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Nikodemova M, Oberto JR, Berschel MR, Michaelson AL, Watters JJ, Mitchell GS. Acute Postnatal Inflammation Alters Adult Microglial Responses to LPS that Are Sex-, Region- and Timing of Postnatal Inflammation-Dependent. RESEARCH SQUARE 2024:rs.3.rs-4565866. [PMID: 38978595 PMCID: PMC11230508 DOI: 10.21203/rs.3.rs-4565866/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Background Adverse events in early life can have impact lasting into adulthood. We investigated the long-term effects of systemic inflammation during postnatal development on adult microglial responses to LPS in two CNS regions (cortex, cervical spinal cord) in male and female rats. Methods Inflammation was induced in Sprague-Dawley rats by lipopolysaccharide (LPS, 1 mg/kg) administered intraperitoneally during postnatal development at P7, P12 or P18. As adults (12 weeks of age), the rats received a second LPS dose (1 mg/kg). Control rats received saline. Microglia were isolated 3 hours post-LPS from the cortex and cervical spinal cord. Gene expression was assessed via qRT-PCR for pro-inflammatory (IL-6, iNOS, Ptgs2, C/EBPb, CD14, CXCL10), anti-inflammatory (CD68, Arg-1), and homeostatic genes (P2Y12, Tmemm119). CSF-1 and CX3CL1 mRNA was analyzed in microglia-free homogenates. Results Basal gene expression in adult microglia was largely unaffected by early life LPS. Changes in adult microglial pro-inflammatory genes in response to LPS were either unchanged or attenuated in rats exposed to LPS during postnatal development. Ptgs2, C/EBPb, CXCL10 and Arg-1 were the genes most affected, with expression levels significantly downregulated vs control rats without postnatal LPS exposure. Cortical microglia were affected more by postnatal inflammation than spinal microglia, and males were more impacted than females. Overall, inflammatory challenge at P18 had the greatest effect on adult microglial gene expression, whereas challenge at P7 had less impact. Microglial homeostatic genes were unaffected by postnatal LPS. Conclusions Long-lasting effects of postnatal inflammation on adult microglia depend on the timing of postnatal inflammation, CNS region and sex.
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Wardhani K, Yazzie S, McVeigh C, Edeh O, Grimes M, Jacquez Q, Dixson C, Barr E, Liu R, Bolt AM, Feng C, Zychowski KE. Systemic immunological responses are dependent on sex and ovarian hormone presence following acute inhaled woodsmoke exposure. Part Fibre Toxicol 2024; 21:27. [PMID: 38797836 PMCID: PMC11129474 DOI: 10.1186/s12989-024-00587-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/17/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Rural regions of the western United States have experienced a noticeable surge in both the frequency and severity of acute wildfire events, which brings significant challenges to both public safety and environmental conservation efforts, with impacts felt globally. Identifying factors contributing to immune dysfunction, including endocrinological phenotypes, is essential to understanding how hormones may influence toxicological susceptibility. METHODS This exploratory study utilized male and female C57BL/6 mice as in vivo models to investigate distinct responses to acute woodsmoke (WS) exposure with a focus on sex-based differences. In a second set of investigations, two groups were established within the female mouse cohort. In one group, mice experienced ovariectomy (OVX) to simulate an ovarian hormone-deficient state similar to surgical menopause, while the other group received Sham surgery as controls, to investigate the mechanistic role of ovarian hormone presence in driving immune dysregulation following acute WS exposure. Each experimental cohort followed a consecutive 2-day protocol with daily 4-h exposure intervals under two conditions: control HEPA-filtered air (FA) and acute WS to simulate an acute wildfire episode. RESULTS Metals analysis of WS particulate matter (PM) revealed significantly increased levels of 63Cu, 182W, 208Pb, and 238U, compared to filtered air (FA) controls, providing insights into the specific metal components most impacted by the changing dynamics of wildfire occurrences in the region. Male and female mice exhibited diverse patterns in lung mRNA cytokine expression following WS exposure, with males showing downregulation and females displaying upregulation, notably for IL-1β, TNF-α, CXCL-1, CCL-5, TGF-β, and IL-6. After acute WS exposure, there were notable differences in the responses of macrophages, neutrophils, and bronchoalveolar lavage (BAL) cytokines IL-10, IL-6, IL-1β, and TNF-α. Significant diverse alterations were observed in BAL cytokines, specifically IL-1β, IL-10, IL-6, and TNF-α, as well as in the populations of immune cells, such as macrophages and polymorphonuclear leukocytes, in both Sham and OVX mice, following acute WS exposure. These findings elucidated the profound influence of hormonal changes on inflammatory outcomes, delineating substantial sex-related differences in immune activation and revealing altered immune responses in OVX mice due to ovarian hormone deficiency. In addition, the flow cytometry analysis highlighted the complex interaction between OVX surgery, acute WS exposure, and their collective impact on immune cell populations within the hematopoietic bone marrow niche. CONCLUSIONS In summary, both male and female mice, alongside females subjected to OVX and those who had sham surgery, exhibit significant variations in the expression of proinflammatory cytokines, chemokines, lung mRNA gene expression, and related functional networks linked to signaling pathways. These differences potentially act as mediators of sex-specific and hormonal influences in the systemic inflammatory response to acute WS exposure during a wildfire event. Understanding the regulatory roles of genes expressed differentially under environmental stressors holds considerable implications, aiding in identifying sex-specific therapeutic targets for addressing acute lung inflammation and injury.
