Mitochondrial MPTP: A Novel Target of Ethnomedicine for Stroke Treatment by Apoptosis Inhibition

Exploring the intricacies of calcium dysregulation in ischemic stroke: Insights into neuronal cell death and therapeutic strategies

Calcium ion (Ca2+) dysregulation is one of the main causes of neuronal cell death and brain damage after cerebral ischemia. During ischemic stroke, the ability of neurons to maintain Ca2+ homeostasis is compromised. Ca2+ regulates various functions of the nervous system, including neuronal activity and adenosine triphosphate (ATP) production. Disruptions in Ca2+ homeostasis can trigger a cascade of events, including activation of the unfolded protein response (UPR) pathway, which is associated with endoplasmic reticulum (ER) stress and mitochondrial dysfunction. This response occurs when the cell is unable to manage protein folding within the ER due to various stressors, such as a high influx of Ca2+. Consequently, the UPR is initiated to restore ER function and alleviate stress, but prolonged activation can lead to mitochondrial dysfunction and, ultimately, cell death. Hence, precise regulation of Ca2+ within the cell is mandatory. The ER and mitochondria are two such organelles that maintain intracellular Ca2+ homeostasis through various calcium-operating channels, including ryanodine receptors (RyRs), inositol trisphosphate receptors (IP3Rs), sarco/endoplasmic reticulum calcium ATPases (SERCAs), the mitochondrial Na+/Ca2+ exchanger (NCLX), the mitochondrial calcium uniporter (MCU) and voltage-dependent anion channels (VDACs). These channels utilize Ca2+ sequestering and release mechanisms to maintain intracellular Ca2+ homeostasis and ensure proper cellular function and survival. The present review critically evaluates the significance of Ca2+ and its physiological role in cerebral ischemia. We have compiled recent findings on calcium's role and emerging treatment strategies, particularly targeting mitochondria and the endoplasmic reticulum, to address Ca2+ overload in cerebral ischemia.

Icariin improves oxidative stress injury during ischemic stroke via inhibiting mPTP opening

BACKGROUND

Ischemic stroke presents a significant threat to human health due to its high disability rate and mortality. Currently, the clinical treatment drug, rt-PA, has a narrow therapeutic window and carries a high risk of bleeding. There is an urgent need to find new effective therapeutic drugs for ischemic stroke. Icariin (ICA), a key ingredient in the traditional Chinese medicine Epimedium, undergoes metabolism in vivo to produce Icaritin (ICT). While ICA has been reported to inhibit neuronal apoptosis after cerebral ischemia-reperfusion (I/R), yet its underlying mechanism remains unclear.

METHODS

PC-12 cells were treated with 200 µM H2O2 for 8 h to establish a vitro model of oxidative damage. After administration of ICT, cell viability was detected by Thiazolyl blue tetrazolium Bromide (MTT) assay, reactive oxygen species (ROS) and apoptosis level, mPTP status and mitochondrial membrane potential (MMP) were detected by flow cytometry and immunofluorescence. Apoptosis and mitochondrial permeability transition pore (mPTP) related proteins were assessed by Western blotting. Middle cerebral artery occlusion (MCAO) model was used to establish I/R injury in vivo. After the treatment of ICA, the neurological function was scored by ZeaLonga socres; the infarct volume was observed by 2,3,5-Triphenyltetrazolium chloride (TTC) staining; HE and Nissl staining were used to detect the pathological state of the ischemic cortex; the expression changes of mPTP and apoptosis related proteins were detected by Western blotting.

RESULTS

In vitro: ICT effectively improved H2O2-induced oxidative injury through decreasing the ROS level, inhibiting mPTP opening and apoptosis. In addition, the protective effects of ICT were not enhanced when it was co-treated with mPTP inhibitor Cyclosporin A (CsA), but reversed when combined with mPTP activator Lonidamine (LND). In vivo: Rats after MCAO shown cortical infarct volume of 32-40%, severe neurological impairment, while mPTP opening and apoptosis were obviously increased. Those damage caused was improved by the administration of ICA and CsA.

CONCLUSIONS

ICA improves cerebral ischemia-reperfusion injury by inhibiting mPTP opening, making it a potential candidate drug for the treatment of ischemic stroke.

Rhodiola crenulata alleviates hypobaric hypoxia-induced brain injury by maintaining BBB integrity and balancing energy metabolism dysfunction

BACKGROUND/PURPOSE

Rhodiola crenulata (Hook. f. et Thoms.) H. Ohba (R. crenulate), a famous and characteristic Tibetan medicine, has been demonstrated to exert an outstanding brain protection role in the treatment of high-altitude hypoxia disease. However, the metabolic effects of R. crenulate on high-altitude hypoxic brain injury (HHBI) are still incompletely understood. Herein, the anti-hypoxic effect and associated mechanisms of R. crenulate were explored through both in vivo and in vitro experiments.

STUDY DESIGN/METHODS

The mice model of HHBI was established using an animal hypobaric and hypoxic chamber. R. crenulate extract (RCE, 0.5, 1.0 and 2.0 g/kg) and salidroside (Sal, 25, 50 and 100 mg/kg) was given by gavage for 7 days. Pathological changes and neuronal apoptosis of mice hippocampus and cortex were evaluated using H&E and TUNEL staining, respectively. The effects of RCE and Sal on the permeability of blood brain barrier (BBB) were detected by Evans blue staining and NIR-II fluorescence imaging. Meanwhile, the ultrastructural BBB and cerebrovascular damages were observed using a transmission electron microscope (TEM). The levels of tight junction proteins Claudin-1, ZO-1 and occludin were detected by immunofluorescence. Additionally, the metabolites in mice serum and brain were determined using UHPLC-MS and MALDI-MSI analysis. The cell viability of Sal on hypoxic HT22 cells induced by CoCl2 was investigated by cell counting kit-8. The contents of LDH, MDA, SOD, GSH-PX and SDH were detected by using commercial biochemical kits. Meanwhile, intracellular ROS, Ca2+ and mitochondrial membrane potential were determined by corresponding specific labeled probes. The intracellular metabolites of HT22 cells were performed by the targeted metabolomics analysis of the Q300 kit. The cell apoptosis and necrosis were examined by YO-PRO-1/PI, Annexin V/PI and TUNEL staining. In addition, mitochondrial morphology was tested by Mito-tracker red with confocal microscopy and TEM. Real-time ATP production, oxygen consumption rate, and proton efflux rate were measured using a Seahorse analyzer. Subsequently, MCU, OPA1, p-Drp1ser616, p-AMPKα, p-AMPKβ and Sirt1 were determined by immunofluorescent and western blot analyses.

RESULTS

The results demonstrated that R. crenulate and Sal exert anti-hypoxic brain protection from inhibiting neuronal apoptosis, maintaining BBB integrity, increasing tight junction protein Claudin-1, ZO-1 and occludin and improving mitochondrial morphology and function. Mechanistically, R. crenulate and Sal alleviated HHBI by enhancing the tricarboxylic acid cycle to meet the demand of energy of brain. Additionally, experiments in vitro confirmed that Sal could ameliorate the apoptosis of HT22 cells, improve mitochondrial morphology and energy metabolism by enhancing mitochondrial respiration and glycolysis. Meanwhile, Sal-mediated MCU inhibited the activation of Drp1 and enhanced the expression of OPA1 to maintain mitochondrial homeostasis, as well as activation of AMPK and Sirt1 to enhance ATP production.

CONCLUSION

Collectively, the findings suggested that RCE and Sal may afford a protective intervention in HHBI through maintaining BBB integrity and improving energy metabolism via balancing MCU-mediated mitochondrial homeostasis by activating the AMPK/Sirt1 signaling pathway.

Emodin Blocks mPTP Opening and Improves LPS-Induced HMEC-1 Cell Injury by Upregulation of ATP5A1

BACKGROUND

Emodin has been shown to exert anti-inflammatory and cytoprotective effects. Our study aimed to identify a novel anti-inflammatory mechanism of emodin.

METHODS

An LPS-induced model of microvascular endothelial cell (HMEC-1) injury was constructed. Cell proliferation was examined using a CCK-8 assay. The effects of emodin on reactive oxygen species (ROS), cell migration, the mitochondrial membrane potential (MMP), and the opening of the mitochondrial permeability transition pore (mPTP) were evaluated. Actin-Tracker Green was used to examine the relationship between cell microfilament reconstruction and ATP5A1 expression. The effects of emodin on the expression of ATP5A1, NALP3, and TNF-α were determined. After treatment with emodin, ATP5A1 and inflammatory factors (TNF-α, IL-1, IL-6, IL-13 and IL-18) were examined by Western blotting.

RESULTS

Emodin significantly increased HMEC-1 cell proliferation and migration, inhibited the production of ROS, increased the mitochondrial membrane potential, and blocked the opening of the mPTP. Moreover, emodin could increase ATP5A1 expression, ameliorate cell microfilament remodeling, and decrease the expression of inflammatory factors. In addition, when ATP5A1 was overexpressed, the regulatory effect of emodin on inflammatory factors was not significant.

CONCLUSION

Our findings suggest that emodin can protect HMEC-1 cells against inflammatory injury. This process is modulated by the expression of ATP5A1.

The protective mechanism of SIRT3 and potential therapy in acute kidney injury

Acute kidney injury (AKI) is a complex clinical syndrome with a poor short-term prognosis, which increases the risk of the development of chronic kidney diseases and end-stage kidney disease. However, the underlying mechanism of AKI remains to be fully elucidated, and effective prevention and therapeutic strategies are still lacking. Given the enormous energy requirements for filtration and absorption, the kidneys are rich in mitochondria, which are unsurprisingly involved in the onset or progression of AKI. Accumulating evidence has recently documented that Sirtuin 3 (SIRT3), one of the most prominent deacetylases highly expressed in the mitochondria, exerts a protective effect on AKI. SIRT3 protects against AKI by regulating energy metabolism, inhibiting oxidative stress, suppressing inflammation, ameliorating apoptosis, inhibiting early-stage fibrosis and maintaining mitochondrial homeostasis. Besides, a number of SIRT3 activators have exhibited renoprotective properties both in animal models and in vitro experiments, but have not yet been applied to clinical practice, indicating a promising therapeutic approach. In this review, we unravel and summarize the recent advances in SIRT3 research and the potential therapy of SIRT3 activators in AKI.

