GSK-3β and β-Catenin Signaling Pathway is Involved in Myofibroblast Transition of Ligamentum Flavum in Lumbar Spinal Stenosis Patients

Abstract

Study Design. Histologic analysis of the ligamentum flavum (LF) in the lumbar spine. Objective. The objective of this study is to investigate the levels of glycogen synthase kinase-3β (GSK-3β) and β-catenin in the LF tissue of patients with lumbar spinal stenosis (LSS). Summary of Background Data. The hypertrophy of the LF is the primary cause of the progression of LSS. Recently, Wnt signaling has been proposed as one of the molecular processes contributing to LF hypertrophy. GSK-3β and β-catenin are recognized to play a crucial part in the control of this signaling pathway. Materials and Methods. From May 2020 to July 2022, LF from 51 LSS patients (LSS group) and 18 lumbar disc herniation patients (control group) were prospectively collected during surgery. Histologic analysis was investigated to confirm the progression of LF fibrosis. The levels of α-smooth muscle actin, phosphorylation of GSK-3β (p-GSK-3β; inactive form), and β-catenin were analyzed in LF with Western blot analysis to reveal the GSK-3β/β-catenin signaling pathway. Continuous variables are expressed as mean±SD and compared using the student t test. Categorical variables are compared using the χ2 test or Fisher exact test, as appropriate. To determine the association between p-GSK-3β and LF thickness, the Pearson correlation coefficient was calculated based on the results of Western blot analysis. Results. The LSS group was older and had thicker LF than the controls. The LSS group showed increased collagen fiber and cellularity than the controls. The levels of α-smooth muscle actin, p-GSK-3β, and β-catenin in the LF of the LSS group were significantly higher than that of the control group. There was a strong positive correlation between p-GSK-3β (Ser9) level and LF thickness in LSS patients (r=0.69, P=0.01). Conclusion. This research proposes a molecular mechanism for the pathogenesis of LF hypertrophy in LSS. Specifically, GSK-3β/β-catenin signaling appears to be related to LF hypertrophy in LSS and a positive correlation exists between p-GSK-3β level and LF thickness. Level of Evidence. Level 3.