Induction and inhibition of an apparent neuronal phenotype in Spodoptera frugiperda insect cells (Sf21) by chemical agents

Abstract

The goal of this research was to induce neuron-like properties in Sf21 cells, an insect ovarian cell line, which could lead to a new high-throughput insecticide screening method and a way to mass produce insect neuronal material for basic research. This study applied differentiation agents to produce viable neuron-like cells. In the presence of the molting hormone 20-hydroxyecdysone (20-HE), or insulin, in the growth medium, a maximum of ca. 30 % of Sf21 cells expressed an apparent neuronal morphology of unipolar, bipolar, or multipolar axon-like processes within 2-3 days. Maximal differentiation occurred after 2 days in the presence of 50 μM 20-HE or 3 days in 10 μM insulin. Both 20-HE and insulin displayed time- and concentration-dependent differentiation with biphasic curves, suggesting that two binding sites or processes were contributing to the observed effects. In addition, combinations of 20-HE and insulin produced apparent synergistic effects on differentiation. Caffeine, a central nervous system stimulant, inhibited induction of elongated processes by 20-HE and/or insulin, with an IC(50) of 9 nM for 20-HE, and the inhibition was incomplete, resulting in about one-quarter of the differentiated cells remaining, even at high concentrations (up to 1 mM). The ability to induce a neural phenotype simplifies the studies of insect cells, compared to either the use of primary nervous tissue or genetic engineering techniques. The presence of ion channels or receptors in the differentiated cells remains to be determined.

An Ixodes scapularis cell line with a predominantly neuron-like phenotype

“…In larval ticks, it may be that hemolymph factors are retained from the egg stage, when cells are rapidly differentiating, resulting in the similar phenotype observed for injected ISE6 cells. Future research will aim at developing an in vitro method of stimulating neuron-like ISE6 formation by chemical methods such as exposure to ecdysteroids and other hormones that regulate molting (Kurtti and Munderloh 1983; Jenson et al 2012). …”

ROLE OF SERUM AND ION CHANNEL BLOCK ON GROWTH AND HORMONALLY‐INDUCED DIFFERENTIATION OF Spodoptera frugiperda (Sf21) INSECT CELLS

“…Insulin treatment also induces a neuron‐like morphology (Jenson et al., ), but effects of blockers were not tested in that study. Morphological changes to Sf 21 cells occurred in the presence of 10 μM I, with greatest effect on day 3 (Fig.…”

“…Effects of control (0.1% DMSO) and 42 μM 20‐HE treatments on Sf 21 cells adapted to serum‐free and serum‐containing medium across days ( n = 3). Serum‐containing data are from previously published work (Jenson et al., ). Statistical analysis was performed using one‐way ANOVA ( P < 0.05) and a SNK multiple comparison posttest.…”

“…In lepidopteran cell lines, the concentration–response curves for this effect of 20‐HE had shallow slopes, and often two saturation plateaus, both evidence for two sites of action (Lynn and Oberlander, ; Jenson et al., ). Moreover, the growth of ecdysone‐induced processes was blocked by the antitubulin agents, vinblastine and colcemid, in Manduca sexta cell lines (Lynn and Oberlander, ) and by caffeine in Sf 21 cells (Jenson et al., ). Other changes induced by 20‐HE include changes in sugar uptake and chitin synthesis (Oberlander and Leach, ), increased enzymatic activity (Cherbas et al., ; Berger and Wyss, ; Cohen, ), and inhibition of cell proliferation and initiation of cell arrest (Giraudo et al., ).…”

Insecticide sensitivity of native chloride and sodium channels in a mosquito cell line

“…For cell number experiments, counts were performed using the methods of Jenson et al [9]. Briefly, an ocular grid (0.221 mm 2 ) was aligned with the corners of the scored lines on the flask so that the same places and area were counted each day.…”