Mitochondrial dysfunction associated with autophagy and mitophagy in cerebrospinal fluid cells of patients with delayed cerebral ischemia following subarachnoid hemorrhage

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.

Target Gene-Based Association Study of High Mobility Group Box Protein 1 in Intracranial Aneurysms in Koreans

Objective: We investigated the effect of high mobility group box 1 (HMGB1) on intracranial aneurysms (IAs) by analyzing single-nucleotide polymorphisms (SNPs) based on genome-wide association study (GWAS) data. HMGB1 mRNA and protein expression levels in plasma were also analyzed. Methods: This study was a comprehensive analysis of a GWAS dataset, including 250 patients with IAs and 294 controls. The HMGB1 gene region was targeted within SNP rs3742305 ± 10 kbp. Multivariate logistic regression analysis determined its association with IAs after adjusting for relevant clinical factors. HMGB1 mRNA expression was analyzed in the plasma of 24 patients selected from the GWAS dataset. The HMGB1 protein was analyzed by Western blotting. Results: A total of seven polymorphisms, including rs1360485, rs185382445, rs2039338, rs1045411, rs3742305, rs2249825, and rs189034241, were observed. Two SNPs, including rs1045411 (UTR-3) and rs3742305 (intron), showed strong linkage disequilibrium (r2 = 0.99). However, none of the seven SNPs associated with IAs had an adjusted p-value of < 0.0016 on multiple comparison analysis. HMGB1 mRNA levels (2-ΔCt) did not differ significantly between patients with IAs and the control subjects [1.07 (1.00-1.15) in patients with IAs vs. 1.05 (0.94-1.12) in controls; p = 0.67)]. Also, no significant difference in the degree of plasma HMGB1 protein expression was seen between the two groups (p = 0.82). Conclusions: The number of SNPs associated with HMGB1 and the degree of HMGB1 mRNA and protein expression were not significantly different between patients diagnosed with IAs and the controls.

Therapeutic Effect of Donepezil on Neuroinflammation and Cognitive Impairment after Moderate Traumatic Brain Injury

BACKGROUND

Despite the important clinical issue of cognitive impairment after moderate traumatic brain injury (TBI), there is currently no suitable treatment. Here, we used in vitro and in vivo models to investigate the effect of Donepezil-an acetylcholinesterase (AChE) inhibitor-on cognitive impairment in the acute period following injury, while focusing on neuroinflammation and autophagy- and mitophagy-related markers.

METHODS

The purpose of the in vitro study was to investigate potential neuroprotective effects in TBI-induced cells after donepezil treatment, and the in vivo study, the purpose was to investigate therapeutic effects on cognitive impairment in the acute period after injury by analyzing neuroinflammation and autophagy- and mitophagy-related markers. The in vitro TBI model involved injuring SH-SY5Y cells using a cell-injury controller and then investigating the effect of donepezil at a concentration of 80 μM. The in vivo TBI model was made using a stereotaxic impactor for male C57BL/6J mice. Immuno-histochemical markers and cognitive functions were compared after 7 days of donepezil treatment (1 mg/kg/day). Mice were divided into four groups: sham operation with saline treatment, sham operation with donepezil treatment, TBI with saline treatment, and TBI with donepezil treatment (18 mice in each group). Donepezil treatment was administered within 4 h post-TBI.

