Oncoprotein HBXIP induces PKM2 via transcription factor E2F1 to promote cell proliferation in ER-positive breast cancer

We have reported that hepatitis B X-interacting protein (HBXIP, also termed LAMTOR5) can act as an oncogenic transcriptional co-activator to modulate gene expression, promoting breast cancer development. Pyruvate kinase muscle isozyme M2 (PKM2), encoded by PKM gene, has emerged as a key oncoprotein in breast cancer. Yet, the regulatory mechanism of PKM2 is still unexplored. Here, we report that HBXIP can upregulate PKM2 to accelerate proliferation of estrogen receptor positive (ER+) breast cancer. Immunohistochemistry analysis using breast cancer tissue microarray uncovered a positive association between the expression of HBXIP and PKM2. We also discovered that PKM2 expression was positively related with HBXIP expression in clinical breast cancer patients by real-time PCR assay. Interestingly, in ER+ breast cancer cells, HBXIP was capable of upregulating PKM2 expression at mRNA and protein levels in a dose-dependent manner, as well as increasing the activity of PKM promoter. Mechanistically, HBXIP could stimulate PKM promoter through binding to the -779/-579 promoter region involving co-activation of E2F transcription factor 1 (E2F1). In function, cell viability, EdU, colony formation, and xenograft tumor growth assays showed that HBXIP contributed to accelerating cell proliferation through PKM2 in ER+ breast cancer. Collectively, we conclude that HBXIP induces PKM2 through transcription factor E2F1 to facilitate ER+ breast cancer cell proliferation. We provide new evidence for the mechanism of transcription regulation of PKM2 in promotion of breast cancer progression.

[Surface morphology and surface properties of Ti and TiZr implant materials]

Objective: To investigate the effects of hydrophilic treatment on the surface morphology and surface properties of pure titanium and titanium-zirconium alloy implants, and to provide reference for the studies of implant surface modification. Methods: The pure titanium group, the hydrophilic pure titanium group, the titanium zirconium alloy group and the hydrophilic titanium-zirconium alloy group were prepared by sandblasting and acid-etching or hydrophilic sandblasting and acid-etching, (11 specimens in each group). The surface morphology and surface properties of four types of titanium specimens were analyzed by surface contact angle meter, scanning electron microscope (SEM), optical profilometer, atomic force microscope (AFM) and Raman spectrometer. Results: The surface contact angles of hydrophilic pure titanium and hydrophilic titanium-zirconium alloy were 1.6°±0.3° and 1.5°±0.2°, and the surface contact angles of pure titanium and titanium-zirconium alloy were 101.4°±4.6° and 96.2°±3.0°, respectively. SEM showed that the nano-protrusions on the surface of pure titanium and titanium-zirconium alloys were less or even absent, while the nano-protrusions on the surface of hydrophilic pure titanium and hydrophilic titanium-zirconium alloys were relatively more; the nano-protrusions on the surface of hydrophilic pure titanium surface were small and dense relatively, but the nano-protrusions of the hydrophilic titanium-zirconium alloy had large diameters and were dispersed relatively. The optical profiler and AFM showed that the surface roughness of hydrophilic pure titanium and hydrophilic titanium-zirconium alloy was significantly higher than that of pure titanium and titanium-zirconium alloy (P<0.05). Raman spectroscopy showed that only the amorphous TiO(2) was present on the surface of the pure titanium group, while the rutile TiO(2) characteristic peak was observed in the other three groups, but the lateral inhomogeneity was observed. After Raman shift 610 cm(-1), the Raman spectra of four groups were similar. Conclusions: Hydrophilic sandblasting and acid-etching treatment can improve the surface hydrophilicity and surface roughness of pure titanium and titanium zirconium alloy, and improve the surface properties of pure titanium and titanium zirconium alloy implants.

miRNA-7a-2-3p Inhibits Neuronal Apoptosis in Oxygen-Glucose Deprivation (OGD) Model

