Publications by authors named "Xiaohua He"

194 Publications

Pine Rosin as a Valuable Natural Resource in the Synthesis of Fungicide Candidates for Controlling on Cucumber.

J Agric Food Chem 2021 Jun 2;69(23):6475-6484. Epub 2021 Jun 2.

Department of Chemistry and Biochemistry, University of Michigan-Flint, Flint, Michigan 48502, United States.

To improve the effect of pine rosin in plant fungicides, four series of dehydroabietyl-1,3,4-thiadiazole derivatives from the natural product rosin were synthesized. Based on the evaluation of the antifungal activity against , , , and , rosin-based 1,3,4-thiadiazole compounds containing thiophene heterocycles were screened. Notably, compound [dehydroabietyl-(1,3,4-thiadiazol-2-yl)-5-nitrothiophene-2-carboxamide] exhibited excellent antifungal property against with an EC of 0.618 mg/L, which was lower than that of the positive control carbendazim (0.649 mg/L). The antifungal activity results showed that exerted a protective effect on cucumber plants. Physiological and biochemical studies showed that the primary mechanism of action of compound on was it changed the mycelial morphology, increased the cell membrane permeability, and inhibited the synthesis of ergosterol in the mycelia. Furthermore, the quantitative structure-activity relationship studies revealed that the frontier orbital energy in the molecule had a key role in the antifungal activity through the conjugation and electrostatic interaction between compound and the receptors of the target. Thus, the present study highlighted the application of rosin-based fungicidal candidates and exploited efficient plant pesticides for sustainable crop production.
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http://dx.doi.org/10.1021/acs.jafc.1c01887DOI Listing
June 2021

Prevalence and Genetic Analysis of Chromosomal in From U.S. Animal-Derived Samples.

Front Microbiol 2021 30;12:667406. Epub 2021 Apr 30.

Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States.

The prevalence of -positive bacteria in 5,169 domestic animal-derived samples collected by USDA Food Safety and Inspection Service between October 2018 and May 2019 was investigated. A procedure including enriched broth culture and real-time PCR targeting to were used for the screening. Fifteen positive isolates were identified, including one plasmid-borne -positive strain, EC2492 (reported elsewhere) and 14 -positive strains from poultry (1), catfish (2), and chicken rinse (11) samples, resulting in an overall prevalence of -positive bacteria 0.29% in all meat samples tested. Analysis of 16S rRNA and whole genome sequences revealed that all 14 strains belonged to . Data from phylogenetic analysis of seven housekeeping genes, including , and , indicated that nine strains belonged to and five strains belonged to . Antimicrobial tests showed that almost all -positive strains exhibited high resistance to colistin with MICs ≥ 128mg/L, except for one strain, which showed a borderline resistance with a MIC of 2 mg/L. A segment containing two adjacent and lik genes was found in two and one strains and a variety of IS-like elements were found in the flanking regions of this segment. A -related lipid A phosphoethanolamine transferase gene was present in all 14 strains, while an additional -related lipid A phosphoethanolamine transferase gene was found in 5 strains only. In addition to genes, other antimicrobial resistance genes, including , , , , , , , , and were observed in chromosomes of some strains. The relative high prevalence of chromosome-borne genes and the close proximity of various IS elements to these genes highlights the need for continued vigilance to reduce the mobility of these colistin-resistance genes among food animals.
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http://dx.doi.org/10.3389/fmicb.2021.667406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120114PMC
April 2021

Elevated expression of HMGB1 is prognostic of poor survival in patients with relapsed/refractory T/NK-CL.

Ann Hematol 2021 May 15. Epub 2021 May 15.

Department of Medical Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China.

Despite the clinical value of HMGB1 in non-Hodgkin lymphoma (NHL), the impact of HMGB1 protein expression on survival of patients with mature T-cell and NK-cell lymphoma (T/NK-CL) is unknown. Here, we evaluated correlations of HMGB1 expression in tumor tissues with pathophysiological characteristics of disease and determined the prognostic value of HMGB1 expression in relapsed/refractory T/NK-CL. HMGB1 expression was detected by immunohistochemistry (IHC) in 66 cases of relapsed/refractory T/NK-CL, and specimens were classified as high or low HMGB1 expression. Univariate and multivariate Cox regression analyses identified prognostic factors associated with progression-free survival (PFS) and overall survival (OS). High HMGB1 expression was significantly correlated with increased Ki67 levels and progressive lymphoma subtypes. Univariate Cox regression analysis showed that high HMGB1 expression was associated with unfavorable PFS (P = 0.006) and poorer OS (P < 0.001). Prognostic factors identified by univariate analysis were prognostic index for peripheral T-cell lymphoma non-specified (PIT) score ≥ 2, bone marrow involvement, Ki67 ≥ 70%, and high HMGB1 expression. Multivariate Cox regression analysis revealed that high HMGB1 expression was an independent prognostic factor for poorer PFS [hazard ratio (HR) 3.593; 95% confidence interval (CI) 1.171-11.027; P = 0.025] and OS [HR 7.663; 95% CI 2.367-24.803; P = 0.001]. A proposal prognostic model combining HMGB1 and Ki67 expression showed improved prognostic capacity and may help guide treatment planning. High HMGB1 expression may be a promising prognostic predictor and a potential therapeutic target for relapsed/refractory T/NK-CL. Furthermore, to apply HMGB1 as one of the best bio-maker, an external independent control cohort is needed.
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http://dx.doi.org/10.1007/s00277-021-04473-4DOI Listing
May 2021

The effect of dipeptidyl peptidase IV on disease-associated microglia phenotypic transformation in epilepsy.

J Neuroinflammation 2021 May 11;18(1):112. Epub 2021 May 11.

Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Donghu Road No. 185, Wuchang, Wuhan, 430071, China.

Background: Accumulating evidence suggests that disease-associated microglia (DAM), a recently discovered subset of microglia, plays a protective role in neurological diseases. Targeting DAM phenotypic transformation may provide new therapeutic options. However, the relationship between DAM and epilepsy remains unknown.

Methods: Analysis of public RNA-sequencing data revealed predisposing factors (such as dipeptidyl peptidase IV; DPP4) for epilepsy related to DAM conversion. Anti-epileptic effect was assessed by electroencephalogram recordings and immunohistochemistry in a kainic acid (KA)-induced mouse model of epilepsy. The phenotype, morphology and function of microglia were assessed by qPCR, western blotting and microscopic imaging.

Results: Our results demonstrated that DPP4 participated in DAM conversion and epilepsy. The treatment of sitagliptin (a DPP4 inhibitor) attenuated KA-induced epilepsy and promoted the expression of DAM markers (Itgax and Axl) in both mouse epilepsy model in vivo and microglial inflammatory model in vitro. With sitagliptin treatment, microglial cells did not display an inflammatory activation state (enlarged cell bodies). Furthermore, these microglia exhibited complicated intersections, longer processes and wider coverage of parenchyma. In addition, sitagliptin reduced the activation of NF-κB signaling pathway and inhibited the expression of iNOS, IL-1β, IL-6 and the proinflammatory DAM subset gene CD44.