RESULTS

In vitro, donepezil was found to lead to increased cell viability and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1), along with decreased reactive oxygen species (ROS), lactate-dehydrogenase (LDH), 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA)-positive cells, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. The mRNA and protein expressions of neuroinflammation (Cyclooxygenase-2, COX-2; NOD-like receptor protein 3, NLRP3; Caspase-1; and Interleukin-1 beta, IL-1β), as well as autophagy- and mitophagy-related markers (death-associated protein kinase 1, DAPK1; PTEN-induced kinase 1, PINK1; BCL2/adenovirus E1B 19 kDa protein-interacting protein 3-like, BNIP3L; Beclin-1, BECN1; BCL2-associated X protein, BAX; microtubule-associated protein 1A/1B-light chain 3B (LC3B); Sequestosome-1; and p62) were all found to decrease after donepezil treatment. The in vivo study also showed that donepezil treatment resulted in decreased levels of cortical tissue losses and brain swelling in TBI compared to the TBI group without donepezil treatment. Donepezil treatment was also shown to decrease the mRNA and Western blotting expressions of all markers, and especially COX-2 and BNIP3L, which showed the most significant decreases. Moreover, TBI mice showed an decreased escape latency, increased alteration rate, and improved preference index, altogether pointing to better cognitive performance after donepezil treatment.

CONCLUSIONS

Donepezil treatment may be beneficial in improving cognitive impairment in the early phase of moderate traumatic brain injury by ameliorating neuroinflammation, as well as autophagy and mitophagy.

Release of CD36-associated cell-free mitochondrial DNA and RNA as a hallmark of space environment response

A detailed understanding of how spaceflight affects human health is essential for long-term space exploration. Liquid biopsies allow for minimally-invasive multi-omics assessments that can resolve the molecular heterogeneity of internal tissues. Here, we report initial results from the JAXA Cell-Free Epigenome Study, a liquid biopsy study with six astronauts who resided on the International Space Station (ISS) for more than 120 days. Analysis of plasma cell-free RNA (cfRNA) collected before, during, and after spaceflight confirms previously reported mitochondrial dysregulation in space. Screening with 361 cell surface marker antibodies identifies a mitochondrial DNA-enriched fraction associated with the scavenger receptor CD36. RNA-sequencing of the CD36 fraction reveals tissue-enriched RNA species, suggesting the plasma mitochondrial components originated from various tissues. We compare our plasma cfRNA data to mouse plasma cfRNA data from a previous JAXA mission, which had used on-board artificial gravity, and discover a link between microgravity and the observed mitochondrial responses.

Mitochondrial dysfunction and quality control lie at the heart of subarachnoid hemorrhage

The dramatic increase in intracranial pressure after subarachnoid hemorrhage leads to a decrease in cerebral perfusion pressure and a reduction in cerebral blood flow. Mitochondria are directly affected by direct factors such as ischemia, hypoxia, excitotoxicity, and toxicity of free hemoglobin and its degradation products, which trigger mitochondrial dysfunction. Dysfunctional mitochondria release large amounts of reactive oxygen species, inflammatory mediators, and apoptotic proteins that activate apoptotic pathways, further damaging cells. In response to this array of damage, cells have adopted multiple mitochondrial quality control mechanisms through evolution, including mitochondrial protein quality control, mitochondrial dynamics, mitophagy, mitochondrial biogenesis, and intercellular mitochondrial transfer, to maintain mitochondrial homeostasis under pathological conditions. Specific interventions targeting mitochondrial quality control mechanisms have emerged as promising therapeutic strategies for subarachnoid hemorrhage. This review provides an overview of recent research advances in mitochondrial pathophysiological processes after subarachnoid hemorrhage, particularly mitochondrial quality control mechanisms. It also presents potential therapeutic strategies to target mitochondrial quality control in subarachnoid hemorrhage.

Advances in biomarkers for vasospasm - Towards a future blood-based diagnostic test

Objective

Cerebral vasospasm and the resultant delayed cerebral infarction is a significant source of mortality following aneurysmal SAH. Vasospasm is currently detected using invasive or expensive imaging at regular intervals in patients following SAH, thus posing a risk of complications following the procedure and financial burden on these patients. Currently, there is no blood-based test to detect vasospasm.

Methods

PubMed, Web of Science, and Embase databases were systematically searched to retrieve studies related to cerebral vasospasm, aneurysm rupture, and biomarkers. The study search dated from 1997 to 2022. Data from eligible studies was extracted and then summarized.

Results

Out of the 632 citations screened, only 217 abstracts were selected for further review. Out of those, only 59 full text articles met eligibility and another 13 were excluded.

