Low-dose aspirin can downregulate progesterone resistance and increase the expression of LIF in endometriosis during the implantation window.

AIM: Study the effect of low-dose aspirin on the endometrial receptivity in endometriosis rat models. MATERIALS AND METHODS: This study is to explore the expressions of progesterone receptor and LIF among three groups of endometriosis rat models: control group (n = 12), EMs group (n = 15), and aspirin group (n = 17). The expressions of progesterone receptor (PR), PRA, PRB, and leukemia inhibitory factor receptor (LIFR) in eutopic endometrium were determined using immunohistochemistry technology, western blot, and qRT-PCR. The levels of LIF in eutopic endometrium and serum were detected by western blot, qRT-PCR, and ELISA. RESULTS: The expressions of PR, PRA, and PRB protein were significantly increased in the eutopic endometrium after low-dose aspirin treatment, and the level of PRB mRNA was also increased while the ratio of PRA/PRB mRNA was decreased in the eutopic endometrium. The levels of LIF in eutopic endometrium and serum were increased compared with the untreated endometriosis rats. However, the expression of LIFR was not statistically different among the three groups. CONCLUSIONS: The results suggest that the low-dose aspirin treatment could downregulate progesterone resistance and increase the expression of LIF of endometriosis rats during the implantation window, which could improve endometrial receptivity and enhance the pregnant rate of endometriosis. It may provide a potential treatment method for endometriosis-related infertility.

STAT3 phosphorylation at Ser727 and Tyr705 differentially regulates the EMT-MET switch and cancer metastasis.

Epithelial-mesenchymal transition (EMT)/mesenchymal-epithelial transition (MET) processes are proposed to be a driving force of cancer metastasis. By studying metastasis in bone marrow-derived mesenchymal stem cell (BM-MSC)-driven lung cancer models, microarray time-series data analysis by systems biology approaches revealed BM-MSC-induced signaling triggers early dissemination of CD133+/CD83+ cancer stem cells (CSCs) from primary sites shortly after STAT3 activation but promotes proliferation towards secondary sites. The switch from migration to proliferation was regulated by BM-MSC-secreted LIF and activated LIFR/p-ERK/pS727-STAT3 signaling to promote early disseminated cancer cells MET and premetastatic niche formation. Then, tumor-tropic BM-MSCs circulated to primary sites and triggered CD151+/CD38+ cells acquiring EMT-associated CSC properties through IL6R/pY705-STAT3 signaling to promote tumor initiation and were also attracted by and migrated towards the premetastatic niche. In summary, STAT3 phosphorylation at tyrosine 705 and serine 727 differentially regulates the EMT-MET switch within the distinct molecular subtypes of CSCs to complete the metastatic process.

Stüve-Wiedemann syndrome: recurrent neonatal infections caused by impairment of JAK/STAT 3 pathway.

Stüve-Wiedemann syndrome (OMIM #601559) is a rare, autosomal recessive disorder characterized by skeletal dysplasia, consecutive infections, feeding difficulties and autonomic dysregulation. We present an Afro-Caribbean family with two siblings diagnosed with Stüve-Wiedemann syndrome. The underlying loss-of-function mutation in the leukemia inhibitory factor receptor gene is thought to impair proper functioning of the JAK/STAT 3 pathway. As this affects normal functioning of T-helper cells, these patients are prone to infections with uncommon pathogens as illustrated by this case.

Leukemia Inhibitory Factor Receptor Suppresses the Metastasis of Clear Cell Renal Cell Carcinoma Through Negative Regulation of the Yes-Associated Protein.

