No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / With urbanization, indoor exposure to microbial communities has changed significantly. While indoor bacterial exposure has decreased, indoor fungal exposure has increased. Along with increases in fungal species diversity, indoor air in urbanized countries is characterized by 1,000+ fold differences in mold spore density between buildings. Americans are estimated to spend ~87% of their lives in this new indoor environment, where airborne spore concentrations are unregulated. While the effects of mold exposure on certain respiratory diseases are well established, little is known about how inhaled mold affects extra-respiratory disease. Mold exposure is associated with central nervous system (CNS) symptoms in humans, but very little is known about how mold affects the CNS. Here, I show that subchronic inhalation of a common indoor mold, Aspergillus versicolor, causes neuroinflammatory gene transcription in five out of five brain regions tested, at both 1 and 2 days post inhalation. How peripheral inflammation from mold inhalation causes neuroinflammation is unknown. The mechanisms by which mold is inhaled and cleared implicate the lung, systemic circulation, and gastrointestinal tract as potential areas of immune response. After mold spores are inhaled and deposited in the lung, they are killed by antifungal immunity, cleared from the lung by the mucociliary escalator, swallowed, and excreted through the gastrointestinal tract. Molds produce many mycotoxins which enter enterohepatic recirculation with known toxic effects, including intestinal epithelial disruption. Mycotoxin concentrations in food are regulated in countries comprising ~85% of the world’s population. Inhaled molds produce these same mycotoxins, yet pulmonary exposure is unregulated. The multi-system effects of fungal exposure are poorly understood, and are part of a growing nascent field. Here, I discuss the current state of the indoor fungal environment, known health effects of mold exposure, how fungi activate the immune system, the CNS effects of a common indoor mold, how neuroinflammation from mold exposure might be occurring, future work needed for the systematic analysis of the CNS effects of mold, what is needed to determine the extent to which fungal exposure influences disease, and what might be done to mitigate those effects. / 2022-08-17

Indiana University-Purdue University Indianapolis (IUPUI) / Cerebral amyloid angiopathy (CAA) is characterized by the cerebrovascular deposition of amyloid. The mechanisms underlying the contribution of CAA to neurodegeneration are not fully understood. In this dissertation, there are three main chapters. The first chapter investigates existing evidence regarding the amyloid diversity in CAA and its relation to tau pathology and immune response, as well as the possible contribution of molecular and cellular mechanisms, previously associated with parenchymal amyloid in Alzheimer disease (AD) and AD-related dementias, to the pathogenesis of CAA. The second chapter demonstrates differential glial reactivity and activation associated with early-stage CAA in a mouse model of Familial Danish Dementia (FDD), a neurodegenerative disease characterized by vascular accumulation of Danish amyloid (ADan). We show that early-stage CAA is associated with dysregulation in immune response networks and lipid processing, severe astrogliosis with a neurotoxic A1-astrocytic phenotype, characterized by increased expression of Complement Component 3 (C3), and decreased levels of Triggering Receptor Expressed On Myeloid Cells 2 (Trem2) with no significant reactive microgliosis. Our results also indicate how cholesterol accumulation and Apolipoprotein E (ApoE) are associated with vascular amyloid deposits at the early stages of pathology. Furthermore, we demonstrate A1 astrocytic mediation of Trem2 and microglia homeostasis. In the final chapter, we addressed whether inflammatory stimulus of other cell types are capable of inducing a subtype of neurotoxic astrocytes. Here we show a subtype of C3+ neurotoxic astrocyte are induced by activated endothelial cells that is distinct from astrocytes classically activated by microglia. We show that endothelial activated astrocytes have upregulated expression of A1-astrocytic genes and exhibit a distinctive extracellular matrix remodeling profile. Finally, we demonstrate that endothelial activated astrocytes are Decorin-positive and are associated to vascular amyloid deposits but not parenchymal amyloid plaques in mouse models and AD/CAA patients. These findings show the existence of potentially extensive and subtle functional diversity of C3+-reactive astrocytes.

No description available.

