Two-Month Voluntary Ethanol Consumption Promotes Mild Neuroinflammation in the Cerebellum but Not in the Prefrontal Cortex, Hippocampus, or Striatum of Mice

Chronic ethanol exposure often triggers neuroinflammation in the brain's reward system, potentially promoting the drive for ethanol consumption. A main marker of neuroinflammation is the microglia-derived monocyte chemoattractant protein 1 (MCP1) in animal models of alcohol use disorder in which ethanol is forcefully given. However, there are conflicting findings on whether MCP1 is elevated when ethanol is taken voluntarily, which challenges its key role in promoting motivation for ethanol consumption. Here, we studied MCP1 mRNA levels in areas implicated in consumption motivation-specifically, the prefrontal cortex, hippocampus, and striatum-as well as in the cerebellum, a brain area highly sensitive to ethanol, of C57BL/6 mice subjected to intermittent and voluntary ethanol consumption for two months. We found a significant increase in MCP1 mRNA levels in the cerebellum of mice that consumed ethanol compared to controls, whereas no significant changes were observed in the prefrontal cortex, hippocampus, or striatum or in microglia isolated from the hippocampus and striatum. To further characterize cerebellar neuroinflammation, we measured the expression changes in other proinflammatory markers and chemokines, revealing a significant increase in the proinflammatory microRNA miR-155. Notably, other classical proinflammatory markers, such as TNFα, IL6, and IL-1β, remained unaltered, suggesting mild neuroinflammation. These results suggest that the onset of neuroinflammation in motivation-related areas is not required for high voluntary consumption in C57BL/6 mice. In addition, cerebellar susceptibility to neuroinflammation may be a trigger to the cerebellar degeneration that occurs after chronic ethanol consumption in humans.

New insight into the role of macrophages in ovarian function and ovarian aging

Macrophages (MΦs) are the most abundant leukocytes in mammalian ovaries that have heterogeneity and plasticity. A body of evidence has indicated that these cells are important in maintaining ovarian homeostasis and they play critical roles in ovarian physiological events, such as folliculogenesis, ovulation, corpus luteum formation and regression. As females age, ovarian tissue microenvironment is typified by chronic inflammation with exacerbated ovarian fibrosis. In response to specific danger signals within aged ovaries, macrophages polarize into different M1 or M2 phenotypes, and specialize in unique functions to participate in the ovarian aging process. In this review, we will focus on the physiologic roles of MΦs in normal ovarian functions. Furthermore, we will discuss the roles of MΦs in the process of ovarian senescence, as well as the novel techniques applied in this field.

Expression of genes regulating cell division in porcine follicular granulosa cells

BACKGROUND

Cell cycle regulation influences the proliferation of granulosa cells and affects many processes related to ovarian folliclular growth and ovulation. Abnormal regulation of the cell cycle can lead to many diseases within the ovary. The aim of this study was to describe the expression profile of genes within granulosa cells, which are related to the formation of the cytoskeleton, organization of cell organelles inside the cell, and regulation of cell division. Established in vitro primary cultures from porcine ovarian follicle granulosa cells were maintained for 48, 96, 144 h and evaluated via microarray expression analysis.

RESULTS

Analyzed genes were assigned to 12 gene ontology groups "actin cytoskeleton organization", "actin filament organization", "actin filament-based process", "cell-matrix adhesion", "cell-substrate adhesion", "chromosome segregation", "chromosome separation", "cytoskeleton organization", "DNA integrity checkpoint", "DNA replication initiation", "organelle fision", "organelle organization". Among the genes with significantly changed expression, those whose role in processes within the ovary are selected for consideration. Genes with increased expression include (ITGA11, CNN1, CCl2, TPM2, ACTN1, VCAM-1, COL3A1, GSN, FRMD6, PLK2). Genes with reduced expression inlcude (KIF14, TACC3, ESPL1, CDC45, TTK, CDC20, CDK1, FBXO5, NEK2-NIMA, CCNE2). For the results obtained by microarray expressions, quantitative validation by RT-qPCR was performed.

CONCLUSIONS

The results indicated expression profile of genes, which can be considered as new molecular markers of cellular processes involved in signaling, cell structure organization. The expression profile of selected genes brings new insight into regulation of physiological processes in porcine follicular granulosa cells during primary in vitro culture.

