The heat shock protein 70 (Hsp70) family of chaperones is essential for rhinovirus replication

Abstract

2.Rhinoviruses (RVs) are the predominant cause of the common cold and a major trigger of acute asthma exacerbations. Yet, unlike related enteroviruses such as poliovirus (PV) and enterovirus A71 (EV-A71), no approved vaccines or antivirals exist. Because enteroviruses depend heavily on host factors for replication, cellular proteins that support the replication of multiple enteroviruses have emerged as attractive broad-spectrum antiviral targets that may offer a higher barrier to resistance than virus-targeted therapies. The 70-kDa heat shock protein (Hsp70) family, a highly conserved class of molecular chaperones, is required for the replication of several enteroviruses, including EV-A71 and coxsackievirus A16, but whether RVs share this dependency was unknown. Here, we show that two mechanistically distinct small-molecule inhibitors of the Hsp70 family abolish replication of RV-A16, a clinically relevant RV type widely used in asthma research. Using siRNA knockdown, we demonstrate a role for HSPA8, the major constitutively expressed Hsp70 isoform, in RV replication. We further demonstrate that Hsp70 activity is indispensable for viral translation, identifying this as a key Hsp70-dependent step in the RV replication cycle. Together, these findings establish Hsp70 chaperones as essential host factors for RV replication and strengthen the rationale for targeting them as a broad-spectrum antiviral strategy. 3. Impact statementRhinoviruses are the predominant cause of the common cold and major triggers of exacerbations in people with asthma and chronic obstructive pulmonary disease, yet no licensed antiviral therapies exist. Although several enteroviruses are known to require Hsp70 chaperones for replication, whether rhinoviruses share this dependence was unknown. Here, we address this gap by demonstrating that Hsp70 chaperones are essential host factors for rhinovirus replication and are required for viral translation. These findings advance our understanding of how rhinoviruses exploit the host cell machinery and broaden the evidence supporting Hsp70 chaperones as potential antiviral targets across the Enterovirus genus. As host-targeted therapies may be less vulnerable to resistance than direct-acting antivirals, these findings represent an important step towards the development of urgently needed anti-rhinoviral therapeutics and will be of interest to virologists, respiratory clinicians and antiviral drug developers.