Cytokines and neutrophil extracellular traps in the equine endometrium: friends or foes?

Articles in International JournalsCytokines may play a dual role in the reproductive tract – either involved in physiologic processes or mediating inflammation and other pathologic processes. Physiologic secretory and angiogenic function in the equine endometrium appears to be regulated by cytokines TNFa, FasL, IFNg through their receptors. These receptors are present in glandular epithelium, and stroma cells and their mRNA expression changes throughout the estrous cycle. Besides, interleukins (IL-1a and IL-1b) and their receptors mRNA expression vary according to various degrees of endometrium inflammation (endometritis) and fibrosis (endometrosis). A novel paradigm in innate immunity and neutrophils (PMN) hyperactivation is PMN ability to cast out their DNA in response to infectious stimuli. These PMN extracellular traps (NETs) bind and kill pathogens, at the infection site. The intriguing dilemma is that even though NETs may function as a first line of defense, they also release molecules that may contribute to tissue damage. Thus, we postulate that PMN present in the endometrium at estrus, mating or infection, might form NETs, and release nucleic and cytoplasmic proteins with immunomodulatory properties. Equine PMN stimulated in vitro showed NETs formation capacity when in contact with some bacteria strains obtained from mares with endometritis, such as Streptococcus zooepidemicus, Escherichia coli and Staphylococus capitis. In this regard, even though NETs and cytokines function as an effective antimicrobial first line of defense or modulate physiologic endometrial function, respectively (friends), they may also be involved in endometrial fibrosis pathogenesis and endometrial secretory function impairment, due to enhanced NETs formation and/or a decrease on NETs degradation (foes)

Placental Origin of Prostaglandin F 2 α

In the present study, the question was addressed whether the feline placenta can synthesize prostaglandin F2 α (PGF2 α ). The PGFS protein was elevated, particularly at 2.5-3 weeks of pregnancy compared to 7-8 (P < 0.05) and 8.5-9 weeks (P < 0.001). Transcripts for PGFS were significantly upregulated at 2.5-3 weeks of pregnancy and then gradually declined towards the end of gestation (P < 0.001). Transcripts for PTGS2 were only upregulated in placentas from queens close to term (P < 0.001) compared with earlier phases. Staining of PTGS2 showed distinct positive signals in placentas obtained during the last week before labor, particularly in the strongly invading trophoblast surrounding blood vessels, and also in decidual cells. Shortly after implantation, signals for PGFS were localized in the trophoblast cells. Near term, PGFS staining was seen mainly in decidual cells. Both placental PGF2 α and plasma PGFM were elevated towards the end of pregnancy (P < 0.001) compared with earlier weeks of pregnancy. The content of PGF2 α in extracted placenta mirrored the PGFM level in plasma of pregnant females. During late gestation there is a significant increase in PGFM levels in maternal blood and of PGF2 α levels in placental tissue concomitant with an upregulation of placental PTGS2

Interleukins Affect Equine Endometrial Cell Function: Modulatory Action of Ovarian Steroids

The aim of the present study was to investigate the interaction between ovarian steroids, interleukins and prostaglandins (PG) in equine epithelial and stromal cells in vitro. In Experiment 1, cells were exposed to IL-1α (10 ng/mL), IL-1β (10 ng/mL) or IL-6 (10 ng/mL) for 24 h and cell proliferation was determined using MTT. In Experiment 2, cells were exposed to progesterone (P(4); 10(−7) M); 17-β estradiol (E(2); 10(−9) M) or P(4)+E(2) for 24 h and later medium was replaced with a fresh one treated with IL-1α, IL-1β or IL-6 (10 ng/mL, each) for 24 h. The oxytocin (OT; 10(−7) M) was used as a positive control. In Experiment 3, cells were exposed to P(4) (10(−7) M), E(2) (10(−9) M) or P(4)+E(2) for 24 h and the IL receptor mRNAs transcription was determined using Real-time PCR. Prostaglandins concentration was determined using the direct enzyme immunoassay (EIA) method. Our findings reveal a functional linking between ovarian steroids and IL-stimulated PG secretion by equine endometrial cells. This interaction could be one of the mechanisms responsible for endometrial local orchestrating events during the estrous cycle and early pregnancy

Role of tumor necrosis factor-α, interferon-γ and Fas-ligand on in vitro nitric oxide activity in the corpus luteum

