Inhibition of Perforin-Mediated Neurotoxicity Attenuates Neurological Deficits After Ischemic Stroke

Abstract

Perforin-mediated cytotoxicity plays a crucial role in microbial defense, tumor surveillance, and primary autoimmune disorders. However, the contribution of the cytolytic protein perforin to ischemia-induced secondary tissue damage in the brain has not been fully investigated. Here, we examined the kinetics and subpopulations of perforin-positive cells and then evaluated the direct effects of perforin-mediated cytotoxicity on outcomes after ischemic stroke. Using flow cytometry, we showed that perforin+CD45+ immune cells could be detected at 12 h and that the percentage of these cells increased largely until on day 3 and then significantly declined on day 7. Surprisingly, the percentage of Perforin+CD45+ cells also unexpectedly increased from day 7 to day 14 after ischemic stroke in Perforin1-EGFP transgenic mice. Our results suggested that Perforin+CD45+ cells play vital roles in the ischemic brain at early and late stages and further suggested that Perforin+CD45+ cells are a heterogeneous population. Surprisingly, in addition to CD8+ T cells, NK cells, and NKT cells, central nervous system (CNS)-resident immune microglia, which are first triggered and activated within minutes after ischemic stroke in mice, also secreted perforin during ischemic brain injury. In our study, the percentage of perforin+ microglia increased from 12 h after ischemic stroke, increased largely until on day 3 after ischemic stroke, and then moderately declined from days 3 to 7. Intriguingly, the percentage of perforin+ microglia also dramatically increased from days 7 to 14 after ischemic stroke. Furthermore, compared with wild-type littermates, Perforin 1–/– mice exhibited significant increases in the cerebral infarct volume, neurological deficits, and neurogenesis and inhibition of neurotoxic astrogliosis. Interestingly, the number of CD45+CD3+ T cells was significantly decreased in Perforin 1–/– mice compared with their wild-type littermates, especially the number of γδ T cells. In addition, Perforin 1–/– mice had lower levels of IL-17 than their wild-type littermates. Our results identified a critical function of perforin-mediated neurotoxicity in the ischemic brain, suggesting that targeting perforin-mediated neurotoxicity in brain-resident microglia and invading perforin+CD45+ immune cells may be a potential strategy for the treatment of ischemic stroke.

Assessing the role of T cells in response to retinal injury to uncover new therapeutic targets for the treatment of retinal degeneration

“…These data suggest CD8 T cells act via the Prf1 pathway to impair retinal and BRB repair mechanisms. Recently, the Prf1 pathway has also been associated with different CNS diseases spanning from the eye to the brain, such as choroidal neovascularization in AMD patients, but also in mouse models of experimental stroke [ 107 ], TBI [ 33 ], Parkinson's [ 108 ], and Alzheimer’s diseases [ 109 ]. Relevant to our findings, Matsubara et al [ 110 ] demonstrated that retinal degeneration, either due to aging or pathological conditions associated with AMD, is worsened by an increased presence of Prf1 immunoreactive cells in the outer retina.…”

Neuroglia Cells Transcriptomic in Brain Development, Aging and Neurodegenerative Diseases

“…Perforin-2/macrophage-expressed protein 1 is one of the oldest membrane attack complexes of complement [188]. In ischemic stroke the number of macrophages expressing perforin increase largely until day 3 after stroke, and then moderately decline [189].…”

The role of circadian clock in astrocytes: From cellular functions to ischemic stroke therapeutic targets

“…Therefore, reduced adenosine triphosphate production (ATP) production and sodium–potassium pump malfunction lead to mitochondrial dysfunction and bioenergetic collapse ( Amantea and Bagetta, 2017 ). The pathological processes described above lead to the deterioration of membrane ion gradients, calcium influx, and increased release of amino acids, including toxic concentrations of the excitatory neurotransmitter glutamate and aspartate ( Globus et al, 1988 ; Pan et al, 2021 ). In the acute phase following ischemic injury, excessive release of glutamate, and dramatic dysfunction of glutamate transporters in astrocytes, accumulation of glutamate cause excitotoxicity-mediated neuronal apoptosis death ( Lai et al, 2014 ; Shen et al, 2022 ).…”