Membrane-Perturbing Activities of KL4-Related Surfactant Peptides
KL4 is a 21-residue peptide proposed as a potential substitute of pulmonary surfactant protein SP-B in synthetic surfactants, intended for the treatment of respiratory pathologies. The peptide, composed by leucines interrupted by lysine every four residues, was synthesized to simulate C-terminal amphipathic helical segments of SP-B. Once incorporated into lipid-protein complexes, KL4 promotes formation of interfacial films that produce and maintain surface tensions below 5 mN/m during compression-expansion cycling. Although KL4 was designed as an amphipathic helix at the membrane surface, the data on orientation and interactions of the peptide in membranes are contradictory. In the present …
c-Fos induces chondrogenic tumor formation in immortalized human mesenchymal progenitor cells
Mesenchymal progenitor cells (MPCs) have been hypothesized as cells of origin for sarcomas, and c-Fos transcription factor has been showed to act as an oncogene in bone tumors. In this study, we show c-Fos is present in most sarcomas with chondral phenotype, while multiple other genes are related to c-Fos expression pattern. To further define the role of c-Fos in sarcomagenesis, we expressed it in primary human MPCs (hMPCs), immortalized hMPCs and transformed murine MPCs (mMPCs). In immortalized hMPCs, c-Fos expression generated morphological changes, reduced mobility capacity and impaired adipogenic- and osteogenic-differentiation potentials. Remarkably, immortalized hMPCs or mMPCs express…