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Affiliation(s)
- Kartika Wardhani
- College of Nursing, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
- Biochemistry and Biotechnology Group (B-TEK), Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Sydnee Yazzie
- College of Nursing, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Charlotte McVeigh
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Onamma Edeh
- College of Nursing, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Martha Grimes
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Quiteria Jacquez
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Connor Dixson
- College of Nursing, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Edward Barr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Rui Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Alicia M Bolt
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Changjian Feng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA
| | - Katherine E Zychowski
- College of Nursing, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA.
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Balu D, Valencia-Olvera AC, Deshpande A, Narayanam S, Konasani S, Pattisapu S, York JM, Thatcher GRJ, LaDu MJ, Tai LM. Estradiol improves behavior in FAD transgenic mice that express APOE3 but not APOE4 after ovariectomy. Front Endocrinol (Lausanne) 2024; 15:1374825. [PMID: 38742194 PMCID: PMC11089251 DOI: 10.3389/fendo.2024.1374825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/02/2024] [Indexed: 05/16/2024] Open
Abstract
Increasing evidence suggests that female individuals have a higher Alzheimer's disease (AD) risk associated with post-menopausal loss of circulating estradiol (E2). However, clinical data are conflicting on whether E2 lowers AD risk. One potential contributing factor is APOE. The greatest genetic risk factor for AD is APOE4, a factor that is pronounced in female individuals post-menopause. Clinical data suggests that APOE impacts the response of AD patients to E2 replacement therapy. However, whether APOE4 prevents, is neutral, or promotes any positive effects of E2 is unclear. Therefore, our goal was to determine whether APOE modulates the impact of E2 on behavior and AD pathology in vivo. To that end, mice that express human APOE3 (E3FAD) or APOE4 (E4FAD) and overproduce Aβ42 were ovariectomized at either 4 months (early) or 8 months (late) and treated with vehicle or E2 for 4 months. In E3FAD mice, we found that E2 mitigated the detrimental effect of ovariectomy on memory, with no effect on Aβ in the early paradigm and only improved learning in the late paradigm. Although E2 lowered Aβ in E4FAD mice in the early paradigm, there was no impact on learning or memory, possibly due to higher Aβ pathology compared to E3FAD mice. In the late paradigm, there was no effect on learning/memory and Aβ pathology in E4FAD mice. Collectively, these data support the idea that, in the presence of Aβ pathology, APOE impacts the response to E2 supplementation post-menopause.
