Elsevier

Brain, Behavior, and Immunity

Volume 79, July 2019, Pages 174-185
Brain, Behavior, and Immunity

Rh-IFN-α attenuates neuroinflammation and improves neurological function by inhibiting NF-κB through JAK1-STAT1/TRAF3 pathway in an experimental GMH rat model

https://doi.org/10.1016/j.bbi.2019.01.028Get rights and content

Highlights

  • Rh-IFN-α improves neurological behavior and attenuates post hemorrhagic hydrocephalus after GMH.

  • Rh-IFN-α inhibits neuroinflammation after GMH.

  • Anti-inflammatory effect of Rh-IFN-α is mediated through IFNAR/JAK1-STAT1/TRAF3/ NF-Κb pathway after GMH.

Abstract

Neuroinflammation occurs after germinal matrix hemorrhage (GMH) and induces secondary brain injury. Interferon-α (IFN-α) has been shown to exert anti-inflammatory effects in infectious diseases via activating IFNAR and its downstream signaling. We aimed to investigate the anti-inflammatory effects of Recombinant human IFN-α (rh-IFN-α) and the underlying mechanisms in a rat GMH model. Two hundred and eighteen P7 rat pups of both sexes were subjected to GMH by an intraparenchymal injection of bacterial collagenase. Rh-IFN-α was administered intraperitoneally. Small interfering RNA (siRNA) of IFNAR, and siRNA of tumor necrosis factor receptor associated factor 3 (TRAF3) were administered through intracerebroventricular (i.c.v.) injections. JAK1 inhibitor ruxolitinib was given by oral lavage. Post-GMH evaluation included neurobehavioral function, Nissl staining, Western blot analysis, and immunofluorescence. Our results showed that endogenous IFN-α and phosphorylated IFNAR levels were increased after GMH. Administration of rh-IFN-α improved neurological functions, attenuated neuroinflammation, inhibited microglial activation, and ameliorated post-hemorrhagic hydrocephalus after GMH. These observations were concomitant with IFNAR activation, increased expression of phosphorylated JAK1, phosphorylated STAT1 and TRAF3, and decreased levels of phosphorylated NF-κB, IL-6 and TNF-α. Specifically, knockdown of IFNAR, JAK1 and TRAF3 abolished the protective effects of rh-IFN-α. In conclusion, our findings demonstrated that rh-IFN-α treatment attenuated neuroinflammation, neurological deficits and hydrocephalus formation through inhibiting microglial activation after GMH, which might be mediated by IFNAR/JAK1-STAT1/TRAF3/NF-κB signaling pathway. Rh-IFN-α may be a promising therapeutic agent to attenuate brain injury via its anti-inflammatory effect.

Introduction

Germinal matrix hemorrhage (GMH) is a devastating neonatal stroke, of which the complications include neuroinflammation, hydrocephalus, primary and secondary brain injury and developmental delay (Koschnitzky et al., 2018). Among all of the complications, the activation of inflammatory cascades could be the main contributing factor of a series of post-hemorrhagic consequences, such as long term morphological and functional impairment (Zhang et al., 2018, Feng et al., 2017). Therefore, inhibition of inflammatory response is critically important at the early stage after GMH.

Microglia are resident immune cells in the central nervous system (CNS) (Tang et al., 2017). Following GMH, microglia are activated immediately and release proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), leading to secondary brain injury (Brouwer et al., 2016). Thus, treatments focused on reducing proinflammatory cytokines by inhibiting microglia could be potentially important in attenuating neuroinflammation after GMH.

Interferon-α (IFN-α), one of type one interferons, can access the CNS to modulate microglial function in innate immune response (Owens et al., 2014). Binding to its receptor, IFN-α receptor (IFNAR), can activate the receptor-associated protein tyrosine kinases Janus kinases 1 (JAK1), which phosphorylates the latent cytoplasmic transcription factor signal transducer and activator of transcription 1 (STAT1). Currently, a number of studies have reported several pathways that link IFN-α with IFN-regulatory factors (IRF), toll-like receptors (TLRs), phosphatidylinositol 3 kinase (PI3K) and mitogen-activated protein kinases (MAPK) (Wang et al., 2010). On the other hand, the tumor necrosis factor receptor associated factor 3 (TRAF3) molecules are largely involved in signaling by a variety of adaptive and innate immune responses. TRAF3 signaling pathways typically lead to the activation of nuclear factor-κB (NF-κB) and IRFs, which is also related to immunomodulation (Tang et al., 2018). Although both IFN-α and TRAF3 were reported to interact with IRFs after inflammatory activation, it is still unknown whether TRAF3 is a downstream mediator of IFN-α in exerting its anti-inflammatory effect.

Therefore, based on the above mentioned evidence, we hypothesized that rh-IFN-α treatment would attenuate neuroinflammation after GMH by suppressing microglial activation and consequently reduce the secretion of proinflammotory cytokines, improve neurological function in the short and long term and ameliorate posthemorrhagic hydrocephalus, and that these beneficial effects may be mediated by JAK1-STAT1/TRAF3/NF-κB signaling (Fig. 1).

Section snippets

Animals

All experimental procedures were approved by the Institutional Animal Care and Use Committee at Loma Linda University. All studies were conducted in accordance with the United States Public Health Service’s Policy on Humane Care and Use of Laboratory Animals and reported according to the ARRIVE guidelines. Two hundred and eighteen P7 Sprague-Dawley neonatal pups (weight = 12–14 g, Harlan, Livermore, CA) were randomly divided into Sham (n = 36) and GMH (n = 182) groups. All pups were housed with

Endogenous IFN-α and phosphorylated IFNAR were upregulated after GMH.

