scholarly journals Aging-associated deficit in CCR7 is linked to worsened glymphatic function, cognition, neuroinflammation, and β-amyloid pathology

2021 ◽  
Vol 7 (21) ◽  
pp. eabe4601
Author(s):  
Sandro Da Mesquita ◽  
Jasmin Herz ◽  
Morgan Wall ◽  
Taitea Dykstra ◽  
Kalil Alves de Lima ◽  
...  
Keyword(s):  
T Cells ◽  
Cognitive Decline ◽  
Brain Aging ◽  
Therapeutic Potential ◽  
T Cell Response ◽  
Age Related ◽  
Lymphatic Vasculature ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Old Mice

Aging leads to a progressive deterioration of meningeal lymphatics and peripheral immunity, which may accelerate cognitive decline. We hypothesized that an age-related reduction in C-C chemokine receptor type 7 (CCR7)–dependent egress of immune cells through the lymphatic vasculature mediates some aspects of brain aging and potentially exacerbates cognitive decline and Alzheimer’s disease–like brain β-amyloid (Aβ) pathology. We report a reduction in CCR7 expression by meningeal T cells in old mice that is linked to increased effector and regulatory T cells. Hematopoietic CCR7 deficiency mimicked the aging-associated changes in meningeal T cells and led to reduced glymphatic influx and cognitive impairment. Deletion of CCR7 in 5xFAD transgenic mice resulted in deleterious neurovascular and microglial activation, along with increased Aβ deposition in the brain. Treating old mice with anti-CD25 antibodies alleviated the exacerbated meningeal regulatory T cell response and improved cognitive function, highlighting the therapeutic potential of modulating meningeal immunity to fine-tune brain function in aging and in neurodegenerative diseases.

scholarly journals Development of Stable Chimeric IL-15 for Trans-Presentation by the Antigen Presenting Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Manoj Patidar ◽  
Naveen Yadav ◽  
Sarat K. Dalai
Keyword(s):  
T Cells ◽  
T Cell ◽  
Half Life ◽  
Therapeutic Potential ◽  
Chimeric Protein ◽  
Antigen Presenting Cells ◽  
T Cell Response ◽  
Antigen Presenting

IL-15 is one of the important biologics considered for vaccine adjuvant and treatment of cancer. However, a short half-life and poor bioavailability limit its therapeutic potential. Herein, we have structured IL-15 into a chimeric protein to improve its half-life enabling greater bioavailability for longer periods. We have covalently linked IL-15 with IgG2 base to make the IL-15 a stable chimeric protein, which also increased its serum half-life by 40 fold. The dimeric structure of this kind of IgG based biologics has greater stability, resistance to proteolytic cleavage, and less frequent dosing schedule with minimum dosage for achieving the desired response compared to that of their monomeric forms. The structured chimeric IL-15 naturally forms a dimer, and retains its affinity for binding to its receptor, IL-15Rβ. Moreover, with the focused action of the structured chimeric IL-15, antigen-presenting cells (APC) would transpresent chimeric IL-15 along with antigen to the T cell, that will help the generation of quantitatively and qualitatively better antigen-specific memory T cells. In vitro and in vivo studies demonstrate the biological activity of chimeric IL-15 with respect to its ability to induce IL-15 signaling and modulating CD8+ T cell response in favor of memory generation. Thus, a longer half-life, dimeric nature, and anticipated focused transpresentation by APCs to the T cells will make chimeric IL-15 a super-agonist for memory CD8+ T cell responses.

