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1.
J Immunol ; 212(12): 1932-1944, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38709167

RESUMO

IFN regulatory factor 7 (IRF7) exerts anti-infective effects by promoting the production of IFNs in various bacterial and viral infections, but its role in highly morbid and fatal Candida albicans infections is unknown. We unexpectedly found that Irf7 gene expression levels were significantly upregulated in tissues or cells after C. albicans infection in humans and mice and that IRF7 actually exacerbates C. albicans infection in mice independent of its classical function in inducing IFNs production. Compared to controls, Irf7-/- mice showed stronger phagocytosis of fungus, upregulation of C-type lectin receptor CD209 expression, and enhanced P53-AMPK-mTOR-mediated autophagic signaling in macrophages after C. albicans infection. The administration of the CD209-neutralizing Ab significantly hindered the phagocytosis of Irf7-/- mouse macrophages, whereas the inhibition of p53 or autophagy impaired the killing function of these macrophages. Thus, IRF7 exacerbates C. albicans infection by compromising the phagocytosis and killing capacity of macrophages via regulating CD209 expression and p53-AMPK-mTOR-mediated autophagy, respectively. This finding reveals a novel function of IRF7 independent of its canonical IFNs production and its unexpected role in enhancing fungal infections, thus providing more specific and effective targets for antifungal therapy.


Assuntos
Autofagia , Candida albicans , Candidíase , Fator Regulador 7 de Interferon , Lectinas Tipo C , Macrófagos , Camundongos Knockout , Fagocitose , Receptores de Superfície Celular , Serina-Treonina Quinases TOR , Animais , Camundongos , Fagocitose/imunologia , Autofagia/imunologia , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Candidíase/imunologia , Candida albicans/imunologia , Candida albicans/fisiologia , Fator Regulador 7 de Interferon/genética , Fator Regulador 7 de Interferon/metabolismo , Fator Regulador 7 de Interferon/imunologia , Macrófagos/imunologia , Humanos , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Camundongos Endogâmicos C57BL , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Transdução de Sinais/imunologia
2.
Cell Mol Life Sci ; 81(1): 280, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38918243

RESUMO

Candida albicans is among the most prevalent invasive fungal pathogens for immunocompromised individuals and novel therapeutic approaches that involve immune response modulation are imperative. Absent in melanoma 2 (AIM2), a pattern recognition receptor for DNA sensing, is well recognized for its involvement in inflammasome formation and its crucial role in safeguarding the host against various pathogenic infections. However, the role of AIM2 in host defense against C. albicans infection remains uncertain. This study reveals that the gene expression of AIM2 is induced in human and mouse innate immune cells or tissues after C. albicans infection. Furthermore, compared to their wild-type (WT) counterparts, Aim2-/- mice surprisingly exhibit resistance to C. albicans infection, along with reduced inflammation in the kidneys post-infection. The resistance of Aim2-/- mice to C. albicans infection is not reliant on inflammasome or type I interferon production. Instead, Aim2-/- mice display lower levels of apoptosis in kidney tissues following infection than WT mice. The deficiency of AIM2 in macrophages, but not in dendritic cells, results in a phenocopy of the resistance observed in Aim2-/- mice against C. albican infection. The treatment of Clodronate Liposome, a reagent that depletes macrophages, also shows the critical role of macrophages in host defense against C. albican infection in Aim2-/- mice. Furthermore, the reduction in apoptosis is observed in Aim2-/- mouse macrophages following infection or treatment of DNA from C. albicans in comparison with controls. Additionally, higher levels of AKT activation are observed in Aim2-/- mice, and treatment with an AKT inhibitor reverses the host resistance to C. albicans infection. The findings collectively demonstrate that AIM2 exerts a negative regulatory effect on AKT activation and enhances macrophage apoptosis, ultimately compromising host defense against C. albicans infection. This suggests that AIM2 and AKT may represent promising therapeutic targets for the management of fungal infections.


