Medical Research Council - London Institute of Medical Sciences

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Past Tense

How muscle cells derived from stem cells align and organise

09 April 2022

Past Tense

No strangers to tension, our muscles drag our bodies around, flexing their inner bundles of myofibres, each of which is a long chain of tiny stretchy sarcomeres. But how these neat, organised structures emerge during development is still a little mysterious. Here scientists grow myofibres from human induced pluripotent stem cells. Artificial colours highlight fibres pointing in similar directions – they look a little chaotic to begin with (bottom left), but over the next two weeks (left to right, bottom row followed by top row) they self-organise, grouping into similar bundles. Researchers find that even at this early stage, myofibres are getting tense – using mechanical forces as 'signals' to co-ordinate with their neighbours. Zapping tiny parts of this early muscle with laser light causes the structures to twang apart – raising questions about how much tension is involved in assembling the early musculoskeletal system.

Written by John Ankers

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