Expression of the readthrough transcript CiDRE in alveolar macrophages boosts SARS-CoV-2 susceptibility and promotes COVID-19 severity

SARS-CoV2 infection in whole lung primarily targets macrophages that display subset-specific responses

Deciphering the initial steps of SARS-CoV-2 infection, that influence COVID-19 outcomes, is challenging because animal models do not always reproduce human biological processes and in vitro systems do not recapitulate the histoarchitecture and cellular composition of respiratory tissues. To address this, we developed an innovative ex vivo model of whole human lung infection with SARS-CoV-2, leveraging a lung transplantation technique. Through single-cell RNA-seq, we identified that alveolar and monocyte-derived macrophages (AMs and MoMacs) were initial targets of the virus. Exposure of isolated lung AMs, MoMacs, classical monocytes and non-classical monocytes (ncMos) to SARS-CoV-2 variants revealed that while all subsets responded, MoMacs produced higher levels of inflammatory cytokines than AMs, and ncMos contributed the least. A Wuhan lineage appeared to be more potent than a D614G virus, in a dose-dependent manner. Amidst the ambiguity in the literature regarding the initial SARS-CoV-2 cell target, our study reveals that AMs and MoMacs are dominant primary entry points for the virus, and suggests that their responses may conduct subsequent injury, depending on their abundance, the viral strain and dose. Interfering on virus interaction with lung macrophages should be considered in prophylactic strategies.

Impact of the COVID-19 Infection on Head and Neck Cancer Treatment During Hospitalization

Objective The after-effects of coronavirus disease 2019 (COVID-19) infection are still unknown; therefore, we investigate the possibility that COVID-19 may interrupt cancer treatment and impact prognosis. Methods We examined the characteristics, prognosis, and changes in treatment options before and after COVID-19 in 11 head and neck cancer patients who were infected with COVID-19 after admission for cancer treatment at Gifu University Hospital. These patients were compared to 110 patients unaffected by COVID-19 during the same period. To identify the effects of COVID-19 on the cancer treatment sequence, we examined the rates of overall survival, progression-free survival, and completion, as well as radiation dosage in radiotherapy and cisplatin dosage in chemoradiotherapy. Results All 11 patients with COVID-19 had their planned cancer treatment postponed or interrupted. There was no significant difference in overall or progression-free survival compared to patients without COVID-19. Notably, only 3/6 of the COVID-19-affected patients completed radiotherapy compared to 42/46 unaffected patients. The ratio of actual radiation dose to planned dose was significantly impaired in COVID-19 affected patients group (98.3% vs. 88.6%). Cisplatin dosage in chemoradiation was not significantly different in either the radical (100 mg/m2, every three weeks) or adjuvant (40 mg/m2, every one week) treatment groups. Conclusion COVID-19 infection in head and neck cancer patients had no apparent impact on cancer prognosis. However, when restricted to irradiation, the treatment completion rate and the ratio of planned to actual dose decreased significantly, underscoring the impact of COVID-19 infection on cancer treatment. The difference in irradiation may affect the success of patients' treatment going forward, and it should be explored whether irradiation can be continued without delay.

Combination therapy with oral antiviral and anti-inflammatory drugs improves the efficacy of delayed treatment in a COVID-19 hamster model

BACKGROUND

Pulmonary infection with SARS-CoV-2 stimulates host immune responses and can also result in the progression of dysregulated and critical inflammation. Throughout the pandemic, the management and treatment of COVID-19 has been continuously updated with a range of antiviral drugs and immunomodulators. Monotherapy with oral antivirals has proven to be effective in the treatment of COVID-19. However, treatment should be initiated in the early stages of infection to ensure beneficial therapeutic outcomes, and there is still room for further consideration on therapeutic strategies using antivirals.

METHODS

We studied the therapeutic effects of monotherapy with the oral antiviral ensitrelvir or the anti-inflammatory corticosteroid methylprednisolone and combination therapy with ensitrelvir and methylprednisolone in a delayed dosing model of hamsters infected with SARS-CoV-2.

FINDINGS

Combination therapy with ensitrelvir and methylprednisolone improved respiratory conditions and reduced the development of pneumonia in hamsters even when the treatment was started after 2 days post-infection. The combination therapy led to a differential histological and transcriptomic pattern in comparison to either of the monotherapies, with reduced lung damage and down-regulation of expression of genes involved in the inflammatory response. Furthermore, we found that the combination treatment is effective in case of infection with either the highly pathogenic delta or circulating omicron variants.

INTERPRETATION

Our results demonstrate the advantage of combination therapy with antiviral and corticosteroid drugs in COVID-19 treatment from the perspective of lung pathology and host inflammatory responses.

FUNDING

Funding bodies are described in the Acknowledgments section.