PROJECT SUMMARY/ABSTRACT: Dolutegravir (DTG)-based antiretroviral therapy (ART) is recommended by the World Health Organization for all people living with HIV, including pregnant women. Surveillance data from Botswana reported a 3-fold increased incidence of neural tube defects (NTDs) in women taking DTG from conception. Other studies have not detected this association although none were sufficiently powered. Concern over the clinical significance of the association between DTG and NTDs has created uncertainty in the treatment of women with HIV globally. Data from animal DTG fetotoxicity studies in our lab support the Botswana findings and suggest that DTG at a dose yielding clinically relevant plasma levels (1x-DTG) is associated with a modest but significantly increased risk of a variety of congenital defects including NTDs. Unexpectedly, we observe fewer fetal anomalies (similar to control) in mice treated with a 5x-DTG dose. Maternal folate deficiency, pre-gestational diabetes, and pre- pregnancy obesity are established NTD risk factors. Excessive weight gain is reported in persons initiating or switching to DTG. Excess weight gain and the underlying metabolic alterations could be a mechanism by which DTG increases NTD rates. We will use well-controlled animal studies and clinical samples from Botswana to perform an unbiased omics approach to identify potential pathways through which DTG may induce fetal defects. In addition, we will take a targeted approach, involving murine in vivo and embryo culture models, to investigate the impact of DTG on folate, glucose, and oxidative stress as potential pathways leading to DTG- associated fetal defects. In Aim 1 we will identify and validate maternal and fetal metabolic factors modified by DTG exposure that increase or reduce the risk for NTDs and other fetal anomalies by: (1) performing a metabolomics screen of pregnant mice and their fetuses treated with DTG-based ART (1x-DTG and 5x-DTG) or control for indicators of fetal anomaly risk or protection; (2) screening for metabolic differences in pregnant women with HIV on DTG-based ART from conception, compared with those on efavirenz-based ART from conception, and with HIV-negative pregnant women; (3) validating candidate metabolites using murine in vivo and embryo culture systems. In Aim 2 we will perform experimental studies to determine the mechanism(s) by which DTG increased the risk of fetal anomalies. We will examine the impact of DTG on: (1) folate metabolism; (2) glucose homeostasis; (3) oxidative stress and mitochondrial function, using murine in vivo and embryo culture systems. We will leverage resources of an existing prospective pregnancy study in Botswana (NIH/NICHD K23 HD088230-01A1 – PI: Dr. Zash), and take advantage of Dr. Serghides' robust mouse pregnancy model of ART safety, Drs. Copp and Greene's renowned expertise in models of NTDs, and the omics expertise of Metabolon, Dr. Jao, and Dr. Coburn to successfully complete this project. Our study will be the first to examine associations between DTG and metabolic alterations as a mechanism underlying DTG- associated congenital defects.

PROJECT NARRATIVE Treatment with dolutegravir from conception has been associated with increased risk for neural tube defects, which has created uncertainty over the use of dolutegravir in the treatment of women of reproductive age living with HIV. Dolutegravir has also been associated with excess weight gain, a known risk factor for neural tube defects, suggesting that dolutegravir-associated metabolic alterations could contribute to the increased risk for neural tube defects. We will study the association of dolutegravir use in pregnancy with maternal and fetal metabolic alterations and the contribution to fetal defects, using murine in vivo and embryo culture models, and clinical samples from a pregnancy study in Botswana.