Ketoprofen-Based Polymer-Drug Nanoparticles Provide Anti-Inflammatory Properties to HA/Collagen Hydrogels.

Current limitations of wound dressings for treating chronic wounds require the development of novel approaches. One of these is the immune-centered approach, which aims to restore the pro-regenerative and anti-inflammatory properties of macrophages. Under inflammatory conditions, ketoprofen nanoparticles (KT NPs) can reduce pro-inflammatory markers of macrophages and increase anti-inflammatory cytokines. To assess their suitability as part of wound dressings, these NPs were combined with hyaluronan (HA)/collagen-based hydro- (HGs) and cryogels (CGs). Different HA and NP concentrations and loading techniques for NP incorporation were used. The NP release, gel morphology, and mechanical properties were studied. Generally, colonialization of the gels with macrophages resulted in high cell viability and proliferation. Furthermore, direct contact of the NPs to the cells reduced the level of nitric oxide (NO). The formation of multinucleated cells on the gels was low and further decreased by the NPs. For the HGs that produced the highest reduction in NO, extended ELISA studies showed reduced levels of the pro-inflammatory markers PGE2, IL-12 p40, TNF-α, and IL-6. Thus, HA/collagen-based gels containing KT NPs may represent a novel therapeutic approach for treating chronic wounds. Whether effects observed in vitro translate into a favorable profile on skin regeneration in vivo will require rigorous testing.

Antiaging properties of antioxidant photoprotective polymeric nanoparticles loaded with coenzyme-Q10.

Skin is the most extensive organ within our body. It is continually subjected to stress factors, among which ultraviolet irradiation, a key factor responsible in skin aging since it leads to reactive oxygen species production. In order to fight against these oxidative species, the human body has an innate robust antioxidant mechanism composed of several different substances, one of which is coenzyme Q10. Its capacity to increase cellular energy production and excellent antioxidant properties have been proved, as well as its antiaging properties being able to attenuate cellular damage induced by ultraviolet irradiation in human dermal fibroblasts. However, its high hydrophobicity and photolability hampers its therapeutic potential. In this context, the objective of this work consists of the preparation of chitosan-rosmarinic acid conjugate-based nanoparticles to encapsulate coenzyme Q10 with high encapsulation efficiencies in order to improve its bioavailability and broaden its therapeutic use in skin applications. Hyaluronic acid coating was performed giving stable nanoparticles at physiological pH with 382 ± 3 nm of hydrodynamic diameter (0.04 ± 0.02 polydispersity) and - 18 ± 3 mV of surface charge. Release kinetics studies showed a maximum of 82 % mass release of coenzyme Q10 after 40 min, and radical scavenger activity assay confirmed the antioxidant character of chitosan-rosmarinic acid nanoparticles. Hyaluronic acid-coated chitosan-rosmarinic acid nanoparticles loaded with coenzyme Q10 were biocompatible in human dermal fibroblasts and exhibited interesting photoprotective properties in ultraviolet irradiated cells. In addition, nanoparticles hindered the production of reactive oxygen species, interleukin-6 and metalloproteinase-1, as well as caspase-9 activation maintaining high viability values upon irradiation of dermal fibroblasts. Overall results envision a great potential of these nanovehicles for application in skin disorders or antiaging treatments.

Injectable Tripeptide/Polymer Nanoparticles Supramolecular Hydrogel: A Candidate for the Treatment of Inflammatory Pathologies.

Supramolecular peptide-based hydrogels attract great attention in several fields, i.e., biomedicine, catalysis, energy, and materials chemistry, due to the noncovalent nature of the self-assembly and functional tunable properties defined by the amino acid sequence. In this work, we developed an injectable hybrid supramolecular hydrogel whose formation was triggered by electrostatic interactions between a phosphorylated tripeptide, Fmoc-FFpY (F: phenylalanine, pY: phosphorylated tyrosine), and cationic polymer nanoparticles made of vinylimidazole and ketoprofen (poly(HKT-co-VI) NPs). Hydrogel formation was assessed through inverted tube tests, and its fibrillary structure, around polymer NPs, was observed by transmission electron microscopy. Interestingly, peptide self-assembly yields the formation of nontwisted and twisted fibers, which could be attributed to ß-sheets and α-helix structures, respectively, as characterized by circular dichroism and infrared spectroscopies. An increase of the elastic modulus of the Fmoc-FFpY/polymer NPs hybrid hydrogels was observed with peptide concentration as well as its injectability property, due to its shear thinning behavior and self-healing ability. After checking their stability under physiological conditions, the cytotoxicity properties of these hybrid hydrogels were evaluated in contact with human dermal fibroblasts (FBH) and murine macrophages (RAW 264.7). Finally, the Fmoc-FFpY/polymer NPs hybrid hydrogels exhibited a great nitric oxide reduction (∼67%) up to basal values of pro-inflammatory RAW 264.7 cells, thus confirming their excellent anti-inflammatory properties for the treatment of localized inflammatory pathologies.

