Coxsackievirus can exploit LC3 in both autophagy-dependent and -independent manners in vivo

Abstract

RNA viruses modify intracellular membranes to produce replication scaffolds. In pancreatic cells, coxsackievirus B3 (CVB3) hijacks membranes from the autophagy pathway, and in vivo disruption of acinar cell autophagy dramatically delays CVB3 replication. This is reversed by expression of GFP-LC3, indicating that CVB3 may acquire membranes from an alternative, autophagy-independent, source(s). Herein, using 3 recombinant CVB3s (rCVB3s) encoding different proteins (proLC3, proLC3 G120A , or ATG4B C74A ), we show that CVB3 is, indeed, flexible in its utilization of cellular membranes. When compared with a control rCVB3, all 3 viruses replicated to high titers in vivo, and caused severe pancreatitis. Most importantly, each virus appeared to subvert membranes in a unique manner. The proLC3 virus produced a large quantity of LC3-I which binds to phosphatidylethanolamine (PE), affording access to the autophagy pathway. The proLC3 G120A protein cannot attach to PE, and instead binds to the ER-resident protein SEL1L, potentially providing an autophagy-independent source of membranes. Finally, the ATG4B C74A protein sequestered host cell LC3-I, causing accumulation of immature phagophores, and massive membrane rearrangement. Taken together, our data indicate that some RNA viruses can exploit a variety of different intracellular membranes, potentially maximizing their replication in each of the diverse cell types that they infect in vivo.

Manipulation of autophagy by (+) RNA viruses

“…A link between autophagosomes and virus-induced vesicles was proposed by George Palade by EM imaging of poliovirus containing vesicles that resembled autophagosomal membranes [6]. Over the past few decades, a growing body of research has defined the critical role of this pathway in facilitating infection by numerous +RNA RNA viruses, including poliovirus (PV) [7,8], Coxsackievirus B3 (CVB3) [9,10], CVB4 [11], Enterovirus 71 (EV71) [12], Human rhinovirus (HRV) [13], Foot-and-mouth disease virus (FMDV) [14], encephalomyocarditis virus (EMCV) [15], Dengue virus (DENV) [16,17], Zika virus (ZIKV) [18,19], Hepatitis C virus (HCV) [20], Mouse hepatitic virus (MHV), Newcastle disease virus (NDV) [21], Severe and acute respiratory syndrome coronavirus (SARS-CoV) [22], Chikungunya virus (ChikV) [23], and Japanese encephalitis virus (JEV) [24]. In many of the above cases, pharmacological or genetic manipulation of autophagy in vitro confirmed an inhibition in replication and/or spread of these viruses, whereas induction of autophagy resulted in increased production of progeny virions [21,25].…”

Fat(al) attraction: Picornaviruses Usurp Lipid Transfer at Membrane Contact Sites to Create Replication Organelles

“…Other well-known human picornaviruses are the hepatitis A virus (Hepatovirus genus), which causes hepatitis, human parechovirus (Parechovirus genus), which causes respiratory illness, gastroenteritis, myocarditis and encephalitis, and aichivirus (Kobuvirus genus), which causes gastroenteritis. and -independent manner [26]. Yet, ROs are not mere remnants of the Golgi or constituents of the autophagy pathway, but instead are new virus-induced organelles with a unique protein and lipid composition (reviewed in [27]).…”

“…Notwithstanding, the observation that CVB3 can exploit LC3 in both autophagy-dependent and -independent manners, and can rearrange membranes and replicate in the absence of functional LC3 [26], indicates that enteroviruseslike TBSV [88] and perhaps many other +RNA virusescan utilize disparate host membranes and machinery to generate ROs, depending on availability in different cell types. Hence, findings in whichever experimental system may only represent part of the story in multicellular organisms with many different cell types.…”

Enteroviruses Remodel Autophagic Trafficking through Regulation of Host SNARE Proteins to Promote Virus Replication and Cell Exit

“…Previous work by our group has demonstrated that poliovirus 1 (PV) uses acidic amphisomes to promote virus replication and maturation (Richards and Jackson, 2012). Coxsackievirus B3 induces the autophagic pathway but may inhibit degradation of autophagic cargo (Alirezaei et al, 2015; Shi et al, 2014; Wong et al, 2008). We report here that EV-D68 induces autophagy signaling to benefit its replication and manipulates the autophagosomal SNAREs.…”