CLCN7 and rheumatoid arthritis: At the final differentiation time point (d14), cathepsin K, CLCN7 (chloride channel 7), and TCIRG (subunit of a V-type proton ATPase), three markers of osteoclast activity, were not affected in RA osteoclasts (n = 3) by palmitic acid or linoleic acid at mRNA level.