Human Cytomegalovirus Induces the Expression of the AMPKa2 Subunit To Drive Glycolytic Activation and Support Productive Viral Infection

Abstract

Human Cytomegalovirus (HCMV) infection modulates cellular metabolism to support viral replication. Calcium/calmodulin-dependent kinase kinase (CaMKK) and AMP-activated protein kinase (AMPK) regulate metabolic activation and have been found to be important for successful HCMV infection. Here, we explored the contributions that specific CaMKK isoforms and AMPK subunit isoforms make toward HCMV infection. Our results indicate that various CaMKK and AMPK isoforms contribute to infection in unique ways. For example, CaMKK1 is important for HCMV infection at a low multiplicity of infection, but is dispensable for AMPK activation at the earliest times of infection, which our data suggest is more reliant on CaMKK2. Our results also indicate that HCMV specifically induces the expression of the non-ubiquitous AMPKa2 catalytic subunit, found to be important for both HCMV-mediated glycolytic activation and high titer infection. Further, we find that AMPK-mediated glycolytic activation is important for infection, as overexpression of GLUT4, the high capacity glucose transporter, partially rescues viral replication in the face of AMPK inhibition. Collectively, our data indicate that HCMV infection selectively induces the expression of specific metabolic regulatory kinases, relying on their activity to support glycolytic activation and productive infection. IMPORTANCE Viruses are obligate parasites that depend on the host cell to provide the energy and molecular building blocks to mass produce infectious viral progeny. The processes that govern viral modulation of cellular resources have emerged as critical for successful infection. Here, we find that HCMV depends on two kinase isoforms to support infection, CaMKK1 and AMPKa2. We find that HCMV specifically induces expression of the AMPKa2 subunit to induce metabolic activation and drive robust viral replication. These results suggest that HCMV has evolved mechanisms to target specific metabolic regulatory kinase subunits to support productive infection, thereby providing insight into how HCMV hijacks cellular metabolism for its replication, and sheds light on potential viral therapeutic vulnerabilities.

The antiviral state has shaped the CpG composition of the vertebrate interferome to avoid self-targeting

“…As both CAMKK1 and KDM6B are necessary for efficient herpesvirus replication or reactivation [ 43 , 44 ], the reduced levels of these gene products could potentially inhibit viral replication. In support of this notion, ablation of CAMKK1 expression has recently been shown to inhibit cytomegalovirus replication in vitro [ 45 ]. In contrast, the observed ability of IFN to inhibit Indiana vesiculovirus (VSV) infection in the absence of ZAP indicates that ZAP-targeted IRGs are not essential for a functional antiviral state.…”

Abnormal glucose metabolism in virus associated sepsis

“…However, when AMPK is inhibited, HCMV replication is partially saved, emphasizing the GLUT4 transporter’s role in AMPK-mediated HCMV infection. In summary, glycolytic activation is a major part of HCMV infection, and further exploration of how HCMV reprograms cell metabolism is beneficial to reveal potential viral treatment options ( Dunn et al., 2020 ).…”

Multifaceted Role of AMPK in Viral Infections

“…On the other hand, in HCMV, AMPK activation is beneficial for the virus. It induces the expression of the AMPKα2 catalytic subunit, leading to glycolytic activation and supporting productive viral infection [ 138 ]. In CVB3 infection, IFN-β modulates glucose metabolism through a PI3K/Akt-dependent mechanism and decreases the phosphorylation of AMPK.…”