Comparison of the inhibitory effects of interferons-alpha and -gamma on testosterone production in porcine Leydig cell culture

DNA damage contributes to transcriptional and immunological dysregulation of testicular cells during Chlamydia infection

Chlamydia is the most commonly reported sexually transmitted bacterial infection, with 127 million notifications worldwide each year. Both males and females are susceptible to the pathological impacts on fertility that Chlamydia infections can induce. However, male chlamydial infections, particularly within the upper reproductive tract, including the testis, are not well characterized. In this study, using mouse testicular cell lines, we examined the impact of infection on testicular cell lineage transcriptomes and potential mechanisms for this impact. The somatic cell lineages exhibited significantly fragmented genomes during infection. Likely resulting from this, each of the Leydig, Sertoli and germ cell lineages experienced extensive transcriptional dysregulation, leading to significant changes in cellular biological pathways, including interferon and germ-Sertoli cell signalling. The cell lineages, as well as isolated spermatozoa from infected mice, also contained globally hypomethylated DNA. Cumulatively, the DNA damage and epigenetic-mediated transcriptional dysregulation observed within testicular cells during chlamydial infection could result in the production of spermatozoa with abnormal epigenomes, resulting in previously observed subfertility in infected animals and congenital defects in their offspring.

Excess type I interferon signaling in the mouse seminiferous tubules leads to germ cell loss and sterility

Type I (α and β) interferons (IFNs) elicit antiproliferative and antiviral activities via the surface receptor IFNAR. Serendipitous observations in transgenic mice in 1988 strongly suggested that IFNα/β overexpression in the testis disrupts spermatogenesis. Here, we compare a new mouse strain transgenic for IFNβ (Tg10) and a sister strain lacking the IFNAR1 subunit of IFNAR (Tg10-Ifnar1(-/-)), both strains expressing the transgene in the testis. The main source of IFNβ RNA was the spermatid population. Importantly, the Tg10 mice, but not the double mutant Tg10-Ifnar1(-/-), showed altered spermatogenesis. The first IFNAR-dependent histological alteration was a higher apoptosis index in all germ cell categories apart from non-dividing spermatogonia. This occurred 3 weeks after the onset of IFNβ production at postnatal day 20 and in the absence of somatic cell defects in terms of cell number, expression of specific cell markers, and hormonal activities. Several known interferon-stimulated genes were up-regulated in Tg10 Sertoli cells and prepachytene germ cells but not in pachytene spermatocytes and spermatids. In concordance with this, pachytene spermatocytes and spermatids isolated from wild-type testes did not display measurable amounts of IFNAR1 and phosphorylated STAT1 upon IFNβ challenge in vitro, suggesting hyporesponsiveness of these cell types to IFN. At day 60, Tg10 males were sterile, and Sertoli cells showed increased amounts of anti-Mullerian hormone and decreased production of inhibin B, both probably attributable to the massive germ cell loss. Type I interferon signaling may lead to idiopathic infertilities by affecting the interplay between germ cells and Sertoli cells.

Possible modulation by male sex hormone of Th1/Th2 function in protection against Plasmodium chabaudi chabaudi AS infection in mice

Zhang, Z.-H., Chen, L., Saito, S., Kanagawa, O., and Sendo, F. 2000. Possible modulation by male sex hormone of Th1/Th2 function in protection against Plasmodium chabaudi chabaudi AS infection in mice. Experimental Parasitology 96, 121-129. We examined the mortality, survival time, and parasitemia in interferon gamma receptor (IFN-gamma R)-deficient (IFN-gamma R(-/-)) and IL-4-deficient (IL-4(-/-)) mice infected with Plasmodium chabaudi AS and compared them with the wild type counterparts (IFN-gamma R(+/+) and IL-4(+/+), respectively). (1) Mortality was higher and survival time was shorter in males of both IFN-gamma R(-/-) and IL-4(-/-) mice infected with P. chabaudi AS, compared with their wild type counterparts, whereas such a difference was not observed in female mice. (2) These differences between males and females were not observed when male mice were castrated; however, female castration had no effect on the data. (3) The rate of parasitemia in both male and female IFN-gamma R(-/-) and IL-4(-/-) mice was higher at some points during the observation than in the wild type counterparts. (4) These results on susceptibility vs resistance to P. chabaudi AS infection can be explained partially by the levels of expression of Th1/Th2 cytokine and chemokine mRNAs in the spleen cells of the infected mice. These results suggest that male sex hormones modulate the function of Th1/Th2 cells and that these T cells counteract the activity of these hormones in protection against P. chabaudi AS infection in mice.

