Parkin-Dependent Mitophagy is Required for the Inhibition of ATF4 on NLRP3 Inflammasome Activation in Cerebral Ischemia-Reperfusion Injury in Rats

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Neuroprotective potential for mitigating ischemia-reperfusion-induced damage

Reperfusion following cerebral ischemia causes both structural and functional damage to brain tissue and could aggravate a patient's condition; this phenomenon is known as cerebral ischemia-reperfusion injury. Current studies have elucidated the neuroprotective role of the sirtuin protein family (Sirtuins) in modulating cerebral ischemia-reperfusion injury. However, the potential of utilizing it as a novel intervention target to influence the prognosis of cerebral ischemia-reperfusion injury requires additional exploration. In this review, the origin and research progress of Sirtuins are summarized, suggesting the involvement of Sirtuins in diverse mechanisms that affect cerebral ischemia-reperfusion injury, including inflammation, oxidative stress, blood-brain barrier damage, apoptosis, pyroptosis, and autophagy. The therapeutic avenues related to Sirtuins that may improve the prognosis of cerebral ischemia-reperfusion injury were also investigated by modulating Sirtuins expression and affecting representative pathways, such as nuclear factor-kappa B signaling, oxidative stress mediated by adenosine monophosphate-activated protein kinase, and the forkhead box O. This review also summarizes the potential of endogenous substances, such as RNA and hormones, drugs, dietary supplements, and emerging therapies that regulate Sirtuins expression. This review also reveals that regulating Sirtuins mitigates cerebral ischemia-reperfusion injury when combined with other risk factors. While Sirtuins show promise as a potential target for the treatment of cerebral ischemia-reperfusion injury, most recent studies are based on rodent models with circadian rhythms that are distinct from those of humans, potentially influencing the efficacy of Sirtuins-targeting drug therapies. Overall, this review provides new insights into the role of Sirtuins in the pathology and treatment of cerebral ischemia-reperfusion injury.

Decoding ischemic stroke: Perspectives on the endoplasmic reticulum, mitochondria, and their crosstalk

Stroke is known for its high disability and mortality rates. Ischemic stroke (IS), the most prevalent form, imposes a considerable burden on affected individuals. Nevertheless, existing treatment modalities are hindered by limitations, including narrow therapeutic windows, substantial adverse effects, and suboptimal neurological recovery. Clarifying the pathological mechanism of IS is a prerequisite for developing new therapeutic strategies. In this context, the functional disruption of mitochondria, the endoplasmic reticulum (ER), and the crosstalk mechanisms between them have garnered increasing attention for their contributory roles in the progression of IS. Therefore, this review provides a comprehensive summary of the current pathomechanisms associated with the involvement of the ER and mitochondria in IS, emphasising Ca2+ destabilization homeostasis, ER stress, oxidative stress, disordered mitochondrial quality control, and mitochondrial transfer. Additionally, this article highlights the functional interaction between the ER and mitochondria, as well as the mitochondrial-ER contacts (MERCs) that structurally connect mitochondria and the ER, aiming to provide ideas and references for the research and treatment of IS.

Mechanisms Associated with Mitophagy and Ferroptosis in Cerebral Ischemia-reperfusion Injury

Ischemic stroke (IS) constitutes a major threat to human health. Vascular recanalization by intravenous thrombolysis and mechanical thrombolysis remain the most significant and effective methods for relief of ischemia. Key elements of these treatments include achieving blood-vessel recanalization, restoring brain-tissue reperfusion, and preserving the ischemic penumbra. However, in achieving the therapeutic goals of vascular recanalization, secondary damage to brain tissue from cerebral ischemia-reperfusion injury (CIRI) must also be addressed. Despite advancements in understanding the pathological processes associated with CIRI, effective interventions to prevent its onset and progression are still lacking. Recent research has indicated that mitophagy and ferroptosis are critical mechanisms in the development of CIRI, and significantly contribute to the onset and progression of IS and CIRI because of common targets and co-occurrence mechanisms. Therefore, exploring and summarizing the potential connections between mitophagy and ferroptosis during CIRI is crucial. In the present review, we mainly focused on the mechanisms of mitochondrial autophagy and ferroptosis, and their interaction, in the development of CIRI. We believe that the data show a strong relationship between mitochondrial autophagy and ferroptosis with interactive regulation. This information may underpin new potential approaches for the prevention and treatment of IS and subsequent CIRI.

Organellar quality control crosstalk in aging-related disease: Innovation to pave the way

Organellar homeostasis and crosstalks within a cell have emerged as essential regulatory and determining factors for the survival and functions of cells. In response to various stimuli, cells can activate the organellar quality control systems (QCS) to maintain homeostasis. Numerous studies have demonstrated that dysfunction of QCS can lead to various aging-related diseases such as neurodegenerative, pulmonary, cardiometabolic diseases and cancers. However, the interplay between QCS and their potential role in these diseases are poorly understood. In this review, we present an overview of the current findings of QCS and their crosstalk, encompassing mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes, peroxisomes, lipid droplets, and lysosomes as well as the aberrant interplays among these organelles that contributes to the onset and progression of aging-related disorders. Furthermore, potential therapeutic approaches based on these quality control interactions are discussed. Our perspectives can enhance insights into the regulatory networks underlying QCS and the pathology of aging and aging-related diseases, which may pave the way for the development of novel therapeutic targets.

Pulsed electromagnetic fields inhibit IL-37 to alleviate CD8+ T cell dysfunction and suppress cervical cancer progression

Pulsed electromagnetic field (PEMF) therapy is a potential non-invasive treatment to modulate immune responses and inhibit tumor growth. Cervical cancer (CC) is influenced by IL-37-mediated immune regulation, making PEMF therapy a potential strategy to impede CC progression. This study aimed to elucidate the effects of PEMF on IL-37 regulation and its molecular mechanisms in CC. CC cell-xenografted mouse models, including IL-37 transgenic (IL-37tg) mice, were used to assess tumor growth through in vivo fluorescence imaging and analyze CC cell apoptosis via flow cytometry. TCGA-CESC transcriptome and clinical data were analyzed to identify key inflammation and immune-related genes. CD8+ T cell models were stimulated with PEMF, and apoptosis, oxidative stress, and inflammatory factor expression were analyzed through RT-qPCR, Western blot, and flow cytometry. PEMF treatment significantly inhibited IL-37 expression (p < 0.05), promoted inflammatory factor release (TNF-α and IL-6), and activated oxidative stress, leading to increased CC cell apoptosis (p < 0.05). IL-37 interaction with SMAD3 impacted the p38/NF-κB signaling pathway, modulating CD8+ T cell activity and cytotoxicity. Co-culture of Hela cells with CD8+ T cells under PEMF treatment showed reduced proliferation (by 40%), migration, and invasion (p < 0.05). In vivo experiments with CC-bearing mice demonstrated that PEMF treatment downregulated IL-37 expression (p < 0.05), enhanced CD8+ T cell function, and inhibited tumor growth (p < 0.05). These molecular mechanisms were validated through RT-qPCR, Western blot, and immunohistochemistry. Thus, PEMF therapy inhibits CC progression by downregulating IL-37 and improving CD8+ T cell function via the SMAD3/p38/NF-κB signaling pathway.

AdipoRon exerts an antidepressant effect by inhibiting NLRP3 inflammasome activation in microglia via promoting mitophagy

Depression is a serious mental disorder that threatens patients' physical and mental health worldwide. The activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome is essential for microglia-mediated neuroinflammation and neuronal damage in depression. Numerous pathophysiological factors, such as mitochondrial dysfunction and impaired mitophagy, have an essential role in activating the NLRP3 inflammasome. AdipoRon is a potent adiponectin receptor agonist; however, its antidepressant effects have not been thoroughly investigated. In this study, we found that AdipoRon ameliorated depression-like behavior and neuronal damage induced by chronic unpredictable mild stress (CUMS). Further research demonstrated that AdipoRon inhibited the activation of the NLRP3 inflammasome and protected hippocampal neurons from microglial cytotoxicity by promoting mitophagy, increasing the clearance of damaged mitochondria, and reducing mtROS accumulation. Importantly, inhibition of mitophagy attenuated the antidepressant and neuroprotective effects of AdipoRon. Overall, these findings indicate that AdipoRon alleviates depression by inhibiting NLRP3 inflammasome activation in microglia via improving mitophagy.

Fighting ischemia-reperfusion injury: Focusing on mitochondria-derived ferroptosis

Ischemia-reperfusion injury (IRI) is a major cause of mortality and morbidity. Current treatments for IRI have limited efficacy and novel therapeutic strategies are needed. Mitochondrial dysfunction not only initiates IRI but also plays a significant role in ferroptosis pathogenesis. Recent studies have highlighted that targeting mitochondrial pathways is a promising therapeutic approach for ferroptosis-induced IRI. The association between ferroptosis and IRI has been reviewed many times, but our review provides the first comprehensive overview with a focus on recent mitochondrial research. First, we present the role of mitochondria in ferroptosis. Then, we summarize the evidence on mitochondrial manipulation of ferroptosis in IRI and review recent therapeutic strategies aimed at targeting mitochondria-related ferroptosis to mitigate IRI. We hope our review will provide new ideas for the treatment of IRI and accelerate the transition from bench to bedside.