Eucommia ulmoides Leaves Alleviate Cognitive Dysfunction in Dextran Sulfate Sodium (DSS)-Induced Colitis Mice through Regulating JNK/TLR4 Signaling Pathway

Ulcerative colitis (UC) is one of the inflammatory bowel diseases (IBD) that is characterized by systemic immune system activation. This study was performed to assess the alleviative effect of administering an aqueous extract of Eucommia ulmoides leaves (AEEL) on cognitive dysfunction in mice with dextran sulfate sodium (DSS)-induced colitis. The major bioactive compounds of AEEL were identified as a quinic acid derivative, caffeic acid-O-hexoside, and 3-O-caffeoylquinic acid using UPLC Q-TOF/MSE. AEEL administration alleviated colitis symptoms, which are bodyweight change and colon shortening. Moreover, AEEL administration protected intestinal barrier integrity by increasing the tight junction protein expression levels in colon tissues. Likewise, AEEL improved behavioral dysfunction in the Y-maze, passive avoidance, and Morris water maze tests. Additionally, AEEL improved short-chain fatty acid (SCFA) content in the feces of DSS-induced mice. In addition, AEEL improved damaged cholinergic systems in brain tissue and damaged mitochondrial and antioxidant functions in colon and brain tissues caused by DSS. Also, AEEL protected against DSS-induced cytotoxicity and inflammation in colon and brain tissues by c-Jun N-terminal kinase (JNK) and the toll-like receptor 4 (TLR4) signaling pathway. Therefore, these results suggest that AEEL is a natural material that alleviates DSS-induced cognitive dysfunction with the modulation of gut-brain interaction.

Chuanzhitongluo Inhibits Neuronal Apoptosis in Mice with Acute Ischemic Stroke by Regulating the PI3K/AKT Signaling Pathway

BACKGROUND AND PURPOSE

Apoptosis is involved in the occurrence and development of acute ischemic stroke (AIS). This study aimed to assess whether Chuanzhitongluo (CZTL), a multi-target and multi-pathway compound preparation, plays a neuroprotective role in AIS by modulating neuronal apoptosis via the PI3K/AKT signaling pathway.

METHODS

A mouse model of AIS was established by photochemical processes. Cerebral infarction volume was measured by 2% staining with 2, 3, and 5-triphenyl tetrazole chloride (TTC). Neuron apoptosis was assessed by TUNEL staining. Apoptosis RNA arrays were used to detect changes in apoptosis-related gene expression profiles. Western blotting was used to detect proteins involved in the PI3K/AKT signaling pathway.

RESULTS

The study demonstrated that CZTL could potentially mitigate neuronal apoptosis in AIS mice. This appears to be achieved via the up-regulation of certain genes such as BCL-2, Birc6, and others, coupled with the down-regulation of genes like BAX, Bid, and Casp3. Further validation revealed that CZTL could enhance the expression of BCL-2 and reduce the expression of Cleaved Caspase-3 and BAX at both the gene and protein levels. The study also found that CZTL can enhance the phosphorylation level of the PI3K/AKT signaling pathway. In contrast to these findings, the PI3K inhibitor LY294002 notably amplified neuronal apoptosis in AIS mice.

CONCLUSIONS

These findings imply that CZTL's ability to inhibit neuronal apoptosis may be linked to the activation of AIS's PI3K/AKT signaling pathway.

The MT1 receptor as the target of ramelteon neuroprotection in ischemic stroke

Stroke is the leading cause of death and disability worldwide. Novel and effective therapies for ischemic stroke are urgently needed. Here, we report that melatonin receptor 1A (MT1) agonist ramelteon is a neuroprotective drug candidate as demonstrated by comprehensive experimental models of ischemic stroke, including a middle cerebral artery occlusion (MCAO) mouse model of cerebral ischemia in vivo, organotypic hippocampal slice cultures ex vivo, and cultured neurons in vitro; the neuroprotective effects of ramelteon are diminished in MT1-knockout (KO) mice and MT1-KO cultured neurons. For the first time, we report that the MT1 receptor is significantly depleted in the brain of MCAO mice, and ramelteon treatment significantly recovers the brain MT1 losses in MCAO mice, which is further explained by the Connectivity Map L1000 bioinformatic analysis that shows gene-expression signatures of MCAO mice are negatively connected to melatonin receptor agonist like Ramelteon. We demonstrate that ramelteon improves the cerebral blood flow signals in ischemic stroke that is potentially mediated, at least, partly by mechanisms of activating endothelial nitric oxide synthase. Our results also show that the neuroprotection of ramelteon counteracts reactive oxygen species-induced oxidative stress and activates the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Ramelteon inhibits the mitochondrial and autophagic death pathways in MCAO mice and cultured neurons, consistent with gene set enrichment analysis from a bioinformatics perspective angle. Our data suggest that Ramelteon is a potential neuroprotective drug candidate, and MT1 is the neuroprotective target for ischemic stroke, which provides new insights into stroke therapy. MT1-KO mice and cultured neurons may provide animal and cellular models of accelerated ischemic damage and neuronal cell death.

Mitochondrial-targeted and ROS-responsive nanocarrier via nose-to-brain pathway for ischemic stroke treatment

Oxidative stress injury and mitochondrial dysfunction are major obstacles to neurological functional recovery after ischemic stroke. The development of new approaches to simultaneously diminish oxidative stress and resist mitochondrial dysfunction is urgently needed. Inspired by the overproduced reactive oxygen species (ROS) at ischemic neuron mitochondria, multifunctional nanoparticles with ROS-responsiveness and mitochondrial-targeted (SPNPs) were engineered, achieving specific targeting delivery and controllable drug release at ischemic penumbra. Due to the nose-to-brain pathway, SPNPs which were encapsulated in a thermo-sensitive gel by intranasal administration were directly delivered to the ischemic penumbra bypassing the blood‒brain barrier (BBB) and enhancing delivery efficiency. The potential of SPNPs for ischemic stroke treatment was systematically evaluated in vitro and in rat models of middle cerebral artery occlusion (MCAO). Results demonstrated the mitochondrial-targeted and protective effects of SPNPs on H2O2-induced oxidative damage in SH-SY5Y cells. In vivo distribution analyzed by fluorescence imaging proved the rapid and enhanced active targeting of SPNPs to the ischemic area in MCAO rats. SPNPs by intranasal administration exhibited superior therapeutic efficacy by alleviating oxidative stress, diminishing inflammation, repairing mitochondrial function, and decreasing apoptosis. This strategy provided a multifunctional delivery system for the effective treatment of ischemic injury, which also implies a potential application prospect for other central nervous diseases.

Identification and Validation of Active Ingredient in Cerebrotein Hydrolysate-I Based on Pharmacokinetic and Pharmacodynamic Studies

Cerebrotein hydrolysate-1 (CH-1), a mixture of small peptides, polypeptides, and various amino acids derived from porcine brain, has been widely used in the treatment of cerebral injury. However, the bioactive composition and pharmacokinetics of CH-1 are still unexplored because of their complicated composition and relatively tiny amounts in vivo. Herein, NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly used to qualitatively analyze the components of CH-1. A total of 1347 peptides were identified, of which 43 peptides were characterized by high mass spectrometry (MS) intensity and identification accuracy. We then innovatively synthesized four main peptides for activity verification, and the results suggested that Pep72 (NYEPPTVVPGGDL) had the strongest neuroprotective effect on both in vivo and in vitro models. Next, a quantitative method for Pep72 was established based on liquid chromatography tandem mass spectrometry (LC-MS/MS) with the aid of Skyline software and then used in its pharmacokinetic studies. The results revealed that Pep72 had a high elimination rate and low exposure in rats. In addition, a hCMEC/D3-based in vitro model was built and firstly used to investigate the transport of Pep72. We found that Pep72 had extremely low blood-brain barrier permeability and was not a substrate of efflux transporters. The biotransformation of Pep72 in rat fresh plasma and tissues was investigated to explore the contradiction between pharmacokinetics and efficacy. A total of 11 main metabolites were structurally identified, with PGGDL and EPPTVPGGDL being the main metabolites of Pep72. Notably, metalloproteinase and cysteine protease were confirmed to be the main enzymes mediating Pep72 metabolism in rat tissues. SIGNIFICANCE STATEMENT: The NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly applied to discover the components of CH-1, and one main peptide Pep72 (NYEPPTVVPGGDL) was innovatively synthesized and firstly found to have the strongest neuroprotective effect among 1347 peptides identified from CH-1. Our study is the first time to identify and verify the active ingredient of CH-1 from the perspective of pharmacokinetics and pharmacodynamics, and provides a systematic technical platforms and strategies for the active substance research of other protein hydrolysates.

Regulated necrosis pathways: a potential target for ischemic stroke

Globally, ischemic stroke causes millions of deaths per year. The outcomes of ischemic stroke are largely determined by the amount of ischemia-related and reperfusion-related neuronal death in the infarct region. In the infarct region, cell injuries follow either the regulated pathway involving precise signaling cascades, such as apoptosis and autophagy, or the nonregulated pathway, which is uncontrolled by any molecularly defined effector mechanisms such as necrosis. However, numerous studies have recently found that a certain type of necrosis can be regulated and potentially modified by drugs and is nonapoptotic; this type of necrosis is referred to as regulated necrosis. Depending on the signaling pathway, various elements of regulated necrosis contribute to the development of ischemic stroke, such as necroptosis, pyroptosis, ferroptosis, pathanatos, mitochondrial permeability transition pore-mediated necrosis and oncosis. In this review, we aim to summarize the underlying molecular mechanisms of regulated necrosis in ischemic stroke and explore the crosstalk and interplay among the diverse types of regulated necrosis. We believe that targeting these regulated necrosis pathways both pharmacologically and genetically in ischemia-induced neuronal death and protection could be an efficient strategy to increase neuronal survival and regeneration in ischemic stroke.

