| 1. |
- Albertsson, Anna-Maj, et al.
(författare)
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The immune response after hypoxia-ischemia in a mouse model of preterm brain injury.
- 2014
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Ingår i: Journal of neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundPreterm brain injury consists primarily of periventricular leukomalacia accompanied by elements of gray-matter injury, and these injuries are associated with cerebral palsy and cognitive impairments. Inflammation is believed to be an important contributing factor to these injuries. The aim of this study was to examine the immune response in a postnatal day (PND) 5 mouse model of preterm brain injury induced by hypoxia-ischemia (HI) that is characterized by focal white and gray-matter injury.MethodsC57Bl/6 mice at PND 5 were subjected to unilateral HI induced by left carotid artery ligation and subsequent exposure to 10% O2 for 50 minutes, 70 minutes, or 80 minutes. At seven days post-HI, the white/gray-matter injury was examined. The immune responses in the brain after HI were examined at different time points after HI using RT-PCR and immunohistochemical staining.ResultsHI for 70 minutes in PND 5 mice induced local white-matter injury with focal cortical injury and hippocampal atrophy, features that are similar to those seen in preterm brain injury in human infants. HI for 50 minutes resulted in a small percentage of animals being injured, and HI for 80 minutes produced extensive infarction in multiple brain areas. Various immune responses, including changes in transcription factors and cytokines that are associated with a T-helper (Th)1/Th17-type response, an increased number of CD4+ T-cells, and elevated levels of triggering receptor expressed on myeloid cells 2 (TREM-2) and its adaptor protein DNAX activation protein of 12 kDa (DAP12) were observed using the HI 70 minute preterm brain injury model.ConclusionsWe have established a reproducible model of HI in PND 5 mice that produces consistent local white/gray-matter brain damage that is relevant to preterm brain injury in human infants. This model provides a useful tool for studying preterm brain injury. Both innate and adaptive immune responses are observed after HI, and these show a strong pro-inflammatory Th1/Th17-type bias. Such findings provide a critical foundation for future studies on the mechanism of preterm brain injury and suggest that blocking the Th1/Th17-type immune response might provide neuroprotection after preterm brain injury.
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| 2. |
- Albertsson, Anna-Maj, et al.
(författare)
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γδ T cells contribute to injury in the developing brain.
- 2018
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Ingår i: The American journal of pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 188:3, s. 757-767
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Tidskriftsartikel (refereegranskat)abstract
- Brain injury in premature infants, especially periventricular leukomalacia, is an important cause of neurological disabilities. Inflammation contributes to the development of perinatal brain injury, but the essential mediators leading to brain injury in early life remain largely unknown. Neonates have reduced capacity for mounting conventional αβT-cell responses. However γδT-cells are already functionally competent during early development and are important in early life immunity. We investigated the potential contribution of γδT-cells to preterm brain injury by using postmortem brains from human preterm infants with periventricular leukomalacia and two animal models of preterm brain injury-the hypoxic-ischemic mouse model and a fetal sheep asphyxia model. Large numbers of γδT-cells were observed in the brains of mice, sheep, and postmortem preterm infants after injury, and depletion of γδT-cells provided protection in the mouse model. The common γδT-cell associated cytokines interferon-γ and interleukin (IL)-17A were not detectable in the brain. Although there were increased mRNA levels of Il17f and Il22 in the mouse brains after injury, neither IL-17F nor IL-22 cytokines contributed to preterm brain injury. These findings highlight unique features of injury in the developing brain where, unlike injury in the mature brain, γδT-cells function as important initiators of injury independently of common γδT-cell associated cytokines. This new finding will help to identify therapeutic targets for preventing or treating preterm infants with brain injury.
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| 3. |
- Leavenworth, Jianmei W, et al.
(författare)
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Mobilization of natural killer cells inhibits development of collagen-induced arthritis.
