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The observed alteration in BCL2 expression following lithium treatment is influenced by the choice of normalization method.

ABSTRACT: Upregulation of B-cell CLL/lymphoma (BCL)2 expression following lithium treatment is seemingly well established and has been related to the neuroprotective property of the drug. However, while demonstrated by some (but not all) studies based on low-throughput techniques (e.g. qPCR) this effect is not reflected in high-throughput studies, such as microarrays and RNAseq. This manuscript presents a systematic review of currently available reports of lithium's effect on BCL2 expression. To our surprise, we found that the majority of the literature does not support the effect of lithium on BCL2 transcript or protein levels. Moreover, among the positive reports, several used therapeutically irrelevant lithium doses while others lack statistical power. We also noticed that numerous low-throughput studies normalized the signal using genes/proteins affected by lithium, imposing possible bias. Using wet bench experiments and reanalysis of publicly available microarray data, here we show that the reference gene chosen for normalization critically impacts the outcome of qPCR analyses of lithium's effect on BCL2 expression. Our findings suggest that experimental results might be severely affected by the choice of normalizing genes, and emphasize the need to re-evaluate stability of these genes in the context of the specific experimental conditions.

SUBMITTER: Odeya D

PROVIDER: S-EPMC5913222 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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The observed alteration in BCL2 expression following lithium treatment is influenced by the choice of normalization method.

Odeya Damri D Galila Agam A Lilah Toker T

Scientific reports 20180423 1

Upregulation of B-cell CLL/lymphoma (BCL)2 expression following lithium treatment is seemingly well established and has been related to the neuroprotective property of the drug. However, while demonstrated by some (but not all) studies based on low-throughput techniques (e.g. qPCR) this effect is not reflected in high-throughput studies, such as microarrays and RNAseq. This manuscript presents a systematic review of currently available reports of lithium's effect on BCL2 expression. To our surpr ...[more]

PMID: 29686228

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Project description:BackgroundLithium is considered by many as the gold standard medication in the management of bipolar disorder (BD). However, the clinical response to lithium is heterogeneous, and the molecular basis for this difference in response is unknown. In the present study, we sought to determine how the peripheral blood gene expression profiles of patients with bipolar disorder (BD) changed over time following intitiation of treatment with lithium, and whether differences in those profiles over time were related to the clinical response.MethodsIllumina Sentrix Beadchip (Human-6v2) microarrays containing?>?48,000 transcript probes were used to measure levels of expression of gene-expression in peripheral blood from 20 depressed subjects with BD prior to and every two weeks during 8?weeks of open-label treatment with lithium.Changes in gene-expression were compared between treatment responders (defined as a decrease in the Hamilton Depression Rating Scale of 50% or more) and non-responders. Pathway analysis was conducted using GeneGO Metacore software.Results127 genes showed a differential response in responders vs. non-responders. Pathway analysis showed that regulation of apoptosis was the most significantly affected pathway among these genes. Closer examination of the time-course of changes among BCL2 related genes showed that in lithium-responders, one month after starting treatment with lithium, several anti-apoptotic genes including Bcl2 and insulin receptor substrate 2 (IRS2) were up-regulated, while pro-apoptotic genes, including BCL2-antagonist/killer 1 (BAK1) and BCL2-associated agonist of cell death (BAD), were down-regulated. In contrast, in lithium non-responders, BCL2 and IRS2 were down-regulated, while BAK1 and BAD up-regulated at the one-month time-point.ConclusionsThese results suggest that differential changes in the balance of pro- and anti- apoptotic gene-expression following treatment with lithium may explain some of the heterogeneity in clinical response in BD patients.

Project description:ObjectiveAxial spondyloarthritis (axial SpA) is characterized by inflammation of the spine and sacroiliac joints and can also affect extraarticular sites, with the most common manifestation being uveitis. Here we report the incidence of uveitis flares in axial SpA patients from the RAPID-axSpA trial, including ankylosing spondylitis (AS) and nonradiographic (nr) axial SpA.MethodsThe RAPID-axSpA (NCT01087762) trial is double-blind and placebo-controlled to week 24, dose-blind to week 48, and open-label to week 204. Patients were randomized to certolizumab pegol (CZP) or placebo. Placebo patients entering the dose-blind phase were re-randomized to CZP. Uveitis events were recorded on extraarticular manifestation or adverse event forms. Events were analyzed in patients with/without history of uveitis, and rates reported per 100 patient-years.ResultsAt baseline, 38 of 218 CZP-randomized patients (17.4%) and 31 of 107 placebo-randomized patients (29.0%) had past uveitis history. During the 24-week double-blind phase, the rate of uveitis flares was lower in CZP (3.0 [95% confidence interval (95% CI) 0.6-8.8] per 100 patient-years) than in placebo (10.3 [95% CI 2.8-26.3] per 100 patient-years). All cases observed during the 24-week double-blind phase were in patients with a history of uveitis; in these patients, rates were similarly lower for CZP (17.1 [95% CI 3.5-50.1] per 100 patient-years) than placebo (38.5 [95% CI 10.5-98.5] per 100 patient-years). Rates of uveitis flares remained low up to week 96 (4.9 [95% CI 3.2-7.4] per 100 patient-years) and were similar between AS (4.4 [95% CI 2.3-7.7] per 100 patient-years) and nr-axial SpA (5.6 [95% CI 2.9-9.8] per 100 patient-years).ConclusionThe rate of uveitis flares was lower for axial SpA patients treated with CZP than placebo during the randomized controlled phase. Incidence of uveitis flares remained low to week 96 and was comparable to rates reported for AS patients receiving other anti-tumor necrosis factor antibodies.

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The observed alteration in BCL2 expression following lithium treatment is influenced by the choice of normalization method.

Publications

The observed alteration in BCL2 expression following lithium treatment is influenced by the choice of normalization method.

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