A Cre-dependent reporter mouse for quantitative real-time imaging of protein kinase A activity dynamics
(2024) Scientific Reports, 14 (1), .
Tilden, E.I.a b , Maduskar, A.a , Oldenborg, A.a , Sabatini, B.L.c , Chen, Y.a
a Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
b Ph.D. Program in Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
c Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States
Abstract
Intracellular signaling dynamics play a crucial role in cell function. Protein kinase A (PKA) is a key signaling molecule that has diverse functions, from regulating metabolism and brain activity to guiding development and cancer progression. We previously developed an optical reporter, FLIM-AKAR, that allows for quantitative imaging of PKA activity via fluorescence lifetime imaging microscopy and photometry. However, using viral infection or electroporation for the delivery of FLIM-AKAR is invasive and results in variable expression. Here, we developed a reporter mouse, FL-AK, which expresses FLIM-AKAR in a Cre-dependent manner from the ROSA26 locus. FL-AK provides robust and consistent expression of FLIM-AKAR over time. Functionally, the mouse line reports an increase in PKA activity in response to activation of both Gαs and Gαq-coupled receptors in brain slices. In vivo, FL-AK reports PKA phosphorylation in response to neuromodulator receptor activation. Thus, FL-AK provides a quantitative, robust, and flexible method to reveal the dynamics of PKA activity in diverse cell types. © The Author(s) 2024.
Funding details
National Institute of Mental HealthNIMHMH126964
National Institute on AgingNIAF30 AG084271
National Institute of Neurological Disorders and StrokeNINDSR01 NS119821
Whitehall Foundation2019-08-64
Foundation for Barnes-Jewish HospitalFBJH3770, 4642
St. Louis Children’s HospitalSLCHCDI-CORE-2015-505, CDI-CORE-2019-813
Document Type: Article
Publication Stage: Final
Source: Scopus
Brain injury drives optic glioma formation through neuron-glia signaling
(2024) Acta Neuropathologica Communications, 12 (1), .
Chatterjee, J., Koleske, J.P., Chao, A., Sauerbeck, A.D., Chen, J.-K., Qi, X., Ouyang, M., Boggs, L.G., Idate, R., Marco Y Marquez, L.I., Kummer, T.T., Gutmann, D.H.
Department of Neurology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
Abstract
Tissue injury and tumorigenesis share many cellular and molecular features, including immune cell (T cells, monocytes) infiltration and inflammatory factor (cytokines, chemokines) elaboration. Their common pathobiology raises the intriguing possibility that brain injury could create a tissue microenvironment permissive for tumor formation. Leveraging several murine models of the Neurofibromatosis type 1 (NF1) cancer predisposition syndrome and two experimental methods of brain injury, we demonstrate that both optic nerve crush and diffuse traumatic brain injury induce optic glioma (OPG) formation in mice harboring Nf1-deficient preneoplastic progenitors. We further elucidate the underlying molecular and cellular mechanisms, whereby glutamate released from damaged neurons stimulates IL-1β release by oligodendrocytes to induce microglia expression of Ccl5, a growth factor critical for Nf1-OPG formation. Interruption of this cellular circuit using glutamate receptor, IL-1β or Ccl5 inhibitors abrogates injury-induced glioma progression, thus establishing a causative relationship between injury and tumorigenesis. © The Author(s) 2024.
Author Keywords
Brain tumor; Cytokine; Microglia; Optic glioma; Optic nerve crush; Traumatic brain injury; Tumor microenvironment; Tumorigenesis
Funding details
National Institutes of HealthNIHR01-BX005204, R01-NS121612, R35-NS097211
National Eye InstituteNEIP30EY002687
National Cancer InstituteNCIP30-CA091842
National Center for Research ResourcesNCRR
Institute of Clinical and Translational SciencesICTS
Georgia Clinical and Translational Science AllianceGaCTSAUL1TR002345
Document Type: Article
Publication Stage: Final
Source: Scopus
Post-mortem changes of anisotropic mechanical properties in the porcine brain assessed by MR elastography
(2024) Brain Multiphysics, 6, art. no. 100091, .
