Mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cell injury in peripubertal rodents results in the stimulation of germ cell apoptosis through an interaction of FAS/FASL between these two cell types. During this peripubertal period, an early spike in the incidence of germ cell apoptosis occurs during the first wave of spermatogenesis and is essential for the development of functional spermatogenesis in adults. Our previous observations revealed that soluble tumor necrosis factor alpha (sTNFA) released by germ cells after MEHP exposure consequently resulted in a robust induction of FASL by Sertoli cells. Metalloproteinases (MPs) are essential for processing the TNFA precursor to its soluble form and its ability to bind to TNFRSF1A. The activity of MPs is regulated by the tissue inhibitors of MPs (TIMPs) family. Herein we report that TIMP2 is predominately expressed in Sertoli cells and that protein levels decrease in a time-dependent manner after MEHP exposure. The secretion of matrix MP 2 (MMP2) in primary rat Sertoli cell-germ cell cocultures is induced after MEHP exposure, and its activity increases in a time-dependent manner. The addition of SB-3CT, a specific gelatinase inhibitor, decreases the activity of MMP2 and significantly reduces MEHP-enhanced sTNFA production in primary cocultures. In vivo challenges with SB-3CT decrease sTNFA and reduce MEHP-induced testicular germ cell apoptosis. In primary cocultures, MEHP exposure causes a 9.46-fold increase in sTNFA, while the addition of recombinant MMP2 protein results in a 5.4-fold increase in sTNFA, suggesting that MEHP-induced MMP2 is in part responsible for the activation of TNFA in the testis. Taken together, these observations indicate the distinct role of specific MPs in response to toxicant-induced Sertoli cell injury, providing further insights into the mechanism by which Sertoli cells control the sensitivity of germ cells to undergo apoptosis.

Tight junctions between Sertoli cells of the testicular seminiferous epithelium establishes the blood-testis barrier (BTB) and creates a specialized adluminal microenvironment above the BTB that is required for the development of the germ cells that reside there. Actin filament-based anchoring junctions between Sertoli cells and germ cells are important for maintaining close physical contact between these cells as well as regulating the release of mature spermatids into the lumen. Previously, we reported that Sertoli cell injury in rodents after mono-(2-ethylhexyl) phthalate (MEHP) exposure results in the activation of matrix metalloproteinase 2 (MMP2) and increases the sensitivity of germ cells to undergo apoptosis. A disruption in the physical association between Sertoli cells and germ cells and premature loss of germ cells from the seminiferous epithelium has been widely described after phthalate treatment. In this study, we investigate the functional participation of MMP2 in the mechanism underlying MEHP-induced disruption of junction complexes and the resultant loss of germ cells. Exposure of C57BL/6J mice to MEHP (1 g/kg, oral gavage) decreased the expression of occludin in the tight junctions between Sertoli cells and caused gaps between adjacent Sertoli cells as observed by transmission electron microscopy. A reduced expression of laminin-gamma3 and beta1-integrin in apical ectoplasmic specializations between Sertoli cells and germ cells in a time-dependent manner was also observed. Treatment with specific MMP2 inhibitors (TIMP2 and SB-3CT) both in vitro and in vivo significantly suppressed MEHP-induced germ cell sloughing and changes in the expression of these junctional proteins, indicating that MMP-2 plays a primary role in this process. Furthermore, the detachment of germ cells from Sertoli cells appears to be independent of the apoptotic signaling process since MEHP-induced germ cell detachment from Sertoli cells could not be prevented by the addition of a pan-caspase inhibitor (z-VAD-FMK).

Curcumin has been reported to exhibit anti-invasive and/or antimetastatic activities, but the mechanism remains unclear. In this study, microarray analysis of gene expression profiles were used to characterize the anti-invasive mechanisms of curcumin in highly invasive lung adenocarcinoma cells (CL1-5). Results showed that curcumin significantly reduces the invasive capacity of CL1-5 cells in a concentration range far below its levels of cytotoxicity (20 M) and that this anti-invasive effect was concentration dependent (10.17 Ϯ 0.76 ϫ 10 3 cells at 0 M; 5.67 Ϯ 1.53 ϫ 10 3 cells at 1 M; 2.67 Ϯ 0.58 ϫ 10 3 cells at 5 M; 1.15 Ϯ 1.03 ϫ 10 3 cells at 10 M; P Ͻ 0.05) in the Transwell cell culture chamber assay. Using microarray analysis, 81 genes were down-regulated and 71 genes were up-regulated after curcumin treatment. Below sublethal concentrations of curcumin (10 M), several invasion-related genes were suppressed, including matrix metalloproteinase 14 (MMP14; 0.65-fold), neuronal cell adhesion molecule (0.54-fold), and integrins ␣6 (0.67-fold) and ␤4 (0.63-fold). In addition, several heatshock proteins (Hsp) [Hsp27 (2.78-fold), Hsp70 (3.75-fold), and Hsp40-like protein (3.21-fold)] were induced by curcumin. Realtime quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry confirmed these results in both RNA and protein levels. Curcumin (1 to 10 M) reduced the MMP14 expression in both mRNA and protein levels and also inhibited the activity of MMP2, the down-stream gelatinase of MMP14, by gelatin zymographic analysis. Based on these data, it can be concluded that curcumin might be an effective antimetastatic agent with a mechanism of anti-invasion via the regulation of certain gene expressions.Curcumin, or diferuloylmethane, is a major chemical component of turmeric (Curcuma longa) and is used as a spice to give a specific flavor and yellow color to curry. It is also used as a cosmetic and in some medical preparations (Govindarajan, 1980). Curcumin has been shown to display anticarcinogenic properties in animals, as indicated by its ability to inhibit phorbol ester-induced skin tumors in a mouse model system (Huang et al., 1988). In addition to its anticarcinogenic effect, curcumin is also shown to exhibit anti-inflammatory, antiproliferative, antiangiogenic, and antioxidant properties . These effects of curcumin may be mediated by its inhibitory effect on a host of cell-signaling factors, including AP-1 transcription factor, c-Myc, Egr-1, NF-B, protein kinase C, epidermal growth factor receptor tyrosine kinase, c-Jun N-terminal kinase, protein tyrosine kinases, protein serine/threonine kinases, and IB kinase (Huang et al., 1988;Hong et al., 1999;Lin et al., 2000). In our previous study, it was also found that curcumin could inhibit cell cycle progression and induce cell apoptosis by regulating the gene expression of c-myc and bcl-2 (Chen and Huang, 1998).

The Fas/FasL signaling pathway has previously been demonstrated to be critical for triggering germ cell apoptosis in response to mono-(2-ethylhexyl)phthalate (

HighlightPhytoplasma effector SAP11 modulates plant volatile organic compound emissions by suppressing the expression of NbOMT1, which encodes an O-methyltransferase required for the biosynthesis of 3-isobutyl-2-methoxypyrazine.