Neuronal apoptosis is a major pathological hallmark of the neonatal hypoxic-ischemic brain damage (HIBD); however, the role of miR-7a-2-3p in the regulation of HIBD remains unknown. The purpose of this study was to explore the possible roles of miR-7a-2-3p in brain injury using a hypoxia-ischemia model in rats and oxygen-glucose deprivation (OGD) model in vitro. Firstly, we established the hypoxia-ischemia (HI) model and verified the model using Zea Longa scores and MRI in rats. Next, the changes of miR-7a-2-3p were screened in the ischemic cortex of neonatal rats by qRT-PCR at 12, 48, and 96 h after HIBD. We have found that the expression of miR-7a-2-3p in the HI rats decreased significantly, compared with the sham group (P < 0.01). Then, we established the OGD model in PC12 cells, SH-SY5Y cells and primary cortical neurons in vitro and qRT-PCR was used to confirm the changes of miR-7a-2-3p in these cells after the OGD. In order to determine the function of miR-7a-2-3p, PC12 cells, SH-SY5Y cells and rat primary cortical neurons were randomly divided into normal, OGD, mimic negative control (mimic-NC) and miR-7a-2-3p groups. Then, Tuj1+ (neuronal marker) staining, TUNEL assay (to detect apoptotic cells) and MTT assay (to investigate cell viability) were performed. We have found that the number of PC12 cells, SH-SY5Y cells and cortical neurons in the miR-7a-2-3p groups increased significantly (P < 0.01) in comparison to the OGD groups. The survival of cortical neurons in the miR-7a-2-3p group was improved markedly (P < 0.01), while the apoptosis of neurons in the miR-7a-2-3p group was significantly decreased (P < 0.01), compared with the normal group. Lastly, we investigated the target genes of miR-7a-2-3p by using the prediction databases (miRDB, TargetScan, miRWalk, and miRmap) and verified the target genes with qRT-PCR in the HI rats. Bioinformatics prediction showed that Vimentin (VIM), pleiomorphic adenoma gene 1(PLAG1), dual specificity phosphatase 10 (DUSP10), NAD(P)H dehydrogenase, quinone 1 (NQO1) and tumor necrosis factor receptor superfamily member 1B (TNFRSF1B) might be the targets of miR-7a-2-3p and the qRT-PCR confirmed that VIM increased in the HI rats (P < 0.01). In conclusion, miR-7a-2-3p plays a crucial role in the hypoxic-ischemic injury, and is associated with regulation of VIM.

[Effect of hydrogen-rich saline on the CD4(+) CD25(+) Foxp3(+) Treg cells of allergic rhinitis guinea pigs model]

Objective: To explore the effect of hydrogen-rich saline on the CD4(+) CD25(+) Foxp3(+) Treg cells in a guinea pig model of allergic rhinitis (AR) and investigate the underling anti-inflammatory mechanism. Methods: Using random number table, eighteen guinea pigs were divided into three groups (control group/AR group/HRS group, n=6 of each group). AR guinea pig model was built with ovalbumin and aluminum. The guinea pigs were injected with hydrogen-rich saline (HRS group) for ten days after sensitation. And control group was injected with equal normal saline at the same time. Number of sneezes, degree of runny nose and nasal rubbing movements were scored. Peripheral blood eosinophil count was recorded. The content of interleukin 10(IL-10) and transforming growth factor β (TGF-β) in the serum were detected by enzyme-linked immunosorbent assay (ELISA). Immunohistochemical method was taken to detect IL-10 and TGF-β in nasal mucosa. The proportion of CD4(+) CD25(+) Foxp3(+) T cells in the CD4(+) T cells of spleen and peripheral blood were determined with flow cytometry. SPSS 17.0 software was used to analyze the data. Results: There was significant difference in symptom scores among them. The scores of AR group preceded control group, and HRS could decrease the scores of AR ((6.29±1.79) vs (1.01±0.71), (4.50±0.84) vs (6.29±1.79), F=24.725, all P<0.05). The highest number of eosinophils in the peripheral blood belonged to control group, and the number of eosinophils were dramatically reduced after HRS administration ((0.41±0.05)×10(9)/L vs (0.25±0.03 )×10(9)/L, (0.32±0.03)×10(9)/L vs (0.41±0.05)×10(9)/L, F=70.05, all P<0.05). The content of IL-10 and TGF-β in control group is peak ((86.88±17.17) pg/ml, (598.28±72.70) pg/ml, respectively), and compared with AR group, HRS also increased the expression of IL-10 and TGF-β of peripheral blood ((72.54±11.75) pg/ml vs (53.49±10.07) pg/ml, (530.23±57.15) pg/ml vs (482.69±65.96) pg/ml, F value was 28.357, 14.128, respectively, all P<0.05). The proportion of CD4(+) CD25(+) Foxp3(+) Treg cells in controls exceeded HRS group and AR group (1.81%±0.10%, 1.29%±0.74%, respectively), and HRS treatment increased the ratio of CD4(+) CD25(+) Foxp3(+) Treg cells than AR group of peripheral blood ((1.50%±0.11%) vs (1.15%±0.11%), F=168.96, P<0.05). But there was no significant diferences in splene tissue ((1.01%±0.08%) vs (0.98%±0.09%), F=97.381, P>0.05). Conclusion: Both the number and the cytokine secretion of CD4(+) CD25(+) Foxp3(+) Treg cells are decreased in AR group, HRS may inhibit inflammatory response and ameliorate AR via improving the number and the cytokine secretion.

