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Updated: Jul 10, 2026
Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection
Published on: February 17, 2015
miR-363-5p- and IL-34-mediated modulation of pacemaker channel, HCN4, on iPSC-CM: Translation into the human sinus
Zeyuan Yin1, Tong Fu2, Lu Fu3
1Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Department of Cardiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; The First Clinical Medical School, Xuzhou Medical University, Xuzhou, China; Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.
Background:
The human sinus node (SN) contains cardiac fibroblasts and resident macrophages, with microRNAs (miRNAs) and interleukins as regulators of SN function. However, the mechanisms by which they influence heart rate remain unclear.
Objective:
This study aimed to investigate the SN microenvironment, encompassing miRNAs, interleukins, macrophages, and fibroblasts and modulating induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and hence beating rate.
Methods:
Multiomics analysis was conducted to compare human SN with the right atria. Human iPSC-CMs were cocultured with M2-type macrophages (M2s) and fibroblasts. Mechanistic studies involved the application of interleukin 34 (IL-34) and the silencing or overexpression of colony-stimulating factor 1 receptor and signal transducer and activator of transcription 3. Messenger RNA-miRNA interactions were predicted using the Ingenuity Pathway Analysis. miR-363-5p was applied to 3 cell lines and a coculture system and, along with IL-34, was tested in human serum samples.
Results:
M2 and fibroblast markers were identified. Coculturing iPSC-CMs with M2s induced a more nodal-like phenotype. Elevated IL-34 in the coculture medium suggested that M2s may secrete IL-34, driving these nodal-like features. IL-34 promoted a nodal-like phenotype in iPSC-CMs by upregulating hyperpolarization-activated cyclic nucleotide-gated channel subtype 4 expression probably through colony-stimulating factor 1 receptor/signal transducer and activator of transcription 3 signaling. Three key miRNAs were identified, with miR-363-5p inhibiting the differentiation of macrophages into the M2 phenotype. The nodal-like shift of iPSC-CMs in the coculture system was reversed by miR-363-5p. Although miR-363-5p (together with miR-486-3p) was highly expressed, IL-34 was reduced in aged individuals with SN dysfunction.
Conclusion:
M2s contribute to the SN microenvironment by secreting IL-34 and thus enhance SN function by upregulating hyperpolarization-activated cyclic nucleotide-gated channel subtype 4. Elevated miR-363-5p, seen in age-related SN dysfunction, may reverse these effects.
Insights
Macrophages and interleukin-34 (IL-34) enhance sinus node (SN) function by promoting a nodal-like phenotype. However, elevated miR-363-5p in aging may reverse these beneficial effects, impacting heart rate regulation.
Area of Science:
- Cardiovascular Biology
- Cellular and Molecular Medicine
- Regenerative Medicine
Background:
- The human sinus node (SN) microenvironment involves cardiac fibroblasts and macrophages, with microRNAs (miRNAs) and interleukins regulating its function.
- Mechanisms by which these factors influence heart rate are not fully understood.
Purpose of the Study:
- Investigate the role of the SN microenvironment, including miRNAs, interleukins, macrophages, and fibroblasts.
- Determine their impact on induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and heart rate modulation.
Main Methods:
- Performed multiomics analysis comparing human SN and right atria.
- Cocultured human iPSC-CMs with M2-type macrophages (M2s) and fibroblasts.
- Investigated interleukin 34 (IL-34) signaling pathways and miRNA effects (miR-363-5p) in cellular and human serum samples.
Main Results:
- M2 macrophages and fibroblasts were identified in the SN.
- Coculture with M2s induced a nodal-like phenotype in iPSC-CMs, associated with elevated IL-34 secretion by M2s.
- IL-34 promoted this phenotype via CSF1R/STAT3 signaling, upregulating HCN4. miR-363-5p inhibited M2 differentiation and reversed the nodal-like shift; it was elevated with reduced IL-34 in aged individuals with SN dysfunction.
Conclusions:
- M2 macrophages contribute to SN function by secreting IL-34, enhancing SN activity through HCN4 upregulation.
- Elevated miR-363-5p in age-related SN dysfunction may counteract these effects, potentially impairing heart rate regulation.
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