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

A novel p55PIK signaling peptide inhibitor alleviates neuroinflammation via the STAT3/NF-kB signaling pathway in experimental stroke

BACKGROUND

Ischemic stroke remains the predominant contributor to mortality and disability globally. Microglia undergo rapid activation and initiate inflammatory cascade reactions by phenotypic polarization, participating in the regulation of inflammatory injury and tissue repair post-ischemic stroke. Regulating microglia-mediated neuroinflammation is a promising therapeutic strategy for ischemic stroke. Previously, we designed and synthesized a novel p55PIK inhibitor, TAT-N15 polypeptide, which presents inhibitive activity on NF-κB signaling-mediated inflammation in acute conjunctivitis and allergic rhinitis. The present study aimed to explore the therapeutic effect and mechanism of TAT-N15 on ischemia stroke.

METHODS

The mouse model of transient cerebral ischemia was made using the intraluminal filament method. After being treated with daily intraperitoneal injections of TAT-N15 (10 mg/kg) for 7 d, the neurological outcomes and the cerebral infarction volume were evaluated. Histopathology of the ischemia cerebral hemisphere was observed by H&E and Nissl staining. Neuronal survival, astrogliosis, and co-labeling of CD86/Iba1 and CD206/Iba1 were detected by immunofluorescence. The cell apoptosis was estimated by TUNEL staining. The expression levels of apoptosis-associated proteins, proinflammatory cytokines, protein markers of M1 and M2 microglia, and the phosphorylation of NF-κB and STAT3 proteins in the ischemic penumbra were detected by Western blot.

RESULTS

TAT-N15 treatment significantly decreased the infarct volume and alleviated neurological functional impairment, neuronal injury, and neuron apoptosis. Meanwhile, TAT-N15 treatment restrained the activation of microglia and astrocytes as well as the protein expression of proinflammatory cytokine in ischemic penumbra. Additionally, the administration of TAT-N15 treatment resulted in a significant reduction in the density of M1 phenotype microglia while concurrently increasing the density of M2 phenotype microglia within the ischemic penumbra. Finally, mechanical analysis unveiled that TAT-N15 exerted a substantial inhibitory effect on the protein expression of phosphorylated STAT3 and NF-κB.

CONCLUSION

TAT-N15 may inhibit neuroinflammation via regulating microglia activation and polarization through the STAT3/NF-κB pathway, which exhibits the neuroprotection effect in ischemic stroke.

Coordination environment dependence of anticancer activity in cyclometalated bismuth(III) complexes with C,O-chelating ligands

In this paper, a series of cyclometalated bismuth(III) complexes bearing C,O-bidentate ligands were synthesized and characterized by techniques such as UV-vis, NMR, HRMS, and single crystal X-ray diffraction. Meanwhile, their cytotoxicities against various human cell lines, including colon cancer cells (HCT-116), breast cancer cells (MDA-MB-231), lung cancer cells (A549), gastric cancer cells (SGC-7901), and normal embryonic kidney cells (HEK-293) were assessed in vitro. Compared with the clinical cisplatin, most of the synthesized complexes possessed significantly higher degrees of anticancer activity and selectivity, giving a selectivity index of up to 71.3. The structure-activity relationship study revealed that the anticancer performance of these bismuth(III) species depends on the factors of coordination environment surrounding the metal center, such as coordination number, coordination bonding strength, lone 6s2 electron pair stereoactivity. The Annexin V-FITC/PI double staining assay results suggested that the coordination environment-dependent cytotoxicity is ascribable to apoptosis. Western blot analysis confirmed the proposal, as evidenced by the down-regulating level of Bcl-2 and the activation of caspase-3. Furthermore, the representative complexes Bi1, Bi4, Bi6, and Bi8 exhibited relatively lower inhibitory efficiency on human ovarian cancer cells (A2780) than on its cisplatin-resistant daughter cells (A2780/cis), thus demonstrating that such compounds are capable of circumventing the cisplatin-induced resistance. This investigation elucidated the excellent anticancer performance of C,O-coordinated bismuth(III) complexes and established the correlation between cytotoxic activity and coordination chemistry, which provides a practical basis for in-depth designing and developing bismuth-based chemotherapeutics.