Effects of adjuvant interferon-alpha low-dose therapy in melanoma patients on serum inhibin B

Because the primary aim of adjuvant therapy for melanoma is not curative, all the possible aspects of quality of life have to be considered. One aspect of increasing importance is fertility. The effect of adjuvant interferon alpha-therapy for malignant melanoma on male fertility has not been systematically investigated. In the present study, twelve male patients with primary cutaneous melanoma (pT3, 4; N0; M0) who were taking adjuvant low-dose interferon alpha2b (3 x 3 mio U/week) for one year were included. Inhibin B--an established marker of male fertility-was measured with an immunosorbent assay before and after one year of interferon alpha-therapy to investigate whether this treatment has any influence on fertility. The results were compared with those from normal controls (n=40). The mean serum inhibin B concentration in melanoma patients before interferon therapy was 225.4 +/- 112.5 pg/mL; after treatment the level was 229.6 +/- 82.0 pg/mL. This difference was not statistically significant (p>0.05). The serum inhibin B concentration in controls was 201.5 +/- 17.1 pg/mL, which was not statistically different from either untreated or interferon-treated melanoma patients (p>0.05). We conclude that low-dose interferon alpha does not have a significant (negative) effect on inhibin B or male fertility.

Role of cytokines in testicular function

Inflammatory disease has been established to affect male reproductive function and fertility. Relevant inflammatory diseases include general and chronic infectious diseases as well as localized acute or chronic infections of the male genitourinary tract. Male accessory gland infections account for almost 15% of all cases of male infertility seen in infertility clinics while fertility usually is not a clinical objective among patients with acute systemic infections such as Gram-negative sepsis. Infections of the male accessory glands frequently are associated with increased counts of white blood cells in semen and elevated levels of proinflammatory cytokines in semen and the testis. There is a mounting body of evidence that demonstrates the importance of cytokines and chemokines in the regulation of testicular and glandular function during pathophysiological states as well as under normal physiological conditions when cytokines act as growth and differentiation factors. The purpose of this review is to examine the role of cytokines in the regulation of steroidogenesis and spermatogenesis in the testis under physiological and pathophysiological conditions and considers clinical investigations that help to improve the evaluation and treatment of male infertility.

Expression of interferons-alpha and -gamma in testicular interstitial tissue and spermatogonia of the rat

The testis is divided into two compartments: the seminiferous tubules and the interstitial tissue. The latter essentially consists of the blood and lymphatic vessels, testosterone-producing Leydig cells, and testicular macrophages. In the exploration of the testicular antiviral defense system, we initially searched for interferon (IFN) production by the seminiferous tubule cells. The site of virus entry into the testis is probably the interstitial compartment; thus, it is important to know whether and how the cells in this compartment are protected against viral infection. In addition, as germ cell precursors (spermatogonia) are only partially protected by the blood-testis barrier, it was important to explore the antiviral capability of these cells. In this study we searched for IFN production by Leydig cells, testicular macrophages, and spermatogonia after exposure to Sendai virus. We also investigated the effect of viral exposure on testosterone production by Leydig cells. Our results show that spermatogonia do not constitutively express IFNs and give a very poor response to the virus. In contrast, testicular macrophages constitutively produced type I IFNs, and this production was markedly stimulated by Sendai virus. Leydig cells produced twice as much type I IFNs as testicular macrophages after viral exposure, and they were the only cells producing both IFNalpha and -gamma, with these IFNs being dramatically induced/ increased in response to exposure to the virus. Furthermore, incubation of Leydig cells with the Sendai virus stimulated testosterone production. In conclusion, this study further establishes the topography of IFN expression within the testis. This allows us to hypothesize that the potential antiviral system represented by Leydig cells and, to a lesser extent, by macrophages plays a key role in protecting both androgen production and spermatogenesis.

Effect of interferon alpha on high serum androgen concentrations in HIV positive men with Kaposi's sarcoma

AIM

To measure serum androgen concentrations in men with HIV related Kaposi's sarcoma (KS) who had been treated with recombinant interferon (IFN) alpha-2a to determine the role of androgens on the development of KS lesions.

METHODS

32 men with HIV related KS who had been treated with IFN were studied: 24 men in complete KS remission and eight not in remission. Serum androgen concentrations were determined before, during, and after IFN treatment and correlated with clinical remission.

RESULTS

All patients in complete KS remission had lower serum androgen concentrations following IFN treatment: -51% for dehydroepiandrosterone (DHEA) (p < 0.0001); -38% for DHEA sulphate (p < 0.002);-39% for androstenedione (p < 0.002); and -44% for testosterone (p < 0.007). These decreases brought the serum concentrations to about normal levels. However, IFN had varying effects on serum androgen concentrations in the men not in remission: a small decrease, a large increase in one androgen, or no change in serum androgens.

CONCLUSIONS

The association between serum androgen levels and the progression or remission of HIV associated KS suggests that androgens affect the development of KS lesions. A clear understanding of the changes in the androgen environment may provide a sound basis for the development of new therapeutic strategies.

