COX6B1 relieves hypoxia/reoxygenation injury of neonatal rat cardiomyocytes by regulating mitochondrial function

TWEAK-Fn14 signaling protects mice from pulmonary fibrosis by inhibiting fibroblast activation and recruiting pro-regenerative macrophages

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterized by excess accumulation of the extracellular matrix (ECM). The role of macrophage-fibroblast crosstalk in lung fibrogenesis is incompletely understood. Here we found that fibroblast growth factor-inducible molecule 14 (Fn14), the receptor for tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is highly induced in myofibroblasts in the lungs of IPF patients and the bleomycin-induced lung fibrosis model. TWEAK-Fn14 signaling inhibits fibroblast activation and ECM synthesis and induces chemokine expression to recruit monocytes/macrophages into the lung. Fn14 deficiency increases ECM production and impairs macrophage infiltration and differentiation, leading to exacerbated lung fibrosis and impaired alveolar regeneration in a bleomycin model. Interestingly, Fn14 deficiency diminishes an injury-induced SiglecF- CD11b- MHCIIlo intermediate macrophage (IntermM) subpopulation, which promotes alveolar type II (AT2) cell proliferation in organoid cultures. These results collectively demonstrate a protective role of TWEAK-Fn14 signaling in lung fibrosis, highlighting the complexities and multilayered regulation of macrophage-fibroblast crosstalk.

Integrating genome- and transcriptome-wide association studies to uncover the host-microbiome interactions in bovine rumen methanogenesis

The ruminal microbiota generates biogenic methane in ruminants. However, the role of host genetics in modifying ruminal microbiota-mediated methane emissions remains mysterious, which has severely hindered the emission control of this notorious greenhouse gas. Here, we uncover the host genetic basis of rumen microorganisms by genome- and transcriptome-wide association studies with matched genome, rumen transcriptome, and microbiome data from a cohort of 574 Holstein cattle. Heritability estimation revealed that approximately 70% of microbial taxa had significant heritability, but only 43 genetic variants with significant association with 22 microbial taxa were identified through a genome-wide association study (GWAS). In contrast, the transcriptome-wide association study (TWAS) of rumen microbiota detected 28,260 significant gene-microbe associations, involving 210 taxa and 4652 unique genes. On average, host genetic factors explained approximately 28% of the microbial abundance variance, while rumen gene expression explained 43%. In addition, we highlighted that TWAS exhibits a strong advantage in detecting gene expression and phenotypic trait associations in direct effector organs. For methanogenic archaea, only one significant signal was detected by GWAS, whereas the TWAS obtained 1703 significant associated host genes. By combining multiple correlation analyses based on these host TWAS genes, rumen microbiota, and volatile fatty acids, we observed that substrate hydrogen metabolism is an essential factor linking host-microbe interactions in methanogenesis. Overall, these findings provide valuable guidelines for mitigating methane emissions through genetic regulation and microbial management strategies in ruminants.

The Effect of Mulberry Silage Supplementation on the Carcass Fatness and Long-Chain Fatty Acid Composition of Growing Lambs Compared with Traditional Corn Silage

Lamb meat has become very popular with consumers in recent years due to its nutritional benefits. As a lean red meat, lamb is an important natural source of polyunsaturated and saturated fatty acids, which can be modified by adjustments in livestock feed. This study used proteomic and metabolic analyses to compare a basal ration supplemented with either mulberry silage or corn silage. Supplementation with mulberry silage led to a reduction in subcutaneous carcass fatness compared with corn silage. Additionally, changes in the proteome associated with fatty acid metabolism and oxidation resulted in decreased levels of saturated and trans fatty acids, while significantly increasing the levels of α-linolenic acid (ALA) and oleic acid and reducing linoleic acid content.

Ablation of Vitamin D Signaling in Cardiomyocytes Leads to Functional Impairment and Stimulation of Pro-Inflammatory and Pro-Fibrotic Gene Regulatory Networks in a Left Ventricular Hypertrophy Model in Mice