Deciphering the neuroprotective mechanisms of RACK1 in cerebral ischemia-reperfusion injury: Pioneering insights into mitochondrial autophagy and the PINK1/Parkin axis

INTRODUCTION

Cerebral ischemia-reperfusion injury (CIRI) is a common and debilitating complication of cerebrovascular diseases such as stroke, characterized by mitochondrial dysfunction and cell apoptosis. Unraveling the molecular mechanisms behind these processes is essential for developing effective CIRI treatments. This study investigates the role of RACK1 (receptor for activated C kinase 1) in CIRI and its impact on mitochondrial autophagy.

METHODS

We utilized high-throughput transcriptome sequencing and weighted gene co-expression network analysis (WGCNA) to identify core genes associated with CIRI. In vitro experiments used human neuroblastoma SK-N-SH cells subjected to oxygen and glucose deprivation (OGD) to simulate ischemia, followed by reperfusion (OGD/R). RACK1 knockout cells were created using CRISPR/Cas9 technology, and cell viability, apoptosis, and mitochondrial function were assessed. In vivo experiments involved middle cerebral artery occlusion/reperfusion (MCAO/R) surgery in rats, evaluating neurological function and cell apoptosis.

RESULTS

Our findings revealed that RACK1 expression increases during CIRI and is protective by regulating mitochondrial autophagy through the PINK1/Parkin pathway. In vitro, RACK1 knockout exacerbated cell apoptosis, while overexpression of RACK1 reversed this process, enhancing mitochondrial function. In vivo, RACK1 overexpression reduced cerebral infarct volume and improved neurological deficits. The regulatory role of RACK1 depended on the PINK1/Parkin pathway, with RACK1 knockout inhibiting PINK1 and Parkin expression, while RACK1 overexpression restored them.

CONCLUSION

This study demonstrates that RACK1 safeguards against neural damage in CIRI by promoting mitochondrial autophagy through the PINK1/Parkin pathway. These findings offer crucial insights into the regulation of mitochondrial autophagy and cell apoptosis by RACK1, providing a promising foundation for future CIRI treatments.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

Dietary Selenium Insufficiency Induces Cardiac Inflammatory Injury in Chicks

BACKGROUND

Laying hens undergo intensive metabolism and are vulnerable to cardiac insults. Previous research demonstrated overt heart disorders of broiler chickens induced by dietary Se deficiency.

OBJECTIVES

This study aimed to reveal effects and mechanism of dietary Se insufficiency on cardiac injuries of egg-type chicks in their early life.

METHODS

White Leghorn chicks (0-d-old, female) were fed a corn-soy, Se-insufficient basal diet (BD, 0.05 mg Se/kg; n = 11) or the BD supplemented with 0.3 mg Se/kg (as sodium selenite; n = 8) for 35 d. Cardiac tissues were collected at the end of study for histology and to determine its relationship with heart Se contents, selenoprotein expression profiles, antioxidant and inflammatory status, and the Toll-like receptor 4/extracellular signal-regulated kinases/p38 map kinase/c-Jun N-terminal kinase (TLR4/ERK/P38/JNK) pathway.

RESULTS

Compared with those fed 0.35 mg Se/kg, chicks fed BD had significantly lower body weights and average daily gain, and 28% lower heart Se, and developed cardiac mononuclear inflammatory cell infiltration, along with elevated (P < 0.05) serum concentrations of creatine kinase, aldolase, and interleukin-1 (IL-1). The BD decreased (P < 0.05) body weight and heart glutathione contents and expression of selenoproteins but increased (P < 0.05) heart concentrations of malondialdehyde and reactive oxygen species. These changes were associated with increased (P < 0.05) mRNA and/or protein concentrations of cyclooxygenases, lipoxygenase-12, cytokines (IL-1β), nuclear factor (NF) κB subunit, chemokines, and receptors (CCL20, CXCR1, and CXCLI2) and increased (P < 0.1) TLR4/ERK /P38/JNK in the heart of Se-insufficient chicks.

CONCLUSIONS

Dietary Se insufficiency induces infiltration of mononuclear inflammatory cells in the heart of egg-type chicks. This cardiac injury was mediated by decreased functional expressions of selenoproteins, which resulted in apparent elevated oxidative stress and subsequent activations of the TLR4 pathway and NF κB.

Role of NLRP3 inflammasome in central nervous system diseases

The central nervous system (CNS) is the most delicate system in human body, with the most complex structure and function. It is vulnerable to trauma, infection, neurodegeneration and autoimmune diseases, and activates the immune system. An appropriate inflammatory response contributes to defence against invading microbes, whereas an excessive inflammatory response can aggravate tissue damage. The NLRP3 inflammasome was the first one studied in the brain. Once primed and activated, it completes the assembly of inflammasome (sensor NLRP3, adaptor ASC, and effector caspase-1), leading to caspase-1 activation and increased release of downstream inflammatory cytokines, as well as to pyroptosis. Cumulative studies have confirmed that NLRP3 plays an important role in regulating innate immunity and autoimmune diseases, and its inhibitors have shown good efficacy in animal models of various inflammatory diseases. In this review, we will briefly discuss the biological characteristics of NLRP3 inflammasome, summarize the recent advances and clinical impact of the NLRP3 inflammasome in infectious, inflammatory, immune, degenerative, genetic, and vascular diseases of CNS, and discuss the potential and challenges of NLRP3 as a therapeutic target for CNS diseases.

2,3,7,8-Tetrachlorodibenzo-p-dioxin and kynurenine induce Parkin expression in neuroblastoma cells through different signaling pathways mediated by the aryl hydrocarbon receptor

Parkin regulates protein degradation and mitophagy in dopaminergic neurons. Deficiencies in Parkin expression or function lead to cellular stress, cell degeneration, and the death of dopaminergic neurons, which promotes Parkinson's disease. In contrast, Parkin overexpression promotes neuronal survival. Therefore, the mechanisms of Parkin upregulation are crucial to understand. We describe here the molecular mechanism of AHR-mediated Parkin regulation in human SH-SY5Y neuroblastoma cells. Specifically, we report that the human Parkin gene (PRKN) is transcriptionally upregulated by the aryl hydrocarbon receptor (AHR) through two different selective ligand-dependent pathways. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a stress-inducing AHR ligand, indirectly promotes PRKN transcription by inducing ATF4 expression via TCDD-mediated endoplasmic reticulum (ER) stress. In contrast, kynurenine, a nontoxic AHR agonist, induces PRKN transcription by promoting AHR binding to the PRKN promoter without activating ER stress. Our results demonstrate that AHR activation may be a potential pharmacological pathway to induce human Parkin, but such a strategy must carefully consider the choice of AHR ligand to avoid neurotoxic side effects.

The Role of Astrocytic Mitochondria in the Pathogenesis of Brain Ischemia

The morbidity rate of ischemic stroke is increasing annually with the growing aging population in China. Astrocytes are ubiquitous glial cells in the brain and play a crucial role in supporting neuronal function and metabolism. Increasing evidence shows that the impairment or loss of astrocytes contributes to neuronal dysfunction during cerebral ischemic injury. The mitochondrion is increasingly recognized as a key player in regulating astrocyte function. Changes in astrocytic mitochondrial function appear to be closely linked to the homeostasis imbalance defects in glutamate metabolism, Ca2+ regulation, fatty acid metabolism, reactive oxygen species, inflammation, and copper regulation. Here, we discuss the role of astrocytic mitochondria in the pathogenesis of brain ischemic injury and their potential as a therapeutic target.

Involvement of Fgf2-mediated tau protein phosphorylation in cognitive deficits induced by sevoflurane in aged rats

OBJECTIVE

Anesthetics have been linked to cognitive alterations, particularly in the elderly. The current research delineates how Fibroblast Growth Factor 2 (Fgf2) modulates tau protein phosphorylation, contributing to cognitive impairments in aged rats upon sevoflurane administration.

METHODS

Rats aged 3, 12, and 18 months were subjected to a 2.5% sevoflurane exposure to form a neurotoxicity model. Cognitive performance was gauged, and the GEO database was employed to identify differentially expressed genes (DEGs) in the 18-month-old cohort post sevoflurane exposure. Bioinformatics tools, inclusive of STRING and GeneCards, facilitated detailed analysis. Experimental validations, both in vivo and in vitro, examined Fgf2's effect on tau phosphorylation.

RESULTS

Sevoflurane notably altered cognitive behavior in older rats. Out of 128 DEGs discerned, Fgf2 stood out as instrumental in regulating tau protein phosphorylation. Sevoflurane exposure spiked Fgf2 expression in cortical neurons, intensifying tau phosphorylation via the PI3K/AKT/Gsk3b trajectory. Diminishing Fgf2 expression correspondingly curtailed tau phosphorylation, neurofibrillary tangles, and enhanced cognitive capacities in aged rats.