Chitosan - Rosmarinic acid conjugates with antioxidant, anti-inflammatory and photoprotective properties.

Rosmarinic acid is an attractive candidate for skin applications because of its antioxidant, anti-inflammatory, and photoprotective functions, however, its poor bioavailability hampers its therapeutic outcome. In this context, synthesis of polymer conjugates is an alternative to enlarge its applications. This work describes the synthesis of novel water-soluble chitosan - rosmarinic acid conjugates (CSRA) that have great potential for skin applications. Chitosan was functionalized with different contents of rosmarinic acid as confirmed by ATR-FTIR, 1H NMR and UV spectroscopies. CSRA conjugates presented three-fold radical scavenger capacity compared to the free phenolic compound. Films were prepared by solvent-casting procedure and the biological activity of the lixiviates was studied in vitro. Results revealed that lixiviates reduced activation of inflamed macrophages, improved antibacterial capacity against E. coli with respect to native chitosan and free rosmarinic acid, and also attenuated UVB-induced cellular damage and reactive oxygen species production in fibroblasts and keratinocytes.

Hyaluronic acid (HA)-coated naproxen-nanoparticles selectively target breast cancer stem cells through COX-independent pathways.

Cytotoxic chemotherapy continues to be the main therapeutic option for patients with metastatic breast cancer. Several studies have reported a significant association between chronic inflammation, carcinogenesis and the presence of cancer stem cells (CSC). We hypothesized that the use of non-steroidal anti-inflammatory drugs targeted to the CSC population could help reducing tumor progression and dissemination in otherwise hard to treat metastatic breast cancer. Within this study cationic naproxen (NAP)-bearing polymeric nanoparticles (NPs) were obtained by self-assembly and they were coated with hyaluronic acid (HA) via electrostatic interaction. HA-coated and uncoated NAP-bearing NPs with different sizes were produced by changing the ionic strength of the aqueous preparation solutions (i.e. 300 and 350 nm or 100 and 130 nm in diameter, respectively). HA-NPs were fully characterized in terms of physicochemical parameters and biological response in cancer cells, macrophages and endothelial cells. Our results revealed that HA-coating of NPs provided a better control in NAP release and improved their hemocompatibility, while ensuring a strong CSC-targeting in MCF-7 breast cancer cells. Furthermore, the best polymeric NPs formulation significantly (p < 0.001) reduced MCF-7 cells viability when compared to free drug (i.e. 45 ± 6% for S-HA-NPs and 87 ± 10% for free NAP) by p53-dependent induction of apoptosis; and the migration of these cell line was also significantly (p < 0.01) reduced by the nano-formulated NAP (i.e. 76.4% of open wound for S-HA-NPs and 61.6% of open wound for NAP). This increased anti-cancer activity of HA-NAP-NPs might be related to the induction of apoptosis through alterations of the GSK-3ß-related COX-independent pathway. Overall, these findings suggest that the HA-NAP-NPs have the potential to improve the treatment of advanced breast cancer by increasing the anti-proliferative effect of NAP within the CSC subpopulation.

Senescent accelerated prone 8 (SAMP8) mice as a model of age dependent neuroinflammation.