Conclusions

We summarize the current literature on the mechanism of cerebral vasospasm and delayed cerebral ischemia, specifically studies relating to inflammation, and provide a rationale and commentary on a hypothetical future bloodbased test to detect vasospasm. Efforts should be focused on clinical-translational approaches to create such a test to improve treatment timing and prediction of vasospasm to reduce the incidence of delayed cerebral infarction.

Epigenetic Reprogramming of Autophagy Drives Mutant IDH1 Glioma Progression and Response to Radiation

Mutant isocitrate dehydrogenase 1 (mIDH1; IDH1 R132H ) exhibits a gain of function mutation enabling 2-hydroxyglutarate (2HG) production. 2HG inhibits DNA and histone demethylases, inducing epigenetic reprogramming and corresponding changes to the transcriptome. We previously demonstrated 2HG-mediated epigenetic reprogramming enhances DNA-damage response and confers radioresistance in mIDH1 gliomas harboring p53 and ATRX loss of function mutations. In this study, RNA-seq and ChIP-seq data revealed human and mouse mIDH1 glioma neurospheres have downregulated gene ontologies related to mitochondrial metabolism and upregulated autophagy. Further analysis revealed that the decreased mitochondrial metabolism was paralleled by a decrease in glycolysis, rendering autophagy as a source of energy in mIDH1 glioma cells. Analysis of autophagy pathways showed that mIDH1 glioma cells exhibited increased expression of pULK1-S555 and enhanced LC3 I/II conversion, indicating augmented autophagy activity. This dependence is reflected by increased sensitivity of mIDH1 glioma cells to autophagy inhibition. Blocking autophagy selectively impairs the growth of cultured mIDH1 glioma cells but not wild-type IDH1 (wtIDH1) glioma cells. Targeting autophagy by systemic administration of synthetic protein nanoparticles packaged with siRNA targeting Atg7 (SPNP-siRNA-Atg7) sensitized mIDH1 glioma cells to radiation-induced cell death, resulting in tumor regression, long-term survival, and immunological memory, when used in combination with IR. Our results indicate autophagy as a critical pathway for survival and maintenance of mIDH1 glioma cells, a strategy that has significant potential for future clinical translation.

One Sentence Summary

The inhibition of autophagy sensitizes mIDH1 glioma cells to radiation, thus creating a promising therapeutic strategy for mIDH1 glioma patients.

Graphical abstract

Our genetically engineered mIDH1 mouse glioma model harbors IDH1 R132H in the context of ATRX and TP53 knockdown. The production of 2-HG elicited an epigenetic reprogramming associated with a disruption in mitochondrial activity and an enhancement of autophagy in mIDH1 glioma cells. Autophagy is a mechanism involved in cell homeostasis related with cell survival under energetic stress and DNA damage protection. Autophagy has been associated with radio resistance. The inhibition of autophagy thus radio sensitizes mIDH1 glioma cells and enhances survival of mIDH1 glioma-bearing mice, representing a novel therapeutic target for this glioma subtype with potential applicability in combined clinical strategies.

Identification of mitophagy and ferroptosis-related hub genes associated with intracerebral haemorrhage through bioinformatics analysis

BACKGROUND

Mitophagy and ferroptosis occur in intracerebral haemorrhage (ICH) but our understanding of mitophagy and ferroptosis-related genes remains incomplete.

AIM

This study aims to identify shared ICH genes for both processes.

METHODS

ICH differentially expressed mitophagy and ferroptosis-related genes (DEMFRGs) were sourced from the GEO database and literature. Enrichment analysis elucidated functions. Hub genes were selected via STRING, MCODE, and MCC algorithms in Cytoscape. miRNAs targeting hubs were predicted using miRWalk 3.0, forming a miRNA-hub gene network. Immune microenvironment variances were assessed with MCP and TIMER. Potential small molecules for ICH were forecasted via CMap database.

