Publications by authors named "Wenbo Chen"

153 Publications

SRC-3 deficiency protects host from Listeria monocytogenes infection through increasing ROS production and decreasing lymphocyte apoptosis.

Int Immunopharmacol 2021 Apr 12;96:107625. Epub 2021 Apr 12.

Department of Cardiology, The First Affiliated Hospital of Xiamen University, Xiamen, China. Electronic address:

Listeria monocytogenes is the third major cause of death among food poisoning. Our previous studies have demonstrated that steroid receptor coactivator 3 (SRC-3) plays a critical protective role in host defense against extracellular bacterial pathogens such as Escherichia coli and Citrobacter rodentium. However, its role involved in intracellular bacterial pathogen infection remains unclear. Herein, we found that SRC-3 mice are more resistant to L. monocytogenes infection after tail intravenous injection with L. monocytogenes compared with wild-type mice. After infecting with L. monocytogenes, SRC-3 mice exhibited decreased mortality rate, decreased bacterial load, less body weight loss, less proinflammatory cytokines and less severe tissue damage compared with wild-type mice. SRC-3 mice produced more ROS and decreased L. monocytogenes-induced lymphocyte apoptosis. Mechanically, SRC-3 mice displayed decreased expressions of negative regulator of ROS (NRROS) and interferon (IFN)-β and its target genes such as Daxx, Mx1 and TRAIL associated with apoptosis. Taken together, SRC-3 deficiency can protect host from L. monocytogenes infection through increasing ROS production and decreasing lymphocyte apoptosis via affecting the expressions of NRROS and IFN-β.
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http://dx.doi.org/10.1016/j.intimp.2021.107625DOI Listing
April 2021

A whole-body circulatory neutrophil model with application to predicting clinical neutropenia from in vitro studies.

CPT Pharmacometrics Syst Pharmacol 2021 Apr 1. Epub 2021 Apr 1.

Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.

A circulatory model of granulopoiesis and its regulation is presented that includes neutrophil trafficking in lung, liver, spleen, bone marrow, lymph node and blood. In each organ, neutrophils undergo transendothelial migration from vascular to interstitial space, clearance due to apoptosis, and recycling via the lymphatic flow. The model includes cell cycling of progenitor cells in the bone marrow, granulocyte-colony stimulating factor (G-CSF) kinetics and its neutrophil regulatory action, as well as neutrophil margination in the blood. From previously reported studies, In-labeled neutrophil kinetic data in the blood and sampled organs were used to estimate the organ trafficking parameters in the model. The model was further developed and evaluated using absolute neutrophil count (ANC), band cell, and segmented neutrophil time course data from healthy volunteers following four dose levels of pegfilgrastim (r =0.77 to 0.99), along with ANC time course responses following filgrastim (r =0.96). The baseline values of various cell types in bone marrow and blood, as well as G-CSF concentration in the blood, predicted by the model are consistent with available literature reports. After incorporating the mechanism of action of both paclitaxel and carboplatin as determined from an in vitro bone marrow studies, the model reliably predicted the observed ANC time course following paclitaxel plus carboplatin observed in a phase 1 trial of 46 patients (r =0.70). The circulatory neutrophil model may provide a mechanistic framework for predicting multi-organ neutrophil homeostasis and dynamics in response to therapeutic agents that target neutrophil dynamics and trafficking in different organs.
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http://dx.doi.org/10.1002/psp4.12620DOI Listing
April 2021

Efficient catalytic conversion of microalgae residue solid waste into lactic acid over a Fe-Sn-Beta catalyst.

Sci Total Environ 2021 Jun 27;771:144891. Epub 2021 Jan 27.

State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment of Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address:

Microalgae residue was efficiently converted into lactic acid with a high yield (33.9%) under mild reaction conditions (210 °C, 2 h) over a Fe-Sn-Beta catalyst. Under the action of homogeneous HO and distinct Lewis acid sites on the catalyst, the production of lactic acid from microalgae residue underwent three main reaction steps: hydrolysis, isomerization, and retro-aldol condensation. Results demonstrated that the lipid component had a strong inhibitory effect on the production of lactic acid due to the formation of aromatics, esters, and complex nitrogenous heterocyclic compounds, which covered or poisoned the Lewis acid sites of the catalyst. The protein component acted as a chemical buffer that enhanced the production of lactic acid by controlling the release of monosaccharides from the carbohydrate fraction of microalgae and maintaining the catalytic activity of the catalyst. Thus, microalgae residue demonstrated great promise for the production of value-added chemicals.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144891DOI Listing
June 2021

Conditioned medium of human bone marrow-derived stem cells promotes tendon-bone healing of the rotator cuff in a rat model.

Biomaterials 2021 Apr 11;271:120714. Epub 2021 Feb 11.

Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, China. Electronic address:

Rotator cuff repair is a common surgery in sports medicine. During the surgery, torn tendon was re-fixed onto the bony surface. The majority of patients gain good results. However, re-tear occurs in some patients. The reason under this phenomenon is that the normal tendon-bone enthesis cannot be reconstructed. In order to strengthen the tendon-bone healing and promote enthesis regeneration, numerous manners are tested, among which stem cell related therapies are preferred. Stem cells, due to the ability of multi-lineage differentiation, are widely used in regenerative medicine. However, safety and ethics concerns limit its clinical use. Recent studies found that it is the secretome of stem cells that is biologically effective. On ground of this, we, in the current study, collected the conditioned medium of human bone marrow-derived stem cells (hBMSC-CM) and tested whether this acellular method could promote tendon-bone healing in a rat model of rotator cuff repair. By using histological, radiological, and biomechanical methods, we found that hBMSC-CM promoted tendon-bone healing of the rat rotator cuff. Then, we noticed that hBMSC-CM exerted an impact on macrophage polarization both in vivo and in vitro by inhibiting M1 phenotype and promoting M2 phenotype. Further, we proved that the benefit of hBMSC-CM on tendon-bone healing was related to its regulation on macrophage. Finally, we proved that, hBMSC-CM influenced macrophage polarization, which was, at least partially, related to Smad2/3 signaling pathway. Based on the experiments above, we confirmed the benefit of hBMSC-CM on tendon-bone healing, which relied on its immune-regulative property. Considering the accessibility and safety of acellular hBMSC-CM, we believe it is a promising candidate clinically for tendon-bone healing.
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http://dx.doi.org/10.1016/j.biomaterials.2021.120714DOI Listing
April 2021

Bench-to-bedside translation of chimeric antigen receptor (CAR) T cells using a multiscale systems pharmacokinetic-pharmacodynamic model: A case study with anti-BCMA CAR-T.

CPT Pharmacometrics Syst Pharmacol 2021 Apr 24;10(4):362-376. Epub 2021 Mar 24.

Discovery and Translational Research, Biologics Development Sciences, Janssen Biotherapeutics, Spring House, Pennsylvania, USA.

Despite tremendous success of chimeric antigen receptor (CAR) T cell therapy in clinical oncology, the dose-exposure-response relationship of CAR-T cells in patients is poorly understood. Moreover, the key drug-specific and system-specific determinants leading to favorable clinical outcomes are also unknown. Here we have developed a multiscale mechanistic pharmacokinetic (PK)-pharmacodynamic (PD) model for anti-B-cell maturation antigen (BCMA) CAR-T cell therapy (bb2121) to characterize (i) in vitro target cell killing in multiple BCMA expressing tumor cell lines at varying effector to target cell ratios, (ii) preclinical in vivo tumor growth inhibition and blood CAR-T cell expansion in xenograft mice, and (iii) clinical PK and PD biomarkers in patients with multiple myeloma. Our translational PK-PD relationship was able to effectively describe the commonly observed multiphasic CAR-T cell PK profile in the clinic, consisting of the rapid distribution, expansion, contraction, and persistent phases, and accounted for the categorical individual responses in multiple myeloma to effectively calculate progression-free survival rates. Preclinical and clinical data analysis revealed comparable parameter estimates pertaining to CAR-T cell functionality and suggested that patient baseline tumor burden could be more sensitive than dose levels toward overall extent of exposure after CAR-T cell infusion. Virtual patient simulations also suggested a very steep dose-exposure-response relationship with CAR-T cell therapy and indicated the presence of a "threshold" dose, beyond which a flat dose-response curve could be observed. Our simulations were concordant with multiple clinical observations discussed in this article. Moving forward, this framework could be leveraged a priori to explore multiple infusions and support the preclinical/clinical development of future CAR-T cell therapies.
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http://dx.doi.org/10.1002/psp4.12598DOI Listing
April 2021

LF1 regulates the lateral organs polarity development in rice.

New Phytol 2021 Jan 20. Epub 2021 Jan 20.

Key Laboratory of Application and Safety Control of Genetically Modified Crops, Rice Research Institute, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, China.

The patterning of adaxial-abaxial tissues plays a vital role in the morphology of lateral organs, which is maintained by antagonism between the genes that specify adaxial and abaxial tissue identity. The homeo-domain leucine zipper class III (HD-ZIP III) family genes regulate adaxial identity; however, little information is known about the physical interactions or transcriptionally regulated downstream genes of HD-ZIP III. In this study, we identified a dominant rice mutant, lateral floret 1 (lf1), which has defects in lateral organ polarity. LF1 encodes the HD-ZIP III transcription factor, which expressed in the adaxial area of lateral organs. LF1 can activate directly the expression of LITTLE ZIPPER family gene OsZPR4 and HD-ZIP II family gene OsHOX1, and OsZPR4 and OsHOX1 respectively interact with LF1 to form a heterodimer to repress the transcriptional activity of LF1. LF1 influences indole-3-acetic acid (IAA) content by directly regulating the expression of OsYUCCA6. Therefore, LF1 forms negative feedback loops between OsZPR4 and OsHOX1 to affect IAA content, leading to the regulation of lateral organs polarity development. These results reveal the cross-talk among HD-ZIP III, LITTLE ZIPPER, and HD-ZIP II proteins and provide new insights into the molecular mechanisms underlying the polarity development of lateral organs.
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http://dx.doi.org/10.1111/nph.17220DOI Listing
January 2021

Analysis of Apoptosis-Related Genes Reveals that Apoptosis Functions in Conidiation and Pathogenesis of .

mSphere 2021 01 6;6(1). Epub 2021 Jan 6.

College of Plant Protection, Henan Agricultural University, Zhengzhou, China

Apoptosis, a type of programmed cell death, plays crucial roles in various physiological processes, from development to adaptive responses. Key features of apoptosis have been verified in various fungal microbes but not yet in species. Here, we identified 19 apoptosis-related genes in using a genome-wide survey. Expression profile analysis revealed that several apoptosis-related genes were significantly increased during conidiation and infection stages. Among these is FpBIR1, with two BIR (baculovirus inhibitor-of-apoptosis protein repeat) domains at the N-terminal end of the protein, a homolog of BIR1, which is a unique apoptosis inhibitor. FpNUC1 is the ortholog of NUC1, which triggers AIF1- or YCA1-independent apoptosis. The functions of these two proteins were assessed by creating Δ and Δ mutants via targeted gene deletion. The Δ mutant had more cells with nuclear fragmentation and exhibited reduced conidiation, conidial formation, and infectivity. Correspondingly, the Δ mutant contained multiple nuclei, produced thicker and more branched hyphae, was reduced in conidiation, and exhibited faster conidial formation and higher infection rates. Taken together, our results indicate that the apoptosis-related genes and function in conidiation, conidial germination, and infection by The plant-pathogenic fungus is the causal agent of crown rot (FCR) in wheat and barley, resulting in substantial yield losses worldwide. Particularly, in the Huanghuai wheat-growing region of China, was reported as the dominant species in FCR infections. Apoptosis is an evolutionarily conserved mechanism in eukaryotes, playing crucial roles in development and cell responses to biotic and abiotic stresses. However, few reports on apoptosis in plant fungal pathogens have been published. In this study, we identified 19 conserved apoptosis-related genes in , several of which were significantly increased during conidiation and infection stages. Potential apoptosis functions were assessed by deletion of the putative apoptosis inhibitor gene and apoptosis trigger gene in The deletion mutant exhibited defects in conidial germination and pathogenicity, whereas the deletion mutant experienced faster conidial formation and higher infection rates. Apoptosis appears to negatively regulate the conidial germination and pathogenicity of To our knowledge, this study is the first report of apoptosis contributing to infection-related morphogenesis and pathogenesis in .
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http://dx.doi.org/10.1128/mSphere.01140-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7845595PMC
January 2021

Iterative Learning Control With Data-Driven-Based Compensation.

IEEE Trans Cybern 2021 Jan 5;PP. Epub 2021 Jan 5.

The robust iterative learning control (RILC) can deal with the systems with unknown time-varying uncertainty to track a repeated reference signal. However, the existing robust designs consider all the possibilities of uncertainty, which makes the design conservative and causes the controlled process converging to the reference trajectory slowly. To eliminate this weakness, a data-driven method is proposed. The new design intends to employ more information from the past input-output data to compensate for the robust control law and then to improve performance. The proposed control law is proved to guarantee convergence and accelerate the convergence rate. Ultimately, the experiments on a robot manipulator have been conducted to verify the good convergence of the trajectory errors under the control of the proposed method.
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http://dx.doi.org/10.1109/TCYB.2020.3041705DOI Listing
January 2021

Steroid Receptor Coactivator-3 Is Required for Inhibition of the Intestinal Muscularis Inflammatory Response of Postoperative Ileus in Mice.

Inflammation 2021 Jan 4. Epub 2021 Jan 4.

Department of Gastrointestinal Surgery, Ward 3 Areas of Cancer Center, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen University, Xiamen, 361003, China.

Inflammation theory has suggested that the pathogenesis of postoperative ileus (POI) involves the steroid receptor coactivator-3 (SRC-3). Therefore, we investigated the role of SRC-3 in the muscles of the small intestine using a mouse POI model. Here, we reported that intestinal manipulation (IM) significantly reduced the extent of phenol red migration in the entire gastrointestinal tract, and the calculated geometric center (GC) value in wild-type (WT) mice at 24 h after surgery was higher than that in the knockout (KO) mice and in the sham-operated control group. The expression of SRC-3 was upregulated in the mouse intestinal muscularis at 24 h after surgical manipulation, and the mRNA and protein levels of inflammatory cytokines were upregulated compared with those in the control group. At 24 h after IM, the number of neutrophils in the experimental group was significantly higher than that in the control group; in the IM group, the number of neutrophils in the SRC-3 mice was markedly higher than that in the WT mice. At 24 h after IM, the myeloperoxidase (MPO) activity in the experimental group was significantly higher than that in the control group. In the IM group, the MPO activity of the SRC-3 mice was markedly higher than that of the WT mice. In summary, proinflammatory cytokines, the number of neutrophils, and the MPO activity were significantly increased in the muscularis of the jejunum and ileum of KO mice after IM compared with those of the WT mice, indicating that SRC-3 might play a protective role in POI.
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http://dx.doi.org/10.1007/s10753-020-01409-4DOI Listing
January 2021

Deep-red photoluminescence from enhanced D-F transition in Eu doped CaGaGeO phosphors.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Mar 27;248:119247. Epub 2020 Nov 27.

Engineering Research Center of New Energy Storage Devices and Applications, Chongqing University of Arts and Sciences, Chongqing 402160, PR China. Electronic address:

In order to explore diverse luminescence properties of Eu in inorganic phosphors, a series of novel deep-red-emitting CaGaGeO phosphors were successfully synthesized by solid-state reactions. The phase formation was verified by the X-ray diffraction patterns and Rietveld refinement and there is only one kind of Ca site in CaGaGeO. The excitation spectrum shows typical excitation peaks of Eu and the broad band ranging from 200 nm to 300 nm was composed of the charge transfer band of O-Eu and Ga-O transition band. The emission spectrum depicts that the intensity of the peak located at 704 nm (D → F) is higher than that of 618 nm (D → F), which finally leads to the deep-red emission of the phosphor with high color saturation. The coordination dodecahedron of EuO8 distorted from a cubic geometry to the square antiprism is responsible for the unusual emission of Eu. The research of the concentration quenching behavior, lifetime and luminescence decay curves imply that the energy transfer between Eu ions finally leads to the concentration quenching, and the interaction type is d-d interaction. The charge compensation, quantum efficiency and the thermal stability of CaGaGeO:Eu were also studied.
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http://dx.doi.org/10.1016/j.saa.2020.119247DOI Listing
March 2021

Predicting Chemotherapy-Induced Neutropenia and Granulocyte Colony-Stimulating Factor Response Using Model-Based In Vitro to Clinical Translation.

AAPS J 2020 11 6;22(6):143. Epub 2020 Nov 6.

Department of Biomedical Engineering, University of Southern California, Los Angeles, California, 90089, USA.

The ability to predict the incidence of chemotherapy-induced neutropenia in early drug development can inform risk monitoring and mitigation strategies, as well as decisions on advancing compounds to clinical trials. In this report, a physiological model of granulopoiesis that incorporates the drug's mechanism of action on cell cycle proliferation of bone marrow progenitor cells was extended to include the action of the cytotoxic agents paclitaxel, carboplatin, doxorubicin, and gemcitabine. In vitro bone marrow studies were conducted with each compound, and results were used to determine the model's drug effect parameters. Population simulations were performed to predict the absolute neutrophil count (ANC) and incidence of neutropenia for each compound, which were compared to results reported in the literature. In addition, using the single agent in vitro study results, the model was able to predict ANC time course in response to paclitaxel plus carboplatin in combination, which compared favorably to the results reported in a phase 1 clinical trial of 46 patients (r = 0.70). Model simulations were used to compare the relative risk (RR) of neutropenia in patients with high baseline ANCs for five chemotherapeutic regimens: doxorubicin (RR = 0.59), paclitaxel plus carboplatin combination (RR = 0.079), carboplatin (RR = 0.047), paclitaxel (RR = 0.031), and gemcitabine (RR = 0.013). Finally, the model was applied to quantify the reduced incidence of neutropenia with coadministration of pegfilgrastim or filgrastim, for both paclitaxel and the combination of paclitaxel plus carboplatin. The model provides a framework for predicting clinical neutropenia using in vitro bone marrow studies of anticancer agents that may guide drug development decisions.
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http://dx.doi.org/10.1208/s12248-020-00529-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764847PMC
November 2020

Biokinetic modeling of nanoparticle interactions with lung alveolar epithelial cells: uptake, intracellular processing, and egress.

Am J Physiol Regul Integr Comp Physiol 2021 01 21;320(1):R36-R43. Epub 2020 Oct 21.

Will Rogers Institute Pulmonary Research Center and Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California, Los Angeles, California.

Studies on health effects of engineered nanomaterials (ENMs) in the lung have provided information on ENM toxicity and translocation across airway and alveolar epithelial barriers. Various inhaled ENMs (e.g., gold and iridium nanoparticles) have been reported to partially cross the air-blood barrier in the lung, enter the vasculature, and distribute in several end organs, including the heart, liver, spleen, and kidney. Using an in vitro primary rat alveolar epithelial cell (AEC) monolayer model, we reported transport rates of relatively nontoxic polystyrene nanoparticles (PNPs), which appear to be taken up via nonendocytic processes into AECs. PNPs internalized into cytoplasm then trigger autophagy, followed by delivery of PNPs from autophagosomes into lysosomes, from where PNPs are exocytosed. We used the data from these experiments to perform biokinetic modeling that incorporates the processes associated with internalization and intracellular distribution of PNPs, autophagy, lysosomal exocytosis of PNPs, and several putative mechanisms of action that extend our previous understanding of AEC processing of PNPs. Results suggest that entry of PNPs into AECs, subsequent activation of autophagy by cytosolic PNPs, accumulation of PNPs in lysosomes, and lysosomal exocytosis are interwoven by proposed regulatory mechanisms.
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http://dx.doi.org/10.1152/ajpregu.00184.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7847057PMC
January 2021

Model-Based Cellular Kinetic Analysis of Chimeric Antigen Receptor-T Cells in Humans.

Clin Pharmacol Ther 2021 Mar 13;109(3):716-727. Epub 2020 Oct 13.

Division of Pharmacotherapy and Experimental Therapeutics, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

Chimeric antigen receptor (CAR)-T cell therapy has achieved considerable success in treating B-cell hematologic malignancies. However, the challenges of extending CAR-T therapy to other tumor types, particularly solid tumors, remain appreciable. There are substantial variabilities in CAR-T cellular kinetics across CAR-designs, CAR-T products, dosing regimens, patient responses, disease types, tumor burdens, and lymphodepletion conditions. As a "living drug," CAR-T cellular kinetics typically exhibit four distinct phases: distribution, expansion, contraction, and persistence. The cellular kinetics of CAR-T may correlate with patient responses, but which factors determine CAR-T cellular kinetics remain poorly defined. Herein, we developed a cellular kinetic model to retrospectively characterize CAR-T kinetics in 217 patients from 7 trials and compared CAR-T kinetics across response status, patient populations, and tumor types. Based on our analysis results, CAR-T cells exhibited a significantly higher cell proliferation rate and capacity but a lower contraction rate in patients who responded to treatment. CAR-T cells proliferate to a higher degree in hematologic malignancies than in solid tumors. Within the assessed dose ranges (10 -10 cells), CAR-T doses were weakly correlated with CAR-T cellular kinetics and patient response status. In conclusion, the developed CAR-T cellular kinetic model adequately characterized the multiphasic CAR-T cellular kinetics and supported systematic evaluations of the potential influencing factors, which can have significant implications for the development of more effective CAR-T therapies.
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http://dx.doi.org/10.1002/cpt.2040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959329PMC
March 2021

No Differences in Clinical Outcomes of Suture Tape Augmented Repair Versus Broström Repair Surgery for Chronic Lateral Ankle Instability.

Orthop J Sports Med 2020 Sep 15;8(9):2325967120948491. Epub 2020 Sep 15.

Department of Sports Medicine, Huashan Hospital, Shanghai, People's Republic of China.

Background: Suture tape (ST) augmented repair, an alternative to traditional Broström repair (BR), may protect the repaired anterior talofibular ligament during ligament healing. No systematic review of cohort studies has been conducted to compare traditional BR with ST-augmented repair for chronic lateral ankle instability.

Purpose: To review the current evidence in the literature to ascertain whether ST-augmented repair is superior to traditional BR in managing chronic lateral ankle instability.

Study Design: Systematic review; Level of evidence, 3.

Methods: A literature search was performed to identify relevant articles published in PubMed, Embase, and Cochrane Library databases in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The search included cohort studies comparing the efficacy of BR and ST-augmented repair procedures in terms of incidence of instability recurrence, functional scores, talar tilt angle (TTA), anterior talar translation (ATT), and complication rate. Methodological quality was assessed using the Jadad scale for randomized studies and the Newcastle-Ottawa Scale for nonrandomized studies.

Results: A total of 4 clinical trials with 254 patients were included. No significant differences were detected between BR and ST-augmented repair procedures in terms of incidence of recurrent instability, American Orthopaedic Foot & Ankle Society score, Foot and Ankle Outcome Score, Foot and Ankle Ability Measure, TTA, ATT, or complication rate. The ST group appeared to have a shorter operation time compared with the BR group.

