Low-dose lithium feeding increases the SERCA2a-to-phospholamban ratio, improving SERCA function in murine left ventricles.

NEW FINDINGS: What is the central question of this study? Inhibition of glycogen synthase kinase-3 (GSK3) has been shown to improve cardiac SERCA2a function. Lithium can inhibit GSK3, but therapeutic doses used in treating bipolar disorder can have toxic effects. It has not been determined whether subtherapeutic doses of lithium can improve cardiac SERCA function. What is the main finding and its importance? Using left ventricles from wild-type mice, we found that subtherapeutic lithium feeding for 6 weeks decreased GSK3 activity and increased cardiac SERCA function compared with control-fed mice. These findings warrant the investigation of low-dose lithium feeding in preclinical models of cardiomyopathy and heart failure to determine the therapeutic benefit of GSK3 inhibition. ABSTRACT: The sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) pump is responsible for regulating calcium (Ca2+ ) within myocytes, with SERCA2a being the dominant isoform in cardiomyocytes. Its inhibitor, phospholamban (PLN), acts by decreasing the affinity of SERCA for Ca2+ . Changes in the SERCA2a:PLN ratio can cause Ca2+ dysregulation often seen in patients with dilated cardiomyopathy and heart failure. The enzyme glycogen synthase kinase-3 (GSK3) is known to downregulate SERCA function by decreasing the SERCA2a:PLN ratio. In this study, we sought to determine whether feeding mice low-dose lithium, a natural GSK3 inhibitor, would improve left ventricular SERCA function by altering the SERCA2a:PLN ratio. To this end, male wild-type C57BL/6J mice were fed low-dose lithium via drinking water (10 mg kg-1  day-1 LiCl for 6 weeks) and left ventricles were harvested. GSK3 activity was significantly reduced in LiCl-fed versus control-fed mice. The apparent affinity of SERCA for Ca2+ was also increased (pCa50 ; control, 6.09 ± 0.03 versus LiCl, 6.26 ± 0.04, P < 0.0001) along with a 2.0-fold increase in SERCA2a:PLN ratio in LiCl-fed versus control-fed mice. These findings suggest that low-dose lithium supplementation can improve SERCA function by increasing the SERCA2a:PLN ratio. Future studies in murine preclinical models will determine whether GSK3 inhibition via low-dose lithium could be a potential therapeutic strategy for dilated cardiomyopathy and heart failure.

Quantitative analysis of brain NADH in the presence of hemoglobin using microfiber spectrofluorometry: a pre-calibration approach.

Dysfunction of mitochondria links a variety of central nervous system disorders and other neurodegenerative diseases. The primary respiratory chain substrate reduced-form nicotinamide adenine dinucleotide (NADH) is an important regulator of respiratory chain function in mitochondria and, because of its fluorescent properties, has been used to assess mitochondrial pathophysiology in cells and tissues. However, assessment of changes in tissue NADH has been limited to qualitative analysis primarily because hemoglobin (Hb) interferes with NADH fluorescence measurements by absorbing both excitation and emission light. This report presents a computer-assisted approach to estimate tissue NADH and Hb concentrations quantitatively at the same time. The method is based on a two-dimensionally interpolated database model that is calibrated by fluorescence emission spectra with known-value standard chemical solutions. Quantitative concentrations for NADH and Hb can be determined by the corresponding known-value spectral data that have the minimum error to the sample spectrum obtained from an experiment. Repeatability and reliability tests are also presented in this report. Results demonstrate that this method can feasibly quantify the NADH content regardless of the Hb background in living hippocampal cells during hypoxia, suggesting that it has the potential to be applied to in vivo experiments in the future.

[The applications of SERS to labeled immunoassay].

Combining the high sensitivity of a variety of readout technologies with the specific adsorption between antibody and antigen, labeled immunoassay possesses a remarkable effect in microanalysis. The discovery and confirmation of Surface enhanced Raman Spectroscopy (SERS) made Raman spectroscopy a powerful tool in many research fields, especially in biomedicine. In this report, the authors describe the applications of the high sensitivity of SERS to labeled immunoassay, and introduce some work in this field by our laboratory.

[Study of the factors effecting surface-enhanced Raman scattering reporter-labeled immunogold colloids].

The applications of the high sensitivity of Surface-Enhanced Raman Spectroscopy (SERS) in labeled immunoassay have proved to be very useful. In the sandwich structure of "immobile antibody-antigen-labeled antibody", the authors prepared the labeled antibody by attaching gold nanoparticles, which was first labeled with molecule that had SERS signal, to the antibody. In this article, colloids were labeled with Raman reporter thiophenol through S-Au bond on gold and formed surface-enhanced Raman scattering (SERS) reporter-labeled gold colloids. Then, goat anti-rat antibody was adsorbed onto the reporter-labeled gold colloids and formed reporter-labeled immunogold colloids. This paper studied factors affecting FT-SERS reporter-labeled immunogold colloids such as the sizes of gold particles, the amount of thiophenol in gold colloids and processing time, and whether goat anti-rat antibody would influence the SERS of reporter-labeled gold colloids.

[Confocal microprobe Raman spectroscopic study of electrochemical reduction of benzene on a platinum electrode].

