RESUMO
Pleiotrophin (PTN) is a growth factor with both pro-angiogenic and limited pro-tumorigenic activity. We evaluated the potential for PTN to be used for safe angiogenic gene therapy using the full length gene and a truncated gene variant lacking the domain implicated in tumorigenesis. Mouse myoblasts were transduced to express full length or truncated PTN (PTN or T-PTN), along with a LacZ reporter gene, and injected into mouse limb muscle and myocardium. In cultured myoblasts, PTN was expressed and secreted via the Golgi apparatus, but T-PTN was not properly secreted. Nonetheless, no evidence of uncontrolled growth was observed in cells expressing either form of PTN. PTN gene delivery to myocardium, and non-ischemic skeletal muscle, did not result in a detectable change in vascularity or function. In ischemic hindlimb at 14 days post-implantation, intramuscular injection with PTN-expressing myoblasts led to a significant increase in skin perfusion and muscle arteriole density. We conclude that (1) delivery of the full length PTN gene to muscle can be accomplished without tumorigenesis, (2) the truncated PTN gene may be difficult to use in a gene therapy context due to inefficient secretion, (3) PTN gene delivery leads to functional benefit in the mouse acute ischemic hindlimb model.
Assuntos
Proteínas de Transporte/genética , Citocinas/genética , Terapia Genética , Isquemia/terapia , Músculo Esquelético/irrigação sanguínea , Fragmentos de Peptídeos/genética , Animais , Proteínas de Transporte/metabolismo , Movimento Celular , Transformação Celular Neoplásica/metabolismo , Células Cultivadas , Vasos Coronários/patologia , Citocinas/metabolismo , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático , Membro Posterior/irrigação sanguínea , Membro Posterior/patologia , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Masculino , Camundongos , Camundongos Nus , Camundongos SCID , Músculo Esquelético/patologia , Mioblastos/metabolismo , Mioblastos/transplante , Miocárdio/patologia , Miócitos de Músculo Liso/fisiologia , Neovascularização Fisiológica , Fragmentos de Peptídeos/metabolismoRESUMO
Delivery of bone marrow cells (BMCs) to the heart has substantially improved cardiac function in most rodent models of myocardial infarction (MI), but clinical trials of BMC therapy have led to only modest improvements. Rodent models typically involve intramyocardial injection of BMCs from distinct donor individuals who are healthy. In contrast, autologous BMCs from individuals after MI are used for clinical trials. Using BMCs from donor mice after MI, we discovered that recent MI impaired BMC therapeutic efficacy. MI led to myocardial inflammation and an increased inflammatory state in the bone marrow, changing the BMC composition and reducing their efficacy. Injection of a general anti-inflammatory drug or a specific interleukin-1 inhibitor to donor mice after MI prevented this impairment. Our findings offer an explanation of why human trials have not matched the success of rodent experiments and suggest potential strategies to improve the success of clinical autologous BMC therapy.
