High cholesterol inhibits tendon‐related gene expressions in tendon‐derived stem cells through reactive oxygen species‐activated nuclear factor‐κB signaling

Abstract

Clinical studies have indicated that increased serum cholesterol levels raised the risk of tendinopathy in hypercholesterolemia, but the effect of cholesterol on tendon‐derived stem cells (TDSCs) and its underlying mechanism have not been studied. The purpose of this study is to investigate the association between cholesterol and tendinopathy in vitro and in vivo, and its underlying molecular mechanism as well. In TDSCs, the effect of cholesterol was assessed by quantitative polymerase chain reaction, western blot analysis, and immunofluorescence staining. Intracellular levels of reactive oxygen species (ROS) was detected, using flow cytometry. The link between nuclear factor (NF)‐κB signaling and the effect of cholesterol was evaluated using a representative IκB kinase (IKK) inhibitor, BAY 11‐7082. In addition, Achilles tendons from apolipoprotein E mice fed with a high‐fat diet were histologically assessed using hematoxylin and eosin staining and immunohistochemistry. We found that high cholesterol apparently lowered the expression of tendon cell markers (collagen 1, scleraxis, tenomodulin), and elevated ROS levels via the NF‐κB pathway both in vitro and in vivo. The ROS scavenger N‐acetylcysteine (NAC) and BAY 11‐7082 reversed the inhibiting effect of cholesterol on the tendon‐related gene expressions of TDSCs. Moreover, NAC blocked cholesterol‐induced phosphorylation of IκBα and p65. Significant histological alternation in vivo was shown in Achilles tendon in the hypercholesterolemic group. These results indicated that high cholesterol may inhibit the tendon‐related gene expressions in TDSCs via ROS‐activated NF‐кB signaling, implying pathogenesis of tendinopathy in hypercholesterolemia and suggesting a new mechanism underlying hypercholesterolemia‐induced tendinopathy.

Paternal Resistance Training Modulates Calcaneal Tendon Proteome in the Offspring Exposed to High-Fat Diet

“…On the other hand, an important finding of the current study was that SFO-HF demonstrated a decrease of proteins involved in tendon remodeling when compared with SFO-C group. Our results corroborate with transcriptome study which demonstrated that ApoE −/− associated with HF diet, promotes mRNA-level dysregulation of signaling pathways related with ECM synthesis, and repair in the tendon, suggesting mechanism of hypercholesterolemia-induced tendinopathy (Li et al, 2019). TGF-β superfamily orchestrates essential cellular processes that include proliferation, differentiation, and growth of the ECM (Klein et al, 2002).…”

High cholesterol induces apoptosis and autophagy through the ROS-activated AKT/FOXO1 pathway in tendon-derived stem cells

“…The viability and tenogenic differentiation of TDSCs are closely associated with the maintenance of the tendon microenvironment and the development of tendinopathy [8]. Because tendinopathy is closely correlated with hypercholesterolemia, we found that high cholesterol inhibits tendon-related gene expression in TDSCs [11]. However, the effect of cholesterol on the viability of TDSCs remains unknown.…”

“…Western blotting was performed based on a previously described protocol [11]. After the indicated stimulation, proteins from TDSCs were extracted with RIPA buffer containing PMSF, and protease and phosphatase inhibitor cocktails.…”

“…A moderate level of ROS promotes cell proliferation and differentiation, while excessive amounts of ROS induce cell apoptosis or autophagy due to oxidative damage to lipids, proteins, and DNA [18]. We have already found that cholesterol upregulates ROS levels in TDSCs [11]. ROS affect a variety of signaling pathways, including the AKT/ FOXO1 signal pathway [19].…”

Systematic analysis of the molecular pathophysiology of tenosynovitis: promise for using chondroitin sulfate and glucosamine sulfate

“…Например, высокий уровень холестерина у мышей, активируя передачу сигналов по каскаду NF-κB, ингибирует экспрессию генов синтеза соединительной ткани в стволовых клетках сухожилий. У мышей, в рационе которых было значительное содержание насыщенных жиров, высокий уровень хо-лестерина увеличивал концентрацию АФК, снижал экспрессию коллагена 1 и теномодулина [30].…”