RESULTS

64 DEMFRGs and ten hub genes potentially involved in various processes like ferroptosis, TNF signalling pathway, MAPK signalling pathway, and NF-kappa B signalling pathway were discovered. Several miRNAs were identified as shared targets of hub genes. The ICH group showed increased infiltration of monocytic lineage and myeloid dendritic cells compared to the Healthy group. Ten potential small molecule drugs (e.g. Zebularine, TWS-119, CG-930) were predicted via CMap.

CONCLUSION

Several shared genes between mitophagy and ferroptosis potentially drive ICH progression via TNF, MAPK, and NF-kappa B pathways. These results offer valuable insights for further exploring the connection between mitophagy, ferroptosis, and ICH.

Clinical Impact and Mechanisms of Nonatherosclerotic Vascular Aging: The New Kid to Be Blocked

Ischemic cardiovascular disease and stroke remain the leading cause of global morbidity and mortality. During aging, protective mechanisms in the body gradually deteriorate, resulting in functional, structural, and morphologic changes that affect the vascular system. Because atherosclerotic plaques are not always present along with these alterations, we refer to this kind of vascular aging as nonatherosclerotic vascular aging (NAVA). To maintain proper vascular function during NAVA, it is important to preserve intracellular signalling, prevent inflammation, and block the development of senescent cells. Pharmacologic interventions targeting these components are potential therapeutic approaches for NAVA, with a particular emphasis on inflammation and senescence. This review provides an overview of the pathophysiology of vascular aging and explores potential pharmacotherapies that can improve the function of aged vasculature, focusing on NAVA.

Bioplastic (poly-3-hydroxybutyrate)-producing Massilia endophytica sp. nov., isolated from Cannabis sativa L. 'Cheungsam'

A rod-shaped, motile, Gram-negative bacterial strain named DM-R-R2A-13T was isolated from the plant Cannabis sativa L. 'Cheungsam'. The phylogenetic analysis of the 16S rRNA gene sequence revealed that strain DM-R-R2A-13T belongs to the family Oxalobacteraceae and is closely related to members of the genus Massilia, with Massilia flava (97.58% sequence similarity) and Massilia armeniaca (97.37% sequence similarity) being the closest members. The digital DNA-DNA hybridization (dDDH) values between strain DM-R-R2A-13T and Massilia flava CGMCC 1.10685T and Massilia armeniaca ZMN-3Twere 22.2% and 23.3%, while the average nucleotide identity (ANI) values were 78.85% and 79.63%, respectively. The DNA G+C content was measured to be 64.6 mol%. Moreover, the bacterium was found to contain polyhydroxyalkanoate (PHA) granules based on transmission electron microscopy, indicating its potential to produce bioplastic. Genome annotation revealed the presence of PHA synthase genes (phaC, phaR, phaP, and phaZ), and the biopolymer was identified as poly-3-hydroxybutyrate (PHB) based on nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) analyses. Using maltose as a carbon source, the strain produced PHB of up to 58.06% of its dry cell weight. Based on the phenotypic, chemotaxonomic, and phylogenetic characteristics, it has been determined that DM-R-R2A-13T represents a novel species belonging to the genus Massilia. As such, the name Massilia endophytica sp. nov. is proposed for this newly identified species. The type strain is DM-R-R2A-13T (= KCTC 92072T = GDMCC 1.2920T).

Escin enhanced the efficacy of sorafenib by autophagy-mediated apoptosis in lung cancer cells