Exploring the neuroprotection of the combination of astragaloside A, chlorogenic acid and scutellarin in treating chronic cerebral ischemia via network analysis and experimental validation

Chronic cerebral ischemia (CCI) primarily causes cognitive dysfunction and other neurological impairments, yet there remains a lack of ideal therapeutic medications. The preparation combination of Astragalus membranaceus (Fisch.) Bunge and Erigeron breviscapus (Vant.) Hand.-Mazz have been utilized to ameliorate neurological dysfunction following cerebral ischemia, but material basis of its synergy remains unclear. The principal active ingredients and their optimal proportions in this combination have been identified through the oxygen and glucose deprivation (OGD) cell model, including astragaloside A, chlorogenic acid and scutellarin (ACS), and its efficacy in enhancing the survival of OGD PC12 cells surpasses that of the combination preparation. Nevertheless, mechanism of ACS against CCI remains elusive. In this study, 63 potential targets of ACS against CCI injury were obtained by network pharmacology, among which AKT1, CASP3 and TNF are the core targets. Subsequent analysis utilizing KEGG and GO suggested that PI3K/AKT pathway may play a crucial role for ACS in ameliorating CCI injury. Then, a right unilateral common carotid artery occlusion (rUCCAO) mouse model and an OGD PC12 cell model were established to replicate the pathological processes of CCI in vivo and in vitro. These models were utilized to explore the anti-CCI effects of ACS and its regulatory mechanisms, particularly focusing on PI3K/AKT pathway. The results showed that ACS facilitated the restoration of cerebral blood flow in CCI mice, enhanced the function of the central cholinergic nervous system, protected against ischemic nerve cell and mitochondrial damage, and improved cognitive function and other neurological impairments. Additionally, ACS upregulated the expression of p-PI3K, p-AKT, p-GSK3β and Bcl-2, and diminished the expression of Cyto-c, cleaved Caspase-3 and Bax significantly. However, the PI3K inhibitor (LY294002) partially reversed the downregulation of Bax, Cyto-c and cleaved Caspase-3 expression as well as the upregulation of p-AKT/AKT, p-GSK3β/GSK3β, and Bcl-2/Bax ratios. These findings suggest that ACS against neuronal damage in cerebral ischemia may be closely related to the activation of PI3K/AKT pathway. These results declared first time ACS may become an ideal candidate drug against CCI due to its neuroprotective effects, which are mediated by the activated PI3K/AKT pathway mitigates mitochondrial damage and prevents cell apoptosis.

Huang-Lian-Jie-Du decoction drug-containing serum inhibits IL-1β secretion from D-glucose and PA induced BV2 cells via autophagy/NLRP3 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du decoction (HLJDD), a famous traditional Chinese medicine prescription with heat-clearing and detoxifying effects, has been widely used to treat diabetes, dementia, stroke, and other diseases. However, the detailed mechanisms of HLJDD against type 2 diabetes associated cognitive dysfunction (DACD) through inhibiting interleukin-1β (IL-1β) mediated neuroinflammation remain to be further elucidated.

AIM OF THE STUDY

The aim of this study was to investigate the effect and potential mechanism of HLJDD on IL-1β secretion in a DACD model of BV2 cells induced by D-glucose and palmitic acid (PA).

