JNK and PI3k/Akt signaling pathways are required for establishing persistent SARS-CoV infection in Vero E6 cells

Abstract

Persistence was established after most of the SARS-CoV-infected Vero E6 cells died. RNA of the defective interfering virus was not observed in the persistently infected cells by Northern blot analysis. SARS-CoV diluted to 2 PFU failed to establish persistence, suggesting that some particular viruses in the seed virus did not induce persistent infection. Interestingly, a viral receptor, angiotensin converting enzyme (ACE)-2, was down-regulated in persistently infected cells. G418-selected clones established from parent Vero E6 cells, which were transfected with a plasmid containing the neomycin resistance gene, were infected with SARS-CoV, resulting in a potential cell population capable of persistence in Vero E6 cells. Our previous studies demonstrated that signaling pathways of extracellular signal-related kinase (ERK1/2), c-Jun N-terminal protein kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3'-kinase (PI3K)/Akt were activated in SARS-CoV-infected Vero E6 cells. Previous studies also showed that the activation of p38 MAPK by viral infection-induced apoptosis, and a weak activation of Akt was not sufficient to protect from apoptosis. In the present study, we showed that the inhibitors of JNK and PI3K/Akt inhibited the establishment of persistence, but those of MAPK/ERK kinase (MEK; as an inhibitor for ERK1/2) and p38 MAPK did not. These results indicated that two signaling pathways of JNK and PI3K/Akt were important for the establishment of persistence in Vero E6 cells.

Uses for JNK: the Many and Varied Substrates of the c-Jun N-Terminal Kinases

“…There is also an increasing body of literature showing that JNK activation follows bacterial, fungal, prion, parasitic, or viral infections. Under these circumstances, JNK activation may influence important cellular consequences, such as alterations in gene expression (1,53,59,162,167,176,199,294,325,326,346), cell death (58,89,137,139,169,193,243,293), viral replication, persistent infection or progeny release (215,224,251,260), or altered cellular proliferation (178). The exact mechanism of JNK activation under each of these circumstances remains to be elucidated fully, although there may be involvement of Toll-like receptors, direct pathway modulation through interaction with upstream protein regulators, or the activation following an ER stress response (79,87,110,124,143,191,253,261,279,294,312).…”

SP600125 inhibits Orthopoxviruses replication in a JNK1/2 -independent manner: Implication as a potential antipoxviral

“…Furthermore, the use of signal transduction pathways modulators, either singly (Yang et al, 2005a,b;Reeves et al, 2005) or in combination, could be the most appropriate therapeutic strategy. In fact, it has been shown that SP600125 used together with inhibitors of phosphatidylinositol 3-kinase/Akt prevented the establishment of persistent SARS-CoV infection (Mizutani et al, 2005).…”

Receptor tyrosine kinase inhibitors block proliferation of TGEV mainly through p38 mitogen-activated protein kinase pathways

“…W. Dong, et al Antiviral Research 173 (2020) 104651 2015; Kindrachuk et al, 2015;Lee et al, 2016;Mizutani et al, 2005). Nevertheless, no studies to date have focused on detecting global phosphorylation events in host cells during CoV infection.…”

“…Yang et al found that PEDV infection stimulated the activation of EGFR and its downstream STAT3 cascade, which increased viral infection by negatively regulating type I interferon (IFN-I) signaling (Yang et al, 2018). The ERK/MAPK and PI3K/AKT/mTOR signaling responses play important roles in MERS-CoV infection (Kindrachuk et al, 2015), and JNK and phosphatidylinositol 3′-kinase (PI3K)/Akt are required for establishing persistent SARS-CoV infection in Vero E6 cells (Mizutani et al, 2005). Our phosphoproteomic analysis found that TGEV infection enhanced (A and E) Effect of inhibitors on viral yields.…”

“…RTKs are the primary mediators of many signals and control many downstream cascades, including phosphoinositide 3-kinase (PI3K), MAPK and Ca2 + pathways (Schlessinger, 2000). Several studies have shown that phosphoinositide 3-kinase (PI3K) signaling and STAT3 cascades, which are downstream of RTKs, play important roles in the life cycle of CoV (Hu et al, 2016;Kindrachuk et al, 2015;Mizutani et al, 2005;Yang et al, 2018). Further studies are required to explore whether these downstream cascades are involved in the inhibitory activity of A9 against TGEV replication.…”