The involvement of an integrin-like protein and protein kinase C in amoebic adhesion to fibronectin and amoebic cytotoxicity.
Adherence of a pathogen to the host cell is one of the critical steps in microbial infections. Naegleria fowleri, a causative agent of primary amoebic meningoencephalitis in humans, is expected to interact with extracellular components of the host, such as fibronectin, in a receptor-mediated mode. In this study, we investigated the interaction between N. fowleri and fibronectin to understand its cytopathology. In binding assays using immobilized fibronectin, the number of amoebae bound to fibronectin was increased compared to the controls, and was dependent on the amount of coated fibronectin present. A fibronectin binding protein of 60 kDa was found in extracts of N. fowleri. Western blot and immunolocalization assays using integrin alpha(5)/FnR antibodies showed that a 60 kDa protein reacted with the antibodies in extracts of N. fowleri, which was localized on the surface of N. fowleri. Preincubation of N. fowleri with the integrin antibodies significantly inhibited amoebic binding to fibronectin and cytotoxicity to the CHO cells. Additionally, protein kinase C activity was detected in the extract of N. fowleri. When N. fowleri was pretreated with protein kinase C activator or inhibitor, the abilities of amoebic adhesion to fibronectin and cytotoxicity to the host cells were markedly affected compared to untreated amoebae. These results suggest that an amoebic integrin-like receptor and protein kinase C play important roles in amoebic cellular processes in response to fibronectin.
Han
Kyu-Lee
KL
Department of Parasitology and Institute of Tropical Medicine, The Brain Korea 21 Project, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, 120-752 Seoul, Korea.
Lee
Hyun-Ju
HJ
Shin
Myeong Heon
MH
Shin
Ho-Joon
HJ
Im
Kyung-Il
KI
Park
Soon-Jung
SJ
D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion; D006224:Cricetinae; D005353:Fibronectins / Q000378:metabolism*; D005786:Gene Expression Regulation; D016023:Integrins / Q000378:metabolism*; D016848:Naegleria fowleri / Q000472:pathogenicity* / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction
D005353:Fibronectins; D016023:Integrins; D011493:Protein Kinase C