Reversible effects on female rat fertility with abrocitinib, a Janus kinase 1 inhibitor

BACKGROUND

Abrocitinib is a Janus kinase (JAK) 1 selective inhibitor approved for the treatment of atopic dermatitis. Female reproductive tissues were unaffected in general toxicity studies, but an initial female rat fertility study resulted in adverse effects at all doses evaluated. A second rat fertility study was conducted to evaluate lower doses and potential for recovery.

METHODS

This second study had 4 groups of 20 females each administered abrocitinib (0, 3, 10, or 70 mg/kg/day) 2 weeks prior to cohabitation through gestation day (GD) 7. In addition, 2 groups of 20 rats (0 or 70 mg/kg/day) were dosed for 3 weeks followed by a 4-week recovery period before mating. All mated females were evaluated on GD 14.

RESULTS

No effects were observed at ≤10 mg/kg/day. At 70 mg/kg/day (29x human exposure), decreased pregnancy rate, implantation sites, and viable embryos were observed. All these effects reversed 4 weeks after the last dose.

CONCLUSIONS

Based on these data and literature on the potential role of JAK signaling in implantation, we hypothesize that these effects may be related to JAK1 inhibition and, generally, that peri-implantation effects such as these, in the absence of cycling or microscopic changes in nonpregnant female reproductive tissues, are anticipated to be reversible.

Sequential activation of uterine epithelial IGF1R by stromal IGF1 and embryonic IGF2 directs normal uterine preparation for embryo implantation

Embryo implantation in both humans and rodents is initiated by the attachment of a blastocyst to the uterine epithelium. For blastocyst attachment, the uterine epithelium needs to transform at both the structural and molecular levels first, and then initiate the interaction with trophectoderm. Any perturbation during this process will result in implantation failure or long-term adverse pregnancy outcomes. Endocrine steroid hormones, which function through nuclear receptors, combine with the local molecules produced by the uteri or embryo to facilitate implantation. The insulin-like growth factor (IGF) signaling has been reported to play a vital role during pregnancy. However, its physiological function during implantation remains elusive. This study revealed that mice with conditional deletion of Igf1r gene in uteri suffered from subfertility, mainly due to the disturbed uterine receptivity and abnormal embryo implantation. Mechanistically, we uncovered that in response to the nidatory estrogen on D4 of pregnancy, the epithelial IGF1R, stimulated by the stromal cell-produced IGF1, facilitated epithelial STAT3 activation to modulate the epithelial depolarity. Furthermore, embryonic derived IGF2 could activate both the epithelial ERK1/2 and STAT3 signaling through IGF1R, which was critical for the transcription of Cox2 and normal attachment reaction. In brief, our data revealed that epithelial IGF1R was sequentially activated by the uterine stromal IGF1 and embryonic IGF2 to guarantee normal epithelium differentiation during the implantation process.

Contraceptive and molecular function of a novel recombinant vaccine based human leukemia inhibitory factor on Balb/c mice: An experimental in vivo study

The functional competence of leukemia inhibitory factor (LIF), as immunocontraceptive vaccine in mice, was investigated. Balb/c mice were divided into two groups of vaccinated and controls. The recombinant human LIF (rhLIF) protein and phosphate buffer saline was emulsified with Freund's adjuvant and injected into vaccinated and control groups, respectively. Theinhibition of implantation was evaluated in mice uterine. The concentration of secreted interferon-γ (IFN-γ) and interleukin (IL)-4 were measured in cultured splenocyte of mice stimulated by rhLIF. The expressions of immune responsive gene 1 (IRG-1), cochlin (COCH), amphiregulin(Ar), and heparin-binding EGF-like growth factor (HB-EGF) genes were determined. Mice were assessed for inhibition of fertility after delivery, reversibility of immune response against rhLIF, and survival rate. Active immunization of mice with rhLIF resulted in reduction of the implantation and fertility rate up to 80.49% and 75%, respectively. All mice produced a high titer of anti-rhLIF antibodies in serums and vaginal fluids washes after 16 weeks; however, these antibodies were cleared from vaginal fluid washes after six months. A significant down-regulation in mRNA levels of IRG-1, Ar and HB-EGF was observed in vaccinated group compared to controls; however, no significant change in the expression profile of cochlin gene was detected. The results showed that rhLIF prevented pregnancy in a high percentage of female mice. Although the immunization of female Balb/c mice with rhLIF inhibited fertility and expression of genes associated with this molecule, further studies are needed to support this protein as a suitable candidate for contraceptive vaccine in mammals.

Oncostatin M expression in the mouse uterus during early pregnancy promotes embryo implantation and decidualization

Oncostatin M (OSM) is a member of the interleukin-6 (IL-6) family, which functions in embryo implantation and decidualization. The expression, function and regulation of Osm in mouse uteri during early pregnancy remain unknown. We show that Osm is mainly expressed in the uterine epithelium from days 1 to 4 of pregnancy and in decidual cells on day 5 of pregnancy. Osm promotes the attachment of Osm-soaked blue beads, which mimic blastocysts, to a pseudopregnant mouse uterus. Prostaglandin E2 (PGE₂ )-induced Osm in mouse uterine epithelial cells upregulates the levels of Il-33 expression and phosphorylates Stat3. In vitro decidualization is significantly promoted by Osm. Our results indicate that PGE₂ -induced Osm may mediate embryo implantation through Il-33 and participate in decidualization via the Stat3-Egr1 pathway.

Leukemia inhibitory factor modulates the peripheral immune response in a rat model of emergent large vessel occlusion

BACKGROUND

The migration of peripheral immune cells and splenocytes to the ischemic brain is one of the major causes of delayed neuroinflammation after permanent large vessel stroke. Other groups have demonstrated that leukemia inhibitory factor (LIF), a cytokine that promotes neural cell survival through upregulation of antioxidant enzymes, promotes an anti-inflammatory phenotype in several types of immune cells. The goal of this study was to determine whether LIF treatment modulates the peripheral immune response after stroke.

METHODS

Young male (3 month) Sprague-Dawley rats underwent sham surgery or permanent middle cerebral artery occlusion (MCAO). Animals were administered LIF (125 μg/kg) or PBS at 6, 24, and 48 h prior to euthanization at 72 h. Bone marrow-derived macrophages were treated with LIF (20 ng/ml) or PBS after stimulation with interferon gamma + LPS. Western blot was used to measure protein levels of CD11b, IL-12, interferon inducible protein-10, CD3, and the LIF receptor in spleen and brain tissue. ELISA was used to measure IL-10, IL-12, and interferon gamma. Isolectin was used to label activated immune cells in brain tissue sections. Statistical analysis was performed using one-way ANOVA and Student's t test. A Kruskal-Wallis test followed by Bonferroni-corrected Mann-Whitney tests was performed if data did not pass the D'Agostino-Pearson normality test.

RESULTS

LIF-treated rats showed significantly lower levels of the LIF receptor and interferon gamma in the spleen and CD11b levels in the brain compared to their PBS-treated counterparts. Fluorescence from isolectin-binding immune cells was more prominent in the ipsilateral cortex and striatum after PBS treatment compared to LIF treatment. MCAO + LIF significantly decreased splenic levels of CD11b and CD3 compared to sham surgery. MCAO + PBS treatment significantly elevated splenic levels of interferon inducible protein-10 at 72 h after MCAO, while LIF treatment after MCAO returned interferon inducible protein 10 to sham levels. LIF administration with interferon gamma + LPS significantly reduced the IL-12/IL-10 production ratio compared to macrophages treated with interferon gamma + LPS alone.

CONCLUSIONS

These data demonstrate that LIF promotes anti-inflammatory signaling through alterations of the IL-12/interferon gamma/interferon inducible protein 10 pathway.

Tissue-Specific Ablation of the LIF Receptor in the Murine Uterine Epithelium Results in Implantation Failure

The cytokine leukemia inhibitory factor (LIF) is essential for rendering the uterus receptive for blastocyst implantation. In mice, LIF receptor expression (LIFR) is largely restricted to the uterine luminal epithelium (LE). LIF, secreted from the endometrial glands (GEs), binds to the LIFR, activating the Janus kinase-signal transducer and activation of transcription (STAT) 3 (Jak-Stat3) signaling pathway in the LE. JAK-STAT activation converts the LE to a receptive state so that juxtaposed blastocysts begin to implant. To specifically delete the LIFR in the LE, we derived a line of mice in which Cre recombinase was inserted into the endogenous lactoferrin gene (Ltf-Cre). Lactoferrin expression in the LE is induced by E2, and we demonstrate that Cre recombinase activity is restricted to the LE and GE. To determine the requirement of the LIFR in implantation, we derived an additional mouse line carrying a conditional (floxed) Lifrflx/flx gene. Crossing Ltf-Cre mice with Lifrflx/flx mice generated Lifrflx/Δ:LtfCre/+ females that were overtly normal but infertile. Many of these females, despite repeated matings, did not become pregnant. Unimplanted blastocysts were recovered from the Lifrflx/Δ:LtfCre/+ uteri and, when transferred to wild-type recipients, implanted normally, indicating that uterine receptivity rather than the embryo's competency is compromised. The loss of Lifr results in both the failure for STAT3 to translocate to the LE nuclei and a reduction in the expression of the LIF regulated gene Msx1 that regulates uterine receptivity. These results reveal that uterine expression of the LIFR is essential for embryo implantation and further define the components of the LIF signaling pathway necessary for effective implantation.

The Multifaceted Actions of Leukaemia Inhibitory Factor in Mediating Uterine Receptivity and Embryo Implantation

Embryo implantation is mediated by the combined actions of the ovarian hormones E2 and P4 on the uterus. In addition, the pro-inflammatory cytokine, leukaemia inhibitory factor (LIF), plays a pivotal role in regulating uterine receptivity. LIF is expressed in the endometrial glands and has a robust action on the uterine luminal epithelium (LE). In mice, LIF is induced by nidatory E2 and functions to convert the LE from a non-receptive to an embryo-responsive state. LIF mediates its actions by activating the JAK-STAT pathway specifically in the LE. Activation of JAK-STAT pathway results in the induction of many additional pathways, including some 40 +  transcription factors, many of which initiate a cascade of changes affecting epithelial polarity, epithelial-mesenchymal interactions, angiogenesis, stromal cell decidualization, and inhibiting cell proliferation. This review discusses the role of LIF and the recent analysis of its action on the uterine LE in regulating endometrial receptivity and implantation.

Leukemia inhibitory factor: roles in embryo implantation and in nonhormonal contraception

Leukaemia inhibitory factor (LIF) plays an indispensible role in embryo implantation. Aberrant LIF production is linked to implantation failure. LIF regulates multiple processes prior to and during implantation such as uterine transformation into a receptive state, decidualization, blastocyst growth and development, embryo-endometrial interaction, trophoblast invasion, and immune modulation. Due to its critical role, LIF has been a target for a nonhormonal contraception. In this review, we summarize up-to-date information on the role of LIF in implantation and its role in contraception.

The LIF-mediated molecular signature regulating murine embryo implantation

The establishment of a receptive uterus is the prime requirement for embryo implantation. In mice, the E2-induced cytokine leukemia inhibitory factor (LIF) is essential in switching the uterine luminal epithelium (LE) from a nonreceptive to a receptive state. Here we define the LIF-mediated switch using array analysis and informatics to identify LIF-induced changes in gene expression and annotated signaling pathways specific to the LE. We compare gene expression profiles at 0, 1, 3, and 6 h, following LIF treatment. During the first hour, the JAK-STAT signaling pathway is activated and the expression of 54 genes declines, primarily affecting LE cytoskeletal and chromatin organization as well as a transient reduction in the progesterone, TGFbetaR1, and ACVR1 receptors. Simultaneously 256 genes increase expression, of which 42 are transcription factors, including Sox, Kfl, Hes, Hey, and Hox families. Within 3 h, the expression of 3987 genes belonging to more than 25 biological process pathways was altered. We confirmed the mRNA and protein distribution of key genes from 10 pathways, including the Igf-1, Vegf, Toll-like receptors, actin cytoskeleton, ephrin, integrins, TGFbeta, Wnt, and Notch pathways. These data identify novel LIF-activated pathways in the LE and define the molecular basis between the refractory and receptive uterine phases. More broadly, these findings highlight the staggering capacity of a single cytokine to induce a dynamic and complex network of changes in a simple epithelium essential to mammalian reproduction and provide a basis for identifying new routes to regulating female reproduction.

Physiological and molecular determinants of embryo implantation

Embryo implantation involves the intimate interaction between an implantation-competent blastocyst and a receptive uterus, which occurs in a limited time period known as the window of implantation. Emerging evidence shows that defects originating during embryo implantation induce ripple effects with adverse consequences on later gestation events, highlighting the significance of this event for pregnancy success. Although a multitude of cellular events and molecular pathways involved in embryo-uterine crosstalk during implantation have been identified through gene expression studies and genetically engineered mouse models, a comprehensive understanding of the nature of embryo implantation is still missing. This review focuses on recent progress with particular attention to physiological and molecular determinants of blastocyst activation, uterine receptivity, blastocyst attachment and uterine decidualization. A better understanding of underlying mechanisms governing embryo implantation should generate new strategies to rectify implantation failure and improve pregnancy rates in women.

The LIF receptor antagonist PEGLA is effectively delivered to the uterine endometrium and blocks LIF activity in cynomolgus monkeys

BACKGROUND

Leukemia inhibitory factor (LIF) is a cytokine with an essential role in the preparation of the endometrium for implantation. Previous studies demonstrated that PEGLA, a LIF receptor antagonist (LA) conjugated with polyethylene glycol (PEG), effectively prevents implantation in mice, identifying PEGLA as a potential contraceptive for women.

STUDY DESIGN

Adult female cynomolgus macaques were used to determine the optimal route of administration to deliver PEGLA to the uterine endometrium. Endometrial explants were used to examine the ability of PEGLA to block LIF action at endometrial cells.

RESULTS

Both intramuscular and subcutaneous PEGLA administration resulted in peak serum PEGLA 24 h after administration; serum PEGLA was detectable throughout the 144-h sampling period. In contrast, serum PEGLA was near or below the limit of detection after vaginal administration. After intramuscular administration, PEGLA was localized to both luminal and glandular epithelial cells of the uterine endometrium, and PEGLA was measurable in endometrial lysates. PEGLA administration reduced endometrial signal transducer and activator of transcription protein 3 (STAT3) phosphorylation in vivo and in vitro. PEGLA also blocked LIF's ability to elevate expression of cochlin, insulin-like growth factor-binding protein 3, vascular endothelial growth factor A, and cyclooxygenase-2 (also known as PTGS2) in endometrial explants in vitro.

CONCLUSIONS

PEGLA was delivered to the non-human primate uterine endometrium with systemic administration, and PEGLA blocked LIF actions associated with implantation. Blocking LIF receptor activity with the antagonist PEGLA may prevent pregnancy in women and provide a novel alternative to currently-available hormonal and barrier contraceptives.

Alpha-secretase inhibition reduces human glioblastoma stem cell growth in vitro and in vivo by inhibiting Notch

The Notch pathway is dysregulated and a potential target in glioblastoma multiforme (GBM). Currently available Notch inhibitors block γ-secretase, which is necessary for Notch processing. However, Notch is first cleaved by α-secretase outside the plasma membrane, via a disintegrin and metalloproteinase-10 and -17. In this work, we used a potent α-secretase inhibitor (ASI) to test inhibition of glioblastoma growth and inhibition of Notch and of both novel and known Notch targets. Featured in this study are luciferase reporter assays and immunoblot, microarray analysis, chromatin immunoprecipitation (ChIP), quantitative real-time PCR, cell number assay, bromodeoxyuridine incorporation, plasmid rescue, orthotopic xenograft model, and local delivery of treatment with convection-enhanced delivery using nanoparticles, as well as survival, MRI, and ex vivo luciferase assay. A CBF1-luciferase reporter assay as well as an immunoblot of endogenous Notch revealed Notch inhibition by the ASI. Microarray analysis, quantitative real-time PCR, and ChIP of ASI and γ-secretase inhibitor (GSI) treatment of GBM cells identified known Notch pathway targets, as well as novel Notch targets, including YKL-40 and leukemia inhibitory factor. Finally, we found that local nanoparticle delivery of ASIs but not GSIs increased survival time significantly in a GBM stem cell xenograft treatment model, and ASI treatment resulted in decreased tumor size and Notch activity. This work indicates α-secretase as an alternative to γ-secretase for inhibition of Notch in GBM and possibly other cancers as well, and it identifies novel Notch targets with biologic relevance and potential as biomarkers.

Leukemia inhibitory factor enhances endometrial stromal cell decidualization in humans and mice

