Estimation of hepatitis B-positive rates in Chinese blood donors by combining predonation and postdonation screening results.

BACKGROUND: Chinese blood centers use Hepatitis B surface antigen (HBsAg) rapid test (RT) in pre-donation and two rounds of screening with different enzyme-linked immunosorbent assays in post-donation. Nucleic acid testing (NAT) on screening non-reactive (SC-) donations has been gradually implemented since 2010. Yet RT+ and SC-/NAT+ donors are seldom included in hepatitis B virus (HBV) positive rate estimates in Chinese blood donors. METHODS: We performed HBsAg neutralization test (NT) on whole blood (WB) with pre-donation RT+ results and post-donation screening reactive (SC+) samples from Mianyang and Chongqing in 2015. The annual totals of pre- and post-donation NT+ donors were combined with the annual totals of SC-/NAT+ donors to derive the estimated HBV positive rates. RESULT: In Mianyang and Chongqing, 59.4% and 68.2% of RT+ donors in Jan-Aug 2015 contributed for NT, 95.5% and 97.2% of which were NT+ respectively. In 2015, 422 and 667 donors from Mianyang and Chongqing respectively were HBsAg RT+, yielding estimated 403 and 648 pre-donation RT+/NT+ deferrals. 411 and 668 post-donation SC+ samples were NT tested from Mianyang and Chongqing, of which 249 and 323 were NT+ respectively. An estimated 63 donors in Mianyang and 88 donors in Chongqing were SC-/NAT+. The estimated HBV confirmed positive rate in blood donors are 1.59% in Mianyang and 1.01% in Chongqing. CONCLUSION: Pre-donation HBsAg RT effectively intercepts donations from HBV infected donors. Using NT confirmatory results from RT+, SC+ and SC-/NAT+ donors, this study provides a model for more accurate estimation for HBV positive rates in China.

Metagenomics in pooled plasma, with identification of potential emerging infectious pathogens.

BACKGROUND: Many emerging infectious pathogens are well known for existing in healthy blood donors and could be transmitted via blood transfusion or plasma derivatives usage. Therefore, there is an urgent need to discover the pathogens in qualified blood donation to avoid potential threats to blood safety. STUDY DESIGN AND METHODS: The objective of this study was to investigate the microbiome that existed in pooled plasma from different manufacturers in Chengdu and Guiyang. Random polymerase chain reaction, large-scale clone sequencing, and bioinformatics were used to investigate the metagenomics and microbiome structure of pooled plasma. Among detected microbiomes, potential pathogens were subsequently identified. RESULT: After host DNA cleaning, 551 clones were classified as bacteria; 88 clones were classified as viruses, and four clones were considered to be parasites, respectively. Thirteen kinds of bacteria and two kinds of parasites that might potentially threaten blood safety were identified along with six kinds of nonpathogenic viruses. The infection status of one identified pathogen Coxiella burnetii was evaluated in 1638 plasma samples. The reactive rate of immunoglobulin (Ig)G1 was 1.10% (18/1638), the reactive rate of IgG2 was 0.85% (14/1638), and the reactive rate of IgM was 0.98% (16/1638). CONCLUSION: Some pathogens that were already considered as threats to blood safety were discovered in those pooled plasma such as C. burnetii, Orientia tsutsugamushi, and Plasmodium sp. As a result, we should initiate some specific tests in the endemic area on plasma donors to enhance the blood safety in China.

Capsid structure of bacteriophage ΦKZ provides insights into assembly and stabilization of jumbo phages.

Jumbo phages are a group of tailed bacteriophages with large genomes and capsids. As a prototype of jumbo phage, ΦKZ infects Pseudomonas aeruginosa, a multi-drug-resistant (MDR) opportunistic pathogen leading to acute or chronic infection in immunocompromised individuals. It holds potential to be used as an antimicrobial agent and as a model for uncovering basic phage biology. Although previous low-resolution structural studies have indicated that jumbo phages may have more complicated capsid structures than smaller phages such as HK97, the detailed structures and the assembly mechanism of their capsids remain largely unknown. Here, we report a 3.5-Å-resolution cryo-EM structure of the ΦKZ capsid. The structure unveiled ten minor capsid proteins, with some decorating the outer surface of the capsid and the others forming a complex network attached to the capsid's inner surface. This network seems to play roles in driving capsid assembly and capsid stabilization. Similar mechanisms of capsid assembly and stabilization are probably employed by many other jumbo viruses.