Macrophages: an indispensable piece of ovarian health

Macrophages are the most abundant immune cells in the ovary. In addition to their roles in the innate immune system, these heterogeneous tissue-resident cells are responsive to tissue-derived signals, adapt to their local tissue environment, and specialize in unique functions to maintain tissue homeostasis. Research in the past decades has established a strong link between macrophages and various aspects of ovarian physiology, indicating a pivotal role of macrophages in ovarian health. However, unlike other intensively studied organs, the knowledge of ovarian macrophages dates back to the time when the heterogeneity of ontogeny, phenotype, and function of macrophages was not fully understood. In this review, we discuss the evolving understanding of the biology of ovarian tissue-resident macrophages, highlight their regulatory roles in normal ovarian functions, review the association between certain ovarian pathologies and disturbed macrophage homeostasis, and finally, discuss the technologies that are essential for addressing key questions in the field.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

Progesterone inhibits cytokine/TNF-α production by porcine CL macrophages via the genomic progesterone receptor

In pigs, luteolytic sensitivity to PGF-2α (=LS) is delayed until d 13 of the estrous cycle. While the control of LS is unknown, it is temporally associated with macrophage (MAC; which secretes tumor necrosis factor [TNF]-α) infiltration into the corpora lutea (CL), and previous studies have shown that TNF-α induces LS in porcine luteal cells (LCs) in culture. This study was designed to explore the control of LS by CL macrophage (CL MAC)/TNF-α by progesterone (P4), and to examine the hypothesis that P4 acting via the genomic P4 receptor (PGR) inhibits CL MAC TNF-α and thus plays a key role in regulating LS during the pig estrous cycle. In experiment 1, the effects of LCs on CL MAC cytokine/TNF-α mRNA expression in co-culture were examined (MID cycle; ~d 7-12; no LS); results showed that LC was inhibitory to cytokine/TNF-α. In experiment 2, the effects of P4 or R5020 (PGR-agonist) on CL MAC cytokine/TNF-α mRNA expression were examined (MID cycle; ~d 7-12; no LS); results showed that both P4 and R5020 dose-dependently inhibited TNF-α. In experiment 3, CL MACs were isolated from CL at MID (~d 7-12; no LS) and LATE (~d 13-18; + LS) cycle, and TNF-α/PGR mRNA measured. Results indicated that while TNF-α mRNA was 4.2-fold greater in CL MACs from LATE vs MID cycle, PGR mRNA was 4.5-fold greater in CL MACs from MID vs LATE cycle. These data support our hypothesis and suggest that progesterone, acting via PGR, plays a critical physiological role in the control of TNF-α production by CL MACs and LS during the pig estrous cycle.

Luteal Lipids Regulate Progesterone Production and May Modulate Immune Cell Function During the Estrous Cycle and Pregnancy

Although the corpus luteum (CL) contains high concentrations of lipid in the form of steroid hormone precursors and prostaglandins, little is known about the abundance or function of other luteal lipid mediators. To address this, 79 lipid mediators were measured in bovine CL, using ultra performance liquid chromatography-tandem mass spectrometry. CL from estrous cycle days 4, 11, and 18 were compared and, separately, CL from days 18 of the estrous cycle and pregnancy were compared. Twenty-three lipids increased as the estrous cycle progressed (P < 0.05), with nine increasing between days 4 and 11 and fourteen increasing between days 4 and 18. Overall, this indicated a general upregulation of lipid mediator synthesis as the estrous cycle progressed, including increases in oxylipins and endocannabinoids. Only 15-KETE was less abundant in the CL of early pregnancy (P < 0.05), with a tendency (P < 0.10) for four others to be less abundant. Notably, 15-KETE also increased between estrous cycle days 4 and 18. Ingenuity Pathway Analysis (IPA, Qiagen) indicated that functions associated with differentially abundant lipids during the estrous cycle included leukocyte activation, cell migration, and cell proliferation. To investigate changes in CL during maternal recognition of pregnancy, this lipid dataset was integrated with a published dataset from mRNA profiling during maternal recognition of pregnancy. This analysis indicated that lipids and mRNA that changed during maternal recognition of pregnancy may regulate some of the same functions, including immune cell chemotaxis and cell-cell communication. To assess effects of these lipid mediators, luteal cells were cultured with 5-KETE or 15-KETE. One ng/mL 5-KETE reduced luteal progesterone on day 1 of culture, only in the absence of luteinizing hormone (LH), while 1 ng/mL 15-KETE induced progesterone only in the presence of LH (10 ng/mL). On day 7 of culture, 0.1 ng/mL 15-KETE reduced prostaglandin (PG)F2A-induced inhibition of LH-stimulated progesterone production, while 1 ng/mL 15-KETE did not have this effect. Overall, these data suggest a role for lipid mediators during luteal development and early pregnancy, as regulators of steroidogenesis, immune cell activation and function, intracellular signaling, and cell survival and death.

