Applying Embryo-Derived Immune Tolerance to the Treatment of Immune Disorders

Pharmacological activation of insulin-degrading enzyme improves insulin secretion and glucose tolerance in diet-induced obese mice

AIM

To investigate the use of synthetic preimplantation factor (sPIF) as a potential therapeutic tool for improving glucose-stimulated insulin secretion (GSIS), glucose tolerance and insulin sensitivity in the setting of diabetes.

MATERIALS AND METHODS

We used a preclinical murine model of type 2 diabetes (T2D) induced by high-fat diet (HFD) feeding for 12 weeks. Saline or sPIF (1 mg/kg/day) was administered to mice by subcutaneously implanted osmotic mini-pumps for 25 days. Glucose tolerance, circulating insulin and C-peptide levels, and GSIS were assessed. In addition, β-cells (Min-6) were used to test the effects of sPIF on GSIS and insulin-degrading enzyme (IDE) activity in vitro. The effect of sPIF on GSIS was also tested in human islets.

RESULTS

GSIS was enhanced 2-fold by sPIF in human islets ex vivo. Furthermore, continuous administration of sPIF to HFD mice increased circulating levels of insulin and improved glucose tolerance, independently of hepatic insulin clearance. Of note, islets isolated from mice treated with sPIF exhibited restored β-cell function. Finally, genetic (shRNA-IDE) or pharmacological (6bK) inactivation of IDE in Min-6 abolished sPIF-mediated effects on GSIS, showing that both the protein and its protease activity are required for its action.

CONCLUSIONS

We conclude that sPIF is a promising secretagogue for the treatment of T2D.

Preimplantation factor modulates oligodendrocytes by H19-induced demethylation of NCOR2

Failed or altered gliogenesis is a major characteristic of diffuse white matter injury in survivors of premature birth. The developmentally regulated long noncoding RNA (lncRNA) H19 inhibits S-adenosylhomocysteine hydrolase (SAHH) and contributes to methylation of diverse cellular components, such as DNA, RNA, proteins, lipids, and neurotransmitters. We showed that the pregnancy-derived synthetic PreImplantation Factor (sPIF) induces expression of the nuclear receptor corepressor 2 (NCOR2) via H19/SAHH-mediated DNA demethylation. In turn, NCOR2 affects oligodendrocyte differentiation markers. Accordingly, after hypoxic-ischemic brain injury in rodents, myelin protection and oligodendrocytes' fate are in part modulated by sPIF and H19. Our results revealed an unexpected mechanism of the H19/SAHH axis underlying myelin preservation during brain recovery and its use in treating neurodegenerative diseases can be envisioned.

Endometrial receptivity and pregnancy outcome

Human implantation is a highly complex and multifactorial process. Successful implantation requires the presence of a healthy embryo, a receptive endometrium, and a synchronized molecular dialogue between the two, as well as immune tolerance/protection from the host. The endometrial receptivity refers to a hormonally limited period in which the endometrial tissue acquires a transient functional status allowing blastocyst implantation and pregnancy initiation. Global knowledge of endometrial receptivity grew up in recent years. Improvements in genetics, new biomarkers, noninvasive methods, new advanced techniques (Endometrial receptivity assay - the ERA system, proteomic analysis) offer the possibility to evaluate the endometrial status and to manage patients with infertility problems, especially women undergoing assisted reproductive treatment. This overview reports the most relevant knowledge and recent advances in the study of implantation processes from the perspective of the endometrium, often considered as being the main barrier for a successful pregnancy initiation. Endometrial receptivity is a topic of great interest and further studies are needed for the early identification of endometrial abnormalities and the discovery of new strategies for increasing the chance for the establishment of pregnancy.

Synthetic PreImplantation Factor (sPIF) reduces inflammation and prevents preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality and spontaneous PTB is a major contributor. The preceding inflammation/infection contributes not only to spontaneous PTB but is associated with neonatal morbidities including impaired brain development. Therefore, control of exaggerated immune response during pregnancy is an attractive strategy. A potential candidate is synthetic PreImplantation Factor (sPIF) as sPIF prevents inflammatory induced fetal loss and has neuroprotective properties. Here, we tested maternal sPIF prophylaxis in pregnant mice subjected to a lipopolysaccharides (LPS) insult, which results in PTB. Additionally, we evaluated sPIF effects in placental and microglial cell lines. Maternal sPIF application reduced the LPS induced PTB rate significantly. Consequently, sPIF reduced microglial activation (Iba-1 positive cells) and preserved neuronal migration (Cux-2 positive cells) in fetal brains. In fetal brain lysates sPIF decreased IL-6 and INFγ concentrations. In-vitro, sPIF reduced Iba1 and TNFα expression in microglial cells and reduced the expression of pro-apoptotic (Bad and Bax) and inflammatory (IL-6 and NLRP4) genes in placental cell lines. Together, maternal sPIF prophylaxis prevents PTB in part by controlling exaggerated immune response. Given the sPIF`FDA Fast Track approval in non-pregnant subjects, we envision sPIF therapy in pregnancy.

