Therefore, selective targeting of the activated status of 1 component of the innate immune system by WT TIDM peptide may be beneficial in AD as well as other disorders in which TLR2/MyD88 signaling plays a role in disease pathogenesis.
This study was designed to investigate whether pretreatment with the TLR2 receptor ligand can regulate microglia to produce interferon β (INFβ) in a rat model of Alzheimer's disease.
There is increasing evidence of an involvement of TLRs, especially TLR2, 4 and 9 in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).
These data led to the hypothesis that LPS acts on leukocyte and microglial TLR4-CD14/TLR2 receptors to produce NFkB mediated increases of cytokines which increase Aβ levels, damage oligodendrocytes and produce myelin injury found in AD brain.
Pro-inflammatory DAM emerged earlier in mouse models of AD and were characterized by pro-inflammatory genes (Tlr2, Ptgs2, Il12b, Il1b), surface marker CD44, potassium channel Kv1.3 and regulators (NFkb, Stat1, RelA) while anti-inflammatory DAM expressed phagocytic genes (Igf1, Apoe, Myo1e), surface marker CXCR4 with distinct regulators (LXRα/β, Atf1).
Inflammatory cytokine (TNFα, IL-6, IL-1β, IL-12p70) and chemokine (MIP-1α, MIP-1β, IL-8) production in response to LPS stimulation was very low in aMCI and nearly absent in mAD subjects.TLR2 expression was low only in aMCI.
These findings suggested that one common polymorphism in pri‑miR‑146a may contribute to the genetic predisposition to AD by disrupting the production of miR‑146a‑5p and affecting the expression and function of TLR2.
Phenotype analysis revealed differences in expression of CD16 (increased in mAD), NKG2A (decreased in aMCI), and TLR2 and TLR9 (both decreased in mAD).
In both cases, either AD or control group, TLR2 and TLR4 mRNAs expressions were positively correlated with the levels of proteins (TLR2: r=0.980 and 0.976,P<0.01; TLR4: r=0.938 and 0.970, P<0.01), respectively.
The differences in CD36 expression in TLR-2 polymorph AD patients compared to wild type AD patients and healthy controls may be associated with an enhanced susceptibility to skin infections with S. aureus.
Microglia are the immune cells of the brain, they are activated in the brain of Alzheimer's disease (AD) patients and mouse models of AD, and they express the innate immune receptor toll-like receptor 2 (TLR2).