Fingolimod Rescues Memory and Improves Pathological Hallmarks in the 3xTg-AD Model of Alzheimer’s Disease

Therapeutic strategies for Alzheimer’s disease (AD) have largely focused on the regulation of amyloid pathology while those targeting tau pathology, and inflammatory mechanisms are less explored. In this regard, drugs with multimodal and concurrent targeting of Aβ, tau, and inflammatory processes may offer advantages. Here, we investigate one such candidate drug in the triple transgenic 3xTg-AD mouse model of AD, namely the disease-modifying oral neuroimmunomodulatory therapeutic used in patients with multiple sclerosis, called fingolimod. In this study, administration of fingolimod was initiated after behavioral symptoms are known to emerge, at 6 months of age. Treatment continued to 12 months when behavioral tests were performed and thereafter histological and biochemical analysis was conducted on postmortem tissue. The results demonstrate that fingolimod reverses deficits in spatial working memory at 8 and 12 months of age as measured by novel object location and Morris water maze tests. Inflammation in the brain is alleviated as demonstrated by reduced Iba1-positive and CD3-positive cell number, less ramified microglial morphology, and improved cytokine profile. Finally, treatment with fingolimod was shown to reduce phosphorylated tau and APP levels in the hippocampus and cortex. These results highlight the potential of fingolimod as a multimodal therapeutic for the treatment of AD.

JOTROL, a Novel Formulation of Resveratrol, Shows Beneficial Effects in the 3xTg-AD Mouse Model

Background: Alzheimer’s disease (AD) has minimally effective treatments currently. High concentrations of resveratrol, a polyphenol antioxidant found in plants, have been reported to affect several AD-related and neuroprotective genes. To address the low bioavailability of resveratrol, we investigated a novel oral formulation of resveratrol, JOTROLTM, that has shown increased pharmacokinetic properties compared to non-formulated resveratrol in animals and in humans. Objective: We hypothesized that equivalent doses of JOTROL, compared to non-formulated resveratrol, would result in greater brain exposure to resveratrol, and more efficacious responses on AD biomarkers. Methods: For sub-chronic reversal studies, 15-month-old male triple transgenic (APPSW/PS1M146V/TauP301L; 3xTg-AD) AD mice were treated orally with vehicle or 50 mg/kg JOTROL for 36 days. For prophylactic studies, male and female 3xTg-AD mice were similarly administered vehicle, 50 mg/kg JOTROL, or 50 mg/kg resveratrol for 9 months starting at 4 months of age. A behavioral battery was run, and mRNA and protein from brain and blood were analyzed for changes in AD-related gene and protein expression. Results: JOTROL displays significantly increased bioavailability over non-formulated resveratrol. Treatment with JOTROL resulted in AD-related gene expression changes (Adam10, Bace1, Bdnf, Psen1) some of which were brain region-dependent and sex-specific, as well as changes in inflammatory gene and cytokine levels. Conclusion: JOTROL may be effective as a prophylaxis and/or treatment for AD through increased expression and/or activation of neuroprotective genes, suppression of pro-inflammatory genes, and regulation of central and peripheral cytokine levels.

Synergistic Effects of Korean Red Ginseng Extract and the Conventional Systemic Therapeutics of Atopic Dermatitis in a Murine Model

The synergistic effects of Korean Red ginseng (KRG, Panax ginseng C.A. Mey.) on conventional systemic therapeutics of atopic dermatitis (AD) have not been studied yet. To analyze the synergistic effects of KRG extract and the conventional systemic therapeutics of AD in TNCB-induced AD mouse model, we determined the change in modified scoring of index, the transepidermal water loss, the skin pathology, serum IgE, and the expression of various cytokines after combination treatment to the five-week-old NC/Nga female mice. The severity of AD was significantly decreased in the KRG + hydroxyzine (AH) group than AH group, and in the KRG + evening primrose oil (EPO) group than EPO group. A significant decrease in dermal inflammation was observed in the KRG + AH group than that in the AH group, and in the KRG + EPO group than that in the EPO group (p = 0.008), respectively. A decrease in CD1a expression was observed in the KRG + AH group when compared to the AH group (p = 0.008), and KRG + EPO group when compared to the EPO group. Compared to the CS group, the KRG + CS group showed a significant decrease in IL-17 expression. A combination of KRG and conventional systemic therapeutics can safely and effectively manage the AD.

