PRMT5 Facilitates Infectious Bursal Disease Virus Replication through Arginine Methylation of VP1.

The infectious bursal diseases virus (IBDV) polymerase, VP1 protein, is responsible for transcription, initial translation and viral genomic replication. Knowledge about the new kind of post-translational modification of VP1 supports identification of novel drugs against the virus. Because the arginine residue is known to be methylated by protein arginine methyltransferase (PRMT) enzyme, we investigated whether IBDV VP1 is a substrate for known PRMTs. In this study, we show that VP1 is specifically associated with and methylated by PRMT5 at the arginine 426 (R426) residue. IBDV infection causes the accumulation of PRMT5 in the cytoplasm, which colocalizes with VP1 as a punctate structure. In addition, ectopic expression of PRMT5 significantly enhances the viral replication. In the presence of PMRT5, enzyme inhibitor and knockout of PRMT5 remarkably decreased viral replication. The polymerase activity of VP1 was severely damaged when R426 mutated to alanine, resulting in impaired viral replication. Our study reports a novel form of post-translational modification of VP1, which supports its polymerase function to facilitate the viral replication. IMPORTANCE Post-translational modification of infectious bursal disease virus (IBDV) VP1 is important for the regulation of its polymerase activity. Investigation of the significance of specific modification of VP1 can lead to better understanding of viral replication and can probably also help in identifying novel targets for antiviral compounds. Our work demonstrates the molecular mechanism of VP1 methylation mediated by PRMT5, which is critical for viral polymerase activity, as well as viral replication. Our study expands a novel insight into the function of arginine methylation of VP1, which might be useful for limiting the replication of IBDV.

Phosphorylation of VP1 Mediated by CDK1-Cyclin B1 Facilitates Infectious Bursal Disease Virus Replication.

Infectious bursal disease virus (IBDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Avibirnavirus in the family Birnaviridae. It can cause serious failure of vaccination in young poultry birds with impaired immune systems. Post-translational modifications of the VP1 protein are essential for viral RNA transcription, genome replication, and viral multiplication. Little information is available so far regarding the exact mechanism of phosphorylation of IBDV VP1 and its significance in the viral life cycle. Here, we provide several lines of evidence that the cyclin-dependent kinase 1 (CDK1)-cyclin B1 complex phosphorylates VP1, which facilitates viral replication. We show that the CDK1-cyclin B1 specifically interacts with VP1 and phosphorylates VP1 on the serine 7 residue, located in the N-terminal 7SPAQ10 region, which follows the optimal phosphorylation motif of CDK1, p-S/T-P. Additionally, IBDV infection drives the cytoplasmic accumulation of CDK1-cyclin B1, which co-localizes with VP1, supporting the kinase activity of CDK1-cyclin B1. Treatment with CDK1 inhibitor RO3306 and knockdown of CDK1-cyclin B1 severely disrupts the polymerase activity of VP1, resulting in diminished viral replication. Moreover, the replication of S7A mutant recombinant IBDV was significantly decreased compared to that of wild-type (WT) IBDV. Thus, CDK1-cyclin B1 is a crucial enzyme which phosphorylates IBDV VP1 on serine 7, which is necessary both for the polymerase activity of VP1 and for viral replication. IMPORTANCE Infectious bursal disease virus still poses a great economic threat to the global poultry farming industry. Detailed information on the steps of viral genome replication is essential for the development of antiviral therapeutics. Phosphorylation is a common post-translational modification in several viral proteins. There is a lack of information regarding the significance of VP1 phosphorylation and its role in modulating the viral life cycle. In this study, we found that CDK1-cyclin B1 accumulates in the cytoplasm and phosphorylates VP1 on serine 7. The presence of a CDK1 inhibitor and the silencing of CDK1-cyclin B1 decrease IBDV replication. The mutation of VP1 serine 7 to alanine reduces VP1 polymerase activity, disrupting the viral life cycle, which suggests that this residue serves an essential function. Our study offers novel insights into the regulatory mechanism of VP1 phosphorylation.

Identification of a novel porcine Teschovirus 2 strain as causative agent of encephalomyelitis in suckling piglets with high mortality in China.

