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| 2. |
- Okroj, Marcin, et al.
(author)
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Characterization of the complement inhibitory function of Rhesus rhadinovirus complement control protein (RCP).
- 2009
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In: Journal of Biological Chemistry. - 1083-351X. ; 2008:Nov 6., s. 505-514
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Journal article (peer-reviewed)abstract
- Rhesus Rhadinovirus (RRV) is currently the closest known, fully sequenced homolog of human Kaposi's sarcoma-associated herpesvirus (KSHV). Both these viruses encode complement inhibitors: KSHV-complement control protein (KCP) and RRV-complement control protein (RCP). Previously we characterized in detail the functional properties of KCP as complement inhibitor. Herein, we performed comparative analyses for two variants of RCP protein, encoded by RRV strains H26-95 and 17577. Both RCP variants and KCP inhibited human and rhesus complement when tested in hemolytic assays measuring all steps of activation via the classical and the alternative pathway. RCP variants from both RRV strains supported C3b- and C4b-degradation by factor I and decay-acceleration of the classical C3 convertase, similar to KCP. Additionally, the 17577 RCP variant accelerated decay of the alternative C3 convertase, which was not seen for KCP. In contrast to KCP, RCP showed no affinity to heparin and is the first described complement inhibitor in which the binding site for C3b/C4b does not interact with heparin. Molecular modeling shows a structural disruption in the region of RCP that corresponds to the KCP-heparin binding site. This makes RRV a superior model for future in vivo investigations of complement evasion, as RCP does not play a supportive role in viral attachment as KCP does.
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| 3. |
- Okroj, Marcin, et al.
(author)
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Hypoxia increases susceptibility of non-small cell lung cancer cells to complement attack.
- 2009
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In: Cancer immunology, immunotherapy. - : Springer Science and Business Media LLC. - 1432-0851 .- 0340-7004. ; 58, s. 1773-1782
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Journal article (peer-reviewed)abstract
- The complement system can be specifically targeted to tumor cells due to molecular changes on their surfaces that are recognized by complement directly or via naturally occurring antibodies. However, tumor cells often overexpress membrane-bound complement inhibitors protecting them from complement attack. We have previously shown that non-small cell lung cancer (NSCLC) cells, additionally to membrane-bound inhibitors, produce substantial amounts of soluble regulators such as factor I (FI) and factor H (FH). Since low oxygen concentration is associated with rapidly growing solid tumors, we studied how NSCLC cells protect themselves from complement attack under hypoxic conditions. Unexpectedly, mRNA levels and secretion of both FI and FH were significantly decreased already after 24 h exposure to hypoxia while cell viability measured by XTT assay and annexin V/7-AAD staining was affected only marginally. Furthermore, we observed decrease of mRNA level and loss of membrane-bound complement inhibitor CD46 and increased deposition of early (C3b) and terminal (C9) complement components on hypoxic NSCLC cells. All three complement pathways (classical, lectin and alternative) were employed to deposit C3b on cell surface. Taken together, our results imply that under hypoxic conditions NSCLC give up some of their available defense mechanisms and become more prone to complement attack.
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| 4. |
- Andersson, Karin, 1972, et al.
(author)
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Inflammation in the hippocampus affects IGF1 receptor signaling and contributes to neurological sequelae in rheumatoid arthritis.
- 2018
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 115:51
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Journal article (peer-reviewed)abstract
- Rheumatoid arthritis (RA) is an inflammatory joint disease with a neurological component including depression, cognitive deficits, and pain, which substantially affect patients' quality of daily life. Insulin-like growth factor 1 receptor (IGF1R) signaling is one of the factors in RA pathogenesis as well as a known regulator of adult neurogenesis. The purpose of this study was to investigate the association between IGF1R signaling and the neurological symptoms in RA. In experimental RA, we demonstrated that arthritis induced enrichment of IBA1+ microglia in the hippocampus. This coincided with inhibitory phosphorylation of insulin receptor substrate 1 (IRS1) and up-regulation of IGF1R in the pyramidal cell layer of the cornus ammoni and in the dentate gyrus, reproducing the molecular features of the IGF1/insulin resistance. The aberrant IGF1R signaling was associated with reduced hippocampal neurogenesis, smaller hippocampus, and increased immobility of RA mice. Inhibition of IGF1R in experimental RA led to a reduction of IRS1 inhibition and partial improvement of neurogenesis. Evaluation of physical functioning and brain imaging in RA patients revealed that enhanced functional disability is linked with smaller hippocampus volume and aberrant IGF1R/IRS1 signaling. These results point to abnormal IGF1R signaling in the brain as a mediator of neurological sequelae in RA and provide support for the potentially reversible nature of hippocampal changes.
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| 5. |
- Aswendt, M., et al.
(author)
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Reactive astrocytes prevent maladaptive plasticity after ischemic stroke
- 2022
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In: Progress in Neurobiology. - : Elsevier BV. - 0301-0082. ; 209
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Journal article (peer-reviewed)abstract
- Restoration of functional connectivity is a major contributor to functional recovery after stroke. We investigated the role of reactive astrocytes in functional connectivity and recovery after photothrombotic stroke in mice with attenuated reactive gliosis (GFAP–/–Vim–/–). Infarct volume and longitudinal functional connectivity changes were determined by in vivo T2-weighted magnetic resonance imaging (MRI) and resting-state functional MRI. Sensorimotor function was assessed with behavioral tests, and glial and neural plasticity responses were quantified in the peri-infarct region. Four weeks after stroke, GFAP–/–Vim–/– mice showed impaired recovery of sensorimotor function and aberrant restoration of global neuronal connectivity. These mice also exhibited maladaptive plasticity responses, shown by higher number of lost and newly formed functional connections between primary and secondary targets of cortical stroke regions and increased peri-infarct expression of the axonal plasticity marker Gap43. We conclude that reactive astrocytes modulate recovery-promoting plasticity responses after ischemic stroke. © 2021
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| 6. |
- Bartoszek, Krzysztof, 1984-, et al.
