Cellular origin of microfibrils explored by monensin-induced perturbation of secretory activity in embryonic primary cultures

Abstract

Fibrillin is a primary component of elastin-associated microfibrils. Since microfibrils are distributed rather ubiquitously in embryonic tissues, attention has focused on the types of cells responsible for producing fibrillin. To clarify this issue, we employed monensin-induced perturbation of secretory activity in embryonic primary cultures, as this would allow examination of both the secreted protein and the formation of extracellular fibrils in the same culture. Micromasses of avian limb bud mesoderm, its ectodermal covering and several explants from other sources were cultured in the presence and absence of monensin, and evaluated immunohistochemically using antibodies against fibrillin and cell lineage markers. The results indicated that monensin perturbation induced intracellular accumulation of fibrillin and prevented the formation of microfibrils. It was shown specifically that not only mesodermally derived fibrogenic cells and myogenic cells of skeletal and smooth muscle cell lineage, but also epithelial-type cells such as endothelial and ectodermal cells, are producers of fibrillin. This dual cellular origin of fibrillin at the ectomesenchymal interface is considered significant for understanding the formation and remodeling of microfibrils originating from the basal lamina.

Progressive Bundling of Fibrillin Microfibrils into Oxytalan Fibers in the Chick Presumptive Dermis

“…It is therefore considered that de novo assembly of microfibrils was active in the periphery of and/or deep within the preexisting bundles in the early stages, or ED4‐6. This explanation is consistent with our previous finding that mesenchymal cells prepared from limb bud mesoderm at early stages of development are the potent producer of fibrillin and form a microfibrillar network in vitro (Yamazaki et al, 2007b).…”

Synergistic effect of exogeneous and endogeneous electrostimulation on osteogenic differentiation of human mesenchymal stem cells seeded on silk scaffolds

“…Also, COLL1A1 expression decreased in the silk+mon samples at day 28. Monensin induces intracellular accumulation of secreted components and also results in a lack of extracellular fiber formation by blocking protein transport through the Golgi aparatus . Low collagen expression levels may be related to inhibition of protein transport by monensin in the silk+mon samples.…”

“…Monensin induces intracellular accumulation of secreted components and also results in a lack of extracellular fiber formation by blocking protein transport through the Golgi aparatus. 46 Low collagen expression levels may be related to inhibition of protein transport by monensin in the silkþmon samples. However, electrical fields eliminated the negative effect of monensin on BSP, OPN, and COLL1A1 expressions and resulted in the significant upregulation of these genes compared to the silkþmon group.…”

Development of the Tarsometatarsal Skeleton by the Lateral Fusion of Three Cylindrical Periosteal Bones in the Chick Embryo (Gallus gallus)

“…Briefly, sections equilibrated and blocked in 1% bovine serum albumin (BSA)-PBS for 1 hr were reacted with mouse anti-chick fibrillin-2 IgG (undiluted hybridoma conditioned medium of FB1; Isokawa et al, 2004;Yamazaki et al, 2007b) for 1 hr and washed in PBS. Sections were subsequently incubated in fluorescein-isothiocyanate-conjugated goat anti-mouse IgG for 1 hr.…”