A team of researchers at the School of Medicine led by Sarven Sabunciyan, Assistant Professor of Pediatrics, discovered that changes in mRNA communication through extracellular vesicles are connected to postpartum depression. The team’s findings were published in Molecular Psychiatry, which further details their impact on the field.
Traditionally, medical research has focused on analyzing the behaviors inside cells and how cells change with disease. However, Sabunciyan’s team discovered that processes outside the cell can also influence the risk of diseases like postpartum depression — a distinct type of depression among mothers beginning after childbirth.
Sabunciyan’s research focuses on extracellular vesicles and sequencing, which put him in contact with Lauren Osborne, Vice Chair for Clinical Research in Obstetrics and Gynecology at Weill Cornell Medicine. Osborne, whose research focuses on postpartum depression, and Sabunciyan combined their research areas to collaborate on a study on extracellular vesicles in the context of postpartum depression.
Sabunciyan discussed this research further in an interview with The News-Letter.
“Cells release extracellular vesicles, and these vesicles carry RNA, some DNA and protein cargos that go between cells,” he said. “One cell releases it and another cell picks it up which is a way cells can signal each other.”
He explained that this type of communication plays an essential role in pregnancy as it occurs between the mother’s and baby’s cells, which led the researchers to believe it could be involved in postpartum depression.
“We know this is important because when the extracellular vesicle signaling gets altered or is abnormal, it results in diseases like preterm birth, gestational diabetes and pre-eclampsia,” he said.
The research team analyzed blood samples of 43 women from pregnancy up to six months after birth. They compared the mRNA content in extracellular vesicles between women who developed postpartum depression and those who did not.
Sabunciyan outlined the team’s observations from the experiment.
“We saw that the levels of mRNA in vesicles in blood were vastly different between women who went on to develop postpartum depression and controls. Also, the vast majority of the differences were in pregnancy,” he said.
In an interview with The News-Letter, Osborne highlighted that postpartum depression is unique among psychiatric disorders because there is an explicit biological event that precedes the illness.
“The postpartum period is really the only time in a person’s life we have a clearly defined biological trigger for the mental illness,” she said. “By studying the biology of postpartum depression, we might be able to figure out biological causes and mechanisms that we then may be able to apply to mental illness at other times as well.”
She stressed the importance of research on postpartum depression given its prevalence, with one-in-seven women developing severe symptoms of the condition.
She discussed the impact of the team’s findings on predicting the risk of postpartum depression.
“We might be able to develop a clinical biomarker where we could draw blood from women during pregnancy and know who’s going to be at risk and therefore target our interventions,” she said.
Additionally, the researchers discovered that these extracellular vesicle changes are related to autophagy, a process where cells clean themselves out and get rid of aging organelles.
According to Sabunciyan, selective serotonin reuptake inhibitors (SSRIs), which are used as antidepressants, have been shown to affect autophagy.
“The signatures of the sequenced mRNAs suggest that this process, autophagy, is reduced in postpartum depression,” he said. “If we are right about autophagy, we could potentially repurpose drugs that affect autophagy to address psychiatric disorders.”
The team is working on improving the ease of administering a test for the risk of postpartum depression, which would only need to measure five to 10 salient mRNAs instead of the thousands currently measured.
Osborne hopes to look at a more diverse population in future studies.
“This population was very largely white and upper-middle class, so we want to extend it to other populations and make sure that the findings still hold true across a racially, ethically and socioeconomically diverse population,” she said.