Two newly introduced Wolbachia endosymbionts induce cell host differences in competitiveness and metabolic responses

Wolbachia endosymbionts can induce multiple reproductive manipulations in their hosts, with cytoplasmic incompatibility (CI) being one of the most common manipulations. The important agricultural pests, white-backed planthopper ( Sogatella furcifera ) and brown planthopper ( Nilaparvata lugens ), are usually infected with CI-inducing Wolbachia w Fur and non-CI-inducing Wolbachia w Lug, respectively. The biological effects of these infections when present in a host cell are unknown. Here, we introduced the two Wolbachia strains into an Aedes albopictus cell line to stably establish a w Fur-infected cell line (WFI) and a w Lug-infected cell line (WLI). In a mixed culture, WFI cells were completely replaced by WLI cells, pointing to a stronger competitiveness of the WLI cell line. We found that infection by both Wolbachia strains reduced cell growth rates, but WLI had a faster cell growth rate than WFI, and this difference in cell growth rate combined with possible Wolbachia differences in diffusivity may have affected cell competitiveness. By examining gene expression and metabolites in the two lines, we found that some genes and key metabolites responded to differences in cell competitiveness. These results point to potential mechanisms that could contribute to the relative performance of hosts infected by these strains and also highlight the substantial impact of a non-CI Wolbachia on metabolism, which may in turn influence fitness of its native host. IMPORTANCE Wolbachia transinfection in insects can be used to suppress pests and block virus transmission. We stably introduced two Wolbachia strains from rice planthoppers into cell lines of an important arbovirus mosquito vector, Aedes albopictus . The competitiveness of host cells from the lines infected by the two Wolbachia strains was different, as were metabolic responses of the cell lines. These results suggest potential metabolic effects of Wolbachia on native hosts which could be exploited when they are transinfected into novel hosts for pest control.

The Correlation Between Cell and Nucleus Size is Explained by an Eukaryotic Cell Growth Model

In eukaryotes, the cell volume is observed to be strongly correlated with the nuclear volume. The slope of this correlation depends on the cell type, growth condition, and the physical environment of the cell. We develop a computational model of cell growth and proteome increase, incorporating the kinetics of amino acid import, protein/ribosome synthesis and degradation, and active transport of proteins between the cytoplasm and the nucleoplasm. We also include a simple model of ribosome biogenesis and assembly. Results show that the cell volume is tightly correlated with the nuclear volume, and the cytoplasm-nucleoplasm transport rates strongly influences the cell growth rate as well as the cytoplasm/nucleoplasm ratio. Ribosome assembly and the ratio of ribosomal proteins to mature ribosomes also influence the cell volume and the cell growth rate. We find that in order to regulate the cell growth rate and the cytoplasm/nucleoplasm ratio, the cell must optimally control groups of kinetic parameters together, which could explain the quantitative roles of canonical growth pathways. Finally, using an extension of our model and single cell RNAseq data, it is possible to construct a detailed proteome distribution, provided that a cell division mechanism is known.

We need to bring R0 < 1 to treat cancer too

If each cancer cell produces on average more than one cancer cell, we see a net growth of the tumors and metastases and vice versa. We review recent clinical results for microsatellite stable metastatic colorectal cancer (MSS-mCRC) suggesting immunotherapy combinations with personalized vaccines, checkpoint inhibitors, targeted therapies, multikinase inhibitors, chemotherapies, and radiation that simultaneously slow cancer cell growth rate and enhance T cell killing rate of cancer cells may in future synergize to control the disease.

