Menaquinone-4 attenuates ferroptosis by upregulating DHODH through activation of SIRT1 after subarachnoid hemorrhage.

BACKGROUND: Menaquinone-4(MK-4), the isoform of vitamin K2 in the brain, exerts neuroprotective effects against a variety of central nervous system disorders. This study aimed to demonstrate the anti-ferroptosis effects of MK-4 in neurons after SAH. METHODS: A subarachnoid hemorrhage (SAH) model was prepared by endovascular perforation in mice. In vitro hemoglobin stimulation of primary cortical neurons mimicked SAH. MK-4, Brequinar (BQR, DHODH inhibitor), and Selisistat (SEL, SIRT1 inhibitor) were administered, respectively. Subsequently, WB, immunofluorescence was used to determine protein expression and localization, and transmission electron microscopy was used to observe neuronal mitochondrial structure while other indicators of ferroptosis were measured. RESULTS: MK-4 treatment significantly upregulated the protein levels of DHODH; decreased GSH, PTGS2, NOX1, ROS, and restored mitochondrial membrane potential. Meanwhile, MK-4 upregulated the expression of SIRT1 and promoted its entry into the nucleus. BQR or SEL partially abolished the protective effect of MK-4 on, neurologic function, and ferroptosis. CONCLUSIONS: Taken together, our results suggest that MK-4 attenuates ferroptosis after SAH by upregulating DHODH through the activation of SIRT1.

P38-DAPK1 axis regulated LC3-associated phagocytosis (LAP) of microglia in an in vitro subarachnoid hemorrhage model.

BACKGROUND: The phagocytosis and homeostasis of microglia play an important role in promoting blood clearance and improving prognosis after subarachnoid hemorrhage (SAH). LC3-assocaited phagocytosis (LAP) contributes to the microglial phagocytosis and homeostasis via autophagy-related components. With RNA-seq sequencing, we found potential signal pathways and genes which were important for the LAP of microglia. METHODS: We used an in vitro model of oxyhemoglobin exposure as SAH model in the study. RNA-seq sequencing was performed to seek critical signal pathways and genes in regulating LAP. Bioparticles were used to access the phagocytic ability of microglia. Western blot (WB), immunoprecipitation, quantitative polymerase chain reaction (qPCR) and immunofluorescence were performed to detect the expression change of LAP-related components and investigate the potential mechanisms. RESULTS: In vitro SAH model, there were increased inflammation and decreased phagocytosis in microglia. At the same time, we found that the LAP of microglia was inhibited in all stages. RNA-seq sequencing revealed the importance of P38 MAPK signal pathway and DAPK1 in regulating microglial LAP. P38 was found to regulate the expression of DAPK1, and P38-DAPK1 axis was identified to regulate the LAP and homeostasis of microglia after SAH. Finally, we found that P38-DAPK1 axis regulated expression of BECN1, which indicated the potential mechanism of P38-DAPK1 axis regulating microglial LAP. CONCLUSION: P38-DAPK1 axis regulated the LAP of microglia via BECN1, affecting the phagocytosis and homeostasis of microglia in vitro SAH model. Video Abstract.

Diagnosis potential of subarachnoid hemorrhage using miRNA signatures isolated from plasma-derived extracellular vesicles.

The diagnosis and clinical management of aneurysmal subarachnoid hemorrhage (aSAH) is currently limited by the lack of accessible molecular biomarkers that reflect the pathophysiology of disease. We used microRNAs (miRNAs) as diagnostics to characterize plasma extracellular vesicles in aSAH. It is unclear whether they can diagnose and manage aSAH. Next-generation sequencing (NGS) was used to detect the miRNA profile of plasma extracellular vesicles (exosomes) in three patients with SAH and three healthy controls (HCs). We identified four differentially expressed miRNAs and validated the results using quantitative real-time polymerase chain reaction (RT-qPCR) with 113 aSAH patients, 40 HCs, 20 SAH model mice, and 20 sham mice. Exosomal miRNA NGS revealed that six circulating exosomal miRNAs were differentially expressed in patients with aSAH versus HCs and that the levels of four miRNAs (miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p) were differentially significant. After multivariate logistic regression analysis, only miR-369-3p, miR-486-3p, and miR-193b-3p enabled prediction of neurological outcomes. In a mouse model of SAH, greater expression of miR-193b-3p and miR-486-3p remained statistically significant relative to controls, whereas expression levels of miR-369-3p and miR-410-3p were lower. miRNA gene target prediction showed six genes associated with all four of these differentially expressed miRNAs. The circulating exosomes miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p may influence intercellular communication and have potential clinical utility as prognostic biomarkers for aSAH patients.

