In Alzheimer disease (AD), the intracerebral accumulation of amyloid-β (Aβ) peptides is a critical yet poorly understood process. Aβ clearance via the blood-brain barrier is reduced by approximately 30% in AD patients, but the underlying mechanisms remain elusive. ABC transporters have been implicated in the regulation of Aβ levels in the brain. Using a mouse model of AD in which the animals were further genetically modified to lack specific ABC transporters, here we have shown that the transporter ABCC1 has an important role in cerebral Aβ clearance and accumulation. Deficiency of ABCC1 substantially increased cerebral Aβ levels without altering the expression of most enzymes that would favor the production of Aβ from the Aβ precursor protein.In contrast, activation of ABCC1 using thiethylperazine (a drug approved by the FDA to relieve nausea and vomiting) markedly reduced Aβ load in a mouse model of AD expressing ABCC1 but not in such mice lacking ABCC1. Thus, by altering the temporal aggregation profile of Aβ, pharmacological activation of ABC transporters could impede the neurodegenerative cascade that culminates in the dementia of AD.
In patients with Charcot–Marie–Tooth disease 1A (CMT1A), peripheral nerves display aberrant myelination during postnatal development, followed by slowly progressive demyelination and axonal loss during adult life. Here, we show that myelinating Schwann cells in a rat model of CMT1A exhibit a developmental defect that includes reduced transcription of genes required for myelin lipid biosynthesis. Consequently, lipid incorporation into myelin is reduced, leading to an overall distorted stoichiometry of myelin proteins and lipids with ultrastructural changes of the myelin sheath. Substitution of phosphatidylcholine and phosphatidylethanolamine in the diet is sufficient to overcome the myelination deficit of affected Schwann cells in vivo. This treatment rescues the number of myelinated axons in the peripheral nerves of the CMT rats and leads to a marked amelioration of neuropathic symptoms. We propose that lipid supplementation is an easily translatable potential therapeutic approach in CMT1A and possibly other dysmyelinating neuropathies.
Multiple evidence in animal models and in humans suggest a beneficial role of cold physical plasma in wound treatment. Yet, risk assessment studies are important to further foster therapeutic advancement and acceptance of cold plasma in clinics. Accordingly, we investigated the long-term side effects of repetitive plasma treatment over 14 consecutive days in a rodent full-thickness ear wound model. Subsequently, animals were housed for 350 days and sacrificed thereafter. In blood, systemic changes of the pro-inflammatory cytokines interleukin 1β and tumor necrosis factor α were absent. Similarly, tumor marker levels of α-fetoprotein and calcitonin remained unchanged. Using quantitative PCR, the expression levels of several cytokines and tumor markers in liver, lung, and skin were found to be similar in the control and treatment group as well. Likewise, histological and immunohistochemical analysis failed to detect abnormal morphological changes and the presence of tumor markers such as carcinoembryonic antigen, α-fetoprotein, or the neighbor of Punc 11. Absence of neoplastic lesions was confirmed by non-invasive imaging methods such as anatomical magnetic resonance imaging and positron emission tomography-computed tomography. Our results suggest that the beneficial effects of cold plasma in wound healing come without apparent side effects including tumor formation or chronic inflammation.
Several lines of evidence link mutations and deletions in mitochondrial DNA (mtDNA) and its maternal inheritance to neurodegenerative diseases in the elderly. Age-related mutations of mtDNA modulate tricarboxylic cycle enzyme activity, mitochondrial oxidative phosphorylation capacity and oxidative stress response. To investigate the functional relevance of specific mtDNA polymorphisms of inbred mouse strains in the proteostatic regulation of the brain, we established novel mitochondrial congenic mouse lines of Alzheimer’s disease (AD). We crossed females from inbred strains (FVB/N, AKR/J, NOD/LtJ) with C57BL/6 males for at least 10 generations to gain specific mitochondrial conplastic strains with pure C57BL/6 nuclear backgrounds. We show that specific mtDNA polymorphisms originating from the inbred strains differentially influence mitochondrial energy metabolism, ATP production and ATP-driven microglial activity, resulting in alterations of cerebral β-amyloid (Aβ) accumulation. Our findings demonstrate that mtDNA-related increases in ATP levels and subsequently in microglial activity are directly linked to decreased Aβ accumulation in vivo, implicating reduced mitochondrial function in microglia as a causative factor in the development of age-related cerebral proteopathies such as AD.
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