Neuroprotective effects of takinib on an experimental traumatic brain injury rat model via inhibition of transforming growth factor beta-activated kinase 1.

Transforming growth factor ß-activated kinase 1 (TAK1) plays a significant role in controlling several signaling pathways involved with regulating inflammation and apoptosis. As such, it represents an important potential target for developing treatments for traumatic brain injury (TBI). Takinib, a small molecule and selective TAK1 inhibitor, has potent anti-inflammatory activity and has shown promising activity in preclinical studies using rat models to evaluate the potential neuroprotective impact on TBI. The current study used a modified Feeney's weight-drop model to cause TBI in mature Sprague-Dawley male rats. At 30 min post-induction of TBI in the rats, they received an intracerebroventricular (ICV) injection of Takinib followed by assessment of their histopathology and behavior. The results of this study demonstrated how Takinib suppressed TBI progression in the rats by decreasing TAK1, p-TAK1, and nuclear p65 levels while upregulating IκB-α expression. Takinib was also shown to significantly inhibit the production of two pro-inflammatory factors, namely tumor necrosis factor-α and interleukin-1ß. Furthermore, Takinib greatly upregulated the expression of tight junction proteins zonula occludens-1 and claudin-5, reducing cerebral edema. Additionally, Takinib effectively suppressed apoptosis via downregulation of cleaved caspase 3 and Bax and reduction of TUNEL-positive stained cell count. As a result, an enhancement of neuronal function and survival was observed post-TBI. These findings highlight the medicinal value of Takinib in the management of TBI and offer an experimental justification for further investigation of TAK1 as a potential pharmacological target.

Identification of prognostic biomarkers for cervical cancer based on programmed cell death-related genes and assessment of their immune profile and response to drug therapy.

BACKGROUND: Programmed cell death (PCD) has been widely investigated in various human diseases. The present study aimed to identify a novel PCD-related genetic signature in cervical squamous cell carcinoma (CESC) to provide clues for survival, immunotherapy and drug sensitization prediction. METHODS: Single-sample gene set enrichment analysis (ssGSEA) was used to quantify the PCD score and assess the distribution of PCD in clinicopathological characteristics in The Cancer Genome Atlas (TCGA)-CESC samples. Then, the ConsensusClusterPlus method was used to identify molecular subtypes in the TCGA-CESC database. Genomic mutation analysis, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment, as well as tumor microenvironment (TME) infiltration analysis, were performed for each molecular subtype group. Finally, a prognostic model by Uni-Cox and least absolute shrinkage and selection operator-Cox analysis was established based on differentially expressed genes from molecular subtypes. ESTIMATE (i.e. Estimation of STromal and Immune cells in MAlignantTumours using Expression data) and ssGSEA were performed to assess the correlation between the model and TME. Drug sensitization prediction was carried out with the oncoPredict package. RESULTS: Preliminary analysis indicated that PCD had a potential association clinical characteristics of the TCGA-CESC cohort, and PCD-related genes mutated in 289 (70.59%) CESC patients. Next, four groups of CESC molecular typing were clustered based on 63 significantly prognostic PCD-related genes. Among four subtypes, C1 group displayed the worst prognosis combined with over expressed PCD genes and enriched cell cycle-related pathways. C4 group exhibited the best prognosis accompanied with high degree of immune infiltration. Finally, a five-gene (SERPINE1, TNF, CA9, CX3CL1 and JAK3) prognostic model was constructed. Patients in the high-risk group displayed unfavorable survival. Immune infiltration analysis found that the low-risk group had significantly higher levels of immune cell infiltration such as T cells, Macrophages_M1, relative to the high-risk group, and were significantly enriched in apoptosis-associated pathways, which predicted a higher level of immunity. Drug sensitivity correlation analysis revealed that the high-risk group was resistant to conventional chemotherapeutic drugs and sensitive to the Food and Drug Administration-approved drugs BI.2536_1086 and SCH772984_1564. CONCLUSIONS: In the present study, we first found that PCD-related gene expression patterns were correlated with clinical features of CESC patients, which predicts the feasibility of subsequent mining of prognostic features based on these genes. The five-PCD-associated-gene prognostic model showed good assessment ability in predicting patient prognosis, immune response and drug-sensitive response, and provided guidance for the elucidation of the mechanism by which PCD affects CESC, as well as for the clinical targeting of drugs.

