Mitochondrial ferritin upregulation by deferiprone reduced neuronal ferroptosis and improved neurological deficits via NDRG1/Yap pathway in a neonatal rat model of germinal matrix hemorrhage.

Ferroptosis contributes to brain injury after germinal matrix hemorrhage (GMH). Mitochondrial ferritin (FTMT), a novel mitochondrial outer membrane protein, reduces oxidative stress in neurodegenerative diseases. In vitro, Deferiprone has been shown to upregulate FTMT. However, the effects of FTMT upregulation by Deferiprone on neuronal ferroptosis after GMH and its underlying mechanism has not been investigated. In our study, 389 Sprague-Dawley rat pups of postnatal day 7 were used to establish a collagenase-induced GMH model and an iron-overload model of intracerebral FeCl2 injection. The brain expressions of FTMT, N-myc downstream-regulated gene-1 (NDGR1), Yes-associated protein (YAP), ferroptosis-related molecules including transferrin receptor (TFR) and acyl-CoA synthase long-chain family member 4 (ACSL4) were increased after GMH. FTMT agonist Deferiprone improved neurological deficits and hydrocephalus after GMH. Deferiprone or Adenovirus-FTMT enhanced YAP phosphorylation at the Ser127 site and attenuated ferroptosis, which was reversed by NDRG1 CRISPR Knockout. Iron overload induced neuronal ferroptosis and neurological deficits, which were improved by YAP CRISPR Knockout. Collectively, FTMT upregulation by Deferiprone reduced neuronal ferroptosis and neurological deficits via the NDRG1/YAP signaling pathway after GMH. Deferiprone may serve as a potential non-invasive treatment for GMH patients.

PEDF-34 attenuates neurological deficit and suppresses astrocyte-dependent neuroinflammation by modulating astrocyte polarization via 67LR/JNK/STAT1 signaling pathway after subarachnoid hemorrhage in rats.

BACKGROUND: Reactive astrocytes participate in various pathophysiology after subarachnoid hemorrhage (SAH), including neuroinflammation, glymphatic-lymphatic system dysfunction, brain edema, BBB disruption, and cell death. Astrocytes transform into two new reactive phenotypes with changed morphology, altered gene expression, and secretion profiles, termed detrimental A1 and beneficial A2. This study investigates the effect of 67LR activation by PEDF-34, a PEDF peptide, on neuroinflammation and astrocyte polarization after the experimental SAH. METHODS: A total of 318 male adult Sprague-Dawley rats were used in experiments in vivo, of which 272 rats were subjected to the endovascular perforation model of SAH and 46 rats underwent sham surgery. 67LR agonist (PEDF-34) was administrated intranasally 1 h after SAH. 67LR-specific inhibitor (NSC-47924) and STAT1 transcriptional activator (2-NP) were injected intracerebroventricularly 48 h before SAH. Short- and long-term neurological tests, brain water content, immunostaining, Nissl staining, western blot, and ELISA assay were performed. In experiments in vitro, primary astrocyte culture with hemoglobin (Hb) stimulation was used to mimic SAH. The expression of the PEDF-34/67LR signaling pathway and neuro-inflammatory cytokines were assessed using Western blot, ELISA, and immunohistochemistry assays both in vivo and in vitro. RESULTS: Endogenous PEDF and 67LR expressions were significantly reduced at 6 h after SAH. 67LR was expressed in astrocytes and neurons. Intranasal administration of PEDF-34 significantly reduced brain water content, pro-inflammatory cytokines, and short-term and long-term neurological deficits after SAH. The ratio of p-JNK/JNK and p-STAT1/STAT1 and the expression of CFB and C3 (A1 astrocytes marker), significantly decreased after PEDF-34 treatment, along with fewer expression of TNF-α and IL-1ß at 24 h after SAH. However, 2-NP (STAT1 transcriptional activator) and NSC-47924 (67LR inhibitor) reversed the protective effects of PEDF-34 in vivo and in vitro by promoting A1 astrocyte polarization with increased inflammatory cytokines. CONCLUSION: PEDF-34 activated 67LR, attenuating neuroinflammation and inhibiting astrocyte A1 polarization partly via the JNK/STAT1 pathway, suggesting that PEDF-34 might be a potential treatment for SAH patients.

Mitochondrial ferritin upregulation reduced oxidative stress and blood-brain-barrier disruption by maintaining cellular iron homeostasis in a neonatal rat model of germinal matrix hemorrhage.

Germinal matrix hemorrhage (GMH) is a devasting neurological disease in premature newborns. After GMH, brain iron overload associated with hemoglobin degradation contributed to oxidative stress, causing disruption of the already vulnerable blood-brain barrier (BBB). Mitochondrial ferritin (FTMT), a novel mitochondrial outer membrane protein, is crucial in maintaining cellular iron homeostasis. We aimed to investigate the effect of FTMT upregulation on oxidative stress and BBB disruption associated with brain iron overload in rats. A total of 222 Sprague-Dawley neonatal rat pups (7 days old) were used to establish a collagenase-induced GMH model and an iron-overload model of intracerebral FeCl2 injection. Deferiprone was administered via gastric lavage 1 h after GMH and given daily until euthanasia. FTMT CRISPR Knockout and adenovirus (Ad)-FTMT were administered intracerebroventricularly 48 h before GMH and FeCl2 injection, respectively. Neurobehavioral tests, immunofluorescence, Western blot, Malondialdehyde measurement, and brain water content were performed to evaluate neurobehavior deficits, oxidative stress, and BBB disruption, respectively. The results demonstrated that brain expressions of iron exporter Ferroportin (FPN) and antioxidant glutathione peroxidase 4 (GPX4) as well as BBB tight junction proteins including Claudin-5 and Zona Occulta (ZO)-1 were found to be decreased at 72 h after GMH. FTMT agonist Deferiprone attenuated oxidative stress and preserved BBB tight junction proteins after GMH. These effects were partially reversed by FTMT CRISPR Knockout. Iron overload by FeCl2 injection resulted in oxidative stress and BBB disruption, which were improved by Ad-FTMT mediated FTMT overexpression. Collectively, FTMT upregulation is neuroprotective against brain injury associated with iron overload. Deferiprone reduced oxidative stress and BBB disruption by maintaining cellular iron homeostasis partially by the upregulating of FTMT after GMH. Deferiprone may be an effective treatment for patients with GMH.

