Increased proliferation and neuronal fate in prairie vole brain progenitor cells cultured in vitro: effects by social exposure and sexual dimorphism.

BACKGROUND: The prairie vole (Microtus ochrogaster) is a socially monogamous rodent that establishes an enduring pair bond after cohabitation, with (6 h) or without (24 h) mating. Previously, we reported that social interaction and mating increased cell proliferation and differentiation to neuronal fate in neurogenic niches in male voles. We hypothesized that neurogenesis may be a neural plasticity mechanism involved in mating-induced pair bond formation. Here, we evaluated the differentiation potential of neural progenitor cells (NPCs) isolated from the subventricular zone (SVZ) of both female and male adult voles as a function of sociosexual experience. Animals were assigned to one of the following groups: (1) control (Co), sexually naive female and male voles that had no contact with another vole of the opposite sex; (2) social exposure (SE), males and females exposed to olfactory, auditory, and visual stimuli from a vole of the opposite sex, but without physical contact; and (3) social cohabitation with mating (SCM), male and female voles copulating to induce pair bonding formation. Subsequently, the NPCs were isolated from the SVZ, maintained, and supplemented with growth factors to form neurospheres in vitro. RESULTS: Notably, we detected in SE and SCM voles, a higher proliferation of neurosphere-derived Nestin + cells, as well as an increase in mature neurons (MAP2 +) and a decrease in glial (GFAP +) differentiated cells with some sex differences. These data suggest that when voles are exposed to sociosexual experiences that induce pair bonding, undifferentiated cells of the SVZ acquire a commitment to a neuronal lineage, and the determined potential of the neurosphere is conserved despite adaptations under in vitro conditions. Finally, we repeated the culture to obtain neurospheres under treatments with different hormones and factors (brain-derived neurotrophic factor, estradiol, prolactin, oxytocin, and progesterone); the ability of SVZ-isolated cells to generate neurospheres and differentiate in vitro into neurons or glial lineages in response to hormones or factors is also dependent on sex and sociosexual context. CONCLUSION: Social interactions that promote pair bonding in voles change the properties of cells isolated from the SVZ. Thus, SE or SCM induces a bias in the differentiation potential in both sexes, while SE is sufficient to promote proliferation in SVZ-isolated cells from male brains. In females, proliferation increases when mating is performed. The next question is whether the rise in proliferation and neurogenesis of cells from the SVZ are plastic processes essential for establishing, enhancing, maintaining, or accelerating pair bond formation. Highlights 1. Sociosexual experiences that promote pair bonding (social exposure and social cohabitation with mating) induce changes in the properties of neural stem/progenitor cells isolated from the SVZ in adult prairie voles. 2. Social interactions lead to increased proliferation and induce a bias in the differentiation potential of SVZ-isolated cells in both male and female voles. 3. The differentiation potential of SVZ-isolated cells is conserved under in vitro conditions, suggesting a commitment to a neuronal lineage under a sociosexual context. 4. Hormonal and growth factors treatments (brain-derived neurotrophic factor, estradiol, prolactin, oxytocin, and progesterone) affect the generation and differentiation of neurospheres, with dependencies on sex and sociosexual context. 5. Proliferation and neurogenesis in the SVZ may play a crucial role in establishing, enhancing, maintaining, or accelerating pair bond formation.

In this study, researchers evaluated whether social interactions and copulation induce changes in the proliferation and differentiation of neural progenitor cells in adult male and female voles using an in vitro neurosphere formation assay. The following groups were assigned: control animals without any exposure to another vole outside their litter, another group with social exposure consisting of sensory exposure to a vole of the opposite sex and a third group with social cohabitation and copulation. Forty eight hours after social interactions, cells were isolated from the neurogenic niche subventricular zone (SVZ) and cultured to assess their self-renewal and proliferation abilities to form neurospheres. The results showed in the social interaction groups, a greater number and growth of neurospheres in both males and females. Differentiation capacity was assessed by immunodetection of MAP2 and GFAP to identify neurons or glia, respectively, arise from neurospheres, with an increase in neuronal fate in groups with social interaction. In the second part of the study, the researchers analyzed the effect of different hormone and growth factor treatments and found that the response in both proliferation and differentiation potential may vary depending on the sociosexual context or sex. This study suggests that social interactions leading to pair bond formation alter the properties of SVZ cells, whereby proliferation and neurogenesis may have an impact on the establishment and maintenance of pair bonding.

