Wu et al. · bioRxiv (preprint) · 2024
MAPK13 controls structural remodeling and disease after epithelial injury
Wu Kangyun, Zhang Yong, Mao Dailing, Iberg Courtney A., Yin-Declue Huiqing, Sun Kelly, Keeler Shamus P., Wikfors Hallie A., Young Deanna, Yantis Jennifer, Austin Stephen R., Byers Derek E, Brody Steven L., Crouch Erika C., Romero Arthur G., Holtzman Michael J.
The study
What was asked, and what was found
Wu et al., bioRxiv (preprint), 2024 asked why repair after an epithelial injury sometimes turns into permanent structural remodelling, and whether one stress kinase governs the turn. Working in a mouse model where Sendai virus infection is followed by long-term lung disease, the authors made a Mapk13 knockout. Those mice showed a similar acute illness to wild-type mice, tracked by weight loss and lung levels of viral RNA, but the later remodelling largely did not happen: less basal epithelial stem cell hyperplasia, less immune activation, less mucus, better blood oxygen saturation and a blunted airway response to inhaled methacholine.
The human half of the study is where the AUM product was used. Lung sections from people with asthma and chronic obstructive pulmonary disease showed MAPK13 strongly raised in KRT5 positive airway basal cells against non-disease controls, so the authors moved to primary human tracheobronchial epithelial cells to ask whether MAPK13 is needed for those cells to grow. The cells were held in submerged culture, which keeps the basal stem cell pool growing rather than differentiating, and seeded at 2 by 10 to the fourth cells per well in 96-well plates.
Two distinct AUMsilence sdASOs against MAPK13 were added straight to the medium at 1 μM on culture days 1 and 3, with a scrambled control from the same supplier, and read out on day 5. Both lowered MAPK13 protein on immunoblot and both cut cell number against the scrambled control. The paper reports the direction and not a percentage, and states that the figure shows one donor representative of three. The experiment is a two-sequence knockdown with a matched scramble in a primary human cell type, and it was run with no transfection reagent named anywhere in the method.
Key findings
- Two separate AUMsilence sdASOs against MAPK13, each given at 1 μM to primary human tracheobronchial epithelial cells in submerged culture, lowered MAPK13 protein and slowed the growth of the basal epithelial stem cells beside a scrambled control.(Results, MAPK13 gene knockdown attenuates basal-ESC growth in a human model, Fig. 6B to 6E)
- The knockdown was done in cells kept deliberately in submerged culture rather than at an air-liquid interface, so what was measured was growth of the basal stem cell pool itself rather than differentiation.(Results, MAPK13 gene knockdown attenuates basal-ESC growth in a human model)
- MAPK13 was strongly raised in airway basal cells in asthma and chronic obstructive pulmonary disease lung tissue compared with non-disease controls, which is what made it worth knocking down in the human cells.(Results, MAPK13 gene knockdown attenuates basal-ESC growth in a human model, Fig. 6A)
- The knockout animals were not protected from the infection itself: weight loss and lung viral RNA were similar to wild-type, which is what makes the later difference a remodelling effect rather than a milder infection.(Results, Mapk13 gene knockout prevents PVLD in a mouse model, Fig. 1A and 1B)
- In the separate mouse arm, which used a CRISPR gene knockout rather than any oligonucleotide, losing Mapk13 left the acute viral illness unchanged but blocked the later remodelling: less basal cell hyperplasia, less immune activation and less mucinous differentiation.(Abstract)
- The same mouse knockout improved two functional readouts, blood oxygen saturation and the airway response to inhaled methacholine.(Results, Mapk13 gene knockout prevents PVLD in a mouse model, Fig. 5A and 5B)
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