Arsenic-Induced, Mitochondria-Mediated Apoptosis Is Associated with Decreased Peroxisome Proliferator-Activated Receptor γ Coactivator α in Rat Brains

Chronic exposure to arsenic in drinking water damages cognitive function, and nerve cell apoptosis is one of the primary characteristics. The damage to mitochondrial structure and/or function is one of the main characteristics of apoptosis. Peroxisome proliferator-activated receptor γ coactivator α (PGC-1α) is involved in the regulation of mitochondrial biogenesis, energy metabolism, and apoptosis. In this study, we aimed to study the role of PGC-1α in sodium arsenite (NaAsO₂)-induced mitochondrial apoptosis in rat hippocampal cells. We discovered that increased arsenic-induced apoptosis in rat hippocampus increased with NaAsO₂ (0, 2, 10, and 50 mg/L, orally via drinking water for 12 weeks) exposure by TUNEL assay, and the structure of mitochondria was incomplete and swollen and had increased lysosomes, lipofuscins, and nuclear membrane shrinkage observed via transmission electron microscopy. Furthermore, NaAsO₂ reduced the levels of Bcl-2 and PGC-1α and increased the levels of Bax and cytochrome C expression. Moreover, correlation analysis showed that brain arsenic content was negatively correlated with PGC-1α levels and brain ATP content; PGC-1α levels were negatively correlated with apoptosis rate; and brain ATP content was positively correlated with PGC-1α levels, but no significant correlation between ATP content and apoptosis has been observed in this study. Taken together, the results of this study indicate that NaAsO₂-induced mitochondrial pathway apoptosis is related to the reduction of PGC-1α, accompanied by ATP depletion.

Hyperglycemia Aggravates the Cerebral Ischemia Injury via Protein O-GlcNAcylation

BACKGROUND

At least one-third of Alzheimer's disease (AD) patients have cerebrovascular abnormalities, micro- and macro-infarctions, and ischemic white matter alterations. Stroke prognosis impacts AD development due to vascular disease. Hyperglycemia can readily produce vascular lesions and atherosclerosis, increasing the risk of cerebral ischemia. Our previous studies have proved that protein O-GlcNAcylation-a dynamic and reversible post-translational modification, protects against ischemic stroke. However, the role of O-GlcNAcylation in hyperglycemia aggravating cerebral ischemia injury remained unclear.

OBJECTIVE

In the present study, we investigated the role and mechanism of protein O-GlcNAcylation in hyperglycemia exacerbating cerebral ischemia injury.

METHODS

High glucose-cultured brain microvascular endothelial (bEnd3) cells were injured by oxygen-glucose deprivation. Cell viability was used as the assay result. Stroke outcomes and hemorrhagic transformation incidence were assessed in mice after middle cerebral artery occlusion under high glucose and streptozotocin-induced hyperglycemic conditions. Western blot estimated that O-GlcNAcylation influenced apoptosis levels in vitro and in vivo.

RESULTS

In in vitro analyses showed that Thiamet-G induces upregulation of protein O-GlcNAcylation, which attenuates oxygen-glucose deprivation/R-induce injury in bEnd3 cells cultured under normal glucose conditions, while aggravated it under high glucose conditions. In in vivo analyses, Thiamet-G exacerbated cerebral ischemic injury and induced hemorrhagic transformation, accompanied by increased apoptosis. While blocking protein O-GlcNAcylation with 6-diazo-5-oxo-L-norleucine alleviated cerebral injury of ischemic stroke in different hyperglycemic mice.

CONCLUSION

Overall, our study indicates a critical role for O-GlcNAcylation in that hyperglycemia aggravates cerebral ischemia injury. O-GlcNAcylation may be a potential therapeutic drug for ischemic stroke associated with AD.

Role of organellar Ca2+-activated K+ channels in disease development

The organellar Ca2+-activated K+ channels share a similar ability to transfer the alteration of Ca2+ concentration to membrane conductance of potassium. Multiple effects of Ca2+-activated K+ channels on cell metabolism and complex signaling pathways during organ development have been explored. The organellar Ca2+-activated K+ channels are able to control the ionic equilibrium and are always associated with oxidative stress in different organelles and the whole cells. Some drugs targeting Ca2+-activated K+ channels have been tested for various diseases in clinical trials. In this review, the known roles of organellar Ca2+-activated K+ channels were described, and their effects on different diseases, particularly on diabetes, cardiovascular diseases, and neurological diseases were discussed. It was attempted to summarize the currently known operational modes with the involvement of organellar Ca2+-activated K+ channels. This review may assist scholars to more comprehensively understand organellar Ca2+-activated K+ channels and related diseases.

Renoprotective effects of ferulic acid mediated by AMPKα1 against lipopolysaccharide-induced damage

The kidney is susceptible to lipopolysaccharide (LPS)-induced damage with sepsis, and renal dysfunction is a leading cause of mortality in patients with sepsis. However, the renoprotective effects of ferulic acid (FA) during sepsis and the underlying mechanism remain unclear. This study explored these renoprotective effects using NRK-52E cells and mice with LPS-induced renal damage. The results showed that after LPS challenge, NRK-52E cell viability decreased, whereas lactate dehydrogenase, caspase-3 activity, apoptosis, the release of the inflammatory cytokines, and reactive oxygen species generation increased. Further, the activities of endogenous enzymatic and non-enzymatic antioxidant systems, and energy metabolism were inhibited, mitochondrial membrane potential was lost, mitochondrial permeability transition pores opened, renal blood flow and excretory functions were reduced, and the morphology and ultrastructure of renal tissue were seriously damaged in mice exposed to LPS. FA pretreatment upregulated AMP-activated protein kinase (AMPK) α1 expression and phosphorylation and significantly reversed the aforementioned functional, enzymological, and morphological indexes in vivo and in vitro. However, these renoprotective effects of FA were attenuated by compound C, an AMPK inhibitor. In conclusion, FA pretreatment can upregulate AMPKα1 expression and phosphorylation, inhibit inflammatory cytokine release and oxidative stress, improve mitochondrial function and energy supply, alleviate apoptosis, and ultimately protect renal tissue against LPS damage.

Autophagy and Apoptosis in Acute Brain Injuries: From Mechanism to Treatment

Significance: Autophagy and apoptosis are two important cellular mechanisms behind brain injuries, which are severe clinical situations with increasing incidences worldwide. To search for more and better treatments for brain injuries, it is essential to deepen the understanding of autophagy, apoptosis, and their interactions in brain injuries. This article first analyzes how autophagy and apoptosis participate in the pathogenetic processes of brain injuries respectively and mutually, then summarizes some promising treatments targeting autophagy and apoptosis to show the potential clinical applications in personalized medicine and precision medicine in the future. Recent Advances: Most current studies suggest that apoptosis is detrimental to brain recovery. Several studies indicate that autophagy can cause unnecessary death of neurons after brain injuries, while others show that autophagy is beneficial for acute brain injuries (ABIs) by facilitating the removal of damaged proteins and organelles. Whether autophagy is beneficial or detrimental in ABIs depends on many factors, and the results from different research groups are diverse or even controversial, making this topic more appealing to be explored further. Critical Issues: Neuronal autophagy and apoptosis are two primary pathological processes in ABIs. How they interact with each other and how their regulations affect the outcome and prognosis of brain injuries remain uncertain, making these answers more critical. Future Directions: Insights into the interplay between autophagy and apoptosis and the accurate regulations of their balance in ABIs may promote personalized and precise treatments in the field of brain injuries. Antioxid. Redox Signal. 38, 234-257.

The Role of Mitochondria-Targeting miRNAs in Intracerebral Hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Arterial hypertension (AH) is most often the cause of ICH, followed by atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication and vitamin deficiencies. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. AH is difficult to treat, requires surgery and can lead to disability or death. One of the important directions in the study of the pathogenesis of ICH is mitochondrial dysfunction and its regulation. The key role of mitochondrial dysfunction in AH and atherosclerosis, as well as in the development of brain damage after hemorrhage, has been acknowledged. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that regulate a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., primarily through gene repression. There is growing evidence to support dysregulated miRNAs in various cardiovascular diseases, including ICH. Further, the realization of miRNAs within mitochondrial compartment has challenged the traditional knowledge of signaling pathways involved in the regulatory network of cardiovascular diseases. However, the role of miRNAs in mitochondrial dysfunction for ICH is still under-appreciated, with comparatively much lesser studies and investigations reported, than those in other cardiovascular diseases. In this review, we summarize the up-to-date findings on the published role miRNAs in mitochondrial function for ICH, and the potential use of miRNAs in clinical settings, such as potential therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

The Improvement of Functional State of Brain Mitochondria with Astaxanthin in Rats after Heart Failure

The relationship between neurological damage and cardiovascular disease is often observed. This type of damage is both a cause and an effect of cardiovascular disease. Mitochondria are the key organelles of the cell and are primarily subject to oxidative stress. Mitochondrial dysfunctions are involved in the etiology of various diseases. A decrease in the efficiency of the heart muscle can lead to impaired blood flow and decreased oxygen supply to the brain. Astaxanthin (AST), a marine-derived xanthophyll carotenoid, has multiple functions and its effects have been shown in both experimental and clinical studies. We investigated the effects of AST on the functional state of brain mitochondria in rats after heart failure. Isoproterenol (ISO) was used to cause heart failure. In the present study, we found that ISO impaired the functional state of rat brain mitochondria (RBM), while the administration of AST resulted in an improvement in mitochondrial efficiency. The respiratory control index (RCI) in RBM decreased with the use of ISO, while AST administration led to an increase in this parameter. Ca²⁺ retention capacity (CRC) decreased in RBM isolated from rat brain after ISO injection, and AST enhanced CRC in RBM after heart failure. The study of changes in the content of regulatory proteins such as adenine nucleotide translocase 1 and 2 (ANT1/2), voltage dependent anion channel (VDAC), and cyclophilin D (CyP-D) of mitochondrial permeability transition pore (mPTP) showed that ISO reduced their level, while AST restored the content of these proteins almost to the control value. In general, AST improves the functional state of mitochondria and can be considered as a prophylactic drug in various therapeutic approaches.