Dopaminergic stimulation leads B-cell infiltration into the central nervous system upon autoimmunity.

BACKGROUND: Recent evidence has shown dopamine as a major regulator of inflammation. Accordingly, dopaminergic regulation of immune cells plays an important role in the physiopathology of inflammatory disorders. Multiple sclerosis (MS) is an inflammatory disease involving a CD4+ T-cell-driven autoimmune response to central nervous system (CNS) derived antigens. Evidence from animal models has suggested that B cells play a fundamental role as antigen-presenting cells (APC) re-stimulating CD4+ T cells in the CNS as well as regulating T-cell response by mean of inflammatory or anti-inflammatory cytokines. Here, we addressed the role of the dopamine receptor D3 (DRD3), which displays the highest affinity for dopamine, in B cells in animal models of MS. METHODS: Mice harbouring Drd3-deficient or Drd3-sufficient B cells were generated by bone marrow transplantation into recipient mice devoid of B cells. In these mice, we compared the development of experimental autoimmune encephalomyelitis (EAE) induced by immunization with a myelin oligodendrocyte glycoprotein (MOG)-derived peptide (pMOG), a model that leads to CNS-autoimmunity irrespective of the APC-function of B cells, or by immunization with full-length human MOG protein (huMOG), a model in which antigen-specific activated B cells display a fundamental APC-function in the CNS. APC-function was assessed in vitro by pulsing B cells with huMOG-coated beads and then co-culturing with MOG-specific T cells. RESULTS: Our data show that the selective Drd3 deficiency in B cells abolishes the disease development in the huMOG-induced EAE model. Mechanistic analysis indicates that although DRD3-signalling did not affect the APC-function of B cells, DRD3 favours the CNS-tropism in a subset of pro-inflammatory B cells in the huMOG-induced EAE model, an effect that was associated with higher CXCR3 expression. Conversely, the results show that the selective Drd3 deficiency in B cells exacerbates the disease severity in the pMOG-induced EAE model. Further analysis shows that DRD3-stimulation increased the expression of the CNS-homing molecule CD49d in a B-cell subset with anti-inflammatory features, thus attenuating EAE manifestation in the pMOG-induced EAE model. CONCLUSIONS: Our findings demonstrate that DRD3 in B cells exerts a dual role in CNS-autoimmunity, favouring CNS-tropism of pro-inflammatory B cells with APC-function and promoting CNS-homing of B cells with anti-inflammatory features. Thus, these results show DRD3-signalling in B cells as a critical regulator of CNS-autoimmunity.

A Late Cretaceous dinosaur and crocodyliform faunal association-based on isolate teeth and osteoderms-at Cerro Fortaleza Formation (Campanian-Maastrichtian) type locality, Santa Cruz, Argentina.

The Late Cretaceous dinosaur record in southern South America has been improved recently; particularly with findings from Chorrillo and Cerro Fortaleza formations, both bearing ankylosaur remains, a clade that was not previously recorded in the Austral Basin. The dinosaur fauna of the type locality of Cerro Fortaleza Formation is known from -and biased to- large-sized sauropod remains and a single described taxon, the titanosaur Dreadnoughtus schrani. Here, we report the taxonomic composition of a site preserving thirteen isolated teeth and several osteoderms belonging to three dinosaur clades (Abelisauridae, Titanosauria, and Nodosauridae), and at least one clade of notosuchian crocodyliforms (Peirosauridae). They come from sediments positioned at the mid-section of the Cerro Fortaleza Formation, which is Campanian-Maastrichtian in age, adding valuable information to the abundance and biodiversity of this Cretaceous ecosystem. Since non-titanosaur dinosaur bones are almost absent in the locality, the teeth presented here provide a window onto the archosaur biodiversity of the Late Cretaceous in southern Patagonia. The nodosaurid tooth and small armor ossicles represent the first record of ankylosaurs for this stratigraphic unit. The peirosaurid material also represents the most austral record of the clade in South America.

