TNF-α mediates diabetes-enhanced chondrocyte apoptosis during fracture healing and stimulates chondrocyte apoptosis Through FOXO1

Abstract

To gain insight into the effect of diabetes on fracture healing, experiments were carried out focusing on chondrocyte apoptosis during the transition from cartilage to bone. Type 1 diabetes was induced in mice by multiple low-dose streptozotocin injections, and simple transverse fractures of the tibia or femur was carried out. Large-scale transcriptional profiling and gene set enrichment analysis were performed to examine apoptotic pathways on total RNA isolated from fracture calluses on days 12, 16, and 22, a period of endochondral bone formation when cartilage is resorbed and chondrocyte numbers decrease. Tumor necrosis factor α (TNF-α) protein levels were assessed by ELISA and caspase-3 by bioactivity assay. The role of TNF was examined by treating mice with the TNF-specific inhibitor pegsunercept. In vitro studies investigated the proapoptotic transcription factor FOXO1 in regulating TNF-induced apoptosis of chondrogenic ATDC5 and C3H10T1/2 cells as representative of differentiated chondrocytes, which are important during endochondral ossification. mRNA profiling revealed an upregulation of gene sets related to apoptosis in the diabetic group on day 16 when cartilage resorption is active but not day 12 or day 22. This coincided with elevated TNF-α protein levels, chondrocyte apoptosis, enhanced caspase-3 activity, and increased FOXO1 nuclear translocation (p < .05). Inhibition of TNF significantly reduced these parameters in the diabetic mice but not in normoglycemic control mice (p < .05). Silencing FOXO1 using siRNA in vitro significantly reduced TNF-induced apoptosis and caspase activity in differentiated chondrocytes. The mRNA levels of the proapoptotic genes caspase-3, caspase-8, caspase-9, and TRAIL were significantly reduced with silencing of FOXO1 in chondrocytic cells. Inhibiting caspase-8 and caspase-9 significantly reduced TNF-induced apoptosis in chondrogenic cells. These results suggest that diabetes causes an upregulation of proapoptotic genes during the transition from cartilage to bone in fracture healing. Diabetes increased chondrocyte apoptosis through a mechanism that involved enhanced production of TNF-α, which stimulates chondrocyte apoptosis and upregulates mRNA levels of apoptotic genes through FOXO1 activation. © 2010 American Society for Bone and Mineral Research

Shown for reading. Its publisher allows quoting it, not republishing it.

References 54

1. 1.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

2. 2.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

3. 3.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

4. 4.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

5. 5.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

6. 6.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

7. 7.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

8. 8.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

9. 9.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

10. 10.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

11. 11.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

12. 12.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

13. 13.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

14. 14.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

15. 15.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

16. 16.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

17. 17.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

18. 18.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

19. 19.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

20. 20.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

21. 21.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

22. 22.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

23. 23.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

24. 24.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

25. 25.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

26. 26.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

27. 27.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

28. 28.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

29. 29.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

30. 30.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

31. 31.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

32. 32.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

33. 33.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

34. 34.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

35. 35.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

36. 36.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

37. 37.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

38. 38.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

39. 39.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

40. 40.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

41. 41.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

42. 42.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

43. 43.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

44. 44.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

45. 45.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

46. 46.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

47. 47.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

48. 48.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

49. 49.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

50. 50.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

51. 51.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

52. 52.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

53. 53.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

54. 54.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

Cited by papers we hold 5

• Impact of Diabetes Mellitus on Bone Health · 2019
  No notice
• The Impact of Type 2 Diabetes on Bone Fracture Healing · 2018
  No notice
• The Role of the Immune Cells in Fracture Healing · 2018
  No notice
• FOXO Transcription Factors: Their Clinical Significance and Regulation · 2014
  No notice
• Role of Forkhead Transcription Factors in Diabetes-Induced Oxidative Stress · 2012
  No notice

Reads

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.