Conclusion: No significant differences were found between ST-augmented repair and BR surgery regarding incidence of recurrent instability, functional outcome scores, or complication rates. Although technically challenging, the ST-augmented repair procedure appears to be a safe and fast option.
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http://dx.doi.org/10.1177/2325967120948491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7495671PMC
September 2020

Deep Sequencing of Small RNAs in the Whitefly Reveals Novel MicroRNAs Potentially Associated with Begomovirus Acquisition and Transmission.

Insects 2020 Aug 23;11(9). Epub 2020 Aug 23.

USDA, Agricultural Research Service, U.S. Vegetable Laboratory, 2700 Savannah Hwy, Charleston, SC 29414, USA.

The whitefly (Gennadius) is a notorious insect vector that transmits hundreds of plant viruses, affecting food and fiber crops worldwide, and results in the equivalent of billions of U.S. dollars in crop loss annually. To gain a better understanding of the mechanism in virus transmission, we conducted deep sequencing of small RNAs on the whitefly MEAM1 (Middle East-Asia Minor 1) that fed on tomato plants infected with tomato yellow leaf curl virus (TYLCV). Overall, 160 miRNAs were identified, 66 of which were conserved and 94 were -specific. Among the -specific miRNAs, 67 were newly described in the present study. Two miRNAs, with predicted targets encoding a nuclear receptor () and a very-long-chain (3R)-3-hydroxyacyl-CoA dehydratase 2 (), respectively, were differentially expressed in whiteflies that fed on TYLCV-infected versus uninfected plants. To better understand the regulatory effects of identified miRNAs and their target genes, we correlated expression profiles of miRNAs and their target transcripts and found that, interestingly, miRNA expression was inversely correlated with the expression of ~50% of the predicted target genes. These analyses could serve as a model to study gene regulation in other systems involving arthropod transmission of viruses to plants and animals.
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http://dx.doi.org/10.3390/insects11090562DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564577PMC
August 2020

CircRNA inhibits DNA damage repair by interacting with host gene.

Mol Cancer 2020 08 24;19(1):128. Epub 2020 Aug 24.

School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China.

Background: Deregulated circular RNAs (circRNAs) are associated with the development of cancer and therapy resistance. However, functional research of circRNAs mostly focus on potential miRNA or protein binding and more potential regulation of circRNA on host gene DNA in cancers are yet to be inspected.

Method: We performed total RNA sequencing on clinical breast cancer samples and identified the expression patterns of circRNAs and corresponding host genes in patient blood, tumor and adjacent normal tissues. qPCR, northern blot and in situ hybridization were used to validate the dysregulation of circRNA circSMARCA5. A series of procedures including R-loop dot-blotting, DNA-RNA immunoprecipitation and mass spectrum, etc. were conducted to explore the regulation of circSMARCA5 on the transcription of exon 15 of SMARCA5. Moreover, immunofluorescence and in vivo experiments were executed to investigate the overexpression of circSMARCA5 with drug sensitivities.

Results: We found that circRNAs has average higher expression over its host linear genes in peripheral blood. Compared to adjacent normal tissues, circSMARCA5 is decreased in breast cancer tissues, contrary to host gene SMARCA5. The enforced expression of circSMARCA5 induced drug sensitivity of breast cancer cell lines in vitro and in vivo. Furthermore, we demonstrated that circSMARCA5 can bind to its parent gene locus, forming an R-loop, which results in transcriptional pausing at exon 15 of SMARCA5. CircSMARCA5 expression resulted in the downregulation of SMARCA5 and the production of a truncated nonfunctional protein, and the overexpression of circSMARCA5 was sufficient to improve sensitivity to cytotoxic drugs.

Conclusion: Our results revealed a new regulatory mechanism for circRNA on its host gene and provided evidence that circSMARCA5 may serve as a therapeutic target for drug-resistant breast cancer patients.
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http://dx.doi.org/10.1186/s12943-020-01246-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446195PMC
August 2020

Structural characterization of polysaccharides with potential antioxidant and immunomodulatory activities from Chinese water chestnut peels.

Carbohydr Polym 2020 Oct 15;246:116551. Epub 2020 Jun 15.

College of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China. Electronic address:

Chinese water chestnut peels are a kind of vegetable processing waste containing many active components such as polysaccharides, the structure of which remains unknown. To elucidate the structure of polysaccharides from Chinese water chestnut peels, two polysaccharides named WVP-1 and WVP-2 were isolated. WVP-1 (3.16 kDa) consisted of mannose (1.75 %), glucose (84.69 %), galactose (6.32 %), and arabinose (7.24 %), while WVP-2 (56.97 kDa) was composed of mannose (3.18 %), rhamnose (1.52 %), glucuronic acid (1.42 %), galacturonic acid (4.83 %), glucose (11.51 %), galactose (36.02 %), and arabinose (41.53 %). Linkage and NMR data indicated that WVP-1 was composed mainly of →4)-α-d-Glcp(1→ and a certain proportion of →3)-β-d-Glcp-(1→, including linear and branched polysaccharides simultaneously. WVP-2 was a pectin-like polysaccharide with →4)-α-d-GalpA6Me-(1→ units and the branch points of →3,4)-α-l-Arap-(1→, →3,6)-β-d-Galp-(1→. WVP-2 exhibited stronger potential antioxidant and immunomodulatory activities than WVP-1 in vitro. These results provide a foundation for the further study of polysaccharides from Chinese water chestnut peels.
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http://dx.doi.org/10.1016/j.carbpol.2020.116551DOI Listing
October 2020

Subnanometer-resolution structure determination in situ by hybrid subtomogram averaging - single particle cryo-EM.

Nat Commun 2020 07 24;11(1):3709. Epub 2020 Jul 24.

Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany.