Alzheimer’s Disease (AD) is the most common form of dementia. It is a fatal neurodegenerative disease that leads to both cognitive decline and altered psychological states. There is currently no cure for AD. The pathology of AD includes the clustering of insoluble amyloid-β (Aβ) plaques, tau tangles, and increased neuroinflammation. These pathological manifestations initially occur in the hippocampus (HPC), then continue to the prefrontal cortex (PFC), and occur throughout the brain as the disease progresses. The heightened neuroinflammatory state in AD is an essential point of focus in AD research. In this study, the novel oral anti-inflammatory tumor necrosis factor-α (TNF-α) inhibitor compound PD2244 was tested to observe its effects on sensorimotor gating using prepulse inhibition (PPI), spatial memory using Barnes Maze, anxiety using an elevated-T maze, and apathy by observing nest building behavior in both female and male 3xTg mice. The 3xTg mice are the only triple-transgenic models of AD that have both Aβ plaques and tau tangles and is also an accelerated mouse model of AD pathology onset. A specialized diet containing variable doses of PD2244 was given to 3xTg mice beginning at 6 months of age. The doses given were 0, 1, 3, 10, and 30 mg/kg of PD2244. Testing was then performed at 9, 12, and 15 months, where 15 months equated to thorough AD pathology. Regarding behavioral improvement, it was observed that all doses of PD2244 were effective to alleviate deficits in PPI at 9, 12, and 15 months of age. On the Barnes Maze, at 9 months of age the 10 mg/kg dose of PD2244 was effective to alleviate deficits, whereas at 12 months of age, 3 and 30 mg/kg dose of PD2244 was effective, and finally, at 15 months of age the 3, 10 and 30 mg/kg doses of PD2244 demonstrated efficacy to alleviate deficits in spatial memory performance. On the elevated T-maze, there were no effects at 9 months of age, but the 3 mg/kg dose of PD2244 resulted in anxiolytic effects at 12 and 15 months of age. Nest building behavior is also being observed in 15-month-old mice to determine effects of PD2244 on apathy since it is a common neuropsychiatric prodrome of AD. Finally, analysis of neurobiological markers has revealed that PD2244 reduced increases in the proinflammatory cytokines TNF-α and interkeukin-1β (IL-1β) at 15 months of age in the HPC. In addition, there is currently a project analyzing immunohistological staining of microglial cells in the HPC and PFC in 15-month-old animals. This project is designed to discover a novel, effective, anti-inflammatory treatment for cognitive deficits and increases in anxiety associate with AD.

Microglia, the resident immune cells of the brain, play a critical role in brain homeostasis and neurological disease progression. In neurodegenerative diseases, microglia acquire a neurodegenerative phenotype (MGnD), the function of which is poorly understood. MicroRNA-155 (miR-155), a multifunctional microRNA enriched in cells of the immune system, and Apolipoprotein E (APOE), a lipoprotein which is significantly associated with Alzheimer’s disease (AD) risk, critically regulate MGnD. However, the role of these molecules in AD pathogenesis remains unclear. Here, we report that microglial deletion of miR-155 induces an early MGnD response activation state via interferon-ɣ (IFNɣ) signaling in mice. This phenotypic transition increases plaque-associated Apoe, enhances amyloid plaque compaction, reduces neuritic dystrophy and attenuates plaque-associated synaptic degradation, resulting in improved cognition. These findings provide a novel mechanism detailing the phenotypic switch from homeostatic microglia to MGnD, and highlight the beneficial role of IFNɣ responsive MGnD in restricting neurodegenerative pathology and preserving cognitive function in a mouse model of AD. In addition, we demonstrate that Apoe deficient microglia induce an MGnD signature comparable to controls, but enhance MGnD physiological phenotypes including enhanced cognitive behavioral performance and reduced plaque associated neuritic dystrophy. Furthermore, we highlight a potential mechanism by which Apolipoprotein C-1 may attenuate synaptic ß-amyloid accumulation in a mouse model of AD. These findings may serve as the basis novel immunomodulatory therapies targeting microglial miR-155 and APOE to treat AD.

no / Cryptolepine, an indoloquinoline alkaloid in Cryptolepis sanguinolenta, has anti-inflammatory property. In this study, we aimed to evaluate the effects of cryptolepine on lipopolysaccharide (LPS)- induced neuroinflammation in rat microglia and its potential mechanisms. Microglial activation was induced by stimulation with LPS, and the effects of cryptolepine pretreatment on microglial activation and production of proinflammatory mediators, PGE2/COX-2, microsomal prostaglandin E2 synthase and nitric oxide/iNOS were investigated. We further elucidated the role of Nuclear Factor-kappa B (NF-κB) and the mitogen-activated protein kinases in the antiinflammatory actions of cryptolepine in LPS-stimulated microglia. Our results showed that cryptolepine significantly inhibited LPS-induced production of tumour necrosis factor-alpha (TNFα), interleukin-6 (IL-6), interleukin-1beta (IL-1β), nitric oxide, and PGE2. Protein and mRNA levels of COX-2 and iNOS were also attenuated by cryptolepine. Further experiments on intracellular signalling mechanisms show that IκB-independent inhibition of NF-κB nuclear translocation contributes to the anti-neuroinflammatory actions of cryptolepine. Results also show that cryptolepine inhibited LPS-induced p38 and MAPKAPK2 phosphorylation in the microglia. Cell viability experiments revealed that cryptolepine (2.5 and 5 μM) did not produce cytotoxicity in microglia. Taken together, our results suggest that cryptolepine inhibits LPS-induced microglial inflammation by partial targeting of NF-κB signalling and attenuation of p38/MAPKAPK2.

