The human brain has enormously complex cellular diversity and connectivities fundamental to our neural functions, yet difficulties in interrogating individual neurons has impeded understanding of the underlying transcriptional landscape. We developed a scalable approach to sequence and quantify RNA molecules in isolated neuronal nuclei from post-mortem brain, generating 3,227 sets of single neuron data from six distinct regions of the cerebral cortex. Using an iterative clustering and classification approach, we identified 16 neuronal subtypes that were further annotated on the basis of known markers and cortical cytoarchitecture. These data demonstrate a robust and scalable method for identifying and categorizing single nuclear transcriptomes, revealing shared genes sufficient to distinguish novel and orthologous neuronal subtypes as well as regional identity within the human brain.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that is present in all tissues examined to date. LPA signals extracellularly via cognate G protein-coupled receptors to mediate cellular processes such as survival, proliferation, differentiation, migration, adhesion and morphology. These LPA-influenced processes impact many aspects of organismal development. In particular, LPA signalling has been shown to affect fertility and reproduction, formation of the nervous system, and development of the vasculature. Here and in the accompanying poster, we review the developmentally related features of LPA signalling.

Adult females develop greater antibody responses to influenza vaccines than males. We hypothesized that female-biased immunity and protection would be dependent on the extent of virus diversity as well as molecular mechanisms in B cells which constrain the breadth of epitope recognition.

This article is available online at http://www.jlr.org binding parameters as determined by backscattering interferometry. J. Lipid Res. 2019. 60: 212-217.Supplementary key words lipid • phospholipids • endocannabinoid • optical measurement • molecular interaction • binding assay Lysophospholipid (LP) signaling involving cognate G protein-coupled receptors (GPCRs) for lysophosphatidic acid (LPA), sphingosine-1-phosphate (S1P), and other lipids has revealed a vast biology affecting the development and function of most, if not all, organ systems and shown etiological or therapeutic involvement in diseases, including those of the nervous and immune systems, as well as in disease conditions like cancer and fibrosis (1-9). A key step in LP signaling is orthosteric GPCR engagement by binding of a cognate ligand to its receptor, followed by G-protein transduction (10, 11). LP receptor binding is thus a necessary step for both naturally occurring lipids and synthetic ligands that, combined with other members of the GPCR superfamily, account for 40% of currently marketed drugs (12).LP GPCRs are members of the rhodopsin-like family of receptors (class A) from which 40 lipid GPCRs have now been identified (7). Crystal structures for seven lipid GPCRs have been solved including three LP receptors [LPA 1 (13), LPA 6 (14), and S1P 1 (15)] (16).Despite these receptor structural advances, classical pharmacological GPCR-ligand binding assays using radioligands Abstract Lysophosphatidic acid (LPA) activates cognate G protein-coupled receptors (GPCRs) to initiate biological signaling cascades. Lysophospholipid (LP) receptor binding properties remain incompletely assessed because of difficulties with ligand lipophilicity and lipid "stickiness." These inherent attributes produce high levels of nonspecific binding within cell-membrane preparations used to assess GPCRs, as has been shown in classical binding assays using radiolabeled ligands, making accurate measurements of lipid binding kinetics difficult to achieve. Backscattering interferometry (BSI) is an optical technology that measures molecular binding interactions by reporting changes in the refractive index of a solution after binding events. Here, we report the use of BSI to assess LPA 1 for its ability to bind to naturally occurring lipids and a synthetic LPA 1 antagonist (ONO-9780307), under both primary-and competition-binding conditions. Assessment of 12 different lipids demonstrated that the known LP ligand, 1-oleoyl-LPA, as well as an endocannabinoid metabolite, anandamide phosphate, are specific ligands for LPA 1 , whereas other LPs tested were not. Newly determined dissociation constants (K d values) for orthosteric lipid ligands approximated 10 9 M, substantially lower (i.e., with higher affinity) than measured K d values in classical binding or cell-based assays. These results demonstrate that BSI may have particular utility in assessing binding interactions between lipid receptors and their lipid ligands and could provide new screening approaches for lipid recept...

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