CD9 and Aryl Hydrocarbon Receptor Are Markers of Human CD19+CD14+ Atypical B Cells and Are Dysregulated in Systemic Lupus Erythematous Disease.

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor whose expression regulates immune cell differentiation. Single-cell transcriptomic profiling was used to ascertain the heterogeneity of AHR expression in human B cell subpopulations. We identified a unique population of B cells marked by expression of AHR, CD9, and myeloid genes such as CD14 and CXCL8. Results were confirmed directly in human PBMCs and purified B cells at the protein level. TLR9 signaling induced CD14, CD9, and IL-8 protein expression in CD19+ B cells. CD14-expressing CD9+ B cells also highly expressed AHR and atypical B cell markers such as CD11c and TBET. In patients with active lupus disease, CD14+ and CD9+ B cells are dysregulated, with loss of CD9+ B cells strongly predicting disease severity and demonstrating the relevance of CD9+ B cells in systemic lupus erythematosus and autoimmune disease.

Evaluation of the anti-inflammatory effects of selected cannabinoids and terpenes from Cannabis Sativa employing human primary leukocytes.

Cannabis is well established as possessing immune modulating activity. The objective of this study was to evaluate the anti-inflammatory properties of selected cannabis-derived terpenes and cannabinoids. Based on their activity in cannabis-chemovar studies, α-pinene, trans-nerolidol, D-limonene, linalool and phytol were the selected terpenes evaluated. The cannabinoid compounds evaluated included cannabidivarin, cannabidiol, cannabinol, cannabichromene, cannabigerol and delta-9-tetrahydrocannabinol. Human PBMC were pretreated with each compound, individually, at concentrations extending from 0.001 to 10 µM and then stimulated with CpG (plasmacytoid dendritic cell), LPS (monocytes), or anti-CD3/CD28 (T cells). Proliferation, activation marker expression, cytokine production and phagocytosis, were quantified. Of the 21 responses assayed for each compound, cannabinoids showed the greatest immune modulating activity compared to their vehicle control. Delta-9-tetrahydrocannabinol possessed the greatest activity affecting 11 immune parameters followed by cannabidivarin, cannabigerol, cannabichromene, cannabinol and cannabidiol. α-Pinene showed the greatest immune modulating activity from the selected group of terpenes, followed by linalool, phytol, trans-nerolidol. Limonene had no effect on any of the parameters tested. Overall, these studies suggest that selected cannabis-derived terpenes displayed minimal immunological activity, while cannabinoids exhibited a broader range of activity. Compounds possessing anti-inflammatory effects may be useful in decreasing inflammation associated with a range of disorders, including neurodegenerative disorders.

Δ9-Tetrahydrocannabinol (THC) Impairs CD8+ T Cell-Mediated Activation of Astrocytes.

CD8+ T cells can contribute to neuroinflammation by secretion of inflammatory cytokines like interferon γ (IFNγ) and tumor necrosis factor α (TNFα). Astrocytes, a glial cell in the brain, can be stimulated by IFNγ and TNFα to secrete the inflammatory cytokines, monocyte chemotactic protein 1 (MCP-1), interleukin 6 (IL-6), and interferon-γ inducible protein 10 (IP-10). Δ9-Tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in Cannabis sativa, possesses potent anti-inflammatory activity. The objective of this investigation was to assess the effects of THC treatment on CD8+ T cell-mediated activation of astrocytes. CD3/CD28/IFNα- stimulated CD8+ T cells were treated with vehicle (0.03% EtOH) or THC and cocultured with U251 astrocytes. IP-10+, MCP-1+, and IL-6+ astrocytes were quantified by flow cytometry. LegendPlex™ was used to measure cytokine secretion by CD8+ T cells and flow cytometry was employed to quantify IFNγ, TNFα, and lysosomal-associated membrane protein 1 (LAMP-1) expression. Recombinant TNFα and IFNγ were used to stimulate MCP-1, IP-10, IL-6 responses in U251 astrocytes, which were measured by flow cytometry. Treatment with THC reduced CD8+ T cell-mediated induction of IP-10 and IL-6 responses in U251 astrocytes but had no effect on MCP-1. THC treatment differentially affected T cell effector functions such that IFNγ and degranulation responses were sensitive to THC-mediated ablation while TNFα was not. Lastly, THC treatment reduced the IFNγ-induced IP-10 response but had no effect on TNFα-induced MCP-1 response in U251 astrocytes. The results suggest that cannabinoid treatment can selectively reduce certain CD8+ T cell responses that contribute to stimulation of astrocytes. Graphical Abstract Treatment with THC can abate CD8+ T cell-dependent neuroinflammatory processes by inhibiting CD8+ cell differentiation into effector cells, suppressing CD8+ effector cell function, and reducing activation of astrocytes by CD8+ T cell-derived inflammatory cytokines.

Reversal of dendritic phenotypes in 16p11.2 microduplication mouse model neurons by pharmacological targeting of a network hub.

The architecture of dendritic arbors contributes to neuronal connectivity in the brain. Conversely, abnormalities in dendrites have been reported in multiple mental disorders and are thought to contribute to pathogenesis. Rare copy number variations (CNVs) are genetic alterations that are associated with a wide range of mental disorders and are highly penetrant. The 16p11.2 microduplication is one of the CNVs most strongly associated with schizophrenia and autism, spanning multiple genes possibly involved in synaptic neurotransmission. However, disease-relevant cellular phenotypes of 16p11.2 microduplication and the driver gene(s) remain to be identified. We found increased dendritic arborization in isolated cortical pyramidal neurons from a mouse model of 16p11.2 duplication (dp/+). Network analysis identified MAPK3, which encodes ERK1 MAP kinase, as the most topologically important hub in protein-protein interaction networks within the 16p11.2 region and broader gene networks of schizophrenia-associated CNVs. Pharmacological targeting of ERK reversed dendritic alterations associated with dp/+ neurons, outlining a strategy for the analysis and reversal of cellular phenotypes in CNV-related psychiatric disorders.