Search

In patients with Alzheimer's disease (AD) and in animal models, the increased accumulation of amyloid β (Aβ) in retinal blood vessels strongly correlates with brain amyloid deposits and cognitive decline. The accumulation of Aβ in blood vessels may result from impaired transcytosis and a dysfunctional ocular glymphatic system in AD. High-dose fish oil (FO) supplementation has been shown to significantly change the expression of major facilitator superfamily domain-containing protein 2a (Mfsd2a), a key regulator of transcytosis, and Aquaporin 4 (Aqp4), an essential component of the glymphatic system in the retinas of WT mice. We examined the expression of Mfsd2a and Aqp4 in the retinas of 4-month-old 5xFAD female mice supplemented with high-dose FO for three weeks. There was a significant increase in Mfsd2a expression in 5xFAD retinas supplemented with FO compared to control 5xFAD mice. Additionally, the increase in Aqp4 expression observed in 4-month-old 5xFAD retinas, indicative of an impaired glymphatic system, was significantly decreased. Simultaneously, Aβ accumulation in 5xFAD retinal blood vessels was reduced following FO supplementation. These findings suggest that high-dose FO supplementation could serve as an adjunct in developing new treatments aimed at improving the regulation of transcytosis or the function of the glymphatic system in the AD retina. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the leading cause of mortality, disability, and long‐term care burden in the United States, with women comprising the majority of AD diagnoses. While AD‐related dementia is associated with tau and amyloid beta accumulation, concurrent derangements in cerebral blood flow have been observed alongside these proteinopathies in humans and rodent models. The homeostatic production of nitric oxide synthases (NOS) becomes uncoupled in AD which leads to decreased NO‐mediated vasodilation and oxidative stress via the production of peroxynitrite (ONOO−∙) superoxide species. Here, we investigate the role of the novel protein arginine methyltransferase 4 (PRMT4) enzyme function and its downstream product asymmetric dimethyl arginine (ADMA) as it relates to NOS dysregulation and cerebral blood flow in AD. ADMA (type‐1 PRMT product) has been shown to bind NOS as a noncanonic ligand causing enzymatic dysfunction. Our results from RT‐qPCR and protein analyses suggest that aged (9−12 months) female mice bearing tau‐ and amyloid beta‐producing transgenic mutations (3xTg‐AD) express higher levels of PRMT4 in the hippocampus when compared to age‐ and sex‐matched C57BL6/J mice. In addition, we performed studies to quantify the expression and activity of different NOS isoforms. Furthermore, laser speckle contrast imaging analysis was indicative that 3xTg‐AD mice have dysfunctional NOS activity, resulting in reduced production of NO metabolites, enhanced production of free‐radical ONOO−, and decreased cerebral blood flow. Notably, the aforementioned phenomena can be reversed via pharmacologic PRMT4 inhibition. Together, these findings implicate the potential importance of PRMT4 signaling in the pathogenesis of Alzheimer's‐related cerebrovascular derangement. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Photobiomodulation Inhibits Ischemia-Induced Brain Endothelial Senescence via Endothelial Nitric Oxide Synthase" published in the journal Antioxidants. The correction addresses a mistake in Figure 7A of the original publication, which displayed incorrect immunofluorescence images. The corrected figure is provided, and the authors assure that the scientific conclusions remain unaffected. The correction was approved by the Academic Editor, and the original publication has been updated. [Extracted from the article]

