RESUMEN
OBJECTIVE: Monocyte chemoattractant protein-1 (MCP-1) is a C-C chemokine that is known as an inflammatory/arteriogenic factor. Angiogenesis contributes to the inflammatory process; however, the molecular and cellular mechanisms of the links among the inflammatory pathway, arteriogenesis, and angiogenesis have not been well elucidated. METHODS AND RESULTS: Using murine models of fibroblast growth factor-2 (FGF-2)-mediated therapeutic neovascularization, we here show that FGF-2 targets nonendothelial mesenchymal cells (NEMCs) enhancing both angiogenic (vascular endothelial growth factor [VEGF]) and arteriogenic (MCP-1) signals via independent signal transduction pathways. Severe hindlimb ischemia stimulated MCP-1 expression that was strongly enhanced by FGF-2 gene transfer, and a blockade of MCP-1 activity via a dominant negative mutant as well as a deficiency of its functional receptor CCR2 resulted in the diminished recovery of blood flow attributable to adaptive and therapeutic neovascularization. Tumor necrosis factor (TNF)-alpha stimulated MCP-1 expression in all cell types tested, whereas FGF-2-mediated upregulation of MCP-1 was found only in NEMCs but not in others, a finding that was not affected by VEGF in vitro and in vivo. CONCLUSIONS: These results indicate that FGF-2 targets NEMCs independently, enhancing both angiogenic (VEGF) as well as inflammatory/arteriogenic (MCP-1) pathways. Therefore, MCP-1/CCR2 plays a critical role in adaptive and FGF-2-mediated therapeutic neovascularization.
Asunto(s)
Quimiocina CCL2/metabolismo , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Mesodermo/citología , Mesodermo/metabolismo , Neovascularización Fisiológica , Adaptación Fisiológica , Animales , Arterias/crecimiento & desarrollo , Factor 2 de Crecimiento de Fibroblastos/genética , Técnicas de Transferencia de Gen , Miembro Posterior/irrigación sanguínea , Mediadores de Inflamación/metabolismo , Isquemia/metabolismo , Isquemia/fisiopatología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Proteínas Quinasas Activadas por Mitógenos/metabolismo , FN-kappa B/metabolismo , Proteína Quinasa C/metabolismo , Receptores CCR2 , Receptores de Quimiocina/metabolismo , Flujo Sanguíneo Regional , Transducción de Señal , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Myocardial mitochondrial DNA (mtDNA) copy number decreases in heart failure. In post-myocardial infarction mice, increasing mtDNA copy number by overexpressing mitochondrial transcription factor attenuates mtDNA deficiency and ameliorates pathological remodeling thereby markedly improving survival. However, the functional significance of increased mtDNA copy number in hypertensive heart disease remains unknown. We addressed this question using transgenic mice that overexpress Twinkle helicase (Twinkle; Tg), the mtDNA helicase, and examined whether Twinkle overexpression protects the heart from left ventricular (LV) remodeling and failure after pressure overload created by transverse aortic constriction (TAC). Twinkle overexpression increased mtDNA copy number by 2.2 ± 0.1-fold. Heart weight, LV diastolic volume and wall thickness were comparable between Tg and wild type littermates (WT) at 28 days after TAC operation. LV end-diastolic pressure increased in WT after TAC (8.6 ± 2.8 mmHg), and this increase was attenuated in Tg (4.6 ± 2.6 mmHg). Impaired LV fractional shortening after TAC operation was also suppressed in Tg, as measured by echocardiography (WT: 16.2 ± 7.2% vs Tg: 20.7 ± 6.2%). These LV functional improvements were accompanied by a decrease in interstitial fibrosis (WT: 10.6 ± 1.1% vs Tg: 3.0 ± 0.6%). In in vitro studies, overexpressing Twinkle using an adenovirus vector in cultured cardiac fibroblasts significantly suppressed mRNA of collagen 1a, collagen 3a and connective tissue growth factor, and angiotensin II-induced transforming growth factor ß1 expression. The findings suggest that Twinkle overexpression prevents LV function deterioration. In conclusion, Twinkle overexpression increases mtDNA copy number and ameliorates the progression of LV fibrosis and heart failure in a mouse pressure overload model. Increasing mtDNA copy number by Twinkle overexpression could be a novel therapeutic strategy for hypertensive heart disease.
Asunto(s)
ADN Helicasas/genética , Fibrosis/patología , Expresión Génica/genética , Insuficiencia Cardíaca/patología , Proteínas Mitocondriales/genética , Animales , Aorta/patología , Constricción , Variaciones en el Número de Copia de ADN/genética , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Ecocardiografía/métodos , Fibrosis/genética , Corazón , Insuficiencia Cardíaca/genética , Hipertrofia Ventricular Izquierda/genética , Hipertrofia Ventricular Izquierda/patología , Masculino , Ratones , Ratones Transgénicos/genética , Presión , Función Ventricular Izquierda/genética , Remodelación Ventricular/genéticaRESUMEN
The overexpression of mitochondrial transcription factor A (TFAM) attenuates the decrease in mtDNA copy number after myocardial infarction, ameliorates pathological hypertrophy, and markedly improves survival. However, non-transgenic strategy to increase mtDNA for the treatment of pathological hypertrophy remains unknown. We produced recombinant human TFAM protein (rhTFAM). rhTFAM rapidly entered into mitochondria of cultured cardiac myocytes. rhTFAM increased mtDNA and abolished the activation of nuclear factor of activated T cells (NFAT), which is well known to activate pathological hypertrophy. rhTFAM attenuated subsequent morphological hypertrophy of myocytes as well. rhTFAM would be an attractive molecule in attenuating cardiac pathological hypertrophy.