IL-15Rα deficiency leads to mitochondrial and myofiber differences in fast mouse muscles

The purpose of this study was to determine mitochondrial changes in fast muscles from interleukin-15 receptor alpha knockout (IL-15RαKO) mice. We tested the hypothesis that fast muscles from IL-15RαKO mice would have a greater mitochondrial density and altered internal structure compared to muscles from control mice. In fast muscles from IL-15RαKO mice, mitochondrial density was 48% greater with a corresponding increase in mitochondrial DNA content. Although there were no differences in the relative size of isolated mitochondria, internal complexity was lower in mitochondria from IL-15RαKO mice. These data support an increase in mitochondrial biogenesis and provide direct evidence for a greater density and altered internal structure of mitochondria in EDL muscles deficient in IL-15Rα.     

Hopeahainol A attenuates memory deficits by targeting β‐amyloid in APP/PS1 transgenic mice

Increasing evidence demonstrates that amyloid beta (Aβ) elicits mitochondrial dysfunction and oxidative stress, which contributes to the pathogenesis of Alzheimer's disease (AD). Identification of the molecules targeting Aβ is thus of particular significance in the treatment of AD. Hopeahainol A (HopA), a polyphenol with a novel skeleton obtained from Hopea hainanensis, is potentially acetylcholinesterase‐inhibitory and anti‐oxidative in H₂O₂‐treated PC12 cells. In this study, we reported that HopA might bind to Aβ_1–42 directly and inhibit the Aβ_1–42 aggregation using a combination of molecular dynamics simulation, binding assay, transmission electron microscopic analysis and staining technique. We also demonstrated that HopA decreased the interaction between Aβ_1–42 and Aβ‐binding alcohol dehydrogenase, which in turn reduced mitochondrial dysfunction and oxidative stress in vivo and in vitro. In addition, HopA was able to rescue the long‐term potentiation induction by protecting synaptic function and attenuate memory deficits in APP/PS1 mice. Our data suggest that HopA might be a promising drug for therapeutic intervention in AD.     

Highly sensitive chemiluminescence immunoassay on chitosan membrane modified paper platform using TiO2 nanoparticles/multiwalled carbon nanotubes as label

A highly sensitive chemiluminescence (CL) immunoassay was incorporated into a low‐cost microfluidic paper‐based analytical device (μ‐PAD) to fabricate a facile paper‐based CL immunodevice (denoted as μ‐PCLI). This μ‐PCLI was constructed by covalently immobilizing capture antibody on a chitosan membrane modified μ‐PADs, which was developed by simple wax printing methodology. TiO₂ nanoparticles coated multiwalled carbon nanotubes (TiO₂/MWCNTs) were synthesized as an amplification catalyst tag to label signal antibody (Ab₂). After sandwich‐type immunoreactions, the TiO₂/MWCNTs were captured on the surface of μ‐PADs to catalyze the luminol‐p‐iodophenol‐H₂O₂ CL system, which produced an enhanced CL emission. Using prostate‐specific antigen as a model analyte, the approach provided a good linear response range from 0.001 to 20 ng/mL with a low detection limit of 0.8 pg/mL under optimal conditions. This μ‐PCLI showed good reproducibility, selectivity and stability. The assay results of prostate‐specific antigen in clinical serum samples were in good agreement with that obtained by commercially used electrochemiluminescence methods at the Cancer Research Center of Shandong Tumor Hospital (Jinan, Shandong Province, China). This μ‐PCLI could be very useful to realize highly sensitive, qualitative point‐of‐care testing in developing or developed countries. Copyright © 2013 John Wiley & Sons, Ltd.     

Rational design of microRNA–siRNA chimeras for multifunctional target suppression

MicroRNAs (miRNAs) are involved in a variety of human diseases by simultaneously suppressing many gene targets. Thus, the therapeutic value of miRNAs has been intensely studied. However, there are potential limitations with miRNA-based therapeutics such as a relatively moderate impact on gene target regulation and cellular phenotypic control. To address these issues, we proposed to design new chimeric small RNAs (aiRNAs) by incorporating sequences from both miRNAs and siRNAs. These aiRNAs not only inherited functions from natural miRNAs, but also gained new functions of gene knockdown in an siRNA-like fashion. The improved efficacy of multifunctional aiRNAs was demonstrated in our study by design and testing of an aiRNA that inherited the functions of both miR-200a and an AKT1-targeting siRNA for simultaneous suppression of cancer cell motility and proliferation. The general principles of aiRNA design were further validated by engineering new aiRNAs mimicking another miRNA, miR-9. By regulating multiple cellular functions, aiRNAs could be used as an improved tool over miRNAs to target disease-related genes, thus alleviating our dependency on a limited number of miRNAs for the development of RNAi-based therapeutics.     

A New Coronary Retroinfusion Technique in theRat Infarct Model: Transjugular Cardiac Vein Catheterization

Cell delivery via the retrograde coronary route boasts less vessel embolism, myocardial injury, and arrhythmogenicity when compared with those via antegrade coronary administration or myocardial injection. However, conventional insertion into the coronary sinus and consequent bleeding complication prevent its application in small animals. To overcome the complication of bleeding, we described a modified coronary retroinfusion technique via the jugular vein route in rats with myocardial infarction (MI). A flexible wire with a bent end was inserted into the left internal jugular vein and advanced slowly along the left superior vena cava. Under direct vision, the wire was run into the left cardiac vein by rotating the wire and changing the position of its tip. A fine tube was then advanced along the wire to the left cardiac vein. This modified technique showed less lethal hemorrhage than the conventional technique. Retroinfusion via transjugular catheter enabled efficient fluid or cell dissemination to the majority areas of the free wall of the left ventricle, covering the infarcted anterior wall. In conclusion, transjugular cardiac vein catheterization may make retrocoronary infusion a more safe and practical route for delivering cell, drug, and gene therapy into the infarcted myocardium of rats.     

The production of phytolith‐occluded carbon in China's forests: implications to biogeochemical carbon sequestration

The persistent terrestrial carbon sink regulates long‐term climate change, but its size, location, and mechanisms remain uncertain. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content–biogenic silica content transfer function obtained from our investigation, in combination with published silica content and aboveground net primary productivity (ANPP) data of leaf litter and herb layer in China's forests, we estimated the production of phytolith‐occluded carbon (PhytOC) in China's forests. The present annual phytolith carbon sink in China's forests is 1.7 ± 0.4 Tg CO₂ yr ^{? 1}, 30% of which is contributed by bamboo because the production flux of PhytOC through tree leaf litter for bamboo is 3–80 times higher than that of other forest types. As a result of national and international bamboo afforestation and reforestation, the potential of phytolith carbon sink for China's forests and world's bamboo can reach 6.8 ± 1.5 and 27.0 ± 6.1 Tg CO₂ yr^?1, respectively. Forest management practices such as bamboo afforestation and reforestation may significantly enhance the long‐term terrestrial carbon sink and contribute to mitigation of global climate warming.