PICKLE and HISTONE DEACETYLASE6 coordinately regulate genes and transposable elements in Arabidopsis.

Chromatin dynamics play essential roles in transcriptional regulation. The chromodomain helicase DNA-binding domain 3 (CHD3) chromatin remodeler PICKLE (PKL) and HISTONE DEACETYLASE6 (HDA6) are required for transcriptional gene silencing, but their coordinated function in gene repression requires further study. Through a genetic suppressor screen, we found that a point mutation at PKL could partially restore the developmental defects of a weak Polycomb repressive complex 1 (PRC1) mutant (ring1a-2 ring1b-3), in which RING1A expression is suppressed by a T-DNA insertion at the promoter. Compared to ring1a-2 ring1b-3, the expression of RING1A is increased, nucleosome occupancy is reduced, and the histone 3 lysine 9 acetylation (H3K9ac) level is increased at the RING1A locus in the pkl ring1a-2 ring1b-3 triple mutant. HDA6 interacts with PKL and represses RING1A expression similarly to PKL genetically and molecularly in the ring1a-2 ring1b-3 background. Furthermore, we show that PKL and HDA6 suppress the expression of a set of genes and transposable elements (TEs) by increasing nucleosome density and reducing H3K9ac. Genome-wide analysis indicated they possibly coordinately maintain DNA methylation as well. Our findings suggest that PKL and HDA6 function together to reduce H3K9ac and increase nucleosome occupancy, thereby facilitating gene/TE regulation in Arabidopsis (Arabidopsis thaliana).

Polycomb proteins RING1A/B promote H2A monoubiquitination to regulate female gametophyte development in Arabidopsis.

A functional female gametophyte is the basis of successful sexual reproduction in flowering plants. During female gametophyte development, the megaspore mother cell (MMC), differentiated from a single subepidermal somatic cell in the nucellus, undergoes meiosis to produce four megaspores; only the one at the chalazal end, referred to as functional megaspore (FM), undergoes three rounds of mitosis and develops into a mature embryo sac. Here, we reported that RING1A and RING1B (RING1A/B), two functionally redundant Polycomb proteins in Arabidopsis, are critical for female gametophyte development. The mutations of RING1A/B resulted in defects in MMC and FM's specification and subsequent mitosis of FM, thereby leading to aborted ovules. Gene expression analysis revealed several genes essential for female gametophyte development, including Argonaute (AGO) family genes and critical transcription factors, were ectopically expressed in ring1a ring1b. Furthermore, RING1A/B bound some of these genes to promote H2A monoubiquitination (H2Aub) deposition. Together, RING1A/B promote H2Aub modification at genes essential for female gametophyte development, suppressing their expression to ensure the progression of female gametophyte development.

The Histone Variant H3.3 Is Required for Plant Growth and Fertility in Arabidopsis.

Histones are the core components of the eukaryote chromosome, and have been implicated in transcriptional gene regulation. There are three major isoforms of histone H3 in Arabidopsis. Studies have shown that the H3.3 variant is pivotal in modulating nucleosome structure and gene transcription. However, the function of H3.3 during development remains to be further investigated in plants. In this study, we disrupted all three H3.3 genes in Arabidopsis. Two triple mutants, h3.3cr-4 and h3.3cr-5, were created by the CRISPR/Cas9 system. The mutant plants displayed smaller rosettes and decreased fertility. The stunted growth of h3.3cr-4 may result from reduced expression of cell cycle regulators. The shorter stamen filaments, but not the fertile ability of the gametophytes, resulted in reduced fertility of h3.3cr-4. The transcriptome analysis suggested that the reduced filament elongation of h3.3cr-4 was probably caused by the ectopic expression of several JASMONATE-ZIM DOMAIN (JAZ) genes, which are the key repressors of the signaling pathway of the phytohormone jasmonic acid (JA). These observations suggest that the histone variant H3.3 promotes plant growth, including rosette growth and filament elongation.

