Targeted cell replacement with bone marrow cells for airway epithelial regeneration

Abstract

It has been suggested that some adult bone marrow cells (BMC) can localize to the lung and develop tissue-specific characteristics including those of pulmonary epithelial cells. Here, we show that the combination of mild airway injury (naphthalene-induced) as a conditioning regimen to direct the site of BMC localization and transtracheal delivery of short-term cultured BMC enhances airway localization and adoption of an epithelial-like phenotype. Confocal analysis of airway and alveolar-localized BMC (fluorescently labeled) with epithelial markers shows expression of the pulmonary epithelial proteins, Clara cell secretory protein, and surfactant protein C. To confirm epithelial gene expression by BMC, we generated transgenic mice expressing green fluorescent protein (GFP) driven by the epithelial-specific cytokeratin-18 promoter and injected BMC from these mice transtracheally into wild-type recipients after naphthalene-induced airway injury. BMC retention in the lung was observed for at least 120 days following cell delivery with increasing GFP transgene expression over time. Some BMC cultured in vitro over time also expressed GFP transgene, suggesting epithelial transdifferentiation of the BMC. The results indicate that targeted delivery of BMC can promote airway regeneration.

Identification of a bone marrow–derived epithelial-like population capable of repopulating injured mouse airway epithelium

“…Bone marrow-derived cells have been suggested to give rise to lung epithelial cells in vitro (7,35) and in vivo (2,5,13). However, the precise fate of specific BMCs has not been well characterized to date.…”

“…Mouse whole bone marrow was harvested and cultured as previously described (13). Cells were cultured in DMEM (Invitrogen) supplemented with 10% FBS (Invitrogen) and 1% penicillin-streptomycin (Invitrogen).…”

“…To explore whether endogenous Ccsp + BMCs may be involved in lung repair, we assessed Ccsp + cells in the bone marrow and peripheral blood after naphthalene-induced lung injury. In contrast to the lung, where naphthalene depletes Ccsp + cells (13,14), the number of Ccsp + cells in marrow and peripheral blood increased as early as 2 hours after naphthalene injury and peaked at 2 days after injury ( Figure 5A). The number of Ccsp + cells remained elevated for 4 days and returned to near baseline by 20 days.…”

“…To determine whether the Ccsp + BMCs are more efficiently retained in the lung, sorted Ccsp + and Ccsp -cells labeled with the commercial red fluorescent marker 5-(and-6)-([(4-chloromethyl)benzoyl]amino) tetramethylrhodamine (CMTMR) were injected transtracheally or intravenously into naphthalene-injured recipients as previously described (13). Four days later, the lungs were harvested.…”

Mesenchymal stem cells: mechanisms of potential therapeutic benefit in ARDS and sepsis

“…[19][20][21] However, with refi ned research techniques, MSC engraftment seems to be a rare event 22,23 of unclear physiological signifi cance. 13,24 A growing number of studies have shown that MSCs have immunomodulatory and anti-infl ammatory eff ects despite minimum or absent engraftment.…”