Alzheimer Disease in a Mouse Model: MR Imaging–guided Focused Ultrasound Targeted to the Hippocampus Opens the Blood-Brain Barrier and Improves Pathologic Abnormalities and Behavior

Burgess, Alison; Dubey, Sonam; Yeung, Sharon; Hough, Olivia; Eterman, Naomi; Aubert, Isabelle; Hynynen, Kullervo

doi:10.1148/radiol.14140245

Cited by 247 publications

(279 citation statements)

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“…Within 2 h after pFUS+MB we detected a significant doubling of IL1β that would activate microglia and clear βAPP plaques from the hippocampus (87). Moreover, the presence of inflammatory cytokines may contribute to the expression of BDNF, EPO, and VEGF in our study and could explain the enhanced neurogenesis observed in AD models (38,40). Opening of the BBB was associated with the influx of serum products that represent damage signals to microglia, resulting in activation (59).…”

Section: Discussionmentioning

confidence: 48%

“…It has been reported that exposure of the hippocampus to pFUS+MB in AD models revealed microglial phagocytosing beta amyloid precursor protein (βAPP) and increased neurogenesis based on bromo-deoxyuridine uptake or double-cortin staining of proliferating cells (20,38,40,86). Neurobehavioral testing of these treated mice demonstrated improvements in memory function following multiple pFUS+MB exposures.…”

Section: Discussionmentioning

confidence: 99%

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Disrupting the blood–brain barrier by focused ultrasound induces sterile inflammation

Kovács

Kim

Jikaria

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

368

388

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MRI-guided pulsed focused ultrasound (pFUS) combined with systemic infusion of ultrasound contrast agent microbubbles (MB) causes localized blood-brain barrier (BBB) disruption that is currently being advocated for increasing drug or gene delivery in neurological diseases. The mechanical acoustic cavitation effects of opening the BBB by low-intensity pFUS+MB, as evidenced by contrast-enhanced MRI, resulted in an immediate damage-associated molecular pattern (DAMP) response including elevations in heat-shock protein 70, IL-1, IL-18, and TNFα indicative of a sterile inflammatory response (SIR) in the parenchyma. Concurrent with DAMP presentation, significant elevations in proinflammatory, antiinflammatory, and trophic factors along with neurotrophic and neurogenesis factors were detected; these elevations lasted 24 h. Transcriptomic analysis of sonicated brain supported the proteomic findings and indicated that the SIR was facilitated through the induction of the NFκB pathway. Histological evaluation demonstrated increased albumin in the parenchyma that cleared by 24 h along with TUNEL + neurons, activated astrocytes, microglia, and increased cell adhesion molecules in the vasculature. Infusion of fluorescent beads 3 d before pFUS+MB revealed the infiltration of CD68 + macrophages at 6 d postsonication, as is consistent with an innate immune response. pFUS+MB is being considered as part of a noninvasive adjuvant treatment for malignancy or neurodegenerative diseases. These results demonstrate that pFUS+MB induces an SIR compatible with ischemia or mild traumatic brain injury. Further investigation will be required before this approach can be widely implemented in clinical trials.pulsed focused ultrasound | microbubbles | blood-brain barrier | sterile inflammation | magnetic resonance imaging T he temporal proteomic profile in response to blood-brain barrier disruption (BBBD) consists of molecular features that are common across noninfectious insults such as ischemia, trauma, or autoimmune diseases (1-7). The main purpose of the bloodbrain barrier (BBB) is to maintain homeostasis, preventing the passive crossing of cells and molecules that could induce inflammation or damage to cells. The BBB consists of specialized endothelial cells connected through various tight junction proteins (TJP), astrocyte endplates, and a basement membrane. These components form part of the neurovascular unit (NVU) that is comprised of vessels, pericytes, microglia, astrocytes, and neurons along with the extracellular matrix (1,3,4,8). BBBD secondary to ischemia or trauma leads to increases in endothelial caveolae and down-regulation of TJP, transcytosis of plasma proteins (i.e., albumin), and vasogenic edema (1,6,(8)(9)(10)(11). The presence of albumin in the parenchyma following BBBD can activate astrocytes and microglia and induce the production of cytokines, chemokines, and trophic factors (CCTFs) and cell adhesion molecules (CAMs) as observed with a sterile inflammatory response (SIR) to injury (12-15). The release of CCTFs and inte...