The Heteromeric Complex Formed by Dopamine Receptor D5 and CCR9 Leads the Gut Homing of CD4+ T Cells Upon Inflammation.

BACKGROUND AND AIMS: CD4+ T cells constitute central players in inflammatory bowel diseases (IBDs), driving inflammation in the gut mucosa. Current evidence indicates that CCR9 and the integrin α4ß7 are necessary and sufficient to imprint colonic homing on CD4+ T cells upon inflammation. Interestingly, dopaminergic signaling has been previously involved in leukocyte homing. Despite dopamine levels are strongly reduced in the inflamed gut mucosa, the role of dopamine in the gut homing of T cells remains unknown. Here, we study how dopaminergic signaling affects T cells upon gut inflammation. METHODS: Gut inflammation was induced by transfer of naïve T cells into Rag1-/- mice or by administration of dextran sodium sulfate. T cell migration and differentiation were evaluated by adoptive transfer of congenic lymphocytes followed by flow cytometry analysis. Protein interaction was studied by bioluminescence resonance energy transfer analysis, bimolecular fluorescence complementation, and in situ proximity ligation assays. RESULTS: We show the surface receptor providing colonic tropism to effector CD4+ T cells upon inflammation is not CCR9 but the complex formed by CCR9 and the dopamine receptor D5 (DRD5). Assembly of the heteromeric complex was demonstrated in vitro and in vivo using samples from mouse and human origin. The CCR9:DRD5 heteroreceptor was upregulated in the intestinal mucosa of IBD patients. Signaling assays confirmed that complexes behave differently than individual receptors. Remarkably, the disruption of CCR9:DRD5 assembly attenuated the recruitment of CD4+ T cells into the colonic mucosa. CONCLUSIONS: Our findings describe a key homing receptor involved in gut inflammation and introduce a new cell surface module in immune cells: macromolecular complexes formed by G protein-coupled receptors integrating the sensing of multiple molecular cues.

The demethylase inhibitor GSK-J4 limits inflammatory colitis by promoting de novo synthesis of retinoic acid in dendritic cells.

Dendritic cells (DCs) promote T-cell mediated tolerance to self-antigens and induce inflammation to innocuous-antigens. This dual potential makes DCs fundamental players in inflammatory disorders. Evidence from inflammatory colitis mouse models and inflammatory bowel diseases (IBD) patients indicated that gut inflammation in IBD is driven mainly by T-helper-1 (Th1) and Th17 cells, suggesting an essential role for DCs in the development of IBD. Here we show that GSK-J4, a selective inhibitor of the histone demethylase JMJD3/UTX, attenuated inflammatory colitis by reducing the inflammatory potential and increasing the tolerogenic features of DCs. Mechanistic analyses revealed that GSK-J4 increased activating epigenetic signals while reducing repressive marks in the promoter of retinaldehyde dehydrogenase isoforms 1 and 3 in DCs, enhancing the production of retinoic acid. This, in turn, has an impact on regulatory T cells (Treg) increasing their lineage stability and gut tropism as well as potentiating their suppressive activity. Our results open new avenues for the treatment of IBD patients.

A rapid spread of the stony coral tissue loss disease outbreak in the Mexican Caribbean.

