TNF and rheumatoid arthritis: Furthermore, overexpression of sTNFR2 or TNFR2 in human or rat BM-MSCs enhanced their therapeutic effects in mice and rats with RA (131, 132) and rats with cardiac ischemia (134, 147), which was associated with reduced TNF level and attenuated expression of IL1β and IL6. Macrophages are a major cell type that secretes TNF.