Dolutegravir induces FOLR1 expression during brain organoid development.

During the first month of pregnancy, the brain and spinal cord are formed through a process called neurulation. However, this process can be altered by low serum levels of folic acid, environmental factors, or genetic predispositions. In 2018, a surveillance study in Botswana, a country with a high incidence of human immunodeficiency virus (HIV) and lacking mandatory food folate fortification programs, found that newborns whose mothers were taking dolutegravir (DTG) during the first trimester of pregnancy had an increased risk of neural tube defects (NTDs). As a result, the World Health Organization and the U.S. Food and Drug Administration have issued guidelines emphasizing the potential risks associated with the use of DTG-based antiretroviral therapies during pregnancy. To elucidate the potential mechanisms underlying the DTG-induced NTDs, we sought to assess the potential neurotoxicity of DTG in stem cell-derived brain organoids. The gene expression of brain organoids developed in the presence of DTG was analyzed by RNA sequencing, Optical Coherence Tomography (OCT), Optical Coherence Elastography (OCE), and Brillouin microscopy. The sequencing data shows that DTG induces the expression of the folate receptor (FOLR1) and modifies the expression of genes required for neurogenesis. The Brillouin frequency shift observed at the surface of DTG-exposed brain organoids indicates an increase in superficial tissue stiffness. In contrast, reverberant OCE measurements indicate decreased organoid volumes and internal stiffness.

Dolutegravir-induced neural tube defects in mice are folate responsive.

OBJECTIVES: In 2018, the Botswana Tsepamo Study reported a nine-fold increased risk of neural tube defects in infants whose mothers were treated with dolutegravir (DTG) from the time of conception. As maternal folate supplementation and status is a well known modifier of neural tube defect (NTD) risk, we sought to evaluate birth outcomes in mice fed normal and low folic acid diets treated with DTG during pregnancy. DESIGN: DTG was evaluated for developmental toxicity using pregnant mice fed normal or low folic acid diet. METHODS: CD-1 mice were provided diet with normal (3 mg/kg) or low (0.3 mg/kg) folic acid. They were treated with water, a human therapeutic-equivalent dose, or supratherapeutic dose of DTG from mouse embryonic day E6.5 to E12.5. Pregnant dams were sacrificed at term (E18.5) and fetuses were inspected for gross, internal, and skeletal defects. RESULTS: Fetuses with exencephaly, an NTD, were present in both therapeutic human equivalent and supratherapeutic exposures in dams fed low folic acid diet. Cleft palates were also found under both folate conditions. CONCLUSIONS: Recommended dietary folic acid levels during mouse pregnancy ameliorate developmental defects that arise from DTG exposure. Since low folate status in mice exposed to DTG increases the risk for NTDs, it is possible that DTG exposures in people living with HIV with low folate status during pregnancy may explain, at least in part, the elevated NTD risk signal observed in Botswana. Based on these results, future studies should consider folate status as a modifier for DTG-associated NTD risk.

Gene Environment Interactions in the Etiology of Neural Tube Defects.