Ovulation: Parallels With Inflammatory Processes

The midcycle surge of LH sets in motion interconnected networks of signaling cascades to bring about rupture of the follicle and release of the oocyte during ovulation. Many mediators of these LH-induced signaling cascades are associated with inflammation, leading to the postulate that ovulation is similar to an inflammatory response. First responders to the LH surge are granulosa and theca cells, which produce steroids, prostaglandins, chemokines, and cytokines, which are also mediators of inflammatory processes. These mediators, in turn, activate both nonimmune ovarian cells as well as resident immune cells within the ovary; additional immune cells are also attracted to the ovary. Collectively, these cells regulate proteolytic pathways to reorganize the follicular stroma, disrupt the granulosa cell basal lamina, and facilitate invasion of vascular endothelial cells. LH-induced mediators initiate cumulus expansion and cumulus oocyte complex detachment, whereas the follicular apex undergoes extensive extracellular matrix remodeling and a loss of the surface epithelium. The remainder of the follicle undergoes rapid angiogenesis and functional differentiation of granulosa and theca cells. Ultimately, these functional and structural changes culminate in follicular rupture and oocyte release. Throughout the ovulatory process, the importance of inflammatory responses is highlighted by the commonalities and similarities between many of these events associated with ovulation and inflammation. However, ovulation includes processes that are distinct from inflammation, such as regulation of steroid action, oocyte maturation, and the eventual release of the oocyte. This review focuses on the commonalities between inflammatory responses and the process of ovulation.

Genomic profiling of bovine corpus luteum maturation

To unveil novel global changes associated with corpus luteum (CL) maturation, we analyzed transcriptome data for the bovine CL on days 4 and 11, representing the developing vs. mature gland. Our analyses revealed 681 differentially expressed genes (363 and 318 on day 4 and 11, respectively), with ≥2 fold change and FDR of <5%. Different gene ontology (GO) categories were represented prominently in transcriptome data at these stages (e.g. days 4: cell cycle, chromosome, DNA metabolic process and replication and on day 11: immune response; lipid metabolic process and complement activation). Based on bioinformatic analyses, select genes expression in day 4 and 11 CL was validated with quantitative real-time PCR. Cell specific expression was also determined in enriched luteal endothelial and steroidogenic cells. Genes related to the angiogenic process such as NOS3, which maintains dilated vessels and MMP9, matrix degrading enzyme, were higher on day 4. Importantly, our data suggests day 11 CL acquire mechanisms to prevent blood vessel sprouting and promote their maturation by expressing NOTCH4 and JAG1, greatly enriched in luteal endothelial cells. Another endothelial specific gene, CD300LG, was identified here in the CL for the first time. CD300LG is an adhesion molecule enabling lymphocyte migration, its higher levels at mid cycle are expected to support the transmigration of immune cells into the CL at this stage. Together with steroidogenic genes, most of the genes regulating de-novo cholesterol biosynthetic pathway (e.g HMGCS, HMGCR) and cholesterol uptake from plasma (LDLR, APOD and APOE) were upregulated in the mature CL. These findings provide new insight of the processes involved in CL maturation including blood vessel growth and stabilization, leucocyte transmigration as well as progesterone synthesis as the CL matures.

Parity-Dependent Hemosiderin and Lipofuscin Accumulation in the Reproductively Aged Mouse Ovary

The progressive decline of the ovarian follicle pool leads to reproductive ageing. The latter is accompanied by age-related disorders, including various types of cancer. In fact, the highest rates of ovarian cancer (OC) occur at postmenopause while OC risk is significantly modulated by parity records during previous fertile life. We approached the age-parity relationship in the C57BL/6 mouse model and herein describe the presence of nonheme iron (hemosiderin) and deposits of the "age pigment" lipofuscin in reproductively aged mouse ovaries by applying conventional histochemical methods and autofluorescence. In addition, the 8-OHdG adduct was evaluated in ovarian genomic DNA. Both hemosiderin and lipofuscin were significantly higher in virgin compared to multiparous ovaries. The same pattern was observed for 8-OHdG. We conclude that nulliparity induces a long-term accumulation of iron and lipofuscin with concomitant oxidative damage to DNA in the mouse ovary. Since lipofuscin is a widely accepted senescence marker and given the recently postulated role of lipofuscin-associated iron as a source of reactive oxygen species (ROS) in senescent cells, these findings suggest a possible pathogenic mechanism by which nulliparity contributes to an increased OC risk in the postmenopausal ovary.

