Microglia significantly contribute to the pathophysiology of Alzheimer's disease but an effective microglia-targeted therapeutic approach is not yet available clinically. The potassium channels Kv1.3 and Kir2.1 play important roles in regulating immune cell functions and have been implicated by in vitro studies in the 'M1-like pro-inflammatory' or 'M2-like anti-inflammatory' state of microglia, respectively. We here found that amyloid-β oligomer-induced expression of Kv1.3 and Kir2.1 in cultured primary microglia. Likewise, ex vivo microglia acutely isolated from the Alzheimer's model 5xFAD mice co-expressed Kv1.3 and Kir2.1 as well as markers traditionally associated with M1 and M2 activation suggesting that amyloid-β oligomer induces a microglial activation state that is more complex than previously thought. Using the orally available, brain penetrant small molecule Kv1.3 blocker PAP-1 as a tool, we showed that pro-inflammatory and neurotoxic microglial responses induced by amyloid-β oligomer required Kv1.3 activity in vitro and in hippocampal slices. Since we further observed that Kv1.3 was highly expressed in microglia of transgenic Alzheimer's mouse models and human Alzheimer's disease brains, we hypothesized that pharmacological Kv1.3 inhibition could mitigate the pathology induced by amyloid-β aggregates. Indeed, treating APP/PS1 transgenic mice with a 5-month oral regimen of PAP-1, starting at 9 months of age, when the animals already manifest cognitive deficits and amyloid pathology, reduced neuroinflammation, decreased cerebral amyloid load, enhanced hippocampal neuronal plasticity, and improved behavioural deficits. The observed decrease in cerebral amyloid deposition was consistent with the in vitro finding that PAP-1 enhanced amyloid-β uptake by microglia. Collectively, these results provide proof-of-concept data to advance Kv1.3 blockers to Alzheimer's disease clinical trials.
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http://dx.doi.org/10.1093/brain/awx346 | DOI Listing |
J Neuroinflammation
January 2025
Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine, Yishan Road 600, Shanghai, 200233, China.
Background: Alzheimer's disease (AD) is a prevalent neurodegenerative disorder worldwide, and microglia are thought to play a central role in neuroinflammatory events occurring in AD. Chemerin, an adipokine, has been implicated in inflammatory diseases and central nervous system disorders, yet its precise function on microglial response in AD remains unknown.
Methods: The APP/PS1 mice were treated with different dosages of chemerin-9 (30 and 60 µg/kg), a bioactive nonapeptide derived from chemerin, every other day for 8 weeks consecutively.
Nat Aging
January 2025
Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea.
The abnormal deposition of amyloid β (Aβ), produced by proteolytic cleavage events of amyloid precursor protein involving the protease γ-secretase and subsequent polymerization into amyloid plaques, plays a key role in the neuropathology of Alzheimer's disease (AD). Here we show that ErbB3 binding protein 1 (EBP1)/proliferation-associated 2G4 (PA2G4) interacts with presenilin, a catalytic subunit of γ-secretase, inhibiting Aβ production. Mice lacking forebrain Ebp1/Pa2g4 recapitulate the representative phenotypes of late-onset sporadic AD, displaying an age-dependent increase in Aβ deposition, amyloid plaques and cognitive dysfunction.
View Article and Find Full Text PDFNat Aging
January 2025
Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
Traditional approaches to studying astrocyte heterogeneity have mostly focused on analyzing static properties, failing to identify whether subtypes represent intermediate or final states of reactive astrocytes. Here we show that previously proposed neuroprotective and neurotoxic astrocytes are transitional states rather than distinct subtypes, as revealed through time-series multiomic sequencing. Neuroprotective astrocytes are an intermediate state of the transition from a nonreactive to a neurotoxic state in response to neuroinflammation, a process regulated by the mTOR signaling pathway.
View Article and Find Full Text PDFCommun Med (Lond)
January 2025
Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA.
Background: Alzheimer's disease (AD) is a major neurodegenerative disorder with significant environmental factors, including diet and lifestyle, influencing its onset and progression. Although previous studies have suggested that certain diets may reduce the incidence of AD, the underlying mechanisms remain unclear.
Method: In this post-hoc analysis of a randomized crossover study of 20 elderly adults, we investigated the effects of a modified Mediterranean ketogenic diet (MMKD) on the plasma lipidome in the context of AD biomarkers, analyzing 784 lipid species across 47 classes using a targeted lipidomics platform.
Nature
January 2025
Murdoch Children's Research Institute, Melbourne, Victoria, Australia.
Polygenic genome editing in human embryos and germ cells is predicted to become feasible in the next three decades. Several recent books and academic papers have outlined the ethical concerns raised by germline genome editing and the opportunities that it may present. To date, no attempts have been made to predict the consequences of altering specific variants associated with polygenic diseases.
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