Ultrasonic treatment enhanced the binding capacity of volatile aldehydes and pearl mussel (Hyriopsis cumingii) muscle: Investigation of underlying mechanisms.

This study was aim to investigate the influencing mechanism of ultrasonic treatment on the interaction between volatile aldehydes and myosin. The results showed that when the mass concentration ratio of myosin to heptanal/hexanal was 1:0.3, ultrasonic treatment could enhance the binding capacity of myosin to heptanal/hexanal, especially the binding of myosin to hexanal. The entropy and enthalpy values of their interaction were negative, indicating that the interaction was mainly driven by hydrogen bond and van der Waals force. After ultrasonic treatment, the fluorescence wavelength of myosin-heptanal/hexanal complex was redshifted, the α-helix content was increased, while its roughness values, particle size and the polydispersity index were decreased. These demonstrated that ultrasonic treatment was conducive to myosin binding to heptanal/hexanal, thereby restraining the release of volatile flavor compounds from myosin, which could provide new insights for the regulation of volatile flavor compounds.

Cancer-educated neutrophils promote lung cancer progression via PARP-1-ALOX5-mediated MMP-9 expression.

OBJECTIVE: Neutrophils are one of the most predominant infiltrating leukocytes in lung cancer tissues and are associated with lung cancer progression. How neutrophils promote lung cancer progression, however, has not been established. METHODS: Kaplan-Meier plotter online analysis and tissue immunohistochemistry were used to determine the relationship between neutrophils and overall survival in lung cancer patients. The effect of neutrophils on lung cancer was determined using the Transwell migration assay, a proliferation assay, and a murine tumor model. Gene knockdown was used to determine poly ADP-ribose polymerase (PARP)-1 function in lung cancer-educated neutrophils. Western blot analysis and gelatin zymography were used to demonstrate the correlation between PARP-1 and matrix metallopeptidase 9 (MMP-9). Immunoprecipitation coupled to mass spectrometry (IP/MS) was used to identify the proteins interacting with PARP-1. Co-immunoprecipitation (Co-IP) was used to confirm that PARP-1 interacts with arachidonate 5-lipooxygenase (ALOX5). Neutrophil PARP-1 blockage by AG14361 rescued neutrophil-promoted lung cancer progression. RESULTS: An increased number of infiltrating neutrophils was negatively associated with overall survival in lung cancer patients (P < 0.001). Neutrophil activation promoted lung cancer cell invasion, migration, and proliferation in vitro, and murine lung cancer growth in vivo. Mechanistically, PARP-1 was shown to be involved in lung cancer cell-induced neutrophil activation to increase MMP-9 expression through interacting and stabilizing ALOX5 by post-translational protein modification (PARylation). Blocking PARP-1 by gene knockdown or AG14361 significantly decreased ALOX5 expression and MMP-9 production, and eliminated neutrophil-mediated lung cancer cell invasion and in vivo tumor growth. CONCLUSIONS: We identified a novel mechanism by which PARP-1 mediates lung cancer cell-induced neutrophil activation and PARylates ALOX5 to regulate MMP-9 expression, which exacerbates lung cancer progression.

Effects of polyphenols on the gel and digestive properties of Penaeus vannamei myosin after freezing.

Polyphenols could inhibit the freezing-induced denaturation of myosin, and affect its nutritional and functional properties, which have rarely been studied to date. Therefore, the effects of interactions between polyphenols and myosin after freezing on myosin gel and digestive properties were investigated using low field NMR, a texture analyzer, a dynamic rheometer, ultraviolet-visible spectra, scanning electron microscopy, LC-MS/MS, an automatic amino acid analyzer, etc. Hesperetin (HE), dihydroquercetin (DI), salidroside (SA), and mangiferin (MA) increased the water-holding capacity, non-flowable water content, gel strength, texture, storage modulus, and fractal dimensions of the myosin gel, while modifying its leading force. The results of scanning electron microscopy revealed that the surfaces of polyphenol groups were relatively smoother than those of the control group. Meanwhile, the four types of polyphenols under study significantly improved the gastric and gastrointestinal digestibility of myosin. Furthermore, they significantly increased the contents of essential, flavor, and total free amino acids, as well as the unique peptide numbers in myosin digestion products. This work provides reliable guidance for polyphenols to improve protein function and nutritional properties.

