Summary Fleshy fruits are classically divided into climacteric and nonclimacteric types. It has long been thought that the ripening of climacteric and nonclimacteric fruits is regulated by ethylene and abscisic acid (ABA), respectively. Here, we report that sucrose functions as a signal in the ripening of strawberry (Fragaria × ananassa), a nonclimacteric fruit. Pharmacological experiments, as well as gain‐ and loss‐of‐function studies, were performed to demonstrate the critical role of sucrose in the regulation of fruit ripening. Fruit growth and development were closely correlated with a change in sucrose content. Exogenous sucrose and its nonmetabolizable analog, turanose, induced ABA accumulation in fruit and accelerated dramatically fruit ripening. A set of sucrose transporters, FaSUT1–7, was identified and characterized, among which FaSUT1 was found to be a major component responsible for sucrose accumulation during fruit development. RNA interference‐induced silencing of FaSUT1 led to a decrease in both sucrose and ABA content, and arrested fruit ripening. By contrast, overexpression of FaSUT1 led to an increase in both sucrose and ABA content, and accelerated fruit ripening. In conclusion, this study demonstrates that sucrose is an important signal in the regulation of strawberry fruit ripening.

Bone is a dynamic organ continuously undergoing shaping, repairing and remodeling. The homeostasis of bone is maintained by the balance between osteoblastic bone formation and osteoclastic bone resorption. Osteoclasts (OCs) are specialized multinucleated cells derived from hematopoietic stem cells (HSCs) or monocytes/macrophage progenitor cells. There are different stages during osteoclastogenesis, and one of the most important steps to form functional osteoclasts is realized by cell-cell fusion. In our study, microarray was performed to detect the expression profiles of lncRNA, mRNA, circRNA and miRNA at different stages during osteoclastogenesis of RAW264.7 cells. Often changed RNAs were selected and clustered among the four groups with Venn analysis. The results revealed that expressions of 518 lncRNAs, 207 mRNAs, 24 circRNAs and 37 miRNAs were often altered at each stage during OC differentiation. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway analysis were performed to predict the functions of differentially expressed lncRNAs and co-expressed potential targeting genes. Co-expression networks of lncRNA-mRNA and circRNA-miRNA were constructed based on the correlation analysis between the differentially expressed RNAs. The present study provided a systematic perspective on the potential function of non-coding RNAs (ncRNAs) during osteoclastogenesis.

At sites of chronic inflammation, epithelial cells are exposed to high levels of reactive oxygen species and undergo cancer-associated DNA methylation changes, suggesting that inflammation may initiate epigenetic alterations. Previously, we demonstrated that oxidative damage causes epigenetic silencing proteins to become part of a large complex that is localized to GC-rich regions of the genome, including promoter CpG islands that are epigenetically silenced in cancer. However, whether these proteins were recruited directly to damaged DNA or during the DNA repair process was unknown. Here we demonstrate that the mismatch repair protein heterodimer MSH2-MSH6 participates in the oxidative damage-induced recruitment of DNA methyltransferase 1 (DNMT1) to chromatin. Hydrogen peroxide treatment induces the interaction of MSH2-MSH6 with DNMT1, suggesting that the recruitment is through a protein-protein interaction. Importantly, the reduction in transcription for genes with CpG island-containing promoters caused by oxidative damage is abrogated by knockdown of MSH6 and/or DNMT1. Our findings provide evidence that the role of DNMT1 at sites of oxidative damage is to reduce transcription, potentially preventing transcription from interfering with the repair process. This study uniquely brings together several factors that are known to contribute to colon cancer, namely inflammation, mismatch repair proteins, and epigenetic changes.

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Background & Aims Epithelial regeneration is essential for homeostasis and repair of the mucosal barrier. In the context of infectious and immune-mediated intestinal disease, interleukin (IL) 22 is thought to augment these processes. We sought to define the mechanisms by which IL22 promotes mucosal healing . Methods Intestinal stem cell cultures and mice were treated with recombinant IL22. Cell proliferation, death, and differentiation were assessed in vitro and in vivo by morphometric analysis, quantitative reverse transcriptase polymerase chain reaction, and immunohistochemistry. Results IL22 increased the size and number of proliferating cells within enteroids but decreased the total number of enteroids. Enteroid size increases required IL22-dependent up-regulation of the tight junction cation and water channel claudin-2, indicating that enteroid enlargement reflected paracellular flux–induced swelling. However, claudin-2 did not contribute to IL22-dependent enteroid loss, depletion of Lgr5 + stem cells, or increased epithelial proliferation. IL22 induced stem cell apoptosis but, conversely, enhanced proliferation within and expanded numbers of transit-amplifying cells. These changes were associated with reduced wnt and notch signaling, both in vitro and in vivo, as well as skewing of epithelial differentiation, with increases in Paneth cells and reduced numbers of enteroendocrine cells. Conclusions IL22 promotes transit-amplifying cell proliferation but reduces Lgr5 + stem cell survival by inhibiting notch and wnt signaling. IL22 can therefore promote or inhibit mucosal repair, depending on whether effects on transit-amplifying or stem cells predominate. These data may explain why mucosal healing is difficult to achieve in some inflammatory bowel disease patients despite markedly elevated IL22 production.

