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1.
bioRxiv ; 2024 Jun 02.
Article in English | MEDLINE | ID: mdl-38854047

ABSTRACT

High resolution retinal imaging paired with intravitreal injection of a viral vector coding for the calcium indicator GCaMP has enabled visualization of activity dependent calcium changes in retinal ganglion cells (RGCs) at single cell resolution in the living eye. The inner limiting membrane (ILM) is a barrier for viral vectors, restricting transduction to a ring of RGCs serving the fovea in both humans and non-human primates (NHP). We evaluate peeling the ILM prior to intravitreal injection as a strategy to expand calcium imaging beyond the fovea in the NHP eye in vivo. Five Macaca fascicularis eyes (age 3-10y; n=3 individuals; 2M, 1F) underwent vitrectomy and 5 to 6-disc diameter ILM peel centered on the fovea prior to intravitreal delivery of 7m8:SNCG:GCaMP8s. Calcium responses from RGCs were recorded using a fluorescence adaptive optics scanning laser ophthalmoscope. In all eyes GCaMP was expressed throughout the peeled area, representing a mean 8-fold enlargement in area of expression relative to a control eye. Calcium recordings were obtained up to 11 degrees from the foveal center. RGC responses were comparable to the fellow control eye and showed no significant decrease over the 6 months post ILM peel, suggesting that RGC function was not compromised by the surgical procedure. In addition, we demonstrate that activity can be recorded directly from the retinal nerve fiber layer. This approach will be valuable for a range of applications in visual neuroscience including pre-clinical evaluation of retinal function, detecting vision loss, and assessing the impact of therapeutic interventions.

2.
Alzheimers Dement ; 20(4): 2794-2816, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38426371

ABSTRACT

INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative disorder with multifactorial etiology, including genetic factors that play a significant role in disease risk and resilience. However, the role of genetic diversity in preclinical AD studies has received limited attention. METHODS: We crossed five Collaborative Cross strains with 5xFAD C57BL/6J female mice to generate F1 mice with and without the 5xFAD transgene. Amyloid plaque pathology, microglial and astrocytic responses, neurofilament light chain levels, and gene expression were assessed at various ages. RESULTS: Genetic diversity significantly impacts AD-related pathology. Hybrid strains showed resistance to amyloid plaque formation and neuronal damage. Transcriptome diversity was maintained across ages and sexes, with observable strain-specific variations in AD-related phenotypes. Comparative gene expression analysis indicated correlations between mouse strains and human AD. DISCUSSION: Increasing genetic diversity promotes resilience to AD-related pathogenesis, relative to an inbred C57BL/6J background, reinforcing the importance of genetic diversity in uncovering resilience in the development of AD. HIGHLIGHTS: Genetic diversity's impact on AD in mice was explored. Diverse F1 mouse strains were used for AD study, via the Collaborative Cross. Strain-specific variations in AD pathology, glia, and transcription were found. Strains resilient to plaque formation and plasma neurofilament light chain (NfL) increases were identified. Correlations with human AD transcriptomics were observed.


Subject(s)
Alzheimer Disease , Resilience, Psychological , Mice , Humans , Female , Animals , Alzheimer Disease/pathology , Plaque, Amyloid/pathology , Mice, Inbred C57BL , Microglia/metabolism , Genetic Variation/genetics , Disease Models, Animal , Mice, Transgenic , Amyloid beta-Peptides/metabolism
3.
Alzheimers Dement ; 2024 Mar 20.
Article in English | MEDLINE | ID: mdl-38506634

