In vivo and in vitro models of demyelinating disease of coronaviruses in primary explants of the rat CNS

Abstract

The coronaviruses, ubiquitous in mammals, including man, manifest serotype-related predeliction for different tissues. This presentation deals with specificity of the murine viscerotropic MHV3 and neurotropic JHMV for explanted cells from the CNS of newborn, inbred, Wistar-Furth rats. An unambiguous tropism of MHV3 for astrocytes and JHMV for oligodendrocytes is demonstrated. With the latter cell-virus interaction, relatively small differences in spatial density of oligodendrocytes influence profoundly the duration of persistence and virus yield. The in vitro temporal program of oligodendrocyte differentiation, monitored by induction of a myelin-related enzyme, 2':3'-cyclic nucleotide-3'-phosphohydrolase, corresponds to that occurring in vivo (F. A. McMorris, J. Neurochem. 41, 506-515, 1983). It is complete within 15-21 days and is coincident with the onset of insusceptibility to disease caused by JHMV. Experimental elevation of intracellular cyclic-AMP levels, presumed to reflect oligodendrocyte differentiation, likewise suppresses JHMV replication without affecting that of MHV3 in astrocytes. On the basis of these data it is concluded that in vitro interaction of JHMV with oligodendrocytes reflects accurately the in vivo host control over the tropism and expression of this virus, thereby effecting the progressive, demyelinative disease, process.

Several Rat Cell Lines Share a Common Defect in Their Inability to Internalize Murine Coronaviruses Efficiently

“…These effects can occur at the adsorption phase due to a deficiency in receptors (Tardieu et al, 1986;Boyle et al, 1987), at the uncoating stage by as yet undetermined mechanisms (Beushausen et al, 1987;Kooi et al, 1988) which may be related to the differentiation state of the cell (Beushausen & Dales, 1985;Beushausen, 1986;Beushausen et al, 1987) or at later stages during the spread of infection (Wilson & Dales, 1988) perhaps due to variations in proteolytic activity (Frana et al, 1985). In this report and in a previous one (Van Dinter & Flintoff, 1987) we demonstrate that internalization of bound virus can also be a stage at which host control can occur.…”

Viruses, Immunity, and Mental Disorders

“…As with RN2-2 cells, our observations on the tropism of JHMV and MHV-3 for specific glial cells in vitro emphasize that control is exerted by the host cell over virus expression (Beushausen and (Table 4), and virus is undetectable byl0 days post-inoculation. By contrast, at a twofold higher cell density of 2 x 10 5 cells/cm2, JHMV is produced at 100-to lOoo-fold greater titers and for extended periods (Table 4) (Beushausen and Dales, 1985).…”

“…Virus yields in the primary cultures of rat glial cells are profoundly reduced at the restrictive temperature of 39 SC (Beushausen and Dales, 1985). Coronavirus replication is also controlled by the state of glial cell differentiation.…”

“…b Virus titers were determined for the culture medium on L-2 monolayers as described by Lucas et al (1978). c Approximately 2.5 x 1()5 cells/cm 2 • d Approximately 1 ()5 cells/cm 2 • by JHMV (Table 5; Beushausen and Dales, 1985). Virus suppression is also correlated with the induction of differentiation in vitro by 1 mM N 6 ,0 2 ' -dibutyryladenosine 3': 5'cyclic monophosphate (dbcAMP) or compounds that increase intracellular levels of cAMP such as 7 11M papaverine, 50 11M forskolin, or 50 11M isoproterenol (Beushausen and Dales, 1985;S.…”

“…Beushausen and S. Dales, unpublished data). By contrast, modulation of cAMP levels in astrocytes has little or no short-term effect on MHV -3 replication (Beushausen and Dales, 1985). Although pretreatment of oligodendrocytes with 1 mM dbcAMP 48 hr before JHMV challenge totally inhibits replication, similar treatment once b Cultures were exposed to 1 mM dbcAMP in basal minimal essential medium.…”