CFTR prevents neuronal apoptosis following cerebral ischemia reperfusion via regulating mitochondrial oxidative stress

Ivacaftor attenuates gentamicin-induced ototoxicity through the CFTR-Nrf2-HO1/NQO1 pathway

OBJECTIVES

Gentamicin is one of the most common ototoxic drugs that can lower patients' quality of life. Oxidative stress is a key factors inducing sensory hair cell death during gentamicin administration. So far, there are no effective drugs to prevent or treat gentamicin- induced hearing loss. A recent study found cystic fibrosis transmembrane conductance regulator (CFTR) as a new target to modulate cellular oxidative balance. The objective of this study was to estimate the effect of the CFTR activator ivacaftor on gentamicin-induced ototoxicity and determine its mechanism.

METHODS

The hair cell count was analyzed by Myosin 7a staining. Apoptosis was analyzed by TUNEL Apoptosis Kit. Cellular reactive oxygen species (ROS) level was detected by DCFH-DA probes. The Nrf2 related proteins expression levels were analyzed by western blot.

RESULTS

An in vitro cochlear explant model showed that gentamicin caused ROS accumulation in sensory hair cells and induced apoptosis, and this effect was alleviated by pretreatment with ivacaftor. Western blotting showed that ivacaftor administration markedly increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO1), and NAD(P)H:quinone oxidoreductase 1 (NQO1). The protective effect of ivacaftor was abolished by the Nrf2 inhibitor ML385.

DISCUSSION

Our results indicate the protective role of the CFTR-Nrf2-HO1/NQO1 pathway in gentamicin-induced ototoxicity. Ivacaftor may be repositioned or repurposed towards aminoglycosides-induced hearing loss.

Differences in toxicity induced by the various polymer types of nanoplastics on HepG2 cells

The problem of microplastics (MPs) contamination in food has gradually come to the fore. MPs can be transmitted through the food chain and accumulate within various organisms, ultimately posing a threat to human health. The concentration of nanoplastics (NPs) exposed to humans may be higher than that of MPs. For the first time, we studied the differences in toxicity, and potential toxic effects of different polymer types of NPs, namely, polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (PS) on HepG2 cells. In this study, PET-NPs, PVC-NPs, and PS-NPs, which had similar particle size, surface charge, and shape, were prepared using nanoprecipitation and emulsion polymerization. The results of the CCK-8 assay showed that the PET-NPs and PVC-NPs induced a decrease in cell viability in a concentration-dependent manner, and their lowest concentrations causing significant cytotoxicity were 100 and 150 μg/mL, respectively. Moreover, the major cytotoxic effects of PET-NPs and PVC-NPs at high concentrations may be to induce an increase in intracellular ROS, which in turn induces cellular damage and other toxic effects. Notably, our study suggested that PET-NPs and PVC-NPs may induce apoptosis in HepG2 cells through the mitochondrial apoptotic pathway. However, no relevant cytotoxicity, oxidative damage, and apoptotic toxic effects were detected in HepG2 cells with exposure to PS-NPs. Furthermore, the analysis of transcriptomics data suggested that PET-NPs and PVC-NPs could significantly inhibit the expression of DNA repair-related genes in the p53 signaling pathway. Compared to PS-NPs, the expression levels of lipid metabolism-related genes were down-regulated to a greater extent by PET-NPs and PVC-NPs. In conclusion, PET-NPs and PVC-NPs were able to induce higher cytotoxic effects than PS-NPs, in which the density and chemical structure of NPs of different polymer types may be the key factors causing the differences in toxicity.

Neuritin has a neuroprotective role in the rat model of acute ischemia stroke by inhibiting neuronal apoptosis and NLRP3 inflammasome

OBJECTIVES

This study explored the anti-inflammatory, anti-neuronal apoptosis, and neuroprotective effects of Neuritin in rat models of acute ischemia stroke (AIS).

METHODS

AIS was induced in male Sprague Dawley rats by middle cerebral artery occlusion (MCAO). Rats were divided into sham, MCAO, MCAO+neuritin, MCAO + neuritin + PBS, MCAO + neuritin+MCC950, and MCAO + neuritin + MSU groups. Neurological score assessment, brain water content measurement, HE staining, TTC staining, TUNEL staining, ELISA, and Western blot were performed.

RESULTS

Neuritin significantly improved the neurobehavioral score, infarct size, brain water content, apoptosis, and neuroinflammatory response compared with the MCAO and MCAO + PBS groups within 24 h after AIS. Moreover, Neuritin inhibited the protein expression of NLRP3 inflammasome, and reduced the expression of IL-18 and IL-1B, thereby reducing the inflammatory response. Meanwhile, the neuroprotection, anti-inflammation, and anti-apoptosis effects of Neuritin were enhanced by MCC950 but partly counteracted by MSU.

CONCLUSION

Neuritin may reduce brain injury after AIS by inhibiting the expression of NLRP3 inflammasome and then inhibiting the inflammatory response.

