Multi-Faceted Proteomic Characterization of Host Protein Complement of Rift Valley Fever Virus Virions and Identification of Specific Heat Shock Proteins, Including HSP90, as Important Viral Host Factors

Abstract

Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV). Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry) with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90), as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

Annexins in Translational Research: HIDDEN Treasures to Be Found

“…In addition to IAV, AnxA1 is found associated with several other viruses [114][115][116][117][118][119][120][121][122]. Interestingly, no indications so far suggest that the viruses rely on its immune-modulating capacity to facilitate virus entry, although the AnxA1 receptor FPR2 is involved in IAV replication [123].…”

Emerging functions as host cell factors – an encyclopedia of annexin-pathogen interactions

“…Annexin A1 (AnxA1) is one of the most famous family members and there is a wealth of information on its protective anti-inflammatory and proresolving effects (Perretti and D'Acquisto, 2009 (Kattenhorn et al, 2004;Dry et al, 2008;Loret et al, 2008;Vidick et al, 2013), human immunodeficiency virus type 1 (HIV-1) (Chertova et al, 2006), vesicular stomatitis virus (VSV) (Moerdyk-Schauwecker et al, 2009, Rift Valley fever virus (Nuss et al, 2014) and IAV (Shaw et al, 2008), and recent evidence points to a function of the AnxA1 receptor FPR2 in IAV replication (Tcherniuk et al, 2016). AnxA2 is a component of herpesviruses (Wright et al, 1994(Wright et al, , 1995Varnum et al, 2004;Zhu et al, 2005;Dry et al, 2008;Loret et al, 2008;Gershom et al, 2012;Vidick et al, 2013), IAV (LeBouder et al, 2008;Shaw et al, 2008;Liu et al, 2012), HIV-1 (Chertova et al, 2006), human papilloma virus (HPV) type 16 (Woodham et al, 2012), hepatitis C virus (HCV) type 1 (Backes et al, 2010), VSV (Moerdyk-Schauwecker et al, 2009, vaccinia virus (Chung et al, 2006), Rift Valley fever virus (Nuss et al, 2014) and Newcastle disease virus (Ren et al, 2012). AnxA5 is associated with herpes simplex virus (HSV) type 1 (Loret et al, 2008), HIV-1 (Chertova et al, 2006), VSV (Moerdyk-Schauwecker et al, 2009, Rift Valley fever virus (Nuss et al, 2014), and IAV (Shaw et al, 2008).…”

“…AnxA2 is a component of herpesviruses (Wright et al, 1994(Wright et al, , 1995Varnum et al, 2004;Zhu et al, 2005;Dry et al, 2008;Loret et al, 2008;Gershom et al, 2012;Vidick et al, 2013), IAV (LeBouder et al, 2008;Shaw et al, 2008;Liu et al, 2012), HIV-1 (Chertova et al, 2006), human papilloma virus (HPV) type 16 (Woodham et al, 2012), hepatitis C virus (HCV) type 1 (Backes et al, 2010), VSV (Moerdyk-Schauwecker et al, 2009, vaccinia virus (Chung et al, 2006), Rift Valley fever virus (Nuss et al, 2014) and Newcastle disease virus (Ren et al, 2012). AnxA5 is associated with herpes simplex virus (HSV) type 1 (Loret et al, 2008), HIV-1 (Chertova et al, 2006), VSV (Moerdyk-Schauwecker et al, 2009, Rift Valley fever virus (Nuss et al, 2014), and IAV (Shaw et al, 2008). How and at which stage in the virus infection cycle annexins are acquired remains so far unclear (which Gershom et al, 2012Wright et al, 1994Wright et al, 1995;Pietropaolo and Compton 1997;Pietropaolo and Compton 1999;Raynor et al, 1999;Varnum et al, 2004;Derry et al, 2007 generally holds true for virus-embedded host cell proteins), and the association might simply reflect the nature of the specialized membrane domains where viral assembly and budding take place.…”

Aspirin-induced heat stress resistance in chicken myocardial cells can be suppressed by BAPTA-AM in vitro

“…First used as a Ca 2+ -chelating agent, BAPTA-AM was recently shown to inhibit some HSPs (Kaida et al 1999;Kiang et al 2000;Tokuda et al 2002). In some novel studies, BAPTA-AM was even used as a broad-spectrum HSP inhibitor, with good results being obtained (Kiang 2003;Nuss et al 2014). Accordingly, in this study, we evaluated the heat stress injury and assessed the anti-injury effects of aspirin with and without the addition of BAPTA-AM as an HSP inhibitor.…”