prior to ibotenate prevented lesion-induced sensorimotor alterations in both sexes at P6 and P7. The lesion increased glutamate level at P10 in the prefrontal cortex, which was prevented by MgSO4 in males. In neonatally lesioned adolescent mice, males exhibited more sequelae than females in motor and cognitive functions. In the perirhinal cortex of adolescent mice, the neonatal lesion induced an increase in vesicular glutamate transporter 1 density in males only, which was negatively correlated with cognitive scores. Long-term sequelae were prevented by neonatal MgSO4 administration. MgSO4 never induced short- or long-term deleterious effect on its own. These results also strongly suggest that sex-specific neuroprotection should be foreseen in preterm infants.

Experimental and clinical evidence of differential effects of magnesium sulfate on neuroprotection and angiogenesis in the fetal brain

Clinical studies showed beneficial effects of magnesium sulfate regarding the risk of cerebral palsy. However, regimen protocols fluctuate worldwide and risks of adverse effects impacting the vascular system have been reported for human neonates, keeping open the question of the optimal dosing. Using clinically relevant concentrations and doses of magnesium sulfate, experiments consisted of characterizing, respectively, ex vivo and in vivo, the effects of magnesium sulfate on the nervous and vascular systems of mouse neonates by targeting neuroprotection, angiogenesis, and hemodynamic factors and in measuring, in human fetuses, the impact of a 4‐g neuroprotective loading dose of magnesium sulfate on brain hemodynamic parameters. Preclinical experiments using cultured cortical slices from mouse neonates showed that the lowest and highest tested concentrations of magnesium sulfate were equally potent to prevent excitotoxic‐induced cell death, cell edema, cell burst, and intracellular calcium increase, whereas no side effects were found regarding apoptosis. In contrast, in vivo data revealed that magnesium sulfate exerted dose‐dependent vascular effects on the fetal brain. In particular, it induced brain hypoperfusion, stabilization of Hif‐1α, long‐term upregulation of VEGF‐R2 expression, impaired endothelial viability, and altered cortical angiogenesis. Clinically, in contrast to 6‐g loading doses used in some protocols, a 4‐g bolus of magnesium sulfate did not altered fetal brain hemodynamic parameters. In conclusion, these data provide the first mechanistic evidence of double‐sword and dose‐dependent actions of magnesium sulfate on nervous and vascular systems. They strongly support the clinical use of neuroprotection protocols validated for the lowest (4‐g) loading dose of magnesium sulfate.

PLGF, a placental marker of fetal brain defects after in utero alcohol exposure

Most children with in utero alcohol exposure do not exhibit all features of fetal alcohol syndrome (FAS), and a challenge for clinicians is to make an early diagnosis of fetal alcohol spectrum disorders (FASD) to avoid lost opportunities for care. In brain, correct neurodevelopment requires proper angiogenesis. Since alcohol alters brain angiogenesis and the placenta is a major source of angiogenic factors, we hypothesized that it is involved in alcohol-induced brain vascular defects. In mouse, using in vivo repression and overexpression of PLGF, we investigated the contribution of placenta on fetal brain angiogenesis. In human, we performed a comparative molecular and morphological analysis of brain/placenta angiogenesis in alcohol-exposed fetuses. Results showed that prenatal alcohol exposure impairs placental angiogenesis, reduces PLGF levels and consequently alters fetal brain vasculature. Placental repression of PLGF altered brain VEGF-R1 expression and mimicked alcohol-induced vascular defects in the cortex. Over-expression of placental PGF rescued alcohol effects on fetal brain vessels. In human, alcohol exposure disrupted both placental and brain angiogenesis. PLGF expression was strongly decreased and angiogenesis defects observed in the fetal brain markedly correlated with placental vascular impairments. Placental PGF disruption impairs brain angiogenesis and likely predicts brain disabilities after in utero alcohol exposure. PLGF assay at birth could contribute to the early diagnosis of FASD.

Dysregulation of RasGRP1 in rheumatoid arthritis and modulation of RasGRP3 as a biomarker of TNFα inhibitors

Background

B and T cells play a key role in rheumatoid arthritis (RA) pathophysiology. RasGRP1 and RasGRP3 are involved in T and B cell receptors signaling, and belong to gene combination able to predict infliximab responsiveness, leading to the question of RasGRP1 and RasGRP3 involvement in RA.

