Ferroptosis and pathogenesis of neuritic plaques in Alzheimer's Disease.

Neuritic plaques are pathognomonic and terminal lesions of Alzheimer's Disease (AD). They embody AD pathogenesis because they harbor in one space critical pathologic features of the disease: amyloid deposits, neurofibrillary degeneration (NFD), neuroinflammation, iron accumulation. Neuritic plaques are thought to arise from the conversion of diffuse extracellular deposits of amyloid beta protein (Aβ), and it is believed that during conversion amyloid toxicity creates the dystrophic neurites of neuritic plaques, as well as neurofibrillary tangles (NFTs).

Receptor-interacting protein kinase 2 (RIPK2) profoundly contributes to post-stroke neuroinflammation and behavioral deficits with microglia as unique perpetrators.

Background: Receptor-interacting protein kinase 2 (RIPK2) is a serine/threonine kinase whose activity propagates inflammatory signaling through its association with pattern recognition receptors (PRRs) and subsequent TAK1, NF-κB, and MAPK pathway activation. After stroke, dead and dying cells release a host of damage-associated molecular patterns (DAMPs) that activate PRRs and initiate a robust inflammatory response. We hypothesize that RIPK2 plays a damaging role in the progression of stroke injury by enhancing the neuroinflammatory response to stroke and that global genetic deletion or microglia-specific conditional deletion of Ripk2 will be protective following ischemic stroke.

Methamphetamine induces a low dopamine transporter expressing state without altering the total number of peripheral immune cells.

Methamphetamine is a widely abused psychostimulant and one of the main targets of dopamine transporter (DAT). Methamphetamine reduces DAT-mediated dopamine uptake and stimulates dopamine efflux leading to increased synaptic dopamine levels many folds above baseline. Methamphetamine also targets DAT-expressing peripheral immune cells, reduces wound healing and increases infection susceptibility.

Who Knew? Dopamine Transporter Activity Is Critical in Innate and Adaptive Immune Responses.

The dopamine transporter (DAT) regulates the dimension and duration of dopamine transmission. DAT expression, its trafficking, protein-protein interactions, and its activity are conventionally studied in the CNS and within the context of neurological diseases such as Parkinson's Diseases and neuropsychiatric diseases such as drug addiction, attention deficit hyperactivity and autism. However, DAT is also expressed at the plasma membrane of peripheral immune cells such as monocytes, macrophages, T-cells, and B-cells.

The complex role of inflammation and gliotransmitters in Parkinson's disease.

Our understanding of the role of innate and adaptive immune cell function in brain health and how it goes awry during aging and neurodegenerative diseases is still in its infancy. Inflammation and immunological dysfunction are common components of Parkinson's disease (PD), both in terms of motor and non-motor components of PD. In recent decades, the antiquated notion that the central nervous system (CNS) in disease states is an immune-privileged organ, has been debunked.

Microglia senescence occurs in both substantia nigra and ventral tegmental area.

During aging humans lose midbrain dopamine neurons, but not all dopamine regions exhibit vulnerability to neurodegeneration. Microglia maintain tissue homeostasis and neuronal support, but microglia become senescent and likely lose some of their functional abilities. Since aging is the greatest risk factor for Parkinson's disease, we hypothesized that aging-related changes in microglia and neurons occur in the vulnerable substantia nigra pars compacta (SNc) but not the ventral tegmental area (VTA).

HIV-1 Tat regulation of dopamine transmission and microglial reactivity is brain region specific.

The transactivator of transcription protein, HIV-1 Tat, is linked to neuroAIDS, where degeneration of dopamine neurons occurs. Using a mouse model expressing GFAP-driven Tat protein under doxycycline (Dox) regulation, we investigated microglial-neuronal interactions in the rostral substantia nigra pars compacta (SNc). Immunohistochemistry for microglia and tyrosine hydroxylase (TH) showed that the ratio of microglia to dopamine neurons is smaller in the SNc than in the ventral tegmental area (VTA) and that this difference is maintained following 7-day Dox exposure in wild type animals.