Caribbean reef corals have experienced unprecedented declines from climate change, anthropogenic stressors and infectious diseases in recent decades. Since 2014, a highly lethal, new disease, called stony coral tissue loss disease, has impacted many reef-coral species in Florida. During the summer of 2018, we noticed an anomalously high disease prevalence affecting different coral species in the northern portion of the Mexican Caribbean. We assessed the severity of this outbreak in 2018/2019 using the AGRRA coral protocol to survey 82 reef sites across the Mexican Caribbean. Then, using a subset of 14 sites, we detailed information from before the outbreak (2016/2017) to explore the consequences of the disease on the condition and composition of coral communities. Our findings show that the disease outbreak has already spread across the entire region by affecting similar species (with similar disease patterns) to those previously described for Florida. However, we observed a great variability in prevalence and tissue mortality that was not attributable to any geographical gradient. Using long-term data, we determined that there is no evidence of such high coral disease prevalence anywhere in the region before 2018, which suggests that the entire Mexican Caribbean was afflicted by the disease within a few months. The analysis of sites that contained pre-outbreak information showed that this event considerably increased coral mortality and severely changed the structure of coral communities in the region. Given the high prevalence and lethality of this disease, and the high number of susceptible species, we encourage reef researchers, managers and stakeholders across the Western Atlantic to accord it the highest priority for the near future.

A new Palaeocene crocodylian from southern Argentina sheds light on the early history of caimanines.

Caimanines are crocodylians currently restricted to South and Central America and the oldest members are from lower Palaeocene localities of the Salamanca Formation (Chubut Province, Argentina). We report here a new caimanine from this same unit represented by a skull roof and partial braincase. Its phylogenetic relationships were explored in a cladistic analysis using standard characters and a morphogeometric two-dimensional configuration of the skull roof. The phylogenetic results were used for an event-based supermodel quantitative palaeobiogeographic analysis. The new species is recovered as the most basal member of the South American caimanines, and the Cretaceous North American lineage 'Brachychampsa and related forms' as the most basal Caimaninae. The biogeographic results estimated north-central North America as the ancestral area of Caimaninae, showing that the Cretaceous and Palaeocene species of the group were more widespread than thought and became regionally extinct in North America around the Cretaceous-Palaeocene boundary. A dispersal event from north-central North America during the middle Late Cretaceous explains the arrival of the group to South America. The Palaeogene assemblage of Patagonian crocodylians is composed of three lineages of caimanines as a consequence of independent dispersal events that occurred between North and South America and within South America around the Cretaceous-Palaeogene boundary.

Dopamine Receptor D5 Signaling Plays a Dual Role in Experimental Autoimmune Encephalomyelitis Potentiating Th17-Mediated Immunity and Favoring Suppressive Activity of Regulatory T-Cells.

A number of studies have shown pharmacologic evidence indicating that stimulation of type I dopamine receptor (DR), favors T-helper-17 (Th17)-mediated immunity involved in experimental autoimmune encephalomyelitis (EAE) and in some other inflammatory disorders. Nevertheless, the lack of drugs that might discriminate between DRD1 and DRD5 has made the pharmacological distinction between the two receptors difficult. We have previously shown genetic evidence demonstrating a relevant role of DRD5-signaling in dendritic cells (DCs) favoring the CD4+ T-cell-driven inflammation in EAE. However, the role of DRD5-signaling confined to CD4+ T-cells in the development of EAE is still unknown. Here, we analyzed the functional role of DRD5-signaling in CD4+ T-cell-mediated responses and its relevance in EAE by using a genetic approach. Our results show that DRD5-signaling confined to naive CD4+ T-cells exerts a pro-inflammatory effect promoting the development of EAE with a stronger disease severity. This pro-inflammatory effect observed for DRD5-signaling in naive CD4+ T-cells was related with an exacerbated proliferation in response to T-cell activation and to an increased ability to differentiate toward the Th17 inflammatory phenotype. On the other hand, quite unexpected, our results show that DRD5-signaling confined to Tregs strengthens their suppressive activity, thereby dampening the development of EAE manifestation. This anti-inflammatory effect of DRD5-signaling in Tregs was associated with a selective increase in the expression of glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), which has been described to play a critical role in the expansion of Tregs. Our findings here indicate a complex role for DRD5-signaling in CD4+ T-cells-driven responses potentiating early inflammation mediated by effector T-cells in EAE, but exacerbating suppressive activity in Tregs and thereby dampening disease manifestation in late EAE stages.