Assuntos
Apoptose , Candida albicans , Candidíase , Proteínas de Ligação a DNA , Macrófagos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Animais , Macrófagos/metabolismo , Macrófagos/imunologia , Macrófagos/microbiologia , Candidíase/imunologia , Candidíase/microbiologia , Candidíase/metabolismo , Candidíase/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Camundongos , Humanos , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Inflamassomos/metabolismo , Imunidade Inata , Rim/patologia , Rim/metabolismo , Rim/microbiologia
3.
Opt Express ; 31(6): 10191-10200, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-37157572

RESUMO

Mn2+ doped lead-free double perovskites are emerging afterglow materials that can avoid the usage of rare earth ions. However, the regulation of the afterglow time is still a challenge. In this work, the Mn doped Cs2Na0.2Ag0.8InCl6 crystals with afterglow emission at about 600 nm are synthesized by a solvothermal method. Then, the Mn2+ doped double perovskite crystals are crushed into different sizes. As the size decreases from 1.7 mm to 0.075 mm, the afterglow time decreases from 2070 s to 196 s. Steady-state photoluminescence (PL) spectra, time resolved PL, thermoluminescence (TL) reveal the afterglow time monotonously decreases due to the enhanced nonradiative surface trapping. The modulation on afterglow time will greatly promote their applications in various fields, such as bioimaging, sensing, encryption, and anti-counterfeiting. As a proof of concept, dynamic display of information is realized based on different afterglow times.

4.
Cytotherapy ; 24(7): 733-741, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35461759

RESUMO

Most clinically evaluated chimeric antigen receptor (CAR)-based cell therapies are generated from autologous immune cells. However, there are several limitations to autologous cell therapy, including low availability, poor quality of starting cellular material and limited expansion capability. Recently, induced pluripotent stem cell (iPSC)-derived allogeneic cell therapy platforms have gained popularity, as they seek to overcome many of the challenges inherent to current autologous cell therapies. However, teratoma risk associated with residual undifferentiated cells (i.e., iPSCs) in the drug product may restrict potential clinical applications if left unaddressed. To ensure the safety of the final cell therapy product, there is a need to develop quality control assays to detect residual iPSCs. Combining microRNA (miRNA) sequencing data with publicly archived miRNA microarray datasets, we demonstrated that miRNAs belonging to the 300 family (miR-302a-5p, miR-302c-3p and miR-302d-5p) and 500 family (miR-518f-5p and miR-519-3p) were highly expressed in iPSCs (both periperal blood mononuclear cell- and T cell-derived iPSCs) compared with a number of differentiated cell types. We developed and validated a sensitive digital droplet polymerase chain reaction (ddPCR) assay targeting these miRNAs to detect low levels of residual iPSCs in differentiated cell samples. The miRNA ddPCR-based method with primers for miR-302a-5p, miR-302c-3p and miR-302d-5p detected as few as 5, 3 and 10 undifferentiated iPSCs, respectively, in the background of 106 iPSC-derived natural killer (iNK) cells. These results suggest that our method targeting identified iPSC-specific miRNA transcripts is specific and sensitive for the quality assessment of NK cell therapy products derived from iPSCs.


Assuntos
Células-Tronco Pluripotentes Induzidas , MicroRNAs , Diferenciação Celular/genética , Terapia Baseada em Transplante de Células e Tecidos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Matadoras Naturais/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo
5.
Nature ; 532(7597): 107-11, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26982723

RESUMO

Diploidy is a fundamental genetic feature in mammals, in which haploid cells normally arise only as post-meiotic germ cells that serve to ensure a diploid genome upon fertilization. Gamete manipulation has yielded haploid embryonic stem (ES) cells from several mammalian species, but haploid human ES cells have yet to be reported. Here we generated and analysed a collection of human parthenogenetic ES cell lines originating from haploid oocytes, leading to the successful isolation and maintenance of human ES cell lines with a normal haploid karyotype. Haploid human ES cells exhibited typical pluripotent stem cell characteristics, such as self-renewal capacity and a pluripotency-specific molecular signature. Moreover, we demonstrated the utility of these cells as a platform for loss-of-function genetic screening. Although haploid human ES cells resembled their diploid counterparts, they also displayed distinct properties including differential regulation of X chromosome inactivation and of genes involved in oxidative phosphorylation, alongside reduction in absolute gene expression levels and cell size. Surprisingly, we found that a haploid human genome is compatible not only with the undifferentiated pluripotent state, but also with differentiated somatic fates representing all three embryonic germ layers both in vitro and in vivo, despite a persistent dosage imbalance between the autosomes and X chromosome. We expect that haploid human ES cells will provide novel means for studying human functional genomics and development.