In this study, for the first time we discovered that the M1/M2 macrophage phenotype ratio is increased in bone marrow of ovariectomized (OVX) osteoporotic C57BL/6 mice. Considering estrogen is the main variable, we assumed that estrogen participated in this alteration. To determine whether and how estrogen contributes to the change of the M1/M2 ratio, we first isolated bone marrow macrophages (BMMs) from mice femur and stimulated the cells with lipopolysaccharide (LPS)/interferon γ (IFN-γ) for M1 polarization and interleukin 4 (IL-4)/IL-13 for M2 polarization. M1 and M2 macrophages were then exposed to RANKL stimulation, we found that M2 macrophage but not M1 macrophage differentiated into functional osteoclast leading to increased M1/M2 ratio. Intriguingly, 17β-estradiol (E2) pretreatment prevented osteoclastogenesis from M2 macrophages. By constructing shRNA lentivirus interfering the expression of different estrogen receptors in M2 macrophages, we found that estrogen protects M2 macrophage from receptor activator of nuclear factor κB ligand (RANKL) stimulation selectively through estrogen receptor α (ERα) and the downstream blockage of NF-κB p65 nuclear translocation. Animal studies showed that ERα selective agonist 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT) was able to replicate the therapeutic effects of E2 in treating osteoporotic OVX mice. Together, our findings reveal that estrogen deficiency-mediated M2 macrophage osteoclastogenesis leads to increased M1/M2 ratio in OVX mice. Reducing the M1/M2 ratio is a potential therapeutic target in treating postmenopausal osteoporosis. © 2017 American Society for Bone and Mineral Research.

A variety of osteolytic factors have been identified from breast cancer cells leading to osteolysis, but less is known about which factor plays an essential role in the initiation process prior to the overt vicious osteolytic cycle. Here, we present in vitro and in vivo evidences to clarify the role of interleukin-11 (IL-11) as an essential contributor to breast cancer bone metastasis mediated osteolysis. Animal studies showed that bone specific metastatic BoM-1833 cells induce earlier onset of osteolysis and faster tumor growth compared with MCF7 and parental MDA-MB-231 cells in BALB/c-nu/nu nude mice. IL-11 was further screened and identified as the indispensable factor secreted by BoM-1833 cells inducing osteoclastogenesis independently of receptor activator of nuclear factor κB ligand (RANKL). Mechanistic investigation revealed that the JAK1/STAT3 signaling pathway as a downstream effector of IL-11, STAT3 activation further induces the expression of c-Myc, a necessary factor required for osteoclastogenesis. By inhibiting STAT3 phosphorylation, AG-490 was shown effective in reducing osteolysis and tumor growth in the metastatic niche. Overall, our results revealed the essential role and the underlying molecular mechanism of IL-11 in breast cancer bone metastasis mediated osteolysis. STAT3 targeting through AG-490 is a potential therapeutic strategy for mitigating osteolysis and tumor growth of bone metastatic breast cancer.

BackgroundThe objective of this study was to characterize the oral microflora profile of primary Sjögren’s syndrome (pSS) patients, thereby revealing the connection between oral bacterial composition and dental caries, and to identify the “core microbiome” in the oral cavities of pSS patients and systemic healthy individuals by using a high-throughput sequencing technique.MethodsTwenty-two pSS patients and 23 healthy controls were enrolled in this study. Their clinical data and oral rinse samples were collected. The V3–V4 hypervariable regions of the bacterial 16S rRNA gene of samples were amplified and analyzed by high-throughput sequencing on the Illumina Miseq PE300 platform.ResultsBoth two groups were age- and sex-matched. There were significantly higher decayed, missing and filled teeth (DMFT) and decayed, missing and filled surfaces (DMFS) in the pSS group than in the control group (p < 0.01). Alpha diversity was depleted in pSS patients, compared with healthy controls (p < 0.01), while beta diversity between the two groups was not significantly different. Seven discriminative genera (LDA > 4) were found between the two groups in LEfSe (LDA Effect Size) analysis. The relative abundance of Veillonella in pSS patients was fourfold higher, while Actinomyces, Haemophilus, Neisseria, Rothia, Porphyromonas and Peptostreptococcus were significantly lower in pSS patients than in healthy controls. However, the correlation between Veillonella and DMFT/DMFS was not significant (p > 0.05). In Venn diagram analysis, nine genera shared by all samples of two groups, which comprised 71.88% and 67.64% in pSS patients and controls, respectively.DiscussionThese findings indicate a microbial dysbiosis in pSS patients; notably, Veillonella might be recognized as a biomarker in pSS patients. The core microbiome in pSS patients was similar to the systemic healthy population. These provide insight regarding advanced microbial prevention and treatment of severe dental caries in pSS patients. This study also provides basic data regarding microbiology in pSS.