Association of Circulating Antiretinal Antibodies With Clinical Outcomes in Retinitis Pigmentosa

Purpose

To determine if circulating antiretinal antibodies (ARAs) differ between patients affected by retinitis pigmentosa (RP) and control participants and to assess whether ARAs are associated with clinical outcomes in patients with RP.

Methods

Cross-sectional study involving a group of patients clinically diagnosed with RP and a control group of healthy participants. Serum autoantibodies against enolase, heat shock protein 70 (HSP70), and carbonic anhydrase II (CAII) were tested in all participants using Jess capillary Western blot. We compared ARA prevalence between the RP and control groups and investigated the association of serum ARA positivity with macular edema and vitreomacular disorders in patients affected by RP.

Results

Thirty-six patients affected by RP and a control group of 39 healthy individuals were included. Overall, at least one ARA positivity was detected in 89% and 80% of participants in the RP and control groups, respectively. We observed a similar prevalence of anti-CAII and anti-enolase ARA between patients and controls (P = 0.87 and P = 0.35, respectively). Sera from patients with RP tested positive for anti-HSP70 ARAs more frequently than those from controls (53% vs. 36%), albeit without reaching statistical significance (P = 0.29). Among the 72 eyes with RP, 25% presented with macular edema (most often bilateral) and 33% with epiretinal membrane and/or lamellar macular hole. None of the three ARAs was associated with an increased risk of any macular complications in eyes affected by RP (all P > 0.05).

Conclusions

The prevalence of circulating ARAs against enolase, HSP70, and CAII is similar between patients affected by RP and healthy individuals. Our results provide evidence against the association of ARAs with macular edema and vitreomacular interface disorders in RP.

Heparin Precursors with Reduced Anticoagulant Properties Retain Antiviral and Protective Effects That Potentiate the Efficacy of Sofosbuvir against Zika Virus Infection in Human Neural Progenitor Cells

Zika virus (ZIKV) infection during pregnancy can result in severe birth defects, such as microcephaly, as well as a range of other related health complications. Heparin, a clinical-grade anticoagulant, is shown to protect neural progenitor cells from death following ZIKV infection. Although heparin can be safely used during pregnancy, it retains off-target anticoagulant effects if directly employed against ZIKV infection. In this study, we investigated the effects of chemically modified heparin derivatives with reduced anticoagulant activities. These derivatives were used as experimental probes to explore the structure-activity relationships. Precursor fractions of porcine heparin, obtained during the manufacture of conventional pharmaceutical heparin with decreased anticoagulant activities, were also explored. Interestingly, these modified heparin derivatives and precursor fractions not only prevented cell death but also inhibited the ZIKV replication of infected neural progenitor cells grown as neurospheres. These effects were observed regardless of the specific sulfation position or overall charge. Furthermore, the combination of heparin with Sofosbuvir, an antiviral licensed for the treatment of hepatitis C (HCV) that also belongs to the same Flaviviridae family as ZIKV, showed a synergistic effect. This suggested that a combination therapy approach involving heparin precursors and Sofosbuvir could be a potential strategy for the prevention or treatment of ZIKV infections.

Potency assays and biomarkers for cell-based advanced therapy medicinal products

Advanced Therapy Medicinal Products (ATMPs) based on somatic cells expanded in vitro, with or without genetic modification, is a rapidly growing area of drug development, even more so following the marketing approval of several such products. ATMPs are produced according to Good Manufacturing Practice (GMP) in authorized laboratories. Potency assays are a fundamental aspect of the quality control of the end cell products and ideally could become useful biomarkers of efficacy in vivo. Here we summarize the state of the art with regard to potency assays used for the assessment of the quality of the major ATMPs used clinic settings. We also review the data available on biomarkers that may substitute more complex functional potency tests and predict the efficacy in vivo of these cell-based drugs.

