Prostacyclin release and cytotoxicity of peritoneal cells are inversely related in pregnant and non-pregnant mice infected with herpes simplex virus

Lipid alternations in the plasma of COVID-19 patients with various clinical presentations

Background

COVID-19 is a highly infectious respiratory disease that can manifest in various clinical presentations. Although many studies have reported the lipidomic signature of COVID-19, the molecular changes in asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals remain elusive.

Methods

This study combined a comprehensive lipidomic analysis of 220 plasma samples from 166 subjects: 62 healthy controls, 16 asymptomatic infections, and 88 COVID-19 patients. We quantified 732 lipids separately in this cohort. We performed a difference analysis, validated with machine learning models, and also performed GO and KEGG pathway enrichment analysis using differential lipids from different control groups.

Results

We found 175 differentially expressed lipids associated with SASR-CoV-2 infection, disease severity, and viral persistence in patients with COVID-19. PC (O-20:1/20:1), PC (O-20:1/20:0), and PC (O-18:0/18:1) better distinguished asymptomatic infected individuals from normal individuals. Furthermore, some patients tested positive for SARS-CoV-2 nucleic acid by RT-PCR but did not become negative for a longer period of time (≥60 days, designated here as long-term nucleic acid test positive, LTNP), whereas other patients became negative for viral nucleic acid in a shorter period of time (≤45 days, designated as short-term nucleic acid test positive, STNP). We have found that TG (14:1/14:1/18:2) and FFA (4:0) were differentially expressed in LTNP and STNP.

Conclusion

In summary, the integration of lipid information can help us discover novel biomarkers to identify asymptomatic individuals and further deepen our understanding of the molecular pathogenesis of COVID-19.

Immunomodulation of cellular cytotoxicity to herpes simplex virus infection in pregnancy by inhibition of eicosanoid metabolism

In an effort to evaluate the relationships among pregnancy, cellular cytotoxicity and herpes simplex virus (HSV) infection, we conducted a series of experiments investigating: (1) the maternal cellular cytotoxic response to HSV infection as compared with non-pregnant hosts, (2) the influence of both cyclooxygenase and lipoxygenase products on cytotoxicity by selective inhibition of their metabolic pathways, and (3) the potential pregnancy-related differences in immune response to selective inhibition of eicosanoid metabolism. Indomethacin was used for cyclooxygenase blockade and nordihydroguaiaretic acid was used to evaluate lipoxygenase inhibition. In the non-infected animals no differences in cytotoxicity were observed between pregnant (1.5% +/- 0.7%) and non-pregnant (4.6% +/- 2.0%) groups. HSV infection increased cytotoxicity equally in both groups (pregnant: 10.6% +/- 2.0% vs. non-pregnant: 14.2% +/- 3.4%). Indomethacin did not significantly alter cytotoxicity in either the pregnant or the non-pregnant groups compared with controls (12.8% +/- 1.8% vs. 10.6% +/- 2.0% and 14.3% +/- 3.9% vs. 14.2% +/- 3.4%, respectively). In contrast, NDGA elicited a significant reduction in the cytotoxic response in both pregnant and non-pregnant hosts (6.2% +/- 1.1% vs. 10.6% +/- 2.0% and 5.7% +/- 1.1% vs. 14.2% +/- 3.4%, respectively). From our study we conclude that: (1) cytotoxicity is maintained at low levels in the absence of HSV infection, (2) HSV infection induces a significant augmentation in host cellular cytotoxicity, (3) pregnant and non-pregnant cytotoxic responses to HSV infection appear comparable, (4) indomethacin does not augment in vitro cytotoxicity to HSV infection and (5) NDGA suppresses cytotoxicity, providing evidence that lipoxygenase metabolites are essential to cytotoxic cell function.