Functional characterization of the disease-associated CCL2 rs1024611G-rs13900T haplotype: The role of the RNA-binding protein HuR

  1. Feroz Akhtar
  2. Joselin Hernandez Ruiz
  3. Ya-Guang Liu
  4. Roy G. Resendez
  5. Denis Feliers
  6. Liza D. Morales
  7. Alvaro Diaz-Badillo
  8. Donna M. Lehman
  9. Rector Arya
  10. Juan Carlos Lopez-Alvarenga
  11. John Blangero
  12. Ravindranath Duggirala
  13. Srinivas Mummidi

  • Curated by eLife

    eLife logo

    eLife assessment

    CCL2 is a chemokine known to have relevant immune cell chemoattractant properties, and it is believed to play a role in several chronic inflammatory diseases. The RNA-binding protein HuR controls the stability and translation of CCL2 mRNA. This paper presents solid evidence that a relatively common genetic variant tied to several disease phenotypes affects the interaction between the mRNA of CCL2 and the RNA-binding protein HuR. As CCL2 is believed to be relevant for leukocyte migration in various conditions, including chronic inflammation and cancer, this is an important finding that may be relevant to a broad audience.

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

CC-chemokine ligand 2 (CCL2) is involved in the pathogenesis of several diseases associated with monocyte/macrophage recruitment, such as HIV-associated neurocognitive disorder (HAND), tuberculosis, and atherosclerosis. The rs1024611 (alleles:A>G; G is the risk allele) polymorphism in the CCL2 cis -regulatory region is associated with increased CCL2 expression in vitro and ex vivo, leukocyte mobilization in vivo, and deleterious disease outcomes. However, the molecular basis for the rs1024611-associated differential CCL2 expression remains poorly characterized. It is conceivable that genetic variant(s) in linkage disequilibrium (LD) with rs1024611 could mediate such effects. Previously, we used rs13900 (alleles: C>T) in the CCL2 3’ untranslated region (3’ UTR) that is in perfect LD with rs1024611 to demonstrate allelic expression imbalance (AEI) of CCL2 in heterozygous individuals. Here we tested the hypothesis that the rs13900 could modulate CCL2 expression by altering mRNA turnover and/or translatability. The rs13900 T allele conferred greater stability to the CCL2 transcript when compared to the rs13900 C allele. The rs13900 T allele also had increased binding to Human Antigen R (HuR), an RNA-binding protein, in vitro and ex vivo. The rs13900 alleles imparted differential activity to reporter vectors and influenced the translatability of the reporter transcript. We further demonstrated a role for HuR in mediating allele-specific effects on CCL2 expression in overexpression and silencing studies. The presence of the rs1024611G-rs13900T conferred a distinct transcriptomic signature related to inflammation and immunity. Our studies suggest that the differential interactions of HuR with rs13900 could modulate CCL2 expression and explain the interindividual differences in CCL2-mediated disease susceptibility.

Article activity feed

  1. Version published to 10.7554/elife.93108.1 on eLife
  2. Version published to 10.7554/elife.93108 on eLife
  3. eLife

    eLife assessment

    CCL2 is a chemokine known to have relevant immune cell chemoattractant properties, and it is believed to play a role in several chronic inflammatory diseases. The RNA-binding protein HuR controls the stability and translation of CCL2 mRNA. This paper presents solid evidence that a relatively common genetic variant tied to several disease phenotypes affects the interaction between the mRNA of CCL2 and the RNA-binding protein HuR. As CCL2 is believed to be relevant for leukocyte migration in various conditions, including chronic inflammation and cancer, this is an important finding that may be relevant to a broad audience.

  4. eLife

    Reviewer #1 (Public Review):

    Summary:
    This paper presents evidence that a relatively common genetic variant tied to several disease phenotypes affects the interaction between the mRNA of CCL2 and the RNA binding protein HuR. CCL2 is an immune cell chemoattractant protein.

    Strengths:
    The study is well conducted with relevant controls. The techniques are appropriate, and several approaches provided concordant results that were generally supportive of the conclusions reached. The impact of this work, identifying a genetic variant that works by altering the binding of an RNA-regulatory protein, has important implications given that the HuR protein could be a drug target to improve its function and override this genetic change. This could have important implications for a number of diseases where this genetic variant contributes to disease risk.

    Weaknesses:
    The authors need to do a better job of citing prior work. Certain details of the experimental protocols need to be further elaborated or clarified to contextualize the significance of the findings, Some of the findings need to be better described.

  5. eLife

    Reviewer #2 (Public Review):

    This study focuses on the differential binding of the RNA-binding protein HuR to CCL2 transcript (genetic variants rs13900 T or C). The study explores how this interaction influences the stability and translation of CCL2 mRNA. Employing a combination of bioinformatics, reporter assays, binding assays, and modulation of HuR expression, the study proposes that the rs13900T allele confers increased binding to HuR, leading to greater mRNA stability and higher translational efficiency. These findings indicate that rs13900T allele might contribute to heightened disease susceptibility due to enhanced CCL2 expression mediated by HuR. The study is interesting but needs appropriate experimental design and further strengthening. In its current form, the study suffers from several critical issues, including inadequate experimental design and the absence of control groups in key experiments.

  6. Version published to 10.1101/2023.10.31.564937v1 on bioRxiv