tRNA-derived fragments: Unveiling new roles and molecular mechanisms in cancer progression.

tRNA-derived fragments (tRFs) are novel small noncoding RNAs (sncRNAs) that range from approximately 14 to 50 nt. They are generated by the cleavage of mature tRNAs or precursor tRNAs (pre-tRNAs) at specific sites. Based on their origin and length, tRFs can be classified into three categories: (1) tRF-1 s; (2) tRF-3 s, tRF-5 s, and internal tRFs (i-tRFs); and (3) tRNA halves. They play important roles in stress response, signal transduction, and gene expression processes. Recent studies have identified differential expression of tRFs in various tumors. Aberrantly expressed tRFs have critical clinical value and show promise as new biomarkers for tumor diagnosis and prognosis and as therapeutic targets. tRFs regulate the malignant progression of tumors via various mechanisms, primarily including modulation of noncoding RNA biogenesis, global chromatin organization, gene expression regulation, modulation of protein translation, regulation of epigenetic modification, and alternative splicing regulation. In conclusion, tRF-mediated regulatory pathways could present new avenues for tumor treatment, and tRFs could serve as promising therapeutic targets for cancer therapy.

Genotypic and phenotypic characteristics of Streptococcus pneumoniae from community-acquired pneumonia patients and healthy asymptomatic participants in Sichuan province, China.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is the common cause of community-acquired pneumonia (CAP) and is also found in the upper respiratory tract of healthy people. Hence, the study aimed to compare the serotypes, virulence/pili genes, and antibiotic susceptibility of S. pneumoniae from healthy asymptomatic participants and CAP patients. METHODS: Streptococcus pneumoniae were retrospectively collected from health asymptomatic participants and CAP patients in Sichuan, China. The serotypes were tested by multiplex polymerase chain reaction (PCR) or Quellung reaction. Antibiotic susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S. pneumoniae was analyzed by multilocus sequence typing (MLST). Additionally, the presence of virulence/pili genes were detected using PCR. RESULTS: A total of 83 pneumococcal isolates were collected in the current study. Of these, 52 and 31 isolates were from healthy asymptomatic participants and CAP patients, respectively. Most of S. pneumoniae were resistant to erythromycin (ERY), clindamycin (CLI), tetracycline (TET) and trimethoprim-sulfamethoxazole (SXT). 90.4% isolates were classified as multidrug resistant (MDR). The predominant serotypes were 3, 19F and 19A in the CAP carriers, whereas 3, 6 and 19F were the main serotypes among the asymptomatic carriers. The overall coverage rates of pneumococcal conjugate vaccine (PCV) 10 and PCV13 serotypes were 34.9% and 66.3%, respectively. The predominant sequence types (STs) were ST271, ST320, and ST3397. There were significant differences in some resistance and virulence characteristics between CAP patients and asymptomatic carriers. Additionally, clonal complex (CC) 271 strains had higher percentage in resistance to cefuroxime (CXM) and cefotaxime (CEF), meropenem (MER) and cefepime (CFP), which mainly carried the rlrA and sipA genes. CONCLUSIONS: High coverage rate of PCV13 and high prevalence of MDR indicated the necessity to expand immunization with PCV13 and rationally use the antibiotics in Sichuan, China. Importantly, long-term surveillance should be conducted to assess effectiveness brought by vaccines. Our findings may supply new guidance for developing new pneumococcal vaccines.

CRISPR/Cas9 Mediated Deletion of the Uox Gene Generates a Mouse Model of Hyperuricemia with Multiple Complications.

