The mechanisms of peroxisomal biogenesis remain incompletely understood, specially regarding the role of the endoplasmic reticulum (ER) in human cells, where genetic disorders of peroxisome biogenesis lead to Zellweger syndrome (ZS). The Pex3p peroxisomal membrane protein (PMP) required for early steps of peroxisome biogenesis has been detected in the ER in yeast but not in mammalian cells. Here, we show that Pex3p-GFP expressed in a new ZS cell line (MR), which lacks peroxisomes due to a mutation in the PEX3 gene, localizes first in the ER and subsequently in newly formed peroxisomes. Pex3p bearing an artificial N-glycosylation site shows an electrophoretic shift indicative of ER targeting while en route to preformed peroxisomes in normal fibroblast. A signal peptide that forces its entry into the ER does not eliminate its capability to drive peroxisome biogenesis in ZS cells. Thus, Pex3p is able to drive peroxisome biogenesis from the ER and its ER pathway is not privative of ZS cells. Cross-expression experiments of Pex3p in GM623 cells lacking Pex16p or Pex16p in MR cells lacking Pex3p, showed evidence that Pex3p requires Pex16p for ER location but is dispensable for the ER location of Pex16p. These results indicate that Pex3p follows the ER-to-peroxisomal route in mammalian cells and provides new clues to understand its function.

Following infection withThe female reproductive tract is an immunologically unique site which must respond to a diverse array of sexually transmitted pathogens and must also be tolerant to allogeneic sperm and to conceptuses. Pelvic inflammatory disease (PID) is an acute clinical syndrome associated with the ascending spread of microorganisms through the female reproductive tract (80). PID encompasses a multitude of inflammatory conditions of the upper reproductive tract organs, with the majority of proven cases of PID being caused by Chlamydia trachomatis and Neisseria gonorrhoeae (gonococcus) (32), and coinfection with both pathogens is common.Neisseria gonorrhoeae is the etiologic agent of gonorrhea, and the organism infects the mucosal epithelia of the male urethra and the lower genital tracts (vagina/cervix) of women. Localized infection with gonococci leads to a mucopurulent cervicitis in women, but it is also frequently asymptomatic. However, in approximately 10 to 25% (7,26,70) of untreated individuals, infection may ascend into the upper reproductive tract to involve the endometrium, ovaries, myometrium, parametrium, and Fallopian tubes (FT) (32, 46). The host response to this ascending infection is manifested as endometritis, pelvic (tubal or ovarian) peritonitis, tubal abscess, and salpingitis in the FT, and all of these inflammatory conditions encompass the clinical syndrome of PID. Long-term sequelae that develop in individuals presenting with PID, such as chronic pelvic pain, tubal damage, and ectopic pregnancy (7,26,70), are recognized as important public health problems worldwide (32,46).The FT is essentially a muscular organ whose lumen is lined by columnar ciliated cells and secretory cells with microvilli (68), and it plays a critical role in mammalian reproduction, functioning as a channel and storage organ for spermatozoa, a collecting vessel for oocytes released from the ovaries, the site of fertilization and zygote formation, and a means for transporting the early embryo to the uterus (54, 68). It is recognized that salpingitis induced by gonococcal infection causes significant tissue damage in the FT, which is resolved by a process of repair by infiltrating fibroblasts that leads to scarring. These events cause functional impairment of the tubes and irreversible infertility (80). However, little is known of the molecular mechanisms involved in the early stages of infection of the FT by ascending gonococci that initiate the inflammatory response. Studying the pathogenesis of gonococcus-induced salpingitis has relied on the use of ex vivo human FT organ tube

Infection of the Fallopian tubes (FT) byNeisseria gonorrhoeae can lead to acute salpingitis, an inflammatory condition, which is a major cause of infertility. Challenge of explants of human FT with gonococci induced mRNA expression and protein secretion for the proinflammatory cytokines interleukin (IL)-1␣, IL-1␤, and tumor necrosis factor alpha (TNF-␣) but not for granulocyte-macrophage colony-stimulating factor. In contrast, FT expression of IL-6 and of the cytokine receptors IL-6R, TNF receptor I (TNF-RI), and TNF-RII was constitutive and was not increased by gonococcal challenge. These studies suggest that several proinflammatory cytokines are likely to contribute to the cell and tissue damage observed in gonococcal salpingitis.

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Vertebrate reproduction is dependent on the operation of a central signal generator that directs the episodic release of gonadotropin-releasing hormone, a neuropeptide that stimulates secretion of the pituitary gonadotropic hormones and, thereby, controls gonadal function. The electrophysiological correlates of this pulse generator are characterized by abrupt increases in hypothalamic multiunit electrical activity (MUA voDleys) invariably associated with the initiation of secretory episodes of luteinizing hormone. Using cluster analysis, we extracted single units from the multiunit signals recorded from the mediobasal hypothalamus of four intact and four ovariectomized rhesus monkeys. Of the 40 individual units identified in this manner, 24 increased their frequency with the MUA volleys. The onset and termination of these single-unit bursts occurred coincidently with those of the MUA volleys in both intact and ovariectomized animals, indicating that the longer duration of the MUA voDleys characteristic of the gonadectomized animals was due not to the sequential activation of different units but to the longer bursts of the individual cels. Four other units showed decreases in firing rate during the MUA volleys, while the frequency of the remainder did not change. All the examined units were active during the intervals between the volleys of electrical activity. The results indicate that the MUA voDleys associated with the activity of the gonadotropin-releasing hormone pulse generator represent the simultaneous increase in firing rate of some individual hypothalamic neurons and the decrease in the frequency of others.The rhythmic, pulsatile secretion of the pituitary gonadotropic hormones, described in every vertebrate studied in this regard, is governed by a hypothalamic "clock" generally referred to as the gonadotropin-releasing hormone (GnRH) pulse generator. The operation of this signal generator at an appropriate frequency for the species is an absolute requirement for normal gonadal function (see ref. 1 for review).In the rhesus monkey, this central signal generator fires approximately once an hour and has been localized in the region ofthe arcuate nucleus (2), but -its cellular basis remains in doubt (3). Abrupt increases in multiunit activity (MUA volleys) that are invariably synchronous with the initiation of luteinizing hormone pulses measured in peripheral blood (Fig. 1) have been recorded from this area in the rhesus monkey (4), rat (5), and goat (6). The unitary association between luteinizing hormone pulses and these electrical signals has been observed in a variety of experimental circumstances (4, 7-11) as well as during the normal menstrual cycle (12) and has permitted the conclusion that these MUA volleys are the electrophysiological manifestations of GnRH pulse generator activity.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact....