Immunomodulatory activities of human mesenchymal stromal /stem cells (hMSCs) has been widely recognized as the most critical function of hMSCs for exerting its therapeutic effects. However, the ...detailed mechanisms responsible for regulating the immunomodulation of hMSCs still remain largely unknown. Previous studies revealed that the Notch1 protein exerted a pro-immunomodulatory function probably through interacting with the protein(s) subjective to proteasome-mediated protein degradation. The DLC-1 protein represents a well characterized tumor suppressor subjective to proteasome-mediated degradation. However, the detailed signaling pathway of Notch1 and the involvement of DLC-1 in regulating the immunomodulation of hMSCs have not been studied before.
The transfection with cDNA or siRNA into hMSCs assisted by co-culture of hMSCs with peripheral blood mononuclear cells and small molecule inhibitors of signaling proteins, followed by immunoprecipitation, Western blotting, RT-PCR, and flowcytometry, were employed to characterize the Notch1 signaling, to identify DLC-1 as a candidate proteasome-targeted protein, and to characterize DLC-1 signaling pathway and its interaction with the Notch1 signaling, in the regulation of immunomodulation of hMSCs, specifically, the inhibition of pro-inflammatory CD4
-Th1 lymphocytes, and the release of immunomodulatory molecule IDO1.
One-way ANOVA was utilized as a statistical tool to analyze the data presented as means ± SEM of at least three separate experiments.
The present study revealed that the Notch1-Hey1 axis, but not the Notch1-Hes1 axis, was likely responsible for mediating the pro-immunomodulatory function of the Notch1 signaling. The DLC-1 protein was found subjective to proteasome-mediated protein degradation mediated by the DDB1 and FBXW5 E3 ligases and served as an inhibitor of the immunomodulation of hMSCs through inhibiting Rock1, but not Rock2, downstream the DLC-1 signaling. The Notch1 signaling in the Notch1-Hey1 pathway and the DLC-1 signaling in the DLC-1-Rock1-FBXW5 pathway exhibited a mutual exclusion interaction in the regulation of immunomodulation of hMSCs.
The present study uncovers a novel function of DLC-1 tumor suppressor in regulating the immunomodulation of hMSCs. It also proposes a novel mutual exclusion mechanism between the DLC-1 signaling and the Notch1 signaling that is possibly responsible for fine-tuning the immunomodulation of hMSCs with different clinical implications in hMSCs therapy.
We report a sensor combining two distinguishable magnetic nanoprobes (DNA1/Fe3O4 NPs/Thi and DNA2/Fe3O4 NPs/Fc) with target-triggered hybridization chain reaction (HCR) strategy for the simultaneous ...detection of microRNA-141 (miR-141) and microRNA-21 (miR-21). In the presence of targets, the thiol-modified hairpin capture probes (HCP1 and HCP2) specifically hybridize with miR-141 and miR-21 on a gold electrode, leading to the conformation change of HCP1 and HCP2, respectively. The conformation change subsequently triggers HCR to generate plentiful bonding sequences of magnetic nanoprobes. Thus, numerous thionine (Thi) modified DNA1/Fe3O4 NPs/Thi and ferrocene carboxaldehyde (Fc-CHO) modified DNA2/Fe3O4 NPs/Fc are captured by the well-designed HCR, via DNA hybridization respectively, giving rise to the dual magnified response of currents. The increase in the electrochemical currents at different potentials of the two magnetic nanoprobes enables us to simultaneously and quantitatively detect miR-141 and miR-21. Target-triggered HCR increases the amount of captured nanoprobes due to the increasing number of bonding sequences, greatly amplifying the currents of the two magnetic nanoprobes in the presence of targets, and ultimately realizing the dual signal amplification with increased sensitivity. The sensor can be applied for detecting miRNAs in cell lysates, thus, promising to be a clinic diagnosis of cancers by means of simultaneous detection of a variety of miRNA biomarkers.
•Two distinguishable magnetic nanoprobes were synthesized by hydrothermal treatment.•The target-triggered HCR strategy was introduced for sensitive detection of miRNA.•Multiple miRNAs can be assayed simultaneously with good sensitivity, even in the cell lysates.
When comets interacting with solar wind, straight and narrow plasma tails will be often formed. The most remarkable phenomenon of the plasma tails is the disconnection event, in which a plasma tail ...is uprooted from the comet's head and moves away from the comet. In this paper, the interaction process between a comet and solar wind is simulated by using a laser-driven plasma cloud to hit a cylinder obstacle. A disconnected plasma tail is observed behind the obstacle by optical shadowgraphy and interferometry. Our particle-in-cell simulations show that the difference in thermal velocity between ions and electrons induces an electrostatic field behind the obstacle. This field can lead to the convergence of ions to the central region, resulting in a disconnected plasma tail. This electrostatic-field-induced model may be a possible explanation for the disconnection events of cometary tails.
To explore low-pressure-driven nanofiltration (LPDNF) membranes with high permeate flux, a novel preparation route was proposed and investigated. First, an amphiphilic copolymer of poly (methyl ...methacrylate-co-dimethylaminoethyl methacrylate) (P(MMA-co-DMA)) was synthesized via free-radical copolymerization, and then blended with polyvinyl chloride (PVC) to fabricate precursor membranes via non-solvent induced phase separation (NIPS) process. Utilizing the quaternization and cross-linking reaction between p-xylylene dichloride (XDC) and tertiary amine units in PVC/PMMA-co-DMA precursor membranes, positively charged PVC/PMMA-co-DMA LPDNF membranes were obtained. Element alanalysis, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize the composition and morphology of the membranes. Effects of PMMA-co-DMA content and XDC concentration on the LPDNF membranes’ performance were studied and discussed. With the optimized condition, the NF membrane showed the highest salt rejection (R) and water flux (J), e.g., RMgCl2=89.1%, JMgCl2=22.1L/(m2h) and RNaCl=45.1%, JNaCl=27.6L/(m2h) at a pressure of 0.3MPa. Besides, the rejections of the LPDNF membranes for inorganic salts increased in an order of Na2SO4<MgSO4<NaCl<CaCl2<MgCl2. Together with the good stability, PVC/PMMA-co-DMA blend membrane was approved as a promising positively charged LPDNF membranes.
•A novel positively charged nanofiltration membrane was designed.•The membrane was based on PVC/P(DMA-co-MMA) blend precursor.•The membrane was made via quaternization and cross-linking of blend precursor.•The membrane showed good permeation and rejection for salts.
This article summarizes the recent activity of the International Stem Cell Banking Initiative (ISCBI) held at the California Institute for Regenerative Medicine (CIRM) in California (June 26, 2016) ...and the Korean National Institutes for Health in Korea (October 19–20, 2016). Through the workshops, ISCBI is endeavoring to support a new paradigm for human medicine using pluripotent stem cells (hPSC) for cell therapies. Priority considerations for ISCBI include ensuring the safety and efficacy of a final cell therapy product and quality assured source materials, such as stem cells and primary donor cells. To these ends, ISCBI aims to promote global harmonization on quality and safety control of stem cells for research and the development of starting materials for cell therapies, with regular workshops involving hPSC banking centers, biologists, and regulatory bodies. Here, we provide a brief overview of two such recent activities, with summaries of key issues raised. Stem Cells Translational Medicine 2017;6:1956–1962
This article reviews recent discussions among world leading groups working on provision of stem cell lines for research and clinical use. ISCBI confirmed the need for standards of quality control, safety, ethics, and resource sharing.
Abstract
Background
Sewage transmission of SARS-CoV-2 has never been demonstrated. During a COVID-19 outbreak in Guangzhou, China in April 2020, we investigated the mode of transmission.
Methods
We ...collected clinical and environmental samples from quarantined residents and their environment for RT-PCR testing and genome sequencing. A case was a resident with a positive RT-PCR test regardless of symptoms. We conducted a retrospective cohort study of all residents of cases’ buildings to identify risk factors.
Results
We found 8 cases (onset: 5–21 April). During incubation period, cases 1 and 2 frequented market T where a COVID-19 outbreak was ongoing; cases 3–8 never visited market T, lived in separate buildings and never interacted with cases 1 and 2. Working as a janitor or wastepicker (RR = 13; 95% CIexact, 2.3–180), not changing to clean shoes (RR = 7.4; 95% CIexact, 1.8–34) and handling dirty shoes by hand (RR = 6.3; 95% CIexact, 1.4–30) after returning home were significant risk factors. RT-PCR detected SARS-CoV-2 in 19% of 63 samples from sewage puddles or pipes, and 24% of 50 environmental samples from cases’ apartments. Viruses from the squat toilet and shoe-bottom dirt inside the apartment of cases 1 and 2 were homologous with those from cases 3–8 and the sewage. Sewage from the apartment of cases 1 and 2 leaked out of a cracked pipe onto streets. Rainfall after the onset of cases 1 and 2 flooded the streets.
Conclusions
SARS-CoV-2 might spread by sewage, highlighting the importance of sewage management during outbreaks.