Conclusion: The present results highlight that the DPP4 inhibitor sitagliptin can attenuate epilepsy and promote DAM phenotypic transformation. These DAM exhibit unique morphological features, greater migration ability and better surveillance capability. The possible underlying mechanism is that sitagliptin can reduce the activation of NF-κB signaling pathway and suppress the inflammatory response mediated by microglia. Thus, we propose DPP4 may act as an attractive direction for DAM research and a potential therapeutic target for epilepsy.
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http://dx.doi.org/10.1186/s12974-021-02133-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8114532PMC
May 2021

The Upregulation of a Novel Long Noncoding RNA AK097647 Promotes Enterovirus 71 Replication and Decreases IFN-λ1 Secretion.

Intervirology 2021 May 5:1-9. Epub 2021 May 5.

Shenzhen Institute of Wuhan University, Shenzhen, China.

Background: Enterovirus 71 (EV71) infects millions of children every year in China and has become a challenge to public health. However, there is no effective treatment for EV71 infection. Long noncoding RNAs (lncRNAs) have been found to play various roles in virus replication and infection.

Objective: We aimed to explore the role of a novel long noncoding RNA AK097647 (lncRNA-AK097647) during EV71 infection.

Methods: To assess the role of lncRNA-AK097647 during EV71 infection, siRNAs were used to silence lncRNA-K097647 expression. RT-qPCR assay and Western blotting were applied to measure the mRNA and protein levels of EV71 VP1 and the phosphorylation of NF-κB. ELISA was used to detect the level of IFN-λ1 expression.

Results: The novel lncRNA-AK097647 was upregulated in human rhabdomyosarcoma cells and the blood of hand, foot, and mouth disease patients infected with EV71, as demonstrated by RT-qPCR. Interestingly, RNAi-mediated knockdown of lncRNA-AK097647 dramatically increased the level of IFN-λ1 expression, resulting in the suppression of EV71 replication. In contrast, overexpression of lncRNA-AK097647 decreased the level of IFN-λ1 expression and resulted in increased EV71 replication. In addition, we found that lncRNA-AK097647 could inhibit the phosphorylation of NF-κB.

Conclusion: These results suggest a novel mechanism by which EV71 evades the IFN-mediated host antiviral response by increasing lncRNA-AK097647 expression.
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http://dx.doi.org/10.1159/000515903DOI Listing
May 2021

Human Leukemia T-Cell Lines as Alternatives to Animal Use for Detecting Biologically Active Staphylococcal Enterotoxin Type B.

Toxins (Basel) 2021 04 23;13(5). Epub 2021 Apr 23.

Foodborne Toxin Detection & Prevention Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA.

Staphylococcal enterotoxin type B (SEB) is associated with food poisoning. Current methods for the detection of biologically active SEB rely upon its ability to cause emesis when administered to live kittens or monkeys. This technique suffers from poor reproducibility and low sensitivity and is ethically disfavored over concerns for the welfare of laboratory animals. The data presented here show the first successful implementation of an alternative method to live animal testing that utilizes SEB super-antigenic activity to induce cytokine production for specific novel cell-based assays for quantifiable detection of active SEB. Rather than using or sacrificing live animals, we found that SEB can bind to the major histocompatibility complex (MHC) class II molecules on Raji B-cells. We presented this SEB-MHC class II complex to specific Vβ5.3 regions of the human T-cell line HPB-ALL, which led to a dose-dependent secretion of IL-2 that is capable of being quantified and can further detect 10 pg/mL of SEB. This new assay is 100,000 times more sensitive than the ex vivo murine splenocyte method that achieved a detection limit of 1 µg/mL. The data presented here also demonstrate that SEB induced proliferation in a dose-dependent manner for cells obtained by three different selection methods: by splenocyte cells containing 22% of CD4 T-cells, by CD4 T-cells enriched to >90% purity by negative selection methods, and by CD4 T-cells enriched to >95% purity by positive selection methods. The highly enriched and positively isolated CD4 T-cells with the lowest concentration of antigen-presenting cells (APC) (below 5%) provided higher cell proliferation than the splenocyte cells containing the highest concentration of APC cells.
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http://dx.doi.org/10.3390/toxins13050300DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145393PMC
April 2021

Comparison of the edible quality of liquid egg with different cooking methods and their antioxidant activity after in vitro digestion.

Food Res Int 2021 02 14;140:110013. Epub 2020 Dec 14.

College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address:

The purpose of this study was to compare the edible quality of liquid egg after steaming, baking, frying and microwaving. Texture profile analysis (TPA) and color analysis were used to evaluate the sensory characteristics of cooked eggs. The fat, vitamin A and E, protein and amino acid content of cooked eggs and the antioxidant activity after in vitro digestion were determined to display the variations in nutritional value. TPA results demonstrate that baked egg exhibited a softer and more elasticity texture, with a significant lower hardness of 3234 g than fried and microwaved eggs (p < 0.05). This is also consistent with the results of cohesiveness and chewiness. Consequences from scanning electron microscope showed plentiful honeycomb structure in baked egg, which may be related to the soft and elasticity texture. However, significantly higher contents of fat, vitamins A and E, protein were determined in fried egg (p < 0.05), which may be related to its lower moisture content. The strongest free radical scavenging efficiency for the hydroxyl, the DPPH and the superoxide radical were found in the gastrointestinal digestion of fried egg, with the rate of 95.76%, 81.08%, and 91.08%, respectively. Overall, baked egg showed superior soft and elasticity taste characteristics due to its honeycomb structure, while fried egg exhibited better antioxidant activity because of its high contents in vitamins and amino acids. The above results provide potential approach for the manufacture of pre-cooked eggs and related products using liquid eggs as ingredients.
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http://dx.doi.org/10.1016/j.foodres.2020.110013DOI Listing
February 2021

Identification of genetic determinants of hemolytic activity of Riemerella anatipestifer using random transposon mutagenesis.

Vet Res 2021 Feb 12;52(1):19. Epub 2021 Feb 12.

Shanghai Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai, 200241, China.