PreImplantation Factor immunohistochemical expression correlates with prostate cancer aggressiveness

BACKGROUND

The PreImplantation Factor (PIF)-a peptide secreted by viable embryos-exerts autotrophic protective effects, promotes endometrial receptivity and controls trophoblast invasion. Synthetic PIF (sPIF) has both immune-protective and regenerative properties, and reduces oxidative stress and protein misfolding. PIF is detected by immunohistochemistry (IHC) in hyperplastic endometriotic lesions and advanced uterine cancer. sPIF reduces graft-versus-host disease while maintaining a graft-versus-leukemia effect.

METHODS

PIF detection in prostate cancer was assessed in 50 human prostate samples following radical prostatectomy using tumor-microarray-based IHC correlating PIF immune staining with Gleason score (GS) and cancer aggressiveness.

RESULTS

PIF was detected in moderate-to-high risk prostate cancer (GS 4+3 and beyond, prognostic groups 3 to 5). In prostate cancer (GS (WHO Grade Group (GG)5), PIF was detected in 50% of cases; in prostate cancer (GS 4+4 GG4), PIF was observed in 62.5% of cases; in prostate cancer (GS 4+3 GG3), PIF immunostaining was observed in 57.1% of cases. In prostate cancer, (GS 3+4 GG2) and (GS 3+3 GG1) cases where PIF staining was negative to weak, membranous staining was observed in 20% of cases (staining pattern considered negative). High-grade prostate intraepithelial neoplasia PIF positive stain in 28.57% of cases (6 of 21) was observed. In contrast, PIF was not detected in normal prostate glands. Importantly, sPIF added to the PC3 cell line alone or combined with prostate cancer fibroblast feeder-cells did not affect proliferation. Only when peripheral blood mononuclear cells were added to the culture, a minor increase in cell proliferation was noted, reflecting local proliferation control.

CONCLUSIONS

Collectively, PIF assessment could be a valuable, simple-to-use immunohistochemical biomarker to evaluate aggressiveness/prognosis in specimens from prostate cancer patients.

Preimplantation Factor (PIF): a peptide with various functions

Preimplantation Factor (PIF) is a novel fifteen amino acid linear peptide (MVRIKPGSANKPSDD), which has different biological functions in mammalian species e.g. its role in neuron restoration, pregnancy and related disorders, and also in autoimmune diseases. Since all clinical studies have shown that PIF has both local and systemic effects, it can be considered as an integrated therapy for the treatment of inflammation conditions, along with the prevention of advanced disease. The synthetic PIF (sPIF) analog is a good representative of native PIF action, and it regulates peripheral immune cells to achieve endurance without immune suppression - an effective agent in nonpregnant autoimmune models. This study provides information, from evidence-based studies so far about PIF’s different functional aspects.

Promoting Roles of Embryonic Signals in Embryo Implantation and Placentation in Cooperation with Endocrine and Immune Systems

Embryo implantation in the uterus is an essential process for successful pregnancy in mammals. In general, the endocrine system induces sufficient embryo receptivity in the endometrium, where adhesion-promoting molecules increase and adhesion-inhibitory molecules decrease. Although the precise mechanisms remain unknown, it is widely accepted that maternal–embryo communications, including embryonic signals, improve the receptive ability of the sex steroid hormone-primed endometrium. The embryo may utilize repulsive forces produced by an Eph–ephrin system for its timely attachment to and subsequent invasion through the endometrial epithelial layer. Importantly, the embryonic signals are considered to act on maternal immune cells to induce immune tolerance. They also elicit local inflammation that promotes endometrial differentiation and maternal tissue remodeling during embryo implantation and placentation. Additional clarification of the immune control mechanisms by embryonic signals, such as human chorionic gonadotropin, pre-implantation factor, zona pellucida degradation products, and laeverin, will aid in the further development of immunotherapy to minimize implantation failure in the future.

Randomized, Double-Blind, Placebo-Controlled, Single Ascending Dose Trial of Synthetic Preimplantation Factor in Autoimmune Hepatitis

Preimplantation factor (PIF) is an evolutionary conserved peptide secreted by viable embryos which promotes maternal tolerance without immune suppression. Synthetic PIF (sPIF) replicates native peptide activity. The aim of this study was to conduct the first‐in‐human trial of the safety, tolerability, and pharmacokinetics of sPIF in patients with autoimmune hepatitis (AIH). We performed a randomized, double‐blind, placebo‐controlled, prospective phase I clinical trial. Patients were adults with documented AIH with compensated chronic liver disease. Diagnosis of AIH was confirmed by either a pretreatment International Criteria for the Diagnosis of AIH score of 15 or more, or a posttreatment score of 17 or more. Patients were divided into three dosing cohorts (0.1, 0.5, or 1.0 mg/kg) of 6 patients in each group. Three patients in each group had normal liver tests and 3 patients had abnormal liver tests. They were randomized to receive a single, subcutaneous dose of either sPIF or a matching placebo. Eighteen patients were enrolled, and all successfully completed the trial. There were no clinically significant adverse events and all doses were well tolerated. Ascending doses of sPIF produced a linear increase in the respective serum levels with a half‐life of 90 minutes. There were no grade 2, 3 or 4 laboratory abnormalities. No patient developed detectable anti‐sPIF antibodies. Conclusion: This first‐in‐human trial of the safety and pharmacokinetics of sPIF (a novel biologic immune modulatory agent) demonstrated both excellent safety and tolerability. The data support further studies of multiple ascending doses of sPIF in autoimmune hepatitis and potentially other autoimmune disorders.

