ROLE OF THE INFLAMMASOMES IN NEUROINFLAMMATION ASSOCIATED WITH ALZHEIMER'S DISEASE

Interleukin-1 beta [IL1β] and the "inflammasome" protein complex, the main regulator of the IL1β production, plays an important role in neuroinflammation observed in Alzheimer's disease [AD]. AD is a neurodegenerative disease, whose prevalence is estimated to be increasing over the decades; the neuropathological characteristic most common are beta-amyloid [Aβ] plaques, whose deposition are the key element for the triggering of oxidative and pro-inflammatory processes by the activated microglia. The interaction between activated microglia and plaques A induces the release of pro-inflammatory cytokines, such as interleukin-6 [IL6], or neurotoxic factors, such as tumor necrosis factor-α [TNFα]. The amyloid plaques production is due on one hand to the hyper-pathological accumulation of oligomers, on the other hand to the reduced extracellular clearance of the same. The amyloid is physiologically eliminated from the brain tissue through blood vessels, towards which migrates in the course of its biological time [years]. The result is the accumulation of Aβ at first around these vessels, and then into the brain tissue. The insoluble amyloid can act as superantigen, activating a chronic inflammatory response both humoral and cell-mediated activation. The inflammation tissue is initially mediated by activated microglia but, it was already shown a link between brain inflammation and that device. In addition to microglia, new monocytes are constantly recruited from the periphery to the nervous tissue overcoming the blood-brain barrier; stimulated monocytes show the same macrophage phenotype. Neuroinflammation is therefore a fundamental etiopathogenetic moment in the genesis of cognitive impairment and dementia related to Alzheimer's disease. Both post-mortem biopsies and immunohistochemistry, have revealed the presence of activated microglia in Aβ, plaques. Immunohistochemical studies have also revealed positivity for IL-1, markers of innate immunity activation mediated by macrophages and microglia. The inflammatory insult is probably most responsible for neuronal loss. Currently a diagnosis of AD is only possible through post-mortem analysis of the brain tissue, which is why in recent years have been researched and identified biological indicators and hormonal disease, which could be useful in the early diagnosis of AD. These indicators are also expressed by peripheral leukocytes, cells readily available, representing a footprint of that which occurs at the level of different brain areas in vivo. For this, the white blood cells represent useful elements to study the changes that develop in the brain. Therefore, in the second part of the project, to better investigate the possible involvement of inflammosome peripherally, peripheral blood mononuclear cells [PBMC] were isolated from individuals diagnosed with Mini-Mental State Examination [MMSE] and classified as follows: 1] individuals with mild but measurable changes in thinking skills defined mild cognitive impairment [MCI] [MMSE 24-29]; 2] patients with moderate disease AD [mild] [MMSE 19-24]; 3] individuals with severe AD pathology [MMSE <19]. Finally they were enrolled even healthy individuals [HC] of equal sex and age as a control group. PBMC were stimulated with LPS and Aβ [1-42] to evaluate the 'expression of the genes and the proteins involved in the inflammasome pathway and to evaluate proinflammatory cytokines production. The results suggest an involvement of at least two different inflammasomes-complexes in neuroinflammation associated with Alzheimer's disease. Based on these results, the second part of the project aimed at completing the outline of inflammasome activation in neuroinflammation context by investigating WT or NLRP3 and Asc knockout mouse Primary Microglia cells . Data obtained confirm the NLRP3-inflammasome involvement in the inflammatory cytokines production making this complex a potential drug target for improving the therapy of Alzheimer's Disease.