ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Christian Hoegsbjerg is first author on ‘ Fibre type differences in the organisation of mononuclear cells and myonuclei at the tips of human myofibres’, published in JCS. Christian is a PhD student in the lab of Professor Abigail Mackey at the Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark, investigating the form, function and regeneration of the myotendinous junction.
Christian Hoegsbjerg
How would you explain the main findings of your paper in lay terms?
Human tendons are subjected to more force than most realise, with some tendons subjected to forces many times greater than bodyweight. As such, it is not surprising that muscles are adapted to grip tightly onto tendons with their ‘fingers’. However, it is also this grip that is lost during sports injuries such as muscle strains. For this reason, we wanted to investigate this critical junction at the level of individual muscle cells. Our findings are quite counterintuitive: we observe many smaller cells tugged ‘in between the fingers’ of the muscle fibres. This suggests that this junction is more dynamic, and that repairing the junction is more important than maximizing the ‘grip strength’ of the muscle. Additionally, our results suggest that the grip between the tendon and slow, fatigue-resistant muscle fibres requires more maintenance than that between the tendon and fast, fatigable muscle fibres.
Were there any specific challenges associated with this project? If so, how did you overcome them?
The myotendinous junction (MTJ) is a challenging structure to analyse, particularly when attempting to quantify it. This is why we employed a 3D approach, as comparable 2D sections of the MTJ are difficult to obtain reliably. This, in turn, complicated the analysis further. However, by seeking help from image analysis specialists and programmers, we were able to overcome this challenge. This highlights the importance of collaboration within science, particularly across disciplines.
Why did you choose Journal of Cell Science for your paper?
I was a co-author on an earlier paper published in Journal of Cell Science that explored the gene expression of the MTJ using single-nucleus RNA sequencing. The work I did in this paper builds on those results, so it was a natural choice to publish in the same journal.
A 2D maximum-intensity projection of a 3D image of a single muscle cell at the MTJ. The muscle cell membrane is defined by dystrophin. Note the very high accumulation of cells and nuclei in the folded region of the junction (defined by collagen XXII), which is counterintuitive to the notion of optimisation for force transmission. Scale bar: 50 µm.
A 2D maximum-intensity projection of a 3D image of a single muscle cell at the MTJ. The muscle cell membrane is defined by dystrophin. Note the very high accumulation of cells and nuclei in the folded region of the junction (defined by collagen XXII), which is counterintuitive to the notion of optimisation for force transmission. Scale bar: 50 µm.
Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?
I would like to give credit to my current principal PhD supervisor, Abigail Mackey. She first took me in as a master’s student and has invested a lot of effort not only in my projects but also in my personal development. In particular, she has instilled in me the value of simple and concise communication. When I left university, I was prone to using overly complicated formulations to sound more ‘sciency’, but I have since learned that ‘fancier’ language does not equal better when it comes to communicating science.
Who are your role models in science? Why?
I would have to choose one of the ancient Greek philosophers, like Thales of Miletus (∼600–500 BCE) and his successors. Arguably the first known scientist, Thales sought to uncover patterns in nature to explain how the world works, supplanting widely held superstitious beliefs with science. I deeply admire how he and others refused to be constrained by the belief systems of their peers, laying the way for modern science.
What's next for you?
Naturally, the remainder of my PhD is a key focus (I am currently a first year PhD student). I am particularly looking forward to my upcoming exchange stay in the USA, where I plan to continue my research on the structure and repair of the MTJ using in vivo two-photon imaging.
Tell us something interesting about yourself that wouldn't be on your CV
Besides biology and exercise, my personal obsessions are history and geopolitics, as I believe there is much to learn from the past. With modern technological advancements, it is easy to dismiss the achievements of our predecessors as ‘primitive’, both in science and in society. However, if we fail to see through our ‘modern hubris’, we risk repeating the mistakes of the past.
Christian Hoegsbjerg’s contact details: Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Building 8, Nielsine Nielsens vej 11, 2400 Copenhagen, Denmark.
E-mail: [email protected]