Hyperuricemia is a common metabolic disorder with severe complications. We aimed to develop a mouse model for spontaneous hyperuricemia. Uox-/- mouse model was generated on C57BL/6J background by deleting exon 2-4 of Uox using the CRISPR/Cas9 system. The prototypic Uox -/-mice had 5.5-fold increased serum uric acid (1351.04±276.58µmol/L) as compared to the wild type mice (P<0.0001), but died by 4 weeks. After allopurinol (3ug/g) intervention, they all survived > 8 weeks. The serum uric acid was 612.55±146.98µmol/L in the 8-week-old allopurinol-rescued Uox -/-mice, which manifested multiple complications including severe renal insufficiency, hypertension, left ventricular remodeling and systolic dysfunction, aortic endothelial dysfunction, hepatic steatosis and elevated liver enzymes, as well as hyperglycemia and hypercholesteremia. The present Uox-/- mice developed spontaneous hyperuricemia complicated with urate nephropathy, cardiovascular disease and cardiometabolic disorders, and may provide a novel tool to study hyperuricemia associated early-onset cardiovascular disorders in human.

Anti-cancer Drug Anlotinib Promotes Autophagy and Apoptosis in Breast Cancer.

BACKGROUND: Anlotinib, a multi-target tyrosine kinase inhibitor, has significant anti-cancer effects on breast cancer (BC), lung cancer, colon cancer and ovarian cancer, but its mechanism has not been investigated in BC. METHODS: The cell viability and growth of human non-triple negative BC cell line MCF-7 and triple negative BC cell line MDA-MB-231 with the treatment of anlotinib were tested by Cell Counting Kit-8 (CCK-8) assay and Ki67 staining. The alteration of genes related to apoptosis and autophagy were investigated by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR), western blots and immunocytochemistry (ICC). Cell apoptosis was valued by TUNEL staining and flow cytometry. Further, mouse breast tumour cell lines AT-3 cells were subcutaneously injected into C57BL/6 mice, and the effect of anlotinib intragastrically on tumour growth in vivo was examined. RESULTS: We found that anlotinib suppressed the cell viability and depressed Ki67 staining in MCF-7 and MDA-MB-231 cell lines. Besides, the drug also enhanced cell autophagy and apoptosis of MCF-7 and MDA-MB-231 cell lines, which could be rescued by autophagy inhibitors wortmannin (wort) and 3-methyladenine (3-MA), and BECN1 knockdown. Furthermore, Akt/GSK-3α pathway was inactivated by anlotinib treatment, while rescued by wort, 3-MA and silencing of BECN1 in the MCF-7 or MDA-MB-231 cells. We also found that anlotinib inhibited implanted tumour growth of BC in syngeneic mice. CONCLUSIONS: Our study demonstrated that anlotinib inhibited breast cancer cell growth in vitro and in vivo. Anlotinib promoted cell apoptosis and inactivated Akt/GSK-3α pathway of BC cells by inducing cell autophagy. It indicated that anlotinib may be an effective new drug for BC treatment.

[Construction and expression of the prokaryotic expression vector of MTB cfpl0-esat6 fusion gene].

To begin with, we constructed cfp10-esat6 fusion gene and its prokaryotic expression vector and had it express in E. coli. By GeneSOEing techniques, a fusion gene was constructed by splicing cfpl0 gene and esat6 gene, and then was cloned into pGEX-4T-1 plasmid. Secondly, we constructed the prokaryotic expression recombinant plasmid pGcfp10-esat6. After identification with restriction enzyme analysis, PCR and nucleotide sequencing analysis, The E. coli BL21 containing the recombinant plasmid was induced by IPTG (Isopropy-beta-D-thiogalatoside). The fusion protein CFP10-ESAT6 with GST-tag about 42 kDa was expressed and purified with GST-fusion protein purification kit,The expression of cfp10-esat6 fusion gene was subsequently detected by SDS-polyacrylamine gel electrophoresis and Western-blot analysis. The sequence of cfp10 and esat6 in recombinant plasmid was consistent with that of GenBank report. The fusion protein existed in cytoplasm in soluble form and represented about 40% total bacterial protein of E. coil. The fusion protein was purified and the purity reached 90%. Its antigenicity was confirmed by Western-blotting. The prokaryotic expression vector (pGcfp1o-esat6) was constructed successfully, and the fusion protein CFP10-ESAT6 was obtained. This study provided an experimental basis for potential application of the recombinant CFP10-ESAT6 in the diagnosis of tuberculosis.

