Bone Marrow Origin of Cells with Capacity for Homing and Differentiation to Esophageal Squamous Epithelium

Abstract

Our goal was to determine whether esophageal progenitor cells could be isolated from adult mouse esophagus or bone marrow and shown to home to and proliferate in the irradiated esophagus of recipient mice. Esophageal progenitor cells were isolated from adult male C3H/HeNsd or C57BL/6J green fluorescent protein (GFP(+)) mice by a serial in vitro preplate technique or the technique of side population cell sorting. When injected intravenously (i.v.), these cells homed to the 30-Gy-irradiated esophagus of GFP(-) female recipient mice and formed donor-origin esophageal foci. GFP(+) whole murine bone marrow cells injected i.v. also formed donor-origin esophageal squamous cell foci and protected recipient GFP(-) mice from upper-body irradiation in a cell dose-dependent manner. Marrow chimeric GFP(-) mice reconstituted with GFP(+) cells showed migration of GFP(+) marrow cells to the esophagus after 30 Gy irradiation. Purified esophageal progenitor cells isolated from first-generation preplate cell recipients engrafted after i.v. injection to the esophagus of second-generation-irradiated recipient mice. These data establish that esophageal progenitor cells can home to the irradiated esophagus and show limited differentiation capacity to squamous epithelium.

Gene therapy approaches for stem cell protection

“…Expression of the MnSOD transgene by plasmid liposome transfection of the recipient has been shown to enhance capacity to reconstitute the irradiated esophagus and other tissues with donor bone marrow origin cells. 12,15 In these experiments, MnSOD-plasmid liposomes (PL)-mediated transgene expression in the recipient microenvironment also increased surviving recipient stem cell repopulation capacity. 13,15 Whether overexpression of an antioxidant transgene in hematopoietic stem cells protects self-renewal capacity is not yet known.…”

“…8,9 Antioxidant approaches toward enhancing stem cell protection include transfection of the transgenes for manganese superoxide dismutase (MnSOD), catalase, glutathione, peroxidase, metallothione and others. 10,11 While there is some protective effect of antioxidant transgene expression shown with respect to clonogenic survival of cells in culture, 12,13 no assays of stem cell competitive repopulation capacity have been reported. In contrast, when the microenvironment is induced to overexpress antioxidants by gene therapy, the homing capacity for engrafting stem cells, and also survival of residual stem cells, is enhanced.…”

“…In contrast, when the microenvironment is induced to overexpress antioxidants by gene therapy, the homing capacity for engrafting stem cells, and also survival of residual stem cells, is enhanced. 12 Gene therapy approaches toward directly protecting stem cells represent an attractive strategy; 10,11,14 however, there is also evidence that gene therapy-mediated protection of the microenvironment may also be of value. Expression of the MnSOD transgene by plasmid liposome transfection of the recipient has been shown to enhance capacity to reconstitute the irradiated esophagus and other tissues with donor bone marrow origin cells.…”

“…These two phenomena occur in non-hematopoietic as well as hematopoietic organs. 12,[24][25][26] Toxicity to the non-hematopoietic organ microenvironment can facilitate engraftment or repopulation by cells from other organs including the marrow. 24,27,28 Exposure of the rat liver to carbon tetrachloride, followed by further damage to repopulating cells by 3-amino-fluorine alters the liver microenvironment to accept bone marrow-derived cells which are capable of differentiating into both hepatocytes and hepatic duct cells.…”

“…11 In the irradiated esophagus, treatment with MnSOD-PL enhances homing of bone marrow-derived progenitors of esophageal squamous epithelium and repopulation of the damaged esophagus. 12 In the lung, MnSOD-PL administration decreases both early and late free radical production and both episodes of inflammatory cytokine release. Decrease in the late effect reduces bone marrow stromal cell migration to the lungs and decreases pulmonary fibrosis.…”