Riemerella anatipestifer causes epizootic infectious disease in poultry resulting in serious economic losses especially to the duck industry. In our previous study, R. anatipestifer was found to lyse duck erythrocytes in vitro. In the present study, a random Tn4351 mutagenesis library of hemolytic R. anatipestifer strain SX containing 4000 mutants was constructed to investigate the genetic basis of hemolytic activity. Thirty mutants with reduced hemolytic activity and one with increased hemolytic activity were screened and insertions in 24 genes were identified. Of these genes, four were predicted to encode outer membrane proteins, one encoded a cytoplasmic membrane protein, 11 encoded cytoplasmic proteins, and eight encoded proteins with unknown locations. Based on current annotations of the R. anatipestifer genomes, of the 24 genes, 7 (29.17%) were involved in iron utilization. The hemolytic activities of the complemented strains M2 (pRES-Riean_0790) and M18 (pRES-Riean_0653) were restored, indicating that both Riean_0653 and Riean_0790 are involved in the hemolytic activity of strain SX. However, the recombinant proteins rRiean_0317, rRiean_0790, rRiean_0653, rRiean_1027, rRiean_1143, and rRiean_1561 had no hemolytic activity, suggesting that none were hemolysins.
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http://dx.doi.org/10.1186/s13567-021-00900-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7881567PMC
February 2021

DNA adenine methylase, not the PstI restriction-modification system, regulates virulence gene expression in Shiga toxin-producing Escherichia coli.

Food Microbiol 2021 Jun 31;96:103722. Epub 2020 Dec 31.

Biosecurity and Public Health Group, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.

We previously reported a distinct methylome between the two Shiga toxin-producing Escherichia coli (STEC) O145:H28 strains linked to the 2010 U.S. lettuce-associated outbreak (RM13514) and the 2007 Belgium ice cream-associated outbreak (RM13516), respectively. This difference was thought to be attributed to a prophage encoded type II restriction-modification system (PstI R-M) in RM13514. Here, we characterized this PstI R-M system in comparison to DNA adenine methylase (Dam), a highly conserved enzyme in γ proteobacteria, by functional genomics. Deficiency in Dam led to a differential expression of over 1000 genes in RM13514, whereas deficiency in PstI R-M only impacted a few genes transcriptionally. Dam regulated genes involved in diverse functions, whereas PstI R-M regulated genes mostly encoding transporters and adhesins. Dam regulated a large number of genes located on prophages, pathogenicity islands, and plasmids, including Shiga toxin genes, type III secretion system (TTSS) genes, and enterohemolysin genes. Production of Stx2 in dam mutant was significantly higher than in RM13514, supporting a role of Dam in maintaining lysogeny of Stx2-prophage. However, following mitomycin C treatment, Stx2 in RM13514 was significantly higher than that of dam or PstI R-M deletion mutant, implying that both Dam and PstI R-M contributed to maximum Stx2 production.
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http://dx.doi.org/10.1016/j.fm.2020.103722DOI Listing
June 2021

Differential induction of Shiga toxin in environmental Escherichia coli O145:H28 strains carrying the same genotype as the outbreak strains.

Int J Food Microbiol 2021 Feb 23;339:109029. Epub 2020 Dec 23.

U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Foodborne Toxin and Detection Research Unit, Albany, CA, USA.

Shiga toxin-producing Escherichia coli (STEC) O145 is a major serotype associated with severe human disease. Production of Shiga toxins (Stxs), especially Stx2a, is thought to be correlated with STEC virulence. Since stx genes are located in prophages genomes, induction of prophages is required for effective Stxs production. Here, we investigated the production of Stxs in 12 environmental STEC O145:H28 strains under stresses STEC encounter in natural habitats and performed comparative analysis with two O145:H28 clinical strains, one linked to a 2010 U.S. lettuce-associated outbreak (RM13514) and the other linked to a 2007 Belgium ice cream-associated outbreak (RM13516). Similar to the outbreak strains, all environmental strains belong to Sequence Type (ST)-78 using the EcMLST typing scheme. Although all Stx1a-prophages were grouped together, variations in Stx1a production were observed prior to or following the inductions. Among all stx positive environmental strains, only the Stx2a-prophage in cattle isolate RM9154-C1 was clustered with the Stx2a-prophages in RM13514, the Stx2a-phage induced from a STEC O104:H4 strain linked to the 2011 outbreak of enterohemorrhagic infection in Germany, and the Stx2a-prophage in STEC O157:H7 strain EDL933, a prototype of enterohemorrhagic E. coli. Furthermore, the Stx2a-prophage in RM9154-C1 shared the same chromosomal insertion site and carried the same antiterminator Q gene and the late promoter P as the Stx2a-prophage in RM13514. Following mitomycin C or enrofloxacin treatment, the production of Stx2a in RM9154-C1 was the highest among all environmental strains tested. In contrast, following acid challenge and recovery, the production of Stx2a in RM9154-C1 was the lowest among all the environmental strains tested, at a level comparable to the clinical strains. A significant increase in Stx2a production was detected in all strains when exposed to HO, although the induction fold was much lower than those by other inducers. This low-efficiency induction of Stx-prophages by HO, a natural inducer of Stx-prophages, supports the hypothesis of bacterial altruism in controlling Stxs production, a strategy that assures the survival of the STEC population as a whole by sacrificing a small fraction of cells for Stxs production and release. Differential induction of Stxs among strains carrying nearly identical Stx-prophages suggests a role of host bacteria in regulating Stxs production. Our study revealed diverse Stx-prophages in STEC O145:H28 strains that were genotypically indistinguishable. Identification of a cattle isolate harboring a Stx2a-prophage associated with high virulence supports the premise that cattle, a natural reservoir of STEC, serve as a source of hypervirulent STEC strains.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2020.109029DOI Listing
February 2021

Impact of renal function on the prognosis of acute pulmonary embolism patients: a systematic review and meta-analysis.

Expert Rev Respir Med 2020 Dec 31:1-8. Epub 2020 Dec 31.

Department of Orthopedic Surgery, The People's Hospital of Yuxi City, the Sixth Affiliated Hospital of Kunming Medical University, Yuxi, China.

Objectives: We conduct a study to explore the influence of impaired renal function on prognosis in Acute pulmonary embolism (APE) patients.

Methods: A meta-analysis was performed using the EMBASE and PubMed databases for relevant publications reporting the impact of impaired renal function on the clinical outcomes in patients with APE.

Results: Eventually, 17 articles were included in our analysis. The results suggested that renal insufficiency (RI) is a predictor of poor prognosis in APE patients(short-term mortality: pooled OR = 2.83, 95%CI: 2.20-3.63; long-term mortality: pooled OR = 2.30, 95%CI: 1.72-3.08; adverse outcomes: pooled OR = 3.02, 95%CI: 2.60-3.51). The short-term and long-term mortality rates of APE patients with RI were both higher than those in patients without RI. In addition, acute kidney injury(AKI) could serve as a predictive factor of poor prognosis (pooled OR = 2.75, 95%CI: 2.45-3.08), and it doubles the overall mortality rate in APE patients. However, chronic kidney disease (CKD) did not predict poor prognosis in APE patients (pooled OR = 1.94, 95%CI: 0.99-3.81), although it could slightly increase the overall mortality rate in APE patients.