PHLDA1 knockdown alleviates mitochondrial dysfunction and endoplasmic reticulum stress-induced neuronal apoptosis via activating PPARγ in cerebral ischemia-reperfusion injury

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress occur in ischemic stroke. The disruption of these two organelles can directly lead to cell death through various signaling pathways. Thus, investigation of the associated molecular mechanisms in cerebral ischemia is a prerequisite for stroke treatment. Pleckstrin homology-like domain family A member 1 (PHLDA1) is a multifunctional protein that can modulate mitochondrial function and ER stress in cardiomyocyte and cancer cells. This work studied the role of PHLDA1 in cerebral ischemic/reperfusion (I/R) injury and explored the underlying mechanisms associated with mitochondrial functions and ER stress. Middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated neurons were used as I/R models in vivo and in vitro, respectively. PHLDA1 was upregulated in ischemic penumbra of MCAO/R-induced mice and OGD/R-exposed neurons. In vitro, PHLDA1 knockdown protected neurons from OGD/R-induced apoptosis. In vivo, PHLDA1 silencing facilitated functional recovery and reduced cerebral infarct volume. Mechanistically, PHLDA1 knockdown promoted PPARγ nuclear translocation, which may mediate the effects on reversion of mitochondrial functions and alleviation of ER stress. In summary, PHLDA1 knockdown alleviates neuronal ischemic injuries in mice. PPARγ activation and mitochondrial dysfunction and endoplasmic reticulum stress attenuation are involved in the underlying mechanisms.

Cystic Fibrosis Transmembrane Conductance Regulator Attenuates Oxidative Stress-Induced Injury in Diabetic Retinopathy Rats

PURPOSE

To investigate the effects of cystic fibrosis transmembrane conductance regulator (CFTR) on oxidative stress-induced injury of diabetic retinopathy (DR) rats.

METHODS

DR rat model was constructed treated with Ad-CFTR. Hematoxylin and Eosin (HE) staining was applied for testing the thickness of each layer of retinal tissues. Enzyme-linked immunosorbent assay (ELISA) was used to determine levels of serum inflammatory cytokines and contents of oxidative stress related genes in rats. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining was used to detect retinal cell apoptosis, and western blotting to measure the expression of MAPK/NF-κB pathway-related proteins in retinal tissues.

RESULTS

Our experiment revealed the remarkable decrease of CFTR protein in retinal tissues of DR rats. DR rats had decreased body weight and increased blood glucose level, with decreased thickness of total retinal thickness (TRT), outer nuclear layer and outer plexiform layer (ONL + OPL), inner nuclear layer (INL), and inner plexiform layer (IPL). Besides, DR rats were apparently up-regulated in the expression of pro-inflammatory cytokines, with increased malondial dehyde (MDA), p-ERK1/2/ERK1/2 and p-JNK1/2/JNK1/2 expressions, decreased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in retinal tissues, as well as up-regulated p65 protein in nucleus and down-regulated p65 protein in cytoplasm. DR rats treated with Ad-CFTR were effectively improved regarding the above parameters except body weight and blood glucose.

CONCLUSIONS

CFTR can inhibit MAPK/NF-κB signaling pathway to ameliorate inflammatory response and oxidative stress-induced injury of DR rats, thereby reducing retinal cell apoptosis and playing a protective role in retina.

cPKCγ Inhibits Caspase-9-Initiated Neuronal Apoptosis in an Ischemia Reperfusion Model In Vitro Through p38 MAPK-p90RSK-Bad Pathway

Strokes are one of the leading causes of death and disability in the world. Previously we have found that conventional protein kinase Cγ (cPKCγ) plays neuroprotective role in ischemic strokes. Further, we found that cPKCγ knockdown increased the level of cleaved (cl)-Caspase-3. However, the precise mechanisms underlying cPKCγ-mediated neuronal death remain unclear. To this end, a model incorporating 1 h oxygen-glucose deprivation/24 h reoxygenation (1 h OGD/24 h R) was established in cortical neurons. We found that cPKCγ knockdown remarkably increased neuronal death after OGD. We also found that cPKCγ knockdown increased the level of cl-Caspase-3 through the upstream initiators Capsases-9 (not Caspase-8/12) in OGD-treated neurons. Overexpression of cPKCγ could decrease neuronal death and cl-Caspase-3 and -9 levels. Moreover, cPKCγ knockdown further reduced the phosphorylation levels of p38 MAPK, p90RSK, and Bad. In addition, the protein levels of Bcl-2 and Bcl-xl were decreased after cPKCγ knockdown, whereas that of Bax was increased. In conclusion, our results suggest that cPKCγ partly alleviates ischemic injury through activating the p38 MAPK-p90RSK-Bad pathway and inhibiting Caspase-9 initiated apoptosis. This may have potential as a therapeutic target for ischemic stroke.

PD98059 protects SH-SY5Y cells against oxidative stress in oxygen-glucose deprivation/reperfusion

Mitochondria play a key role in the cerebral ischemia-reperfusion injury. Although the extracellular signal-regulated kinase 1/2 inhibitor PD98059 (PD) is a selective and reversible flavonoid that can protect the mitochondria in a rat model of cardiac arrest/cardiopulmonary resuscitation, its role requires further confirmation. In this study, we investigated whether PD could maintain mitochondrial homeostasis and decrease reactive oxygen species (ROS) production in neuroblastoma (SH-SY5Y) cells exposed to oxygen-glucose deprivation/reperfusion (OGD/R). PD improved the mitochondrial morphology and function, reversed the increase in ROS production and cell apoptosis, and reduced total-superoxide dismutase and Mn-superoxide dismutase activities induced by OGD/R. PD decreases ROS production and improves mitochondrial morphology and function, protecting SH-SY5Y cells against OGD/R-induced injury.

