March 12th, 2025
Investigators funded in part by NIAMS have identified a novel type of cartilage cell that may have implications for regenerative medicine and could inform future therapeutic treatments for arthritis and other cartilage diseases. The team of investigators, led by Maksim Plikus, Ph.D., and Raul Ramos, Ph.D., from the University of California, Irvine, published the study in Science.
Cartilage is a strong and flexible connective tissue made up of cells called chondrocytes. It provides cushioning and support in the joints, nose, ears, and other parts of the body. The investigators discovered that cartilage found in the head and neck of mice and humans stems from a novel type of cell they call "lipochondrocytes."
At the time of the discovery, the researchers were studying skin adipocytes, which are large, balloon-like cells that store and release energy. Adipocytes contain a “storage bubble” of fat, known as a lipid vacuole, which are flexible and can shrink or expand in response to food availability.
During his dissections of mouse ear skin, Ramos observed something unexpected. “It looked like an adipose cell, but at its heart, it was a cartilage cell,” he said. It looked different from other types of cartilage cells, though. The cell was very large and contained a lipid vacuole, leading Ramos and his colleagues to call them lipochondrocytes. They located the same type of cells in the ear, nose, and throat of laboratory mice and humans.
Further analysis revealed that – unlike adipocytes that shrink and expand based on the body’s energy needs – lipochondrocytes are stable and never change in size. Moreover, when they removed the lipid vacuole from the cell, the lipocartilage became stiffer and less pliable and soft, confirming their suspicions that the lipid vacuole was important to the cell’s structure.
“In essence, we identified a novel type of cartilage – a lipid-filled skeletal tissue we called 'lipocartilage,' that’s well-suited for forming squishy yet springy body parts, like ear lobes or nose tips,” said Plikus. He describes lipocartilage as a type of “bubble wrap.”
Plikus hopes that one day researchers may be able to use these insights to generate cartilages from lipochondrocytes that could potentially treat arthritis and other cartilage disorders, facial birth defects, and traumatic injuries to the nose and ears.
In addition to NIAMS, support for the research was provided by the W. M. Keck Foundation, the LEO Foundation, the Chan Zuckerberg Initiative, Horizon Europe, the National Science Foundation, the Simons Foundation, and the UC Irvine Beall Applied Innovation.
Ramos R, Pham KT, Prince RC, et al. Superstable lipid vacuoles endow cartilage with its shape and biomechanics. back...
Cartilage is a strong and flexible connective tissue made up of cells called chondrocytes. It provides cushioning and support in the joints, nose, ears, and other parts of the body. The investigators discovered that cartilage found in the head and neck of mice and humans stems from a novel type of cell they call "lipochondrocytes."
At the time of the discovery, the researchers were studying skin adipocytes, which are large, balloon-like cells that store and release energy. Adipocytes contain a “storage bubble” of fat, known as a lipid vacuole, which are flexible and can shrink or expand in response to food availability.
During his dissections of mouse ear skin, Ramos observed something unexpected. “It looked like an adipose cell, but at its heart, it was a cartilage cell,” he said. It looked different from other types of cartilage cells, though. The cell was very large and contained a lipid vacuole, leading Ramos and his colleagues to call them lipochondrocytes. They located the same type of cells in the ear, nose, and throat of laboratory mice and humans.
Further analysis revealed that – unlike adipocytes that shrink and expand based on the body’s energy needs – lipochondrocytes are stable and never change in size. Moreover, when they removed the lipid vacuole from the cell, the lipocartilage became stiffer and less pliable and soft, confirming their suspicions that the lipid vacuole was important to the cell’s structure.
“In essence, we identified a novel type of cartilage – a lipid-filled skeletal tissue we called 'lipocartilage,' that’s well-suited for forming squishy yet springy body parts, like ear lobes or nose tips,” said Plikus. He describes lipocartilage as a type of “bubble wrap.”
Plikus hopes that one day researchers may be able to use these insights to generate cartilages from lipochondrocytes that could potentially treat arthritis and other cartilage disorders, facial birth defects, and traumatic injuries to the nose and ears.
In addition to NIAMS, support for the research was provided by the W. M. Keck Foundation, the LEO Foundation, the Chan Zuckerberg Initiative, Horizon Europe, the National Science Foundation, the Simons Foundation, and the UC Irvine Beall Applied Innovation.
Ramos R, Pham KT, Prince RC, et al. Superstable lipid vacuoles endow cartilage with its shape and biomechanics. back...