Endogenous neural stem cells characterization using omics approaches: Current knowledge in health and disease

Neural stem cells (NSCs), an invaluable source of neuronal and glial progeny, have been widely interrogated in the last twenty years, mainly to understand their therapeutic potential. Most of the studies were performed with cells derived from pluripotent stem cells of either rodents or humans, and have mainly focused on their potential in regenerative medicine. High-throughput omics technologies, such as transcriptomics, epigenetics, proteomics, and metabolomics, which exploded in the past decade, represent a powerful tool to investigate the molecular mechanisms characterizing the heterogeneity of endogenous NSCs. The transition from bulk studies to single cell approaches brought significant insights by revealing complex system phenotypes, from the molecular to the organism level. Here, we will discuss the current literature that has been greatly enriched in the “omics era”, successfully exploring the nature and function of endogenous NSCs and the process of neurogenesis. Overall, the information obtained from omics studies of endogenous NSCs provides a sharper picture of NSCs function during neurodevelopment in healthy and in perturbed environments.

Neural stem cell transplantation in patients with progressive multiple sclerosis: an open-label, phase 1 study

Innovative pro-regenerative treatment strategies for progressive multiple sclerosis (PMS), combining neuroprotection and immunomodulation, represent an unmet need. Neural precursor cells (NPCs) transplanted in animal models of multiple sclerosis have shown preclinical efficacy by promoting neuroprotection and remyelination by releasing molecules sustaining trophic support and neural plasticity. Here we present the results of STEMS, a prospective, therapeutic exploratory, non-randomized, open-label, single-dose-finding phase 1 clinical trial ( NCT03269071 , EudraCT 2016-002020-86), performed at San Raffaele Hospital in Milan, Italy, evaluating the feasibility, safety and tolerability of intrathecally transplanted human fetal NPCs (hfNPCs) in 12 patients with PMS (with evidence of disease progression, Expanded Disability Status Scale ≥6.5, age 18-55 years, disease duration 2-20 years, without any alternative approved therapy). The safety primary outcome was reached, with no severe adverse reactions related to hfNPCs at 2-year follow-up, clearly demonstrating that hfNPC therapy in PMS is feasible, safe and tolerable. Exploratory secondary analyses showed a lower rate of brain atrophy in patients receiving the highest dosage of hfNPCs and increased cerebrospinal fluid levels of anti-inflammatory and neuroprotective molecules. Although preliminary, these results support the rationale and value of future clinical studies with the highest dose of hfNPCs in a larger cohort of patients.

CREB3L1 and CREB3L2 control Golgi remodelling during decidualization of endometrial stromal cells

Upon progesterone stimulation, Endometrial Stromal Cells (EnSCs) undergo a differentiation program into secretory cells (decidualization) to release in abundance factors crucial for embryo implantation. We previously demonstrated that decidualization requires massive reshaping of the secretory pathway and, in particular, of the Golgi complex. To decipher the underlying mechanisms, we performed a time-course transcriptomic analysis of in vitro decidualizing EnSC. Pathway analysis shows that Gene Ontology terms associated with vesicular trafficking and early secretory pathway compartments are the most represented among those enriched for upregulated genes. Among these, we identified a cluster of co-regulated genes that share CREB3L1 and CREB3L2 binding elements in their promoter regions. Indeed, both CREB3L1 and CREB3L2 transcription factors are up-regulated during decidualization. Simultaneous downregulation of CREB3L1 and CREB3L2 impairs Golgi enlargement, and causes dramatic changes in decidualizing EnSC, including Golgi fragmentation, collagen accumulation in dilated Endoplasmic Reticulum cisternae, and overall decreased protein secretion. Thus, both CREB3L1 and CREB3L2 are required for Golgi reshaping and efficient protein secretion, and, as such, for successful decidualization.