Methods

RasGRP1 and RasGRP3 expression levels were measured by qRT-PCR and/or western-blot in peripheral blood mononuclear cells (PBMCs), in T and B cells from untreated RA patients and in RA patients treated by TNFα inhibitors. T and B cells from healthy controls (HC) were cultured with TNFα, and TNFα receptors neutralizing antibodies to highlight the TNFα effects on RasGRP1 and RasGRP3 pathways. MAPK pathways and apoptosis were respectively analyzed using the Proteome Profiler arrays and flow cytometry.

Results

In PBMCs from RA patients, gene expression levels of RasGRP1 were invariant while RasGRP3 was downregulated under TNFα inhibitors and upregulated under TNFα. In T cells from RA patients, RasGRP1 was decreased and its gene expression level was correlated with disease activity. In T cells from HC, TNFα stimulation increased RasGRP1 gene expression level while it reduced RasGRP1 protein expression level. Bryostatin-1 experiments have confirmed that the TNFα effect observed on T cells proliferation was due to the decrease of RasGRP1 expression. Besides, RasGRP3 expression level increased in PBMCs from RA patients under TNFα and in B cells from HC leading us to conclude that RasGRP3 in B cells was modulated by TNFα.

Conclusion

This study demonstrates RasGRP1 dysregulation in RA patients while RasGRP3 is characterized as a biomarker linked to TNFα inhibitors. After binding to TNFR1, TNFα reduced RasGRP1 protein expression resulting in inhibition of T cell activation.

Trial registration

Clinicaltrials.gov NCT00234234, registered 04 November 2008; NCT00767325, registered 05 October 2005.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0894-9) contains supplementary material, which is available to authorized users.

[HPV prophylactic vaccine coverage in France: Results of a survey among high school and university students in Marseilles' area]

OBJECTIVE

To assess HPV prophylactic vaccine coverage among French high school and university students as well as their level of education about this vaccine.

PATIENTS AND METHODS

An anonymous survey was conducted among 2500 high school and university students from the area of Marseilles, France, from December 2009 to April 2010.

RESULTS

A total of 2018 questionnaires were collected (80.7% participation rate). Mean age of participants was 20 years (range, 15-45 years). Only 671 (35.4%) participants reported having been vaccinated against HPV, of whom 510 (73.4%) had completed the three injections scheme. Practice of cytological cervical cancer screening was not significantly influenced by vaccination status. Thus, 578 (45.2%) participants who had not been vaccinated already had had a cervical cytology performed, versus 295 (43.3%) vaccinated ones (P=0.445). Among those not being vaccinated, 671 (49.8%) fulfilled criteria for a catch-up vaccination, of whom only 325 (48.4%) agreed for such a catch-up. Main reasons given for refusal for a catch-up vaccination were the lack of information about HPV vaccine and fear of side effects. In total, 1722 (90%) considered themselves as educated about the HPV vaccine. Source of education was attributed to doctors and media by 54.4% and 53.7% of participants, respectively. Educational role attributed to school and university was poor (3.4%).

CONCLUSION

Despite apparent satisfactory level of education, HPV prophylactic vaccine coverage among high school and university students appears to be insufficient.

Desloratadine 5 mg once daily improves the quality of life of patients with chronic idiopathic urticaria

BACKGROUND

Chronic urticaria is known to debilitate a person's quality of life via sleep disruption, itching lesions, fatigue, social isolation, energy loss and emotional/sexual difficulties. Once-daily desloratadine significantly improved the signs and symptoms of CIU.

OBJECTIVE

Assess the effect of desloratadine 5 mg once daily on the quality of life of patients suffering of chronic idiopathic urticaria (CIU). Study population One-hundred twenty-one consecutive patients with CIU present for at least 6 weeks prior to inclusion and with a current flare of at least 3 weeks, were included in the study in 24 Belgian centres.

RESULTS

The mean dermatology life quality index (DLQI) significantly decreased from baseline to day 7 and further to day 42. Sixty per cent and 77% of patients had a clinically significant change (i.e. a decrease of at least 2 points) at day 7 or day 42, respectively, as compared with that of day 0. Change in pruritus and size of the hives significantly correlated with the change in the score of the quality of life. One-third of patients experienced complete relief whereas in 1 of 10 patients no effect was experienced.

CONCLUSIONS

Desloratadine significantly improves the quality of life of patients with chronic idiopathic urticaria as reflected by the dermatology life quality index (DLQI).