Downhill running induced DNA damage enhances mitochondrial membrane permeability by facilitating ER-mitochondria signaling

To observe whether downhill running can lead to DNA damage in skeletal muscle cells and changes in mitochondrial membrane permeability and to explore whether the DNA damage caused by downhill running can lead to changes in mitochondrial membrane permeability by regulating the components of the endoplasmic reticulum mitochondrial coupling structure (MAM). A total of 48 male adult Sprague-Dawley rats were randomly divided into a control group (C, n = 8) and a motor group (E, n = 40). Rats in Group E were further divided into 0 h (E0), 12 h (E12), 24 h (E24), 48 h (E48) and 72 h (E72) after prescribed exercise, with 8 rats in each group. At each time point, flounder muscle was collected under general anaesthesia. The DNA oxidative damage marker 8-hydroxydeoxyguanosine (8-OHdG) was detected by immunofluorescence. The expression levels of the DNA damage-related protein p53 in the nucleus and the EI24 protein and reep1 protein in whole cells were detected by Western blot. The colocalization coefficients of the endoplasmic reticulum protein EI24 and the mitochondrial protein Vdac2 were determined by immunofluorescence double staining, and the concentration of Ca²⁺ in skeletal muscle mitochondria was detected by a fluorescent probe. Finally, the opening of the mitochondrial membrane permeability transition pore (mPTP) was detected by immunofluorescence. Twelve hours after downhill running, the mitochondrial membrane permeability of the mPTP opened the most (P < 0.05), the content of 8-OHdG in skeletal muscle peaked (P < 0.05), and the levels of the regulatory protein p53, mitochondrial Ca²⁺, and the EI24 and reep1 proteins peaked (P < 0.01). Moreover, the colocalization coefficients of EI24 and Vdac2 and the Mandes coefficients of the two proteins increased first and then recovered 72 h after exercise (P < 0.05). (1) Downhill running can lead to DNA damage in skeletal muscle cells, overload of mitochondrial Ca²⁺ and large opening of membrane permeability transformation pores. (2) The DNA damage caused by downhill running may result in p53 promoting the transcriptional activation of reep1 and EI24, enhancing the interaction between EI24 and Vdac2, and then leading to an increase in Ca²⁺ in skeletal muscle mitochondria and the opening of membrane permeability transition pores.

Jian-Pi-Yi-Shen decoction inhibits mitochondria-dependent granulosa cell apoptosis in a rat model of POF

As a widely applied traditional Chinese medicine (TCM), Jian-Pi-Yi-Shen (JPYS) decoction maybe applied in curing premature ovarian failure (POF) besides chronic kidney disease (CKD). In vivo experiments, 40 female SD (8-week-old) rats were randomized into four groups, namely, control group (negative control), POF model group, JPYS treatment group, and triptorelin treatment group (positive control). JPYS group was treated with JPYS decoction (oral, 11 g/kg) for 60 days, and the triptorelin group was treated with triptorelin (injection, 1.5 mg/kg) for 10 days before the administration of cyclophosphamide (CTX) (50 mg/kg body weight) to establish POF model. We examined apoptosis, mitochondrial function, and target gene (ASK1/JNK pathway and mitochondrial fusion/fission) expression. In vitro experiments, the KGN human granulosa cell line was used. Cells were pretreated with CTX (20, 40, and 60 μg/mL) for 24 h, followed by JPYS-containing serum (2, 4, and 8 %) for 24 h. Thereafter, these cells were employed to assess apoptosis, mitochondrial function, and target gene levels of protein and mRNA. In vivo, JPYS alleviated injury and suppressed apoptosis in POF rats. In addition, JPYS improved ovarian function. JPYS inhibit apoptosis of granulosa cells through improving mitochondrial function by activating ASK1/JNK pathway. In vitro, JPYS inhibited KGN cell apoptosis through inhibited ASK1/JNK pathway and improved mitochondrial function. The effects of GS-49977 were similar to those of JPYS. During POF, mitochondrial dysfunction occurs in the ovary and leads to granulosa cell apoptosis. JPYS decoction improves mitochondrial function and alleviates apoptosis through ASK1/JNK pathway.

Exogenous 5-aminolevulinic acid alleviates low-temperature injury by regulating glutathione metabolism and β-alanine metabolism in tomato seedling roots

Food availability represents a major worldwide concern due to climate change and population growth. Low-temperature stress (LTS) severely restricts the growth of tomato seedlings. Exogenous 5-aminolevulinic acid (ALA) can alleviate the harm of abiotic stress including LTS; however, data on its protective mechanism on tomato seedling roots, the effects of organelle structure, and the regulation of metabolic pathways under LTS are lacking. In this study, we hope to fill the above gaps by exploring the effects of exogenous ALA on morphology, mitochondrial ultrastructure, reactive oxygen species (ROS) enrichment, physiological indicators, related gene expression, and metabolic pathway in tomato seedlings root under LTS. Results showed that ALA pretreatment could increase the activity of antioxidant enzymes and the content of antioxidant substances in tomato seedlings roots under LTS to scavenge the massively accumulated ROS, thereby protecting the mitochondrial structure of roots and promoting root development under LTS. Combined transcriptomic and metabolomic analysis showed that exogenous ALA pretreatment activated the glutathione metabolism and β-alanine metabolism of tomato seedling roots under LTS, further enhanced the scavenging ability of tomato seedling roots to ROS, and improved the low-temperature tolerance of tomato seedlings. The findings provide a new insight into the regulation of the low-temperature tolerance of tomato by exogenous ALA.

Study on complications of osteoporosis based on network pharmacology

Osteoporosis is a serious threat to human life. Guben Zenggu Granule is an empirical prescription for clinical treatment of osteoporosis. MC3T3-E1 cells are mouse osteogenic precursor cells with osteogenic differentiation, and are classic cells for studying bone metabolism and osteogenic mechanism, as well as mechanical stimulation sensitive cells. Therefore, it can be inferred that Guben Zenggu granule can repair MC3T3-E1 cells under continuous static pressure overload. This study aims to through the network of pharmacology and gene sequencing method, reveal thrift increase bone particles under the condition of continuous static pressure overload on osteogenesis mechanism of MC3T3-E1 cells. In the process of analysis, from a variety of 98 compounds was predicted in the database, a collection of 474 goals, a total of 29,164 difference between two groups of genes. Then, construction of composite targets between cells and predict targets and protein - protein interaction networks, and through the cluster analysis to further explore the relationship between the target. In addition, linkages between target proteins and cells were further identified using Gene Ontology (GO) and Pathways (KEGG Pathway). Finally, the repair effect of Guben Zenggu granule on MC3T3-E1 cells under continuous static pressure overload was verified through experiments, so as to accurately explain the pharmacodynamic mechanism of Traditional Chinese medicine.

Delavatine A attenuates OGD/R-caused PC12 cell injury and apoptosis through suppressing the MKK7/JNK signaling pathway

Delavatine A (DA) is an unusual isoquinoline alkaloid with a novel skeleton isolated from Chinese folk medicine Incarvillea delavayi. Studies conducted in our lab have demonstrated that DA has potential anti-inflammatory activity in LPS-treated BV-2 cells. DA, however, has not been studied for its protective effect on neuronal cells yet. Thus, to explore whether DA can protect neurons, oxygen and glucose deprivation/reperfusion (OGD/R)-injured PC12 cell and middle cerebral artery occlusion/reperfusion (MCAO/R) rat model were used to assess the protective efficacy of DA against OGD/R damaged PC12 cells and MCAO/R injured rats. Our results demonstrated that DA pretreatment (0.31-2.5 μM) dose-dependently increased cell survival and mitochondrial membrane potential (MMP), whereas it lowered the leakage of lactate dehydrogenase (LDH), intracellular cumulation of Ca²⁺, and overproduction of reactive oxygen species (ROS), and inhibited the apoptosis rate in OGD/R-injured PC12 cells. Western blot demonstrated that DA pretreatment lowered the expression of apoptotic proteins and repressed the activation of the MKK7/JNK pathway. It was also found that the neuroprotective efficacy of DA was significantly reversed by co-treatment with the JNK agonist anisomycin, suggesting that DA reduced PC12 cell injury and apoptosis by suppressing the MKK7/JNK pathway. Furthermore, DA oral administration greatly alleviated the neurological dysfunction and reduced the infarct volume of MCAO/R rats. Taken together, DA could ameliorate OGD/R-caused PC12 cell injury and improve brain ischemia/reperfusion (I/R) damage in MCAO/R rats, and its neuroprotection might be attributed to suppressing the MKK7/JNK signaling pathway.

Proteinopathies and Neurotrauma: Update on Degenerative Cascades

Neurotrauma, especially repetitive neurotrauma, is associated with the development of progressive neurodegeneration leading to chronic traumatic encephalopathy (CTE). Exposure to neurotrauma regularly occurs during sports and military service, often not requiring medical care. However, exposure to severe and/or repeated sub-clinical neurotrauma has been shown cause physical and psychological disability, leading to reduce life expectancy. Misfolding of proteins, or proteinopathy, is a pathological hallmark of CTE, in which chronic injury leads to local and diffuse protein aggregates. These aggregates are an overlapping feature of many neurodegenerative diseases such as CTE, Alzheimer's Disease, Parkinsons disease. Neurotrauma is also a significant risk factor for the development of these diseases, however the mechanism's underlying this association are not well understood. While phosphorylated tau aggregates are the primary feature of CTE, amyloid-beta, Transactive response DNA-binding protein 43 (TDP-43), and alpha-synuclein (αSyn) are also well documented. Aberrant misfolding of these proteins has been shown to disrupt brain homeostasis leading to neurodegeneration in a disease dependent manor. In CTE, the interaction between proteinopathies and their associated neurodegeneration is a current area of study. Here we provide an update on current literature surrounding the prevalence, characteristics, and pathogenesis of proteinopathies in CTE.

Pivotal regulatory roles of traditional Chinese medicine in ischemic stroke via inhibition of NLRP3 inflammasome

ETHNOPHARMACOLOGICAL RELEVANCE

Many studies have demonstrated the powerful neuroprotection abilities of multiple traditional Chinese medicines (TCMs) against NLRP3 inflammasome-mediated ischemic cerebral injury. These TCMs may be in the form of TCM prescriptions, Chinese herbal medicines and their extracts, and TCM monomers.

AIM OF THE STUDY

This review aimed to analyze and summarize the existing knowledge on the assembly and activation of the NLRP3 inflammasome and its role in the pathogenesis of ischemic stroke (IS). We also summarized the mechanism of action of the various TCMs on the NLRP3 inflammasome, which may provide new insights for the management of IS.

MATERIALS AND METHODS

We reviewed recently published articles by setting the keywords "NLRP3 inflammasome" and "traditional Chinese medicines" along with "ischemic stroke"; "NLRP3 inflammasome" and "ischemic stroke" along with "natural products" and so on in Pubmed and GeenMedical.

