bioRxiv Science⌕ Search

bioRxiv · 10.1101/2020.07.18.200964

Respiratory Syncytial Virus Infections Induce Hypermetabolism in Pediatric Upper Airways

Abstract

To determine whether respiratory syncytial virus (RSV) regulates human metabolism, we used positron emission tomography (PET) of patient lungs along with bioenergetics and metabolomics of patient upper airway cells and fluids. We previously found a significant negative monotonic relationship between glucose uptake and respiratory viral infection in 20 pediatric patients (e.g., 70% of infected patients had glucose uptake within 0-3 days). In our recent study, 3 out of 4 patients positive for glucose uptake at later times (>5 days) were positive for RSV infection. At present, the bioenergetics of upper respiratory cells (URCs) from nasal pharyngeal aspirates have not been investigated, and in vitro studies indicate RSV reduces metabolism in cell lines. To define metabolic changes in RSV-infected pediatric patients, we acquired fresh aspirates from 6 pediatric patients. Immediately following aspiration of URCs, we measured the two major energy pathways using an XFe flux analyzer. Glycolysis and mitochondrial respiration were significantly increased in URCs from RSV-infected patients, and mitochondrial respiration was operating at near maximal levels, resulting in loss of cellular capacity to increase respiration with impaired coupling efficiency. Metabolomics analysis of metabolites flushed from the upper airways confirmed a significant increase in TCA cycle intermediates. Taken together, these studies demonstrate RSV induces significant hypermetabolism in pediatric patients lungs and respiratory tract. Thus, hypermetabolism is a potential anti-viral drug target and reveals RSV can regulate human metabolism. Contributions to the fieldMetabolic changes in humans in response to viral infection are largely unknown. In this brief clinical report, we find metabolism is markedly increased in live upper respiratory cells from infants infected with respiratory syncytial virus (RSV) concomitant to changes in metabolites in their upper airway fluids. This sheds light on viral induced hypermetabolism in the airways and offers potential biomarkers for RSV. In addition, this identifies potential therapeutic targets for host directed therapies of aberrant metabolism in RSV. This work has clinical impact as biomarkers and therapeutics for RSV are needed for this pervasive virus that causes infections with long term consequence for some children. Further, advancements in molecular mechanisms underpinning RSV infection biology are constrained by the difficulties in translating model systems to humans as well as relating human studies in adults to infants (Mestas and Hughes, 2004; Papin et al., 2013).

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Rezinciuc, S., Bezavada, L., Bahadoran, A., Ingels, J. F., Kim, Y.-Y., Cormier, S. A., Shulkin, B. L., Smallwood, H. S.. 2020-07-18. Respiratory Syncytial Virus Infections Induce Hypermetabolism in Pediatric Upper Airways. https://doi.org/10.1101/2020.07.18.200964

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

A single-cell transcriptomic atlas of the pigtail macaque lung

Background: The lungs undergo substantial physiological and immunological changes during respiratory illness to meet the host's increased metabolic and oxygen demands. These responses require coordination among epithelial, endothelial, stromal, and immune cells throughout the respiratory zone, interstitium, and vasculature. Nonhuman primates (NHPs) are a valuable model for studying pulmonary biology as they have similar anatomic, physiologic, and immunologic correspondence to humans. Despite the widespread use of NHPs in pulmonary research, the cellular diversity and molecular characteristics of the pigtail macaque lung remain incompletely defined. Methods: Parenchymal lung tissue from five adult female pigtail macaques (Macaca nemestrina) was dissociated into single cells and profiled using 10x Genomics 3' single-cell RNA sequencing (scRNA-Seq). Next, ambient RNA was removed and quality control analyses performed. Samples were then integrated using scVI and scANVI. Cell types were labeled after unsupervised clustering and subclustering, followed by manual annotation using canonical marker genes. We compared lineages and cell types with the Level 4 Human Lung Cell Atlas (HLCA) using scArches reference mapping and with the Rhesus Immune Reference Atlas (RIRA) using Seurat label transfer. Results: The atlas includes 61,323 cells representing 37 cell types in epithelial, mesenchymal, endothelial, lymphoid, and myeloid populations. Annotated populations included both major and rare lung cell types, including alveolar type I and II cells, club and multiciliated cells, aerocyte capillary, and lymphatic endothelial cells, pre-terminal bronchiole secretory cells, CD4+ and CD8+ T cells, and several innate-like lymphocyte populations (gamma delta T cells, MAIT-like cells, innate-like CD8+ T cells, and group 3 innate lymphoid cells). There was strong concordance at HLCA annotation level 4, including AT1 and AT2 cells (96% and 93%), B cells (94 to 97%), CD4+ T cells (99 to 100%), classical and non-classical monocytes (84% and 85%), alveolar macrophages (80%), and mast cells (96%). Immune populations mapped to the RIRA with similar fidelity (alveolar macrophages and B cells, 99%). Conclusions: While studies of pandemic respiratory infections, vaccines, and therapeutics rely on NHP disease models, this atlas provides a unique reference for epithelial, endothelial, stromal, and immune cell states in the pigtail macaque lung. We found that single-cell populations from the pigtail macaque lung are highly similar to those in the human lung at the lineage level. This reference will enable studies of pathogenesis and vaccine and drug efficacy in a highly translational model of the human lung.