BACKGROUND: Aging and age-related diseases are strong risk factors for the development of neurodegenerative diseases. Neuroinflammation (NIF), as the brain's immune response, plays an important role in aged associated degeneration of central nervous system (CNS). There is a need for well characterized animal models that will allow the scientific community to understand and modulate this process. METHODS: We have analyzed aging-phenotypical and inflammatory changes of brain myeloid cells (bMyC) in a senescent accelerated prone aged (SAMP8) mouse model, and compared with their senescence resistant control mice (SAMR1). We have performed morphometric methods to evaluate the architecture of cellular prolongations and determined the appearance of Iba1+ clustered cells with aging. To analyze specific constant brain areas, we have performed stereology measurements of Iba1+ cells in the hippocampal formation. We have isolated bMyC from brain parenchyma (BP) and choroid plexus plus meningeal membranes (m/Ch), and analyzed their response to systemic lipopolysaccharide (LPS)-driven inflammation. RESULTS: Aged 10 months old SAMP8 mice present many of the hallmarks of aging-dependent neuroinflammation when compared with their SAMR1 control, i.e., increase of protein aggregates, presence of Iba1+ clusters, but not an increase in the number of Iba1+ cells. We have further observed an increase of main inflammatory mediator IL-1ß, and an augment of border MHCII+Iba1+ cells. Isolated CD45+ bMyC from brain parenchyma (BP) and choroid plexus plus meningeal membranes (m/Ch) have been analyzed, showing that there is not a significant increase of CD45+ cells from the periphery. Our data support that aged-driven pro-inflammatory cytokine interleukin 1 beta (IL-1ß) transcription is enhanced in CD45+BP cells. Furthermore, LPS-driven systemic inflammation produces inflammatory cytokines mainly in border bMyC, sensed to a lesser extent by the BP bMyC, showing that IL-1ß expression is further augmented in aged SAMP8 compared to control SAMR1. CONCLUSION: Our data validate the SAMP8 model to study age-associated neuroinflammatory events, but careful controls for age and strain are required. These animals show morphological changes in their bMyC cell repertoires associated to age, corresponding to an increase in the production of pro-inflammatory cytokines such as IL-1ß, which predispose the brain to an enhanced inflammatory response after LPS-systemic challenge.

Dendritic Cells and Microglia Have Non-redundant Functions in the Inflamed Brain with Protective Effects of Type 1 cDCs.

Brain CD11c+ cells share features with microglia and dendritic cells (DCs). Sterile inflammation increases brain CD11c+ cells, but their phenotype, origin, and functions remain largely unknown. We report that, after cerebral ischemia, microglia attract DCs to the inflamed brain, and astroglia produce Flt3 ligand, supporting development and expansion of CD11c+ cells. CD11c+ cells in the inflamed brain are a complex population derived from proliferating microglia and infiltrating DCs, including a major subset of OX40L+ conventional cDC2, and also cDC1, plasmacytoid, and monocyte-derived DCs. Despite sharing certain morphological features and markers, CD11c+ microglia and DCs display differential expression of pattern recognition receptors and chemokine receptors. DCs excel CD11c- and CD11c+ microglia in the capacity to present antigen through MHCI and MHCII. Of note, cDC1s protect from brain injury after ischemia. We thus reveal aspects of the dynamics and functions of brain DCs in the regulation of inflammation and immunity.

The TLR4-MyD88 Signaling Axis Regulates Lung Monocyte Differentiation Pathways in Response to Streptococcus pneumoniae.

Streptococcus pneumoniae is the main cause of bacterial pneumonia, a condition that currently produces significant global morbidity and mortality. The initial immune response to this bacterium occurs when the innate system recognizes common motifs expressed by many pathogens, events driven by pattern recognition receptors like the Toll-like family receptors (TLRs). In this study, lung myeloid-cell populations responsible for the innate immune response (IIR) against S. pneumoniae, and their dependence on the TLR4-signaling axis, were analyzed in TLR4-/- and Myeloid-Differentiation factor-88 deficient (MyD88-/-) mice. Neutrophils and monocyte-derived cells were recruited in infected mice 3-days post-infection. Compared to wild-type mice, there was an increased bacterial load in both these deficient mouse strains and an altered IIR, although TLR4-/- mice were more susceptible to bacterial infection. These mice also developed fewer alveolar macrophages, weaker neutrophil infiltration, less Ly6Chigh monocyte differentiation and a disrupted classical and non-classical monocyte profile. The pro-inflammatory cytokine profile (CXCL1, TNF-α, IL-6, and IL-1ß) was also severely affected by the lack of TLR4 and no induction of Th1 was observed in these mice. The respiratory burst (ROS production) after infection was profoundly dampened in TLR4-/- and MyD88-/- mice. These data demonstrate the complex dynamics of myeloid populations and a key role of the TLR4-signaling axis in the IIR to S. pneumoniae, which involves both the MyD88 and TRIF (Toll/IL-1R domain-containing adaptor-inducing IFN-ß) dependent pathways.