PreImplantation factor (PIF) therapy provides comprehensive protection against radiation induced pathologies

Acute Radiation Syndrome (ARS) may lead to cancer and death and has few effective countermeasures. Efficacy of synthetic PIF treatment was demonstrated in preclinical autoimmune and transplantation models. PIF protected against inflammation and mortality following lethal irradiation in allogeneic bone marrow transplant (BMT) model. Herein, we demonstrate that PIF imparts comprehensive local and systemic protection against lethal and sub-lethal ARS in murine models. PIF treatment 2 h after lethal irradiation led to 100% survival and global hematopoietic recovery at 2 weeks after therapy. At 24 h after irradiation PIF restored hematopoiesis in a semi-allogeneic BMT model. PIF-preconditioning provided improved long-term engraftment. The direct effect of PIF on bone marrow cells was also demonstrated in vitro: PIF promoted pre-B cell differentiation and increased immunoregulatory properties of BM-derived mesenchymal stromal cells. PIF treatment also improved hematopoietic recovery and reduced systemic inflammatory cytokine production after sub-lethal radiation exposure. Here, PIF also prevented colonic crypt and basal membrane damage coupled with reduced nitric oxide synthetase (iNOS) and increased (B7h1) expression. Global upper GI gene pathway analysis revealed PIF's involvement in protein-RNA interactions, mitochondrial oxidative pathways, and responses to cellular stress. Some effects may be attributed to PIF's influence on macrophage differentiation and function. PIF demonstrated a regulatory effect on irradiated macrophages and on classically activated M1 macrophages, reducing inflammatory gene expression (iNOS, Cox2), promoting protective (Arg1) gene expression and inducing pro-tolerance cytokine secretion. Notably, synthetic PIF is stable for long-term field use. Overall, clinical investigation of PIF for comprehensive ARS protection is warranted.

Allogeneic ovarian transplantation using immunomodulator preimplantation factor (PIF) as monotherapy restored ovarian function in olive baboon

PURPOSE

Allogeneic ovarian transplantation may be an alternative in the future to oocyte donation in women with premature ovarian failure. The objectives of this study were to (a) evaluate allotransplantation feasibility for restoration of ovarian function and (b) assess efficacy of synthetic preimplantation factor (PIF) monotherapy as sole immune-acceptance regimen.

METHODS

This is an experimental animal study using non-human primates (Papio anubis). Allogeneic orthotopic ovarian tissue transplantation was performed in two female olive baboons. PIF was administered as a monotherapy to prevent immune rejection and achieve transplant maintenance and function. Subjects underwent bilateral oophorectomy followed by cross-transplantation of prepared ovarian cortex. Postoperatively, subjects were monitored for clinical and biochemical signs of graft rejection and return of function. Weekly blood samples were obtained to monitor graft acceptance and endocrine function restoration.

RESULTS

Postoperatively, there were no clinical signs of rejection. Laboratory parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine) did not indicate organ rejection at any stage of the experiment. Initially, significant loss of follicles was noticed after grafting and serum follicle-stimulating hormone (FSH) and E2 levels were consistent with ovarian failure. Seven months after transplantation, one animal exhibited recurrence of ovarian endocrine function (perineal swelling, E2 rise, FSH decrease, and return of menstruation).

CONCLUSIONS

Organ rejection after allogeneic ovarian transplantation was prevented using PIF as monotherapy for the first time and no side effects were recorded. The study suggests the clinical feasibility of ovarian allotransplantation to obtain ovarian function.

Synthetic PreImplantation Factor (PIF) prevents fetal loss by modulating LPS induced inflammatory response

Maternal control of inflammation is essential during pregnancy and an exaggerated response is one of the underlying causes of fetal loss. Inflammatory response is mediated by multiple factors and Toll-like receptors (TLRs) are central. Activation of TLRs results in NALP-3 mediated assembly of apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 into the inflammasome and production of pro-inflammatory cytokines IL-1β and IL-18. Given that preventing measures are lacking, we investigated PreImplantation Factor (PIF) as therapeutic option as PIF modulates Inflammation in pregnancy. Additionally, synthetic PIF (PIF analog) protects against multiple immune disorders. We used a LPS induced murine model of fetal loss and synthetic PIF reduced this fetal loss and increased the embryo weight significantly. We detected increased PIF expression in the placentae after LPS insult. The LPS induced serum and placenta cytokines were abolished by synthetic PIF treatment and importantly synthetic PIF modulated key members of inflammasome complex NALP-3, ASC, and caspase-1 as well. In conclusion our results indicate that synthetic PIF protects against LPS induced fetal loss, likely through modulation of inflammatory response especially the inflammasome complex. Given that synthetic PIF is currently tested in autoimmune diseases of non-pregnant subjects (clinicaltrials.gov, NCT02239562), therapeutic approach during pregnancy can be envisioned.