BACKGROUND: Porcine Teschovirus (PTV), also named Teschovirus A, is prevalent in pig populations, mainly causing neurological symptoms, diarrhea, pneumonia, and reproductive failure, however the morbidity and mortality are usually low in pig farms. CASE PRESENTATION: In this study, we reported a PTV outbreak investigation in one large-scale pig farm in China with severe symptoms including diarrhea, lethargy, locomotor ataxia, nystagmus, paralysis of the hind limbs, and coma in piglets. More importantly, the mortality reached 38% in suckling pigs, which is remarkably high in PTV history. A novel PTV strain, named HeNZ1, was isolated from cerebral samples of one suckling pig and the genome sequence was obtained by NGS sequencing. Phylogenetic and evolutionary divergence analyses revealed that HeNZ1 belongs to PTV genotype 2. Surprisingly, the VP1 coding region of HeNZ1 shares the highest sequence similarity with European PTV-2 strains, instead of China domestic PTV-2 strains, implying it may not derive from China local PTV-2 strains. Multiple sequence alignment and B cell epitope prediction of PTV VP1 and VP2 protein revealed 10 B cell epitopes, 5 mutant clusters and 36 unique mutation sites, of which 19 unique mutation sites are located in B cell epitopes and exposed on the surface of VP1 or VP2, implying significant antigenic drift potential of HeNZ1. CONCLUSION: These results indicate that HeNZ1 is a highly virulent PTV-2 strain, which capable of causing severe neurological symptoms and high mortality in piglets. Bioinformatic analysis suggest that HeNZ1 is genetically and antigenically different from other Chinese PTV-2 strains. Overall, current case expanded our understanding of PTV-2 clinical spectrum and revealed the emergence of a highly virulent PTV-2 strain with substantial genetic diversity and antigenic drift potential in VP1 and VP2.

Bone mesenchymal stem cells stimulation by magnetic nanoparticles and a static magnetic field: release of exosomal miR-1260a improves osteogenesis and angiogenesis.

BACKGROUND: The therapeutic potential of exosomes derived from stem cells has attracted increasing interest recently, because they can exert similar paracrine functions of stem cells and overcome the limitations of stem cells transplantation. Exosomes derived from bone mesenchymal stem cells (BMSC-Exos) have been confirmed to promote osteogenesis and angiogenesis. The magnetic nanoparticles (eg. Fe3O4, γ-Fe2O3) combined with a static magnetic field (SMF) has been commonly used to increase wound healing and bone regeneration. Hence, this study aims to evaluate whether exosomes derived from BMSCs preconditioned with a low dose of Fe3O4 nanoparticles with or without the SMF, exert superior pro-osteogenic and pro-angiogenic activities in bone regeneration and the underlying mechanisms involved. METHODS: Two novel types of exosomes derived from preconditioned BMSCs that fabricated by regulating the contents with the stimulation of magnetic nanoparticles and/or a SMF. Then, the new exosomes were isolated by ultracentrifugation and characterized. Afterwards, we conducted in vitro experiments in which we measured osteogenic differentiation, cell proliferation, cell migration, and tube formation, then established an in vivo critical-sized calvarial defect rat model. The miRNA expression profiles were compared among the exosomes to detect the potential mechanism of improving osteogenesis and angiogenesis. At last, the function of exosomal miRNA during bone regeneration was confirmed by utilizing a series of gain- and loss-of-function experiments in vitro. RESULTS: 50 µg/mL Fe3O4 nanoparticles and a 100 mT SMF were chosen as the optimum magnetic conditions to fabricate two new exosomes, named BMSC-Fe3O4-Exos and BMSC-Fe3O4-SMF-Exos. They were both confirmed to enhance osteogenesis and angiogenesis in vitro and in vivo compared with BMSC-Exos, and BMSC-Fe3O4-SMF-Exos had the most marked effect. The promotion effect was found to be related to the highly riched miR-1260a in BMSC-Fe3O4-SMF-Exos. Furthermore, miR-1260a was verified to enhance osteogenesis and angiogenesis through inhibition of HDAC7 and COL4A2, respectively. CONCLUSION: These results suggest that low doses of Fe3O4 nanoparticles combined with a SMF trigger exosomes to exert enhanced osteogenesis and angiogenesis and that targeting of HDAC7 and COL4A2 by exosomal miR-1260a plays a crucial role in this process. This work could provide a new protocol to promote bone regeneration for tissue engineering in the future.

Error tracking-control-reduction algorithm for designing diffractive optical element with high image reconstruction quality.

