RESUMO
Premature ovarian failure (POF) features an upward incidence nowadays, and the human umbilical cord mesenchymal stem cells (hUC-MSCs)-derived exosomes (MSC-Exos) have shown applied values in the recovery of ovarian function. Here, a novel exosome-encapsulated microcarrier prepared by microfluidic technology for ovarian repair after chemotherapy damage is presented. The exosomes derived from lipopolysaccharide (LPS)-preconditioned hUC-MSCs are encapsulated with hyaluronic acid methacryloyl (HAMA) via microfluidic electrospray, which is named HAMA/MSC-Exos. Attributing to the biocompatibility and semipermeable property of HAMA, the encapsulated exosomes show great viability and controllable release behavior from HAMA. It is demonstrated that in situ transplantation of HAMA/MSC-Exos can rescue ovarian functions of cyclophosphamide-induced ovarian failure in mice by increasing ovarian volume, improving the number of antral follicles and restoring fertility. It is believed that the transplantation of HAMA/MSC-Exos will provide a new concept for the treatment of POF in clinical practice.
Assuntos
Exossomos , Células-Tronco Mesenquimais , Humanos , Animais , Camundongos , Ácido Hialurônico/farmacologia , Lipopolissacarídeos/farmacologia , MicrofluídicaRESUMO
We have demonstrated an environmentally friendly in situ assembly method for the preparation of novel three-dimensional TiO2/graphene oxide (TiO2/GO) nanostructures with favorable flower-shaped architectures. Very little information on such a morphology of TiO2/GO nanostructures is available in the literature. The as-synthesized sample was characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption measurements and Raman spectroscopy. Also the TiO2/GO composites exhibited enhanced photocatalytic properties.
Assuntos
Grafite/química , Nanopartículas/química , Óxidos/química , Titânio/química , Catálise , Química Verde , Nanopartículas/ultraestruturaRESUMO
China's forests play a vital role in the global carbon cycle through the absorption of atmospheric CO2 to mitigate climate change caused by the increase of anthropogenic CO2. It is essential to evaluate the carbon sink potential (CSP) of China's forest ecosystem. Combining NDVI, field-investigated, and vegetation and soil carbon density data modeled by process-based models, we developed the state-of-the-art learning ensembles model of process-based models (the multi-model random forest ensemble (MMRFE) model) to evaluate the carbon stocks of China's forest ecosystem in historical (1982-2021) and future (2022-2081, without NDVI-driven data) periods. Meanwhile, we proposed a new carbon sink index (CSindex) to scientifically and accurately evaluate carbon sink status and identify carbon sink intensity zones, reducing the probability of random misjudgments as a carbon sink. The new MMRFE models showed good simulation results in simulating forest vegetation and soil carbon density in China (significant positive correlation with the observed values, r = 0.94, P < 0.001). The modeled results show that a cumulative increase of 1.33 Pg C in historical carbon stocks of forest ecosystem is equivalent to 48.62 Bt CO2, which is approximately 52.03% of the cumulative increased CO2 emissions in China from 1959 to 2018. In the next 60 years, China's forest ecosystem will absorb annually 1.69 (RCP45 scenario) to 1.85 (RCP85 scenario) Bt CO2. Compared with the carbon stock in the historical period, the cumulative absorption of CO2 by China's forest ecosystem in 2032-2036, 2062-2066, and 2077-2081 are approximately 11.25-39.68, 110.66-121.49 and 101.31-111.11 Bt CO2, respectively. In historical and future periods, the medium and strong carbon sink intensity regions identified by the historical CSindex covered 65% of the total forest area, cumulative absorbing approximately 31.60 and 65.83-72.22 Bt CO2, respectively. In the future, China's forest ecosystem has a large CSP with a non-continuous increasing trend. However, the CSP should not be underestimated. Notably, the medium carbon sink intensity region should be the priority for natural carbon sequestration action. This study not only provides an important methodological basis for accurately estimating the future CSP of forest ecosystem but also provides important decision support for future forest ecosystem carbon sequestration action.