CONCLUSION

Sevoflurane elicits a surge in Fgf2 expression in aging rats, directing tau protein phosphorylation through the PI3K/AKT/Gsk3b route, instigating cognitive aberrations.

Ferroptosis and endoplasmic reticulum stress in ischemic stroke

Ferroptosis is a form of non-apoptotic programmed cell death, and its mechanisms mainly involve the accumulation of lipid peroxides, imbalance in the amino acid antioxidant system, and disordered iron metabolism. The primary organelle responsible for coordinating external challenges and internal cell demands is the endoplasmic reticulum, and the progression of inflammatory diseases can trigger endoplasmic reticulum stress. Evidence has suggested that ferroptosis may share pathways or interact with endoplasmic reticulum stress in many diseases and plays a role in cell survival. Ferroptosis and endoplasmic reticulum stress may occur after ischemic stroke. However, there are few reports on the interactions of ferroptosis and endoplasmic reticulum stress with ischemic stroke. This review summarized the recent research on the relationships between ferroptosis and endoplasmic reticulum stress and ischemic stroke, aiming to provide a reference for developing treatments for ischemic stroke.

Therapeutic strategies targeting the NLRP3‑mediated inflammatory response and pyroptosis in cerebral ischemia/reperfusion injury (Review)

Ischemic stroke poses a major threat to human health. Therefore, the molecular mechanisms of cerebral ischemia/reperfusion injury (CIRI) need to be further clarified, and the associated treatment approaches require exploration. The NOD‑like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome serves an important role in causing CIRI, and its activation exacerbates the underlying injury. Activation of the NLRP3 inflammasome triggers the maturation and production of the inflammatory molecules IL‑1β and IL‑18, as well as gasdermin‑D‑mediated pyroptosis and CIRI damage. Thus, the NLRP3 inflammasome may be a viable target for the treatment of CIRI. In the present review, the mechanisms of the NLRP3 inflammasome in the intense inflammatory response and pyroptosis induced by CIRI are discussed, and the therapeutic strategies that target the NLRP3‑mediated inflammatory response and pyroptosis in CIRI are summarized. At present, certain drugs have already been studied, highlighting future therapeutic perspectives.

Parkin is a critical player in the effects of caffeine over mitochondrial quality control pathways during skeletal muscle regeneration in mice

AIM

This study aimed to investigate the effects of caffeine on pathways associated with mitochondrial quality control and mitochondrial capacity during skeletal muscle regeneration, focusing on the role of Parkin, a key protein involved in mitophagy.

METHODS

We used in vitro C2C12 myoblast during differentiation with and without caffeine in the medium, and we evaluated several markers of mitochondrial quality control pathways and myotube growth. In vivo experiments, we used C57BL/6J (WT) and Parkintm 1Shn lineage (Parkin-/- ) mice and injured tibial anterior muscle. The mice regenerated TA muscle for 3, 10, and 21 days with or without caffeine ingestion. TA muscle was used to analyze the protein content of several markers of mitochondrial quality pathways, muscle satellite cell differentiation, and protein synthesis. Furthermore, it analyzed mtDNA, mitochondrial respiration, and myofiber growth.

RESULTS

C2C12 differentiation experiments showed that caffeine decreased Parkin content, potentially leading to increased DRP1 and PGC-1α content and altered mitochondrial population, thereby enhancing growth capacity. Using Parkin-/- mice, we found that caffeine intake during the regenerative process induces an increase in AMPKα phosphorylation and PGC-1α and TFAM content, changes that were partly Parkin-dependent. In addition, the absence of Parkin potentiates the ergogenic effect of caffeine by increasing mitochondrial capacity and myotube growth. Those effects are related to increased ATF4 content and activation of protein synthesis pathways, such as increased 4E-BP1 phosphorylation.

CONCLUSION

These findings demonstrate that caffeine ingestion changes mitochondrial quality control during skeletal muscle regeneration, and Parkin is a central player in those mechanisms.

Hypoxia and its effect on the cellular system

Eukaryotic cells utilize oxygen for different functions of cell organelles owing to cellular survival. A balanced oxygen homeostasis is an essential requirement to maintain the regulation of normal cellular systems. Any changes in the oxygen level are stressful and can alter the expression of different homeostasis regulatory genes and proteins. Lack of oxygen or hypoxia results in oxidative stress and formation of hypoxia inducible factors (HIF) and reactive oxygen species (ROS). Substantial cellular damages due to hypoxia have been reported to play a major role in various pathological conditions. There are different studies which demonstrated that the functions of cellular system are disrupted by hypoxia. Currently, study on cellular effects following hypoxia is an important field of research as it not only helps to decipher different signaling pathway modulation, but also helps to explore novel therapeutic strategies. On the basis of the beneficial effect of hypoxia preconditioning of cellular organelles, many therapeutic investigations are ongoing as a promising disease management strategy in near future. Hence, the present review discusses about the effects of hypoxia on different cellular organelles, mechanisms and their involvement in the progression of different diseases.

NLRP6 deficiency inhibits neuroinflammation and ameliorates brain injury in ischemic stroke by blocking NLRs inflammasomes activation through proteasomal degradation of pro-caspase-1

Innate inflammation is crucial for ischemic stroke development. NLRP6, a nucleotide-binding and oligomerization domain-like receptors (NLRs) family member, regulates innate inflammation. Whether NLRP6 regulates neurological damage and neuroinflammation during ischemic stroke remains unclear. We report that NLRP6 is abundantly expressed in microglia and significantly upregulated in the ischemic brain. The brain injury severity was alleviated in NLRP6-deficient mice after ischemic stroke, as evidenced by reduced cerebral infarct volume, decreased neurological deficit scores, improved histopathological morphological changes, ameliorated neuronal denaturation, and relief of sensorimotor dysfunction. In the co-culture OGD/R model, NLRP6 deficiency prevented neuronal death and attenuated microglial cell injury. NLRP6 deficiency blocked several NLRs inflammasomes' activation and abrogated inflammasome-related cytokine production by decreasing the expression of the common effector pro-caspase-1. NLRP6 deficiency reduced pro-caspase-1's protein level by inducing proteasomal degradation. These findings confirm the neuroprotective role of NLRP6 deficiency in ischemic stroke and its underlying regulation mechanism in neuroinflammation and provide a potential therapeutic target for ischemic stroke.

CD30 protects EBV-positive diffuse large B-cell lymphoma cells against mitochondrial dysfunction through BNIP3-mediated mitophagy

Epstein-Barr virus (EBV) positive diffuse large B-cell lymphoma (EBV+ DLBCL) predicts poor prognosis and CD30 expression aggravates the worse consequences. Here, we reported that CD30 positivity was an independent prognostic indicator in EBV+ DLBCL patients in a retrospective cohort study. We harnessed CRISPR/Cas9 editing to engineer the first loss-of-function models of CD30 deficiency to identify that CD30 was critical for EBV+ DLBCL growth and survival. We established a pathway that EBV infection mediated CD30 expression through EBV-encoded latent membrane protein 1 (LMP1), which involved NF-κB signaling. CRISPR CD30 knockout significantly repressed BCL2 interacting protein 3 (BNIP3) expression and co-IP assay indicated a binding between CD30 and BNIP3. Moreover, silencing of CD30 induced mitochondrial dysfunction and suppressed mitophagy, resulting in the accumulation of damaged mitochondria by depressing BNIP3 expression. Additionally, CRISPR BNIP3 knockout caused proliferation defects and increased sensitivity to apoptosis. All the findings reveal a strong relationship between mitophagy and adverse prognosis of EBV+ DLBCL and discover a new regulatory mechanism of BNIP3-mediated mitophagy, which may help develop effective treatment regimens with anti-CD30 antibody brentuximab vedotin to improve the prognosis of CD30+ EBV+ DLBCL patients.

Mitochondrial stress: a key role of neuroinflammation in stroke

Stroke is a clinical syndrome characterized by an acute, focal neurological deficit, primarily caused by the occlusion or rupture of cerebral blood vessels. In stroke, neuroinflammation emerges as a pivotal event contributing to neuronal cell death. The occurrence and progression of neuroinflammation entail intricate processes, prominently featuring mitochondrial dysfunction and adaptive responses. Mitochondria, a double membrane-bound organelle are recognized as the "energy workshop" of the body. Brain is particularly vulnerable to mitochondrial disturbances due to its high energy demands from mitochondria-related energy production. The interplay between mitochondria and neuroinflammation plays a significant role in the pathogenesis of stroke. The biological and pathological consequences resulting from mitochondrial stress have substantial implications for cerebral function. Mitochondrial stress serves as an adaptive mechanism aimed at mitigating the stress induced by the import of misfolded proteins, which occurs in response to stroke. This adaptive response involves a reduction in misfolded protein accumulation and overall protein synthesis. The influence of mitochondrial stress on the pathological state of stroke is underscored by its capacity to interact with neuroinflammation. The impact of mitochondrial stress on neuroinflammation varies according to its severity. Moderate mitochondrial stress can bolster cellular adaptive defenses, enabling cells to better withstand detrimental stressors. In contrast, sustained and excessive mitochondrial stress detrimentally affects cellular and tissue integrity. The relationship between neuroinflammation and mitochondrial stress depends on the degree of mitochondrial stress present. Understanding its role in stroke pathogenesis is instrumental in excavating the novel treatment of stroke. This review aims to provide the evaluation of the cross-talk between mitochondrial stress and neuroinflammation within the context of stroke. We aim to reveal how mitochondrial stress affects neuroinflammation environment in stroke.