Conclusions: RI and AKI could be included in the prognosis evaluation for APE, but the impact of CKD in APE patients has yet to be determined.
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http://dx.doi.org/10.1080/17476348.2021.1862653DOI Listing
December 2020

Green fabrication of seedbed-like Flammulina velutipes polysaccharides-derived scaffolds accelerating full-thickness skin wound healing accompanied by hair follicle regeneration.

Int J Biol Macromol 2021 Jan 26;167:117-129. Epub 2020 Nov 26.

Department of Biomedical Engineering and Hubei Province Key Laboratory of Allergy and Immune Related Diseases, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China. Electronic address:

A novel seedbed-like scaffold was firstly fabricated by the "frozen sectioning" processing method using Flammulina velutipes as a raw material. The Flammulina velutipes polysaccharides scaffold is composed of a natural structure imitating the "ground" (connected and aligned hollow tubes with porous walls). Meanwhile, its biologically active components include polysaccharides and proteins, mimicking the "plant nutrition" in the seedbed. To further optimize the ground and nutrition components, Flammulina velutipes polysaccharides-derived scaffolds (FPDSs) were fabricated via the treatment of original Flammulina velutipes polysaccharides scaffold (labeled FPS) by NaOH, cysteine (labeled as FPS/NaOH, FPS/Cys, respectively). FPDSs were characterized by SEM, FTIR, XRD, water absorption and retention, and mechanical evaluations. From the results, FPS/NaOH and FPS/Cys lost the characteristic big tubes of original strips and had higher water absorption capacities comparing to FPS. Simultaneously, FPS/NaOH had better ductility, FPS/Cys had showed increased stiffness. Biological activities of FPDSs were tested against different types of bacteria exhibiting excellent anti-bacterial activity, and FPS/NaOH and FPS/Cys had dramatically higher anti-bacterial activity than FPS. The cytocompatibility of FPDSs was evaluated utilizing mouse fibroblast cell line (L929), and all FPDSs showed good cytocompatibility. The FPDSs were further applied to a rat full-thickness skin wound model, and they all exhibited obviously accelerated re-epithelialization, among which FPS/NaOH showed the greatest efficiency. FPS/NaOH could shorten the wound-healing process as evidenced by dynamic alterations of the expression levels of specific stagewise markers in the healing areas. Similarly, FPS/NaOH can efficiently induce hair follicle regeneration in the healing skin tissues. In summary, FPDSs exhibit potential functions as seedbeds to promote the regeneration of the "seed" including hair follicles and injured skin, opening a new avenue for wound healing.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.11.154DOI Listing
January 2021

A biodegradable soy protein isolate-based waterborne polyurethane composite sponge for implantable tissue engineering.

J Mater Sci Mater Med 2020 Nov 28;31(12):120. Epub 2020 Nov 28.

Department of Biomedical Engineering and Hubei Province Key Laboratory of Allergy and Immune Related Diseases, School of Basic Medical Science, Wuhan University, Wuhan, 430071, China.

A biodegradable soy protein isolate-based waterborne polyurethane composite sponge (SWPU) was prepared from soy protein isolate (SPI) and polyurethane prepolymer (PUP) by a process involving chemical reaction and freeze-drying. Effects of SPI content (0, 10%, 30%, 50%, 70%) on the micro-structure and physical properties of the composite sponges were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results showed that the reaction between -NCO of PUP and -NH of SPI formed porous SPI-based WPU composite sponges. The results of the water absorption ratio measurement, solvent resistance measurement and compressive testing showed that water absorption, hydrophilicity, and tensile strength in the dry state of the composite sponges increased with the increase of SPI content. Especially, the tensile strength ranged from 0.3 MPa to 5.5 MPa with the increase in SPI content. The cytocompatibility and biodegradability of the composite sponges were evaluated by in vitro cell culture and in vivo implantation experiments. The results indicated that a certain SPI content in the sponges could promote the adhesion, growth, and proliferation of cells, enhance the cytocompatibility and accelerate the degradation speed of composite sponges. During the in vivo implanting period within 9 months, SWPU-50 sponge containing 50% of SPI brought out the lowest activated inflammatory reaction, most newly-regenerated blood capillaries, and best histocompatibility. All results indicated that SWPU-50 composite sponges had greatest potential for tissue engineering.
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http://dx.doi.org/10.1007/s10856-020-06451-0DOI Listing
November 2020

Validation of a Cell-Based Assay for Detection of Active Shiga Toxins Produced by in Water.

Int J Environ Res Public Health 2020 10 28;17(21). Epub 2020 Oct 28.

Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, 800 Buchanan St., Albany, CA 94710, USA.

Shiga toxin-producing (STEC) causes a wide spectrum of diseases, including hemorrhagic colitis and hemolytic uremic syndrome (HUS). Almost 5% of STEC infections result from waterborne exposures, yet there is no test listed in the EPA's current Selected Analytical Methods for the detection of active Shiga toxins (Stxs) in water. In this study, a HeLa cell-based assay is validated for the detection of metabolically active Stxs produced by STEC in water, including tap, bottled, and pond water. Active Stxs are detected even when the number of Stx-producing bacteria is less than 0.4 CFU/mL and the assay performance is not affected by background flora or chlorine in the water. This assay is not only as simple and affordable as cell-free assays but also detects active holotoxins without the use of live animals. In addition, the assay is designed for use in multi-well formats, making it ideal for high-throughput screening of water samples and therefore useful for environmental public health surveillance programs to reduce human risk of infection with STEC.
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http://dx.doi.org/10.3390/ijerph17217901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663042PMC
October 2020

Development of signature-tagged mutagenesis in Riemerella anatipestifer to identify genes essential for survival and pathogenesis.

Vet Microbiol 2020 Nov 19;250:108857. Epub 2020 Sep 19.

Shanghai Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, China. Electronic address:

Riemerella anatipestifer causes epizootic infectious disease in ducks, geese, turkeys and other birds, and serious economic losses especially to the duck industry. However, little is known about the molecular basis of its pathogenesis. In this study, signature-tagged transposon mutagenesis based on Tn4351 was developed in R. anatipestifer to identify genes essential for survival and pathogenesis. Seventeen tagged Tn4351 random mutation libraries of the R. anatipestifer strain WJ4 containing 5100 mutants were screened for survive using a duckling infection model. Twenty mutants that could not be recovered from the infected ducklings, were identified, and 17 mutated genes were identified by inverse PCR or genome-walking PCR. Of these genes, FIP52_03215, FIP52_04350 and FIP52_09345, were inserted into two mutant strains, and FIP52_03215 and FIP52_03175 were found exclusively on the chromosome of serotype 1 R. anatipestifer strains. Twelve out of 17 genes encoding for proteins were predicted to be involved in amino acid, nucleotide, coenzyme, or lipid transport and metabolism, one gene was predicted to be involved in signal transduction, one gene was predicted to be involved in DNA replication, recombination and repair, the other three genes had an unknown function. Animal experiments showed that the virulence of mutants 16-284, 7-295, 24-231, 9-232 and 19-214 were significantly attenuated compared to that of the wild-type WJ4. Moreover, the median lethal dose of mutant 16-284 was greater than 10 CFU, and its virulence to ducklings was partially restored when it was complemented with the shuttle expression plasmid pRES-FIP52_09345. The results in this study will be helpful to further study the molecular mechanisms of the pathogenesis of R. anatipestifer infection.
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http://dx.doi.org/10.1016/j.vetmic.2020.108857DOI Listing
November 2020

Blockade of Kv1.3 potassium channel inhibits CD8 T cell-mediated neuroinflammation via PD-1/Blimp-1 signaling.

