Prolonged near-infrared fluorescence imaging of microRNAs and proteases in vivo by aggregation-enhanced emission from DNA-AuNC nanomachines.

Developing a comprehensive strategy for imaging various biomarkers (i.e., microRNAs and proteases) in vivo is an exceptionally formidable task. Herein, we have designed a deoxyribonucleic acid-gold nanocluster (DNA-AuNC) nanomachine for detecting tumor-related TK1 mRNA and cathepsin B in living cells and in vivo. The DNA-AuNC nanomachine is constructed using AuNCs and DNA modules that incorporate a three component DNA hybrid (TD) and a single-stranded fuel DNA (FD). Upon being internalized into tumor cells, the TK1 mRNA initiates the DNA-AuNC nanomachine through DNA strand displacement cascades, leading to the amplified self-assembly and the aggregation-enhanced emission of AuNCs for in situ imaging. Furthermore, with the aid of a protease nanomediator consisting of a mediator DNA/peptide complex and AuNCs (DpAuNCs), the DNA-AuNC nanomachine can be triggered by the protease-activated disassembly of the DNA/peptide complex on the nanomediator, resulting in the aggregation of AuNCs for in vivo protease amplified detection. It is worth noting that our study demonstrates the impressive tumor permeability and accumulation capabilities of the DNA-AuNC nanomachines via in situ amplified self-assembly, thereby facilitating prolonged imaging of TK1 mRNA and cathepsin B both in vitro and in vivo. This strategy presents a versatile and biomarker-specific paradigm for disease diagnosis.

Cell-Derived N/P/S-Codoped Fluorescent Carbon Nanodots with Intrinsic Targeting Ability for Tumor-Specific Phototheranostics.

Combining targeting ability, imaging function, and photothermal/photodynamic therapy into a single agent is highly desired for cancer theranostics. Herein, we developed a one-for-all nanoplatform with N/P/S-codoped fluorescent carbon nanodots (CNDs) for tumor-specific phototheranostics. The CNDs were prepared via a one-pot hydrothermal process using cancer cells as sources of carbon, nitrogen, phosphorus, and sulfur. The obtained N/P/S-codoped CNDs exhibit wide light absorption in the range of 200-900 nm and excitation-dependent emission with high photostability. Importantly, the cancer cell-derived N/P/S-codoped CNDs have outstanding biocompatibility and naturally intrinsic targeted ability for cancer cells as well as dual photothermal/photodynamic effects under 795 nm laser irradiation. Moreover, the photothermal conversion efficiency and singlet oxygen (1O2) generation efficiency were calculated to be 52 and 34%, respectively. These exceptional properties enable CNDs to act as fine theranostic agents for targeted imaging and photothermal-photodynamic synergistic therapy within the NIR therapeutic window. The CNDs prepared in this work are promising for construction as a universal tumor phototheranostic platform.

[Effect of Recombinant Human Thrombopoietin (rhTPO) on Long-term Hematopoietic Recovery in Mice with Acute Radiation Sickness and Relative Mechanism].

OBJECTIVE: To investigate the effect and relative mechanism of Recombinant Human Thrombopoietin (rhTPO) on long-term hematopoietic recovery in mice with acute radiation sickness. METHODS: Mice were intramuscularly injected with rhTPO (100 µg/kg) 2 hours after total body irradiation with 60Co γ-rays (6.5 Gy). Moreover, six months after irradiation, peripheral blood, hematopoietic stem cells (HSC) ratio, competitive transplantation survival rate and chimerization rate, senescence rate of c-kit+ HSC, and p16 and p38 mRNA expression of c-kit+ HSC were detected. RESULTS: Six months after 6.5 Gy γ-ray irradiation, there were no differences in peripheral blood white blood cells, red blood cells, platelets, neutrophils and bone marrow nucleated cells in normal group, irradiated group and rhTPO group (P>0.05). The proportion of hematopoietic stem cells and multipotent progenitor cells in mice of irradiated group was significantly decreased after irradiation (P<0.05), but there was no significant changes in rhTPO group (P>0.05). The counts of CFU-MK and BFU-E in irradiated group were significantly lower than that in normal group, and rhTPO group was higher than that of the irradiated group(P<0.05). The 70 day survival rate of recipient mice in normal group and rhTPO group was 100%, and all mice died in irradiation group. The senescence positive rates of c-kit+ HSC in normal group, irradiation group and rhTPO group were 6.11%, 9.54% and 6.01%, respectively (P<0.01). Compared with the normal group, the p16 and p38 mRNA expression of c-kit+ HSC in the irradiated mice were significantly increased (P<0.01), and it was markedly decreased after rhTPO administration (P<0.01). CONCLUSION: The hematopoietic function of mice is still decreased 6 months after 6.5 Gy γ-ray irradiation, suggesting that there may be long-term damage. High-dose administration of rhTPO in the treatment of acute radiation sickness can reduce the senescence of HSC through p38-p16 pathway and improve the long-term damage of hematopoietic function in mice with acute radiation sickness.

rhTPO Ameliorates Radiation-Induced Long-Term Hematopoietic Stem Cell Injury in Mice.