PIF* promotes brain re-myelination locally while regulating systemic inflammation- clinically relevant multiple sclerosis M.smegmatis model

Neurologic disease diagnosis and treatment is challenging. Multiple Sclerosis (MS) is a demyelinating autoimmune disease with few clinical forms and uncertain etiology. Current studies suggest that it is likely caused by infection(s) triggering a systemic immune response resulting in antigen/non-antigen-related autoimmune response in central nervous system (CNS). New therapeutic approaches are needed. Secreted by viable embryos, PreImplantation Factor (PIF) possesses a local and systemic immunity regulatory role. Synthetic PIF (PIF) duplicates endogenous peptide's protective effect in pre-clinical autoimmune and transplantation models. PIF protects against brain hypoxia-ischemia by directly targeting microglia and neurons. In chronic experimental autoimmune encephalitis (EAE) model PIF reverses paralysis while promoting neural repair. Herein we report that PIF directly promotes brain re-myelination and reverses paralysis in relapsing remitting EAE MS model. PIF crosses the blood-brain barrier targeting microglia. Systemically, PIF decreases pro-inflammatory IL23/IL17 cytokines, while preserving CNS-specific T-cell repertoire. Global brain gene analysis revealed that PIF regulates critical Na+/K+/Ca++ ions, amino acid and glucose transport genes expression. Further, PIF modulates oxidative stress, DNA methylation, cell cycle regulation, and protein ubiquitination while regulating multiple genes. In cultured astrocytes, PIF promotes BDNF-myelin synthesis promoter and SLC2A1 (glucose transport) while reducing deleterious E2F5, and HSP90ab1 (oxidative stress) genes expression. In cultured microglia, PIF increases anti-inflammatory IL10 while reducing pro-inflammatory IFNγ expression. Collectively, PIF promotes brain re-myelination and neuroprotection in relapsing remitting EAE MS model. Coupled with ongoing, Fast-Track FDA approved clinical trial, NCT#02239562 (immune disorder), current data supports PIF's translation for neurodegenerative disorders therapy.

Preimplantation factor is an anti-apoptotic effector in human trophoblasts involving p53 signaling pathway

From the earliest stages of gestation, embryonic-maternal interaction has a key role in a successful pregnancy. Various factors present during gestation may significantly influence this type of juxta/paracrine interaction. PreImplantation Factor (PIF) is a recently identified factor with activity at the fetomaternal interface. PIF is secreted by viable embryos and directly controls placental development by increasing the invasive capacity of human extravillous trophoblasts (EVTs). To further specify PIF's role in the human placenta, we analyzed the genome-wide expression profile of the EVT in the presence of a synthetic PIF analog (sPIF). We found that sPIF exposure altered several pathways related to p53 signaling, survival and the immune response. Functional assays revealed that sPIF acts through the p53 pathway to reduce both early and late trophoblast apoptosis. More precisely, sPIF (i) decreases the phosphorylation of p53 at Ser-15, (ii) enhances the B-cell lymphoma-2 (BCL2) expression and (iii) reduces the BCL2-associated X protein (BAX) and BCL2 homologous antagonist killer (BAK) mRNA expression levels. Furthermore, invalidation experiments of TP53 allowed us to demonstrate that PIF's effects on placental apoptosis seemed to be essentially mediated by this gene. We have clearly shown that p53 and sPIF pathways could interact in human trophoblast and thus promotes cell survival. Furthermore, sPIF was found to regulate a gene network related to immune tolerance in the EVT, which emphasizes the beneficial effect of this peptide on the human placenta. Finally, the PIF protein levels in placentas from pregnancies affected by preeclampsia or intra-uterine growth restriction were significantly lower than in gestational age-matched control placentas. Taken as a whole, our results suggest that sPIF protects the EVT's functional status through a variety of mechanisms. Clinical application of sPIF in the treatment of disorders of early pregnancy can be envisioned.

PreImplantation factor (PIF*) regulates systemic immunity and targets protective regulatory and cytoskeleton proteins

Secreted by viable embryos, PIF is expressed by the placenta and found in maternal circulation. It promotes implantation and trophoblast invasion, achieving systemic immune homeostasis. Synthetic PIF successfully transposes endogenous PIF features to non-pregnant immune and transplant models. PIF affects innate and activated PBMC cytokines and genes expression. We report that PIF targets similar proteins in CD14+, CD4+ and CD8+ cells instigating integrated immune regulation. PIF-affinity chromatography followed by mass-spectrometry, pathway and heatmap analysis reveals that SET-apoptosis inhibitor, vimentin, myosin-9 and calmodulin are pivotal for immune regulation. PIF acts on macrophages down-stream of LPS (lipopolysaccharide-bacterial antigen) CD14/TLR4/MD2 complex, targeting myosin-9, thymosin-α1 and 14-3-3eta. PIF mainly targets platelet aggregation in CD4+, and skeletal proteins in CD8+ cells. Pathway analysis demonstrates that PIF targets and regulates SET, tubulin, actin-b, and S100 genes expression. PIF targets systemic immunity and has a short circulating half-life. Collectively, PIF targets identified; protective, immune regulatory and cytoskeleton proteins reveal mechanisms involved in the observed efficacy against immune disorders.