Loss of luteotropic prostaglandin E plays an important role in the regulation of luteolysis in women

STUDY QUESTION

Do intraluteal prostaglandins (PG) contribute to luteal regulation in women?

SUMMARY ANSWER

Prostaglandin E (PGE), which is produced in human granulosa-lutein cells stimulated with luteotropic hCG, exerts similar luteotropic effects to hCG, and the expression of PG synthetic and metabolic enzymes in the human CL is driven toward less PGE but more prostaglandin F (PGF) during luteolysis.

WHAT IS KNOWN ALREADY

Uterine PGF is a major luteolysin in many non-primate species but not in women. Increases in the PGF synthase, aldo-ketoreductase family one member C3 (AKR1C3), have been observed in the CL of marmoset monkeys during luteolysis. PGE prevents spontaneous or induced luteolysis in domestic animals.

STUDY DESIGN, SIZE, DURATION

Human CL tissues staged as the early-luteal (n = 6), mid-luteal (n = 6), late-luteal (n = 5) and menstrual (n = 3) phases were obtained at the time of hysterectomy for benign gynecological conditions. Luteinized granulosa cells (LGCs) were purified from follicular fluids obtained from patients undergoing assisted conception.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Upon collection, one half of the CL was snap-frozen and the other was fixed with formalin and processed for immunohistochemical analysis of a PGE synthase (PTGES). Quantitative RT-PCR was employed to examine changes in the mRNA abundance of PG synthetic and metabolic enzymes, steroidogenic enzymes, and luteolytic molecules in the staged human CL and in human LGCs in vitro treated with hCG, PGE and PGF. A PGE withdrawal experiment was also conducted in order to reveal the effects of the loss of PGE in LGCs. Progesterone concentrations in the culture medium were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

The key enzyme for PGE synthesis, PTGES mRNA was abundant in the functional CL during the mid-luteal phase (P < 0.01), while mRNA abundance for genes involved in PGF synthesis (AKR1B1 and AKR1C1-3) increased in the CL during the late-luteal phase and menstruation (P < 0.05-0.001). PTGES mRNA expression positively correlated with that of 3β-hydroxysteroid dehydrogenase (HSD3B1; r = 0.7836, P < 0.001), while AKR1C3 expression inversely correlated with that of HSD3B1 (r = -0.7514, P = 0.0012) and PTGES (r = -0.6923, P = 0.0042). PGE exerted similar effects to hCG-promoting genes, such as steroidogenic acute regulatory protein (STAR) and HSD3B1, to produce progesterone and luteotropic PGE, suppress PGF synthetic enzymes and down-regulate luteolytic molecules such as βA- and βB-inhibin subunits (INHBA and INHBB) and bone morphogenetic proteins (BMP2, BMP4 and BMP6). PGE withdrawal resulted in reductions in the enzymes that produce progesterone (STAR; P < 0.001) and PGE (PTGES; P < 0.001), and the capacity to produce PGE decreased, while the capacity to produce PGF increased during the culture. The addition of PGF did not recapitulate the luteolytic effects of PGE withdrawal.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

Changes in mRNA expression of PG synthetic and metabolic enzymes may not represent actual increases in PGF during luteolysis in the CL. The effects of PGF on luteal cells currently remain unclear and the mechanisms responsible for decreases in the synthesis of PGE in vitro and at luteolysis have not been elucidated in detail.

WIDER IMPLICATIONS OF THE FINDINGS

The results obtained strongly support a luteotropic function of PGE in regulation of the human CL. They suggest that the main PG produced in human luteal tissue changes from PGE to PGF during the maturation and regression of the CL, and the loss of PGE is more important than the effects of PGF during luteolysis in women. This may be accompanied by reduced effects of LH/hCG in luteal cells, particularly decreased activation of cAMP/protein kinase A; however, the underlying mechanisms remain unknown.