Western blot results showed that there was a significant difference in the expression of endogenous IFN-α on the 3rd (df = 25, P < 0.001), 5th (df = 25, P < 0.001) and 7th (df = 25, P < 0.001) day after GMH (Fig. 2A and B). The expression of phosphorylated IFNAR increased slowly from the 3rd day (df = 25, p < 0.001), peaked on the 5th day (df = 25, p < 0.001), and declined on the 7th day after GMH (p = 0.003, Fig. 2A and C). No changes were observed in the expression of IFNAR (Fig. 2A). Double

Discussion

The incidence of GMH is approximately 50% in preterm infants between 24 and 30 weeks of gestation (Lekic et al., 2012 Jul, Koschnitzky et al., 2018). The newborn rat has neurodevelopmental similarities to preterm humans at 24–26 weeks. A previously publication also indicated that P7 Sprague-Dawley rats are comparable to 32 weeks of human gestational age (Lekic et al., 2015). GMH is a devastating neonatal stroke characterized as neuroinflammation, hydrocephalus, primary and secondary brain

Conflict of interest

The authors declare no competing financial interests.

Acknowledgments

This study was supported by an R21 grant from the National Institutes of Health (NS101284) to Dr. Jiping Tang, Natural Science Fund of China (NO. 81301098) to Dr. Peng Li and Traumatic research center of Yunnan Province (2016NS285) to Dr. Gang Zhao.

References (38)

  • L. Wang et al.

    Indirect inhibition of Toll-like receptor and type I interferon responses by ITAM-coupled receptors and integrins

    Immunity

    (2010)
  • J. Wei et al.

    Alpha/beta interferon receptor deficiency in mice significantly enhances susceptibility of the animals to pseudorabies virus infection

    Vet Microbiol.

    (2017)
  • A.A. Agyemang et al.

    Cerebellar exposure to cell-free hemoglobin following preterm intraventricular hemorrhage: causal in cerebellar damage?

    Transl. Stroke Res.

    (2017)
  • H. Ahnstedt et al.

    The importance of considering sex differences in translational stroke research

    Transl. Stroke Res.

    (2016)
  • L. Alammar et al.

    Simian immunodeficiency virus infection in the brain and lung leads to differential type I IFN signaling during acute infection

    J. Immunol.

    (2011)
  • S.M. Brendecke et al.

    How type I interferons shape myeloid cell function in CNS autoimmunity

    J. Leukoc. Biol.

    (2012)
  • M.J. Brouwer et al.

    Effects of posthemorrhagic ventricular dilatation in the preterm infant on brain volumes and white matter diffusion variables at term-equivalent age

    J. Pediatr.

    (2016)
  • G. Dang et al.

    Early erythrolysis in the hematoma after experimental intracerebral hemorrhage

    Transl. Stroke Res.

    (2017)
  • J.E. Faber et al.

    Sex differences in the cerebral collateral circulation

    Transl. Stroke Res.

    (2017)
  • Cited by (37)

    • Secukinumab attenuates neuroinflammation and neurobehavior defect via PKCβ/ERK/NF-κB pathway in a rat model of GMH

      2023, Experimental Neurology
      Citation Excerpt :

      Therefore, more studies are urgently needed to investigate innovative therapeutic modalities. The activation of inflammation cascades plays a critical role during the pathological process and aggravates neurobehavioral deficits after GMH (Li et al., 2019; Zhang et al., 2018; Feng et al., 2019). Meanwhile, some inflammatory markers can be seen elevated in the severely hemorrhagic brain (Supramaniam et al., 2013).

    • Remifentanil alleviates hypoxic-ischemic brain damage-induced cognitive impairment via BACH1

      2022, Neuroscience Letters
      Citation Excerpt :

      In the present study, we found that TRAF3 is a downstream gene of BACH1 in HIBD. Recombinant human interferon-α attenuated neuroinflammation and improved neurological function by inhibiting NF-κB through TRAF3 in a rat model with germinal matrix hemorrhage [32]. TRAF3 siRNA reversed neuronal loss and improved neurological deficits in mice with subarachnoid hemorrhage, and prevented cell death in primary neurons by blocking the NF-κB pathway [33].

    • Priming of microglia by type II interferon is lasting and resistant to modulation by interleukin-10 in situ

      2022, Journal of Neuroimmunology
      Citation Excerpt :

      Although many genes are induced by type I and type II interferons in a similar manner, these differences in microglial responsiveness might rely on the direct activation of STAT1 targets by IFN-γ, which are associated with lasting priming effects of this cytokine (Barrat et al., 2019; Kang et al., 2019). Moreover, type I interferons present a bimodal function in the brain and are frequently involved with negative regulation of pro-inflammatory signaling (Blank and Prinz, 2017; Li et al., 2019). In this regard, we also investigated if priming of microglia by type I interferons could prevent the inflammatory neurotoxicity induced by simultaneous exposure to IFN-γ and LPS.

    • HLY78 protects blood-brain barrier integrity through Wnt/β-catenin signaling pathway following subarachnoid hemorrhage in rats

      2020, Brain Research Bulletin
      Citation Excerpt :

      The number of their forelimb or hindlimb fell through one of the openings in the grid was recorded. The spatial memory retention of rats was evaluated by Morris water maze test, as previously described (Li et al., 2019). Briefly, in the early five days, rats were released from four different quadrants of a circular pool to let them find a visible platform above the water level within 60 s. On the sixth day, the platform was removed, and the rats were allowed to probe freely for 60 s. Swim path, swim distance, escape latency, and probe quadrant duration was recorded by a computerized tracking system (Noldus Ethovision; Noldus, Tacoma, WA, USA).

    View all citing articles on Scopus
    1

    These authors contributed equally to this work.

    View full text