Mild SARS-CoV-2 infection modifies DNA methylation of peripheral blood mononuclear cells from COVID-19 convalescents

Background: Coronaviruses such as SARS-CoV-2 may circumvent host defence mechanisms by hijacking host proteins, possibly by altering DNA methylation patterns in host cells. While most epigenetic studies have been performed in severely ill COVID-19 patients, studies on individuals who have recovered from mild-to-moderate disease remain scarce. The aim of this study was to assess epigenome-wide DNA methylation patterns in COVID-19 convalescents compared to uninfected controls from before and after the pandemic outbreak began. Methods: DNA was extracted from peripheral blood mononuclear cells originating from uninfected controls before (Pre20, n=5) and after (Con, n=18) 2020, COVID-19 convalescents (CC19, n=14) and symptom-free individuals with a SARS-CoV-2-specific T cell response (SFT, n=6), as well as from Pre20 (n=4) samples stimulated in vitro with SARS-CoV-2. Subsequently, epigenome-wide DNA methylation analyses were performed using the Illumina MethylationEPIC 850K array, and statistical and bioinformatic analyses comprised differential DNA methylation, pathway over-representation and module identification network analyses. Results: DNA methylation patterns of COVID-19 convalescents were altered as compared to uninfected controls, with similar results observed in in vitro stimulations of PBMC with SARS-CoV-2. Differentially methylated genes from the in vivo comparison constituted the foundation for the identification of a possibly SARS-CoV-2-induced module, containing 66 genes of which six could also be identified in corresponding analyses of the in vitro data (TP53, INS, HSPA4, SP1, ESR1 and FAS). Pathway over-representation analyses revealed involvement of Wnt, cadherin and apoptosis signalling pathways amongst others. Furthermore, numerous interactions were found between the obtained differentially methylated genes from both settings and the network analyses when overlaying the data unto the SARS-CoV-2 interactome. Conclusions: Epigenome-wide DNA methylation patterns of individuals that have recovered from mild-to-moderate COVID-19 are different from those of non-infected controls. The observed alterations during both in vivo and in vitro exposure to SARS-CoV-2 showed involvement in interactions and pathways that are highly relevant to COVID-19. The present study provides indications that DNA methylation is one of several epigenetic mechanisms that is altered upon SARS-CoV-2 infection. Further studies on the mechanistic underpinnings should determine whether the observed effects are reflecting host-protective antiviral defence or targeted viral hijacking to evade host defence.

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IN VITRO REPLICATION OF EPIZOOTIC HEMORRHAGIC DISEASE AND BLUETONGUE VIRUSES IN WHITE-TAILED DEER PERIPHERAL BLOOD MONONUCLEAR CELLS AND VIRUS-CELL ASSOCIATION DURING IN VIVO INFECTIONS

Journal of Wildlife Diseases ◽

10.7589/0090-3558-33.3.574 ◽

1997 ◽

Vol 33 (3) ◽

pp. 574-583 ◽

Cited By ~ 9

Author(s):

David E. Stallknecht ◽

Elizabeth W. Howerth ◽

M. Lisa Kellogg ◽

Charlotte F. Quist ◽

Tracy Pisell

Keyword(s):

Peripheral Blood Mononuclear Cells ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Hemorrhagic Disease ◽

Peripheral Blood Mononuclear ◽

In Vitro Replication ◽

Cell Association ◽

Blood Mononuclear Cells

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Simvastatin Suppresses Interleukin Iβ Release in Human Peripheral Blood Mononuclear Cells Stimulated With Cholesterol Crystals

Journal of Cardiovascular Pharmacology and Therapeutics ◽

10.1177/1074248418776261 ◽

2018 ◽

Vol 23 (6) ◽

pp. 509-517 ◽

Cited By ~ 10

Author(s):

Anna J. Boland ◽

Nisha Gangadharan ◽

Pierce Kavanagh ◽

Linda Hemeryck ◽

Jennifer Kieran ◽

...