Aging

2019 ◽  
pp. 105-112
Author(s):  
Risto Näätänen ◽  
Teija Kujala ◽  
Gregory Light
Keyword(s):  
Hearing Loss ◽  
Speech Perception ◽  
Cognitive Decline ◽  
Temporal Processing ◽  
Brain Aging ◽  
Brain Plasticity ◽  
Part Of Speech ◽  
Memory Traces ◽  
Age Related ◽  
The Brain

This chapter shows that MMN and its magnetoencephalographic (MEG) equivalent MMNm are sensitive indices of aging-related perceptual and cognitive decline. Importantly, the age-related neural changes are associated with a decrease of general brain plasticity, i.e. that of the ability of the brain to form and maintain sensory-memory traces, a necessary basis for veridical perception and appropriate cognitive brain function. MMN/MMNm to change in stimulus duration is particularly affected by aging, suggesting the increased vulnerability of temporal processing to brain aging and accounting, for instance, for a large part of speech-perception difficulties of the aged beyond the age-related peripheral hearing loss.

scholarly journals Noncanonical function of an autophagy protein prevents spontaneous Alzheimer’s disease

2020 ◽  
Vol 6 (33) ◽  
pp. eabb9036
Author(s):  
Bradlee L. Heckmann ◽  
Brett J. W. Teubner ◽  
Emilio Boada-Romero ◽  
Bart Tummers ◽  
Clifford Guy ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Disease ◽  
Memory Impairment ◽  
Memory Loss ◽  
Tau Hyperphosphorylation ◽  
Primary Microglia ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Old Mice

Noncanonical functions of autophagy proteins have been implicated in neurodegenerative conditions, including Alzheimer’s disease (AD). The WD domain of the autophagy protein Atg16L is dispensable for canonical autophagy but required for its noncanonical functions. Two-year-old mice lacking this domain presented with robust β-amyloid (Aβ) pathology, tau hyperphosphorylation, reactive microgliosis, pervasive neurodegeneration, and severe behavioral and memory deficiencies, consistent with human disease. Mechanistically, we found this WD domain was required for the recycling of Aβ receptors in primary microglia. Pharmacologic suppression of neuroinflammation reversed established memory impairment and markers of disease pathology in this novel AD model. Therefore, loss of the Atg16L WD domain drives spontaneous AD in mice, and inhibition of neuroinflammation is a potential therapeutic approach for treating neurodegeneration and memory loss. A decline in expression of ATG16L in the brains of human patients with AD suggests the possibility that a similar mechanism may contribute in human disease.

scholarly journals Imbalance of Endocannabinoid/Lysophosphatidylinositol Receptors Marks the Severity of Alzheimer’s Disease in a Preclinical Model: A Therapeutic Opportunity

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 ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Receptor Expression ◽  
Preclinical Model ◽  
Diacylglycerol Lipase ◽  
Therapeutic Opportunity ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
5Xfad Mice ◽  
Old Mice

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.

scholarly journals A238 ABSENCE OF AGE-RELATED MEMORY DECLINE IN GERM-FREE MICE

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 288-289
Author(s):  
N Kraimi ◽  
G De Palma ◽  
J Lu ◽  
D Bowdish ◽  
E Verdu ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Spatial Memory ◽  
Cognitive Decline ◽  
Memory Performance ◽  
Alternation Rate ◽  
Memory Decline ◽  
Germ Free ◽  
Age Related ◽  
Old Mice ◽  
Young Mice

Abstract Background Age-associated deterioration of cognitive function and memory capacity occur in a variety of mammals, from humans to rodents. For example, significant memory deficits have been reported in conventionally raised (SPF) old mice compared to conventionally raised young mice submitted to a spatial memory task (Prevot et al., Mol Neuropsychiatry 2019). Microbiota to brain signaling is now well established in mice, but the extent to which this influences age-related memory decline is unknown. Aims Our project aims to determine whether the intestinal microbiota contributes to age-related changes in brain function. We address the hypothesis that age-related cognitive decline is attenuated in the absence of the intestinal microbiota. Methods We studied locomotor behavior and spatial memory performance in young germ-free (GF) mice (2–3 months of age, n=24) and senescent GF mice (13–27 months old, n=22) maintained in axenic conditions, and compared them to conventionally raised (SPF) mice. We used the Y-maze test based on a spontaneous alternations task to assess cognition, with alternation rate as a proxy of spatial working memory performance. The locomotor activity was measured using the open-field test. Results GF old mice traveled less distance (458.9 cm) than GF young mice (875.7 cm, p < 0.001) but these differences in locomotor activity did not influence spatial memory performance. Indeed, both GF old and GF young mice had an identical alternation rate of 73.3% (p > 0.05). This contrasted with the memory impairment found in old SPF mice that displayed lower alternation rate of 58.3%, compared to that found in young SPF mice (76.2%, p = 0.13). Conclusions We conclude that the absence of age-related memory decline in germ-free mice is consistent with a role for the microbiota in the cognitive decline associated with aging, likely through action on the immune system, well documented in SPF mice (Thevaranjan et al., Cell Host & Microbe 2017). We propose that novel microbiota-targeted therapeutic strategies may delay or prevent the cognitive decline of aging. Funding Agencies CIHRBalsam Family Foundation

