Gene Expression Analysis and Urinary Biomarker Assays Reveal Activation of Tubulointerstitial Injury Pathways in a Rodent Model of Chronic Proteinuria (Doxorubicin Nephropathy)

Abstract

Background: Tubular atrophy and interstitial fibrosis are well-recognized sequelae of chronic proteinuria; however, little is known regarding the molecular pathways activated within tubulointerstitium in chronic proteinuric nephropathies. Methods: To investigate the molecular mechanisms of proteinuria-associated tubulointerstitial (TI) disease, doxorubicin nephropathy was induced in rats. Progression of disease was monitored with weekly urinary biomarker assays. Because histopathology revealed multifocal TI injury, immunodirected laser capture microdissection was used to identify and isolate injured proximal tubules, as indicated by kidney injury molecule-1 immunolabeling. Adjacent interstitial cells were harvested separately. Gene expression microarray, manual annotation of gene lists, and Gene Set Enrichment Analysis were performed. A subset of the regulated transcripts was validated by quantitative PCR and immunohistochemistry. Results: Severe proteinuria preceded tubular injury biomarkers by 1 week. Histology revealed multifocal, mild TI damage at 3 weeks, which progressed in severity at 5 weeks. Affymetrix microarray analysis revealed tissue-specific regulation of gene expression. Manual annotation of gene lists, gene set enrichment analysis, and urinary biomarker assays revealed similarities to pathways activated in direct TI injuries. This suggests commonalities amongst the molecular mechanisms of TI injury secondary to proteinuria, ischemia-reperfusion, and nephrotoxicity.

Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain

“…Podocyte dysfunction and consequent proteinuria has been recently reinforced as a major determinant of tubular injury, inflammation and apoptosis leading to progressive IFTA [44]. According to our present study and previous literature [45] IFTA developed as part of DXR nephropathy. Urinary NGAL excretion is a sensitive marker of tubular damage not only during acute kidney injury [[46, 47],] but also during IFTA [48].…”

Toxicity and Safety Evaluation of Doxorubicin-Loaded Cockleshell-Derived Calcium Carbonate Nanoparticle in Dogs

“…However, the carrier molecules are entrapped within the slit diaphragm due to the size of the carrier molecules used in drug delivery leading to renal tubular tissue injury [ 82 ]. The glomerular and tubular damage observed in our study was similar to the lesion seen in rodent as reported by Cianciolo et al [ 83 ] and Manno et al [ 5 ] in rodent and mini pig animal models, respectively. In addition, our results also agree with the works of Anan et al [ 84 ] as clusters of nuclear material were observed as a result of free radical production from lipid peroxidation.…”

“…The kidney is also a targeted organ for DOX as previously reported by Salouege et al [ 92 ] and Cianciolo et al [ 83 ], but the order of the DOX organ affinity is less when compared to the heart due to cardiolipin concentration. Zhou et al [ 93 ] demonstrated that the apical region of proximal tubules which have microvillus and abundant podocytes was responsible for the secretion of nephrin and podocin, which are structural components of slit diaphragm.…”

The interplay between genetic background and sexual dimorphism of doxorubicin-induced cardiotoxicity

“…In addition to the well-recognized DOX-induced cardiotoxicity, DOX causes significant nephrotoxicity characterized by chronic proteinuria, glomerular sclerosis, and interstitial and tubular involvement primarily in rodent models [ 48 – 50 ]. Similar to DOX-induced cardiotoxicity, oxidative stress is thought to play the major role in mediating DOX-induced nephrotoxicity [ 51 ].…”