Open Access

ARTICLE

Revisiting miR-155 in intervertebral disc degeneration: blood cell signature and local cell-free profiles

ZHIHENG LIU^1,2, ZHEN SUN³, ZHONGYUAN WAN⁴, HAIQIANG WANG^2,*

1 Department of Cardiac Surgery, Xijing Hospital, Air Force Medical University, Xi’an, 710032, China
2 Institute of Integrative Medicine, Shaanxi University of Chinese Medicine, Xi’an, 712046, China
3 Department of Orthopedics, Xijing Hospital, Air Force Medical University, Xi’an, 710032, China
4 Department of Orthopedics, Seventh Medical Center of General Hospital of PLA, Beijing, 100700, China

* Corresponding Author: HAIQIANG WANG,

(This article belongs to this Special Issue: Noncoding RNAs & Associated Human Diseases)

BIOCELL 2022, 46(2), 511-517. https://doi.org/10.32604/biocell.2021.016194

Received 16 February 2021; Accepted 26 March 2021; Issue published 20 October 2021

Abstract

We unraveled the expression profiles of coding-noncoding RNAs in intervertebral disc degeneration (IDD). However, it remains elusive regarding miR-155 expression in peripheral blood mononuclear cells (PBMCs) and local extracellular space in IDD. The study aimed for investigating the miR-155 expression of PBMCs, extracellular miRNAs (ex-miRNAs) of human nucleus pulposus (NP) tissues, and morphological changes of cell death in the IDD process. Here, we harvested peripheral blood and NP samples from scoliosis and IDD patients as control and degenerative groups, respectively. Then standard Ficoll density-gradient centrifugation was used to isolate PBMCs. The two subpopulations of PBMCs were divided based on the cellular difference in adherence, i.e., monocytes/ macrophages and lymphocytes. Quantitative real-time PCR was used to evaluate miR-155 relative expression in PBMCs. ex-miRNAs were screened by comparison between GSE19943, GSE63492, and extracellular RNA (exRNA) atlas. The morphological changes of cell death subtypes in IDD were observed in transmission electron microscopy (TEM). Results indicate that the lower expression of miR-155 in PBMCs from IDD patients ascribed to alterations in monocytes/macrophages. Moreover, we identified 594 shared hsa-miRNAs as the intracellular miRNA expression profile and 258 miRNAs as the ex-miRNA expression profile in human NP tissue. miR-155 was amongst intracellular miRNAs in NP. TEM observation presented multiple endocytic secretory vesicles within human NP cells, implicating exosome transporting machinery. Typical necroptosis and pyroptosis were noted in human NP. Collectively, this study reveals miR-155 expression in PBMCs from IDD patients. Moreover, we propose ex-miRNA expression profile and necroptosis/pyroptosis in human NP tissue, shedding novel light on the etiology of IDD.

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