MicroRNA Profiling Reveals Distinct Signatures in Degenerative Rotator Cuff Pathologies

Abstract

MicroRNAs (miRNAs) have emerged as key regulators orchestrating a wide range of inflammatory and fibrotic diseases. However, the role of miRNAs in degenerative shoulder joint disorders is poorly understood. The aim of this explorative case-control study was to identify pathology-related, circulating miRNAs in patients with chronic rotator cuff tendinopathy and degenerative rotator cuff tears (RCT). In 2017, 15 patients were prospectively enrolled and assigned to three groups based on the diagnosed pathology: (i) no shoulder pathology, (ii) chronic rotator cuff tendinopathy, and (iii) degenerative RCTs. In total, 14 patients were included. Venous blood samples ("liquid biopsies") were collected from each patient and serum levels of 187 miRNAs were determined. Subsequently, the change in expression of nine candidate miRNAs was verified in tendon biopsy samples, collected from patients who underwent arthroscopic shoulder surgery between 2015 and 2018. Overall, we identified several miRNAs to be progressively deregulated in sera from patients with either chronic rotator cuff tendinopathy or degenerative RCTs. Importantly, for the several of these miRNAs candidates repression was also evident in tendon biopsies harvested from patients who were treated for a supraspinatus tendon tear. As similar expression profiles were determined for tendon samples, the newly identified systemic miRNA signature has potential as novel diagnostic or prognostic biomarkers for degenerative rotator cuff pathologies. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. Inc. J Orthop Res 38:202-211, 2020.

Keywords: biomarker; circulating microRNA; rotator cuff; tendinopathy; tendon degeneration.

Figure 1

Magnetic resonance imaging of the affected shoulder. The oblique coronal imaging is shown on the top row and the sagittal images on the bottom row, respectively. (A) A full‐thickness rotator cuff tear with slight tendon retraction and mild muscle degeneration. (B) A chronic tendinopathy without any tearing of the supraspinatus tendon and muscle degeneration.

Figure 2

Principal component analysis (PCA). PCA was performed to assess clustering of patients based on their serum microRNA (miRNA) profiles reflected by principal components 1 and 2. (A) Clustering of samples based on the 50 most variant miRNAs in the data set based on the coefficient of variation (CV%). (B) Clustering of samples based on the 24 miRNAs differentially regulated miRNAs (p < 0.05) based on the comparison between degenerative rotator cuff tear (degRCT) and healthy controls (CTRL). [Color figure can be viewed at wileyonlinelibrary.com]

Figure 3

VENN overlap of microRNA (miRNA) lists derived from differential expression analysis. Six miRNAs were regulated in degenerative rotator cuff tears (degRCT) versus healthy controls (CTRL) and degRCT versus chronic tendinopathy (CT) (left, green box). Six miRNAs were regulated in degRCT versus CTRL and CT versus CTRL (right, brown box). [Color figure can be viewed at wileyonlinelibrary.com]

Figure 4

Scatterplots depicting the levels of six miRNAs that were found to be only downregulated in degenerative rotator cuff tear samples (degRCT), but not in healthy controls (CTRL) or chronic tendinopathy samples (CT).

Figure 5

Serum levels of microRNAs (miRNAs) commonly repressed in chronic tendinopathy (CT) as well as degenerative rotator cuff tear samples (degRCT) when compared with healthy controls (CTRL).

Figure 6

Comparison of serum expression levels of has‐miR‐29c and has‐miR‐29a between the three groups. Significant repression was found between healthy controls (CTRL) and patients with degenerative rotator cuff tears (degRCT), while the difference between CTRL and patients with chronic tendinopathy was not significant.

Figure 7

Change in microRNAs (miRNAs) expression in tissue specimens. The majority of the tested miRNAs were significantly repressed in biopsy samples harvested from patients undergoing rotator cuff surgery (n = 11; black gray bars) when compared with control samples (n = 8; black bars) (*p < 0.05; **p < 0.01; Mann–Whitney test).