Accumulating evidence shows that agents targeting gut dysbiosis are effective for improving symptoms of irritable bowel syndrome (IBS). However, the potential mechanisms remain unclear. In this study ...we investigated the effects of berberine on the microbiota-gut-brain axis in two rat models of visceral hypersensitivity, i.e., specific pathogen-free SD rats subjected to chronic water avoidance stress (WAS) and treated with berberine (200 mg· kg
·d
, ig, for 10 days) as well as germ-free (GF) rats subjected to fecal microbiota transplantation (FMT) from a patient with IBS (designated IBS-FMT) and treated with berberine (200 mg· kg
·d
, ig, for 2 weeks). Before the rats were sacrificed, visceral sensation and depressive behaviors were evaluated. Then colonic tryptase was measured and microglial activation in the dorsal lumbar spinal cord was assessed. The fecal microbiota was profiled using 16S rRNA sequencing, and short chain fatty acids (SCFAs) were measured. We showed that berberine treatment significantly alleviated chronic WAS-induced visceral hypersensitivity and activation of colonic mast cells and microglia in the dorsal lumbar spinal cord. Transfer of fecal samples from berberine-treated stressed donors to GF rats protected against acute WAS. FMT from a patient with IBS induced visceral hypersensitivity and pro-inflammatory phenotype in microglia, while berberine treatment reversed the microglial activation and altered microbial composition and function and SCFA profiles in stools of IBS-FMT rats. We demonstrated that berberine did not directly influence LPS-induced microglial activation in vitro. In both models, several SCFA-producing genera were enriched by berberine treatment, and positively correlated to the morphological parameters of microglia. In conclusion, activation of microglia in the dorsal lumbar spinal cord was involved in the pathogenesis of IBS caused by dysregulation of the microbiota-gut-brain axis, and the berberine-altered gut microbiome mediated the modulatory effects of the agent on microglial activation and visceral hypersensitivity, providing a potential option for the treatment of IBS.
CD4
T cell helper and regulatory function in human cancers has been well characterised. However, the definition of tumor-infiltrating CD4
T cell exhaustion and how it contributes to the immune ...response and disease progression in human gastric cancer (GC) remain largely unknown.
A total of 128 GC patients were enrolled in the study. The expression of CD39 and PD-1 on CD4
T cells in the different samples was analysed by flow cytometry. GC-infiltrating CD4
T cell subpopulations based on CD39 expression were phenotypically and functionally assessed. The role of CD39 in the immune response of GC-infiltrating T cells was investigated by inhibiting CD39 enzymatic activity.
In comparison with CD4
T cells from the non-tumor tissues, significantly more GC-infiltrating CD4
T cells expressed CD39. Most GC-infiltrating CD39
CD4
T cells exhibited CD45RA
CCR7
effector-memory phenotype expressing more exhaustion-associated inhibitory molecules and transcription factors and produced less TNF-α, IFN-γ and cytolytic molecules than their CD39
CD4
counterparts. Moreover,
inhibition of CD39 enzymatic activity enhanced their functional potential reflected by TNF-α and IFN-γ production. Finally, increased percentages of GC-infiltrating CD39
CD4
T cells were positively associated with disease progression and patients' poorer overall survival.
Our study demonstrates that CD39 expression defines GC-infiltrating CD4
T cell exhaustion and their immunosuppressive function. Targeting CD39 may be a promising therapeutic strategy for treating GC patients.
We propose a ratiometric electrochemical assay for detecting microRNA (miRNA) on the basis of dual-amplification mechanism by using distinguishable electrochemical signals from thionine (Thi) and ...ferrocene (Fc). The thiol-modified and ferrocene-labeled hairpin capture probes (CP) are first immobilized on an Au electrode via Au-S reaction. The target miRNA hybridizes with CP and unfolding the hairpin structure of CP to form miRNA-DNA duplexes. Then, kamchatka crab duplex specific nuclease (DSN) specifically cleaves the DNA in miRNA-DNA duplexes, leading to the release of miRNA and another cleaves cycle, meanwhile, numerous Fc leaves away from the electrode surface and leads to the signal-off of Fc. The residual fragment on electrode surface acts as a HCR primer to form dsDNA polymers through in situ HCR with the presence of the primer and two probes (HDNA and HDNA’), resulting in the capture of numerous DNA/Au NPs/Thi and the signal-on of Thi. The dual-amplification mechanism significantly amplifies the decrease of Fc signal and the increase of Thi signal for ratiometric readout (IThi/IFc), thus providing a sensitive method for the selective detection of miR-141 with a detection limit down to 11aM. The dual-signal ratiometric outputs have an intrinsic self-calibration to the effects from system, which is promising to be applied in biosensing and clinical diagnosis.
•The miRNA-initiated cleavage of DNA by DSN was introduced for a signal-off of Fc.•HCR and the nanoprobes can masterly amplify the signal-on of Thi.•The dual-amplification mechanism further amplified the ratiometric readout of IThi/IFc.•This ratiometric miRNA nanosensor was constructed based on DSN, HCR and nanoprobes.
A selective oxy-difluoroalkylation of allylamines with carbon dioxide (CO2) via visible-light photoredox catalysis is reported. These multicomponent reactions are efficient and environmentally ...friendly to generate a series of important 2-oxazolidinones with functionalized difluoroalkyl groups. The good functional group tolerance, broad substrate scope, easy scalability, mild reaction conditions, and facile functionalization of products provide great potential for application in organic synthesis and pharmaceutical chemistry.
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