ABSTRACT

BACKGROUND: Variants in ABCA7, a member of the ABC transporter superfamily, have been associated with increased risk for developing late onset Alzheimer's disease (LOAD). METHODS: CRISPR-Cas9 was used to generate an Abca7V1613M variant in mice, modeling the homologous human ABCA7V1599M variant, and extensive characterization was performed. RESULTS: Abca7V1613M microglia show differential gene expression profiles upon lipopolysaccharide challenge and increased phagocytic capacity. Homozygous Abca7V1613M mice display elevated circulating cholesterol and altered brain lipid composition. When crossed with 5xFAD mice, homozygous Abca7V1613M mice display fewer Thioflavin S-positive plaques, decreased amyloid beta (Aß) peptides, and altered amyloid precursor protein processing and trafficking. They also exhibit reduced Aß-associated inflammation, gliosis, and neuronal damage. DISCUSSION: Overall, homozygosity for the Abca7V1613M variant influences phagocytosis, response to inflammation, lipid metabolism, Aß pathology, and neuronal damage in mice. This variant may confer a gain of function and offer a protective effect against Alzheimer's disease-related pathology. HIGHLIGHTS: ABCA7 recognized as a top 10 risk gene for developing Alzheimer's disease. Loss of function mutations result in increased risk for LOAD. V1613M variant reduces amyloid beta plaque burden in 5xFAD mice. V1613M variant modulates APP processing and trafficking in 5xFAD mice. V1613M variant reduces amyloid beta-associated damage in 5xFAD mice.

4.
Alzheimers Dement ; 20(4): 2922-2942, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38460121

ABSTRACT

INTRODUCTION: The BIN1 coding variant rs138047593 (K358R) is linked to Late-Onset Alzheimer's Disease (LOAD) via targeted exome sequencing. METHODS: To elucidate the functional consequences of this rare coding variant on brain amyloidosis and neuroinflammation, we generated BIN1K358R knock-in mice using CRISPR/Cas9 technology. These mice were subsequently bred with 5xFAD transgenic mice, which serve as a model for Alzheimer's pathology. RESULTS: The presence of the BIN1K358R variant leads to increased cerebral amyloid deposition, with a dampened response of astrocytes and oligodendrocytes, but not microglia, at both the cellular and transcriptional levels. This correlates with decreased neurofilament light chain in both plasma and brain tissue. Synaptic densities are significantly increased in both wild-type and 5xFAD backgrounds homozygous for the BIN1K358R variant. DISCUSSION: The BIN1 K358R variant modulates amyloid pathology in 5xFAD mice, attenuates the astrocytic and oligodendrocytic responses to amyloid plaques, decreases damage markers, and elevates synaptic densities. HIGHLIGHTS: BIN1 rs138047593 (K358R) coding variant is associated with increased risk of LOAD. BIN1 K358R variant increases amyloid plaque load in 12-month-old 5xFAD mice. BIN1 K358R variant dampens astrocytic and oligodendrocytic response to plaques. BIN1 K358R variant decreases neuronal damage in 5xFAD mice. BIN1 K358R upregulates synaptic densities and modulates synaptic transmission.


Subject(s)
Alzheimer Disease , Animals , Mice , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloid beta-Peptides , Disease Models, Animal , Mice, Transgenic , Neuroglia/pathology , Plaque, Amyloid/pathology , Humans
5.
Mol Neurodegener ; 18(1): 12, 2023 02 17.
Article in English | MEDLINE | ID: mdl-36803190

ABSTRACT

BACKGROUND: The TREM2 R47H variant is one of the strongest genetic risk factors for late-onset Alzheimer's Disease (AD). Unfortunately, many current Trem2 R47H mouse models are associated with cryptic mRNA splicing of the mutant allele that produces a confounding reduction in protein product. To overcome this issue, we developed the Trem2R47H NSS (Normal Splice Site) mouse model in which the Trem2 allele is expressed at a similar level to the wild-type Trem2 allele without evidence of cryptic splicing products. METHODS: Trem2R47H NSS mice were treated with the demyelinating agent cuprizone, or crossed with the 5xFAD mouse model of amyloidosis, to explore the impact of the TREM2 R47H variant on inflammatory responses to demyelination, plaque development, and the brain's response to plaques. RESULTS: Trem2R47H NSS mice display an appropriate inflammatory response to cuprizone challenge, and do not recapitulate the null allele in terms of impeded inflammatory responses to demyelination. Utilizing the 5xFAD mouse model, we report age- and disease-dependent changes in Trem2R47H NSS mice in response to development of AD-like pathology. At an early (4-month-old) disease stage, hemizygous 5xFAD/homozygous Trem2R47H NSS (5xFAD/Trem2R47H NSS) mice have reduced size and number of microglia that display impaired interaction with plaques compared to microglia in age-matched 5xFAD hemizygous controls. This is associated with a suppressed inflammatory response but increased dystrophic neurites and axonal damage as measured by plasma neurofilament light chain (NfL) level. Homozygosity for Trem2R47H NSS suppressed LTP deficits and loss of presynaptic puncta caused by the 5xFAD transgene array in 4-month-old mice. At a more advanced (12-month-old) disease stage 5xFAD/Trem2R47H NSS mice no longer display impaired plaque-microglia interaction or suppressed inflammatory gene expression, although NfL levels remain elevated, and a unique interferon-related gene expression signature is seen. Twelve-month old Trem2R47H NSS mice also display LTP deficits and postsynaptic loss. CONCLUSIONS: The Trem2R47H NSS mouse is a valuable model that can be used to investigate age-dependent effects of the AD-risk R47H mutation on TREM2 and microglial function including its effects on plaque development, microglial-plaque interaction, production of a unique interferon signature and associated tissue damage.


