CX3CL1 Recruits NK Cells Into the Central Nervous System and Aggravates Brain Injury of Mice Caused by Angiostrongylus cantonensis Infection

The Innate Immune Sensor Zbp1 Mediates Central Nervous System Inflammation Induced by Angiostrongylus Cantonensis by Promoting Macrophage Inflammatory Phenotypes

Angiostrongylus cantonensis (AC) is the leading cause of eosinophilic meningoencephalitis worldwide. The neuroimmune interactions between peripheral and central immune systems in angiostrongyliasis remain unclear. In this study, significant infiltration of eosinophils, myeloid cells, macrophages, neutrophils, and Ly6C monocytes is observed in the brains of AC-infected mice, with macrophages being the most abundant. RNA-seq and SMART-seq analysis of pattern recognition receptor (PRR) and DNA sensor gene sets revealed a marked increase in Z-DNA binding protein 1 (Zbp1) expression in infected mice. Confocal microscopy, RT-qPCR, western blotting, and immunohistochemistry further confirmed that Zbp1 is specifically upregulated in macrophages and microglia. Using Zbp1-knockout mice and flow cytometry, it is found that knockout of Zbp1 enhanced lymphocyte infiltration and natural killer cell cytotoxicity, modulating the immune microenvironment in the central nervous system (CNS) during AC infection. Mechanistically, it is revealed that in macrophage Zbp1 directly binds to receptor-interacting protein 3 (RIP3) to promote its phosphorylation, subsequently facilitating the phosphorylation of mixed lineage kinase domain-like protein (Mlkl). The activated Zbp1-pRIP3-pMlkl axis leads to necroptosis and upregulates pro-inflammatory cytokines including TNF-α, IL-1α, CXCL9, CXCL10 in macrophages, which recruits and activates immune cells. These findings offer new insights into the pathogenic mechanisms of angiostrongyliasis and suggest potential therapeutic strategies.

Innate lymphoid cells in neuroinflammation

Innate lymphoid cells (ILCs) are largely tissue-resident cells that participate in the maintenance of tissue homeostasis and react early to inflammatory events. Mature ILCs are divided into three major groups based on the transcription factors required for their development and function. Under physiological conditions, ILCs are present within the choroid plexus and meninges while the CNS parenchyma is almost devoid of these cells. However, pathological conditions such as autoimmune neuroinflammation and viral infections of the CNS result in the infiltration of ILCs into parenchyma. In this article, we provide an overview of the involvement and function of the ILCs within the CNS during physiological conditions and in infections, autoimmune diseases, neurodegeneration, and injury.

Natural killer cells in the central nervous system

Natural killer (NK) cells are essential components of the innate lymphoid cell family that work as both cytotoxic effectors and immune regulators. Accumulating evidence points to interactions between NK cells and the central nervous system (CNS). Here, we review the basic knowledge of NK cell biology and recent advances in their roles in the healthy CNS and pathological conditions, with a focus on normal aging, CNS autoimmune diseases, neurodegenerative diseases, cerebrovascular diseases, and CNS infections. We highlight the crosstalk between NK cells and diverse cell types in the CNS and the potential value of NK cells as novel therapeutic targets for CNS diseases. Video Abstract.

Thromboinflammation in Brain Ischemia: Recent Updates and Future Perspectives

Despite decades of promising preclinical validation and clinical translation, ischemic stroke still remains as one of the leading causes of death and disability worldwide. Within its complex pathophysiological signatures, thrombosis and inflammation, that is, thromboinflammation, are highly interconnected processes leading to cerebral vessel occlusion, inflammatory responses, and severe neuronal damage following the ischemic event. Hence, we here review the most recent updates on thromboinflammatory-dependent mediators relevant after stroke focusing on recent discoveries on platelet modulation, a potential regulation of the innate and adaptive immune system in thromboinflammation, utterly providing a thorough up-to-date overview of all therapeutic approaches currently undergoing clinical trial.