Combining anti-cancer drugs has been exploited as promising treatment strategy to target lung cancer. Synergistic chemotherapies increase anti-cancer effect and reduce effective drug doses and side effects. In this study, therapeutic potential of escin in combination with sorafenib has been explored. 3-(4,5-Dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide assay was used to calculate IC50 values. The synergy was evaluated using Chou-Talaly algorithm. Cellular reactive oxygen species, mitochondrial membrane potential, annexin V, and cell-cycle studies were done by flow-cytometer, and autophagy biomarkers expression were determined using western blotting. Moreover, autophagy was knocked down using ATG5 siRNA to confirm its role, diethylnitrosamine-induced lung cancer model was used to check the synergy of sorafenib/escin. Escin significantly reduced the IC50 of sorafenib in A549 and NCIH460 cells. The combination of sorafenib/escin produced a 2.95 and 5.45 dose reduction index for sorafenib in A549 and NCI-H460 cells. The combination of over-expressed p62 and LC3-II reflects autophagy block-mediated late apoptosis. This phenomenon was reconfirmed by ATG5 knockdown. This combination also selectively targeted G0/G1 phase of cancer cells. In in vivo study, the combination reduced tumour load and lower elevated serum biochemical parameters. The combination of sorafenib/escin synergistically inhibits autophagy to induce late apoptosis in lung cancer cells' G0/G1 phase.

Autophagy and mitophagy-related extracellular mitochondrial dysfunction of cerebrospinal fluid cells in patients with hemorrhagic moyamoya disease

We aimed to investigate whether mitochondrial dysfunction in extracellular cerebrospinal fluid (CSF), which is associated with autophagy and mitophagy, might be involved in neurological outcomes in adult patients with hemorrhagic moyamoya disease (MMD) whose pathogenesis related to poor outcomes is not well-known. CSF samples were collected from 43 adult MMD patients and analyzed according to outcomes at 3 months. Fluorescence-activated cell sorter analysis (FACS) and the JC-1 red/green ratio were used to assess mitochondrial cells and intact mitochondrial membrane potential (MMP). We performed quantitative real-time polymerase chain reaction and Western blotting analyses of autophagy and mitophagy-related markers, including HIF1α, ATG5, pBECN1, BECN1, BAX, BNIP3L, DAPK1, and PINK1. Finally, FACS analysis with specific fluorescence-conjugated antibodies was performed to evaluate the potential cellular origin of CSF mitochondrial cells. Twenty-seven females (62.8%) with a mean age of 47.4 ± 9.7 years were included in the study. Among 43 patients with hemorrhagic MMD, 23 (53.5%) had poor outcomes. The difference in MMP was evident between the two groups (2.4 ± 0.2 in patients with poor outcome vs. 3.5 ± 0.4 in patients with good outcome; p = 0.02). A significantly higher expression (2-ΔCt) of HIF1α, ATG5, DAPK1 followed by BAX and BNIP3L mRNA and protein was also observed in poor-outcome patients compared to those with good outcomes. Higher percentage of vWF-positive mitochondria, suggesting endothelial cell origins, was observed in patients with good outcome compared with those with poor outcome (25.0 ± 1.4% in patients with good outcome vs. 17.5 ± 1.5% in those with poor outcome; p < 0.01). We observed the association between increased mitochondrial dysfunction concomitant with autophagy and mitophagy in CSF cells and neurological outcomes in adult patients with hemorrhagic MMD. Further prospective multicenter studies are needed to determine whether it has a diagnostic value for risk prediction.

Mitochondrial dysfunction and chromatin changes with autophagy-mediated survival in doxorubicin resistant cancer cell lines

Acquired chemoresistance against doxorubicin remains an obstacle in long-term treatment. The comprehensive molecular mechanism underlying the acquirement of doxorubicin resistance has not been reported. The objective of the present study is to understand the survival strategies and investigate alternate treatments for doxorubicin-resistant cervical and liver cancer cells. In this study, doxorubicin-resistant sublines were established by continuous incremental exposure of the drug to parental cervical and liver cancer cells. The transcriptome data in drug-resistant model revealed downregulated energy production pathways like glycolysis, oxidative phosphorylation, and mTOR signalling. This resulted in slow proliferation and altered mitochondrial changes in doxorubicin-resistant cells. The altered metabolic state of the resistant cells was associated with hypo-acetylation of chromatin. Pre-treatment with HDACi sensitized the drug-resistant cells to doxorubicin by increased drug accumulation in the cells, thereby leading to apoptosis. Additionally, we demonstrated that autophagy gets activated in doxorubicin-resistant cervical and liver cancer cells. Autophagy acts as pro-survival mechanism in resistant cells, as inhibition of autophagy leads to cell death. In conclusion, the data highlights survival ability of resistant cells with mitochondrial dysfunction, altered chromatin state, and pro-survival autophagy. The study proposes targeting chromatin alteration with the combinatorial treatment of HDACi with doxorubicin or survival mechanism through autophagy inhibitor against doxorubicin-resistant cancer phenotype.