Methicillin-resistant Staphylococcus aureus alters cell wall glycosylation to evade immunity

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of difficult-to-treat, often fatal infections in humans^1,2. Most humans have antibodies against S. aureus, but these are highly variable and often not protective in immunocompromised patients³. Previous vaccine development programs have not been successful⁴. A large percentage of human antibodies against S. aureus target wall teichoic acid (WTA), a ribitol-phosphate (RboP) surface polymer modified with N-acetylglucosamine (GlcNAc)^5,6. It is currently unknown whether the immune evasion capacities of MRSA are due to variation of dominant surface epitopes such as those associated with WTA. Here we show that a considerable proportion of the prominent healthcare-associated and livestock-associated MRSA clones CC5 and CC398, respectively, contain prophages that encode an alternative WTA glycosyltransferase. This enzyme, TarP, transfers GlcNAc to a different hydroxyl group of the WTA RboP than the standard enzyme TarS⁷, with important consequences for immune recognition. TarP-glycosylated WTA elicits 7.5-40-fold lower levels of immunoglobulin G in mice than TarS-modified WTA. Consistent with this, human sera contained only low levels of antibodies against TarP-modified WTA. Notably, mice immunized with TarS-modified WTA were not protected against infection with tarP-expressing MRSA, indicating that TarP is crucial for the capacity of S. aureus to evade host defences. High-resolution structural analyses of TarP bound to WTA components and uridine diphosphate GlcNAc (UDP-GlcNAc) explain the mechanism of altered RboP glycosylation and form a template for targeted inhibition of TarP. Our study reveals an immune evasion strategy of S. aureus based on averting the immunogenicity of its dominant glycoantigen WTA. These results will help with the identification of invariant S. aureus vaccine antigens and may enable the development of TarP inhibitors as a new strategy for rendering MRSA susceptible to human host defences.

Brain-Derived Glia Maturation Factor β Participates in Lung Injury Induced by Acute Cerebral Ischemia by Increasing ROS in Endothelial Cells

Brain damage can cause lung injury. To explore the mechanism underlying the lung injury induced by acute cerebral ischemia (ACI), we established a middle cerebral artery occlusion (MCAO) model in male Sprague-Dawley rats. We focused on glia maturation factor β (GMFB) based on quantitative analysis of the global rat serum proteome. Polymerase chain reaction, western blotting, and immunofluorescence revealed that GMFB was over-expressed in astrocytes in the brains of rats subjected to MCAO. We cultured rat primary astrocytes and confirmed that GMFB was also up-regulated in primary astrocytes after oxygen-glucose deprivation (OGD). We subjected the primary astrocytes to Gmfb RNA interference before OGD and collected the conditioned medium (CM) after OGD. We then used the CM to culture pulmonary microvascular endothelial cells (PMVECs) acquired in advance and assessed their status. The viability of the PMVECs improved significantly when Gmfb was blocked. Moreover, ELISA assays revealed an elevation in GMFB concentration in the medium after OGD. Cell cultures containing recombinant GMFB showed increased levels of reactive oxygen species and a deterioration in the state of the cells. In conclusion, GMFB is up-regulated in astrocytes after ACI, and brain-derived GMFB damages PMVECs by increasing reactive oxygen species. GMFB might thus be an initiator of the lung injury induced by ACI.

The expression of circulating tumor cells in peripheral blood of patients with non-small cell lung cancer and its detection

This study aimed to investigate the expression of circulating tumor cells (CTCs) in peripheral blood and relevant detection methods as well as the clinical values of determination of CTCs for the diagnosis of non-small cell lung cancer (NSCLC). Peripheral blood specimens were acquired from the patients with NSCLC who came to the Thoracic Surgery Department of Jining No.1 People’s Hospital, Shandong, China for the first visit between January 2015 and November 2016. Whether there was metastasis of CTCs or not was determined by detecting the number of epithelial cell adhesion molecules (EpCAM) which had expression in the CTCs of the peripheral blood with fluorescence polymerase chain reaction. Moreover, the correlation between the expression level of EpCAM of patients with NSCLC during postoperative adjuvant treatment and the efficacy of adjuvant therapy was initially explored. The expression level of EpCAM of the NSCLC patients was remarkably different to that of the patients with benign lung diseases. The expression level of EpCAM of the patients with NSCLC was notably different with that of the healthy volunteers. The expression level of EpCAM of the patients with NSCLC was much higher than that of patients with benign lung diseases and the volunteers. Moreover, the expression level of NSCLC at stages I, II and IIIA had significant differences; the expression level of EpCAM tended to increase as the stage of NSCLC developed. The expression level of EpCAM in CTCs of peripheral blood can be regarded as a reference for the early diagnosis and detection of NSCLC before and after surgery.