Cryo-electron tomography combined with subtomogram averaging (StA) has yielded high-resolution structures of macromolecules in their native context. However, high-resolution StA is not commonplace due to beam-induced sample drift, images with poor signal-to-noise ratios (SNR), challenges in CTF correction, and limited particle number. Here we address these issues by collecting tilt series with a higher electron dose at the zero-degree tilt. Particles of interest are then located within reconstructed tomograms, processed by conventional StA, and then re-extracted from the high-dose images in 2D. Single particle analysis tools are then applied to refine the 2D particle alignment and generate a reconstruction. Use of our hybrid StA (hStA) workflow improved the resolution for tobacco mosaic virus from 7.2 to 4.4 Å and for the ion channel RyR1 in crowded native membranes from 12.9 to 9.1 Å. These resolution gains make hStA a promising approach for other StA projects aimed at achieving subnanometer resolution.
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http://dx.doi.org/10.1038/s41467-020-17466-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7381653PMC
July 2020

MicroRNA-188 inhibits biological activity of lung cancer stem cells through targeting MDK and mediating the Hippo pathway.

Exp Physiol 2020 08 8;105(8):1360-1372. Epub 2020 Jul 8.

Department of Oncological Gynecology, The First Hospital of Jilin University, Changchun, Jilin, 130021, PR China.

New Findings: What is the central question of this study? The aim was to investigate the function of microRNA-188 in the biological characteristics of lung cancer stem cells and the molecular mechanisms involved. What is the main finding and its importance? This study highlights a new molecular mechanism involving microRNA-188, MDK and the Hippo signalling pathway that plays a suppressive role in biological activity of lung cancer stem cells. This finding might offer new insights into gene-based therapy for lung cancer.

Abstract: MicroRNAs (miRNAs) have been implicated in lung cancer and reported as new promising diagnostic and therapeutic tools for cancer control. Here, we investigated the action of microRNA-188 (miR-188) in lung cancer stem cells. We first tested miR-188 expression in clinical samples of lung cancer patients, and a low expression profile of miR-188 was found. Next, we analysed the role of miR-188 in lung cancer stem cells with cell growth assays. To verify the in vitro results, we used a xenograft model to validate the capability of miR-188 in tumorigenesis. Overexpression of miR-188 reduced viability and metastasis of cancer stem cells. Similar results were reproduced in vivo, where overexpression of miR-188 retarded tumour growth in mice. We also identified MDK as a target of miR-188, and overexpression of MDK was found in lung cancer samples. Overexpressed MDK promoted the malignant behaviours of lung cancer stem cells. In addition, the Hippo pathway was found to be inactivated in lung cancer tissues, presenting as increased levels of YAP and TAZ. Suppression of the Hippo pathway also enhanced lung cancer stem cell activity and promoted the growth of xenograft tumours. To sum up, our results reveal that miR-188 inhibits the malignant behaviours of lung cancer stem cells and the growth of xenograft tumours. This study might offer new insights into gene-based therapies for cancer.
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http://dx.doi.org/10.1113/EP088704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496401PMC
August 2020

Temperature/pH Smart Nanofibers with Excellent Biocompatibility and Their Dual Interactions Stimulus-Responsive Mechanism.

J Agric Food Chem 2020 Jul 4;68(28):7425-7433. Epub 2020 Jul 4.

School of Light Industry and Food Engineering, Guangxi University, Nanning 530004, P.R. China.

Novel nanosized biomass-based pH- and temperature-responsive cellulose nanofibers (TOCNF-HPEI-IBAm) were designed and prepared by grafting hyperbranched polyethylenimine (HPEI) modified with isobutyramide (IBAm) groups (HPEI-IBAm) onto carboxylated cellulose nanofibers (TOCNFs). The as-prepared TOCNF-HPEI-IBAm possessed excellent biocompatibility and pH- and temperature-responsive properties. TOCNF-HPEI-IBAm showed a rapid wettability conversion from hydrophilic (WCA = 41.1°, WCA = 70.7°) to hydrophobic (WCA = 147.3°, WCA = 142.2°) in response to changes in pH and temperature from acidic conditions to alkaline conditions and from lower to higher temperatures. In addition, it possesses strong antibacterial activity against and (Eb ≥ 97%). The amount of DOX loaded in TOCNF-HPEI-IBAm was 642.52 mg/g, and the maximum amount of DOX released was 39.30% at pH = 3.0 within 9 h. Furthermore, the dual interactions stimulus-responsive mechanism was revealed to be attributed to the expansion and collapse of the molecular chains of TOCNF-HPEI-IBAm in response to temperature and pH through mutual promotion and inhibition.
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http://dx.doi.org/10.1021/acs.jafc.0c01493DOI Listing
July 2020

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6.

Rice (N Y) 2020 Jun 11;13(1):40. Epub 2020 Jun 11.

Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, China.

Background: Grain size affects not only rice yield but is also an important element in quality of appearance. However, the mechanism for inheritance of grain size is unclear.

Results: A rice chromosome segment substitution line Z1392, which harbors three substitution segments and produces grains of increased length, was identified. The three chromosome segments were located on chromosomes 1, 5, and 6, and the average length of the substitution segment was 3.17 Mb. Cytological analysis indicates that the predominant cause of increased grain length in Z1392 could be cell expansion in the glumes. Seven quantitative trait loci (QTLs) for grain size related traits were identified using the secondary F population produced by Nipponbare/Z1392. The inheritance of grain length in Z1392 was mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was localized on a 1.26 Mb region on chromosome 6, and OsARF19 may be its candidate gene. Based on QTL mapping, three single-segment substitution lines (S1, S2, and S3) and two double-segment substitution lines (D1 and D2) were selected, and the mapping accuracy for qGL-5 and qGL-6 was further verified using three single-segment substitution lines. Analysis of QTL additive and epistatic effects revealed that the additive effect of alleles qGL-5 and qGL-6 from 'Xihui 18' was estimated to increase grain length of Z1392 by 0.22 and 0.15 mm, respectively. In addition, a positive epistatic interaction between qGL-5 and qGL-6 was detected, which indicates that the pyramiding of qGL-5 and qGL-6 for grain length produces a novel genotype with longer grains.