Background: The most currently used general anaesthetics are potent potentiators of γ-aminobutyric acid A (GABAA) receptors and are invariably neurotoxic during the early stages of brain development in preclinical animal models. As causality between GABAA potentiation and anaesthetic-induced developmental neurotoxicity has not been established, the question remains whether GABAergic activity is crucial for promoting/enhancing neurotoxicity. Using the neurosteroid analogue, (3α,5α)-3-hydroxy-13,24-cyclo-18,21-dinorchol-22-en-24-ol (CDNC24), which potentiates recombinant GABAA receptors, we examined whether this potentiation is the driving force in inducing neurotoxicity during development.Methods: The neurotoxic potential of CDNC24 was examined vis-à-vis propofol (2,6-diisopropylphenol) and alphaxalone (5α-pregnan-3α-ol-11,20-dione) at the peak of rat synaptogenesis. In addition to the morphological neurotoxicity studies of the subiculum and medial prefrontal cortex (mPFC), we assessed the extra-, pre-, and postsynaptic effects of these agents on GABAergic neurotransmission in acute subicular slices from rat pups.Results: CDNC24, like alphaxalone and propofol, caused dose-dependent hypnosis in vivo, with a higher therapeutic index. CDNC24 and alphaxalone, unlike propofol, did not cause developmental neuroapoptosis in the subiculum and mPFC. Propofol potentiated post- and extrasynaptic GABAA currents as evidenced by increased spontaneous inhibitory postsynaptic current (sIPSC) decay time and prominent tonic currents, respectively. CDNC24 and alphaxalone had a similar postsynaptic effect, but also displayed a strong presynaptic effect as evidenced by decreased frequency of sIPSCs and induced moderate tonic currents.Conclusions: The lack of neurotoxicity of CDNC24 and alphaxalone may be at least partly related to suppression of presynaptic GABA release in the developing brain. [ABSTRACT FROM AUTHOR]

Pain-sensing sensory neurons of the dorsal root ganglion (DRG) can become sensitized or hyperexcitable in response to surgically induced peripheral tissue injury. We investigated the potential role and molecular mechanisms of nociceptive ion channel dysregulation in acute pain conditions such as those resulting from skin and soft tissue incision. We used selective pharmacology, electrophysiology, and mouse genetics to link increased current densities arising from the CaV3.2 isoform of T-type calcium channels (T-channels) to nociceptive sensitization using a clinically relevant rodent model of skin and deep tissue incision. Furthermore, knockdown of the CaV3.2-targeting deubiquitinating enzyme USP5 or disruption of USP5 binding to CaV3.2 channels in peripheral nociceptors resulted in a robust antihyperalgesic effect in vivo and substantial T-current reduction in vitro. Our study provides mechanistic insight into the role of plasticity in CaV3.2 channel activity after surgical incision and identifies potential targets for perioperative pain that may greatly decrease the need for narcotics and potential for drug abuse. [ABSTRACT FROM AUTHOR]

Recent data have implicated voltage-gated calcium channels in the regulation of the excitability of neurons within the mesolimbic reward system. While the attention of most research has centered on high voltage L-type calcium channel activity, the presence and role of the low voltage-gated T-type calcium channel (T-channels) has not been well explored. Hence, we investigated T-channel properties in the neurons of the ventral tegmental area (VTA) utilizing wild-type (WT) rats and mice, Ca V 3.1 knock-out (KO) mice, and TH-eGFP knock-in (KI) rats in acute horizontal brain slices of adolescent animals. In voltage-clamp experiments, we first assessed T-channel activity in WT rats with characteristic properties of voltage-dependent activation and inactivation, as well as characteristic crisscrossing patterns of macroscopic current kinetics. T-current kinetics were similar in WT mice and WT rats but T-currents were abolished in Ca V 3.1 KO mice. In ensuing current-clamp experiments, we observed the presence of hyperpolarization-induced rebound burst firing in a subset of neurons in WT rats, as well as dopaminergic and non-dopaminergic neurons in TH-eGFP KI rats. Following the application of a pan-selective T-channel blocker TTA-P2, rebound bursting was significantly inhibited in all tested cells. In a behavioral assessment, the acute locomotor increase induced by a MK-801 (Dizocilpine) injection in WT mice was abolished in Ca V 3.1 KO mice, suggesting a tangible role for 3.1 T-type channels in drug response. We conclude that pharmacological targeting of Ca V 3.1 isoform of T-channels may be a novel approach for the treatment of disorders of mesolimbic reward system., (Published by Elsevier Ltd.)