Long‐term repopulation of aged bone marrow stem cells using young Sca‐1 cells promotes aged heart rejuvenation

Reduced quantity and quality of stem cells in aged individuals hinders cardiac repair and regeneration after injury. We used young bone marrow (BM) stem cell antigen 1 (Sca‐1) cells to reconstitute aged BM and rejuvenate the aged heart, and examined the underlying molecular mechanisms. BM Sca‐1⁺ or Sca‐1^? cells from young (2–3 months) or aged (18–19 months) GFP transgenic mice were transplanted into lethally irradiated aged mice to generate 4 groups of chimeras: young Sca‐1⁺, young Sca‐1^?, old Sca‐1⁺, and old Sca‐1^?. Four months later, expression of rejuvenation‐related genes (Bmi1, Cbx8, PNUTS, Sirt1, Sirt2, Sirt6) and proteins (CDK2, CDK4) was increased along with telomerase activity and telomerase‐related protein (DNA‐PKcs, TRF‐2) expression, whereas expression of senescence‐related genes (p16^INK4a, P19^ARF, p27^Kip1) and proteins (p16^INK4a, p27^Kip1) was decreased in Sca‐1⁺ chimeric hearts, especially in the young group. Host cardiac endothelial cells (GFP^?CD31⁺) but not cardiomyocytes were the primary cell type rejuvenated by young Sca‐1⁺ cells as shown by improved proliferation, migration, and tubular formation abilities. C‐X‐C chemokine CXCL12 was the factor most highly expressed in homed donor BM (GFP⁺) cells isolated from young Sca‐1⁺ chimeric hearts. Protein expression of Cxcr4, phospho‐Akt, and phospho‐FoxO3a in endothelial cells derived from the aged chimeric heart was increased, especially in the young Sca‐1⁺ group. Reconstitution of aged BM with young Sca‐1⁺ cells resulted in effective homing of functional stem cells in the aged heart. These young, regenerative stem cells promoted aged heart rejuvenation through activation of the Cxcl12/Cxcr4 pathway of cardiac endothelial cells.     

Nuclear fast red‐based colorimetric sensors for sensitive and selective detection of Ag ions

The reduction of nuclear fast red (NFR) stain by sodium tetrahydroboron was catalyzed in the presence of silver ions (Ag⁺). The fluorescence properties of reduced NFR differed from that of NFR. The product showed fluorescence emission at 480 nm with excitation at 369 nm. Furthermore, the fluorescence intensity of the mixture increased strongly in the presence of Ag⁺ and Britton–Robinson buffer at pH 4.78. There was a good linear relationship between increased fluorescence intensity (ΔI) and Ag⁺ concentration in the range 5.0 × 10^?9 to 5.0 × 10^?8 M. The correlation coefficient was 0.998, and the detection limit (3σ/k) was 1.5 × 10^?9 M. The colour of the reaction system changed with variation in Ag⁺ concentration over a wide range. Based on the colour change, a visual semiquantitative detection method for recognition and sensing of Ag⁺ was developed for the range 1.0 × 10^?8 to 5.0 × 10^?4 M, with an indicator that was visible to the naked eye. Therefore, a sensitive, simple method for determination of Ag⁺ was developed. Optimum conditions for Ag⁺ detection, the effect of other ions and the analytical application of Ag⁺ detection of synthesized sample were investigated.     

Determination of oxytetracycline hydrochloride in milk and egg white samples using Ru(bipy)32+–Ce(SO4)2 chemiluminescence

A novel, rapid and sensitive chemiluminescence (CL) method for the determination of oxytetracycline hydrochloride (OTCH) is described in this paper. The presented method was based on the fact that OTCH could immensely enhance the CL of the reaction of cerium sulfate and tris(2,2‐bipyridyl) ruthenium (II) in acidic medium. Under optimal experimental conditions, CL intensity was favorably linear for OTCH in the range 5.0 × 10^?7 to 5.0 × 10^?5 g/ml, with a detection limit of 1.5 × 10^?7 g/ml (S/N = 3). The relative standard detection was 4.76% for 5.0 × 10^?6 g/ml (n = 11). This method was successfully applied to the analysis of OTCH in milk and egg white samples. According to the results of the kinetic curves for OTCH in the Ru(bipy)₃²⁺–Ce(SO₄)₂ CL system, together with CL and ultraviolet (UV)–visible spectra, the possible mechanism of the CL reaction is discussed briefly.     

The enhanced effect of supplemented lighting on nutrient removal by an aquatic vegetables (lettuce) purification system from rural domestic sewage

Abstract

Aquatic plant treatment system (APTS) is a widely used sewage purification technique; however, it requires a large area of land due to its long hydraulic retention time. In order to improve the economic value of APTS in the treatment of rural sewage, an aquatic vegetables (lettuce) purification system strengthened with a set of supplemented lighting was evaluated. The effect of supplemented lighting of blue and red light on lettuce growth and sewage purification was studied by batch experiments. The results showed that the lettuce growth and the removal rates of pollutants were enhanced by supplemented lighting, of which red light is superior to blue light, and the increase of red light intensity further promoted the growth of lettuce and the removal rate of pollutants. Supplementary light is a suitable method which could improve the purification effect of APTS in most weather conditions especially in countries where day-night light patterns change substantially between winter and summer. The results would be useful for the APTS design for treating rural domestic sewage.     

Upregulation of the p53-p21 pathway by G2019S LRRK2 contributes to the cellular senescence and accumulation of α-synuclein

Parkinson’s disease (PD) is characterized by the degeneration of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (LB) in neurons. α-Synuclein (αSyn) is a major component of LB and promote the PD pathogenesis via its accumulation by the impaired proteasomal or autophagic clearance. Numerous studies have revealed that the reduction of proteasome activity and autophagy is accelerated by cellular senescence. Leucine-rich repeat kinase 2 (LRRK2) contributes to PD progression and its most prevalent mutation, G2019S LRRK2, increases its activity. Our previous report has shown that the G2019S LRRK2 mutant promoted p53-induced p21 expression and neuronal cytotoxicity. The p53-p21 pathway plays a role in cellular senescence. We hypothesized that the loss of dopaminergic neurons by the stimulated p53-p21 pathway via the G2019S LRRK2 mutation might be associated with cellular senescence, thereby promoting the accumulation of αSyn. We confirmed that the ectopic expression of the phosphomimetic p53 mutant, p21, or G2019 in differentiated SH-SY5Y cells increased the following: 1) the expression of β-galactosidase, a marker of cellular senescence, and the activity of senescence-associated β-galactosidase, 2) endogenous αSyn protein level, but not its mRNA level, and 3) αSyn fibril accumulation in dSH-SY5Y via low proteasome and cathepsin D activities. Elevated oligomeric αSyn and the increase in β-galactosidase with induced p21 were observed in brain lysates of G2019S transgenic mice. Our results suggest that cellular senescence is promoted via the p53-p21 pathway due to the G2019S LRRK2 mutation. Eventually, decreased protein degradation by G2019S-mediated senescence could accelerate αSyn aggregate formation.     

ACOT12-Dependent Alteration of Acetyl-CoA Drives Hepatocellular Carcinoma Metastasis by Epigenetic Induction of Epithelial-Mesenchymal Transition

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