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Hancks, D. C.

Publications and source records attributed to Hancks, D. C..

3 recordsLinked to original sources

Mitochondrial perturbation adapts the proteome from early to advanced immune responses

Dysregulated immunity, a hallmark of many human diseases, co-occurs with mitochondrial dysfunction and is commonly associated with misprimed primary immune signaling. While transcriptionally well-characterized, the impact of mitochondria on the host response at the protein level is less clear. Using in vitro and in vivo approaches including proteotranscriptomics, our data suggest that OXPHOS promotes expression of early, cell autonomous immune proteins whereas mitochondrial perturbation favors mediators of cell extrinsic responses like inflammation. This response is independent of immune cues, time-dependent, conserved, and occurs across tissues in mouse models of mitochondrial dysfunction. These data illustrate unappreciated roles for mitochondrial state in adapting host responses at the protein level, which have implications for complex disease etiology and the ancestral origins for eukaryotic immune sensing.

immunology↗

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-g induced IRF1

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-{gamma}/glucose and increased IFITM3 in galactose by IFN- and IFN-{gamma}. In agreement with a hardwired response, glucose/galactose regulation of interferon-{gamma} induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-{gamma} induced IRF1 levels to that of glucose/interferon-{gamma}. Glucose/interferon-{gamma} decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-{gamma} priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

microbiology↗

Viral piracy of host RNA phosphatase DUSP11 by avipoxviruses

Proper recognition of viral pathogens is an essential part of the innate immune response. A common viral replicative intermediate and chemical signal that cells use to identify pathogens is the presence of a triphosphorylated 5 end (5ppp) RNA, which activates the cytosolic RNA sensor RIG-I and initiates downstream antiviral signaling. While 5pppRNA generated by viral RNA-dependent RNA polymerases (RdRps) can be a potent activator of the immune response, endogenous RNA polymerase III (RNAPIII) transcripts can retain the 5pppRNA generated during transcription and induce a RIG-I-mediated immune response. We have previously shown that host RNA triphosphatase dual-specificity phosphatase 11 (DUSP11) can act on both host and viral RNAs, altering their levels and reducing their ability to induce RIG-I activation. Our previous work explored how artificially altered DUSP11 can impact immune activation, prompting further exploration into natural contexts of altered DUSP11. Here, we have identified viral DUSP11 homologs (vDUSP11s) present in some avipoxviruses. Consistent with the known functions of endogenous DUSP11, we have shown that expression of vDUSP11s: 1) reduces levels of endogenous RNAPIII transcripts, 2) reduces a cells sensitivity to 5pppRNA-mediated immune activation, and 3) restores virus infection defects seen in the absence of DUSP11. Our results identify a virus-relevant context where DUSP11 activity has been co-opted to alter RNA metabolism and influence the outcome of infection.

molecular biology↗