Alcohol use disorder (AUD) costs the U.S. billions of dollars each year and is a leading cause of preventable death. AUD leads to many health complications, and those who suffer from AUD will often have stress and anxiety disorder comorbidities. To better understand this connection between AUD and stress and anxiety disorders, restraint stress (RS) and chronic-intermittent ethanol exposure (CIE) procedures were used on rats to analyze neuroinflammation via ELISA in the infralimbic and prelimbic cortices, and the bed nucleus of the stria terminalis (BNST). Levels of proinflammatory cytokines, TNF-α and IL-1β, were found to be elevated across different tests in both males and females. This study builds upon previous work in the BNST and offers new information for future studies of stress and alcohol in the region.

BACKGROUND: Subarachnoid Hemorrhage (SAH) accounts for 3-5% of total stroke patients annually. Despite its rare incidence, SAH carries a 50% mortality rate. Survivors are often left with varying degrees of disability, many will never return to their previous jobs and require long-term care. One of the leading causes for this high mortality and morbidity rate in SAH is Delay Cerebral Ischemia (DCI). Researchers are now beginning to investigate neuroinflammation as the underlying cause for DCI. Studies have shown the activation of the innate immune system in the central nervous system is initiated by excess hemoglobin in the subarachnoid space. This process is mediated by the Toll-Like Receptor 4 expressed on the tissue-resident macrophages. Activated macrophages release pro-inflammatory cytokines and cause neuronal apoptosis in the surrounding tissue. However, macrophages may also mediate neuroprotection in SAH. A macrophage surface receptor called CD163 is responsible for the recognition and endocytosis of excess hemoglobin. The thesis provides a closer assessment of the neuroprotective role of macrophages in SAH patients. METHODS: Cerebrospinal fluid (CSF) was obtained from twenty three patients diagnosed with SAH (on day 1 and day 7 post-admission) or unruptured aneurysms. Immune cells were separated from CSF and analyzed by flow cytometry. The following antibody panel was used in this study: PE-anti-CD163, PeCy7-anti-CD15, and APC-anti-CD14. Macrophage expression of CD14 and CD163 was quantified using FlowJo. SAH patients were graded by the Hunt and Hess scale for the clinical states upon admission; modified Fisher scale for the size of the hemorrhage; and modified Rankin scale for clinical outcome at the time of discharge. RESULTS: Significant increase in macrophage CD14 and CD163 expression is observed in day 1 SAH patients (p<0.05) as compared to the control group. Male SAH patients have equivocal macrophages CD163 expression on day 1 as compared to the control group (p>0.05), and significantly higher expression on day 7 as compared to day 1(p<0.05). Female SAH patients have significantly higher macrophages CD163 expression on day 1 as compared to control patients (p<0.05), but slightly decreased expression on day 7 as compared to day 1(p>0.05). Lower macrophages CD163 expression is observed in SAH patients with more severe hemorrhage (marked by higher modified Fisher score), but not in patients with more severe clinical states at admission (marked by higher Hunt and Hess score). Furthermore, SAH patients with low day 1 macrophage CD163 expression and low expression on day 7 may be correlated with better clinical outcome (marked by lower modified Rankin score). However, more patients are required before correlation can be established. CONCLUSION: The data further support our previous findings in mouse SAH model that macrophages in the central nervous system may mediate inflammation via the increased expression TLR4, measured by increased expression of its co-receptor CD14. Macrophages also may be neuroprotective, mediated by increased expression of CD163 in SAH patients. The macrophage CD163 expression may be the key in determining clinical outcome in SAH patients, but additional patients are required to establish statistical significance. / 2017-06-16T00:00:00Z

京都大学 / 新制・課程博士 / 博士(医学) / 甲第25002号 / 医博第5036号 / 新制||医||1070(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 渡邉 大, 教授 大鶴 繁 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM