Immune checkpoints refer to a plethora of inhibitory pathways of the immune system that play a crucial role in maintaining self-tolerance and in tuning the duration and amplitude of physiological immune responses to minimize collateral tissue damages. The breakdown of this delicate balance leads to pathological conditions, including cancer. Indeed, tumor cells can develop multiple mechanisms to escape from immune system defense, including the activation of immune checkpoint pathways. The development of monoclonal antibodies, targeting inhibitory immune checkpoints, has provided an immense breakthrough in cancer therapy. Immune checkpoint inhibitors (ICI), initially developed to reverse functional exhaustion in T cells, recently emerged as important actors in natural killer (NK)-cell-based immunotherapy. Moreover, the discovery that also helper innate lymphoid cells (ILCs) express inhibitory immune checkpoints, suggests that these molecules might be targeted on ILCs, to modulate their functions in the tumor microenvironment. Recently, other strategies to achieve immune checkpoint blockade have been developed, including miRNA exploiting systems. Herein, we provide an overview of the current knowledge on inhibitory immune checkpoints on NK cells and ILCs and we discuss how to target these innate lymphocytes by ICI in both solid tumors and hematological malignancies.

Glial cells play important roles in the development and homeostasis of metazoan nervous systems. However, while their involvement in the development and function in the central nervous system (CNS) of vertebrates is increasingly well understood, much less is known about invertebrate glia and the evolutionary history of glial cells more generally. An investigation into amphioxus glia is therefore timely, as this organism is the best living proxy for the last common ancestor of all chordates, and hence provides a window into the role of glial cell development and function at the transition of invertebrates and vertebrates. We report here our findings on amphioxus glia as characterized by molecular probes correlated with anatomical data at the transmission electron microscopy (TEM) level. The results show that amphioxus glial lineages express genes typical of vertebrate astroglia and radial glia, and that they segregate early in development, forming what appears to be a spatially separate cell proliferation zone positioned laterally, between the dorsal and ventral zones of neural cell proliferation. Our study provides strong evidence for the presence of vertebrate‐type glial cells in amphioxus, while highlighting the role played by segregated progenitor cell pools in CNS development. There are implications also for our understanding of glial cells in a broader evolutionary context, and insights into patterns of precursor cell deployment in the chordate nerve cord.

Background: Roles of astrocytes in the modulatory effects of oxytocin (OT) in central nervous system are increasingly considered. Nevertheless, OT effects on gliotransmitter release have been neglected. Methods: In purified astrocyte processes from adult rat striatum, we assessed OT receptor (OTR) and adenosine A2A receptor expression by confocal analysis. The effects of receptors activation on glutamate release from the processes were evaluated; A2A-OTR heteromerization was assessed by co-immunoprecipitation and PLA. Structure of the possible heterodimer of A2A and OT receptors was estimated by a bioinformatic approach. Results: Both A2A and OT receptors were expressed on the same astrocyte processes. Evidence for A2A-OTR receptor-receptor interaction was obtained by measuring the release of glutamate: OT inhibited the evoked glutamate release, while activation of A2A receptors, per se ineffective, abolished the OT effect. Biochemical and biophysical evidence for A2A-OTR heterodimers on striatal astrocytes was also obtained. The residues in the transmembrane domains 4 and 5 of both receptors are predicted to be mainly involved in the heteromerization. Conclusions: When considering effects of OT in striatum, modulation of glutamate release from the astrocyte processes and of glutamatergic synapse functioning, and the interaction with A2A receptors on the astrocyte processes should be taken into consideration.

Tissue repair is an adaptive and widespread metazoan response. It is characterised by different cellular mechanisms and complex signalling networks that involve numerous growth factors and cytokines. In higher animals, transforming growth factor-β (TGF-β) signalling plays a fundamental role in wound healing. In order to evaluate the involvement of TGF superfamily members in lower invertebrate tissue regeneration, sequences for putative TGF ligands and receptors were isolated from the transcriptome of the marine sponge Chondrosia reniformis. We identified seven transcripts that coded for TGF superfamily ligands and three for TGF superfamily receptors. Phylogenetically, C. reniformis TGF ligands were not grouped into any TGF superfamily clades and thus presumably evolved independently, whereas the TGF receptors clustered in the Type I receptor group. We performed gene expression profiling of these transcripts in sponge regenerating tissue explants. Data showed that three ligands (TGF1, TGF3 and TGF6) were mainly expressed during early regeneration and seemed to be involved in stem cell maintenance, whereas two others (TGF4 and TGF5) were strongly upregulated during late regeneration and thus were considered pro-differentiating factors. The presence of a strong TGF inhibitor, SB431542, blocked the restoration of the exopinacoderm layer in the sponge explants, confirming the functional involvement of the TGF pathway in tissue regeneration in these early evolved animals.

Cephalochordates, commonly called amphioxus or lancelets, are widely regarded as a useful proxy for the chordate ancestor. In recent decades, expression patterns of important developmental genes have been used extensively to infer homologies between cephalochordate and vertebrate embryos. Such comparisons provided important insight into cephalochordate biology and the origin of vertebrate traits. Most of the developmental expression data are collected using whole-mount in situ hybridization that allows the distributions of specific transcripts to be detected in fixed embryos. Here, we describe an experimental pipeline for production of small amounts of functional antibodies directed against amphioxus antigens for use in immunohistochemical labelling. In this pilot study, we generated antibodies against b-catenin and the transcription factors FoxA, Lhx1, Lhx3 and Pax6. We demonstrate the usefulness of antibodies by performing immunostainings on fixed specimens of B. lanceolatum and B. floridae. We anticipate that amphioxus-specific antibodies will provide a useful tool for high-resolution labelling of individual cells within the embryo and for determining the subcellular localization of the corresponding proteins. KEY WORDS: Branchiostoma, amphioxus, antibody, expression patternCephalochordates, commonly called amphioxus or lancelets, are regarded as a key animal group for understanding the origin of vertebrates, and a useful proxy to the ancestral chordate condition. This position has recently been affirmed especially thanks to the access to genome sequence data (Holland et al., 2008;Huang et al., 2014;Putnam et al., 2008), introduction of novel techniques (Acemel et al., 2016;Kozmikova and Kozmik, 2015;Li et al., 2017;Yue et al., 2016), and establishment of amphioxus as a model species for evolutionary developmental studies (for review see Bertrand and Escriva (2011)). Cephalochordates include three genera, namely Branchiostoma, Asymmetron and Epigonychtys. The phylogenetic relationships within the extant amphioxus lineage were recently investigated providing divergence time estimates and suggesting a rather recent diversification (Igawa et al., 2017). For example, the estimated divergence times among species within the Branchiostoma genus (22.6 +/-2.3 Mya for B.lanceolatum -B. floridae split) are comparable to those among rodents belonging to Muridae family (such as mouse and rat). Close phylogenetic relationship is mirrored by a high degree of coding sequence , which permits you to Share (copy and redistribute the material in any medium or format) and Adapt (remix, transform, and build upon the material for any purpose, even commercially), providing you give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. Printed in Spain Abbreviations used in this paper: TH, tyrosine hydroxylase; WMISH, whole mount in situ hybridization.identity (Holland et al., 2008;H...