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Affiliation(s)
- Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Ana C. Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Ashwini Deshpande
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Saharsh Narayanam
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Sravya Konasani
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Shreya Pattisapu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Jason M. York
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | | | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Leon M. Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
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Baek DC, Kang JY, Lee JS, Lee EJ, Son CG. Linking alterations in estrogen receptor expression to memory deficits and depressive behavior in an ovariectomy mouse model. Sci Rep 2024; 14:6854. [PMID: 38514828 PMCID: PMC10958029 DOI: 10.1038/s41598-024-57611-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/20/2024] [Indexed: 03/23/2024] Open
Abstract
The high risk of neurological disorders in postmenopausal women is an emerging medical issue. Based on the hypothesis of altered estrogen receptors (ERα and β) after the decline of estrogen production, we investigated the changes in ERs expressions across brain regions and depressive/amnesic behaviors. C57BL/6J female mice were ovariectomized (OVX) to establish a menopausal condition. Along with behavior tests (anxiety, depression, and memory), the expression of ERs, microglial activity, and neuronal activity was measured in six brain regions (hippocampus, prefrontal cortex, striatum, raphe nucleus, amygdala, and hypothalamus) from 4 to 12 weeks after OVX. Mice exhibited anxiety- and depressive-like behaviors, as well as memory impairment. These behavioral alterations have been linked to a suppression in the expression of ERβ. The decreased ERβ expression coincided with microglial-derived neuroinflammation, as indicated by notable activations of Ionized calcium-binding adapter molecule 1 and Interleukin-1beta. Additionally, the activity of brain-derived neurotrophic factor (BDNF), particularly in the hippocampus, decreased in a time-dependent manner from 4 to 12 weeks post-OVX. Our study provides evidence shedding light on the susceptibility to memory impairment and depression in women after menopause. This susceptibility is associated with the suppression of ERβ and alteration of ERα in six brain regions.
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Affiliation(s)
- Dong-Cheol Baek
- Institute of Bioscience & Integrative Medicine, Daejeon Korean Hospital of Daejeon University, Daedukdae-ro 176 bun-gil 75, Daejeon, 35235, Republic of Korea
| | - Ji-Yun Kang
- Institute of Bioscience & Integrative Medicine, Daejeon Korean Hospital of Daejeon University, Daedukdae-ro 176 bun-gil 75, Daejeon, 35235, Republic of Korea
| | - Jin-Seok Lee
- Institute of Bioscience & Integrative Medicine, Daejeon Korean Hospital of Daejeon University, Daedukdae-ro 176 bun-gil 75, Daejeon, 35235, Republic of Korea
| | - Eun-Jung Lee
- Department of Korean Rehabilitation Medicine, Daejeon Korean Hospital of Daejeon University, Daedukdae-ro 176 bun-gil 75, Daejeon, 35235, Republic of Korea
| | - Chang-Gue Son
- Institute of Bioscience & Integrative Medicine, Daejeon Korean Hospital of Daejeon University, Daedukdae-ro 176 bun-gil 75, Daejeon, 35235, Republic of Korea.
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Vega-Rivera NM, Estrada-Camarena E, Azpilcueta-Morales G, Cervantes-Anaya N, Treviño S, Becerril-Villanueva E, López-Rubalcava C. Chronic Variable Stress and Cafeteria Diet Combination Exacerbate Microglia and c-fos Activation but Not Experimental Anxiety or Depression in a Menopause Model. Int J Mol Sci 2024; 25:1455. [PMID: 38338735 PMCID: PMC10855226 DOI: 10.3390/ijms25031455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/11/2024] [Accepted: 01/13/2024] [Indexed: 02/12/2024] Open
Abstract
The menopause transition is a vulnerable period for developing both psychiatric and metabolic disorders, and both can be enhanced by stressful events worsening their effects. The present study aimed to evaluate whether a cafeteria diet (CAF) combined with chronic variable stress (CVS) exacerbates anxious- or depressive-like behavior and neuronal activation, cell proliferation and survival, and microglia activation in middle-aged ovariectomized (OVX) rats. In addition, body weight, lipid profile, insulin resistance, and corticosterone as an index of metabolic changes or hypothalamus-pituitary-adrenal (HPA) axis activation, and the serum pro-inflammatory cytokines IL-6, IL-β, and TNFα were measured. A CAF diet increased body weight, lipid profile, and insulin resistance. CVS increased corticosterone and reduced HDL. A CAF produced anxiety-like behaviors, whereas CVS induced depressive-like behaviors. CVS increased serum TNFα independently of diet. A CAF and CVS separately enhanced the percentage of Iba-positive cells in the hippocampus; the combination of factors further increased Iba-positive cells in the ventral hippocampus. A CAF and CVS increased the c-fos-positive cells in the hippocampus; the combination of factors increased the number of positive cells expressing c-fos in the ventral hippocampus even more. The combination of a CAF and CVS generates a slight neuroinflammation process and neuronal activation in a hippocampal region-specific manner and differentially affects the behavior.