Transcriptional signature in microglia isolated from an Alzheimers disease mouse model treated with scanning ultrasound

Rationale: Intracranial scanning ultrasound combined with intravenously injected microbubbles (SUS+MB) transiently opens the blood-brain barrier and reduces amyloid-beta (Abeta) pathology in the APP23 mouse model of Alzheimer disease (AD). This has been accomplished, at least in part, through the activation of microglial cells; however, their response to the SUS treatment is only incompletely understood. Methods: Wild-type (WT) and APP23 mice were subjected to SUS+MB, using non-SUS+MB-treated mice as sham controls. After 48 hours, the APP23 mice were injected with methoxy-XO4 to label Abeta aggregates, followed by microglial isolation into XO4+ and XO4- populations using flow cytometry. Both XO4+ and XO4- cells were subjected to RNA sequencing and their transcriptome was analyzed through a bioinformatics pipeline. Results: The transcriptomic analysis of the microglial cells revealed a clear segregation depending on genotype (AD model versus WT mice), as well as treatment (SUS+MB versus sham) and Abeta internalization (XO4+ versus XO4- microglia). Differential gene expression analysis detected 278 genes that were significantly changed by SUS+MB in the XO4+ cells (248 up/30 down) and 242 in XO- cells (225 up/17 down). Not surprisingly given previous findings of increased phagocytosis of plaques following SUS+MB, the pathway analysis highlighted that the treatment induced an enrichment in genes related to the phagosome pathway in XO4+ microglia; however, when comparing SUS+MB to sham, the analysis revealed an enrichment in genes involved in the cell cycle in both the XO4+ and XO4- microglial population. Conclusion: Our data provide a comprehensive analysis of microglia in an AD mouse model subjected to ultrasound treatment as a function of Abeta internalization, one of the defining hallmarks of AD. Several differentially expressed genes are highlighted, pointing to an ultrasound-induced activation of cell cycle mechanisms in microglial cells isolated from APP23 mice treated with SUS+MB.

Pyrroloquinoline Quinone Enhances Cognition of Neuroinflammatory Alzheimer’s Disease Mouse Model via Mitochondrial Biogenesis Regulation

Background: Mitochondrial biogenesis has been recently implicated to play an important role in Alzheimer’s disease (AD). Recently it has been reported that brains of AD patients show reduced expression in major genes and proteins such as PGC-1α involved in mitochondrial biogenesis. This led to the idea that enhancing mitochondrial biogenesis in AD, might represent a plausible strategy for AD treatment. Pyrroloquinoline quinone (PQQ) has been recently implicated in enhancing cognitive functions during aging; however, its effect on mitochondrial biogenesis in neuroinflammatory AD mouse model was not previously examined. Objective: The aim of this project was to test the cognitive enhancement effect of PQQ in a neuroinflammatory mouse model mimicking AD, and whether PQQ is able to activate mitochondrial biogenesis in brains of our AD mouse model. Methods: Neuroinflammatory AD mouse model was developed by Lipopolysaccharide (250 g kg-1 body weight, i.p) injection for 7 days, followed by daily PQQ treatment (10 mg kg-1 body weight) on days 4-7. Cognitive functions were assessed using Y-Maze, Water-Maze and object recognition tests. Neurodegeneration was evaluated using H&E. Finally, mitochondrial proteins were measured using immunohistochemistry. Results: PQQ treatment improved spatial recognition and working memory. PQQ treated mice brains showed decreased levels of neurodegeneration. Moreover, their brains showed greater amounts of both PGC-1α and the mitochondrial-membrane-bound protein cytochrome-c, indicating enhancement of mitochondrial biogenesis. Conclusion: This study demonstrates the ability of PQQ to improve memory in neuroinflammatory AD model via enhancing mitochondrial biogenesis, which may represent an alternative mechanistic approach for treating AD.

Systematic phenotyping and characterization of the 3xTg-AD mouse model of Alzheimer's Disease

Animal models of disease are valuable resources for investigating pathogenic mechanisms and potential therapeutic interventions. However, for complex disorders such as Alzheimer's disease (AD), the generation and availability of innumerous distinct animal models present unique challenges to AD researchers and hinder the success of useful therapies. Here, we conducted an in-depth analysis of the 3xTg-AD mouse model of AD across its lifespan to better inform the field of the various pathologies that appear at specific ages, and comment on drift that has occurred in the development of pathology in this line since its development 20 years ago. This modern characterization of the 3xTg-AD model includes an assessment of impairments in behavior, cognition, and long-term potentiation followed by quantification of amyloid beta (Aβ) plaque burden and neurofibrillary tau tangles, biochemical levels of Aβ, and tau protein, and neuropathological markers such as gliosis and accumulation of dystrophic neurites. We also present a novel comparison of the 3xTg-AD model with the 5xFAD model using the same deep-phenotyping characterization pipeline. The results from these analyses are freely available via the AD Knowledge Portal (https://admodelexplorer.synapse.org). Our work demonstrates the utility of a characterization pipeline that generates robust and standardized information relevant to investigating and comparing disease etiologies of current and future models of AD.