CSPG4 and chronic obstructive pulmonary disease: The most and only significantly upregulated gene in COPD-derived LMSCs was CSGALNACT1, a gene encoding the enzyme that initiates chondroitin sulfate (CS) biosynthesis The only downregulated gene in COPD-derived LMSCs was CSPG4P13, chondroitin sulfate proteoglycan 4 pseudogene 13, a non-functional gene.