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Affiliation(s)
- Nelly Maritza Vega-Rivera
- Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente”, Mexico City 14370, Mexico; (N.M.V.-R.); (G.A.-M.); (N.C.-A.)
| | - Erika Estrada-Camarena
- Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente”, Mexico City 14370, Mexico; (N.M.V.-R.); (G.A.-M.); (N.C.-A.)
| | - Gabriel Azpilcueta-Morales
- Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente”, Mexico City 14370, Mexico; (N.M.V.-R.); (G.A.-M.); (N.C.-A.)
| | - Nancy Cervantes-Anaya
- Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente”, Mexico City 14370, Mexico; (N.M.V.-R.); (G.A.-M.); (N.C.-A.)
| | - Samuel Treviño
- Facultad de Química, Benemérita Universidad de Puebla, Puebla 72570, Mexico;
| | - Enrique Becerril-Villanueva
- Laboratorio de Psicoinmunología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente”, Mexico City 14370, Mexico;
| | - Carolina López-Rubalcava
- Departamento de Farmacobiología, Centro de Investigación y Estudios Avanzados del IPN, Mexico City 14330, Mexico;
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Reed EG, Keller-Norrell PR. Minding the Gap: Exploring Neuroinflammatory and Microglial Sex Differences in Alzheimer's Disease. Int J Mol Sci 2023; 24:17377. [PMID: 38139206 PMCID: PMC10743742 DOI: 10.3390/ijms242417377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/04/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Research into Alzheimer's Disease (AD) describes a link between AD and the resident immune cells of the brain, the microglia. Further, this suspected link is thought to have underlying sex effects, although the mechanisms of these effects are only just beginning to be understood. Many of these insights are the result of policies put in place by funding agencies such as the National Institutes of Health (NIH) to consider sex as a biological variable (SABV) and the move towards precision medicine due to continued lackluster therapeutic options. The purpose of this review is to provide an updated assessment of the current research that summarizes sex differences and the research pertaining to microglia and their varied responses in AD.
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Affiliation(s)
- Erin G. Reed
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44242, USA
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Ince LM, Darling JS, Sanchez K, Bell KS, Melbourne JK, Davis LK, Nixon K, Gaudet AD, Fonken LK. Sex differences in microglia function in aged rats underlie vulnerability to cognitive decline. Brain Behav Immun 2023; 114:438-452. [PMID: 37709153 PMCID: PMC10790303 DOI: 10.1016/j.bbi.2023.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/07/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023] Open
Abstract
Aging is associated with a significant shift in immune system reactivity ("inflammaging"), as basal inflammation increases but protective responses to infection are compromised. The immune system exhibits considerable sex differences, which may influence the process of inflammaging, including immune cell activation and behavioral consequences of immune signaling (i.e., impaired memory). Here, we test the hypothesis that sex differences in immune aging may mediate sex differences in cognitive decline. Aged male and female rats received peripheral immune stimulation using lipopolysaccharide (LPS), then molecular, cellular, and behavioral outcomes were assessed. We observed that LPS-treated aged male rats showed cognitive impairment and increased neuroinflammatory responses relative to adult males. In contrast, aged female rats did not display these aging-related deficits. Using transcriptomic and flow cytometry analyses, we further observed significant age- and sex- dependent changes in immune cell populations in the brain parenchyma and meninges, indicating a broad shift in the neuroinflammatory environment that may potentiate these behavioral effects. Ovariectomized aged female rats were also resistant to inflammation-induced memory deficits, indicating that ovarian hormones are not required for the attenuated neuroinflammation in aged females. Overall, our results indicate that males have amplified inflammatory priming with age, which contributes to age-associated cognitive decline. Our findings highlight sexual dimorphism in mechanisms of aging, and suggest that sex is a crucial consideration for identifying therapies for aging and neuroinflammation.
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Affiliation(s)
- Louise M Ince
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey S Darling
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Kevin Sanchez
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Kiersten S Bell
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Jennifer K Melbourne
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Lourdes K Davis
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA
| | - Kimberly Nixon
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| | - Andrew D Gaudet
- Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA; Department of Psychology, University of Texas at Austin, Austin, TX 78712, USA; Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA
| | - Laura K Fonken
- Division of Pharmacology & Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA.
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Balu D, Valencia-Olvera AC, Islam Z, Mielczarek C, Hansen A, Perez Ramos TM, York J, LaDu MJ, Tai LM. APOE genotype and sex modulate Alzheimer's disease pathology in aged EFAD transgenic mice. Front Aging Neurosci 2023; 15:1279343. [PMID: 38020764 PMCID: PMC10644540 DOI: 10.3389/fnagi.2023.1279343] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
Increasing evidence supports that age, APOE and sex interact to modulate Alzheimer's disease (AD) risk, however the underlying pathways are unclear. One way that AD risk factors may modulate cognition is by impacting amyloid beta (Aβ) accumulation as plaques, and/or neuroinflammation Therefore, the goal of the present study was to evaluate the extent to which age, APOE and sex modulate Aβ pathology, neuroinflammation and behavior in vivo. To achieve this goal, we utilized the EFAD mice, which express human APOE3 or APOE4 and have five familial AD mutations (FAD) that result in Aβ42 overproduction. We assessed Aβ levels, reactive glia and Morris water maze performance in 6-, 10-, 14-, and 18-month-old EFAD mice. Female APOE4 mice had the highest Aβ deposition, fibrillar amyloid deposits and neuroinflammation as well as earlier behavior deficits. Interestingly, we found that female APOE3 mice and male APOE4 mice had similar levels of pathology. Collectively our data support that the combination of APOE4 and female sex is the most detrimental combination for AD, and that at older ages, female sex may be equivalent to APOE4 genotype.
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Affiliation(s)
- Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Ana C. Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Zarak Islam
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
- University of Illinois College of Medicine, Chicago, IL, United States
| | - Clare Mielczarek
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Allison Hansen
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
- University of Illinois College of Medicine, Peoria, IL, United States
| | - Tamara M. Perez Ramos
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
- School of Medicine, St. George’s University, St. George’s, Grenada
| | - Jason York
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Leon M. Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
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Balu D, Valencia-Olvera AC, Nguyen A, Patnam M, York J, Peri F, Neumann F, LaDu MJ, Tai LM. A small-molecule TLR4 antagonist reduced neuroinflammation in female E4FAD mice. Alzheimers Res Ther 2023; 15:181. [PMID: 37858252 PMCID: PMC10585767 DOI: 10.1186/s13195-023-01330-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND APOE genotype is the greatest genetic risk factor for sporadic Alzheimer's disease (AD). APOE4 increases AD risk up to 12-fold compared to APOE3, an effect that is greater in females. Evidence suggests that one-way APOE could modulate AD risk and progression through neuroinflammation. Indeed, APOE4 is associated with higher glial activation and cytokine levels in AD patients and mice. Therefore, identifying pathways that contribute to APOE4-associated neuroinflammation is an important approach for understanding and treating AD. Human and in vivo evidence suggests that TLR4, one of the key receptors involved in the innate immune system, could be involved in APOE-modulated neuroinflammation. Consistent with that idea, we previously demonstrated that the TLR4 antagonist IAXO-101 can reduce LPS- and Aβ-induced cytokine secretion in APOE4 glial cultures. Therefore, the goal of this study was to advance these findings and determine whether IAXO-101 can modulate neuroinflammation, Aβ pathology, and behavior in mice that express APOE4. METHODS We used mice that express five familial AD mutations and human APOE3 (E3FAD) or APOE4 (E4FAD). Female and male E4FAD mice and female E3FAD mice were treated with vehicle or IAXO-101 in two treatment paradigms: prevention from 4 to 6 months of age or reversal from 6 to 7 months of age. Learning and memory were assessed by modified Morris water maze. Aβ deposition, fibrillar amyloid deposition, astrogliosis, and microgliosis were assessed by immunohistochemistry. Soluble levels of Aβ and apoE, insoluble levels of apoE and Aβ, and IL-1β were measured by ELISA. RESULTS IAXO-101 treatment resulted in lower Iba-1 coverage, lower number of reactive microglia, and improved memory in female E4FAD mice in both prevention and reversal paradigms. IAXO-101-treated male E4FAD mice also had lower Iba-1 coverage and reactivity in the RVS paradigm, but there was no effect on behavior. There was also no effect of IAXO-101 treatment on neuroinflammation and behavior in female E3FAD mice. CONCLUSION Our data supports that TLR4 is a potential mechanistic therapeutic target for modulating neuroinflammation and cognition in APOE4 females.
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Affiliation(s)
- Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Ana C Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Austin Nguyen
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Mehul Patnam
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Jason York
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Francesco Peri
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | | | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Leon M Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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