Dr. Dennery is a pediatrician who focuses on newborn infants and the Chair of Pediatrics at Warren Alpert School of Medicine. Her research focuses on lung problems in infants born prematurely.

Dr. Dennery received her undergraduate degree from McGill University in Montreal and her medical degree from Howard University. She completed her residency at Children’s National Medical Center in Washington DC and trained as a neonatologist at Case Western Reserve University in Cleveland. After completing her training, she was a faculty member at Stanford University for 13 years before being recruited to be the Chair of Pediatrics of the Children’s Hospital of Philadelphia. She moved to Brown in 2015.

Premature infants often have severe lung problems due to a number of different interacting factors. Often these babies are put on machines that help them breathe for a period of time until their lungs are more developed. However, being on a ventilator for too long can itself cause lung injury due to oxygen toxicity. Oxygen travels through the blood inside of hemoglobin, which is made up of a heme molecule and a globin molecule. However, when too much oxygen is present, the hemoglobin will break down and by itself is very toxic. To protect against heme, the body will start making a chemical called heme oxygenase (HO), which gets rid of the heme.

Newborn lungs make a lot of HO, which is thought to help protect them while their lungs finish developing after birth. However, unlike adult lungs, which make more HO when there’s more oxygen, the amount HO in an infant’s lung does not really respond to oxygen level.

Dr. Dennery has done work to investigate why that is — and to figure out what is determining the levels of HO in newborn lungs. Specifically, she has shown that a protein called Bach1 regulates HO levels, by blocking the gene that encodes HO from being transcribed into RNA. In a very recent paper, she then looked into why newborn lungs have so much Bach1 relative to other tissues. She identified a micro-RNA (a small piece of RNA that regulates other genes by binding to their RNA transcripts) which normally decreases Bach1 levels, allowing HO to build up and do its protective job. However, under conditions of high oxygen, levels of this microRNA are decreased, allowing Bach1 to build up and suppress HO.