Transcriptome sequencing wide functional analysis of human mesenchymal stem cells in response to TLR4 ligand.

Sun Hwa Kim,Kyoung Hwa Jung,Kyoung Sun Park,Bert Binas,Amitabh Das,Young Seek Lee,Young Gyu Chai,Jin Choul Chai,Mi Ran Choi

doi:10.1038/srep30311

Sun Hwa Kim, Kyoung Hwa Jung + Show 7 more

Open Access

https://doi.org/10.1038/srep30311

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Journal: Scientific Reports	Publication Date: Jul 1, 2016
Citations: 29	License type: CC BY 4.0

Affiliation: Hanyang University

Abstract

Due to their multipotentiality and immunomodulation, human mesenchymal stem cells (hMSCs) are widely studied for the treatment of degenerative and inflammatory diseases. Transplantation of hMSCs to damaged tissue is a promising approach for tissue regeneration. However, the physiological mechanisms and regulatory processes of MSC trafficking to injured tissue are largely unexplored. Here, we evaluated the gene expression profile and migratory potential of hMSCs upon stimulation with the TLR4 ligand lipopolysaccharide (LPS). Using RNA sequencing, we identified unique induction patterns of interferon stimulated genes, cytokines and chemokines involved in chemotaxis and homing. The −950 to +50 bp regions of many of these LPS-responsive genes were enriched with putative binding motifs for the transcription factors (TFs) interferon regulatory factor (IRF1) and nuclear factor kappa B (NF-κB1, REL), which were also induced by LPS along with other TFs. Chromatin immunoprecipitation assays showed that IRF1 bound within their target genes promoter region. In addition, IRF1 attenuation significantly down-regulated interferon stimulated genes as well as key cytokines. Furthermore, using pharmacological inhibitors, we showed that the NF-κB and phosphatidylinositol 3-kinase (PI3K) pathways regulate the migratory and cytokines/chemokines response to LPS. These unprecedented data suggest that IRF1 and NF-κB orchestrate the TLR4-primed immunomodulatory response of hMSCs and that this response also involves the PI3K pathway.

Highlights

Differentiation factor 88 (MyD88)-dependent signaling pathways activates downstream effectors including NF-κB, mitogen-activated protein kinase (MAPK), and PI3K, which induces inflammatory cytokine production[11,12]
We observed strong enrichments of gene ontology (GO) terms for the NF-κB1 and IRF1-regulated transcripts associated with the response to wounding and immune response in TLR4-primed human bone marrow MSCs (hMSCs) (Fig. 5I). These findings suggest that NF-κB 1 and IRF1 might be involved in the regulation of chemotaxis response in TLR4-primed hMSCs
This study is to comprehensively describe the gene expression profiles of TLR4-primed hMSCs

Summary

Introduction

Differentiation factor 88 (MyD88)-dependent signaling pathways activates downstream effectors including NF-κB, mitogen-activated protein kinase (MAPK), and PI3K, which induces inflammatory cytokine production[11,12]. We hypothesized that gene expression profiling of TLR4-primed MSCs would provide clues to the molecular pathways involved in MSCs migration. We performed gene array and comparative gene expression profiling of hMSCs that were treated with the well-characterized TLR4 ligand lipopolysaccharide (LPS)[17]. To this end, we used RNA sequencing (RNA-seq), a technique that, unlike microarrays, provides unbiased profiling and the ability to identify novel transcribed regions and can be extremely accurate if a sufficient level of coverage is obtained[18,19]. The results deliver valuable information on molecular mechanisms behind hMSCs and TLR4-primed chemokines for stem cell migration, which will help to understand and utilize their functional plasticity in inflammation and immunomodulation

Results

Discussion

Conclusion