82 Methyl Donor Supplementation Alters Cytosine Methylation and Biological Processes of Cells Cultured in Divergent Glucose Media Reflecting Improvements in Mitochondrial Respiration and Cell Growth Rate

We hypothesized that supplementation of one-carbon metabolites (OCM: methionine, folate, choline, and vitamin B12) to bovine embryonic tracheal fibroblasts in divergent glucose media would alter cytosine methylation, and alterations in cytosine methylation will reflect biological processes matching previously improved mitochondrial respiration, cell proliferation, and cell growth rate data. Cells were cultured with 1g/L glucose (Low) or 4.5g/L glucose (High). Control medium (CON) contained basal concentrations of folate (0.001g/L), choline (0.001g/L), vitamin B12 (4µg/L), and methionine (0.015g/L). The OCM were supplemented at 2.5 and 5 times (2.5X and 5X, respectively) the CON media, except methionine was limited to 2X across all supplemented treatments. Cells were passaged three times in their treatment media before DNA extraction. Reduced representation bisulfite sequencing was adopted to analyze and compare the genomic methylation patterns within and across treatments using edgeR. Biological processes (BP) were retrieved based on the nearest genes of differentially methylated cytosines (P &lt; 0.01) for each comparison between treatments. In both Low and High treatments, greater OCM increased the proportion of hypomethylated vs. hypermethylated cytosines. Functional analyses pointed out positive regulation of BP related to energy metabolism, except for the contrasts within the High group. Among the BP, we can highlight positive regulation of: GTPase activity, catalytic activity, molecular function, protein modification processes, phosphorylation, protein phosphorylation, cellular protein metabolic processes, MAPK cascade, and metabolic processes. These data support previously reported results from this experiment that showed increased mitochondrial respiration, cell proliferation, and growth rates with increasing OCM levels. We interpret these data to imply that when energy and OCM requirements are met for growth and basal methylation levels, DNA methylation levels decrease which may allow for greater transcription. Thus, OCM can be utilized for other functions such as polyamine synthesis, nucleotide synthesis, energetic metabolites, and phosphatidylcholine synthesis. USDA is an equal opportunity provider and employer.

Quantifying absolute gene expression profiles reveals distinct regulation of central carbon metabolism genes in yeast

In addition to controlled expression of genes by specific regulatory circuits, the abundance of proteins and transcripts can also be influenced by physiological states of the cell such as growth rate and metabolism. Here we examine the control of gene expression by growth rate and metabolism, by analyzing a multi-omics dataset consisting of absolute-quantitative abundances of the transcriptome, proteome, and amino acids in 22 steady-state yeast cultures. We find that transcription and translation are coordinately controlled by the cell growth rate via RNA polymerase II and ribosome abundance, but they are independently controlled by nitrogen metabolism via amino acid and nucleotide availabilities. Genes in central carbon metabolism, however, are distinctly regulated and do not respond to the cell growth rate or nitrogen metabolism as all other genes. Understanding these effects allows the confounding factors of growth rate and metabolism to be accounted for in gene expression profiling studies.

Quantifying absolute gene expression profiles reveals distinct regulation of central carbon metabolism genes in yeast

In addition to specific regulatory circuits, gene expression is also regulated by global physiological cues such as the cell growth rate and metabolic parameters. Here we examine these global control mechanisms by analyzing an orthogonal multi-omics dataset consisting of absolute-quantitative abundances of the transcriptome, proteome, and intracellular amino acids in 22 steady-state yeast cultures. Our model indicates that transcript and protein abundance are coordinately controlled by the cell growth rate via RNA polymerase II and ribosome abundance, but are independently controlled by metabolic parameters relating to amino acid and nucleotide availability. Genes in central carbon metabolism, however, are regulated independently of these global physiological cues. Our findings can be used to augment gene expression profiling analyses in the distantly related yeast Schizosaccharomyces pombe and a human cancer cell model. Our results provide a framework to analyze gene expression profiles to gain novel biological insights, a key goal of systems biology.