The association between vitamin D deficiency and cardiovascular disease remains a controversial issue. This study aimed to further elucidate the role of vitamin D signaling in the development of left ventricular (LV) hypertrophy and dysfunction. To ablate the vitamin D receptor (VDR) specifically in cardiomyocytes, VDRfl/fl mice were crossed with Mlcv2-Cre mice. To induce LV hypertrophy experimentally by increasing cardiac afterload, transverse aortic constriction (TAC) was employed. Sham or TAC surgery was performed in 4-month-old, male, wild-type, VDRfl/fl, Mlcv2-Cre, and cardiomyocyte-specific VDR knockout (VDRCM-KO) mice. As expected, TAC induced profound LV hypertrophy and dysfunction, evidenced by echocardiography, aortic and cardiac catheterization, cardiac histology, and LV expression profiling 4 weeks post-surgery. Sham-operated mice showed no differences between genotypes. However, TAC VDRCM-KO mice, while having comparable cardiomyocyte size and LV fibrosis to TAC VDRfl/fl controls, exhibited reduced fractional shortening and ejection fraction as measured by echocardiography. Spatial transcriptomics of heart cryosections revealed more pronounced pro-inflammatory and pro-fibrotic gene regulatory networks in the stressed cardiac tissue niches of TAC VDRCM-KO compared to VDRfl/fl mice. Hence, our study supports the notion that vitamin D signaling in cardiomyocytes plays a protective role in the stressed heart.

Mechanisms underlying retardation of aging by dietary energy restriction

Moderate restriction of dietary energy intake, referred to here as dietary restriction (DR), delays aging and extends lifespan in experimental animals compared with a diet of ad libitum feeding (AL) control animals. Basic knowledge of the mechanisms underlying the effects of DR could be applicable to extending the healthspan in humans. This review highlights the importance of forkhead box O (FoxO) transcription factors downstream of the growth hormone-insulin-like growth factor 1 signaling in the effects of DR. Our lifespan studies in mice with heterozygous Foxo1 or Foxo3 gene knockout indicated differential roles of FoxO1 and FoxO3 in the tumor-inhibiting and life-extending effects of DR. Subsequent studies suggested a critical role of FoxO3 in metabolic and mitochondrial bioenergetic adaptation to DR. Our studies also verified hypothalamic neuropeptide Y (Npy) as a vital neuropeptide showing pleiotropic and sexually dimorphic effects for extending the healthspan in the context of nutritional availability. Npy was necessary for DR to exert its effects in male and female mice; meanwhile, under AL conditions, the loss of Npy prevented obesity and insulin resistance only in female mice. Overnutrition disrupts FoxO- and Npy-associated metabolic and mitochondrial bioenergetic adaptive processes, causing the acceleration of aging and related diseases.

Chronic dehydration induces injury pathways in rats, but does not mimic histopathology of chronic interstitial nephritis in agricultural communities

CINAC-patients present renal proximal tubular cell lysosomal lesions which are also observed in patients experiencing calcineurin inhibitor (CNI) nephrotoxicity, suggesting that CINAC is a toxin-induced nephropathy. An alternative hypothesis advocates chronic dehydration as a major etiological factor for CINAC. Here, we evaluated histological and molecular changes in dehydrated versus toxin exposed rats. Wistar rats were divided in 3 groups. Group 1 (n = 6) had free access to drinking water (control group). Group 2 (n = 8) was water deprived for 10 h per 24 h, 5 days/week and placed in an incubator (37 °C) for 30 min/h during water deprivation. Group 3 (n = 8) underwent daily oral gavage with cyclosporine (40 mg/kg body weight). After 28 days, renal function, histopathology and proteomic signatures were analysed. Cyclosporine-treated rats developed focal regions of atrophic proximal tubules with associated tubulo-interstitial fibrosis. PASM staining revealed enlarged argyrophilic granules in affected proximal tubules, identified as lysosomes by immunofluorescent staining. Electron microscopy confirmed the enlarged and dysmorphic phenotype of the lysosomes. Overall, these kidney lesions resemble those that have been previously documented in farmers with CINAC. Dehydration resulted in none of the above histopathological features. Proteomic analysis revealed that dehydration and cyclosporine both induce injury pathways, yet of a clear distinct nature with a signature of toxicity only for the cyclosporine group. In conclusion, both cyclosporine and dehydration are injurious to the kidney. However, dehydration alone does not result in kidney histopathology as observed in CINAC patients, whereas cyclosporine administration does. The histopathological analogy between CINAC and calcineurin inhibitor nephrotoxicity in rats and humans supports the involvement of an as-yet-unidentified environmental toxin in CINAC etiology.