The use of the diffractive optical element (DOE) can often significantly reduce the size and enhance the performance of the optical system, but it is mostly prevented by low diffraction efficiency and serious speckle noise due to the quantization error. In this paper, an error tracking-control-reduction (ETCR) algorithm is proposed to suppress the quantization error, which adjusts the accumulative action, controls the current state and predicts the trend of the error. The simulation and experiment results verify that the ETCR algorithm has high diffraction efficiency which can be comparable with the Gerchberg-Saxton (GS) and Modified GS algorithms. Furthermore, the root-mean-square error (RMSE) of the proposed algorithm is significantly lower than that of the GS and MGS algorithms. Based on the proposed method, a 2-level DOE has been designed and fabricated to generate several grey images with only 0.05 RMSE.

Are Routine Postoperative Laboratory Tests Necessary After Primary Total Hip Arthroplasty?

BACKGROUND: Recently, the practice of ordering routine postoperative laboratory tests in primary total hip arthroplasty (THA) has been challenged. This study aimed to evaluate the utility of routine postoperative laboratory tests after primary elective THA in an Asian population and identify the risk factors associated with abnormal postoperative laboratory test-related intervention. METHODS: We retrospectively reviewed 395 consecutive patients who underwent primary elective THA at a single tertiary academic center. Patient clinical information and laboratory test results were collected for analysis. RESULTS: A total of 349 (88.4%) patients had abnormal postoperative laboratory test results; most patients had anemia and hypoalbuminemia. Twenty-seven (6.8%) patients received clinical intervention. Of the 307 (77.7%) patients with postoperative anemia, 7 patients received blood transfusion. Factors associated with transfusion were female gender, low body mass index, long operation time, and low preoperative hemoglobin levels. Of the 149 (37.7%) patients with postoperative hypoalbuminemia, 16 received albumin supplementation. Factors associated with albumin supplementation were female gender, long operation time, and low preoperative albumin levels. Although 36 patients had abnormal postoperative creatinine, only 1 patient required specialist consultation. For electrolyte abnormalities, hyponatremia was noted; however, no patient received sodium supplementation. Moreover, 14 patients developed hypokalemia, of which 6 required potassium supplementation; 163 patients had hypocalcemia, of which 2 received calcium supplementation. CONCLUSION: Routine laboratory tests after primary elective THA are unnecessary for most of the patients in modern clinical practice. However, for those with identified risk factors, postoperative laboratory tests still should be performed.

Bioavailability and Speciation of Heavy Metals in Polluted Soil as Alleviated by Different Types of Biochars.

Biochar is an important material for remediation of contaminated soils, however, different biochars have variable effects on bioavailability of heavy metals. This experiment revealed that peanut shell biochar (PSB) has highest reduction of 78% concentration of Pb in plant roots. The maize straw biochar (MSB) has significantly decreased Zn and Cd concentration (mg/kg dry weight) in Chinese cabbage than other treatments of biochars. The plants of Chinese cabbage have exhibited an efficient transport capability for Zn and Cd. The biochars have reduced exchangeable form of Cd/Zn, enhanced residual heavy metals, and consequently diminished accumulation of heavy metals in plants. The straw block biochar (SBB), PSB and MSB have efficiently relieved the stresses of heavy metals in plants.

The necessity of routine postoperative laboratory tests after total hip arthroplasty for hip fracture in a semi-urgent clinical setting.

BACKGROUND: Recent studies suggest that routine postoperative laboratory tests are not necessary after primary elective total hip arthroplasty (THA). This study aims to evaluate the utility of routine postoperative laboratory tests in patients undergoing THA for hip fracture in a semi-urgent clinical setting. MATERIALS AND METHODS: This retrospective study included 213 consecutive patients who underwent primary unilateral THA for hip fractures. Patient demographics, clinical information, and laboratory tests were obtained from the electronic medical record system. Multivariate logistic regression analysis was performed to identify risk factors associated with abnormal laboratory test-related interventions. RESULTS: A total of 207 patients (97.18%) had abnormal postoperative laboratory results, which were mainly due to anemia (190/213, 89.20%) and hypoalbuminemia (154/213, 72.30%). Overall, 54 patients (25.35%) underwent a clinical intervention, 18 patients received blood transfusion, and 42 patients received albumin supplementation. Factors associated with blood transfusion were long operative time and low preoperative hemoglobin levels. Factors associated with albumin supplementation were long operative time and low preoperative albumin levels. Of the 33 patients with abnormal postoperative creatinine levels, 7 patients underwent a clinical intervention. For electrolyte abnormalities, sodium supplementation was not given for hyponatremia, three patients received potassium supplementation, and one patient received calcium supplementation. CONCLUSIONS: This study demonstrated a high incidence of abnormal postoperative laboratory tests and a significant clinical intervention rate in patients who underwent THA for hip fracture in a semi-urgent clinical setting, which indicates that routine laboratory tests after THA for hip fracture are still necessary for patients with certain risk factors. LEVEL OF EVIDENCE: Level III. Trial registration Clinical trial registry number ChiCTR1900020690.

