Mechanistic screening of reproductive toxicity in a novel 3D testicular co-culture model shows significant impairments following exposure to low-dibutyl phthalate concentrations

• Published in: Archives of toxicology Vol. 98; no. 8; pp. 2695 - 2709
• Main Authors: Almamoun, Radwa, Pierozan, Paula, Karlsson, Oskar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2024; Springer Nature B.V
• Subjects: Animals; Animals, Newborn; Antiandrogen; Biomedical and Life Sciences; Biomedicine; Biosynthesis; Cell culture; Cholesterol Side-Chain Cleavage Enzyme - metabolism; Coculture Techniques; Contaminants; Dibutyl phthalate; Dibutyl Phthalate - toxicity; Dose-Response Relationship, Drug; Drug development; Environmental Health; Environmental Pollutants - toxicity; Exposure; Germ cells; High-throughput screening; Leydig cells; Leydig Cells - drug effects; Leydig Cells - metabolism; Male; Mechanistic toxicology; Mice; Minipuberty; n-Butyl phthalate; N-Cadherin; Neonates; Occupational Medicine/Industrial Medicine; Pharmacology/Toxicology; Phthalates; Proteins; Reproduction - drug effects; Reproductive health; Reproductive toxicity; Reproductive Toxicology; Risk assessment; RNA-binding protein; Screening; Sertoli cells; Sertoli Cells - drug effects; Sertoli Cells - metabolism; Sox9 protein; Spermatogenesis; Testes; Testis - drug effects; Testis - metabolism; Testosterone; Testosterone - metabolism; Three dimensional models; Toxicants; Toxicity; Zonula occludens-1 protein; Testosterone; Antiandrogen; Minipuberty; Spermatogenesis; Reproductive toxicity; Mechanistic toxicology
• ISSN: 0340-5761; 1432-0738; 1432-0738
• DOI: 10.1007/s00204-024-03767-6

To improve the mechanistic screening of reproductive toxicants in  chemical-risk assessment and drug development, we have developed a three-dimensional (3D) heterogenous testicular co-culture model from neonatal mice. Di-n-butyl phthalate (DBP), an environmental contaminant that can affect reproductive health negatively, was used as a model compound to illustrate the utility of the in vitro model. The cells were treated with DBP (1 nM to 100 µM) for 7 days. Automated high-content imaging confirmed the presence of cell-specific markers of Leydig cells (CYP11A1 +), Sertoli cells (SOX9 +), and germ cells (DAZL +). Steroidogenic activity of Leydig cells was demonstrated by analyzing testosterone levels in the culture medium. DBP induced a concentration-dependent reduction in testosterone levels and decreased the number of Leydig cells compared to vehicle control. The levels of steroidogenic regulator StAR and the steroidogenic enzyme CYP11A1 were decreased already at the lowest DBP concentration (1 nM), demonstrating upstream effects in the testosterone biosynthesis pathway. Furthermore, exposure to 10 nM DBP decreased the levels of the germ cell-specific RNA binding protein DAZL, central for the spermatogenesis. The 3D model also captured the development of the Sertoli cell junction proteins, N-cadherin and Zonula occludens protein 1 (ZO-1), critical for the blood–testis barrier. However, DBP exposure did not significantly alter the cadherin and ZO-1 levels. Altogether, this 3D in vitro system models testicular cellular signaling and function, making it a powerful tool for mechanistic screening of developmental testicular toxicity. This can open a new avenue for high throughput screening of chemically-induced reproductive toxicity during sensitive developmental phases.