Effect of human TNF-alpha on adult Schistosoma mansoni gene expression profile

ABSTRACT: Schistosoma mansoni is the major causative agent of schistosomiasis in the Americas. This parasite takes advantage from host signaling molecules such as cytokines and hormones to complete its development inside the host. TNF-α is the most important cytokine involved in the inflammatory response when cercaria, the infective stage, penetrates the human skin and a severe inflammatory response is started. In this work the authors describe the complete sequence of a possible TNF-α receptor in S. mansoni and detect that the receptor is most highly expressed in cercaria among all life cycle stages. In an attempt to mimic the situation at the site of skin penetration cercariae have been mechanically transformed in vitro into schistosomula and immediately exposed to human TNF-α . Exposure of these early schistosomula to the human hormone caused a large-scale change in the expression of parasite genes. Exposure of adult worms to human TNF-α caused gene expression changes as well, although the set of parasite altered genes was entirely different from that of schistosomula. This work increases the number of known signaling pathways of the parasite, and opens new perspectives into understanding the molecular components of TNF-α response as well as possibly interfering with parasite-host interaction. A platform previously designed by our group (PMID: 17517391) was used. 300 ng of RNA from adult schistosomes treated with TNF and its control were used for the hybridization. RNA amplification and labeling kit (Agilent Technologies) were used according to manufacturer´s instructions. Each sample was separately labeled with either Cy3 or Cy5. 825 ng cRNA from each amplification were used for hybridization; self-self experiments were performed. Washing and scanning procedures were according to the manufacturer´s instructions using GenePix 4000B scanner (Molecular Devices, Sunnyvale, CA, USA). Data was extracted using Feature Extraction software (Agilent Technologies). We calculated a virtual Log2 ratio between intensities of TNF-α Treated/Control, for each gene. With these ratios, we used two different approaches for SAM statistical analyses. SAM one-class approach was used to identify genes with sustained changes in their expression levels along the entire time period of observation (1 and 24 h); SAM two-class approach was used to identify genes with transient changes in their expression levels. In both cases, genes were considered differentially expressed at q-value � 0.05. Hierarchical clustering of selected genes was generated using Spotfire Decision Site software (TIBCO Software Inc., Palo Alto, CA, USA). For a gene that was represented in the array by multiple probes, we picked a single representative probe by selecting the probe with the highest absolute value of the Log2 ratio between intensities of TNF-α Treated/Control.

ORGANISM(S): Schistosoma mansoni

SUBMITTER: Sergio Verjovski-Almeida 

PROVIDER: E-GEOD-16261 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress