More than red blood cells depend on hemoglobin, surprising study of cartilage reveals

Blood is red because it’s brimming with the oxygen-toting protein hemoglobin, but scientists have long wondered whether cells outside of the bloodstream depend on this protein as well. Now, a team of researchers from China has demonstrated that cartilage-making cells called chondrocytes manufacture and use hemoglobin, perhaps to help them survive in cartilage’s oxygen-poor environment. The results surprised bone researchers, but they give the study high marks. The authors “provide solid and convincing evidence that chondrocytes can produce hemoglobin and that it has a physiological role,” says bone developmental biologist Ernestina Schipani of the University of Pennsylvania Perelman Medical School, who wasn’t connected to the research. “I admire that they picked up on an unusual finding and expanded it into a comprehensive story,” adds bone biologist Noriaki Ono of the University of Texas Health Science Center at Houston, who also had no role in the study. Red blood cells are about 95% hemoglobin, which makes sense because their main job is to ferry the oxygen that sustains the body’s tissues. Researchers have detected hemoglobin in an assortment of other cell types, including neurons, lung cells, and immune cells called macrophages, but so far they haven’t found conclusive evidence that the protein performs a vital role for these cells. Scientists had not previously reported finding hemoglobin in chondrocytes. In 2017, however, patho...
Source: ScienceNOW - Category: Science Source Type: news