NCOA4 requires a [3Fe-4S] to sense and maintain the iron homeostasis.

NCOA4 is a selective cargo receptor for ferritinophagy, the autophagic turnover of ferritin (FTH), a process critical for regulating intracellular iron bioavailability. However, how ferritinophagy flux is controlled through NCOA4 in iron-dependent processes needs to be better understood. Here, we show that the C-terminal FTH-binding domain of NCOA4 harbors a [3Fe-4S]-binding site with a stoichiometry of approximately one labile [3Fe-4S] cluster per NCOA4 monomer. By analyzing the interaction between NCOA4 and HERC2 ubiquitin ligase or NCOA4 and FTH, we demonstrate that NCOA4 regulates ferritinophagy by sensing the intracellular iron-sulfur cluster levels. Under iron-repletion conditions, HERC2 recognizes and recruits holo-NCOA4 as a substrate for polyubiquitination and degradation, favoring ferritin iron storage. Under iron-depletion conditions, NCOA4 exists in the form of apo-protein and binds ferritin to promote the occurrence of ferritinophagy and release iron. Thus, we identify an iron-sulfur cluster [3Fe-4S] as a critical cofactor in determining the fate of NCOA4 in favoring iron storage in ferritin or iron release via ferritinophagy and provide a dual mechanism for selective interaction between HERC2 and [3Fe-4S]-NCOA4 for proteasomal degradation or between ferritin and apo-NCOA4 for ferritinophagy in the control of iron homeostasis.

CEP20 promotes invasion and metastasis of non-small cell lung cancer cells by depolymerizing microtubules.

Worldwide, Lung cancer is the leading cause of cancer-related death and poses a direct health threat, non-small cell lung cancer (NSCLC) is the most common type. In this study, we demonstrated that centrosomal protein 20 (CEP20) is upregulated in NSCLC tissues and associated with cancer invasion metastasis. Notably, CEP20 depletion inhibited NSCLC cell proliferation, migration, and microtubule polymerization. Mechanistically, we discovered that CEP20 is critical in the development of NSCLC by regulating microtubule dynamics and cell adhesion-related signaling pathways. Furthermore, the knockdown or overexpression of CEP20 affects microtubule polymerization in A549 cell lines. Our research provides a promising therapeutic target for the diagnosis and treatment of lung cancer, as well as a theoretical and experimental basis for clinical application.

MiR-95-3p acts as a prognostic marker and promotes cervical cancer progression by targeting VCAM1.

Background: Cervical cancer patients have a high risk of metastasis and a poor prognosis with shorter disease-free survival. Thus, novel biomarkers and feasible therapies urgently need to be discovered. Previous studies have shown that miR-95-3p plays crucial roles in several cancer types. However, the roles of miR-95-3p in cervical cancer remain unknown. Methods: The micro ribonucleic acid (miRNA) expression data and clinical characteristics of cervical cancer samples were downloaded from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analyses were conducted to identify the prognostic-related miRNAs. The potential target genes of miR-95-3p were predicted by the TargetScan database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted to explore the target gene of miR-95-3p. The effects of miR-95-3p inhibition and overexpression on cell proliferation were inspected by cell counting kit-8 (CCK-8) assays and cell colony formation assays. Wound-healing assays and transwell assays were also used to examine cell migration ability in HeLa and SiHa cells. Results: MiR-95-3p was the only miRNA significantly associated with the poor prognosis of cervical squamous cell carcinoma. A further analysis suggested that vascular cell adhesion molecule 1 (VCAM1) is a target gene of miR-95-3p in cervical cancer, and miR-95-3p promotes the malignant behavior of cervical cancer cells by inhibiting the expression of VCAM1. The CCK-8 and cell colony assays showed that miR-95-3p downregulation significantly suppressed cell proliferation in the HeLa and SiHa cells. The transwell and wound-healing assays showed that miR-95-3p inhibition suppressed cell migration in the HeLa and SiHa cells. Further the Western blot analysis and the quantitative real-time-polymerase chain reaction (qRT-PCR) showed that the knockdown of miR-95-3p in HeLa cells resulted in increased VCAM1 expression. And VCAM1 was highly expressed in the paired adjacent normal cervical epithelium tissue samples, but lowly expressed in the cervical tumor tissue samples. Conclusions: Our study was the first to show that miR-95-3p could serve as a prognostic biomarker of cervical cancer. Mechanistically, we discovered that miR-95-3p inhibited the expression of the cell adhesion molecule VCAM1 and thus promoted further tumor progression.