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 108:35, s. 14584-9
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Tidskriftsartikel (refereegranskat)abstract
- Although natural killer (NK) cells have been implicated in regulating immune responses, their ability to modulate disease development in autoimmune arthritis has not been analyzed. Here we investigate the contribution of NK cells to regulating collagen-induced arthritis, a well-characterized preclinical model of human rheumatoid arthritis. We find that the disease is induced by the combined action of two CD4(+) T helper (T(H)) subsets: follicular T(H) cells and T(H)17 cells. Both CD4(+) T(H) subsets are highly susceptible to lysis by NK cells after activation. Administration of antibody that activates NK cells through blockade of its inhibitory CD94/NKG2A receptor allows enhanced elimination of pathogenic follicular T(H) and T(H)17 cells and arrest of disease progression. These results suggest that antibody-dependent enhancement of NK activity may yield effective, previously undescribed therapeutic approaches to this autoimmune disorder.
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| 4. |
- Nazmi, Arshed, et al.
(författare)
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Lymphocytes Contribute to the Pathophysiology of Neonatal Brain Injury
- 2018
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 9, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Periventricular leukomalacia (PVL) is the most common form of preterm brain injury affecting the cerebral white matter. This type of injury involves a multiphase process and is induced by many factors, including hypoxia-ischemia (HI) and infection. Previous studies have suggested that lymphocytes play a significant role in the pathogenesis of brain injury, and the aim of this study was to determine the contribution of lymphocyte subsets to preterm brain injury.Immunohistochemistry on brain sections from neonatal mice was performed to evaluate the extent of brain injury in wild-type and T cell and B cell-deficient neonatal mice (Rag1-/- mice) using a mouse model of HI-induced preterm brain injury. Flow cytometry was performed to determine the presence of different types of immune cells in mouse brains following HI. In addition, immunostaining for CD3 T cells and CD20 B cells was performed on postmortem preterm human infant brains with PVL.Mature lymphocyte-deficient Rag1- / - mice showed protection from white matter loss compared to wild type mice as indicated by myelin basic protein immunostaining of mouse brains. CD3+ T cells and CD20+ B cells were observed in the postmortem preterm infant brains with PVL. Flow cytometry analysis of mouse brains after HI-induced injury showed increased frequency of CD3+ T, αβT and B cells at 7days after HI in the ipsilateral (injured) hemisphere compared to the contralateral (control, uninjured) hemisphere.Lymphocytes were found in the injured brain after injury in both mice and humans, and lack of mature lymphocytes protected neonatal mice from HI-induced brain white matter injury. This finding provides insight into the pathology of perinatal brain injury and suggests new avenues for the development of therapeutic strategies.
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| 5. |
- Shen, Erxia, et al.
(författare)
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Control of Germinal Center Localization and Lineage Stability of Follicular Regulatory T Cells by the Blimp1 Transcription Factor
- 2019
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 29:7
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 The Author(s) Follicular regulatory T (TFR) cells are a specialized suppressive subset that controls the germinal center (GC) response and maintains humoral self-tolerance. The mechanisms that maintain TFR lineage identity and suppressive activity remain largely unknown. Here, we show that expression of Blimp1 by FoxP3+ TFR cells is essential for TFR lineage stability, entry into the GC, and expression of regulatory activity. Deletion of Blimp1 in TFR cells reduced FoxP3 and CTLA-4 expression and increased pro-inflammatory cytokines and spontaneous production of autoantibodies, including elevated IgE. Maintenance of TFR stability reflected Blimp1-dependent repression of the IL-23R-STAT3 axis and activation of the CD25-STAT5 pathway, while silenced IL-23R-STAT3 or increased STAT5 activation rescued the Blimp1-deficient TFR phenotype. Blimp1-dependent control of CXCR5/CCR7 expression also regulated TFR homing into the GC. These findings uncover a Blimp1-dependent TFR checkpoint that enforces suppressive activity and acts as a gatekeeper of GC entry.
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| 6. |
- Zhang, Lingling, et al.