RESULTS

According to recent studies, 16 TCM prescriptions (officially authorized products and clinically effective TCM prescriptions), 7 Chinese herbal extracts, and 29 TCM monomers show protective effects against IS through anti-inflammatory, anti-oxidative stress, anti-apoptotic, and anti-mitochondrial autophagy effects.

CONCLUSIONS

In this review, we analyzed studies on the involvement of NLRP3 in IS therapy. Further, we comprehensively and systematically summarized the current knowledge to provide a reference for the further application of TCMs in the treatment of IS.

Rhodiola crenulate alleviates hypobaric hypoxia-induced brain injury via adjusting NF-κB/NLRP3-mediated inflammation

BACKGROUND

Rhodiola crenulate (R. crenulate), a famous Tibetan medicine, has been demonstrated to possess superiorly protective effects in high-altitude hypoxic brain injury (HHBI). However, its mechanisms on HHBI are still largely unknown.

METHODS

Herein, the protective effects and underlying mechanisms of R. crenulate on HHBI of BABL/c mice were explored through in vivo experiments. The mice model of HHBI was established using an animal hypobaric and hypoxic chamber. R. crenulate extract (RCE) (0.5, 1.0 and 2.0 g/kg) was given by gavage for 7 days. Pathological changes and neuronal viability of mice hippocampus and cortex were evaluated using H&E and Nissl staining, respectively. The brain water content (BWC) in mice was determined by calculating the ratio of dry to wet weight of brain tissue. And serum of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH-Px) and lactate dehydrogenase (LDH) were detected via commercial biochemical kits. Synchronously, the contents of total antioxidant capacity (T-AOC), lactic acid (LA), adenosine triphosphate (ATP), succinate dehydrogenase (SDH), pyruvate kinase (PK), Ca²⁺-Mg²⁺-ATPcase, Na⁺-K⁺-ATPcase, TNF-α, IL-1β and IL-6 in brain tissue were quantitative analysis by corresponding ELISA assay. Subsequently, NLRP3, ZO-1, claudin-5, occluding, p-p65, p65, ASC, cleaved-caspase-1, caspase-1 and IL-18 were determined by immunofluorescent and western blot analyses.

RESULTS

The results demonstrated that RCE remarkably alleviated pathological damage, BWC, as well enhanced neuronal viability. Furthermore, the oxidative stress injuries were reversely abrogated after RCE treatment, evidenced by the increases of SOD, GSH-Px and T-AOC, while the decreases of MDA and LDH contents. Marvelously, the administration of RCE rectified and balanced the abnormal energy metabolism via elevating the levels of ATP, SDH, PK, Ca²⁺-Mg²⁺-ATPcase and Na⁺-K⁺-ATPcase, and lowering LA. Simultaneously, the expression of tight junction proteins (ZO-1, claudin-5 and occludin) was enhanced, illustrating RCE treatment might maintain the integrity of blood-brain barrier (BBB). Additionally, RCE treatment confined the contents of IL-6, IL-1β and TNF-α, and attenuated fluorescent signal of NLRP3 protein. Concurrently, the results of western blot indicated that RCE treatment dramatically restrained p-p65/p65, ASC, NLRP3, cleaved-caspase-1/caspase-1 and IL-18 protein expressions in brain tissues of mice.

CONCLUSION

RCE may afford a protectively intervention in HHBI of mice through suppressing the oxidative stress, improving energy metabolism and the integrity of BBB, and subsiding inflammatory responses via the NF-κB/NLRP3 signaling pathway. As a promising agent for the treatment of mice HHBI, the deep-crossing molecular mechanisms of R. crenulate still needs to be further elucidated to identify novel core hub targets.

Salidroside, a phenyl ethanol glycoside from Rhodiola crenulata, orchestrates hypoxic mitochondrial dynamics homeostasis by stimulating Sirt1/p53/Drp1 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola crenulata is clinically used to combat hypobaric hypoxia brain injury at high altitude with the function of invigorating Qi and promoting blood circulation in Tibetan medicine. Salidroside (Sal), an active compound identified from Rhodiola species, has been shown to exert neuroprotective effects against hypoxic brain injury. However, its mitochondrial protective mechanisms remain largely unknown.

AIM OF THE STUDY

The present study aimed to explore the mitochondrial protection of Sal and the involved mechanisms related to mitochondrial dynamics homeostasis on hypoxia-induced injury of HT22 cells.

MATERIALS AND METHODS

Hypoxic condition was performed as cells cultured in a tri-gas incubator with 1% O₂, 5% CO₂ and 94% N₂. We firstly investigated the effects of different concentrations of Sal on the viability of normal or hypoxic HT22 cells. Whereafter, the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), adenosine triphosphate (ATP) and Na⁺-K⁺-ATPase were tested by commercial kits. Meanwhile, mitochondrial superoxide, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were determined by specific labeled probes. Mitochondrial morphology was detected by mito-tracker green with confocal microscopy. Additionally, the potential interactions of Sal with Sirt1/p53/Drp1 signaling pathway-related proteins were predicted and tested by molecular docking and localized surface plasmon resonance (LSPR) techniques, respectively. Furthermore, the protein levels of Sirt1, p53, ac-p53, Drp1, p-Drp1(s616), Fis1 and Mfn2 were estimated by western blot analysis.

RESULTS

Sal alleviated hypoxia-induced oxidative stress in HT22 cells as evidenced by increased cell viability and SOD activity, while decreased LDH release and MDA content. The protected mitochondrial function by Sal treatment was indicated by the increases of ATP level, Na⁺-K⁺-ATPase activity and MMP. Miraculously, Sal reduced hypoxia-induced mitochondrial fission, while increased mitochondrial tubular or linear morphology. The results of molecular docking and LSPR confirmed the potential binding of Sal to proteins Sirt1, p53, Fis1 and Mfn2 with affinity values 1.38 × 10^-2, 5.26 × 10^-3, 6.46 × 10^-3 and 7.26 × 10^-3 KD, respectively. And western blot analysis further demonstrated that Sal memorably raised the levels of Sirt1 and Mfn2, while decreased the levels of ac-p53, Drp1, p-Drp1 (s616) and Fis1.

CONCLUSION

Collectively, our data confirm that Sal can maintain mitochondrial dynamics homeostasis by activating the Sirt1/p53/Drp1 signaling pathway.

Salvianolic Acid B Attenuates Iopromide-Induced Renal Tubular Epithelial Cell Injury by Inhibiting the TLR4/NF-κB/NLRP3 Signaling Pathway

Postcontrast acute kidney injury (PC-AKI) is directly caused by the use of contrast, indicating a clear causal relationship between the contrast and the injury. Salvianolic acid B (Sal B), a water-soluble compound of Salvia miltiorrhiza, has a potent anti-inflammatory effect. We conducted a study to explore whether the protective effect of Sal B on iopromide-induced injury in human proximal tubular epithelial cells (HK-2 cells) is related to inhibition of the TLR4/NF-κB/NLRP3 signal pathway. The results showed that 100 μmol/L Sal B counteracted the decrease in cell viability, the increase of ROS and the number of apoptotic cells, and the decrease of mitochondrial membrane potential (ΔΨm) induced by iopromide. Molecular docking analysis showed that Sal B binds TLR4 and NLRP3 proteins. Moreover, 100 μmol/L Sal B also decreased the expression of TLR4, NLRP3, ASC, Caspase-1, IL-18, IL-1β, TNF-α, p-NF-κB, cleaved caspase-3, and the ratio of Bax/Bcl-2 induced by iopromide. TAK-242, a TLR4 antagonist, was added to further explore the mechanism of Sal B. However, the cotreatment group with TAK-242 and Sal B had no significant difference in cell viability and apoptosis rate compared to the treatment group with TAK-242 or Sal B alone. These results indicated that Sal B can inhibit the TLR4/NF-κB/NLRP3 signal pathway, resulting in the alleviation of iopromide-induced HK-2 cell injury.

Friend or Foe: The Relativity of (Anti)oxidative Agents and Pathways

An element, iron, a process, the generation of reactive oxygen species (ROS), and a molecule, ascorbate, were chosen in our study to show their dual functions and their role in cell fate decision. Iron is a critical component of numerous proteins involved in metabolism and detoxification. On the other hand, excessive amounts of free iron in the presence of oxygen can promote the production of potentially toxic ROS. They can result in persistent oxidative stress, which in turn can lead to damage and cell death. At the same time, ROS—at strictly regulated levels—are essential to maintaining the redox homeostasis, and they are engaged in many cellular signaling pathways, so their total elimination is not expedient. Ascorbate establishes a special link between ROS generation/elimination and cell death. At low concentrations, it behaves as an excellent antioxidant and has an important role in ROS elimination. However, at high concentrations, in the presence of transition metals such as iron, it drives the generation of ROS. In the term of the dual function of these molecules and oxidative stress, ascorbate/ROS-driven cell deaths are not necessarily harmful processes—they can be live-savers too.

Imeglimin Is Neuroprotective Against Ischemic Brain Injury in Rats-a Study Evaluating Neuroinflammation and Mitochondrial Functions

Imeglimin is a novel oral antidiabetic drug modulating mitochondrial functions. However, neuroprotective effects of this drug have not been investigated. The aim of this study was to investigate effects of imeglimin against ischemia-induced brain damage and neurological deficits and whether it acted via inhibition of mitochondrial permeability transition pore (mPTP) and suppression of microglial activation. Ischemia in rats was induced by permanent middle cerebral artery occlusion (pMCAO) for 48 h. Imeglimin (135 μg/kg/day) was injected intraperitoneally immediately after pMCAO and repeated after 24 h. Immunohistochemical staining was used to evaluate total numbers of neurons, astrocytes, and microglia as well as interleukin-10 (IL-10) producing cells in brain slices. Respiration of isolated brain mitochondria was assessed using high-resolution respirometry. Assessment of ionomycin-induced mPTP opening in intact cultured primary rat neuronal, astrocytic, and microglial cells was performed using fluorescence microscopy. Treatment with imeglimin significantly decreased infarct size, brain edema, and neurological deficits after pMCAO. Moreover, imeglimin protected against pMCAO-induced neuronal loss as well as microglial proliferation and activation, and increased the number of astrocytes and the number of cells producing anti-inflammatory cytokine IL-10 in the ischemic hemisphere. Imeglimin in vitro acutely prevented mPTP opening in cultured neurons and astrocytes but not in microglial cells; however, treatment with imeglimin did not prevent ischemia-induced mitochondrial respiratory dysfunction after pMCAO. This study demonstrates that post-stroke treatment with imeglimin exerts neuroprotective effects by reducing infarct size and neuronal loss possibly via the resolution of neuroinflammation and partly via inhibition of mPTP opening in neurons and astrocytes.

