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Background: Brain norepinephrine (NE) plays an important role in the modulation of stress response and neuroinflammation. Recent studies indicate that in Alzheimer's disease (AD), the tau neuropathology begins in the locus coeruleus (LC) which is the main source of brain NE. Therefore, we investigated the changes in brain NE system and also the immune status under basal and stress conditions in transgenic rats over-expressing the human truncated tau protein.
Methods: Brainstem catecholaminergic cell groups (LC, A1, and A2) and forebrain subcortical (nucleus basalis of Meynert), hippocampal (cornu ammonis, dentate gyrus), and neocortical areas (frontal and temporal association cortices) were analyzed for NE and interleukin 6 (IL-6) mRNA levels in unstressed rats and also in rats exposed to single or repeated immobilization. Moreover, gene expression of NE-biosynthetic enzyme, tyrosine hydroxylase (TH), and several pro- and anti-inflammatory mediators were determined in the LC.
Results: It was found that tauopathy reduced basal NE levels in forebrain areas, while the gene expression of IL-6 was increased in all selected areas at the same time. The differences between wild-type and transgenic rats in brain NE and IL-6 mRNA levels were observed in stressed animals as well. Tauopathy increased also the gene expression of TH in the LC. In addition, the LC exhibited exaggerated expression of pro- and anti-inflammatory mediators (IL-6, TNFα, inducible nitric oxide synthases 2 (iNOS2), and interleukin 10 (IL-10)) in transgenic rats suggesting that tauopathy affects also the immune background in LC. Positive correlation between NE and IL-6 mRNA levels in cornu ammonis in stressed transgenic animals indicated the reduction of anti-inflammatory effect of NE.
Conclusions: Our data thus showed that tauopathy alters the functions of LC further leading to the reduction of NE levels and exaggeration of neuroinflammation in forebrain. These findings support the assumption that tau-related dysfunction of LC activates the vicious circle perpetuating neurodegeneration leading to the development of AD.
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http://dx.doi.org/10.1186/s12974-016-0482-1 | DOI Listing |
Vet Med Int
August 2025
Department of Biology, Faculty of Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Autism spectrum disorder (ASD) is characterized by impairments in social communication and the presence of additional conditions such as heart disease. Oxidative stress has been linked to the severity of autism, suggesting a potential role for antioxidants in mitigating its effects. Aspirin, an antioxidant and anti-inflammatory drug, has shown protective effects on heart function.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
July 2025
Yunnan Provincial Academy of Science and Technology Kunming 650051, China.
This study aimed to investigate the effects of caffeoylquinic acids from Erigeron breviscapus(EBCQA) on cognitive impairment and mitochondrial dysfunction in Alzheimer's disease(AD), and to explore its underlying mechanisms. The impacts of EBCQA on paralysis, β-amyloid(Aβ) oligomerization, and mRNA expression of mitophagy-related genes [PTEN-induced putative kinase 1(PINK1) homolog-encoding gene pink-1, Parkin homolog-encoding gene pdr-1, Bcl-2 interacting coiled-coil protein 1(Beclin 1) homolog-encoding gene bec-1, microtubule-associated protein 1 light chain 3(LC3) homolog-encoding gene lgg-1, autophagic adapter protein 62(p62) homolog-encoding gene sqst-1] were examined in the AD Caenorhabditis elegans CL4176 model, along with mitochondrial functions including adenosine triphosphate(ATP) content, enzyme activities of mitochondrial respiratory chain complexes Ⅰ,Ⅲ, and Ⅳ, and mitochondrial membrane potential. Additionally, the effects of EBCQA on the green fluorescent protein(GFP)/red fluorescent protein from Discosoma sp.
View Article and Find Full Text PDFPLoS One
September 2025
Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir, Ciudad Autónoma de Buenos Aires, Argentina.
Background: One of the neuropathologic hallmarks of Alzheimer's disease (AD) is amyloid plaques composed of fibrillar amyloid beta (Aβ) that accumulate in the hippocampus and cerebral cortex. The identification of molecular changes and interactions associated with Aβ-dependent cerebral amyloidosis is a need in the field. We hypothesize that structured datasets linking proteins to differentially abundant metabolites may provide an indirect but effective means of elucidating the processes and functions in which these metabolites are involved.
View Article and Find Full Text PDFAlzheimers Res Ther
September 2025
Department of Biomedical Engineering, University of North Texas, Denton, TX, 76207, USA.
Background: Alzheimer's disease (AD) is one of the most prevalent causes of dementia, characterized by progressive memory loss and cognitive decline. Abnormal electrophysiological patterns, especially interictal epileptiform discharges (IEDs) and high-frequency oscillations (HFOs), have been observed in mouse models of AD and are suggested to contribute to cognitive dysfunction. However, comprehensive evaluations of IEDs across different brain regions are limited, and their impact on cognitive performance and neuropathology remains unclear, particularly in more complex AD models with relevant comorbidities.
View Article and Find Full Text PDFAnesth Analg
August 2025
Neuroanesthesia Laboratory, Research Division, Atlanta VA Medical Center/Emory University, Atlanta, Georgia.
Background: A clear understanding of how general anesthesia affects the brain in patients with Alzheimer disease will be crucial to optimize clinical care. We present results from laboratory investigations with a rat model used to study Alzheimer disease (TgF344-AD) to evaluate the effect of isoflurane anesthesia on the early recovery from anesthesia and postanesthesia sleep architecture in animals that exhibit mild symptoms of cognitive decline.
Methods: We used electroencephalogram (EEG) and electromyogram recordings to distinguish WAKE, NREM, and REM sleep in 8 rats from the transgenic model (AD) group and 7 age-matched control (AC) rats, 17 to 18 months of age.