Conserved function of Pacific cod Caspase-3 in apoptosis

Cloning, Exogenous Expression and Function Analysis of Interferon–γ from Gadus macrocephalus

Interferon γ (IFN–γ) is now considered to be one of the key molecules in the regulation of innate and adaptive immunity. The function of IFN–γ is best described in humans, but less of IFN–γ in fish species has been described at protein level. In the present study, IFN–γ from Gadus macrocephalus (GmIFN–γ) has been examined in terms of bioinformatics, prokaryotic expression, yeast expression, antiviral activity and immune regulatory function. The cDNA of GmIFN–γ contains an open reading frame of 570 nucleotides, coding 189 amino acids. The mature protein contains a nuclear localization signal motif and an obvious IFN–γ signature sequence at the C-terminal. GmIFN–γ is very similar to that of Atlantic cod, with homology up to 89.89%, but less than 32% to other species. GmIFN–γ can be detected in the gills, spleen, intestine, brain and kidney. Interestingly, during early development, a strong signal of GmIFN–γ was not detected until 40 days post hatching. Prokaryotic expression plasmid pET–32a–GmIFN–γ was constructed, and the expression products in BL21 were confirmed by Mass Spectrometry. Meanwhile, the plasmid pGAPZA–GmIFN–γ with Myc tag was constructed and transmitted into Pichia pastoris yeast GS115, and the products were tested using Western blot. The purified GmIFN–γ from either BL21 or yeast has a strong antivirus (Spring viremia of carp virus) effect. The vector of pcDNA3.1–GmIFN–γ was expressed in EPC cell lines; high transcript levels of MHC class I chain-related protein A (MICA) gene were detected; and the exogenous GmIFN–γ protein could also induce MICA expression, indicating that GmIFN–γ could stimulate immune response. The yeast GS115 with GmIFN–γ protein, which is an inclusion body, was given to zebrafish orally, and the transcript of zebrafish IFN–γ was upregulated significantly; however, genes of the interferon type–I signal pathway were not well stimulated.

Synergistic inhibition of the growth of MDA‑MB‑231 cells in triple‑negative breast cancer by salinomycin combined with 17‑AAG and its mechanism

Salinomycin (SAL), a typical ion carrier antibiotic, inhibits tumor growth and metastasis by inducing apoptosis or autophagy in cancer or cancer stem cells and thus overcomes drug resistance. 17-allylamino-17-demethoxygeldanamycin (17-AAG), a heat shock protein Hsp90 competitive inhibitor, also has a role in inhibiting tumor development. However, their combination on the growth of breast cancer cells and its specific mechanism remains to be elucidated. The present study tested the influence of SAL and 17-AAG on cell growth, apoptosis and autophagy by MTT assays, Annexin V-FITC and propidium iodide double staining assay and immunoelectron microscopy. The influence of SAL and 17-AAG on proteomics was investigated by isobaric tag for relative and absolute quantitation. It was found that SAL combined with 17-AAG synergistically inhibited the cell growth and induced the apoptosis in a concentration-dependent manner, with the expression of caspase 3 and Bcl-2 were decreased while the expression of Bax was increased. In addition, SAL combined with 17-AAG inhibited autophagy, with the expression of microtubule-associated protein 1 light chain 3, Beclin1, p62 being decreased. Mechanistically, SAL combined with 17-AAG synergistically inhibited the reactive oxygen species/JNK signaling pathway. In conclusion, SAL combined with 17-AAG had a synergistic inhibitory effect on cell growth of breast cancer via inducing apoptosis and inhibiting autophagy. The present study might provide a new strategy for potential clinical application of SAL as a new anti-tumor drug especially as a drug combination with other molecular targeting therapeutics.

Evolutionary conservation of a regulative pathway of erythropoiesis in Poikilothermic vertebrates

Apoptosis, programmed cell death, plays a central role in haematopoiesis. Mature erythrocytes of non-mammalian vertebrates maintain a permanent nucleus; these cells can undergo apoptosis (eryptosis), as do other somatic cells of a given non-mammalian vertebrate. In this study, we have investigated the expression and subcellular distribution of Bcl-2, Bcl-X_L and Bax proteins in the maturation phases and after X-ray irradiation of nucleated erythrocytes of Torpedo marmorata and Caretta caretta and the effect of X-ray irradiation on nucleated circulating erythrocytes of Torpedo marmorata. The cellular distribution of proteins was detected in erythrocytes by using immunocytochemistry at light microscopy and immunoelectron microscopy. The electrophoretic separation and immunoblotting of pro- and anti-apoptotic proteins of immature and mature erythroid cells was performed too, after X-ray irradiation of torpedoes. The results of the immunocytochemical analyses show an increase, in the expression level of Bax in mature as compared to young erythrocytes and a corresponding decrease of Bcl-2 and Bcl-X_L. This maturation pattern of Bax, Bcl-2 and Bcl-X_L was abrogated in X-ray irradiated torpedo erythrocytes. On the basis of these observations, Bax, Bcl-2 and Bcl-X_L seems to play a role in the erythropoiesis of Torpedo marmorata Risso and in Caretta caretta. In conclusion, the same apoptotic proteins of somatic cells appear to be conserved in circulating nucleated erythrocytes thus suggesting to play a role in the maturation of these cells.