Dopaminergic Stimulation of Myeloid Antigen-Presenting Cells Attenuates Signal Transducer and Activator of Transcription 3-Activation Favouring the Development of Experimental Autoimmune Encephalomyelitis.

The dual potential to promote tolerance or inflammation to self-antigens makes dendritic cells (DCs) fundamental players in autoimmunity. Previous results have shown that stimulation of dopamine receptor D5 (DRD5) in DCs potentiates their inflammatory behaviour, favouring the development of experimental autoimmune encephalomyelitis (EAE). Here, we aimed to decipher the underlying mechanism and to test its relevance in multiple sclerosis (MS) patients. Our data shows that DRD5-deficiency confined to DCs in EAE mice resulted in reduced frequencies of CD4+ T-cell subsets with inflammatory potential in the central nervous system, including not only Th1 and Th17 cells but also granulocyte-macrophage colony-stimulating factor producers. Importantly, ex vivo depletion of dopamine from DCs resulted in a dramatic reduction of EAE severity, highlighting the relevance of an autocrine loop promoting inflammation in vivo. Mechanistic analyses indicated that DRD5-signalling in both mouse DCs and human monocytes involves the attenuation of signal transducer and activator of transcription 3-activation, a transcription factor that limits the production of the inflammatory cytokines interleukin (IL)-12 and IL-23. Furthermore, we found an exacerbated expression of all dopamine receptors in peripheral blood pro-inflammatory monocytes obtained from MS patients. These findings illustrate a novel mechanism by which myeloid antigen-presenting cells may trigger the onset of their inflammatory behaviour promoting the development of autoimmunity.

Galectin-8 as an immunosuppressor in experimental autoimmune encephalomyelitis and a target of human early prognostic antibodies in multiple sclerosis.

Galectin-8 (Gal-8) is a member of a glycan-binding protein family that regulates the immune system, among other functions, and is a target of antibodies in autoimmune disorders. However, its role in multiple sclerosis (MS), an autoimmune inflammatory disease of the central nervous system (CNS), remains unknown. We study the consequences of Gal-8 silencing on lymphocyte subpopulations and the development of experimental autoimmune encephalitis (EAE), to then assess the presence and clinical meaning of anti-Gal-8 antibodies in MS patients. Lgals8/Lac-Z knock-in mice lacking Gal-8 expression have higher polarization toward Th17 cells accompanied with decreased CCR6+ and higher CXCR3+ regulatory T cells (Tregs) frequency. These conditions result in exacerbated MOG35-55 peptide-induced EAE. Gal-8 eliminates activated Th17 but not Th1 cells by apoptosis and ameliorates EAE in C57BL/6 wild-type mice. ß-gal histochemistry reflecting the activity of the Gal-8 promoter revealed Gal-8 expression in a wide range of CNS regions, including high expression in the choroid-plexus. Accordingly, we detected Gal-8 in human cerebrospinal fluid, suggesting a role in the CNS immune-surveillance circuit. In addition, we show that MS patients generate function-blocking anti-Gal-8 antibodies with pathogenic potential. Such antibodies block cell adhesion and Gal-8-induced Th17 apoptosis. Furthermore, circulating anti-Gal-8 antibodies associate with relapsing-remitting MS (RRMS), and not with progressive MS phenotypes, predicting clinical disability at diagnosis within the first year of follow-up. Our results reveal that Gal-8 has an immunosuppressive protective role against autoimmune CNS inflammation, modulating the balance of Th17 and Th1 polarization and their respective Tregs. Such a role can be counteracted during RRMS by anti-Gal-8 antibodies, worsening disease prognosis. Even though anti-Gal-8 antibodies are not specific for MS, our results suggest that they could be a potential early severity biomarker in RRMS.

