Germ cell apoptosis regulation is pivotal in order to maintain proper daily sperm production. Several reports have shown that endocrine disruptors such as Bisphenol-A (BPA) and Nonylphenol (NP) induce germ cell apoptosis along with a decrease in sperm production. Given their ubiquitous distribution in plastic products used by humans it is important to clarify their mechanism of action. TACE/ADAM17 is a widely distributed extracellular metalloprotease and participates in the physiological apoptosis of germ cells during spermatogenesis. The aims of this work were: 1) to determine whether BPA and NP induce ADAM17 activation; and 2) to study whether ADAM17 and/or ADAM10 are involved in germ cell apoptosis induced by BPA and NP in the pubertal rat testis. A single dose of BPA or NP (50 mg/kg) induces germ cell apoptosis in 21-day-old male rats, which was prevented by a pharmacological inhibitor of ADAM17, but not by an inhibitor of ADAM10. In vitro, we showed that BPA and NP, at similar concentrations to those found in human samples, induce the shedding of exogenous and endogenous (TNF-α) ADAM17 substrates in primary rat Sertoli cell cultures and TM4 cell line. In addition, pharmacological inhibitors of metalloproteases and genetic silencing of ADAM17 prevent the shedding induced in vitro by BPA and NP. Finally, we showed that in vivo BPA and NP induced early activation (phosphorylation) of p38 MAPK and translocation of ADAM17 to the cell surface. Interestingly, the inhibition of p38 MAPK prevents germ cell apoptosis and translocation of ADAM17 to the cell surface. These results show for the first time that xenoestrogens can induce activation of ADAM17 at concentrations similar to those found in human samples, suggesting a mechanism by which they could imbalance para/juxtacrine cell-to-cell-communication and induce germ cell apoptosis.

Constitutive germ cell apoptosis during mammalian spermatogenesis is a key process for controlling sperm output and to eliminate damaged or unwanted cells. An increase or decrease in the apoptosis ...

Endocrine-disruptor chemicals (EDCs), such as bisphenol A (BPA) and nonylphenol (NP), have been widely studied due to their negative effects on human and wildlife reproduction. Exposure to BPA or NP is related to cell death, hormonal deregulation, and cancer onset. Our previous studies showed that both compounds induce A Disintegrin And Metalloprotease 17 (ADAM17) activation. Here, we show that BPA and NP induce apoptosis in prostate and ovary cancer cell lines, in a process dependent on ADAM17 activation. ADAM17 knockdown completely prevented apoptosis as well as the shedding of ADAM17 substrates. Both compounds were found to induce an increase in intracellular calcium (Ca²⁺) only in Ca²⁺-containing medium, with the NP-treated cells response being more robust than those treated with BPA. Additionally, using a phosphorylated protein microarray, we found that both compounds stimulate common intracellular pathways related to cell growth, differentiation, survival, and apoptosis. These results suggest that BPA and NP could induce apoptosis through ADAM17 by activating different intracellular signaling pathways that may converge in different cellular responses, one of which is apoptosis. These results confirm the capacity of these compounds to induce cell apoptosis in cancer cell lines and uncover ADAM17 as a key regulator of this process in response to EDCs.

The development of nonopioid analgesics for the treatment of abdominal pain is a pressing clinical problem. To address this, we examined the expression of G_i/o-coupled receptors, which typically inhibit nociceptor activation, in colonic sensory neurons. This led to the identification of the orphan receptor GPR35 as a visceral analgesic drug target because of its marked coexpression with transient receptor potential ankyrin 1 (TRPA1), a mediator of noxious mechanotransduction in the bowel. Building on in silico docking simulations, we confirmed that the mast cell stabiliser, cromolyn (CS), and phosphodiesterase inhibitor, zaprinast, are agonists at mouse GPR35, promoting the activation of different G_i/o subunits. Pretreatment with either CS or zaprinast significantly attenuated TRPA1-mediated colonic nociceptor activation and prevented TRPA1-mediated mechanosensitisation. These effects were lost in tissue from GPR35^−/− mice and were shown to be mediated by inhibition of TRPA1-evoked substance P (SP) release. This observation highlights the pronociceptive effect of SP and its contribution to TRPA1-mediated colonic nociceptor activation and sensitisation. Consistent with this mechanism of action, we confirmed that TRPA1-mediated colonic contractions evoked by SP release were abolished by CS pretreatment in a GPR35-dependent manner. Our data demonstrate that GPR35 agonists prevent the activation and sensitisation of colonic nociceptors through the inhibition of TRPA1-mediated SP release. These findings highlight the potential of GPR35 agonists to deliver nonopioid analgesia for the treatment of abdominal pain.

Extracellular metolloproteases have been implied in different process such as cell death, differentiation and migration. Membrane-bound metalloproteases of the ADAM family shed the extracellular domain of many cytokines and receptor controlling auto and para/juxtacrine cell signaling in different tissues. ADAM17 and ADAM10 are two members of this family surface metalloproteases involved in germ cell apoptosis during the first wave of spermatogenesis in the rat, but they have other signaling functions in somatic tissues. In an attempt to further study these two enzymes, we describe the presence and localization in adult male rats. Results showed that both enzymes are detected in germ and Sertoli cells during all the stages of spermatogenesis. Interestingly their protein levels and cell surface localization in adult rats were stage-specific, suggesting activation of these enzymes at particular events of rat spermatogenesis. Therefore, these results show that ADAM10 and ADAM17 protein levels and subcellular (cell surface) localization are regulated during rat spermatogenesis.