Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 20
Filter
Add more filters










Publication year range
1.
J Genet Genomics ; 50(9): 661-675, 2023 09.
Article in English | MEDLINE | ID: mdl-37230320

ABSTRACT

Prior to the generation of hematopoietic stem cells (HSCs) from the hemogenic endothelial cells (HECs) mainly in the dorsal aorta in midgestational mouse embryos, multiple hematopoietic progenitors including erythro-myeloid progenitors and lymphoid progenitors are generated from yolk sac HECs. These HSC-independent hematopoietic progenitors have recently been identified as major contributors to functional blood cell production until birth. However, little is known about yolk sac HECs. Here, combining integrative analyses of multiple single-cell RNA-sequencing datasets and functional assays, we reveal that Neurl3-EGFP, in addition to marking the continuum throughout the ontogeny of HSCs from HECs, can also serve as a single enrichment marker for yolk sac HECs. Moreover, while yolk sac HECs have much weaker arterial characteristics than either arterial endothelial cells in the yolk sac or HECs within the embryo proper, the lymphoid potential of yolk sac HECs is largely confined to the arterial-biased subpopulation featured by the Unc5b expression. Interestingly, the B lymphoid potential of hematopoietic progenitors, but not for myeloid potentials, is exclusively detected in Neurl3-negative subpopulations in midgestational embryos. Taken together, these findings enhance our understanding of blood birth from yolk sac HECs and provide theoretical basis and candidate reporters for monitoring step-wise hematopoietic differentiation.


Subject(s)
Hemangioblasts , Hematopoiesis , Animals , Mice , Cell Differentiation/genetics , Embryo, Mammalian/metabolism , Hemangioblasts/metabolism , Hematopoiesis/genetics , Hematopoietic Stem Cells , Ubiquitin-Protein Ligases/metabolism
2.
Adv Sci (Weinh) ; 10(6): e2203813, 2023 02.
Article in English | MEDLINE | ID: mdl-36638254

ABSTRACT

In the aorta of mid-gestational mouse embryos, a specialized endothelial subpopulation termed hemogenic endothelial cells (HECs) develops into hematopoietic stem and progenitor cells (HSPCs), through a conserved process of endothelial-to-hematopoietic transition (EHT). EHT is tightly controlled by multiple intrinsic and extrinsic mechanisms. Nevertheless, the molecular regulators restraining this process remain poorly understood. Here, it is uncovered that, one of the previously identified HEC signature genes, Nupr1, negatively regulates the EHT process. Nupr1 deletion in endothelial cells results in increased HSPC generation in the aorta-gonad-mesonephros region. Furthermore, single-cell transcriptomics combined with serial functional assays reveals that loss of Nupr1 promotes the EHT process by promoting the specification of hematopoiesis-primed functional HECs and strengthening their subsequent hematopoietic differentiation potential toward HSPCs. This study further finds that the proinflammatory cytokine, tumor necrosis factor α (TNF-α), is significantly upregulated in Nupr1-deficient HECs, and the use of a specific TNF-α neutralizing antibody partially reduces excessive HSPC generation in the explant cultures from Nupr1-deficient embryos. This study identifies a novel negative regulator of EHT and the findings indicate that Nupr1 is a new potential target for future hematopoietic stem cell regeneration research.


Subject(s)
Endothelial Cells , Mesonephros , Animals , Mice , Aorta , Gonads , Tumor Necrosis Factor-alpha
3.
J Colloid Interface Sci ; 630(Pt B): 855-865, 2023 Jan 15.
Article in English | MEDLINE | ID: mdl-36356451