Keyword(s):

Cardiovascular Disease ◽

Peripheral Blood Mononuclear Cells ◽

Nlrp3 Inflammasome ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Human Peripheral Blood ◽

Peripheral Blood Mononuclear ◽

Blood Mononuclear Cells

Statins are mainstream therapy in the treatment and prevention of cardiovascular disease through inhibitory effects on cholesterol synthesis. However, statins’ beneficial effects in cardiovascular disease may also be attributable to their role as anti-inflammatory mediators. Here, we investigated the effects of simvastatin treatment on expression levels of interleukin (IL) 1β in both patient with hyperlipidemia and healthy human peripheral blood mononuclear cells (PBMCs) using cholesterol crystals (CC), a cardiovascular pathogenic stimulus for activation of the NOD-like receptor pyrin domain–containing protein 3 (NLRP3) inflammasome. Cholesterol crystal-induced NLRP3 inflammasome activation was used to trigger maturation and release of IL-1β in PBMCs. Specifically, isolated PBMCs from patients with hyperlipidemia at baseline and following 8 weeks of in vivo treatment with simvastatin (10-20 mg) daily were stimulated with lipopolysaccharide (LPS; 100 ng/mL) for 3 hours to induce proIL-Iβ expression followed by CC (2 mg/mL) stimulation for further 18 hours to activate the NLRP3 inflammasome complex to induce maturation/activation of IL-1β. Peripheral blood mononuclear cells were also isolated from healthy donors and stimulated in vitro with simvastatin (50, 25, 5, and 2 µmol/L) prior to stimulation with LPS and CC as described above. The effects of simvastatin treatment on levels of IL-1β expression were determined by enzyme-linked immunosorbent assay and western blot. Both in vitro and in vivo treatments with simvastatin led to a significant reduction in the levels of expression of IL-1β in response to stimulation with CC. Simvastatin inhibits the expression and activation of IL-1β induced by CC in PBMCs, which may contribute to its protective role in patients with cardiovascular disease.

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Neopterin suppresses the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase in human peripheral blood mononuclear cells

Pteridines ◽

10.1515/pterid-2013-0037 ◽

2013 ◽

Vol 24 (3) ◽

pp. 237-243

Author(s):

Sebastian Schroecksnadel ◽

Elena-Sophia Ledjeff ◽

Johanna Gostner ◽

Christiana Winkler ◽

Katharina Kurz ◽

...

Keyword(s):

Peripheral Blood Mononuclear Cells ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Human Peripheral Blood ◽

Peripheral Blood Mononuclear ◽

Indoleamine 2,3 Dioxygenase ◽

Blood Mononuclear Cells ◽

Ifn Γ

AbstractIn vitro, large amounts of neopterin are released from human monocyte-derived macrophages and dendritic cells primarily upon stimulation with Th1-type cytokine interferon-γ (IFN-γ). IFN-γ also induces the enzyme indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan (TRP) to form kynurenine (KYN). IDO-mediated TRP catabolism is very effective in suppressing the proliferation of T lymphocytes as well as of pathogens in vitro and in vivo. In this study, we investigated whether exogenously added neopterin may influence IDO activity in resting and in stimulated peripheral blood mononuclear cells (PBMC). PBMC were isolated from healthy donors, and neopterin was added in a concentration range from 0.01 to 50 μmol/L. After 30 min, PBMC were stimulated or not with 10 μg/mL of mitogen phytohemagglutinin (PHA). After 48 h, culture supernatants were collected, KYN and TRP concentrations were measured by high-performance liquid chromatography, and the ratio of KYN vs. TRP was calculated as an estimate of IDO activity. Spontaneous as well as PHA-induced TRP breakdown was suppressed by exogenously added neopterin in a dose-dependent way; the lowest active concentration of neopterin was <100 nmol/L. As neopterin concentrations in the nanomolar range are commonly observed in patients suffering from infections, sepsis, or uremia, our results suggest that neopterin formation might also serve as a feedback mechanism to slow down TRP degradation in vivo.

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