FASEB J 2020 11 27;34(11):15492-15503. Epub 2020 Sep 27.

Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.

Kv1.3 potassium channel is considered as a target for the treatment of autoimmune diseases such as multiple sclerosis (MS), since Kv1.3 blockade suppresses memory T cell activation including cytotoxic CD8 T cells. However, the underlying signaling pathway related to autoimmune CD8 T cell inhibition by Kv1.3 channel in neuroinflammatory diseases remains unclear. We found that ImK, a selective Kv1.3 blocker, reduced auto-reactive CD8 T cell infiltration in the spinal cords of experimental autoimmune encephalomyelitis (EAE) rats, an animal model of MS. ImK suppressed transcriptional factor Blimp-1 expression and reduced the cytotoxicity of CD8 T cells on neuronal cells. Furthermore, ImK upregulated co-inhibitory molecule PD-1 to inhibit B lymphocyte-induced maturation protein (Blimp-1) in an IL-2 independent way. In addition, PD-1 inhibitor impaired the suppression of ImK on CD8 T cells and accelerated EAE progression. Our study demonstrated a novel regulatory mechanism of Kv1.3 blockade on modulating CD8 T cell differentiation through PD-1/Blimp-1 signaling. This work expands the understanding of Kv1.3 channel for modulating neuroinflammation.
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http://dx.doi.org/10.1096/fj.202000861RRDOI Listing
November 2020

Brain Derived Neurotrophic Factor and Glial Cell Line-Derived Neurotrophic Factor-Transfected Bone Mesenchymal Stem Cells for the Repair of Periphery Nerve Injury.

Front Bioeng Biotechnol 2020 30;8:874. Epub 2020 Jul 30.

Department of Biomedical Engineering and Hubei Province Key Laboratory of Allergy and Immune Related Diseases, School of Basic Medical Sciences, Wuhan University, Wuhan, China.

Peripheral nerve injury is a common clinical neurological disease. In our previous study, highly oriented poly (L-lactic acid) (PLLA)/soy protein isolate (SPI) nanofiber nerve conduits were constructed and exhibited a certain repair capacity for peripheral nerve injury. In order to further improve their nerve repairing efficiency, the bone mesenchymal stem cells (BMSCs) overexpressing brain derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) were introduced into the conduits as seed cells and then were used to repair the 10-mm sciatic nerve defects in rats. The nerve repair efficiency of the functional nerve conduits was evaluated by gait experiment, electrophysiological test, and a series of assays such as hemotoxylin-eosin (HE) staining, immunofluorescence staining, toluidine blue (TB) staining, transmission electron microscopy (TEM) observation of regenerated nerve and Masson's trichrome staining of gastrocnemius muscle. The results showed that the conduits containing BMSCs overexpressing BDNF and GDNF double-factors group had better nerve repairing efficiency than blank BMSCs and single BDNF or GDNF factor groups, and superior to autografts group in some aspects. These data demonstrated that BDNF and GDNF produced by BMSCs could synergistically promote peripheral nerve repair. This study shed a new light on the conduits and stem cells-based peripheral nerve repair.
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http://dx.doi.org/10.3389/fbioe.2020.00874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7406647PMC
July 2020

Optimization of low-dose scan parameters in dual-energy computed tomography for displaying the anterior cruciate ligament.

J Int Med Res 2020 Jul;48(7):300060520927874

Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, China.

Objective: This study was performed to assess low-dose scan parameters in dual-energy computed tomography (CT) for displaying the anterior cruciate ligament.

Methods: Dual-energy CT scans with low and standard dose parameters, respectively, were performed in nine human knee joint specimens. Eighteen imaging data sets for cruciate ligament specimens were obtained and processed. Statistical analysis was performed for signal-to-noise ratios of the CT images and subjective scores.

Results: Comparable signal-to-noise ratios and subjective image quality scores by evaluators in dual-energy CT anterior cruciate ligament images between the low and standard-dose groups were observed.

Conclusion: Low-dose scan parameters do not compromise the outcomes of anterior cruciate ligament imaging.
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http://dx.doi.org/10.1177/0300060520927874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7388117PMC
July 2020

Hypoxic Preconditioning Enhances the Efficacy of Mesenchymal Stem Cells-Derived Conditioned Medium in Switching Microglia toward Anti-inflammatory Polarization in Ischemia/Reperfusion.

Cell Mol Neurobiol 2021 Apr 18;41(3):505-524. Epub 2020 May 18.

Department of Pathophysiology & Hubei Province Key Laboratory of Allergy and Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China.

Activation of pro-inflammatory microglia is an important mechanism of the cerebral ischemia-reperfusion (I/R)-induced neuronal injury and dysfunction. Mesenchymal stem cells (MSCs) together with their paracrine factors demonstrated curative potential in immune disorders and inflammatory diseases, as well as in ischemic diseases. However, it remains unclear whether conditioned medium from MSCs could effectively regulate the activation and polarization of microglia exposed to I/R stimulation. In this study, we investigated the effects of conditioned medium from bone marrow MSCs (BMSCs-CM) on I/R-stimulated microglia and the potential mechanism involved, as well as the way to obtain more effective BMSCs-CM. First, cell model of oxygen-glucose deprivation/reoxygenation (OGD/R) was established in microglia to mimic the I/R. BMSCs-CM from different culture conditions (normoxic: 21% O; hypoxic: 1% O; hypoxia preconditioning: preconditioning with 1% O for 24 h) was used to treat the microglia. Our results showed that BMSCs-CM effectively promoted the survival and alleviated the injury of microglia. Moreover, in microglia exposed to OGD/R, BMSCs-CM inhibited significantly the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), CD86 and inducible nitric oxide synthase, whereas upregulated the levels of anti-inflammatory cytokine (IL-10), CD206 and Arginase-1. These results suggested that BMSCs-CM promoted the polarization of anti-inflammatory microglia. In particular, BMSCs-CM from cultures with hypoxia preconditioning was more effective in alleviating cell injury and promoting anti-inflammatory microglia polarization than BMSCs-CM from normoxic cultures and from hypoxic cultures. Furthermore, inhibition of exosomes secretion could largely mitigate these effects of BMSCs-CM. In conclusion, our results suggested that hypoxia preconditioning of BMSCs could enhance the efficacy of BMSCs-CM in alleviating OGD/R-induced injury and in promoting the anti-inflammatory polarization of microglia, and these beneficial effects of BMSCs-CM owed substantially to exosomes.
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http://dx.doi.org/10.1007/s10571-020-00868-5DOI Listing
April 2021

Inhibition of the NLRP3-inflammasome prevents cognitive deficits in experimental autoimmune encephalomyelitis mice via the alteration of astrocyte phenotype.