[Clinical presentations of neuromyelitis optica spectrum disorders with ultra-longitudinally extensive transverse myelitis]

Objective: To analyze the clinical presentations of neuromyelitis optica spectrum disorders (NMOSD) with ultra-longitudinally extensive transverse myelitis (uLETM), in order to improve the diagnostic accuracy of this disorder. Methods: Twenty-two uLETM patients was recruited and retrospectively analyzed for general clinical characteristics, laboratory tests and MRI characteristics, as well as therapeutic. Results: (1)The Male-to-female ratio was 1∶6. The median onset age was 31 years old. The duration from the first relapse to the onset was 5.5 months. (2)The positive rate of serum water channel aquaporin-4 antibody (AQP4-Ab) in the acute phase was 86.4%. The positive rate of cerebrospinal fluid (CSF) AQP4-Ab in the acute phase was 69.2%. The positive rate of autoimmune antibodies was 72.7%. There was a remarkable difference (Z=-12.632, P=0.000) in serum AQP4-Ab titer levels between with the acute and remission period (median titer of 1∶244.78 to 1∶139.63). There was a remarkable difference (Z=-20.161, P=0.000) in geometric mean of serum AQP4-Ab titer levels between with CSF AQP4-Ab positive (1∶289.8) and negative (1∶36.2). (3)63.6% of the uLETM patients had 10-15 contiguous segments, 31.8% had 16-19 contiguous segments and 4.5% had whole spinal cord affected. 72.7% of the lesions of uLETM were sliver. The detection rate of optic nerve lesion by MRI was 63.6% and brain sliver lesions was seen in 63.6% of the patients.(4) All patients improved after treatment with high-dose glucocorticoids (GCs) in the acute phase. 15 cases treated with long-term oral administration of low-dose GCs in remission stage of NMOSD. 6 cases treated with mycophenolate mofetil. 1 case treated with intravenous immunoglobulins. Conclusions: NMOSD with uLETM is predominantly seen in young woman. The high risk period of relapse is 5.5 months after the onset. A high portion of NMOSD patients with uLETM have serum and CSF AQP4-Ab in acute phase. The therapy of GCs is recommended in acute phase. Combination of GCs with immunosuppressant can achieve stable and satisfactory effect in remission period of NMOSD.

1,3-Dibromo-5,5-dimethylhydantoin as promoter for glycosylations using thioglycosides

1,3-Dibromo-5,5-dimethylhydantoin (DBDMH), an inexpensive, non-toxic and stable reagent, is a competent activator of thioglycosides for glycosidic bond formation. Excellent yields were obtained when triflic acid (TfOH) or trimethylsilyl trifluoromethanesulfonate (TMSOTf) were employed as co-promoters in solution or automated glycan assembly on solid phase.

Family of Ricinus communis Monosaccharide Transporters and RcSTP1 in Promoting the Uptake of a Glucose-Fipronil Conjugate

Enhancing the systemic distribution of a bioactive compound by exploiting the vascular transport system of a plant presents a means of reducing both the volume and frequency of pesticide/fungicide application. The foliar uptake of the glucose-fipronil conjugate N-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine (GTF) achieved in castor bean (Ricinus communis) and its transport via the phloem are known to be mediated by monosaccharide transporter(s) [MST(s)], although neither the identity of the key MST(s) involved nor the mechanistic basis of its movement have yet to be described. On the basis of homology with Arabidopsis thaliana sugar transporters, the castor bean genome was concluded to harbor 53 genes encoding a sugar transporter, falling into the eight previously defined subfamilies INT, PMT, VGT, STP, ERD6, pGlucT, TMT, and SUT. Transcriptional profiling identified the product of RcSTP1 as a candidate for mediating GTF uptake, because this gene was induced by exposure of the plant to GTF. When RcSTP1 was transiently expressed in onion epidermis cells, the site of RcSTP1 deposition was shown to be the plasma membrane. A functional analysis based on RcSTP1 expression in Xenopus laevis oocytes demonstrated that its product has a high affinity for GTF. The long-distance root-to-shoot transport of GTF was enhanced in a transgenic soybean chimera constitutively expressing RcSTP1.

