Grafted Human Embryonic Progenitors Expressing Neurogenin-2 Stimulate Axonal Sprouting and Improve Motor Recovery after Severe Spinal Cord Injury

7 p.Background: Spinal cord injury (SCI) is a widely spread pathology with currently no effective treatment for any symptom. Regenerative medicine through cell transplantation is a very attractive strategy and may be used in different non-exclusive ways to promote functional recovery. We investigated functional and structural outcomes after grafting human embryonic neural progenitors (hENPs) in spinal cord-lesioned rats.Methods and Principal Findings: With the objective of translation to clinics we have chosen a paradigm of delayed grafting, i.e., one week after lesion, in a severe model of spinal cord compression in adult rats. hENPs were either naive or engineered to express Neurogenin 2 (Ngn2). Moreover, we have compared integrating and non-integrating lentiviral vectors, since the latter present reduced risks of insertional mutagenesis. We show that transplantation of hENPs transduced to express Ngn2 fully restore weight support and improve functional motor recovery after severe spinal cord compression at thoracic level. This was correlated with partial restoration of serotonin innervations at lumbar level, and translocation of 5HT1A receptors to the plasma membrane of motoneurons. Since hENPs were not detectable 4 weeks after grafting, transitory expression of Ngn2 appears sufficient to achieve motor recovery and to permit axonal regeneration. Importantly, we also demonstrate that transplantation of naive hENPs is detrimental to functional recovery.Conclusions and Significance: Transplantation and short-term survival of Ngn2-expressing hENPs restore weight support after SCI and partially restore serotonin fibers density and 5HT1A receptor pattern caudal to the lesion. Moreover, grafting of naive-hENPs was found to worsen the outcome versus injured only animals, thus pointing to the possible detrimental effect of stem cell-based therapy per se in SCI. This is of major importance given the increasing number of clinical trials involving cell grafting developed for SCI patients.This study was supported by the European Union FP6 "RESCUE" STREP; the "Institut pour la Recherche sur la Moelle Epiniere"; the "Academie de Medecine"; the "Societe Francaise de Neurochirurgie"; "Verticale" and the "Association Demain Debout Aquitaine". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Non integrative lentiviral vactors for gene transfer in the retina

Purpose:Lentiviral vectors are among the most efficient gene transfer tools for both dividing and non dividing cells, including pigmented epithelial cells of the retina. One of the latest developments in the field, which represents a significant advance in biosafety, consists in the use of non integrative lentiviral vectors (NILVs). These newly described tools were already shown to be efficient in various tissues, such as the retina. They allow prolonged transgene expression as long as the transduced cells do not divide or divide slowly. However, they were also shown to induce transgene expression less efficiently than their integrative counterparts. Further investigations are thus needed to improve their potential. To this aim, different strategies are under evaluation. In this study, we focused on using different integrase mutations. Methods:We considered different integrase mutations, including modifications in the catalytic site and in the C-terminal domain of the enzyme. Lentiviral vectors bearing these mutant integrases and allowing expression of various transgenes were produced and characterized in vitro and in vivo. In particular, we evaluated their transgene expression capability. Influence of integrase mutation on the residual integration activity was also investigated. Results:In line with the fact that the lentiviral integrase is involved in several steps of the replication cycle of lentiviruses, we observed that integrase mutations can modify lentiviral vector features, resulting in different transduction efficiencies as well as modulation of the integration activity. Conclusions:NILVs appear as suitable tools for gene transfer in the retina, particularly to transduce RPE cells. They can be advantageously used, for instance, to develop neuroprotective strategies aimed at rescuing photoreceptors from death in various retinal diseases

Increased dopamine after mating impairs olfaction and prevents odor interference with pregnancy.

In rodents, social odor sensing influences female reproductive status by affecting neuroendocrine cascades. The odor of male mouse urine can induce ovulation or block pregnancy within 3 d post coitus. Females avoid the action of such olfactory stimuli after embryonic implantation. The mechanisms underlying these changes are unknown. Here we report that shortly after mating, a surge in dopamine in the mouse main olfactory bulb impairs the perception of social odors contained in male urine. Treatment of females at 6.5 d post coitus with a dopamine D2 receptor antagonist restores social odor sensing and favors disruption of pregnancy by inhibition of prolactin release, when administered in the presence of alien male urine odors. These results show that an active sensory barrier blocks social olfactory cues detrimental to pregnancy, consistent with the main olfactory bulb being a major relay through which social odor modulates reproductive status

Increased dopamine after mating impairs olfaction and prevents odor interference with pregnancy.

In rodents, social odor sensing influences female reproductive status by affecting neuroendocrine cascades. The odor of male mouse urine can induce ovulation or block pregnancy within 3 d post coitus. Females avoid the action of such olfactory stimuli after embryonic implantation. The mechanisms underlying these changes are unknown. Here we report that shortly after mating, a surge in dopamine in the mouse main olfactory bulb impairs the perception of social odors contained in male urine. Treatment of females at 6.5 d post coitus with a dopamine D2 receptor antagonist restores social odor sensing and favors disruption of pregnancy by inhibition of prolactin release, when administered in the presence of alien male urine odors. These results show that an active sensory barrier blocks social olfactory cues detrimental to pregnancy, consistent with the main olfactory bulb being a major relay through which social odor modulates reproductive status

Increased interleukin-6 correlates with myelin oligodendrocyte glycoprotein antibodies in pediatric monophasic demyelinating diseases and multiple sclerosis.

