Pulmonary B Lymphocytes Ameliorate Alzheimer's Disease-Like Neuropathology

Author(s):  
Weixi Feng ◽  
Yanli Zhang ◽  
Tianqi Wang ◽  
Qian Li ◽  
Ze Wang ◽  
...  

Abstract Increasing evidences reveal that the peripheral immune system is involved in the pathogenesis of Alzheimer's disease (AD). Here, we report that pulmonary B lymphocytes mitigate beta-Amyloid (Aβ) pathology in 5xFAD mice. The proportion of B cells, rather than T cells, increases within the brain, meningeal and lung tissues in 3-month-old 5xFAD mice. Deletion of mature B cells aggravates Aβ load and memory deficits of 5xFAD mice. Mechanistically, pulmonary B cells can migrate to the brain parenchyma and produce interleukin-35, which inhibits neuronal β-site APP-cleaving enzyme 1 expression, and subsequently reduces the production of Aβ. In turn, pulmonary B cell proliferation is associated with activation of the toll-like receptor/nuclear factor kappa-B pathway through elevated Aβ that is drained from the brain parenchyma to the lungs via meningeal lymphatics. Furthermore, promoting pulmonary B cell proliferation via overexpression of B-cell-activating factor ameliorates brain Aβ load and improves cognitive functions of 10-month-old 5xFAD mice. Together, these results highlight the lungs as both immune targets and effector organs in Aβ pathogenesis. Pulmonary B cells could serve as a potential target against AD.

2020 ◽  
Author(s):  
Weixi Feng ◽  
Yanli Zhang ◽  
Tianqi Wang ◽  
Ze Wang ◽  
Yan Chen ◽  
...  

Increasing evidence shows that the peripheral immune system is involved in the pathogenesis of Alzheimer’s disease (AD). Here, we report that pulmonary B cells mitigate beta-Amyloid (Aβ) pathology in 5xFAD mice. The proportion of B cells rather than T cells increases in brain, meningeal and lung tissues in 3-month-old 5xFAD mice. Deletion of B cells aggravates Aβ load and memory deficits of 5xFAD mice. Mechanimsly, pulmonary B cells can migrate to the brain parenchyma and produce interleukin-35 that inhibits neuronal β-site APP-cleaving enzyme 1 expression, subsequently reducing the production of Aβ. In turn, proliferation of pulmonary B cells is associated with activation of toll-like receptor/nuclear factor kappa-B pathway by elevated Aβ that is drained from the brain parenchyma to the lungs via meningeal lymphatics. Furthermore, promoting pulmonary B cell proliferation via overexpression of B-cell-activating factor ameliorates brain Aβ load and improves cognitive functions of 10-month-old 5xFAD mice. Together, these results highlight the lungs as both immune targets and effector organs in Aβ pathogenesis. Pulmonary B cells might be a potential target against AD.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ki Kim ◽  
Xin Wang ◽  
Emeline Ragonnaud ◽  
Monica Bodogai ◽  
Tomer Illouz ◽  
...  

AbstractThe function of B cells in Alzheimer’s disease (AD) is not fully understood. While immunoglobulins that target amyloid beta (Aβ) may interfere with plaque formation and hence progression of the disease, B cells may contribute beyond merely producing immunoglobulins. Here we show that AD is associated with accumulation of activated B cells in circulation, and with infiltration of B cells into the brain parenchyma, resulting in immunoglobulin deposits around Aβ plaques. Using three different murine transgenic models, we provide counterintuitive evidence that the AD progression requires B cells. Despite expression of the AD-fostering transgenes, the loss of B cells alone is sufficient to reduce Aβ plaque burden and disease-associated microglia. It reverses behavioral and memory deficits and restores TGFβ+ microglia, respectively. Moreover, therapeutic depletion of B cells at the onset of the disease retards AD progression in mice, suggesting that targeting B cells may also benefit AD patients.


Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 957
Author(s):  
Brad T. Casali ◽  
Erin G. Reed-Geaghan

Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer’s disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.


2020 ◽  
Vol 6 (31) ◽  
pp. eaba0466 ◽  
Author(s):  
Chun Chen ◽  
Eun Hee Ahn ◽  
Seong Su Kang ◽  
Xia Liu ◽  
Ashfaqul Alam ◽  
...  