Anesthesia/surgery-induced learning and memory dysfunction by inhibiting mitophagy-mediated NLRP3 inflammasome inactivation in aged mice

Postoperative cognitive dysfunction (POCD) is a common postoperative complication, not only affects the quality of life of the elderly and increases the mortality rate, but also brings a greater burden to the family and society. Previous studies demonstrated that Nod-like receptor protein 3 (NLRP3) inflammasome participates in various inflammatory and neurodegenerative diseases. However, possible mitophagy mechanism in anesthesia/surgery-elicited NLRP3 inflammasome activation remains to be elucidated. Hence, this study clarified whether mitophagy dysfunction is related to anesthesia/surgery-elicited NLRP3 inflammasome activation. POCD model was established in aged C57BL/6 J mice by tibial fracture fixation under isoflurane anesthesia. Morris Water Maze (MWM) was used to evaluate learning and memory abilities. We found that in vitro experiments, lipopolysaccharide (LPS) significantly facilitated NLRP3 inflammasome activation and mitophagy inhibition in BV2 cells. Rapamycin restored mitophagy and improved mitochondrial function, and inhibited NLRP3 inflammasome activation induced by LPS. In vivo experiments, anesthesia and surgery caused upregulation of hippocampal NLRP3, caspase recruitment domain (ASC) and interleukin-1β (IL-1 β), and downregulation of microtubule-associated protein light chain 3II (LC3II) and Beclin1 in aged mice. Olaparib inhibited anesthesia/surgery-induced NLRP3, ASC, and IL-1β over-expression in the hippocampus, while upregulated the expression of LC3II and Beclin1. Furthermore, Olaparib improved cognitive impairment in older mice. These results revealed that mitophagy was involved in NLRP3 inflammasome-mediated anesthesia/surgery-induced cognitive deficits in aged mice. Overall, our results suggested that mitophagy was related in NLRP3 inflammasome-induced cognitive deficits after anesthesia and surgery in aged mice. Activating mitophagy may have clinical benefits in the prevention of cognitive impairment induced by anesthesia and surgery in elderly patients.

Parkin-mediated mitophagy protects against aluminum trichloride-induced hippocampal apoptosis in mice via the mtROS-NLRP3 pathway

Aluminum is a neurotoxic food contaminant. Aluminum trichloride (AlCl3) causes hippocampal mitochondrial damage, leading to hippocampal injury. Damaged mitochondria can release mitochondrial reactive oxygen species (mtROS) and activate nucleotide-binding oligomerization domain-like receptor-containing 3 (NLRP3) inflammasomes and apoptosis. E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy can attenuate mitochondrial damage. However, the role of mitophagy in AlCl3-induced mice hippocampal damage and its regulatory mechanism remain elusive. First, C57BL/6 N mice were treated with 0, 44.825, 89.65, and 179.3 mg/kg body weight AlCl3 drinking water for 90 d. Apoptosis, NLRP3-inflammasome activation and mitochondrial damage were increased in AlCl3-induced hippocampal damage. In addition, Parkin-mediated mitophagy peaked in the middle-dose group and was slightly attenuated in the high-dose group. Subsequently, we used wild-type and Parkin knockout (Parkin-/-) mice to investigate the AlCl3-induced hippocampal damage. The results showed that Parkin-/- inhibited mitophagy, and aggravated AlCl3-induced mitochondrial damage, NLRP3-inflammasome activation, apoptosis and hippocampal damage. Finally, we administered MitoQ (mtROS inhibitor) and MCC950 (NLRP3 inhibitor) to AlCl3-treated Parkin-/- mice to investigate the mechanism of Parkin-mediated mitophagy. The results showed that inhibition of mtROS and NLRP3 attenuated hippocampal NLRP3-inflammasome activation, apoptosis, and damage in AlCl3-treated Parkin-/- mice. These findings indicate that Parkin-mediated mitophagy protects against AlCl3-induced hippocampal apoptosis in mice via the mtROS-NLRP3 pathway.

Cross-talk between bioactive lipid mediators and the unfolded protein response in ischemic stroke

Ischemic cerebral stroke is a severe medical condition that affects about 15 million people every year and is the second leading cause of death and disability globally. Ischemic stroke results in neuronal cell death and neurological impairment. Current therapies may not adequately address the deleterious metabolic changes and may increase neurological damage. Oxygen and nutrient depletion along with the tissue damage result in endoplasmic reticulum (ER) stress, including the Unfolded Protein Response (UPR), and neuroinflammation in the affected area and cause cell death in the lesion core. The spatio-temporal production of lipid mediators, either pro-inflammatory or pro-resolving, decides the course and outcome of stroke. The modulation of the UPR as well as the resolution of inflammation promotes post-stroke cellular viability and neuroprotection. However, studies about the interplay between the UPR and bioactive lipid mediators remain elusive and this review gives insights about the crosstalk between lipid mediators and the UPR in ischemic stroke. Overall, the treatment of ischemic stroke is often inadequate due to lack of effective drugs, thus, this review will provide novel therapeutical strategies that could promote the functional recovery from ischemic stroke.

Activated AMPK Protects Against Chronic Cerebral Ischemia in Bilateral Carotid Artery Stenosis Mice

AMP-activated protein kinase (AMPK) is a regulator of cellular energy metabolism. Long-term use of metformin, an AMPK activator, was previously reported to be neuroprotective, as it promotes behavioral improvement and angiogenesis following an acute ischemic injury of the brain. However, only a few studies have demonstrated the role of AMPK in alleviating chronic cerebral ischemia (CCI) in mice models in the long-term (over 3 months). Therefore, we established a mouse model of CCI via bilateral carotid artery stenosis (BCAS) to explore the effect of AMPK on CCI. We used four groups of 3-month-old male C57BL/6 mice labeled as Sham, BCAS, BCAS + metformin treatment (BCAS + Met) and BCAS + AMPKα2 gene knockout (BCAS + KO). Three months after BCAS, we measured the AMPK protein expression, spatial learning and memory, Nissl bodies, cell apoptosis, astrocyte activation, and oligodendrocyte maturation. Additionally, we observed the brain tissues for changes in cell morphology. We observed that mice in the BCAS group had impaired spatial learning and memory compared with those in the sham group. The brain tissues of mice with CCI injury showed altered cell morphology, fewer Nissl bodies, cerebral cells apoptosis, and astrocyte activation. Interestingly, compared with mice from the BCAS group, the brains of mice from BCAS + Met group suffered lesser damage, whereas those of mice from the BCAS + KO group suffered more damage. The activation of AMPK, especially AMPKα2, plays a neuroprotective role during CCI in a mouse model of BCAS.

Buyang Huanwu Decoction alleviates cerebral ischemic injury through modulating caveolin-1-mediated mitochondrial quality control

Introduction: Mitochondrial quality control (MQC) is an important mechanism of neural repair after cerebral ischemia (CI). Recent studies have shown that caveolin-1 (Cav-1) is an important signaling molecule in the process of CI injury, but its mechanism of regulating MQC after CI is still unclear. Buyang Huanwu Decoction (BHD) is a classic traditional Chinese medicine formula that is often used to treat CI. Unfortunately, its mechanism of action is still obscure. Methods: In this study, we tested the hypothesis that BHD can regulate MQC through Cav-1 and exert an anti-cerebral ischemia injury effect. We used Cav-1 knockout mice and their homologous wild-type mice, replicated middle cerebral artery occlusion (MCAO) model and BHD intervention. Neurobehavioral scores and pathological detection were used to evaluate neurological function and neuron damage, transmission electron microscopy and enzymology detection of mitochondrial damage. Finally, western blot and RT-qPCR expression of MQC-related molecules were tested. Results: After CI, mice showed neurologic impairment, neuronal damage, and significant destruction of mitochondrial morphology and function, and MQC was imbalanced. Cav-1 deletion aggravated the damage to neurological function, neurons, mitochondrial morphology and mitochondrial function after CI, aggravated the imbalance of mitochondrial dynamics, and inhibited mitophagy and biosynthesis. BHD can maintain MQC homeostasis after CI through Cav-1 and improve CI injury. Discussion: Cav-1 can affect CI injury by regulating MQC, and this mechanism may be another target of BHD for anti-cerebral ischemia injury.