ABSTRACT

Due to the high incidence of kidney disease, there is an urgent need to develop wearable artificial kidneys. This need is further exacerbated by the coronavirus disease 2019 pandemic. However, the dialysate regeneration system of the wearable artificial kidney has a low adsorption capacity for urea, which severely limits its application. Therefore, nanomaterials that can effectively remove uremic toxins, especially urea, to regenerate dialysate are required and should be further investigated and developed. Herein, flower-like molybdenum disulphide (MoS2) nanosheets decorated with highly dispersed cerium oxide (CeO2) were prepared (MoS2/CeO2), and their adsorption performances for urea, creatinine, and uric acid were studied in detail. Due to the open interlayer structures and the combination of MoS2 and CeO2, which can provide abundant adsorption active sites, the MoS2/CeO2 nanomaterials present excellent uremic toxin adsorption activities. Further, uremic toxin adsorption capacities were also assessed using a self-made fixed bed device under dynamic conditions, with the aim of developing MoS2/CeO2 for the practical adsorption of uremic toxins. In addition, the biocompatibility of MoS2/CeO2 was systematically analyzed using hemocompatibility and cytotoxicity assays. Our data suggest that MoS2/CeO2 can be safely used for applications requiring close contact with blood. Our findings confirm that novel 2-dimensional nanomaterial adsorbents have significant potential for dialysis fluid regeneration.


Subject(s)
COVID-19 , Cerium , Humans , Molybdenum/chemistry , Uremic Toxins , Adsorption , Dialysis Solutions/chemistry , Urea , Cerium/pharmacology
4.
Bioact Mater ; 21: 381-393, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36185743

ABSTRACT

Acute kidney injury (AKI) can lead to loss of kidney function and a substantial increase in mortality. The burst of reactive oxygen species (ROS) plays a key role in the pathological progression of AKI. Mitochondrial-targeted antioxidant therapy is very promising because mitochondria are the main source of ROS in AKI. Antioxidant nanodrugs with actively targeted mitochondria have achieved encouraging success in many oxidative stress-induced diseases. However, most strategies to actively target mitochondria make the size of nanodrugs too large to pass through the glomerular system to reach the renal tubules, the main damage site of AKI. Here, an ultra-small Tungsten-based nanodots (TWNDs) with strong ROS scavenging can be very effective for treatment of AKI. TWNDs can reach the tubular site after crossing the glomerular barrier, and enter the mitochondria of the renal tubule without resorting to complex active targeting strategies. To our knowledge, this is the first time that ultra-small negatively charged nanodots can be used to passively target mitochondrial therapy for AKI. Through in-depth study of the therapeutic mechanism, such passive mitochondria-targeted TWNDs are highly effective in protecting mitochondria by reducing mitochondrial ROS and increasing mitophagy. In addition, TWNDs can also reduce the infiltration of inflammatory cells. This work provides a new way to passively target mitochondria for AKI, and give inspiration for the treatment of many major diseases closely related to mitochondria, such as myocardial infarction and cerebral infarction.

5.
Cell Stem Cell ; 29(11): 1531-1546.e7, 2022 Nov 03.
Article in English | MEDLINE | ID: mdl-36265493

ABSTRACT

The communication between glioblastoma stem cells (GSCs) and the surrounding microenvironment is a prominent feature accounting for the aggressive biology of glioblastoma multiforme (GBM). However, the mechanisms by which GSCs proactively drive interactions with microenvironment is not well understood. In this study, we interrogated metabolites that are preferentially secreted from GSCs and found that GSCs produce and secrete histamine to shape a pro-angiogenic tumor microenvironment. This histamine-producing ability is attributed to H3K4me3 modification-activated histidine decarboxylase (HDC) transcription via MYC. Notably, HDC is highly expressed in GBM, which is associated with poor survival of these patients. GSC-secreted histamine activates endothelial cells by triggering a histamine H1 receptor (H1R)-Ca2+-NF-κB axis, thereby promoting angiogenesis and GBM progression. Importantly, pharmacological blockage of H1R using antihistamines impedes the growth of GBM xenografts in mice. Our findings establish that GSC-specific metabolite secretion remodels the tumor microenvironment and highlight histamine targeting as a potential strategy for GBM therapy.