scholarly journals Mild cognitive impairment (MCI) twenty years on

2011 ◽  
Vol 24 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Karen Ritchie ◽  
Craig W Ritchie
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Decline ◽  
Brain Aging ◽  
Cognitive Change ◽  
Cognitive Disorder ◽  
Everyday Functioning ◽  
Normal Limits ◽  
Age Related ◽  
The Usa

Cognitive decline has commonly been considered an inevitable result of brain aging and has been of clinical interest principally because of related difficulties with everyday functioning. Since the 1990s the “normality” of age-related cognitive decline has been called into question, being commonly attributed to a number of underlying disorders. Numerous concepts have been proposed which link subclinical cognitive change to pathological states (mild cognitive disorder, mild neurocognitive disorder, mild cognitive impairment). Of these, mild cognitive impairment (MCI) has become the most popular, driven on the one hand by industrial interests seeking to extend new dementia treatments for a more prevalent subclinical syndrome, and on the other by researchers attempting to identify at-risk populations. MCI has been both criticized for “medicalizing” behavior still within normal limits (Stephan et al., 2008; Moreira et al., 2008) and welcomed in that it suggests cognitive decline with aging may not be inevitable, but rather due to abnormalities which could ultimately be treated. Recently, in both Europe (DuBois et al., 2007) and the USA (Albert et al., 2011), panels of experts have scrutinized the concept of MCI and more broadly the pre-dementia stages of neurodegenerative diseases and offered new research diagnostic criteria. These proposed criteria have highlighted the (potential) value of biomarkers in assisting diagnosis, although some have considered the elevation of biomarkers to this level of importance in diagnosing disease before dementia develops to be premature given both the extent and quality of diagnostic biomarker data currently available (McShane et al., 2011a; 2011b).

scholarly journals Key role of T cell defects in age-related vulnerability to West Nile virus

2009 ◽  
Vol 206 (12) ◽  
pp. 2735-2745 ◽  
Author(s):  
James D. Brien ◽  
Jennifer L. Uhrlaub ◽  
Alec Hirsch ◽  
Clayton A. Wiley ◽  
Janko Nikolich-Žugich
Keyword(s):  
T Cells ◽  
West Nile Virus ◽  
T Cell ◽  
Cd8 T Cells ◽  
The Elderly ◽  
T Cell Response ◽  
West Nile ◽  
Immunodeficient Mice ◽  
Age Related ◽  
Cell Immunity

West Nile virus (WNV) infection causes a life-threatening meningoencephalitis that becomes increasingly more prevalent over the age of 50 and is 40–50× more prevalent in people over the age of 70, compared with adults under the age of 40. In a mouse model of age-related vulnerability to WNV, we demonstrate that death correlates with increased viral titers in the brain and that this loss of virus control with age was the result of defects in the CD4 and CD8 T cell response against WNV. Specific age-related defects in T cell responses against dominant WNV epitopes were detected at the level of cytokine and lytic granule production, each of which are essential for resistance against WNV, and in the ability to generate multifunctional anti-WNV effector T cells, which are believed to be critical for robust antiviral immunity. In contrast, at the peak of the response, old and adult T cells exhibited superimposable peptide sensitivity. Most importantly, although the adult CD4 or CD8 T cells readily protected immunodeficient mice upon adoptive transfer, old T cells of either subset were unable to provide WNV-specific protection. Consistent with a profound qualitative and quantitative defect in T cell immunity, old brains contained at least 12× fewer total effector CD8 T cells compared with adult mice at the peak of brain infection. These findings identify potential targets for immunomodulation and treatment to combat lethal WNV infection in the elderly.