Neurogenesis and Viral Infection

Neural stem cells (NSCs) are multipotent stem cells that reside in the fetal and adult mammalian brain, which can self-renew and differentiate into neurons and supporting cells. Intrinsic and extrinsic cues, from cells in the local niche and from distant sites, stringently orchestrates the self-renewal and differentiation competence of NSCs. Ample evidence supports the important role of NSCs in neuroplasticity, aging, disease, and repair of the nervous system. Indeed, activation of NSCs or their transplantation into injured areas of the central nervous system can lead to regeneration in animal models. Viral invasion of NSCs can negatively affect neurogenesis and synaptogenesis, with consequent cell death, impairment of cell cycle progression, early differentiation, which cause neural progenitors depletion in the cortical layer of the brain. Herein, we will review the current understanding of Zika virus (ZIKV) infection of the fetal brain and the NSCs, which are the preferential population targeted by ZIKV. Furthermore, the potential neurotropic properties of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may cause direct neurological damage, will be discussed.

Profound architectural and functional readjustments of the secretory pathway in decidualization of endometrial stromal cells

Certain cell types must expand their exocytic pathway to guarantee efficiency and fidelity of protein secretion. A spectacular case is offered by decidualizing human endometrial stromal cells (EnSCs). In the midluteal phase of the menstrual cycle, progesterone stimulation induces proliferating EnSCs to differentiate into professional secretors releasing proteins essential for efficient blastocyst implantation. Here, we describe the architectural rearrangements of the secretory pathway of a human EnSC line (TERT-immortalized human endometrial stromal cells (T-HESC)). As in primary cells, decidualization entails proliferation arrest and the coordinated expansion of the entire secretory pathway without detectable activation of unfolded protein response (UPR) pathways. Decidualization proceeds also in the absence of ascorbic acid, an essential cofactor for collagen biogenesis, despite also the secretion of some proteins whose folding does not depend on vitamin C is impaired. However, even in these conditions, no overt UPR induction can be detected. Morphometric analyses reveal that the exocytic pathway does not increase relatively to the volume of the cell. Thus, differently from other cell types, abundant production is guaranteed by a coordinated increase of the cell size following arrest of proliferation.

The Emerging Role of Stem Cells in Regenerative Dentistry

Progress of modern dentistry is accelerating at a spectacular speed in the scientific, technological and clinical areas. Practical examples are the advancement in the digital field, which has guaranteed an average level of prosthetic practices for all patients, as well as other scientific developments, including research on stem cell biology. Given their plasticity, defined as the ability to differentiate into specific cell lineages with a capacity of almost unlimited self-renewal and release of trophic/immunomodulatory factors, stem cells have gained significant scientific and commercial interest in the last 15 years. Stem cells that can be isolated from various tissues of the oral cavity have emerged as attractive sources for bone and dental regeneration, mainly due to their ease of accessibility. This review will present the current understanding of emerging conceptual and technological issues of the use of stem cells to treat bone and dental loss defects. In particular, we will focus on the clinical application of stem cells, either directly isolated from oral sources or in vitro reprogrammed from somatic cells (induced pluripotent stem cells). Research aimed at further unraveling stem cell plasticity will allow to identify optimal stem cell sources and characteristics, to develop novel regenerative tools in dentistry.

Age and Sex Influence the Neuro-inflammatory Response to a Peripheral Acute LPS Challenge

Aging is associated with an exaggerated response to peripheral inflammatory challenges together with behavioral and cognitive deficits. Studies considering both age and sex remain limited, despite sex dimorphism of astrocytes and microglial cells is largely recognized. To fill this knowledge gap, we investigated the effect of a single intraperitoneal lipopolysaccharide (LPS) administration in adult and aged mice. We assessed the expression of different inflammatory mediators, and the microglial response through binding of [¹⁸F]-VC701 tracer to translocator protein (TSPO) receptors in the male and female brain. Aged female brain showed a higher pro-inflammatory response to LPS compared to adult female and to aged male, as revealed by ex vivo binding to TSPO receptors and pro-inflammatory mediator transcript levels. The highest astroglial reaction was observed in the brain of aged females. Differently to the other groups of animals, in aged males LPS challenge did not affect transcription of triggering receptor expressed on myeloid cells 2 (TREM2). In conclusion, our study shows that in the mouse’s brain the neuro-inflammatory response to an acute peripheral insult is sex- and age-dependent. Moreover, our results might set the basis for further studies aimed at identifying sex-related targets involved in the modulation of the aberrant neuro-inflammatory response that characterizes aging. This knowledge could be relevant for the treatment of conditions such as delirium and dementia.

