EphA2 as a Diagnostic Imaging Target in Glioblastoma: A Positron Emission Tomography/Magnetic Resonance Imaging Study

Noninvasive imaging is a critical technology for diagnosis, classification, and subsequent treatment planning for patients with glioblastoma. It has been shown that the EphA2 receptor tyrosine kinase (RTK) is overexpressed in a number of tumors, including glioblastoma. Expression levels of Eph RTKs have been linked to tumor progression, metastatic spread, and poor patient prognosis. As EphA2 is expressed at low levels in normal neural tissues, this protein represents an attractive imaging target for delineation of tumor infiltration, providing an improved platform for image-guided therapy. In this study, EphA2-4B3, a monoclonal antibody specific to human EphA2, was labeled with Cu-64 through conjugation to the chelator 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The resulting complex was used as a positron emission tomography (PET) tracer for the acquisition of high-resolution longitudinal PET/magnetic resonance images. EphA2-4B3-NOTA-Cu-64 images were qualitatively and quantitatively compared to the current clinical standards of [F-18] FDOPA and gadolinium (Gd) contrast-enhanced MRI. We show that EphA2-4B3-NOTA-Cu-64 effectively delineates tumor boundaries in three different mouse models of glioblastoma. Tumor to brain contrast is significantly higher in EphA2-4B3-NOTA-Cu-64 images than in [F-18] FDOPA images and Gd contrast-enhanced MRI. Furthermore, we show that nonspecific uptake in the liver and spleen can be effectively blocked by a dose of nonspecific (isotype control) IgG

Direct evidence for transport of RNA from the mouse brain to the germline and offspring

Background The traditional concept that heritability occurs exclusively from the transfer of germline-restricted genetics is being challenged by the increasing accumulation of evidence confirming the existence of experience-dependent transgenerational inheritance. However, questions remain unanswered as to how heritable information can be passed from somatic cells. Previous studies have implicated the critical involvement of RNA in heritable transgenerational effects, and the high degree of mobility and genomic impact of RNAs in all organisms is an attractive model for the efficient transfer of genetic information. Results We hypothesized that RNA may be transported from a somatic tissue, in this case the brain, of an adult male mouse to the germline, and subsequently to embryos. To investigate this, we injected one hemisphere of the male mouse striatum with an AAV1/9 virus expressing human pre-MIR941 (MIR941). After 2, 8 and 16 weeks following injection, we used an LNA-based qPCR system to detect the presence of virus and human MIR941 in brain, peripheral tissues and embryos, from injected male mice mated with uninjected females. Virus was never detected outside of the brain. Verification of single bands of the correct size for MIR941 was performed using Sanger sequencing while quantitation demonstrated that a small percentage ( 1-8%) of MIR941 is transported to the germline and to embryos in about a third of the cases. Conclusions We show that somatic RNA can be transported to the germline and passed on to embryos, thereby providing additional evidence of a role for RNA in somatic cell-derived intergenerational effects

Granule neuron precursor cell proliferation is regulated by NFIX and intersectin 1 during postnatal cerebellar development

Cerebellar granule neurons are the most numerous neuronal subtype in the central nervous system. Within the developing cerebellum, these neurons are derived from a population of progenitor cells found within the external granule layer of the cerebellar anlage, namely the cerebellar granule neuron precursors (GNPs). The timely proliferation and differentiation of these precursor cells, which, in rodents occurs predominantly in the postnatal period, is tightly controlled to ensure the normal morphogenesis of the cerebellum. Despite this, our understanding of the factors mediating how GNP differentiation is controlled remains limited. Here, we reveal that the transcription factor nuclear factor I X (NFIX) plays an important role in this process. Mice lacking Nfix exhibit reduced numbers of GNPs during early postnatal development, but elevated numbers of these cells at postnatal day 15. Moreover, Nfix GNPs exhibit increased proliferation when cultured in vitro, suggestive of a role for NFIX in promoting GNP differentiation. At a mechanistic level, profiling analyses using both ChIP-seq and RNA-seq identified the actin-associated factor intersectin 1 as a downstream target of NFIX during cerebellar development. In support of this, mice lacking intersectin 1 also displayed delayed GNP differentiation. Collectively, these findings highlight a key role for NFIX and intersectin 1 in the regulation of cerebellar development

