Polyamines control human chorionic gonadotropin production in the JEG-3 choriocarcinoma cell

Post Orgasmic Illness Syndrome (POIS) and Delayed Onset Muscle Soreness (DOMS): Do They Have Anything in Common?

Post orgasmic illness syndrome is a rare, mysterious condition with an unknown pathomechanism and uncertain treatment. The symptoms of post orgasmic illness syndrome last about 2–7 days after an ejaculation. The current hypothesis proposes that the primary injury in post orgasmic illness syndrome is an acute compression proprioceptive axonopathy in the muscle spindle, as is suspected in delayed onset muscle soreness. The terminal arbor degeneration-like lesion of delayed onset muscle soreness is theorized to be an acute stress response energy-depleted dysfunctional mitochondria-induced impairment of Piezo2 channels and glutamate vesicular release. The recurring symptoms of post orgasmic illness syndrome after each ejaculation are suggested to be analogous to the repeated bout effect of delayed onset muscle soreness. However, there are differences in the pathomechanism, mostly attributed to the extent of secondary tissue damage and to the extent of spermidine depletion. The spermidine depletion-induced differences are as follows: modulation of the acute stress response, flu-like symptoms, opioid-like withdrawal and enhanced deregulation of the autonomic nervous system. The longitudinal dimension of delayed onset muscle soreness, in the form of post orgasmic illness syndrome and the repeated bout effect, have cognitive and memory consequences, since the primary injury is learning and memory-related.

Adverse placental effect of formic acid on hCG secretion is mitigated by folic acid

AIMS

Formic acid has recently been detected in maternal blood and umbilical cord blood of infants born to alcohol abusing mothers. This toxic metabolite of methanol requires folate for detoxification. We hypothesized that formic acid produced in the maternal circulation will transfer across the placenta and will be toxic to the placenta. Our objectives were, first, to determine whether formic acid transfers across the human placenta and whether it is toxic to the placenta and second, to determine whether folate can decrease transplacental transfer of formic acid and mitigate toxicity.

METHODS

Dual perfusion of a single placental lobule ex vivo was used to characterize the transfer of formic acid across the placenta. After a 1-h control period, formic acid (2 mM) was introduced into the maternal circulation with (n = 4) or without folate (1 µM) (n = 4) and was allowed to equilibrate for 3 h.

RESULTS

Formic acid transferred rapidly from the maternal to the fetal circulation, and transfer was not altered with the addition of folate. Compared with the control period, there was a significant decrease in hCG secretion (P = 0.03) after addition of formic acid. The addition of folic acid to the perfusate mitigated the decrease in hCG.

CONCLUSIONS

Formic acid rapidly transfers across the placenta and thus has the potential to be toxic to the developing fetus. Formic acid decreases hCG secretion in the placenta, which may alter steroidogenesis and differentiation of the cytotrophoblasts, and this adverse effect can be mitigated by folate.

Human placenta: a human organ for developmental toxicology research and biomonitoring

Pregnant mothers are exposed to a wide variety of foreign chemicals. This exposure is most commonly due to maternal medication, lifestyle factors, such as smoking, drug abuse, and alcohol consumption, or occupational and environmental sources. Foreign compounds may interfere with placental functions at many levels e.g. signaling, production and release of hormones and enzymes, transport of nutrients and waste products, implantation, cellular growth and maturation, and finally, at the terminal phase of placental life, i.e. delivery. Placental responses may also be due to pharmaco-/toxicodynamic responses to foreign chemicals, e.g. hypoxia. On the other hand, placental xenobiotic-metabolizing enzymes can detoxify or activate foreign chemicals, and transporters either enhance or prevent cellular accumulation and transfer across the placenta. The understanding of what xenobiotics do to the placenta and what the placenta does to the xenobiotics should provide the basis for the use of placenta as a tool to investigate and predict some aspects of developmental toxicity. This review aims to give an update of the fate and behavior of xenobiotics in the placenta from the viewpoint of xenobiotic-metabolizing enzymes and transporters. Their response levels will be described according to gestational status and methods used. The effects of foreign chemicals on placental metabolizing enzymes will be discussed. Also, interactions in the transporter protein level will be covered. The role of the placenta in contributing to developmental effects and fetotoxicity will be examined. The toxicological effects of maternal medications, smoking, and environmental exposures (dioxins, pesticides) as well as some possibilities for biomonitoring will be highlighted.

Effects of zidovudine (AZT) and dideoxyinosine (ddI) on human trophoblast cells

The anti-HIV agents AZT (zidovudine) and ddl (dideoxyinosine) are being used clinically during pregnancy. The toxicity of these agents to the fetus and placenta remains a concern because few human pregnancy exposure data are available, and pregnant rodent studies with AZT indicate increased embryonic resorptions and developmental arrest. The current study used a human choriocarcinoma cell line (JAr), which exhibits many characteristics of the early placenta, to assess the effects of a single 24 h exposure of 7.6 or 0.076 mM AZT, and the effects of a single 24 h exposure of 7.6 or 0.076 mM ddI upon cell proliferation and hormone production of human chorionic gonadotropin (hCG), estradiol (E2), and progesterone (P4). The higher concentration of AZT and ddI produced significant (P < 0.025) reductions in cell numbers and growth rate while producing significant increases in hormone production (hCG, E2, and P4). The lower concentration of AZT and ddI produced significant increases in E2 production, but no changes in cell numbers, hCG, or P4. Because placental cells require androgen precursor for E2 synthesis, exogenous androstenedione was added to confirm observations of increased estradiol synthesis after AZT or ddl exposure. These results demonstrate that single 24 h high dose exposures of AZT or ddI produce significant inhibition of cell proliferation and alterations in hormone production in this paradigm of human placental cells.

