Single‐cell dynamics of chromatin activity during cell lineage differentiation in Caenorhabditis elegans embryos

Elucidating the chromatin dynamics that orchestrate embryogenesis is a fundamental question in developmental biology. Here, we exploit position effects on expression as an indicator of chromatin activity and infer the chromatin activity landscape in every lineaged cell during Caenorhabditis elegans early embryogenesis. Systems‐level analyses reveal that chromatin activity distinguishes cellular states and correlates with fate patterning in the early embryos. As cell lineage unfolds, chromatin activity diversifies in a lineage‐dependent manner, with switch‐like changes accompanying anterior–posterior fate asymmetry and characteristic landscapes being established in different cell lineages. Upon tissue differentiation, cellular chromatin from distinct lineages converges according to tissue types but retains stable memories of lineage history, contributing to intra‐tissue cell heterogeneity. However, the chromatin landscapes of cells organized in a left–right symmetric pattern are predetermined to be analogous in early progenitors so as to pre‐set equivalent states. Finally, genome‐wide analysis identifies many regions exhibiting concordant chromatin activity changes that mediate the co‐regulation of functionally related genes during differentiation. Collectively, our study reveals the developmental and genomic dynamics of chromatin activity at the single‐cell level.     

Interleukin-1 receptor antagonist inhibits metastatic potential by down-regulating CXCL12/CXCR4 signaling axis in colorectal cancer

Wnt signaling plays key roles in cellular and physiological processes, including cell proliferation, differentiation and migration during development and tissue homeostasis in adults. This pathway can be defined as Wnt/β-catenin-dependent or β-catenin-independent or “non-canonical”, both signaling are involved in neurite and synapse development/maintenance. Porcupine (PORCN), an acylase that o-acylates Wnt ligands, a major modification in secretion and interaction with its receptors. We use Wnt-C59, a specific PORCN inhibitor, to block the secretion of endogenous Wnts in embryonic hippocampal neurons (DIV 4). Under these conditions, the activity of exogenous Wnt ligands on the complexity of the dendritic tree and axonal polarity were evaluated Cultured primary embryonic hippocampal neurons obtained from Sprague–Dawley rat fetuses (E18), were cultured until day in vitro (DIV) 4 (according to Banker´s protocol) and treated with Wnt-C59 for 24 h, Wnt ligands were added to the cultures on DIV 3 for 24 h. Dendritic arbors and neurites were analysis by fluorescence microscopy. Transfection with Lipofectamine 2000 on DIV 2 of plasmid expressing eGFP and KIF5-Cherry was carried out to evaluate neuronal polarity. Immunostaining was performed with MAP1B and Tau protein. Immunoblot analysis was carried out with Wnt3a, β-catenin and GSK-3β (p-Ser9). Quantitative analysis of dendrite morphology was carried out with ImageJ (NIH) software with Neuron J Plugin. We report, here, that Wnt-C59 treatment changed the morphology of the dendritic arbors and neurites of embryonic hippocampal neurons, with decreases β-catenin and Wnt3a and an apparent increase in GSK-3β (p-Ser9) levels. No effect was observed on axonal polarity. In sister cultures, addition of exogenous Wnt3a, 5a and 7a ligands rescued the changes in neuronal morphology. Wnt3a restored the length of neurites to near that of the control, but Wnt7a increased the neurite length beyond that of the control. Wnt5a also restored the length of neurites relative to Wnt concentrations. Results indicated that Wnt ligands, added exogenously, restored dendritic arbor complexity in embryonic hippocampal neurons, previously treated with a high affinity specific Porcupine inhibitor. We proposed that PORCN is an emerging molecular target of interest in the search for preclinical options to study and treat Wnt-related diseases.     

The detrimental effect of iron on OA chondrocytes: Importance of pro-inflammatory cytokines induced iron influx and oxidative stress

Iron overload is common in elderly people which is implicated in the disease progression of osteoarthritis (OA), however, how iron homeostasis is regulated during the onset and progression of OA and how it contributes to the pathological transition of articular chondrocytes remain unknown. In the present study, we developed an in vitro approach to investigate the roles of iron homeostasis and iron overload mediated oxidative stress in chondrocytes under an inflammatory environment. We found that pro-inflammatory cytokines could disrupt chondrocytes iron homeostasis via upregulating iron influx transporter TfR1 and downregulating iron efflux transporter FPN, thus leading to chondrocytes iron overload. Iron overload would promote the expression of chondrocytes catabolic markers, MMP3 and MMP13 expression. In addition, we found that oxidative stress and mitochondrial dysfunction played important roles in iron overload-induced cartilage degeneration, reducing iron concentration using iron chelator or antioxidant drugs could inhibit iron overload-induced OA-related catabolic markers and mitochondrial dysfunction. Our results suggest that pro-inflammatory cytokines could disrupt chondrocytes iron homeostasis and promote iron influx, iron overload-induced oxidative stress and mitochondrial dysfunction play important roles in iron overload-induced cartilage degeneration.     