How to Avoid a No-Deal ER Exit

Efficiency and fidelity of protein secretion are achieved thanks to the presence of different steps, located sequentially in time and space along the secretory compartment, controlling protein folding and maturation. After entering into the endoplasmic reticulum (ER), secretory proteins attain their native structure thanks to specific chaperones and enzymes. Only correctly folded molecules are allowed by quality control (QC) mechanisms to leave the ER and proceed to downstream compartments. Proteins that cannot fold properly are instead retained in the ER to be finally destined to proteasomal degradation. Exiting from the ER requires, in most cases, the use of coated vesicles, departing at the ER exit sites, which will fuse with the Golgi compartment, thus releasing their cargoes. Protein accumulation in the ER can be caused by a too stringent QC or by ineffective transport: these situations could be deleterious for the organism, due to the loss of the secreted protein, and to the cell itself, because of abnormal increase of protein concentration in the ER. In both cases, diseases can arise. In this review, we will describe the pathophysiology of protein folding and transport between the ER and the Golgi compartment.

Innate Immune Cells: Gatekeepers of Endometriotic Lesions Growth and Vascularization

Infiltration by inflammatory leukocytes is a hallmark of all forms of endometriosis. Conversely, the innate immune system plays a key role in regulating events such as cell adhesion, migration, survival and neoangiogenesis of transformed or ectopic tissue. All these features are involved, and possibly required, in the development of endometriotic lesions. Recent data suggest that infiltrating leukocytes are not a mere epiphenomenon but represent an actual requirement for the development of the disease. In this scenario, the functional plasticity of infiltrating macrophages is a key event in the origin and maintenance of endometriotic lesions: the erroneous polarization of macrophages towards cells sustaining angiogenesis and tissue remodeling represents a potential target for novel molecular therapies.

Is Delirium the Cognitive Harbinger of Frailty in Older Adults? A Review about the Existing Evidence

Frailty is a clinical syndrome defined by the age-related depletion of the individual’s homeostatic reserves, determining an increased susceptibility to stressors and disproportionate exposure to negative health changes. The physiological systems that are involved in the determination of frailty are mutually interrelated, so that when decline starts in a given system, implications may also regard the other systems. Indeed, it has been shown that the number of abnormal systems is more predictive of frailty than those of the abnormalities in any particular system. Delirium is a transient neurocognitive disorder, characterized by an acute onset and fluctuating course, inattention, cognitive dysfunction, and behavioral abnormalities, that complicates one out of five hospital admissions. Delirium is independently associated with the same negative outcomes of frailty and, like frailty, its pathogenesis is usually multifactorial, depending on complex inter-relationships between predisposing and precipitating factors. By definition, a somatic cause should be identified, or at least suspected, to diagnose delirium. Delirium and frailty potentially share multiple pathophysiologic mechanisms and pathways, meaning that they could be thought of as the two sides to the same coin. This review aims at summarizing the existing evidence, referring both to human and animal models, to postulate that delirium may represent the cognitive harbinger of a state of frailty in older persons experiencing an acute clinical event.

Fertility Preservation in Endometriosis Patients: Anti-Müllerian Hormone Is a Reliable Marker of the Ovarian Follicle Density

OBJECTIVE

To analyze the ovarian reserve via measurement of follicular density and anti-Müllerian hormone (AMH) in endometriosis patients participating to a clinical program of cortical ovarian cryopreservation.

