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- Ben-David, Yael, et al.
(författare)
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RIC3, the cholinergic anti-inflammatory pathway, and neuroinflammation
- 2020
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Ingår i: International Immunopharmacology. - : ELSEVIER. - 1567-5769 .- 1878-1705. ; 83
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Tidskriftsartikel (refereegranskat)abstract
- Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels having many functions including inflammation control, as part of the cholinergic anti-inflammatory pathway. Genome wide association studies implicated RIC3, a chaperone of nAChRs, in multiple sclerosis (MS), a neuroinflammatory disease. To understand the involvement of RIC3 in inflammatory diseases we examined its expression, regulation, and function in activated immune cells. Our results show that immune activation leads to dynamic changes in RIC3 expression, in a mouse model of MS and in human lymphocytes and macrophages. We also show similarities in the expression dynamics of RIC3 and CHRNA7, encoding for the alpha 7 nAChR subunit. Homomeric alpha 7 nAChRs were shown to mediate the anti-inflammatory effects of cholinergic agonists. Thus, similarity in expression dynamics between RIC3 and CHRNA7 is suggestive of functional concordance. Indeed, siRNA mediated silencing of RIC3 in a mouse macrophage cell line eliminates the anti-inflammatory effects of cholinergic agonists. Furthermore, we show increased average expression of RIC3 and CHRNA7 in lymphocytes from MS patients, and a strong correlation between expression levels of these two genes in MS patients but not in healthy donors. Together, our results are consistent with a role for RIC3 and for the mechanisms regulating its expression in inflammatory processes and in neuroinflammatory diseases.
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| 2. |
- Rostami, Jinar, et al.
(författare)
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Astrocytes have the capacity to act as antigen-presenting cells in the Parkinson's disease brain
- 2020
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMany lines of evidence suggest that accumulation of aggregated alpha-synuclein (αSYN) in the Parkinson’s disease (PD) brain causes infiltration of T cells. However, in which ways the stationary brain cells interact with the T cells remain elusive. Here, we identify astrocytes as potential antigen-presenting cells capable of activating T cells in the PD brain. Astrocytes are a major component of the nervous system, and accumulating data indicate that astrocytes can play a central role during PD progression.MethodsTo investigate the role of astrocytes in antigen presentation and T-cell activation in the PD brain, we analyzed post mortem brain tissue from PD patients and controls. Moreover, we studied the capacity of cultured human astrocytes and adult human microglia to act as professional antigen-presenting cells following exposure to preformed αSYN fibrils.ResultsOur analysis of post mortem brain tissue demonstrated that PD patients express high levels of MHC-II, which correlated with the load of pathological, phosphorylated αSYN. Interestingly, a very high proportion of the MHC-II co-localized with astrocytic markers. Importantly, we found both perivascular and infiltrated CD4+ T cells to be surrounded by MHC-II expressing astrocytes, confirming an astrocyte T cell cross-talk in the PD brain. Moreover, we showed that αSYN accumulation in cultured human astrocytes triggered surface expression of co-stimulatory molecules critical for T-cell activation, while cultured human microglia displayed very poor antigen presentation capacity. Notably, intercellular transfer of αSYN/MHC-II deposits occurred between astrocytes via tunneling nanotubes, indicating spreading of inflammation in addition to toxic protein aggregates.ConclusionsIn conclusion, our data from histology and cell culture studies suggest an important role for astrocytes in antigen presentation and T-cell activation in the PD brain, highlighting astrocytes as a promising therapeutic target in the context of chronic inflammation.
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| 3. |
- Rostami, Jinar, et al.