Protective effects of Shen Yuan Dan on myocardial ischemia-reperfusion injury via the regulation of mitochondrial quality control

Background

Myocardial cell death resulting from ischemia-reperfusion (I/R) injury has been a predominant contributor to morbidity and mortality globally. The mitochondria-centered mechanism plays an important role in the formation of I/R injury. This study intended to discuss the protective mechanism of Shen Yuan Dan (SYD) on cardiomyocytes hypoxia-reoxygenation (H/R) injury via the regulation of mitochondrial quality control (MQC). Additionally, this study clarified the mechanism by which SYD suppressed mitophagy activity through the suppression of the PTEN-induced kinase 1 (PINK1)/Parkin pathway.

Methods

To induce cellular injury, H9c2 cardiomyocytes were exposed to H/R stimulation. Following the pretreatment with SYD, cardiomyocytes were subjected to H/R stimulation. Mitochondrial membrane potential (MMP), adenosine triphosphate (ATP), superoxide dismutase (SOD), and methane dicarboxylic aldehyde (MDA) were detected to evaluate the degree of cardiomyocyte mitochondrial damage. Laser confocal microscopy was applied to observe the mitochondrial quality, and the messenger (mRNA) levels of mitofusin 1 (Mfn1), mitofusin 2 (Mfn2), optic atrophy protein 1 (Opa1), dynamin-related protein 1 (Drp1), fission 1 (Fis1), and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) in cardiomyocytes were assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Western blotting was employed for the estimation of light chain 3 (LC3)-I, LC3-II, PINK1, and Parkin in cardiomyocytes.

Results

It was discovered that SYD pretreatment elevated MMP in H/R injury cardiomyocytes, enhanced ATP content, activated SOD activity, and reduced MDA level. SYD treatment increased the mRNA levels of Mfn1, Mfn2, Opa1 and PGC-1α decreased the mRNA levels of Drp1 and Fis1, and reduced the protein levels of LC3, PINK1, and Parkin.

Conclusions

SYD plays a protective role in H/R injury to cardiomyocytes by regulating mitochondrial quality. Meanwhile, SYD may inhibit mitophagy activity through inhibiting the PINK1/Parkin pathway. This study provides insights into the underlying mechanism of SYD in alleviating myocardial I/R injury.

Theory and Applications of the (Cardio) Genomic Fabric Approach to Post-Ischemic and Hypoxia-Induced Heart Failure

The genomic fabric paradigm (GFP) characterizes the transcriptome topology by the transcripts’ abundances, the variability of the expression profile, and the inter-coordination of gene expressions in each pathophysiological condition. The expression variability analysis provides an indirect estimate of the cell capability to limit the stochastic fluctuations of the expression levels of key genes, while the expression coordination analysis determines the gene networks in functional pathways. This report illustrates the theoretical bases and the mathematical framework of the GFP with applications to our microarray data from mouse models of post ischemic, and constant and intermittent hypoxia-induced heart failures. GFP analyses revealed the myocardium priorities in keeping the expression of key genes within narrow intervals, determined the statistically significant gene interlinkages, and identified the gene master regulators in the mouse heart left ventricle under normal and ischemic conditions. We quantified the expression regulation, alteration of the expression control, and remodeling of the gene networks caused by the oxygen deprivation and determined the efficacy of the bone marrow mono-nuclear stem cell injections to restore the normal transcriptome. Through the comprehensive assessment of the transcriptome, GFP would pave the way towards the development of personalized gene therapy of cardiac diseases.

iTRAQ-based quantitative proteomic analysis of Pelteobagrus vachelli liver in response to hypoxia

Dissolved oxygen is one of the determinants in the healthy farming of Pelteobagrus vachelli. This study, we conducted quantitative proteomics on the juvenile P. vachelli livers using iTRAQ. P. vachelli were treated by 3.75 ± 0.25 mg O₂/L (hypoxia group) and 7.25 ± 0.25 mg O₂/L (control group) for 90 days. The results revealed that under hypoxic conditions, P. vachelli grew slower than control group. Proteomic profiling enabled us to identify 2618 proteins, of which 176 were significantly differentially abundant proteins (DAPs). Verification of protein regulation based on qRT-PCR indicated that the proteomics data were reliable. The top 20 significantly DAPs (10 up-regulated, 10 down-regulated) were primarily involved in energy metabolism, apoptosis inhibition, and heavy metal detoxification. KEGG pathway enrichment analysis revealed significant enrichment of 'protein digestion and absorption', 'glycolysis/gluconeogenesis', and 'phagosome'. Combining the proteomics results of short-term hypoxia (treated with 0.70 ± 0.10 mg O₂ /L for 4 h), we screened 36 common DAPs. The analysis of the 36 common DAPs indicated that P. vachelli responded to the hypoxia by regulating energy supply, inhibiting apoptosis, and disturbing defensive system. Our results lay a theoretical foundation for the cultivation of hypoxia-tolerant species and eco-breeding of P. vachelli. SIGNIFICANCE OF THE STUDY: The hypoxia tolerance of Pelteobagrus vachelli is poor, which will seriously lead to its death in high-density culture. This study analysed the liver proteome of P. vachelli under long-term hypoxia stress (treated for 90 days at 3.75 ± 0.25 mg O₂/L), and then combined the proteome results of short-term hypoxia stress (treated for 4 h at 0.70 ± 0.10 mg O₂/L). The results showed P. vachelli responded to the hypoxia by regulating energy supply, inhibiting apoptosis and disturbing defensive system. The study contributes to the breeding of new hypoxia-tolerant species of P. vachelli and lays the theoretical foundation for eco-breeding.