Restoring myocardial infarction-induced long-term memory impairment by targeting the cystic fibrosis transmembrane regulator

BACKGROUND

Cognitive impairment is a serious comorbidity in heart failure patients, but effective therapies are lacking. We investigated the mechanisms that alter hippocampal neurons following myocardial infarction (MI).

METHODS

MI was induced in male C57Bl/6 mice by left anterior descending coronary artery ligation. We utilised standard procedures to measure cystic fibrosis transmembrane regulator (CFTR) protein levels, inflammatory mediator expression, neuronal structure, and hippocampal memory. Using in vitro and in vivo approaches, we assessed the role of neuroinflammation in hippocampal neuron degradation and the therapeutic potential of CFTR correction as an intervention.

FINDINGS

Hippocampal dendrite length and spine density are reduced after MI, effects that associate with decreased neuronal CFTR expression and concomitant microglia activation and inflammatory cytokine expression. Conditioned medium from lipopolysaccharide-stimulated microglia (LCM) reduces neuronal cell CFTR protein expression and the mRNA expression of the synaptic regulator post-synaptic density protein 95 (PSD-95) in vitro. Blocking CFTR activity also down-regulates PSD-95 in neurons, indicating a relationship between CFTR expression and neuronal health. Pharmacologically correcting CFTR expression in vitro rescues the LCM-mediated down-regulation of PSD-95. In vivo, pharmacologically increasing hippocampal neuron CFTR expression improves MI-associated alterations in neuronal arborisation, spine density, and memory function, with a wide therapeutic time window.

INTERPRETATION

Our results indicate that CFTR therapeutics improve inflammation-induced alterations in hippocampal neuronal structure and attenuate memory dysfunction following MI.

FUNDING

Knut and Alice Wallenberg Foundation [F 2015/2112]; Swedish Research Council [VR; 2017-01243]; the German Research Foundation [DFG; ME 4667/2-1]; Hjärnfonden [FO2021-0112]; The Crafoord Foundation; Åke Wibergs Stiftelse [M19-0380], NMMP 2021 [V2021-2102]; the Albert Påhlsson Research Foundation; STINT [MG19-8469], Lund University; Canadian Institutes of Health Research [PJT-153269] and a Heart and Stroke Foundation of Ontario Mid-Career Investigator Award.

Pinus massoniana needle extracts attenuate oxidative stress injury in cerebral ischemia reperfusion rats by regulating JNK3/caspase-3 signal transduction

OBJECTIVE

To investigate the effect and mechanism of Pinus massoniana needle extracts (PNE) on oxidative stress injury in cerebral ischemia reperfusion rats.

METHODS

The SD male rats were randomly divided into sham group, model control group, Edaravone (3 mg/kg) group, PNE low-dose (200 mg/kg), medium-dose (400 mg/kg) and high-dose (800 mg/kg) groups. PNE was administered by gavage for 7 d before modeling and 6 h after modeling in PNE treatment groups; Edaravone was given by intraperitoneal injection 7 d before modeling and 6 h after reperfusion. The rat model of cerebral ischemia reperfusion injury was established by middle cerebral artery occlusion method. After 24 h of reperfusion, the neurological deficit score, brain water content and cerebral infarction volume of rats were measured. The pathological changes of cerebral cortex and hippocampus were observed by HE staining, and the number of normal nerve cells was counted. The apoptosis rate of neurons in cerebral cortex was detected by TUNEL method. The content of nitric oxide (NO), malondialdehyde (MDA) and superoxide dismutase (SOD) activity in ischemic brain tissue were detected. The protein expression of c-Jun N-terminal kinase (JNK) 3, phosphorylated JNK3 (p-JNK3), B-cell lymphoma protein(Bcl) -2, Bcl-2 associated X (Bax), cytochrome C and caspase-3 in cerebral cortex were detected by Western blotting method.

RESULTS

Compared with the model control group, the behavioral score, brain water content and cerebral infarction volume in PNE groups were significantly reduced (all P<0.05), the pathological damage of cerebral cortex and hippocampal CA1 area was significantly alleviated, and the number of normal nerve cells in ischemic cortex and hippocampal CA1 area was increased (all P<0.05). The medium-dose PNE group had the best effect. Compared with the model control group, the apoptosis rate of cortical neurons, the content of NO and MDA in cerebral cortex, the ratio of p-JNK3/JNK3, the expression level of cytochrome C and caspase-3 protein in PNE medium-dose group were significantly reduced , and the activity of SOD, the Bcl-2/Bax ratio were significantly improved (all P<0.05).

CONCLUSION

PNE ameliorates brain injury after cerebral ischemia reperfusion in rats, which may be related to scavenging NO and MDA, inhibiting oxidative stress-mediated JNK3/caspase-3 signsal transduction to inhibit neuronal apoptosis.