Mitochondrial Dysfunction, Mitophagy and Their Correlation with Perinatal Complications: Preeclampsia and Low Birth Weight

Mitochondria are essential organelles and crucial for cellular survival. Mitochondrial biogenesis and mitophagy are dynamic features that are essential for both maintaining the health of the mitochondrial network and cellular demands. The accumulation of damaged mitochondria has been shown to be related to a wide range of pathologies ranging from neurological to musculoskeletal. Mitophagy is the selective autophagy of mitochondria, eliminating dysfunctional mitochondria in cells by engulfment within double-membraned vesicles. Preeclampsia and low birth weight constitute prenatal complications during pregnancy and are leading causes of maternal and fetal mortality and morbidity. Both placental implantation and fetal growth require a large amount of energy, and a defect in the mitochondrial quality control mechanism may be responsible for the pathophysiology of these diseases. In this review, we compiled current studies investigating the role of BNIP3, DRAM1, and FUNDC1, mediators of receptor-mediated mitophagy, in the progression of preeclampsia and the role of mitophagy pathways in the pathophysiology of low birth weight. Recent studies have indicated that mitochondrial dysfunction and accumulation of reactive oxygen species are related to preeclampsia and low birth weight. However, due to the lack of studies in this field, the results are controversial. Therefore, mitophagy-related pathways associated with these pathologies still need to be elucidated. Mitophagy-related pathways are among the promising study targets that can reveal the pathophysiology behind preeclampsia and low birth weight.

Sci-Seq of Human Fetal Salivary Tissue Introduces Human Transcriptional Paradigms and a Novel Cell Population

Multiple pathologies and non-pathological factors can disrupt the function of the non-regenerative human salivary gland including cancer and cancer therapeutics, autoimmune diseases, infections, pharmaceutical side effects, and traumatic injury. Despite the wide range of pathologies, no therapeutic or regenerative approaches exist to address salivary gland loss, likely due to significant gaps in our understanding of salivary gland development. Moreover, identifying the tissue of origin when diagnosing salivary carcinomas requires an understanding of human fetal development. Using computational tools, we identify developmental branchpoints, a novel stem cell-like population, and key signaling pathways in the human developing salivary glands by analyzing our human fetal single-cell sequencing data. Trajectory and transcriptional analysis suggest that the earliest progenitors yield excretory duct and myoepithelial cells and a transitional population that will yield later ductal cell types. Importantly, this single-cell analysis revealed a previously undescribed population of stem cell-like cells that are derived from SD and expresses high levels of genes associated with stem cell-like function. We have observed these rare cells, not in a single niche location but dispersed within the developing duct at later developmental stages. Our studies introduce new human-specific developmental paradigms for the salivary gland and lay the groundwork for the development of translational human therapeutics.

The Role of Circadian Clock Genes in Critical Illness: The Potential Role of Translational Clock Gene Therapies for Targeting Inflammation, Mitochondrial Function, and Muscle Mass in Intensive Care

The Earth's 24-h planetary rotation, with predictable light and heat cycles, has driven profound evolutionary adaptation, with prominent impacts on physiological mechanisms important for surviving critical illness. Pathways of interest include inflammation, mitochondrial function, energy metabolism, hypoxic signaling, apoptosis, and defenses against reactive oxygen species. Regulation of these by the cellular circadian clock (BMAL-1 and its network) has an important influence on pulmonary inflammation; ventilator-associated lung injury; septic shock; brain injury, including vasospasm; and overall mortality in both animals and humans. Whether it is cytokines, the inflammasome, or mitochondrial biogenesis, circadian medicine represents exciting opportunities for translational therapy in intensive care, which is currently lacking. Circadian medicine also represents a link to metabolic determinants of outcome, such as diabetes and cardiovascular disease. More than ever, we are appreciating the problem of circadian desynchrony in intensive care. This review explores the rationale and evidence for the importance of the circadian clock in surviving critical illness.

