Department of Orthopedic Surgery, Kaohsiung Chang Gung Memorial Hospital, Taiwan.
Department of Medicine, Division of Cardiology, Kaohsiung Chang Gung Memorial Hospital, Taiwan.
J Bone Joint Surg Am. 2022 Apr 6;104(Suppl 2):2-12. doi: 10.2106/JBJS.20.00465.
Reduced nitric oxide synthase (NOS) activity and decreased reparative potentials in stem cells may be involved in the pathogenesis of osteonecrosis of the femoral head (ONFH), but the underlying mechanism is not clear. Ankyrin, a cytoskeletal protein, can promote NOS expression and many cellular functions when it interacts with the CD44 receptors on the stem cells. This study investigated whether ankyrin is involved in the pathogenesis of ONFH.
Bone marrow stem cells (BMSCs) from ONFH patients were compared with cells from patients with proximal femoral fracture and BMSC cell lines (PT-2501, Lonza, NC, USA). Differences in the expression levels and downstream signal pathway of ankyrin-Akt-eNOS in BMSCs were studied between ONFH and control. The involvement of ankyrin in the signal cascade, cell proliferation, and differentiation were further investigated by silencing ankyrin using small interfering (si)RNA.
We found the basal mRNA levels of ankyrin and CD44 in BMSCs from the ONFH group were significantly lower as compared with those from the control group. The signal transduction of CD44-ankyrin-Akt-eNOS was significantly repressed in the ONFH group as compared with the control group after hyaluronic acid treatment. Knockdown of ankyrin by siRNA could attenuate the eNOS signaling as well as the BMSCs proliferation and osteogenic differentiation. The proliferation ability and osteogenic differentiation potential of the BMSCs from the ONFH group were significantly reduced as compared with the control group, but they can be enhanced to the baseline levels of the control group by hyaluronic acid treatment.
The aberrant eNOS signaling, reduced cell proliferation, and osteogenic differentiation potential in BMSCs from ONFH patients are associated with the decreased ankyrin expression.
Altered signal transduction, proliferation, and osteogenic differentiation ability in BMSCs may be involved in the pathogenesis of ONFH. These need further studies especially in BMSC-based cell therapy.
一氧化氮合酶（NOS）活性降低和干细胞修复潜能下降可能与股骨头坏死（ONFH）的发病机制有关，但具体机制尚不清楚。锚蛋白是一种细胞骨架蛋白，当它与干细胞上的 CD44 受体相互作用时，可以促进 NOS 的表达和许多细胞功能。本研究旨在探讨锚蛋白是否参与了 ONFH 的发病机制。
比较了 ONFH 患者骨髓间充质干细胞（BMSCs）与股骨近端骨折患者和 BMSC 细胞系（Lonza，NC，美国 PT-2501）的细胞之间的锚蛋白-Akt-eNOS 在 BMSCs 中的表达水平和下游信号通路的差异。通过使用小干扰（si）RNA 沉默锚蛋白进一步研究了锚蛋白在信号级联、细胞增殖和分化中的作用。
我们发现，与对照组相比，ONFH 组 BMSCs 的锚蛋白和 CD44 的基础 mRNA 水平明显降低。与对照组相比，透明质酸处理后 ONFH 组的 CD44-锚蛋白-Akt-eNOS 信号转导明显受到抑制。siRNA 敲低锚蛋白可减弱 eNOS 信号以及 BMSCs 的增殖和成骨分化。与对照组相比，ONFH 组 BMSCs 的增殖能力和成骨分化潜能明显降低，但经透明质酸处理后可增强至对照组的基线水平。
ONFH 患者 BMSCs 中异常的 eNOS 信号、增殖能力降低和成骨分化潜能与锚蛋白表达降低有关。
BMSCs 中信号转导、增殖和成骨分化能力的改变可能与 ONFH 的发病机制有关。这些需要进一步研究，特别是在基于 BMSC 的细胞治疗中。