Anti-Inflammatory Polymeric Nanoparticles Based on Ketoprofen and Dexamethasone.

Polymeric nanoparticles that combine dexamethasone and naproxen reduce inflammation and synergistically inhibit Interleukin-12b (Il12b) transcription in macrophages. This effect can be the result of a cyclooxygenase-dependent or a cyclooxygenase-independent mechanism. The aim of this work is to obtain potent anti-inflammatory polymeric nanoparticles by the combination of dexamethasone and ketoprofen, one of the most efficient cyclooxygenase-inhibitors among non-steroidal anti-inflammatory drugs, with appropriate hydrodynamic properties to facilitate accumulation and co-release of drugs in inflamed tissue. Nanoparticles are spherical with hydrodynamic diameter (117 ± 1 nm), polydispersity (0.139 ± 0.004), and surface charge (+30 ± 1 mV), which confer them with high stability and facilitate both macrophage uptake and internalization pathways to favor their retention at the inflamed areas and lysosomal degradation and drug release, respectively. In vitro biological studies concluded that the dexamethasone-loaded ketoprofen-bearing system is non-cytotoxic and efficiently reduces lipopolysaccharide-induced nitric oxide release. The RT-qPCR analysis shows that the ketoprofen nanoparticles were able to reduce to almost basal levels the expression of tested pro-inflammatory markers and increase the gene expression of anti-inflammatory cytokines under inflammatory conditions. However, the synergistic inhibition of Il12b observed in nanoparticles that combine dexamethasone and naproxen was not observed in nanoparticles that combine dexamethasone and ketoprofen, suggesting that the synergistic trans-repression of Il12b observed in the first case was not mediated by cyclooxygenase-dependent pathways.

Polymeric Nanoparticles that Combine Dexamethasone and Naproxen for the Synergistic Inhibition of Il12b Transcription in Macrophages.

Recent studies have demonstrated in vivo synergistic immunosuppressive and anti-inflammatory capacity of dexamethasone (Dx) and naproxen (NAP) in collagen-induced arthritis (CIA) rats. However, the molecular basis of this synergistic effect is barely understood. The low solubility of these drugs and their adverse effects hamper their efficacy on the treatment of inflammatory processes making nanoparticulated systems promising candidates to overcome these drawbacks. The aim of this work is the preparation of polymeric nanoparticles (NPs) that combine NAP and Dx in different concentrations, and the evaluation of the expression of key genes related to autoimmune diseases like CIA. To do so, self-assembled polymeric NPs that incorporate covalently-linked NAP and physically entrapped Dx are designed to have hydrodynamic properties that, according to bibliography, may improve retention and colocalization of both drugs at inflammation sites. The rapid uptake of NPs by macrophages is demonstrated using coumarine-6-loaded NPs. Dx is efficiently encapsulated and in vitro biological studies demonstrate that the Dx-loaded NAP-bearing NPs are noncytotoxic and reduce lipopolysaccharide-induced NO released levels at any of the tested concentrations. Moreover, at the molecular level, a significant synergistic reduction of Il12b transcript gene expression when combining Dx and NAP is demonstrated.

Anti-inflammatory Surface Coatings Based on Polyelectrolyte Multilayers of Heparin and Polycationic Nanoparticles of Naproxen-Bearing Polymeric Drugs.

Immune response to biomaterials can produce chronic inflammation and fibrosis leading to implant failure, which is related to the surface properties of the biomaterials. This work describes the preparation and characterization of polyelectrolyte multilayer (PEM) coatings that combine the anti-inflammatory activity of heparin as polyanion with the potential release of Naproxen, a nonsteroidal anti-inflammatory drug from polymeric nanoparticles (NP) with cationic surface charge. The polyelectrolyte multilayers were characterized by physical methods to estimate multilayer growth, thickness, zeta potential, and topography. It was found that multilayers with NP had negative zeta potentials and expressed a viscoelastic behavior, while studies of topography showed that nanoparticles formed continuous surface coatings. THP-1-derived macrophages were used to study short-term anti-inflammatory activity (time scale 48 h), showing that PEM that contained heparin reduced cell adhesion and IL1-ß secretion, when compared to those with polystyrenesulfonate, used as alternative polyanion in multilayer formation. On the other hand, the presence of NP in PEM was related to a reduced foreign body giant cell formation after 15 days, when compared to PEM that contained chitosan as alternative polycation, which suggests a long-term anti-inflammatory effect of Naproxen-containing nanoparticles. It was also shown that macrophages were able to take up NP from multilayers, which indicates a release of Naproxen by digestion of NP in the lysosomal compartment. These findings indicate that surface coatings composed of heparin and Naproxen-based NP on implants such as biosensors have the potential to attenuate foreign body reaction after implantation, which may improve the long-term functionality of implants.

