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hsa_circ_0015388 Reduces Macrophage Derived Reactive Oxygen Species in Crohn's Disease
Yuya Sugiyama1, Hiroaki Konishi2, Tatsuya Dokoshi3
1Division of Metabolism and Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2-1-1-1, Asahikawa Hokkaido, 078-8510, Japan.
Insights
Circular RNAs (circRNAs) are implicated in Crohn's disease (CD) pathogenesis. This study identifies hsa_circ_0015388 as a key circRNA in CD, which suppresses reactive oxygen species (ROS) production in macrophages.
Area of Science:
- Molecular Biology
- Immunology
- Gastroenterology
Background:
- Crohn's disease (CD) is a complex inflammatory bowel disease with unknown causes.
- Circular RNAs (circRNAs) are emerging as significant players in various disease pathologies.
- The specific role of circRNAs in CD pathogenesis remains largely unexplored.
Purpose of the Study:
- To investigate the differential expression of circRNAs in Crohn's disease patients.
- To identify specific circRNAs involved in the immune response within CD.
- To elucidate the functional role of a key circRNA in macrophage-mediated inflammation in CD.
Main Methods:
- RNA sequencing of terminal ileum biopsies from CD and non-CD individuals.
- Validation of differentially expressed circRNAs using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR).
- Functional analysis in macrophage-like THP-1 cells with circRNA downregulation, assessing reactive oxygen species (ROS) production, cytokine expression, and cell migration.
Main Results:
- 31 circRNAs were found to be significantly dysregulated between CD and non-CD groups.
- Hsa_circ_0015388 was significantly upregulated in CD patients and expressed in THP-1 cells.
- Downregulation of hsa_circ_0015388 in THP-1 cells increased ROS production and altered innate immune pathways, which was mitigated by TNFSF10 inhibition.
Conclusions:
- Hsa_circ_0015388 is dysregulated in Crohn's disease.
- Hsa_circ_0015388 is expressed in macrophages and negatively regulates ROS production via the TNFSF10 pathway.
- This study highlights hsa_circ_0015388 as a potential therapeutic target in CD by modulating macrophage ROS production.
Background:
Crohn's disease (CD) is a refractory inflammatory bowel disease with an unclear etiology. CircularRNA (circRNA) has been highlighted as a novel class of functional noncoding RNAs associated with the pathogenesis of various diseases. However, the functions of circRNA in CD remain unclear.
Methods:
Biopsies were obtained from noninflammatory sites in the terminal ileum of the CD group (n = 4) and non-CD group (n = 4) and analyzed for circRNA expression using RNA sequencing. The significantly altered circRNAs were validated in the CD group (n = 45) and non-CD group (n = 15) using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Transcriptome analysis was conducted using circRNA-downregulated macrophage-like THP-1 cells. Reactive oxygen species (ROS) levels, cytokine mRNA expression, phagocytosis, and migration were evaluated in circRNA-downregulated THP-1 cells.
Results:
CircularRNA sequencing analysis revealed significant differences in 31 circRNAs between the CD group and non-CD group. Quantitative reverse transcriptase-polymerase chain reaction analysis for each circRNA demonstrated significant upregulation of hsa_circ_0015388 in the CD group. Hsa_circ_0015388 was expressed in THP-1 cells, but not in HCEC-1CT and Caco-2/bbe. Transcriptome analysis in THP-1 cells transfected with scramble or hsa_circ_0015388 siRNA (small interfering RNA) showed a significant alteration in innate immune response related pathway. Reactive oxygen species production was significantly increased in the hsa_circ_0015388 downregulated THP-1 cells. Reactive oxygen species induction in the hsa_circ_0015388 knocked down THP-1 was diminished by the inhibition of TNFSF10.
Conclusion:
A comprehensive analysis of circRNA expression revealed that 31 circRNAs were dysregulated in the CD group. Hsa_circ_0015388 is expressed in macrophages and negatively regulates ROS function inhibiting the TNFSF10 pathway. This study first revealed that hsa_circ_0015388 plays a role in the pathogenesis of CD by suppressing ROS production in macrophages.