Subject(s)
Brain Neoplasms , Glioblastoma , Humans , Mice , Animals , Glioblastoma/pathology , Histamine/metabolism , Tumor Microenvironment , Brain Neoplasms/pathology , Endothelial Cells/metabolism , Neoplastic Stem Cells/pathology , Cell Line, Tumor
6.
Br J Cancer ; 127(4): 612-623, 2022 09.
Article in English | MEDLINE | ID: mdl-35501390

ABSTRACT

BACKGROUND: The mechanism of recurrence and metastasis of hepatocellular carcinoma (HCC) is complex and challenging. Methyl-CpG binding domain protein 3 (MBD3) is a key epigenetic regulator involved in the progression and metastasis of several cancers, but its role in HCC remains unknown. METHODS: MBD3 expression in HCC was detected by immunohistochemistry and its association with clinicopathological features and patient's survival was analysed. The effects of MBD3 on hepatoma cells growth and metastasis were investigated, and the mechanism was explored. RESULTS: MBD3 is significantly highly expressed in HCC, associated with the advanced tumour stage and poor prognosis in HCC patients. MBD3 promotes the growth, angiogenesis and metastasis of HCC cells by inhibiting the tumour suppressor tissue factor pathway inhibitor 2 (TFPI2). Mechanistically, MBD3 can inhibit the TFPI2 transcription via the Nucleosome Remodeling and Deacetylase (NuRD) complex-mediated deacetylation, thus reactivating the activity of matrix metalloproteinases (MMPs) and PI3K/AKT signaling pathway, leading to the progression and metastasis of HCC CONCLUSIONS: Our results unravel the novel regulatory function of MBD3 in the progression and metastasis of HCC and identify MBD3 as an independent unfavourable prognostic factor for HCC patients, suggesting its potential as a promising therapeutic target as well.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Carcinoma, Hepatocellular/metabolism , Cell Line, Tumor , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Neoplastic , Glycoproteins , Humans , Liver Neoplasms/metabolism , Mi-2 Nucleosome Remodeling and Deacetylase Complex/metabolism , Neoplasm Metastasis , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Transcription Factors/metabolism
7.
ACS Appl Bio Mater ; 5(3): 1297-1304, 2022 03 21.
Article in English | MEDLINE | ID: mdl-35262321

ABSTRACT

A photoelectrochemical (PEC) electrode for glucose detection was built based on polyaniline (PANI) modified titanium dioxide heterojunction (FH-TiO2) structures. Ultrathin titanium dioxide (TiO2) nanosheets are assembled onto rutile nanorods (TiO2 NRs). Experiments show that the main exposed faces of these nanosheets are (101) or (111) crystal planes. Proven by theoretical calculation, the bottom of the conduction band (CB) of (111) is 0.15 eV lower than the bottom of the conduction band of (101). Therefore, when the material is excited by light, photogenerated electrons are able to transfer from the conduction band of (101) to the conduction band of (111). PANI was introduced as a medium to effectively conduct photogenerated charges between glucose oxidase and titanium dioxide. A photoelectric detection electrode for glucose was fabricated by loading glucose oxidase onto PANI@FH-TiO2. This electrode showed excellent performance in 0.2-1.0 mM linear range with a sensitivity 15.63 µA mM-1 cm-2 and 1.0-15.0 mM linear range with a sensitivity of 1.42 µA mM-1 cm-2.


Subject(s)
Biosensing Techniques , Glucose Oxidase , Aniline Compounds , Glucose , Titanium
9.
Nat Commun ; 13(1): 931, 2022 02 17.
Article in English | MEDLINE | ID: mdl-35177641

ABSTRACT

Koolen-de Vries syndrome (KdVS) is a rare disorder caused by haploinsufficiency of KAT8 regulatory NSL complex subunit 1 (KANSL1), which is characterized by intellectual disability, heart failure, hypotonia, and congenital malformations. To date, no effective treatment has been found for KdVS, largely due to its unknown pathogenesis. Using siRNA screening, we identified KANSL1 as an essential gene for autophagy. Mechanistic study shows that KANSL1 modulates autophagosome-lysosome fusion for cargo degradation via transcriptional regulation of autophagosomal gene, STX17. Kansl1+/- mice exhibit impairment in the autophagic clearance of damaged mitochondria and accumulation of reactive oxygen species, thereby resulting in defective neuronal and cardiac functions. Moreover, we discovered that the FDA-approved drug 13-cis retinoic acid can reverse these mitophagic defects and neurobehavioral abnormalities in Kansl1+/- mice by promoting autophagosome-lysosome fusion. Hence, these findings demonstrate a critical role for KANSL1 in autophagy and indicate a potentially viable therapeutic strategy for KdVS.


