Expression, regulation, and function of drug transporters in cervicovaginal tissues of a mouse model used for microbicide testing

Abstract

P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance protein 4 (MRP4) are three efflux transporters that play key roles in the pharmacokinetics of antiretroviral drugs used in the pre-exposure prophylaxis of HIV sexual transmission. In this study, we investigated the expression, regulation, and function of these transporters in cervicovaginal tissues of a mouse model. Expression and regulation were examined using real-time RT-PCR and immunohistochemical staining, in the mouse tissues harvested at estrus and diestrus stages under natural cycling or after hormone synchronization. The three transporters were expressed at moderate to high levels compared to the liver. Transporter proteins were localized in various cell types in different tissue segments. Estrous cycle and exogenous hormone treatment affected transporter mRNA and protein expression, in a tissue- and transporter-dependent manner. Depo-Provera-synchronized mice were dosed vaginally or intraperitoneally with 3H-TFV, with or without MK571 co-administration, to delineate the function of cervicovaginal Mrp4. Co-administration of MK571 significantly increased the concentration of vaginally-administered TFV in endocervix and vagina. MK571 increased the concentration of intraperitoneally-administered TFV in the cervicovaginal lavage and vagina by several fold. Overall, P-gp, Bcrp, and Mrp4 were positively expressed in mouse cervicovaginal tissues, and their expression can be regulated by the estrous cycle or by exogenous hormones. In this model, the Mrp4 transporter impacted TFV distribution in cervicovaginal tissues.

Pharmacology of Antiretrovirals in the Female Genital Tract for HIV Prevention

“…The presence of high MRP4 in vaginal epithelium compared to colorectal epithelium at both genetic and protein level may account for the increased accumulation of tenofovir in the colorectal compared to cervicovaginal mucosa . This is consistent with functional studies performed in a mouse model that found that MRP4 inhibitors significantly affected the disposition of tenofovir gel in genital tissues . Similarly, the presence of P‐gp in vaginal mucosa may indicate difficulty in reaching appropriate drug concentration within the female genital tract, as several ARVs being considered for PrEP, including maraviroc, darunavir, raltegravir, and cabotegravir, have been identified substrates of P‐gp .…”

“…13 This is consistent with functional studies performed in a mouse model that found MRP4 inhibitors significantly affected the disposition of tenofovir gel in genital tissues. 23 Similarly, the presence of P-gp in vaginal mucosa may indicate difficulty in reaching appropriate drug concentration within the FGT as several ARVs being considered for PrEP, including maraviroc, darunavir, raltegravir, and cabotegravir, have been identified substrates of P-gp 15,24 . With the exception of cabotegravir, these drugs appear to penetrate well to the FGT although, exposures are consistently lower than in colorectal tissue 25,26 , consistent with higher P-gp expression observed in vaginal tissue over colorectal tissue at mRNA level.…”

Phase 2a Safety, Pharmacokinetics, and Acceptability of Dapivirine Vaginal Rings in US Postmenopausal Women

“…For example, postmenopausal women have been found to have decreased ABCB1 (P-glycoprotein) expression in the vagina compared to premenopausal women [28]. Differences in drug transporter expression by phase of estrous cycle have been seen in a mouse model [29]. Changes in uptake or efflux drug transporters may have resulted in our findings of decreased DPV concentrations in cervical tissue; however, the drug transporters involved in DPV distribution are not yet known [30,31].…”

Overactivated sonic hedgehog signaling aggravates intrauterine adhesion via inhibiting autophagy in endometrial stromal cells

“…The menstrual cycles of all candidate female mice were synchronized by intraperitoneal administration of pregnant mare serum gonadotrophin (PMSG, 5 IU/20 g) 70 . Three days later, a short stumpy uterus made it easy to establish a murine IUA model by electrocoagulation, which was marked as day 0, as previously described 71 .…”