Bone Marrow Stem Cells Expressing Keratinocyte Growth Factor via an Inducible Lentivirus Protects against Bleomycin-Induced Pulmonary Fibrosis

Abstract

Many common diseases of the gas exchange surface of the lung have no specific treatment but cause serious morbidity and mortality. Idiopathic Pulmonary Fibrosis (IPF) is characterized by alveolar epithelial cell injury, interstitial inflammation, fibroblast proliferation and collagen accumulation within the lung parenchyma. Keratinocyte Growth Factor (KGF, also known as FGF-7) is a critical mediator of pulmonary epithelial repair through stimulation of epithelial cell proliferation. During repair, the lung not only uses resident cells after injury but also recruits circulating bone marrow-derived cells (BMDC). Several groups have used Mesenchymal Stromal Cells (MSCs) as therapeutic vectors, but little is known about the potential of Hematopoietic Stem cells (HSCs). Using an inducible lentiviral vector (Tet-On) expressing KGF, we were able to efficiently transduce both MSCs and HSCs, and demonstrated that KGF expression is induced in a regulated manner both in vitro and in vivo. We used the in vivo bleomycin-induced lung fibrosis model to assess the potential therapeutic effect of MSCs and HSCs. While both populations reduced the collagen accumulation associated with bleomycin-induced lung fibrosis, only transplantation of transduced HSCs greatly attenuated the histological damage. Using double immunohistochemistry, we show that the reduced lung damage likely occurs through endogenous type II pneumocyte proliferation induced by KGF. Taken together, our data indicates that bone marrow transplantation of lentivirus-transduced HSCs can attenuate lung damage, and shows for the first time the potential of using an inducible Tet-On system for cell based gene therapy in the lung.

Bone marrow-derived mononuclear cell therapy attenuates silica-induced lung fibrosis

“…These studies used mesenchymal stem cells (MSC) which require cell-culture processes, yielding some disadvantages related to culture conditions that are detrimental for cell transplantation and the risk of contamination and immunological reactions [27]. Recently, haematopoietic stem cells have been recognised as progenitors for several cell types (endothelial, epithelial, myocytes and neurons) and have been able to reduce lung injury in murine model of fibrosis [28]. Therefore, in our study bone marrow mononuclear cells, which are known to contain both haematopoietic and MSC, were chosen to treat silica-induced lung fibrosis.…”

Spatiotemporal quantification of cell dynamics in the lung following influenza virus infection

“…Based on the sickness scores of inflammation, edema, or fibrosis, a semi-quantitative grading system has been used to classify different levels of lung damage. [7][8][9][10][11][12][13][14] The average size of the alveolar sac has been used to quantify hyperoxia-induced lung injury, where alveolar networks are destroyed. 15,16 The tissue thickness has been measured from hematoxylin and eosin (H&E) stained images to quantify bleomycin-induced lung injury leading to fibrosis.…”

Rescue of murine silica-induced lung injury and fibrosis by human embryonic stem cells

“…Intratracheal instillation of palifermin (DN23-KGF), a recombinant keratinocyte growth factor (KGF), has been shown to be capable of stimulating emphysematous lung regeneration in experimental animals, probably through enhanced production of cytokines such as vascular endothelial growth factor and TGF-b [30]. Interestingly, transplantation of lentivirus-transduced bone marrow haemopoietic stem cells expressing KGF has been shown to attenuate lung damage in a bleomycin murine model of pulmonary fibrosis [31], possibly via complex paracrine interaction. Another epithelial cell growth factor, hepatocyte growth factor (HGF), has also been successfully used to treat bleomycin-induced pulmonary fibrosis by toracothomic lung administration of an HGF plasmid (pCikhHGF) using electroporation [32].…”