Wang, S.a , Eckstein, K.N.a , Guertler, C.A.a , Johnson, C.L.b , Okamoto, R.J.a , McGarry, M.D.J.c , Bayly, P.V.a d
a Washington University in St. Louis, Mechanical Engineering and Material Science, United States
b University of Delaware, Biomedical Engineering, United States
c Dartmouth College, Thayer School of Engineering, United States
d Washington University in St. Louis, Biomedical Engineering, United States
Abstract
Knowledge of the mechanical properties of brain tissue in vivo is essential to understanding the mechanisms underlying traumatic brain injury (TBI) and to creating accurate computational models of TBI and neurosurgical simulation. Brain white matter, which is composed of aligned, myelinated, axonal fibers, is structurally anisotropic. White matter in vivo also exhibits mechanical anisotropy, as measured by magnetic resonance elastography (MRE), but measurements of anisotropy obtained by mechanical testing of white matter ex vivo have been inconsistent. The minipig has a gyrencephalic brain with similar white matter and gray matter proportions to humans and therefore provides a relevant model for human brain mechanics. In this study, we compare estimates of anisotropic mechanical properties of the minipig brain obtained by identical, non-invasive methods in the live (in vivo) and dead animals (in situ). To do so, we combine wave displacement fields from MRE and fiber directions derived from diffusion tensor imaging (DTI) with a finite element-based, transversely-isotropic nonlinear inversion (TI-NLI) algorithm. Maps of anisotropic mechanical properties in the minipig brain were generated for each animal alive and at specific times post-mortem. These maps show that white matter is stiffer, more dissipative, and more anisotropic than gray matter when the minipig is alive, but that these differences largely disappear post-mortem, with the exception of tensile anisotropy. Overall, brain tissue becomes stiffer, less dissipative, and less mechanically anisotropic post-mortem. These findings emphasize the importance of testing brain tissue properties in vivo. Statement of Significance: In this study, MRE and DTI in the minipig were combined to estimate, for the first time, anisotropic mechanical properties in the living brain and in the same brain after death. Significant differences were observed in the anisotropic behavior of brain tissue post-mortem. These results demonstrate the importance of measuring brain tissue properties in vivo as well as ex vivo, and provide new quantitative data for the development of computational models of brain biomechanics. © 2024 The Author(s)
Author Keywords
Anisotropy; Brain tissue stiffness; Diffusion tensor imaging; Magnetic resonance elastography; Post-mortem changes
Funding details
National Institutes of HealthNIHR01EB027577
Office of Naval ResearchONRN00014-22-1-2198
Document Type: Article
Publication Stage: Final
Source: Scopus
Investigating White Matter Neuroinflammation in Alzheimer Disease Using Diffusion-Based Neuroinflammation Imaging
(2024) Neurology, 102 (4), p. e208013.
Wang, Q., Schindler, S.E., Chen, G., Mckay, N.S., McCullough, A., Flores, S., Liu, J., Sun, Z., Wang, S., Wang, W., Hassenstab, J., Cruchaga, C., Perrin, R.J., Fagan, A.M., Morris, J.C., Wang, Y., Benzinger, T.L.S.