Articles in International JournalsNormal reproductive function involves the expression of inflammatory mediators. Regarding the corpus luteum (CL), cytokines promote the cross-talk between immune, vascular and steroidogenic cells, among others. Moreover, TNF, IFNG and FASL were shown to regulate equine CL establishment and regression. We hypothesized that cytokines action on equine CL may be mediated by nitric oxide (NO), through the regulation of endothelial NO synthase (eNOS) expression. TNF increased eNOS mRNA level and NO metabolite (nitrite) production during CL growth. Cytokines combined action (TNF + IFNG + FASL) promoted eNOS protein upregulation in mid-CL and nitrite production in mid and late-CL. However, in late-CL, TNF alone decreased nitrite secretion. These results indicate that in equine CL, cytokines TNF, IFNG and FASL regulate NO activity, via eNOS expression modulation

Interleukins Affect Equine Endometrial Cell Function: Modulatory Action of Ovarian Steroids

The aim of the present study was to investigate the interaction between ovarian steroids, interleukins and prostaglandins (PG) in equine epithelial and stromal cells in vitro. In Experiment 1, cells were exposed to IL-1α (10 ng/mL), IL-1β (10 ng/mL) or IL-6 (10 ng/mL) for 24 h and cell proliferation was determined using MTT. In Experiment 2, cells were exposed to progesterone (P4; 10−7 M); 17-β estradiol (E2; 10−9 M) or P4+E2 for 24 h and later medium was replaced with a fresh one treated with IL-1α, IL-1β or IL-6 (10 ng/mL, each) for 24 h. The oxytocin (OT; 10−7 M) was used as a positive control. In Experiment 3, cells were exposed to P4 (10−7 M), E2 (10−9 M) or P4+E2 for 24 h and the IL receptor mRNAs transcription was determined using Real-time PCR. Prostaglandins concentration was determined using the direct enzyme immunoassay (EIA) method. Our findings reveal a functional linking between ovarian steroids and IL-stimulated PG secretion by equine endometrial cells. This interaction could be one of the mechanisms responsible for endometrial local orchestrating events during the estrous cycle and early pregnancy

LPS-challenged TNFα production, prostaglandin secretion, and TNFα/TNFRs expression in the endometrium of domestic cats in estrus or diestrus, and in cats with pyometra or receiving medroxyprogesterone acetate

Progesterone (P4) derivatives which are commonly used to block the cyclicity of domestic cats disturb the endocrine balance in the endometrium. The aims of this study were (i) to examine whether lipopolysaccharide (LPS) is responsible for enhancement of tumor necrosis factor-α (TNFα) secretion by the feline endometrial epithelial and stromal cells in vitro, (ii) to know whether immunolocalization of TNFα/TNFR1 and TNFR2 differs in cats at estrus or diestrus, receiving medroxyprogesterone acetate and suffering from pyometra, and (iii) to determine if TNFα-challenged prostaglandin secretion is stopped by prostaglandin synthases inhibitors. A total of 37 domestic adult cats in estrus or diestrus, receiving octane medroxyprogesterone or having clinical symptoms of pyometra, were enrolled in this study. The results obtained showed a distinct increase in LPS-challenged TNFα secretion in endometrial epithelial, but not stromal cells. TNFα augmented PG secretion was blocked by phospholipase A2 (PLA2) and cyclooxygeanase-2 (COX-2), but not by mitogen-activated protein kinase (MAPK) inhibitor. TNFα/TNFR1 and 2 protein expressions were limited mostly to the surface and glandular epithelium. TNFα/TNFRs protein was upregulated in the inflammatory uterus and hence may be involved in development of pathologic changes in the endometrial glands in cats receiving exogenous P4 as a hormonal contraceptive

Placental Origin of Prostaglandin F2α in the Domestic Cat

In the present study, the question was addressed whether the feline placenta can synthesize prostaglandin F2α (PGF2α). The PGFS protein was elevated, particularly at 2.5–3 weeks of pregnancy compared to 7-8 (P<0.05) and 8.5–9 weeks (P<0.001). Transcripts for PGFS were significantly upregulated at 2.5–3 weeks of pregnancy and then gradually declined towards the end of gestation (P<0.001). Transcripts for PTGS2 were only upregulated in placentas from queens close to term (P<0.001) compared with earlier phases. Staining of PTGS2 showed distinct positive signals in placentas obtained during the last week before labor, particularly in the strongly invading trophoblast surrounding blood vessels, and also in decidual cells. Shortly after implantation, signals for PGFS were localized in the trophoblast cells. Near term, PGFS staining was seen mainly in decidual cells. Both placental PGF2α and plasma PGFM were elevated towards the end of pregnancy (P<0.001) compared with earlier weeks of pregnancy. The content of PGF2α in extracted placenta mirrored the PGFM level in plasma of pregnant females. During late gestation there is a significant increase in PGFM levels in maternal blood and of PGF2α levels in placental tissue concomitant with an upregulation of placental PTGS2

Theoretical comparison of works by A. Honneth and A. Etzioni with a focus on the analysis of the concept of achievement

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