Cell Death Dis 2020 05 15;11(5):377. Epub 2020 May 15.

Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.

Multiple sclerosis (MS) is a chronic disease that is characterized by demyelination and axonal damage in the central nervous system. Cognitive deficits are recognized as one of the features of MS, and these deficits affect the patients' quality of life. Increasing evidence from experimental autoimmune encephalomyelitis (EAE), the animal model of MS, has suggested that EAE mice exhibit hippocampal impairment and cognitive deficits. However, the underlying mechanisms are still unclear. The NLRP3 inflammasome is a key contributor to neuroinflammation and is involved in the development of MS and EAE. Activation of the NLRP3 inflammasome in microglia is fundamental for subsequent inflammatory events. Activated microglia can convert astrocytes to the neurotoxic A1 phenotype in a variety of neurological diseases. However, it remains unknown whether the NLRP3 inflammasome contributes to cognitive deficits and astrocyte phenotype alteration in EAE. In this study, we demonstrated that severe memory deficits occurred in the late phase of EAE, and cognitive deficits were ameliorated by treatment with MCC950, an inhibitor of the NLRP3 inflammasome. In addition, MCC950 alleviated hippocampal pathology and synapse loss. Astrocytes from EAE mice were converted to the neurotoxic A1 phenotype, and this conversion was prevented by MCC950 treatment. IL-18, which is the downstream of NLRP3 inflammasome, was sufficient to induce the conversion of astrocytes to the A1 phenotype through the NF-κB pathway. IL-18 induced A1 type reactive astrocytes impaired hippocampal neurons through the release of complement component 3 (C3). Altogether, our present data suggest that the NLRP3 inflammasome plays an important role in cognitive deficits in EAE, possibly via the alteration of astrocyte phenotypes. Our study provides a novel therapeutic strategy for hippocampal impairment in EAE and MS.
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http://dx.doi.org/10.1038/s41419-020-2565-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7229224PMC
May 2020

Rapid and Label-Free Immunosensing of Shiga Toxin Subtypes with Surface Plasmon Resonance Imaging.

Toxins (Basel) 2020 04 26;12(5). Epub 2020 Apr 26.

USDA, ARS, PWA, WRRC, 800 Buchanan Street, Albany, CA 94710, USA.

Shiga toxin-producing (STEC) are responsible for gastrointestinal diseases reported in numerous outbreaks around the world as well as in the United States. Current detection methods have limitation to implement for rapid field-deployable detection with high volume of samples that are needed for regulatory purposes. Surface plasmon resonance imaging (SPRi) has proved to achieve rapid and label-free screening of multiple pathogens simultaneously, so it was evaluated in this work for the detection of Shiga toxins (Stx1a and Stx2a toxoids were used as the less toxic alternatives to Stx1 and Stx2, respectively). Multiple antibodies (Stx1pAb, Stx1-1mAb, Stx1-2mAb, Stx1d-3mAb, Stx1e-4mAb, Stx2pAb, Stx2-1mAb, Stx2-2mAb, and Stx2-10mAb) were spotted one by one by programed microarrayer, on the same high-throughput biochip with 50-nm gold film through multiple crosslinking and blocking steps to improve the orientation of antibodies on the biochip surface. Shiga toxins were detected based on the SPRi signal difference (ΔR) between immobilized testing antibodies and immunoglobulin G (IgG) control. Among the antibodies tested, Stx1pAb showed the highest sensitivity for Stx1 toxoid, with the limit of detection (LOD) of 50 ng/mL and detection time of 20 min. Both Stx2-1mAb and Stx2-2mAb exhibited high sensitivity for Stx2 toxoid. Furthermore, gold nanoparticles (GNPs) were used to amplify the SPRi signals of monoclonal antibodies in a sandwich platform. The LOD reached the level of picogram (pg)/mL with the help of GNP-antibody conjugate. This result proved that SPRi biochip with selected antibodies has the potential for rapid, high-throughput and multiplex detection of Shiga toxins.
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http://dx.doi.org/10.3390/toxins12050280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7291228PMC
April 2020

Aligned soy protein isolate-modified poly(L-lactic acid) nanofibrous conduits enhanced peripheral nerve regeneration.

J Neural Eng 2020 06 2;17(3):036003. Epub 2020 Jun 2.

Department of Biomedical Engineering and Hubei Province Key Laboratory of Allergy and Immune Related Diseases, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, People's Republic of China. Hangzhou Singclean Medical Products Co., Ltd., Hangzhou 310018, People's Republic of China.

Objective: Repair and regeneration of peripheral nerve defect by engineered conduits have greatly advanced in the past decades while still facing great challenges.

Approach: In this work, we fabricated a new highly oriented poly(L-lactic acid) (PLLA)/soy protein isolate (SPI) nanofibrous conduit (HO-PSNC) for nerve regeneration.

Main Results: Firstly, we observed that SPI could efficiently modify PLLA for the electrospinning of PLLA/SPI nanofibers with enhanced physical and biological properties. Incorporation of SPI decreased the fiber diameter and ductility of PLLA/SPI nanofibrous films (PSNFs), improved the tensile strength and surface wettability of PSNFs and increased the in vivo degradability of the PSNFs. When the hybrid ratio of SPI was 20 and 40%, PSNFs could efficiently promote neural cell extension and differentiation in vitro. Based on these data, 20% SPI (PSNF-20) was chosen for further investigation. Next, PSNF-20 with different fiber orientations (random/low orientation, medium, and high orientation, respectively) were developed and used for evaluating neural cell behaviors on the materials. Results revealed that the PSNF-20 with highly oriented nanofibers (HO-PSNF-20) or mediumly oriented nanofibers (MO-PSNF-20) showed a better performance in directing cell extension and enhancing neurite outgrowth. Finally, the highly oriented nanofibers conduits (HO-PSNC-20) were used to bridge sciatic nerve defect in rats with highly oriented PLLA and autografts as controls. HO-PSNC-20 exhibited a significant promotion in nerve regeneration and functional reconstruction comparing to highly oriented PLLA as proven by the evaluations of walking track, electrophysiology, toluidine blue nerve staining, transmission electron microscopy, neural factors staining and qPCR, and gastrocnemius histology.

Significance: In conclusion, nerve conduit fabricated from aligned electrospinning of SPI-modified PLLA nanofibers is promising for peripheral nerve regeneration.
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http://dx.doi.org/10.1088/1741-2552/ab8d81DOI Listing
June 2020

Antifungal Application of Rosin Derivatives from Renewable Pine Resin in Crop Protection.

