Alpha-tubulin enhanced renal tubular cell proliferation and tissue repair but reduced cell death and cell-crystal adhesion

Abstract

Adhesion of calcium oxalate (CaOx) crystals on renal tubular epithelial cells is a critical event for kidney stone disease that triggers many cascades of cellular response. Our previous expression proteomics study identified several altered proteins in MDCK renal tubular cells induced by CaOx crystals. However, functional significance of those changes had not been investigated. The present study thus aimed to define functional roles of such proteome data. Global protein network analysis using STRING software revealed α-tubulin, which was decreased, as one of central nodes of protein-protein interactions. Overexpression of α-tubulin (pcDNA6.2-TUBA1A) was then performed and its efficacy was confirmed. pcDNA6.2-TUBA1A could maintain levels of α-tubulin and its direct interacting partner, vimentin, after crystal exposure. Also, pcDNA6.2-TUBA1A successfully reduced cell death to almost the basal level and increased cell proliferation after crystal exposure. Additionally, tissue repair capacity was improved in pcDNA6.2-TUBA1A cells. Moreover, cell-crystal adhesion was reduced by pcDNA6.2-TUBA1A. Finally, levels of potential crystal receptors (HSP90, HSP70, and α-enolase) on apical membrane were dramatically reduced to basal levels by pcDNA6.2-TUBA1A. These findings implicate that α-tubulin has protective roles in kidney stone disease by preventing cell death and cell-crystal adhesion, but on the other hand, enhancing cell proliferation and tissue repair function.

More complete polarization of renal tubular epithelial cells by artificial urine

“…To study renal physiology and pathophysiology, cell lines are frequently grown on culture plates, Transwell, chemotaxis chamber, etc. Numerous studies have shown that these convenient and simple culture systems can be applied to study sophisticated mechanisms of kidney diseases 2 – 5 . In the case of Transwell culture system, its specialized feature for polarized cell cultivation that can separate upper and lower chambers allows independent access to both distinct fluid compartments and offers advantages for evaluation of cellular functions relating to apico-basolateral trans/paracellular transports 6 , 7 .…”

Cell cycle shift from G0/G1 to S and G2/M phases is responsible for increased adhesion of calcium oxalate crystals on repairing renal tubular cells at injured site

“…Scratch assay was performed according to the standard protocol 44,45 , with slight modifications. Briefly, MDCK cells were seeded in a six-well culture plate (Corning Inc., Corning, NY) at a density of 4 × 10 5 cells/well.…”

<p>Comparison of the adhesion of calcium oxalate monohydrate to HK-2 cells before and after repair using tea polysaccharides</p>

“…Kidney stones are a kind of global disease. Treatments exist, but the recurrence rate of kidney stones remains high, and no effective prevention methods have been found 1–3. The main components of calcium oxalate kidney stones are calcium oxalate monohydrate (COM) and calcium oxalate dihydrate.…”