Subject(s)
Abnormalities, Multiple/genetics , Intellectual Disability/genetics , Mitophagy/genetics , Nuclear Proteins/genetics , Abnormalities, Multiple/drug therapy , Abnormalities, Multiple/immunology , Abnormalities, Multiple/pathology , Animals , Autophagosomes/drug effects , Autophagosomes/metabolism , Autophagosomes/pathology , Cerebral Cortex/cytology , Cerebral Cortex/pathology , Chromosome Deletion , Chromosomes, Human, Pair 17/genetics , Chromosomes, Human, Pair 17/immunology , Disease Models, Animal , Female , Haploinsufficiency/immunology , HeLa Cells , Humans , Intellectual Disability/drug therapy , Intellectual Disability/immunology , Intellectual Disability/pathology , Isotretinoin/pharmacology , Isotretinoin/therapeutic use , Lysosomes/drug effects , Lysosomes/metabolism , Lysosomes/pathology , Mice , Mice, Transgenic , Mitophagy/drug effects , Mitophagy/immunology , Neurons , Nuclear Proteins/metabolism , Primary Cell Culture
10.
Nat Commun ; 12(1): 7003, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34853298

ABSTRACT

Cancer cells acquire genetic heterogeneity to escape from immune surveillance during tumor evolution, but a systematic approach to distinguish driver from passenger mutations is lacking. Here we investigate the impact of different immune pressure on tumor clonal dynamics and immune evasion mechanism, by combining massive parallel sequencing of immune edited tumors and CRISPR library screens in syngeneic mouse tumor model and co-culture system. We find that the core microRNA (miRNA) biogenesis and targeting machinery maintains the sensitivity of cancer cells to PD-1-independent T cell-mediated cytotoxicity. Genetic inactivation of the machinery or re-introduction of ANKRD52 frequent patient mutations dampens the JAK-STAT-interferon-γ signaling and antigen presentation in cancer cells, largely by abolishing miR-155-targeted silencing of suppressor of cytokine signaling 1 (SOCS1). Expression of each miRNA machinery component strongly correlates with intratumoral T cell infiltration in nearly all human cancer types. Our data indicate that the evolutionarily conserved miRNA pathway can be exploited by cancer cells to escape from T cell-mediated elimination and immunotherapy.


Subject(s)
Immune Evasion , MicroRNAs/metabolism , Neoplasms , Animals , Cell Line, Tumor , Chemokines/metabolism , Genetic Heterogeneity , Humans , Immunotherapy , Interferon-gamma , Mice , Mice, Inbred C57BL , Mice, Nude , Neoplasms/genetics , Phosphoprotein Phosphatases , Programmed Cell Death 1 Receptor , Signal Transduction , Suppressor of Cytokine Signaling 1 Protein , T-Lymphocytes
11.
Int Rev Cell Mol Biol ; 362: 171-207, 2021.
Article in English | MEDLINE | ID: mdl-34253295

ABSTRACT

It has been demonstrated for more than 40 years that intracellular calcium (Ca2+) controls a variety of cellular functions, including mitochondrial metabolism and cell proliferation. Cytosolic Ca2+ fluctuation during key stages of the cell cycle can lead to mitochondrial Ca2+ uptake and subsequent activation of mitochondrial oxidative phosphorylation and a range of signaling. However, the relationship between mitochondrial Ca2+ and cell cycle progression has long been neglected because the molecule responsible for Ca2+ uptake has been unknown. Recently, the identification of the mitochondrial Ca2+ uniporter (MCU) has led to key advances. With improved Ca2+ imaging and detection, effects of MCU-mediated mitochondrial Ca2+ have been observed at different stages of the cell cycle. Elevated Ca2+ signaling boosts ATP and ROS production, remodels cytosolic Ca2+ pathways and reprograms cell fate-determining networks. These findings suggest that manipulating mitochondrial Ca2+ signaling may serve as a potential strategy in the control of many crucial biological events, such as tumor development and cell division in hematopoietic stem cells (HSCs). In this review, we summarize the current understanding of the role of mitochondrial Ca2+ signaling during different stages of the cell cycle and highlight the potential physiological and pathological significance of mitochondrial Ca2+ signaling.