GSK3ß inhibitor TDZD8 ameliorates brain damage through both ROS scavenging and inhibition of apoptosis in hyperglycaemic subarachnoid haemorrhage rats.

Hyperglycaemia is known to be associated with unfavourable outcomes in subarachnoid haemorrhage (SAH), but the pathogenic mechanism is unclear, and there is also a lack of effective therapeutic drugs in clinical practice. Phosphorylation of GSK3ß at serine 9 can inhibit its activity to further worsen SAH. The aim of the present study was to evaluate the protective effect and the potential mechanism of the GSK3ß inhibitor TDZD8 on brain injury in a hyperglycaemic SAH rat model. Hyperglycaemia was induced by intraperitoneal injection of streptozocin for 3 days. The SAH model was established by injecting fresh autologous femoral artery blood into the prechiasmatic cistern. p-GSK3ß (Ser9) expression was induced by intraperitoneal injection of TDZD8 (30 min post-SAH). The expression levels of GSK3ß, p-GSK3ß, SOD1/2, caspase 3, Bax and Bcl-2 were detected by western blot analysis. Terminal deoxynucleotidyl transferase dUTP nick end-labelling (TUNEL) staining was used to detect neuronal apoptosis of basal temporal lobe. Neurological scores were calculated to determine behavioural recovery. Neuronal survival was detected by Nissl staining. Hyperglycaemia significantly decreased p-GSK3ß expression, further exacerbated neurobehavioural deficits and increased oxidative stress and neuronal apoptosis in the brain after SAH compared to normal glycaemic SAH rats and hyperglycaemic rats. In addition, hyperglycaemic SAH rats had obvious oxidative stress and apoptosis. However, TDZD8 effectively decreased cleaved caspase 3 expression and TUNEL-positive cells and increased the Bcl2/Bax ratio, expression of SOD1/2 and activity of superoxide dismutase (SOD) enzyme compared with hyperglycaemic SAH rats. The GSK3ß inhibitor TDZD8 has therapeutic potential for hyperglycaemic SAH. The neuroprotective effect of TDZD8 appears to be mediated through its antioxidative and antiapoptotic activity.

Cur@SF NPs alleviate Friedreich's ataxia in a mouse model through synergistic iron chelation and antioxidation.

Abnormal iron metabolism, mitochondrial dysfunction and the derived oxidative damage are the main pathogeneses of Friedrich's ataxia (FRDA), a single-gene inherited recessive neurodegenerative disease characterized by progressive cerebellar and sensory ataxia. This disease is caused by frataxin (FXN) mutation, which reduces FXN expression and impairs iron sulfur cluster biogenesis. To date, there is no effective therapy to treat this condition. Curcumin is proposed harboring excellent ability to resist oxidative stress through Nrf2 activation and its newly found ability to chelate iron. However, its limitation is its poor water solubility and permeability. Here, we synthesized slow-release nanoparticles (NPs) by loading curcumin (Cur) into silk fibroin (SF) to form NPs with an average size of 150 nm (Cur@SF NPs), which exhibited satisfactory therapeutic effects on the improvement of FRDA manifestation in lymphoblasts (1 µM) derived from FRDA patients and in YG8R mice (150 mg/kg/5 days). Cur@SF NPs not only removed iron from the heart and diminished oxidative stress in general but also potentiate iron-sulfur cluster biogenesis, which compensates FXN deficiency to improve the morphology and function of mitochondria. Cur@SF NPs showed a significant advantage in neuron and myocardial function, thereby improving FRDA mouse behavior scores. These data encourage us to propose that Cur@SF NPs are a promising therapeutic compound in the application of FRDA disease.

Developmental and Histopathological Changes in the Gonads of Female Japanese Medaka Following Exposure to Water from the Yellow River, China.