The role of leukemia inhibitory factor receptor (LIFR), which is important in the signal transduction of the interleukin-6 cytokine family, is still undefined in clear cell renal cell carcinoma (ccRCC). Thus, we examined the function and mechanism of LIFR in ccRCC. Low LIFR expression correlated with a poor prognosis and an aggressive tumor phenotype. Moreover, integrated LIFR DNA and mRNA analysis revealed that promoter methylation and copy number variation contributed to the reduced LIFR expression. LIFR knockdown increased 786-O and Caki-2 cell invasion and migration. Notably, the Hippo pathway was highlighted as a potential downstream target of LIFR, where loss of LIFR inhibited the kinase activity of the pathway and increased the intracellular Yes-associated protein (YAP) level. Conversely, YAP inhibition impaired the LIFR-silencing promotion of cell migration, invasion, and cancer stem cell marker expression. Moreover, drug sensitivity analysis and the Cancer Cell Line Encyclopedia database revealed that LIFR-deficient cells had high sensitivity to a YAP inhibitor and to two other anticancer drugs (PHA-665752, PF2341066). Our study revealed that LIFR attenuates tumor metastasis by suppressing YAP expression, suggesting that LIFR may serve as a potential target for ccRCC treatment.

Stüve-Wiedemann syndrome: LIFR and associated cytokines in clinical course and etiology.

Stüve-Wiedemann syndrome (STWS; OMIM #610559) is a rare bent-bone dysplasia that includes radiologic bone anomalies, respiratory distress, feeding difficulties, and hyperthermic episodes. STWS usually results in infant mortality, yet some STWS patients survive into and, in some cases, beyond adolescence. STWS is caused by a mutation in the leukemia inhibitory factor receptor (LIFR) gene, which is inherited in an autosomally recessive pattern. Most LIFR mutations resulting in STWS are null mutations which cause instability of the mRNA and prevent the formation of LIFR, impairing the signaling pathway. LIFR signaling usually follows the JAK/STAT3 pathway, and is initiated by several interleukin-6-type cytokines. STWS is managed on a symptomatic basis since there is no treatment currently available.

Microglia and a functional type I IFN pathway are required to counter HSV-1-driven brain lateral ventricle enlargement and encephalitis.

HSV-1 is the leading cause of sporadic viral encephalitis, with mortality rates approaching 30% despite treatment with the antiviral drug of choice, acyclovir. Permanent neurologic deficits are common in patients that survive, but the mechanism leading to this pathology is poorly understood, impeding clinical advancements in treatment to reduce CNS morbidity. Using magnetic resonance imaging and type I IFN receptor-deficient mouse chimeras, we demonstrate HSV-1 gains access to the murine brain stem and subsequently brain ependymal cells, leading to enlargement of the cerebral lateral ventricle and infection of the brain parenchyma. A similar enlargement in the lateral ventricles is found in a subpopulation of herpes simplex encephalitic patients. Associated with encephalitis is an increase in CXCL1 and CXCL10 levels in the cerebral spinal fluid, TNF-α expression in the ependymal region, and the influx of neutrophils of encephalitic mouse brains. Reduction in lateral ventricle enlargement using anti-secretory factor peptide 16 reduces mortality significantly in HSV-1-infected mice without any effect on expression of inflammatory mediators, infiltration of leukocytes, or changes in viral titer. Microglial cells but not infiltrating leukocytes or other resident glial cells or neurons are the principal source of resistance in the CNS during the first 5 d postinfection through a Toll/IL-1R domain-containing adapter inducing IFN-ß-dependent, type I IFN pathway. Our results implicate lateral ventricle enlargement as a major cause of mortality in mice and speculate such an event transpires in a subpopulation of human HSV encephalitic patients.

Leukemia inhibitory factor receptor α-chain: a potential method for acute promyeloid leukemia therapy.

