Expression of recombinant myostatin propeptide pPIC9K-Msp plasmid in Pichia pastoris

Myostatin propeptide can inhibit the biological activity of myostatin protein and promote muscle growth. To express myostatin propeptide in vitro with a higher biological activity, we performed codon optimization on the sheep myostatin propeptide gene sequence, and mutated aspartic acid-76 to alanine based on the codon usage bias of Pichia pastoris and the enhanced biological activity of myostatin propeptide mutant. Modified myostatin propeptide gene was cloned into the pPIC9K plasmid to form the recombinant plasmid pPIC9K-Msp. Recombinant plasmid pPIC9K-Msp was transformed into Pichia pastoris GS115 by electrotransformation. Transformed cells were screened, and methanol was used to induce expression. SDS-PAGE and western blotting were used to verify the successful expression of myostatin propeptide with biological activity in Pichia pastoris, providing the basis for characterization of this protein.

Experimental infection of pregnant rabbits with hepatitis E virus demonstrating high mortality and vertical transmission

A high mortality rate of approximately 20% in pregnant women with hepatitis E has been reported in previous studies. However, other studies showed no difference between pregnant and nonpregnant women in the severity of hepatitis E. To determine the effects of HEV infection on pregnancy, we successfully established HEV infection in six pregnant rabbits (PR) and six nonpregnant rabbits (NPR) with a rabbit HEV isolate, taking three PR and one NPR without HEV infection as controls. Tests for HEV RNA by RT-PCR, anti-HEV antibodies by ELISA and HEV antigen via immunohistochemistry and histopathology were carried out. Two of six infected PR miscarried and three of the remaining four PR died which may be attributed to severe liver necrosis caused by HEV infection. Moreover, vertical transmission was found to be associated with the replication of HEV in placenta, indicated by the presence of HEV RNA and antigen in placenta from the infected PR. Our findings strongly suggest that HEV infection could lead to adverse outcomes in pregnancy and vertical transmission, suggesting the necessity for pregnant women at risk of HEV infection to be vaccinated.

Diabetes mellitus is associated with breast cancer: systematic review, meta-analysis, and in silico reproduction

AIM

Breast cancer (BrCa) and diabetes mellitus (DM) are two major heath problems in women and the general population. This study explores the association between DM and breast cancer patients' survival outcomes, as well as the potential therapeutic merits of metformin.

METHODS

To explore the association between DM and BrCa, we performed systematic literature search in EMBASE (www.embase.com) and MEDLINE (www.ncbi.nlm.nih.gov/pubmed) from January 1960 to April 2014 and systematically identified clinical studies that assessed the association between BrCa mortality and DM. The NCBI Gene Expression Omnibus (GEO) database was analyzed to identify micro-RNA change in BrCa cells treated by metformin, a common drug for DM worldwide.

RESULTS

Twenty studies were selected for the meta-analysis, of which 16 reported all-cause mortality and 12 reported cancer specific death. During our inclusion period, the cohorts encompassed a total of 2,645,249 patients including more than 207,832 DM patients. Pre-existing DM was associated with a 37% increase of all-cause mortality risk for women with BrCa (HR=1.37; 95%CI: 1.34-1.41; P=0.02). DM was in general associated with a 17% increased risk for BrCa mortality in women (HR=1.17; 95%CI: 1.11-1.22; P<0.01). The GEO analysis revealed downregulation of a series of pro-tumorigenic micro-RNAs following metformin treatment, which was in part restored by DICER knockdown.

CONCLUSION

Women with DM are at higher risk of BrCa-specific and all-cause mortality after initial breast cancer diagnosis. BrCa patients with DM could possibly benefit from metformin treatment via DICER mediation.

miR-199a impairs autophagy and induces cardiac hypertrophy through mTOR activation

