Identification of satellite cells from anole lizard skeletal muscle and demonstration of expanded musculoskeletal potential

Abstract

The lizards are evolutionarily the closest vertebrates to humans that demonstrate the ability to regenerate entire appendages containing cartilage, muscle, skin, and nervous tissue. We previously isolated PAX7-positive cells from muscle of the green anole lizard, Anolis carolinensis, that can differentiate into multinucleated myotubes and express the muscle structural protein, myosin heavy chain. Studying gene expression in these satellite/progenitor cell populations from A. carolinensis can provide insight into the mechanisms regulating tissue regeneration. We generated a transcriptome from proliferating lizard myoprogenitor cells and compared them to transcriptomes from the mouse and human tissues from the ENCODE project using XGSA, a statistical method for cross-species gene set analysis. These analyses determined that the lizard progenitor cell transcriptome was most similar to mammalian satellite cells. Further examination of specific GO categories of genes demonstrated that among genes with the highest level of expression in lizard satellite cells were an increased number of genetic regulators of chondrogenesis, as compared to mouse satellite cells. In micromass culture, lizard PAX7-positive cells formed Alcian blue and collagen 2a1 positive nodules, without the addition of exogenous morphogens, unlike their mouse counterparts. Subsequent quantitative RT-PCR confirmed up-regulation of expression of chondrogenic regulatory genes in lizard cells, including bmp2, sox9, runx2, and cartilage specific structural genes, aggrecan and collagen 2a1. Taken together, these data suggest that tail regeneration in lizards involves significant alterations in gene regulation with expanded musculoskeletal potency.

Growth factors improve the proliferation of Jeju black pig muscle cells by regulating MyoD and growth-related genes

“…ACAN is also a cartilage speci c matrix protein. Along with COL2A1, its upregulation can help pax7 positive satellite cells differentiate along the musculoskeletal lineage to form skeletal muscle [30]. However, in our results, cell proliferation rate of cells added with growth factor was high, although expression levels of these two genes in the presence of growth factors were lower than those in the control without the addition of a growth factor.…”

C3: An R package for cross-species compendium-based cell-type identification

“…Recently we have used this approach to identify that a novel PAX7+ cell population in lizard Anole carolinensis is highly similar to muscle satellite cells in human and mouse [15]. As another real-life application, we have recently used the C3 approach to demonstrate that a ROR1+ cell population derived from human pluripotent stem cells is similar to lens epithelial cells in both human and mouse [16].…”

Appendage Regeneration in Vertebrates: What Makes This Possible?

“…Following injury, these cells can activate, as demonstrated by the immune detection of telomerase and c-myc, and migrate to contribute to the blastema [ 91 , 92 ]. Transcriptomic and histological works on Anolis carolinensis tail regeneration led to the identification of a population of PAX7+ satellite cells, pointing to a stem-cell mediated process [ 20 , 93 ].…”

“…Differences are also seen when comparing blastemas of Anolis lizards and leopard gecko Eublepharis macularius. In the Anolis lizard, no cell proliferation was detectable leading some authors to question whether this was a real blastema [ 20 , 78 , 93 ], whereas the leopard gecko blastema was reported to be rich in actively proliferating cells [ 72 , 98 , 99 ]. A recent study by Lozito and Tuan suggests that Anolis tail regeneration could require cell populations of different origin.…”