STUDY FUNDING AND COMPETING INTEREST(S)

This study was supported by the Cunningham Trust to WCD, a Postdoctoral Fellowship for Research Abroad from the Japan Society for the Promotion of Science and the Suntory Foundation for Life Sciences to J.N.-K.; W.C.D. is supported by an MRC Centre Grant G1002033 and a Scottish Senior Clinical Fellowship. The authors have nothing to disclose.

Parity History Determines a Systemic Inflammatory Response to Spread of Ovarian Cancer in Naturally Aged Mice

Aging intersects with reproductive senescence in women by promoting a systemic low-grade chronic inflammation that predisposes women to several diseases including ovarian cancer (OC). OC risk at menopause is significantly modified by parity records during prior fertile life. To date, the combined effects of age and parity on the systemic inflammation markers that are particularly relevant to OC initiation and progression at menopause remain largely unknown. Herein, we profiled a panel of circulating cytokines in multiparous versus virgin C57BL/6 female mice at peri-estropausal age and investigated how cytokine levels were modulated by intraperitoneal tumor induction in a syngeneic immunocompetent OC mouse model. Serum FSH, LH and TSH levels increased with age in both groups while prolactin (PRL) was lower in multiparous respect to virgin mice, a finding previously observed in parous women. Serum CCL2, IL-10, IL-5, IL-4, TNF-α, IL1-β and IL-12p70 levels increased with age irrespective of parity status, but were specifically reduced following OC tumor induction only in multiparous mice. Animals developed hemorrhagic ascites and tumor implants in the omental fat band and other intraperitoneal organs by 12 weeks after induction, with multiparous mice showing a significantly extended survival. We conclude that previous parity history counteracts aging-associated systemic inflammation possibly by reducing the immunosuppression that typically allows tumor spread. Results suggest a partial impairment of the M2 shift in tumor-associated macrophages as well as decreased stimulation of regulatory B-cells in aged mice. This long term, tumor-concurrent effect of parity on inflammation markers at menopause would be a contributing factor leading to decreased OC risk.

Changes in immune cell distribution and their cytokine/chemokine production during regression of the rhesus macaque corpus luteum

Our previous flow cytometry results demonstrated a significant increase in neutrophils, macrophages/monocytes, and natural killer (NK) cells in dispersed rhesus monkey corpora lutea (CL) after progesterone (P4) levels had fallen below 0.3 ng/ml for ≥3 days during the natural menstrual cycle. In this study, immunohistochemistry revealed the CD11b+ cells (neutrophils, macrophages/monocytes) present in the CL after luteal P4 synthesis ceased were distributed throughout the tissue. CD16+ cells (presumptive NK cells) were observed mainly near the vasculature in functional CL, until their numbers increased and they became widely distributed in regressing CL. To determine if the immune cells that enter luteal tissue during structural regression are functionally different from those that are present during peak function, CD11b+ or CD16+ populations were enriched from mid-late stage (functional) and regressing (days 1.8 ± 0.3 postmenses) CL using antibody-conjugated magnetic microbeads. Flow cytometry analyses revealed the majority of CD11b+ cells expressed CD14, a protein mainly produced by macrophages/monocytes. The antibody-enriched and depleted fractions were cultured for 24 h, and the media then analyzed for the production of 29 cytokines/chemokines. From the mid-late CL, the CD11b+-enriched fraction produced three cytokines/chemokines, whereas CD16+-enriched cells only produced the chemokine CCL2. However, CD11b +-enriched cells isolated from regressed CL produced eight cytokines/chemokines. The CD16+-enriched cells isolated from regressing CL produced significant levels of only three cytokines. Thus, the CD11b+ cells that appear in the rhesus macaque CL after functional regression produce several cytokines/chemokines that likely play a role in orchestrating structural regression.