MicroRNA-449 targets histone deacetylase 1 to regulate the proliferation, invasion, and apoptosis of synovial fibroblasts in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic joint disease. The study aimed to explore the effects of microRNA (miR)-449 and histone deacetylase 1 (HDAC1) on the proliferation, invasion, and apoptosis of synovial fibroblasts in rheumatoid arthritis. METHODS: Synovial tissue was collected from 20 patients with RA and 20 patients with osteoarthritis (OA) who underwent joint replacement surgery. RA synovial fibroblasts (RASFs) and OA synovial fibroblasts (OASFs) were isolated and cultured. Real-time quantitative PCR was used to detect the expression levels of miR-449 and HDAC1 in synovial tissues and cells. Western blot was performed to detect the cellular expression levels of HDAC1 protein, and apoptosis and invasion-related proteins. The proliferation, invasion, and apoptosis of RASFs were detected by MTT assay, Transwell assay, and flow cytometry. The dual-luciferase reporter gene was used to test the targeting relationship between inflammatory miR-449 and HDAC1. RESULTS: Compared with normal synovial tissue and OASFs, the levels of HDAC1 messenger RNA in RA synovial tissue and RASF cells were significantly increased (P<0.01), while the expression levels of miR-449 were significantly decreased (P<0.01). The dual-luciferase reporter gene experiment confirmed that miR-449 could specifically bind to the 3' untranslated region of HDAC1 to inhibit its luciferase activity (P<0.05). HDAC1 inhibition or miR-449 overexpression significantly inhibited the proliferation and invasion of RASFs (P<0.001), while inducing their apoptosis (P<0.001). HDAC1 overexpression reversed the biological effects of miR-449 on RASFs (P<0.001). CONCLUSIONS: miR-449 inhibits the proliferation and invasion of RASFs and induces their apoptosis by targeting HDAC1, thereby exerting a protective effect against RA.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) inhibition modulates bone loss and matrix metalloproteinase expression levels in collagen-induced rheumatoid arthritis rat.

BACKGROUND: Rheumatoid arthritis (RA) is a main characterized by persistent synovitis, systemic inflammation, and autoantibodies. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase and is a crucial cytoplasm signal adaptor that can regulate critical biological processes. This research aims to explore the function of TRAF6 on bone loss and matrix metalloproteinase (MMP) expression in collagen-induced RA rats. METHODS: The RA model in rats (Sprague Dawley rat, 5-6 weeks old, weight 246.88±8.31 g) was set up via using collagen-induced RA. The shRNA-TRAF6 knockdown efficiency was tested using real-time reverse transcription-polymerase chain reaction (qRT-PCR) and western blot, respectively. The rats were divided into four groups: the control group, RA group, RA + shRNA-NC group, and RA + TRAF6-shRNA group. The tartrate-resistant acidic phosphatase (TRAP), hematoxylin and eosin (H&E), and Saffron O staining were employed to test the bone injury. The mRNA and protein expressive of Osteoclast-associated receptor (OSCAR), TRAP, Osterix (Osx), Collagen type I alpha 1 (COL1A1), Distal-less homeobox2 (Dlx2), tissue inhibitor of metalloproteinase (TIMP), matrix metalloproteinase-1(MMP-1), Cyclooxygenase 2 (COX2) and qRT-PCR performed MMP-13 and western blot, respectively. RESULTS: The mRNA and protein expression levels of TRAF6 were down-regulated in the RA + TRAF6- shRNA group. After the levels of TRAF6 were inhibited, the levels of bone volume/total volume (BV/TV), trabecular bone thickness (Tb.Th), and trabecular bone number (Tb.N) were increased, while the levels of trabecular bone space (Tb.Sp), Osteocalcin and ALP were deceased. The mRNA and protein expression levels of OSCAR, TRAP, MMP-1, COX2, and MMP-13 were reduced obviously in the RA + TRAF6- shRNA group compared with the RA + shRNA-NC group, while the levels of TIMP-1, OSX, CoL1A1, and DLx2 were enhanced obviously. CONCLUSIONS: Inhibition of TRAF6 reduces bone loss and MMP expression levels in collagen-induced RA rat, and supplies an alternative treatment method in RA.