J Agric Food Chem 2020 Apr 25;68(14):4144-4154. Epub 2020 Mar 25.

Department of Chemistry and Biochemistry, University of Michigan-Flint, Flint, Michigan 48502, United States.

In the current work, we synthesized two series of dehydroabietyl amide derivatives from natural product rosin and evaluated their antifungal effects on , , , , and . and antifungal activities results indicated that rosin-based amide compounds containing thiophene heterocycles had better inhibitory effects on . In particular, compound (5-fluoro-2-thiophene dehydroabietyl amide) exhibited the excellent antifungal properties against with an EC of 0.490 mg/L, which was lower compared to the positive control penthiopyrad (0.562 mg/L). Physiological and biochemical studies showed that the primary action mechanism of compound on changes mycelial morphology, increases cell membrane permeability, and inhibits the TCA pathway in respiratory metabolism. Furthermore, QSAR and SAR studies revealed that charge distribution of rosin-based amides derivatives have a key role in the antifungal activity through the hydrogen bonding, conjugation, and electrostatic interaction between the compounds and the receptors of the target. To sum up, this study contributes to the development of rosin-based antifungal agents with a novel structure and preferable biological activity.
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http://dx.doi.org/10.1021/acs.jafc.0c00562DOI Listing
April 2020

Genomic Insight into Natural Inactivation of Shiga Toxin 2 Production in an Environmental Strain Producing Shiga Toxin 1.

Foodborne Pathog Dis 2020 09 4;17(9):555-567. Epub 2020 Mar 4.

Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California.

Shiga toxin-producing (STEC) consists of a group of diverse strains differing greatly in genetic make-up and pathogenicity potential. Here, we investigated production of Shiga toxins (Stxs) in a bovine isolate carrying multiple Shiga toxin genes (s) after exposure to several antibiotics commonly used in food animals. Strain RM10809-C3 was co-isolated with a STEC O145:H28 strain from cattle feces near a leafy greens-growing region in California. The genome of RM10809-C3 is composed of a 5,128,479-bp chromosome and a 122,641-bp plasmid, encoding 5108 coding sequences. Strain RM10809-C3 belongs to serotype O22:H8 and is clustered together with two STEC O168:H8 food isolates using either multilocus sequence type or core genome-based phylogenetic analysis. Six intact prophages were identified in the genome of RM10809-C3, among which prophage 4 contained two sets of ; whereas prophage 9 carried one set of . Increased production of Stx1 was detected in RM10809-C3 after exposure to mitomycin C and enrofloxacin, but not in cells exposed to tetracycline. In contrast, Stx2 remained undetectable in cells treated with any of the antibiotics examined. Comparison of Stx-converting prophages in strain RM10809-C3 with those in strain EDL933 revealed altered promoters in RM10809-C3, including deletion of the late promoter and the mutations in , the binding site of antitermination protein Q. In contrast, both and within the promoter of in RM10809-C3 were identical to the corresponding one in EDL933. Further, the protein Q encoded by Stx1-prophage in RM10809-C3 exhibited >94% identity with either of the two EDL933 protein Q; whereas both protein Q encoded by Stx2-prophage in RM10809-C3 were distantly related to any of the EDL933 protein Q. Natural silence of Stx2 production in strain RM10809-C3 emphasizes that not only the coding regions but also their regulatory factors are important in STEC risk assessment.
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http://dx.doi.org/10.1089/fpd.2019.2767DOI Listing
September 2020

HDAC6, A Novel Cargo for Autophagic Clearance of Stress Granules, Mediates the Repression of the Type I Interferon Response During Coxsackievirus A16 Infection.

Front Microbiol 2020 31;11:78. Epub 2020 Jan 31.

Hubei Province Key Laboratory of Allergy and Immunology, Department of Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.

Autophagic cargoes ensure selective autophagy for the recognition and removal of various cytosolic aggregated proteins, damaged organelles, or pathogens. Stress granules (SGs), as antiviral immune complexes, serve a positive role in the type I interferon (IFN) response and can be targeted by autophagy (termed granulophagy). However, the cargo of granulophagy remains elusive, and it is still unknown whether granulophagy plays a role in viral infection. Here, we found that histone deacetylase 6 (HDAC6), a component of viral RNA-induced SGs, is a novel granulophagic cargo that is recognized by p62/Sequestosome 1 (SQSTM1) and mediates the degradation of SGs in coxsackievirus A16 (CA16)-infected cells. CA16 viral RNA activated the protein kinase RNA-activated (PKR)/eukaryotic translation initiation factor 2-alpha (eIF2α) pathway to promote SG assembly. The SGs were degraded by CA16-triggered autophagy via the interaction between the ubiquitin-associated (UBA) domain of p62 and the ubiquitin-binding domain (UBD) of HDAC6, which was bridged by a poly-ubiquitin chain. We also found that granulophagy repressed the type I interferon response and facilitated viral replication. These results suggest that HDAC6 might be the first identified granulophagic cargo and granulophagy could be a strategy that viruses apply to repress the antiviral immune response.
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http://dx.doi.org/10.3389/fmicb.2020.00078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7005486PMC
January 2020

The Late Domain of Prototype Foamy Virus Gag Facilitates Autophagic Clearance of Stress Granules by Promoting Amphisome Formation.

J Virol 2020 03 17;94(7). Epub 2020 Mar 17.

Hubei Province Key Laboratory of Allergy and Immunology, Department of Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China

Prototype foamy virus (PFV), a complex retrovirus belonging to , maintains lifelong latent infection. The maintenance of lifelong latent infection by viruses relies on the repression of the type I interferon (IFN) response. However, the mechanism involving PFV latency, especially regarding the suppression of the IFN response, is poorly understood. Our previous study showed that PFV promotes autophagic flux. However, the underlying mechanism and the role of PFV-induced autophagy in latent infection have not been clarified. Here, we report that the PFV viral structural protein Gag induced amphisome formation and triggered autophagic clearance of stress granules (SGs) to attenuate type I IFN production. Moreover, the late domain (L-domain) of Gag played a central role in Alix recruitment, which promoted endosomal sorting complex required for transport I (ESCRT-I) formation and amphisome accumulation by facilitating late endosome formation. Our data suggest that PFV Gag represses the host IFN response through autophagic clearance of SGs by activating the endosome-autophagy pathway. More importantly, we found a novel mechanism by which a retrovirus inhibits the SG response to repress the type I IFN response. Maintenance of lifelong latent infection for viruses relies on repression of the type I IFN response. Autophagy plays a double-edged sword in antiviral immunity. However, the role of autophagy in the regulation of the type I IFN response and the mechanism involving virus-promoted autophagy have not been fully elucidated. SGs are an immune complex associated with the antiviral immune response and are critical for type I IFN production. Autophagic clearance of SGs is one means of degradation of SGs and is associated with regulation of immunity, but the detailed mechanism remains unclear. In this article, we demonstrate that PFV Gag recruits ESCRT-I to facilitate amphisome formation. Our data also suggest that amphisome formation is a critical event for autophagic clearance of SGs and repression of the type I IFN response. More importantly, we found a novel mechanism by which a retrovirus inhibits the SG response to repress the type I IFN response.
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http://dx.doi.org/10.1128/JVI.01719-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7081917PMC
March 2020

LncRNA MIR4435-2HG-mediated upregulation of TGF-β1 promotes migration and proliferation of nonsmall cell lung cancer cells.