The Secretome of Human Neonatal Mesenchymal Stem Cells Modulates Doxorubicin-Induced Cytotoxicity: Impact in Non-Tumor Cells

Doxorubicin (Dox) is one of the most widely used treatments for breast cancer, although limited by the well-documented cardiotoxicity and other off-target effects. Mesenchymal stem cell (MSC) secretome has shown immunomodulatory and regenerative properties, further potentiated under 3D conditions. This work aimed to uncover the effect of the MSC-derived secretome from 3D (CM3D) or 2D (CM2D) cultures, in human malignant breast cells (MDA-MB-231), non-tumor breast epithelial cells (MCF10A) and differentiated AC16 cardiomyocytes, co-treated with Dox. A comprehensive proteomic analysis of CM3D/CM2D was also performed to unravel the underlying mechanism. CM3D/CM2D co-incubation with Dox revealed no significant differences in MDA-MB-231 viability when compared to Dox alone, whereas MCF10A and AC16 viability was consistently improved in Dox+CM3D-treated cells. Moreover, neither CM2D nor CM3D affected Dox anti-migratory and anti-invasive effects in MDA-MB-231. Notably, Ge-LC-MS/MS proteomic analysis revealed that CM3D displayed protective features that might be linked to the regulation of cell proliferation (CAPN1, CST1, LAMC2, RANBP3), migration (CCN3, MMP8, PDCD5), invasion (TIMP1/2), oxidative stress (COX6B1, AIFM1, CD9, GSR) and inflammation (CCN3, ANXA5, CDH13, GDF15). Overall, CM3D decreased Dox-induced cytotoxicity in non-tumor cells, without compromising Dox chemotherapeutic profile in malignant cells, suggesting its potential use as a chemotherapy adjuvant to reduce off-target side effects.

Mutations in the Yeast Cox12 Subunit Severely Compromise the Activity of the Mitochondrial Complex IV

Cytochrome c oxidase 6B1 (COX6B1) is one of the less characterized subunits of the mitochondrial electron transport chain complex IV (CIV). Here, we studied the pathobiochemical and respiratory functions of Cox12 (yeast ortholog of COX6B1) using Saccharomyces cerevisiae BY4741 (cox12Δ) cells deficient by the Cox12 protein. The cells exhibited severe growth deficiency in the respiratory glycerol-ethanol medium, which could be reverted by complementation with the yeast COX12 or human COX6B1 genes. Cox12 with arginine 17 residue substituted by histidine (R17H) or cysteine (R17C) (mutations analogous to those observed in human patients) failed to complement the loss of Cox12 function. When cox12Δ cells were grown in rich respiratory/fermentative galactose medium, no changes in the expression of individual respiratory chain subunits were observed. Blue native PAGE/Western blotting analysis using antibodies against Rip1 and Cox1, which are specific components of complexes III (CIII) and IV (CIV), respectively, revealed no noticeable decrease in the native CIII₂CIV₂ and CIII₂CIV₁ supercomplexes (SCs). However, the association of the respiratory SC factor 2 (Rcf2) and Cox2 subunit within the SCs of cox12Δ cells was reduced, while the specific activity of CIV was downregulated by 90%. Both basal respiration and succinate-ADP stimulated state 3 respiration, as well as the mitochondrial membrane potential, were decreased in cox12Δ cells. Furthermore, cox12Δ cells and cells synthesizing Cox12 mutants R17H and R17C showed higher sensitivity to the H2O2-induced oxidative stress compared to the wild-type (WT) cells. In silico structural modeling of the WT yeast SCs revealed that Cox12 forms a network of interactions with Rcf2 and Cox2. Together, our results establish that Cox12 is essential for the CIV activity.