NFATc3 controls tumour growth by regulating proliferation and migration of human astroglioma cells.

Calcium/Calcineurin/Nuclear Factor of Activated T cells (Ca/CN/NFAT) signalling pathway is the main calcium (Ca2+) dependent signalling pathway involved in the homeostasis of brain tissue. Here, we study the presence of NFATc members in human glioma by using U251 cells and a collection of primary human glioblastoma (hGB) cell lines. We show that NFATc3 member is the predominant member. Furthermore, by using constitutive active NFATc3 mutant and shRNA lentiviral vectors to achieve specific silencing of this NFATc member, we describe cytokines and molecules regulated by this pathway which are required for the normal biology of cancer cells. Implanting U251 in an orthotopic intracranial assay, we show that specific NFATc3 silencing has a role in tumour growth. In addition NFATc3 knock-down affects both the proliferation and migration capacities of glioma cells in vitro. Our data open the possibility of NFATc3 as a target for the treatment of glioma.

Neuronal and Glial Differentiation of Human Neural Stem Cells Is Regulated by Amyloid Precursor Protein (APP) Levels.

Amyloid precursor protein (APP) is implicated in neural development as well as in the pathology of Alzheimer's disease (AD); however, its biological function still remains unclear. It has been reported that APP stimulates the proliferation and neuronal differentiation of neural stem cells (NSCs), while other studies suggest an important effect enhancing gliogenesis in NSCs. As expected, APP protein/mRNA is detected in hNS1 cells, a model cell line of human NSCs, both under proliferation and throughout the differentiation period. To investigate the potential function that APP plays in cell fate specification and differentiation of hNS1 cells, we transiently increased human APP levels in these cells and analyzed its cell intrinsic effects. Our data indicate that increased levels of APP induce early cell cycle exit and instructively direct hNS1 cell fate towards a glial phenotype, while decreasing neuronal differentiation. Since elevated APP levels also enhanced APP intracellular domain (AICD)-immunoreactivity, these effects could be, in part, mediated by the APP/AICD system. The AICD domain can play a potential role in signal transduction by its molecular interaction with different target genes such as GSK3B, whose expression was also increased in APP-overexpressing cells that, in turn, may contribute to promoting gliogenesis and inhibiting neurogenesis in NSCs. These data suggest an important action of APP in modulating hNSCs differentiation (probably in an AICD-GSK-3ß-dependent manner) and may thus be important for the future development of stem cell therapy strategies for the diseased mammalian brain.

CD45 expression discriminates waves of embryonic megakaryocytes in the mouse.

Embryonic megakaryopoiesis starts in the yolk sac on gestational day 7.5 as part of the primitive wave of hematopoiesis, and it continues in the fetal liver when this organ is colonized by hematopoietic progenitors between day 9.5 and 10.5, as the definitive hematopoiesis wave. We characterized the precise phenotype of embryo megakaryocytes in the liver at gestational day 11.5, identifying them as CD41++CD45-CD9++CD61+MPL+CD42c+ tetraploid cells that express megakaryocyte-specific transcripts and display differential traits when compared to those present in the yolk sac at the same age. In contrast to megakaryocytes from adult bone marrow, embryo megakaryocytes are CD45- until day 13.5 of gestation, as are both the megakaryocyte progenitors and megakaryocyte/erythroid-committed progenitors. At gestational day 11.5, liver and yolk sac also contain CD41+CD45+ and CD41+CD45- cells. These populations, and that of CD41++CD45-CD42c+ cells, isolated from liver, differentiate in culture into CD41++CD45-CD42c+ proplatelet-bearing megakaryocytes. Also present at this time are CD41-CD45++CD11b+ cells, which produce low numbers of CD41++CD45-CD42c+ megakaryocytes in vitro, as do fetal liver cells expressing the macrophage-specific Csf receptor-1 (Csf1r/CD115) from MaFIA transgenic mice, which give rise poorly to CD41++CD45-CD42c+ embryo megakaryocytes both in vivo and in vitro In contrast, around 30% of adult megakaryocytes (CD41++CD45++CD9++CD42c+) from C57BL/6 and MaFIA mice express CD115. We propose that differential pathways operating in the mouse embryo liver at gestational day 11.5 beget CD41++CD45-CD42c+ embryo megakaryocytes that can be produced from CD41+CD45- or from CD41+CD45+ cells, at difference from those from bone marrow.

