Microbiology and Infectious Disease

Telomerase RNA component knockout exacerbates S. aureus pneumonia by extensive inflammation and dysfunction of T cells

Yasmina Reisser
Franziska Hornung
Antje Häder
Thurid Lauf
Sandor Nietzsche
Bettina Löffler
Stefanie Deinhardt-Emmer author has email address

Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
Else Kröner Graduate School for Medical Students “JSAM”, Jena University Hospital, 07747 Jena, Germany
Center for Electron Microscopy, Jena University Hospital, Ziegelmühlenweg 1, 07743 Jena, Germany

https://doi.org/10.7554/eLife.100433.1

Open access
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Figures and data

Terc^ko/ko mice exhibit more severe pneumonia with increased mortality and a higher bacterial load.
A) Clinical score of non-infected and infected young WT (n =10, 5 non-infected and 5 infected), old WT (n =10, 5 non-infected and 5 infected), and Terc^ko/ko (n =8, 3 non-infected and 5 infected) mice. The age and genetic background of the different groups is depicted below.
B) Bacterial load of the lungs of infected mice at 24 hpi. Data is displayed as logarithmic.
C) Relative body weight of young WT, old WT and Terc^ko/ko mice. Relative body weight displays body weight at 24 hpi as a percentage of the body weight at the time of infection.
D) Relative lung weight of young WT, old WT, and Terc^ko/ko mice. Relative lung weight displays lung weight at 24 hpi as a percentage of the current body weight.
E) Immunofluorescence staining of lung tissue of infected young (WT 8 weeks), old (WT 2 years), and Terc^ko/ko mice. Lungs were stained for S. aureus (green), actin (red), and DAPI (blue). Representative pictures are shown for each group.
*p < 0.05, **p < 0.01, ***p<0.001. P calculated by Kruskal-Wallis-test (A-D). Each replicate is displayed as a data point.

Lungs of Terc^ko/ko mice display excessive inflammation and NLRP3 inflammasome activation.
A) Pro-inflammatory cytokines measured in the lungs of non-infected and infected young WT (each n=3), old WT (each n=4) and Terc^ko/ko mice (non-infected: n=3, with systemic infection: n=2 and infected: n=1). Infected Terc^ko/ko mice were grouped into with systemic and without systemic infection. Data is displayed on a logarithmic scale.
B) Heatmap of overall gene expression in the different mice cohorts analyzed. Gene expression is displayed as the log2 of the fragments per kilobase of transcript per million fragments mapped (fpkm) of each individual gene. Red indicates upregulation, and green indicates downregulation of the gene expression. The respective mouse groups are visualized above the heatmap. For each mouse cohort three biological replicates were sequenced.
C) Heatmap of differentially expressed genes (DEG) belonging to the NLRP3 inflammasome pathway. Red indicates upregulation, and blue indicates downregulation of the gene. Differential gene expression analysis was conducted using the DESeq2 software as well as negative binomial distribution. For FDR calculation the Benjamini-Hochberg procedure was used. Heatmaps were constructed using R Studio. Only significant DEGs (p-value < 0.05) were displayed in the heatmap. Non-significant genes were set to zero and are shown as white. DEGs are displayed as log2fold-change. For each group three biological replicates were sequenced and used for analysis. For clarity, the heatmap has been split in half, and no column clustering has been performed. The respective groups used for the comparison are indicated below each column.
D) Overview of the most differentially enriched KEGG pathways between infected young and Terc^ko/ko mice. The dot plot was constructed using R Studio. ns ≥ 0.05, *p < 0.05, **p < 0.01, ***p<0.001, ****p < 0.0001. P calculated by Kruskal-Wallis-test (A). Each replicate is displayed as a data point.

Elevated expression of pro-inflammatory M1 macrophages markers and chemokines are present in the lungs of infected Terc^ko/ko mice.
A) Colorized SEM picture of an AM from young WT mice during phagocytosis of S. aureus. Heatmap of differentially expressed macrophage markers (B) and DEGs belonging to the chemokine signaling pathway (C). Red indicates upregulation, and blue indicates downregulation of the gene. Differential gene expression analysis was conducted using the DESeq2 software as well as negative binomial distribution. For FDR calculation the Benjamini-Hochberg procedure was used. Heatmaps were constructed using R Studio. Only significant DEGs (p-value < 0.05) were displayed in the heatmap. Non-significant genes were set to zero and are shown as white. DEGs are displayed as log2fold-change. For each group three biological replicates were sequenced and used for analysis. The respective groups used for the comparison are indicated below each column.

TCR in infected Terc^ko/ko mice is partially downregulated.
Heatmap of differentially expressed T helper cell markers (A) and DEGs belonging to the TCR signaling pathway (C). Red indicates upregulation, and blue indicates downregulation of the gene. Differential gene expression analysis was conducted using the DESeq2 software as well as negative binomial distribution. For FDR calculation the Benjamini-Hochberg procedure was used. Heatmaps were constructed using R Studio. Only significant DEGs (p-value < 0.05) were displayed in the heatmap. Non-significant genes were set to zero and are shown as white. DEGs are displayed as log2fold-change. For each mouse cohort three biological replicates were sequenced and used for analysis. The respective groups used for the comparison are indicated below each column. B) Percentage of CD3⁺-living cells in non-infected young WT (n=3), old WT (n=3), and Terc^ko/ko mice (n=5) spleen. Cells were analyzed with flow cytometry. Gene expression levels in fpkm of CD247 (D), PDCD1 (E), and CD4 (F) in young WT (n=3), old WT (n=3), and Terc^ko/ko mice (n=3). ns ≥ 0.05, *p < 0.05, **p < 0.01. P calculated by Kruskal-Wallis-test (B; D-F). Each replicate is displayed as a data point.

T cells of Terc^ko/ko mice do not adequately react to bacterial challenge.
(A) Schematic representation of experiment. Murine T cells and AMs were isolated, co-cultured, and stimulated with heat-killed S. aureus with an MOI5 for 24 hours.
(B) Colorized SEM picture of the experimental setup. An AM close to a T cell, is shown.
(C) Immunofluorescence staining of infected and non-infected AMs from young WT and Terc^ko/ko mice. AMs were stained with antibodies for S. aureus (red), actin (purple), and DAPI (blue).
(D) CD247 expression measured with flow cytometry of non-infected and infected T cells (left) and co-cultured T cells and AMs (right) of young WT (each n=3) and Terc^ko/ko mice (each n=3) after 24 hpi. CD247 expression is displayed as geometric mean fluorescence intensity (gMFI).
(E) Il-1α from supernatants of T cells (left) and co-cultured T cells and AMs (right) of young WT (each n=3) and Terc^ko/ko mice (each n=3) at 2 and 24 hpi. ns ≥ 0.05, *p < 0.05. P calculated by Kruskal-Wallis-test (D-E). Each replicate is displayed as a data point.

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