Mitochondrial ferritin alleviates apoptosis by enhancing mitochondrial bioenergetics and stimulating glucose metabolism in cerebral ischemia reperfusion

Oxidative stress and deficient bioenergetics are key players in the pathological process of cerebral ischemia reperfusion injury (I/R). As a mitochondrial iron storage protein, mitochondrial ferritin (FtMt) plays a pivotal role in protecting neuronal cells from oxidative damage under stress conditions. However, the effects of FtMt in mitochondrial function and activation of apoptosis under cerebral I/R are barely understood. In the present study, we found that FtMt deficiency exacerbates neuronal apoptosis via classical mitochondria-depedent pathway and the endoplasmic reticulum (ER) stress pathway in brains exposed to I/R. Conversely, FtMt overexpression significantly inhibited oxygen and glucose deprivation and reperfusion (OGD/R)-induced apoptosis and the activation of ER stress response. Meanwhile, FtMt overexpression rescued OGD/R-induced mitochondrial iron overload, mitochondrial dysfunction, the generation of reactive oxygen species (ROS) and increased neuronal GSH content. Using the Seahorse and O2K cellular respiration analyser, we demonstrated that FtMt remarkably improved the ATP content and the spare respiratory capacity under I/R conditions. Importantly, we found that glucose consumption was augmented in FtMt overexpressing cells after OGD/R insult; overexpression of FtMt facilitated the activation of glucose 6-phosphate dehydrogenase and the production of NADPH in cells after OGD/R, indicating that the pentose-phosphate pathway is enhanced in FtMt overexpressing cells, thus strengthening the antioxidant capacity of neuronal cells. In summary, our results reveal that FtMt protects against I/R-induced apoptosis through enhancing mitochondrial bioenergetics and regulating glucose metabolism via the pentose-phosphate pathway, thus preventing ROS overproduction, and preserving energy metabolism.

Cystic fibrosis transmembrane conductance regulator prevents ischemia/reperfusion induced intestinal apoptosis via inhibiting PI3K/AKT/NF-κB pathway

BACKGROUND

Intestinal ischemia/reperfusion (I/R) injury is a fatal syndrome that occurs under many clinical scenarios. The apoptosis of intestinal cells caused by ischemia can cause cell damage and provoke systemic dysfunction during reperfusion. However, the mechanism of I/R-induced apoptosis remains unclear. Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel. Few researchers have paid attention to its role in intestinal I/R injury, or the relationship between CFTR and intestinal apoptosis induced by hypoxia/reoxygenation (H/R).

AIM

To investigate the effects of CFTR on I/R-induced intestinal apoptosis and its underlying molecular mechanisms.

METHODS

An intestinal I/R injury model was established in mice with superior mesenteric artery occlusion, and Caco2 cells were subjected to H/R for the simulation of I/R in vivo.

RESULTS

The results suggested that CFTR overexpression significantly increased the Caco2 cell viability and decreased cell apoptosis induced by the H/R. Interestingly, we found that the translocation of p65, an NF-κB member, from the cytoplasm to the nucleus after H/R treatment can be reversed by the overexpression of CFTR, the NF-κB P65 would return from the nucleus to the cytoplasm as determined by immunostaining. We also discovered that CFTR inhibited cell apoptosis in the H/R-treated cells, and this effect was significantly curbed by the NF-κB activator BA, AKT inhibitor GSK690693 and the PI3K inhibitor LY294002. Moreover, we demonstrated that CFTR overexpression could reverse the decreased PI3K/AKT expression induced by the I/R treatment in vivo or H/R treatment in vitro.

CONCLUSION

The results of the present study indicate that the overexpression of CFTR protects Caco2 cells from H/R-induced apoptosis; furthermore, it also inhibits H/R-induced apoptosis through the PI3K/AKT/NF-κB signaling pathway in H/R-treated Caco2 cells and intestinal tissues.

Microplastic-induced apoptosis and metabolism responses in marine Dinoflagellate, Karenia mikimotoi

Microplastics (MPs) occur widely in marine environments, and disturb the balance of aquatic ecosystems. In this study, programmed cell apoptosis in marine dinoflagellate, Karenia mikimotoi exposed to 10 mg L^-1 micro/nanoplastics (MPs/NPs; polystyrene and polymethyl methacrylate) for 72 h was assessed. Prior to the toxicity assay, MPs/NPs were dialyzed to remove possible additives. Cell viability, membrane integrity, cell apoptosis, and total DNA concentration were measured to assess programmed cell apoptosis in K. mikimotoi following exposure to MPs/NPs. A transcriptome analysis was used to explore the potential toxic mechanism of MPs to K. mikimotoi. Programmed cell apoptosis was related to the size of MPs/NPs, and NPs could more easily impair cell viability, and reduced cell membrane integrity and DNA concentration. NP particles caused continuous apoptosis of K. mikimotoi compared to MP particles. Size had the greatest effect on toxicity in K. mikimotoi. In conclusion, the results evidenced that both MPs and NPs have a negative impact on the marine dinoflagellate, K. mikimotoi. However, NPs were more harmful to K mikimotoi than MPs, highlighting the potential ecological problems associated with exposure to NPs.