DESIGN

Retrospective analysis of serum AMH levels and prospective investigation of ovarian follicle number.

SETTING

University Hospital.

PATIENTS

Two hundred and two women with endometriosis and 400 controls.

INTERVENTIONS

Blood samples and ovarian biopsies.

MAIN OUTCOME MEASURES

Correlation of serum AMH levels and the number of non-growing follicles in the biopsied cortical tissues in endometriosis and control subjects, including age, type of AMH kit, and the laboratory performing the analysis as covariates.

RESULTS

AMH levels were shown to decrease with age in untreated endometriosis patients (P < 1.0 × 10^-5) but they were significantly lower in endometriosis compared to controls only in patients over 36 years old (P = 2.7 × 10^-4). The AMH decrease was faster in endometriosis compared to controls (beta = 0.27, P = 4.0 × 10^-4). Primordial follicle number decreased with the reduction of AMH levels in both cases and controls (beta = 0.3; P = 0.04).

CONCLUSION

AMH is a reliable marker of ovarian reserve in endometriosis patients, and it can predict follicular density in women undergoing ovarian tissue cryopreservation.

5-Hydroxytyrosol inhibits HIV-1 replication in primary cells of the lower and upper female reproductive tract

We investigated the potential anti-HIV-1 activity of the candidate microbicide 5-hydroxytyrosol (5-HT) both in primary human cervical tissue explants (CTE), established from tissues of women undergoing histerectomy, and in endometrium-associated leukocytes (EAL). CTE were exposed to either the laboratory-adapted HIV-1_BaL or to primary viral isolates in the presence or absence of 5-HT or 3TC/lamivudine as control and were then monitored for 12 days in terms of HIV-1 p24 Gag antigen production in culture supernatants. HIV-1_BaL replication was also evaluated in EAL by reverse transcriptase (RT) activity. The highest nontoxic concentrations of 5-HT (200 and 100 μM for CTE and EAL, respectively) exerted a significant inhibitory effect on virus replication in both primary cell systems. 5-HT did not cause significant alterations of the activation profile of CD4⁺ and CD8⁺ T cells, in terms of CD4, CCR5, CD25, CD69 and HLA-DR expression, although it decreased the percentage of CD38⁺CD8⁺ T cells. Thus, 5-HT deserves consideration as a potential candidate microbicide for preventing HIV-1 transmission or curtailing its replication in the female reproductive tract.

Early upregulation of 18-kDa translocator protein in response to acute neurodegenerative damage in TREM2-deficient mice

Mutations in the TREM2 gene confer risk for Alzheimer's disease and susceptibility for Parkinson's disease (PD). We evaluated the effect of TREM2 deletion in a 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model, measuring neurodegeneration and microglia activation using a combined in vivo imaging and postmortem molecular approach. In wild-type mice, MPTP administration induced a progressive decrease of [¹¹C]FECIT uptake, culminating at day 7. Neuronal loss was accompanied by an increase of TREM2, IL-1β, and translocator protein (TSPO) transcript levels, [¹¹C]PK11195 binding and GFAP staining (from day 2), and an early and transient increase of TNF-α, Galectin-3, and Iba-1 (from day 1). In TREM2 null (TREM2^-/-) mice, MPTP similarly affected neuron viability and microglial cells, as shown by the lower level of Iba-1 staining in basal condition, and reduced increment of Iba-1, TNF-α, and IL-1β in response to MPTP. Likely to compensate for TREM2 absence, TREM2^-/- mice showed an earlier increment of [¹¹C]PK11195 binding and a significant increase of IL-4. Taken together, our data demonstrate a central role of TREM2 in the regulation of microglia response to acute neurotoxic insults and suggest a potential modulatory role of TSPO in response to immune system deficit.

The cannabinoid receptor CB1 contributes to the development of ectopic lesions in a mouse model of endometriosis

STUDY QUESTION

Does signaling via the cannabinoid (CB₁) receptor play a role in the pathogenesis of endometriosis in a mouse model?