Lope y el protagonismo femenino: una perspectiva

Some considerations on feminine protagonism in the plays of Lope de Vega, with particular attention to the interest of the dramatist, during his large career, on the topic of the access of women to culture and especially literature

Donor T-cell–derived GM-CSF drives alloantigen presentation by dendritic cells in the gastrointestinal tract

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has recently emerged as an important pathogenic cytokine in acute graft-versus-host disease (GVHD), but the nature of the T-cell lineages secreting the cytokine and the mechanisms of action are less clear. Here we used interleukin 17A-fate reporter systems with transcriptional analysis and assays of alloantigen presentation to interrogate the origins of GM-CSF-secreting T cells and the effects of the cytokine on antigen-presenting cell (APC) function after experimental allogeneic stem cell transplantation (SCT). We demonstrated that although GM-CSF-secreting Th17 and non-Th17 cells expanded in the colon over time after SCT, the Th17 lineage expanded to represent 10% to 20% of the GM-CSF secreting T cells at this site by 4 weeks. Donor T-cell-derived GM-CSF expanded alloantigen-presenting donor dendritic cells (DCs) in the colon and lymph nodes. In the mesenteric lymph nodes, GM-CSF-dependent DCs primed donor T cells and amplified acute GVHD in the colon. We thus describe a feed-forward cascade whereby GM-CSF-secreting donor T cells accumulate and drive alloantigen presentation in the colon to amplify GVHD severity. GM-CSF inhibition may be a tractable clinical intervention to limit donor alloantigen presentation and GVHD in the lower gastrointestinal tract

A role for homologous recombination and abnormal cell-cycle progression in radioresistance of glioma-initiating cells

Glioblastoma multiforme (GBM) is the most common form of brain tumor with a poor prognosis and resistance to radiotherapy. Recent evidence suggests that glioma-initiating cells play a central role in radio resistance through DNA damage checkpoint activation and enhanced DNA repair. To investigate this inmore detail, we compared the DNA damage response in nontumor forming neural progenitor cells (NPC) and glioma-initiating cells isolated from GBM patient specimens. As observed for GBM tumors, initial characterization showed that glioma-initiating cells have long-term self-renewal capacity. They express markers identical toNPCs and have the ability to form tumors in an animal model. In addition, these cells are radioresistant to varying degrees, which could not be explained by enhanced nonhomologous end joining (NHEJ). Indeed, NHEJ in glioma-initiating cells was equivalent, or in some cases reduced, as compared with NPCs. However, there was evidence for more efficient homologous recombination repair in glioma-initiating cells. We did not observe a prolonged cell cycle nor enhanced basal activation of checkpoint proteins as reported previously. Rather, cell-cycle defects in the G1-S and S-phase checkpoints were observed by determining entry into S-phase and radioresistant DNA synthesis following irradiation. These data suggest that homologous recombination and cell-cycle checkpoint abnormalities may contribute to the radioresistance of glioma-initiating cells and that both processes may be suitable targets for therapy

IL-6 dysregulation originates in dendritic cells and initiates graft-versus-host disease via classical signaling