Identification of the epileptogenic zone of temporal lobe epilepsy from stereo-electroencephalography signals: A phase transfer entropy and graph theory approach

The aim of this research is to apply an approach based on phase transfer entropy (PTE) and graph theory to study the interactions between the stereo-electroencephalography (SEEG) activities recorded in multilobar origin, in order to evaluate their ability to detect the epileptogenic zone (EZ) of temporal lobe epilepsies (TLE). Forty-three patients were included in this retrospective study. Five to sixteen (median = 12) multilead electrodes were implanted per patient, and, for each patient, a sub-set of between 10 and 32 (median = 22) bipolar derivations was selected for analysis. The leads were classified into the onset leads (OLs), the early propagation leads (EPLs), and the rest of the leads (RLs). The results showed that a significantly different dynamic trend of the out/in ratio (more obvious in the gamma band) distinguishes the OLs from RLs in the 23 patients who were seizure-free not only during the ictal event (significant elevation), but also during the inter-,pre-, late-ictal periods, and especially in the post-ictal (sharp decline) state. However, in the 20 patients who were not-seizure-free, the differences between the OLs and RLs during the post-ictal period were not found in any frequency band. The dynamic trend was used to predict surgical outcome, and the results showed that the sensitivity was 91% and the specificity was 70%. In brief, this study indicates that our approach may add new and valuable information, providing efficient quantitative measures useful for localizing the EZ.

[The Improvement in the Primary Culture of Alveolar Epithelial Type of Rats]

OBJECTIVES

To improve the method of culturing and obtain purified alveolar epithelial type1 (AT1) cells of SD rats.

METHODS

1 d newborn SD rats were applied for cell culture and brains were decapitated for lung tissues obtaining after respiratory cessation. Collagenase1and DNase1 were used to digest and isolate cells. Then, cells were put into the plate coated with type1 rat tail collagen and different adherence was used to purify cells. Meanwhile, culture medium replacement was conducted after 48 h. The growth status was observed under an inverted microscope. Immunofluorescence including specific marker AQP5, SPC, BSI, Vimentin were used to identify cells.

RESULTS

2 d after incubation, the cells began to adhere to plate. At day 4 and 6, cells began to proliferate and exhibited a shape of spindle, cube and polygon. 8 d after incubation, the character of proliferation reached the highest and the cell viability was (87±8)% and purification was (87±5)%.

CONCLUSION

By modifying the methods of tissues harvest, isolation and culture, we can obtain AT 1 cells with high yield, good growth state and super purity.

[Improving Primary Culture of Pulmonary Microvascular Endothelial Cells of Rats]

OBJECTIVES

To improve the culturing method of pulmonary microvascular endothelial cells (PMEVCs) of SD rats.

METHODS

The culturing processes in regard to obtaining peripheral lung tissue, attaching tissue block,preparing medium and subculturing were modified.These included an injection of heparin sodium before anesthesia, abdominal bleeding, opening of chest when breathing stopped, improvement of operational details, reduction of pollution by adding penicillin and streptomycin, discard of tissues after 48 h of primary culturing, remove of fibroblasts by a second digestion, and identification of cells using a fluorescence microscope for binding with lectin from BSI (FITC-BSI).An inverted microscope was used to observe the morphological characteristics of PMEVCs.

RESULTS

Purified PMEVCs were obtained,which displayed a polygon or short fusiform, exhibiting a typical cobblestone-like morphology. The morphology of PMVECs turned into swirling or long fusiform following subculture or changes in culture conditions. The results of FITC-BSI assay showed that more than 90% cells were stained with green fluorescence.

CONCLUSIONS

Purified PMEVCs with a good growth state and subculture stability can be obtained using the modified method.

Association analysis between carcass weight and meat quality of Bamei pigs

A total of 48 crossbred Bamei pig carcasses were divided into three groups (A, 60-69 kg; B, 70-79 kg; and C, 80-90 kg) to investigate the influence of carcass weight on meat quality. The intramuscular fat content of the three groups increased from 2.20% (Group A) to 4.14% (Group C). Group B had higher drip loss (6.83%, P < 0.05) than the other two groups. Warner-Bratzler shear force decreased with increasing weight (61.16 > 51.63 > 43.64 N, P < 0.05). No significant differences were observed in meat color, cooking percentage, and water holding capacity among the three groups. The polyunsaturated fatty acids/saturated fatty acids ratio in group B (0.23) was significantly higher than that in the other two groups. In conclusion, our results suggested that a carcass weight of 70-79 kg is suitable for the production of Bamei pigs.