scholarly journals RvE1 Impacts the Gingival Inflammatory Infiltrate by Inhibiting the T Cell Response in Experimental Periodontitis

2021 ◽  
Vol 12 ◽  
Author(s):  
Carla Alvarez ◽  
Henrique Abdalla ◽  
Salwa Sulliman ◽  
Paola Rojas ◽  
Yu-Chiao Wu ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Inflammatory Infiltrate ◽  
Alveolar Bone ◽  
Immune Cell ◽  
Therapeutic Potential ◽  
T Cell Response ◽  
Cervical Lymph Nodes ◽  
Wide Range ◽  
The Impact

Periodontitis is a chronic inflammatory disease associated with the formation of dysbiotic plaque biofilms and characterized by the progressive destruction of the alveolar bone. The transition from health to disease is characterized by a shift in periodontal immune cell composition, from mostly innate (neutrophils) to adaptive (T lymphocytes) immune responses. Resolvin E1 (RvE1) is a specialized pro-resolution mediator (SPMs), produced in response to inflammation, to enhance its resolution. Previous studies have indicated the therapeutic potential of RvE1 in periodontal disease; however, the impact of RvE1 in the microbial-elicited osteoclastogenic immune response remains uncharacterized in vivo. In the present study, we studied the impact of RvE1 on the gingival inflammatory infiltrate formation during periodontitis in a mouse model. First, we characterized the temporal-dependent changes of the main immune cells infiltrating the gingiva by flow cytometry. Then, we evaluated the impact of early or delayed RvE1 administration on the gingival immune infiltration and cervical lymph nodes composition. We observed a consistent inhibitory outcome on T cells -particularly effector T cells- and a protective effect on regulatory T cells (Tregs). Our data further demonstrated the wide range of actions of RvE1, its preventive role in the establishment of the adaptive immune response during inflammation, and bone protective capacity.

scholarly journals T-cell responses to acute cardiorespiratory or resistance exercise in cohorts of physically active or physically inactive older adults: A randomized complete crossover

2021 ◽  
Author(s):  
Rachel M. Graff ◽  
Kristofer Jennings ◽  
Emily C. LaVoy ◽  
Victoria E. Warren ◽  
Brad W. Macdonald ◽  
...  
Keyword(s):  
Older Adults ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Th17 Cells ◽  
T Cell Response ◽  
Moderate Intensity ◽  
Physically Active ◽  
Post Exercise ◽  
Age Related

