Macrophage-induced inflammation affects hippocampal plasticity and neuronal development in a murine model of HIV-1 encephalitis.
Cognitive, behavioral, and motor impairments, during progressive human immunodeficiency virus type 1 (HIV-1) infection, are linked to activation of brain mononuclear phagocytes (MP; perivascular macrophages and microglia). Activated MPs effect a giant cell encephalitis and neuroinflammatory responses that are mirrored in severe combined immunodeficient (SCID) mice injected with human monocyte-derived macrophages (MDM). Whether activated human MDMs positioned in the basal ganglia affect hippocampal neuronal plasticity, the brain subregion involved in learning and memory, is unknown. Thus, immunohistochemical techniques were used for detection of newborn neurons (polysialylated neuronal cell adhesion molecule [PSA-NCAM]) and cell proliferation (Ki-67) to assay MDM effects on neuronal development in mouse models of HIV-1 encephalitis. Immunodeficient (C.B.-17/SCID and nonobese diabetic/SCID, NOD/SCID) and immune competent (C.B.-17) mice were injected with uninfected or HIV-1-infected MDM. Sham-operated or unmanipulated mice served as controls. Neuronal plasticity was evaluated in the hippocampal dentate gyrus (DG) at days 7 and 28. By day 7, increased numbers of Ki-67+ cells, PSA-NCAM+ cells and dendrites in DG were observed in sham-operated animals. In contrast, significant reductions in neuronal precursors and altered neuronal morphology paralleled increased microglial activation in both HIV-1-infected and uninfected MDM-injected animals. DG cellular composition was restored at day 28. We posit that activated MDM induce inflammation and diminish DG neuronal plasticity. These data provide novel explanations for the cognitive impairments manifested during advanced HIV-1 infection.
Poluektova
Larisa
L
Laboratory of Neuroregeneration, Department of Pharmacology and Experimental Neuroscience, Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA. lpoluekt@unmc.edu
Meyer
Vakara
V
Walters
Lisa
L
Paez
Ximena
X
Gendelman
Howard E
HE
D015526:AIDS Dementia Complex / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D003072:Cognition Disorders / Q000378:metabolism / Q000503:physiopathology / Q000821:virology; D004195:Disease Models, Animal; D004660:Encephalitis / Q000378:metabolism* / Q000503:physiopathology / Q000821:virology; D005911:Gliosis / Q000378:metabolism / Q000503:physiopathology / Q000821:virology; D015497:HIV-1 / Q000502:physiology; D006624:Hippocampus / Q000276:immunology / Q000503:physiopathology* / Q000821:virology; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000821:virology; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D017628:Microglia / Q000276:immunology / Q000821:virology; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D009473:Neuronal Plasticity / Q000276:immunology*; D009474:Neurons / Q000276:immunology* / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism; D013234:Stem Cells / Q000276:immunology
D019394:Ki-67 Antigen; D039842:Neural Cell Adhesion Molecule L1; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule