ABSTRACT
Alzheimer's disease (AD) brains exhibit plaques and tangles in association with inflammation. The non-receptor tyrosine kinase Abl is linked to neuro-inflammation in AD. Abl inhibition by nilotinib or bosutinib facilitates amyloid clearance and may decrease inflammation. Transgenic mice that express Dutch, Iowa and Swedish APP mutations (TgAPP) and display progressive Aß plaque deposition were treated with tyrosine kinase inhibitors (TKIs) to determine pre-plaque effects on systemic and CNS inflammation using milliplex® ELISA. Plaque Aß was detected at 4months in TgAPP and pre-plaque intracellular Aß accumulation (2.5months) was associated with changes of cytokines and chemokines prior to detection of glial changes. Plaque formation correlated with increased levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-1α, IL-1ß) and markers of immunosuppressive and adaptive immunity, including, IL-4, IL-10, IL-2, IL-3, Vascular Endothelial Growth Factor (VEGF) and IFN-γ. An inverse relationship of chemokines was observed as CCL2 and CCL5 were lower than WT mice at 2months and significantly increased after plaque appearance, while soluble CX3CL1 decreased. A change in glial profile was only robustly detected at 6months in Tg-APP mice and TKIs reduced astrocyte and dendritic cell number with no effects on microglia, suggesting alteration of brain immunity. Nilotinib decreased blood and brain cytokines and chemokines and increased CX3CL1. Bosutinib increased brain and blood IL-10 and CX3CL1, suggesting a protective role for soluble CX3CL1. Taken together these data suggest that TKIs regulate systemic and CNS immunity and may be useful treatments in early AD through dual effects on amyloid clearance and immune modulation.
Subject(s)
Aniline Compounds/pharmacology , Brain/drug effects , Neuroimmunomodulation/drug effects , Nitriles/pharmacology , Plaque, Amyloid/drug therapy , Pyrimidines/pharmacology , Quinolines/pharmacology , Aging/drug effects , Aging/pathology , Aging/physiology , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Animals , Astrocytes/pathology , Astrocytes/physiology , Brain/pathology , Brain/physiopathology , Cytokines/metabolism , Disease Models, Animal , Enzyme Inhibitors/pharmacology , Female , Humans , Intracellular Space/drug effects , Intracellular Space/metabolism , Male , Mice, Inbred C57BL , Mice, Transgenic , Microglia/pathology , Microglia/physiology , Neuroimmunomodulation/physiology , Peptide Fragments/metabolism , Plaque, Amyloid/pathology , Plaque, Amyloid/physiopathology , Protein-Tyrosine Kinases/antagonists & inhibitors , Protein-Tyrosine Kinases/metabolismABSTRACT
Parkinson's disease (PD) is a motor disorder that involves death of dopaminergic neurons in the substantia nigra pars compacta. Parkin is an autosomal recessive gene that is mutated in early onset PD. We investigated the role of parkin and autophagic clearance in postmortem nigrostriatal tissues from 22 non-familial sporadic PD patients and 15 control samples. Parkin was insoluble with altered cytosolic expression in the nigrostriatum of sporadic PD. Parkin insolubility was associated with lack of degradation of ubiquitinated proteins and accumulation of α-Synuclein and parkin in autophagosomes, suggesting autophagic defects in PD. To test parkin's role in mediating autophagic clearance, we used lentiviral gene transfer to express human wild type or mutant parkin (T240R) with α-Synuclein in the rat striatum. Lentiviral expression of α-Synuclein led to accumulation of autophagic vacuoles, while co-expression of parkin with α-Synuclein facilitated autophagic clearance. Subcellular fractionation showed accumulation of α-Synuclein and tau hyper-phosphorylation (p-Tau) in autophagosomes in gene transfer models, similar to the effects observed in PD brains, but parkin expression led to protein deposition into lysosomes. However, parkin loss of function mutation did not affect autophagic clearance. Taken together, these data suggest that functional parkin regulates autophagosome clearance, while decreased parkin solubility may alter normal autophagy in sporadic PD.
Subject(s)
Autophagy/physiology , Corpus Striatum/physiopathology , Mesencephalon/metabolism , Parkinsonian Disorders/physiopathology , Ubiquitin-Protein Ligases/metabolism , Aged , Aged, 80 and over , Animals , Corpus Striatum/pathology , Female , Humans , Male , Mesencephalon/pathology , Middle Aged , Mutation , Parkinsonian Disorders/pathology , Phosphorylation , Rats , Rats, Sprague-Dawley , Solubility , Ubiquitin-Protein Ligases/genetics , Vacuoles/physiology , alpha-Synuclein/genetics , alpha-Synuclein/metabolism , tau Proteins/metabolismABSTRACT
Thymocyte cell death was investigated after UVA-irradiation (365 nm) of the primary thymocyte culture in vitro. To determine the mode of cell death two fluorescent DNA-binding dyes (Acridine Orange and Ethidium Bromide) were used along with flow cytometry. Thymocytes undergo apoptosis spontaneously, but a percentage of apoptotic cells was seen to increase in a dose dependent manner after thymocytes exposition to 1-100 J/m2 UVA. These doses are lower than those commonly used for apoptosis induction in other lymphoid cells. Using flow cytometry, we demonstrated that UVA-irradiation induced two different types of apoptosis. The one referred to as the "fast" apoptosis was recorded within 1-4 h following irradiation, whereas the other one, called the "delayed" apoptosis occurred within 3-24 h after irradiation. After UVA-irradiation, the activation of the former prevented the development of the latter; whereas the inhibition of delayed apoptosis brought about the induction of the fast apoptosis in thymocytes. The interrelation between the fast and delayed types of apoptosis in thymocytes can be modulated by cycloheximide, an inhibitor of protein synthesis.