Assuntos
Diferenciação Celular , Estudos de Associação Genética/métodos , Haploidia , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Autorrenovação Celular , Separação Celular , Tamanho Celular , Cromossomos Humanos X/genética , Diploide , Regulação para Baixo/genética , Deleção de Genes , Camadas Germinativas/citologia , Humanos , Cariotipagem , Oócitos/metabolismo , Fosforilação Oxidativa , Partenogênese , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Inativação do Cromossomo X/genética
6.
EMBO J ; 34(7): 841-55, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25733347

RESUMO

The discovery of insulin more than 90 years ago introduced a life-saving treatment for patients with type 1 diabetes, and since then, significant progress has been made in clinical care for all forms of diabetes. However, no method of insulin delivery matches the ability of the human pancreas to reliably and automatically maintain glucose levels within a tight range. Transplantation of human islets or of an intact pancreas can in principle cure diabetes, but this approach is generally reserved for cases with simultaneous transplantation of a kidney, where immunosuppression is already a requirement. Recent advances in cell reprogramming and beta cell differentiation now allow the generation of personalized stem cells, providing an unlimited source of beta cells for research and for developing autologous cell therapies. In this review, we will discuss the utility of stem cell-derived beta cells to investigate the mechanisms of beta cell failure in diabetes, and the challenges to develop beta cell replacement therapies. These challenges include appropriate quality controls of the cells being used, the ability to generate beta cell grafts of stable cellular composition, and in the case of type 1 diabetes, protecting implanted cells from autoimmune destruction without compromising other aspects of the immune system or the functionality of the graft. Such novel treatments will need to match or exceed the relative safety and efficacy of available care for diabetes.


Assuntos
Reprogramação Celular/imunologia , Terapia de Imunossupressão , Células Secretoras de Insulina , Transplante das Ilhotas Pancreáticas/imunologia , Imunologia de Transplantes , Animais , Autoenxertos , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 1/terapia , Humanos , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/transplante , Transplante de Rim
7.
Small ; 14(5)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29251420

RESUMO

Nitrogen-doped graphene (NG) with wrinkled and bubble-like texture is fabricated by a thermal treatment. Especially, a novel sonication-assisted pretreatment with nitric acid is used to further oxidize graphene oxide and its binding with melamine molecules. There are many bubble-like nanoflakes with a dimension of about 10 nm appeared on the undulated graphene nanosheets. The bubble-like texture provides more active sites for effective ion transport and reversible capacitive behavior. The specific surface area of NG (5.03 at% N) can reach up to 438.7 m2 g-1 , and the NG electrode demonstrates high specific capacitance (481 F g-1 at 1 A g-1 , four times higher than reduced graphene oxide electrode (127.5 F g-1 )), superior cycle stability (the capacitance retention of 98.9% in 2 m KOH and 99.2% in 1 m H2 SO4 after 8000 cycles), and excellent energy density (42.8 Wh kg-1 at power density of 500 W kg-1 in 2 m KOH aqueous electrolyte). The results indicate the potential use of NG as graphene-based electrode material for energy storage devices.