The gut-brain axis is bidirectional, and gut microbiota influence brain disorders including Alzheimer’s disease (AD). CCAAT/enhancer binding protein β/asparagine endopeptidase (C/EBPβ/AEP) signaling spatiotemporally mediates AD pathologies in the brain via cleaving both β-amyloid precursor protein and Tau. We show that gut dysbiosis occurs in 5xFAD mice, and is associated with escalation of the C/EBPβ/AEP pathway in the gut with age. Unlike that of aged wild-type mice, the microbiota of aged 3xTg mice accelerate AD pathology in young 3xTg mice, accompanied by active C/EBPβ/AEP signaling in the brain. Antibiotic treatment diminishes this signaling and attenuates amyloidogenic processes in 5xFAD, improving cognitive functions. The prebiotic R13 inhibits this pathway and suppresses amyloid aggregates in the gut. R13-induced Lactobacillus salivarius antagonizes the C/EBPβ/AEP axis, mitigating gut leakage and oxidative stress. Our findings support the hypothesis that C/EBPβ/AEP signaling is activated by gut dysbiosis, implicated in AD pathologies in the gut.


Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 377
Author(s):  
Dina Medina-Vera ◽  
Cristina Rosell-Valle ◽  
Antonio J. López-Gambero ◽  
Juan A. Navarro ◽  
Emma N. Zambrana-Infantes ◽  
...  

Alzheimer’s disease (AD) is the most common form of neurodegeneration and dementia. The endocannabinoid (ECB) system has been proposed as a novel therapeutic target to treat AD. The present study explores the expression of the ECB system, the ECB-related receptor GPR55, and cognitive functions (novel object recognition; NOR) in the 5xFAD (FAD: family Alzheimer’s disease) transgenic mouse model of AD. Experiments were performed on heterozygous (HTZ) and homozygous (HZ) 11 month old mice. Protein expression of ECB system components, neuroinflammation markers, and β-amyloid (Aβ) plaques were analyzed in the hippocampus. According to the NOR test, anxiety-like behavior and memory were altered in both HTZ and HZ 5xFAD mice. Furthermore, both animal groups displayed a reduction of cannabinoid (CB1) receptor expression in the hippocampus, which is related to memory dysfunction. This finding was associated with indirect markers of enhanced ECB production, resulting from the combination of impaired monoacylglycerol lipase (MAGL) degradation and increased diacylglycerol lipase (DAGL) levels, an effect observed in the HZ group. Regarding neuroinflammation, we observed increased levels of CB2 receptors in the HZ group that positively correlate with Aβ’s accumulation. Moreover, HZ 5xFAD mice also exhibited increased expression of the GPR55 receptor. These results highlight the importance of the ECB signaling for the AD pathogenesis development beyond Aβ deposition.


2020 ◽  
Vol 21 (12) ◽  
pp. 4532 ◽  
Author(s):  
Sujin Kim ◽  
Hyunju Chung ◽  
Han Ngoc Mai ◽  
Yunkwon Nam ◽  
Soo Jung Shin ◽  
...  

Alzheimer’s disease (AD) is the most common type of dementia. AD involves major pathologies such as amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain. During the progression of AD, microglia can be polarized from anti-inflammatory M2 to pro-inflammatory M1 phenotype. The activation of triggering receptor expressed on myeloid cells 2 (TREM2) may result in microglia phenotype switching from M1 to M2, which finally attenuated Aβ deposition and memory loss in AD. Low-dose ionizing radiation (LDIR) is known to ameliorate Aβ pathology and cognitive deficits in AD; however, the therapeutic mechanisms of LDIR against AD-related pathology have been little studied. First, we reconfirm that LDIR (two Gy per fraction for five times)-treated six-month 5XFAD mice exhibited (1) the reduction of Aβ deposition, as reflected by thioflavins S staining, and (2) the improvement of cognitive deficits, as revealed by Morris water maze test, compared to sham-exposed 5XFAD mice. To elucidate the mechanisms of LDIR-induced inhibition of Aβ accumulation and memory loss in AD, we examined whether LDIR regulates the microglial phenotype through the examination of levels of M1 and M2 cytokines in 5XFAD mice. In addition, we investigated the direct effects of LDIR on lipopolysaccharide (LPS)-induced production and secretion of M1/M2 cytokines in the BV-2 microglial cells. In the LPS- and LDIR-treated BV-2 cells, the M2 phenotypic marker CD206 was significantly increased, compared with LPS- and sham-treated BV-2 cells. Finally, the effect of LDIR on M2 polarization was confirmed by detection of increased expression of TREM2 in LPS-induced BV2 cells. These results suggest that LDIR directly induced phenotype switching from M1 to M2 in the brain with AD. Taken together, our results indicated that LDIR modulates LPS- and Aβ-induced neuroinflammation by promoting M2 polarization via TREM2 expression, and has beneficial effects in the AD-related pathology such as Aβ deposition and memory loss.