DNGR-1 in dendritic cells limits tissue damage by dampening neutrophil recruitment.

Host injury triggers feedback mechanisms that limit tissue damage. Conventional type 1 dendritic cells (cDC1s) express dendritic cell natural killer lectin group receptor-1 (DNGR-1), encoded by the gene Clec9a, which senses tissue damage and favors cross-presentation of dead-cell material to CD8+ T cells. Here we find that DNGR-1 additionally reduces host-damaging inflammatory responses induced by sterile and infectious tissue injury in mice. DNGR-1 deficiency leads to exacerbated caerulein-induced necrotizing pancreatitis and increased pathology during systemic Candida albicans infection without affecting fungal burden. This effect is B and T cell-independent and attributable to increased neutrophilia in DNGR-1-deficient settings. Mechanistically, DNGR-1 engagement activates SHP-1 and inhibits MIP-2 (encoded by Cxcl2) production by cDC1s during Candida infection. This consequently restrains neutrophil recruitment and promotes disease tolerance. Thus, DNGR-1-mediated sensing of injury by cDC1s serves as a rheostat for the control of tissue damage, innate immunity, and immunopathology.

Role of Amyloid Precursor Protein (APP) and Its Derivatives in the Biology and Cell Fate Specification of Neural Stem Cells.

Amyloid precursor protein (APP) is a member of the APP family of proteins, and different enzymatic processing leads to the production of several derivatives that are shown to have distinct biological functions. APP is involved in the pathology of Alzheimer's disease (AD), the most common neurodegenerative disorder causing dementia. Furthermore, it is believed that individuals with Down syndrome (DS) have increased APP expression, due to an extra copy of chromosome 21 (Hsa21), that contains the gene for APP. Nevertheless, the physiological function of APP remains unclear. It is known that APP plays an important role in neural growth and maturation during brain development, possibly by influencing proliferation, cell fate specification and neurogenesis of neural stem cells (NSCs). Proteolytic cleavage of APP occurs mainly via two mutually exclusive pathways, the non-amyloidogenic pathway or the amyloidogenic pathway. Other alternative pathways (η-secretase, δ-secretase and meprin pathways) have also been described for the physiological processing of APP. The different metabolites generated from these pathways, including soluble APPα (sAPPα), soluble APPß (sAPPß), ß-amyloid (Aß) peptides and the APP intracellular domain (AICD), have different functions determined by their structural differences, equilibrium and concentration with respect to other fragments derived from APP. This review discusses recent observations regarding possible functions of APP and its proteolytic derivatives in the biology and phenotypic specification of NSCs. This can be important for a better understanding of the pathogenesis and the development of future therapeutic applications for AD and/or DS, diseases in which alterations in neurogenesis have been described.

Altered marginal zone and innate-like B cells in aged senescence-accelerated SAMP8 mice with defective IgG1 responses.

Aging has a strong impact on the activity of the immune system, enhancing susceptibility to pathogens and provoking a predominant pre-inflammatory status, whereas dampening responses to vaccines in humans and mice. Here, we demonstrate a loss of marginal zone B lymphocytes (MZ, CD19+CD45R+CD21++CD23lo) and a decrease of naive B cells (CD19+IgD+), whereas there is an enhancement of a CD19+CD45Rlo innate-like B cell population (B1REL) and the so-called aged B cell compartment (ABC, CD45R+CD21loCD23loCD5-CD11b-) in aged senescence-accelerated (SAMP8) mice but not in aged senescence-resistant (SAMR1) mice. These changes in aged SAMP8 mice were associated with lower IgG isotype levels, displaying low variable gene usage repertoires of the immunoglobulin heavy chain (VH) diversity, with a diminution on IgG1-memory B cells (CD11b-Gr1-CD138-IgM-IgD-CD19+CD38+IgG1+), an increase in T follicular helper (TFH, CD4+CXCR5+PD1+) cell numbers, and an altered MOMA-1 (metallophilic macrophages) band in primary follicles. LPS-mediated IgG1 responses were impaired in the B1REL and ABC cell compartments, both in vitro and in vivo. These data demonstrate the prominent changes to different B cell populations and in structural follicle organization that occur upon aging in SAMP8 mice. These novel results raise new questions regarding the importance of the cellular distribution in the B cell layers, and their effector functions needed to mount a coordinated and effective humoral response.

