Sex differences in the expression of lupus-associated miRNAs in splenocytes from lupus-prone NZB/W<Subscript>F1</Subscript> mice

Background

A majority of autoimmune diseases, including systemic lupus erythematosus (SLE), occur predominantly in females. Recent studies have identified specific dysregulated microRNAs (miRNAs) in both human and murine lupus, implying an important contribution of these miRNAs to lupus pathogenesis. However, to date, there is no study that examined sex differences in miRNA expression in immune cells as a plausible basis for sex differences in autoimmune disease. This study addresses this aspect in NZB/W_F1 mice, a classical murine lupus model with marked female bias, and further investigates estrogen regulation of lupus-associated miRNAs.

Methods

The Taqman miRNA assay system was used to quantify the miRNA expression in splenocytes from male and female NZB/W_F1 mice at 17–18, 23, and 30 weeks (wks) of age. To evaluate potential estrogen's effect on lupus-associated miRNAs, 6-wk-old NZB/W_F1 male mice were orchidectomized and surgically implanted with empty (placebo) or estrogen implants for 4 and 26 wks, respectively. To assess the lupus status in the NZB/W_F1 mice, serum anti-dsDNA autoantibody levels, proteinuria, and renal histological changes were determined.

Results

The sex differences in the expression of lupus-associated miRNAs, including the miR-182-96-183 cluster, miR-155, miR-31, miR-148a, miR-127, and miR-379, were markedly evident after the onset of lupus, especially at 30 wks of age when female NZB/W_F1 mice manifested moderate to severe lupus when compared to their male counterparts. Our limited data also suggested that estrogen treatment increased the expression of aforementioned lupus-associated miRNAs, with the exception of miR-155, in orchidectomized male NZB/W_F1 mice to a similar level in age-matched intact female NZB/W_F1 mice. It is noteworthy that orchiectomy, itself, did not affect the expression of lupus-associated miRNAs.

Conclusion

To our knowledge, this is the first study that demonstrated sex differences in the expression of lupus-associated miRNAs in splenocytes, especially in the context of autoimmunity. The increased expression of lupus-associated miRNA in female NZB/W_F1 mice and conceivably in estrogen-treated orchidectomized male NZB/W_F1 mice was associated with lupus manifestation. The notable increase of lupus-associated miRNAs in diseased, female NZB/W_F1 mice may be a result of both lupus manifestation and the female gender.

     

Comparative study of the cytotoxicity of the nanosized and microsized tellurium powders on HeLa cells

To compare the cytotoxicity on HeLa cells induced by nanosized and microsized tellurium powders, HeLa cells were exposed to different concentrations of tellurium powders (0, 50, 100, 150 and 200 μg/mL) for 12 h. In this study, detection of a series of biomarkers, including reactive oxygen species (ROS), glutathione (GSH), 8-hydroxy-2′-deoxyguanosine (8-OHdG), in addition to DNA and protein crosslink (DPC) and MTTassay, were conducted to evaluate the cytotoxicity. It is indicated that compared with the control group, there was no significant difference in the induced cytotoxicity at concentrations lower than 50 μg/mL for both nanosized and microsized tellurium powders. While there appears a significant difference in the induced cytotoxicity for nanosized tellurium powders when the concentration is higher than 100 μg/mL as well as for microsized tellurium powders when the concentration is higher than 200 μg/mL. Moreover, it is found that the cytotoxicity induced on HeLa cells exhibits a certain dose-effect relationship with the concentration of tellurium powders. A conclusion has been reached that the toxicity on HeLa cells can be induced by both nanosized and microsized tellurium powders, and the toxicity of the nanosized tellurium powders is significantly greater than the microsized one.     

Overexpressed MicroRNA-182 Promotes Proliferation and Invasion in Prostate Cancer PC-3 Cells by Down-Regulating N-myc Downstream Regulated Gene 1 (NDRG1)

MicroRNAs, non-coding 20–22 nucleotide single-stranded RNAs, result in translational repression or degradation and gene silencing of their target genes, and significantly contribute to the regulation of gene expression. In the current study, we report that miR-182 expression was significantly upregulated in prostate cancer tissues and four cell lines, compared to benign prostatic hyperplasia tissues and normal prostatic epithelial (RWPE-1) cells. Ectopic overexpression of miR-182 significantly promotes the proliferation, increases the invasion, promotes the G1/S cell cycle transition and reduces early apotosis of PC-3 cells, while suppression of miR-182 decreased the proliferation and invasion, inhibits the G1/S cell cycle transition and increase early apotosis of PC-3 cells. Additionally, we demonstrated that miR-182 could downregulate expression of NDRG1 by directly targeting the NDRG1 3′-untranslated region. In conclusion, our results suggest that miR-182 plays an important role in the proliferation of human prostate cancer cells by directly suppressing the tumor supressor gene NDRG1. We uncovered a new epigenetic regulation of NDRG1.     

