Figure: Potential mechanisms associated with cannabinoid mediated suppression of SARS-CoV-2 induced lung inflammation and fibrosis. ROS- Reactive oxygen species, IL- Interleukin; IFN- Interferon; MIP- Macrophage inhibitory protein; MCP- Monocyte chemotactic protein; ER-Endoplasmic reticulum.
Coronavirus disease-2019 (COVID-19), caused by Severe Acute Respiratory Syndrome coronoavirus-2 (SARS-CoV2) has emerged as a global pandemic, which was first reported in Wuhan, China. Recent reports have suggested that acute infection is associated with a cytokine superstorm, which contributes to the symptoms of fever, cough, muscle pain and in severe cases bilateral interstitial pneumonia characterized by ground glass opacity and focal chest infiltrates that can be visualized on computerized tomography scans (Rothan and Byrareddy, 2020). Currently, there are no effective antiviral drugs or vaccines against SARS-CoV2. In the recent issue of BBI, Zhang et al. (Zhang et al., 2020) thoroughly summarized the current status of potential therapeutic strategies for COVID-19. One of them, anti-IL6 receptor (Tocilizumab) antibody, resulted in clearance of lung consolidation and recovery in 90% of the 21 treated patients (Fu et al., 2020). Although promising, it has also produced adverse effects like pancreatitis and hypertriglyceridemia (Morrison et al., 2020), which make it imperative to explore effective alternative anti-inflammatory strategies. Here, we intend to highlight the potential effects of cannabinoids, in particular, the non-psychotropic cannabidiol (CBD), that has shown beneficial anti-inflammatory effects in pre-clinical models of various chronic inflammatory diseases and is FDA approved for seizure reduction in children with intractable epilepsy (Nichols and Kaplan, 2020).Like Δ9-tetrahydrocannabinol (Δ9-THC), the most well-studied cannabinoid, CBD decreased lung inflammation in a murine model of acute lung injury potentially through the inhibition of proinflammatory cytokine production by immune cells and suppressing exuberant immune responses (Ribeiro et al., 2015). CBD can inhibit the production of proinflammatory cytokines like interleukin (IL)-2, IL-6, IL-1α and β, interferon gamma, inducible protein-10, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and tumor necrosis factor-α (Nichols and Kaplan, 2020) (Fig. 1 ) that have been associated with SARS-CoV2 induced multi-organ pathology and mortality. In a murine model of chronic asthma, CBD reduced proinflammatory cytokine production, airway inflammation and fibrosis (Vuolo et al., 2019).