“…We have also given some examples of indirect protective effect of RA on collagen by influencing the factors regulating its biosynthesis, e.g., extracellular signal-regulated protein kinases 1 and 2 [ 36 ]. In the current study we also proved the beneficial effect of 100 µM RA which prevented changes induced by BP-3 in the expression of other important proteins such as chaperones (PDI, HSP47) enzymes (GLT25D1, MMP-1, MMP-2), sulfated GAGs and decorin, involved in the modification, folding, structure stabilization, secretion, fibrillogenesis, and remodelling of collagen [ 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. Normalizing or significantly reducing these adverse changes in the presence of RA has prevented BP-3-induced cellular stress, which either activates UPR and partially restores cell homeostasis but may also lead to cell apoptosis [ 47 , 48 , 51 ].…”