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2024
Journal Article
Title
Identification of CRTH2 as a New PPARĪ³-Target Gene in T Cells Suggested CRTH2 Dependent Conversion of Th2 Cells as Therapeutic Concept in COVID-19 Infection
Abstract
Background: COVID-19 is a serious viral infection, which is often associated with a lethal outcome. Therefore, understanding mechanisms, which affect the immune response during SARS-CoV2 infection, are important.
Methods: To address this, we determined the number of T cells in peripheral blood derived from intensive care COVID-19 patients. Based on our previous studies, evaluating PPARĪ³-dependent T cell apoptosis in sepsis patients, we monitored PPARĪ³ expression. We performed a next generation sequencing approach to identify putative PPARĪ³-target genes in Jurkat T cells and used a PPARĪ³ transactivation assay in HEK293T cells. Finally, we translated these data to primary T cells derived from healthy donors.
Results: A significantly reduced count of total CD3+ T lymphocytes and the CD4+ and CD8+ subpopulations was observed. Also, the numbers of anti-inflammatory, resolutive Th 2 cells and FoxP3-positive regulatory T cells (Treg) were decreased. We observed an augmented PPARĪ³ expression in CD4+ T cells of intensive care COVID-19 patients. Adapted from a next generation sequencing approach in Jurkat T cells, we found the chemoattractant receptorāhomologous molecule expressed on T helper type 2 cells (CRTH2) as one gene regulated by PPARĪ³ in T cells. This Th 2 marker is a receptor for prostaglandin D and its metabolic degradation product 15-deoxy-ā12,14-prostaglandin J2 (15d-PGJ2), an established endogenous PPARĪ³ agonist. In line, we observed an increased PPARĪ³ transactivation in response to 15d-PGJ2 treatment in HEK293T cells overexpressing CRTH2. Translating these data to primary T cells, we found that Th 2 differentiation was associated with an increased expression of CRTH2. Interestingly, these CRTH2+ T cells were prone to apoptosis.
Conclusion: These mechanistic data suggest an involvement of PPARĪ³ in Th 2 differentiation and T cell depletion in COVID-19 patients.
Methods: To address this, we determined the number of T cells in peripheral blood derived from intensive care COVID-19 patients. Based on our previous studies, evaluating PPARĪ³-dependent T cell apoptosis in sepsis patients, we monitored PPARĪ³ expression. We performed a next generation sequencing approach to identify putative PPARĪ³-target genes in Jurkat T cells and used a PPARĪ³ transactivation assay in HEK293T cells. Finally, we translated these data to primary T cells derived from healthy donors.
Results: A significantly reduced count of total CD3+ T lymphocytes and the CD4+ and CD8+ subpopulations was observed. Also, the numbers of anti-inflammatory, resolutive Th 2 cells and FoxP3-positive regulatory T cells (Treg) were decreased. We observed an augmented PPARĪ³ expression in CD4+ T cells of intensive care COVID-19 patients. Adapted from a next generation sequencing approach in Jurkat T cells, we found the chemoattractant receptorāhomologous molecule expressed on T helper type 2 cells (CRTH2) as one gene regulated by PPARĪ³ in T cells. This Th 2 marker is a receptor for prostaglandin D and its metabolic degradation product 15-deoxy-ā12,14-prostaglandin J2 (15d-PGJ2), an established endogenous PPARĪ³ agonist. In line, we observed an increased PPARĪ³ transactivation in response to 15d-PGJ2 treatment in HEK293T cells overexpressing CRTH2. Translating these data to primary T cells, we found that Th 2 differentiation was associated with an increased expression of CRTH2. Interestingly, these CRTH2+ T cells were prone to apoptosis.
Conclusion: These mechanistic data suggest an involvement of PPARĪ³ in Th 2 differentiation and T cell depletion in COVID-19 patients.
Author(s)