Subject(s)
Alzheimer Disease , Demyelinating Diseases , Mice , Animals , Alzheimer Disease/metabolism , Cuprizone/metabolism , RNA Splicing , Mutation , Plaque, Amyloid/pathology , Disease Models, Animal , Demyelinating Diseases/metabolism , Demyelinating Diseases/pathology , Microglia/metabolism , Brain/metabolism , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Receptors, Immunologic/genetics , Receptors, Immunologic/metabolism
6.
Clin Pract Cases Emerg Med ; 4(4): 671-674, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33217305

ABSTRACT

INTRODUCTION: Lyme disease typically presents with viral-like symptoms and a pathognomonic rash. With disease progression, symptoms of nervous system involvement usually include facial nerve palsy and meningitis, but other atypical neurologic manifestations have less commonly been documented. CASE REPORT: A six-year-old male presented with prolonged fevers, rash, headache, and non-specific neurologic symptoms. The diagnosis of neuroborreliosis with meningitis and polyradiculitis was confirmed with laboratory evaluation and lumbar puncture. CONCLUSION: Neuroborreliosis is a disseminated form of Lyme disease. While meningitis is a common sign, the presentation of polyradiculitis in children is rare and can lead to misdiagnosis and delay in treatment.

7.
Cureus ; 12(8): e9848, 2020 Aug 18.
Article in English | MEDLINE | ID: mdl-32953355

ABSTRACT

Background Podcasts and their use in medical education, particularly emergency medicine (EM), are growing and becoming more popular. Many podcasts focus on EM, but the number of podcasts on each EM subspecialty remains unknown. Therefore, the goal of this study was to ascertain the number of podcasts available by EM subspecialty and collect the basic characteristics of each podcast. Methods We conducted a Google-based, investigational study of EM podcasts by subspecialty from July 2019 to January 2020. Search terms included "podcasts in ____", where the EM subspecialties of Toxicology, Ultrasound, Wilderness Medicine, Emergency Medicine Services, Medical Education, and Simulation were inserted to identify podcasts. Results  Emergency Medical Services (EMS) and Medical Education subspecialties have the most active podcasts. Toxicology and EMS have the most inactive podcasts, while Medical Education and Simulation were the only subspecialties found to not have any identified inactive podcasts. Conclusions The use of podcasts in EM has been increasing overall, but physicians in specific subspecialties, such as EMS and Medical Education, have access to a larger number of podcasts specific to their subspecialty than others. There is an opportunity for experts in Toxicology, Simulation, and Ultrasound to create podcast content.

9.
J Calif Dent Assoc ; 39(9): 631-7, 2011 Sep.
Article in English | MEDLINE | ID: mdl-22034797

ABSTRACT

Sjögren's syndrome is a common autoimmune disorder characterized by dry mouth and dry eyes. Symptoms and signs are chronic and can be severe. The diagnosis of Sjögren's syndrome can be confusing and time-consuming. The management can also be a significant challenge for the clinicians. However, recent genomic and proteomic developments are unlocking the mystery of the disease process as well as contributing to our ability to define, diagnose, and develop new treatment modalities for patients with this complex disorder.


Subject(s)
Sjogren's Syndrome/physiopathology , Autoimmune Diseases/physiopathology , Humans , Sjogren's Syndrome/classification , Sjogren's Syndrome/diagnosis , Sjogren's Syndrome/therapy , Xerophthalmia/physiopathology , Xerostomia/physiopathology
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