From the Mallinckrodt Institute of Radiology (Q.W., G.C., N.S.M., A.M., S.F., Y.W., T.L.S.B.), Knight Alzheimer Disease Research Center (Q.W., S.E.S., G.C., N.S.M., A.M., J.H., R.J.P., A.M.F., J.C.M., T.L.S.B.), Department of Neurology (S.E.S., J.H., C.C., A.M.F., J.C.M.), Department of Surgery (J.L.), Department of Biomedical Engineering (Z.S.), Department of Electrical and System Engineering (S.W., W.W., Y.W.), Department of Psychiatry (C.C.), Department of Pathology & Immunology (R.J.P.), Department of Obstetrics & Gynecology (Y.W.), and Department of Neurosurgery (T.L.S.B.), Washington University School of Medicine, St. Louis, MO
Abstract
BACKGROUND AND OBJECTIVES: Alzheimer disease (AD) is primarily associated with accumulations of amyloid plaques and tau tangles in gray matter, however, it is now acknowledged that neuroinflammation, particularly in white matter (WM), significantly contributes to the development and progression of AD. This study aims to investigate WM neuroinflammation in the continuum of AD and its association with AD pathologies and cognition using diffusion-based neuroinflammation imaging (NII). METHODS: This is a cross-sectional, single-center, retrospective evaluation conducted on an observational study of 310 older research participants who were enrolled in the Knight Alzheimer’s Disease Research Center cohort. Hindered water ratio (HR), an index of WM neuroinflammation, was quantified by a noninvasive diffusion MRI method, NII. The alterations of NII-HR were investigated at different AD stages, classified based on CSF concentrations of β-amyloid (Aβ) 42/Aβ40 for amyloid and phosphorylated tau181 (p-tau181) for tau. On the voxel and regional levels, the relationship between NII-HR and CSF markers of amyloid, tau, and neuroinflammation were examined, as well as cognition. RESULTS: This cross-sectional study included 310 participants (mean age 67.1 [±9.1] years), with 52 percent being female. Subgroups included 120 individuals (38.7%) with CSF measures of soluble triggering receptor expressed on myeloid cells 2, 80 participants (25.8%) with CSF measures of chitinase-3-like protein 1, and 110 individuals (35.5%) with longitudinal cognitive measures. The study found that cognitively normal individuals with positive CSF Aβ42/Aβ40 and p-tau181 had higher HR than healthy controls and those with positive CSF Aβ42/Aβ40 but negative p-tau181. WM tracts with elevated NII-HR in individuals with positive CSF Aβ42/Aβ40 and p-tau181 were primarily located in the posterior brain regions while those with elevated NII-HR in individuals with positive CSF Aβ42/Aβ40 and p-tau181 connected the posterior and anterior brain regions. A significant negative correlation between NII-HR and CSF Aβ42/Aβ40 was found in individuals with positive CSF Aβ42/Aβ40. Baseline NII-HR correlated with baseline cognitive composite score and predicted longitudinal cognitive decline. DISCUSSION: Those findings suggest that WM neuroinflammation undergoes alterations before the onset of AD clinical symptoms and that it interacts with amyloidosis. This highlights the potential value of noninvasive monitoring of WM neuroinflammation in AD progression and treatment.
Document Type: Article
Publication Stage: Final
Source: Scopus
Identification of direct connections between the dura and the brain
(2024) Nature, .
Smyth, L.C.D.a b , Xu, D.a b , Okar, S.V.c , Dykstra, T.a b , Rustenhoven, J.a b d e , Papadopoulos, Z.a b f , Bhasiin, K.a b , Kim, M.W.a b g , Drieu, A.a b , Mamuladze, T.a b g , Blackburn, S.a b , Gu, X.a b , Gaitán, M.I.c , Nair, G.h , Storck, S.E.a b , Du, S.a b g , White, M.A.i , Bayguinov, P.j k , Smirnov, I.a b , Dikranian, K.k , Reich, D.S.c , Kipnis, J.a b f g
a Brain Immunology and Glia (BIG) Center, Washington University in St Louis, St Louis, MO, United States
b Department of Pathology and Immunology, School of Medicine, Washington University in St Louis, St Louis, MO, United States
c Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
d Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
e Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
f Neuroscience Graduate Program, School of Medicine, Washington University in St Louis, St Louis, MO, United States
g Immunology Graduate Program, School of Medicine, Washington University in St Louis, St Louis, MO, United States
h Quantitative MRI Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
i Department of Genetics, Washington University School of Medicine, Washington University in St Louis, St Louis, MO, United States
j Washington University Center for Cellular Imaging, Washington University School of Medicine, Washington University in St Louis, St Louis, MO, United States
