| 1. |
- 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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| 2. |
- Carlsson, Ylva, 1975, et al.
(författare)
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Genetic inhibition of caspase-2 reduces hypoxic-ischemic and excitotoxic neonatal brain injury.
- 2011
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Ingår i: Annals of neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 70:5, s. 781-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Perinatal brain injury is a major cause of neurodevelopmental handicaps. Multiple pathways of oxidant stress, inflammation, and excitotoxicity lead to cell damage and death, including caspase-dependent apoptosis. Caspase-2 (Casp2; Nedd-2, Ich-1) is a developmentally regulated initiator caspase, which poorly cleaves other caspases but can initiate mitochondrial outer membrane permeabilization. We have investigated if Casp2 could mediate perinatal ischemic brain damage. METHODS: Casp2 expression in human neonatal brains and developmental patterns in rats and mice were evaluated. Casp2-deficient (Casp2(-/-) ), wild-type (WT), and heterozygous (Casp2(+/-) ) newborn C57BL/6 mice were subjected to hypoxia-ischemia (unilateral carotid occlusion + exposure to 10% oxygen for 50 minutes) or intracerebral injection of the excitotoxic N-methyl-D-aspartate-receptor agonist ibotenate. In addition, Casp2 specific siRNAs were preinjected into the brain of WT newborn mice 24 hours before ibotenate treatment. Brain tissues were examined by immunohistochemical staining (cresyl violet, MAP2, NF68, Casp2, Casp3) and Western blotting. Lesion volumes and injury in the cortical plates and white matter were quantified together with activated Casp3. RESULTS: Casp2 is highly expressed in the neonatal brain. Casp2-deficient mice subjected to hypoxia-ischemia at postnatal day 9 present significantly lower cerebral infarction, reduced white matter injury, and reduced Casp3 activation in the thalamus and hippocampus. Both Casp2(-/-) mice and siRNA-administered WT mice conferred reduction of gray and white matter injury after excitotoxic insult at postnatal day 5. Casp3 activation was also found reduced in Casp2-deficient mice subjected to excitotoxicity. INTERPRETATION: These data suggest for the first time a role of Casp2 in neonatal brain damage. ANN NEUROL 2011;
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| 3. |
- Chhor, Vibol, et al.
(författare)
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Role of microglia in a mouse model of paediatric traumatic brain injury.
- 2017
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 1090-2139 .- 0889-1591. ; 63, s. 197-209
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Tidskriftsartikel (refereegranskat)abstract
- The cognitive and behavioural deficits caused by traumatic brain injury (TBI) to the immature brain are more severe and persistent than TBI in the mature brain. Understanding this developmental sensitivity is critical as children under four years of age sustain TBI more frequently than any other age group. Microglia (MG), resident immune cells of the brain that mediate neuroinflammation, are activated following TBI in the immature brain. However, the type and temporal profile of this activation and the consequences of altering it are still largely unknown. In a mouse model of closed head weight drop paediatric brain trauma, we characterized i) the temporal course of total cortical neuroinflammation and the phenotype of ex vivo isolated CD11B-positive microglia/macrophage (MG/MΦ) using a battery of 32 markers, and ii) neuropathological outcome 1 and 5days post-injury. We also assessed the effects of targeting MG/MΦ activation directly, using minocycline a prototypical microglial activation antagonist, on these processes and outcome. TBI induced a moderate increase in both pro- and anti-inflammatory cytokines/chemokines in the ipsilateral hemisphere. Isolated cortical MG/MΦ expressed increased levels of markers of endogenous reparatory/regenerative and immunomodulatory phenotypes compared with shams. Blocking MG/MΦ activation with minocycline at the time of injury and 1 and 2days post-injury had only transient protective effects, reducing ventricular dilatation and cell death 1day post-injury but having no effect on injury severity at 5days. This study demonstrates that, unlike in adults, the role of MG/MΦ in injury mechanisms following TBI in the immature brain may not be negative. An improved understanding of MG/MΦ function in paediatric TBI could support translational efforts to design therapeutic interventions.
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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. |
- Sun, Xiaoyan, et al.
(författare)
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Association of neurogranin gene expression with Alzheimer's disease pathology in the perirhinal cortex.
- 2021
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Ingår i: Alzheimer's & dementia (New York, N. Y.). - : Wiley. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Synaptic damage is a key pathology of Alzheimer's disease (AD). The mechanism underlying synaptic vulnerability in AD remains elusive.Using a large-scale transcriptomic dataset, we analyzed the neurogranin-centered integrative gene network and assessed the correlation of neurogranin (NRGN) gene expression with AD pathology in post mortem brains. We studied the association of NRGN expression with Clinical Dementia Rating (CDR) and neuropathological diagnosis of AD.We find that the genes positively correlated with NRGN expression in AD are involved in synaptic transmission and cation channel pathways. NRGN expression is correlated with amyloid and tau pathology in the perirhinal cortex of post mortem brains. NRGN expression is associated with the diagnosis of AD and correlated with CDR.Transcriptional regulation of the gene encoding for synaptic protein is involved in selective synaptic damage in AD. Identifying the genes associated with synaptic damage pathways in AD may provide targets for intervention.
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| 6. |
- Thornton, Claire, et al.
(författare)
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Molecular mechanisms of neonatal brain injury.
- 2012
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Ingår i: Neurology research international. - : Hindawi Limited. - 2090-1860 .- 2090-1852. ; 2012
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Tidskriftsartikel (refereegranskat)abstract
- Fetal/neonatal brain injury is an important cause of neurological disability. Hypoxia-ischemia and excitotoxicity are considered important insults, and, in spite of their acute nature, brain injury develops over a protracted time period during the primary, secondary, and tertiary phases. The concept that most of the injury develops with a delay after the insult makes it possible to provide effective neuroprotective treatment after the insult. Indeed, hypothermia applied within 6 hours after birth in neonatal encephalopathy reduces neurological disability in clinical trials. In order to develop the next generation of treatment, we need to know more about the pathophysiological mechanism during the secondary and tertiary phases of injury. We review some of the critical molecular events related to mitochondrial dysfunction and apoptosis during the secondary phase and report some recent evidence that intervention may be feasible also days-weeks after the insult.
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| 7. |
- Vontell, Regina, et al.
(författare)
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Cellular mechanisms of toll-like receptor-3 activation in the thalamus are associated with white matter injury in the developing brain.
- 2015
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Ingår i: Journal of neuropathology and experimental neurology. - 1554-6578. ; 74:3, s. 273-85
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Tidskriftsartikel (refereegranskat)abstract
- Toll-like receptor-3 (TLR3) has been identified in a variety of intracellular structures (e.g. endosomes and endoplasmic reticulum); it detects viral molecular patterns and damage-associated molecular patterns. We hypothesized that, after white matter injury (WMI) has occurred, localization and activation of TLR3 are altered in gray matter structures in response to damage-associated molecular patterns and activated glia. Therefore, we investigated the subcellular localization of TLR3 and its downstream signaling pathway in postmortem brain sections from preterm infants with and without WMI (7 patients each). We assessed astroglia (glial fibrillary acidic protein-positive), microglia (ionized calcium-binding adaptor molecule-1-positive), and neuronal populations in 3 regions of the thalamus and in the posterior limb of the internal capsule and analyzed TLR3 messenger RNA and protein expression in the ventral lateral posterior thalamic region, an area associated with impaired motor function. We also assessed TLR3 colocalization with late endosomes (lysosome-associated membrane protein-1) and phagosomal compartments in this region. Glial fibrillary acidic protein, ionized calcium-binding adaptor molecule-1, and TLR3 immunoreactivity and messenger RNA expression were increased in cases with WMI compared with controls. In ventral lateral posterior neurons, TLR3 was colocalized with the endoplasmic reticulum and the autophagosome, suggesting that autophagy may be a stress response associated with WMI. Thus, alterations in TLR3 expression in WMI may be an underlying molecular mechanism associated with impaired development in preterm infants.
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| 8. |
- Vontell, Regina T., et al.
(författare)
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Association of region-specific hippocampal reduction of neurogranin with inflammasome proteins in post mortem brains of Alzheimer's disease
- 2024
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Ingår i: ALZHEIMERS & DEMENTIA-TRANSLATIONAL RESEARCH & CLINICAL INTERVENTIONS. - 2352-8737. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Neurogranin (Ng) is considered a biomarker for synaptic dysfunction in Alzheimer's disease (AD). In contrast, the inflammasome complex has been shown to exacerbate AD pathology.METHODS: We investigated the protein expression, morphological differences of Ng, and correlated Ng to hyperphosphorylated tau in the post mortem brains of 17 AD cases and 17 age- and sex-matched controls. In addition, we correlated the Ng expression with two different epitopes of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC).RESULTS: We show a reduction of Ng immunopositive neurons and morphological differences in AD compared to controls. Ng immunostaining was negatively correlated with neurofibrillary tangles, humanized anti-ASC (IC100) positive neurons and anti-ASC positive microglia, in AD.DISCUSSION: The finding of a negative correlation between Ng and ASC speck protein expression in post mortem brains of AD suggests that the activation of inflammasome/ASC speck pathway may play an important role in synaptic degeneration in AD.
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| 9. |
- 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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