MATERIALS AND METHOD

sUltra-performance liquid chromatography-quadrupole/electrostatic field orbital well high-resolution mass spectrometry technology was used to analyze the compounds in HLJDD drug-containing serum. The cytotoxicity was detected by cell counting kit-8. Enzyme-linked immunosorbent assay was used to measure the secretion of IL-1β in BV2 cells. Reactive oxygen species, glutathione, superoxide dismutase, and malondialdehyde kits were used to detect the intracellular oxidative stress levels. The autophagy level was determined by autophagy staining kit and transmission electron microscope. The expression levels of autophagy-related 7 (Atg7), P62, LC3, nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3(NLRP3), Caspase1, and IL-1β were detected by real-time PCR, immunofluorescence, and western blotting. The Atg7siRNA was transfected into BV2 cells to produce autophagy inhibitory effect. Then the effect of HLJDD drug-containing serum on IL-1β secretion in D-glucose and PA induced BV2 cells and the potential mechanism of autophagy-NLRP3 inflammasome activation were further observed.

RESULTS

Eighty-eight compounds were preliminarily identified in HLJDD drug-containing serum, among which geniposide, baicalin, palmatine, berberine, wogonoside, wogonin, and geniposidic acid were identified as the main prototype components of HLJDD into the blood. In this study, the DACD model of BV2 cells induced by high concentrations of glucose and PA was successfully constructed. HLJDD drug-containing serum significantly reduced the secretion of IL-1β and the activity of NLRP3 inflammasome with improving the oxidative stress level. Interestingly, the enhanced autophagy level was also found. After transfection of Atg7siRNA into BV2 cells, the effect of HLJDD drug-containing serum on autophagy promotion was reversed, but the inhibitory effects on IL-1β secretion, NLRP3 inflammasome activation, and oxidative stress were reduced.

CONCLUSIONS

These results indicated that the inhibition of HLJDD drug-containing serum on the IL-1β secretion in D-glucose and PA induced BV2 cells was related to autophagy promotion, the decreased NLRP3 inflammasome activation, and the improved oxidative stress. Moreover, the improvement of HLJDD drug-containing serum on IL-1β secretion, NLRP3 inflammasome activation, and oxidative stress were all closely associated with Atg7 mediated autophagy promotion. Geniposide, baicalin, palmatine, berberine, wogonoside, wogonin, and geniposidic acid may be the potential active ingredients of HLJDD drug-containing serum.

Activin A alleviates neuronal injury through inhibiting cGAS-STING-mediated autophagy in mice with ischemic stroke

Activin A plays an essential role in ischemic stroke as a well-known neuroprotective factor. We previously reported that Activin A could promote white matter remyelination. However, the exact molecular mechanism of Activin A in neuronal protection post-stroke is still unclear. In this study, the middle cerebral artery occlusion/reperfusion (MCAO/R)-induced ischemic stroke mouse model and oxygen-glucose deprivation/reoxygenation (OGD/R)-treated primary neurons were used to explore the molecular mechanism of Activin A-mediated neuroprotection against ischemic injuries. We found that Activin A significantly inhibits cGAS-STING-mediated excessive autophagy through the PI3K-PKB pathway, but not mTOR-dependent autophagy. Consequently, Activin A protected neurons against OGD/R-induced ischemic injury and improved cell survival in a dose-dependent manner. In addition, Activin A improved neurological functions and reduced infarct size of mice with MCAO/R-induced ischemic stroke by inhibiting autophagy. Furthermore, Activin A depended on ACVR1C receptor to exert neuroprotective effects in 1 h MCAO/R treated mice. Our findings showed that Activin A alleviated neuronal ischemic injury through inhibiting cGAS-STING-mediated excessive autophagy in mice with ischemic stroke, which may suggest a potential therapeutic target for ischemic stroke.

Dexmedetomidine alleviates cerebral ischemia-reperfusion injury via inhibiting autophagy through PI3K/Akt/mTOR pathway