Insight into the transcription factors regulating Ischemic Stroke and Glioma in Response to Shared Stimuli

Cerebral ischemic stroke and glioma are the two leading causes of patient mortality globally. Despite physiological variations, 1 in 10 people who have an ischemic stroke go on to develop brain cancer, most notably gliomas. In addition, glioma treatments have also been shown to increase the risk of ischemic strokes. Stroke occurs more frequently in cancer patients than in the general population, according to traditional literature. Unbelievably, these events share multiple pathways, but the precise mechanism underlying their co-occurrence remains unknown. Transcription factors (TFs), the main components of gene expression programmes, finally determine the fate of cells and homeostasis. Both ischemic stroke and glioma exhibit aberrant expression of a large number of TFs, which are strongly linked to the pathophysiology and progression of both diseases. The precise genomic binding locations of TFs and how TF binding ultimately relates to transcriptional regulation remain elusive despite a strong interest in understanding how TFs regulate gene expression in both stroke and glioma. As a result, the importance of continuing efforts to understand TF-mediated gene regulation is highlighted in this review, along with some of the primary shared events in stroke and glioma.

Polydatin inhibits mitochondrial damage and mitochondrial ROS by promoting PINK1-Parkin-mediated mitophagy in allergic rhinitis

Polydatin (PD), a natural product derived from Polygonum cuspidatum, has anti-inflammatory and antioxidant effects and has significant benefits in treating allergic diseases. However, its role and mechanism in allergic rhinitis (AR) have not been fully elucidated. Herein, we investigated the effect and mechanism of PD in AR. AR model was established in mice with OVA. Human nasal epithelial cells (HNEpCs) were stimulated with IL-13. HNEpCs were also treated with an inhibitor of mitochondrial division or transfected with siRNA. The levels of IgE and cellular inflammatory factors were examined by enzyme linked immunosorbent assay and flow cytometry. The expressions of PINK1, Parkin, P62, LC3B, NLRP3 inflammasome proteins, and apoptosis proteins in nasal tissues and HNEpCs were measured by Western blot. We found that PD suppressed OVA-induced epithelial thickening and eosinophil accumulation in the nasal mucosa, reduced IL-4 production in NALF, and regulated Th1/Th2 balance. In addition, mitophagy was induced in AR mice after OVA challenge and in HNEpCs after IL-13 stimulation. Meanwhile, PD enhanced PINK1-Parkin-mediated mitophagy but decreased mitochondrial reactive oxygen species (mtROS) production, NLRP3 inflammasome activation, and apoptosis. However, PD-induced mitophagy was abrogated after PINK1 knockdown or Mdivi-1 treatment, indicating a key role of the PINK1-Parkin in PD-induced mitophagy. Moreover, mitochondrial damage, mtROS production, NLRP3 inflammasome activation, and HNEpCs apoptosis under IL-13 exposure were more severe after PINK1 knockdown or Mdivi-1 treatment. Conclusively, PD may exert protective effects on AR by promoting PINK1-Parkin-mediated mitophagy, which further suppresses apoptosis and tissue damage in AR through decreasing mtROS production and NLRP3 inflammasome activation.

Anti-Ferroptotic Effects of bone Marrow Mesenchymal Stem Cell-Derived Extracellular Vesicles Loaded with Ferrostatin-1 in Cerebral ischemia-reperfusion Injury Associate with the GPX4/COX-2 Axis

Accumulating evidence of the critical role of Ferrostatin-1 (Fer-1, ferroptosis inhibitor) in cerebral ischemia has intrigued us to explore the molecular mechanistic actions of Fer-1 delivery by bone marrow mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) in cerebral ischemia-reperfusion (I/R) injury. In vivo middle cerebral artery occlusion (MCAO) in mice and in vitro oxygen-glucose deprivation/reperfusion (OGD/R) in hippocampal neurons were developed to simulate cerebral I/R injury. After Fer-1 was confirmed to be successfully delivered by MSCs-EVs to neurons, we found that MSCs-EVs loaded with Fer-1 (MSCs-EVs/Fer-1) reduced neuron apoptosis and enhanced viability, along with curtailed inflammation and ferroptosis. The regulation of Fer-1 on GPX4/COX2 axis was predicted by bioinformatics study and validated by functional experiments. The in vivo experiments further confirmed that MSCs-EVs/Fer-1 ameliorated cerebral I/R injury in mice. Furthermore, poor expression of GPX4 and high expression of COX-2 were witnessed in cerebral I/R injury models. MSCs-EVs/Fer-1 exerted its protective effects against cerebral I/R injury by upregulating GPX4 expression and inhibiting COX-2 expression. Taken together, our study indicates that MSCs-EVs/Fer-1 may be an attractive therapeutic target for the treatment of cerebral I/R injury due to its anti-ferroptotic properties.

Protection of Taohong Siwu Decoction on PC12 cells injured by oxygen glucose deprivation/reperfusion via mitophagy-NLRP3 inflammasome pathway in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Taohong Siwu Decoction (THSWD) is a traditional Chinese medicine formula used to invigorate blood circulation and resolve blood stasis. It consists of Paeonia lactiflora Pall., Conioselinum anthriscoides (H.Boissieu) Pimenov & Kljuykov, Rehmannia glutinosa (Gaertn.) DC., Prunus persica (L.) Batsch, Angelica sinensis (Oliv.) Diels, and Carthamus creticus L. in the ratio of 3:2:4:3:3:2. THSWD is a common prescription for the treatment of ischemic stroke.

AIM OF THE STUDY

To study the protective effect and mechanism of Taohong Siwu Decoction (THSWD) on PC12 cells damaged by oxygen glucose deprivation/reperfusion (OGD/R).

MATERIALS AND METHODS

OGD/R model of PC12 cells was used to simulate ischemia-reperfusion (I/R) injury of nerve cells in vitro. The experiment was grouped as follows: control, OGD/R and OGD/R + THSWD (5%, 10% and 15%) group. Oxygen and glucose was restored for 24 h after 4-6 h of deprivation. The severity of damage to PC12 cells was evaluated by CCK8, flow cytometry and lactate dehydrogenase (LDH). Mitochondrial morphology and function were examined by transmission electron microscopy (TEM), ATP and mitochondrial membrane potential (MMP) assay kits. Cellular autophagy and NLRP3 inflammasome-associated proteins were detected by Western blot and immunofluorescence staining.

RESULTS

THSWD treatment improved the survival rate of PC12 cells injured by OGD/R, reduced cell damage and apoptosis. Moreover, ATP, MMP and the expression of autophagy marker proteins (LC3-II/LC3-I, Beclin1, Atg5) and mitophagy marker proteins (Parkin and PINK-1) was significantly elevated. The reactive oxygen species (ROS), NLRP3 inflammasome and pro-inflammatory cytokines induced by OGD/R were distinctly reduced. In contrast, these above beneficial effects of THSWD on mitochondrial autophagy and NLRP3 inflammasome were reversed by mitochondrial division inhibitory factor 1 (Mdivi-1).

CONCLUSION

THSWD protects PC12 cells against OGD/R injury by heightening mitophagy and suppressing the activation of NLRP3 inflammasome.

RGD1564534 represses NLRP3 inflammasome activity in cerebral injury following ischemia-reperfusion by impairing miR-101a-3p-mediated Dusp1 inhibition

BACKGROUND

Mitochondrial autophagy, the elimination of damaged mitochondria through autophagy, contributes to neuron survival in cerebral ischemia. Long non-coding RNAs (lncRNAs)/microRNAs (miRNAs)/mRNAs are important regulatory networks implicated in various biological processes, including cerebral ischemia-reperfusion (I/R) injury. Therefore, this work clarifies a novel RGD1564534-mediated regulatory network on mitochondrial autophagy in cerebral I/R injury.

METHODS

Differentially expressed lncRNAs in cerebral I/R injury were predicted by bioinformatics analysis. Expression of RGD1564534 was examined in the established middle cerebral artery occlusion (MCAO) rats and oxygen glucose deprivation/reoxygenation (OGD/R)-exposed neurons. We conducted luciferase activity, RNA pull-down and RIP assays to illustrate the interaction among RGD1564534, miR-101a-3p and Dusp1. Gain- or loss-of-function approaches were used to manipulate RGD1564534 and Dusp1 expression. The mechanism of RGD1564534 in cerebral I/R injury was evaluated both in vivo and in vitro.

RESULTS

RGD1564534 was poorly expressed in the MCAO rats and OGD/R-treated cells, while its high expression attenuated nerve damage, cognitive dysfunction, brain white matter and small vessel damage in MCAO rats. In addition, RGD1564534 promoted mitochondrial autophagy and inhibited NLRP3 inflammasome activity. RGD1564534 competitively bound to miR-101a-3p and attenuated its binding to Dusp1, increasing the expression of Dusp1 in neurons. By this mechanism, RGD1564534 enhanced mitochondrial autophagy, reduced NLRP3 inflammasome activity and suppressed the neuron apoptosis induced by OGD/R.