Subject(s)
Calcium/metabolism , Cell Cycle , Mitochondria/metabolism , Animals , Calcium Channels/metabolism , Calcium Signaling , Cytosol/metabolism , Humans
12.
J Colloid Interface Sci ; 567: 10-17, 2020 May 01.
Article in English | MEDLINE | ID: mdl-32036113

ABSTRACT

Recently, photocatalysts with a hollow mesoporous structure have drawn increasing interest owing to their extensive application in environmental protection. Herein, we prepared hollow mesoporous TiO2 nanospheres decorated with few layer 1T- and 2H- mixed phase MoS2 nanosheets via a template-based method and a hydrothermal reaction. The as-synthesized samples are of hollow mesoporous structure and high specific surface area, providing abundant mass transport and active sites for photocatalytic reaction. 1T-MoS2 in the mixed phase MoS2 mainly play the role as a bridge that transfers photoexcited electrons. Besides, the heterojunction between MoS2 and TiO2 can also efficiently restrain the recombination of photogenerated charge carriers in photocatalysts. As a consequence, under UV-vis light irradiation, the hollow porous TiO2/MoS2 presents a remarkable photocatalytic activity in rhodaming B degradation. Scavenger studies demonstrate that the primary active species in photocatalytic process are hydroxyl radicals. Moreover, a possible photocatalytic reaction mechanism has also been put forward.

13.
Nat Cell Biol ; 21(4): 476-486, 2019 04.
Article in English | MEDLINE | ID: mdl-30858581

ABSTRACT

The capacity of cells to alter bioenergetics in response to the demands of various biological processes is essential for normal physiology. The coordination of energy sensing and production with highly energy-demanding cellular processes, such as cell division, is poorly understood. Here, we show that a cell cycle-dependent mitochondrial Ca2+ transient connects energy sensing to mitochondrial activity for mitotic progression. The mitochondrial Ca2+ uniporter (MCU) mediates a rapid mitochondrial Ca2+ transient during mitosis. Inhibition of mitochondrial Ca2+ transients via MCU depletion causes spindle checkpoint-dependent mitotic delay. Cellular ATP levels drop during early mitosis, and the mitochondrial Ca2+ transients boost mitochondrial respiration to restore energy homeostasis. This is achieved through mitosis-specific MCU phosphorylation and activation by the mitochondrial translocation of energy sensor AMP-activated protein kinase (AMPK). Our results establish a critical role for AMPK- and MCU-dependent mitochondrial Ca2+ signalling in mitosis and reveal a mechanism of mitochondrial metabolic adaptation to acute cellular energy stress.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Calcium Channels/physiology , Calcium/metabolism , Mitochondria/metabolism , Mitosis , Adenosine Triphosphate/biosynthesis , Animals , Calcium Channels/genetics , Cell Line , Cells, Cultured , HeLa Cells , Humans , Mice, Inbred C57BL , Microtubules/metabolism , Mitochondria/enzymology
14.
Clin Cancer Res ; 25(4): 1302-1317, 2019 02 15.
Article in English | MEDLINE | ID: mdl-30429198

ABSTRACT

PURPOSE: The aberrantly upregulated Friend leukemia virus integration 1 (FLI1) is closely correlated with the malignant phenotype of small cell lung cancer (SCLC). It is interesting to note that the CRISPR gene knockout by Cas9 gRNAs that target the FLI1 coding region and the posttranscriptional knockdown by shRNAs that target the 3' region of FLI1 mRNA yielded distinct antimetastasis effects in SCLC cells. This study attempts to examine if FLI1 exonic circular RNAs (FECR) function as a new malignant driver that determines the metastatic phenotype in SCLC. EXPERIMENTAL DESIGN: The clinical relevance of FECRs was examined in 56 primary SCLC tissues and 50 non-small cell lung cancer (NSCLC) tissues. The prognostic value of FECRs was examined by measuring serum exosomal FECRs in a longitudinal cohort of patients with SCLC. The oncogenic activity of FECRs was investigated in both SCLC cell lines and animal xenograft studies. Finally, we explored the molecular mechanisms underlying these noncoding RNAs as a malignant driver. RESULTS: Therapeutic comparison of CRISPR Cas9 knockout and shRNA knockdown of FLI1 identified FECRs as a new noncanonical malignant driver in SCLC. Using RNA FISH and quantitative PCR, we found that FECR1 (exons 4-2-3) and FECR2 (exons 5-2-3-4) were aberrantly upregulated in SCLC tissues (P < 0.0001), and was positively associated with lymph node metastasis (P < 0.01). Notably, serum exosomal FECR1 was associated with poor survival (P = 0.038) and clinical response to chemotherapy. Silencing of FECRs significantly inhibited the migration in two highly aggressive SCLC cell lines and reduced tumor metastasis in vivo. Mechanistically, we uncovered that FECRs sequestered and subsequently inactivated tumor suppressor miR584-3p, leading to the activation of the Rho Associated Coiled-Coil Containing Protein Kinase 1 gene (ROCK1). CONCLUSIONS: This study identifies FLI1 exonic circular RNAs as a new oncogenic driver that promotes tumor metastasis through the miR584-ROCK1 pathway. Importantly, serum exosomal FECR1 may serve as a promising biomarker to track disease progression of SCLC.