Leukemia inhibitory factor (LIF) affects multiple types of leukemia cells in vitro through its functional receptor LIFR, which comprises a complex of the LIFR α-chain (LIFRα) and gp130. Researchers have recently observed that the C-terminus of the LIFRα cytoplasmic domain contains as many conserved YXXQ motifs as gp130 (C-terminal triple YXXQ motifs, LIFRα-CT3), whose free structure has been shown to be capable of activating STAT3 phosphorylation in the cytoplasm and consequently activating STAT3-related downstream molecules in the nucleus. This process can induce pathological acute myeloid leukemia (AML) or acute promyeloid leukemia (APL) cells to differentiate into mature granulocytes, simulating the LIF-related differential cascade. This process reduces or inhibits the side effects caused by toxic all-trans retinoid acid (ATRA), which has long been used as a fundamental medication for treating AML/APL in clinical practice despite its related high relapse rate. Therefore, we believe that it is possible to maximize the beneficial effects of LIF by enriching LIFRα-CT3 in AML/APL cell cytoplasm. The aims of this work were to enrich LIFRα-specific motifs in leukemia cells using molecular biological methods and evaluate the use of membrane-permeable polypeptides as a novel possible AML/APL therapy in combination with or independent of ATRA-based chemotherapy.

Leukemia inhibitory factor in rat fetal lung development: expression and functional studies.

BACKGROUND: Leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) are members of the family of the glycoprotein 130 (gp130)-type cytokines. These cytokines share gp130 as a common signal transducer, which explains why they show some functional redundancy. Recently, it was demonstrated that IL-6 promotes fetal lung branching. Additionally, LIF has been implicated in developmental processes of some branching organs. Thus, in this study LIF expression pattern and its effects on fetal rat lung morphogenesis were assessed. METHODOLOGY/PRINCIPAL FINDINGS: LIF and its subunit receptor LIFRα expression levels were evaluated by immunohistochemistry and western blot in fetal rat lungs of different gestational ages, ranging from 13.5 to 21.5 days post-conception. Throughout all gestational ages studied, LIF was constitutively expressed in pulmonary epithelium, whereas LIFRα was first mainly expressed in the mesenchyme, but after pseudoglandular stage it was also observed in epithelial cells. These results point to a LIF epithelium-mesenchyme cross-talk, which is known to be important for lung branching process. Regarding functional studies, fetal lung explants were cultured with increasing doses of LIF or LIF neutralizing antibodies during 4 days. MAPK, AKT, and STAT3 phosphorylation in the treated lung explants was analyzed. LIF supplementation significantly inhibited lung growth in spite of an increase in p44/42 phosphorylation. On the other hand, LIF inhibition significantly stimulated lung growth via p38 and Akt pathways. CONCLUSIONS/SIGNIFICANCE: The present study describes that LIF and its subunit receptor LIFRα are constitutively expressed during fetal lung development and that they have an inhibitory physiological role on fetal lung branching.

Predictive microfluidic control of regulatory ligand trajectories in individual pluripotent cells.

Local (cell-level) signaling environments, regulated by autocrine and paracrine signaling, and modulated by cell organization, are hypothesized to be fundamental stem cell fate control mechanisms used during development. It has, however, been challenging to demonstrate the impact of cell-level organization on stem cell fate control and to relate stem cell fate outcomes to autocrine and paracrine signaling. We address this fundamental problem using a combined in silico and experimental approach in which we directly manipulate, using laminar fluid flow, the local impact of endogenously secreted gp130-activating ligands and their activation of signal transducer and activator of transcription3 (STAT3) signaling in mouse embryonic stem cells (mESC). Our model analysis predicted that flow-dependent changes in autocrine and paracrine ligand binding would impact heterogeneity in cell- and colony-level STAT3 signaling activation and cause a gradient of cell fate determination along the direction of flow. Interestingly, analysis also predicted that local cell density would be inversely proportional to the degree to which endogenous secretion contributed to cell fate determination. Experimental validation using functional activation of STAT3 by secreted factors under microfluidic perfusion culture demonstrated that STAT3 activation and consequently mESC fate were manipulable by flow rate, position in the flow field, and local cell organization. As a unique demonstration of how quantitative control of autocrine and paracrine signaling can be integrated with spatial organization to elicit higher order cell fate effects, this work provides a general template to investigate organizing principles due to secreted factors.

