Mechanistic insight into lysyl oxidase in vascular remodeling and angiogenesis.

Vascular remodeling and angiogenesis are two key processes in the maintenance of vascular homeostasis and involved in a wide array of vascular pathologies. Following these processes, extracellular matrix (ECM) provides the mechanical foundation for vascular walls. Lysyl oxidase (LOX), the key matrix-modifying enzyme, has been demonstrated to significantly affect structural abnormality and dysfunction in the blood vessels. The role of LOX in vascular remodeling and angiogenesis has always been the subject in the current medical research. Therefore, we presently make a summarization of the biosynthesis of LOX and the mechanisms involved in vascular remodeling and angiogenesis, as well as the role of LOX in diseases associated with vascular abnormalities and the therapeutic potential via targeting LOX. In particular, we give a proposal that LOX likely reshapes matrisome-associated genes expressions in the regulation of vascular remodeling and angiogenesis, which serves as a mechanistic insight into the critical role of LOX in these two aspects. Additionally, LOX has also dual effects on the vascular dysfunction, namely, inhibition of LOX for improving hypertension, restenosis and malignant tumor while activation of LOX for curing arterial aneurysm and dissection. LOX-targeted therapy may provide a promising therapeutic strategy for the treatment of various vascular pathologies associated with vascular remodeling and angiogenesis.

Identification and validation of roles of lysyl oxidases in the predictions of prognosis, chemotherapy and immunotherapy in glioma.

Background: Previous investigations have illustrated that lysyl oxidase family enzymes (LOXs) are contributing factors for tumor progression and remodeling immunomicroenvironment. However, it is scarce regarding comprehensive analysis of LOXs in the predictions of prognosis, chemotherapy and immunotherapy in glioma, the highly invasive brain tumor. Our present work aimed to explore the prognostic value, chemotherapeutic drug sensitivity and immunotherapy according to distinct LOXs expressions in glioma through bioinformatics analysis and experimental verification. Methods: We collected gene expression data and clinical characteristics from the public databases including Chinese Glioma Genome Atlas (CGGA)-325, CGGA-693, the Cancer Genome Atlas (TCGA), IMvigor210 and Van Allen 2015 cohorts. The correlations between the clinicopathological factors and differential LOXs expressions were analyzed. The ROC curve and Kaplan-Meier analysis were conducted to evaluate the prediction ability of prognosis. Chemotherapeutic drug sensitivity via distinct LOXs expression levels was predicted using the pRRophetic package. Immune score, immune cell infiltration and immune checkpoint expression levels were also analyzed through diverse algorithms in R software. Finally, mRNA and protein expressions of LOXs were validated in glioma cells (T98G and A172) by real-time quantitative PCR and Western blot, respectively. Results: Our results demonstrated that high levels of LOXs expressions were positively associated with glioma grades, older age and MGMT unmethylated status while elevations of LOXs were negatively correlated with IDH mutation or 1p/19q co-deletion. Furthermore, the glioma patients with low levels of LOXs also exhibited better prognosis. Also, differential LOXs expressions were associated with at least 12 chemotherapeutic drug sensitivity. Besides, it was also found that glioma patients with high LOXs expressions showed higher enrichment scores for immune cell infiltration and increased levels of immune checkpoints, suggesting the critical role of distinct LOXs expression levels for glioma immunotherapy. The predictive roles of LOXs expression in tumor immunotherapy were also validated in two immunotherapy cohorts including IMvigor 210 and Van Allen 2015. Experimental results revealed that expressions of LOX, LOXL1, LOXL2, and LOXL3 were higher in glioma cell lines at mRNA and protein levels. Conclusion: Our findings altogether indicate that LOXs have potent predictive value for prognosis, chemotherapy and immunotherapy in glioma patients.

D-Penicillamine Reveals the Amelioration of Seizure-Induced Neuronal Injury via Inhibiting Aqp11-Dependent Ferroptosis.