CONCLUSION

Altogether, RGD1564534 elevates the expression of Dusp1 by competitively binding to miR-101a-3p, which facilitates mitochondrial autophagy-mediated inactivation of NLRP3 inflammasome and thus retards cerebral I/R injury.

Relationship between ferroptosis and mitophagy in cardiac ischemia reperfusion injury: a mini-review

Cardiovascular diseases (CVD), with high morbidity and mortality, seriously affect people's life and social development. Clinically, reperfusion therapy is typically used to treat ischemic cardiomyopathy, such as severe coronary heart disease and acute myocardial infarction. However, reperfusion therapy can lead to myocardial ischemia reperfusion injury (MIRI), which can affect the prognosis of patients. Studying the mechanisms of MIRI can help us improve the treatment of MIRI. The pathological process of MIRI involves many mechanisms such as ferroptosis and mitophagy. Ferroptosis can exacerbate MIRI, and regulation of mitophagy can alleviate MIRI. Both ferroptosis and mitophagy are closely related to ROS, but there is no clear understanding of the relationship between ferroptosis and mitophagy. In this review, we analyzed the relationship between ferroptosis and mitophagy according to the role of mTOR, NLPR3 and HIF. In addition, simultaneous regulation of mitophagy and ferroptosis may be superior to single therapy for MIRI. We summarized potential drugs that can regulate mitophagy and/or ferroptosis, hoping to provide reference for the development of drugs and methods for MIRI treatment.

IKZF3 modulates cerebral ischemia/reperfusion injury by inhibiting neuroinflammation

Neuroinflammation is a key mediator to the pathogenic cascades induced by cerebral ischemia-reperfusion (I/R) injury. IKZF3, a key zinc finger transcription factor in the Ikaros family, has already been shown to modulate a wide range of cell functions and the production of inflammatory mediators. However, the effects of IKZF3 on inflammation and the potential mechanism after cerebral I/R injury remain unclear. In this study, we evaluated the effect of IKZF3 on HT-22 cells under oxygen-glucose deprivation and reoxygenation (OGD/R) in vitro and in mice with MACO in vivo. We found that IKZF3 expression peaked at 12 h after MCAO and OGD/R, and there was high expression of IKZF3 in brain tissues and HT-22 cells. IKZF3 knockdown exacerbated the damage by OGD-induced HT-22 cells injury and MCAO-induced brain injury in mice by regulating the production of inflammatory factors, which promoted the phosphorylation and nuclear transfer of NF-ĸB and may bind with NF-ĸB-p65 in vivo and in vitro. Our results suggested that IKZF3 may provide a new target in improve neurological recovery and reducing neuroinflammation after cerebral I/R injury.

Elevated SIRT3 Parkin-dependently activates cell mitophagy to ameliorate TNF-α-induced psoriasis-related phenotypes in HaCaT cells through deacetylating FOXO3a for its activation

Sirtuin 3 (SIRT3) is reported to be closely relevant to the pathogenesis of psoriasis, but its detailed functions and molecular mechanisms have not been fully studied. Thus, this study aimed to investigate the effects and underlying mechanisms by which SIRT3 regulated the development of psoriasis. Specifically, we verified that SIRT3 was aberrantly downregulated in psoriasis-like skin tissues in mice models in vivo and TNF-α-stimulated HaCaT cells in vitro, compared to their corresponding normal counterparts. Functional experiments confirmed that upregulation of SIRT3 triggered cell mitophagy, restrained oxidative stress and inflammation, and inhibited excessive cell proliferation in the TNF-α-stimulated HaCaT cells in vitro, which were all ablated by co-treating cells with the mitophagy inhibitor 3-MA. Subsequently, the mechanism experiments uncovered that elevated SIRT3 deacetylated forkhead box class o 3A (FOXO3a) for its activation, which further activated the Parkin-dependent cell mitophagy in the HaCaT cells. Next, through performing the rescuing experiments, we validated that SIRT3 ameliorated TNF-α-induced psoriasis-associated phenotypes in the HaCaT cells via modulating the FOXO3a/Parkin signal pathway. Collectively, we concluded that SIRT3 triggered cell mitophagy through activating the FOXO3a/Parkin pathway to ameliorate TNF-α-induced psoriasis in the HaCaT cells, and this study provided evidences to support that SIRT3 could be used as important therapeutic target for the treatment of psoriasis.

E3 Ubiquitin Ligase FBXO3 Drives Neuroinflammation to Aggravate Cerebral Ischemia/Reperfusion Injury

Ischemic stroke, one of the most universal causes of human mortality and morbidity, is pathologically characterized by inflammatory cascade, especially during the progression of ischemia/reperfusion (I/R) injury. F-Box Protein 3 (FBXO3), a substrate-recognition subunit of SKP1-cullin 1-F-box protein (SCF) E3 ligase complexes, has recently been proven to be severed as an underlying pro-inflammatory factor in pathological processes of diverse diseases. Given these considerations, the current study aims at investigating whether FBXO3 exerts impacts on inflammation in cerebral I/R injury. In this study, first, it was verified that FBXO3 protein expression increased after a middle cerebral artery occlusion/reperfusion (MCAO/R) model in Sprague-Dawley (SD) rats and was specifically expressed in neurons other than microglia or astrocytes. Meanwhile, in mouse hippocampal neuronal cell line HT22 cells, the elevation of FBXO3 protein was observed after oxygen and glucose deprivation/reoxygenation (OGD/R) treatment. It was also found that interference of FBXO3 with siRNA significantly alleviated neuronal damage via inhibiting the inflammatory response in I/R injury both in vivo and in vitro. The FBXO3 inhibitor BC-1215 was used to confirm the pro-inflammatory effect of FBXO3 in the OGD/R model as well. Furthermore, by administration of FBXO3 siRNA and BC-1215, FBXO3 was verified to reduce the protein level of Homeodomain-Interacting Protein Kinase 2 (HIPK2), likely through the ubiquitin-proteasome system (UPS), to aggravate cerebral I/R injury. Collectively, our results underline the detrimental effect FBXO3 has on cerebral I/R injury by accelerating inflammatory response, possibly through ubiquitylating and degrading HIPK2. Despite the specific interaction between FBXO3 and HIPK2 requiring further study, we believe that our data suggest the therapeutic relevance of FBXO3 to ischemic stroke and provide a new perspective on the mechanism of I/R injury.

Docosahexaenoic Acid Alleviates Brain Damage by Promoting Mitophagy in Mice with Ischaemic Stroke

Mitophagy, the selective removal of damaged mitochondria through autophagy, is crucial for mitochondrial turnover and quality control. Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects mitochondria in various diseases. This study aimed to investigate the neuroprotective role of DHA in ischaemic stroke models in vitro and in vivo and its involvement in mitophagy and mitochondrial dysfunction. A mouse model of ischaemic stroke was established through middle cerebral artery occlusion (MCAO). To simulate ischaemic stroke in vitro, PC12 cells were subjected to oxygen–glucose deprivation (OGD). Immunofluorescence analysis, western blotting (WB), electron microscopy (EM), functional behavioural tests, and Seahorse assay were used for analysis. DHA treatment significantly alleviated the brain infarction volume, neuronal apoptosis, and behavioural dysfunction in mice with ischaemic stroke. In addition, DHA enhanced mitophagy by significantly increasing the number of autophagosomes and LC3-positive mitochondria in neurons. The Seahorse assay revealed that DHA increased glutamate and succinate metabolism in neurons after ischaemic stroke. JC-1 and MitoSox staining, and evaluation of ATP levels indicated that DHA-induced mitophagy alleviated reactive oxygen species (ROS) accumulation and mitochondrial injury. Mechanistically, DHA improved mitochondrial dynamics by increasing the expression of dynamin-related protein 1 (Drp1), LC3, and the mitophagy clearance protein Pink1/Parkin. Mdivi-1, a specific mitophagy inhibitor, abrogated the neuroprotective effects of DHA, indicating that DHA protected neurons by enhancing mitophagy. Therefore, DHA can protect against neuronal apoptosis after stroke by clearing the damaged mitochondria through Pink1/Parkin-mediated mitophagy and by alleviating mitochondrial dysfunction.