PreImplantation Factor (PIF*) endogenously prevents preeclampsia: Promotes trophoblast invasion and reduces oxidative stress

Preeclampsia is a unique pregnancy disorder whose patho-physiology is initiated early in gestation, while clinical manifestations typically occur in mid-to-late pregnancy. Thus, prevention should optimally be initiated in early gestation. The intimate interaction between PIF, secreted early by viable embryos, and its host-mother provides insight into putative mechanisms of preeclampsia prevention. PIF is instrumental at the two critical events underlying preeclampsia. At first, shallow implantation leads to impaired placentation, oxidative stress, protein misfolding, and endothelial dysfunction. Later in gestation, hyper-oxygenation due to overflow of maternally derived oxygenated blood compromises the placenta. The first is likely involved in early preeclampsia occurrence due to reduced effectiveness of trophoblast/uterus interaction. The latter is observed with later-onset preeclampsia, caused by a breakdown in placental blood flow regulation. We reported that 1. PIF promotes implantation, endometrium receptivity, trophoblast invasion and increases pro-tolerance trophoblastic HLA-G expression and, 2. PIF protects against oxidative stress and protein misfolding, interacting with specific targets in embryo, 3. PIF regulates systemic immunity to reduce oxidative stress. Using PIF as an early preventative preeclampsia intervention could ameliorate or even prevent the disease, whose current main solution is early delivery.

PreImplantation factor (PIF*) promotes embryotrophic and neuroprotective decidual genes: effect negated by epidermal growth factor

Background

Intimate embryo-maternal interaction is paramount for pregnancy success post-implantation. The embryo follows a specific developmental timeline starting with neural system, dependent on endogenous and decidual factors. Beyond altered genetics/epigenetics, post-natal diseases may initiate at prenatal/neonatal, post-natal period, or through a continuum. Preimplantation factor (PIF) secreted by viable embryos promotes implantation and trophoblast invasion. Synthetic PIF reverses neuroinflammation in non-pregnant models. PIF targets embryo proteins that protect against oxidative stress and protein misfolding. We report of PIF’s embryotrophic role and potential to prevent developmental disorders by regulating uterine milieu at implantation and first trimester.

Methods

PIF’s effect on human implantation (human endometrial stromal cells (HESC)) and first-trimester decidua cultures (FTDC) was examined, by global gene expression (Affymetrix), disease-biomarkers ranking (GeneGo), neuro-specific genes (Ingenuity) and proteins (mass-spectrometry). PIF co-cultured epidermal growth factor (EGF) in both HESC and FTDC (Affymetrix) was evaluated.

Results

In HESC, PIF promotes neural differentiation and transmission genes (TLX2, EPHA10) while inhibiting retinoic acid receptor gene, which arrests growth. PIF promotes axon guidance and downregulates EGF-dependent neuroregulin signaling. In FTDC, PIF promotes bone morphogenetic protein pathway (SMAD1, 53-fold) and axonal guidance genes (EPH5) while inhibiting PPP2R2C, negative cell-growth regulator, involved in Alzheimer’s and amyotrophic lateral sclerosis. In HESC, PIF affects angiotensin via beta-arrestin, transforming growth factor-beta (TGF-β), notch, BMP, and wingless-int (WNT) signaling pathways that promote neurogenesis involved in childhood neurodevelopmental diseases—autism and also affected epithelial-mesenchymal transition involved in neuromuscular disorders. In FTDC, PIF upregulates neural development and hormone signaling, while downregulating genes protecting against xenobiotic response leading to connective tissue disorders.

In both HESC and FTDC, PIF affects neural development and transmission pathways. In HESC interactome, PIF promotes FUS gene, which controls genome integrity, while in FTDC, PIF upregulates STAT3 critical transcription signal. EGF abolished PIF’s effect on HESC, decreasing metalloproteinase and prolactin receptor genes, thereby interfering with decidualization, while in FTDC, EGF co-cultured with PIF reduced ZHX2, gene that regulates neural AFP secretion.

Conclusions

PIF promotes decidual trophic genes and proteins to regulate neural development. By regulating the uterine milieu, PIF may decrease embryo vulnerability to post-natal neurodevelopmental disorders. Examination of PIF-based intervention strategies used during embryogenesis to improve pregnancy prognosis and reduce post-natal vulnerability is clearly in order.

Insight into PreImplantation Factor (PIF*) mechanism for embryo protection and development: target oxidative stress and protein misfolding (PDI and HSP) through essential RIKP [corrected] binding site

Background

Endogenous PIF, upon which embryo development is dependent, is secreted only by viable mammalian embryos, and absent in non-viable ones. Synthetic PIF (sPIF) administration promotes singly cultured embryos development and protects against their demise caused by embryo-toxic serum. To identify and characterize critical sPIF-embryo protein interactions novel biochemical and bio-analytical methods were specifically devised.

Methods

FITC-PIF uptake/binding by cultured murine and equine embryos was examined and compared with scrambled FITC-PIF (control). Murine embryo (d10) lysates were fractionated by reversed-phase HPLC, fractions printed onto microarray slides and probed with Biotin-PIF, IDE and Kv1.3 antibodies, using fluorescence detection. sPIF-based affinity column was developed to extract and identify PIF-protein interactions from lysates using peptide mass spectrometry (LC/MS/MS). In silico evaluation examined binding of PIF to critical targets, using mutation analysis.

