El factor de crecimiento queratinocítico humano recombinante induce la progresión de la supervivencia celular mediada por Akt en ratones enfisematosos / Recombinant Human Keratinocyte Growth Factor Induces Akt Mediated Cell Survival Progression in Emphysematous Mice

Introducción: El enfisema se ha asociado a una disminución de la expresión de VEGF y VEGFR-2 y a la presencia de un número elevado de células alveolares apoptósicas. El factor de crecimiento queratinocítico estimula la síntesis de VEGF, lo cual proporciona, a su vez, un mantenimiento de la estructura pulmonar normal a través de la vía de Akt. En este estudio hemos investigado el posible papel del rHuKGF en la mejora de la falta de regulación de la vía de supervivencia celular mediada por Akt en ratones enfisematosos. Métodos: Se establecieron 3 grupos experimentales: grupos de enfisema, tratamiento y control. Los pulmones de los ratones se trataron terapéuticamente en 3 ocasiones mediante la instilación orofaríngea de 10 mg de rHuKGF/kg de peso corporal tras la inducción del enfisema mediante elastasa pancreática porcina. Posteriormente, se obtuvo tejido pulmonar de los ratones para la realización de exámenes de histopatología y biología molecular. Resultados y discusión: Las microfotografías de histopatología y el análisis del índice de destrucción han mostrado que el agrandamiento del espacio aéreo inducido por la elastasa y la pérdida de alvéolos se recuperaron en el grupo de tratamiento. El rHuKGF estimula la producción de VEGF, que a su vez induce la vía de supervivencia celular mediada por Akt en los pulmones enfisematosos. Se produjo un aumento significativo de la expresión de mRNA de VEGF, VEGFR, PI3K y Akt, mientras que hubo una disminución notable de Pten, caspasa-9 y Bad en el grupo de tratamiento en comparación con el grupo de enfisema, y los resultados fueron comparables a los del grupo de control. Además, la expresión de VEGF a nivel proteico concordaba con la observada a nivel de mRNA. Conclusión: Los suplementos terapéuticos de rHuKGF mejoran la mala regulación de la vía de Akt en el trastorno del enfisema, dando lugar a una supervivencia celular alveolar a través de una activación de la vía de la supervivencia celular dependiente de VEGF endógena. Así pues, el rHuKGF podría ser un posible fármaco para el tratamiento del enfisema

Introduction: Emphysema has been associated with decreased VEGF andVEGFR-2 expression and the presence of high numbers of apoptotic alveolar cells. Keratinocyte growth factor stimulates VEGF synthesis which in turn confers normal lung structure maintenance via the Akt pathway. In this study the potential role of rHuKGF in the improvement of deregulated Akt mediated cell survival pathway in emphysematous mice was investigated Methods: Three experimental groups, i.e., emphysema, treatment and control groups, were prepared. Lungs of mice were treated on 3 occasions by oropharyngeal instillation of 10 mg rHuKGF per kg body weight after induction of emphysema with porcine pancreatic elastase. Subsequently, lung tissues from mice were collected for histopathology and molecular biology studies. Results and discussion: Histopathology photomicrographs and destructive index analysis have shown that elastase-induced airspace enlargement and loss of alveoli recovered in the treatment group. rHuKGF stimulates VEGF production which in turn induces the Akt mediated cell survival pathway in emphysematous lungs. mRNA expression of VEGF, VEGFR, PI3K and Akt was significantly increased while Pten, Caspase-9 and Bad was notably decreased in treatment group when compared with emphysema group, being comparable with the control group. Moreover, VEGF protein expression was in accordance with that found for mRNA. Conclusion: Therapeutic rHuKGF supplementation improves the deregulated Akt pathway in emphysema, resulting in alveolar cell survival through activation of the endogenous VEGF-dependent cell survival pathway. Hence rHuKGF may prove to be a potential drug in the treatment of emphysema

Recombinant Human Keratinocyte Growth Factor Induces Akt Mediated Cell Survival Progression in Emphysematous Mice.

INTRODUCTION: Emphysema has been associated with decreased VEGF and VEGFR-2 expression and the presence of high numbers of apoptotic alveolar cells. Keratinocyte growth factor stimulates VEGF synthesis which in turn confers normal lung structure maintenance via the Akt pathway. In this study the potential role of rHuKGF in the improvement of deregulated Akt mediated cell survival pathway in emphysematous mice was investigated. METHODS: Three experimental groups, i.e., emphysema, treatment and control groups, were prepared. Lungs of mice were treated on 3 occasions by oropharyngeal instillation of 10mg rHuKGF per kg body weight after induction of emphysema with porcine pancreatic elastase. Subsequently, lung tissues from mice were collected for histopathology and molecular biology studies. RESULTS AND DISCUSSION: Histopathology photomicrographs and destructive index analysis have shown that elastase-induced airspace enlargement and loss of alveoli recovered in the treatment group. rHuKGF stimulates VEGF production which in turn induces the Akt mediated cell survival pathway in emphysematous lungs. mRNA expression of VEGF, VEGFR, PI3K and Akt was significantly increased while Pten, Caspase-9 and Bad was notably decreased in treatment group when compared with emphysema group, being comparable with the control group. Moreover, VEGF protein expression was in accordance with that found for mRNA. CONCLUSION: Therapeutic rHuKGF supplementation improves the deregulated Akt pathway in emphysema, resulting in alveolar cell survival through activation of the endogenous VEGF-dependent cell survival pathway. Hence rHuKGF may prove to be a potential drug in the treatment of emphysema.