(författare)
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Prolyl oligopeptidase inhibition by KYP-2407 increases alpha-synuclein fibril degradation in neuron-like cells
- 2020
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Ingår i: Biomedicine and Pharmacotherapy. - : Elsevier BV. - 0753-3322 .- 1950-6007. ; 131
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Tidskriftsartikel (refereegranskat)abstract
- Growing evidence emphasizes insufficient clearance of pathological alpha-synuclein (αSYN) aggregates in the progression of Parkinson's disease (PD). Consequently, cellular degradation pathways represent a potential therapeutic target. Prolyl oligopeptidase (PREP) is highly expressed in the brain and has been suggested to increase αSYN aggregation and negatively regulate the autophagy pathway. Inhibition of PREP with a small molecule inhibitor, KYP-2407, stimulates autophagy and reduces the oligomeric species of αSYN aggregates in PD mouse models. However, whether PREP inhibition has any effects on intracellular αSYN fibrils has not been studied before. In this study, the effect of KYP2407 on αSYN preformed fibrils (PFFs) was tested in SH-SY5Y cells and human astrocytes. Immunostaining analysis revealed that both cell types accumulated αSYN PFFs intracellularly but KYP-2047 decreased intracellular αSYN deposits only in SH-SY5Y cells, as astrocytes did not show any PREP activity. Western blot analysis confirmed the reduction of high molecular weight αSYN species in SH-SY5Y cell lysates, and secretion of αSYN from SH-SY5Y cells also decreased in the presence of KYP-2407. Accumulation of αSYN inside the SH-SY5Y cells resulted in an increase of the auto-lysosomal proteins p62 and LC3BII, as well as calpain 1 and 2, which have been shown to be associated with PD pathology. Notably, treatment with KYP-2407 significantly reduced p62 and LC3BII levels, indicating an increased autophagic flux, and calpain 1 and 2 levels returned to normal in the presence of KYP-2407. Our findings indicate that PREP inhibition can potentially be used as therapy to reduce the insoluble intracellular αSYN aggregates.
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| 4. |
- Rostami, Jinar, 1992-
(författare)
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The role of glial cells in alpha-synuclein pathology : Focus on degradation, cell-to-cell propagation and inflammation
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Growing evidence emphasizes the role of astrocytes and microglia in Parkinson’s disease (PD) and Alzheimer’s disease (AD). Yet, little is known about their impact on specific disease processes and if their involvement is beneficial or detrimental. The aim of this thesis was to further investigate the role of astrocytes and microglia in PD and AD. To this purpose, cultured human astrocytes and microglia were exposed to aggregates of alpha-synuclein (αSYN) or amyloid-beta (Aβ), proteins that are central to PD and AD brain pathology, respectively.In Paper I, the toxicity and cell-to-cell spreading of aggregated αSYN in human astrocytes were evaluated. We found that astrocytes can engulf large amounts of αSYN aggregates, which are stored inside the cells instead of being degraded. This intracellular storage was found to result in severe cellular stress. As a response, stressed astrocytes were shown to transfer αSYN via tunneling nanotubes (TNT) to healthy astrocytes.T cells have been observed to enter the PD brain, but little is known about which stationary cell types they interact with. In Paper II, the ability of astrocytes and microglia to act as antigen presenting cells in the presence of aggregated αSYN was investigated. Both astrocytes and microglia were capable of expressing major histocompatibility class I (MHCI) and MHCII. However, only astrocytes had the capacity to express other molecules crucial for T-cell activation, such as CD80 and CD86. MHCII expressing astrocytes were also found in close vicinity to T cells in the PD brain.In paper III, the cross-talk between microglia and astrocytes in the presence of αSYN and Aβ aggregates was examined. When cultured separately, microglia appeared to degrade αSYN and Aβ better than astrocytes. However, co-culture experiments showed that microglia and astrocytes have a synergistic effect on the clearance of protein aggregates. Cell-to-cell contact was revealed as one of the possible mechanisms by which astrocytes and microglia communicate with each other.In Paper IV, the molecular mechanisms by which the compound KYP-2407 enhances αSYN clearance was investigated. We found that KYP-2407 stimulates the auto-lysosomal pathway in the presence of αSYN aggregates. Calpain proteins, which increase αSYN aggregation and diminish autophagy in PD, were also shown to be reduced in the presence of KYP-2407.Taken together, this thesis contributes with novel and important knowledge to the potential role of astrocytes and microglia in PD and AD.
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