Natalizumab-induced POU2AF1/Spi-B upregulation

Abstract

Objectives:To assess messenger RNA (mRNA) expression of POU2AF1 and Spi-B and their potential regulatory microRNAs (miRNAs) in natalizumab-treated patients with multiple sclerosis and in therapy-associated progressive multifocal leukoencephalopathy (PML).Methods:Expression of POU2AF1/Spi-B was analyzed by using real-time reverse transcription PCR assays on isolated B/CD8+ T lymphocytes and peripheral blood mononuclear cells (PBMCs) from cohorts of untreated and natalizumab-treated patients with and without PML. Longitudinal expression analysis was performed on CD4+, CD8+ T and B cells from 14 patients who interrupted natalizumab therapy for 8 weeks. The miRNA profiling was conducted in PBMCs from 5 untreated and 5 natalizumab-treated patients using low-density arrays followed by validation with single miRNAs assays in untreated and natalizumab-treated patients.Results:POU2AF1 and Spi-B mRNAs were upregulated in B and CD8+ T cells from natalizumab-treated patients, which was validated in PBMCs from different cohorts of natalizumab-treated patients with and without PML, with a noteworthy higher expression of Spi-B in patients with PML. In contrast, downregulation of POU2AF1/Spi-B expression was measured in B and CD8+ T cells after natalizumab discontinuation. Seventeen differentially expressed miRNAs including miR-10b, a regulator of POU2AF1 mRNA, were identified in long-term natalizumab-treated patients compared with untreated ones.Conclusions:Upregulation of POU2AF1 and Spi-B, known transactivators of the JC virus, the causative agent for PML, and its association with occurrence of PML in natalizumab-treated patients, corroborates POU2AF1/Spi-B as potential biomarkers for PML risk, which merits further evaluation.

Do Human Endogenous Retroviruses Contribute to Multiple Sclerosis, and if So, How?

“…For example, miRNAs which are downregulated in T cells during active disease are upregulated by NAT during remission [ 132 ]. Conversely, a number of miRNAs such as mR-126 and miR-17 are downregulated during NAT therapy upon entry into remission but are upregulated in patients during relapse [ 133 , 134 ]. It is tempting to conclude that NAT therapy reduces the expression of HERV-W/MSRV in B cells and monocytes by changing the pattern of miRNA expression, and indeed, this may be part of the mechanism underpinning this phenomenon.…”

Current immunotherapies for multiple sclerosis and neuromyelitis optica spectrum disorders: the similarities and differences

“…Cases of PML due to the use of fingolimod or DMF are fortunately rare [177,178] . However, the overall risk of PML with natalizumab use is high (4 per 1000) [179][180][181] . Patients with MS taking natalizumab should be switched to another DMD with a lower PML risk, if the anti-JC virus antibody index exceeds 0.9 during treatment.…”

A link between long-term natalizumab dosing in MS and PML

“…In this issue of Neurology® Neuroimmunology & Neuroinflammation , Meira et al 5 may have put another important piece of this puzzle in place with the observation that natalizumab temporally regulates gene expression in immune system cells that can be targets for JCV infection prior to entry into the brain, notably B cells. Their investigation showed that the same family of transcription factors, POU2AF1, which includes the DNA binding protein SpiB, were upregulated in natalizumab-treated patients with MS over months.…”

“…It is perhaps in these compartments that the archetype variant transforms into the virulent PML regulatory region using cellular mechanism of nucleotide rearrangement or perhaps combining with other viral DNAs like Epstein-Barr virus that are also present in such tissues like marrow. 8 Then natalizumab comes into play, forcing migration of CD34+ and pre-B cells into the circulation, another unique biological effect of natalizumab by blocking homing of these cells in the marrow, where SpiB, upregulated by miRNA 126 or other factors attributed to natalizumab with long-term dosing, 5 gives JCV a boost for replication if present in these cells. JCV can be found in the peripheral circulation as free virions or in cell compartments that may enter the brain, finding highly susceptible glial cells and initiating a lytic infection.…”