Molecular Typing of Pathogenic Leptospira Serogroup Icterohaemorrhagiae Strains Circulating in China during the Past 50 Years.

BACKGROUND: Leptospirosis is one of the most important neglected tropical infectious diseases worldwide. Icterohaemorrhagiae has been throughout recent history, and still is, the predominant serogroup of this pathogen in China. However, very little in detail is known about the serovars or genotypes of this serogroup. METHODOLOGY/PRINCIPAL FINDINGS: In this study, 120 epidemic strains from five geographically diverse regions in China collected over a 50 year period (1958~2008), and 8 international reference strains characterized by 16S rRNA sequencing and MLST analysis. 115, 11 and 2 strains were identified as L. interrogans, L. borgpetersenii, and L. kirschneri, respectively. 17 different STs were identified including 69 ST1 strains, 18 ST17, 18 ST128, 9 ST143 and 2 ST209. The remaining 12 strains belonged to 12 different STs. eBURST analysis demonstrated that, among the clonal complexes isolated (CCs), CC1 accounted for 73.3% (88/120) strains representing three STs: ST1, ST128 and ST98. ST1 was the most likely ancestral strain of this CC, followed by singleton CC17 (17/120) and CC143 (11/120). Further analysis of adding 116 serogroup Icterohaemorrhagiae strains in the MLST database and studies previously described using global eBURST analysis and MST dendrogram revealed relatively similar ST clustering patterns with five main CCs and 8 singletons among these 244 strains. CC17 was found to be the most prevalent clone of pathogenic Leptospira circulating worldwide. This is the first time, to our knowledge, that ST1 and ST17 strains were distributed among 4 distinct serovars, indicating a highly complicated relationship between serovars and STs. CONCLUSIONS/SIGNIFICANCE: Our studies demonstrated a high level of genetic diversity in the serogroup Icterohaemorrhagiae strains. Distinct from ST17 or ST37 circulating elsewhere, ST1 included in CC1, has over the past 50 years or so, proven to be the most prevalent ST of pathogenic leptospires isolated in China. Moreover, the complicated relationship between STs and serovars indicates an urgent need to develop an improved scheme for Leptospira serotyping.

[Preparation of recombinant Mycobacterium tuberculosis ESAT6-PPE68 fusion protein].

OBJECTIVE: To construct esat6-ppe68 fusion gene and its prokaryotic expression vector for expression in E. coli. METHODS: With GeneSOEing method, a fusion gene was constructed by splicing esat6 gene and ppe68 gene and cloned into pGEX-4T-1 plasmid to construct the recombinant prokaryotic expression plasmid pGesat6-ppe68. After identification with restriction enzyme analysis, PCR and nucleotide sequencing analysis of the plasmid, E. coli BL21 was transformed with the recombinant plasmid and induced with IPTG to obtain the expression of the fusion protein ESAT6-PPE68 with GST-tag (about 69 kD), which were purified with GST-fusion protein purification kit. The expression of esat6-ppe68 fusion gene was subsequently detected by SDS-PAGE and Western blot analysis. RESULTS: The sequence of esat6 and ppe68 in the recombinant plasmid was consistent with that in GenBank report. The fusion protein was detected in the cytoplasm in soluble form and represented approximately 40% of the total bacterial protein of E. coli. After purification, the purity of the fusion protein reached 90%, and its antigenicity was confirmed by Western blotting. CONCLUSION: The prokaryotic expression vector pGesat6-ppe68 has been constructed and the fusion protein ESAT6-PPE68 obtained successfully, which provides an experimental basis for potential application of the recombinant ESAT6-PPE68 in the diagnosis of tuberculosis.