Repetitive seizures, a common phenomenon in diverse neurologic conditions such as epilepsy, can undoubtedly cause neuronal injury and our prior work reveals that ferroptosis is a contributing factor of neuronal damage post seizure. However, there is no drug available in clinical practice for ameliorating seizure-induced neuronal impairment via targeting ferroptosis. Our present work aimed to explore whether D-penicillamine (DPA), an originally approved drug for treating Wilson's disease, inhibited neuronal ferroptosis and alleviated seizure-associated brain damage. Our findings revealed that DPA remarkably improved neuronal survival in kainic acid (KA)-treated mouse model. Furthermore, ferroptosis-associated indices including acyl-coA synthetase long chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (Ptgs2) gene and lipid peroxide (LPO) level were significantly decreased in KA mouse model after DPA treatment. In a ferroptotic cell death model induced by glutamate or erastin, DPA was also validated to evidently suppress neuronal ferroptosis. The results from RNA-seq analysis indicated that Aqp11, a gene coding previously reported channel protein responsible for transporting water and small solutes, was identified as a molecular target by which DPA exerted anti-ferroptotic potential in neurons. The experimental results from in vivo Aqp11 siRNA transfer into the brain also confirmed that knockdown of Aqp11 abrogated the inhibitory effect of seizure-induced ferroptosis after DPA treatment, suggesting that the effects of DPA on ferroptosis process are dependent upon Aqp11. In conclusion, DPA can be repurposed to cure seizure disorders such as epilepsy.

Ferrostatin-1 obviates seizures and associated cognitive deficits in ferric chloride-induced posttraumatic epilepsy via suppressing ferroptosis.

Posttraumatic epilepsy (PTE) is a prevalent complication of brain trauma. Current anti-epileptic drugs available do not have satisfactory response to PTE. It is of desperate need to explore novel therapeutic approaches for curing PTE. Our prior work revealed that ferroptosis, a recently discovered mode of cell death, occurs in rodent model of PTE. In the present study, we aimed to further investigate the effect of ferrostatin-1 (Fer-1), a specific ferroptosis inhibitor, on seizure behavior and cognitive deficit in a mouse model of PTE. The preparation of PTE was performed by stereotaxical injection in the somatosensory cortex region of 50 mM FeCl3. Seizure activity was assessed via Racine scoring and electroencephalogram analysis. PTE-related cognitive function was evaluated by novel object recognition and Morris water maze tests. Ferroptosis-related indices including glutathione peroxidase (GPx) activity and protein expressions of 4-hydroxynonenal (4-HNE) were detected using a commercial kit and immunofluorescence, respectively. It was found that treatment with Fer-1 significantly exerted protective effects against acute seizure and memory decline, although no evident effect on epileptic progression. Fer-1 also exhibited good tolerability and safety as we observed that it hardly influenced the body weight. Furthermore, it was noted that administration of Fer-1 suppressed ferroptosis-related indices including GPx activity and protein expressions of 4-HNE in hippocampus. These data altogether indicate that Fer-1 has potent therapeutic effects against seizures and cognitive impairment following PTE-induced brain insult. Fer-1 may act as a promising drug for curing PTE patients.

The mutual interplay of redox signaling and connexins.

Connexins (Cxs) are ubiquitous transmembrane proteins that possess both channel function (e.g., formations of gap junction and hemichannel) and non-channel properties (e.g., gene transcription and protein-protein interaction). Several factors have been identified to play a role in the regulation of Cxs, which include those acting intracellularly, as redox potential, pH, intramolecular interactions, and post-translational modifications (e.g., phosphorylation, S-nitrosylation) as well as those acting extracellularly, such as Ca2+ and Mg2+. The relationship between redox signaling and Cxs attracts considerable attention in recent years. There is ample evidence showing that redox signaling molecules (e.g., hydrogen peroxide (H2O2), nitric oxide (NO)) affect Cxs-based channel function while the opening of Cx channels also triggers the transfer of various redox-related metabolites (e.g., reactive oxygen species, glutathione, nicotinamide adenine dinucleotide, and NO). On the basis of these evidences, we propose the existence of redox-Cxs crosstalk. In this review, we briefly discuss the interaction between redox signaling and Cxs and the implications of the intersection in disease pathology and future therapeutic interventions.

Dietary nutrition for neurological disease therapy: Current status and future directions.