Exposure to medium and high doses of ionizing radiation (IR) can induce long-term bone marrow (BM) suppression. We previously showed that recombinant human thrombopoietin (rhTPO) significantly promotes recovery from hematopoietic-acute radiation syndrome, but its effect on long-term BM suppression remains unknown. C57BL/6 mice were exposed to 6.5 Gy γ-rays of total body irradiation (TBI) at a dose-rate of 63.01 cGy per minute, and the mice were treated with rhTPO (100 µg; intramuscular injection) or vehicle at 2 h after TBI. All mice were killed one or two months after TBI for analysis of peripheral blood cell counts, long-term hematopoietic stem cell (HSC) frequency, and BM-derived clonogenic activity. The HSC self-renewal capacity was analyzed by BM transplantation. The levels of reactive oxygen species (ROS) production and ratios of γH2AX+ and p16, p53, and p21 mRNA in HSCs were measured by flow cytometry and real-time polymerase chain reaction, respectively. Treatment with rhTPO reduced long-term myelosuppression by improving long-term hematopoietic reconstitution (p < 0.05) after transplantation and resting state maintenance of HSCs (p < 0.05). Moreover, rhTPO treatment was associated with a sustained reduction in long-term ROS production, reduction of long-term DNA damage, diminished p53/p21 mRNA expression, and prevention of senescence after TBI. This study suggests rhTPO is an effective agent for treating IR-induced long-term BM injury because it regulates hematopoietic remodeling and HSC cycle disorder through the ROS/p53/p21/p16 pathway long term after IR.

Synthesis, Optical Properties, and Fluorescence Cell Imaging of Novel Mixed Fluorinated Subphthalocyanines.

Subphthalocyanines (SubPcs) are a kind of tripyrrolic macrocycle with a boron atom at their core. Incorporating different units onto the SubPc periphery can endow them with various unique properties. Herein, a series of novel fluorinated low-symmetry SubPc derivatives containing chlorine groups (F8-Cl4-SubPc, F4-Cl8-SubPc) and methoxy groups (F8-(OCH3)2-SubPc) were synthesized and characterized by spectral methods (MS, FT-IR, 1H, 13C, 11B, and 19F NMR spectroscopy), and the effect of the peripheral substituents on their electronic structure of low-symmetry macrocycle was investigated by cyclic voltammetry, theoretical calculation, electronic absorption, and emission spectroscopy. In contrast to perfluorinated SubPcs, these low-symmetry SubPcs revealed non-degenerate LUMO and LUMO + 1 orbitals, especially F8-(OCH3)2-SubPc, which was consistent with the split Q-band absorptions. The cyclic voltammetry revealed that these SubPcs exhibited two or three reduction waves and one oxidation wave, which is consistent with the reported SubPcs. Finally, an intracellular fluorescence imaging study of these compounds revealed that these compounds could enter cancer cells and be entrapped in the lysosomes, which provides a possibility of future applications in lysosome fluorescence imaging and targeting.

[Therapeutic Effect of Single Intramuscular Administration of Recombinant Human Thrombopoietin on Rhesus Monkeys with Acute radiation Sickness].

