Project description:In vertebrates, all cells except circulating blood cells must adhere to support their normal growth and functions. The adherence to extracellular matrix and/or other cells is critical and adherent cells placed in non-adherent conditions either die or form multicellular spheroids. Placing cells in non-adherent conditions has been used to induce differentiation in teratocarcinoma cells and more recently to form organoids . Because of such important consequences induced by cell adhesion on cell growth and function, the transition between adherent and non-adherent states is rather rare. There are however physiological situations, such as blood cells diapedesis, during which cells that circulate into the blood stream must adhere to the endothelial cells and cross the endothelial barrier to reach target tissues. Another example of transition, from an adherent to a non-adherent state, is observed in the metastasic process, where cells detach from the tumor mass and circulate in the blood and lymphatic vasculature prior to reattaching and extravasating to colonize distant organs. The comparative analysis of the only effects of adherence on cellular functions is complicated by the fact that in many study models the acquisition or loss of adherence induces major alterations in cell physiology that would obscure the effects of the adherence itself. For example, P19 teratocarcinoma cells differentiate in suspension spheroids while they do not in adhering conditions. In this context, the comparison between spheroids and adherent cells would not be a comparison between adherent and non-adherent cells, but between differentiated cells adhering between them and undifferentiated cells adhering on plastic. Mouse macrophage cell lines represent one of the rare experimental models that may be suitable to compare the adherent and non-adherent states. Indeed, they grow equally well under adherent and non-adherent conditions and keep their differentiated functions under both conditions. We therefore decided to use this model to analyze the changes between the adherent and the non-adherent state using a broad approach, based on proteomics.
Project description:Brucella, a notorious intracellular pathogen, causes chronic infections in many mammals, including humans. The twin-arginine translocation (Tat) pathway transports folded proteins across the cytoplasmic membrane; protein substrates translocated by Brucella include ABC transporters, oxidoreductases, and cell envelope biosynthesis proteins. Previously, we showed that a Tat mutant of Brucella melitensis M28 exhibits reduced survival within murine macrophages. In this study, we compared the host responses elicited by wild-type M28 and its Tat-mutant strains ex vivo. We utilized label-free quantitative proteomics to assess proteomic changes in RAW264.7 macrophages after infection with M28 and its Tat mutants.
Project description:Using Solexa/Illumina's digital gene expression (DGE) system, a tag-based transcriptome sequencing method, we investigated the kinetic transcriptional profile of gene expression in macrophages infected with Brucella melitensis strain 16M. A key aspect of Brucella virulence is their ability to proliferate within professional and nonprofessional phagocytic host cells, thereby successfully bypassing the bactericidal effects of phagocytes. Their virulence and chronic infections are thought to be due to their ability to avoid the killing mechanisms within host cells. Defining the interaction between a host cell and Brucella is crucial to understanding the infectious process. Most researchers have studied the pathogens, but the host plays a very important role during infections. To date, relatively few host factors have been shown important in Brucella infections. However, little is known about the host networks that mediate infection. The objective of the study is to analyze the genes and cellular components related to the innate immunity response to determine the mechanisms through which Brucella avoids the host innate immunity. A total of 3576 and 3962 genes that are differentially expressed between 0 and 4 h and between 0 and 24 h were identified. The identified genes are related to immune processes, signal transduction, inflammation, apoptosis, cell membrane, transcriptional regulation, and intracellular trafficking. Our data have added to the current understanding of different host gene expressions during different infection phases by Brucella spp. The RAW264.7 cells were seeded into 24-well plates at 5-105 cells/well, incubated in 5% CO2 at 37 M-BM-0C for 24 h, and then infected with Brucella at a multiplicity of infection of 200. To synchronize the infection, the infected plates were centrifuged at 200 ug for 5 min at room temperature and then incubated at 37 M-BM-0C for 20 minutes. The infected cell monolayers were washed three times with PBS, overlaid with 0.5 ml of DMEM containing 100 mg/ml of ampicillin and 50 mg/ml of kanamycin at 37 M-BM-0C for 0, 4, and 24 h. At the end of the incubation period, the culture medium was removed and centrifuged at 1500 rpm for 15 min. The cell pellet and adherent cells were resuspended in TRIzol. Total RNA were extracted from the cells at 0, 4 and 24 h post infection.
Project description:Botulinum neurotoxin type A (BoNT/A) is one of the most potent protein toxins, which makes it a possible biological weapon and therapeutic. Using microarray analysis we performed global transcriptional profiling of RAW264.7 cells, a murine alveolar macrophage cell line. Time dependent expression profiles after treatment of 1nM or 5nM Botulinum neurotoxin A
Project description:Endoplasmic reticulum stress (ERS) regulates the function of immune cells in the tumor microenvironment and suppresses the antitumor immune response. In order to formulate the TME of ERS-GC, we cocultured the human CAFs with the supernatant of human gastric cancer cells stimulated by TM. Mass spectrometry sequencing revealed that ERS state regulated the overexpression of 58 proteins and downregulation of the expression of 56 proteins in CAFs, including m6A-modified proteins and SEMA3A, an immunosuppression-related protein.