Subject(s)
MicroRNAs/genetics , Proto-Oncogene Protein c-fli-1/genetics , RNA, Circular/genetics , Small Cell Lung Carcinoma/genetics , rho-Associated Kinases/genetics , A549 Cells , Animals , Apoptosis/genetics , CRISPR-Cas Systems/genetics , Carcinoma, Non-Small-Cell Lung/blood , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/pathology , Cell Cycle/genetics , Cell Movement/genetics , Cell Proliferation/genetics , Exons/genetics , Exosomes/genetics , Heterografts , Humans , Mice , Neoplasm Metastasis , Proto-Oncogene Protein c-fli-1/antagonists & inhibitors , RNA, Circular/isolation & purification , RNA, Small Interfering/genetics , Small Cell Lung Carcinoma/blood , Small Cell Lung Carcinoma/pathology
15.
Autophagy ; 14(10): 1818-1830, 2018.
Article in English | MEDLINE | ID: mdl-30103670

ABSTRACT

Aged and damaged mitochondria can be selectively degraded by specific autophagic elimination, termed mitophagy. Defects in mitophagy have been increasingly linked to several diseases including neurodegenerative diseases, metabolic diseases and other aging-related diseases. However, the molecular mechanisms of mitophagy are not fully understood. Here, we identify PRPF8 (pre-mRNA processing factor 8), a core component of the spliceosome, as an essential mediator in hypoxia-induced mitophagy from an RNAi screen based on a fluorescent mitophagy reporter, mt-Keima. Knockdown of PRPF8 significantly impairs mitophagosome formation and subsequent mitochondrial clearance through the aberrant mRNA splicing of ULK1, which mediates macroautophagy/autophagy initiation. Importantly, autosomal dominant retinitis pigmentosa (adRP)-associated PRPF8 mutant R2310K is defective in regulating mitophagy. Moreover, knockdown of other adRP-associated splicing factors, including PRPF6, PRPF31 and SNRNP200, also lead to ULK1 mRNA mis-splicing and mitophagy defects. Thus, these findings demonstrate that PRPF8 is essential for mitophagy and suggest that dysregulation of spliceosome-mediated mitophagy may contribute to pathogenesis of retinitis pigmentosa.


Subject(s)
Autophagy-Related Protein-1 Homolog/genetics , Genes, Dominant , Hypoxia/genetics , Mitophagy/genetics , RNA Splicing Factors/genetics , RNA Splicing/genetics , RNA-Binding Proteins/genetics , Retinitis Pigmentosa/genetics , Animals , Autophagy-Related Protein-1 Homolog/metabolism , Gene Expression Regulation , HeLa Cells , Humans , Mice , Mutation/genetics , Phagosomes/metabolism , Phagosomes/ultrastructure , RNA Interference , RNA Splicing Factors/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Spliceosomes/metabolism
16.
J Colloid Interface Sci ; 512: 47-54, 2018 Feb 15.
Article in English | MEDLINE | ID: mdl-29054006