Differences in transglutaminase mRNA after polyamine depletion in two cell lines

Polyamines serve as natural substrates for the transglutaminase that catalyzes covalent cross-linking of proteins and is involved in cellular adhesion and proliferation. This study tests the hypothesis that intracellular polyamines play a role in the regulation of transglutaminase expression in rat small intestinal crypt cells (IEC-6 cell line) and human colon carcinoma cells (Caco-2 cell line). Treatment with alpha-difluoromethylornithine (DFMO; a specific inhibitor of polyamine synthesis) significantly depleted the cellular polyamines putrescine, spermidine, and spermine in both cell lines. In IEC-6 cells, polyamine depletion was associated with a decrease in the levels of transglutaminase mRNA. In Caco-2 cells, however, polyamine depletion significantly increased the levels of transglutaminase mRNA and enzyme activity. In both cell lines, ornithine decarboxylase mRNA levels increased and protooncogene c-myc mRNA decreased in the presence of DFMO. Addition of polyamines to cells treated with DFMO reversed the effect of DFMO on the levels of mRNA for these genes in both lines. There was no significant change in the stability of transglutaminase mRNA between control and DFMO-treated IEC-6 cells. In contrast, the half-life of mRNA for transglutaminase in Caco-2 cells was dramatically increased after polyamine depletion. Spermidine, when given together with DFMO, completely prevented increased half-life of transglutaminase mRNA in Caco-2 cells. These results indicate that 1) expression of transglutaminase requires polyamines in IEC-6 cells but is inhibited by these agents in Caco-2 cells, 2) polyamines modulate transglutaminase expression at the level of mRNA through different pathways in these two cell lines, and 3) posttranscriptional regulation plays a major role in the induction of transglutaminase mRNA in polyamine-deficient Caco-2 cells.

Regulation by spermine of native inward rectifier K+ channels in RBL-1 cells

Polyamines have been shown to participate in the rectification of cloned inwardly rectifying potassium channels, a class of potassium channel proteins that conducts inward current more readily than outward current. Here, basophil leukemia cells were used to determine the effects of polyamines on a native, inwardly rectifying potassium current. Rat basophil leukemia cells were cultured in the presence of two different polyamine biosynthesis inhibitors, and both the electrophysiological properties and the polyamine levels were monitored. Treatment with alpha-difluoromethylornithine, a specific ornithine decarboxylase inhibitor, resulted in no significant change of electrophysiological properties. In contrast, treatment with 5'-[(Z)-4-amino-2-butenyl]- methyl-amino-5'-deoxyadenosine (MDL73811), an inhibitor of S-adenosylmethionine decarboxylase, resulted in increased outward currents through inwardly rectifying potassium channels while intracellular putrescine was markedly increased and spermidine and spermine levels were decreased. Fluctuations of intracellular polyamine concentrations as imposed by MDL73811 were directly translated in an altered cell excitability. Based on these results we conclude that the rectification properties of native inwardly rectifying potassium channels are largely controlled by intracellular spermine.

Effects of hydroxyurea and cyclic adenosine monophosphate/protein kinase A inhibitors on the expression of the human chorionic gonadotropin alpha subunit and c-myc genes in choriocarcinoma

We have previously shown that treatment of choriocarcinoma cells with methotrexate or hydroxyurea leads to both cessation of cell growth, accompanied by repression of c-myc oncogene expression, and induction of genes associated with the placental phenotype, including both subunits of human chorionic gonadotropin (hCG) and placental alkaline phosphatase. Since the genes induced by these antimetabolites are also cyclic AMP inducible, we hypothesized that these antimetabolites may cause activation of the cyclic AMP/protein kinase A pathway, suppressing genes associated with cellular proliferation and inducing placental gene expression. Three inhibitors of the cyclic AMP/protein kinase A pathway were assayed for their ability to inhibit the induction of the human chorionic gonadotropin alpha gene by hydroxyurea, and none of these inhibitors eliminated this induction. In addition, blockade of the cyclic AMP/protein kinase A pathway did not reverse the suppression of c-myc by hydroxyurea. The results of the inhibitor studies suggest that hydroxyurea acts independently of the protein kinase A pathway to stimulate gene expression, and that suppression of c-myc is insufficient to cause the induction of the human chorionic gonadotropin alpha gene by hydroxyurea.

Modulation of growth gene expression by selective alteration of polyamines in human colon carcinoma cells

The biosynthesis of the polyamines, putrescine, spermidine and spermine, is temporally linked with expression of many growth related genes. Our previous studies have shown that generalized polyamine depletion of the human colon cancer cell line COLO 320 by 2-difluoromethylornithine is associated with decreased transcription of the c-myc, c-fos, and ornithine decarboxylase (ODC) genes. In the current study, the role of individual polyamines was further defined by the use of a specific inhibitor of spermidine synthase, S-adenosyl-1,8, diamino-3-thio-octane (AdoDATO), and a spermine analogue, N1,N12 bis(ethyl)spermine. Our data demonstrate that depletion of spermidine results in a 60-90% decrease in c-myc mRNA steady state levels. In contrast, c-fos mRNA levels are decreased only when both spermidine and spermine are diminished. Furthermore, ODC mRNA levels are increased when all polyamines are decreased by DFMO, but are unaffected by a selective reduction in intracellular spermidine levels by AdoDATO. These studies suggest that individual polyamines may have a selective role in the expression of specific growth related genes.