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Among the complications of diabetes, diabetic kidney disease (DKD) frequently emerges, typified by the detrimental effects on renal function, manifesting through inflammation, dysregulated lipid metabolism, and harm to podocytes. Existing research underscores the significance of the soluble form of C-X-C chemokine ligand 16 (CXCL16) within the context of renal impairments. However, whether CXCL16 is involved in the pathogenesis of DKD remains elusive. We report that CXCL16 levels in the serum and kidneys of individuals with DKD were elevated and correlated with various lipid parameters. The expression of CXCL16 in human podocytes subjected to high glucose or palmitic acid induction and exogenous CXCL16 administration in these cells were examined. Higher CXCL16 levels were linked to abnormal lipid metabolism. Exogenous CXCL16 administration induced lipid droplets, microfilament disorganization, apoptosis, oxidative stress, and inflammation, inhibited PPAR γ, up-regulated COX2 expression, and inhibited Nrf2 translocation in podocytes. Molecular analysis revealed that Curcumin (Cur), a polyphenolic compound derived from Curcuma longa and an Nrf2 agonist, targets the ATP-binding pocket of CXCL16, inhibiting its kinase activity. Meanwhile, Cur therapy alleviated podocyte injury, lipid accumulation, improved glomerulopathy, and reduced albuminuria. Furthermore, after silencing CXCL16 expression in podocytes using siRNA, the effects of exogenous CXCL16 were nullified, and Cur no longer exhibited any significant impact. Thus, CXCL16 participates in the pathogenesis of DKD. Inhibition of CXCL16 has shown promising results in experimental models, suggesting its beneficial effects in ameliorating DKD., Competing Interests: Declarations. Conflict of interest: All authors declare that they have no conflicts of interest., (© 2024. The Pharmaceutical Society of Korea.)

In the present study, we investigate the effect of curcumin, a major active component isolated from rhizomes of Curcuma longa, on the cytotoxicity of three human carcinoma cell lines (AGS, HT-29 and MGC803) in gastrointestinal tract and a normal gastric epithelial cell line GES-1, and the mechanism of curcumin-induced apoptosis. The results indicated that curcumin inhibited the gastrointestinal carcinoma cell growth in a dose-dependent manner and cytotoxicity was more towards the gastric carcinoma cell AGS and colon carcinoma cell HT-29 compared to normal gastric cell GES-1, and increased externalization of phosphatidylserine residue was observed by Annexin V/PI staining in the two cell lines. Treatment of AGS and HT-29 cells with curcumin enhanced the cleavage of procaspase-3, -7, -8 and -9. Meanwhile, curcumin induced endoplasmic reticulum (ER) stress and mitochondrial dysfunction as evidenced by up-regulation of CCAAT/enhancer binding protein homologous protein (CHOP), phosphorylation of JNK and down-regulation of SERCA2ATPase, release of cytochrome c, decrease of Bcl-2 and reduction of mitochondrial membrane potential in both AGS and HT-29 cells. Overexpression of bax, total JNK, phospho-FADD and total FADD were also observed in curcumin-treated HT-29 cells. Moreover, curcumin decreased cytosolic and ER Ca(2+), but increased mitochondrial Ca(2+) in the two cell lines. 2-Aminoethoxydiphenyl borate, an antagonist of inositol 1, 4, 5-triphosphate receptor, partly blocked curcumin-induced cytosolic Ca(2+) decrease in AGS and HT-29 cells. Additionally, carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of mitochondrial Ca(2+) uptake, reversed curcumin-triggered AGS and HT-29 cells growth inhibition. siRNA to CHOP markedly reduced curcumin-induced apoptosis. These results suggest that curcumin can impact on ER stress and mitochondria functional pathways in AGS and HT-29 cells, death receptor pathway was also involved in curcumin-treated HT-29 cells, thus identifying specific well-defined molecular mechanisms that may be targeted by therapeutic strategies.