Understanding the Dynamics of the Transient and Permanent Opening Events of the Mitochondrial Permeability Transition Pore with a Novel Stochastic Model

The mitochondrial permeability transition pore (mPTP) is a non-selective pore in the inner mitochondrial membrane (IMM) which causes depolarization when it opens under conditions of oxidative stress and high concentrations of Ca2+. In this study, a stochastic computational model was developed to better understand the dynamics of mPTP opening and closing associated with elevated reactive oxygen species (ROS) in cardiomyocytes. The data modeled are from "photon stress" experiments in which the fluorescent dye TMRM (tetramethylrhodamine methyl ester) is both the source of ROS (induced by laser light) and sensor of the electrical potential difference across the IMM. Monte Carlo methods were applied to describe opening and closing of the pore along with the Hill Equation to account for the effect of ROS levels on the transition probabilities. The amplitude distribution of transient mPTP opening events, the number of transient mPTP opening events per minute in a cell, the time it takes for recovery after transient depolarizations in the mitochondria, and the change in TMRM fluorescence during the transition from transient to permanent mPTP opening events were analyzed. The model suggests that mPTP transient open times have an exponential distribution that are reflected in TMRM fluorescence. A second multiple pore model in which individual channels have no permanent open state suggests that 5-10 mPTP per mitochondria would be needed for sustained mitochondrial depolarization at elevated ROS with at least 1 mPTP in the transient open state.

Dengzhan Xixin injection derived from a traditional Chinese herb Erigeron breviscapus ameliorates cerebral ischemia/reperfusion injury in rats via modulation of mitophagy and mitochondrial apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Dengzhan Xixin injection (DX), a preparation of extracts from traditional Chinese medicine Erigeron breviscapus (Vaniot) Hand.-Mazz., has been widely used in clinical treatment of cerebral ischemia sequelae in China for a long history. However, its underlying mechanisms remain unclear.

AIM OF THE STUDY

The objective of this present study aimed to investigate the therapeutic effects of DX on cerebral ischemia/reperfusion (I/R) injury in a rat model. Meanwhile, its underlying molecular mechanisms on mitochondrial protection were further interpreted.

MATERIALS AND METHODS

The major components of DX were detected by high-performance liquid chromatography analysis. The model of cerebral I/R injury was established by middle cerebral artery occlusion (MCAO) in SD rats. We firstly performed neurobehavioral score, the regional cerebral blood flow (rCBF) assay, and TTC, HE and Nissl staining for evaluating the effects of DX on I/R injury. And then, the cortical levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) were determined by commercial kits. Whereafter, real time-PCR and transmission electron microscopy were employed to investigate the relative copy number of mitochondrial DNA (mtDNA) and neuronal ultrastructure changes, respectively. Further, the potential interactions of major components in DX with mitophagy/apoptosis-related proteins were predicted by Schrodinger molecular docking. The expression of mitophagy-related proteins LC3, p62, TOM20, PINK1 and Parkin was estimated by western blot and immunofluorescence analyses. Furthermore, TUNEL staining and western blot were used to detect the apoptotic phenomenon and the protein expression of Bax, Bcl-2, Cytochrome c (Cyto-c) and cleaved Caspase-3.

RESULTS

DX mainly contains scutellarin, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, 4,5-O-dicaffeoylquinic acid, caffeic acid and 5-O-caffeoylquinic acid. Compared with the model group, DX could remarkably relieve ischemia-provoked neurological deficit, rCBF deficiency and cerebral infarction. Pathological changes and neuronal loss in a MCAO model of rats were memorably ameliorated by DX administration. Meanwhile, DX reduced the surged ROS and MDA, while increased the level of SOD. Notably, DX treatment conversed the collapse of ATP and MMP, along with decreased in the relative copy number of mtDNA, contributing to the maintaining of mitochondrial ultrastructure via the increased number of autophagy lysosomes. The representative ingredients in DX had a potential bind with the active sites of mitophagy/apoptosis-related proteins. DX stimulated the protein expression of LC3, PINK1 and Parkin, while reduced the levels of p62 and TOM20. In addition, DX confined TUNEL-positive cell rate with the decreased expressions of Bax, Cyto-c and cleaved Caspase-3 as well as the increased Bcl-2 level.

CONCLUSIONS

We demonstrated that the protection of DX against brain ischemia could attribute to alleviating mitochondrial damage by upregulating mitophagy and inhibiting mitochondria-mediated apoptosis.

Double-activation of mitochondrial permeability transition pore opening via calcium overload and reactive oxygen species for cancer therapy

BACKGROUND

Calcium ions (Ca²⁺) participates in various intracellular signal cascades and especially plays a key role in pathways relevant to cancer cells. Mitochondrial metabolism stimulated by calcium overload can trigger the opening of the mitochondrial permeability transition pore (MPTP), which leads to cancer cell death.

METHODS

Herein, a mitochondrial pathway for tumour growth inhibition was built via the double-activation of MPTP channel. Fe²⁺ doped covalent organic frameworks (COF) was synthesised and applied as template to grow CaCO₃ shell. Then O₂ was storaged into Fe²⁺ doped COF, forming O₂-FeCOF@CaCO₃ nanocomposite. After modification with folic acid (FA), O₂-FeCOF@CaCO₃@FA (OFCCF) can target breast cancer cells and realize PDT/Ca²⁺ overload synergistic treatment.

RESULTS

COF can induce the production of ¹O₂ under 650 nm irradiation for photodynamic therapy (PDT). Low pH and hypoxia in tumour microenvironment (TME) can activate the nanocomposite to release oxygen and Ca²⁺. The released O₂ can alleviate hypoxia in TME, thus enhancing the efficiency of COF-mediated PDT. Abundant Ca²⁺ were released and accumulated in cancer cells, resulting in Ca²⁺ overload. Notably, the reactive oxygen species (ROS) and Ca²⁺ overload ensure the sustained opening of MPTP, which leads to the change of mitochondria transmembrane potential, the release of cytochrome c (Cyt c) and the activation of caspases 3 for cancer cell apoptosis.

CONCLUSION

This multifunctional nanosystem with TME responded abilities provided a novel strategy for innovative clinical cancer therapy.

Metabonomics Study on Naotaifang Extract Alleviating Neuronal Apoptosis after Cerebral Ischemia-Reperfusion Injury

Naotaifang extract (NTE) is a clinically effective traditional Chinese medicine compound for cerebral ischemia-reperfusion injury. Although NTE can achieve neuroprotective function through different mechanisms, the pharmacodynamic substances of NTE corresponding to these mechanisms have rarely been reported. Alleviating or inhibiting neuronal apoptosis is an important way to achieve neuroprotection. Accordingly, this study has evaluated the effects of NTE on alleviating neuronal apoptosis after cerebral ischemia-reperfusion injury from two levels of cells and tissues. Meanwhile, the serum pharmacochemistry of NTE was analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with the guidance of Chinmedomics. The results included three aspects: (1) NTE could significantly alleviate neuronal apoptosis caused by in vitro cellular models and in vivo animal models; (2) a total of 21 serum differential metabolites was discovered, including adenosine, inosine, ferulic acid, calycosin, salidroside, 6-gingerol, 2-methoxycinnamaldehyde, and so on; (3) the metabolic pathway regulated by NTE was mainly purine metabolism. From these results, it can be concluded that alleviating neuronal apoptosis by NTE after cerebral ischemia-reperfusion injury is one of the important mechanisms to achieve neuroprotection. The pharmacodynamic substances of NTE for alleviating neuronal apoptosis on the one hand are related to components directly absorbed into blood, such as ferulic acid, calycosin, salidroside, 6-gingerol, and 2-methoxycinnamaldehyde and on the other hand are also closely linked to its indirect regulation of purine metabolism in the body to produce adenosine and inosine. Therefore, our research not only identified the main pharmacodynamic substances of NTE that alleviated neuronal apoptosis but also provided a methodological reference for studying other neuroprotective effects of NTE.

Targeting mitochondrial permeability transition pore ameliorates PM2.5-induced mitochondrial dysfunction in airway epithelial cells

Particulate matter with aerodynamic diameter not larger than 2.5 μm (PM_2.5) escalated the risk of respiratory diseases. Mitochondrial dysfunction may play a pivotal role in PM_2.5-induced airway injury. However, the potential effect of PM_2.5 on mitochondrial permeability transition pore (mPTP)-related airway injury is still unknown. This study aimed to investigate the role of mPTP in PM_2.5-induced mitochondrial dysfunction in airway epithelial cells in vitro. PM_2.5 significantly reduced cell viability and caused apoptosis in BEAS-2B cells. We also found PM_2.5 caused cellular and mitochondrial morphological alterations, evidenced by the disappearance of mitochondrial cristae, mitochondrial swelling, and the rupture of the outer mitochondrial membrane. PM_2.5 induced mPTP opening via upregulation of voltage-dependent anion-selective channel (VDAC), leading to deprivation of mitochondrial membrane potential, increased mitochondrial reactive oxygen species (ROS) generation and intracellular calcium level. PM_2.5 suppressed mitochondrial respiratory function by reducing basal and maximal respiration, and ATP production. The mPTP targeting compounds cyclosporin A [CsA; a potent inhibitor of cyclophilin D (CypD)] and VBIT-12 (a selective VDAC1 inhibitor) significantly inhibited PM_2.5-induced mPTP opening and apoptosis, and preserved mitochondrial function by restoring mitochondrial membrane potential, reducing mitochondrial ROS generation and intracellular calcium content, and maintaining mitochondrial respiration function. Our data further demonstrated that PM_2.5 caused reduction in nuclear expressions of PPARγ and PGC-1α, which were reversed in the presence of CsA. These findings suggest that mPTP might be a potential therapeutic target in the treatment of PM_2.5-induced airway injury.