Identification of a Panax ginseng fruit fingerprint by HPLC-ESI-MS

Over many years, parts of Panax ginseng (root and rhizome) have been identified and applied for medical purposes as traditional Chinese herbal medicine. Recently, research has indicated that ginseng fruit also contains similar compounds and is as rich as the other parts of the ginseng. This discovery may dramatically improve the efficient of outputs derived from ginseng products. Here, a new technique combining high-performance liquid chromatography (HPLC) with electrospray ionization tandem mass spectrometry (ESI-MS) was employed to identify the fingerprint of P. ginseng fruit. Using HPLC, compounds that are important for medical purposes were extracted and purified. Combined with ESI-MS, the characteristic peaks (nine common peaks) of those compounds were identified, and the accuracy was confirmed by analysis using the Chromatographic Fingerprint Similarity Evaluation System (2004A edition). Overall, 15 batches of ginseng fruit had a similarity of more than 0.80, 13 batches of samples had a similarity between 0.97 and 0.99, and two batches had a similarity less than 0.90. The test solution and mobile phase selection was discussed. The HPLC-ESI-MS method can produce repeatable and reliable results and can be applied in the quality control of P. ginseng fruit.

Expression pattern of JMJD1C in oocytes and its impact on early embryonic development

Cell reprogramming mediated by histone methylation and demethylation is crucial for the activation of the embryonic genome in early embryonic development. In this study, we employed quantitative real-time polymerase chain reaction (qRT-PCR) to detect mRNA levels and expression patterns of all known histone demethylases in early germinal vesicle stage and in vitro-matured metaphase II (MII) oocytes (which are commonly used as donor cells for nuclear transfer). On screening, the Jumonji domain containing 1C (JMJD1C) gene had the highest level of expression and hence was used for subsequent experiments. We also found that JMJD1C was primarily expressed in the nucleus and showed relatively high levels of expression at the 2-cell, 4-cell, 8-cell, 16-cell, morula, and blastocyst stages of embryos developed from MII oocytes fertilized in vitro. Further, we knocked down the JMJD1C gene in MII oocytes using siRNA and monitored the cleavage of zygotes and development of early embryos after in vitro fertilization. The results showed that the zygote cleavage and blastocyst rates of the transfection group were reduced by 57.1 ± 0.07 and 50 ± 0.01% respectively, which were significantly lower than those of the negative control group (P < 0.05). These data suggest that JMJD1C plays a key role in the normal development of early bovine embryos. Our results also provide a theoretical basis for the investigation of the role and molecular mechanism of histone demethylation in the early development of bovine embryos.

EDAG positively regulates erythroid differentiation and modifies GATA1 acetylation through recruiting p300

Erythroid differentiation-associated gene (EDAG) has been considered to be a transcriptional regulator that controls hematopoietic cell differentiation, proliferation, and apoptosis. The role of EDAG in erythroid differentiation of primary erythroid progenitor cells and in vivo remains unknown. In this study, we found that EDAG is highly expressed in CMPs and MEPs and upregulated during the erythroid differentiation of CD34(+) cells following erythropoietin (EPO) treatment. Overexpression of EDAG induced erythroid differentiation of CD34(+) cells in vitro and in vivo using immunodeficient mice. Conversely, EDAG knockdown reduced erythroid differentiation in EPO-treated CD34(+) cells. Detailed mechanistic analysis suggested that EDAG forms complex with GATA1 and p300 and increases GATA1 acetylation and transcriptional activity by facilitating the interaction between GATA1 and p300. EDAG deletion mutants lacking the binding domain with GATA1 or p300 failed to enhance erythroid differentiation, suggesting that EDAG regulates erythroid differentiation partly through forming EDAG/GATA1/p300 complex. In the presence of the specific inhibitor of p300 acetyltransferase activity, C646, EDAG was unable to accelerate erythroid differentiation, indicating an involvement of p300 acetyltransferase activity in EDAG-induced erythroid differentiation. ChIP-PCR experiments confirmed that GATA1 and EDAG co-occupy GATA1-targeted genes in primary erythroid cells and in vivo. ChIP-seq was further performed to examine the global occupancy of EDAG during erythroid differentiation and a total of 7,133 enrichment peaks corresponding to 3,847 genes were identified. Merging EDAG ChIP-Seq and GATA1 ChIP-Seq datasets revealed that 782 genes overlapped. Microarray analysis suggested that EDAG knockdown selectively inhibits GATA1-activated target genes. These data provide novel insights into EDAG in regulation of erythroid differentiation.

Panax quinquefolium saponin attenuates cardiomyocyte apoptosis induced by thapsigargin through inhibition of endoplasmic reticulum stress

BACKGROUND

Endoplasmic reticulum (ER) stress-related apoptosis is involved in the pathophysiology of many cardiovascular diseases, and Panax quinquefolium saponin (PQS) is able to inhibit excessive ER stress-related apoptosis of cardiomyocytes following hypoxia/reoxygenation and myocardial infarction. However, the pathway by which PQS inhibits the ER stress-related apoptosis is not well understood. To further investigate the protective effect of PQS against ER stress-related apoptosis, primary cultured cardiomyocytes were stimulated with thapsigargin (TG), which is widely used to model cellular ER stress, and it could induce apoptotic cell death in sufficient concentration.