Gonad development and histopathological changes typically associated with endocrine disruption were evaluated in female Japanese medaka (Oryzias latipes) exposed to river water from four representative cross-sections in the Yellow River (YR), China. Fish were held in the river water treatments from fertilization. Advanced ovarian development was observed in fish exposed to river water from Qinhe cross-section at 20 days post-hatch (dph) and in fish exposed to river water from all four cross-sections at 60 dph. Histopathological changes including increased oocyte atresia, perifollicular cell hyperplasia/hypertrophy, changes in ovarian staging, interstitial fibrosis and interstitial proteinaceous fluid were observed in the gonads of fish at 60 dph after exposure to river water from some cross-sections. Cytoplasmic retraction and karyoplasmic clumping were observed in fish exposed to river water from all four cross-sections at 60 dph. The results indicate that development and reproductive function in Yellow River fish is impaired, placing fish populations at risk.

Iron regulatory protein deficiency compromises mitochondrial function in murine embryonic fibroblasts.

Iron is essential for growth and proliferation of mammalian cells. The maintenance of cellular iron homeostasis is regulated by iron regulatory proteins (IRPs) through binding to the cognate iron-responsive elements in target mRNAs and thereby regulating the expression of target genes. Irp1 or Irp2-null mutation is known to reduce the cellular iron level by decreasing transferrin receptor 1 and increasing ferritin. Here, we report that Irp1 or Irp2-null mutation also causes downregulation of frataxin and IscU, two of the core components in the iron-sulfur cluster biogenesis machinery. Interestingly, while the activities of some of iron-sulfur cluster-containing enzymes including mitochondrial aconitase and cytosolic xanthine oxidase were not affected by the mutations, the activities of respiratory chain complexes were drastically diminished resulting in mitochondrial dysfunction. Overexpression of human ISCU and frataxin in Irp1 or Irp2-null cells was able to rescue the defects in iron-sulfur cluster biogenesis and mitochondrial quality. Our results strongly suggest that iron regulatory proteins regulate the part of iron sulfur cluster biogenesis tailored specifically for mitochondrial electron transport chain complexes.

Inhibition of myeloid differentiation primary response protein 88 provides neuroprotection in early brain injury following experimental subarachnoid hemorrhage.

Accumulating of evidence suggests that activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) exacerbates early brain injury (EBI) following subarachnoid hemorrhage (SAH) by provoking pro-inflammatory and pro-apoptotic signaling. Myeloid differentiation primary response protein 88 (MyD88) is an endogenous adaptor protein in the toll-like receptors (TLRs) and interleukin (IL) -1ß family signaling pathways and acts as a bottle neck in the NF-κB and MAPK pathways. Here, we used ST2825, a selective inhibitor of MyD88, to clarify whether inhibiting MyD88 could provide neuroprotection in EBI following SAH. Our results showed that the expression of MyD88 was markedly increased at 24 h post SAH. Intracerebroventricular injection of ST2825 significantly reduced the expression of MyD88 at 24 h post SAH. Involvement of MAPKs and NF-κB signaling pathways was revealed that ST2825 inhibited SAH-induced phosphorylation of TAK1, p38 and JNK, the nuclear translocation of NF-κB p65, and degradation of IκBα. Further, ST2825 administration diminished the SAH-induced inflammatory response and apoptosis. As a result, SAH-induced EBI was alleviated and neurological deficits caused by SAH were reversed. Our findings suggest that MyD88 inhibition confers marked neuroprotection against EBI following SAH. Therefore, MyD88 might be a promising new molecular target for the treatment of SAH.

Peptide SS-31 upregulates frataxin expression and improves the quality of mitochondria: implications in the treatment of Friedreich ataxia.

Friedreich ataxia is a progressive neurodegenerative disease caused by the expansion of GAA trinucleotide repeats within the first intron of the FXN gene, which encodes frataxin. The pathophysiology of the disease is thought to be derived from the decrease of Fe-S cluster biogenesis due to frataxin deficiency. There is currently no effective treatment for the disease. In our study, we demonstrated that treatment with the mitochondrion-targeted peptide SS-31 reduced frataxin deficiency-induced oxidative stress in lymphoblasts and fibroblasts derived from patients. Interestingly, SS-31 treatment translationally upregulated the protein level of frataxin in a dose-dependent manner. Furthermore, SS-31 treatment increased the enzymatic activities of the iron-sulphur enzymes, including aconitase and complex II and III of the respiratory chain. Further evaluation of the quality of mitochondria showed that mitochondrial membrane potential, ATP content, NAD+/NADH, and the morphology of mitochondria all improved. Our results suggest that SS-31 might potentially be a new drug for the early treatment of Friedreich ataxia.