ABSTRACT

Photocatalysts with a hierarchically porous structure have attracted considerable attention owing to their wide pore size distribution and high surface area, which enhance the efficiency of transporting species to active sites. In this study, hierarchically meso-macroporous TiO2 photocatalysts decorated with highly dispersed CdS nanoparticles were synthesized via hydrolysis, followed by a hydrothermal treatment. The textural mesopores and interconnected pore framework provided more accessible active sites and efficient mass transport for the photocatalytic process. The light collection efficiency was enhanced because of multiple scattering of incident light in the macropores. Moreover, the formation of a heterojunction between the CdS and TiO2 nanoparticles extended the photoresponse of TiO2 to the visible-light range and enhanced the charge separation efficiency. Therefore, the hierarchically meso-macroporous TiO2/CdS photocatalysts exhibited excellent photocatalytic activity for the degradation of rhodaming B under visible-light irradiation. Trapping experiments demonstrated that superoxide radicals (O2-) and hydroxyl radicals (OH) were the main active species in photocatalysis. A reasonable photocatalytic mechanism of TiO2/CdS heterojunction photocatalysts was also presented.

17.
Stem Cell Reports ; 9(3): 927-942, 2017 09 12.
Article in English | MEDLINE | ID: mdl-28826851

ABSTRACT

The roles of histone demethylases (HDMs) for the establishment and maintenance of pluripotency are incompletely characterized. Here, we show that JmjC-domain-containing protein 1c (JMJD1C), an H3K9 demethylase, is required for mouse embryonic stem cell (ESC) self-renewal. Depletion of Jmjd1c leads to the activation of ERK/MAPK signaling and epithelial-to-mesenchymal transition (EMT) to induce differentiation of ESCs. Inhibition of ERK/MAPK signaling rescues the differentiation phenotype caused by Jmjd1c depletion. Mechanistically, JMJD1C, with the help of pluripotency factor KLF4, maintains ESC identity at least in part by regulating the expression of the miR-200 family and miR-290/295 cluster to suppress the ERK/MAPK signaling and EMT. Additionally, we uncover that JMJD1C ensures efficient generation and maintenance of induced pluripotent stem cells, at least partially through controlling the expression of microRNAs. Collectively, we propose an integrated model of epigenetic and transcriptional control mediated by the H3K9 demethylase for ESC self-renewal and somatic cell reprogramming.


Subject(s)
Cell Self Renewal , Gene Expression Regulation , Jumonji Domain-Containing Histone Demethylases/metabolism , MicroRNAs/genetics , Mouse Embryonic Stem Cells/metabolism , Animals , Cell Differentiation , Epithelial-Mesenchymal Transition , Gene Knockdown Techniques , HEK293 Cells , Humans , Kruppel-Like Factor 4 , Kruppel-Like Transcription Factors/metabolism , MAP Kinase Signaling System , Mice , MicroRNAs/metabolism , Phenotype
18.
J Biol Chem ; 292(20): 8507-8519, 2017 05 19.
Article in English | MEDLINE | ID: mdl-28298436

ABSTRACT

The unique properties of embryonic stem cells (ESCs), including unlimited self-renewal and pluripotent differentiation potential, are sustained by integrated genetic and epigenetic networks composed of transcriptional factors and epigenetic modulators. However, the molecular mechanisms underlying the function of these regulators are not fully elucidated. Chromodomain helicase DNA-binding protein 4 (Chd4), an ATPase subunit of the nucleosome remodeling and deacetylase (NuRD) complex, is highly expressed in ESCs. However, its function in ESC regulation remains elusive. Here we report that Chd4 is required for the maintenance of ESC self-renewal. RNAi-mediated silencing of Chd4 disrupted self-renewal and up-regulated lineage commitment-associated genes under self-renewal culture conditions. During ESC differentiation in embryoid body formation, we observed significantly stronger induction of differentiation-associated genes in Chd4-deficient cells. The phenotype was different from that caused by the deletion of Mbd3, another subunit of the NuRD complex. Transcriptomic analyses revealed that Chd4 secured ESC identity by controlling the expression of subsets of pluripotency- and differentiation-associated genes. Importantly, Chd4 repressed the transcription of T box protein 3 (Tbx3), a transcription factor with important functions in ESC fate determination. Tbx3 knockdown partially rescued aberrant activation of differentiation-associated genes, especially of endoderm-associated genes, induced by Chd4 depletion. Moreover, we identified an interaction of Chd4 with the histone variant H2A.Z. This variant stabilized Chd4 by inhibiting Chd4 protein degradation through the ubiquitin-proteasome pathway. Collectively, this study identifies the Chd4-Tbx3 axis in controlling ESC fate and a role of H2A.Z in maintaining the stability of Chd4 proteins.