The Distribution and Role of the CFTR Protein in the Intracellular Compartments

Cystic fibrosis is a hereditary disease that mainly affects secretory organs in humans. It is caused by mutations in the gene encoding CFTR with the most common phenylalanine deletion at position 508. CFTR is an anion channel mainly conducting Cl⁻ across the apical membranes of many different epithelial cells, the impairment of which causes dysregulation of epithelial fluid secretion and thickening of the mucus. This, in turn, leads to the dysfunction of organs such as the lungs, pancreas, kidney and liver. The CFTR protein is mainly localized in the plasma membrane; however, there is a growing body of evidence that it is also present in the intracellular organelles such as the endosomes, lysosomes, phagosomes and mitochondria. Dysfunction of the CFTR protein affects not only the ion transport across the epithelial tissues, but also has an impact on the proper functioning of the intracellular compartments. The review aims to provide a summary of the present state of knowledge regarding CFTR localization and function in intracellular compartments, the physiological role of this localization and the consequences of protein dysfunction at cellular, epithelial and organ levels. An in-depth understanding of intracellular processes involved in CFTR impairment may reveal novel opportunities in pharmacological agents of cystic fibrosis.

Baicalin Inhibits NLRP3 Inflammasome Activity Via the AMPK Signaling Pathway to Alleviate Cerebral Ischemia-Reperfusion Injury

Baicalin has been reported to have ameliorative effects on nerve-induced hypoxic ischemia injury; however, its role in the NLRP3 inflammasome-dependent inflammatory response during cerebral ischemia-reperfusion remains unclear. To investigate the molecular mechanisms involved in baicalin alleviating cerebral ischemia-reperfusion injury, we investigated the AMPK signaling pathway which regulates NLRP3 inflammasome activity. SD rats were treated with baicalin at doses of 100 mg/kg and 200 mg/kg, respectively, after middle cerebral artery occlusion at 2 h and reperfusion for 24 h (MCAO/R). MCAO/R treatment significantly increased cerebral infarct volume, changed the ultrastructure of nerve cells, and activated the NLRP3 inflammasome, manifesting as significantly increased expression of NLRP3, ASC, cleaved caspase-1, IL-1β, and IL-18. Our results demonstrated that baicalin treatment effectively reversed these phenomena in a dose-dependent manner. Additionally, inhibition of NLRP3 expression was found to promote the neuroprotective effects of baicalin on cortical neurons. Furthermore, baicalin remarkably increased the expression of p-AMPK following oxygen glucose deprivation/reperfusion (OGD/R). The expression of the NLRP3 inflammasome was also increased when the AMPK pathway was blocked by compound C. Taken together, our findings reveal that baicalin reduces the activity of the NLRP3 inflammasome and consequently inhibits cerebral ischemia-reperfusion injury through activation of the AMPK signaling pathway.

Imaging Mitochondrial Hydrogen Peroxide in Living Cells

Hydrogen peroxide (H₂O₂) produced from mitochondria is intimately involved in human health and disease, but is challenging to selectively monitor inside living systems. The fluorescent probe MitoPY1 provides a practical tool for imaging mitochondrial H₂O₂ and has been demonstrated to function in a variety of diverse cell types. In this chapter, we describe the synthetic preparation of the small molecule probe MitoPY1 , methods for validating this probe in vitro and in live cells, and an example procedure for measuring mitochondrial H₂O₂ in a cell culture model of Parkinson's disease.

MicroRNA-145 plays a role in mitochondrial dysfunction in alveolar epithelial cells in lipopolysaccharide-induced acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) causes substantial mortalities. Alveolar epithelium is one of the main sites of cell injuries in ARDS. As an important kind of microRNAs (miRNAs), microRNA-145 (miR-145) has been studied in various diseases, while its role in ARDS has not been investigated.

METHODS

Lipopolysaccharide (LPS) was intratracheally instilled to establish a rat ARDS model. Cytokines from bronchoalveolar lavage fluid (BALF) were measured using rat tumor necrosis factor-α and interleukin-6 enzyme-linked immunosorbent assay kits (R&D Systems), and the pathological structures were evaluated using hematoxylin and eosin (H&E) staining and transmission electron microscope; the lung miR-145 messenger RNA (mRNA) was detected using quantitative polymerase chain reaction. Bioinformatics focused on the target genes and possible pathways of gene regulation.

RESULTS

A rat model of LPS-induced ARDS was successfully established. The miR-145 was down-regulated in the LPS-induced ARDS lung, and mitochondrial dysfunction was observed in alveolar epithelial cells, most obviously at 72 hours after LPS. TargetScan and miRDB databases were used to predict the target genes of miR-145. A total of 428 overlapping genes were identified, seven genes were associated with mitochondrial function, and Ogt, Camk2d, Slc8a3, and Slc25a25 were verified. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, and Gene Ontology (GO) biological process was mainly enriched in signal transduction and transcription regulation.

CONCLUSIONS

The miR-145 is down-regulated in LPS-induced ARDS, and affects its downstream genes targeting mitochondrial functions.

In vitro cultured calculus bovis attenuates cerebral ischaemia-reperfusion injury by inhibiting neuronal apoptosis and protecting mitochondrial function in rats

ETHNOPHARMACOLOGICAL RELEVANCE

In vitro cultured calculus bovis (ICCB), which is produced based on the formation mechanism of bovine gallstones, is used to replace the natural bezoar. It has been used in the clinic to treat brain diseases, including stroke, Alzheimer's disease and depression.

AIM OF STUDY

ICCB is used to treat encephalopathy in the clinic. We explored the effects of ICCB on cerebral ischaemia-reperfusion injury (CIRI) and the potential associated mechanisms.