Meat and bone meal stimulates microbial diversity and suppresses plant pathogens in asparagus straw composting.

Meat and bone meal (MBM), as slaughterhouse waste, is a potential biostimulating agent, but its efficiency and reliability in composting are largely unknown. To access the MBM application to the composting process of asparagus straw rice, we followed the composting process for 60 days in 220-L composters and another 180 days in 20-L buckets in treatments applied with MBM or urea. The microbial succession was investigated by high-throughput sequencing. Compared with urea treatments, MBM addition stabilized pH and extended the thermophilic phase for 7 days. The germination index of MBM treatments was 24.76% higher than that of urea treatments. MBM also promoted higher microbial diversity and shifted community compositions. Organic matter and pH were the most significant factors that influence the bacterial and fungal community structure. At the genus level, MBM enriched relative abundances of organic matter-degrading bacteria (Alterococcus) and lignocellulose-degrading fungi (Trichoderma), as well as lignocellulolytic enzyme activities. Notably, MBM addition decreased sum abundances of plant pathogenic fungi of Phaeoacremonium, Acremonium, and Geosmithia from 17.27 to 0.11%. This study demonstrated the potential of MBM as an effective additive in asparagus straw composting, thus providing insights into the development of new industrial aerobic fermentation.

Study on the interactions between the screened polyphenols and Penaeus vannamei myosin after freezing treatment.

The denaturation of proteins (particularly myosin) due to freezing can lead to the deterioration of Penaeus vannamei. The purpose of this study was to verify the antifreeze protective effects of polyphenols screened by a molecular docking technique, and to explore their interactions with myosin after freezing treatment. It was found that the screened polyphenols could significantly increase the freezing rate and unfreezable water content of shrimp paste. The results of fluorescence spectra indicated that the hesperetin to myosin quenching process included both dynamic and static quenching, and it was primarily bound to myosin through hydrophobic interactions; The quenching of myosin by both dihydroquercetin and mangiferin was static quenching, and they were bound to myosin mainly by hydrogen bonds and van der Waals forces; All three of these polyphenols had only one binding site on myosin. Surface hydrophobicity indicated that all four polyphenols were engaged in non-covalent binding (hydrophobic interactions) with myosin. Infrared spectra demonstrated that the addition of these four polyphenols significantly increased the α-helix content of myosin. They also reduced the myosin particle size, zeta potential, and protein degeneration degree. Scanning electron microscopy revealed that the four polyphenols reduced the degree of aggregation, while more uniformly distributing the myosin particles. These observations provide a basis for the screening of polyphenols and further research into the protective mechanism of polyphenols on frozen myosin.

Reassembling of albumin-bound paclitaxel mitigates myelosuppression and improves its antitumoral efficacy via neutrophil-mediated targeting drug delivery.

Albumin-bound paclitaxel (abPTX) has been widely used in cancer treatment. However, dose-related side effects, such as myelosuppression, restrict its clinical application. Cell-based targeting drug delivery is a promising way to mitigate systematic side-effects and improve antitumoral efficacy. In this study, we demonstrated that reassembled abPTX could be engulfed by neutrophils in vivo and delivered to tumor site, thus improving therapeutic efficacy and mitigating myelosuppression. First, in vitro analysis confirmed that reassembling of abPTX formed uniform and stable serum albumin nanoparticles (NP-abPTX) with size of 107.5 ± 2.29 nm and reserved the ability to kill tumor cells. Second, we found that NP-abPTX could be engulfed by activated neutrophil in vitro and in vivo but do not affect neutrophils' function, such as chemotaxis and activation. In a murine tumor model, we further proved that local radiotherapy (RT) induced inflammation activated peripheral neutrophils to capture venous infused NP-abPTX and carry them into tumor tissue. As compared to abPTX, infusion of NP-abPTX dramatically enhanced inhibition of tumor growth treated by local RT and mitigated hematotoxicity. Therefore, our study demonstrated a novel strategy to mitigate side-effects and to improve tumor killing efficacy of abPTX through neutrophil-mediated targeting drug delivery.