Sildenafil improves right ventricular remodelling in monocrotaline-induced rats by decreasing myocardial apoptosis and activating peroxisome proliferator-activated receptors

OBJECTIVES

To assess the effect of sildenafil on monocrotaline-induced right ventricular (RV) remodeling and investigate the possible mechanism.

METHODS

Rats were subcutaneously injected with monocrotaline to establish an RV remodeling model and then administered sildenafil (25 mg/kg) from days 1 to 28. After 28 days of administration, the RV systolic pressure and the RV hypertrophy index (RVHI) were measured. The morphology of the right ventricle was observed by H&E staining. The ultrastructure of the right ventricle was observed using a transmission electron microscope. The myocardial apoptosis of the right ventricle was evaluated by TUNEL staining. The protein expression of apoptosis-related proteins and PPARs were examined by western blotting.

KEY FINDINGS

The results indicated that sildenafil decreased the RV systolic pressure and RVHI, and improved the microstructure and ultrastructure of the right ventricle in monocrotaline-induced rats. In addition, sildenafil suppressed myocardial apoptosis and promoted the protein expression of PPARs of the right ventricle in monocrotaline-induced rats.

CONCLUSION

Sildenafil inhibits RV remodeling in monocrotaline-induced rats, which might be partially mediated by reducing myocardial apoptosis and activating PPARs.

Multiple Mechanisms Regulate Eukaryotic Cytochrome C Oxidase

Cytochrome c oxidase (COX), the rate-limiting enzyme of mitochondrial respiration, is regulated by various mechanisms. Its regulation by ATP (adenosine triphosphate) appears of particular importance, since it evolved early during evolution and is still found in cyanobacteria, but not in other bacteria. Therefore the "allosteric ATP inhibition of COX" is described here in more detail. Most regulatory properties of COX are related to "supernumerary" subunits, which are largely absent in bacterial COX. The "allosteric ATP inhibition of COX" was also recently described in intact isolated rat heart mitochondria.

Proteomic Characterization of Proliferation Inhibition of Well-Differentiated Laryngeal Squamous Cell Carcinoma Cells Under Below-Background Radiation in a Deep Underground Environment

Background: There has been a considerable concern about cancer induction in response to radiation exposure. However, only a limited number of studies have focused on the biological effects of below-background radiation (BBR) in deep underground environments. To improve our understanding of the effects of BBR on cancer, we studied its biological impact on well-differentiated laryngeal squamous cell carcinoma cells (FD-LSC-1) in a deep underground laboratory (DUGL). Methods: The growth curve, morphological, and quantitative proteomic experiments were performed on FD-LSC-1 cells cultured in the DUGL and above-ground laboratory (AGL). Results: The proliferation of FD-LSC-1 cells from the DUGL group was delayed compared to that of cells from the AGL group. Transmission electron microscopy scans of the cells from the DUGL group indicated the presence of hypertrophic endoplasmic reticulum (ER) and a higher number of ER. At a cutoff of absolute fold change ≥ 1.2 and p < 0.05, 807 differentially abundant proteins (DAPs; 536 upregulated proteins and 271 downregulated proteins in the cells cultured in the DUGL) were detected. KEGG pathway analysis of these DAPs revealed that seven pathways were enriched. These included ribosome (p < 0.0001), spliceosome (p = 0.0001), oxidative phosphorylation (p = 0.0001), protein export (p = 0.0001), thermogenesis (p = 0.0003), protein processing in the endoplasmic reticulum (p = 0.0108), and non-alcoholic fatty liver disease (p = 0.0421). Conclusion: The BBR environment inhibited the proliferation of FD-LSC-1 cells. Additionally, it induced changes in protein expression associated with the ribosome, gene spliceosome, RNA transport, and energy metabolism among others. The changes in protein expression might form the molecular basis for proliferation inhibition and enhanced survivability of cells adapting to BBR exposure in a deep underground environment. RPL26, RPS27, ZMAT2, PRPF40A, SNRPD2, SLU7, SRSF5, SRSF3, SNRPF, WFS1, STT3B, CANX, ERP29, HSPA5, COX6B1, UQCRH, and ATP6V1G1 were the core proteins associated with the BBR stress response in cells.