Acquired demyelinating syndromes (ADS) in children evolve either as a monophasic disease diagnosed as acute demyelinating encephalomyelitis (ADEM), transverse myelitis (TM) or optic neuritis (ON), or a multiphasic one with several relapses most often leading to the diagnosis of multiple sclerosis (MS) or neuromyelitis optica (NMO). These neuroinflammatory disorders are increasingly associated with autoantibodies against proteins such as aquaporin-4 in rare instances, and more frequently against myelin oligodendrocyte glycoprotein (MOG). Recently, in adult NMO patients, C5a levels were shown to be elevated in cerebrospinal fluid (CSF) during acute exacerbation. We investigated the CSF levels of anaphylatoxins and pro-inflammatory cytokines, and plasma MOG antibodies in onset samples from children with ADS. Thirty four children presenting with a first episode of ADS, 17 with monophasic ADS (9 with ADEM, 4 with TM and 4 with ON) and 17 with MS, who had paired blood and CSF samples at onset were included and compared to 12 patients with other non-inflammatory neurological disorders (OND). Cytokines and anaphylatoxins in CSF were measured by Cytometric Bead Array immunoassay. MOG antibody titers in plasma were tested by flow cytometry using a stable cell line expressing full-length human MOG. We found a significant increase in C5a levels in the CSF of patients with monophasic ADS (n=17) compared to OND (n=12, p=0.0036) and to MS (n=17, p=0.0371). The C5a levels in MS were higher than in OND without reaching significance (p=0.2). CSF IL-6 levels were significantly increased in monophasic ADS compared to OND (p=0.0027) and to MS (p=0.0046). MOG antibody plasma levels were significantly higher in monophasic ADS (p<0.0001) and, to a lesser extent, in MS compared to OND (p=0.0023). Plasma MOG antibodies and CSF IL-6 levels were significantly correlated (r=0.51, p=0.018). CSF C5a and IL-6 levels are increased in monophasic ADS but not in MS when compared to OND, suggesting that these markers may help to predict monophasic or relapsing fate of ADS at onset. MOG antibody titers, which were higher in monophasic ADS than in MS, correlated with IL-6 levels, but not with C5a, suggesting an association between MOG antibodies and neuroinflammation in pediatric ADS

Improvement of preclinical animal models for autoimmune-mediated disorders via reverse translation of failed therapies

The poor translational validity of autoimmune-mediated inflammatory disease (AIMID) models in inbred and specific pathogen-free (SPF) rodents underlies the high attrition of new treatments for the corresponding human disease. Experimental autoimmune encephalomyelitis (EAE) is a frequently used preclinical AIMID model. We discuss here how crucial information needed for the innovation of current preclinical models can be obtained from postclinical analysis of the nonhuman primate EAE model, highlighting the mechanistic reasons why some therapies fail and others succeed. These new insights can also help identify new targets for treatment

A macaque model of rheumatoid arthritis by immunization with citrullinated peptides: lessons for the human disease

Background Recent evolution in the understanding of rheumatoid arthritis (RA) mechanisms is the role of antibodies directed against citrullinated (cit) proteins (ACPAs). The shared epitope (SE) on the MHC class II is the main genetic risk factor of RA and favors presence of ACPAs. Mouse models dependent on cit peptides immunization require transgenic expression of the SE and are controversial. Non-human primates are ideal to study the interaction between ACPA and RA since 8% carry, similarly to humans, the SE called the H6 haplotype.Objectives The goal of this study was to develop a new animal model of RA based on immunization of genetically predisposed macaques against cit peptides to generate an ACPA-mediated model of arthritis.Methods Six macaques were intra dermally (ID) immunized with 4 peptides: vimentin (59–71) and (66–78), α fibrinogen (79–91) and aggrecan (89–103). H6 animals were immunized with either cit (n=2) or arginine (arg) (n=2) containing peptides. Two non H6 animals were immunized with cit peptides. These peptides are known to induce a T cell response in RA patients carrying the SE. T-cell response was assessed with Interferon γ ELISPOT and B-cell response by ELISA. An intra articular (IA) boost was done 30 weeks after initial immunization with either incomplete Freud's adjuvant (IFA) alone, IFA and cit peptides and IFA plus non relevant peptides.Results In the macaques, the T-cell response was specific to cit or arg peptides (depending on the peptides used for immunization). Surprisingly, the presence of the H6 epitope did not influence the response. Conversely the antibodies generated in response to the peptides were cross-reactive between the cit and arg peptides. Since no clinical response was observed, an IA boost was performed with the same 4 cit peptides and IFA adjuvant. This led to a prolonged neutrophil-rich mono-arthritis preferentially in H6 animals (Figure). Conversely, animals boosted with IFA alone only or with IFA plus myelin oligodendrocyte glycoprotein (MOG) peptides and previously immunized with MOG peptides presented with a transient mono-arthritis. Histological analysis revealed a local mononuclear infiltrate in one of the two animals that had prolonged knee monoarthritis. There was no clinical polyarthritis but 2 animals displayed synovial proliferation in 1 MCP and 1 MTP, respectively

Improvement of preclinical animal models for autoimmune-mediated disorders via reverse translation of failed therapies

The poor translational validity of autoimmune-mediated inflammatory disease (AIMID) models in inbred and specific pathogen-free (SPF) rodents underlies the high attrition of new treatments for the corresponding human disease. Experimental autoimmune encephalomyelitis (EAE) is a frequently used preclinical AIMID model. We discuss here how crucial information needed for the innovation of current preclinical models can be obtained from postclinical analysis of the nonhuman primate EAE model, highlighting the mechanistic reasons why some therapies fail and others succeed. These new insights can also help identify new targets for treatment