systems biology↗

Cell cycling throttles epithelial--mesenchymal transition

Cell cycle phase is an understudied source of variation in gene expression. EMT is a case in point: this cell state transition that drives metastasis has been studied widely across tissue, stimulus, and microenvironmental conditions, yet cell cycle effects are routinely regressed out of single-cell EMT analyses. Here, we compare EMT between G1 and cycling (S/G2/M) cell states in two independent scRNA-seq datasets of TGF-{beta}-stimulated MCF10A mammary epithelial cells (varying dose and timepoint). G1 cells consistently show higher expression of EMT genes and upregulated RNA velocities than cycling cells, with the strongest upregulation in G1 EMT intermediate states. Consistent with the go-or-grow hypothesis, EMT and cell cycle programs inversely correlate; moreover, this anticorrelation extends to RNA velocity and strengthens with TGF-{beta} dose. We identify a 77-gene G1-specific EMT signature enriched for actin cytoskeletal and extracellular matrix genes that would otherwise be lost by regressing out cell cycle effects. This gene set prompts the hypothesis that, unconstrained by the cytoskeletal demands of mitosis, G1 cells have greater capacity to execute EMT. Further, we developed an EMT gene regulatory model coupled with a cell cycle module, and found through simulation that the model recapitulated this inverse EMT--cell cycle relationship. Using this model, we predict that cycle-selective chemotherapy enriches for the G1 intermediate state, which has high metastatic potential. Cell cycle phase thus ought not be regressed out of EMT states, given its influence on EMT.

systems biology↗

Multi-Enzyme Data-Independent Acquisition Mass Spectrometry for Proteoform-Aware Single-shot Proteomics

Biological regulation does not operate at the level of the protein but across ensembles of protein variants shaped by alternative splicing, post-translational modification and endogenous proteolytic processing. Yet most conventional bottom-up discovery proteomics workflows remain optimized for a canonical protein census, leaving much of the sequence-level variation invisible. Multi-enzyme digestion has been recognized as an effective strategy to expand sequence coverage and proteoform sensitivity, but existing implementations rely on resource-heavy per-enzyme liquid chromatography coupled to mass spectrometry (LC-MS) analysis, dedicated measurements for spectral library construction, and semi-manual reconciliation across multiple software tools, restricting the use to specialized laboratories and limited sample cohorts. Here we introduce mE-DIA, a multi-enzyme, proteoform-resolved data independent acquisition (DIA)-MS workflow that multiplexes complementary protease digested samples into a single DIA injection and processes them through a library-free pipeline within a single analysis engine, without supplemental data dependent acquisition (DDA)-MS measurements. The mE-DIA Pipeline graphical user interface orchestrates the analysis, and a dedicated proteoform inference algorithm and the interactive mE-DIA Peptide Mapper viewer make the sequence-level evidence explorable. Comparing the workflow to prevailing DDA-library-based multi-enzyme DIA on the same raw data and within shared search space showed increased identified protein groups by 30 % and protein groups quantified at [≤] 20 % CV by 47 %. A three-enzyme multiplex of the human pathogen Streptococcus pyogenes resolved 990 protein-backbone variants among 309 canonical protein entries, 1.8-fold more than the most productive single-enzyme analysis, including an H69 C-terminal proteoform of the ribosomal protein uS19 that the trypsin-only workflow did not resolve. By consolidating multi-enzyme acquisition, analysis and proteoform interpretation into one accessible toolset, mE-DIA brings sub-gene-resolved evidence within reach of routine single-shot discovery DIA proteomics.

systems biology↗