Subject(s)
Autoantigens/metabolism , Cell Differentiation/physiology , Mi-2 Nucleosome Remodeling and Deacetylase Complex/metabolism , Proteolysis , Autoantigens/genetics , Cell Line , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Gene Deletion , Histones/genetics , Histones/metabolism , Human Embryonic Stem Cells/cytology , Humans , Mi-2 Nucleosome Remodeling and Deacetylase Complex/genetics , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/metabolism , Protein Stability , T-Box Domain Proteins/genetics , T-Box Domain Proteins/metabolism
19.
ACS Appl Mater Interfaces ; 8(18): 11796-805, 2016 05 11.
Article in English | MEDLINE | ID: mdl-27104837

ABSTRACT

Making use of a facile and low-cost way for the preparation of a hierarchically organized novel hollow closed-pore silica antireflective coating (CHAR) with tailored optical properties and a mechanical reliability is of great interest in the field of solar photovoltaic technology. The process mainly contains two aspects: (1) a styrene-acrylate emulsion @ organic-inorganic silica precursor (SA@OISP) core/shell hierarchical nanostructure, consisting of a sacrificial styrene-acrylate (SA) primary template, was fabricated using a sol-gel method; (2) the self-assembly of the nanostructures leads to SA@OISP nanospheres forming the high-quality hollow closed-pore silica antireflection coating (CHAR) by a dip-coating process and a subsequent calcination treatment. The resulting SA@OISP nanospheres have a mean diameter of 65.2 nm and contained a SA soft core with a mean diameter of approximately 54.8 nm and an organic-inorganic silica precursor (OISP) shell with a thickness of approximately 6-10 nm. Furthermore, the prepared CHAR film exhibited a high transmittance and good ruggedness. An average transmittance (TAV) of 97.64% was obtained, and the value is close to the ideal single-layered antireflection coating (98.09%) over a broad range of wavelengths (from 380 to 1100 nm). The CHAR film showed a stable TAV, with attenuation values of less than 0.8% and 0.43% after the abrasion test and the damp heat test, respectively. The conversion efficiency of the CHAR coating cover solar modules tends to be increased by 3.75%. The promising results obtained in this study suggest that the CHAR film was considered as an essential component of the solar module and were expected to provide additional solar energy harvest under extreme outdoor climates.

20.
Biomaterials ; 32(25): 5837-46, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21605896

ABSTRACT

Hydroxyapatite-modified titanate nanowire scaffolds as alternative materials for tissue engineering have been developed via a titanate nanowire matrix assisted electrochemical deposition method. The macroporous titanate nanowire matrix on Ti metal was fabricated by a hydrothermal method, and then followed by an electrochemical synthesis of hydroxyapatite nanoparticles on titanate nanowire. The incorporation of titanate nanowire matrix with high oriented hydroxyapatite nanoparticles generates hierarchical scaffolds with highly osteogenic, structural integrity and excellent mechanical performance. As-prepared porous three dimensional interconnected hydroxyapatite-modified titanate nanowire scaffolds, mimicking the nature's extracellular matrix, could provide a suitable microenvironment for tissue cell ingrowth and differentiation. The ceramic titanate nanowire core with HA nanoparticle sheath structure displays superhydrophilicity, which facilitates the cell attachment and proliferation, and induces the in vitro tissue-engineered bone. Human osteoblast-like MG63 cells were cultured on the hydroxyapatite-modified titanate nanowire scaffolds, and the results showed that the scaffolds highly promote the bioactivity, osteoconductivity and osteoblast differentiation.


Subject(s)
Durapatite/chemistry , Nanowires , Titanium/chemistry , Cell Line, Tumor , Humans , Microscopy, Fluorescence
SELECTION OF CITATIONS
SEARCH DETAIL
...