Peter J. Ratcliffe, (born May 14, 1954, Lancashire, England), British physician and scientist known for his research into the regulation of erythropoietin, a hormone that stimulates red blood cell production in response to low blood oxygen levels, and for his research into the mechanisms cells use to sense oxygen.

His discoveries pertaining to cellular oxygen-sensing mechanisms earned him a share of the 2019 Nobel Prize for Physiology or Medicine (shared with American scientists William G. Kaelin, Jr., and Gregg L. Semenza).

 

Ratcliffe attended Lancaster Royal Grammar School from 1965 to 1971 and later studied medicine at Gonville & Caius College, Cambridge.

In 1978 he completed bachelor’s degrees in medicine and surgery at St. Bartholomew’s Hospital in London, and in 1987 he graduated from Cambridge with a medical degree.

He subsequently went to the University of Oxford to study renal medicine with a particular interest in oxygen delivery to renal tissues. In 1989 he established a laboratory at Oxford in order to focus his research specifically on cellular oxygen-sensing pathways and erythropoietin regulation. From 2004 to 2016 he served as head of the Nuffield Department of Medicine at Oxford. In 2016 he was appointed director of Oxford’s Target Discovery Institute and clinical research director at the Francis Crick Institute, London.

 

In the late 1980s and early 1990s, when Ratcliffe was starting his research, it was known that erythropoeitin is produced by kidney cells when blood oxygen levels are reduced.

However, Ratcliffe’s investigations of erythropoeitin production led to the realization that cells in multiple other organs, including the brain and the liver, also are equipped with oxygen-sensing abilties.

He also found that cellular responses to oxygen availability affect other processes in cells, such as differentiation and metabolism. In particular, Ratcliffe and Kaelin, working independently, discovered that a chemical modification known as prolyl hydroxylation on a molecule called hypoxia-inducible factor (HIF) dictates how cells respond to changes in oxygen levels.

When the modification is present, HIF is marked for degradation. When absent, HIF persists, and key cellular processes are altered to facilitate adaptation to hypoxic conditions, thereby enabling cells to continue to grow and replicate. The findings were especially significant for their impact on scientists’ understanding of cancer: tumours often thrive under hypoxic conditions, which is in large part due to elevated HIF activity.

 

In addition to receiving the Nobel Prize, Ratcliffe was honoured with various other awards during his career. In 2010 he received the Canada Gairdner International Award, and in 2016 he shared the Albert Lasker Basic Medical Research Award with Kaelin and Semenza. He was elected to the Royal Society in 2002 and was knighted in 2014.