Hypothyroidism Reduces the Size of Ovarian Follicles and Promotes Hypertrophy of Periovarian Fat with Infiltration of Macrophages in Adult Rabbits

Ovarian failure is related to dyslipidemias and inflammation, as well as to hypertrophy and dysfunction of the visceral adipose tissue (VAT). Although hypothyroidism has been associated with obesity, dyslipidemias, and inflammation in humans and animals, its influence on the characteristics of ovarian follicles in adulthood is scarcely known. Control and hypothyroid rabbits were used to analyze the ovarian follicles, expression of aromatase in the ovary, serum concentration of lipids, leptin, and uric acid, size of adipocytes, and infiltration of macrophages in the periovarian VAT. Hypothyroidism did not affect the percentage of functional or atretic follicles. However, it reduced the size of primary, secondary, and tertiary follicles considered as large and the expression of aromatase in the ovary. This effect was associated with high serum concentrations of total cholesterol and low-density lipoprotein cholesterol (LDL-C). In addition, hypothyroidism induced hypertrophy of adipocytes and a major infiltration of CD68+ macrophages into the periovarian VAT. Our results suggest that the reduced size of ovarian follicles promoted by hypothyroidism could be associated with dyslipidemias, hypertrophy, and inflammation of the periovarian VAT. Present findings may be useful to understand the influence of hypothyroidism in the ovary function in adulthood.

Tissue- and cell-specific localization of galectins, β-galactose-binding animal lectins, and their potential functions in health and disease

Fifteen galectins, β-galactose-binding animal lectins, are known to be distributed throughout the body. We herein summarize current knowledge on the tissue- and cell-specific localization of galectins and their potential functions in health and disease. Galectin-3 is widely distributed in epithelia, including the simple columnar epithelium in the gut, stratified squamous epithelium in the gut and skin, and transitional epithelium and several regions in nephrons in the urinary tract. Galectin-2 and galectin-4/6 are gut-specific, while galectin-7 is found in the stratified squamous epithelium in the gut and skin. The reproductive tract mainly contains galectin-1 and galectin-3, and their expression markedly changes during the estrous/menstrual cycle. The galectin subtype expressed in the corpus luteum (CL) changes in association with luteal function. The CL of women and cows displays a "galectin switch" with coordinated changes in the major galectin subtype and its ligand glycoconjugate structure. Macrophages express galectin-3, which may be involved in phagocytotic activity. Lymphoid tissues contain galectin-3-positive macrophages, which are not always stained with the macrophage marker, F4/80. Subsets of neurons in the brain and dorsal root ganglion express galectin-1 and galectin-3, which may contribute to the regeneration of damaged axons, stem cell differentiation, and pain control. The subtype-specific contribution of galectins to implantation, fibrosis, and diabetes are also discussed. The function of galectins may differ depending on the tissues or cells in which they act. The ligand glycoconjugate structures mediated by glycosyltransferases including MGAT5, ST6GAL1, and C2GnT are important for revealing the functions of galectins in healthy and disease states.

Dynamics of Immune Cell Types Within the Macaque Corpus Luteum During the Menstrual Cycle: Role of Progesterone

The goal of the current study was to characterize the immune cell types within the primate corpus luteum (CL). Luteal tissue was collected from rhesus females at discrete intervals during the luteal phase of the natural menstrual cycle. Dispersed cells were incubated with fluorescently labeled antibodies specific for the immune cell surface proteins CD11b (neutrophils and monocytes/macrophages), CD14 (monocytes/macrophages), CD16 (natural killer [NK] cells), CD20 (B-lymphocytes), and CD3epsilon (T-lymphocytes) for analysis by flow cytometry. Numbers of CD11b-positive (CD11b(+)) and CD14(+) cells increased significantly 3 to 4 days after serum progesterone (P4) concentrations declined below 0.3 ng/ml. CD16(+) cells were the most abundant immune cell type in CL during the mid and mid-late luteal phases and were 3-fold increased 3 to 4 days after serum P4 decreased to baseline levels. CD3epsilon(+) cells tended to increase 3 to 4 days after P4 decline. To determine whether immune cells were upregulated by the loss of luteotropic (LH) support or through loss of LH-dependent steroid milieu, monkeys were assigned to 4 groups: control (no treatment), the GnRH antagonist Antide, Antide plus synthetic progestin (R5020), or Antide plus the estrogen receptor agonists diarylpropionitrile (DPN)/propyl-pyrazole-triol (PPT) during the mid-late luteal phase. Antide treatment increased the numbers of CD11b(+) and CD14(+) cells, whereas progestin, but not estrogen, replacement suppressed the numbers of CD11b(+), CD14(+), and CD16(+) cells. Neither Antide nor steroid replacement altered numbers of CD3epsilon(+) cells. These data suggest that increased numbers of innate immune cells in primate CL after P4 synthesis declines play a role in onset of structural regression of primate CL.