Kevin J. Zwezdaryk

Ebola virus disease (EVD) survivors often present with clinical sequelae after acute disease resolution, called post-Ebola syndrome (PES). Why some survivors develop these sequelae and others do not is poorly defined. Altered metabolism has been noted in acute EVD but not studied in PES. We identified differential expression of metabolites involved in multiple metabolic pathways in EVD survivors with PES. This included the tricarboxylic acid cycle, amino acid, nucleotide, and short chain fatty acid metabolism. Several of these pathways are associated with immune dysfunction. The identified metabolites have potential use as biomarkers of post-Ebola syndrome.

Males suffer more severe outcomes during acute COVID-19 and a greater proportion of females develop post-acute sequalae of COVID-19 (PASC). To identify mechanisms of PASC, mice were infected with SARS-CoV-2 and viral, inflammatory, and behavioral outcomes were evaluated through 84 days post-infection. Sex differences were not observed in virus replication or persistence of viral RNA in pulmonary or extrapulmonary tissues. After infectious virus clearance, females exhibited persistent deficits in spatial working and recognition memory, and greater frequencies of inflammatory myeloid cells, neuroinflammation, and dysregulated T cells, including Tregs. Sex differences in persistent inflammation and cognitive impairments during PASC were mediated by the presence of two X chromosomes and infection-induced upregulation of the X-linked genes Xist and Tlr7, which was reversed by pharmacological inhibition of TLR7 activity during the PASC phase. Sustained X-linked TLR7-mediated inflammation underlies how the burden of PASC is greater for females and provides a therapeutic target.

Bioenergetic and biosynthetic processes are key indicators regulating adipose-derived stromal/stem cell (ADSC) function, health, and differentiation. A common method used to metabolically profile cells is the Seahorse XF Analyzer. This live-cell assay can be used to define key metabolic pathways, including glycolysis and oxidative phosphorylation. Here, we share optimized protocols to characterize metabolism of ADSCs under basal conditions and provide insight into further assays defining metabolic changes and/or dependency during ADSC differentiation. Key words ADSC Metabolism OXPHOS Glycolysis Mitochondria Differentiation Seahorse Analyzer ETC

Nephron endowment at birth impacts long-term renal and cardiovascular health, and it is contingent on the nephron progenitor cell (NPC) pool. Glycolysis modulation is essential for determining NPC fate, but the underlying mechanism is unclear. Combining RNA sequencing and quantitative proteomics we identify 267 genes commonly targeted by Wnt activation or glycolysis inhibition in NPCs. Several of the impacted pathways converge at Acetyl-CoA, a co-product of glucose metabolism. Notably, glycolysis inhibition downregulates key genes of the Mevalonate/cholesterol pathway and stimulates NPC differentiation. Sodium acetate supplementation rescues glycolysis inhibition effects and favors NPC maintenance without hindering nephrogenesis. Six2Cre-mediated removal of ATP-citrate lyase (Acly), an enzyme that converts citrate to acetyl-CoA, leads to NPC pool depletion, glomeruli count reduction, and increases Wnt4 expression at birth. Sodium acetate supplementation counters the effects of Acly deletion on cap-mesenchyme. Our findings show a pivotal role of acetyl-CoA metabolism in kidney development and uncover new avenues for manipulating nephrogenesis and preventing adult kidney disease.

Cytomegalovirus (CMV) is a master manipulator of host metabolic pathways. The impact of CMV metabolic rewiring during congenital CMV on immune function is unknown. CMV infection can directly alter glycolytic and oxidative phosphorylation pathways in infected cells. Recent data suggests CMV may alter metabolism in uninfected neighboring cells. In this mini review, we discuss how CMV infection may impact immune function through metabolic pathways. We discuss how immune cells differ between maternal and decidual compartments and how altered immunometabolism may contribute to congenital infections.

Antigen conformationshapes CD4+ T-cell specificity through mechanismsof antigen processing, and the consequences for immunity may rivalthose from conformational effects on antibody specificity. CD4+ Tcells initiate and control immunity to pathogens and cancer and areat least partly responsible for immunopathology associated with infection,autoimmunity, and allergy. The primary trigger for CD4+ T-cell maturationis the presentation of an epitope peptide in the MHC class II antigen-presentingprotein (MHCII), most commonly on an activated dendritic cell, andthen the T-cell responses are recalled by subsequent presentationsof the epitope peptide by the same or other antigen-presenting cells.Peptide presentation depends on the proteolytic fragmentation of theantigen in an endosomal/lysosomal compartment and concomitant loadingof the fragments into the MHCII, a multistep mechanism called antigenprocessing and presentation. Although the role of peptide affinityfor MHCII has been well studied, the role of proteolytic fragmentationhas received less attention. In this Perspective, we will brieflysummarize evidence that antigen resistance to unfolding and proteolyticfragmentation shapes the specificity of the CD4+ T-cell response toselected viral envelope proteins, identify several remarkable examplesin which the immunodominant CD4+ epitopes most likely depend on theinteraction of processing machinery with antigen conformation, andoutline how knowledge of antigen conformation can inform future effortsto design vaccines.

Pneumocystis jirovecii is the most common cause of fungal pneumonia in children under the age of 2 years. However, the inability to culture and propagate this organism has hampered the acquisition of a fungal genome as well as the development of recombinant antigens to conduct seroprevalence studies. In this study, we performed proteomics on Pneumocystis-infected mice and used the recent P. murina and P. jirovecii genomes to prioritize antigens for recombinant protein expression. We focused on a fungal glucanase due to its conservation among fungal species. We found evidence of maternal IgG to this antigen, followed by a nadir in pediatric samples between 1 and 3 months of age, followed by an increase in prevalence over time consistent with the known epidemiology of Pneumocystis exposure. Moreover, there was a strong concordance of anti-glucanase responses and IgG against another Pneumocystis antigen, PNEG_01454. Taken together, these antigens may be useful tools for Pneumocystis seroprevalence and seroconversion studies.

Human cytomegalovirus (HCMV) exploits host mitochondrial function to promote viral replication. HCMV gene products have been described to directly interact and alter functional or structural aspects of host mitochondria. Current antivirals against HCMV, such as ganciclovir and letermovir, are designed against viral targets. Concerns with the current antivirals include toxicity and viral resistance. Targeting host mitochondrial function is a promising alternative or complimentary antiviral approach as (1) drugs targeting host mitochondrial function interact with host targets, minimizing viral resistance, and (2) host mitochondrial metabolism plays key roles in HCMV replication. This review describes how HCMV alters mitochondrial function and highlights pharmacological targets that can be exploited for novel antiviral development.