SPON2 and chronic kidney disease: It has been reported that salidroside ameliorates renal interstitial fibrosis by inhibiting the TLR4/NF-κB and MAPK signaling pathways, mindin deficiency alleviates renal fibrosis through inhibiting NF-κB and TGF-β/Smad pathways [40], kallistatin protects renal fibrosis via modulation of Wnt/β-catenin signaling [41], and Zhen-wu-tang ameliorates adenine-induced chronic renal failure in rats by regulating of the canonical Wnt4/beta-catenin signaling in the kidney [42].