8.
Inflammation ; 47(1): 191-208, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37740789

RESUMO

Candida albicans is a common opportunistic pathogenic fungus. The innate immune system provides the first-line host defense against fungal infection. Innate immune receptors and downstream molecules have been shown to play various roles during fungal infection. The innate immune receptor MDA5, encoded by the gene Ifih1, enhances host resistance against viral and Aspergillus fumigatus infection by inducing the production of interferons (IFNs). However, the role of MDA5 in C. albicans infection is still unclear. Here, we found that the gene expression levels of IFIH1 were significantly increased in innate immune cells after C. albicans stimulation through human bioinformatics analysis or mouse experiments. Through in vivo study, MDA5 was shown to enhance host susceptibility to C. albicans infection independent of IFN production. Instead, MDA5 exerted its influence on macrophages and kidneys by modulating the expression of Noxa, Bcl2, and Bax, thereby promoting apoptosis. Additionally, MDA5 compromised killing capabilities of macrophage by inhibition iNOS expression. The introduction of the apoptosis inducer PAC1 further impaired macrophage functions, mimicking the enhancing effect of MDA5 on C. albicans infection. Furthermore, the administration of macrophage scavengers increased the susceptibility of Ifih1-/- mice to C. albicans. The founding suggests that MDA5 promote host susceptibility to invasive C. albicans by enhancing cell apoptosis and compromising macrophage functions, making MDA5 a target to treat candidiasis.


Assuntos
Candida albicans , Candidíase , Animais , Humanos , Camundongos , Apoptose , Candida albicans/fisiologia , Helicase IFIH1 Induzida por Interferon , Macrófagos , Fagocitose
9.
J Adv Res ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38964734

RESUMO

INTRODUCTION: Intestinal immune dysregulation is strongly linked to the occurrence and formation of tumors. RING finger protein 128 (RNF128) has been identified to play distinct immunoregulatory functions in innate and adaptive systems. However, the physiological roles of RNF128 in intestinal inflammatory conditions such as colitis and colorectal cancer (CRC) remain controversial. OBJECTIVES: To elucidate the function and mechanism of RNF128 in colitis and CRC. METHODS: Animal models of dextran sodium sulfate (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced CRC were established in WT and Rnf128-deficient mice and evaluated by histopathology. Co-immunoprecipitation and ubiquitination analyses were employed to investigate the role of RNF128 in IL-6-STAT3 signaling. RESULTS: RNF128 was significantly downregulated in clinical CRC tissues compared with paired peritumoral tissues. Rnf128-deficient mice were hypersusceptible to both colitis induced by DSS and CRC induced by AOM/DSS or APC mutation. Loss of RNF128 promoted the proliferation of CRC cells and STAT3 activation during the early transformative stage of carcinogenesis in vivo and in vitro when stimulated by IL-6. Mechanistically, RNF128 interacted with the IL-6 receptor α subunit (IL-6Rα) and membrane glycoprotein gp130 and mediated their lysosomal degradation in ligase activity-dependent manner. Through a series of point mutations in the IL-6 receptor, we identified that RNF128 promoted K48-linked polyubiquitination of IL-6Rα at K398/K401 and gp130 at K718/K816/K866. Additionally, blocking STAT3 activation effectively eradicated the inflammatory damage of Rnf128-deficient mice during the transformative stage of carcinogenesis. CONCLUSION: RNF128 attenuates colitis and colorectal tumorigenesis by inhibiting IL-6-STAT3 signaling, which sheds novel insights into the modulation of IL-6 receptors and the inflammation-to-cancer transition.

10.
Mol Metab ; 80: 101879, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38237895

RESUMO

OBJECTIVE: Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM), requiring insulin therapy similar to T1D. While the negative effects on insulin processing and secretion are known, how dominant insulin mutations result in a continued decline of beta cell function after birth is not well understood. METHODS: We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations using patient-derived iPSCs and mutated hESCs. RESULTS: we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on beta-cell mass and function after transplantation into mice. In addition to anticipated ER stress, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon. CONCLUSIONS: These results highlight a novel mechanism, the loss of beta cell identity, contributing to the loss and functional failure of human beta cells with specific insulin gene mutations.