The electrochemical reduction of benzene on a smooth Pt electrode has been studied by confocal microprobe Raman spectroscopy. The results show that benzene can be reduced directly to cyclohexane, which is insoluble in water, adhered onto the electrode surface to form the third phase. After the drops have been formed on the electrode surface, the relative concentration of benzene to cyclohexane in the drops will rather increase with prolonging the time at a certain electrode potential, although it decreases with the negative shift of the electrode potential at first.

Differentiation of oligodendrocyte progenitor cells from human embryonic stem cells on vitronectin-derived synthetic peptide acrylate surface.

Human embryonic stem cell (hESC)-derived oligodendrocyte progenitor cells (OPCs) are being studied for cell replacement therapies, including the treatment of acute spinal cord injury. Current methods of differentiating OPCs from hESCs require complex, animal-derived biological extracellular matrices (ECMs). Defined, low-cost, robust, and scalable culture methods will need to be developed for the widespread deployment and commercialization of hESC-derived cell therapies. Here we describe a defined culture system that uses a vitronectin-derived synthetic peptide acrylate surface (VN-PAS; commercially available as Corning(®) Synthemax(®) surface) in combination with a defined culture medium for hESC growth and differentiation to OPCs. We show that synthetic VN-PAS supports OPC attachment and differentiation, and that hESCs grown on VN-PAS are able to differentiate into OPCs on VN-PAS. Compared to OPCs derived from hESCs grown on ECM of animal origin, higher levels of NG2, a chondroitin sulfate proteoglycan expressed by OPCs, were observed in OPCs differentiated from H1 hESCs grown on VN-PAS, while the expression levels of Nestin and PDGFRα were comparable. In summary, this study demonstrates that synthetic VN-PAS can replace complex, animal-origin ECM to support OPC differentiation from hESCs.

Synthetic peptide-acrylate surfaces for long-term self-renewal and cardiomyocyte differentiation of human embryonic stem cells.

Human embryonic stem cells (hESCs) have two properties of interest for the development of cell therapies: self-renewal and the potential to differentiate into all major lineages of somatic cells in the human body. Widespread clinical application of hESC-derived cells will require culture methods that are low-cost, robust, scalable and use chemically defined raw materials. Here we describe synthetic peptide-acrylate surfaces (PAS) that support self-renewal of hESCs in chemically defined, xeno-free medium. H1 and H7 hESCs were successfully maintained on PAS for over ten passages. Cell morphology and phenotypic marker expression were similar for cells cultured on PAS or Matrigel. Cells on PAS retained normal karyotype and pluripotency and were able to differentiate to functional cardiomyocytes on PAS. Finally, PAS were scaled up to large culture-vessel formats. Synthetic, xeno-free, scalable surfaces that support the self-renewal and differentiation of hESCs will be useful for both research purposes and development of cell therapies.

[CH4 absorption and its affecting factors in a wheat field with conservation tillage].

In order to understand the relationships between CH4 fluxes and its affecting factors in a wheat field with conservation tillage, the CH4 fluxes in two wheat fields, one with conservation tillage and the another with conventional tillage, were measured in situ by static chamber-GC method, with soil temperature and soil moisture and inorganic nitrogen contents determined at the same time. The results showed that these two fields had an obvious and similar seasonal variation pattern of CH4 fluxes, but the average and seasonal CH4 absorption fluxes differed significantly. In the growth period of wheat, the fields were the sink of CH4, and the CH4 absorption fluxes was in the order of conventional tillage with no straw returning (CN) > conventional tillage with straw returning (CS) > subsoiling with straw returning (PS) > harrowing with straw returning (HS) > rotary tillage with straw returning (RS) > no tillage with straw covered (NS). Comparing with conventional tillage, conservation tillage reduced the CH4 absorption fluxes. In conservation tillage, the CH4 absorption fluxes was positively correlated with soil temperature but negatively correlated with soil moisture content; while in conventional tillage, the CH4 absorption fluxes had no significant correlations with the two factors. In all treatments, there was a significant negative correlation between CH4 absorption fluxes and soil NH4+ -N content.

Spectroscopic studies of mitochondrial NADH fluorescence signals in brain slices.

Dysfunction of mitochondria links a variety of central nervous system (CNS) disorders and other neurodegenerative diseases. The primary respiratory chain substrate reduced form nicotinamide adenine dinucleotide (NADH) is an important regulator of respiratory chain function in mitochondria and, because of its fluorescent properties, has been used to assess mitochondrial pathophysiology in cells and tissues. However, assessment of changes in tissue NADH has been limited to qualitative analysis primarily because hemoglobin (Hb) interferes with NADH fluorescence measurements by absorbing both excitation and emission light. This study presents a computer-assisted approach to estimate brain tissue NADH and Hb concentrations quantitatively at the same time. The method is based on a two-dimensionally interpolated database model that is calibrated by fluorescence emission spectra with known-value standard chemical solutions. Quantitative concentrations for NADH and Hb can be determined by the corresponding known-value spectral data that have the minimum error to the sample spectrum obtained from an experiment. Repeatability and reliability tests are also presented in this report. Results demonstrate that this method can feasibly quantify the NADH content regardless of the Hb background in living hippocampal cells during hypoxia, suggesting that it has potential to be applied to in vivo experiments in the future.