RESUMO
With aging, abnormalities during oocyte meiosis become more prevalent. However, the mechanisms of aging-related oocyte aneuploidy are not fully understood. Here we performed Hi-C and SMART-seq of oocytes from young and old mice and reveal decreases in chromosome condensation and disrupted meiosis-associated gene expression in metaphase I oocytes from aged mice. Further transcriptomic analysis showed that meiotic maturation in young oocytes was correlated with robust increases in mevalonate (MVA) pathway gene expression in oocyte-surrounding granulosa cells (GCs), which was largely downregulated in aged GCs. Inhibition of MVA metabolism in GCs by statins resulted in marked meiotic defects and aneuploidy in young cumulus-oocyte complexes. Correspondingly, supplementation with the MVA isoprenoid geranylgeraniol ameliorated oocyte meiotic defects and aneuploidy in aged mice. Mechanically, we showed that geranylgeraniol activated LHR/EGF signaling in aged GCs and enhanced the meiosis-associated gene expression in oocytes. Collectively, we demonstrate that the MVA pathway in GCs is a critical regulator of meiotic maturation and euploidy in oocytes, and age-associated MVA pathway abnormalities contribute to oocyte meiotic defects and aneuploidy.
Assuntos
Ácido Mevalônico , Oócitos , Feminino , Camundongos , Animais , Ácido Mevalônico/metabolismo , Oócitos/metabolismo , Células da Granulosa/metabolismo , Meiose/genética , AneuploidiaRESUMO
We have demonstrated an environment-friendly biomimetic synthesis method for the preparation of TiO(2) nanomaterials with different crystal phases and morphologies. This is the first time that it has been found that the crystal phase of TiO(2) can be controlled just by using different biotemplates, and cannot be changed by calcination up to 750 °C. In our experiment, anatase TiO(2) was obtained by using yeast and albumen templates, while rutile TiO(2) was formed by using dandelion pollen as the template.
Assuntos
Materiais Biomiméticos/síntese química , Biopolímeros/química , Química Verde/métodos , Impressão Molecular/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Titânio/química , Catálise , Cristalização/métodos , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Fotoquímica/métodos , Propriedades de SuperfícieRESUMO
Periodontitis is a chronic infectious disease that alters the cellular microenvironment and promotes bone absorption. Bone morphogenetic protein 9 (BMP9) serves an important role in proliferation and differentiation, and tumor necrosis factoralpha (TNFα) is an important contributor to bone resorption. The present study aimed to investigate the effect of osteogenic differentiation in the presence of BMP9 and TNFα in rat follicle stem cells (rDFCs). rDFCs were transfected with adenoviruses expressing BMP9 (AdBMP9) and the expression levels of important proteins [BMP9, ßcatenin, glycogen synthase kinase 3ß (GSK3ß), phosphorylatedGSK3ß, calcium/calmodulin dependent protein kinase II and nemo like kinase] were determined using western blotting. The effect of osteogenesis was analyzed using reverse transcriptionquantitative PCR, in addition to alkaline phosphatase, Alizarin Red S, and hematoxylin and eosin staining methods. The results of the present study revealed that TNFα activated the canonical Wnt signaling pathway and suppressed osteogenesis. High concentrations of Dickkopf 1 (DKK1) reduced the osteogenic differentiation of AdBMP9transduced rDFCs, whereas low concentrations of DKK1 promoted BMP9induced bone formation, which was discovered to partially act via the canonical and noncanonical Wnt signaling pathways. In conclusion, the findings of the present study suggested that the enhanced promoting effect of BMP9 alongside the treatment with low concentrations of DKK1 may be useful for treating periodontitis bone absorption.
Assuntos
Dependovirus/genética , Fator 2 de Diferenciação de Crescimento/genética , Osteogênese , Células-Tronco/citologia , Fator de Necrose Tumoral alfa/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Masculino , Fosforilação , Ratos , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Transdução Genética , Via de Sinalização Wnt/efeitos dos fármacosRESUMO
Homogeneously distributed self-assembling hybrid graphene-based aerogels with 3D interconnected pores, employing three types of carbohydrates (glucose, ß-cyclodextrin, and chitosan), have been fabricated by a simple hydrothermal route. Using three types of carbohydrates as morphology oriented agents and reductants can effectively tailor the microstructures, physical properties, and electrochemical performances of the products. The effects of different carbohydrates on graphene oxide reduction to form graphene-based aerogels with different microcosmic morphologies and physical properties were also systemically discussed. The electrochemical behaviors of all graphene-based aerogel samples showed remarkably strong and stable performances, which indicated that all the 3D interpenetrating microstructure graphene-based aerogel samples with well-developed porous nanostructures and interconnected conductive networks could provide fast ionic channels for electrochemical energy storage. These results demonstrate that this strategy would offer an easy and effective way to fabricate graphene-based materials.