Adequate food intake and relative abundance of dietary nutrients have undisputed effects on the brain function. There is now substantial evidence that dietary nutrition aids in the prevention and remediation of neurologic symptoms in diverse pathological conditions. The newly described influences of dietary factors on the alterations of mitochondrial dysfunction, epigenetic modification and neuroinflammation are important mechanisms that are responsible for the action of nutrients on the brain health. In this review, we discuss the state of evidence supporting that distinct dietary interventions including dietary supplement and dietary restriction have the ability to tackle neurological disorders using Alzheimer's disease, Parkinson's disease, stroke, epilepsy, traumatic brain injury, amyotrophic lateral sclerosis, Huntington's disease and multiple sclerosis as examples. Additionally, it is also highlighting that diverse potential mechanisms such as metabolic control, epigenetic modification, neuroinflammation and gut-brain axis are of utmost importance for nutrient supply to the risk of neurologic condition and therapeutic response. Finally, we also highlight the novel concept that dietary nutrient intervention reshapes metabolism-epigenetics-immunity cycle to remediate brain dysfunction. Targeting metabolism-epigenetics-immunity network will delineate a new blueprint for combating neurological weaknesses.

Corrigendum: Neuroprotective Effects of the Anti-Cancer Drug Lapatinib Against Epileptic Seizures via Suppressing Glutathione Peroxidase 4-Dependent Ferroptosis.

[This corrects the article DOI: 10.3389/fphar.2020.601572.].

Neuroprotective Effects of the Anti-cancer Drug Lapatinib Against Epileptic Seizures via Suppressing Glutathione Peroxidase 4-Dependent Ferroptosis.

Epilepsy is a complex neurological disorder characterized by recurrent and unprovoked seizures. Neuronal death process is implicated in the development of repetitive epileptic seizures. Therefore, cell death can be harnessed for ceasing seizures and epileptogenesis. Oxidative stress is regarded as a contributing factor of neuronal death activation and there is compelling evidence supporting antioxidants hold promise in abrogating seizure-related cell modality. Lapatinib, a well-known anti-cancer drug, has been traditionally reported to exert anti-tumor effect via modulating oxidative stress and a recent work illustrates the improvement of encephalomyelitis in rodent models after lapatinib treatment. However, whether lapatinib is beneficial for inhibiting neuronal death and epileptic seizure remains unknown. Here, we found that lapatinib remarkably prevented kainic acid (KA)-epileptic seizures in mice and ferroptosis, a newly defined cell death which is associated with oxidative stress, was involved in the neuroprotection of lapatinib. In the ferroptotic cell death model, lapatinib exerted neuroprotection via restoring glutathione peroxidase 4 (GPX4). Treatment with GPX4 inhibitor ras-selective lethal small molecule 3 (RSL3) abrogated its anti-ferroptotic potential. In a mouse model of KA-triggered seizure, it was also validated that lapatinib blocked GPX4-dependent ferroptosis. It is concluded that lapatinib has neuroprotective potential against epileptic seizures via suppressing GPX4-mediated ferroptosis.

Antioxidants Targeting Mitochondrial Oxidative Stress: Promising Neuroprotectants for Epilepsy.

Mitochondria are major sources of reactive oxygen species (ROS) within the cell and are especially vulnerable to oxidative stress. Oxidative damage to mitochondria results in disrupted mitochondrial function and cell death signaling, finally triggering diverse pathologies such as epilepsy, a common neurological disease characterized with aberrant electrical brain activity. Antioxidants are considered as promising neuroprotective strategies for epileptic condition via combating the deleterious effects of excessive ROS production in mitochondria. In this review, we provide a brief discussion of the role of mitochondrial oxidative stress in the pathophysiology of epilepsy and evidences that support neuroprotective roles of antioxidants targeting mitochondrial oxidative stress including mitochondria-targeted antioxidants, polyphenols, vitamins, thiols, and nuclear factor E2-related factor 2 (Nrf2) activators in epilepsy. We point out these antioxidative compounds as effectively protective approaches for improving prognosis. In addition, we specially propose that these antioxidants exert neuroprotection against epileptic impairment possibly by modulating cell death interactions, notably autophagy-apoptosis, and autophagy-ferroptosis crosstalk.