The histone demethylase inhibitor GSK-J4 limits inflammation through the induction of a tolerogenic phenotype on DCs.

As it has been established that demethylation of lysine 27 of histone H3 by the lysine-specific demethylase JMJD3 increases immune responses and thus elicits inflammation, we hypothesize that inhibition of JMJD3 may attenuate autoimmune disorders. We found that in vivo administration of GSK-J4, a selective inhibitor of JMJD3 and UTX, ameliorates the severity of experimental autoimmune encephalomyelitis (EAE). In vitro experiments revealed that the anti-inflammatory effect of GSK-J4 was exerted through an effect on dendritic cells (DCs), promoting a tolerogenic profile characterized by reduced expression of costimulatory molecules CD80/CD86, an increased expression of tolerogenic molecules CD103 and TGF-ß1, and reduced secretion of proinflammatory cytokines IL-6, IFN-γ, and TNF. Adoptive transfer of GSK-J4-treated DCs into EAE mice reduced the clinical manifestation of the disease and decreased the extent of inflammatory CD4+ T cells infiltrating the central nervous system. Notably, Treg generation, stability, and suppressive activity were all exacerbated by GSK-J4-treated DCs without affecting Th1 and Th17 cell production. Our data show that GSK-J4-mediated modulation of inflammation is achieved by a direct effect on DCs and that systemic treatment with GSK-J4 or adoptive transfer of GSK-J4-treated DCs ex vivo may be promising approaches for the treatment of inflammatory and autoimmune disorders.

Purinergic Signaling as a Regulator of Th17 Cell Plasticity.

T helper type 17 (Th17) lymphocytes, characterized by the production of interleukin-17 and other pro-inflammatory cytokines, are present in intestinal lamina propria and have been described as important players driving intestinal inflammation. Recent evidence, supporting the notion of a functional and phenotypic instability of Th17 cells, has shown that Th17 differentiate into type 1 regulatory (Tr1) T cells during the resolution of intestinal inflammation. Moreover, it has been suggested that the expression of CD39 ectonucleotidase endows Th17 cells with immunosuppressive properties. However, the exact role of CD39 ectonucleotidase in Th17 cells has not been studied in the context of intestinal inflammation. Here we show that Th17 cells expressing CD39 ectonucleotidase can hydrolyze ATP and survive to ATP-induced cell death. Moreover, in vitro-generated Th17 cells expressing the CD39 ectonucleotidase produce IL-10 and are less pathogenic than CD39 negative Th17 cells in a model of experimental colitis in Rag-/- mice. Remarkably, we show that CD39 activity regulates the conversion of Th17 cells to IL-10-producing cells in vitro, which is abrogated in the presence of ATP and the CD39-specific inhibitor ARL67156. All these data suggest that CD39 expression by Th17 cells allows the depletion of ATP and is crucial for IL-10 production and survival during the resolution of intestinal inflammation.

Stereoselective hydrogenation of aromatic alkynes using water, triethylsilane, or methanol, mediated and catalyzed by Ni(0) complexes.

The use of complexes of the type [(P-P)Ni(eta(2)-C,C-alkyne)] (P-P = 1,2-bis(di-isopropyl-phosphinoethane or 1,2-bis(diterbutylphosphino-ethane) in the presence of water, triethylsilane/water, or methanol as hydrogen sources yields the selective production of E- or Z- aromatic alkenes from the corresponding alkynes. For instance, in the case of diphenylacetylene (dpa) and water, a metal-mediated process was found to yield trans-stilbene stoichiometrically, whereas in the case of triethylsilane/water and methanol, a catalytic system (1% mol) was found. The catalytic systems gave >95% conversion to cis- or trans-stilbene, respectively. The use of a variety of substituents on the aromatic ring was also assessed. Deuterium-labeling studies using D(2)O allowed the confirmation of water as the hydrogen source for the alkyne reduction.