Environ Toxicol 2020 May 25;35(5):582-590. Epub 2019 Dec 25.

Department of Respiratory and Critical Care, Yunnan Second People's Hospital, Kunming City, Yunnan Province, China.

The roles of long noncoding RNAs (lncRNAs) have been shown to play critical roles in tumor progression. Here, it was identified that lncRNA MIR4435-2HG was highly expressed in lung cancer tissues, especially in nonsmall cell lung cancer (NSCLC). A consistent result was obtained in lung cancer cells. Functional experiments showed that knockdown of MIR4435-2HG reduced the proliferation and migration ability of NSCLC cells. Transcriptome-sequencing analysis indicated that TGF-β signaling was mostly enriched in NSCLC cells with MIR4435-2HG knockdown. Furthermore, MIR4435-2HG was identified as an miRNA sponge for TGF-β1 and thus activated TGF-β signaling. Additionally, re-activation of TGF-β1 rescued MIR4435-2HG knockdown-mediated inhibition on the progression of NSCLC cells. Therefore, this work indicates a novel MIR4435-2HG/TGF-β1 axis responsible for NSCLC cell progression.
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http://dx.doi.org/10.1002/tox.22893DOI Listing
May 2020

Structural and Functional Characterization of Stx2k, a New Subtype of Shiga Toxin 2.

Microorganisms 2019 Dec 18;8(1). Epub 2019 Dec 18.

Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, 800 Buchanan St., Albany, CA 94710, USA.

Shiga toxin (Stx) is the major virulence factor of Shiga toxin-producing (STEC). Stx evolves rapidly and, as such, new subtypes continue to emerge that challenge the efficacy of existing disease management and surveillance strategies. A new subtype, Stx2k, was recently identified in isolated from a wide range of sources including diarrheal patients, animals, and raw meats, and was poorly detected by existing immunoassays. In this study, the structure of Stx2kE167Q was determined at 2.29 Å resolution and the conservation of structure with Stx2a was revealed. A novel polyclonal antibody capable of neutralizing Stx2k and an immunoassay, with a 10-fold increase in sensitivity compared to assays using extant antibodies, were developed. Stx2k is less toxic than Stx2a in Vero cell assays but is similar to Stx2a in receptor-binding preference, thermostability, and acid tolerance. Although Stx2k does not appear to be as potent as Stx2a to Vero cells, the wide distribution and blended virulence profiles of the Stx2k-producing strains suggest that horizontal gene transfer through Stx2k-converting phages could result in the emergence of new and highly virulent pathogens. This study provides useful information and tools for early detection and control of Stx2k-producing , which could reduce public risk of infection by less-known STECs.
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http://dx.doi.org/10.3390/microorganisms8010004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022315PMC
December 2019

Particulate Shiga Toxin 2 in Blood is Associated to the Development of Hemolytic Uremic Syndrome in Children.

Thromb Haemost 2020 Jan 13;120(1):107-120. Epub 2019 Dec 13.

Center for HUS Prevention Control and Management, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.

Hemolytic uremic syndrome (HUS), the leading cause of acute renal failure in children (< 3 years), is mainly related to Shiga toxins (Stx)-producing (STEC) infections. STEC are confined to the gut resulting in hemorrhagic colitis, whereas Stx are delivered in blood to target kidney and brain, with unclear mechanisms, triggering HUS in 5 to 15% of infected children. Stx were found on circulating cells, free in sera (soluble Stx) or in blood cell-derived microvesicles (particulate Stx), whereby the relationship between these forms of circulating toxins is unclear. Here, we have examined 2,846 children with bloody diarrhea and found evidence of STEC infection in 5%. Twenty patients were enrolled to study the natural course of STEC infections before the onset of HUS. In patients, Stx were found to be associated to circulating cells and/or free and functionally active in sera. In most children, Stx were bound to neutrophils when high amounts of toxins were found in feces. Time-course analysis showed that Stx increased transiently in patients' sera while the decrease of toxin amount on leukocytes was observed. Notably, patients who recovered (85%) displayed different settings than those who developed HUS (15%). The distinctive feature of the latter group was the presence in blood of particulate Stx2 (Stx2 sedimented at -forces corresponding to 1 μm microvesicles) the day before diagnosis of HUS, during the release phase of toxins from circulating cells. This observation strongly suggests the involvement of blood cell-derived particulate Stx2 in the transition from hemorrhagic colitis to HUS.
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http://dx.doi.org/10.1055/s-0039-3400301DOI Listing
January 2020

Escherichia coli strains producing a novel Shiga toxin 2 subtype circulate in China.

Int J Med Microbiol 2020 Jan 9;310(1):151377. Epub 2019 Nov 9.

State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang Province, China. Electronic address:

Shiga toxin (Stx) is the key virulence factor in Shiga toxin producing Escherichia coli (STEC), which can cause diarrhea and hemorrhagic colitis with life-threatening complications. Stx comprises two toxin types, Stx1 and Stx2. Several Stx1/Stx2 subtypes have been identified in E. coli, which are variable in sequences, toxicity and host specificity. Here, we report the identification of a novel Stx2 subtype, designated Stx2k, in E. coli strains widely detected from diarrheal patients, animals, and raw meats in China over time. Stx2k exhibits varied cytotoxicity in vitro among individual strains. The Stx2k converting prophages displayed considerable heterogeneity in terms of insertion site, genetic content and structure. Whole genome analysis revealed that the stx-containing strains were genetically heterogeneous with diverse serotypes, sequence types, and virulence gene profiles. The nine stx-containing strains formed two major phylogenetic clusters closely with strains belonging to STEC, enterotoxigenic E. coli (ETEC), and STEC/ETEC hybrid. One stx-containing strain harbored one plasmid-encoded heat-stable enterotoxin sta gene and two identical copies of chromosome-encoded stb gene, exhibiting STEC/ETEC hybrid pathotype. Our finding enlarges the pool of Stx2 subtypes and highlights the extraordinary genomic plasticity of STEC strains. Given the wide distribution of the Stx2k-producing strains in diverse sources and their pathogenic potential, Stx2k should be taken into account in epidemiological surveillance of STEC infections and clinical diagnosis.
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http://dx.doi.org/10.1016/j.ijmm.2019.151377DOI Listing
January 2020