It has been demonstrated that adenoviral vectors can also induce immune responses to self-antigens 41. divided into DNA, viral, and cell SB 242084 vectors 10, 19. Among the BMP gene therapy vectors, human BMP adenoviral vectors (ADhBMPs) are very commonly used and have displayed strong osteogenic potentials in immunodeficient animals 1, 25. Nevertheless, the functions of ADhBMPs have proved to be significantly limited in immunocompetent animals 1, 25, 35, 38. All five human BMP adenoviral vectors (ADhBMPs 2, 4, 6, 7, and 9) have been shown to induce large volumes of ectopic bone formation in athymic nude (AN) rats. Bone volumes induced by these BMP vectors were best when ADhBMPs 4, 6, and 9 were used, followed by ADhBMP2 and, finally, by ADhBMP7. The osteogenic potentials of ADhBMPs 2, 4, and 7, however, were not shown in immunocompetent animals. In addition, bone volumes induced by ADhBMP6 were significantly smaller in immunocompetent animals than in immunodeficient animals. In contrast, bone formation induced by ADhBMP9 was comparable in AN and immunocompetent rats 25. These results may be related to different BMP transmission transduction pathways and the host immune response. The BMP family includes more than 30 users 9, 46. According to previous studies, BMPs combine with type 1 (Alk2, Alk3, and Alk6) and type 2 (BR2, ActR2, and ActR2B) receptors, activate the Smad and p38/MAPK transmission transduction pathways, and, finally, activate transcription of bone formation factors 36, 44. BMP2 and BMP4 combine with Alk3 and use Smad1, Smad5, or Smad8 to transduce signals 4, 31. BMP6 and BMP7 may strongly combine with Alk2 and weakly combine with Alk3 and Alk6. Their signals are mainly transferred with Smad5 and, possibly, with Smad1 but not with Smad8 11, 13. Compared with other BMPs, BMP9 uses a different type of receptor and transmission transduction pathway, the details of which are not yet obvious 30, 40. The functional performances of various BMP adenoviral vectors may reflect different mechanisms 20. On the other hand, the sources of BMP cDNAs may also cause the functional limitation of ADhBMPs in immunocompetent animals. We selected rat BMP4 and BMP6 to help us solution these questions. In the present study, two different units of experiments were designed and performed. In the first, rat In the second set of experiments, human cDNA was constructed to form a second-generation human BMP adenoviral vector ( [E1-,E2b-]ADhBMP). The viral vectors [E1-,E2b-]ADhBMP6, and [E1-,E2b-]ADGFP&BMP6 which include the green fluorescent protein [GFP] were tested in and models. The roles of the viral genome and the sources of BMP cDNA in the process of bone formation were determined in this study. 2. MATERIALS AND SB 242084 METHODS Cloning and identification of rat BMP4 and BMP6 cDNA coding sequences Total RNA was prepared from your spleen of a 2-month-old SD rat ATP7B by using an RNeasy Mini Kit (Qiagen, Valencia, CA) according to the manufacturer’s instructions. Rat and cDNAs made up of full coding sequences were generated SB 242084 by performing an RT-PCR with the OneStep RT-PCR Kit (Qiagen). The designs of the PCR primers were based on a known rat sequence and a partial rat sequence in which mouse and human sequences were inserted in places in which the SB 242084 rat sequence was not known 17, 22, 39. For and PCR SB 242084 products and the recombinant plasmids of pShuttle-rBMP4 and pShuttle-rBMP6 were prepared and sequenced (both strands) to ensure that the rat BMP inserts.
It has been demonstrated that adenoviral vectors can also induce immune responses to self-antigens 41