Project description:Pathogenic Candida fungi are a leading cause of opportunistic, hospital-associated bloodstream infections with high mortality rates, typically in immunocompromised patients. Several species, including C. albicans, the most prevalent cause of infection, belong to the monophyletic CUG clade of yeasts. Much is known about the interaction of C. albicans with innate immune cells, which are crucial for controlling infection. Phagocytosis of C. albicans elicits transcriptional induction of several pathways involved in catabolism of non-glucose carbon sources that are important for virulence, termed alternative carbon metabolism. However, the response of other CUG clade species has not been characterized. In a separate dataset, we profiled transcriptional responses to primary murine bone marrow derived macrophages in six Candida species. Here we additionally profiled the response of M. guilliermondii, a yeast that is known as a cause of disseminated candidiasis as well as cutaneous infections. We find that similar to other CUG-clade Candida species, it mounts a robust alternative carbon metabolism response to phagocytosis.
Project description:Inhalation of the amibient air polution ozone causes lung inflammation and can suppress host defense mechanisms, including impairing macrophage phagocytosis. Ozone reacts with cholesterol in the lung to form oxysterols, like secosterol A and secosterol B, which can form covalent adducts on cellular proteins. How oxysterol-protein adduction modifies the function of lung macrophages is unknown. Herein, we used a preoteomic screen to identify lung macrophage proteins that fomr adducts with ozone-derived oxysterols. Analysis show that the phagocytic receptor CD206 and CD64 formed adducts with secosterol A. Adduction of these receptors with ozone-derived oxysterols impaired ligand binding and corresponded with reduced macrophage phagocytosis. This work suggests a novle mechanism for the suppression of macrophage phagocytosis following ozone exposure through the generation of oxysterols and the formation of oxysterol-protein adducts on phagocytic receptors.
Project description:Natural grape-juice fermentations involve the sequential development of different yeast species which strongly influence the chemical and sensorial traits of the final product. In the present study,we aimed to examine the transcriptomic response of Saccharomyces cerevisiae to the presence of Hanseniaspora guilliermondii wine fermentation. Paralell fermentations were carried out in natural grape-juice using S. cerevisiae for both single and mixed culture with a H. guilliermondii strain. For RNA extraction, cells were collected at 24h, 48h and 96 h from both fermentations
Project description:Meyerozyma guilliermondii, which was isolated from pears by our laboratory, M. guilliermondii had a significant effect on the induction of several defense-related genes compared to the control. It revealed the defense response mechanism of pears by transcriptomics, and investigated the function of more defense-related genes in pears.
Project description:Antagonistic yeasts inhibit the growth of fungal. In our previous research, Meyerozyma guilliermondii one of antagonistic yeasts exhibits antagonistic activity against Penicillium expansum. However, the mechanisms, especially the molecular mechanisms of inhibiting activity of M. guilliermondii are not clear. In this study, the transcriptome characterization of P. expansum induced by M. guilliermondii were investigated.
Project description:Natural grape-juice fermentations involve the sequential development of different yeast species which strongly influence the chemical and sensorial traits of the final product. In the present study,we aimed to examine the transcriptomic response of Saccharomyces cerevisiae to the presence of Hanseniaspora guilliermondii wine fermentation.
Project description:Ras homolog enriched in brain (Rheb1) is a small GTPase and is known to be a direct activator of mTORC1. Dysregulation of Rheb1 has been shown to impair the cellular-energetic state and cell homeostasis. However, the role of Rheb1 in monocytes/macrophages differentiation and maturation is not clear. Here, we investigate the role of Rheb1 in mouse myelopoiesis using a Rheb1 conditional deletion murine model. We found that the absolute number of macrophages decreased in the bone marrow (BM) of Rheb1-deficient mice. Loss of Rheb1 inhibited the monocyte-to-macrophage differentiation process. Additionally, Rheb1 deletion reduced phagocytosis ability of macrophages by inhibiting the mTORC1 signaling pathway. Furthermore, 3BDO (an activator of mTORC1) rescued the phagocytosis ability of Rheb1-deficient macrophages. Thus, Rheb1 is critical for macrophage production and phagocytosis and executes these activities possibly via mTORC1-dependent pathway.
Project description:We studied macrophage gene expression from mice fed chow diet (C) or 60% high fat diet (HF), that phagocytized C-RBC, HFD-RBC, or no RBC. Macrophages from mice on HF diet were activated toward a pro-inflammatory phenotype. In macrophages isolated from CD mice, RBC phagocytosis yielded a gene expression pattern similar to HF macrophages. Incubation of HF-RBC with macrophages resulted in a significantly more pronounced upregulation of pro-inflammatory chemokines as compared to C-RBC. Peritoneal macrophages were obtained from C57BL/6 mice fed either C or HF diet. Phagocytosis was performed in vitro with C-RBC or HF-RBC; macrophages not exposed to RBC served as a control. Affymetrix Mouse Gene 1.0 ST microarray chips were used to assess the gene expression profile.
Project description:Phagocytosis requires the activation of a plethora of mechanisms that include the activation of the actin cytoskeleton guided by the Arp2/3 complex. These are promoted by activators such as the Wiskott Aldrich Syndrome Protein (WASP) family members. In order to further understand the molecular mechanisms involved in the early events leading the phagocytosis of the pathogenic Mycobacterium tuberculosis, we set out to examine potential roles of miRNAs in phagocytosis using genome-wide expression profiling to identify miRNAs differentially regulated following mycobacterial infection. One of the miRNAs activated upon infection of mouse macrophages with the non-pathogenic Mycobacterium smegmatis, the widely conserved miR-142-3p, was predicted and confirmed to target the Neural-WASP (N-WASP). Upregulating of miR-142-3p in mouse macrophages inversely correlated with levels of N-WASP, upon infection with live pathogenic and non-pathogenic mycobacteria, suggesting an active role of Mycobacterium tuberculosis on the regulation of phagocytosis, at the post-transcriptional level, in host cells. The reduction of N-WASP correlated with a reduced internalization of bacteria per macrophage, independently of the phagocytosis index. Furthermore, the downregulation of WASP levels accompanied those of N-WASP, at early but not at late time points, suggesting a closely regulatory mechanism among both family members, dependent on the time frame of the phagocytosis. Additionally, upregulating of miR-142-3p promoted the change in the protein levels of another predicted and confirmed target, the Cofilin2 protein, in a phagocytosis-independent fashion. Downregulation experiments promoted aberrant morphologic phenotypes in macrophages, similar to observed by others in PBMCs of humans with Wiskott Aldrich Syndrome, suggesting the strong involvement of miR-142-3p on the regulation of the actin machinery in macrophages. Altogether these results show for the first time that miRNAs are involved in the regulation of actin-mediated phagocytosis of pathogenic bacteria and that these are direct targets of Mycobacterium tuberculosis. Expression analysis of mouse macrophage cell line J774A.1 in response to infection with Mycobacterium smegmatis mc2155 EGFP. Three biological replicates each for uninfected and infected samples.