Efficacy and Safety of a Novel Plum Blossom Needling with Mild Moxibustion Device for Upper Limb Pain Disorder and Motor Dysfunction in Patients with Stage 1 Post-Stroke Shoulder-Hand Syndrome: Study Protocol for a Multi-Center, Single-Blind, Randomized Sham-Controlled Trial.

Background: Post-stroke shoulder-hand syndrome (PS-SHS), a common neurological comorbidity after stroke episodes, poses a grave threat on patients' functional recovery. Preliminary trials have demonstrated that the acupuncture and moxibustion treatment, including a dermal acupuncture tapping method known as plum blossom needling (PBN) can improve pain and motor dysfunctions in patients with PS-SHS. However, there are few reports describing simultaneous moxibustion treatment in combination with PBN. Hence, a novel plum blossom needle device with mild moxibustion (PBNMM) was developed to evaluate its potential efficacy and safety in patients with stage 1 PS-SHS. Materials and Methods: This multicenter, sham-controlled, randomized controlled trial (RCT) will recruit 102 eligible patients with stage 1 PS-SHS from three clinical centers, randomly allocated in a ratio of 1:1:1 to the PBNMM group, PBNMM with no moxa smoke (PBNMM-NMS) group and sham control group. Patients in each group will receive a 30-minute treatment once per day for 4 weeks, with 5 consecutive sessions per week, for a total of 20 sessions. The primary outcome measure will be defined as the decreased scores from baseline in the visual analog scale (VAS) assessment at week 4. Secondary outcome measures will include scores on the Fugl-Meyer Assessment of the Upper Extremity Scale (FMA-UE), the Modified Barthel Index (MBI), and the somatosensory evoked potential (SEP) records. All outcomes will be evaluated at baseline and weeks 4, 5, 6 and 10, and the intention-to-treat analysis will be applied. Conclusion: This study aims to provide robust evidence for the efficacy and safety of the PBNMM for PS-SHS treatment, as well as the specific impact of moxibustion smoke itself in dealing with PS-SHS. Clinical Trial Registration: Chinese Clinical Trial Registry No. ChiCTR2200062441. Registered on 7 August 2022.

Optimization of PROTAC Ternary Complex Using DNA Encoded Library Approach.

The proteolysis targeting chimera (PROTAC) strategy results in the down-regulation of unwanted protein(s) for disease treatment. In the PROTAC process, a heterobifunctional degrader forms a ternary complex with a target protein of interest (POI) and an E3 ligase, which results in ubiquitination and proteasomal degradation of the POI. While ternary complex formation is a key attribute of PROTAC degraders, modification of the PROTAC molecule to optimize ternary complex formation and protein degradation can be a labor-intensive and tedious process. In this study, we take advantage of DNA-encoded library (DEL) technology to efficiently synthesize a vast number of possible PROTAC molecules and describe a parallel screening approach that utilizes DNA barcodes as reporters of ternary complex formation and cooperative binding. We use a designed PROTAC DEL against BRD4 and CRBN to describe a dual protein affinity selection method and the direct discovery of novel, potent BRD4 PROTACs that importantly demonstrate clear SAR. Such an approach evaluates all the potential PROTACs simultaneously, avoids the interference of PROTAC solubility and permeability, and uses POI and E3 ligase proteins in an efficient manner.

Seasonal Variation of Hypolithic Microbiomes in the Gobi Desert : Seasonal Variation of Hypolithic Microbiomes in the Gobi Desert.