田菁根际促生菌的筛选及其促生耐盐效果

【目的】为探究盐生植物田菁及其根际功能微生物改良盐碱地的效果,本研究从黄河三角洲盐碱区田菁根际土壤中分离促生菌,并明确其耐盐促生效果。【方法】采用选择培养方法从田菁根际土壤中分离固氮菌、解磷菌以及解钾菌,并进行16S rRNA分子生物学鉴定。之后对菌株的耐盐及促生特性进行测定,筛选性状优良菌株进行玉米促生作用研究。【结果】共分离得到105株根际促生菌,其中N102兼具多种促生特性且耐盐性达15%。田菁种子发芽试验表明,N102可显著提高田菁发芽率(47%,P0.05)、芽长(48.5%,P0.05)和根长(60%,P0.05);玉米盆栽试验结果表明,N102对盐胁迫下玉米的株高、根长、叶绿素含量、地上部干重以及根干重具有显著的促进作用。经系统发育分析,N102与Enterobacter soli ATCC BAA-2102 (NR117547)序列相似度为99.30%,鉴定属于Enterobacter属。【结论】菌株N102具有多种植物促生耐盐特性,具有开发成有效促进盐碱地作物生长的微生物肥的良好前景。     

Comparative genomic and protein sequence analyses of the chemotaxis system of Azorhizobium caulinodans北大核心CSCD

［Objective］ Azorhizobium caulinodans ORS571 can fix nitrogen not only as a free-living organism and an associative-symbiotic bacterium by colonizing the root surface of non-leguminous plants, but also as a symbiotic bacterium by interacting with leguminous plant Sesbania rostrata.Due to its ability to grow and fix nitrogen under three conditions, A.caulinodans uses sophisticated chemotaxis signal transduction systems to transform environmental cues into corresponding behavioral responses.Chemotaxis appears crucial for the growth of A.caulinodansin complicated environment and the construction of associative relationship with the plant.However, little is known about the chemotactic pathway of A.caulinodans.Thus, our study aimed to compare the chemotaxis-like genes of A.caulinodans with those of well-studied species.［Methods］ NCBI protein BLAST was used for searching sequence similarity with default parameter values against the genomes of A.caulinodans.HMMER3, based on Pfam database, was used for comparative analyses of methyl-accepting chemotaxis protein （MCP）.［Results］ There was a major chemotaxis cluster in A.caulinodans and the CheR methylated MCPs independently of pentapeptide motif.There were 43 MCP homologs containing diverse signal-sensing architectures in A.caulinodans.In addition,cytoplasmic domains of these MCPs were all composed of 38 heptad repeats.［Conclusion］ Despite the extremely high homology presented between the chemotactic system of A.caulinodans and those of well-studied species, A.caulinodans shows its own unique characteristics.The classification of these chemotactic pathways by comparative genomics enables us to better understand how A.caulinodansresponds to changes in environment via exquisite signal transductions in chemotaxis system.     

Characterization of two monoclonal antibodies, 38F10 and 44D11,against the major envelope fusion protein of Helicoverpa armigera nucleopolyhedrovirus

The envelope fusion protein F of baculoviruses is a class I viral fusion protein which play a significant role during virus entry into insect cells. F is initially synthesized as a precursor(F_0) and then cleaved into a disulfide-linked F_1 and F_2 subunits during the process of protein maturation and secretion. To facilitate further investigation into the structure and function of F protein during virus infection, monoclonal antibodies(mAbs) against the F_2 subunit of Helicoverpa armigera nucleopolyhedrovirus(HearNPV)(Ha F) were generated. Two kinds of mAbs were obtained according to their different recognition epitopes: one kind of mAbs, as represented by 38F10,recognizes amino acid(aa) 85 to 123 of F_2 and the other kind, represented by 44D11, recognizes aa148 to 173 of F_2. Western blot and immunofluorescence assay confirmed that both of the mAbs recognized the F protein expressed in HearNPV infected cells, however, only 44D11 could neutralize HearNPV infection. The results further showed that 44D11 may not interact with a receptor binding epitope, rather it was demonstrated to inhibit syncytium formation in cells expressing the Ha F protein. The results imply that the monoclonal antibody 44D11 recognizes a region within HaF_2 that may be involved in the F-mediated membrane fusion process.