Elamipretide (SS-31) Ameliorates Isoflurane-Induced Long-Term Impairments of Mitochondrial Morphogenesis and Cognition in Developing Rats.

Mitochondria are supposed to be involved in the early pathogenesis of general anesthesia (GA)-induced neurotoxicity and long-term cognitive deficits in developing brains. However, effective pharmacologic agents targeted on mitochondria during GA exposure are lacking. This study explores the protective effects of mitochondrion-targeted antioxidant elamipretide (SS-31) on mitochondrial morphogenesis and cognition in developing rats exposed to isoflurane. Rat pups at postnatal day (PND) 7 were exposed to 1.5% isoflurane for 6 h following intraperitoneal administration of elamipretide or vehicle with 30 min interval. The hippocampus was immediately removed for biochemical assays. Histopathological studies were conducted at PND 21, and behavioral tests were performed at PND 40 or 60. We found that early exposure to isoflurane caused remarkable reactive oxygen species (ROS) accumulation, mitochondrial deformation and neuronal apoptosis in hippocampus. The injury occurrence ultimately gave rise to long-term cognitive deficits in developing rats. Interestingly, pretreatment with elamipretide not only provided protective effect against oxidative stress and mitochondrial damages, but also attenuated isoflurane-induced cognitive deficits. Our data support the notion that mitochondrial damage is an early and long lasting event of GA-induced injury and suggest that elamipretide might have clinically therapeutic benefits for pediatric patients undertaking GA.

Protective effect of melatonin on the development of abdominal aortic aneurysm in a rat model.

BACKGROUND: Oxidative injury, inflammation, and apoptosis are involved in the progression of abdominal aortic aneurysm (AAA). Melatonin (MLT) has been reported with an effective antioxidant activity. The objective of the present study was to investigate whether MLT could suppress the development of AAA. METHODS: The AAA model was introduced by intraluminal perfusion of elastase in rats. All rats were divided into three groups as follows: (1) sham; (2) AAA + vehicle; and (3) AAA + MLT. Daily administration of MLT (10 mg/kg/d) or vehicle started 3 d before the perfusion and continued for 28 d after perfusion. An ultrasound system was applied to measure the dilation of the aorta. Histologic assays were performed to evaluate the structure, morphology, and apoptotic cells of the aortas; biochemical assays to determine the levels of proteins and lipid peroxide, activities of superoxide dismutase and NADPH oxidases, and cell viability; dihydroethidium fluorescence staining and flow cytometry to detect the presence of reactive oxygen species, and/or cell apoptosis; and electron microscopy to observe the ultrastructure of mitochondria. Cell lines A7R5 and RAW 264.7 were used for in vitro experiments. RESULTS: MLT treatment inhibited dilation of the aorta very likely through its antioxidant property; significantly reduced the levels of lipid peroxide, activities of NADPH oxidases, and content of reactive oxygen species; remarkably inhibited NF-κB signaling pathway and activities of matrix metalloproteinases triggered by elastase perfusion. As a result, the mitochondrion-dependent apoptosis was suppressed, cellular energy (ATP) supply was recovered, and mitochondrial morphology remained intact. CONCLUSIONS: Our results demonstrate the beneficial effects of MLT on inhibition of AAA formation, suggesting that MLT could be a potential agent for prevention of the development of human AAA.

Iron Together with Lipid Downregulates Protein Levels of Ceruloplasmin in Macrophages Associated with Rapid Foam Cell Formation.

AIM: Iron accumulation in foam cells was previously shown to be involved in atherogenesis. However, the mechanism for iron accumulation was not clarified. Ceruloplasmin (Cp) is an important factor in cellular iron efflux and was found to be downregulated in atherosclerotic plaques in our previous study. The current study is to investigate the role of Cp in atherosclerosis. METHODS: We used RAW264.7 cells, a well-accepted cell model of atherosclerosis, which were treated with lipopolysaccharides (LPS), ferric ammonium citrate (FAC) or deferoxamine, and oxidized low density lipoprotein (ox-LDL) to detect the regulation of Cp and its influence in iron efflux and lipid accumulation using biochemical and histological assays. RESULTS: Our results showed that the Cp protein level increased after 200-µM FAC treatment in LPS-activated RAW264.7 cells. Ox-LDL treatment (50 µg/ml) moderately reduced both mRNA and protein levels and ferroxidase activity of Cp (p＜0.05). No significant difference was observed in the expression of ferritin and ferroportin, two important iron-related proteins for iron storage and efflux, respectively, after ox-LDL treatment. However, co-treatment with ox-LDL and FAC drastically reduced the expression of Cp. Accordingly, the ferroxidase activities simultaneously decreased, whereas the protein levels of Ft and Fpn1 significantly increased, indicating further iron accumulation. Moreover, co-treatment with FAC and ox-LDL enhanced the accumulation of cholesterol compared with ox-LDL-only treatment to trigger apoptosis. CONCLUSION: Our findings suggest that physiological interaction of iron and lipid obstructs iron efflux and accelerates the lipid accumulation in macrophages during foam cell formation, which implicates the role of iron in the pathology of atherosclerosis.