OBJECTIVE: To confirm the therapeutic effect of recombinant human thrombopoietin (rhTPO) on rhesus monkeys irradiated with 5.0 Gy 60Co γ-ray, and provide experimental basis for clinical treatment of similar patients. METHODS: Fourteen adult rhesus monkeys were irradiated with 60Co γ-ray on both sides at the dose of 5.0 Gy (dose rate 69.2 cGy/min) to establish the acute radiation sickness model. The monkeys were divided into irradiation group (n=5), rhTPO 5 µg/kg group (n=4) and rhTPO 10 µg/kg group (n=5). Two hours after irradiation, the three groups of monkeys were injected with saline 0.1 ml/kg, rhTPO 5 µg/kg（0.1 ml/kg） and rhTPO 10 µg/kg(0.2 ml/kg), respectively. The general signs, survival, peripheral hemogram and serum biochemistry of rhesus monkeys were observed before and after irradiation, and the differences between rhTPO group and irradiation control group were compared. RESULTS: After total body irradiation with 5.0 Gy60Co γ-ray, rhesus monkeys successively showed fever, hemorrhage, sharp decrease of whole blood cell counts in peripheral blood and disorder of serum biochemical indexes. Compared with the irradiated control group, a single intramuscular injection of rhTPO 5 µg/kg or 10 µg/kg 2 hours after irradiation could improve the symptoms of fever and bleeding, increase the nadir of peripheral red blood cells and platelets counts, shorten the duration of hemocytopenia, and advance the time for blood cells to return to the pre-irradiation level. The serum biochemical results showed that rhTPO could improve the abnormality of serum biochemical indexes in rhesus monkeys induced by 5.0 Gy total body irradiation to some extent. Compared with the two administration groups, the therapeutic effect of rhTPO 10 µg/ kg was better. CONCLUSION: A single injection of rhTPO 5 µg/ kg or 10 µg/ kg 2 hours after irradiation can alleviate the injury of multilineage hematopoiesis and promote the recovery in monkeys irradiated by 5.0 Gy γ-ray. It also improves animal signs and has obvious therapeutic effect on acute radiation sickness.

Calcium supplementation increases circulating cholesterol by reducing its catabolism via GPER and TRPC1-dependent pathway in estrogen deficient women.

BACKGROUND: Limited studies have addressed the effects of calcium supplementation (CaS) on serum total cholesterol (TC) in postmenopausal women and the results are inconclusive. Moreover, the potential mechanisms through which CaS regulates cholesterol metabolism in the absence of estrogen are still sealed for the limitation of human being study. METHODS: Cross-sectional survey, animal and in vitro experiments were conducted to investigate the effect of CaS on endogenous cholesterol metabolism in estrogen deficiency and identify its potential mechanisms. Ovariectomized rats were used to mimic estrogen deficiency. In vitro, HepG2 cell line was exposed to estradiol and/or calcium treatment. RESULTS: We demonstrated that CaS significantly increased serum TC and the risk of hypercholesterolemia and myocardial infarction in postmenopausal women. Increased serum TC in estrogen deficiency was caused mainly by decreased cholesterol catabolism rather than increased synthesis. This was mediated by reduced 7α-hydroxylase resulting from increased liver intracellular Ca(2+) concentrations, reduced intracellular basal cAMP and subsequent up-regulation of SREBP-1c and SHP expression. Estrogen had a protective role in preventing CaS-induced TC increase by activating the G-protein coupled estrogen receptor, which mediated the estrogen effect through the transient receptor potential canonical 1 cation channel. CONCLUSIONS: CaS increases endogenous serum TC via decreasing hepatic cholesterol catabolism in estrogen deficiency. G-protein coupled estrogen receptor is shown to be a key target in mediating CaS-induced TC increase. CaS should be monitored for the prevention of serum TC increase during menopause.

Beneficial effects of mangiferin on hyperlipidemia in high-fat-fed hamsters.

SCOPE: Mangiferin, a natural polyphenol, has been shown to have hypolipidemic effect in rat and mouse. However, the mechanism of action is not well understood. This study was conducted to determine the effect and mechanism of action of mangiferin on hyperlipidemia induced in hamsters by a high-fat diet. METHODS AND RESULTS: Forty male hamsters were randomly assigned to normal control, high-fat control, and high fat with mangiferin (50 and 150 mg/kg BW) groups. Mangiferin treatment significantly decreased final body weight, liver weight and visceral fat-pad weight, serum triglyceride (TG) and total free fatty acid (FFA) concentrations, hepatic TG levels and hepatic and muscle total FFA contents. Mangiferin upregulated mRNA expression of peroxisome proliferator-activated receptor-α (PPAR-α), fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT-1), but downregulated mRNA expression of sterol regulatory element-binding protein 1c (SREBP-1c), acetyl CoA carboxylase (ACC), acyl-CoA:diacylglycerol acyltransferase 2 (DGAT-2) and microsomal triglyceride transfer protein (MTP) in liver. Mangiferin also stimulated mRNA expression of PPAR-α, CD36, CPT-1 and lipoprotein lipase (LPL) in muscle. CONCLUSIONS: The results suggest that mangiferin may ameliorate hypertriglyceridemia partly by modulating the expression levels of genes involved in lipid oxidation and lipogenesis.