Treatment with chondroitinase ABC alleviates bleomycin-induced pulmonary fibrosis

Area of Science:

• Pulmonary medicine
• Immunology
• Biochemistry

Background:

• Pulmonary fibrosis involves inflammatory cell accumulation and extracellular matrix deposition in the lungs.
• Macrophages are key mediators in the progression of lung inflammation to fibrosis.
• Mechanisms retaining macrophages in fibrotic lung tissue are not fully understood, though glycosaminoglycans modulate chemokine function.

Purpose of the Study:

• To investigate the role of chondroitin sulfate proteoglycans (CSPGs) in a mouse model of bleomycin-induced pulmonary fibrosis.
• To determine if CSPGs influence macrophage recruitment and retention in fibrotic lung tissue.
• To evaluate the therapeutic potential of chondroitinase ABC (ChABC) in treating pulmonary fibrosis.

Main Methods:

• Induction of pulmonary fibrosis in mice using intratracheal bleomycin.
• Administration of chondroitinase ABC (ChABC) or vehicle via intravenous injection and continuous infusion.
• Assessment of CSPG levels, macrophage accumulation, collagen deposition, and survival rates.

Main Results:

• CSPGs were significantly induced and augmented following bleomycin challenge.
• Deposited CSPGs retained macrophages in the fibrotic interstitium in a CD44-dependent manner, despite inhibiting early CCL2-dependent recruitment.
• ChABC treatment in vivo markedly improved mouse survival, reduced collagen deposition, and inhibited persistent macrophage accumulation.

Conclusions:

• CSPGs play a critical role in macrophage-mediated lung fibrogenesis.
• Targeting CSPGs with ChABC represents a potential therapeutic strategy for pulmonary fibrosis.
• ChABC treatment effectively reduces lung fibrosis by controlling macrophage persistence.