BDNF pathway is involved in the protective effects of SS-31 on isoflurane-induced cognitive deficits in aging mice.

Mitochondrial dysfunction has been linked to the earliest pathogenesis of isoflurane-induced cognitive impairments in developing or aging mammalian brain. However, its molecular mechanism is poorly understood and a pharmacologic treatment to rapidly reverse mitochondrial dysfunction is lacking. Fifteen-month-old male C57BL/6 mice were exposed to isoflurane for two hours following intraperitoneal administration of mitochondrion-targeted peptide SS-31 or vehicle with 30min interval. The hippocampus was immediately removed for biochemical assays and mitochondria isolation after inhalation. Behavioral tests were evaluated by the open field test and fear conditioning test 24h after the experiment. We showed that cognitive deficits induced by exposure of the aging mice to isoflurane were accompanied by mitochondrial dysfunction in hippocampus due to loss of the enzymatic activity of complex I. This loss resulted in the increase of reactive oxygen species production, decrease of ATP production and mitochondrial membrane potential, and opening of mitochondrial permeability transition pore. Further, we provided evidence that the BDNF signaling pathway was involved in this process to regulate synaptic plasticity-related proteins, for instance, downregulation of synapsin 1, PSD-95 and p-CREB, and upregulation of NR2A, NR2B, CaMKIIα and CaMKIIß. Of note, the isoflurane-induced cognitive deficits were rescued by SS-31 through reversal of mitochondrial dysfunction, which facilitated the regulation of BDNF signaling including the expression reversal of aforementioned important synaptic-signaling proteins in aging mice. Our data demonstrate that reversing mitochondrial dysfunction by SS-31 enhances BDNF signaling pathway and synaptic plasticity, and provides protective effects on cognitive function, thereby support the notion that SS-31 may have therapeutic benefits for elderly humans undertaking anesthesia.

Phosphorylation of Akt by SC79 Prevents Iron Accumulation and Ameliorates Early Brain Injury in a Model of Experimental Subarachnoid Hemorrhage.

Previous studies have demonstrated that activation of Akt may alleviate early brain injury (EBI) following subarachnoid hemorrhage (SAH). This study is undertaken to determine whether iron metabolism is involved in the beneficial effect of Akt activation after SAH. Therefore, we used a novel molecule, SC79, to activate Akt in an experimental Sprague-Dawley rat model of SAH. Rats were randomly divided into four groups as follows: sham, SAH, SAH + vehicle, SAH + SC79. The results confirmed that SC79 effectively enhanced the defense against oxidative stress and alleviated EBI in the temporal lobe after SAH. Interestingly, we found that phosphorylation of Akt by SC79 reduced cell surface transferrin receptor-mediated iron uptake and promoted ferroportin-mediated iron transport after SAH. As a result, SC79 administration diminished the iron content in the brain tissue. Moreover, the impaired Fe-S cluster biogenesis was recovered and loss of the activities of the Fe-S cluster-containing enzymes were regained, indicating that injured mitochondrial functions are restored to healthy levels. These findings suggest that disrupted iron homeostasis could contribute to EBI and Akt activation may regulate iron metabolism to relieve iron toxicity, further protecting neurons from EBI after SAH.

Akt Specific Activator SC79 Protects against Early Brain Injury following Subarachnoid Hemorrhage.