Cangfudaotan decoction inhibits mitochondria-dependent apoptosis of granulosa cells in rats with polycystic ovarian syndrome

Polycystic ovary syndrome (PCOS) is a universal endocrine and metabolic disorder prevalent in reproductive aged women. PCOS is often accompanied with insulin resistance (IR) which is an essential pathological factor. Although there is no known cure for PCOS, cangfudaotan (CFDT) decoction is widely used for the treatment of PCOS; nevertheless, the underlying mechanism is not clear. In this study, 40 Sprague-Dawley (SD) rats (female) were randomized to 4 groups, namely the control group, PCOS group, PCOS+CFDT group, and PCOS+metformin group. The rats in the control group were fed a normal-fat diet, intraperitoneally injected with 0.5% carboxymethyl cellulose (CMC, 1 mL/kg/d) for 21 days and orally given saline (1 mL/kg/d) for the next 4 weeks. The rats in the PCOS group, PCOS+CFDT group, and PCOS+Metformin group were fed a high-fat diet (HFD) and intraperitoneally injected with letrozole (1.0 mg/kg) for 21 days. During this period, we recorded the body weight, estrous cycles, and rate of pregnancy in all rats. We also observed the ovarian ultrastructure. Blood glucose indices, serum hormones, and inflammatory factors were also recorded. Then, we detected apoptotic and mitochondrial function, and observed mitochondria in ovarian granular cells by transmission electron microscopy. We also detected genes of ASK1/JNK pathway at mRNA and protein levels. The results showed that CFDT alleviated pathohistological damnification and apoptosis in PCOS rat model. In addition, CFDT improved ovarian function, reduced inflammatory response, inhibited apoptosis of granular cells, and inhibited the operation of ASK1/JNK pathway. These findings demonstrate the occurrence of ovary mitochondrial dysfunction and granular cell apoptosis in PCOS. CFDT can relieve mitochondria-dependent apoptosis by inhibiting the ASK1/JNK pathway in PCOS rats.

Immune Modulation as a Key Mechanism for the Protective Effects of Remote Ischemic Conditioning After Stroke

Remote ischemic conditioning (RIC), which involves a series of short cycles of ischemia in an organ remote to the brain (typically the limbs), has been shown to protect the ischemic penumbra after stroke and reduce ischemia/reperfusion (IR) injury. Although the exact mechanism by which this protective signal is transferred from the remote site to the brain remains unclear, preclinical studies suggest that the mechanisms of RIC involve a combination of circulating humoral factors and neuronal signals. An improved understanding of these mechanisms will facilitate translation to more effective treatment strategies in clinical settings. In this review, we will discuss potential protective mechanisms in the brain and cerebral vasculature associated with RIC. We will discuss a putative role of the immune system and circulating mediators of inflammation in these protective processes, including the expression of pro-and anti-inflammatory genes in peripheral immune cells that may influence the outcome. We will also review the potential role of extracellular vesicles (EVs), biological vectors capable of delivering cell-specific cargo such as proteins and miRNAs to cells, in modulating the protective effects of RIC in the brain and vasculature.

Baoyuan Capsule promotes neurogenesis and neurological functional recovery through improving mitochondrial function and modulating PI3K/Akt signaling pathway

BACKGROUND

Bao Yuan Capsule (BYC) is a patented Chinese medicinal formula for health promotion but its application for ischemic stroke remains unknown. In this study, we proposed the hypothesis that BYC could promote neurogenesis and neurological functional recovery through promoting mitochondrial function and activating PI3K/Akt signaling pathway.

METHODS

We firstly performed chemical identification studies by using QIT-TOF-MS technology. Then, we investigated the effects of BYC (1 g/kg, 2 g/kg, 4 g/kg per day) on improving the recovery of the neurological functions in transient middle cerebral artery occlusion (MCAO) ischemic mice.

RESULTS

We tentatively characterized 36 compounds from the BYC extractions. At dosage of 4 g/kg, BYC effectively improved locomotor ability, attenuated anxiety-like behaviors, and enhanced the exploring behaviors, learning and memory capability in the transient MCAO ischemic mice. BYC treatment promoted neural stem cell differentiations in the subventricular zone (SVZ) and subgranular zone (SGZ) of the MCAO mice. BYC also up-regulated the expression of Aconitase 2 (ACO2), Succinate dehydrogenase complex, subunit A (SDHA), phosphorylation of AMP-activated protein kinase (p-AMPK), protein kinase B (p-Akt) and glycogen synthase kinase 3β (p-GSK3β) in the hippocampus of the MCAO mice. BYC (200 µg/ml) significantly improved the mitochondrial functions in cultured mouse multipotent neural stem like C17.2 cells. BYC treatment also promoted neuronal differentiations in the C17.2 cells under oxygen-glucose deprivation (OGD) condition. The neurogenetic effects were abolished by co-treatments of ATP synthesis inhibitor oligomycin and PI3K/Akt inhibitor wortmannin. Moreover, Akt phosphorylation was dramatically reduced by oligomycin.

CONCLUSION

BYC could promote neurogenesis and neurological functional recovery in post ischemic brains by regulating the mitochondrial functions and Akt signaling pathway.

Dehydrocostuslactone attenuated oxygen and glucose deprivation/reperfusion-induced PC12 cell injury through inhibition of apoptosis and autophagy by activating the PI3K/AKT/mTOR pathway

The purpose of this study is to investigate the protective effect of dehydrocostuslactone (DHL) on PC12 cells injury induced by oxygen and glucose deprivation/reperfusion (OGD/R) and its possible mechanism on the PI3K/AKT/mTOR pathway. The maestro 11.1 software was used to predict the binding sites of DHL with LC3, Beclin-1, PI3K, AKT, mTOR, Bax, Bcl-2, Caspase-3, Caspase-9, and Caspase-7. We used a cellular model of 2 h of OGD and 24 h of reperfusion to mimic cerebral ischemia-reperfusion injury. Cells were treated with DHL during the reperfusion phase. The docking results showed that DHL had binding sites with LC3, Beclin-1, PI3K, AKT, mTOR, Bax, Bcl-2, Caspase-3, Caspase-9, and Caspase-7. The expression levels of autophagy-related proteins, LC3 and Beclin-1 increased while P-PI3K, P-AKT, and P-mTOR decreased. Apoptosis-related proteins, namely, Bax, Cyto-c, Caspase-3, Caspase-7, Caspase-9 increased, but the anti-apoptosis Bcl-2 protein decreased. However, DHL effectively inhibited these undesirable changes induced by OGD/R in PC12 cells. Our results suggested that DHL attenuated OGD/R-induced neuronal injury by inhibiting apoptosis and autophagy by activating PI3K/AKT/mTOR signaling. This inhibition can improve cell survival and offer evidence for the beneficial effects of DHL on the nervous system.

Therapeutic Approach of Flavonoid in Ameliorating Diabetic Cardiomyopathy by Targeting Mitochondrial-Induced Oxidative Stress

Diabetes cardiomyopathy is one of the key factors of mortality among diabetic patients around the globe. One of the prior contributors to the progression of diabetic cardiomyopathy is cardiac mitochondrial dysfunction. The cardiac mitochondrial dysfunction can induce oxidative stress in cardiomyocytes and was found to be the cause of majority of the heart morphological and dynamical changes in diabetic cardiomyopathy. To slow down the occurrence of diabetic cardiomyopathy, it is crucial to discover therapeutic agents that target mitochondrial-induced oxidative stress. Flavonoid is a plentiful phytochemical in plants that shows a wide range of biological actions against human diseases. Flavonoids have been extensively documented for their ability to protect the heart from diabetic cardiomyopathy. Flavonoids' ability to alleviate diabetic cardiomyopathy is primarily attributed to their antioxidant properties. In this review, we present the mechanisms involved in flavonoid therapies in ameliorating mitochondrial-induced oxidative stress in diabetic cardiomyopathy.

Local and Systemic Factors Drive Ectopic Osteogenesis in Regenerating Muscles of Spinal-Cord-Injured Mice in a Lesion-Level-Dependent Manner

Neuroimmune dysfunction is thought to promote the development of several acute and chronic complications in spinal cord injury (SCI) patients. Putative roles for adrenal stress hormones and catecholamines are increasingly being recognized, yet how these adversely affect peripheral tissue homeostasis and repair under SCI conditions remains elusive. Here, we investigated their influence in a mouse model of SCI with acquired neurogenic heterotopic ossification. We show that spinal cord lesions differentially influence muscular regeneration in a level-dependent manner and through a complex multi-step process that creates an osteopermissive environment within the first hours of injury. This cascade of events is shown to critically involve adrenergic signals and drive the acute release of the neuropeptide, substance P. Our findings generate new insights into the kinetics and processes that govern SCI-induced deregulations in skeletal muscle homeostasis and regeneration, thereby aiding the development of sequential therapeutic strategies that can prevent or attenuate neuromusculoskeletal complications in SCI patients.

Aloe-emodin prevents nerve injury and neuroinflammation caused by ischemic stroke via the PI3K/AKT/mTOR and NF-κB pathway

Ischemic stroke (IS) caused by cerebral arterial occlusion is the leading cause of global morbidity and mortality. Cellular oxidative stress and inflammation play a vital role in the pathological process of neural damage in IS. It is necessary to develop functional food or drugs, which target neuroinflammation and oxidation mechanisms against IS. The molecule compound aloe-emodin (AE) is derived from aloe and rhubarb. However, the exact mechanism of the pharmacological action of AE on IS remains unclear. Here, for aiming to demonstrate the mechanism of AE, our study explored the middle cerebral occlusion reperfusion (MCAO/R) rats in vivo, oxygen and glucose deprivation reperfusion (OGD/R), and lipopolysaccharide (LPS)-stimulated cells in vitro. We found that AE significantly improved the infarct size and behavioral score of MCAO/R rats, decreased the expression of TNF-α, MDA, LDH, Caspase 3, and increased the expression of SOD, Bcl-2/Bax. Liquid chromatography-mass spectrometry (LC/MS) results showed that AE could penetrate the blood-brain barrier in the sham group and MCAO/R group. In vitro, AE significantly protected SH-SY5Y cells from the insult of OGD/R and reduced the production of inflammatory cytokines in BV2 cells stimulated by LPS. In vivo and in vitro, western blot analysis results showed that AE significantly increased the expression of PI3K, AKT and mTOR proteins. In addition, AE significantly decreased NF-κB protein expression in BV2 cells. The use of AKT-specific inhibitor MK-2206 2HCL to inhibit AKT expression can block the protective effect of AE on SH-SY5Y cells subjected to OGD/R insults. Overall, our study suggests that AE protected against cerebral ischemia-reperfusion injury probably via the PI3K/AKT/mTOR and NF-κB signaling pathways. Thus, these results indicated that AE could be a promising first-line therapy for preventing and treating ischemic stroke and can be used as functional food.