METHODS

Primary cultured cardiomyocytes from neonatal rats were exposed to TG (1 µmol/L) treatment for 24 h, following PQS pre-treatment (160 µg/mL) for 24 h or pre-treatment with small interfering RNA directed against protein kinase-like endoplasmic reticulum kinase (Si-PERK) for 6 h. The viability and apoptosis rate of cardiomyocytes were detected by cell counting kit-8 and flow cytometry respectively. ER stress-related protein expression, such as glucose-regulated protein 78 (GRP78), calreticulin, PERK, eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP) were assayed by western blotting.

RESULTS

Both PQS pre-treatment and PERK knockdown remarkably inhibited the cardiomyocyte apoptosis induced by TG, increased cell viability, decreased phosphorylation of both PERK and eIF2α, and decreased protein levels of both ATF4 and CHOP. There was no statistically significant difference between PQS pre-treatment and PERK knockdown in the cardioprotective effect.

CONCLUSIONS

Our data indicate that the PERK-eIF2α-ATF4-CHOP pathway of ER stress is involved in the apoptosis induced by TG, and PQS might prevent TG-induced cardiomyocyte apoptosis through a mechanism involving the suppression of this pathway. These findings provide novel data regarding the molecular mechanisms by which PQS inhibits cardiomyocyte apoptosis.

MicroRNA-34c targets TGFB-induced factor homeobox 2, represses cell proliferation and induces apoptosis in hepatitis B virus-related hepatocellular carcinoma

MicroRNAs (miRs) are short, non-coding RNAs with post-transcriptional regulatory functions. Previous studies have demonstrated that miR-34c is involved in diverse biological processes, including carcinogenesis. The aim of the present study was to investigate the role of miR-34c and its target genes in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Expression levels of miR-34c and its predicted target genes were measured. The target genes were validated by a luciferase assay. The effects of miR-34c restoration were evaluated by the detection of HBV antigens, cell proliferation and apoptosis in vitro, in addition to the tumor growth in vivo. The data demonstrated that miR-34c was downregulated in HBV-associated HCC clinical tissues and HCC cell lines compared with their corresponding controls. transforming growth factor-β-induced factor homeobox 2 (TGIF2), a transcription factor repressing transforming growth factor-β (TGFβ) signaling, was observed to be upregulated and was identified as a target gene of miR-34c. The restoration of miR-34c in HepG2.2.15 cells suppressed TGIF2 expression, HBV replication and viral antigen synthesis; inhibited cell proliferation; and induced apoptosis. miR-34c also inhibited tumor growth in a mouse model. The present study indicates that miR-34c may act as a tumor suppressor by targeting TGIF2 during HBV-associated hepatocellular carcinogenesis. miR-34c and TGIF2 may represent key regulatory factors, diagnostic markers and therapeutic targets for the prevention and treatment of HBV-associated HCC.

Calreticulin translocation aggravates endoplasmic reticulum stress-associated apoptosis during cardiomyocyte hypoxia/reoxygenation

Background:

Calreticulin (CRT) is major Ca²⁺-binding chaperone mainly resident in the endoplasmic reticulum (ER) lumen. Recently, it has been shown that non-ER CRT regulates a wide array of cellular responses. We previously found that CRT was up-regulated during hypoxia/reoxygenation (H/R) and this study was aimed to investigate whether CRT nuclear translocation aggravates ER stress (ERS)-associated apoptosis during H/R injury in neonatal rat cardiomyocytes.

Methods:

Apoptosis rate and lactate dehydrogenase (LDH) leakage in culture medium were measured as indices of cell injury. Immunofluorescence staining showed the morphological changes of ER and intracellular translocation of CRT. Western blotting or reverse transcription polymerase chain reaction was used to detect the expression of target molecules.

Results:

Compared with control, H/R increased apoptosis rate and LDH activity. The ER became condensed and bubbled, and CRT translocated to the nucleus. Western blotting showed up-regulation of CRT, Nrf2, activating transcription factor 4 (ATF4), CHOP and caspase-12 expression after H/R. Exogenous CRT overexpression induced by plasmid transfection before H/R increased cell apoptosis, LDH leakage, ER disorder, CRT nuclear translocation and the expression of ERS-associated molecules. However, administration of the ERS inhibitor, taurine, or CRT siRNA alleviated cell injury, ER disorder, and inhibited ERS-associated apoptosis.