MATERIALS AND METHODS

Rats were subjected to middle cerebral artery occlusion for 90 min, followed by 24 h of reperfusion, after being given different concentrations of ICCB once a day for 3 days. Subsequently, the neurological scores, brain oedema and volume of cerebral infarction were measured, and the histopathological changes in the cortex neurons were observed by haematoxylin and eosin staining (H&E). Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL). Ultrastructural changes in the mitochondria of the cortex were assessed by transmission electron microscopy (TEM). The apoptosis-related proteins Bax, Bcl-2, caspase-9, caspase-3, Mito-Cyt C and Cyto-Cyt C were detected by Western blotting.

RESULTS

Compared with those in the control group, the neurological scores, the volumes of cerebral infarction, and the brain water contents were significantly decreased in the ICCB groups at doses of 50 and 100 mg/kg. The ICCB treatment effectively decreased the neuronal apoptosis resulting from the CIRI-induced neuron injury. In addition, the histopathological damage and the mitochondria ultrastructure injury were partially improved in the CIRI rats after ICCB treatment. Western blotting analysis indicated that ICCB significantly decreased the expression of Bax, caspase-9, caspase-3 and Cyto-Cyt C protein levels while increasing the expression of Bcl-2 and Mito-Cyt C protein levels.

CONCLUSION

The ICCB protected against CIRI by suppressing the mitochondria-mediated apoptotic signalling pathway.

A novel biscoumarin derivative dephosphorylates ERK and alleviates apoptosis induced by mitochondrial oxidative damage in ischemic stroke mice

AIM

We previously reported the protective effects of biscoumarin derivatives against oxidative stress, but effects of the derivative on mitochondrial oxidative damage induced apoptosis in ischemic stroke remains unknown.

METHODS

Primary neurons were subjected to oxygen and glucose deprivation (OGD) for the in vitro simulation of ischemic stroke, and an ischemic stroke model was established in mice by operation of middle cerebral artery occlusion (MCAO).

RESULTS

The results indicated that the nontoxic concentration range of biscoumarin derivative Comp. B in neurons was from 0 to 30 μg/ml and the optimal protective concentration was 20 μg/ml. Treatment with Comp. B increased the cell survival rate and alleviated mitochondrial oxidative damage and apoptosis in OGD-treated neurons. Comp. B reduced the ratio of Bax/Bcl-2, inhibited the phosphorylation of ERK, and thus alleviated apoptosis in OGD-treated neurons. Further research demonstrated that the dephosphorylation effect on ERK of Comp. B is a key factor in alleviating apoptosis in neurons induced by OGD injury. Furthermore, Comp. B reduced the infarct volume, improved neurobehavioural score, and alleviated morphological changes and brain apoptosis in MCAO mice.

CONCLUSION

The novel biscoumarin derivative Comp. B alleviates mitochondrial oxidative damage and apoptosis in ischemic stroke mice. These findings might provide new insights that will aid in elucidating the effect of biscoumarin derivative against cerebral ischemic reperfusion injury and support the new development of Comp. B as a potential treatment for ischemic stroke.

Drug development in targeting ion channels for brain edema

Cerebral edema is a pathological hallmark of various central nervous system (CNS) insults, including traumatic brain injury (TBI) and excitotoxic injury such as stroke. Due to the rigidity of the skull, edema-induced increase of intracranial fluid significantly complicates severe CNS injuries by raising intracranial pressure and compromising perfusion. Mortality due to cerebral edema is high. With mortality rates up to 80% in severe cases of stroke, it is the leading cause of death within the first week. Similarly, cerebral edema is devastating for patients of TBI, accounting for up to 50% mortality. Currently, the available treatments for cerebral edema include hypothermia, osmotherapy, and surgery. However, these treatments only address the symptoms and often elicit adverse side effects, potentially in part due to non-specificity. There is an urgent need to identify effective pharmacological treatments for cerebral edema. Currently, ion channels represent the third-largest target class for drug development, but their roles in cerebral edema remain ill-defined. The present review aims to provide an overview of the proposed roles of ion channels and transporters (including aquaporins, SUR1-TRPM4, chloride channels, glucose transporters, and proton-sensitive channels) in mediating cerebral edema in acute ischemic stroke and TBI. We also focus on the pharmacological inhibitors for each target and potential therapeutic strategies that may be further pursued for the treatment of cerebral edema.

Potential role of CFTR in bisphenol A-induced malignant transformation of prostate cells via mitochondrial apoptosis

Bisphenol A (BPA) is an environmental endocrine disruptor and a risk factor for prostate cancer. The cystic fibrosis transmembrane conductance regulator (CFTR) is proposed to be a prostate cancer suppressor in some recent researches. However, the potential role and mechanism of CFTR in BPA-induced prostate cancer cells has not been well identified. In this study, BPA decreased the viability of human normal prostate RWPE-1 cells detected with a CCK-8 kit. The capacity of the cell line on soft agar colony formation, wound healing, and transwell invasion indicated malignant transformation induced by BPA. Western blot analysis demonstrated that the levels of CFTR and Bcl-2 decreased, whereas Bax level increased, and ELISA detection showed a decreased ATP level in BPA-exposed cells. Cell apoptosis was analyzed with Annexin V-FITC Detection Kit by flow cytometry. However, no significant difference was observed in cell viability and apoptosis rates compared to normal RWPE-1 cells. Our research revealed a potential role of CFTR in BPA-induced malignant transformation via mitochondrial apoptosis of normal prostate cells.