Suppression of Hepatic FLOT1 (Flotillin-1) by Type 2 Diabetes Mellitus Impairs the Disposal of Remnant Lipoproteins via Syndecan-1.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) and the atherometabolic syndrome exhibit a deadly dyslipoproteinemia that arises in part from impaired hepatic disposal of C-TRLs (cholesterol- and triglyceride-rich remnant apoB [apolipoprotein B] lipoproteins). We previously identified syndecan-1 as a receptor for C-TRLs that directly mediates endocytosis via rafts, independent from coated pits. Caveolins and flotillins form rafts but facilitate distinct endocytotic pathways. We now investigated their participation in syndecan-1-mediated disposal of C-TRLs and their expression in T2DM liver. APPROACH AND RESULTS: In cultured liver cells and nondiabetic murine livers, we found that syndecan-1 coimmunoprecipitates with FLOT1 (flotillin-1) but not with CAV1 (caveolin-1). Binding of C-TRLs to syndecan-1 on the surface of liver cells enhanced syndecan-1/FLOT1 association. The 2 molecules then trafficked together into the lysosomes, implying limited if any recycling back to the cell surface. The interaction requires the transmembrane/cytoplasmic region of syndecan-1 and the N-terminal hydrophobic domain of FLOT1. Knockdown of FLOT1 in cultured liver cells substantially inhibited syndecan-1 endocytosis. Livers from obese, T2DM KKAy mice exhibited 60% to 70% less FLOT1 protein and mRNA than in nondiabetic KK livers. An adenoviral construct to enhance hepatic expression of wild-type FLOT1 in T2DM mice normalized plasma triglycerides, whereas a mutant FLOT1 missing its N-terminal hydrophobic domain had no effect. Moreover, the adenoviral vector for wild-type FLOT1 lowered plasma triglyceride excursions and normalized retinyl excursions in T2DM KKAy mice after a corn oil gavage, without affecting postprandial production of C-TRLs. CONCLUSIONS: FLOT1 is a novel participant in the disposal of harmful C-TRLs via syndecan-1. Low expression of FLOT1 in T2DM liver may contribute to metabolic dyslipoproteinemia.

Efficacy of novel nano-hydroxyapatite/polyurethane composite scaffolds with silver phosphate particles in chronic osteomyelitis.

Recently, chronic osteomyelitis is still a challenging surgical problem. Unfortunately, the traditional clinical method using bone cement loaded antibiotics is restricted due to its non-biodegradability and limited release of antibiotics. Hydroxyapatite is a good adsorbent with good biocompatibility, an ideal bone repair material, and can avert the requirement for the secondary surgical procedure of removal. In this study, nano-hydroxyapatite combined with a polyurethane containing 3% silver (Ag/n-HA/PU) was synthesized, and investigated for its efficacy of treating chronic bone infection with bone defects. To clarify its silver ions release characteristics, the concentration of the Ag+ in the elution was analyzed every day after in vitro deionized water immersion. A chronic osteomyelitis of tibia in rabbit model was established, and 70 New Zealand rabbits were divided into 4 groups, including the blank control group, nano-hydroxyapatite combined with polyurethane (n-HA/PU) implant group, 3% Ag/n-HA/PU group and 10% Ag/n-HA/PU group after debridement. Routine blood tests, radiography, Micro-CT, and histological staining were conducted at 4 days, 3, 6 and 12 weeks post-treatment. The results showed that the released silver from the 3% Ag/n-HA/PU and 10% Ag/n-HA/PU exhibited an initial burst release and followed by a slow controlled release up to 39 days and 42 days respectively. A good repair of bone defects, an appropriate rate of degradation of scaffolds and no significant toxicity were observed in the 3% Ag/n-HA/PU group, indicating the advantages of this novel synthetic scaffold to be a potential option for the treatment of chronic osteomyelitis. A novel nano-composite, nano-hydroxyapatite combined with a polyurethane containing 3% silver (Ag/n-HA/PU) provide controlled release of Ag+, illustrated by its abilities of biodegradation, antimicrobial activity, and favorable repair of bone defects in the treatment of chronic osteomyelitis.

