Synthesis of highly functionalised spiro-indoles by a halogen atom transfer radical cyclization.

The halogen atom transfer radical cyclization (HATRC) has been evaluated on N-(indolylmethyl)trichloroacetamides under Cu(I)Cl catalysis using nitrogen containing ligands. The ring closure leads to the formation of 3,3-spiro-3H-indoles in moderate to good yields by a 5-exo-mechanism. Derivatives with an N-electron withdrawing substituent also lead to a 5-exo-trig and not to a 6-endo-trig cyclization.

Response of matrix metalloproteinases and tissue inhibitors of metalloproteinases messenger ribonucleic acids to ovarian steroids in human endometrial explants mimics their gene- and phase-specific differential control in vivo.

CONTEXT: Cyclic remodeling and breakdown of the extracellular matrix, a unique feature of the human endometrium, depends on matrix metalloproteinases (MMPs). These enzymes are globally controlled by estradiol and progesterone or their withdrawal, but various MMPs and their tissue inhibitors (TIMPs) show distinct responses. OBJECTIVE AND DESIGN: To clarify the role of ovarian steroids in the differential regulation of MMP-1, MMP-3, MMP-7, MMP-8, MMP-10, TIMP-1, TIMP-2, and TIMP-3 mRNAs, we compared their variations in the cycling endometrium in vivo with their response to hormone addition or withdrawal in corresponding explants. RESULTS: Different patterns were identified in vivo according to the time frame (secretory vs. perimenstrual increase), sharpness (peak vs. progressive increase or decrease), and magnitude of the changes. In vivo ratios between early/midsecretory and perimenstrual phases ranged from more than 1000 (MMP-1, MMP-3, and MMP-10) to less than 10 (TIMPs). Differential response to ovarian steroids of the various MMPs and TIMPs mRNAs tested in cultured explants matched the same ranking and varied according to the phase at sampling. Remarkably, ovarian steroids repressed MMPs and TIMP-1 and TIMP-2 but, in secretory explants, increased TIMP-3 mRNA. Finally, in situ hybridization evidenced the major contribution of fibroblasts to the increase in MMP-8 mRNA at menstruation or in explants cultured without hormones. CONCLUSIONS: Both phase- and gene-specific modulators finely tune in space, time, and amplitude the global control of MMPs and TIMPs mRNAs by estradiol and progesterone in the cycling human endometrium.

Regulation of matrix metalloproteinase-9/gelatinase B expression and activation by ovarian steroids and LEFTY-A/endometrial bleeding-associated factor in the human endometrium.

Various matrix metalloproteinases (MMPs) participate in the menstrual breakdown of the human endometrium. MMP-9/gelatinase B is proposed as a major factor because it degrades many extracellular matrix constituents, including in the vasculature. Although globally under ovarian steroids control, endometrial MMP-9 seems expressed differently than other MMPs, and conflicting publications prevent a clear understanding of its regulation. We therefore quantified MMP-9 expression in the cycling human endometrium, defined its localization, and analyzed its regulation by estradiol and progesterone and by LEFTY-A/endometrial bleeding-associated factor in explant cultures. In fresh tissues, a major increase in MMP-9 mRNA expression occurred at menstruation, after a larger increase in LEFTY-A mRNA. MMP-9 was immunodetected in all cell types throughout the cycle, especially in foci of stromal cells during menstruation. MMP-9 synthesis by these cells was confirmed in cultured explants. In proliferative explants, ovarian steroids slightly decreased MMP-9 mRNA. They had no consistent effect on MMP-9 release in culture medium but strongly inhibited proMMP-9 activation. Addition of recombinant LEFTY-A to explants induced MMP-9 in most samples, a response prevented by ovarian steroids. We propose that endometrial MMP-9 activity is overall controlled by the ovarian steroids and locally adjusted through a network of modulators, including LEFTY-A.

Low density lipoprotein receptor-related protein mediates endocytic clearance of pro-MMP-2.TIMP-2 complex through a thrombospondin-independent mechanism.

The low density lipoprotein receptor-related protein (LRP) mediates the endocytic clearance of various proteinases and proteinase.inhibitor complexes, including thrombospondin (TSP)-dependent endocytosis of matrix metalloproteinase (MMP)-2 (or gelatinase A), a key effector of extracellular matrix remodeling and cancer progression. However, the zymogen of MMP-2 (pro-MMP-2) mostly occurs in tissues as a complex with the tissue inhibitor of MMPs (TIMP-2). Here we show that clearance of the pro-MMP-2.TIMP-2 complex is also mediated by LRP, because addition of receptor-associated protein (RAP), a natural LRP ligand antagonist, inhibited endocytosis and lysosomal degradation of (125)I-pro-MMP-2.TIMP-2. Both TIMP-2 and the pro-MMP-2 collagen-binding domain independently competed for endocytosis of (125)I-pro-MMP-2.TIMP-2 complex. Surface plasmon resonance studies indicated that pro-MMP-2, TIMP-2, and pro-MMP-2.TIMP-2 directly interact with LRP in the absence of TSP. LRP-mediated endocytic clearance of (125)I-pro-MMP-2 was inhibited by anti-TSP antibodies and accelerated upon complexing with TSP-1, but these treatments had no effect on (125)I-pro-MMP-2.TIMP-2 uptake. This implies that mechanisms of clearance by LRP of pro-MMP-2 and pro-MMP-2.TIMP-2 complex are different. Interestingly, RAP did not inhibit binding of (125)I-pro-MMP-2.TIMP-2 to the cell surface. We conclude that clearance of pro-MMP-2.TIMP-2 complex is a TSP-independent two-step process, involving (i) initial binding to the cell membrane in a RAP-insensitive manner and (ii) subsequent LRP-dependent (RAP-sensitive) internalization and degradation.

