Insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinases-2: differential expression and secretion in human kidney tubule cells

Abstract

We have characterized the expression and secretion of the acute kidney injury (AKI) biomarkers insulin-like growth factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in human kidney epithelial cells in primary cell culture and tissue. We established cell culture model systems of primary kidney cells of proximal and distal tubule origin and observed that both proteins are indeed expressed and secreted in both tubule cell types in vitro. However, TIMP-2 is both expressed and secreted preferentially by cells of distal tubule origin, while IGFBP7 is equally expressed across tubule cell types yet preferentially secreted by cells of proximal tubule origin. In human kidney tissue, strong staining of IGFBP7 was seen in the luminal brush-border region of a subset of proximal tubule cells, and TIMP-2 stained intracellularly in distal tubules. Additionally, while some tubular colocalization of both biomarkers was identified with the injury markers kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, both biomarkers could also be seen alone, suggesting the possibility for differential mechanistic and/or temporal profiles of regulation of these early AKI biomarkers from known markers of injury. Last, an in vitro model of ischemia-reperfusion demonstrated enhancement of secretion of both markers early after reperfusion. This work provides a rationale for further investigation of these markers for their potential role in the pathogenesis of acute kidney injury.

High-Throughput Sequencing to Detect Novel Likely Gene-Disrupting Variants in Pathogenesis of Sporadic Brain Arteriovenous Malformations

“…mesoderm, by which originate vasculature, connective tissue, skeleton, and urinary tract. All considered variants affect genes associated to connective tissue, glomerulus, and skeleton impairment (Demirdas et al, 2017;Emlet et al, 2017;Schock et al, 2017;Wunnenburger et al, 2017). However, a critical point regards the clinical significance of variants detected by the analysis.…”

PEBP1 Wardens Ferroptosis by Enabling Lipoxygenase Generation of Lipid Death Signals

“…Proximal tubule cells were procured, isolated, and characterized from cortices of whole adult human kidneys obtained from the Center for Organ Recovery and Education (CORE, Pittsburgh, PA, USA) through a University of Pittsburgh approved protocol as previously described (Emlet et al, 2017). Renal cortices from four male donors with a median age of 54 years (IQR of 44-64) were subjected to enzymatic and mechanical dissociation by razor blade mincing and digestion with 200 u/ml Collagenase IV, and 100 u/ml DNAse in HBSS for 1 h at 37 °C, followed by sieving with a 250 μm sieve (Gilson, Lewis Center, OH, USA) to remove undigested material.…”

Genetic variants disrupt human RGS14 binding to NHERF1 and regulation of NPT2A-mediated phosphate transport

“…Kidney Expression of RGS14-The RGS14 gene is located on chromosome 5, adjacent to SLC34A1, which encodes the NPT2A protein, a renal phosphate transporter. Therefore, we examined the expression of RGS14 in human kidney samples and in proximal and distal tubule cells isolated from these samples (33). As shown in Fig To extend these findings, we sought to determine and characterize the action of RGS14 on PTH-sensitive phosphate transport in RPTEC, a non-transformed line of human proximal tubule cells (34).…”

“…Tissue and Cell Preparation-Human adult kidney (HAK10, 65yo M; HAK55, 63yo/M; HAK57, 53yo/M; HAK58, 63yo/F); CD13 (proximal tubule), and CD227 (distal tubule) cells were from male and female donors, as indicated. Tissue procurement and processing have been described (33). CD13 and CD227 cells were seeded on 6 well plates.…”