Efficacy of prophylactic probiotics in combination with antibiotics versus antibiotics alone for colorectal surgery: A meta-analysis of randomized controlled trials.

This meta-analysis aimed to determine whether prophylactic probiotics in combination with antibiotics are superior to antibiotics alone in the prevention of surgical site infection (SSI) after colorectal surgery. Fourteen trials involving 1524 participants were included. Compared with antibiotics alone, prophylactic probiotics in combination with antibiotics reduced the risk of SSI as well as other complications, shortened the cumulative duration of antibiotic therapy. Current evidence suggested that probiotics in combination with antibiotics could be recommended.

CT- versus MRI-based patient-specific instrumentation for total knee arthroplasty: A systematic review and meta-analysis.

BACKGROUND: To determine whether computed tomography (CT) or magnetic resonance imaging (MRI) is more suitable for the patient-specific instrumentation (PSI) systems for total knee arthroplasty (TKA). METHODS: PubMed, Embase, and the Cochrane Library were searched from inception to June 2016 for prospective comparative trials that compared CT- versus MRI-based PSI systems for TKA. Our predefined primary outcome was the outliers incidence of coronal overall limb alignment. RESULTS: Six studies with a total of 336 knees meeting the eligibility criteria, and four trials were included in the meta-analysis. Compared with MRI-based PSI systems, CT-based PSI systems were associated with a higher outliers incidence of coronal overall limb alignment (risk ratio: 1.67; 95% confidence interval (CI): 1.03-2.72; P = 0.04), more angular errors of coronal overall limb alignment (mean difference (MD): 1.01°; 95% CI: 0.47-1.56; P = 0.0003), and longer operation time (MD: 5.02 min; 95% CI: 1.26-8.79; P = 0.009). While no significant differences in the coronal/sagittal alignment of the femoral/tibial component outliers, the angular errors of coronal overall limb alignment, the angular errors of the femoral/tibial component in coronal plane, or incidence of change of implant size of the femoral/tibial component were observed. CONCLUSIONS: The current limited evidence suggests that MRI-based PSI systems exhibit higher accuracy for TKA regarding the coronal limb axis than CT-based PSI systems. However, well-designed studies comparing CT-versus MRI-based PSI systems for TKA are warrant to confirm these results before widespread use of this technique can be recommended.

PASPA: a web server for mRNA poly(A) site predictions in plants and algae.

MOTIVATION: Polyadenylation is an essential process during eukaryotic gene expression. Prediction of poly(A) sites helps to define the 3' end of genes, which is important for gene annotation and elucidating gene regulation mechanisms. However, due to limited knowledge of poly(A) signals, it is still challenging to predict poly(A) sites in plants and algae. PASPA is a web server for P: oly( A: ) S: ite prediction in P: lants and A: lgae, which integrates many in-house tools as add-ons to facilitate poly(A) site prediction, visualization and mining. This server can predict poly(A) sites for ten species, including seven previously poly(A) signal non-characterized species, with sensitivity and specificity in a range between 0.80 and 0.95.

Relationship between Annualized Case Volume and Mortality in Sepsis: A Dose-Response Meta-analysis.

BACKGROUND: The relationship between annualized case volume and mortality in patients with sepsis is not fully understood. The authors performed a dose-response meta-analysis to assess the effect of annualized case volume on mortality among patients with sepsis in the intensive care unit, emergency department, or hospital, hypothesizing that higher annualized case volume may lead to lower mortality. METHODS: The authors searched PubMed and Embase through July 2015 to identify observational studies that examined the relationship between annualized case volume and mortality in sepsis. The predefined outcome was mortality. Odds ratios with 95% CIs were pooled using a random-effects model. RESULTS: Ten studies involving 3,495,921 participants and 834,009 deaths were included. The pooled estimate suggested that annualized case volume was inversely associated with mortality (odds ratio, 0.76; 95% CI, 0.65 to 0.89; P = 0.001), with high heterogeneity (I = 96.6%). The relationship was consistent in most subgroup analyses and robust in sensitivity analysis. Dose-response analysis identified a nonlinear relationship between annualized case volume and mortality (P for nonlinearity less than 0.001). CONCLUSIONS: This meta-analysis confirmed the study hypothesis and provided strong evidence for an inverse and a nonlinear dose-response relationship between annualized case volume and mortality in patients with sepsis. Variations in cutoff values of category for annualized case volume across studies may mainly result in the overall heterogeneity. Future studies should uncover the mechanism of volume-mortality relationship and standardize the cutoff values of category for annualized case volume in patients with sepsis.