JCPyV miR-J1-5p in Urine of Natalizumab-Treated Multiple Sclerosis Patients

Abstract

The use of Natalizumab in Multiple Sclerosis (MS) can cause the reactivation of the polyomavirus JC (JCPyV); this may result in the development of progressive multifocal leukoencephalopathy (PML), a rare and usually lethal disease. JCPyV infection is highly prevalent in worldwide population, but the detection of anti-JCPyV antibodies is not sufficient to identify JCPyV infection, as PML can develop even in patients with negative JCPyV serology. Better comprehension of the JCPyV biology could allow a better understanding of JCPyV infection and reactivation, possibly reducing the risk of developing PML. Here, we investigated whether JCPyV miR-J1-5p-a miRNA that down-regulates the early phase viral protein T-antigen and promotes viral latency-could be detected and quantified by digital droplet PCR (ddPCR) in urine of 25 Natalizumab-treated MS patients. A 24-month study was designed: baseline, before the first dose of Natalizumab, and after 1 (T1), 12 (T12) and 24 months (T24) of therapy. miR-J1-5p was detected in urine of 7/25 MS patients (28%); detection was possible in three cases at T24, in two cases at T12, in one case at T1 and T12, and in the last case at baseline and T1. Two of these patients were seronegative for JCPyV Ab, and viral DNA was never found in either urine or blood. To note, only in one case miR-J1-5p was detected before initiation of Natalizumab. These results suggest that the measurement of miR-J1-5p in urine, could be a biomarker to monitor JCPyV infection and to better identify the possible risk of developing PML in Natalizumab-treated MS patients.

Keywords: JCPyV; biomarker; miRNA; multiple sclerosis; rehabilitation.

Figure 1

Genomic organization of the polyomavirus JC (JCPyV). ori: origin of replication region; NCCR: non-coding control region; LTAg: large T-Antigen; sTAg: small T-antigen; T’_{(135,136,165)}: T-antigen splice variants [15,16]; VP1-3: major capsid proteins; Agno: Agnoprotein (agno); pA: polyadenylation site; ORF: open reading frame [17,18].

Figure 2

miR-J1-5p and JCPyV DNA detection in urine samples of Natalizumab-treated Multiple Sclerosis patients. Black boxes: positivity for both miR-J1-5p and JCPyV DNA; dark grey boxes: miR-J1-5p positivity alone; light grey boxes: JCPyV DNA positivity alone; white boxes: absence of both nmiR-J1-5p and JCPyV DNA. miR-J1-5p copies/ng are indicated inside the boxes. In the right columns the presence of anti-JCPyV Antibodies (Ab) and JCPyV DNA for each patient is shown. For the exact timing of DNA viral detection in urine and blood, please see Table S1. Mo: Month; pts.n: patient number; N/D: not defined; MS: Multiple Sclerosis; POS: positive; NEG: negative.