Results

PIF directly targets viable cultured embryos as compared with control peptide, which failed to bind. Multistep Biotin-PIF targets were confirmed by single-step PIF-affinity column based isolation. PIF binds protein disulfide isomerases a prolyl-4-hydroxylase β-subunit, (PDI, PDIA4, PDIA6-like) containing the antioxidant thioredoxin domain. PIF also binds protective heat shock proteins (70&90), co-chaperone, BAG-3. Remarkably, PIF targets a common RIPK site in PDI and HSP proteins. Further, single PIF amino acid mutation significantly reduced peptide-protein target bonding. PIF binds promiscuous tubulins, neuron backbones and ACTA-1,2 visceral proteins. Significant anti-IDE, while limited anti-Kv1.3b antibody-binding to Biotin-PIF positive lysates HPLC fractions were documented.

Conclusion

Collectively, data identifies PIF shared targets on PDI and HSP in the embryo. Such are known to play a critical role in protecting against oxidative stress and protein misfolding. PIF-affinity-column is a novel utilitarian method for small molecule targets direct identification. Data reveals and completes the understanding of mechanisms involved in PIF-induced autotrophic and protective effects on the embryo.

PreImplantation factor (PIF) detection in maternal circulation in early pregnancy correlates with live birth (bovine model)

BACKGROUND

Early identification of viable pregnancy is paramount for successful reproduction. Detection of specific signals from pre-implantation viable embryos in normal pregnancy circulation would indicate initiation of embryo-maternal interaction and create a continuum to accurately reflect embryo/fetal well-being post-implantation. Viable mammalian embryos secrete PreImplantation Factor (PIF), a biomarker which plays key, multi-targeted roles to promote implantation, trophoblast invasion and modulate maternal innate and adaptive immunity toward acceptance. Anti-PIF monoclonal antibody (mAb-based chemiluminescent ELISA) accurately detects PIF in singly cultured embryos media and its increased levels correlate with embryo development up to the blastocyst stage. Herein reported that PIF levels (ELISA) in early maternal serum correlate with pregnancy outcome.

METHODS

Artificially inseminated (AI) blind-coded Angus cattle (N = 21-23) serum samples (day 10,15 & 20 post-AI) with known calf birth were blindly tested, using both non-pregnant heifers (N = 30) and steer serum as negative controls. Assay properties and anti-PIF monoclonal antibody specificity were determined by examining linearity, spike and recovery experiments and testing the antibody against 234 different circulating proteins by microarray. Endogenous PIF was detected using <3 kDa filter separation followed by anti-PIF mAb-based affinity chromatography and confirmed by ELISA and HPLC. PIF expression was established in placenta using anti-PIF mAb-based IHC.

RESULTS

PIF detects viable pregnancy at day 10 post-AI with 91.3% sensitivity, reaching 100% by day 20 and correlating with live calf birth. All non-pregnant samples were PIF negative. PIF level in pregnant samples was a stringent 3 + SD higher as compared to heifers and steer sera. Assay is linear and spike and recovery data demonstrates lack of serum interference. Anti-PIF mAb is specific and does not interact with circulating proteins. Anti-PIF based affinity purification demonstrates that endogenous PIF is what ELISA detects. The early bovine placenta expresses PIF in the trophoblast layer.

CONCLUSION

Data herein documents that PIF is a specific, reliable embryo-derived biomarker conveniently detectable in early maternal circulation. PIF ELISA emerges as practical tool to detect viable early pregnancy from day 20 post-AI.

Reproduction and autoimmune disease: important translational implications from embryo–maternal interaction

Pregnancy and autoimmune disorders (ADs) coexist in a delicate balance. Whereas women are disproportionately affected by ADs – frequently occurring during reproductive years – the disease often improves during pregnancy, unless severe. However, when ADs are at an advanced stage, both mother and fetus can be severely affected. Maternal AD amelioration reduces fetal morbidity/mortality. AD improvement occurs without compromising immune tolerance for the fetus; however, it is short-lived since postpartum, flare-up frequently occurs. Consequences of pregnancy-related maternal disease can have life-long impact. Pregnancy is not an immune-suppressed state, but rather a controlled inflammatory environment with distinct local and systemic coordination. Pregnancy requires a delicate immune balance; the embryo/allograft does not cause graft-versus-host disease while the mother/host immunity is modulated without suppression. We herein critically examine the synergetic reciprocal relationship between pregnancy and ADs. We review key ADs and their current prognosis and management. Finally, we describe PreImplantation Factor, a peptide secreted by viable embryos that, beyond its essential autotrophic and proimplantation properties, regulates systemic immune response and also proved effective in nonpregnant autoimmune and transplantation models. Hence, PreImplantation Factor may have a key role in improving ADs in pregnancy, and provide a novel drug for treatment of immune disorders in general.

Expression of survivin in human oocytes and preimplantation embryos

OBJECTIVE

To determine whether [1] survivin is expressed in human oocytes and embryos; [2] embryos grown in vitro secrete survivin protein; and [3] survivin levels are correlated with embryo cleavage rates.

DESIGN

Experimental.

SETTING

University-affiliated IVF clinic.

PATIENT(S)

Couples undergoing IVF-ET cycles.

INTERVENTION(S)

Conventional reverse transcriptase-polymerase chain reaction (PCR), real-time PCR, immunohistochemistry, Western blot on oocytes, embryos and control choriocarcinoma JEG-3 cells, and ELISA analysis of conditioned culture media.

MAIN OUTCOME MEASURE(S)

Detection of survivin mRNA and protein in oocytes and preimplantation embryos and in JEG-3 cancer cells. Detection of survivin concentrations in embryo culture media.