(author)
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Performance of pseudo-likelihood estimator in modelling cells' proliferation with noisy measurements
- 2010
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In: Conference materials XII International Workshop for Young Mathematicians. ; , s. 21-42, s. 21-42
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Conference paper (other academic/artistic)abstract
- Branching processes are widely used to describe cell development and proliferation. Currently parameter estimation is studied in mathematical models describing the dynamics of cell cultures where we can get very accurate measurements of cell counts. In vivo samples we will not have this accuracy, here the noise levels can be very significant. We will study a newly proposed pseudo-likelihood estimator of a multitype Bellman-Harris process modelling cell development and see how it performs under noisy measurements of cell counts.
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| 7. |
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| 8. |
- Laterza, Cecilia, et al.
(author)
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Attenuation of reactive gliosis in stroke-injured mouse brain does not affect neurogenesis from grafted human iPSC-derived neural progenitors
- 2018
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:2
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Journal article (peer-reviewed)abstract
- Induced pluripotent stem cells (iPSCs) or their progeny, derived from human somatic cells, can give rise to functional improvements after intracerebral transplantation in animal models of stroke. Previous studies have indicated that reactive gliosis, which is associated with stroke, inhibits neurogenesis from both endogenous and grafted neural stem/progenitor cells (NSPCs) of rodent origin. Here we have assessed whether reactive astrocytes affect the fate of human iPSC-derived NSPCs transplanted into stroke-injured brain. Mice with genetically attenuated reactive gliosis (deficient for GFAP and vimentin) were subjected to cortical stroke and cells were implanted adjacent to the ischemic lesion one week later. At 8 weeks after transplantation, immunohistochemical analysis showed that attenuated reactive gliosis did not affect neurogenesis or commitment towards glial lineage of the grafted NSPCs. Our findings, obtained in a human-to-mouse xenograft experiment, provide evidence that the reactive gliosis in stroke-injured brain does not affect the formation of new neurons from intracortically grafted human iPSC-derived NSPCs. However, for a potential clinical translation of these cells in stroke, it will be important to clarify whether the lack of effect of reactive gliosis on neurogenesis is observed also in a human-to-human experimental setting.
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| 9. |
- Morán, Javier, 1986, et al.
(author)
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Intranasal C3a treatment ameliorates cognitive impairment in a mouse model of neonatal hypoxic-ischemic brain injury.
- 2017
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In: Experimental Neurology. - : Elsevier BV. - 0014-4886 .- 1090-2430. ; 290, s. 74-84
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Journal article (peer-reviewed)abstract
- Perinatal asphyxia-induced brain injury is often associated with irreversible neurological complications such as intellectual disability and cerebral palsy but available therapies are limited. Novel neuroprotective therapies as well as approaches stimulating neural plasticity mechanism that can compensate for cell death after hypoxia-ischemia (HI) are urgently needed. We previously reported that single i.c.v. injection of complement-derived peptide C3a 1h after HI induction prevented HI-induced cognitive impairment when mice were tested as adults. Here, we tested the effects of intranasal treatment with C3a on HI-induced cognitive deficit. Using the object recognition test, we found that intranasal C3a treated mice were protected from HI-induced impairment of memory function assessed 6weeks after HI induction. C3a treatment ameliorated HI-induced reactive gliosis in the hippocampus, while it did not affect the extent of hippocampal tissue loss, neuronal cell density, expression of the pan-synaptic marker synapsin I or the expression of growth associated protein 43. In conclusion, our results reveal that brief pharmacological treatment with C3a using a clinically feasible non-invasive mode of administration ameliorates HI-induced cognitive impairment. Intranasal administration is a plausible route to deliver C3a into the brain of asphyxiated infants at high risk of developing hypoxic-ischemic encephalopathy.
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| 10. |
- Na, Manli, et al.
(author)
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Deficiency of the complement component 3 but not factor B aggravates Staphylococcus aureus septic arthritis in mice.
- 2016
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In: Infection and immunity. - 1098-5522. ; 84:4, s. 930-939
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Journal article (peer-reviewed)abstract
- The complement system plays an essential role in the innate immune response and protection against bacterial infections. However, detailed knowledge regarding the role of complement in Staphylococcus aureus (S. aureus) septic arthritis is still largely missing. In this study, we elucidated the role of selected complement proteins in S. aureus septic arthritis. Mice lacking the complement component 3 (C3(-/-)), complement factor B (fB(-/-)), receptor for C3 derived anaphylatoxin C3a (C3aR(-/-)) and wild-type (WT) control mice were intravenously or intraarticularly inoculated with Staphylococcus aureus Newman strain. The clinical course of septic arthritis as well as histopathological and radiological changes in joints were assessed. After intravenous inoculation, arthritis severity and frequency was significantly higher in C3(-/-) mice compared to WT controls, whereas fB(-/-) mice displayed intermediate arthritis severity and frequency. This was in accordance with both histopathological and radiological findings. C3 but not fB deficiency was associated with larger weight loss, more frequent kidney abscesses, as well as higher bacterial burden in kidneys. S. aureus opsonised with C3(-/-) sera displayed decreased uptake by mouse peritoneal macrophages compared with bacteria opsonised with WT or fB(-/-) sera. C3aR deficiency had no effect on the course of hematogenous S. aureus septic arthritis. We conclude that C3 deficiency increases the susceptibility to hematogenous S. aureus septic arthritis and impairs host bacterial clearance, conceivably due to diminished opsonisation and phagocytosis of S. aureus.
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