ABSTRACT
The fungus Trichophyton schoenleinii (T. schoenleinii) is the causative agent of Trichophytosis and Tinea favosa of the scalp in certain regions of Eurasia and Africa. Human innate immune system plays an important role in combating with various pathogens including fungi. The inflammasome is one of the most critical arms of host innate immunity, which is a protein complex controlling maturation of IL-1β. To clarify whether T. schoenleinii is able to activate the inflammasome, we analyzed human monocytic cell line THP-1 for IL-1β production upon infection with T. schoenleinii strain isolated from Tinea favosa patients, and rapid IL-1β secretion from THP-1 cells was observed. Moreover, applying competitive inhibitors and gene specific silencing with shRNA, we found that T. schoenleinii induced IL-1β secretion, ASC pyroptosome formation as well as caspase-1 activation were all dependent on NLRP3. Cathepsin B activity, ROS production and K⁺ efflux were required for the inflammasome activation by T. schoenleinii. Our data thus reveal that the NLRP3 inflammasome plays an important role in host defense against T. schoenleinii, and suggest that manipulating NLRP3 signaling can be a novel approach for control of diseases caused by T. schoenleinii infection.
Subject(s)
Animals , Humans , Mice , Bone Marrow Cells , Cell Biology , Carrier Proteins , Metabolism , Caspase 1 , Metabolism , Cell Line , Dendritic Cells , Cell Biology , Metabolism , Microbiology , Enzyme Activation , Hot Temperature , Inflammasomes , Metabolism , Interleukin-1beta , Metabolism , Lysosomes , Metabolism , Monocytes , Cell Biology , Metabolism , Microbiology , NLR Family, Pyrin Domain-Containing 3 Protein , Potassium , Metabolism , Reactive Oxygen Species , Metabolism , Signal Transduction , Trichophyton , PhysiologyABSTRACT
The complete nucleotide sequence of a cDNA clone encoding weever ribosomal protein L8, WeevL8, is described here. The WeevL8 cDNA has 848 nucleotides in full length and encodes a 257 amino-acid protein with a calculated molecular mass of 28.02 kDa. Two conserved domains have been identified in WEEVL8. It was concluded fromsequence alignment that WeevL8 gene was quite conservative, consistent with its role as a house-keeping gene. A phylogenetic analysis made by L8 protein showed the similar phylogenetic relationship to that with 18s rDNA. The high similarity supports the notion that ribosomal protein L8 can also be used as phylogenetic criterion.
ABSTRACT
Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors belonging to the steroid receptor superfamily. Three PPAR isoforms, PPAR?, PPAR? (also known as PPAR?) and PPAR? have been found in the mouse. They can activate expression of many genes, including those involved in lipidmetabolism. PPAR? is ubiquitously expressed, but the level of expression differs markedly between different cell types. PPAR? is expressed in skeletal muscle at 10- and 50-fold higher levels compared with PPAR? and PPAR?, respectively. A role for PPAR? in skeletal muscle is to increase the genes expression with relation to oxidative metabolism. In order to determine the molecular mechanisms governing PPAR? gene expression in muscle, a 2 kb 5′ flanking region was cloned and analyzed. The DNA fragment is able to transcribe GFP in COS7 cells. Dual luciferase assay is used to quantify promoter activity. Deletion analysis of the 2 kb PPAR? promoter fragment in COS7 and NIH 3T3 cells shows that the proximal promoter sequence, nt -197 to +120, confers basal transcriptional activity of the mouse PPAR? gene. Computational analysis of putative cis-acting elements located within the ～2.0 kb mouse PPAR? 5′-flanking sequence was performed using the TRANSFAC database and MatInspector software and 4 potential MEF2A binding sites were found. And there is a potential binding site sharing 100% identity with positive element of MEF2A in the proximal promoter (nt -261). Co-transfection experiments of the PPAR? promoter reporter and pMEF2A expression plasmid (pMEF2A) showed that MEF2A significantly enhanced transcription activity of PPAR? promoter in NIH 3T3. Moreover, the enhancive effect depended on the concentration of plasmid pMEF2A transfected into cells. The results suggested that MEF2A may enhance transcription activity of the PPAR promoter in muscle cells.