AbstractAging is associated with many chronic diseases that are maintained and perpetuated by immune dysregulation and chronic systemic inflammation. T-cells often undergo age-related changes, including an accumulation of memory cells, which places individuals at increased risk for novel infections and may predispose them to increased inflammation. Regular exercise training has been suggested to offset age-related changes in T-cells, but the majority of literature is derived from cardiorespiratory exercise (CRE) studies. Much less is understood about the T-cell response to resistance exercise (RE). The purpose of this study was to examine the effects of acute CRE and acute RE on the T-cell response among a cohort of physically active older adults (PA) compared to a cohort of physically inactive older adults (PI).METHODSTwenty-four healthy older adults (PA n=12; PI n=12; mean ± SD; age (yrs) PA 62 ± 5, PI 64 ± 5; height (cm) PA 170.9 ± 6.9, PI 162.9 ± 8.0; weight (kg) PA 69.3 ± 10.2, PI 68.2 ± 12.8; BMI (kg/m2) PA 23.9 ± 3.0, PI 25.6 ± 3.5) completed one bout of CRE and one bout of RE in a randomized order, both at a moderate intensity, and separated by at least 7 days. Blood samples drawn pre-exercise, post-exercise, and 1h post-exercise (recovery) were analyzed for CD4+ and CD8+ T-cells and their differentiation status using surface markers CD45RA, CD62L, and CD57, as well as for Th17 cells (CD4+ CD161+ CD196+) using flow cytometry.RESULTSPI had higher numbers of circulating CD57+ EMRA CD4+ T-cells (PA, mean ± SE, 1 ± 2 cells/uL; PI, 6 ± 2 cells/uL; p=0.01; z=2.32) than PA at pre-exercise. Both CRE and RE elicited a significant mobilization of highly-differentiated (CD45RA+ CD62L-; CD57+ CD45RA+ CD62L-) CD8+ T-cells into the circulation post-exercise in both PA and PI groups. Furthermore, CRE resulted in a decrease in the number of circulating Th17 cells post-exercise, while RE increased Th17 cell mobilization compared to the CRE response.CONCLUSIONTaken together, T-cells in PA and PI respond similarly to acute CRE and support previously reported data showing a significant mobilization of highly differentiated T-cells. The present study confirms that moderate intensity RE also elicits this response, but highlights potential differences between CRE and RE on the immune responses of T-cells, particularly in PI individuals.Clinical trial registrationThis research study was registered at clinicaltrials.gov NCT03794050

scholarly journals Adaptive Immune Responses Mediated Age-related Plasmodium yoelii 17XL and 17XNL Infections in 4 and 8-week-old BALB/c Mice

2020 ◽  
Author(s):  
Qiu-bo Wang ◽  
Yun-ting Du ◽  
Fei Liu ◽  
Xiao-dan Sun ◽  
Xun Sun ◽  
...  
Keyword(s):  
T Cells ◽  
Survival Rate ◽  
Plasmodium Yoelii ◽  
Th2 Cells ◽  
Dependent Manner ◽  
Adaptive Immune ◽  
Age Related ◽  
Specific Igg ◽  
Ifn Γ ◽  
Old Mice

Abstract Backgroud: As the quest to eradicate malaria continues, it is important to clarify the opposite clinical outcomes between children and adulthood. The relationship between adaptive immune response and age-related malaria infection remains unknown.Methods: 4 and 8-week-old mice were used to mimic children and adulthood, respectively. Parasitemia and the survival rate were monitored. The proportion and function of Th1 and Th2 cells were detected by FACS. The levels of IFN-γ, IL-4, total IgG, IgG1, IgG2a and Plasmodium yoelii MSP-1-specific IgG were measured by ELISA.Results: Our results found that childhood mice were more susceptible to P. yoelii 17XNL infection, with lower survival rate and higher parasitemia. The adult group showed greater resistance to P. yoelii 17XL infection, with lower parasitemia. Compared with 4-week-old mice, the percentage of CD4+T-bet+IFN-γ+ Th1 cells as well as IFN-γ production were significantly increased on day 5 p.i. in the 8-week-old mice after P. yoelii 17XNL infection. The percentage of CD4+GATA3+IL-4+ Th2 cells and CD4+CXCR5+ Tfh cells, and IL-4 production in the 8-week-old mice significantly increased on day 5 and day 10 after P. yoelii 17XNL infection. Notably, the levels of total IgG, IgG1, IgG2a and P. yoelii MSP-1-specific IgG were also significantly increased in the 8-week-old mice. PD-1, a marker of exhaustion, was up-regulated on CD4+ or activated CD4+ T cells in the 8-week-old mice as compared to the 4-week-old group.Conclusions: Thus, we consider that enhanced cellular and humoral adaptive immunity might contribute to rapid clearance of malaria among adults, likely in a PD-1-dependent manner due to induction of CD4+ T cells exhaustion in P. yoelii 17XNL infected 8-week-old mice.

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