*Purpose: Post-transplant glomerular disease includes membranous glomerulopathy (MG), secondary or primary focal segmental glomerulosclerosis (FSGS). Furthermore, at post transplant, TG is an important cause of shortened graft survival due to disease recurrence. There are some studies exploring the gene expression changes in recurrent TG renal biopsies, but nothing has been done related to circulating small RNAs.

*Methods: For this purpose, we have performed Affymetrix microarray using renal biopsy samples from KT patients with normal (15) and recurrent TG (34) patients. Patient Characteristics were similar between groups.

*Results: There were 233 genes more than 2-fold differentially expressed between normal and TG patients. Of these 233 genes, majority of them (199) were upregulated. To investigate the possible role of circulating miRNAs in the gene expression in renal tissue, we performed upstream analysis using Ingenuity Pathway Analysis (IPA) and predicted miR21, miR-155 and miR-223 as regulators of these gene expression changes. We have validated the changes in miR-21, miR-155 and miR223 by RT-qPCR using TaqMan miRNA probes. As seen in Figure 1A, the genes in pink were up regulated in TG patients compared to normal and miR-155 downregulate these genes directly or indirectly. As expected, miR-155 was downregulated in TG compared normal serum samples based on RT-qPCR results (Figure 1B). This observation encouraged us to examine the global miRNA changes in serum of TG patients using next generation sequencing (NGS). Figure 1C shows the representative gel image showing the cloned library from circulating RNAs for NGS.

*Conclusions: Our initial results demonstrated correlation between the circulating miRNAs and gene expression in graft tissue. Further evaluation of these small RNAs will provide further critical information about TG recurrence post KT

Figure Legend: circulating miRNAs in TG patients. 1A. IPA analysis predicted that miR-155 is down-regulated in TG compared to normal transplant patients. 2A. Relative expression level of circulating miR-155 in TG and normal by RT-qPCR. 3A. Representative gel image showing the library preparation from circulating RNA in serum.

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