An international study published in the journal Nature Medicine offers clues as to why COVID-19 tends to affect older people, males and smokers more severely.
"There are molecular changes associated with these variables, likely responsible, at least in part, for some of the differences we see in susceptibility and severity of disease," said co-author Nicholas Banovich, an associate professor at TGen.
Those changes include a tendency to produce larger amounts of proteins that let coronavirus enter cells.
Based on 31 studies and more than 1.3 million cells, researchers found certain airway cells produce larger amounts of ACE2 (angiotensin-converting enzyme 2), the receptor that lets the coronavirus "dock" with a cell, and in some cases TMPRSS2 (transmembrane protease, serine 2), which allows it inside.
Banovich, who researches why lung diseases affects some people differently than others, contributed to the study as a member of the Lung Biological Network of the Human Cell Atlas, a working group of hundreds of scientists around the world who seek to describe every cell in the human body.
The study was unique in that it involved data on individual cells and cell types. Such research often relies on ground-up "bulk" tissue samples, which might consist of several kinds of cell and add "noise" to the signal.
"In response to these sort of environmental factors like smoking or age, that signal just kind of can get washed out by the expression of other genes coming from all of these other cells," said Banovich.