Dexmedetomidine has been shown to protect against cerebral ischemia-reperfusion injury (CIRI). Nevertheless, the precise mechanism is obscure. In order to explore the effect of dexmedetomidine pre-conditioning on autophagy against CIRI in rats, middle cerebral artery occlusion (MCAO) was conducted to establish cerebral ischemia-reperfusion (I/R) model in male SD rats with 2 h ischemia and 24 h reperfusion. Dexmedetomidine was delivered to rats at 10, 50 and 100 µg/kg doses respectively, and LY294002, a PI3K/Akt/mTOR pathway inhibitor, was administered at 10 mg/kg intraperitoneally 30 min before MCAO. Neurological deficit score was assessed and cerebral infarct size was detected by TTC staining. Morris water maze (MWM) was performed to estimate spatial learning and memory ability. Furthermore, to detect activity of PI3K/Akt/mTOR pathway and autophagy, p-Akt, p-mTOR, Beclin-1 and LC3 were measured by western blot. Our findings revealed that 50 and 100 µg/kg of dexmedetomidine pretreatment could improve the neurological deficit score and reduce cerebral infarct size after CIRI, while these effects were markedly suppressed by LY294002. In MWM test, dexmedetomidine was confirmed to shorten escape latency and increase times across platform after CIRI. Nevertheless, LY294002 pretreatment eliminated the improvement of dexmedetomidine on spatial learning and memory ability. Furthermore, dexmedetomidine pretreatment reduced ratios of Beclin-1 and LC3II/LC3I and elevated p-Akt/Akt and p-mTOR/mTOR after CIRI. However, above effects of dexmedetomidine were partly reversed by LY294002. Overall, dexmedetomidine pretreatment exerted neuroprotection against CIRI in rats by attenuating autophagy via the PI3K/Akt/mTOR pathway.

The autophagy in ischemic stroke: A regulatory role of non-coding-RNAs

Ischemic stroke (IS) is a central nervous system neurological disorder ascribed to an acute focal trauma, with high mortality and disability, leading to a heavy burden on family and society. Autophagy is a self-digesting process by which damaged organelles and useless proteins are recycled to maintain cellular homeostasis, and plays a pivotal role in the process of IS. Non-coding RNAs (ncRNAs), mainly contains microRNA, long non-coding RNA and circular RNA, have been extensively investigated on regulation of autophagy in human diseases. Recent studies have implied that ncRNAs-regulating autophagy participates in pathophysiological process of IS, including cell apoptosis, inflammation, oxidative stress, blood-brain barrier damage and glial activation, which indicates that regulating autophagy by ncRNAs may be beneficial for IS treatment. This review summarizes the role of autophagy in IS, as well as focuses on the role of ncRNAs-mediated autophagy in IS, for the development of potential therapeutic strategies in this disease.

Anti-apoptosis effect of traditional Chinese medicine in the treatment of cerebral ischemia-reperfusion injury

Cerebral ischemia, one of the leading causes of neurological dysfunction of brain cells, muscle dysfunction, and death, brings great harm and challenges to individual health, families, and society. Blood flow disruption causes decreased glucose and oxygen, insufficient to maintain normal brain tissue metabolism, resulting in intracellular calcium overload, oxidative stress, neurotoxicity of excitatory amino acids, and inflammation, ultimately leading to neuronal cell necrosis, apoptosis, or neurological abnormalities. This paper summarizes the specific mechanism of cell injury that apoptosis triggered by reperfusion after cerebral ischemia, the related proteins involved in apoptosis, and the experimental progress of herbal medicine treatment through searching, analyzing, and summarizing the PubMed and Web Of Science databases, which includes active ingredients of herbal medicine, prescriptions, Chinese patent medicines, and herbal extracts, providing a new target or new strategy for drug treatment, and providing a reference for future experimental directions and using them to develop suitable small molecule drugs for clinical application. With the research of anti-apoptosis as the core, it is important to find highly effective, low toxicity, safe and cheap compounds from natural plants and animals with abundant resources to prevent and treat Cerebral ischemia/reperfusion (I/R) injury (CIR) and solve human suffering. In addition, understanding and summarizing the apoptotic mechanism of cerebral ischemia-reperfusion injury, the microscopic mechanism of CIR treatment, and the cellular pathways involved will help to develop new drugs.

