Project description:In this study we are examining the paracrine effect induced by feline calicivirus (FCV) infection on stress granule (SG) accumulation. We provided an understanding of paracrine granules function and specificity through their affinity purification followed RNAseq to systematically analyse their RNA content.
Project description:We are here presenting a new paracrine induction of RNA granules by viruses. Infection by viruses imposes major stress on the host cell. In response to this stress, infected cells can induce several defence mechanisms, which include the activation of stress response pathways and the innate immune response. These often result in an inhibition of translation culminating in the assembly of cytoplasmic granules called stress granules (SGs). SGs assembly follows from liquid phase separation of aggregation-prone proteins such G3BP1 and TIA-1, leading to the sequestration of mRNAs. Because this threatens viral gene expression, viruses need to evade these stress response pathways to propagate. Using feline calicivirus (FCV), surrogate for norovirus, the main virus responsible for gastroenteritis outbreaks worldwide, we previously showed that FCV impairs SGs assembly by cleaving the scaffold protein G3BP1. Interestingly, we observed that uninfected bystander cells assembled G3BP1 granules, suggesting a paracrine response trigged by the infection. We now present evidence that virus-free supernatant generated from infected cells can induce the formation of RNA granules. We have characterised the dynamic of the granules assembly via confocal microscopy. Moreover, we provide an understanding of paracrine granules function and specificity through their affinity purification followed by proteomics and RNAseq analysis of their proteins and mRNAs content. This helps to define rules of assembly and novel functions for paracrine granules highlighting fundamental differences with canonical stress granules.
Project description:Purpose:MicroRNAs (miRNAs) are members of a rapidly growing class of small endogenous non-coding RNAs that play crucial roles in post-transcriptional regulator of gene expression in many biological processes. Feline Panleukopenia Virus (FPV) is a highly infectious pathogen that causes severe disease in pets, economically important animals and wildlife in worldwide. However, the molecular mechanisms underlying the pathogenicity of FPV have not been completely clear. To study the involvement of miRNAs in the FPV infection process, miRNAs expression profiles were identified via deep sequencing in the feline kidney cell line (F81) infected and uninfected with FPV. Methods:miRNA-sequencing analysis was performed on an Illumina Hiseq 2500 (LC Sciences, USA) following the vendor's recommended protocol Results:As a result, 673 known miRNAs belonging to 210 families and 278 novel miRNAs were identified. Then we found 57 significantly differential expression miRNAs by comparing the results between uninfected and FPV-infected groups. Furthermore, stem-loop qRT-PCR was applied to validate and profile the expression of the randomly selected miRNAs; the results were consistent with those by deep sequencing. Furthermore, the potential target genes were predicted. The target genes of differential expression miRNAs were analyzed by GO and KEGG pathway. Conclusions:The identification of miRNAs in feline kidney cell line before and after infection with Feline Panleukopenia Virus will provide new information and enhance our understanding of the functions of miRNAs in regulating biological processes.
Project description:Senescence, the irreversible cell cycle arrest of damaged cells, is accompanied by a deleterious pro-inflammatory senescence-associated secretory phenotype (SASP). Senescence and the SASP are major factors in aging, cancer, and degenerative diseases, and interfere with the expansion of adult cells in vitro, yet little is known about how to counteract their induction and deleterious effects. Paracrine signals are increasingly recognized as important senescence triggers and understanding their regulation and mode of action may provide novel opportunities to reduce senescence-induced inflammation and improve cell-based therapies. Here, we show that the signalling protein WNT3A counteracts senescence in cultured human adult multipotent stromal cells (MSCs) by limiting paracrine senescence. We find that entry into senescence in a small subpopulation of MSCs triggers a secretome that causes a feed-forward signalling cascade that with increasing speed induces healthy cells into senescence. WNT signals interrupt this cascade by repressing cytokines that mediate this induction of senescence. Inhibition of those mediators by interference with NF-kB or interleukin 6 signalling reduced paracrine senescence in absence of WNT3A and promoted the expansion of MSCs. Our work reveals how WNT signals can antagonize senescence and has relevance not only for expansion of adult cells but can also provide new insights into senescence-associated inflammatory and degenerative diseases. // The RNAseq data in particular focusses on the transcriptome changes in MSCs occuring in vitro culture over four passages in presence or absence of growth factors WNT3A and FGF2.