New Phenylpropanoid Glycosides from Illicium majus and Their Radical Scavenging Activities

Chemical investigation of the ethanol extract of the branch and leaves of Illicium majus resulted in the isolation of four new phenylpropanoid glycosides ( 1 – 4 ) and one new phenolic glycoside ( 9 ), along with 13 known ones. Spectroscopic techniques were used to elucidate the structures of the new isolates such as 3-[(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydro-1-benzofuran-5-yl]propyl β-D-glucopyranoside ( 1 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( 2 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-xylopyranoside ( 3 ), 3-[(2R,3S)-3-({[2-O-(4-O-acetyl-α-L-rhamnopyranosyl)-β-D-xylopyranosyl]oxy}methyl)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-2,3-dihydro-1-benzofuran-5-yl]propyl acetate ( 4 ), and 4-(2-hydroxyethyl)phenyl 3-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 9 ). Free radical scavenging activities of the isolates were elucidated through the DPPH assay method. The most active compounds, 1-O-caffeoyl-β-D-glucopyranose ( 17 ) and soulieana acid 1 ( 18 ), exhibited moderate radical scavenging activities (IC₅₀=37.7±4.4 μM and IC₅₀=97.2±3.4 μM, respectively). The antibacterial activities of the isolates against Staphylococcus aureus and Escherichia coli were also assessed, and no activity was shown at the measured concentration (<32 μg/mL).     

Possible pharmaceutical applications can be developed from naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids

Naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids (PIAs and PQAs) are two small groups of herbal metabolites sharing a similar pentacyclic structure with a highly oxygenated phenanthrene moiety fused with a saturated or an unsaturated N-heterocycle (indolizidine/quinolizidine moieties). Natural PIAs and PQAs only could be obtained from finite plant families (such as Asclepiadaceae, Lauraceae and Urticaceae families, etc.). Up to date, more than one hundred natural PIAs, while only nine natural PQAs had been described. PIA and PQA analogues have been applied to the development of potent anticancer agents all along because of their excellent cytotoxic activity. However, in the last two decades, other great biological properties, such as anti-inflammatory and antiviral activities were revealed successively by different pharmacological assays. Especially because of their potent antiviral activity against coronavirus (TGEV, SARS CoV and MHV) and tobacco mosaic virus, PIA and PQA analogues have attracted much pharmaceutical attention again, some of them have been used to present interesting targets for total or semi synthesis, and structure–activity relationship (SAR) study for the development of antiviral agents. In this review, natural PIA and PQA analogues obtained in the last two decades with their herbal origins, key spectroscopic characteristics for structural identification, biological activity with possible SARs and application prospects were systematically summarized. We hope this paper can stimulate further investigations on PIA and PQA analogues as an important source for potential drug discovery.

     

Establishment of an efficient shoot regeneration system in vitro in Brassica rapa

In Vitro Cellular & Developmental Biology - Plant - To improve the genetic transformation system for Brassica rapa L., we established a high-efficiency shoot regeneration protocol. A double...     

Restoration of circPSMC3 sensitizes gefitinib-resistant esophageal squamous cell carcinoma cells to gefitinib by regulating miR-10a-5p/PTEN axis

Circular RNAs (circRNAs) has been shown to play an important role in the progression of various cancers. However, the function and underlying mechanisms of circRNAs affecting chemotherapy resistance in esophageal squamous cell carcinoma (ESCC) remain largely unknown. In this study, we used gefitinib-resistant (GR) ESCC cells to investigate the function of circPSMC3 and clarify the underlying mechanism in chemotherapy resistance in ESCC. The results suggested that circPSMC3 expression was downregulated, but miR-10a-5p was upregulated in ESCC tissues and cells, as well as in GR ESCC cells. CircPSMC3 overexpression increased the sensitivity of ESCC cells to gefitinib, as indicated by reduced half maximal inhibitory concentration value, increased apoptosis rate and cleaved caspase-3 protein expression. CircPSMC3 directly interacted with miR-10a-5p and inhibited the expression of miR-10a-5p. Phosphatase and tensin homolog (PTEN) was a direct target of miR-10a-5p and circPSMC3 promoted PTEN expression via decreasing miR-10a-5p level. Moreover, the effect of circPSMC3 on resistance of GR ESCC cells to gefitinib was remarkably reduced by restoration of miR-10a-5p and downregultion of PTEN. Taken together, these observations suggested that upregulation of circPSMC3 overcame resistance of GR ESCC cells to gefitinib by modulating the miR-10a-5p/PTEN axis, which provide a new therapeutic strategy for overcoming gefitinib resistance in ESCC.