RESULT(S)

Survivin mRNA and protein were expressed during human oocyte maturation, from germinal vesicle to metaphase II stage, and throughout embryo development, from pronuclear stage to blastocyst stage. Survivin was localized predominantly in the cytoplasm of all cells examined and in the oocytes on the chromatin of metaphase chromosomes and midbodies. Western blot analysis of human oocyte and cancer cell extracts detected a full-length (primary) survivin band of 16.5 kDa. Survivin was also detected in conditioned media samples from embryo cultures and showed a positive correlation with embryo cleavage rates.

CONCLUSION(S)

Our data have demonstrated for the first time that human oocytes/embryos not only express but also secret survivin, suggesting that survivin may play an important role in human oogenesis and embryogenesis.

PreImplantation Factor (PIF) orchestrates systemic antiinflammatory response by immune cells: effect on peripheral blood mononuclear cells

OBJECTIVE

Embryo-derived PreImplantation Factor (PIF) is essential for pregnancy immune modulation and synthetic PIF (sPIF), reverses neuroinflammation, and prevents diabetes mellitus through its immune modulatory properties. Herein, we explore sPIF's systemic effects on peripheral blood mononuclear cells (PBMCs).

STUDY DESIGN

sPIF's effects on PBMCs and subset populations from nonpregnant patients (n = 7) and male patients were evaluated by the assessment of binding characteristics, mixed lymphocyte reaction, proliferation, cytokine secretion, and associated gene expression. Data analysis was by analysis of variance (P < .05).

RESULTS

Fluorescein isothiocyanate-sPIF bound all myelomonocytic cells; binding was 30-fold up-regulated in mitogen-activated T and B cells (P < .05). sPIF decreased mixed lymphocyte reaction by 70% and blocked anti-CD3 antibody stimulated-PBMC proliferation by approximately 80% (P < .05). In naïve PBMCs, sPIF reduced interleukin (IL)-10 and -2; in activated PBMCs, sPIF increased IL-4, -5, -10, and -2, tumor necrosis factor-α, interferon-γ, and granulocyte-macrophage colony-stimulating factor (P < .05).

CONCLUSION

Physiologic concentrations of PIF exert potent systemic antiinflammatory effects on nonpregnant activated immune cells.

Preimplantation factor (PIF) promoting role in embryo implantation: increases endometrial integrin-α2β3, amphiregulin and epiregulin while reducing betacellulin expression via MAPK in decidua

BACKGROUND

Viable embryos secrete preimplantation factor (PIF), a peptide that has autocrine effects where levels correlate with cultured embryos development. sPIF (PIF synthetic analog) promotes implantation by regulating decidual-cells immunity, adhesion, apoptosis and enhances trophoblastic cell invasion. Herein sPIF priming effects on non-decidualized endometrium and decidualized-stroma are investigated, assessing elements critical for effective embryo-maternal cross-talk, prior to and at implantation.

METHODS

We tested sPIF effect on human non-pregnant endometrial epithelial and non-decidualized stroma α2β3 integrin expression (IHC and flow cytometry), comparing with scrambled PIF (PIFscr-control). We examined sPIF effect on decidualized non-pregnant human endometrial stromal cells (HESC) determining pro-inflammatory mediators expression and secretion (ELISA) and growth factors (GFs) expression (Affymetrix global gene array). We tested sPIF effect on HESC Phospho-kinases (BioPlex) and isolated kinases activity (FastKinase).

RESULTS

sPIF up-regulates α2β3 integrin expression in epithelial cells, (P < 0.05) while PIFscr had no effect. In contrast, in stromal cell cultures sPIF had no effect on the same. In HESC, sPIF up-regulates pro-inflammatory cytokines; IL8, IL1β and IL6 expression. The major increase in GRO-α, ICAM-1 and MCP-3 expression is coupled with same ligands secretion (P < 0.05). sPIF modulates in HESC GFs expression: up-regulates amphiregulin and epiregulin- critical for implantation and enhances several fibroblast growth factors (FGF) relevant for decidual function. In contrast, sPIF down-regulates major pro-proliferative ligands, betacellulin and IGF1 expression. sPIF modulatory effect on GFs is exerted by down-regulating pro-proliferative phospho-activated MAPkinases, p-MEK1 and p-ERK (P < 0.01, P < 0.04, respectively). Stress-induced p-38-MAPK (P = 0.04) and c-Jun kinase signaling involved MAPK8IP2 (-2.1 fold) expression decreased which protects against reactive oxygen species. Although pro-inflammatory p-NFkB (P = 0.06) decrease was mild, its promoter TNFRS11 expression markedly (-25-fold) decreased. In contrast, anti-proliferative phosphatases PTPRZ1 and PPP2R2C expression increased.

CONCLUSIONS

sPIF post-fertilization primes endometrial-epithelium, while during implantation creates a beneficial pro-inflammatory milieu. PIF acts by balancing decidual pro-implantation properties while controlling excessive pro-proliferative and inflammatory signals expression. Overall, PIF influences critical peri-implantation events in a sequential coordinated fashion which facilitates embryo implantation.