Project description:The purpose of this study was to characterize the transcriptomic alterations accompanying the inflammation involved in feline chronic gingivostomatitis (FCGS). Towards this goal next-generation sequencing (NGS)-based gene expression profiling (RNA-Sequencing; RNA-Seq) was performed on matched pairs of FCGS diseased and healthy tissues obtained from three feline subjects.
Project description:This study looks at the effect of dietary manipulation on the development of hepatic steatosis and changes in hepatic gene expression in a feline model. We used microarray analysis to examine changes in hepatic gene transcription in response to Trans fat, High Fructose Corn Syrup (HFCS) and/or Monosodium Glutamate (MSG) in the domestic cat. The use of human Affymetrix arrays for the study of feline gene expression has previously been validated by Dowling and Bienzle, 2005, Journal of General Virology. 86(Pt 8), 2239-48 (PMID 16033971).
Project description:This study looks at the effect of dietary manipulation on the development of hepatic steatosis and changes in hepatic gene expression in a feline model. We used microarray analysis to examine changes in hepatic gene transcription in response to Trans fat, High Fructose Corn Syrup (HFCS) and/or Monosodium Glutamate (MSG) in the domestic cat. The use of human Affymetrix arrays for the study of feline gene expression has previously been validated by Dowling and Bienzle, 2005, Journal of General Virology. 86(Pt 8), 2239-48 (PMID 16033971). Our study animals were bred from female Felis catus previously placed on one of 4 different dietary regimens for a period of 3 weeks prior to mating. The four dietary regimens used in this study were: [1] Standard Chow Control feline diet (Test Diet Purina catalog #5003); [2] MSG diet consisting of Control diet with 1.125% added Monosodium Glutamate (Diet A: Test Diet Purina catalog #5C1J); [3] Trans-fat/HFCS diet, containing 8.6% Trans fat and 24% HFCS (Diet B: Test Diet Purina catalog #5B4K); and [4] Trans-fat/HFCS and MSG diet, containing 8.6% Trans fat, 24% HFCS and 1.125% MSG (Diet C: Test Diet Purina catalog #5C1H). Following mating, the 4 groups of dams were maintained on their respective diets throughout the gestation and nursing period. Male offspring used in the following experiments were weaned onto the same diets and maintained on their respective dietary regimens until they reached 9 months of age. Hepatic tissues (4-5 per diet group) were used for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Cell division ensures that both genetic information and non-genetic contents are inherited by daughter cells. Whereas considerable detail has been learned about the processing of intact or damaged DNA during the cell cycle (Branzei & Foiani, 2008; Klaasen et al., 2022),(Bakhoum & Cantley, 2018),(Hustedt & Durocher, 2016), how daughter cells deal with other forms of inherited damage is unknown. Here we identified a special kind of cytoplasmic granules responsible for the compartmentalisation of parental RNA damage. We found that ultraviolet (UV)-induced RNA, but not DNA, damage triggered assembly of this unique type of granules characterized by the presence of RNA helicase DHX9. By developing a novel methodology, FANCI, we discovered that DHX9 granules are enriched in damaged intron RNA and pre-mRNA-binding proteins, which is in contrast to other classical stress granules (SGs) that are composed of mature mRNA. Intron damage impeded proper splicing and intron decay, and induced generation of circRNA and dsRNA in the granules. Moreover, we showed that intron damage induced DHX9 granules assembled specifically in postmitotic daughter cells and triggered a cellular dsRNA immune response. Condensation with dsRNA is crucial for DHX9 localization to the granules and the modulation of dsRNA in these granules by DHX9 was crucial for daughter cell survival. Our observations revealed that DHX9 granules constitute a dedicated non-membrane-bound cytoplasmic compartment that protects daughter cells from parental damaged RNA.