Qilong Capsule Alleviated MPTP-Induced Neuronal Defects by Inhibiting Apoptosis, Regulating Autophagy in Zebrafish Embryo Model

Qilong capsule (QLC) originates from the famous "Buyang Huanwu decoction" prescription. It is representative of drugs used in China during recovery from stroke, but its neuroprotective mechanism of action remains obscure. HPLC was used to evaluate the similarity of 10 batches of QLC samples. Then we used a zebrafish model to study the neuroprotective effect of QLC. At 24 hpf, embryos were treated with QLC and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and zebrafish were observed the neuronal length and the number of apoptotic cells in the brain at 72 hpf. At 120 hpf, we conduct zebrafish behavioural tests. We then also used qPCR to detect the expression of genes related to autophagy and apoptosis. The results showed that QLC significantly reduced the damage of dopaminergic neurons, the number of apoptotic cells in the brain, and alleviated motor disturbances induced by MPTP. We found that the mechanism of QLC activity involved decreased neuron cell death by inhibiting mitochondrial apoptosis and autophagy, promoting autophagy, degradation of alpha-synuclein, and neuron cell growth, and rescuing the function of neurons damaged by MPTP. The results indicated that QLC protected against MPTP-induced neuron injury and provided pharmacological evidence for clinical use of QLC.

Stroke: Molecular mechanisms and therapies: Update on recent developments

Stroke, a neurological disease, is one of the leading causes of death worldwide, resulting in long-term disability in most survivors. Annual stroke costs in the United States alone were estimated at $46 billion recently. Stroke pathophysiology is complex, involving multiple causal factors, among which atherosclerosis, thrombus, and embolus are prevalent. The molecular mechanisms involved in the pathophysiology are essential to understanding targeted drug development. Some common mechanisms are excitotoxicity and calcium overload, oxidative stress, and neuroinflammation. In addition, various modifiable and non-modifiable risk factors increase the chances of stroke manifolds. Once a patient encounters a stroke, complete restoration of motor ability and cognitive skills is often rare. Therefore, shaping therapeutic strategies is paramount for finding a viable therapeutic agent. Apart from tPA, an FDA-approved therapy that is applied in most stroke cases, many other therapeutic strategies have been met with limited success. Stroke therapies often involve a combination of multiple strategies to restore the patient's normal function. Certain drugs like Gamma-aminobutyric receptor agonists (GABA), Glutamate Receptor inhibitors, Sodium, and Calcium channel blockers, and fibrinogen-depleting agents have shown promise in stroke treatment. Recently, a drug, DM199, a recombinant (synthetic) form of a naturally occurring protein called human tissue kallikrein-1 (KLK1), has shown great potential in treating stroke with fewer side effects. Furthermore, DM199 has been found to overcome the limitations presented when using tPA and/or mechanical thrombectomy. Cell-based therapies like Neural Stem Cells, Hematopoietic stem cells (HSCs), and Human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs) are also being explored as a treatment of choice for stroke. These therapeutic agents come with merits and demerits, but continuous research and efforts are being made to develop the best therapeutic strategies to minimize the damage post-stroke and restore complete neurological function in stroke patients.

Salidroside intensifies mitochondrial function of CoCl2-damaged HT22 cells by stimulating PI3K-AKT-MAPK signaling pathway

BACKGROUND

Salidroside (Sal), an active component from Rhodiola crenulata, has been confirmed to exert neuroprotective effects against hypoxia. However, its molecular mechanisms of intensifying mitochondrial function still largely unknown. In the present study, we aimed to explore the mechanisms by which Sal heightened mitochondrial function in CoCl₂-induced HT22 hypoxic injury.

