Blocking two proteins reduced lung scarring in animals — a new lead for a disease with almost no good treatments
Lung fibrosis replaces healthy tissue with scar tissue, makes breathing progressively harder, and has almost no treatments that reverse the damage.
Scientists studying age-related changes in the lung identified two proteins — ID1 and ID3 — that show abnormally elevated activity in certain lung cells during fibrosis. These proteins belong to the ID family (Inhibitors of Differentiation), a class of transcription factors that regulate which genes are switched on or off inside a cell. Under normal conditions they play roles in cell growth and specialisation, but in fibrotic lung tissue they appear to contribute to the runaway activity of fibroblasts — the cells responsible for producing scar tissue.
By reducing the expression of ID1 and ID3 using targeted molecular techniques, the researchers achieved measurable reductions in fibrosis in animal models. That result should be read carefully. Dozens of compounds have suppressed fibrosis in animals and failed in clinical trials. But the finding adds a new mechanistic layer to the understanding of how pulmonary fibrosis develops and sustains itself.
Why age is the dominant risk factor
Pulmonary fibrosis is overwhelmingly a disease of older adults. It is rare before the age of fifty and its incidence rises steeply with age, which makes it a core concern in longevity medicine. One prominent theory holds that cellular senescence — a state in which cells stop dividing, refuse to die, and secrete inflammatory signals that damage surrounding tissue — is a key driver of the fibrotic reaction. Earlier work in animal models showed that clearing senescent cells can partially reverse fibrosis. The ID1/ID3 pathway explored in this new study does not map directly onto the senescence story, but it suggests there may be multiple molecular routes feeding into the same destructive process. Effective treatment might require addressing several of them simultaneously.
The research was reported via Fight Aging!, a platform tracking developments in ageing biology. The underlying experiments were conducted in animals, which means the translation to human therapy is far from guaranteed. Inhibiting ID proteins could also carry off-target effects in other tissues where these molecules serve functional roles, including the immune system and stem cell compartments.
The irreversibility problem
What makes pulmonary fibrosis so difficult to treat is a self-reinforcing loop: once scar tissue forms, it alters the mechanical properties of the lung in ways that amplify further fibrotic signalling. The two drugs currently approved for idiopathic pulmonary fibrosis — pirfenidone and nintedanib — slow progression but do not reverse existing damage. That irreversibility is precisely what makes the disease so feared as a late-life condition, and why researchers keep searching for mechanisms upstream of the damage itself.
Whether targeting ID1 and ID3 will ever translate into a viable therapy remains deeply uncertain. What the study does provide is a mechanistic foothold — a new set of molecular targets worth investigating in more complex experimental systems and, eventually, in humans.