Immune Transcriptome of Cells Infected with Enterovirus Strains Obtained from Cases of Type 1 Diabetes

Abstract

Enterovirus (EV) infection of insulin-producing pancreatic beta cells is associated with type 1 diabetes (T1D), but little is known about the mechanisms that lead the virus to cause a persistent infection and, possibly, to induce beta cell autoimmunity. A cell line susceptible to most enterovirus types was infected with EV isolates from cases of T1D and, for comparison, with a replication-competent strain of coxsackievirus B3. The transcription of immune-related genes and secretion of cytokines was evaluated in infected vs. uninfected cells. Acutely infected cells showed the preserved transcription of type I interferon (IFN) pathways and the enhanced transcription/secretion of IL6, IL8, LIF, MCP1, and TGFB1. On the other hand, infection by defective EV strains obtained from diabetic subjects suppressed IFN pathways and the transcription of most cytokines, while enhancing the expression of IL8, IL18, IL32, and MCP1. IL18 and IL32 are known for their pathogenic role in autoimmune diabetes. Thus, the cytokine profile of AV3 cells infected by diabetes-derived EV strains closely matches that observed in patients at the early stages of T1D. The concordance of our results with clinically verified information reinforces the hypothesis that the immune changes observed in type 1 diabetic patients are due to a hardly noticeable virus infection.

Immune Transcriptome of Cells Infected with Enterovirus Strains Obtained from Cases of Autoimmune Thyroid Disease

“…Following a published method [ 9 ], a mixture of five EV-permissive cell lines that express a wide variety of EV receptors was used for virus isolation. The AV3, RD, 1.1B4, VC3 and HEK293 cell lines (obtained from the European Collection of Authenticated Cell Cultures, ECACC) were cultured at 37 °C in air with 5% CO 2 using the DMEM/F12 medium supplemented with L-glutamine, heat-inactivated 10% fetal bovine serum (FBS), penicillin/streptomycin.…”

“…While an acute infection causes cell death and is usually symptomatic, a persistent low-grade infection is subclinical and may excite prolonged responses in infected cells that may gradually activate immune pathways [ 9 ].…”

“…In pancreatic islets, the demonstrated upregulation of HLA class I and STAT1 genes likely reflects an enduring antiviral response [ 14 ]. In fact, transcriptome analysis of the cells infected with EV strains from T1D cases show that distinct immune pathways are deregulated [ 9 ].…”

“…Non-infected AV3 cells were used for comparison. The results indicate that infection by AITD-derived EV strains curbs antiviral defenses and activates pathways potentially capable of initiating organ-specific autoimmunity [ 9 , 16 ].…”

Type 1 Diabetes: Interferons and the Aftermath of Pancreatic Beta-Cell Enteroviral Infection

“…Among the infectious agents, many studies have implicated infection by enteroviruses (EVs), but it has not been established which EV serotypes (among the more than 100 known) are involved. The available evidence supports infection by various strains of the Coxsackievirus B (CVB) and some Echoviruses [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], but various other viruses including rubella, mumps, reoviruses, parvoviruses and cytomegalovirus have also been linked to T1D [ 22 , 23 ]. However, evidence for the implication of the latter viruses in T1D has been challenged on the basis of a weak link and/or irreproducibility of the association [ 24 ].…”