Project description:How histone posttranslational modifications (PTMs) are inherited through cell cycle remains poorly understood. Canonical histones are made in the S phase of cell cycle. Combining mass spectrometry-based technologies and stable isotope labeling by amino acids in cell culture (SILAC), we interrogate the distributions of multiple major histone PTMs on old versus new histones in synchronized human cells. We show that histone PTMs can be grouped to three categories accordingly to their distributions. Most lysine mono-methylation and acetylation PTMs are either symmetrically distributed on old and new histones, or asymmetric on new histones. In contrast, most di- and tri-methylation PTMs are asymmetric on old histones, suggesting the inheritance of different PTMs is regulated distinctly. Intriguingly, old and new histones are distinguished in their phosphorylation status during early mitosis, in three different human cell types: Hela, 293T and human foreskin fibroblast (HFF) cells. The mitotic hallmark H3S10ph is predominantly associated with old H3 at early mitosis and become symmetric with the progression of mitosis. The same distribution pattern is found on other mitotic histone phosphorylation marks, including H3T3/T6ph, H3.1/2S28ph and H1.4S26ph, excluding S28/S31ph on the H3 variant H3.3. Although H3S10ph often associates with the neighboring K9 di- or tri-methylation, they are not required for the asymmetric distribution of S10ph on the same H3 tail. Inhibition of the kinase Aurora B does not change the distribution pattern despite significant reduction of H3S10ph levels. K9me2 abundance on the new H3 is significantly reduced after Aurora B inhibition, suggesting a crosstalk between H3S10ph and H3K9me2.
Project description:Errors in protein synthesis are thought to be rare, yet cells representing the diversity of life tolerate greatly elevated levels of error. One source of translation error in humans are anticodon mutations in transfer RNAs (tRNAs). We found a tRNA Ser AGA -2-3 variant (G35A) that occurs in 2% of the human population causes mis-incorporation of serine (Ser) at phenylalanine (Phe) codons. We developed a dual fluorescent reporter to quantify mis-incorporation levels in live cells, including β-lymphocyte lines from the 1000 genomes project with wild-type or mutant A35 alleles. The mutant cells showed reduced viability, and tRNA sequencing confirmed expression, hypo-modification of C32, and 5’- fragment generation of the mutant tRNA Ser AAA . Transfection with our fluorescent reporter and mass spectrometry confirmed Ser mis-incorporation. The data demonstrate that a natural human genome encoded tRNA mutant causes mistranslation. Our findings have important implications for translation fidelity in humans and the application of missense suppressor tRNAs in medicine.
Project description:Drug target identification is a critical step towards the understanding of the mechanism of action of a drug, which will help to improve the current therapeutic regime and to expand the drug’s therapeutic potential. However, current in vitro affinity chromatography-based and in vivo activity- based protein profiling (ABPP) approaches generally face difficulties discriminating specific drug targets from non-specific ones. Here we describe a novel approach combining isobaric tag for relative and absolute quantitation (iTRAQ) with Clickable ABPP, named ICABPP, to specifically and comprehensively identify the protein targets of andrographolide (Andro), a natural product with known anti-inflammation and anti-cancer effects, in live cancer cells. We identified a spectrum of specific targets of Andro, which furthered our understanding of the mechanism of action of the drug. We found that Andro has a potential novel application as the tumor metastasis inhibitor, which was validated through cell migration and invasion assays. Moreover, we have unveiled the target binding mechanism of Andro with a combination of drug analogue synthesis, protein engineering and mass spectrometry-based approaches and determined the drug-binding sites of two protein targets, NF-kappaB and actin.
Project description:Investigating the response of long non-coding RNA expression to LPS stimulation in human monocytes. This experiment is related to the RNA-seq study E-MTAB-2399.
Project description:Macrophages play a critical role in innate immunity, and the expression of early response genes orchestrate much of the initial response of the immune system. Macrophages undergo extensive transcriptional reprogramming in response to inflammatory stimuli such as Lipopolysaccharide (LPS). To identify gene transcription regulation patterns involved in early innate immune responses, we used two genome-wide approaches - gene expression profiling and chromatin immunoprecipitation-sequencing (ChIP-seq) analysis. We examined the effect of 2 hrs LPS stimulation on early gene expression and its relation to chromatin remodeling (H3 acetylation; H3Ac) and promoter binding of Sp1 and RNA polymerase II phosphorylated at serine 5 (S5P RNAPII), which is a marker for transcriptional initiation. Our results indicate novel and alternative gene regulatory mechanisms for certain proinflammatory genes. We identified two groups of up-regulated inflammatory genes with respect to chromatin modification and promoter features. One group, including highly up-regulated genes such as tumor necrosis factor (TNF), was characterized by H3Ac, high CpG content and lack of TATA boxes. The second group, containing inflammatory mediators (interleukins and CCL chemokines), was up-regulated upon LPS stimulation despite lacking H3Ac in their annotated promoters, which were low in CpG content but did contain TATA boxes. Genome-wide analysis showed that few H3Ac peaks were unique to either +/-LPS condition. However, within these, an unpacking/expansion of already existing H3Ac peaks was observed upon LPS stimulation. In contrast, a significant proportion of S5P RNAPII peaks (approx 40%) was unique to either condition. Furthermore, data indicated a large portion of previously unannotated TSSs, particularly in LPS-stimulated macrophages, where only 28% of unique S5P RNAPII peaks overlap annotated promoters. The regulation of the inflammatory response appears to occur in a very specific manner at the chromatin level for specific genes and this study highlights the level of fine-tuning that occurs in the immune response. 2 pairs of THP-1 cells either stimulated with LPS or not. ChIP using either H3K9/K14Ac, RNA Pol II (phospho S5) or SP1 antibody. This submission represents chip-seq component of study.