Therapeutic potential of growth factors in pulmonary emphysematous condition.

Pulmonary emphysema is a major manifestation of chronic obstructive pulmonary disease (COPD), which is characterized by progressive destruction of alveolar parenchyma with persistent inflammation of the small airways. Such destruction in the distal respiratory tract is irreversible and irreparable. All-trans-retinoic acid was suggested as a novel therapy for regeneration of lost alveoli in emphysema. However, profound discrepancies were evident between studies. At present, no effective therapeutic options are available that allow for the regeneration of lost alveoli in emphysematous human lungs. Recently, some reports on rodent's models have suggested the beneficial effects of various growth factors toward alveolar maintenance and repair processes.

Palifermin induces alveolar maintenance programs in emphysematous mice.

RATIONALE: Emphysema is characterized by destruction of alveoli with ensuing airspace enlargement and loss of alveoli. Induction of alveolar regeneration is still a major challenge in emphysema therapy. OBJECTIVES: To investigate whether therapeutic application of palifermin (DeltaN23-KGF) is able to induce a regenerative response in distal lung parenchyma after induction of pulmonary emphysema. METHODS: Mice were therapeutically treated at three occasions by oropharyngeal aspiration of 10 mg DeltaN23-KGF per kg body weight after induction of emphysema by porcine pancreatic elastase. MEASUREMENTS AND MAIN RESULTS: Airflow limitation associated with emphysema was largely reversed as assessed by noninvasive head-out body plethysmography. Porcine pancreatic elastase-induced airspace enlargement and loss of alveoli were partially reversed as assessed by design-based stereology. DeltaN23-KGF induced proliferation of epithelium, endothelium, and fibroblasts being associated with enhanced differentiation as well as increased expression of vascular endothelial growth factor, vascular endothelial growth factor receptors, transforming growth factor (TGF)-beta1, TGF-beta2, (phospho-) Smad2, plasminogen activator inhibitor-1, and elastin as assessed by quantitative reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. DeltaN23-KGF induced the expression of TGF-beta1 in and release of active TGF-beta1 from primary mouse alveolar epithelial type 2 (AE2) cells, murine AE2-like cells LA-4, and cocultures of LA-4 and murine lung fibroblasts (MLF), but not in MLF cultured alone. Recombinant TGF-beta1 but not DeltaN23-KGF induced elastin gene expression in MLF. Blockade of TGF-signaling by neutralizing antibody abolished these effects of DeltaN23-KGF in LA-4/MLF cocultures. CONCLUSIONS: Our data demonstrate that therapeutic application of DeltaN23-KGF has the potential to induce alveolar maintenance programs in emphysematous lungs and suggest that the regenerative effect on interstitial tissue is linked to AE2 cell-derived TGF-beta1.

Systematic comparison of RNA extraction techniques from frozen and fresh lung tissues: checkpoint towards gene expression studies.

BACKGROUND: The reliability of gene expression profiling-based technologies to detect transcriptional differences representative of the original samples is affected by the quality of the extracted RNA. It strictly depends upon the technique that has been employed. Hence, the present study aimed at systematically comparing silica-gel column (SGC) and guanidine isothiocyanate (GTC) techniques of RNA isolation to answer the question which technique is preferable when frozen, long-term stored or fresh lung tissues have to be evaluated for the downstream molecular analysis. METHODS: Frozen lungs (n = 3) were prepared by long-term storage (2.5 yrs) in -80 degrees C while fresh lungs (n = 3) were harvested and processed immediately. The purity and quantification of RNA was determined with a spectrophotometer whereas the total amounted copy numbers of target sequences were determined with iCycler detection system for assessment of RNA intactness (28S and 18S) and fragment sizes, i.e. short (GAPDH-3' UTR), medium (GAPDH), and long (PBGD) with 200 bp, 700 bp, and 1400 bp distance to the 3'ends of mRNA motif, respectively. RESULTS: Total yield of RNA was higher with GTC than SGC technique in frozen as well as fresh tissues while the purity of RNA remained comparable. The quantitative reverse transcriptase-polymerase chain reaction data revealed that higher mean copy numbers of 28S and a longer fragment (1400 bp) were obtained from RNA isolated with SGC than GTC technique using fresh as well as frozen tissues. Additionally, a high mean copy number of 18S and medium fragment (700 bp) were obtained in RNA isolated with SGC technique from fresh tissues, only. For the shorter fragment, no significant differences between both techniques were noticed. CONCLUSION: Our data demonstrated that although the GTC technique has yielded a higher amount of RNA, the SGC technique was much more superior with respect to the reliable generation of an intact RNA and effectively amplified longer products in fresh as well as in frozen tissues.