A long intergenic non-coding RNA regulates nuclear localisation of DNA methyl transferase-1

ABSTRACTDNA methyl-transferase-1 or DNMT1 maintains DNA methylation in the genome and is important for regulating gene expression in cells. Aberrant changes in DNMT1 activity are observed in many diseases. Therefore, understanding the mechanisms behind alteration of DNMT1 activity is important. Here, we show that CCDC26, a nuclear long non-coding RNA frequently mutated in myeloid leukaemia, directly interacts with DNMT1. In the absence of CCDC26 RNA, DNMT1 is mis-located in the cytoplasm. As a result, genomic DNA is significantly hypomethylated, which is accompanied by a slower cell growth rate and increased cell death. These results point to a previously unrecognised mechanism of long non-coding RNA mediated subcellular localisation of DNMT1 and regulation of DNA methylation. These observations are significant given the importance of DNMT1 in cancer and number of other diseases.

CULTURAL AND BIOCHEMICAL PARAMETERS OF TWO MICROALGAE, PHAEODACTYLUM TRICORNUTUM AND TETRASELMIS SUECIACA, IN CUMULATIVE CULTURES

A comparative study of cultural and biochemical parameters of two microalgal species, Tetraselmis sueciaca and Phaeodactylum tricornutum, was performed. Cell density in the storage culture was 2.88 million cells per one ml for T. sueciaca and 20.37 million cells per one ml for Ph. tricornutum. As shown, determination of op-tical density of the culture medium is a more objective characteristic of the cumulative culture growth. For T. sueciaca, cell growth rate during the course of experiment made 400% and for Ph. tricornutum – 700%. Dif-ference in the chemical composition of microalgal biomass was revealed. The microalgae did not differ in their energy value. The prospects of cumulative culture of microalgae in mariculture farms are discussed.

NT3P75-2 gene-modified bone mesenchymal stem cells improve neurological function recovery in mouse TBI model

Background The attainment of extensive neurological function recovery remains the key challenge for the treatment of traumatic brain injury (TBI). Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) has been shown to improve neurological function recovery after TBI. However, the survival of BMSCs after transplantation in early-stage TBI is limited, and much is unknown about the mechanisms mediating this neurological function recovery. Secretion of neurotrophic factors, including neurotrophin 3 (NT3), is one of the critical factors mediating BMSC neurological function recovery. Gene mutation of NT3 (NT3P75-2) has been shown to enhance the biological function of NT3 via the reduction of the activation of the P75 signal pathway. Thus, we investigated whether NT3P75-2 gene-modified BMSCs could enhance the survival of BMSCs and further improve neurological function recovery after TBI. Methods The ability of NT3P75-2 induction to improve cell growth rate of NSC-34 and PC12 cells in vitro was first determined. BMSCs were then infected with three different lentiviruses (green fluorescent protein (GFP), GFP-NT3, or GFP-NT3P75-2), which stably express GFP, GFP-NT3, or GFP-NT3P75-2. At 24 h post-TBI induction in mice, GFP-labeled BMSCs were locally transplanted into the lesion site. Immunofluorescence and histopathology were performed at 1, 3, and/or 7 days after transplantation to evaluate the survival of BMSCs as well as the lesion volume. A modified neurological severity scoring system and the rotarod test were chosen to evaluate the functional recovery of the mice. Cell growth rate, glial activation, and signaling pathway analyses were performed to determine the potential mechanisms of NT3P75-2 in functional recovery after TBI. Results Overall, NT3P75-2 improved cell growth rate of NSC-34 and PC12 cells in vitro. In addition, NT3P75-2 significantly improved the survival of transplanted BMSCs and neurological function recovery after TBI. Overexpression of NT3P75-2 led to a significant reduction in the activation of glial cells, brain water content, and brain lesion volume after TBI. This was associated with a reduced activation of the p75 neurotrophin receptor (P75NTR) and the c-Jun N-terminal kinase (JNK) signal pathway due to the low affinity of NT3P75-2 for the receptor. Conclusions Taken together, our results demonstrate that administration of NT3P75-2 gene-modified BMSCs dramatically improves neurological function recovery after TBI by increasing the survival of BMSCs and ameliorating the inflammatory environment, providing a new promising treatment strategy for TBI.