SUMMARY ANSWER

Mice treated with a CB₁ agonist developed larger ectopic lesions, while less severe lesions developed in the absence of functional CB₁ expression.

WHAT IS KNOWN ALREADY

The expression of components of the endocannabinoid system has been demonstrated in both mouse and human uteri. CB₁ receptors are expressed in human epithelial and stromal cell lines derived from eutopic endometrium and deep infiltrating endometriosis nodules.

STUDY DESIGN, SIZE, DURATION

This was a randomized study in a mouse model of endometriosis. In a first set of experiments, mice with endometriosis were treated with the CB₁ receptor agonist methanandamide (MET) (5 mg/kg, n = 20) on Days 1-5 and 8-12. In a second set of experiments, endometriosis development was evaluated in CB₁^-/- mice and in their wild-type (WT) littermates.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometriosis-like lesions were induced in Balb/c and C57/Bl6 mice. Two weeks after disease induction, the lesions were counted, measured and either included for immunohistochemistry analysis or frozen for gene expression profiling by semi-quantitative real-time PCR. To limit the role of chance, the experiments were conducted under standardized laboratory conditions with appropriate controls.

MAIN RESULTS AND THE ROLE OF CHANCE

The lesion total volume was significantly higher in MET-treated compared with vehicle-treated mice (P < 0.05). Expression levels of mRNA for survivin, N-cadherin, integrin β1 and interleukin-6 were increased in the ectopic endometrium of MET-treated versus vehicle-treated mice (P < 0.05). CB₁^-/- recipients that received endometrial tissue fragments from CB₁^-/- donors, WT recipients that received endometrial tissue fragments from CB₁^-/- donors and CB₁^-/- recipients that received endometrial tissue fragments from WT donors all showed a significant reduction in total lesion volume and lower expression of survivin and N-cadherin compared with WT recipients receiving uterine fragments from WT donors (P < 0.05).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

We provide evidence that endocannabinoid signaling via CB₁ receptor plays a role in the development of endometriosis in a mouse model. However, the relative contribution of the CB₁-mediated signaling pathways active in inflammatory, uterine and peritoneal cells remains to be ascertained. Since the study was performed in a mouse model, the significance of the findings in the human system warrants further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

Clarifying the function and regulation of CB₁ and its molecular interactions with endogenous ligands, and how endocannabinoids levels are regulated in women with endometriosis, represent critical areas of research for the potential development of a novel medical treatment of the disease.

STUDY FUNDING/COMPETING INTERESTS

A.M.S. was supported by a fellowship from Fondazione Giorgio Pardi. The authors have no conflicts of interest to declare.

Elevated Systemic Levels of Endocannabinoids and Related Mediators Across the Menstrual Cycle in Women With Endometriosis

Cannabinoids and modulators of the endocannabinoid system affect specific mechanisms that are critical to the establishment and development of endometriosis. The aim of this study was to measure the systemic levels of endocannabinoids and related mediators in women with and without endometriosis and to investigate whether such levels correlated with endometriosis-associated pain. Plasma and endometrial biopsies were obtained from women with a laparoscopic diagnosis of endometriosis (n = 27) and no endometrial pathology (n = 29). Plasma levels of endocannabinoids (N-arachidonoylethanolamine [AEA] and 2-arachidonoylglycerol [2-AG]) and related mediators (N-oleoylethanolamine [OEA] and N-palmitoylethanolamine [PEA]), messenger RNA expression of some of their receptors (cannabinoid receptor type 1 [CB1], CB2, transient receptor potential vanilloid type [TRPV1]), and the enzymes involved in the synthesis (N-acyl-phosphatidylethanolamine-hydrolyzing phospholipase D [NAPE-PLD]) and degradation (fatty acid amide hydrolase 1 [FAAH]) of AEA, OEA, and PEA were evaluated in endometrial stromal cells. The systemic levels of AEA, 2-AG, and OEA were elevated in endometriosis in the secretory phase compared to controls. The expression of CB1 was higher in secretory phase endometrial stromal cells of controls versus endometriosis. Similar expression levels of CB2, TRPV1, NAPE-PLD, and FAAH were detected in controls and endometriosis. Patients with moderate-to-severe dysmenorrhea and dyspareunia showed higher AEA and PEA levels than those with low-to-moderate pain symptoms, respectively. The association of increased circulating AEA and 2-AG with decreased local CB1 expression in endometriosis suggests a negative feedback loop regulation, which may impair the capability of these mediators to control pain. These preliminary data suggest that the pharmacological manipulation of the action or levels of these mediators may offer an alternative option for the management of endometriosis-associated pain.

