Methamphetamine Increases the Proportion of SIV-Infected Microglia/Macrophages, Alters Metabolic Pathways, and Elevates Cell Death Pathways: A Single-Cell Analysis.

Both substance use disorder and HIV infection continue to affect many individuals. Both have untoward effects on the brain, and the two conditions often co-exist. In the brain, macrophages and microglia are infectable by HIV, and these cells are also targets for the effects of drugs of abuse, such as the psychostimulant methamphetamine. To determine the interaction of HIV and methamphetamine, we isolated microglia and brain macrophages from SIV-infected rhesus monkeys that were treated with or without methamphetamine. Cells were subjected to single-cell RNA sequencing and results were analyzed by statistical and bioinformatic analysis. In the animals treated with methamphetamine, a significantly increased proportion of the microglia and/or macrophages were infected by SIV. In addition, gene encoding functions in cell death pathways were increased, and the brain-derived neurotropic factor pathway was inhibited. The gene expression patterns in infected cells did not cluster separately from uninfected cells, but clusters comprised of microglia and/or macrophages from methamphetamine-treated animals differed in neuroinflammatory and metabolic pathways from those comprised of cells from untreated animals. Methamphetamine increases CNS infection by SIV and has adverse effects on both infected and uninfected microglia and brain macrophages, highlighting the dual and interacting harms of HIV infection and drug abuse on the brain.

Proteomic fingerprints distinguish microglia, bone marrow, and spleen macrophage populations.

Mononuclear phagocytes (MP; dendritic cells, monocytes, tissue macrophages, and microglia) maintain tissue homeostasis and provide a first line of defense against invading pathogens. In specific circumstances, MPs also induce inflammatory responses and as such affect disease onset and progression. Despite intensive research into MP biology, little is known of the functional and molecular properties of individual MP subtypes. Using a novel proteomics platform, unique protein patterns and protein identities were observed among populations of spleen and bone marrow macrophages and microglia. Cells were obtained from C57BL/6 mice and were cultivated in macrophage colony-stimulating factor. MP subtypes were indistinguishable by morphological or antigenic criteria. Protein profiling by Surface Enhanced Laser Desorption Ionization-Time of Flight (SELDI-TOF) ProteinChip assays with weak cationic exchange chips showed unique MP spectral profiles. Corresponding protein fractions were recovered by high performance liquid chromatography and identified by liquid chromatography tandem mass spectrometry. The results provide a unique means to distinguish microglia from other MP subtypes.