A growing body of evidence demonstrates that Akt may serve as a therapeutic target for treatment of early brain injury following subarachnoid hemorrhage (SAH). The purpose of the current study was to evaluate the neuroprotective effect of Akt specific activator SC79 in an experimental rat model of SAH. SAH was induced by injecting 300 µL of blood into the prechiasmatic cistern. Intracerebroventricular (ICV) injection of SC79 (30 min post-SAH) induced the p-Akt (Ser473) expression in a dose-dependent manner. A single ICV dose treatment of SC79 (100 µg/rat) significantly increased the expression of Bcl-2 and p-GSK-3ß (Ser9), decreased the protein levels of Bax, cytoplasm cytochrome c, and cleaved caspase-3, indicating the antiapoptotic effect of SC79. As a result, the number of apoptotic cells was reduced 24 h post SAH. Moreover, SC79 treatment alleviated SAH-induced oxidative stress, restored mitochondrial morphology, and improved neurological deficits. Strikingly, treatment of SC79 provided a beneficial outcome against neurologic deficit with a therapeutic window of at least 4 h post SAH by ICV injection and 30 min post SAH by intraperitoneal injection. Collectively, SC79 exerts its neuroprotective effect likely through the dual activities of antioxidation and antiapoptosis. These data provide a basic platform to consider SC79 as a novel therapeutic agent for treatment of SAH.

Mitochondrion-Targeted Peptide SS-31 Inhibited Oxidized Low-Density Lipoproteins-Induced Foam Cell Formation through both ROS Scavenging and Inhibition of Cholesterol Influx in RAW264.7 Cells.

Foam cell formation as a result of imbalance of modified cholesterol influx and efflux by macrophages is a key to the occurrence and development of atherosclerosis. Oxidative stress is thought to be involved in the pathogenesis of atherosclerosis. SS-31 is a member of the Szeto-Schiller (SS) peptides shown to specifically target the inner mitochondrial membrane to scavenge reactive oxygen species. In this study, we investigated whether SS-31 may provide protective effect on macrophage from foam cell formation in RAW264.7 cells. The results showed that SS-31 inhibited oxidized low-density lipoproteins (ox-LDL)-induced foam cell formation and cholesterol accumulation, demonstrated by intracellular oil red O staining and measurement of cholesterol content. The mechanism was revealed that SS-31 did not only significantly attenuated ox-LDL-induced generation of reactive oxygen species (ROS) and increased the activities of superoxide dismutases, but also dose-dependently inhibited the expression of CD36 and LOX-1, two scavenger receptors of ox-LDL, while the expression of ATP-binding cassette A1 and G1, playing a pivotal role in cholesterol efflux, was not affected. As a result, SS-31 decreased pro-inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha, suggesting the prevention of inflammatory responses. In conclusion, our results demonstrate that SS-31 provides a beneficial effect on macrophages from foam cell formation, likely, through both ROS scavenging and inhibition of cholesterol influx. Therefore, SS-31 may potentially be of therapeutic relevance in prevention of human atherogenesis.

A Mitochondrion-Targeted Antioxidant Ameliorates Isoflurane-Induced Cognitive Deficits in Aging Mice.

Isoflurane possesses neurotoxicity and can induce cognitive deficits, particularly in aging mammals. Mitochondrial reactive oxygen species (mtROS) have been linked to the early pathogenesis of this disorder. However, the role of mtROS remains to be evaluated due to a lack of targeted method to treat mtROS. Here, we determined in aging mice the effects of the mitochondrion-targeted antioxidant SS-31, on cognitive deficits induced by isoflurane, a general inhalation anesthetic. We further investigated the possible mechanisms underlying the effects of SS-31 on hippocampal neuro-inflammation and apoptosis. The results showed that isoflurane induced hippocampus-dependent memory deficit, which was associated with mitochondrial dysfunction including reduced ATP contents, increased ROS levels, and mitochondrial swelling. Treatment with SS-31 significantly ameliorated isoflurane-induced cognitive deficits through the improvement of mitochondrial integrity and function. Mechanistically, SS-31 treatment suppressed pro-inflammatory responses by decreasing the levels of NF-κB, NLRP3, caspase 1, IL-1ß, and TNF-α; and inhibited the apoptotic pathway by decreasing the Bax/Bcl-2 ratio, reducing the release of cytochrome C, and blocking the cleavage of caspase 3. Our results indicate that isoflurane-induced cognitive deficits may be attenuated by mitochondrion-targeted antioxidants, such as SS-31. Therefore, SS-31 may have therapeutic potentials in preventing injuries from oxidative stresses that contribute to anesthetic-induced neurotoxicity.