The Targeted Delivery of Interleukin 4 Inhibits Development of Endometriotic Lesions in a Mouse Model

Endometriosis is caused by the displacement of endometrium outside the uterus contributing heavily to infertility and debilitating pelvic pain. Ectopic adhesion and growth are believed to occur under the influence of a favorable hormonal environment and immunological factors. The objective of this study is to analyze the effect of a targeted therapy with an antibody-based pharmacodelivery of interleukin 4 (F8-IL4) in a mouse model of experimentally induced endometriosis. Endometriosis-like lesions were induced in Balb/c mice. The animals were treated intravenously with F8-IL4 or with untargeted IL4 (KSF-IL4). Twelve days after disease induction, the lesions were isolated. A significant reduction in the number of total lesions/mouse and in the total volume of lesions/mouse was observed in mice treated with F8-IL4 compared to controls (P = .029 and P = .006, respectively), while no difference was found between KSF-IL4-treated mice and their controls. Gene expression was evaluated by quantitative real-time polymerase chain reaction. Expression of genes involved in cell adhesion, extracellular matrix invasion, and neovascularization was significantly downregulated in F8-IL4-treated mice compared to their controls (integrin β1: P = .02; metalloproteinase [MMP] 3: P = .02; MMP9: P = .04; vascular endothelial growth factor: P = .04). Gene expression of inflammatory cytokines (tumor necrosis factor α, IL1β, IL1α, and IL6) did not vary in the ectopic lesions isolated from F8-IL4-treated mice compared to their controls. Immunohistochemistry demonstrated a significantly reduced expression of E-cadherin and β-catenin in the lesions of mice treated with F8-IL4. Our results show that the antibody-mediated targeted delivery of IL4 inhibits the development of endometriosis in a syngeneic mouse model by likely impairing adhesion, invasion, and vascularization of the ectopic endometrium.

The endometriotic tissue lining the internal surface of endometrioma: hormonal, genetic, epigenetic status, and gene expression profile

Ovarian endometriomas are found in a consistent proportion of patients with endometriosis and are associated with a more severe form of the disease. The endometriotic tissue lining the inside of the endometrioma has been extensively studied over the years mostly for the need to compare the molecular and cellular characteristics of eutopic and ectopic endometria. Several aspects of hormonal regulation, response to local inflammation, carcinogenesis, and modifications of the local environment have been investigated in order to characterize also the processes associated with peritoneal endometriosis. In this review, we have summarized the current knowledge of pathophysiology of endometrioma, with a particular focus on the cellular components lining the internal surface of the cyst in order to provide a comprehensive overview of the hormonal, genetic, epigenetic, and gene expression profiles of this essential part of the cyst.