METHODS

The hypoxic condition of HT22 cells was performed by CoCl₂ stimulus. We then investigated the effects of Sal on the viability of hypoxic HT22 cells by cell counting kit-8. The contents of lactate dehydrogenase (LDH) release in cultured supernatant were detected by using commercial biochemical kit. Superoxide free radical scavenging activity, total antioxidant capacity assay kit with ferric reducing ability of plasma and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) methods were employed to detect the free radical scavenging ability and antioxidant capacity of Sal. Meanwhile, intracellular reactive oxygen species (ROS), Ca2+ and mitochondrial membrane potential (MMP) were determined by corresponding specific labeled probes. Mitochondrial morphology was tested by Mito-tracker green with confocal microscopy. Hoechst 33342 and Annexin V-FITC/propidium iodide staining were also employed to evaluate the effect of Sal on cell apoptosis. Oxygen consumption rate (OCR), real-time ATP production and proton efflux rate were measured using a Seahorse analyzer. Additionally, the potential interactions of Sal with PI3K-AKT signaling pathway-related proteins were predicted and tested by molecular docking, molecular dynamics simulation (MDS) and localized surface plasmon resonance (LSPR) techniques, respectively. Furthermore, the protein levels of p-PI3K, PI3K, p-AKT, AKT, p-JNK, JNK, p-p38 and p38 were estimated by western blot analysis.

RESULTS

Sal alleviated CoCl2-induced hypoxic injury in HT22 cells as evidenced by increased cell viability and decreased LDH release. In vitro antioxidant test confirmed that Sal had marvelous antioxidant abilities. The protected mitochondrial function by Sal treatment was illustrated by the decrease of ROS, Ca2+, mitochondrial fragment and the increase of MMP. In addition, Sal ameliorated the apoptosis of HT22 cells by decreasing Hoechst 33342 positive cells and the rate of apoptotic cells. Enhancement of energy metabolism in HT22 by Sal was demonstrated by increased OCR, real-time ATP generation and proton efflux rate. The molecular docking confirmed the potential binding of Sal to PI3K, AKT and CaMK II proteins with calculated binding energy of -1.32, -4.21 and -4.38 kcal/mol, respectively. The MDS test revealed the average hydrogen bond of complex Sal-PI3K and Sal-AKT were 0.79 and 4.46, respectively. The results of LSPR verified the potential binding of Sal to proteins PI3K, AKT and HIF-1α with affinity values of 5.20 × 10 - 3, 2.83 × 10 - 3 and 3.97 × 10 - 3 KD, respectively. Western blot analysis further argued that Sal consolidated the levels of p-PI3K and p-AKT. Meanwhile, Sal could downregulate the proteins expression of p-JNK and p-p38.

CONCLUSION

Collectively, our findings suggested that Sal can intensify mitochondrial function of CoCl2-simulated hypoxia injury in HT22 cells by stimulating PI3K-AKT-MAPK signaling pathway. Sal is a potential agent for mitochondrial protection against hypoxia with the underlying molecular mechanisms of energy metabolism being further elucidated.

EGCG protects the mouse brain against cerebral ischemia/reperfusion injury by suppressing autophagy via the AKT/AMPK/mTOR phosphorylation pathway

Stroke remains one of the leading reasons of mortality and physical disability worldwide. The treatment of cerebral ischemic stroke faces challenges, partly due to a lack of effective treatments. In this study, we demonstrated that autophagy was stimulated by transient middle cerebral artery occlusion/reperfusion (MCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R). Treatment with (−)-epigallocatechin-3-gallate (EGCG), a bioactive ingredient in green tea, was able to mitigate cerebral ischemia/reperfusion injury (CIRI), given the evidence that EGCG administration could reduce the infarct volume and protect poststroke neuronal loss in MCAO/R mice in vivo and attenuate cell loss in OGD/R-challenged HT22 cells in vitro through suppressing autophagy activity. Mechanistically, EGCG inhibited autophagy via modulating the AKT/AMPK/mTOR phosphorylation pathway both in vivo and in vitro models of stroke, which was further confirmed by the results that the administration of GSK690693, an AKT/AMPK inhibitor, and rapamycin, an inhibitor of mTOR, reversed aforementioned changes in autophagy and AKT/AMPK/mTOR signaling pathway. Overall, the application of EGCG relieved CIRI by suppressing autophagy via the AKT/AMPK/mTOR phosphorylation pathway.

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.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.