The effects of cytokines on human chorionic gonadotropin (hCG) production by a trophoblast cell line

The present study was conducted to investigate the effects of cytokines on human chorionic gonadotropin (hCG) and its alpha- and beta-subunit release as well as protein synthesis in a trophoblast cell line. The human choriocarcinoma cell line, Jar, was used as a trophoblast model. Jar cells were incubated for 24 h with varying concentrations (5 x 10(-4)-40 micrograms/ml) of the following cytokines: Il-1, Il-2, Il-3, Il-4, Il-5, Il-6, IFN-gamma, tumor necrosis factor (TNF)-alpha, M-CSF and GM-CSF. Supernatants were assayed for hCG and its alpha- and beta-subunits by immunoradiometric methods. Cytotoxic effects were assessed by trypan blue staining. Protein synthesis was measured by [3H]leucine incorporation. The cytokines Il-1 and TNF-alpha significantly stimulated hCG release. The other cytokines had no significant effect on hCG production. Protein synthesis by the Jar cells was not significantly affected by either Il-1 or TNF-alpha. However, IFN-gamma (40 micrograms/ml) significantly suppressed protein synthesis by the Jar cells. Trophoblast viability in the presence of TNF-alpha (10 micrograms/ml) and IFN-gamma (40 micrograms/ml) was only 40% and 50%, respectively. These results suggest that cytokines may be important regulators of trophoblast function. Il-I appears to have a stimulatory effect on trophoblast hCG release, while TNF-alpha and IFN-gamma appear to have cytotoxic effects on trophoblast cells.

Effect of bovine interferon on acute changes in body temperature and serum progesterone concentrations in heifers

Bovine interferon-alpha I1 has extensive sequence and functional homology with the antiluteolytic protein, bovine trophoblast protein-1. Because of the possible use of interferon-alpha I1 as a drug that supplements embryonic secretion of bovine trophoblast protein-1, interferon-alpha I1 was tested for other biological actions that might affect its usefulness as a fertility-enhancing treatment. Experiments were performed to evaluate whether interferon-alpha I1 causes hyperthermia and an acute depression in circulating concentrations of progesterone. In four experiments, intramuscular administration of interferon-alpha I1 (range 1.25 to 20 mg) caused hyperthermia; average peak body temperatures of 40 to 40.4 degrees C occurred 2.5 to 6 h after injection. Temperatures returned to baseline 12 to 16 h later. The rise in rectal temperature could be reduced, but not totally alleviated, with concomitant administration of an inhibitor of prostaglandin synthesis. The maximal hyperthermic response was similar when interferon-alpha I1 was delivered via osmotic minipumps or through a series of intramuscular injections. The hyperthermic response decreased with repeated daily exposure to interferon-alpha I1. The increase in rectal temperatures was associated temporally with a decrease in serum progesterone. Effects of interferon-alpha I1 on body temperature and circulating progesterone could possibly limit its effectiveness in enhancing fertility.

Interferon-gamma modulates melatonin production in rat pineal glands in organ culture

The effect of interferon-gamma (IFN-gamma) on melatonin production was determined in rat pineal glands in organ culture. IFN-gamma enhanced the production of melatonin in the glands incubated with either 10 nM or 1,000 nM isoproterenol (ISO, a beta-adrenergic receptor agonist) but decreased the 100 nM ISO response. The enhanced melatonin production was accompanied by either unchanged or a lower level of N-acetyltransferase (NAT) activity, whereas the suppression was accompanied by a reduced NAT activity. IFN-gamma did not change the activity of the enzyme hydroxyindole-O-methyltransferase (HIOMT) in the ISO-stimulated pineal glands. The results indicate that IFN-gamma has a dual action on the pineal gland: One is to increase melatonin production through yet unknown mechanisms, and the other is to suppress NAT activity. These results also suggest that the pineal gland, under physiological stimulation, is modulated by IFN-gamma to increase melatonin production. A hypothetical model is proposed to explain the delicate regulation of pineal function by the immune system.

Changes in indole metabolism in organ cultured rat pineal glands induced by interferon-gamma

The purpose of this study was to test the effects of recombinant rat interferon-gamma (IFN-gamma) on rat pineal function in organ culture. The glands were pre-incubated with IFN-gamma (50, 100, and 1,000 antiviral units/ml) for two hours, followed by a stimulation with isoproterenol (ISO, 10(-6) M) (in the presence of IFN-gamma) for an additional three hours. The effect of IFN-gamma alone on the pineal function was also tested by adding another group incubated with IFN-gamma (1,000 antiviral units/ml) without ISO stimulation. The following parameters were estimated at the end of the incubation: the activities of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), the levels of melatonin, 5-hydroxytryptophan (5HTP), 5-hydroxytryptamine (5HT), and 5-hydroxyindole acetic acid (5HIAA), and the 5HT/5HIAA ratio. IFN-gamma had no effect on either NAT or HIOMT activities in the pineal glands. At 50 units/ml, IFN-gamma increased the melatonin content over the ISO-stimulated level in the pineal but not in the media. IFN-gamma alone, at 1,000 units/ml, also increased the melatonin content significantly over the control level. The levels of 5HTP and 5HIAA were significantly suppressed by IFN-gamma, either alone or in combination with ISO. The level of 5HT was not altered by any of the treatments. The 5HT/5HIAA ratio was significantly increased by IFN-gamma, either when given alone or when given in combination with ISO. The results suggest that IFN-gamma enhances melatonin production in the pineal gland by suppressing the oxidative deamination of 5HT to 5HIAA and shunting the biosynthetic pathway toward melatonin production.