Extracellular Vesicle Activation of Latent HIV-1 Is Driven by EV-Associated c-Src and Cellular SRC-1 via the PI3K/AKT/mTOR Pathway

Abstract

HIV-1 is a global health crisis that has infected more than 37 million people. Latent reservoirs throughout the body are a major hurdle when it comes to eradicating the virus. In our previous study, we found that exosomes, a type of extracellular vesicle (EV), from uninfected cells activate the transcription of HIV-1 in latent infected cells, regardless of combination antiretroviral therapy (cART). In this study, we investigated the specific mechanism behind the EV activation of latent HIV-1. We found that phosphorylated c-Src is present in EVs of various cell lines and has the ability to activate downstream proteins such as EGFR, initiating a signal cascade. EGFR is then able to activate the PI3K/AKT/mTOR pathway, resulting in the activation of STAT3 and SRC-1, culminating in the reversal of HIV-1 latency. This was verified by examining levels of HIV-1 TAR, genomic RNA and HIV-1 Gag p24 protein in cell lines and primary cells. We found that EVs containing c-Src rescued HIV-1 despite the presence of inhibitors, validating the importance of EV-associated c-Src in latent HIV-1 activation. Lastly, we discovered an increased recruitment of p300 and NF-κB in the nucleus of EV-treated infected cells. Collectively, our data suggest that EV-associated c-Src is able to activate latent HIV-1 via the PI3K/AKT/mTOR pathway and SRC-1/p300-driven chromatin remodeling. These findings could aid in designing new strategies to prevent the reactivation of latent HIV-1 in patients under cART.

Extracellular Vesicles in HTLV-1 Communication: The Story of an Invisible Messenger

“…It has been shown that HIV-1 infection promotes the release of EVs containing viral molecules and host components from the infected cells (e.g., monocytes, macrophages, dendritic cells, and T cells) [ 87 , 97 , 98 ], pointing to the essential role of EVs in viral spread. For instance, EVs derived from an uninfected T-cell line (i.e., CEM cells) were shown to reverse latency in HIV-1-infected cells in a process mediated by EV-associated to a non-receptor tyrosine kinase (c-Src) [ 99 , 100 ]. This kinase is involved in NF-kB signaling pathways, involved in cellular proliferation, differentiation, motility, and angiogenesis.…”

HIV-1 Latency and Viral Reservoirs: Existing Reversal Approaches and Potential Technologies, Targets, and Pathways Involved in HIV Latency Studies

“…As described previously, TAR RNA is essential for HIV Tat and protein kinase(s) RNA-activated (PKR) binding, however, the TAR miRNA binds to TLR7/TLR8, but not PKR [ 167 ]. Coculturing exosomal vesicles containing Tat, TAR RNA, TAR miRNA, and a newly found TAR-gag RNA induced IL-6, TNFβ, NF-κB pathways, cytokine production, and overall cellular activation of the recipient/neighbor cells, ultimately causing latency reversion [ 167 , 168 , 170 , 171 ]. These TAR RNA-containing exosomes also induced cancer-cell proliferation and progression by affecting expression of proto-oncogenes and TLR3 inducible genes, which reduced apoptosis in neighboring latency-reversing cells by lowering Bim and CDK9 protein levels [ 166 , 172 ].…”

Extracellular Vesicles in Viral Infections: Two Sides of the Same Coin?

“…EVs facilitate viral transmission HSV-1 (Bello-Morales and López-Guerrero, 2020), KSHV (Chen et al, 2020)., NDV (Zhou C. et al, 2019), PRRSV (Wang et al, 2017), enterovirus 71 (Gu et al, 2020), HCV (Bukong et al, 2014), HIV (Kadiu et al, 2012), SFTS (Silvas et al, 2016) Viral RNAs/proteins inside EVs Coronavirus (Maeda et al, 1999), EBV (Keryer-Bibens et al, 2006), HCV (Kouwaki et al, 2017)., HTLV-1, (Jaworski et al, 2014), RVFV (Ahsan et al, 2016), ZIKV (Zhou W. et al, 2019;Martıńez-Rojas et al, 2020) Infectious virus-like particles/cloaked virions inside EVs DENV (Reyes-Ruiz et al, 2019), enterovirus 71 (Gu et al, 2020), HCV (Bartosch et al, 2003;Timpe et al, 2008) Transfer of infective RNA through EVs withouth complete viral particles HCV (Longatti et al, 2015), FMDV (Zhang et al, 2019), EVs turn cells more permissive to infection, membrane/receptor modulation HIV (Arenaccio et al, 2014;Dubrovsky et al, 2020), Rhinovirus (Miura, 2019) Host molecules in EVs facilitate viral stability and replication in recipient cells HBV , HCV (Bukong et al, 2014;Altan-Bonnet, 2016), HIV (Arenaccio et al, 2014;Ranjit et al, 2020) Amplification of EV production ZIKV (Zhou W. et al, 2019) EVs from uninfected cells can activate latent viruses HIV (Barclay et al, 2020) EVS RELATED TO IMMUNE RESPONSES…”

“…Mediate chemoresistance HBV (Liu D. et al, 2019) Mediate autoimmunity/transplant rejection respiratory viruses (Gunasekaran et al, 2020). EVs involved in viral latency/persistant infections HIV (Olivetta et al, 2019;Barclay et al, 2020), HCV (Ashraf Malik et al, 2019), Thrombosis induction SARS CoV-2 (Inal, 2020a), Nomura et al, 2020 induced signaling as an immune evasion strategy (Florentin et al, 2012). A recently explored area gaining attention involves the transfer of ISGs through EVs.…”

“…Nef can induce cell death when delivered to bystander TCD4+ cells (Lenassi et al, 2010) and the degradation of the viral receptors CD4 and MHC-1 (an important molecule that presents viral antigens to the immune system) through the action of Nefinteracting protein B-cop (Schaefer et al, 2008). In addition, EVs secreted by uninfected cells can activate the transcription of latent viruses in HIV-1-infected cells through cellular SRC-1 and the PI3K/AKT/mTOR pathway (Barclay et al, 2020).…”