Exploration on the Mechanism of Ubiquitin Proteasome System in Cerebral Stroke

Stroke’s secondary damage, such as inflammation, oxidative stress, and mitochondrial dysfunction, are thought to be crucial factors in the disease’s progression. Despite the fact that there are numerous treatments for secondary damage following stroke, such as antiplatelet therapy, anticoagulant therapy, surgery, and so on, the results are disappointing and the side effects are numerous. It is critical to develop novel and effective strategies for improving patient prognosis. The ubiquitin proteasome system (UPS) is the hub for the processing and metabolism of a wide range of functional regulatory proteins in cells. It is critical for the maintenance of cell homeostasis. With the advancement of UPS research in recent years, it has been discovered that UPS is engaged in a variety of physiological and pathological processes in the human body. UPS is expected to play a role in the onset and progression of stroke via multiple targets and pathways. This paper explores the method by which UPS participates in the linked pathogenic process following stroke, in order to give a theoretical foundation for further research into UPS and stroke treatment.

Toll-Like Receptor 2 Modulates Pulmonary Inflammation and TNF-α Release Mediated by Mycoplasma pneumoniae

Objectives

To investigate the roles that Toll-like receptors (TLRs) play in lung inflammation mediated by Mycoplasma pneumoniae (MP).

Methods

The changes in TLRs and tumor necrosis factor alpha (TNF-α) in peripheral blood of children with M. pneumoniae pneumonia (MPP) were monitored, and the interactions of signaling molecules regulating TNF-α release in A549 cells and neutrophils after M. pneumoniae stimulation were investigated. In TLR2 knockout (TLR2-/-) mice, the levels of TNF-α in bronchial alveolar lavage fluid (BALF) and peripheral blood after mycoplasma infection and the pathological changes in the lung tissue of mice were detected.

Results

TNF-α levels in peripheral blood of children with MPP were higher than those in non-infected children, and children with refractory MPP had the highest levels of TNF-α and TLR2. TNF-α secretion and TLR2, myeloid differentiation primary response 88 (MyD88) and phospho-p65(p-p65) levels were increased in stimulated cells. TNF-α secretion was suppressed upon siRNA-mediated TLR2 silencing. Pharmacological inhibition of nuclear factor-kappa B (NF-κB) and MyD88 effectively reduced TNF-α expression. Compared with wild-type mice, the TNF-α in serum and BALF decreased, and lung pro-inflammatory response was partially suppressed in TLR2-/- mice.

Conclusion

We concluded that TLR2 regulates M. pneumoniae-mediated lung inflammation and TNF-α release through the TLR2-MyD88-NF-κB signaling pathway.

ACEA Attenuates Oxidative Stress by Promoting Mitophagy via CB1R/Nrf1/PINK1 Pathway after Subarachnoid Hemorrhage in Rats

Method

Endovascular perforation was performed to establish a SAH model of rats. ACEA was administered intraperitoneally 1 h after SAH. The CB1R antagonist AM251 was injected intraperitoneally 1 h before SAH induction. Adenoassociated virus- (AAV-) Nrf1 shRNA was infused into the lateral ventricle 3 weeks before SAH induction. Neurological tests, immunofluorescence, DHE, TUNEL, Nissl staining, transmission electron microscopy (TEM), and Western blot were performed.