20(S)-Protopanaxadiol Alleviates Myocardial Ischemia/Reperfusion Injury in Rats Through Suppression of Oxidative Stress and Apoptosis

20(S)-protopanaxadiol (PPD) is an active natural product which is transformed from protopanaxadiol-type ginsenosides. The present study was conducted to evaluate the effects of PPD on myocardial ischemia/reperfusion (I/R) injury in a rat model. PPD (20mg/kg) or positive-control drug Diltiazem (10mg/kg) was administered daily for 7 days before left anterior descending I/R operation. After 2-hour reperfusion, changes of cardiac morphology, structure, and function were evaluated by HE staining and echocardiography. Myocardial infarct size was assessed using nitroblue tetrazolium staining. The activities of cardiac enzymes in serum were also evaluated. Cardiomyocyte apoptosis was detected using the terminal dUTP nick end labelling (TUNEL) assay. The extent of oxidative stress was evaluated according to the activities of superoxide dismutase (SOD) and glutathione per oxidase (GPx) and the levels of malondialdehyde (MDA). Western blot and immunohistochemistry were used to determine the expression of apoptosis associated proteins, including Bcl-2, Bax, cleaved Caspase-3, cleaved Caspase-9, and cytochrome C. According to the results, PPD reduced I/R‑induced increases in myocardial infarct size and improved cardiac function. Furthermore, PPD decreased cardiomyocyte apoptosis on TUNEL staining, which was verified by increased Bcl-2, and decreased expression of Bax, cytochrome C, cleaved Caspase-9, and cleaved Caspase-3 in I/R rat myocardium. Additionally, PPD reduced MDA levels and increased the anti-oxidative capacity by upregulating the activities of SOD and GPx. Taken together, the results suggest that PPD serves a protective role against oxidative stress and cardiomyocyte apoptosis during myocardial ischemia/reperfusion injury.

Fas/FasL of pacific cod mediated apoptosis

Fas and Fas ligand (FasL) pathway plays important roles in virus defense and cell apoptosis. In our previous work, nervous necrosis virus (NNV) was discovered in Pacific cod (Gadus macrocephalus), and the Fas ligand (PcFasL) was up-regulated when NNV outbreak, however, signal transmission of Fas/FasL in fish are still unclear. In the present study, Pacific cod Fas (PcFas), PcFasL and Fas-associating protein with a novel death domain (PcFADD) were characterized. The predicted protein of PcFas, PcFasL and PcFADD includes 333 aa, 90 aa and 93 aa, separately. 3-D models of PcFas, PcFasL and PcFADD were well constructed based on reported templates, respectively, even though the sequence homology with other fish is very low. The transcript levels of PcFas increased gradually from 15 day-post hatching (dph) to 75dph. PcFas was significantly up-regulated when cod larvae had NNV symptoms at 24dph, 37dph, 46dph, 69dph, and 77dph. Subcellular localization revealed that PcFasL was located in the cytoplasm, while PcFas was mainly located in the cell membrane. Exogenous expressed PcFasL of 900 μg/mL could kill the Epithelioma papulosum cyprinid (EPC) cells by MTT test, but low concentration has no effect on the cells. qPCR analysis showed that overexpression of PcFas could significantly up-regulate the expression of genes related to Fas/FasL signaling pathway, including bcl-2, bax, and RIP3, while overexpression of PcFasL significantly up-regulate the expression of caspase-3, caspase-9, and MLKL. Overexpression of PcFas or PcFasL could induce EPC apoptosis significantly by flow cytometry, which was consistent with the results of caspase-3 mRNA level increasing. The results indicated that NNV could induce apoptosis through Fas/FasL signal pathway.

Exosomal microRNA-22-3p alleviates cerebral ischemic injury by modulating KDM6B/BMP2/BMF axis

Background

Cerebral ischemia-reperfusion (I/R) injury, the most common form of stroke, has high mortality and often brings persistent and serious brain dysfunction among survivors. Administration of adipose-derived mesenchymal stem cells (ASCs) has been suggested to alleviate the I/R brain injury, but the mechanism remains uncharacterized. Here, we aimed at investigating the mechanism of ASCs and their extracellular vesicles (EVs) in the repair of or protection from I/R injury.

Methods

We established the middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation/reperfusion (OGD/RP) neuron model. ASCs or ASC-derived EVs (ASC-EVs) were co-cultured with neurons. RT-qPCR and Western blot analyses determined microRNA (miRNA)-22-3p, BMP2, BMF, and KDM6B expression in neurons upon treatment with ASC-EVs. Bioinformatics analysis predicted the binding between miR-22-3p and KDM6B. Using gain- and loss-of-function methods, we tested the impact of these molecules on I/R injury in vivo and in vitro.

Results

Treatment with ASCs and ASC-derived EVs significantly alleviated the I/R brain injury in vivo, elevated neuron viability in vitro, and decreased apoptosis. Interestingly, miR-22-3p was upregulated in ASC-EVs, and treatment with EV-miR-22-3p inhibitor led to increased apoptosis and decreased neuronal. Of note, miR-22-3p bound to and inhibited KDM6B, as demonstrated by dual-luciferase reporter gene assay and Western blot assay. Overexpression of KDM6B enhanced apoptosis of neurons in the OGD/RP model, and KDM6B bound to BMB2 and promoted its expression by binding to BMP2. Silencing of BMF reduced infarct volume and apoptosis in the stroke model.

Conclusion

Results support a conclusion that ASC-EV-derived miR-22-3p could alleviate brain ischemic injury by inhibiting KDM6B-mediated effects on the BMP2/BMF axis. These findings compelling indicate a novel treatment strategy for cerebral ischemic injury.