Remote Ischemic Postconditioning Inhibits Hippocampal Neuronal Apoptosis and Mitophagy After Cardiopulmonary Resuscitation in Rats

BACKGROUND

Studies have shown that remote ischemic post-conditioning can improve brain damage caused by ischemia and hypoxia. However, the specific mechanism underlying this phenomenon is still unclear. The purpose of this study was to investigate the effects of remote ischemic post-conditioning on neuronal apoptosis and mitophagy after cardiopulmonary resuscitation (CPR) in rats.

METHODS

Male Sprague-Dawley rats were used to establish an asphyxia cardiac arrest model by clamping the tracheal duct. First, the expression levels of P53, Cytochrome c (Cytc), and Parkin in the cytoplasm and mitochondria were observed at 3, 6, 24, and 72 h after the restoration of spontaneous circulation (ROSC). Then neurological deficit scores, hippocampal neuron apoptosis, mitochondrial P53 and Parkin, cytoplasmic Cytc, and neuron ultrastructure were evaluated 24 h after ROSC.

RESULTS

P53 and Parkin can translocate from the cytoplasm to the mitochondria, promoting the translocation of cytoplasmic Cytc to mitochondria after CPR, reaching a peak at 24 h after the ROSC. The P53 inhibitor Pifithrin-μ reduced apoptosis induced by P53 mitochondrial translocation. Apoptosis was induced after cardiac arrest and attenuated by remote ischemic postconditioning via inhibiting P53 mitochondrial translocation and the release of Cytc to the cytoplasm. In addition, remote ischemic postconditioning could inhibit Parkin-mediated mitophagy.

CONCLUSION

Taken together, our results show that remote ischemic post-conditioning improves neural function after CPR by inhibiting P53 mitochondrial translocation-induced apoptosis and Parkin-mediated mitophagy.

Adiponectin inhibits cardiac arrest/cardiopulmonary resuscitation‑induced apoptosis in brain by increasing autophagy involved in AdipoR1‑AMPK signaling

Emerging evidence suggests that both apoptosis and autophagy contribute to global cerebral ischemia‑reperfusion (GCIR)‑induced neuronal death, which results from cardiac arrest (CA). However, the mechanism of how GCIR may affect the balance between apoptosis and autophagy resulting from CA remains to be elucidated. Additionally, the role of adiponectin (APN) in reversing the apoptosis and autophagy induced by GCIR following cardiac arrest‑cardiopulmonary resuscitation (CA‑CPR) is unclear. Thus, the aim of the present study was to investigate how GCIR affect the apoptosis and autophagy in response to CA and to clarify whether APN may alter the apoptosis and autophagy of neuronal death in GCIR‑injured brain post‑CA‑CPR. Using normal controls (Sham group) and two experimental groups [CA‑CPR‑induced GCIR injury (PCAS) group and exogenous treatment with adiponectin post‑CA‑CPR (APN group)], it was demonstrated that both apoptosis and autophagy were observed simultaneously in the brain subjected to GCIR, but apoptosis appeared to be more apparent. Exogenous administration of APN significantly reduced the formation of malondialdehyde, a marker of oxidative stress and increased the expression of superoxide dismutase, an anti‑oxidative enzyme, resulting in the stimulation of autophagy, inhibition of apoptosis and reduced brain tissue injury (P<0.05 vs. PCAS). APN treatment increased the expression of APN receptor 1 (AdipR1) and the phosphorylation of AMP‑activated protein kinase (AMPK; Ser182) in brain tissues. In conclusion, GCIR induced apoptosis and inhibited autophagy, contributing to brain injury in CA‑CPR. By contrast, APN reduced the brain injury by reversing the changes of neuronal autophagy and apoptosis induced by GCIR. The possible mechanism might owe to its effects on the activation of AMPK after combining with AdipR1 on neurons, which suggests a novel intervention against GCIR injury in CA‑CPR conditions.

Tea Polysaccharide (TPS) Reduces Astrocytes Apoptosis Induced by Oxygen-Glucose Deprivation/Reoxygenation by Regulating the miR-375/SRXN1 Axis

Objective. To investigate the effect of tea polysaccharides (TPS) mediated by miR-375/SRXN1 axis on mice with cerebral ischemia-reperfusion injury and proliferation and apoptosis of astrocytes (AS) conducted with oxygen-glucose deprivation/reoxygenation (OGD/R). Methods. Mouse model of middle cerebral artery occlusion (MCAO) and OGD/R-induced AS injury model were established; brain obstruction volume was measured by TTC staining; dry/wet weight ratio was used for measuring brain water content; hydrogen peroxide (H2O2) content in brain tissue was measured by H2O2 assay kit; cell viability and apoptosis rate were detected by MTT assay and flow cytometry, respectively; the expression level of miR-375 in OGD/R-AS was detected using qPCR; dual-luciferase reporter assay was used to verify the targeting relationship between miR-375 and SRXN1; mRNA levels of miR-375, SRXN1, Bcl-2, Bax, and caspase-3 were measured by qPCR; the protein levels of SRXN1, Bcl-2, Bax, and caspase-3 were measured by Western blotting. Results. The volume of cerebral obstruction, brain water content and H2O2 content in mice decreased gradually with the increase of TPS concentration. TPS treatment in vitro could effectively improve OGD/R-AS viability and reduce the apoptotic rate; overexpression of miR-375 inhibited AS viability but increased the apoptotic rate; TPS treatment resulted in a decrease in the expression of miR-375 in OGD/R-AS; MiR-375 targeted SRXN1 in AS; inhibition of miR-375 expression significantly upregulated SRXN1 levels; TPS treatment with simultaneous overexpression of SRXN1 significantly increased OGD/R-AS activity and reduced apoptosis; however, TPS treatment with simultaneous overexpression of SRXN1 and miR-375 resulted in no significant difference in cell viability and apoptosis rate compared with the control group. Conclusion. TPS reduces astrocyte injury induced by cerebral ischemia-reperfusion in mice by regulating the miR-375/SRXN1 molecular axis.