Assuntos
Diabetes Mellitus , Insulina , Humanos , Animais , Camundongos , Insulina/genética , Proinsulina/genética , Diabetes Mellitus/genética , Mutação/genética , Insulina Regular Humana/genética
11.
Phys Chem Chem Phys ; 15(42): 18716-20, 2013 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-24071636

RESUMO

TiO2 has been extensively investigated due to its unique photoelectric properties. In this study, oriented single-crystal rutile TiO2 nanorod arrays were synthesized and then calcined at different temperatures in the atmosphere. The morphology and crystalline characterization indicated that the length of TiO2 nanorods increased rapidly and the nanorods became aggregated and fragile after calcination, yet the sintering treatment seemed to have almost no effect on the crystallinity. To obtain the all-solid-state, dye-sensitized solar cells (DSSCs), a newly reported solid inorganic semiconductor, CsSnI2.95F0.05, was employed as the electrolyte, and the Pt deposited on the conductive side of the fluorine-doped tin oxide (FTO) glass substrate was used as the counter-electrode. The effects of the calcination treatment on the photoelectric properties of the solar cells, including external quantum efficiency (EQE), open circuit voltage (V(OC)), short-circuit current (J(SC)), and photoelectric conversion efficiency (η), were investigated under the illumination of a solar simulator. As a result, all of the EQE, V(OC), J(SC), and η values of the cells first increased and then declined with the increase of calcination temperatures, and the highest η of 2.81% was obtained by the cell assembled with its TiO2 electrode sintered at 450 °C for 3 h, a value almost 2.5 times that of the non-sintered sample (1.1%).

12.
Med Oncol ; 41(1): 34, 2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38150048

RESUMO

Colorectal cancer (CRC) is a prevalent cause of cancer and mortality on a global scale. SNAI1, a member of the zinc finger transcription superfamily, is a significant contributor to embryonic development and carcinogenesis through the process of epithelial-mesenchymal transition (EMT). While prior research utilizing CRC cells and clinical data has demonstrated that SNAI1 facilitates CRC progression through diverse mechanisms, the precise manner in which epithelial SNAI1 regulates CRC development in vivo remains unclear. In this study, colitis and colitis-associated CRC were induced through the use of intestinal epithelium-specific Snai1 knockout (Snai1 cKO) mice. Our findings indicate that Snai1 cKO mice exhibit a reduced susceptibility to acute colitis and colitis-associated CRC compared to control mice. Western-blot analysis of colon tissues revealed that Snai1 cKO mice exhibited a higher overall apoptosis level during tumor formation than control mice. No significant differences were observed in the activation of the classical p53 signaling pathway. However, Snai1 cKO mice exhibited weakened EMT and Wnt/ß-catenin pathway activation. In summary, our study has provided evidence in vivo that the intestinal epithelial SNAI1 protein suppresses apoptosis, amplifies the EMT, and activates the Wnt/ß-catenin signaling pathways in both early and late phases of CRC formation, thus promoting the development and progression of colitis-associated CRC.


Assuntos
Colite , Neoplasias Colorretais , Animais , Feminino , Camundongos , Gravidez , beta Catenina/genética , Colite/complicações , Colite/genética , Neoplasias Colorretais/genética , Transição Epitelial-Mesenquimal , Via de Sinalização Wnt
13.
Cells ; 12(6)2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36980244

RESUMO

The rare SLC30A8 mutation encoding a truncating p.Arg138* variant (R138X) in zinc transporter 8 (ZnT8) is associated with a 65% reduced risk for type 2 diabetes. To determine whether ZnT8 is required for beta cell development and function, we derived human pluripotent stem cells carrying the R138X mutation and differentiated them into insulin-producing cells. We found that human pluripotent stem cells with homozygous or heterozygous R138X mutation and the null (KO) mutation have normal efficiency of differentiation towards insulin-producing cells, but these cells show diffuse granules that lack crystalline zinc-containing insulin granules. Insulin secretion is not compromised in vitro by KO or R138X mutations in human embryonic stem cell-derived beta cells (sc-beta cells). Likewise, the ability of sc-beta cells to secrete insulin and maintain glucose homeostasis after transplantation into mice was comparable across different genotypes. Interestingly, sc-beta cells with the SLC30A8 KO mutation showed increased cytoplasmic zinc, and cells with either KO or R138X mutation were resistant to apoptosis when extracellular zinc was limiting. These findings are consistent with a protective role of zinc in cell death and with the protective role of zinc in T2D.