Adequate differentiation or decidualization of endometrial stromal cells (ESC) is critical for successful pregnancy in humans and rodents. Here, we investigated the role of leukemia inhibitory factor (LIF) in human and murine decidualization. Ex vivo human (H) ESC decidualization was induced by estrogen (E, 10(-8) M) plus medroxyprogesterone acetate (MPA, 10(-7) M). Exogenous LIF (≥50 ng/ml) induced STAT3 phosphorylation in non-decidualized and decidualized HESC and enhanced E+MPA-induced decidualization (measured by PRL secretion, P<0.05). LIF mRNA in HESC was down-regulated by decidualization treatment (E+MPA) whereas LIF receptor (R) mRNA was up-regulated, suggesting that the decidualization stimulus 'primed' HESC for LIF action, but that factors not present in our in vitro model were required to induce LIF expression. Ex vivo first trimester decidual biopsies secreted >100 pg/mg G-CSF, IL6, IL8, and MCP1. Decidualized HESC secreted IL6, IL8, IL15 and MCP1. LIF (50 ng/ml) up-regulated IL6 and IL15 (P<0.05) secretion in decidualized HESC compared to 0.5 ng/ml LIF. In murine endometrium, LIF and LIFR immunolocalized to decidualized stromal cells on day 5 of gestation (day 0 = day of plug detection). Western blotting confirmed that LIF and the LIFR were up-regulated in intra-implantation sites compared to inter-implantation sites on Day 5 of gestation. To determine the role of LIF during in vivo murine decidualization, intra-peritoneal injections of a long-acting LIF antagonist (PEGLA; 900 or 1200 µg) were given just post-attachment, during the initiation of decidualization on day 4. PEGLA treatment reduced implantation site decidual area (P<0.05) and desmin staining immuno-intensity (P<0.05) compared to control on day 6 of gestation. This study demonstrated that LIF was an important regulator of decidualization in humans and mice and data provides insight into the processes underlying decidualization, which are important for understanding implantation and placentation.

Embryo implantation is blocked by intraperitoneal injection with anti-LIF antibody in mice

Leukemia inhibitory factor (LIF) is essential for embryo implantation in mice and plays an important role in other mammals including humans. Intraperitoneal (i.p.) injections with anti-LIF antibody (7.5 µg/g body weight, 3 times) between D3 (D1 = day of vaginal plug detection) and D4 effectively blocked embryo implantation; complete inhibition was achieved in C57BL/6J mice, and implantation was dramatically reduced in ICR mice (reduced to 27%). Normal rabbit IgG used as the control did not disturb embryo implantation. Anti-LIF antibody was localized not only in the stroma, but also in the luminal epithelium and the glandular lumen after i.p. injections. Growth-arrested blastocysts were recovered from the uterus without any implantation sites in both strains. Blastocysts made contact with the LE on the antimesometrial side; however, uterine stromal cells did not undergo secondary decidual reaction, and the uterine lumen was open, even at D7. Several regions of decidualization in ICR mice treated with anti-LIF antibody were smaller than those of the control, and development of blastocysts was delayed. The expression of LIF-regulated genes, such as immune-responsive gene-1 and insulin-like growth factor binding protein-3, was significantly decreased in C57BL/6J mice treated with anti-LIF antibody compared with the control, but not in ICR mice. The present study demonstrated that simple ip injections of an antibody are sufficient to block one of the important factors involved in embryo implantation in mice, and this method should also be easily applicable to the investigation of other factors involved in implantation.

Contraceptive vaccines targeting factors involved in establishment of pregnancy

Current methods of contraception lack specificity and are accompanied with serious side effects. A more specific method of contraception is needed. Contraceptive vaccines can provide most, if not all, the desired characteristics of an ideal contraceptive. This article reviews several factors involved in the establishment of pregnancy, focusing on those that are essential for successful implantation. Factors that are both essential and pregnancy-specific can provide potential targets for contraception. Using database search, 76 factors (cytokines/chemokines/growth factors/others) were identified that are involved in various steps of the establishment of pregnancy. Among these factors, three, namely chorionic gonadotropin (CG), leukemia inhibitory factor (LIF), and pre-implantation factor (PIF), are found to be unique and exciting molecules. Human CG is a well-known pregnancy-specific protein that has undergone phase I and phase II clinical trials, in women, as a contraceptive vaccine with encouraging results. LIF and PIF are pregnancy-specific and essential for successful implantation. These molecules are intriguing and may provide viable targets for immunocontraception. A multiepitope vaccine combining factors/antigens involved in various steps of the fertilization cascade and pregnancy establishment may provide a highly immunogenic and efficacious modality for contraception in humans.

Interpreting the stress response of early mammalian embryos and their stem cells

This review analyzes and interprets the normal, pathogenic, and pathophysiological roles of stress and stress enzymes in mammalian development. Emerging data suggest that stem cells from early embryos are induced by stress to perform stress-enzyme-mediated responses that use the strategies of compensatory, prioritized, and reversible differentiation. These strategies have been optimized during evolution and in turn have aspects of energy conservation during stress that optimize and maximize the efficacy of the stress response. It is likely that different types of stem cells have varying degrees of flexibility in mediating compensatory and prioritized differentiation. The significance of this analysis and interpretation is that it will serve as a foundation for yielding tools for diagnosing, understanding normal and pathophysiological mechanisms, and providing methods for managing stress enzymes to improve short- and long-term reproductive outcomes.