Corrigendum: A Novel Role of Connexin 40-Formed Channels in the Enhanced Efficacy of Photodynamic Therapy.

[This corrects the article DOI: 10.3389/fonc.2019.00595.].

The Anti-fibrosis drug Pirfenidone modifies the immunosuppressive tumor microenvironment and prevents the progression of renal cell carcinoma by inhibiting tumor autocrine TGF-ß.

Transforming growth factor-ß (TGF-ß) plays a critical role in regulating cell growth and differentiation. Epithelial to mesenchymal transition (EMT) induced by TGF-ß promotes cancer cell migration, invasion, and proliferation. Pirfenidone (5-methyl-1-phenyl-2(1 H)-pyridone, PFD), an approved drug for treating pulmonary and renal fibrosis, is a potent TGF-ß inhibitor and found reduced incidence of lung cancer and alleviated renal function decline. However, whether PFD plays a role in controlling renal cancer progression is largely unknown. In the present study, we demonstrated that high TGF-ß1 expression was negatively associated with ten-year overall survival of patients with renal cancer. Functionally, blockade of TGF-ß signaling with PFD significantly suppressed the progression of renal cancer in a murine model. Mechanistically, we revealed that PFD significantly decreased the expression and secretion of TGF-ß both in vitro and in vivo tumor mouse model, which further prevented TGF-ß-induced EMT and thus cell proliferation, migration, and invasion. Importantly, the downregulation of TGF-ß upon PFD treatment shaped the immunosuppressive tumor microenvironment by limiting the recruitment of tumor-infiltrating MDSCs. Therefore, our study demonstrated that PFD prevents renal cancer progression by inhibiting TGF-ß production of cancer cells and downstream signaling pathway, which might be presented as a therapeutic adjuvant for renal cancer.

Effects of metal ions on activity and structure of phenoloxidase in Penaeus vannamei.

Phenoloxidase (PO) is a typical metal enzyme, which requires metal ions as prosthetic groups to enable the full exertion of its activity. To study how metal ions affected the activity and structure of PO enzymes, while providing reference materials for in-depth investigations, we examined the effects of different metal ions (Cu2+, Zn2+, Mg2+, Ca2+, and Ba2+) on their activities. Furthermore, Cu2+ and Mg2+ were selected for further investigation through UV spectra, intrinsic fluorescence spectroscopy, AFM, and FTIR. It was revealed that Cu2+ had a more obvious effect on PO compared to Mg2+. The PO could be activated when the concentrations of Cu2+ and Mg2+ were lower than 10-3 and 10-2 mol/L, respectively, and maximum PO activities (182.14% and 141.02%) were observed at 10-4 mol/L concentrations of Cu2+ and Mg2+. When the concentrations of Cu2+ and Mg2+ were higher than 10-2 and 10-1 mol/L, the activities PO were inhibited. The results of the UV-vis and fluorescence spectra revealed that Cu2+ shaped the tertiary structure of PO, whereas the effect of Mg2+ was slight. The AFM results demonstrated that high concentrations of Cu2+ and Mg2+ resulted in PO aggregation. FTIR analysis indicated that the total content of PO α-helices and ß-sheets decreased with higher concentrations of Cu2+ and Mg2+.

Inhibition of Cdk8/Cdk19 Activity Promotes Treg Cell Differentiation and Suppresses Autoimmune Diseases.

Foxp3 expressing regulatory T (Treg) cells, as the central negative regulator of adaptive immune system, are essential to suppress immune response and maintain immune homeostasis. However, the function of Treg cells is frequently compromised in autoimmunity and hyper-activated in infections and tumor microenvironments. Thus, manipulating Treg cells becomes a promising therapeutic strategy for treating various diseases. Here we reported that inhibition of Cdk8/Cdk19 activity by small molecule inhibitors CCT251921 or Senexin A greatly promoted the differentiation of Treg cells and the expression of Treg signature genes, such as Foxp3, CTLA4, PD-1, and GITR. Mechanistically, we found that the augmented Treg cell differentiation was due to sensitized TGF-ß signaling by Cdk8/Cdk19 inhibition, which was associated with attenuation of IFN-γ-Stat1 signaling and enhancement of phosphorylated Smad2/3. Importantly, treatment with Cdk8/Cdk19 inhibitor CCT251921 significantly increased Treg population and ameliorated autoimmune symptoms in an experimental autoimmune encephalomyelitis (EAE) model. Taken together, our study reveals a novel role of Cdk8/Cdk19 in Treg cell differentiation and provides a potential target for Treg cell based therapeutics.

A Novel Role of Connexin 40-Formed Channels in the Enhanced Efficacy of Photodynamic Therapy.

Despite responses to initial treatment of photodynamic therapy (PDT) being promising, a recurrence rate exists. Thus, finding novel therapeutic targets to enhance PDT efficacy is an urgent need. Reports indicate that connexin (Cx) 40 plays an important role in tumor angiogenesis and growth. However, it is unknown whether Cx40-composed channels have effects on PDT efficacy. The study uniquely demonstrated that Cx40-formed channels could enhance the phototoxicity of PDT to malignant cells in vitro and in vivo. Specifically, Cx40-formed channels at high cell density could increase PDT photocytotoxicity. This action was substantially restricted when Cx40 expression was not induced or Cx40 channels were restrained. Additionally, the presence of Cx40-composed channels enhanced the phototoxicity of PDT in the tumor xenografts. The above results indicate that enhancing the function of Cx40-formed channels increases PDT efficacy. The enhancement of PDT efficacy mediated by Cx40 channels was related with intracellular pathways mediated by ROS and calcium pathways, but not the lipid peroxide-mediated pathway. This work demonstrates the capacity of Cx40-mediated channels to increase PDT efficacy and suggests that therapeutic strategies designed to maintain or enhance Cx40 expression and/or channels composed by Cx40 may increase the therapeutic efficacy of PDT.

A novel role of Cx43-composed GJIC in PDT phototoxicity: an implication of Cx43 for the enhancement of PDT efficacy.

In spite of initially promising responses, 5-year recurrence after photodynamic therapy (PDT) sustains high level and an increase in PDT effectiveness is needed. It has been demonstrated that gap junctional intercellular communication (GJIC) formed by Connexin (Cx)43 could improve the transfer of "death signal" between cells, thereby causing the enhancement of cytotoxicity of chemotherapeutics and suicide gene therapy. Nevertheless, whether Cx43-composed GJIC has an effect on PDT phototoxicity remains unknown. This study showed that Cx43-formed GJIC could improve PDT phototoxicity to tumor cells in vitro and in vivo. Specifically, Cx43-formed GJIC under the condition of high cellular density could improve PDT phototoxicity in Cx43-transfected HeLa cells and Cx43-expressing U87 glioma cells. This effect was remarkably inhibited when Cx43 was not expressed or Cx43-formed GJ channels were prohibited. Additionally, the presence of Cx43-mediated GJIC could decrease the mean RTV and tumor weights of xenografts after Photofrin-PDT. The improved PDT efficacy by Cx43-composed GJIC was correlated with stress signaling pathways mediated by ROS, calcium and lipid peroxide. The present study demonstrates the presence of Cx43-composed GJIC improves PDT phototoxicity and suggests that therapeutic strategies designed to upregulate the expression of Cx43 or enhance Cx43-mediated GJIC function may increase the sensitivity of malignant cell to PDT, leading to the increment of PDT efficacy. Oppositely, factors that retard Cx43 expression or prohibit the function of Cx43-mediated GJIC may cause insensitivity of malignant cells to PDT, leading to PDT resistance.