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Section: Discussionmentioning

confidence: 48%

Section: Discussionmentioning

confidence: 99%

Disrupting the blood–brain barrier by focused ultrasound induces sterile inflammation

Kovács

Kim

Jikaria

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

368

388

View full text Add to dashboard Cite

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“…Further support for the potential influence of peripheral IgG in the clearance of Aβ pathology has recently been suggested by a group that used transcranial focused ultrasound to transiently open the BBB. Following ultrasound, this group observed a significant reduction in amyloid pathology, which they suggested might be due to increased infiltration of endogenous IgG into the brain (42,43).…”

Section: Discussionmentioning

confidence: 87%

The adaptive immune system restrains Alzheimer’s disease pathogenesis by modulating microglial function

Marsh

Abud

Lakatos

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

344

287

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The innate immune system is strongly implicated in the pathogenesis of Alzheimer's disease (AD). In contrast, the role of adaptive immunity in AD remains largely unknown. However, numerous clinical trials are testing vaccination strategies for AD, suggesting that T and B cells play a pivotal role in this disease. To test the hypothesis that adaptive immunity influences AD pathogenesis, we generated an immune-deficient AD mouse model that lacks T, B, and natural killer (NK) cells. The resulting "Rag-5xfAD" mice exhibit a greater than twofold increase in β-amyloid (Aβ) pathology. Gene expression analysis of the brain implicates altered innate and adaptive immune pathways, including changes in cytokine/chemokine signaling and decreased Ig-mediated processes. Neuroinflammation is also greatly exacerbated in Rag-5xfAD mice as indicated by a shift in microglial phenotype, increased cytokine production, and reduced phagocytic capacity. In contrast, immune-intact 5xfAD mice exhibit elevated levels of nonamyloid reactive IgGs in association with microglia, and treatment of Rag-5xfAD mice or microglial cells with preimmune IgG enhances Aβ clearance. Last, we performed bone marrow transplantation studies in Rag-5xfAD mice, revealing that replacement of these missing adaptive immune populations can dramatically reduce AD pathology. Taken together, these data strongly suggest that adaptive immune cell populations play an important role in restraining AD pathology. In contrast, depletion of B cells and their appropriate activation by T cells leads to a loss of adaptiveinnate immunity cross talk and accelerated disease progression.is the leading cause of age-related neurodegeneration, affecting over 5.2 million people in the United States alone (1). Pathologically, AD is characterized by two hallmark protein aggregates, amyloid-β (Aβ) plaques and neurofibrillary tangles, that are accompanied by neuroinflammation, including microgliosis, elevated cytokine production, and activation of complement pathways (2-5). Initially, microglia respond to and surround plaques, degrading Aβ by phagocytosis (for review, see refs. 6-8). However, chronic activation of these cells shift microglia to a more proinflammatory and less phagocytic state (9, 10). Although much of the data implicating microglia in AD has come from neuropathological investigation, recent genome-wide association studies have provided the first genetic evidence (to our knowledge) linking microglia dysfunction to AD, with the discovery of risk polymorphisms in several immune system genes: CR1, TREM2, CD33, HLA-DRB5, MS4A6A, and ABCA7 (8,(11)(12)(13)(14)(15).In contrast to the field's increasing understanding of the role of innate immunity in AD, comparatively little is known about whether the adaptive immune system might also influence AD. Those studies that have examined these peripheral populations have largely focused on questions about their potential as biomarkers or their role in active Aβ immunization (3, 16). However, the adaptive and innate immune systems rarely fu...

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“…After transduction and expression of chemogenetic receptors in a genetically defined subset of cells at the FUS-targeted site, neuromodulation is conveniently controlled using an orally bioavailable drug. The fact that a single FUS-BBBO session is required should also minimize the potential for non-specific cellular-level effects seen after multiple FUS-BBBO treatments 56,57 .…”

Section: Discussionmentioning

confidence: 99%

Acoustically targeted chemogenetics for the non-invasive control of neural circuits

et al. 2018

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Neurological and psychiatric diseases often involve the dysfunction of specific neural circuits in particular regions of the brain. Existing treatments, including drugs and implantable brain stimulators, aim to modulate the activity of these circuits, but are typically not cell type-specific, lack spatial targeting or require invasive procedures. Here, we introduce an approach to modulating neural circuits noninvasively with spatial, cell-type and temporal specificity. This approach, called acoustically targeted chemogenetics, or ATAC, uses transient ultrasonic opening of the blood brain barrier to transduce neurons at specific locations in the brain with virally-encoded engineered G-protein-coupled receptors, which subsequently respond to systemically administered bio-inert compounds to activate or inhibit the activity of these neurons. We demonstrate this concept in mice by using ATAC to noninvasively modify and subsequently activate or inhibit excitatory neurons within the hippocampus, showing that this enables pharmacological control of memory formation. This technology allows a brief, noninvasive procedure to make one or more specific brain regions capable of being selectively modulated using orally bioavailable compounds, thereby overcoming some of the key limitations of conventional brain therapies.

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Alzheimer Disease in a Mouse Model: MR Imaging–guided Focused Ultrasound Targeted to the Hippocampus Opens the Blood-Brain Barrier and Improves Pathologic Abnormalities and Behavior

Cited by 247 publications

References 33 publications

Disrupting the blood–brain barrier by focused ultrasound induces sterile inflammation

Disrupting the blood–brain barrier by focused ultrasound induces sterile inflammation

The adaptive immune system restrains Alzheimer’s disease pathogenesis by modulating microglial function

Acoustically targeted chemogenetics for the non-invasive control of neural circuits

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