Understanding how microbial communities adapt to environmental stresses is critical for interpreting ecological patterns and microbial diversity. In the case of the Gobi Desert, little is known on the environmental factors that explain hypolithic colonization under quartz stones. By analyzing nine hypolithic communities across an arid gradient and the effects of the season of the year in the Hexi Corridor of this desert, we found a significant decrease in hypolithic colonization rates (from 47.24 to 15.73%) with the increasing drought gradient and found two distinct communities in Hot and Cold samples, which survived or proliferated after a hot or a cold period. While Cold communities showed a greater species diversity and a predominance of Cyanobacteria, Hot communities showed a predominance of members of the Proteobacteria and the Firmicutes. In comparison, Cold communities also possessed stronger functions in the photosynthesis and carbon metabolism. Based on the findings of this study, we proposed that the hypolithic communities of the Hexi Corridor of the Gobi Desert might follow a seasonal developmental cycle in which temperature play an important role. Thus after a critical thermal threshold is crossed, heterotrophic microorganisms predominate in the hot period, while Cyanobacteria predominate in the cold period.

Long-Term Elevated Siglec-10 in Cerebral Spinal Fluid Heralds Better Prognosis for Patients with Aneurysmal Subarachnoid Hemorrhage.

The presence of aneurysmal subarachnoid hemorrhage (aSAH) is usually accompanied by excessive inflammatory response leading to damage of the central nervous system, and the sialic acid-binding Ig-like lectin 10 (Siglec-10) is a recognized factor being able to modify the inflammatory reaction. To investigate the potential role of Siglec-10 in aSAH, we collected the cerebrospinal fluid (CSF) of control (n = 11) and aSAH (n = 14) patients at separate times and measured the Siglec-10 concentration utilizing the enzyme-linked immunosorbent assay (ELISA) and evaluated the alterations of GOS and GCS during the disease process. In accordance with the STROBE statement, results showed that Siglec-10 in CSF rose quickly in response aSAH attack and then fell back to a slightly higher range above baseline, while it remained at relative high concentration and last longer in several severely injured patients. In general, higher Siglec-10 expression over a longer period usually indicated a better clinical prognosis. This prospective cohort study suggested that Siglec-10 could possibly be used as a biomarker for predicting prognosis of aSAH due to its ability to balance aSAH-induced nonsterile inflammation. Additionally, these findings might provide novel therapeutic perspectives for aSAH and other inflammation-related diseases.

Continued P2X7 activation leads to mitochondrial fission and compromising microglial phagocytosis after subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH) has a high rate of disability and mortality. Extremely damaging molecules, including adenosine triphosphate (ATP), are released from extravasated red blood cells and nerve cells, which activate microglia and induce sterile tissue injury and organ dysfunction. P2X purinoceptor 7 (P2X7) is one of the most important purine receptors on the microglial surface and is involved in the proinflammatory activation of microglia. While P2X7 can also affect microglial phagocytosis, the mechanism is not clear. Here, we demonstrated that microglial phagocytosis is progressively impaired under continued BzATP exposure and P2X7 activation. Furthermore, we found that P2X7 activation leads to increased intracellular Ca2+ levels and activates Calcineurin, which dephosphorylates dynamin-related protein 1 (DRP1) S637. The dephosphorylation of DRP1 at S637 leads to increased mitochondrial fission and decreased mitochondrial function, which may be responsible for the decreased microglial phagocytosis. Finally, we pharmacologically inhibited P2X7 activation in mice, which resulted in rescue of mitochondrial function and decreased microglial proliferation, but improved phagocytosis after SAH. Our study confirmed that P2X7 activation after SAH leads to the impairment of microglial phagocytosis through mitochondrial fission and verified that P2X7 inhibition restores microglial phagocytosis both in vitro and in vivo.

Astrocytic CD24 Protects Neuron from Recombinant High-Mobility Group Box 1 Protein(rHMGB1)-Elicited Neuronal Injury.

Endogenous host-derived molecules named damage-associated molecular patterns (DAMPs) can induce excessive non-sterile inflammatory responses on recognition of specific membrane-tethered receptors. Here in this study, we aimed to explore the role of DAMP molecule HMGB1 in astrocyte-mediated sterile neuroinflammation and the resultant influences on neurons. In vitro cultured astrocytes were challenged with rHMGB1 and then harvested at 6 h, 12 h, 24 h, 36 h, and 48 h, respectively. The astrocytic CD24 expression was determined by quantitative real-time polymerase chain reaction (qPCR), Western blot analysis and immunofluorescence, nuclear factor kappa B (NF-κB) binding activity was detected by electrophoretic mobility shift assay (EMSA), and the proinflammatory factors, tumor necrosis factor-α (TNF-α), and interleukin 1ß (IL-1ß), were measured by qPCR. The neuronal morphology was assessed with phase-contrast microscopy. The results showed that astrocytic mRNA and protein CD24 expression began to rise at 24 h, peaked at 36 h, and remained elevated at 48 h after rHMGB1 stimulation, accompanied with enhanced NF-κB binding activity and augmented expression of TNF-α and IL-1ß. Furthermore, rHMGB1 caused cocultured neuron damage and was aggregated upon CD24 knockdown. Taken together, these novel findings suggested that rHMGB1 could promote astrocytic CD24 expression, the inhibition of which could aggregate neuronal damage.

