2023-06-26 11:00:00
The very precise identity card of the 61 distinct cell types that make up the human lung (healthy or sick): this is what a team of doctors and scientists from the Côte d’Azur was able to establish.
A major work, published in the very prestigious journal Nature Medicine, and which is part of the “Human Organ Atlas” program launched in 2020. Financially supported by Mark Zuckerberg, the boss of Meta (Facebook, etc.), this pharaonic project named HCA (“Human Cell Atlas”) aims to produce a catalog of all the cells that make up the human body. Organ by organ.
a first atlas
Mission accomplished concerning the respiratory tract, thanks to the “Lung Network” of the HCA consortium, in which Prs Sylvie Leroy and Charles-Hugo Marquette, from the Nice University Hospital, and Drs Laure-Emmanuelle Zaragosi and Pascal Barbry have participated since the first hour, from the CNRS in Sophia Antipolis.
“This first atlas was established using single-cell sequencing technologies and from samples from 486 individuals. The majority of them had a respiratory pathology such as asthma, chronic obstructive pulmonary disease (COPD), fibrosis, pulmonary hypertension or cystic fibrosis. 107 were “healthy” volunteers [ne décrivant aucun symptôme d’une maladie respiratoire au moment du prélèvement, Ndlr]“, detail the scientists, who “recruited” these “healthy” volunteers within their own teams. The challenge is to understand what keeps a lung in good health and what makes it “tip” into pathology.
Characteristic footprints
If research still needs to be conducted to decipher these mechanisms, this work has already provided a first, fairly general lesson: the diversity of the cells that make up the body is much greater than expected. “When this project was launched, it was almost established that the human being is composed of at most a few hundred distinct cell types! This number is in fact much higher, as the first results show.”
Regarding the lung specifically, scientists make the following observations: “Healthy subjects are very similar” in terms of cellular composition, regardless of age, sex or ethnicity. On the other hand, there are significant differences between a healthy lung and a diseased lung. With, for each pathology, cellular specificities.”
Researchers cite the example of asthma, which “leaves very characteristic imprints”. And very early.
For the anecdote, the team evokes the case of a colleague, a healthy volunteer to participate in the study, and in whom the signatures of asthma were highlighted, while he showed no symptoms. “Two years later, he actually expressed asthma.” “This work also shows how certain cells in the respiratory tract, even if they are scarce, play an important role in diseases such as cystic fibrosis or lung cancer”adds Professor Sylvie Leroy.
Modify the effectiveness of treatments
With this new mapping of the lung, doctors and researchers around the world (all data is freely available) will now be able to approach respiratory diseases in a new way, knowing what keeps them healthy.
“We will be able to better understand the functioning of each cell and its interactions with its neighbours; this is an essential step in the development of new screening and diagnostic tools, but also in the personalization of treatments and in modeling their effectiveness. ex vivo [en dehors de l’organisme, sans geste invasif, Ndlr].”
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