Cardiac fibroblast miR-27a may function as an endogenous anti-fibrotic by negatively regulating Early Growth Response Protein 3 (EGR3).

Pathological myocardial fibrosis and hypertrophy occur due to chronic cardiac stress. The microRNA-27a (miR-27a) regulates collagen production across diverse cell types and organs to inhibit fibrosis and could constitute an important therapeutic avenue. However, its impact on hypertrophy and cardiac remodelling is less well-known. We employed a transverse aortic constriction (TAC) murine model of left ventricular pressure overload to investigate the in vivo effects of genetic miR-27a knockout, antisense inhibition of miR-27a-5p and fibroblast-specific miR-27a knockdown or overexpression. In silico Venn analysis and reporter assays were used to identify miR-27a-5p's targeting of Early Growth Response Protein 3 (Egr3). We evaluated the effects of miR-27a-5p and Egr3 upon transforming growth factor-beta (Tgf-ß) signalling and secretome of cardiac fibroblasts in vitro. miR-27a-5p attenuated TAC-induced cardiac fibrosis and myofibroblast activation in vivo, without a discernible effect on cardiac myocytes. Molecularly, miR-27a-5p inhibited transforming growth factor-beta (Tgf-ß) signalling and pro-fibrotic protein secretion in cardiac fibroblasts in vitro through suppressing the pro-fibrotic transcription factor Early Growth Response Protein 3 (Egr3). This body of work suggests that cardiac fibroblast miR-27a may function as an endogenous anti-fibrotic by negatively regulating Egr3 expression.

Stable Superhydrophobic Ceramic-Based Carbon Nanotube Composite Desalination Membranes.

Membrane distillation (MD) is a promising process for the treatment of highly saline wastewaters. The central component of MD is a stable porous hydrophobic membrane with a large liquid-vapor interface for efficient water vapor transport. A key challenge for current polymeric or hydrophobically modified inorganic membranes is insufficient operating stability, resulting in some issues such as wetting, fouling, flux, and rejection decline. This study presents an overall conceptual design and application strategy for a superhydrophobic ceramic-based carbon nanotube (CNT) desalination membrane having specially designed membrane structures with unprecedented operating stability and MD performance. Superporous and superhydrophobic surface structures with CNT networks are created after quantitative regulation of in situ grown CNT. The fully covered CNT layers (FC-CNT) exhibit significantly improved thermally and superhydrophobically stable properties under an accelerated stability test. Due to the distinctive structure of the superporous surface network, providing a large liquid-vapor superhydrophobic interface and interior finger-like macrovoids, the FC-CNT membrane exhibits a stable high flux with a 99.9% rejection of Na+, outperforming existing inorganic membranes. Under simple and nondestructive electrochemically assisted direct contact MD (e-DCMD), enhanced antifouling performance is observed. The design strategy is broadly applicable to be extended toward fabrication of high performance membranes derived from other ceramic or inorganic substrates and additional applications in wastewater and gas treatment.

Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs)-Based Composite Membranes: A Review.

Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs)-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization techniques of CNTs, and then reviews the fabrication methods for CNTs-based composite membranes in detail. The applications of CNTs-based composite membranes in water treatment are comprehensively reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metal ions and emerging pollutants as well as membrane separation coupled with assistant techniques. Furthermore, the future direction and perspective for CNTs-based composite membranes are also briefly outlined.

[Screening of citrullinated proteins in ten tumor cell lines].

OBJECTIVE: The conversion of arginine into citrulline, termed citrullination, has important consequences for the structure and function of proteins. The present study aimed to identify novel citrullinated proteins in 10 tumor cell lines by 2-D Western blotting (2-D WB). METHODS: Two identical two-dimensional electrophoresis (2-DE) gels were prepared using extracts from ten cultured human tumor cell lines: ECA(esophageal cancer cells), HEPG2 (hepatocellular carcinoma cells), SKOV3 (ovarian cancer cells), MCF-7 (breast cancer cells), H292 (lung mucoepidermoid carcinoma cells), HeLa (cervical cancer cells), Lovo (colon cancer cells), OS-RC (renal cell carcinoma cells), PANC-1 (pancreatic cancer cells), and SGC (gastric cancer cells). The expression profiles on one 2-DE gels were trans-blotted to PVDF membranes, and the blots were then probed with an anti-citrulline antibody. By comparing the 2-DE profile with the parallel 2-D WB profile at a global level, protein spots with immuno-signals were collected from the second 2-DE gel and identified using mass spectrometry. Immunoprecipitation was used to verify the expression and citrullination of the targeted proteins in the tumor cell lines. RESULTS: 2-D WB and mass spectrometry identified citrullinated ENO1 (α-enolase), HSP60 (heat shock protein 60), KRT8 (keratin 8), TUBB (tubulin beta), TCRß (T cell receptor ß chain), VIME (vimentin) and PDI in these cell lines. Immunoprecipitation analyses verified the expression and citrullination of ENO1, HSP60, KRT8, and TUBB in the total protein lysates of the tumor cell lines. CONCLUSION: The citrullination of proteins ENO1, HSP60, KRT8, and TUBB suggests a new mechanism in the tumorigenic process.