Attenuation of Piwil2 induced by hypoxic postconditioning prevents cerebral ischemic injury by inhibiting CREB2 promoter methylation

Epigenetic modification contributes to the pathogenesis of cerebral ischemia. Piwil2 belongs to the PIWI proteins subfamily and has a key role in the regulation of gene transcription through epigenetics. However, the roles of Piwil2 in cerebral ischemia have not been investigated. In this study, we aim to elucidate the roles and the underlying molecular mechanisms of Piwil2 in ischemic tolerance induced by hypoxic postconditioning (HPC) against transient global cerebral ischemia (tGCI). We found that the expression of Piwil2 in CA1 was downregulated by HPC after tGCI. Silencing Piwil2 with antisense oligodeoxynucleotide (AS-ODN) in CA1 after tGCI decreased the expression of apoptosis-related proteins and exerted neuroprotective effects. Opposite results were observed after overexpression of Piwil2 induced by administration of Piwil2-carried lentivirus. Furthermore, we revealed differentially expressed Piwil2-interacting piRNAs in CA1 between HPC and tGCI groups by RNA binding protein immunoprecipitation (RIP) assay. Moreover, downregulating Piwil2 induced by HPC or AS-ODN after tGCI caused a marked reduction of DNA methyltransferase 3A (DNMT3A), which in turn abolished the tGCI-induced increase in the DNA methylation of cyclic AMP response element-binding 2 (CREB2), thus increasing mRNA and protein of CREB2. Finally, downregulating Piwil2 restored dendritic complexity and length, prevented the loss of dentritic spines, thereby improving cognitive function after tGCI. These data firstly reveal that Piwil2 plays an important part in HPC-mediated neuroprotection against cerebral ischemia through epigenetic regulation of CREB2.

Anfibatide alleviates inflammation and apoptosis via inhibiting NF-kappaB/NLRP3 axis in ischemic stroke

Recent evidence suggests that Nod-like receptor protein-3 (NLRP3) inflammasome is a key mediator of inflammatory response and can induce the activation of apoptosis signaling pathways in ischemic stroke. In this research, we assessed the effects of anfibatide (ANF) on inflammatory and apoptosis in cerebral ischemic injury and the potential mechanisms. Middle cerebral artery occlusion (MCAO) model was established on male Sprague-Dawley rats to induce cerebral ischemia/reperfusion (I/R) injury in vivo. Primary cortical neurons (PCN) cells were exposed to oxygen-glucose deprivation and reintroduction (OGD/R) to mimic cerebral I/R injury in vitro. The results showed that ANF markedly alleviated infarct volume, neurological deficit and neurobehavioral impairment in MCAO/R rats, enhanced cell viability and decreased LDH release in PCN after OGD/R. The number of TUNEL-positive cells, Bax, cleaved-caspase-3, p-IκBα, p-p65, NLRP3, ASC, cleaved caspase-1, IL-β and IL-18 proteins expression were significantly upregulated in the cortex of MCAO/R rats and PCN exposed to OGD/R, NLRP3 and caspase-1 mRNA levels were also evidently elevated. Bcl-2 protein expression significantly decreased in the cortex of MCAO/R rats. Treatment with ANF obviously inhibited the expression of p-IκBα, p-p65, NLRP3, ASC, cleaved caspase-1, Bax and cleaved-caspase-3, promoted the expression of Bcl-2, then decreased the TUNEL-positive cell number and the level of inflammatory cytokines (IL-β and IL-18) in cerebral ischemia reperfusion in vito and in vitro. Our findings suggest that ANF exerts effects of alleviating inflammation and apoptosis through inhibiting NF-kappaB/NLRP3 axis. ANF is a potential candidate for treating cerebral I/R injury.

Neuroprotective Effect of Taohong Siwu Decoction on Cerebral Ischemia/Reperfusion Injury via Mitophagy-NLRP3 Inflammasome Pathway

Objective: Globally, cerebral ischemia has been shown to be the second leading cause of death. Our previous studies have shown that Taohong Siwu Decoction (THSWD) exhibits obvious neuroprotective effects on cerebral ischemia/reperfusion (I/R) injury (CIRI). In this study, we further explored the modulatory effect of THSWD on mitochondrial autophagy in CIRI and the relationship between modulatory effect and NLRP3 inflammatory vesicle activation, so as to further explain the mechanism of neuroprotective effect of THSWD.

Methods: Middle cerebral artery occlusion reperfusion (MCAO/R) model in rats was built to simulate I/R. Adult male SD rats (220–270 g) were randomly divided into the following four groups: the sham group, the MCAO/R group, the MCAO/R + THSWD group, and the MCAO/R + THSWD + Mitochondrial division inhibitor 1 (Mdivi-1) group. Neurological defect scores were used to evaluate neurological function. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was conducted to measure cerebral infarct volume. Nissl staining, H&E staining and TUNEL staining were executed to detect ischemic cortical neuronal cell viability and apoptosis. Electron microscopy was used to observe the ultrastructural changes of mitochondria. Total Reactive Oxygen Species (ROS) in tissue were measured by fluorescence spectrophotometry, and the activation status of microglia was evaluated by Iba-1/CD16 immunofluorescence staining. The levels of mitophagy-related proteins (LC3, Parkin, PINK1), NLRP3 inflammasome-related proteins (NLRP3, ASC, Pro-caspase-1, Cleaved-caspase-1), and inflammatory cytokines (Pro-IL-18, Pro-IL-1β, IL-18, IL-1β) were evaluated by western blotting.

Results: The studies showed that THSWD treatment alleviated cerebral infarction and neurological deficiencies. THSWD upregulated the expressions of autophagy markers (LC3-II/LC3-I and Beclin1) mitochondrial autophagy markers (Parkin and PINK1) after CIRI. Furthermore, THSWD treatment attenuated microglia activation and damage to mitochondrial structures, thereby reducing ROS production and NLRP3 inflammasome activation. In contrast, the mitochondrial autophagy inhibitor Mdivi-1 inhibited the above beneficial effects of THSWD.

Conclusions: THSWD exhibits neuroprotective effects against MCAO/R in rats by enhancing mitochondrial autophagy and reducing NLRP3 inflammasome activation.

MSC-Derived Extracellular Vesicles Activate Mitophagy to Alleviate Renal Ischemia/Reperfusion Injury via the miR-223-3p/NLRP3 Axis

Background

MSC-derived extracellular vehicles (EVs) exhibit a protective functional role in renal ischemia/reperfusion injury (RIRI). Recent studies have revealed that mitophagy could be a potential target process in the treatment of RIRI. However, whether MSC-derived EVs are involved in the regulation of mitophagy in RIRI remains largely unknown to date.

Methods

RIRI model was established in vivo in mice by subjecting them to renal ischemia/reperfusion. TCMK-1 cells were subjected to hypoxia/reoxygenation (H/R) stimulation to mimic RIRI in vitro. BMSCs and BMSC-derived EVs were isolated and identified. Renal injury was assessed using H&E staining. The qPCR and western blot analyses were conducted to detect the mRNA and protein levels. Apoptosis was evaluated using the TUNEL assay and flow cytometry analysis. The EVs, autophagosomes, and mitochondria were observed using TEM. The colocalization of autophagosomes with mitochondria was confirmed through the confocal assay. The direct binding of miR-223-3p to NLRP3 was validated through the dual-luciferase assay.

Results

BMSCs and BMSC-derived EVs were successfully isolated from mice and identified. The protective effect of BMSC-derived EVs against RIRI was validated both in vitro and in vivo, which was indicated by a decrease in apoptosis and inflammasome activation and an increase in mitophagy. However, this protective effect was impaired in the miR-223-3p-depleted EVs, suggesting that miR-223-3p mediated this protective effect. Further mechanistic investigation revealed that miR-223-3p suppressed inflammasome activation to enhance mitophagy by directly targeting NLRP3.

Conclusion

In conclusion, the protective role of BMSC-derived EVs and exosome-delivered miR-223-3p in RIRI was validated. Exogenous miR-223-3p directly targeted NLRP3 to attenuate inflammasome activation, thereby promoting mitophagy.

SIK2 Improving Mitochondrial Autophagy Restriction Induced by Cerebral Ischemia-Reperfusion in Rats

Previous studies have shown that Salt-induced kinase-2(SIK2) is involved in the regulation of various energy-metabolism-related reactions, and it also can regulate angiogenesis after cerebral ischemia-reperfusion. However, it is unclear whether SIK2 can regulate energy metabolism in cerebral ischemia-reperfusion injury. As mitochondria plays an important role in energy metabolism, whether SIK2 regulates energy metabolism through affecting mitochondrial changes is also worth to be explored. In this study, rats were treated with adeno-associated virus-SIK2-Green fluorescent protein (AAV-SIK2-GFP) for the overexpression of SIK2 before middle cerebral artery occlusion (MCAO). We found that SIK2 overexpression could alleviate the neuronal damage, reduce the area of cerebral infarction, and increase the adenosine triphosphate (ATP) content, which could promote the expression of phosphorylated-mammalian target of rapamycin-1 (p-mTORC1), hypoxia-inducible factor-1α (HIF-1α), phosphatase and tensin homologue-induced putative kinase 1 (PINK1) and E3 ubiquitinligating enzyme (Parkin). Transmission electron microscopy revealed that SIK2 overexpression enhanced mitochondrial autophagy. It is concluded that SIK2 can ameliorate neuronal injury and promote the energy metabolism by regulating the mTOR pathway during cerebral ischemia-reperfusion, and this process is related to mitochondrial autophagy.

