Protein Network Analysis and Functional Studies of Calcium Oxalate Crystal‐Induced Cytotoxicity in Renal Tubular Epithelial Cells

Abstract

Our previous expression study has reported a set of proteins with altered levels in renal tubular cells after exposure to calcium oxalate monohydrate (COM) crystals, which are the main composition of kidney stones. However, their functional significance remained largely unknown. In this study, protein network analysis revealed that the significantly altered proteins induced by COM crystals were involved mainly in three main functional networks, including i) cell proliferation and wound healing; ii) oxidative stress and mitochondrial function; and iii) cellular junction complex and integrity. Cell proliferation and wound healing assays showed that the COM-treated cells had defective proliferation and tissue healing capability, respectively. Oxyblot analysis demonstrated accumulation of the oxidized proteins, whereas intracellular ATP level was significantly increased in the COM-treated cells. Additionally, level of zonula occludens-1 (ZO-1), a tight junction protein, was significantly decreased, consistent with the significant declines in transepithelial resistance (TER) and level of RhoA signaling molecule in the COM-treated cells. These findings indicate significant perturbations in mitochondrial and oxidative stress axis that cause defective cell proliferation, tissue healing capability, junctional protein complex, and cellular integrity of renal tubular epithelial cells exposed to COM crystals that may play important roles in kidney stone pathogenesis.

Protective Cellular Mechanism of Estrogen Against Kidney Stone Formation: A Proteomics Approach and Functional Validation

“…On the other hand, the decreased level of intracellular ATP is associated with reduced risk of oxidative stress and cell/tissue injury . It was thus plausible that the decreased intracellular ATP level observed in our present study was one of the protective mechanisms of estrogen to prevent renal cells/tissue from CaOx‐induced oxidative stress and renal injury frequently observed in kidney stone disease …”

“…[49,50] It was thus plausible that the decreased intracellular ATP level observed in our present study was one of the protective mechanisms of estrogen to prevent renal cells/tissue from CaOx-induced oxidative stress and renal injury frequently observed in kidney stone disease. [51,52]…”

Ceftriaxone Calcium Crystals Induce Acute Kidney Injury by NLRP3-Mediated Inflammation and Oxidative Stress Injury

“…In addition to the indirect mechanisms involving inflammation and oxidative stress injury that we have discussed, ceftriaxone calcium crystals could also harm tubular cells by directly inducing tubular cell death. Crystals are known to be cytotoxic when they come in direct contact with the tubular epithelium [ 28 ]. For example, Thongboonkerd et al have demonstrated that CaOx monohydrate crystals (COM) tightly adhere to MDCK cells with subsequent detrimental effects on the cells [ 29 ].…”

Roles for Exosome in Various Kidney Diseases and Disorders

“…Between the two common hydrated forms of CaOx crystals, CaOx monohydrate (COM) is more prominent and more pathogenic than CaOx dihydrate (COD) in kidney stone disease (Semangoen et al, 2008a;Semangoen et al, 2008b;Thongboonkerd et al, 2008;Peerapen et al, 2018). By differences in adhesive capability, atomic lattice, binding kinetics and surface atomic pattern of these two hydrated forms, COM crystal adheres more tightly to renal epithelial cell surface and is then internalized into the cells and subsequently transferred to the renal interstitium (Chiangjong and Thongboonkerd, 2012;Kanlaya et al, 2013;Chaiyarit et al, 2016;Chiangjong and Thongboonkerd, 2016;.…”