Pulmonary toxicity and RNA sequencing analyses of mouse in response to exposure to cellulose nanofibrils.

OBJECTIVE: The growing applications of nanocelluloses in the fields of advanced nanocomposites, electronics, and medical devices necessitate investigation of their potential adverse effects on human health. The lungs are the primary and the most important route for the entry of nanocelluloses into the human body in occupational settings. However, data on the pulmonary toxicity of cellulose nanofibrils (CNFs) and its molecular mechanism are limited. This study investigated the pulmonary toxicity of CNFs and its genomic expression using the RNA sequencing approach. MATERIALS AND METHODS: Female C57BL/6 mice were administered CNFs at 50 µg/mouse by oropharyngeal aspiration. Samples were collected at 3 and 14 days after exposure to CNFs (DAEC). RESULTS: At three DAEC, the microscopic sections of lungs revealed a significant inflammatory response. In terms of gene expression alterations, 94 genes were up-regulated, and 107 genes were down-regulated. Most of these differentially expressed genes were involved in the inflammatory and immune responses, including chemokines, NK cells, killer cell lectin-like receptors, CD antigens, T cell-specific GTPases, immunity-related GTPase family M members, and interferon-induced proteins encoding genes. However, only 9 and 26 genes at 14 DAEC were significantly up- and down-regulated, respectively. CONCLUSIONS: The pathological analysis of lung sections and the analysis of sequencing data suggested that the homeostasis of mice lungs was restored at 14 DAEC. The findings of this study provide insights into the pulmonary toxicity, and underlying toxicological mechanisms, caused by exposure to CNFs, and are useful for the assessment of the potential toxicity of nanocelluloses.

Long noncoding RNAs sustain high expression levels of exogenous octamer-binding protein 4 by sponging regulatory microRNAs during cellular reprogramming.

Long noncoding RNAs (lncRNAs) modulate gene expression as competing endogenous RNAs (ceRNAs) that sponge regulatory microRNAs (miRNAs). During cellular reprogramming, genes associated with pluripotency establishment need to be up-regulated, and developmental genes need to be silenced. However, how ceRNAs control cellular reprogramming still awaits full elucidation. Here, we used doxycycline-inducible expression of the four transcription factors octamer-binding protein 4 (OCT4), SRY-box 2 (SOX2), Krüppel-like factor 4 (KLF4), and proto-oncogene c-Myc (c-Myc) to generate induced pluripotent stem cells (iPSCs) from mouse embryonic fibroblasts (MEFs). Using RNA-Seq and bioinformatics approaches, we found that the expression levels of miRNAs from MEFs remain high from day 0 to 6 after the doxycycline induction. Many genes targeted by these miRNAs were up-regulated, and long intergenic noncoding RNAs (lincRNAs) and circular RNAs (circRNAs), which have complementary binding sites to these miRNAs, were highly expressed, indicating lincRNAs and circRNAs may function as ceRNAs. Intriguingly, knockdown of the linc/circRNAs that sponge the miRNAs, which target OCT4 down-regulated exogenous OCT4, decreased reprogramming efficiency, and resulted in low-grade iPSCs. Our results suggest that the ceRNA network plays an important role in cellular reprogramming.

Molecular cloning of allelopathy related genes and their relation to HHO in Eupatorium adenophorum.

In this study, conserved sequence regions of HMGR, DXR, and CHS (encoding 3-hydroxy-3-methylglutaryl-CoA reductase, 1-deoxyxylulose-5-phosphate reductoisomerase and chalcone synthase, respectively) were amplified by reverse transcriptase (RT)-PCR from Eupatorium adenophorum. Quantitative real-time PCR showed that the expression of CHS was related to the level of HHO, an allelochemical isolated from E. adenophorum. Semi-quantitative RT-PCR showed that there was no significant difference in expression of genes among three different tissues, except for CHS. Southern blotting indicated that at least three CHS genes are present in the E. adenophorum genome. A full-length cDNA from CHS genes (named EaCHS1, GenBank ID: FJ913888) was cloned. The 1,455 bp cDNA contained an open reading frame (1,206 bp) encoding a protein of 401 amino acids. Preliminary bioinformatics analysis of EaCHS1 revealed that EaCHS1 was a member of CHS family, the subcellular localization predicted that EaCHS1 was a cytoplasmic protein. To the best of our knowledge, this is the first report of conserved sequences of these genes and of a full-length EaCHS1 gene in E. adenophorum. The results indicated that CHS gene is related to allelopathy of E. adenophorum.