Fetal glucocorticoid exposure leads to sex‐specific changes in drug‐transporter function at the blood‐brain barrier in juvenile guinea pigs

Bloise

Matthews

2023

Fluids Barriers CNS

Background The multidrug resistance (MDR) transporters, P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) contribute to the blood–brain barrier (BBB), protecting the brain from drug exposure. The impact of infection on MDR in the developing human BBB remains to be determined. We hypothesized that exposure to bacterial and viral pathogen-associated molecular patterns (PAMPs) modify MDR expression and activity in human fetal brain endothelial cells (hfBECs) isolated from early and mid-gestation brain microvessels. Methods We modelled infection (4 h and 24 h) using the bacterial PAMP, lipopolysaccharide (LPS; a toll-like receptor [TLR]-4 ligand) or the viral PAMPs, polyinosinic polycytidylic acid (Poly I:C; TLR-3 ligand) and single-stranded RNA (ssRNA; TLR-7/8 ligand). mRNA expression was assessed by qPCR, whereas protein expression was assessed by Western blot or immunofluorescence. P-gp and BCRP activity was evaluated by Calcein-AM and Chlorin-6 assays. Results TLRs-3,4 and 8 were expressed by the isolated hfBECs. Infection mimics induced specific pro-inflammatory responses as well as changes in P-gp/ABCB1 or BCRP/ABCG2 expression (P < 0.05). LPS and ssRNA significantly decreased P-gp activity at 4 and 24 h in early and mid-gestation (P < 0.03-P < 0.001), but significantly increased BCRP activity in hfBECs in a dose-dependent pattern (P < 0.05-P < 0.002). In contrast, Poly-IC significantly decreased P-gp activity after 4 h in early (P < 0.01) and mid gestation (P < 0.04), but not 24 h, and had no overall effect on BCRP activity, though BCRP activity was increased with the highest dose at 24 h in mid-gestation (P < 0.05). Conclusions Infectious PAMPs significantly modify the expression and function of MDR transporters in hfBECs, though effects are PAMP-, time- and dose-specific. In conclusion, bacterial and viral infections during pregnancy likely have profound effects on exposure of the fetal brain to physiological and pharmacological substrates of P-gp and BCRP, potentially leading to altered trajectories of fetal brain development.

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effects of bacterial and viral pathogen-associated molecular patterns (PAMPs) on multidrug resistance (MDR) transporters in brain endothelial cells of the developing human blood–brain barrier

Bloise

Matthews

2023

Fluids Barriers CNS

“…Due to the very limited availability of human fetal brain tissue for research, our sample size was relatively small ( n = 6/group). However, it is important to point out that a sample size of six per group (or less in specific cases) has been sufficient to show statistical alterations in P-gp protein/ ABCB1 mRNA and BCRP protein/ ABCG2 mRNA levels and/or function in human [ 16 , 30 , 31 , 53 , 62 , 63 ] and in animal gestational tissues [ 15 , 62 , 63 , 64 ]. In the current study, we were unable to collect any clinical information (apart from gestational age) about the elective pregnancy terminations (mandated by our REB).…”

Section: Discussionmentioning

confidence: 99%

Functional Expression of Multidrug-Resistance (MDR) Transporters in Developing Human Fetal Brain Endothelial Cells

Bloise

Império

et al. 2022

Cells

Self Cite

There is little information about the functional expression of the multidrug resistance (MDR) transporters P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) in the developing blood–brain barrier (BBB). We isolated and cultured primary human fetal brain endothelial cells (hfBECs) from early and mid-gestation brains and assessed P-gp/ABCB1 and BCRP/ABCG2 expression and function, as well as tube formation capability. Immunolocalization of the von Willebrand factor (marker of endothelial cells), zonula occludens-1 and claudin-5 (tight junctions) was detected in early and mid-gestation-derived hfBECs, which also formed capillary-like tube structures, confirming their BEC phenotype. P-gp and BCRP immunostaining was detected in capillary-like tubes and in the cytoplasm and nucleus of hfBECs. P-gp protein levels in the plasma membrane and nuclear protein fractions, as well as P-gp protein/ABCB1 mRNA and BCRP protein levels decreased (p < 0.05) in hfBECs, from early to mid-gestation. No differences in P-gp or BCRP activity in hfBECs were observed between the two age groups. The hfBECs from early and mid-gestation express functionally competent P-gp and BCRP drug transporters and may thus contribute to the BBB protective phenotype in the conceptus from early stages of pregnancy.

“…This is due to the fact that availability of human fetal brain specimens for research is extremally limited. However, previous research investigating drug transporter expression and function in developing tissues has utilized a sample size of six per group in human 8,47,48,50,[63][64][65] and animal [66][67][68][69] studies. As mandated by the REB, we are unable to retrieve clinical information on the fetal tissues collected.…”

Section: Limitations Of the Studymentioning

confidence: 99%

Hypoxia modulates P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) drug transporters in brain endothelial cells of the developing human blood-brain barrier

Mughis

Império

et al. 2023

Preprint

Self Cite

P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) are two multidrug resistance (MDR) transporters expressed at the blood-brain barrier (BBB). They confer protection against entry of harmful molecules into the fetal brain. The fetus develops under relatively low oxygen concentrations; however, pregnancy disorders (including pre-eclampsia) may lead to even lower intrauterine oxygen levels. We investigated the effects of hypoxia on transporter expression and activity in human fetal brain endothelial cells (hfBECs) isolated in early and mid-gestation. Results indicate decreased BCRP protein and activity under hypoxia in early-gestation hfBECs. Mid-gestation hfBECs exhibited an increase in P-gp and BCRP activity following hypoxia. Results suggest a hypoxia-induced reduction in fetal brain protection in early-pregnancy, but a potential increase in transporter-mediated protection at the BBB during mid-gestation. This would modify accumulation of various key P-gp and BCRP physiological and pharmacological substrates in the developing fetal brain and may play a role in the pathogenesis of neurodevelopmental disorders commonly associated with in utero hypoxia.