Lipidomic Analyses Reveal Specific Alterations of Phosphatidylcholine in Dystrophic Mdx Muscle

William J Valentine; Sherif A Mostafa; Suzumi M Tokuoka; Fumie Hamano; Natsuko F Inagaki; Joel Z Nordin; Norio Motohashi; Yoshihiro Kita; Yoshitsugu Aoki; Takao Shimizu; Hideo Shindou

doi:10.3389/fphys.2021.698166

Lipidomic Analyses Reveal Specific Alterations of Phosphatidylcholine in Dystrophic Mdx Muscle

Front Physiol. 2022 Jan 12:12:698166. doi: 10.3389/fphys.2021.698166. eCollection 2021.

Authors

William J Valentine^{1

2}, Sherif A Mostafa^{2

3}, Suzumi M Tokuoka⁴, Fumie Hamano^{2

5}, Natsuko F Inagaki², Joel Z Nordin^{1

6}, Norio Motohashi¹, Yoshihiro Kita⁵, Yoshitsugu Aoki¹, Takao Shimizu², Hideo Shindou^{2

7}

Affiliations

¹ Department of Molecular Therapy, National Center for Neurology and Psychiatry (NCNP), National Institute of Neuroscience, Kodaira, Tokyo, Japan.
² Department of Lipid Signaling, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Japan.
³ Weill Cornell Medicine-Qatar, Doha, Qatar.
⁴ Department of Lipidomics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan.
⁵ Life Sciences Core Facility, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan.
⁶ Department of Laboratory Medicine, Centre for Biomolecular and Cellular Medicine, Karolinska Institutet, Huddinge, Sweden.
⁷ Department of Medical Lipid Science, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan.

Abstract

In Duchenne muscular dystrophy (DMD), lack of dystrophin increases the permeability of myofiber plasma membranes to ions and larger macromolecules, disrupting calcium signaling and leading to progressive muscle wasting. Although the biological origin and meaning are unclear, alterations of phosphatidylcholine (PC) are reported in affected skeletal muscles of patients with DMD that may include higher levels of fatty acid (FA) 18:1 chains and lower levels of FA 18:2 chains, possibly reflected in relatively high levels of PC 34:1 (with 16:0_18:1 chain sets) and low levels of PC 34:2 (with 16:0_18:2 chain sets). Similar PC alterations have been reported to occur in the mdx mouse model of DMD. However, altered ratios of PC 34:1 to PC 34:2 have been variably reported, and we also observed that PC 34:2 levels were nearly equally elevated as PC 34:1 in the affected mdx muscles. We hypothesized that experimental factors that often varied between studies; including muscle types sampled, mouse ages, and mouse diets; may strongly impact the PC alterations detected in dystrophic muscle of mdx mice, especially the PC 34:1 to PC 34:2 ratios. In order to test our hypothesis, we performed comprehensive lipidomic analyses of PC and phosphatidylethanolamine (PE) in several muscles (extensor digitorum longus, gastrocnemius, and soleus) and determined the mdx-specific alterations. The alterations in PC 34:1 and PC 34:2 were closely monitored from the neonate period to the adult, and also in mice raised on several diets that varied in their fats. PC 34:1 was naturally high in neonate's muscle and decreased until age ∼3-weeks (disease onset age), and thereafter remained low in WT muscles but was higher in regenerated mdx muscles. Among the muscle types, soleus showed a distinctive phospholipid pattern with early and diminished mdx alterations. Diet was a major factor to impact PC 34:1/PC 34:2 ratios because mdx-specific alterations of PC 34:2 but not PC 34:1 were strictly dependent on diet. Our study identifies high PC 34:1 as a consistent biochemical feature of regenerated mdx-muscle and indicates nutritional approaches are also effective to modify the phospholipid compositions.

Keywords: Duchenne; mdx; muscular dystrophy; oleic acid; phosphatidylcholine; phospholipid; skeletal muscle.