Scanning electron microscopic study of human neuroblastoma cells affected with Naegleria fowleri Thai strains

Abstract

In order to understand the pathogenesis of Naegleria fowleri in primary amoebic meningoencephalitis, the human neuroblastoma (SK-N-MC) and African green monkey kidney (Vero) cells were studied in vitro. Amoeba suspension in cell-culture medium was added to the confluent monolayer of SK-N-MC and Vero cells. The cytopathic activity of N. fowleri trophozoites in co-culture system was elucidated by scanning electron microscope at 3, 6, 9, 12, and 24 h. Two strains of N. fowleri displayed well-organized vigorous pseudopods in Nelson's medium at 37 degrees C. In co-culture, the target monolayer cells were damaged by two mechanisms, phagocytosis by vigorous pseudopods and engulfment by sucker-like apparatus. N. fowleri trophozoites produced amoebostomes only in co-culture with SK-N-MC cells. In contrast, we could not find such apparatus in the co-culture with Vero cells. The complete destruction time (100%) at 1:1 amoeba/cells ratio of SK-N-MC cells (1 day) was shorter than the Vero cells (12 days). In conclusion, SK-N-MC cells were confirmed to be a target model for studying neuropathogenesis of primary amoebic meningoencephalitis.

Neuroprotection Against Degeneration of SK-N-MC Cells Using Neuron Growth Factor-Encapsulated Liposomes with Surface Cereport and Transferrin

“…As indicated in Figure c, the appearance of SK‐N‐MC cells was spheroidal with smooth exterior and several satellites, resembling neurons and axons. This structure was consistent with the morphology of normal SK‐N‐MC cells …”

“…This structure was consistent with the morphology of normal SK-N-MC cells. 42 Figure 7 shows the effect of the RMP-7 and Tf concentrations on the viability of HBMECs and HAs. As indicated in this figure, the treatment with RMP-7/Tf/NGF-liposomes slightly decreased the viability of HBMECs and HAs.…”

Biological characteristics and pathogenicity of Acanthamoeba

“…Petti found that trophozoites of 4 species of Acanthamoeba were cytopathic for cultured rat B 103 neuroblastoma cells and this process is achieved by destroying nerve cells through the food cup ( Pettit et al, 1996 ). The same process can be observed in the pathogenesis of other protozoa such as N. fowleri ( Tiewcharoen et al, 2008 ) and E. histolytica ( Miller et al, 2019 ). In the study of E. histolytica , it was found that there was pronounced actin polymerization within the amoebae at the site of human cell contact and ingested fragments were surrounded by polymerized actin, which indicates that trogocytosis is related to actin rearrangement ( Ralston et al, 2014 ).…”