Journal of Neuroinflammation最新文献

Parkinson's disease is a common neurodegenerative disease related to both genetic and environmental insults. Epidemiological studies have linked Helicobacter pylori (H. pylori) infection to Parkinson's disease risk, but the underlying mechanisms of this association remain unclear. In this study, we investigated whether chronic infection with a pathogenic H. pylori strain could induce α-synuclein aggregation or neurodegeneration, and whether infection clearance mitigates these effects. We also assessed whether H. pylori infection exacerbates α-synuclein pathology and neuron loss when combined with seeding of α-synuclein pathology. We find that chronic H. pylori infection induces a sustained immune response in the gut and plasma that leads to mild brain inflammation and dopaminergic neuron loss, independent of α-synuclein pathology. These effects are attenuated by eradication of the infection. In mice with α-synuclein pathology induced by pre-formed fibrils, H. pylori does not further exacerbate the extent of pathology or neuronal death. Together, these results suggest that H. pylori infection can lead to neurodegeneration through inflammatory mechanisms independent of α-synuclein aggregation. Our findings offer mechanistic insights into how pathogens could influence the risk and progression of Parkinson's disease.

Cognitive impairment is a prevalent extrapulmonary manifestation of COPD. However, existing reviews have not yet systematically linked COPD-related dysregulation of brain functional networks with clinical indicators. This review bridges this gap by elucidating the pathway from pulmonary pathology to cognitive deficits via central network dysfunction, synthesizing evidence across four dimensions: clinical manifestations; physiological and pathological mechanisms; fMRI-based brain network disorders; and promising treatments. Chronic hypoxia-induced neuroinflammation, oxidative stress, and systemic inflammation propagated via the lung-brain axis were the main pathogenesis of COPD-CI. Cognitive deficits in COPD patients primarily manifest as executive function and visuospatial impairment, with some reality distinctive neural network features showing aberrant functional connectivity between the default mode network and visual network. Long-term oxygen therapy, anti-inflammatory regimens, and cognitive rehabilitation demonstrate benefits in improving cognition. Large sample, cross-sectional study is needed in the future studies, and multimodal neuroimaging should be used to delineate spatiotemporal network dynamics in COPD-CI.

Neuroinflammation is implicated in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS). Amongst potential innate immune mediators of disease, Type I interferon (IFN-I) could play an important role due to its ability to inhibit protein synthesis and affect neuronal synapses and metabolism. These effects could be cell intrinsic or non-cell autonomous mediated by glia or immune cells. We examined IFN-I in rNLS8 mice that have been engineered to express doxycycline suppressible human Transactive response DNA binding protein 43 kDa (hTDP-43) with a defective nuclear localization signal (hTDP-43ΔNLS) regulated by the neurofilament heavy chain (NEFH) promoter. Following induction of hTDP-43ΔNLS in rNLS8 mice, we observed upregulation of IFN-I stimulated genes (ISG) and, specifically, activation of the DNA sensor, cyclic GMP-AMP synthase (cGAS), as determined by mass spectrometry identification of the cyclic dinucleotide, cGAMP, in whole brain. To determine the cellular source of IFN-I, we performed single nucleus RNA sequencing of whole brain. We observed that ISG were most highly upregulated in astrocytes suggesting that astrocytes themselves were largely responsible for IFN-I production and / or response in rNLS8 mice. This observation was confirmed by immunohistochemical and immunofluorescence staining of IFN-I stimulated proteins in astrocytes in the cerebrum, especially in the hippocampus. These results point to a pivotal role of astrocytes in responding to cell damage at a relatively early phase of disease which prior studies have shown is partially reversible.

Chronic stress precipitates depression, yet how gut-immune-brain interactions translate stress into mood pathology remains unclear. We tested the hypothesis that stress-primed small intestinal γδ T cells drive hippocampal mitochondrial dysfunction and depression-like behavior via interleukin-17A (IL-1A). In mice exposed to chronic restraint stress (CRS), we combined behavioral assays (open-field, sucrose-preference, tail-suspension, forced-swim), 16S rRNA profiling, fecal microbiota transplantation, Kaede photoconversion, conditional CD8α deletion in γδ T cells, hippocampal IL-17A overexpression, rapamycin treatment, and administration of the antidepressant arketamine. CRS increased gut and brain permeability, induced gut-microbiota dysbiosis, and promoted migration of small intestinal CD8α⁺ γδ T17 cells to the meninges and brain; γδ T cells were the predominant IL-17A source in the brain. Kaede tracing confirmed an intestinal origin, and CRS-associated microbiota alone transferred γδ T cell trafficking and depression-like behavior to recipients. In the hippocampus, CRS elevated IL-17A and impaired PINK1/Parkin-mediated mitophagy (decreased PINK1, Parkin, Beclin-1, and LC3B-II/I; increased p62), reduced ATP, and produced mitochondrial and synaptic ultrastructural deficits. IL-17A overexpression further worsened mitophagy and behavior, whereas rapamycin restored both. Conditional deletion of CD8α in γδ T cells reduced brain γδ T17 infiltration, lowered hippocampal IL-17A, rescued mitophagy and synapses, and improved behavior. Arketamine normalized dysbiosis and barrier markers, curtailed γδ T cell trafficking, decreased hippocampal IL-17A, restored mitophagy, and alleviated depression-like behavior in both sexes. These findings delineate a stress-responsive microbiota-γδ T cell-IL-17A pathway that compromises hippocampal mitophagy and identify arketamine as a candidate modulator of this axis, nominating mitophagy and γδ T cell trafficking as translational targets.

Background: Peripheral consequences following traumatic brain injury (TBI) are characterized by both systemic inflammatory responses and autonomic dysregulation. One of the main immune regulatory organs, the spleen, shows high interaction with the brain which is controlled by both circulating mediators as well as autonomic fibers targeting splenic immune cells. The brain-spleen axis does not function as a one-way street, it also shows reciprocal effects where the spleen affects neuroinflammatory and cognitive functions post injury. To date, systemic and splenic inflammatory responses are measured by cells or mediators located in circulation. Nevertheless, most of the signaling and inflammation post injury takes place in the organs.

Methods: We set out to investigate the early (3 h) signaling landscape in the spleen following a moderate severity closed head injury model to wild-type animals aged p60-90. Using phospho-proteomic signaling approaches, immunofluorescence stainings, Enzyme-Linked Immunosorbent Assay (ELISA), super-resolution microscopy and single mRNA in situ hybridization we investigated novel molecular and cellular players in the spleen involved in immune modulation after a head injury.

Results: Based on the signaling signature, we found a rapid influx of basophil granulocytes towards the spleen, via a recruitment mechanism that includes CXCL1 expressed by B-cells and dendritic cells (DCs). The basophils in turn seem to activate B cells and dendritic cells via the IL-13/IL-13Ra1 signaling pathway and enhance protein translation through the long non-coding RNA NORAD. The early recruitment of basophils and subsequent activation of B cells and DCs, is short lived and sets at 3dpi. Interestingly, the rapid recruitment of basophils is inhibited by ethanol intoxication in TBI, with a subsequent prevention of IL-13Ra phosphorylation and NORAD increase in B-cells and DCs.

Conclusion: Basophils recruitment to the spleen may serve as an early mediator of systemic inflammatory responses to TBI with potential implications for research on biomarkers and therapeutic targets.