High Expression of PDK4 Could Play a Potentially Protective Role by Attenuating Oxidative Stress after Subarachnoid Hemorrhage.

Pyruvate dehydrogenase (PDH), a key enzyme on the mitochondrial outer membrane, has been found to decrease activity notably in early brain injury (EBI) after subarachnoid hemorrhage (SAH). It has been demonstrated that PDH is associated with the production of reactive oxygen species (ROS) and apoptosis. Hence, in this study, we aimed to determine the cause of the decreased PDH activity and explore the potential role of PDH in EBI. We investigated the expression changes of PDH and pyruvate dehydrogenase kinase (PDK) in vivo and in vitro. Then, we explored the possible effects of PDH and ROS after SAH. The results showed that early overexpression of PDK4 promoted the phosphorylation of PDH, inhibited PDH activity, and may play a protective role after SAH in vivo and in vitro. Finally, we investigated the levels of PDK4 and pyruvate, which accumulated due to decreased PDH activity, in the cerebrospinal fluid (CSF) of 34 patients with SAH. Statistical analysis revealed that PDK4 and pyruvate expression was elevated in the CSF of SAH patients compared with that of controls, and this high expression correlated with the degree of neurological impairment and long-term outcome. Taken together, the results show that PDK4 has the potential to serve as a new therapeutic target and biomarker for assisting in the diagnosis of SAH severity and prediction of recovery.

Catalyst-free synthesis of sub-5 nm silicon nanowire arrays with massive lattice contraction and wide bandgap.

The need for miniaturized and high-performance devices has attracted enormous attention to the development of quantum silicon nanowires. However, the preparation of abundant quantities of silicon nanowires with the effective quantum-confined dimension remains challenging. Here, we prepare highly dense and vertically aligned sub-5 nm silicon nanowires with length/diameter aspect ratios greater than 10,000 by developing a catalyst-free chemical vapor etching process. We observe an unusual lattice reduction of up to 20% within ultra-narrow silicon nanowires and good oxidation stability in air compared to conventional silicon. Moreover, the material exhibits a direct optical bandgap of 4.16 eV and quasi-particle bandgap of 4.75 eV with the large exciton binding energy of 0.59 eV, indicating the significant phonon and electronic confinement. The results may provide an opportunity to investigate the chemistry and physics of highly confined silicon quantum nanostructures and may explore their potential uses in nanoelectronics, optoelectronics, and energy systems.

Palladium-Mediated Hydroamination of DNA-Conjugated Aryl Alkenes.

C-N bond formation is one of the most commonly used reactions in medicinal chemistry. Herein, we report an efficient Pd-promoted hydroamination reaction between DNA-conjugated aryl alkenes and a wide scope of aliphatic amines. The described reactions are demonstrated in good to excellent conversions to furnish C (sp3)-N bonds on DNA. This DNA-compatible transformation has strong potentials for the application into DNA-encoded library synthesis.

Efficacy of Moxibustion Smoke for Stage 1 Post-Stroke Shoulder-Hand Syndrome: Protocol for a Multi-Center, Single-Blind Randomized Sham-Controlled Trial.

