A new collaborative study from researchers at the Perelman School of Medicine at the University of Pennsylvania and Duke University describes a unique process of lung tissue regeneration in response to injury—observing that certain groups of pulmonary cells have more plasticity than previously thought.

“It's as if the lung cells can regenerate from one another as needed to repair missing tissue, suggesting that there is much more flexibility in the system than we have previously appreciated,” explained Jon Epstein, M.D., chair of the department of cell and developmental biology at University of Pennsylvania School of Medicine and co-senior author on the current study. “These aren't classic stem cells that we see regenerating the lung. They are mature lung cells that awaken in response to injury. We want to learn how the lung regenerates so that we can stimulate the process in situations where it is insufficient, such as in patients with COPD [chronic obstructive pulmonary disease].”

The findings from this study were published today in Nature Communications through an article entitled “Plasticity of Hopx+ type 1 alveolar cells to regenerate type II cells in the lung.”

Anatomically within lung tissue, alveoli are the terminal branch of the pulmonary tree and composed of two primary cell types. The long, thin type 1 pneumocytes are responsible for exchanging oxygen and carbon dioxide, whereas type 2 pneumocytes secrete a phospholipid surfactant that helps keep airways open.

Dr. Epstein and his colleagues showed that in mice the two types of pneumocytes are derived from the same embryonic progenitor cells. Using a mouse model in which a section of the lung was removed, the researchers were able to show a single cell culture of type 1 pneumocytes added to the resected area could give rise to type 2 cells, and vice-versa.  

“We decided to test that hypothesis about type 1 cells,” said Rajan Jain, M.D., instructor in the department of medicine at Duke University and co-first author on the hubstudy. “We found that type 1 cells give rise to the type 2 cells over about three weeks in various models of regeneration. We saw new cells growing back into these new areas of the lung. It's as if the lung knows it has to grow back and can call into action some type 1 cells to help in that process.”

Interestingly, the investigators found that a cell type thought to be at its terminal differentiation point can revert to a another cell type under the right conditions—in this instance, inducing injury and repair response to the pulmonary tissue.

Additionally, the scientists are looking to apply the information they learned from the current study to tissues of the intestine and skin, in order to study the underlying mechanisms of stem cell maintenance and differentiation. Furthermore, they are optimistic that they will be able to apply their current findings to an array of pulmonary disorders where alveoli cells are typically damaged.    

“We want to know if we can, and how, to make new lung cells as work-arounds for diseased alveoli cells,” said Dr. Jain.

Previous articleCelgene Takes $45M Minority Stake in Mesoblast
Next articleCRUK Subsidiary, Medivir to Develop Cancer Drugs Targeting ADAM8