The mitochondrial permeability transition pore: an evolving concept critical for cell life and death

In this review, we summarize current knowledge of perhaps one of the most intriguing phenomena in cell biology: the mitochondrial permeability transition pore (mPTP). This phenomenon, which was initially observed as a sudden loss of inner mitochondrial membrane impermeability caused by excessive calcium, has been studied for almost 50 years, and still no definitive answer has been provided regarding its mechanisms. From its initial consideration as an in vitro artifact to the current notion that the mPTP is a phenomenon with physiological and pathological implications, a long road has been travelled. We here summarize the role of mitochondria in cytosolic calcium control and the evolving concepts regarding the mitochondrial permeability transition (mPT) and the mPTP. We show how the evolving mPTP models and mechanisms, which involve many proposed mitochondrial protein components, have arisen from methodological advances and more complex biological models. We describe how scientific progress and methodological advances have allowed milestone discoveries on mPTP regulation and composition and its recognition as a valid target for drug development and a critical component of mitochondrial biology.

Novel arylidene malonate derivative, KM-34, showed neuroprotective effects on in vitro and in vivo models of ischemia/reperfusion

Cerebral ischemia constitutes the most frequent type of cerebrovascular disease. The reduction of blood supply to the brain initiates the ischemic cascade starting from ionic imbalance to subsequent glutamate excitotoxicity, neuroinflammation and oxidative stress, eventually causing neuronal death. Previously, the authors have demonstrated the in vitro cytoprotective and antioxidant effects of a new arylidene malonate derivative, KM-34, against oxidizing agents like hydrogen peroxide, glutamate or Fe3+/ascorbate. Here, we examined for the first time the neuroprotective effect of KM-34 on ischemia/reperfusion models. In vitro, treatment with 10 and 50 μM KM-34 reduced the cellular death (propidium iodide incorporation) induced by oxygen glucose deprivation (OGD) in rat organotypic hippocampal slices cultures. In vivo, stroke was induced in male Wistar rats through middle cerebral artery occlusion (MCAO), followed by 23 h of reperfusion. KM-34 was orally administered 105 min after MCAO onset. We noticed that 1 mg/kg KM-34 reduced infarct volume and neurological score, and increased the latency to fall in the Hanging Wire test compared to vehicle-treated ischemic animals. While ischemic and sham-operated groups showed similar horizontal locomotor activity, vertical counts decreased after MCAO, suggesting that vertical movements are more sensitive to the ischemic injury. Treatment with KM-34 also alleviated the mitochondrial impairment (ROS generation, swelling and membrane potential dissipation) induced by transient MCAO but not significant alterations were found in oxidative stress parameters. Overall, the study provides preclinical evidences confirming the neuroprotective effects of a novel synthetic molecule and paved the way for future investigations regarding its therapeutic potential against brain ischemia/reperfusion injury.

Molecular and Supramolecular Structure of the Mitochondrial Oxidative Phosphorylation System: Implications for Pathology

Under aerobic conditions, mitochondrial oxidative phosphorylation (OXPHOS) converts the energy released by nutrient oxidation into ATP, the currency of living organisms. The whole biochemical machinery is hosted by the inner mitochondrial membrane (mtIM) where the protonmotive force built by respiratory complexes, dynamically assembled as super-complexes, allows the F1FO-ATP synthase to make ATP from ADP + Pi. Recently mitochondria emerged not only as cell powerhouses, but also as signaling hubs by way of reactive oxygen species (ROS) production. However, when ROS removal systems and/or OXPHOS constituents are defective, the physiological ROS generation can cause ROS imbalance and oxidative stress, which in turn damages cell components. Moreover, the morphology of mitochondria rules cell fate and the formation of the mitochondrial permeability transition pore in the mtIM, which, most likely with the F1FO-ATP synthase contribution, permeabilizes mitochondria and leads to cell death. As the multiple mitochondrial functions are mutually interconnected, changes in protein composition by mutations or in supercomplex assembly and/or in membrane structures often generate a dysfunctional cascade and lead to life-incompatible diseases or severe syndromes. The known structural/functional changes in mitochondrial proteins and structures, which impact mitochondrial bioenergetics because of an impaired or defective energy transduction system, here reviewed, constitute the main biochemical damage in a variety of genetic and age-related diseases.

New insights into targeting mitochondria in ischemic injury

Stroke is the leading cause of adult disability and death worldwide. Mitochondrial dysfunction has been recognized as a marker of neuronal death during ischemic stroke. Maintaining the function of mitochondria is important for improving the survival of neurons and maintaining neuronal function. Damaged mitochondria induce neuronal cell apoptosis by releasing reactive oxygen species (ROS) and pro-apoptotic factors. Mitochondrial fission and fusion processes and mitophagy are of great importance to mitochondrial quality control. This paper reviews the dynamic changes in mitochondria, the roles of mitochondria in different cell types, and related signaling pathways in ischemic stroke. This review describes in detail the role of mitochondria in the process of neuronal injury and protection in cerebral ischemia, and integrates neuroprotective drugs targeting mitochondria in recent years, which may provide a theoretical basis for the progress of treatment of ischemic stroke. The potential of mitochondrial-targeted therapy is also emphasized, which provides valuable insights for clinical research.

Different Roles of Mitochondria in Cell Death and Inflammation: Focusing on Mitochondrial Quality Control in Ischemic Stroke and Reperfusion

Mitochondrial dysfunctions are among the main hallmarks of several brain diseases, including ischemic stroke. An insufficient supply of oxygen and glucose in brain cells, primarily neurons, triggers a cascade of events in which mitochondria are the leading characters. Mitochondrial calcium overload, reactive oxygen species (ROS) overproduction, mitochondrial permeability transition pore (mPTP) opening, and damage-associated molecular pattern (DAMP) release place mitochondria in the center of an intricate series of chance interactions. Depending on the degree to which mitochondria are affected, they promote different pathways, ranging from inflammatory response pathways to cell death pathways. In this review, we will explore the principal mitochondrial molecular mechanisms compromised during ischemic and reperfusion injury, and we will delineate potential neuroprotective strategies targeting mitochondrial dysfunction and mitochondrial homeostasis.

Mitochondrial microRNA (MitomiRs) in cancer and complex mitochondrial diseases: current status and future perspectives

Mitochondria are not only important for cellular bioenergetics but also lie at the heart of critical metabolic pathways. They can rapidly adjust themselves in response to changing conditions and the metabolic needs of the cell. Mitochondrial involvement as well as its dysfunction has been found to be associated with variety of pathological processes and diseases. mitomiRs are class of miRNA(s) that regulate mitochondrial gene expression and function. This review sheds light on the role of mitomiRs in regulating different biological processes-mitochondrial dynamics, oxidative stress, cell metabolism, chemoresistance, apoptosis,and their relevance in metabolic diseases, neurodegenerative disorders, and cancer. Insilico analysis of predicted targets of mitomiRs targeting energy metabolism identified several significantly altered pathways (needs in vivo validations) that may provide a new therapeutic approach for the treatment of human diseases. Last part of the review discusses about the clinical aspects of miRNA(s) and mitomiRs in Medicine.

The antiinflammatory effects of Xuefu Zhuyu decoction on C3H/HeJ mice with alopecia areata

BACKGROUND

As a traditional and typical prescription of prominently activating blood circulation to remove blood stasis, Xuefu Zhuyu decoction (XZD) consists of 15 kinds of herbal medicine. Clinical investigations have showed that XZD could significantly promote the new hair generation of alopecia areata (AA) patients characterized by Qi stagnation and blood stasis.

PURPOSE

The purpose of this study was executed to determine whether the mechanisms by which XZD stimulated newborn hair were related to its anti-inflammatory effects.

METHODS

Clinical AA individuals were recruited to confirm the efficies of XZD. High performance liquid chromatography (HPLC) analysis was performed to qualitatively and quantitatively determine the contents of 15 compounds in XZD. Schrodinger molecular docking and in vivo surface plasmon resonance (SPR) techniques were used to evaluate the potential binding properties of compounds to target proteins. C3H/HeJ mice were randomly assigned to groups control, AA, and the XZD administration (6.5, 13.0 and 26.0 g/kg/d). Except for mice in control group, all the mice in the other groups were treated with a 21-day chronic unpredictable mild stress (CUMS) induced AA. Hematoxylin-eosin (H&E) staining was performed to determine the degree of pathological damage to the skin. Enzyme-linked immunosorbent assay (ELISA) was performed to detect levels of interleukin-6 (IL-6), interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) and in serum and skin tissues. Western blot, immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were used to examine the expression levels of IL-6, IL-1β, TNF-α and osteopontin proteins and genes in skin tissues.

RESULTS

XZD could visibly promote hair regeneration of AA patients. The potential active ingredients in XZD prescription included at least amygdalin, hydroxysafflor yellow A, kaempferide, ferulic acid, catalpol, verbascoside, β-ecdysone, platycodin D, paeoniflorin, naringin, neohesperidin, liquiritin, glycyrrhizic acid, saikosaponin A and saikosaponin D. The results of molecular docking and SPR analysis showed that verbascoside, liquiritin, kaempferide and amygdalin showed the best potential binding properties with IL-6, IL-1β, TNF-α and osteopontin, respectively. Pathological evaluation showed that compared with the CUMS group, the administration of XZD significantly promoted hair regeneration, evidenced by increased number of skin hair follicles in C3H/HeJ AA mice. Compared with control group, ELISA data showed that the levels of IL-6, IL-1β and TNF-α in serum and skin tissues of CUMS induced AA mice were significantly increased, while XZD administration dramatically restrained the contents of the three pro-inflammatory factors. Western blot, immunohistochemistry, and qRT-PCR results further demonstrated that XZD administration notably down-regulated the protein and gene expression levels of osteopontin, IL-6, IL-1β and TNF-α in comparation with CUMS group.

CONCLUSION

XZD could dramatically ameliorate CUMS-induced AA damage in the skin of C3H/HeJ mice, possibly by suppressing the levels of IL-6, IL-1β, TNF-α and osteopontin.