A group from Brown University, etc. has reported that Chitinase 3-like-1 (CHI3L1/YKL-40) could be a good therapeutic target for the new coronavirus (COVID-19).
https://pubmed.ncbi.nlm.nih.gov/33442679/
In the case of COVID-19, majority is asymptomatic or mild, but 10-20% of patients require hospitalization. Especially, it is so interesting that the severity of COVID-19 is deeply related to aging and comorbid disorders (such as diabetes, hypertension, obesity and metabolic syndrome, cardiovascular disease and chronic lung diseases like COPD and asthma). It is know that CHI3L1 is secreted from a spectrum of cells in response to a variety of injury and inflammation, and regulates innate and adaptive immunity and also protects apoptosis. What’s even more interesting is that CHI3L1 increases with aging and also with risk factors of COVID-19 (i.e., presence of comorbid disorders). Taking these things into consideration, authors focused on the relationship between CHI3L1 and angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), cathepsin L (CTSL).
In an in vivo experiment using mice, it was found that CHI3L1 stimulates expression of pulmonary ACE2, TMPRSS2, and CTSL. In other experiments using Calu-3 lung epithelial cells, the expression of ACE2, TMPRSS2, CTSL increased monotonically with CHI3L1 dose, and also it was found that a monoclonal antibody for CHI3L1 (FRG) strongly inhibits the expression of ACE2, TMPRSS2, and CTSL. In actual COVID-19 patients hospitalized, it was also indicated that there is a significant correlation between severity and CHI3L1.
These evidences suggest strongly that CHI3L1 could be a good therapeutic target for COVID-19. Let’s anticipate the future research.