Conclusions: Inheritance of grain length in the triple-segment substitution line Z1392 is mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was found to be located in a 1.26 Mb region on chromosome 6, and OsARF19 may be its candidate gene. A positive epistatic interaction between qGL-5 and qGL-6 results in longer grains. The present results can be used to facilitate cloning of the qGL-5 and qGL-6 genes and contribute to improvement of grain yield in rice.
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http://dx.doi.org/10.1186/s12284-020-00399-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290020PMC
June 2020

Synthesis and luminescence properties of a novel deep red phosphor LiZnTiO:Mn for plant-cultivation.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Oct 1;240:118567. Epub 2020 Jun 1.

School of Physics and Opto-Electronic Technology, Collaborative Innovation Center of Rare-Earth Optical Functional Materials and Devices Development, Baoji University of Arts and Sciences, Baoji, Shaanxi 721016, PR China; School of Management, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address:

In this thesis, a novel ultraviolet-activated LiZnTiO:Mn red emitting phosphor is prepared by the traditional high-temperature solid-state reaction method in air. The crystal structure, luminescence properties and decay curves of the phosphor are studied in detail. The sample belongs to spinel cubic crystal structure and there are abundant [TiO] octahedron sites can be occupied by Mn. The LiZnTiO:Mn phosphor shows the red emission in region of 600-800 nm with a maximum at ~681 nm under 330 nm excitation, which can promote the plant growth. The optimal Mn doping concentration is ~0.3 mol%, which is higher than that of other hosts. By calculating the crystal field strength (Dq) and Racah parameter B, we can evaluate that there is a strong crystal environment of Mn in the LiZnTiO host lattice, which major comes from the E → A transition of Mn ion. Furthermore, the characteristics of thermal quenching are also studied, poor thermal quenching performance may be due to high doping concentration of Mn. All data suggest that LiZnTiO:Mn phosphor can be a potential application in plant-cultivation.
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http://dx.doi.org/10.1016/j.saa.2020.118567DOI Listing
October 2020

KASP Genotyping as a Molecular Tool for Diagnosis of Cassava-Colonizing .

Insects 2020 May 14;11(5). Epub 2020 May 14.

International Institute of Tropical Agriculture, P.O. Box 34441 Dar es Salaa, Tanzania.

is a cryptic species complex that requires the use of molecular tools for identification. The most widely used approach for achieving this is the partial sequencing of the mitochondrial DNA cytochrome oxidase I gene (). A more reliable single nucleotide polymorphism (SNP)-based genotyping approach, using Nextera restriction-site-associated DNA (NextRAD) sequencing, has demonstrated the existence of six major haplogroups of on cassava in Africa. However, NextRAD sequencing is costly and time-consuming. We, therefore, developed a cheaper and more rapid diagnostic using the Kompetitive Allele-Specific PCR (KASP) approach. Seven sets of primers were designed to distinguish the six haplogroups based on the NextRAD data. Out of the 152 whitefly samples that were tested using these primer sets, 151 (99.3%) produced genotyping results consistent with NextRAD. The KASP assay was designed using NextRAD data on whiteflies from cassava in 18 countries across sub-Saharan Africa. This assay can, therefore, be routinely used to rapidly diagnose cassava by laboratories that are researching or monitoring this pest in Africa. This is the first study to develop an SNP-based assay to distinguish whiteflies on cassava in Africa, and the first application of the KASP technique for insect identification.
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http://dx.doi.org/10.3390/insects11050305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290743PMC
May 2020

Genome analysis of plant growth-promoting rhizobacterium Pseudomonas chlororaphis subsp. aurantiaca JD37 and insights from comparasion of genomics with three Pseudomonas strains.

Microbiol Res 2020 Aug 1;237:126483. Epub 2020 May 1.

Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China. Electronic address:

Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant growth promotion, rhizosphere colonization and biocontrol activities. In present study, the genome sequence of JD37 was obtained and comparative genomic analysis were performed to explore unique features of the JD37 genome and its relationship with other Pseudomonas PGPR: P. chlororaphis PA23, P. protegens Pf-5 and P. aeruginosa M18. JD37 possessed a single circular chromosome of 6,702,062 bp in length with an average GC content of 62.75 %. No plasmid was detected in JD37. A total of 5003 functional proteins of JD37 were predicted according to the clusters of orthologous groups (COGs) database. The JD37 genome consisted of various genes involved in plant growth promotion, biocontrol activities and defense responses. Genes involved in the rhizosphere colonization and motility were also found in the genome of JD37, suggesting the common plant growth-promoting traits in PGPR. The identified resistance genes (e.g. those related to metal resistance, antibiotics, and osmotic and temperature-shock) and secondary metabolite biosynthesis revealed the pathways for metabolites it produced. Data presented in present study further provided valuable information on its molecular genetics and adaptive capacity in the rhizosphere niche.
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http://dx.doi.org/10.1016/j.micres.2020.126483DOI Listing
August 2020

Near-Complete Genome Sequence of a Fish Nervous Necrosis Virus Isolated from Hybrid Grouper in China.

Microbiol Resour Announc 2020 Apr 9;9(15). Epub 2020 Apr 9.

School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China

The genome sequence of nervous necrosis virus strain HGN1910, isolated from hybrid grouper (♀ × ♂), was cloned, sequenced, and characterized. Two near-complete gene segments were obtained, RNA1 and RNA2. Phylogenetic analysis shows that the virus belongs to the red-spotted grouper nervous necrosis virus genotype of betanodavirus.
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http://dx.doi.org/10.1128/MRA.01453-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7380520PMC
April 2020

Cryo-EM structures of S-OPA1 reveal its interactions with membrane and changes upon nucleotide binding.

Elife 2020 03 31;9. Epub 2020 Mar 31.

National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.

