MicroRNA transcriptome analysis on hypertrophy of ligamentum flavum in patients with lumbar spinal stenosis

Abstract

Abstract:Introduction: Molecular pathways involved in ligamentum flavum (LF) hypertrophy are still unclarified. The purpose of this study was to characterize LF hypertrophy by microRNA (miRNA) profiling according to the classification of lumbar spinal stenosis (LSS).Methods: Classification of patients with LSS into ligamentous and non-ligamentous cases was conducted by clinical observation and the morphometric parameter adopting the LF/spinal canal area ratio (LSAR) from measurements of magnetic resonance imaging (MRI) T2 weighed images. LF from patients with ligamentous stenosis (n=10) were considered as the degenerative hypertrophied samples, and those from patients with non-ligamentous LSS (n=7) and lumbar disc herniation (LDH, n=3) were used as non-hypertrophied controls. Profiling of miRNA from all samples was conducted by Agilent microarray. Microarray data analysis was performed with GeneSpring GX, and pathway analysis was performed using Ingenuity Pathway Analysis.Results: The mean LSAR in the ligamentous group was significantly higher than that in the control group (0.662±0.154 vs 0.301±0.068, p=0.0000171). Ten significantly differentially expressed miRNA were identified and taken as a signature of LF hypertrophy: nine miRNA showed down-regulated expression, and one showed up-regulated expression in the ligamentous LF. Among those, miR-423-5p (rs=-0.473, p<0.05), miR-4306 (rs=-0.628, p<0.01), miR-516b-5p (rs=-0.629, p<0.01), and miR-497-5p (rs=0.461, p<0.05) were correlated to the LSAR. Pathway analysis predicted aryl hydrocarbon receptor signaling (p<0.01), Wnt/β-catenin signaling (p<0.01), and insulin receptor signaling (p<0.05) as canonical pathways associated with the miRNA signature.Conclusions: Classification based on quantification of the MRI axial image is useful for studying hypertrophy of the LF. Aryl hydrocarbon receptor and Wnt/β-catenin signaling may be involved in LF hypertrophy.

Dysregulation of MicroRNAs in Hypertrophy and Ossification of Ligamentum Flavum: New Advances, Challenges, and Potential Directions

“…Based on transcriptome sequencing, deregulated miRNAs profiling in HLF patients was conducted by Mori et al in which they utilized the Agilent microarray and identified 10 DEMs in hypertrophied LF tissues (n = 10) vs. normal tissues (n = 10) (Mori et al, 2017). In this expression signature, nine miRNAs (miR-1228-3p, miR-1237, miR-30c-2-3p, miR-423-5p, miR-4306, miR-483-5p, miR-514b-5p, miR-516b-5p, and miR-765) were downregulated, and only one (miR-497-5p) was upregulated in the hypertrophied ligaments.…”

Ligamentum flavum fibrosis and hypertrophy: Molecular pathways, cellular mechanisms, and future directions

“…109 Moreover, microRNA transcriptome analysis showed that Aryl hydrocarbon receptor and Wnt/β-catenin signaling may also be involved in TGF-β1-induced LF fibrosis ( Figure 2). 110 Together, TGF-β1 not only activates the formation of ECM in fibroblast cells, it also increases the differentiation of fibroblast to myofibroblast by promoting or triggering the processes of producing ECM.…”

Amelioration of ligamentum flavum hypertrophy using umbilical cord mesenchymal stromal cell-derived extracellular vesicles

“…Our data also showed that TGF-β1 could effectively promote the expression of Col-I, α-SMA, and Col-III and result in LF cell fibrosis in a dose-dependent manner. According to previous literatures [ 11 , [43] , [44] , [45] ], 10 miRNAs relative to fibrosis were selected as candidates; the RT-qPCR validation of these candidates partially matched the results reported in a previous study [ 46 ]. Since the amelioration of LFH after the EV injection was found, we hypothesised that the miRNAs enriched in the EVs would take responsibility for this amelioration.…”