An Update on Human Stem Cell-Based Therapy in Parkinson's Disease.

CDATA[Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease and it is characterized by the progressive loss of dopaminergic neurons of the substantia nigra pars compacta (SNpc). Current pharmacological treatments for PD are only symptomatic and unfortunately there is still no cure for this disorder. Stem cell technology has become an attractive option to investigate and treat PD. Indeed, transplantation of fetal ventral mesencephalic cells into PD brains have provided proof of concept that cell replacement therapy can be beneficial for some patients, greatly improving their motor symptoms. However, ethical and practical aspects of tissue availability limit its widespread clinical use. Hence, the need of alternative cell sources are based on the use of different types of stem cells. Stem cell-based therapies can be beneficial by acting through several mechanisms such as cell replacement, trophic actions and modulation of inflammation. Here we review recent and current remarkable clinical studies involving stem cell-based therapy for PD and provide an overview of the different types of stem cells available nowadays, their main properties and how they are developing as a possible therapy for PD treatment.

DNGR-1(+) dendritic cells are located in meningeal membrane and choroid plexus of the noninjured brain.

The role and different origin of brain myeloid cells in the brain is central to understanding how the central nervous system (CNS) responds to injury. C-type lectin receptor family 9, member A (DNGR-1/CLEC9A) is a marker of specific DC subsets that share functional similarities, such as CD8α(+) DCs in lymphoid tissues and CD103(+) CD11b(low) DCs in peripheral tissues. Here, we analyzed the presence of DNGR-1 in DCs present in the mouse brain (bDCs). Dngr-1/Clec9a mRNA is expressed mainly in the meningeal membranes and choroid plexus (m/Ch), and its expression is enhanced by fms-like tyrosine kinase 3 ligand (Flt3L), a cytokine involved in DC homeostasis. Using Clec9a(egfp/egfp) mice, we show that Flt3L induces accumulation of DNGR-1-EGFP(+) cells in the brain m/Ch. Most of these cells also express major histocompatibility complex class II (MHCII) molecules. We also observed an increase in specific markers of cDC CD8α+ cells such as Batf-3 and Irf-8, but not of costimulatory molecules such as Cd80 and Cd86, indicating an immature phenotype for these bDCs in the noninjured brain. The presence of DNGR-1 in the brain provides a potential marker for the study of this specific brain cell subset. Knowledge and targeting of brain antigen presenting cells (APCs) has implications for the fight against brain diseases such as neuroinflammation-based neurodegenerative diseases, microbe-induced encephalitis, and brain tumors such as gliomas.

NFAT transcription factors regulate survival, proliferation, migration, and differentiation of neural precursor cells.

The study of factors that regulate the survival, proliferation, and differentiation of neural precursor cells (NPCs) is essential to understand neural development as well as brain regeneration. The Nuclear Factor of Activated T Cells (NFAT) is a family of transcription factors that can affect these processes besides playing key roles during development, such as stimulating axonal growth in neurons, maturation of immune system cells, heart valve formation, and differentiation of skeletal muscle and bone. Interestingly, NFAT signaling can also promote cell differentiation in adults, participating in tissue regeneration. The goal of the present study is to evaluate the expression of NFAT isoforms in NPCs, and to investigate its possible role in NPC survival, proliferation, migration, and differentiation. Our findings indicate that NFAT proteins are active not only in neurogenic brain regions such as hippocampus and subventricular zone (SVZ), but also in cultured NPCs. The inhibition of NFAT activation with the peptide VIVIT reduced neurosphere size and cell density in NPC cultures by decreasing proliferation and increasing cell death. VIVIT also decreased NPC migration and differentiation of astrocytes and neurons from NPCs. In addition, we identified NFATc3 as a predominant NFAT isoform in NPC cultures, finding that a constitutively-active form of NFATc3 expressed by adenoviral infection reduces NPC proliferation, stimulates migration, and is a potent inducer of NPC differentiation into astrocytes and neurons. In summary, our work uncovers active roles for NFAT signaling in NPC survival, proliferation and differentiation, and highlights its therapeutic potential for tissue regeneration.