Graft-versus-host-disease (GVHD) after allogeneic stem cell transplantation (alloSCT) is characterized by interleukin 6 (IL-6) dysregulation. IL-6 can mediate effects via various pathways, including classical, trans and cluster signaling. Given the recent availability of agents that differentially inhibit these discrete signaling cascades, understanding the source, signaling and cellular targets of this cytokine is paramount to inform the design of clinical studies. Here we demonstrate that IL-6 secretion from recipient dendritic cells (DC) initiates the systemic dysregulation of this cytokine. Inhibition of DC-driven classical signaling following targeted IL-6 receptor (IL-6R) deletion in T-cells eliminated pathogenic donor Th17/Th22 cell differentiation and resulted in long-term survival. Following engraftment, donor DC assume the same role, maintaining classical IL-6 signaling-dependent GVHD responses. Surprisingly, cluster-signaling was not active after transplant, while inhibition of trans-signaling with sgp130Fc promoted severe, chronic cutaneous GVHD. The latter was a result of exaggerated polyfunctional Th22 cell expansion that was reversed by IL-22 deletion or IL-6R inhibition. Importantly, inhibition of IL-6 classical-signaling did not impair the graft-versus-leukemia effect. Together, these data highlight IL-6 classical-signaling and downstream Th17/Th22 differentiation as key therapeutic targets after alloSCT

Activation of the Zinc-sensing receptor GPR39 promotes T cell reconstitution after hematopoietic cell transplant in mice

: Prolonged lymphopenia represents a major clinical problem after cytoreductive therapies such as chemotherapy and the conditioning required for hematopoietic stem cell transplant (HSCT), contributing toward the risk of infections and malignant relapse. Restoration of T cell immunity is dependent on tissue regeneration in the thymus, the primary site of T cell development; although the capacity of the thymus to repair itself diminishes over lifespan. However, although boosting thymic function and T cell reconstitution is of considerable clinical importance, there are currently no approved therapies for treating lymphopenia. Here we found that Zinc (Zn), is critically important for both normal T cell development as well as repair after acute damage. Accumulated Zn in thymocytes during development was released into the extracellular milieu after HSCT conditioning, where it triggered regeneration by stimulating endothelial cell-production of BMP4 via the cell surface receptor GPR39. Dietary supplementation of Zn was sufficient to promote thymic function in a mouse model of allogeneic HSCT, including enhancing the number of recent thymic emigrants in circulation; although direct targeting of GPR39 with a small molecule agonist enhanced thymic function without the need for prior Zn accumulation in thymocytes. Together, these findings not only define an important pathway underlying tissue regeneration, but also offer an innovative preclinical approach to treat lymphopenia in HSCT recipients

Regulatory T cells suppress myeloma-specific immunity during autologous stem cell mobilization and transplantation

•T cells from bone marrow egress to blood during SCM and preferentially home back to marrow after adoptive transfer.•Treg depletion during SCM expands polyfunctional effector T cells in mobilized grafts and enhances antimyeloma immunity after ASCT. [Display omitted] Autologous stem cell transplantation (ASCT) is the standard of care consolidation therapy for eligible patients with myeloma but most patients eventually progress, an event associated with features of immune escape. Novel approaches to enhance antimyeloma immunity after ASCT represent a major unmet need. Here, we demonstrate that patient-mobilized stem cell grafts contain high numbers of effector CD8 T cells and immunosuppressive regulatory T cells (Tregs). We showed that bone marrow (BM)-residing T cells are efficiently mobilized during stem cell mobilization (SCM) and hypothesized that mobilized and highly suppressive BM-derived Tregs might limit antimyeloma immunity during SCM. Thus, we performed ASCT in a preclinical myeloma model with or without stringent Treg depletion during SCM. Treg depletion generated SCM grafts containing polyfunctional CD8 T effector memory cells, which dramatically enhanced myeloma control after ASCT. Thus, we explored clinically tractable translational approaches to mimic this scenario. Antibody-based approaches resulted in only partial Treg depletion and were inadequate to recapitulate this effect. In contrast, a synthetic interleukin-2 (IL-2)/IL-15 mimetic that stimulates the IL-2 receptor on CD8 T cells without binding to the high-affinity IL-2Ra used by Tregs efficiently expanded polyfunctional CD8 T cells in mobilized grafts and protected recipients from myeloma progression after ASCT. We confirmed that Treg depletion during stem cell mobilization can mitigate constraints on tumor immunity and result in profound myeloma control after ASCT. Direct and selective cytokine signaling of CD8 T cells can recapitulate this effect and represent a clinically testable strategy to improve responses after ASCT