Human structural congenital malformations are the leading cause of infant mortality in the United States. Estimates from the United States Center for Disease Control and Prevention (CDC) determine that close to 3% of all United States newborns present with birth defects; the worldwide estimate approaches 6% of infants presenting with congenital anomalies. The scientific community has recognized for decades that the majority of birth defects have undetermined etiologies, although we propose that environmental agents interacting with inherited susceptibility genes are the major contributing factors. Neural tube defects (NTDs) are among the most prevalent human birth defects and as such, these malformations will be the primary focus of this review. NTDs result from failures in embryonic central nervous system development and are classified by their anatomical locations. Defects in the posterior portion of the neural tube are referred to as meningomyeloceles (spina bifida), while the more anterior defects are differentiated as anencephaly, encephalocele, or iniencephaly. Craniorachischisis involves a failure of the neural folds to elevate and thus disrupt the entire length of the neural tube. Worldwide NTDs have a prevalence of approximately 18.6 per 10,000 live births. It is widely believed that genetic factors are responsible for some 70% of NTDs, while the intrauterine environment tips the balance toward neurulation failure in at risk individuals. Despite aggressive educational campaigns to inform the public about folic acid supplementation and the benefits of providing mandatory folic acid food fortification in the United States, NTDs still affect up to 2,300 United States births annually and some 166,000 spina bifida patients currently live in the United States, more than half of whom are now adults. Within the context of this review, we will consider the role of maternal nutritional status (deficiency states involving B vitamins and one carbon analytes) and the potential modifiers of NTD risk beyond folic acid. There are several well-established human teratogens that contribute to the population burden of NTDs, including: industrial waste and pollutants [e.g., arsenic, pesticides, and polycyclic aromatic hydrocarbons (PAHs)], pharmaceuticals (e.g., anti-epileptic medications), and maternal hyperthermia during the first trimester. Animal models for these teratogens are described with attention focused on valproic acid (VPA; Depakote). Genetic interrogation of model systems involving VPA will be used as a model approach to discerning susceptibility factors that define the gene-environment interactions contributing to the etiology of NTDs.

Impact of sediment parameters in the prediction of benthic microbial fuel cell performance.

The benthic microbial fuel cell (BMFC) is a promising technology for harvesting renewable energy from marine littoral environments. The scientific community has researched BMFC technology for well over a decade, but the in situ performance remains challenging. To address this challenge, BMFC power experiments were performed on sediment collected from San Diego Bay (CA, USA), La Spezia (Italy) and Honolulu (HI, USA) in the ever-changing littoral environment. Analysis of BMFC laboratory data found the power density varied substantially across 11 sites in San Diego Bay. In addition, data from experiments repeated at four locations in San Diego Bay showed significant differences between experiments performed in 2014, 2016 and 2019. Multivariable linear analysis showed BMFC 90 day cumulative power density was positively correlated with the total organic carbon (p < 0.05) and negatively correlated with the black carbon in the sediment (p < 0.05). Regression coefficients trained on the San Diego Bay data from 2014 facilitated accurate predictions of BMFC performance in 2016 and 2019. The modeling paradigm accurately explained variations in BMFC power performance in La Spezia and showed sediment parameters can impact BMFC performance differently across geographic regions. The results demonstrate a great potential to use sediment parameters and statistical modeling to predict BMFC power performance prior to deployment in oceanographic environments, thereby reducing cost, work force and resources.

The antagonism of folate receptor by dolutegravir: developmental toxicity reduction by supplemental folic acid.

OBJECTIVE: Maternal folate (vitamin B9) status is the largest known modifier of neural tube defect risk, so we evaluated folate-related mechanisms of action for dolutegravir (DTG) developmental toxicity. DESIGN: Folate receptor 1 (FOLR1) was examined as a target for DTG developmental toxicity using protein and cellular interaction studies and an animal model. METHODS: FOLR1 competitive binding studies were used to test DTG for FOLR1 antagonism. Human placenta cell line studies were used to test interactions with DTG, folate, and cations. Zebrafish were selected as an animal model to examine DTG-induced developmental toxicity and rescue strategies. RESULTS: FOLR1 binding studies indicate DTG is a noncompetitive FOLR1 antagonist at therapeutic concentrations. In-vitro testing indicates calcium (2 mmol/l) increases FOLR1-folate interactions and alters DTG-FOLR1-folate interactions and cytotoxicity. DTG does not inhibit downstream folate metabolism by dihydrofolate reductase. Early embryonic exposure to DTG is developmentally toxic in zebrafish, and supplemental folic acid can mitigate DTG developmental toxicity. CONCLUSION: Folates and FOLR1 are established modifiers of risk for neural tube defects, and binding data indicates DTG is a partial antagonist of FOLR1. Supplemental folate can ameliorate increased developmental toxicity due to DTG in zebrafish. The results from these studies are expected to inform and guide future animal models and clinical studies of DTG-based antiretroviral therapy in women of childbearing age.