(författare)
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Integrative analysis of γδT cells and dietary factors reveals predictive values for autism spectrum disorder in children
- 2023
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Ingår i: Brain, behavior, and immunity. - 0889-1591 .- 1090-2139. ; 111, s. 76-89
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Tidskriftsartikel (refereegranskat)abstract
- Background: Autism spectrum disorder (ASD) includes a range of multifactorial neurodevelopmental disabilities characterized by a variable set of neuropsychiatric symptoms. Immunological abnormalities have been considered to play important roles in the pathogenesis of ASD, but it is still unknown which abnormalities are more prominent. Methods: A total of 105 children with ASD and 105 age and gender-matched typically developing (TD) children were recruited. An eating and mealtime behavior questionnaire, dietary habits, and the Bristol Stool Scale were investigated. The immune cell profiles in peripheral blood were analyzed by flow cytometry, and cytokines (IFN-γ, IL-8, IL-10, IL-17A, and TNF-α) in plasma were examined by Luminex assay. The obtained results were further validated using an external validation cohort including 82 children with ASD and 51 TD children. Results: Compared to TD children, children with ASD had significant eating and mealtime behavioral changes and gastrointestinal symptoms characterized by increased food fussiness and emotional eating, decreased fruit and vegetable consumption, and increased stool astriction. The proportion of γδT cells was significantly higher in children with ASD than TD children (β: 0.156; 95% CI: 0.888 ∼ 2.135, p < 0.001) even after adjusting for gender, eating and mealtime behaviors, and dietary habits. In addition, the increased γδT cells were evident in all age groups (age < 48 months: β: 0.288; 95% CI: 0.420 ∼ 4.899, p = 0.020; age ≥ 48 months: β: 0.458; 95% CI: 0.694 ∼ 9.352, p = 0.024), as well as in boys (β: 0.174; 95% CI: 0.834 ∼ 2.625, p < 0.001) but not in girls. These findings were also confirmed by an external validation cohort. Furthermore, IL-17, but not IFN-γ, secretion by the circulating γδT cells was increased in ASD children. Machine learning revealed that the area under the curve in nomogram plots for increased γδT cells combined with eating behavior/dietary factors was 0.905, which held true in both boys and girls and in all the age groups of ASD children. The decision curves showed that children can receive significantly higher diagnostic benefit within the threshold probability range from 0 to 1.0 in the nomogram model. Conclusions: Children with ASD present with divergent eating and mealtime behaviors and dietary habits as well as gastrointestinal symptoms. In peripheral blood, γδT cells but not αβT cells are associated with ASD. The increased γδT cells combined with eating and mealtime behavior/dietary factors have a high value for assisting in the diagnosis of ASD.
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| 7. |
- Zhang, Xiaoli, et al.
(författare)
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γδT cells but not αβT cells contribute to sepsis-induced white matter injury and motor abnormalities in mice
- 2017
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Infection and sepsis are associated with brain white matter injury in preterm infants and the subsequent development of cerebral palsy. Methods In the present study, we used a neonatal mouse sepsis-induced white matter injury model to determine the contribution of different T cell subsets (αβT cells and γδT cells) to white matter injury and consequent behavioral changes. C57BL/6J wild-type (WT), T cell receptor (TCR) δ-deficient (Tcrd −/−, lacking γδT cells), and TCRα-deficient (Tcra −/−, lacking αβT cells) mice were administered with lipopolysaccharide (LPS) at postnatal day (PND) 2. Brain myelination was examined at PNDs 12, 26, and 60. Motor function and anxiety-like behavior were evaluated at PND 26 or 30 using DigiGait analysis and an elevated plus maze. Results White matter development was normal in Tcrd −/− and Tcrα −/− compared to WT mice. LPS exposure induced reductions in white matter tissue volume in WT and Tcrα −/− mice, but not in the Tcrd −/− mice, compared with the saline-treated groups. Neither LPS administration nor the T cell deficiency affected anxiety behavior in these mice as determined with the elevated plus maze. DigiGait analysis revealed motor function deficiency after LPS-induced sepsis in both WT and Tcrα −/− mice, but no such effect was observed in Tcrd −/− mice. Conclusions Our results suggest that γδT cells but not αβT cells contribute to sepsis-induced white matter injury and subsequent motor function abnormalities in early life. Modulating the activity of γδT cells in the early stages of preterm white matter injury might represent a novel therapeutic strategy for the treatment of perinatal brain injury.
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