k Department of Neuroscience, Washington University School of Medicine, Washington University in St Louis, St Louis, MO, United States
Abstract
The arachnoid barrier delineates the border between the central nervous system and dura mater. Although the arachnoid barrier creates a partition, communication between the central nervous system and the dura mater is crucial for waste clearance and immune surveillance1,2. How the arachnoid barrier balances separation and communication is poorly understood. Here, using transcriptomic data, we developed transgenic mice to examine specific anatomical structures that function as routes across the arachnoid barrier. Bridging veins create discontinuities where they cross the arachnoid barrier, forming structures that we termed arachnoid cuff exit (ACE) points. The openings that ACE points create allow the exchange of fluids and molecules between the subarachnoid space and the dura, enabling the drainage of cerebrospinal fluid and limited entry of molecules from the dura to the subarachnoid space. In healthy human volunteers, magnetic resonance imaging tracers transit along bridging veins in a similar manner to access the subarachnoid space. Notably, in neuroinflammatory conditions such as experimental autoimmune encephalomyelitis, ACE points also enable cellular trafficking, representing a route for immune cells to directly enter the subarachnoid space from the dura mater. Collectively, our results indicate that ACE points are a critical part of the anatomy of neuroimmune communication in both mice and humans that link the central nervous system with the dura and its immunological diversity and waste clearance systems. © The Author(s), under exclusive licence to Springer Nature Limited 2024.
Funding details
National Institutes of HealthNIH
National Institute on AgingNIAAG034113, AG078106
National Institute of Neurological Disorders and StrokeNINDSNS003119
National Multiple Sclerosis SocietyNMSSFG-2208-40289
Cure Alzheimer’s FundCAF
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Performance of the Lumipulse plasma Aβ42/40 and pTau181 immunoassays in the detection of amyloid pathology
(2024) Alzheimer’s and Dementia: Diagnosis, Assessment and Disease Monitoring, 16 (1), art. no. e12545, .
Figdore, D.J.a , Wiste, H.J.b , Bornhorst, J.A.a , Bateman, R.J.c , Li, Y.c , Graff-Radford, J.d , Knopman, D.S.d , Vemuri, P.e , Lowe, V.J.e , Jr, C.R.J.e , Petersen, R.C.d , Algeciras-Schimnich, A.a
a Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
b Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, United States
c Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States
d Department of Neurology, Mayo Clinic, Rochester, MN, United States
e Department of Radiology, Mayo Clinic, Rochester, MN, United States
Abstract
INTRODUCTION: This study evaluated the performance of the Lumipulse plasma beta-amyloid (Aβ) 42/40 and pTau181 compared to other assays to detect an abnormal amyloid-positron emission tomography (PET). METHODS: Plasma samples from cognitively unimpaired (N = 179) and MCI/AD dementia (N = 36) individuals were retrospectively evaluated. Plasma Aβ42/40 and pTau181 were measured using the Lumipulse and Simoa immunoassays. An immunoprecipitation mass spectrometry (IP-MS) assay for plasma Aβ42/40 was also evaluated. Amyloid-PET status was the outcome measure. RESULTS: Lumipulse and IP-MS Aβ42/40 exhibited the highest diagnostic accuracy for detecting an abnormal amyloid-PET (areas under the curve [AUCs] of 0.81 and 0.84, respectively). The Lumipulse and Simoa pTau181 assays exhibited lower performance (AUCs of 0.74 and 0.72, respectively). The Simoa Aβ42/40 assay demonstrated the lowest diagnostic accuracy (AUC 0.57). Combining Aβ42/40 and pTau181 did not significantly improve performance over Aβ42/40 alone for Lumipulse (AUC 0.83) or over pTau181 alone for Simoa (AUC 0.71). DISCUSSION: The Lumipulse Aβ42/40 assay showed similar performance to the IP-MS Aβ42/40 assay for detection of an abnormal amyloid-PET; and both assays performed better than the two p-tau181 immunoassays. The Simoa Aβ42/Aβ40 assay was the least accurate at predicting an abnormal amyloid-PET status. Highlights: Lumipulse plasma Aβ42/Aβ40 AUC for abnormal amyloid-PET detection was 0.81. This performance was comparable to previously reported IP-MS and higher than Simoa. Performance of Alzheimer’s disease blood biomarkers varies between assays. © 2024 The Authors. Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals LLC on behalf of Alzheimer’s Association.
