Fibroadipogenic progenitor-derived Gdf10 regulates neuromuscular junction and fat content in tongue muscles

Abstract

Obstructive sleep apnea (OSA) is the most prevalent sleep disorder globally 4.5% in men and 2.5% in women. OSA increases the risk of more severe diseases such as heart attack, high blood pressure, type 2 diabetes, obesity, mild cognitive impairment, and depression. The known craniofacial anatomical changes leading to OSA are relaxed muscles and/or enlarged soft tissues by fat infiltration in the soft palate, pharynx, and particularly tongue, which blocks the upper airway during sleep. Although obesity is one of the main causes to induce OSA, the underlying mechanism of those changes has not been researched. The objective of our study is to understand the mechanism leading to those craniofacial changes that generate foundations to develop potential therapeutics for OSA. We hypothesize that high-fat diet-induced obesity regulates the fibroadipogenic progenitors, which are critical for neuromuscular interaction and is mainly responsible for increased fat content in skeletal muscles. To test this hypothesis, we used a mouse model fed with a high-fat diet to induce obesity or a normal diet (control group) for 6 months. Then we isolated tongue muscles for histology analysis, such as muscle size, neuromuscular junction integrity, and adipocyte content.We found that a high-fat diet leaded adipocyte hypertrophy and reduced intact neuromuscular junction in tongue muscles. To investigate the role of fibroadipogenic progenitors for tongue phenotypes by a high-fat diet, we isolated fibroadipogenic progenitor cells to measure transcript levels of Gdf10, also known as Bmp3b, since fibroadipogenic progenitor-derived Gdf10 has been known to stabilize Schwann cells for neuromuscular integrity in muscles. The role of Gdf10 has been suggested to protect from obesity by limiting adipocyte hypertrophy. Using single-cell RNA sequencing analysis, Gdf10 is specifically expressed in fibroadipogenic progenitors but not adipocyte or Schwann cells. We found that Gdf10 transcript levels are significantly reduced by a high-fat diet in tongue fibroadipose progenitors. Taken together, the reduced Gdf10 of fibroadipogenic progenitors by a high-fat diet reduces neuromuscular integrity but induces fat infiltration in tongue muscles in a paracrine manner. Therefore, targeting to increase Gdf10 expression is a potential therapeutic to reduce OSA by maintaining healthy tongue muscle. NIH R01AR071397 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.