Assuntos
Proteínas de Transporte de Cátions , Diabetes Mellitus Tipo 2 , Células-Tronco Embrionárias Humanas , Transportador 8 de Zinco , Zinco , Animais , Humanos , Camundongos , Apoptose/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo , Células-Tronco Embrionárias Humanas/fisiologia , Insulina/metabolismo , Mutação com Perda de Função , Mutação/genética , Zinco/metabolismo , Transportador 8 de Zinco/genética , Transportador 8 de Zinco/metabolismo
14.
J Colloid Interface Sci ; 649: 685-693, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37385033

RESUMO

Constructing semiconductor heterojunctions can enable novel schemes for highly efficient photocatalytic activity. However, introducing strong covalent bonding at the interface remains an open challenge. Herein, ZnIn2S4 (ZIS) with abundant sulfur vacancies (Sv) is synthesized with the presence of PdSe2 as an additional precursor. The sulfur vacancies of Sv-ZIS are filled by Se atoms of PdSe2, leading to the Zn-In-Se-Pd compound interface. Our density functional theory (DFT) calculations reveal the increased density of states at the interface, which will increase the local carrier concentration. Moreover, the length of the Se-H bond is longer than that of the SH bond, which is good for the evolution of H2 from the interface. In addition, the charge redistribution at the interface results in a built-in field, providing the driving force for efficient separation of photogenerated electron-hole. Therefore, the PdSe2/Sv-ZIS heterojunction with strong covalent interface exhibits an excellent photocatalytic hydrogen evolution performance (4423 µmol g-1h-1) with an apparent quantum efficiency (λ > 420 nm) of 9.1 %. This work will provide new inspirations to improve photocatalytic activity by engineering the interfaces of semiconductor heterojunctions.

15.
Sci Transl Med ; 15(681): eabq4126, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36724243

RESUMO

Sulfonylureas (SUs) are effective and affordable antidiabetic drugs. However, chronic use leads to secondary failure, limiting their utilization. Here, we identify cytochrome b5 reductase 3 (Cyb5r3) down-regulation as a mechanism of secondary SU failure and successfully reverse it. Chronic exposure to SU lowered Cyb5r3 abundance and reduced islet glucose utilization in mice in vivo and in ex vivo murine islets. Cyb5r3 ß cell-specific knockout mice phenocopied SU failure. Cyb5r3 engaged in a glucose-dependent interaction that stabilizes glucokinase (Gck) to maintain glucose utilization. Hence, Gck activators can circumvent Cyb5r3-dependent SU failure. A Cyb5r3 activator rescued secondary SU failure in mice in vivo and restored insulin secretion in ex vivo human islets. We conclude that Cyb5r3 is a key factor in the secondary failure to SU and a potential target for its prevention, which might rehabilitate SU use in diabetes.


Assuntos
Diabetes Mellitus , Células Secretoras de Insulina , Camundongos , Humanos , Animais , Compostos de Sulfonilureia/farmacologia , Compostos de Sulfonilureia/uso terapêutico , Glucose , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Citocromo-B(5) Redutase
16.
bioRxiv ; 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37745320

RESUMO

Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM) that results from beta cell failure. We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations. Using b and mutated hESCs, we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on the in vivo performance of patient-derived SC-beta cells after transplantation into NSG mice. These insulin mutations derange endoplasmic reticulum (ER) homeostasis, and result in the loss of beta-cell mass and function. In addition to anticipated apoptosis, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon. These results highlight both known and novel mechanisms contributing to the loss and functional failure of human beta cells with specific insulin gene mutations.

17.
Biochem Biophys Res Commun ; 426(3): 380-5, 2012 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-22960178

RESUMO

Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study, we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.