Effects of leukemia inhibitory factor on proliferation and odontoblastic differentiation of human dental pulp cells.

INTRODUCTION: The purpose of this study was to determine whether the leukemia inhibitory factor (LIF) is expressed in human dental tissue and exerts its effect on proliferation and odontoblastic differentiation of the dental pulp cells (DPCs). METHODS: An immunohistochemical assay was used to detect the expression of LIF and leukemia inhibitory factor receptor (LIFR) in the human dental pulp. The proliferation of DPCs was examined by culturing human primary DPCs in the presence of LIF with different doses or the neutralizing antibody to LIF. Western blot was performed to assay the phosphorylation of Janus kinase 2 (Jak2) and signal transducer and activator of transcription 3 (Stat3) in the presence or absence of LIF and/or AG 490, a specific inhibitor of Jak2. The odontoblastic differentiation of DPCs was determined using the alkaline phosphatase (ALP) activity assay, quantification of bone sialoprotein (BSP) and dentin sialophosphoprotein (DSPP) gene expression, and mineralization nodule formation. RESULTS: LIF and LIFR were present in the odontoblasts and DPCs. LIF induced proliferation of DPCs, which was inhibited by the LIF neutralizing antibody and AG 490. LIF induced phosphorylation of Jak2 and Stat3 but not in the presence of the AG490. ALP activity of DPCs, in the absence or presence of mineralization induction medium, was inhibited by LIF. Furthermore, the mineralization nodule formation and the expression of BSP and DSPP were inhibited by LIF. This inhibition on differentiation was attenuated by the AG490. CONCLUSIONS: LIF and LIFR are expressed in the human dental pulp. LIF promotes the proliferation of DPCs, and the odontoblastic differentiation is inhibited via the Jak2-Stat3 signaling pathway.

Oligoadenylate synthetase/protein kinase R pathways and alphabeta TCR+ T cells are required for adenovirus vector: IFN-gamma inhibition of herpes simplex virus-1 in cornea.

An adenoviral (Ad) vector containing the murine IFN-gamma transgene (Ad:IFN-gamma) was evaluated for its capacity to inhibit HSV-1. To measure effectiveness, viral titers were analyzed in cornea and trigeminal ganglia (TG) during acute ocular HSV-1 infection. Ad:IFN-gamma potently suppressed HSV-1 replication in a dose-dependent fashion, requiring IFN-gamma receptor. Moreover, Ad:IFN-gamma was effective when delivered -72 and -24 h before infection as well as 24 h postinfection. Associated with antiviral opposition, TG from Ad:IFN-gamma-transduced mice harbored fewer T cells. Also related to T cell involvement, Ad:IFN-gamma was effective but attenuated in TG from alphabeta TCR-deficient mice. In corneas, alphabeta TCR(+) T cells were obligatory for protection against viral multiplication. Type I IFN involvement amid antiviral efficacy of Ad:IFN-gamma was further investigated because types I and II IFN pathways have synergistic anti-HSV-1 activity. Ad:IFN-gamma inhibited viral reproduction in corneas and TG from alphabeta IFNR-deficient (CD118(-/-)) mice, although viral titers were 2- to 3-fold higher in cornea and TG compared with wild-type mice. The absence of IFN-stimulated antiviral proteins, 2'-5' oligoadenylate synthetase/RNase L, and dsRNA-dependent protein kinase R completely eliminated the antiviral effectiveness of Ad:IFN-gamma. Collectively, the results demonstrate the following: 1) nonexistence of type I IFN receptor does not abolish defense of Ad:IFN-gamma against HSV-1; 2) antiviral pathways oligoadenylate synthetase-RNase L and protein kinase R are mandatory; and 3) alphabeta TCR(+) T cells are compulsory for Ad:IFN-gamma effectiveness against HSV-1 in cornea but not in TG.