Heme oxygenase-1 inducer hemin does not inhibit SARS-CoV-2 virus infection

Abstract

Antiviral agents with different mechanisms of action could induce synergistic effects against SARS-CoV-2 infection. Some reports suggest the therapeutic potential of the heme oxygenase-1 (HO-1) enzyme against virus infection. Given that hemin is a natural inducer of the HO-1 gene, the aim of this study was to develop an in vitro assay to analyze the antiviral potency of hemin against SARS-CoV-2 infection. A SARS-CoV-2 infectivity assay was conducted in Vero-E6 and Calu-3 epithelial cell lines. The antiviral effect of hemin, and chloroquine as a control, against SARS-CoV-2 virus infection was quantified by RT-qPCR using specific oligonucleotides for the N gene. Chloroquine induced a marked reduction of viral genome copies in kidney epithelial Vero-E6 cells but not in lung cancer Calu-3 cells. Hemin administration to the culture medium induced a high induction in the expression of the HO-1 gene that was stronger in Vero-E6 macaque-derived cells than in the human Calu-3 cell line. However, hemin treatment did not modify SARS-CoV-2 replication, as measured by viral genome quantification 48 h post-infection for Vero-E6 and 72 h post-infection for the Calu-3 lineages. In conclusion, although exposure to hemin induced strong HO-1 up-regulation, this effect was unable to inhibit or delay the progression of SARS-CoV-2 infection in two epithelial cell lines susceptible to infection.

Hemin as a novel candidate for treating COVID-19 via heme oxygenase-1 induction

“…The fact that viral protein expression was suppressed even when the cells had been treated with hemin after viral entry indicates that hemin may be able to suppress viral replication at the intracellular replication phase, similar to remdesivir 23 . However, a recent study suggested that HO-1 induced by hemin could not inhibit SARS-CoV-2 infection 24 . They demonstrated the unchanged viral RNA levels from the cell culture supernatants whereas we determined reduction of both viral RNA and viral protein in the cells after treatment with hemin.…”

Preclinical evaluation of a synthetic peptide vaccine against SARS-CoV-2 inducing multiepitopic and cross-reactive humoral neutralizing and cellular CD4 and CD8 responses

“…SARS-CoV-2 virus (isolate NAVARRA-2473) [ 32 ] used for these assays was obtained in April 2020 from the nasal sample of a COVID-19 patient hospitalized in Clínica Universidad de Navarra, after obtaining the patient´s informed consent and Regional Government permits. We first grew the virus in confluent Vero-E6 cells (ATCC® CRL-1586™) and supernatants were collected at 72 h post-inoculation, when a clear cytopathic effect was evident.…”

A Journey into the Clinical Relevance of Heme Oxygenase 1 for Human Inflammatory Disease and Viral Clearance: Why Does It Matter on the COVID-19 Scene?

“…However, the current literature regarding HO-1′s antiviral effect against SARS-CoV-2 remains unclear. Maestro et al showed that hemin does not inhibit SARS-CoV-2 viral replication in vitro [ 175 ]. Kidney epithelial Vero-E6 and lung Calu3 cell lines were treated with hemin and results showed that, despite a strong activation of HO-1 in both cell lines, there was no effect on SARS-CoV-2 viral replication, measured by the amplification of the N viral gene by RT-qPCR [ 175 ].…”

“…Maestro et al showed that hemin does not inhibit SARS-CoV-2 viral replication in vitro [ 175 ]. Kidney epithelial Vero-E6 and lung Calu3 cell lines were treated with hemin and results showed that, despite a strong activation of HO-1 in both cell lines, there was no effect on SARS-CoV-2 viral replication, measured by the amplification of the N viral gene by RT-qPCR [ 175 ]. However, a more recent report proposed hemin as a potential drug for treating COVID-19 via HO-1 induction [ 176 ].…”