Preimplantation factor (PIF) analog prevents type I diabetes mellitus (TIDM) development by preserving pancreatic function in NOD mice

Preimplantation factor (PIF) is a novel embryo-secreted immunomodulatory peptide. Its synthetic analog (sPIF) modulates maternal immunity without suppression. There is an urgent need to develop agents that could prevent the development of type 1 diabetes mellitus (TIDM). Herein, we examine sPIF's preventive effect on TIDM development by using acute adoptive-transfer (ATDM) and spontaneously developing (SDM) in non-obese diabetic (NOD) murine models. Diabetes was evaluated by urinary and plasma glucose, intraperitoneal glucose tolerance test (IPGTT), pancreatic islets insulin staining by immunohistochemistry and by pancreatic proteome evaluation using mass spectrometry, followed by signal pathway analysis. Continuous administration of sPIF for 4-weeks prevents diabetes development in ATDM model in >90% of recipients demonstrated by normal IPGTT, preserved islets architecture, number, and insulin staining. (P < 0.01). sPIF effect was specific; its protective effects are not replicated by scrambled PIF (χ(2) = 0.009) control. sPIF led also to increased circulating Th2 and Th1 cytokines. In SDM model, 4-week continuous sPIF administration prevented onset of diabetes for 21 weeks post-therapy (P < 0.01). Low-dose sPIF administration for 16 weeks prevented diabetes development up to 14 weeks post-therapy, evidenced by preserved islets architecture and insulin staining. In SDM model, pancreatic proteome pathway analysis demonstrated that sPIF regulates protein traffic, prevents protein misfolding and aggregation, and reduces oxidative stress and islets apoptosis, leading to preserved insulin staining. sPIF further increased insulin receptor expression and reduced actin and tubulin proteins, thereby blocking neutrophil invasion and inflammation. Exocrine pancreatic function was also preserved. sPIF administration results in marked prevention of spontaneous and induced adoptive-transfer diabetes suggesting its potential effectiveness in treating early-stage TIDM.

PreImplantation Factor (PIF) correlates with early mammalian embryo development-bovine and murine models

BACKGROUND

PreImplantation Factor (PIF), a novel peptide secreted by viable embryos is essential for pregnancy: PIF modulates local immunity, promotes decidual pro-adhesion molecules and enhances trophoblast invasion. To determine the role of PIF in post-fertilization embryo development, we measured the peptide's concentration in the culture medium and tested endogenous PIF's potential trophic effects and direct interaction with the embryo.

METHODS

Determine PIF levels in culture medium of multiple mouse and single bovine embryos cultured up to the blastocyst stage using PIF-ELISA. Examine the inhibitory effects of anti-PIF-monoclonal antibody (mAb) added to medium on cultured mouse embryos development. Test FITC-PIF uptake by cultured bovine blastocysts using fluorescent microscopy.

RESULTS

PIF levels in mouse embryo culture medium significantly increased from the morula to the blastocyst stage (ANOVA, P = 0.01). In contrast, atretic embryos medium was similar to the medium only control. Detectable - though low - PIF levels were secreted already by 2-cell stage mouse embryos. In single bovine IVF-derived embryos, PIF levels in medium at day 3 of culture were higher than non-cleaving embryos (control) (P = 0.01) and at day 7 were higher than day 3 (P = 0.03). In non-cleaving embryos culture medium was similar to medium alone (control). Anti-PIF-mAb added to mouse embryo cultures lowered blastocyst formation rate 3-fold in a dose-dependent manner (2-way contingency table, multiple groups, X2; P = 0.01) as compared with non-specific mouse mAb, and medium alone, control. FITC-PIF was taken-up by cultured bovine blastocysts, but not by scrambled FITC-PIF (control).

CONCLUSIONS

PIF is an early embryo viability marker that has a direct supportive role on embryo development in culture. PIF-ELISA use to assess IVF embryo quality prior to transfer is warranted. Overall, our data supports PIF's endogenous self sustaining role in embryo development and the utility of PIF- ELISA to detect viable embryos in a non-invasive manner.

A genomic and proteomic investigation of the impact of preimplantation factor on human decidual cells

OBJECTIVE

Preimplantation factor (PIF) is a novel, 15 amino acid peptide, secreted by viable embryos. This study aims to elucidate PIF's effects in human endometrial stromal cells (HESC) decidualized by estrogen and progestin, which mimics the preimplantation milieu, and in first-trimester decidua cultures (FTDC).

STUDY DESIGN

HESC or FTDC were incubated with 100 nmol/L synthetic PIF or vehicle control. Global gene expression was analyzed using microarray and pathway analysis. Proteins were analyzed using quantitative mass spectrometry, and PIF binding by protein array.

RESULTS

Gene and proteomic analysis demonstrate that PIF affects immune, adhesion, and apoptotic pathways. Significant up-regulation in HESC (fold change) include: nuclear factor-k-beta activation via interleukin-1 receptor-associated kinase binding protein 1 (53); Toll-like receptor 5 (9); FK506 binding protein 15, 133kDa protein (2.3); and Down syndrome cell adhesion molecule like 1 (16). B-cell lymphoma protein 2 was down-regulated in HESC (21.1) and FTDC (27.1). Protein array demonstrates PIF interaction with intracellular targets insulin-degrading enzyme and beta-K+ channels.

CONCLUSION

PIF displays essential multitargeted effects, of regulating immunity, promoting embryo-decidual adhesion, and regulating adaptive apoptotic processes.