NMMHC IIA Inhibition Ameliorates Cerebral Ischemic/Reperfusion-Induced Neuronal Apoptosis Through Caspase-3/ROCK1/MLC Pathway

Purpose

Our previous studies have indicated that non-muscle myosin heavy chain IIA (NMMHC IIA) is involved in H₂O₂-induced neuronal apoptosis, which is associated with the positive feedback loop of caspase-3/ROCK1/MLC pathway. However, the neuroprotective effect of NMMHC IIA inhibition with an adeno-associated virus (AAV) vector after transient middle cerebral artery occlusion (MCAO) and its role in caspases-3/ROCK1/MLC pathway remain blurred.

Methods

Green fluorescent protein (GFP) and a small hairpin RNA targeting Myh9 (encoding NMMHC IIA) were cloned and packaged into the AAV9 vector. AAV-shMyh9 or control vector were injected into C57BL/6J mice four weeks prior to 60 min MCAO. Twenty-four hours after reperfusion, functional and histological analyses of the mice were performed.

Results

In this study, AAV-shMyh9 was used to down-regulate NMMHC IIA expression in mice. We found that down-regulation of NMMHC IIA could improve neurological scores and histological injury in ischemic mice. Ischemic attack also activated neuronal apoptosis, and this effect was partially attenuated when NMMHC IIA was inhibited by AAV-shMyh9. In addition, AAV-shMyh9 significantly reduced cerebral ischemic/reperfusion (I/R)-induced NMMHC IIA-actin interaction, caspase-3 cleavage, Rho-associated kinase1 (ROCK1) activation and myosin light-chains (MLC) phosphorylation.

Conclusion

Consequently, we showed that AAV-shMyh9 inhibits I/R-induced neuronal apoptosis linked with caspase-3/ROCK1/MLC/NMMHC IIA-actin cascade, which has also been confirmed to be a positive feedback loop. These findings put some insights into the neuroprotective effect of AAV-shMyh9 associated with the regulation of NMMHC IIA-related pathway under ischemic attack and provide a therapeutic strategy for ischemic stroke.

Noise-induced loss of sensory hair cells is mediated by ROS/AMPKα pathway

The formation of reactive oxygen species (ROS) is a well-documented process in noise-induced hearing loss (NIHL). We have also previously shown that activation of 5' adenosine monophosphate (AMP)-activated protein kinase (AMPKα) at its catalytic residue T172 is one of the key reactions triggering noise-induced outer hair cell (OHC) death. In this study, we are addressing the link between ROS formation and activation of AMPKα in OHCs after noise exposure. In-vivo treatment of CBA/J mice with the antioxidant N-acetyl cysteine (NAC) reduced noise-induced ROS formation (as assessed by the relative levels of 4-hydroxynonenal and 3-nitrotyrosine) and activation of AMPKα in OHCs. Forskolin, an activator of adenylyl cyclase (AC) and an antioxidant, significantly increased cyclic adenosine monophosphate (cAMP) and decreased ROS formation and noise-induced activation of AMPKα. Consequently, treatment with forskolin attenuated noise-induced losses of OHCs and NIHL. In HEI-OC1 cells, H₂O₂-induced activation of AMPKα and cell death were inhibited by the application of forskolin. The sum of our data indicates that noise activates AMPKα in OHCs through formation of ROS and that noise-exposure-induced OHC death is mediated by a ROS/AMPKα-dependent pathway. Forskolin may serve as a potential compound for prevention of NIHL.

CNS imaging studies in cystic fibrosis patients presenting with sudden neurological events

Background

Acute neurological events may present as an extrapulmonary complication in patients with cystic fibrosis (CF). These events can be secondary to a range of different aetiologies.

Methods

A retrospective analysis of 476 medical records of CF patients attending a large teaching hospital between 2000 and 2018 was performed. Patients presenting with acute neurological events who had MRI brain imaging were evaluated. Patients who had headaches without associated neurological symptoms were excluded from this analysis.

Results

Acute neurological presentations, excluding headaches without associated neurological symptoms, were reported in 27 index patients out of the 476 patients. Of these, 16 patients had MRI brain imaging for review. Three patients suffered pathology secondary to vascular events, both ischaemic and haemorrhagic; four patients had evidence of ischaemia or infarction not consistent with a vascular territory stroke and the remaining patients experienced a range of different neurological events. The most common presentation among these patients was seizure activity, followed by a transient motor or sensory deficit.

Conclusions

Neurological complications are recognised among individuals with CF. Although rare, they can be secondary to a range of different aetiologies, including dysfunctional cell energetics. Additional studies are required to further evaluate this association.