Effect of low frequency ultrasound thawing method on the quality characteristics of Peru squid ( Dosidicus gigas).

The effects of different thawing methods (air thawing, water soak thawing, refrigeration thawing, low frequency ultrasound thawing at 160, 240, 320 and 400 W) on thawing time, thawing loss, cooking loss, water-holding capacity and texture of frozen squid were investigated. The results showed that thawing loss and thawing time were reduced significantly ( p < 0.05) by ultrasound thawing compared with the water soak thawing and air thawing, but the cooking loss had no significant difference ( p > 0.05). Results of the ultrasound thawing especially at 160 and 240 W on microstructure showed less destructive effect on muscle. The microstructure of the muscle was destroyed significantly after air thawing and water soak thawing compared with the ultrasound thawing, which showed that more fibre structure was broken and the gap between the muscle fibres was increased significantly. Low-field NMR results showed that the ability of immobile water shifting to free water after ultrasound thawing was lower than air thawing and water soak thawing, which was consistent with the results of thawing loss and cooking loss. Ultrasound thawing might be chosen as an alternative method to enhance the quality during thawing process.

The neuroprotective and antioxidant activities of protein hydrolysates from grass carp (Ctenopharyngodon idella) skin.

To observe the neuroprotective and antioxidant activities of the grass carp protein hydrolysates (GPH) obtained from grass carp (Ctenopharyngodon idella) skin by enzymatic hydrolysis. GPH prepared using Protamex, at different (5, 10, 15, 20 and 30 %) degrees of hydrolysis (DH) were investigated. The DPPH radial scavenging, reducing power and inhibition of linoleic acid oxidation activities of GPH were significantly improved by a low DH (5 %) compared with those of GPH with a higher DH (p < 0.05). A low degree of enzymatic hydrolysis was appropriate to obtain GPH with improved neuroprotective activities. These results suggest that the control of the DH may be an effective strategy to modify specific neuroprotective and antioxidant activities of GPH, and GPH has potential as a functional food ingredient for related functional and health benefits.

Oridonin inhibits mTOR signaling and the growth of lung cancer tumors.

Oridonin, an active diterpenoid isolated from Rabdosia rubescens, has been widely used for treatment of various types of cancer. It has been shown that oridonin produced an antiproliferative effect in a lung cancer cell line in vitro. However, the antitumor effects of oridonin in lung cancer cells xenograft mice were poorly understood. The aim of the current study was to investigate the antitumor activity of oridonin in vivo and the molecular mechanisms mediating this antitumor efficacy. The human A549 and NCI-H292 non-small cell lung cancer cell lines were transferred to nude mice for the establishment of xenograft models. The results showed that oridonin (10, 20, 40 mg/kg, intraperitoneally) treatment for 28 days significantly decreased tumor volume and induced tumor growth inhibition in both A549 and NCI-H292 xenograft mice. Furthermore, oridonin promoted apoptosis by increasing terminal dUTP nick end labeling-positive cells as well as the ratio of Bax/Bcl-2 in xenograft mice. In addition, chronic oridonin administration inhibited mammalian target of rapamycin (mTORC1) activity by reduction of p-mTOR and p-p70s6k levels, suggesting that the increased apoptosis triggered by oridonin administration was associated with the downregulation of mTORC1 activity. Moreover, inhibition of mTORC1 by rapamycin (2 mg/kg, intraperitoneally) enhanced the anticancer activity of oridonin in mice xenograft models. These findings indicate that treatment with oridonin exhibited antitumor actions through induction of apoptotic response by inhibition of mTORC1 function. Our results also proposed the potential that inhibition of mTORC1 might be an effective target for increasing the therapeutic outcome in lung cancer patients treated with oridonin.