Human natural killer (NK) cells in peripheral blood perform many functions, and classification of specific subsets has been a longstanding goal. We report single-cell RNA sequencing of NK cells, comparing gene expression in unstimulated and interleukin (IL)-2–activated cells from healthy cytomegalovirus (CMV)-negative donors. Three NK cell subsets resembled well-described populations; CD56brightCD16−, CD56dimCD16+CD57−, and CD56dimCD16+CD57+. CD56dimCD16+CD57− cells subdivided to include a population with higher chemokine mRNA and increased frequency of killer-cell immunoglobulin-like receptor expression. Three novel human blood NK cell populations were identified: a population of type I interferon–responding NK cells that were CD56neg; a population exhibiting a cytokine-induced memory-like phenotype, including increased granzyme B mRNA in response to IL-2; and finally, a small population, with low ribosomal expression, downregulation of oxidative phosphorylation, and high levels of immediate early response genes indicative of cellular activation. Analysis of CMV+ donors established that CMV altered the proportion of NK cells in each subset, especially an increase in adaptive NK cells, as well as gene regulation within each subset. Together, these data establish an unexpected diversity in blood NK cells and provide a new framework for analyzing NK cell responses in health and disease.

Background:The function of KLF11/TIEG2 under stressful conditions is undefined. Results: KLF11 increases brain MAO expression through its promoter and a chromatin partner, which can be enhanced by stress. Conclusion: This is the first elucidation of mechanisms underlying stress-induced KLF11-MAO up-regulation. Significance: This novel KLF11-MAO pathway may play an important role in stress-related brain disorders.

We are interested in the positive allosteric modulation of neuronal nicotinic acetylcholine (ACh) receptors and have recently shown that the anthelmintic compound morantel potentiates by enhancing channel gating of the ␣3␤2 subtype. Based on the demonstration that morantelelicited currents were inhibited by the classic ACh competitor dihydro-␤-erythroidine in a noncompetitive manner and that morantel still potentiates at saturating concentrations of agonist (Wu et al., 2008), we hypothesized that morantel binds at the noncanonical ␤2(ϩ)/ ␣3(Ϫ) subunit interface. In the present study, we created seven cysteine-substituted subunits by site-directed mutagenesis, choosing residues in the putative morantel binding site with the aid of structural homology models. We coexpressed the mutant subunits and their respective wild-type partners in Xenopus oocytes and characterized the morantel potentiation of ACh-evoked currents, as well as morantel-evoked currents, before and after treatment with a variety of methanethiosulfonate (MTS)-based compounds, using voltageclamp recordings. The properties of four of the seven mutants, two residues on each side of the interface, were changed by MTS treatments. Coapplication with ACh enhanced the extent of MTS modification for ␣3A106C␤2 and ␣3␤2S192C receptors. The activities of two mutants, ␣3T115C␤2 and ␣3␤2T150C, were dramatically altered by MTS modification. For ␣3␤2T150C, while peak current amplitudes were reduced, potentiation was enhanced. For ␣3T115C␤2, both current amplitudes and potentiation were reduced. MTS modification and morantel were mutually inhibitory: MTS treatment decreased morantel-evoked currents and morantel decreased the rate of MTS modification. We conclude that the four residues showing MTS effects contribute to the morantel binding site.

Background: Chromatin remodeling mechanisms utilized by Krüppel-like factor proteins remain poorly defined.Results: Krüppel-like factor 11 directly recruits heterochromatin protein 1α to promoters in a sequence-specific manner.Conclusion: Coupling to heterochromatin protein 1 α and its histone methyltransferase underlies Krüppel-like factor-mediated gene expression and tumor suppression.Significance: This data advances our understanding of how chromatin-mediated mechanisms achieve these functions with increased specificity for target genes.

Background: Chromatin-mediated events utilized by Krüppel-Like factors in neurons remain undefined.Results: Krüppel-Like factor 11 couples to antagonistic chromatin pathways (p300 versus heterochromatin protein 1) to regulate the dopamine D2 receptor gene.Conclusion: This is the first description of mechanisms underlying Krüppel-like factor-mediated functions in neurons.Significance: This knowledge expands our understanding of chromatin-mediated mechanisms that influence homeostasis in highly specialized cells.