AsianScientist (Mar. 27, 2024) – A recent study has discovered a process that can transform skin cells into limb cells, potentially leading to advancements in regenerative therapy.
Through a joint effort, scientists from Kyushu University in Fukuoka, Japan, and Harvard Medical School, Boston, have identified proteins that can convert fibroblasts, or skin cells, into cells resembling those found in developing limbs. This breakthrough offers the possibility of utilizing these modified cells in regenerative treatments to repair or replace damaged or lost tissues in limbs.
The study, detailed in the Developmental Cell journal, signifies a significant step forward in understanding limb development and changing the landscape of treatment for millions affected by limb loss worldwide. Approximately 60 million individuals globally suffer from limb loss due to various medical conditions or traumatic incidents. Those with limb injuries often resort to artificial materials and metal prostheses, yet restoring natural limb functions remains a challenge despite technological progress. The study introduces a potential treatment by reprogramming fibroblast cells into limb progenitor cells, mirroring the natural process of limb development.
Dr. Yuji Atsuta, the lead researcher of the collaboration, aims to establish an accessible method for generating these vital cells.
“During limb development in the embryo, limb progenitor cells in the limb bud give rise to most of the different limb tissues, such as bone, muscle, cartilage, and tendon. It’s therefore important to establish an easy and accessible way of making these cells,” explains Atsuta, who initiated this project at Harvard Medical School and continues it as a lecturer at Kyushu University’s Graduate School of Sciences.
The groundbreaking discovery
Currently, a common method to obtain limb progenitor cells is directly from embryos, which raises ethical concerns when involving human embryos. An alternative approach includes creating these cells from induced pluripotent stem cells, which are adult cells transformed into a state resembling embryonic cells. Subsequently, these reprogrammed cells can be guided to develop into specific types of tissues. However, induced pluripotent stem cells pose a cancer risk. Therefore, Atsuta’s team devised a technique that skips induced pluripotent stem cells by directly converting fibroblast cells into limb progenitors. This breakthrough simplifies the process and reduces the cancer risks associated with induced pluripotent stem cells.
The research team initially examined gene expression in early limb buds, identifying 18 crucial genes, predominantly transcription factors. Transcription factors regulate gene expression in cells. Introducing these genes into mouse embryo fibroblasts prompted the cells to acquire limb progenitor characteristics.
Through a series of experiments, the team pinpointed three proteins—Prdm16, Zbtb16, and Lin28a—that are essential for fibroblast reprogramming. A fourth protein, Lin41, facilitated the cultured limb progenitor cells to grow and multiply more rapidly.
“These reprogrammed cells not only mimic molecularly; we have verified their potential to develop into specialized limb tissues,” says Atsuta.
Atsuta’s lab group is currently exploring the application of this method to human cells for future therapeutic uses, as well as to snakes, whose ancestors had limbs that were lost during evolution.
“The reprogrammed limb progenitor cells produced limb bud-like organoids, suggesting the feasibility of generating limb tissues in species that no longer possess them. The study of limbless snakes can unveil new pathways and insights in developmental biology,” states Atsuta.
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Source: Kyushu University ; Image: D. Burnette, J. Lippincott-Schwartz/NICHD
You can access the article at: Direct reprogramming of non-limb fibroblasts to cells with properties of limb progenitors
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