Differential effects of Akt1 signaling on short- versus long-term consequences of myocardial infarction and reperfusion injury.

A specific role for Akt1 in events following myocardial infarction (MI) and ischemia/reperfusion (I/R) injury is not known. We aimed to determine whether Akt1 deletion in in vivo mouse models of MI and after ischemia I/R injury would alter myocyte survival, cardiac function, and fibrosis. Akt1(+/+) and Akt1(-/-) mice were subjected to MI and I/R, followed by assessment of downstream signaling events and functional consequences. Although no difference in infarct size following short-term MI was observed between Akt1(+/+) and Akt1(-/-) mice, I/R caused substantially more cardiomyocyte apoptosis and tissue damage in Akt1(-/-) mice compared with Akt1(+/+). Importantly, these effects were reversed upon pretreatment with GSK-3 inhibitor SB415286. Counterintuitively, Akt1(-/-) hearts exhibited improved cardiac function following long-term MI compared with Akt1(+/+) and were associated with reduced fibrosis in the left ventricle (LV). Our results demonstrate that Akt1-mediated inhibition of GSK-3 activity is critical for cardioprotection following I/R. However, in the long term, Akt1 contributes to fibrosis in post-MI hearts and might exacerbate cardiac dysfunction showing dichotomous role for Akt1 in cardiac remodeling after MI. Our data suggest that better understanding of the Akt1/GSK-3 pathway may provide insights for better therapeutic strategies in post-MI tissues.

Interference with akt signaling protects against myocardial infarction and death by limiting the consequences of oxidative stress.

The intricacy of multiple feedback loops in the pathways downstream of Akt allows this kinase to control multiple cellular processes in the cardiovascular system and precludes inferring consequences of its activation in specific pathological conditions. Akt1, the major Akt isoform in the heart and vasculature, has a protective role in the endothelium during atherosclerosis. However, Akt1 activation may also have detrimental consequences in the cardiovascular system. Mice lacking both the high-density lipoprotein receptor SR-BI (scavenger receptor class B type I) and ApoE (apolipoprotein E), which promotes clearance of remnant lipoproteins, are a model of severe dyslipidemia and spontaneous myocardial infarction. We found that Akt1 was activated in these mice, and this activation correlated with cardiac dysfunction, hypertrophy, and fibrosis; increased infarct area; cholesterol accumulation in macrophages and atherosclerosis; and reduced life span. Akt1 activation was associated with inflammation, oxidative stress, accumulation of oxidized lipids, and increased abundance of CD36, a major sensor of oxidative stress, and these events created a positive feedback loop that exacerbated the consequences of oxidative stress. Genetic deletion of Akt1 in this mouse model resulted in decreased mortality, alleviation of multiple complications of heart disease, and reduced occurrence of spontaneous myocardial infarction. Thus, interference with Akt1 signaling in vivo could be protective and improve survival under dyslipidemic conditions by reducing oxidative stress and responses to oxidized lipids.

[Expression of cysteine rich 61 and vascular endothelial growth factor genes in patients with myelodysplastic syndromes and their relationship.].

OBJECTIVE: To explore the expression of Cysleine-rich 61(Cyr61) gene in the different subtypes of myelodysplastic syndromes (MDS), and the significance of Cyr61 in the genesis progression, and transformation of MDS and the relationship between Cyr61 and vascular endothelial grown factor (VEGF). METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical S-P were used to detect mRNA and protein expressions of Cyr61 and VEGF in bone marrow mononuclear cells (BMMNC) from 28 MDS, 12 acute myeloid leukemia (AML) patients, and 10 normal volunteers. RESULTS: Expressions of Cyr61 and VEGF were higher in MDS and AML patients than in controls (P < 0.05). The expressions of Cyr61 and VEGF were significantly higher in high risk group (0.3998 +/- 0.2647, 0.4775 +/- 0.1342) than that in low risk MDS group (0.2213 +/- 0.1465, 0.2872 +/- 0.2341) (P < 0.05), but no significant difference between high risk MDS and AML patients. Expressions of Cyr61 and VEGF protein were higher in MDS patients than in normal controls (P < 0.05), and were significantly higher in high risk MDS group \[(38.7 +/- 2.9)%, (43.2 +/- 2.7)%\] than in low risk group \[(31.4 +/- 3.1)%, (33.5 +/- 3.4)%\] (P < 0.05). Expressions of Cyr61 and VEGF were significantly correlated (r = 0.8762, P < 0.01). CONCLUSION: Cyr61 and VEGF may play a role in the angiogenesis and pathogenesis of MDS.

