{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T07:54:10Z","timestamp":1778226850518,"version":"3.51.4"},"reference-count":34,"publisher":"Springer Science and Business Media LLC","issue":"1","content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Parasites Vectors"],"published-print":{"date-parts":[[2012,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p><jats:italic>Acanthamoeba<\/jats:italic>species are the causative agents of fatal granulomatous encephalitis in humans. Haematogenous spread is thought to be a primary step, followed by blood\u2013brain barrier penetration, in the transmission of<jats:italic>Acanthmaoeba<\/jats:italic>into the central nervous system, but the associated molecular mechanisms remain unclear. Here, we evaluated the role of Src, a non-receptor protein tyrosine kinase in the biology and pathogenesis of<jats:italic>Acanthamoeba<\/jats:italic>.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Amoebistatic and amoebicidal assays were performed by incubating amoeba in the presence of Src kinase-selective inhibitor, PP2 (4-amino-5-(4-chlorophenyl)-7-(<jats:italic>t<\/jats:italic>-butyl)pyrazolo[3,4-<jats:italic>d<\/jats:italic>]pyrimidine) and its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-<jats:italic>d<\/jats:italic>]pyrimidine). Using this inhibitor, the role of Src kinase in<jats:italic>A. castellanii<\/jats:italic>interactions with<jats:italic>Escherichia coli<\/jats:italic>was determined. Zymographic assays were performed to study effects of Src kinase on extracellular proteolytic activities of<jats:italic>A. castellanii<\/jats:italic>. The human brain microvascular endothelial cells were used to determine the effects of Src kinase on<jats:italic>A. castellanii<\/jats:italic>adhesion to and cytotoxicity of host cells.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Inhibition of Src kinase using a specific inhibitor, PP2 (4-amino-5-(4 chlorophenyl)-7-(<jats:italic>t<\/jats:italic>-butyl)pyrazolo [3,4-<jats:italic>d<\/jats:italic>] pyrimidine) but not its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-<jats:italic>d<\/jats:italic>] pyrimidine), had detrimental effects on the growth of<jats:italic>A. castellanii<\/jats:italic>(keratitis isolate, belonging to the T4 genotype). Interestingly, inhibition of Src kinase hampered the phagocytic ability of<jats:italic>A. castellanii<\/jats:italic>, as measured by the uptake of non-invasive bacteria, but, on the contrary, invasion by pathogenic bacteria was enhanced. Zymographic assays revealed that inhibition of Src kinases reduced extracellular protease activities of<jats:italic>A. castellanii<\/jats:italic>. Src kinase inhibition had no significant effect on<jats:italic>A. castellanii<\/jats:italic>binding to and cytotoxicity of primary human brain microvascular endothelial cells, which constitute the blood\u2013brain barrier.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>For the first time, these findings demonstrated that Src kinase is involved in<jats:italic>A. castellanii<\/jats:italic>proliferation, protease secretions and phagocytic properties. Conversely, invasion of<jats:italic>Acanthamoeba<\/jats:italic>by pathogenic bacteria was stimulated by Src kinase inhibition.<\/jats:p><\/jats:sec>","DOI":"10.1186\/1756-3305-5-112","type":"journal-article","created":{"date-parts":[[2012,6,14]],"date-time":"2012-06-14T10:43:04Z","timestamp":1339670584000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["The role of Src kinase in the biology and pathogenesis of Acanthamoeba castellanii"],"prefix":"10.1186","volume":"5","author":[{"given":"Ruqaiyyah","family":"Siddiqui","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junaid","family":"Iqbal","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marie-jos\u00e9e","family":"Maugueret","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Naveed Ahmed","family":"Khan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2012,6,7]]},"reference":[{"key":"628_CR1","doi-asserted-by":"publisher","first-page":"1689","DOI":"10.1128\/JCM.43.4.1689-1693.2005","volume":"43","author":"GC Booton","year":"2005","unstructured":"Booton GC, Visvesvara GS, Byers TJ, Kelly DJ, Fuerst PA: Identification and distribution ofAcanthamoebaspecies genotypes associated with nonkeratitis infections. 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