Inhibition of HIF-2α Pathway as a Potential Therapeutic Strategy for Endothelial Dysfunction in Post-COVID Syndrome
Authors: Ribeiro Andrea , Kuchler Timon , Lech Maciej , Carbajo-Lozoya Javier , Adorjan Kristina , Stubbe Hans Christian , Seifert Martina , Wöhnle Anna , Kesseler Veronika , Negele Johanna , Heemann Uwe , Schmaderer Christoph 
Published: September 2024

Background

SARS-CoV-2 infection may lead to Post-COVID Syndrome (PCS), characterized by debilitating symptoms like persistent fatigue, cardiovascular symptoms, and cognitive dysfunction. Persistent endothelial dysfunction (ED) is a potential driver of ongoing symptoms. Yet, the underlying biological mechanisms remain unclear.

Methods

In this prospective observational study, we characterized 41 PCS patients and 24 healthy controls (HC, matched out of n = 204, recruited before the pandemic) and investigated the effect of SARS-CoV-2 Spike protein 1 (S1) and plasma from PCS patients on human retinal endothelial cells (HREC).

Results

Plasma samples from PCS patients exhibited significantly elevated erythropoietin, VEGF and MCP-1 alongside decreased IL-6 levels compared to HC. Low Haemoglobin and Haematocrit were negatively associated with PCS severity. VEGF levels were positively correlated with Anti-S1 IgG levels in patients and upregulated on mRNA level in HREC exposed to S1. Additionally, S1 exposure promoted ROS production and transiently activated HIF-1α in HREC. Persistent activation of HIF-2α by S1 led to disrupted endothelial integrity. HREC exposed to plasma from severely affected PCS patients showed increased ROS and compromised barrier function. Treatment with Belzutifan, a HIF-2α inhibitor, restored barrier integrity in HREC exposed to S1 or PCS-plasma.

Conclusion

These findings suggest that HIF-2α-mediated ED in PCS might be a potential therapeutical target for Belzutifan.

Trial registration

URL:https://www.clinicaltrials.gov; Unique identifier:NCT05635552

Novelty and significance

What Is Known?

Endothelial dysfunction (ED) is a consequence of acute SARS-CoV-2 infection and may lead to Post-COVID syndrome (PCS) symptoms.

Patients with PCS show elevated inflammation and endothelial dysfunction markers.

Spike proteins can persist for up to 12 months post-infection, driving ongoing inflammation and immune activation.

What New Information Does This Article Contribute?

Low haemoglobin (Hb) and high VEGF correlate with higher Anti-S1 IgG and low Hb is associated with higher C19-YRS severity score.

PCS patients exhibit higher Erythropoietin (EPO) levels when compared to HC.

Spike protein 1 (S1) alone and PCS patient’s plasma induce endothelial dysfunction primarily through HIF-2α activation.

Both S1 and PCS plasma cause oxidative stress and disrupting endothelial integrity.

Inhibition of HIF-2α effectively restores endothelial barrier integrity disrupted by S1 and PCS plasma.

Persistent circulation of spike proteins can sustain chronic inflammation and immune activation in patients with PCS. Here we show that plasma from PCS patients exhibits significantly elevated levels of VEGF which positively correlates with Anti-S1 IgG. Low haemoglobin was associated with higher Anti-S1 IgG titres and correlated with a higher C19-YRS severity score. Levels of EPO were higher in PCS patients, with a more pronounced effect observed in patients with cardiovascular symptoms. In human retinal endothelial cells, both S1 and plasma from PCS patients primarily induce ED through HIF-2α activation, rather than NF-κB. Both factors lead to significant oxidative stress, evidenced by increased ROS production which in turn disrupts endothelial barrier integrity and function. Notably, Belzutifan, a HIF-2α inhibitor, can restore this compromised endothelial function, offering a potential therapeutic target for PCS.

Graphical Abstract