Project description:Human serum amyloid A (SAA) is a major acute phase protein and shows a massive increase of concentration in plasma during inflammation. In the current study, we report that recombinant human and mouse SAA1 (rhSAA1 and rmSAA1) have a potent antifungal activity against the major fungal pathogen Candida albicans. rhSAA1 binds to the cell surface of C. albicans and promotes cell aggregation. At high concentrations, rhSAA1 disrupts the membrane integrity and induces rapid cell death of C. albicans. Further investigation demonstrates that rhSAA1 targets on the cell wall adhesin Als3 of C. albicans. Inactivation of ALS3 in C. albicans leads to remarkably decreased cell aggregation and death upon rhSAA1 treatment, implying that Als3 plays a critical role in SAA1 sensing. Moreover, deletion of the ALS3 transcriptional regulators such as AHR1, BCR1, and EFG1 in C. albicans results in a similar effect on cell responses to that of the als3/als3 mutant upon rhSAA1 treatment. Global gene expression profiling analysis indicates that rhSAA1 has a remarkable impact on the expression of cell wall- and metabolism-related genes in C. albicans. Our finding of the antifungal activity of rhSAA1 against C. albicans expands the function of this protein and would provide new insights into the understanding of the host-Candida interaction during infections.
Project description:Metastasis is the key determinant of poor prognosis for advanced-stage NSCLC patients. Although an important contributor to metastasis is cross-talk between tumor-associated macrophages (TAMs) and tumor cells, its regulation is not fully understood. Expressed primarily in macrophages, scavenger receptor A1 (SR-A1) has been associated with lung tumorigenesis. Here, the mechanistic basis for the involvement of SR-A1 in lung cancer prognosis was investigated using population genetics, transcriptomics, and functional analyses. SR-A1 genetic variants were investigated for possible association with survival of advanced-stage NSCLC patients in the Harvard Lung Cancer Study cohort. Two SNPs (rs17484273, rs1484751) in SR-A1 were significantly associated with poor overall survival of NSCLC patients. Further, data from The Cancer Genome Atlas showed a considerable down-regulation of SR-A1 in lung tumor tissues. The association of SR-A1 with prognosis was validated in animal models in the context of lung cancer metastasis. Macrophages derived from SR-A1 knockout mice accelerated metastasis in a lung cancer mouse model. On the other hand, tumor cell seeding, migration, and invasion as well as macrophage accumulation in lung cancer tissue were enhanced in SR-A1 knockout mice. Furthermore, SR-A1 deficiency promoted up-regulation of serum amyloid A1 (SAA1) in macrophages, which appeared to be mediated by MAPK/Ikappa-B/NF-kappaB signaling. Further, SAA1 exposure promoted tumor cell invasion and macrophage migration in vitro and in vivo, but these effects were blocked by administration of an anti-SAA1 antibody. These findings suggest that SR-A1 may suppress lung cancer metastasis by down-regulating SAA1 production in macrophages.
Project description:Macrophages are important regulators of the immune system and are critically involved in the pathophysiology of many diseases. Serum amlyoidosis is a protein misfolding disease which can follow chronic inflammatory conditions. Deposition of fibrils formed from serum amyloid A1 (SAA1) protein occurs systemically and can lead to severe or even fatal outcomes. Macrophages play a critical role in the misfolding and deposition of SAA1-derived fibrils and the role of macrophages in this context has been studied extensively. It is known that SAA1 can bind to some surface receptors on macrophages and it is taken up by the macrophages and metabolized in the lysosomes. On the other hand, the effect of SAA1 on macrophage physiology has been much less investigated so far. Therefore, we aim to investigate the effect of SAA1 on macrophage gene expression by gene microarray analysis. To this end, primary peritoneal macrophages from NMRI mice were treated with endotoxin-free recombinantly expressed full-length mSAA1 for 6 and 24 h and gene expression was analyzed.
Project description:Mammalian serum amyloid A (SAA) is a major acute phase protein that shows a massive increase in plasma concentration during inflammation. In the present study, we demonstrate that the expression of mouse SAA1 in serum was increased when infected with Candida albicans, a major human fungal pathogen, in a systemic infection model. We then set out to investigate the antifungal activity of SAA proteins against C. albicans Recombinant human and mouse SAA1 (rhSAA1 and rmSAA1) were expressed and purified in Escherichia coli Both rhSAA1 and rmSAA1 exhibited a potent antifungal activity against C. albicans We further demonstrate that rhSAA1 binds to the cell surface of C. albicans, disrupts cell membrane integrity, and induces rapid fungal cell death in C. albicans Our finding expands the known functions of SAA1 and provides new insight into host-Candida interactions during fungal infection.
Project description:This study attemps to study the global effects of Serum Amyloid A (SAA) on human endothelial gene expression profile in different time points. Keywords: time course
Project description:Candida albicans were treated with a sublethal concentration of the antifungal Jagaricin for either a short time (30 min) or until an OD of 0.5 (indicating log growth) was reached. Controls were grown without any antifungal to determine cellular reactions to the compound.
Project description:Sampangine, a plant-derived alkaloid found in the Annonaceae family, exhibits strong inhibitory activity against the opportunistic fungal pathogens Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. In the present study, transcriptional profiling experiments coupled with the analysis of mutants were performed in an effort to elucidate its mechanism of action. Using Saccharomyces cerevisiae as a model organism, we show that sampangine produces a transcriptional response indicative of hypoxia, altering the expression of genes known to respond to low oxygen conditions. Several additional lines of evidence obtained suggest that these responses could involve effects on heme. First, the hem1 deletion mutant lacking the first enzyme in the heme biosynthetic pathway showed increased sensitivity to sampangine, and exogenously supplied hemin partially rescued the inhibitory activity of sampangine in wild-type cells. In addition, heterozygous mutants with deletions in genes involved in five out of eight steps in the heme biosynthetic pathway showed increased susceptibility to sampangine. Furthermore, spectral analysis of pyridine extracts indicated significant accumulation of free porphyrins in sampangine-treated cells. Transcriptional profiling experiments were also performed in C. albicans to investigate the response of a pathogenic fungal species to sampangine. Taking into account the known differences in the physiological responses of C. albicans and S. cerevisiae to low oxygen, significant correlations were observed between the two transcription profiles suggestive of heme-related defects. Our results indicate that the antifungal activity of the plant alkaloid sampangine is due, at least in part, to perturbations in the biosynthesis or metabolism of heme. GSE10073: Gene expression response to the antifungal compound sampangine in S. cerevisiae GSE10075: Gene expression response to the antifungal compound sampangine in C. albicans Keywords: SuperSeries Refer to individual Series
Project description:The glucocorticoid-inducible protein annexin A1 has been shown to function as key-regulator of the resolution phase of inflammation but its role in immune-mediated crescentic glomerulonephritis has not been studied so far. Acute crescentic glomerulonephritis was induced in annexin A1 deficient and wildtype mice using a sheep serum against rat glomerular basement membrane constituents. Alterations in gene expression were determined by RNA-Seq and gene ontology analysis. Intrinsic annexin A1 has a protective effect in reducing pro-inflammatory signals and infiltration of neutrophil granulocytes during crescentic GN. The annexin A1 signaling cascade may therefore provide novel targets for the treatment of inflammatory kidney disease.
Project description:Effect of HDL enriched with Serum Amyloid A1 (HDL+SAA1) on Gene Expression by Classical CD14+/CD16- Human Peripheral Blood Monocytes from Asthmatics