Assuntos
Ativinas/farmacologia , Células-Tronco Embrionárias/efeitos dos fármacos , Endoderma/citologia , Fatores de Crescimento de Fibroblastos/fisiologia , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Contagem de Células , Linhagem Celular , Meios de Cultura Livres de Soro/farmacologia , Células-Tronco Embrionárias/citologia , Fatores de Crescimento de Fibroblastos/farmacologia , Humanos , Pâncreas/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais
18.
J Colloid Interface Sci ; 612: 88-96, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-34979413

RESUMO

Solar desalination is considered as a promising approach to solve the shortage of fresh water resources. In this work, inspired by the transpiration of trees, a self-floating and integrated bionic mushroom solar steam generator (BMSSG) is proposed for highly efficient water evaporation. A wooden strip is used to mimic the stipe of the mushroom for water transportation, meanwhile polyvinyl alcohol (PVA) modified graphene aerogels (GA) is used to imitate the pileus of the mushroom for photothermal conversion. After optimizing compositions of the aerogel and sizes of the wooden strip, a high evaporation rate of 1.67 kg m-2h-1 is obtained, outcompeting most of other wood-based evaporators. Compared to traditional interfacial evaporation devices, BMSSG is an integrated structure without a thermal insulation layer and an absorbent wick, which not only increases the compactness that is good for stability and reliability, but also reduces the manufacturing cost. Moreover, the BMSSG can self-float on the water like a roly-poly. These advantages indicate that BMSSG will play a significant role in seawater desalination. The feasibility as well as stability and recyclability of the BMSSG for seawater desalination are demonstrated. This bioinspired design provides a low-cost and scalable SSG, which will have a profound impact in future practical applications.


Assuntos
Agaricales , Purificação da Água , Biônica , Reprodutibilidade dos Testes , Vapor
19.
Nanomaterials (Basel) ; 12(22)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36432266

RESUMO

The introduction of impure atoms or crystal defects is a promising strategy for enhancing the photocatalytic activity of semiconductors. However, the synergy of these two effects in 2D atomic layers remains unexplored. In this case, the preparation of molybdenum-doped thin ZnIn2S4-containing S vacancies (Mo-doped Sv-ZnIn2S4) is conducted using a one-pot solvothermal method. The coordination of Mo doping and S vacancies not only enhances visible light absorption and facilitates the separation of photogenerated carriers but also provides many active sites for photocatalytic reactions. Meanwhile, the Mo-S bonds play function as high-speed channels to rapidly transfer carriers to the active sites, which can directly promote hydrogen evolution. Consequently, Sv-ZnIn2S4 with an optimized amount of Mo doping exhibits a high hydrogen evolution rate of 5739 µmol g-1 h-1 with a corresponding apparent quantum yield (AQY) of 21.24% at 420 nm, which is approximately 5.4 times higher than the original ZnIn2S4. This work provides a new strategy for the development of highly efficient and sustainable 2D atomic photocatalysts for hydrogen evolution.

20.
J Colloid Interface Sci ; 608(Pt 1): 284-293, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34626975

RESUMO

The emergence of two dimensional (2D) nanosheets provides flexible platforms for the construction of semiconductor heterostructures for photocatalytic hydrogen evolution. However, the compact and conformal contact between the components with different dimensions remains challenge. Herein, we anchor the 2D layered black phosphorous quantum dots (BPQDs) onto the 2D ZnIn2S4 nanosheets with sulfur vacancies (V-ZIS). This unique interface between 2D layered QDs and 2D nanosheets ensures a sufficient contact area between the BPQDs and the V-ZIS, which is conducive to the transport and the spatial separation of photogenerated electrons and holes. A synergistic effect of sulfur vacancies and type-Ⅱ heterojunction results in an excellent photocatalytic hydrogen evolution performance of the BPQDs/V-ZIS composites. The hydrogen evolution rate by the BPQDs/V-ZIS without any noble-metal as cocatalyst is up to 5079 µmol g-1h-1 under visible light irradiation with an apparent quantum yield (AQY) of 12.03% at 420 nm, which is dramatically higher than most other photocatalysts reported previously.

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