Objective: This study aims to evaluate the safety and efficacy of various levels of moxibustion smoke concentration (MSC), represented by particulate matter 10mm (PM10), on pain and motor dysfunction in patients with stage 1 post-stroke shoulder-hand syndrome (SHS). Materials and Methods: In this multi-center, sham-controlled, single-blind, randomized controlled trial (RCT), a total of 140 eligible patients with stage 1 post-stroke SHS will be recruited from March 2022 to February 2023 and randomly allocated to five groups in a ratio of 1:1:1:1:1. Moxibustion, in addition to standard medical care, will be applied to subjects in all groups. No acupoints on the affected upper limb will be utilized. Moxibustion smoke therapy, with varying levels of MSC, will be applied to the five groups as follows: (A) sham control group, (B) zero MSC group, (C) low MSC group, (D) medium MSC group, and (E) high MSC group. Patients in each group will be treated for 20 minutes per session, with five sessions each week, over a course of six weeks, with a total follow-up interval of eight weeks. The primary outcome measure will be a visual analog scale (VAS) assessment of the intensity of regionalized pain in the affected upper limb. Secondary outcome measures will include scoring on the Fugl-Meyer Assessment of the Upper Extremity Scale (FMA-UE), the Modified Barthel Index (MBI) and the measurement of somatosensory evoked potential (SEP). All participants will be evaluated before treatment, during treatment (ie, at two weeks and four weeks), immediately after concluding treatment (ie, at six weeks) and at two weeks post-treatment (ie, at eight weeks). Intention-to-treat analysis will be applied. Trial Registration Number: ChiCTR2100043076.

[WANG Ju-yi's meridian diagnosis method combined with Bobath rehabilitation training for post-stroke shoulder-hand syndrome typeâ ].

OBJECTIVE: To compare the clinical efficacy differences between WANG Ju-yi 's meridian diagnosis method combined with Bobath rehabilitation training and Bobath rehabilitation training alone for post-stroke shoulder-hand syndrome (SHS) typeⅠ. METHODS: A total of 106 patients with post-stroke SHS typeⅠwere randomly divided into an observation group (53 cases, 2 cases dropped off ) and a control group (53 cases, 3 cases dropped off ). The patients in the both groups were treated with medications for basic diseases and conventional acupuncture at Waiguan (TE 5), Shousanli (LI 10) and Jianyu (LI 15) on the affected side. In addition, the patients in the control group were treated with Bobath rehabilitation training, 20 minutes each time; on the basis of the control group, the patients in the observation group were treated with WANG Ju-yi's meridian diagnosis method to adjust the abnormal parts in meridians of the hand taiyin and hand yangming on the affected side, 20 minutes each time. Both groups were treated once a day, 5 times a week for 8 weeks. The scores of visual analogue scale (VAS), upper-limb Fugl-Meyer assessment (FMA) and Barthel index (BI) were recorded before and after treatment as well as 6 weeks after treatment (follow-up), and the clinical efficacy of the two groups was evaluated after treatment. RESULTS: Compared before treatment, the VAS scores were reduced and the scores of upper-limb FMA and BI were increased in the two groups after treatment and in the follow-up (P<0.05). The VAS score in the observation group was lower than that in the control group (P<0.05), and the scores of upper-limb FMA and BI in the observation group were higher than those of the control group (P<0.05). The total effective rate in the observation group was 82.4% (42/51), which was higher than 62.0% (31/50) in the control group (P<0.05). CONCLUSION: WANG Ju-yi 's meridian diagnosis method combined with Bobath rehabilitation training could effectively treat post-stroke SHS typeⅠ, reduce pain symptoms and improve joint motor dysfunction, and improve the quality of life. Its curative effect is better than Bobath rehabilitation training alone.

Knock-Down of CD24 in Astrocytes Aggravates Oxyhemoglobin-Induced Hippocampal Neuron Impairment.

Subarachnoid hemorrhage (SAH), as one of the most severe hemorrhagic strokes, is closely related to neuronal damage. Neurogenesis is a promising therapy, however, reliable targets are currently lacking. Increasing evidence has indicated that CD24 is associated with the growth of hippocampal neurons and the regulation of neural stem/precursor cell proliferation. To investigate the potential effect of CD24 in astrocytes on neuron growth in the hippocampus, we used a Transwell co-culture system of hippocampal astrocytes and neurons, and oxyhemoglobin (OxyHb) was added to the culture medium to mimic SAH in vitro. A specific lentivirus was used to knock down CD24 expression in astrocytes, which was verified by western blot, quantitative real-time polymerase chain reaction, and immunofluorescent staining. Astrocyte activation, neurite elongation, neuronal apoptosis, and cell viability were also assessed. We first determined the augmented expression level of CD24 in hippocampal astrocytes after SAH. A similar result was observed in cultured astrocytes exposed to OxyHb, and a corresponding change in SHP2/ERK was also noticed. CD24 in astrocytes was then downregulated by the lentivirus, which led to the impairment of axons and dendrites on the co-cultured neurons. Aggravated neuronal apoptosis was induced by the CD24 downregulation in astrocytes, which might be a result of a lower level of brain derived neurotrophic factor (BDNF). In conclusion, the knock-down of CD24 in astrocytes suppressed hippocampal neuron growth, in which the SHP2-ERK signaling pathway and BNDF were possibly involved.