Glioma cells are resistant to inflammation‑induced alterations of mitochondrial dynamics

Accumulating evidence suggests that inflammation is present in solid tumors. However, it is poorly understood whether inflammation exists in glioma and how it affects the metabolic signature of glioma. By analyzing immunohistochemical data and gene expression data downloaded from bioinformatic datasets, the present study revealed an accumulation of inflammatory cells in glioma, activation of microglia, upregulation of proinflammatory factors (including IL-6, IL-8, hypoxia-inducible factor-1α, STAT3, NF-κB1 and NF-κB2), destruction of mitochondrial structure and altered expression levels of electron transfer chain complexes and metabolic enzymes. By monitoring glioma cells following proinflammatory stimulation, the current study observed a remodeling of their mitochondrial network via mitochondrial fission. More than half of the mitochondria presented ring-shaped or spherical morphologies. Transmission electron microscopic analyses revealed mitochondrial swelling with partial or total cristolysis. Furthermore, proinflammatory stimuli resulted in increased generation of reactive oxygen species, decreased mitochondrial membrane potential and reprogrammed metabolism. The defective mitochondria were not eliminated via mitophagy. However, cell viability was not affected, and apoptosis was decreased in glioma cells after proinflammatory stimuli. Overall, the present findings suggested that inflammation may be present in glioma and that glioma cells may be resistant to inflammation-induced mitochondrial dysfunction.

Xenon blunts NF-κB/NLRP3 inflammasome activation and improves acute onset of accelerated and severe lupus nephritis in mice

Xenon, an inert anesthetic gas, is increasingly recognized to possess desirable properties including cytoprotective and anti-inflammatory effects. Here we evaluated the effects of xenon on the progression of lupus nephritis (LN) in a mouse model. A two hour exposure of either 70% xenon or 70% nitrogen balanced with oxygen was administered daily for five weeks to female NZB/W F1 mice that had been induced to develop accelerated and severe LN. Xenon treatment improved kidney function and renal histology, and decreased the renal expression of neutrophil chemoattractants, thereby attenuating glomerular neutrophil infiltration. The effects of xenon were mediated primarily by deceasing serum levels of anti-double stranded DNA autoantibody, inhibiting reactive oxygen species production, NF-κB/NLRP3 inflammasome activation, ICAM-1 expression, glomerular deposition of IgG and C3 and apoptosis, in the kidney; and enhancing renal hypoxia inducible factor 1-α expression. Proteomic analysis revealed that the treatment with xenon downregulated renal NLRP3 inflammasome-mediated cellular signaling. Similarly, xenon was effective in improving renal pathology and function in a spontaneous LN model in female NZB/W F1 mice. Thus, xenon may have a therapeutic role in treating LN but further studies are warranted to determine applicability to patients.

Overexpression of COX6B1 protects against I/R‑induced neuronal injury in rat hippocampal neurons

Cerebrovascular disease (CVD) is one of the leading causes of mortality worldwide. The role of cytochrome c oxidase subunit 6B1 (COX6B1) in the central nervous system remains unclear. The present study aimed to analyze the role of COX6B1 in rat hippocampal neurons extracted from fetal rats. The subcellular localization of the neuron‑specific marker microtubule‑associated protein 2 was detected by immunofluorescence assay. Cell viability was assessed using a cell counting kit, and the levels of apoptosis and cytosolic Ca2+ were analyzed by flow cytometry. The expression levels of the molecular factors downstream to COX6B1 were determined using reverse transcription‑quantitative polymerase chain reaction and western blotting. Reoxygenation following oxygen‑glucose deprivation (OGD) decreased cell viability and the expression levels of COX6B1 in a time‑dependent manner, and 60 min of reoxygenation was identified as the optimal time period for establishing an ischemia/reperfusion (I/R) model. Overexpression of COX6B1 was demonstrated to reverse the viability of hippocampal neurons following I/R treatment. Specifically, COX6B1 overexpression decreased the cytosolic concentration of Ca2+ and suppressed neuronal apoptosis, which were increased following I/R treatment. Furthermore, overexpression of COX6B1 increased the protein expression levels of apoptosis regulator BCL‑2 and mitochondrial cytochrome c (cyt c), and decreased the protein expression levels of apoptosis regulator BCL2‑associated X and cytosolic cyt c in I/R model cells. Collectively, the present study results suggested that COX6B1 overexpression may reverse I/R‑induced neuronal damage by increasing the viability of neurons, by decreasing the cytosolic levels of Ca2+ and by suppressing apoptosis. These results may facilitate the development of novel strategies for the prevention and treatment of CVD.