Mitochondrial Quality and Quantity Control: Mitophagy Is a Potential Therapeutic Target for Ischemic Stroke

Ischemic stroke is a cerebrovascular disease with high mortality and disability, which seriously affects the health and lives of people around the world. Effective treatment for ischemic stroke has been limited by its complex pathological mechanisms. Increasing evidence has indicated that mitochondrial dysfunction plays an essential role in the occurrence, development, and pathological processes of ischemic stroke. Therefore, strict control of the quality and quantity of mitochondria via mitochondrial fission and fusion as well as mitophagy is beneficial to the survival and normal function maintenance of neurons. Under certain circumstances, excessive mitophagy also could induce cell death. This review discusses the dynamic changes and double-edged roles of mitochondria and related signaling pathways of mitophagy in the pathophysiology of ischemic stroke. Furthermore, we focus on the possibility of modulating mitophagy as a potential therapy for the prevention and prognosis of ischemic stroke. Notably, we reviewed recent advances in the studies of natural compounds, which could modulate mitophagy and exhibit neuroprotective effects, and discussed their potential application in the treatment of ischemic stroke.

Endoplasmic Reticulum Stress-Associated Neuronal Death and Innate Immune Response in Neurological Diseases

Neuronal death and inflammatory response are two common pathological hallmarks of acute central nervous system injury and chronic degenerative disorders, both of which are closely related to cognitive and motor dysfunction associated with various neurological diseases. Neurological diseases are highly heterogeneous; however, they share a common pathogenesis, that is, the aberrant accumulation of misfolded/unfolded proteins within the endoplasmic reticulum (ER). Fortunately, the cell has intrinsic quality control mechanisms to maintain the proteostasis network, such as chaperone-mediated folding and ER-associated degradation. However, when these control mechanisms fail, misfolded/unfolded proteins accumulate in the ER lumen and contribute to ER stress. ER stress has been implicated in nearly all neurological diseases. ER stress initiates the unfolded protein response to restore proteostasis, and if the damage is irreversible, it elicits intracellular cascades of death and inflammation. With the growing appreciation of a functional association between ER stress and neurological diseases and with the improved understanding of the multiple underlying molecular mechanisms, pharmacological and genetic targeting of ER stress are beginning to emerge as therapeutic approaches for neurological diseases.

Role of Mitophagy in the Pathogenesis of Stroke: From Mechanism to Therapy

Mitochondria can supply adenosine triphosphate (ATP) to the tissue, which can regulate metabolism during the pathologic process and is also involved in the pathophysiology of neuronal injury after stroke. Recent studies have suggested that selective autophagy could play important roles in the pathophysiological process of stroke, especially mitophagy. It is usually mediated by the PINK1/Parkin-independent pathway or PINK1/Parkin-dependent pathway. Moreover, mitophagy may be a potential target in the therapy of stroke because the control of mitophagy is neuroprotective in stroke in vitro and in vivo. In this review, we briefly summarize recent researches in mitophagy, introduce the role of mitophagy in the pathogenesis of stroke, then highlight the strategies targeting mitophagy in the treatment of stroke, and finally propose several issues in the treatment of stroke by targeting mitophagy.

Emerging Roles and Mechanisms of lncRNA FOXD3-AS1 in Human Diseases

Numerous long noncoding RNAs (lncRNAs) have been identified as powerful regulators of human diseases. The lncRNA FOXD3-AS1 is a novel lncRNA that was recently shown to exert imperative roles in the initialization and progression of several diseases. Emerging studies have shown aberrant expression of FOXD3-AS1 and close correlation with pathophysiological traits of numerous diseases, particularly cancers. More importantly, FOXD3-AS1 was also found to ubiquitously impact a range of biological functions. This study aims to summarize the expression, associated clinicopathological features, major functions and molecular mechanisms of FOXD3-AS1 in human diseases and to explore its possible clinical applications.

Sigma-1 Receptor and Binding Immunoglobulin Protein Interact with Ulinastatin Contributing to a Protective Effect in Rat Cerebral Ischemia/Reperfusion

OBJECTIVE

To investigate impact of ulinastatin (UTI) on sigma-1 receptor (σ1R) and binding immunoglobulin protein (BiP) after cerebral ischemia/reperfusion injury.

METHODS

The middle cerebral artery occlusion (MCAO) model was used to induce cerebral ischemia/reperfusion injury. Eighty male Sprague Dawley rats were randomly divided into 6 groups: control, MCAO, MCAO+50,000 U/kg UTI, MCAO+100,000 U/kg UTI, MCAO+200,000 U/kg UTI, MCAO+300,000 U/kg UTI. At 24 and 48 hours after MCAO, infarct volume, neurological dysfunction, and grip strength test were measured, and level of σ1R and BiP proteins was further detected using Western blot. Molecular docking assays were carried out to verify interaction between σ1R, BiP, and UTI. The serum concentration of BiP and the binding assay between σ1R, BiP, and UTI were determined using enzyme-linked immunosorbent assay.

RESULTS

UTI increased the modified neurological severity score and upregulated σ1R and BiP expression in the cerebral cortex after MCAO. The grip strength of forelimbs increased significantly in the MCAO+200,000 U/kg UTI and MCAO+300,000 U/kg UTI groups compared with the MCAO group, while BiP serum levels remained unchanged. The molecular docking assay indicated putative binding between σ1R, BiP, and UTI. The binding assay also revealed that both σ1R and BiP could be combined with UTI.

CONCLUSIONS

UTI displays a neuroprotective effect via upregulation of σ1R and BiP during ischemia/reperfusion injury, suggesting that UTI modulates σ1R and BiP and their interaction may provide a novel insight into potential therapeutic mechanisms for stroke.

MicroRNA-32-5p attenuates cerebral ischemia/reperfusion injuries by modulating the phosphatase and tensin homologous protein

Non-coding RNAs have recently attracted much attention with the potential in the treatment of cerebral ischemia/reperfusion (I/R) injuries. In this study, we investigated the role of miR-32-5p in cerebral I/R injuries by using oxygen-glucose deprivation/reperfusion (OGD/R) PC12 cells and middle cerebral artery occlusion/reperfusion (MCAO/R) rats. The expression of genes and proteins were detected by RT-qPCR and Western blot, respectively. The function of OGD/R PC12 cells was detected using MTT assay and flow cytometry analysis. The influences of MCAO/R on rats was evaluated by measuring the infarct volume and brain water content. Bioinformatics analysis and luciferase gene reporter assay were used to identify the relationship between miR-32-5p and PTEN. The results showed that miR-32-5p had neuroprotective effects on OGD/R induced PC12 cells and MCAO/R injured rats' brain. The level of miR-32-5p was significantly reduced after OGD/R. Overexpression of miR-32-5p significantly reduced MCAO/R-induced brain damages in rats. Moreover, PTEN was found to be a target of miR-32-5p, and overexpression of PTEN attenuated the effects of miR-32-5p overexpression on cerebral I/R injuries. In addition, miR-32-5p was able to activate PI3K/AKT signaling by inhibiting PTEN. In conclusion, miR-32-5p prevents brain I/R injuries through modulating PTEN/PI3K/AKT signaling pathway.

The pivotal role of the NLRC4 inflammasome in neuroinflammation after intracerebral hemorrhage in rats

The NLRC4 inflammasome, a member of the nucleotide-binding and oligomerization domain-like receptor (NLR) family, amplifies inflammation by facilitating the processing of caspase-1, interleukin (IL)-1β, and IL-18. We explored whether NLRC4 knockdown alleviated inflammatory injury following intracerebral hemorrhage (ICH). Furthermore, we investigated whether NLRC4 inflammasome activation can be adjusted by the regulator of G protein signaling 2/leucine-rich repeat kinase-2 pathway. Fifty microliters of arterial blood was drawn and injected into the basal ganglion to simulate the ICH model. NLRC4 small interfering RNAs (siRNAs) were utilized to knockdown NLRC4. An LRRK2 inhibitor (GNE7915) was injected into the abdominal cavity. Short hairpin (sh) RNA lentiviruses and lentiviruses containing RGS2 were designed and applied to knockdown and promote RGS2 expression. Neurological functions, brain edema, Western blot, enzyme-linked immunosorbent, hematoxylin and eosin staining, Nissl staining, immunoprecipitation, immunofluorescence assay and Evans blue dye extravasation and autofluorescence assay were evaluated. It was shown that the NLRC4 inflammasome was activated following ICH injury. NLRC4 knockdown extenuated neuronal death, damage to the blood-brain barrier, brain edema and neurological deficiency 3 days after ICH. NLRC4 knockdown reduced myeloperoxidase (MPO) cells as well as tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β and IL-18 following ICH. GNE7915 reduced pNLRC4 and NLRC4 inflammasome activation. RGS2 suppressed the interaction of LRRK2 and NLRC4 and NLRC4 inflammasome activation by regulating pLRRK2. Our study demonstrated that the NLRC4 inflammasome may aggravate the inflammatory injury induced by ICH and that RGS2/LRRK2 may relieve inflammatory injury by restraining NLRC4 inflammasome activation.