Integrin β1 Gene Therapy Enhances in Vitro Creation of Tissue-Engineered Cartilage Under Periodic Mechanical Stress

Abstract

Background/Aims: Periodic mechanical stress activates integrin β1-initiated signal pathways to promote chondrocyte proliferation and matrix synthesis. Integrin β1 overexpression has been demonstrated to play important roles in improving the activities and functions of several non-chondrocytic cell types. Therefore, in the current study, we evaluated the effects of integrin β1 up-regulation on periodic mechanical stress-induced chondrocyte proliferation, matrix synthesis and ERK1/2 phosphorylation in chondrocyte monolayer culture, and evaluated the quality of tissue-engineered cartilage constructed in vitro under periodic mechanical stress combined with integrin β1 up-regulation. Methods and Results: Our results revealed that under periodic mechanical stress, pre-treatment with integrin β1-wild type vector significantly enhanced chondrocyte proliferation and matrix synthesis and promoted ERK1/2 phosphorylation in comparison to mock transfectants. Furthermore, when chondrocytes were seeded in PLGA scaffolds, more accumulated GAG and type II collagen tissue were detected after Lv-integrin β1 transfection compared with sham controls exposed to periodic mechanical stress. In contrast, in the Lv-shRNA-integrin β1 group, the opposite results were observed. Conclusion: Our findings collectively suggest that in addition to periodic mechanical stress, integrin β1 up-regulation in chondrocytes could further improve the quality of tissue-engineered cartilage.

Proteomic Analysis Reveals Grb2 as a Key Regulator of Periodic Mechanical Stress Transduction in Chondrocytes

“…We previously found that rabbit chondrocytes subjected to stress varying from 0–200 kPa at 0.1 Hz yielded the best quality tissue-engineered cartilage [40]. We accordingly used a pressure range of 0–200 kPa and 0.1 Hz frequency in the current study.…”

“…The GAG content of each group was recorded after 6 weeks, as described previously [40]. The samples were rinsed with double-distilled H2O and lyophilized for 12 h, followed by the addition of 1 mL cold H 2 O and incubation at 4°C in a microcentrifuge tube overnight.…”

Gene therapy for chondral and osteochondral regeneration: is the future now?

“…To overcome this last disadvantage, lentiviruses, belonging to a subclass of retrovirus family derived from the human immunodeficiency virus (HIV), have been proposed because they can transduce in non-dividing cells [76]. Lentivirus were employed for the delivery of sequence that codifies for BMPs [76], zinc-finger protein 145 (ZNF145) [77], IL10 [78] and Integrin-β [79] (Table 1). However, lentiviral vectors, similarly to retroviruses, favour gene integration, which might determine an insertional transformation and, subsequently, tumour formation.…”

“…Less is known about genes encoding for the cell signalling protein iHH [53,55], for ECM component (COMP) [19] and for integrin β1 [79] (Table 1). COMP is a multidomain homo-pentameric protein, which is an important regulator of collagen fiber assembly, interacting with other matrix proteins and inducing chondrocyte proliferation in vitro.…”

Periodic Mechanical Stress Stimulates Cav-1-Dependent IGF-1R Mitogenic Signals in Rat Chondrocytes Through ERK1/2

“…Periodic mechanical stress is advantageous to simulate in vivo physiological conditions for promoting chondrocyte proliferation [1,2]. However, few studies have addressed the mechanisms underlying the translation of such mechanical inputs into biochemical signaling events within the chondrocyte lineage.…”