Author Keywords
Alzheimer’s disease blood biomarkers; amyloid beta; amyloid-PET; Aβ42/Aβ40; plasma pTau; pTau181
Funding details
National Institutes of HealthNIH
National Institute on AgingNIAR01 AG041851, R01 AG056366, R37 AG011378, RF1 AG061900, RF1 AG069052, U01 AG006786
National Cancer InstituteNCI
Mayo Clinic
Alzheimer’s Disease Research Center, Emory UniversityADRC
Novartis Pharmaceuticals CorporationNPC
GHR FoundationGHR
Bayer Schering
Document Type: Article
Publication Stage: Final
Source: Scopus
Naturalistic assessment of reaction time variability in older adults at risk for Alzheimer’s disease
(2024) Journal of the International Neuropsychological Society, .
Welhaf, M.S.a , Wilks, H.a , Aschenbrenner, A.J.b , Balota, D.A.a , Schindler, S.E.b , Benzinger, T.L.S.c , Gordon, B.A.a c , Cruchaga, C.d , Xiong, C.e , Morris, J.C.b , Hassenstab, J.a b
a Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO, United States
b Department of Neurology, Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University, School of Medicine, St. Louis, MO, United States
c Department of Radiology, Washington University, School of Medicine, St. Louis, MO, United States
d Department of Psychiatry, Washington University, School of Medicine, St. Louis, MO, United States
e Division of Biostatistics, Washington University, School of Medicine, St. Louis, MO, United States
Abstract
Objective: Maintaining attention underlies many aspects of cognition and becomes compromised early in neurodegenerative diseases like Alzheimer’s disease (AD). The consistency of maintaining attention can be measured with reaction time (RT) variability. Previous work has focused on measuring such fluctuations during in-clinic testing, but recent developments in remote, smartphone-based cognitive assessments can allow one to test if these fluctuations in attention are evident in naturalistic settings and if they are sensitive to traditional clinical and cognitive markers of AD. Method: Three hundred and seventy older adults (aged 75.8 +/- 5.8 years) completed a week of remote daily testing on the Ambulatory Research in Cognition (ARC) smartphone platform and also completed clinical, genetic, and conventional in-clinic cognitive assessments. RT variability was assessed in a brief (20-40 seconds) processing speed task using two different measures of variability, the Coefficient of Variation (CoV) and the Root Mean Squared Successive Difference (RMSSD) of RTs on correct trials. Results: Symptomatic participants showed greater variability compared to cognitively normal participants. When restricted to cognitively normal participants, APOE ϵ4 carriers exhibited greater variability than noncarriers. Both CoV and RMSSD showed significant, and similar, correlations with several in-clinic cognitive composites. Finally, both RT variability measures significantly mediated the relationship between APOE ϵ4 status and several in-clinic cognition composites. Conclusions: Attentional fluctuations over 20-40 seconds assessed in daily life, are sensitive to clinical status and genetic risk for AD. RT variability appears to be an important predictor of cognitive deficits during the preclinical disease stage. © The Author(s), 2024. Published by Cambridge University Press on behalf of International Neuropsychological Society.
Author Keywords
apolipoprotein e4; attention consistency; digital biomarkers; mobile testing; preclinical alzheimer disease
Funding details
National Institute on AgingNIAAG000030-47, K01AG071847, P01AG003991, P01AG026276, P30AG066444, R01AG057840
Document Type: Article
Publication Stage: Article in Press
Source: Scopus