Impact of Fetal Exposure to Endocrine Disrupting Chemical Mixtures on FOXA3 Gene and Protein Expression in Adult Rat Testes

Abstract

Perinatal exposure to endocrine disrupting chemicals (EDCs) has been shown to affect male reproductive functions. However, the effects on male reproduction of exposure to EDC mixtures at doses relevant to humans have not been fully characterized. In previous studies, we found that in utero exposure to mixtures of the plasticizer di(2-ethylhexyl) phthalate (DEHP) and the soy-based phytoestrogen genistein (Gen) induced abnormal testis development in rats. In the present study, we investigated the molecular basis of these effects in adult testes from the offspring of pregnant SD rats gavaged with corn oil or Gen + DEHP mixtures at 0.1 or 10 mg/kg/day. Testicular transcriptomes were determined by microarray and RNA-seq analyses. A protein analysis was performed on paraffin and frozen testis sections, mainly by immunofluorescence. The transcription factor forkhead box protein 3 (FOXA3), a key regulator of Leydig cell function, was identified as the most significantly downregulated gene in testes from rats exposed in utero to Gen + DEHP mixtures. FOXA3 protein levels were decreased in testicular interstitium at a dose previously found to reduce testosterone levels, suggesting a primary effect of fetal exposure to Gen + DEHP on adult Leydig cells, rather than on spermatids and Sertoli cells, also expressing FOXA3. Thus, FOXA3 downregulation in adult testes following fetal exposure to Gen + DEHP may contribute to adverse male reproductive outcomes.

Cocktails of NSAIDs and 17α Ethinylestradiol at Environmentally Relevant Doses in Drinking Water Alter Puberty Onset in Mice Intergenerationally

“…Its overexpression suppresses the cAMP-induced expression of NUR77 and its target steroidogenic genes, resulting in decreased production of testosterone [ 73 ] and fertility defects [ 97 ]. Expression of Foxa3 in the testis is also modified upon exposure to DEHP [ 98 ]. The endoribonuclease RNAseL (male F1 DEG ×0.43) plays a role as a tumor suppressor, and polymorphisms in this gene are involved in prostate cancer [ 99 ].…”

Toxicological Effects of Naturally Occurring Endocrine Disruptors on Various Human Health Targets: A Rapid Review

“…Soy consumption is commonplace among oriental populations and has recently become popular also in the western world, thus increasing the toxicological potential of PE-derived N-EDCs. PEs are also present in soy infant formula (SIF) that can be ingested by children [ 31 ]. Food contamination accounted for 32% of the sources of the N-EDCs identified in this study.…”

“…Exposure to isoflavones causes changes in the morphology and physiological functions of the testicles. More specifically, in vivo studies have reported a decrease in testis size [ 31 , 34 ], changes in testis epithelium morphology [ 27 ] and a reduction in the weight of the epididymides, testes and seminal vesicles [ 35 , 36 ]. Mycotoxin administration also leads to a reduction in testicular weight of around 30% [ 12 ].…”

“…According to reports, it has been observed that some embryos did not develop properly or were malformed [ 17 ]. In addition, an increase in fetal death [ 55 ] and potential impairment in growth [ 31 ] and genital development [ 31 ] and low birth weight [ 54 ] have been observed in association with maternal intake of PEs. Szuckiewitz et al found that genistein may interfere with placental growth factor (PlGF) signaling, which can disrupt fetoplacental growth.…”

The Role of Genistein in Mammalian Reproduction

“…Recently, the same authors examined the effect of genistein on the germ cells of adult rats after prenatal exposure using doses typical of human diets. The results of this study indicated that, in utero, low doses of genistein together with DEHP exposure may disrupt the development of testicular cells, including Leydig cells [170]. Recently, in another study, acetaminophen (APAP) and genistein were used individually or in combination to evaluate their effect on two in vitro models of immature Sertoli cells: mouse Sertoli TM4 cells and postnatal day 8 (PND8) rat Sertoli cells.…”