1979 ◽  
Vol 150 (2) ◽  
pp. 256-266 ◽  
Author(s):  
E L Morgan ◽  
W O Weigle

The proliferative response of mouse B lymphocytes induced by Fc fragments was found to be dependent upon an adherent cell population. The adherent cell is esterase positive, irradiation resistant, and not susceptible to lysis by anti-thymus serum and complement. The mechanism(s) by which Fc fragments induce B-cell proliferation could be the result of the interaction of Fc with both B cells and adherent cells or with adherent cells which then release factors that trigger the B cells to proliferate. Spleen cells from the C3H/HeJ mouse were shown to be unable to respond to Fc fragments. The addition of adherent cells from either C3H/St or C3H/HeN mice to adherent cell depleted C3H/HeJ cells enabled them to respond to Fc, indicating the defect was in the adherent cell population.


Author(s):  
Liu-Lin Xiong ◽  
Lu-Lu Xue ◽  
Ruo-Lan Du ◽  
Rui-Ze Niu ◽  
Li Chen ◽  
...  

AbstractIn recent years, biomarkers have been integrated into the diagnostic process and have become increasingly indispensable for obtaining knowledge of the neurodegenerative processes in Alzheimer’s disease (AD). Peripheral blood mononuclear cells (PBMCs) in human blood have been reported to participate in a variety of neurodegenerative activities. Here, a single-cell RNA sequencing analysis of PBMCs from 4 AD patients (2 in the early stage, 2 in the late stage) and 2 normal controls was performed to explore the differential cell subpopulations in PBMCs of AD patients. A significant decrease in B cells was detected in the blood of AD patients. Furthermore, we further examined PBMCs from 43 AD patients and 41 normal subjects by fluorescence activated cell sorting (FACS), and combined with correlation analysis, we found that the reduction in B cells was closely correlated with the patients’ Clinical Dementia Rating (CDR) scores. To confirm the role of B cells in AD progression, functional experiments were performed in early-stage AD mice in which fibrous plaques were beginning to appear; the results demonstrated that B cell depletion in the early stage of AD markedly accelerated and aggravated cognitive dysfunction and augmented the Aβ burden in AD mice. Importantly, the experiments revealed 18 genes that were specifically upregulated and 7 genes that were specifically downregulated in B cells as the disease progressed, and several of these genes exhibited close correlation with AD. These findings identified possible B cell-based AD severity, which are anticipated to be conducive to the clinical identification of AD progression.


2020 ◽  
Author(s):  
Jahirul Islam ◽  
Jung-Ah Cho ◽  
Ju-yong Kim ◽  
Kyung-Sun Park ◽  
Young-Jae koh ◽  
...  

Abstract Amyloid β (Aβ) and/or ATP activates NLRP3 inflammasome (N3I) by P2 × 7R ion channel of microglia, which is crucial in neuroinflammation shown in Alzheimer’s disease (AD). Due to polymorphisms, subtypes, and ubiquitous expression of P2 × 7R, inhibition of P2 × 7R has not been effective for AD. We first report that GPCR19 is a prerequisite for P2 × 7R-mediated N3I activation and Taurodeoxycholate (TDCA), a GPCR19 ligand, inhibited the priming phase of N3I activation, suppressed P2 × 7R expression and P2 × 7R-mediated Ca++ mobilization, and N3I oligomerization which is essential for production of IL-1β/IL-18. Further, TDCA increased expression of scavenger receptor (SR) A, enhanced phagocytosis of Aβ, and decreased Aβ plaque numbers in the brain of 5x Familial Alzheimer’s disease (5xFAD) mice. TDCA also reduced microgliosis, prevented neuronal loss, and improved memory function of 5xFAD mice. The pleiotropic roles of GPCR19 in P2 × 7-mediated N3I activation suggest that targeting GPCR19 might resolve neuroinflammation in AD patients.


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