Use of proteomics to unravel novel markers of chronic renal allograft dysfunction

Hongmin Zhou¹, Ying Gao⁵, Ke Wu², Yi Xu³, Wentao He⁴, Weina Zhang⁵, Zemin Fang¹, Lanjun Cai⁵, Xinguang Lin⁵, Zhenlong Luo⁵, Hui Guo⁵, Zhonghua Klaus Chen⁵.

¹Department of Cardiac Thoracic Surgery, Tongji Hospital, Tongji Medical College, HUST; ²Department of General Surgery, Union Hospital, Tongji Medical College, HUST;
³Department of Decorative Surgery, Tongji Hospital, Tongji Medical College, HUST; ⁴Department of Endocrinology, Tongji Hospital, Tongji Medical College, HUST;
⁵Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, HUST Key Laboratory of Organ Transplantation, Ministry of Education; P.R. China.

Most late renal allograft failure was attributed to chronic allograft dysfunction (CGD), but its precise diagnosis, pathogenesis and treatment were largely unknown. The purpose of this study was to identify chronic renal allograft dysfunction biomarkers in human serum using two-dimensional differential in-gel electrophoresis (2-D DIGE) and RP-HPLC-ESI/MS. Serum samples were divided into four groups: chronic allograft dysfunction (CGD), long-term stable renal function (SRF), acute rejection (AR) and healthy volunteer (N). Serum samples were firstly processed using Multiple Affinity Removal Column to selectively remove albumin, IgG, IgA, transferrin, haptoglobin and antitrypsin. The samples were split into two sets. First set was used to discover the biomarker candidates while the second set of samples was used for validation. Differentially proteins were analyzed using 2-D DIGE. A total of 39 protein spots were found to be significantly increased or decreased in serum from CGD group compared to other three groups (Fig.1). These spots were excised, digested, and analyzed by RP-HPLC-ESI/MS. 22 differentially expressed proteins were identified in serum from CGD group. Galectin-7 and clusterin, two of these proteins were confirmed by ELISA analysis in the independent set of serum samples. Confirmed galectin-7 and clusterin may be serum biomarkers in CGD patients. Furthermore, these two proteins may provide great insights into understanding the pathogenesis and potential treatment strategy of CGD.