Focal expression and final activity of matrix metalloproteinases may explain irregular dysfunctional endometrial bleeding.

Irregular dysfunctional bleeding of the endometrium (ie, metrorrhagia without organic lesion) is common in women, whether treated or not with ovarian hormones. Several matrix metalloproteinases (MMPs) become normally expressed and/or activated at menstruation and cause extracellular matrix breakdown. We therefore explored whether episodes of irregular dysfunctional bleeding could be associated with untimely MMP activity. By histology, foci of stromal breakdown were exclusively found in the endometrium of metrorrhagic women at bleeding. In these foci, 1) expression of estrogen receptor-alpha and progesterone receptor was altered; 2) collagenase-1 (MMP-1), stromelysin-1 (MMP-3), and gelatinase B (MMP-9) became detected in stromal cells, together with MMP-9 in neutrophils; and 3) gelatinase A (MMP-2) was more expressed and immunolocalized at the membrane of stromal cells. By biochemistry, endometrial lysates from nonbleeding metrorrhagic patients contained more latent and active MMP-2 and -9 than age-matched controls; at bleeding, collagenase activity, MMP-9, and active MMP-2 were strikingly increased whereas tissue inhibitor of metalloproteinases-1 (TIMP-1) was considerably decreased. As a functional assay, in situ gelatin zymography revealed large areas of gelatinolytic activity only in endometrium of bleeding patients. Altogether, these results strongly suggest that inappropriate focal expression and activation of several MMPs, combined with decreased inhibition, trigger irregular dysfunctional endometrial bleeding.

Regulation and function of LEFTY-A/EBAF in the human endometrium. mRNA expression during the menstrual cycle, control by progesterone, and effect on matrix metalloprotineases.

The human endometrium is a unique tissue that is periodically shed during menstruation. Although overall triggered by ovarian steroids withdrawal, menstrual induction of matrix metalloproteinases (MMPs) and resulting tissue breakdown are focal responses, pointing to additional local modulators. LEFTY-A, a novel member of the transforming growth factor-beta family identified originally as an endometrial bleeding-associated factor (EBAF), is a candidate for this local control. We measured LEFTY-A and beta-ACTIN mRNA concentration during the menstrual cycle in vivo and found that their ratio was dramatically ( approximately 100-fold) increased at the perimenstrual phase. A similar increase was seen when proliferative explants were cultured for 24 h in the absence of ovarian steroids; this was followed by spontaneous production of proMMP-1, -3, and -9. Both responses were inhibited by progesterone. Moreover, addition of recombinant LEFTY-A to proliferative explants was sufficient to stimulate the expression of proMMP-3 and -7; this response was also blocked by ovarian steroids. Collectively, these data indicate that LEFTY-A may provide a crucial signal for endometrial breakdown and bleeding by triggering expression of several MMPs. Progesterone appears to exert a dual block, upstream by inhibiting LEFTY-A expression and downstream by suppressing its stimulatory effect on MMPs.

Circulating ovarian steroids and endometrial matrix metalloproteinases (MMPs).

Recent studies strongly suggest that matrix metalloproteinases (MMPs) play a key role in the initiation of menstrual bleeding in the human endometrium upon the fall of ovarian steroid serum concentrations by inducing the degradation of the extracellular matrix of this mucosa. MMPs are also involved in abnormal endometrial bleeding and have been identified in endometriotic foci. In all cases, they are associated with areas of extracellular matrix breakdown. This paper reviews the literature on the regulation by estradiol and progesterone of the expression and activation of MMPs, and of the expression of their tissue inhibitors (TIMPs), (i) in the endometrium in situ during normal cycle, (ii) during artificial cycles in spayed monkeys, and (iii) in cultures of endometrial explants or purified cells. Whereas progesterone consistently decreases the activity of endometrial MMPs, its effects vary in intensity, duration, and pattern between MMPs as well as among experimental systems. The contribution and limitations of the various investigations are therefore discussed. The focal heterogeneity points to additional local controls of the expression and activation of MMPs in human endometrium, acting beyond the general inhibitory role of progesterone, for example, by cytokines. Focal changes in type or abundance of sex steroid receptors also could be responsible for spatial variation in the expression of MMPs in the endometrium and endometriotic lesions.