Prolonged STAT1 activation in neurons drives a pathological transcriptional response.

Neurons require physiological IFN-γ signaling to maintain central nervous system (CNS) homeostasis, however, pathological IFN-γ signaling can cause CNS pathologies. The downstream signaling mechanisms that cause these drastically different outcomes in neurons has not been well studied. We hypothesized that different levels of IFN-γ signaling in neurons results in differential activation of its downstream transcription factor, signal transducer and activator of transduction 1 (STAT1), causing varying outcomes. Using primary cortical neurons, we showed that physiological IFN-γ elicited brief and transient STAT1 activation, whereas pathological IFN-γ induced prolonged STAT1 activation, which primed the pathway to be more responsive to a subsequent IFN-γ challenge. This is an IFN-γ specific response, as other IFNs and cytokines did not elicit such STAT1 activation nor priming in neurons. Additionally, we did not see the same effect in microglia or astrocytes, suggesting this non-canonical IFN-γ/STAT1 signaling is unique to neurons. Prolonged STAT1 activation was facilitated by continuous janus kinase (JAK) activity, even in the absence of IFN-γ. Finally, although IFN-γ initially induced a canonical IFN-γ transcriptional response in neurons, pathological levels of IFN-γ caused long-term changes in synaptic pathway transcripts. Overall, these findings suggest that IFN-γ signaling occurs via non-canonical mechanisms in neurons, and differential STAT1 activation may explain how neurons have both homeostatic and pathological responses to IFN-γ signaling.

Enteroviruses: The role of receptors in viral pathogenesis.

Enteroviruses are among the most common viral infectious agents of humans and cause a broad spectrum of illness, which can range from mild and self-limiting to severe. Severe outcomes of enteroviral infections can include aseptic meningitis, bronchitis, acute liver failure, hand-foot-mouth disease (HFMD), hemorrhagic conjunctivitis, or acute flaccid myelitis and other paralytic syndromes. Enteroviruses initiate their replicative life cycles by attaching to a broad range of cell surface receptors, which play direct roles in the clinical outcomes of enteroviral infections. In this chapter, we review the transmission and viral life cycle of enteroviruses and discuss the diverse cell surface receptors that facilitate enterovirus attachment, entry, or genome release.

Breast Milk and Saliva for Postnatal Cyto†megalovirus Screening among Very Low Birth Weight Infants.

BACKGROUND: The optimal approach to managing postnatal cytomegalovirus disease (pCMV) among very low birth weight (VLBW) infants remains unknown. Methods to facilitate screening are needed. OBJECTIVE: Determine whether mother's milk and infant saliva can be used to reliably identify maternal cytomegalovirus (CMV) serostatus and detect infant pCMV acquisition. METHODS: This was a single-center, prospective cohort study of VLBW infants, and their mothers, born between 2017 and 2020. Maternal milk samples were tested for CMV immunoglobulin G (IgG) using a CMV glycoprotein B binding enzyme-linked immunosorbent assay and the results were compared with maternal serum CMV IgG results. Biweekly paired saliva and urine samples were collected from infants born to mothers with positive or unknown CMV serostatus. Saliva samples were tested for CMV DNA by quantitative real-time polymerase chain reaction (PCR) and compared with urine CMV qualitative PCR results obtained from a clinical laboratory. RESULTS: Among 108 infants without congenital CMV included in the study, 10 (9%) acquired pCMV. Both milk and blood CMV serology results were available for 70 mothers. Maternal milk antibody testing had a sensitivity of 97.2% (95% CI: 85.5-99.9%) and specificity of 91.2% (95% CI: 76.3-98.1%) in establishing CMV serostatus. Paired serially collected saliva and urine samples (n = 203) were available for 66 infants. Saliva PCR had a sensitivity of 30.0% (95% CI: 6.7-65.2%) and specificity of 92.7% (95% CI: 88.1-96.0%) in detecting pCMV acquisition. CONCLUSIONS: Maternal breast milk is a reliable alternative sample to determine CMV serostatus. Serial testing of infant saliva was not adequately sensitive for identifying pCMV acquisition in preterm infants.