Basal autophagy is tightly regulated by transcriptional and epigenetic factors to maintain cellular homeostasis. Dysregulation of cardiac autophagy is associated with heart diseases, including cardiac hypertrophy, but the mechanism governing cardiac autophagy is rarely identified. To analyze the in vivo function of miR-199a in cardiac autophagy and cardiac hypertrophy, we generated cardiac-specific miR-199a transgenic mice and showed that overexpression of miR-199a was sufficient to inhibit cardiomyocyte autophagy and induce cardiac hypertrophy in vivo. miR-199a impaired cardiomyocyte autophagy in a cell-autonomous manner by targeting glycogen synthase kinase 3β (GSK3β)/mammalian target of rapamycin (mTOR) complex signaling. Overexpression of autophagy related gene 5 (Atg5) attenuated the hypertrophic effects of miR-199a overexpression on cardiomyocytes, and activation of autophagy using rapamycin was sufficient to restore cardiac autophagy and decrease cardiac hypertrophy in miR-199a transgenic mice. These results reveal a novel role of miR-199a as a key regulator of cardiac autophagy, suggesting that targeting miRNAs controlling autophagy as a potential therapeutic strategy for cardiac disease.

Impact of caffeine on β cell proliferation and apoptosis under the influence of palmitic acid

We examined the influence of caffeine on the proliferation and apoptosis of β cells cultured in vitro in the presence of the free fatty acid palmitic acid (PA). Different concentrations of caffeine (1-100 mM) and free fatty PA were added to cultured β cells. The MTT assay was used to analyze cell proliferative activity; flow cytometry was used to measure apoptosis and calculate the apoptosis rate. Compared with the blank control group, cells cultured with 500 mM PA for 24, 48, 72, and 96 h showed inhibition of pancreatic β cell proliferative activity. In the 10 and 25 mM caffeine groups cultured for 48, 72, and 96 h, β cell proliferative activity was much higher than that in the 500 mM PA group. The apoptosis rate in the 500 mM PA group was 40.55 ± 20.33%, which was higher than that in the blank control group. The apoptosis rates in the 10 and 25 mM caffeine group and the PA group were 19.12 ± 10.56 and 20.97 ± 9.75%, respectively, which was lower than that in the 500 mM PA group. At some concentrations, caffeine can improve free fatty PA levels and guide pancreatic β cell proliferation inhibition and cell apoptosis.

Fibronectin chorused cohesion between endothelial progenitor cells and mesenchymal stem cells of mouse bone marrow

Endothelial progenitor cells (EPCs) could function as niche cells to promote self&mdash;renewal of mesenchymal stem cells (MSCs) in the mouse bone marrow. Cohesion was the basis of the two cells to display their biological functions to each other. In this study, we investigated the mechanism of cohesion between MSCs and EPCs. And demonstrated that fibronectin (FN) in EPCs activated the integrin &#945;5&#946;1 of MSCs and further mediated cell-cell cohesion. Integrin &#945;5&#946;1 and its FN ligand played critical roles not only in single&mdash;cell line adhesion, but also in adhesion between stem and niche cells. This novel finding is important to understand the cross&mdash;talk between MSCs and their niche cells.

A fluorescent probe for H2S in vivo with fast response and high sensitivity

In this work, a fluorescent probe has been designed and synthesized that could be applied for monitoring and imaging exogenous or endogenous H₂S in live MCF-7 cells and in live mice with the fastest response.

Mechanism of action of ethylene sulfite and vinylene carbonate electrolyte additives in LiNi1/3Mn1/3Co1/3O2/graphite pouch cells: electrochemical, GC-MS and XPS analysis

The SEI films formation/composition were dominated by VC resulting in better electrochemical performance of LiNi_1/3Mn_1/3Co_1/3O₂ (NMC)/graphite pouch cells.

Application of acoustic radiation force impulse imaging (ARFI) in quantitative evaluation of neonatal brain development

OBJECTIVE

This study aims to quantitatively evaluate the effect of acoustic radiation force impulse imaging (ARFI) in neonatal brain development.

MATERIALS AND METHODS

The authors observed 41 neonatal brain different tissues by using traditional two-dimensional gray scale ultrasound and color Doppler flow imaging and frequency spectrum ultrasound. After that they used ARFI to quantitative evaluate white and gray matter of neonatal different tissues in brain with different gestational ages. They also used new technical index: virtual touch tissue quantification (VTQ) to evaluate elastic changes of brain tissues.