Fractalkine Enhances Hematoma Resolution and Improves Neurological Function via CX3CR1/AMPK/PPARγ Pathway After GMH.

BACKGROUND: Hematoma clearance has been a proposed therapeutic strategy for hemorrhagic stroke. This study investigated the impact of CX3CR1 (CX3C chemokine receptor 1) activation mediated by r-FKN (recombinant fractalkine) on hematoma resolution, neuroinflammation, and the underlying mechanisms involving AMPK (AMP-activated protein kinase)/PPARγ (peroxisome proliferator-activated receptor gamma) pathway after experimental germinal matrix hemorrhage (GMH). METHODS: A total of 313 postnatal day 7 Sprague Dawley rat pups were used. GMH was induced using bacterial collagenase by a stereotactically guided infusion. r-FKN was administered intranasally at 1, 25, and 49 hours after GMH for short-term neurological evaluation. Long-term neurobehavioral tests (water maze, rotarod, and foot-fault test) were performed 24 to 28 days after GMH with the treatment of r-FKN once daily for 7 days. To elucidate the underlying mechanism, CX3CR1 CRISPR, or selective CX3CR1 inhibitor AZD8797, was administered intracerebroventricularly 24 hours preinduction of GMH. Selective inhibition of AMPK/PPARγ signaling in microglia via intracerebroventricularly delivery of liposome-encapsulated specific AMPK (Lipo-Dorsomorphin), PPARγ (Lipo-GW9662) inhibitor. Western blot, Immunofluorescence staining, Nissl staining, Hemoglobin assay, and ELISA assay were performed. RESULTS: The brain expression of FKN and CX3CR1 were elevated after GMH. FKN was expressed on both neurons and microglia, whereas CX3CR1 was mainly expressed on microglia after GMH. Intranasal administration of r-FKN improved the short- and long-term neurobehavioral deficits and promoted M2 microglia polarization, thereby attenuating neuroinflammation and enhancing hematoma clearance, which was accompanied by an increased ratio of p-AMPK (phosphorylation of AMPK)/AMPK, Nrf2 (nuclear factor erythroid 2-related factor 2), PPARγ, CD36 (cluster of differentiation 36), CD163 (hemoglobin scavenger receptor), CD206 (the mannose receptor), and IL (interleukin)-10 expression, and decreased CD68 (cluster of differentiation 68), IL-1ß, and TNF (tumor necrosis factor) α expression. The administration of CX3CR1 CRISPR or CX3CR1 inhibitor (AZD8797) abolished the protective effect of FKN. Furthermore, selective inhibition of microglial AMPK/PPARγ signaling abrogated the anti-inflammation effects of r-FKN after GMH. CONCLUSIONS: CX3CR1 activation by r-FKN promoted hematoma resolution, attenuated neuroinflammation, and neurological deficits partially through the AMPK/PPARγ signaling pathway, which promoted M1/M2 microglial polarization. Activating CX3CR1 by r-FKN may provide a promising therapeutic approach for treating patients with GMH.

The Guidewire-assisted Drainage Catheter Placement in Chronic Subdural Hematoma.

Background: Chronic subdural hematoma (cSDH) is a common neurosurgical pathology associated with older age. The burr hole drainage is a predominant technique with a lower incidence of recurrence and morbidity. The blind placement of the subdural drain could result in intracerebral hemorrhage. This paper describes a simple and reliable technique for drainage catheter placement in cSDH to reduce intracerebral hemorrhage. Methods: Forty-nine consecutive patients with cSDH were treated with The Guidewire-assisted Drainage Catheter Placement Technique between July 2019 and June 2021. Epidemiological, clinical and radiographical data were collected and reviewed. The operative technique consists of an angular guidewire tip and catheter. Under the navigation of the guidewire, the catheter is inserted into the subdural space and the length of catheter remaining in the subdural space was 4-5 cm. The catheter was tunneled subcutaneously and fixed at the point where it emerged from the scalp. Results: Forty-nine consecutive patients underwent 55 The Guidewire-assisted Drainage Catheter Placement. The gender distribution was 37 men and 12 women. The mean age was 69.3 years. The patients presented with headache (31 patients), weakness of limbs (28 patients), speech disturbances (7 patients), and Altered behavior (6 patients). Neither intracerebral hemorrhages nor post-operative seizure occurred. Forty-seven patients were improved after the operation. The recurrence occurred in one patient. Conclusions: The Guidewire-assisted Drainage Catheter Placement Technique is a reliable method for the insertion of a subdural catheter to evacuate of the Chronic Subdural Hematoma, and is associated with an extremely low risk to cortical structures and cerebral veins.