Dataset Information

Rh-CSF1 attenuates neuroinflammation via the CSF1R/PLCG2/PKCε pathway in a rat model of neonatal HIE.

ABSTRACT:

Background

Hypoxic-ischemic encephalopathy (HIE) is a life-threatening cerebrovascular disease. Neuroinflammation plays an important role in the pathogenesis of HIE, in which microglia are key cellular mediators in the regulation of neuroinflammatory processes. Colony-stimulating factor 1 (CSF1), a specific endogenous ligand of CSF1 receptor (CSF1R), is crucial in microglial growth, differentiation, and proliferation. Recent studies showed that the activation of CSF1R with CSF1 exerted anti-inflammatory effects in a variety of nervous system diseases. This study aimed to investigate the anti-inflammatory effects of recombinant human CSF1 (rh-CSF1) and the underlying mechanisms in a rat model of HIE.

Methods

A total of 202 10-day old Sprague Dawley rat pups were used. HI was induced by the right common carotid artery ligation with subsequent exposure of 2.5-h hypoxia. At 1 h and 24 h after HI induction, exogenous rh-CSF1 was administered intranasally. To explore the underlying mechanism, CSF1R inhibitor, BLZ945, and phospholipase C-gamma 2 (PLCG2) inhibitor, U73122, were injected intraperitoneally at 1 h before HI induction, respectively. Brain infarct area, brain water content, neurobehavioral tests, western blot, and immunofluorescence staining were performed.

Results

The expressions of endogenous CSF1, CSF1R, PLCG2, protein kinase C epsilon type (PKCε), and cAMP response element-binding protein (CREB) were gradually increased after HIE. Rh-CSF1 significantly improved the neurological deficits at 48 h and 4 weeks after HI, which was accompanied by a reduction in the brain infarct area, brain edema, brain atrophy, and neuroinflammation. Moreover, activation of CSF1R by rh-CSF1 significantly increased the expressions of p-PLCG2, p-PKCε, and p-CREB, but inhibited the activation of neutrophil infiltration, and downregulated the expressions of IL-1β and TNF-α. Inhibition of CSF1R and PLCG2 abolished these neuroprotective effects of rh-CSF1 after HI.

Conclusions

Our findings demonstrated that the activation of CSF1R by rh-CSF1 attenuated neuroinflammation and improved neurological deficits after HI. The anti-inflammatory effects of rh-CSF1 partially acted through activating the CSF1R/PLCG2/PKCε/CREB signaling pathway after HI. These results suggest that rh-CSF1 may serve as a potential therapeutic approach to ameliorate injury in HIE patients.

SUBMITTER: Hu X

PROVIDER: S-EPMC7285566 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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Publications

Rh-CSF1 attenuates neuroinflammation via the CSF1R/PLCG2/PKCε pathway in a rat model of neonatal HIE.

Hu Xiao X Li Shirong S Doycheva Desislava Met DM Huang Lei L Lenahan Cameron C Liu Rui R Huang Juan J Xie Shucai S Tang Jiping J Zuo Gang G Zhang John H JH

Journal of neuroinflammation 20200610 1

<h4>Background</h4>Hypoxic-ischemic encephalopathy (HIE) is a life-threatening cerebrovascular disease. Neuroinflammation plays an important role in the pathogenesis of HIE, in which microglia are key cellular mediators in the regulation of neuroinflammatory processes. Colony-stimulating factor 1 (CSF1), a specific endogenous ligand of CSF1 receptor (CSF1R), is crucial in microglial growth, differentiation, and proliferation. Recent studies showed that the activation of CSF1R with CSF1 exerted a ...[more]

PMID: 32522286

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Project description:BACKGROUND:Neuroinflammation plays an important role in pathogenesis of germinal matrix hemorrhage (GMH). Neurotrophin-4 (NT-4) is a member of the neurotrophin family and interacts with the tropomyosin receptor kinase B (TrkB). NT-4 has been shown to confer neuroprotective effects following cerebral ischemia. We aimed to investigate the neuroprotective function of NT-4-TrkB signaling, as well as its downstream signaling cascade phosphatidylinositol-3-kinases (PI3K)/protein kinase B (Akt)/forkhead box protein O1 (FoxO1), following GMH in neonatal rats. METHODS:GMH was induced by intraparenchymal injection of bacterial collagenase (0.3?U) in P7 rat pups. A total of 163 pups were used in this study. Recombinant human NT-4 was administered intranasally at 1?h after the collagenase injection. The selective TrkB antagonist ANA-12, selective PI3K inhibitor LY294002, and FoxO1 activating CRISPR were administered intracerebroventricularly at 24?h prior to NT-4 treatment to investigate the underlying mechanism. Short-term and long-term neurobehavioral assessments, immunofluorescence staining, Nissl's staining, and Western blot were performed. RESULTS:Expression of phosphorylated TrkB increased after GMH, reaching the peak level at day 3 after hemorrhage. TrkB receptors were observed on neurons, microglia, and astrocytes. The administration of rh-NT-4 induced phosphorylation of TrkB, expression of PI3K, and phosphorylation of Akt. Meanwhile, it decreased FoxO1 and IL-6 levels. Selective inhibition of TrkB/PI3K/Akt signaling in microglia increased the expression levels of FoxO1 and pro-inflammatory cytokines. FoxO1 activating CRISPR increased the expression of IL-6, suggesting that FoxO1 might be a potential inducer of pro-inflammatory factors. These results suggested that PI3K/Akt/FoxO1 signaling may be the downstream pathway of activation of TrkB. The rat pups treated with rh-NT-4 performed better than vehicle-treated animals in both short-term and long-term behavioral tests. CONCLUSION:These data showed that rh-NT-4 reduced the expression levels of pro-inflammatory cytokines, improved neurological function, attenuated neuroinflammation, and thereby mitigated post-hemorrhagic hydrocephalus after GMH by TrkB/PI3K/Akt/FoxO1 pathway. These results indicated that rh-NT-4 could be a promising therapeutic strategy to ameliorate neuroinflammation and hydrocephalus after GMH or other similar brain injuries.

Dataset Information

Rh-CSF1 attenuates neuroinflammation via the CSF1R/PLCG2/PKCε pathway in a rat model of neonatal HIE.

Background

Methods

Results

Conclusions

Publications

Rh-CSF1 attenuates neuroinflammation via the CSF1R/PLCG2/PKCε pathway in a rat model of neonatal HIE.

Similar Datasets

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