Results

The expression of CB1R, Nrf1, PINK1, Parkin, and LC3II increased and peaked at 24 h after SAH. ACEA treatment exhibited the antioxidative stress and antiapoptosis effects after SAH. In addition, ACEA treatment increased the expression of Nrf1, PINK1, Parkin, LC3II, and Bcl-xl but repressed the expression of Romo-1, Bax, and cleaved caspase-3. Moreover, the TEM results demonstrated that ACEA promoted the formation of mitophagosome and maintained the normal mitochondrial morphology of neurons. The protective effect of ACEA was reversed by AM251 and Nrf1 shRNA, respectively.

Conclusions

This study demonstrated that ACEA alleviated oxidative stress and neurological dysfunction by promoting mitophagy after SAH, at least in part via the CB1R/Nrf1/PINK1 signaling pathway.

Mitochondrial Quality Control: A Pathophysiological Mechanism and Therapeutic Target for Stroke

Stroke is a devastating disease with high mortality and disability rates. Previous research has established that mitochondria, as major regulators, are both influenced by stroke, and further regulated the development of poststroke injury. Mitochondria are involved in several biological processes such as energy generation, calcium homeostasis, immune response, apoptosis regulation, and reactive oxygen species (ROS) generation. Meanwhile, mitochondria can evolve into various quality control systems, including mitochondrial dynamics (fission and fusion) and mitophagy, to maintain the homeostasis of the mitochondrial network. Various activities of mitochondrial fission and fusion are associated with mitochondrial integrity and neurological injury after stroke. Additionally, proper mitophagy seems to be neuroprotective for its effect on eliminating the damaged mitochondria, while excessive mitophagy disturbs energy generation and mitochondria-associated signal pathways. The balance between mitochondrial dynamics and mitophagy is more crucial than the absolute level of each process. A neurovascular unit (NVU) is a multidimensional system by which cells release multiple mediators and regulate diverse signaling pathways across the whole neurovascular network in a way with a high dynamic interaction. The turbulence of mitochondrial quality control (MQC) could lead to NVU dysfunctions, including neuron death, neuroglial activation, blood–brain barrier (BBB) disruption, and neuroinflammation. However, the exact changes and effects of MQC on the NVU after stroke have yet to be fully illustrated. In this review, we will discuss the updated mechanisms of MQC and the pathophysiology of mitochondrial dynamics and mitophagy after stroke. We highlight the regulation of MQC as a potential therapeutic target for both ischemic and hemorrhagic stroke.

Bioinformatics Analysis of Autophagy and Mitophagy Markers Associated with Delayed Cerebral Ischemia Following Subarachnoid Hemorrhage

Objective

To evaluate the interactions among differentially expressed autophagy and mitophagy markers in subarachnoid hemorrhage (SAH) patients with delayed cerebral ischemia (DCI).

Methods

The expression data of autophagy and mitophagy-related makers in the cerebrospinal fluid (CSF) cells was analyzed by real-time reverse transcription-polymerase chain reaction and Western blotting. The markers included death-associated protein kinase (DAPK)-1, BCL2 interacting protein 3 like (BNIP3L), Bcl-1 antagonist X, PINK, Unc-51 like autophagy activating kinase 1, nuclear dot protein 52, and p62. In silico functional analyses including gene ontology enrichment and the protein-protein interaction network were performed.

Results

A total of 56 SAH patients were included and 22 (38.6%) of them experienced DCI. The DCI patients had significantly increased mRNA levels of DAPK1, BNIP3L, and PINK1, and increased expression of BECN1 compared to the non-DCI patients. The most enriched biological process was the positive regulation of autophagy, followed by the response to mitochondrial depolarization. The molecular functions ubiquitin-like protein ligase binding and ubiquitin-protein ligase binding were enriched. In the cluster of cellular components, Lewy bodies and the phagophore assembly site were enriched. BECN1 was the most connected gene among the differentially expressed markers related to autophagy and mitophagy in the development of DCI.

Conclusion

Our study may provide novel insight into mitochondrial dysfunction in DCI pathogenesis.