MicroRNA induction blocks oil-gland formation in developing mouse skin
Increasing a family of small regulatory molecules prevented oil glands from forming in developing mouse skin, while hair follicles still formed. A single peer-reviewed study traced the effect to gene-regulating signals and changes in cell-cycle progression. The experiments describe the different identities acquired by neighbouring skin cells; they concern development in mice, with abnormalities also appearing in more mature hair follicles.
Science··Evening
Oil-gland cells fail to acquire their identity
Oil glands normally develop beside hair follicles, although the neighbouring cells take on different jobs. In experiments on developing mice, increasing microRNA-200 in the upper follicle prevented the oil-gland lineage from forming. MicroRNAs are small molecules involved in controlling gene expression. The single peer-reviewed study examined the placement of these molecules within skin, finding abundant microRNA-200 expression in the hair matrix but an absence where gland stem cells normally emerge.[1]
Gene signals and the cell cycle change together
The molecular findings linked microRNA-200 to lower SOX9, a protein regulating genes involved in fat metabolism. The researchers identified targets that restrain WNT, a cellular signalling pathway; repression of those targets accompanied increased WNT activity. Measurements of individual cells and their positions placed the signalling changes within the follicle. Progression between the G1 and S stages of the cell cycle was also restricted, connecting cell identity with the machinery governing multiplication.[1]
Hair forms with later structural abnormalities
After birth, gland progenitors and differentiating cells were markedly less abundant in the induced animals than in controls. Hair still formed, but later follicles showed twisting and altered orientation. Uneven survival after birth restricted the developmental period available for study. These mouse experiments investigated the formation of skin structures; safety and effectiveness of a comparable intervention in adult human skin remain unestablished.[1]