Mammalian mitochondrial inner membrane fusion is mediated by optic atrophy 1 (OPA1). Under physiological conditions, OPA1 undergoes proteolytic processing to form a membrane-anchored long isoform (L-OPA1) and a soluble short isoform (S-OPA1). A combination of L-OPA1 and S-OPA1 is essential for efficient membrane fusion; however, the relevant mechanism is not well understood. In this study, we investigate the cryo-electron microscopic structures of S-OPA1-coated liposomes in nucleotide-free and GTPγS-bound states. S-OPA1 exhibits a general dynamin-like structure and can assemble onto membranes in a helical array with a dimer building block. We reveal that hydrophobic residues in its extended membrane-binding domain are critical for its tubulation activity. The binding of GTPγS triggers a conformational change and results in a rearrangement of the helical lattice and tube expansion similar to that of S-Mgm1. These observations indicate that S-OPA1 adopts a dynamin-like power stroke membrane remodeling mechanism during mitochondrial inner membrane fusion.
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http://dx.doi.org/10.7554/eLife.50294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156267PMC
March 2020

A physiological model of granulopoiesis to predict clinical drug induced neutropenia from in vitro bone marrow studies: with application to a cell cycle inhibitor.

J Pharmacokinet Pharmacodyn 2020 04 11;47(2):163-182. Epub 2020 Mar 11.

Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA.

Neutropenia is one of the most common dose-limiting toxocities associated with anticancer drug therapy. The ability to predict the probability and severity of neutropenia based on in vitro studies of drugs in early drug development will aid in advancing safe and efficacious compounds to human testing. Toward this end, a physiological model of granulopoiesis and its regulation is presented that includes the bone marrow progenitor cell cycle, allowing for a mechanistic representation of the action of relevant anticancer drugs based on in vitro studies. Model development used data from previously reported tracer kinetic studies of granulocyte disposition in healthy humans to characterize the dynamics of neutrophil margination in the presence of endogenous granulocyte-colony stimulating factor (G-CSF). In addition, previously published data from healthy volunteers following pegfilgrastim and filgrastim were used to quantify the regulatory effects of support G-CSF therapies on granulopoiesis. The model was evaluated for the cell cycle inhibitor palbociclib, using an in vitro system of human bone marrow mononuclear cells to quantify the action of palbociclib on proliferating progenitor cells, including its inhibitory effect on G1 to S phase transition. The in vitro results were incorporated into the physiological model of granulopoiesis and used to predict the time course of absolute neutrophil count (ANC) and the incidence of neutropenia observed in three previously reported clinical trials of palbociclib. The model was able to predict grade 3 and 4 neutropenia due to palbociclib treatment with 86% accuracy based on in vitro data.
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http://dx.doi.org/10.1007/s10928-020-09680-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211488PMC
April 2020

Structure of RyR1 in native membranes.

EMBO Rep 2020 05 9;21(5):e49891. Epub 2020 Mar 9.

Max Planck Institute for Biophysics, Frankfurt on Main, Germany.

Ryanodine receptor 1 (RyR1) mediates excitation-contraction coupling by releasing Ca from sarcoplasmic reticulum (SR) to the cytoplasm of skeletal muscle cells. RyR1 activation is regulated by several proteins from both the cytoplasm and lumen of the SR. Here, we report the structure of RyR1 from native SR membranes in closed and open states. Compared to the previously reported structures of purified RyR1, our structure reveals helix-like densities traversing the bilayer approximately 5 nm from the RyR1 transmembrane domain and sarcoplasmic extensions linking RyR1 to a putative calsequestrin network. We document the primary conformation of RyR1 in situ and its structural variations. The activation of RyR1 is associated with changes in membrane curvature and movement in the sarcoplasmic extensions. Our results provide structural insight into the mechanism of RyR1 in its native environment.
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http://dx.doi.org/10.15252/embr.201949891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202208PMC
May 2020

Inflammation-induced JMJD2D promotes colitis recovery and colon tumorigenesis by activating Hedgehog signaling.

Oncogene 2020 04 24;39(16):3336-3353. Epub 2020 Feb 24.

State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China.

Histone demethylase JMJD2D can promote gene expression by specifically demethylating H3K9me2/3. The role of JMJD2D in colitis and colitis-associated colorectal cancer (CRC) progression remains unclear. Here, we show that colonic JMJD2D is induced by TNFα during dextran sulfate sodium-induced colitis. JMJD2D-deficient mice exhibit more severe colon damage and defective colon regeneration due to impaired Hedgehog signaling activation after colitis. JMJD2D knockdown in CRC cells suppresses Hedgehog signaling, resulting in reduced CRC growth and metastasis. Mechanistically, JMJD2D promotes Hedgehog target gene expression through interacting with Gli2 to reduce H3K9me3 levels at the promoter. Clinically, JMJD2D expression is upregulated and positively correlated with Gli2 expression in human inflammatory bowel disease specimens and CRC specimens. The JMJD2D inhibitor 5-c-8HQ or aspirin synergizes with Hedgehog inhibitor vismodegib to inhibit CRC cell proliferation and tumorigenesis. Collectively, our findings unveil an essential role of JMJD2D in activating the processes of colonic protection, regeneration, and tumorigenesis.
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http://dx.doi.org/10.1038/s41388-020-1219-2DOI Listing
April 2020

Engineering stable radicals using photochromic triggers.

Nat Commun 2020 02 18;11(1):945. Epub 2020 Feb 18.

State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, 200438, China.

Long-standing radical species have raised noteworthy concerns in organic functional chemistry and materials. However, there remains a substantial challenge to produce long-standing radicals by light, because of the structural dilemmas between photoproduction and stabilization. Herein, we present a pyrrole and chloride assisted photochromic structure to address this issue. In this well-selected system, production and stabilization of a radical species were simultaneously found accompanied by a photochemical process in chloroform. Theoretical study and mechanism construction indicate that the designed π-system provides a superior spin-delocalization effect and a large steric effect, mostly avoiding possible consumptions and making the radical stable for hours even under an oxygen-saturated condition. Moreover, this radical system can be applied for a visualized and quantitative detection towards peroxides, such as 2,2,6,6-tetramethylpiperidine-1-oxyl, hydrogen peroxide, and ozone. As the detection relies on a radical capturing mechanism, a higher sensing rate was achieved compared to traditional redox techniques for peroxide detection.
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http://dx.doi.org/10.1038/s41467-020-14798-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028928PMC
February 2020