Conclusions:

Our results indicated that during H/R stress, CRT translocation increases cell apoptosis and LDH leakage, aggravates ER disorder, up-regulates expression of nuclear transcription factors, Nrf2 and ATF4, and activates ERS-associated apoptosis.

Cytosolic calreticulin inhibits microwave radiation-induced microvascular endothelial cell injury through the integrin-focal adhesion kinase pathway

OBJECTIVE

To determine the effects of cytosolic CRT on MR-induced MMEC injury, and the underlying mechanism.

METHODS

MMECs were randomized into eight groups: control, AdCRT (infected with pAdCMV/V5-DEST-CRT adenovirus), stCRT (transfected with rCRT-siRNAs), Mock (transfected with scrambled siRNAs), MR (exposed to MR for six minutes), AdCRT + MR, stCRT + MR, and Mock + MR. The magnitude of cell injury were assessed by Annexin V-PI staining, LDH activity in culture medium, MMEC migration ability, ultrastructure and cytoskeletal stability. Subcellular colocalization of CRT and ConA or integrin were evaluated by immunocytochemistry. The mRNA and protein expression levels of target genes were examined by qRT-PCR and western blotting, respectively.

RESULTS

MR-induced cytotoxicity was dose-dependent. Overexpression of cytosolic CRT suppressed MR injury, shown as decreased cell apoptosis, reduced LDH activity, enhanced cell migration capability, and maintenance of ultrastructure and cytoskeleton integrity. Conversely, CRT deficiency aggravated MR-induced injury. Exposure of AdCRT MMECs to MR promoted membrane translocation of CRT and the interaction of CRT-integrin-α. Correlation analysis revealed that integrin-α expression or FAK phosphorylation was positively associated with cytosolic CRT expression.

CONCLUSIONS

Cytosolic CRT inhibits MR-induced MMEC injury through activation of the integrin-FAK pathway.

Effects of THAP11 on erythroid differentiation and megakaryocytic differentiation of K562 cells

Hematopoiesis is a complex process regulated by sets of transcription factors in a stage-specific and context-dependent manner. THAP11 is a transcription factor involved in cell growth, ES cell pluripotency, and embryogenesis. Here we showed that THAP11 was down-regulated during erythroid differentiation but up-regulated during megakaryocytic differentiation of cord blood CD34+ cells. Overexpression of THAP11 in K562 cells inhibited the erythroid differentiation induced by hemin with decreased numbers of benzidine-positive cells and decreased mRNA levels of α-globin (HBA) and glycophorin A (GPA), and knockdown of THAP11 enhanced the erythroid differentiation. Conversely, THAP11 overexpression accelerated the megakaryocytic differentiation induced by phorbol myristate acetate (PMA) with increased percentage of CD41+ cells, increased numbers of 4N cells, and elevated CD61 mRNA levels, and THAP11 knockdown attenuated the megakaryocytic differentiation. The expression levels of transcription factors such as c-Myc, c-Myb, GATA-2, and Fli1 were changed by THAP11 overexpression. In this way, our results suggested that THAP11 reversibly regulated erythroid and megakaryocytic differentiation.

[Optimization of conditions for human erythropoiesis in human-mouse xenotransplant model]

This study was purposed to investigate the conditions for improving human-mouse xenograft and the erythroid differentiation of human hematopoietic stem cells (HSC) in the xenotransplant model. The engraftments of different mouse strains (NOD/SCID or NOD/SCID/IL2rγ(null)), schemes of irradiation (single-time or 2-times radiation; Co(60)γ-ray or X-ray) and strategies of CB CD34(+) cells ex vivo culture time and lentivirus infection were compared. The results showed that at 4 weeks after transplantation, the ratio of hCD45 positive cells in bone marrow of NOD/SCID/IL2rγ(null) mice increased to (51.4 ± 13.9)%, and erythroid precursor could be detected. All of the mice receiving X-ray irradiation for 2 times (a dose of 1 Gy, then the second of 1.5 Gy, with an interval of 15 min) survived. Fresh isolated CB CD34(+) cells were cultured and infected with lentivirus for 72 h and then transplanted into receptor mouse. After 4 weeks, higher engraftment [hCD45 (51.4 ± 13.9)%] and better erythroid development [hCD71(+) GPA(+) (5.98 ± 3.46)%] were observed. It is concluded that NOD/SCID/IL2rγ(null) mice receiving X-ray irradiation for 2 times and were injected with fresh isolated CB CD34(+) cells cultured and infected with lentivirus ex vivo within 72 h show a better xenograft and erythroid development.