RESULTS

Different tissues in brain had different elastic numerical values. Neonatal with different gestational ages had different elastic numerical values. The more gestational ages were, the more the elastic numerical values. Elastic numerical values between preterm and full-term infants were different. Elastic numerical values of full-term infants were higher than preterm infants.

CONCLUSION

ARFI provides a new quantitative index to evaluate neonatal brain development. It increases objectivity and reliability of clinical analysis. Ultrasound was a noninvasive examination method, safe, simple, and convenient, and it has more usefulness of ARFI in quantitative evaluation of neonatal brain development.

Regulatory effect of iron regulatory protein-2 on iron metabolism in lung cancer

Iron metabolism plays an important role in the pathogenesis of lung cancer. This study aimed to investigate the effect of gene silencing of iron regulatory protein-2 (IRP2) on mRNA and protein expression of transferrin (Tf), transferrin receptor (TfR), and ferritin (Fn) in A549 lung cancer cells. A549 cells were cultured and divided into a liposome control group, a liposome + oligonucleotide (SCODN) control group, and a Lipofectamine + antisense oligonucleotide (ASODN) group. RT-PCR and Western blotting were used to detect mRNA and protein expression of Tf, TfR, and Fn. We found no significant change in Tf mRNA expression among the 3 groups (P = 0.078). TfR and Fn mRNA expressions in the ASODN group notably decreased compared to the liposome and SCODN groups (P < 0.01). IRP2 and TfR protein expressions in the ASODN group were significantly lower than in the liposome or SCODN groups (P < 0.05), whereas no significant change in Tf protein expression was observed between the 3 groups (P = 0.088). Fn protein expression in the ASODN group was significantly higher than in the liposome or SCODN group (P < 0.05). IRP2 can regulate the expression of TfR and Fn by changing its own protein expression and thereby regulate iron metabolism.

Randomised clinical trial: L-ornithine-L-aspartate reduces significantly the increase of venous ammonia concentration after TIPSS

BACKGROUND

Use of TIPSS is associated with increases in ammonia concentration and hepatic encephalopathy (HE) risk. L-ornithine-L-aspartate (LOLA) is effective in reducing ammonia concentration.

AIM

To evaluate the effects of LOLA on venous ammonia concentration after TIPSS.

METHODS

The included patients were randomised to receive LOLA or no-LOLA treatment for 7 days. Fasting and post-prandial venous ammonia levels were the primary outcomes. Psychometric performance, post-TIPSS HE, and liver and renal function were assessed as secondary outcomes.

RESULTS

Of 133 cirrhotic patients who received successful TIPSS between November 2011 and June 2012, 40 met the inclusion criteria and were randomised to the LOLA (n = 21) or control (n = 19) groups. Change in fasting ammonia significantly favoured the LOLA group at days 4 (P = 0.001) and 7 (P = 0.003). Changes in post-prandial ammonia concentration significantly favoured the LOLA group at days 1, 4 and 7 as well. During the study period, patients in the LOLA group had better improvement in psychometric tests than those in the control group. Overt HE during treatment was observed in one patient in the LOLA group and three patients in the control group (P = 0.331). There were no differences in complications, adverse events or mortality between the two groups.

CONCLUSIONS

Prophylactic use of LOLA infusion after TIPSS is safe and effective in significantly reducing the increase of venous ammonia concentration, and can benefit the patient's mental status as well.

Topological surface state in the Kondo insulator samarium hexaboride

Topological invariants of electron wavefunctions in condensed matter reveal many intriguing phenomena. A notable example is provided by topological insulators, which are characterized by an insulating bulk coexisting with a metallic boundary state. Although there has been intense interest in Bi-based topological insulators, their behaviour is complicated by the presence of a considerable residual bulk conductivity. Theories predict that the Kondo insulator system SmB6, which is known to undergo a transition from a Kondo lattice metal to a small-gap insulator state with decreasing temperature, could be a topological insulator. Although the insulating bulk and metallic surface separation has been demonstrated in recent transport measurements, these have not demonstrated the topologically protected nature of the metallic surface state. Here we report thickness-dependent transport measurements on doped SmB6, and show that magnetic and non-magnetic doping results in contrasting behaviour that supports the conclusion that SmB6 shows virtually no residual bulk conductivity.