Transplantation of embryonic stem cells into the infarcted mouse heart: formation of multiple cell types.

Initial studies have suggested that transplantation of embryonic stem (ES) cells following myocardial infarction (MI) in animal models is beneficial; however, the mechanism of benefit is largely unknown. The present study investigated the fate of mouse ES cells transplanted post-MI to determine if the ES cells give rise to the range of major cell types present in the native myocardium. MI was produced by coronary artery ligation in C57BL/6 mice. Two different mouse ES cell lines, expressing eGFP and beta-galactosidase, respectively, were tested. Post-MI intramyocardial injection of 3 x 10(4) ES cells was compared to injection of media alone. Histochemistry and immunofluorescence were used to track the transplanted ES cells and identify the resulting cell types. Echocardiography assessed the cardiac size and function in a blinded fashion. Two weeks post-MI, engraftment of the transplanted ES cells was demonstrated by eGFP or beta-galactosidase-positive cells in the infarct region without evidence for tumor formation. Co-immunolabeling demonstrated that the transplanted ES cells had become cardiomyocytes, vascular smooth muscle, and endothelial cells. Echocardiographic analysis showed that ES cell transplantation resulted in reduced post-MI remodeling of the heart and improved cardiac function. In conclusion, transplanted mouse ES cells can regenerate infarcted myocardium in part by becoming cardiomyocytes, vascular smooth muscle, and endothelial cells that result in an improvement in cardiac structure and function. Therefore, ES cells hold promise for myocardial cellular therapy.

The human TAZ gene complements mitochondrial dysfunction in the yeast taz1Delta mutant. Implications for Barth syndrome.

Barth syndrome is a genetic disorder that is caused by different mutations in the TAZ gene G4.5. The yeast gene TAZ1 is highly homologous to human TAZ, and the taz1Delta mutant has phospholipid defects similar to those observed in Barth syndrome cells, including aberrant cardiolipin species and decreased cardiolipin levels. Subcellular fractionation studies revealed that Taz1p is localized exclusively in mitochondria, which supports the theory that tafazzins are involved in cardiolipin remodeling. Because cardiolipin plays an important role in respiratory function, we measured the energy transformation and osmotic properties of isolated mitochondria from the taz1Delta mutant. Energy coupling in taz1Delta mitochondria was dependent on the rate of oxidative phosphorylation, as coupling was diminished when NADH was used as a respiratory substrate but was unaffected when ethanol was the substrate. Membrane stability was compromised in taz1Delta mitochondria exposed to increased temperature and hypotonic conditions. Mitochondria from taz1Delta also displayed decreased swelling in response to ATP, which induces the yeast mitochondrial unspecific channel, and to alamethicin, a membrane-disrupting agent. Coupling was measured in taz1Delta cells containing different splice variants of the human TAZ gene. Only the variant that restores wild type cardiolipin synthesis (lacking exon 5) restored coupling in hypotonic conditions and at elevated temperature. These findings may shed light on the mitochondrial deficiencies observed in Barth syndrome.

Absence of cardiolipin results in temperature sensitivity, respiratory defects, and mitochondrial DNA instability independent of pet56.

Cardiolipin (CL) is a dimeric phospholipid localized primarily in the mitochondrial membrane. Previous studies have shown that yeast cells containing a disruption of CRD1, the structural gene encoding CL synthase, exhibit temperature-sensitive colony formation and multiple mitochondrial defects. A recent report (Zhang, M., Su, X., Mileykovskaya, E., Amoscato, A. A., and Dowhan, W. (2003) J. Biol. Chem. 278, 35204-35210) suggested that defects associated with CL deficiency may result from the reduced expression of PET56 in crd1 Delta mutant backgrounds and should be reevaluated. In the current study, we present evidence that CL deficiency leads to mitochondrial DNA instability, loss of viability, and defects in oxidative phosphorylation at elevated temperatures. The observed mutant phenotypes are characteristic of crd1 Delta mutant cells of both PET56 and pet56 backgrounds and are complemented by an episomal copy of CRD1 but not by expression of the PET56 gene. Phosphatidylglycerol is elevated in crd1 Delta mutant cells when grown in the presence of fermentable and non-fermentable carbon sources, although the extent of the increase is higher in nonfermentable medium. An increase in the ratio of phosphatidylethanolamine to phosphatidylcholine was also apparent in the mutant. These findings demonstrate that CRD1, independent of PET56, is required for optimal mitochondrial function and for an essential cellular function at elevated temperatures.