Mechanism and prevention of acute kidney injury from cast nephropathy in a rodent model
Wei-Zhong Ying, Christopher E. Allen, Lisa M. Curtis, Kristal J. Aaron, Paul W. Sanders
Wei-Zhong Ying, Christopher E. Allen, Lisa M. Curtis, Kristal J. Aaron, Paul W. Sanders
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Research Article

Mechanism and prevention of acute kidney injury from cast nephropathy in a rodent model

Abstract

A common renal complication of multiple myeloma is “myeloma kidney,” a condition also known as cast nephropathy. The renal lesions (casts) are directly related to the production of monoclonal immunoglobulin free light chains (FLCs), which coprecipitate with Tamm-Horsfall glycoprotein (THP) in the lumen of the distal nephron, obstructing tubular fluid flow. Here, we report that analysis of the binding interaction between FLCs and THP demonstrates that the secondary structure and key amino acid residues on the complementarity-determining region 3 (CDR3) of FLCs are critically important determinants of the molecular interaction with THP. The findings permitted development of a cyclized competitor peptide that demonstrated strong inhibitory capability in the binding of FLCs to THP in vitro. When used in a rodent model of cast nephropathy, this cyclized peptide construct served as an effective inhibitor of intraluminal cast formation and prevented the functional manifestations of acute kidney injury in vivo. These experiments provide proof of concept that intraluminal cast formation is integrally involved in the pathogenesis of acute kidney injury from cast nephropathy. Further, the data support a clinically relevant approach to the management of renal failure in the setting of multiple myeloma.

Authors

Wei-Zhong Ying, Christopher E. Allen, Lisa M. Curtis, Kristal J. Aaron, Paul W. Sanders

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Figure 5

Overlay (far-Western) assays demonstrating the interaction between FLCs and THP.

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Overlay (far-Western) assays demonstrating the interaction between FLCs ...
(A) Coomassie-stained gel (left) depicts the monomeric and dimeric forms of a monoclonal FLC and the VL domain, which had been enzymatically cleaved from the FLCs. The adjacent blot (right) demonstrates that human THP bound to monomers, dimers, and polymeric FLCs, as well as the VL domain of the FLCs. (B) Results of an experiment that used cyclic peptide 1 (AHX-CLSADSSGSYLYVCKK) to compete with the biotinylated VL domain of FLC ITPBLL86 for binding to THP immobilized onto PVDF membrane. The reversible protein stain demonstrated the presence of THP in each lane (top). Addition of increasing molar amounts, relative to THP, of the cyclic peptide prevented binding of the VL domain to THP. (C) Results of an overlay assay that used cyclized peptide 1 (AHX-CLSADSSGSYLYVCKK) or a cyclized control peptide (AHX-CLSAHSSGSYLYVCKK) to compete with biotinylated THP for binding to κ2 FLC immobilized onto PVDF membrane. The reversible protein stain demonstrated the presence of κ2 FLC in each lane (top). Cyclized peptide 1, but not the cyclized control peptide, dose dependently inhibited binding of THP to the κ2 FLC (bottom).