Somatic mosaicism in the MAPK pathway in sporadic brain arteriovenous malformation and association with phenotype.

OBJECTIVE: Sporadic brain arteriovenous malformation (BAVM) is a tangled vascular lesion characterized by direct artery-to-vein connections that can cause life-threatening intracerebral hemorrhage (ICH). Recently, somatic mutations in KRAS have been reported in sporadic BAVM, and mutations in other mitogen-activated protein kinase (MAPK) signaling pathway genes have been identified in other vascular malformations. The objectives of this study were to systematically evaluate somatic mutations in MAPK pathway genes in patients with sporadic BAVM lesions and to evaluate the association of somatic mutations with phenotypes of sporadic BAVM severity. METHODS: The authors performed whole-exome sequencing on paired lesion and blood DNA samples from 14 patients with sporadic BAVM, and 295 genes in the MAPK signaling pathway were evaluated to identify genes with somatic mutations in multiple patients with BAVM. Digital droplet polymerase chain reaction was used to validate KRAS G12V and G12D mutations and to assay an additional 56 BAVM samples. RESULTS: The authors identified a total of 24 candidate BAVM-associated somatic variants in 11 MAPK pathway genes. The previously identified KRAS G12V and G12D mutations were the only recurrent mutations. Overall, somatic KRAS G12V was present in 14.5% of BAVM lesions and G12D was present in 31.9%. The authors did not detect a significant association between the presence or allelic burden of KRAS mutation and three BAVM phenotypes: lesion size (maximum diameter), age at diagnosis, and age at ICH. CONCLUSIONS: The authors confirmed the high prevalence of somatic KRAS mutations in sporadic BAVM lesions and identified several candidate somatic variants in other MAPK pathway genes. These somatic variants may contribute to understanding of the etiology of sporadic BAVM and the clinical characteristics of patients with this condition.

PDK4 Decrease Neuronal Apoptosis via Inhibiting ROS-ASK1/P38 Pathway in Early Brain Injury After Subarachnoid Hemorrhage.

Aims: Metabolic disorders may play key roles in oxidative stress and neuronal apoptosis in response to early brain injury (EBI) after subarachnoid hemorrhage (SAH). Pyruvate dehydrogenase (PDH) is related to oxidative stress in EBI, and its activity obviously decreases after SAH. We discovered that only pyruvate dehydrogenase kinase 4 (PDK4) expression was obviously increased among the four PDK isozymes after SAH in preliminary experiments. Therefore, we attempted to investigate the effects and corresponding mechanisms of PDK4 on oxidative stress after SAH. Results: First, we confirmed that PDK4 overexpression promoted PDH phosphorylation, inhibited PDH activity, and changed cell metabolism after SAH. A small interfering RNA (siRNA) targeting PDK4, a lentiviral PDK4 overexpression vector, and dichloroacetic acid (DCA) were used to regulate the expression and activity of PDK4. The siRNA decreased PDH phosphorylation, promoted reactive oxygen species (ROS) production, activated the apoptosis signal-regulating kinase 1 (ASK1)/P38 pathway, and induced neuronal apoptosis. The lentivirus further attenuated PDH activity, oxidative stress, and neuronal apoptosis. DCA inhibited the activity of PDK4, but increased the expression of PDK4 due to a feedback mechanism. Inactivated PDK4 did not effectively suppress PDH activity, which increased ROS production, activated the ASK1/P38 pathway, and led to neuronal apoptosis. Innovation: This study provides new insights into the potential antioxidant and antiapoptotic effects of the PDK4-PDH axis on EBI after SAH. Conclusions: The early overexpression of PDK4 after SAH may attenuate neuronal apoptosis by reducing oxidative stress via the ROS/ASK1/P38 pathway. PDK4 may be a new potential therapeutic target to ameliorate EBI after SAH. Antioxid. Redox Signal. 36, 505-524.