HLA-G Orchestrates the Early Interaction of Human Trophoblasts with the Maternal Niche

Extravillous trophoblasts (EVTs) play a central role in educating maternal leukocytes, endometrial stromal and endothelial cells to generate a receptive decidual microenvironment tailored to accept the semi-allogeneic fetus. HLA-G, a non-classical HLA class I molecule endowed with immune-regulatory functions, is primarily expressed on EVTs lining the placenta and on the naturally occurring tolerogenic dendritic cells, named DC-10, which are enriched in the human first trimester decidua. Decidual DC-10 are involved in HLA-G-mediated tolerance at the maternal–fetal interface. EVTs not only establish a tolerogenic microenvironment through the interaction with maternal innate and adaptive cells but also orchestrate placenta vascular and tissue remodeling, leading to a successful pregnancy. Here, we discuss the potential implications of the HLA-G-mediated cross-talk among the cells present at the maternal–fetal interface, and its role in maintaining a positive relationship between the mother and the fetus.

The WNT/β-catenin signaling pathway and expression of survival promoting genes in luteinized granulosa cells: endometriosis as a paradigm for a dysregulated apoptosis pathway

OBJECTIVE

To analyze the WNT/β-catenin signaling pathway in luteinized granulosa cells from women with and without endometriosis in relation to cellular apoptosis.

DESIGN

Basic.

SETTING

University hospital.

PATIENT(S)

Patients with a laparoscopic diagnosis of endometriosis (n = 30) and women undergoing intracytoplasmic sperm injection for male infertility (control group n = 39).

INTERVENTION(S)

Isolation of luteinized granulosa cells.

MAIN OUTCOME MEASURE(S)

Gene expression analysis of components of the WNT/β-catenin pathway, protein expression levels of β-catenin, and cell cycle studies in luteinized granulosa cells.

RESULT(S)

Compared with luteinized granulosa cells from control women, cells derived from endometriosis patients had significantly higher transcript levels of the β-catenin-independent molecules WNT4 and WNT5a and lower levels of the β-catenin-dependent molecule WNT1. A decrease of total β-catenin as well as of its dephosphorylated active form, together with an aberrant gene expression of the downstream targets survivin and BMP4, was detected in cells from affected women. Flow cytometry analysis confirmed an enhanced apoptosis of luteinized granulosa cells from patients with endometriosis.

CONCLUSION(S)

The concomitant dysregulation of specific members of the WNT pathway and of its pivot molecule β-catenin in granulosa cells characterized by an increased apoptosis suggests that the WNT/β-catenin signaling pathway might be involved in leading to granulosa cell atresia.

Iron availability is increased in individual human ovarian follicles in close proximity to an endometrioma compared with distal ones

STUDY QUESTION

Does the iron content of an endometrioma represent a potential source of toxicity for the adjacent follicles?

SUMMARY ANSWER

The presence of an endometrioma increases iron and H/L ferritin levels, and transferrin receptor (TfR1) mRNA in individual follicles proximal to the endometrioma and is accompanied by reduced oocyte retrieval.

WHAT IS KNOWN ALREADY

Levels of free iron in endometriotic ovarian cysts are much higher than those in normal serum or in non-endometriotic ovarian cysts. The presence of an endometrioma exerts a detrimental effect on the surrounding healthy ovarian tissue as reflected by a reduced number of developing follicles and oocytes retrieved in IVF cycles.

STUDY DESIGN, SIZE, DURATION

This is a research study with prospective collection and evaluation of individual follicles (follicular fluid and luteinized granulosa cells) from the affected and the healthy ovaries of 13 women with unilateral endometrioma.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Individual follicular samples (145) were obtained from 13 women with endometriosis-related infertility undergoing IVF-ICSI procedures from May 2012 to March 2013. All women had unilateral endometrioma not previously treated with surgery; the contralateral ovary was free of endometriomas and previous surgery. The average ± SEM age was 35.36 ± 2.5 years with anti-Mullerian hormone levels of 2.03 ± 0.55 ng/ml. Follicles were classified as: (i) proximal follicles, in physical contact with the endometrioma; (ii) distal follicles, present in the affected ovary but not in close contact with the endometrioma and (iii) contralateral follicles, in the contralateral healthy ovary. Iron content was measured by the FerroZine method. H/L ferritin subunits were evaluated by specific enzyme-linked immunosorbant assays. Expression of H ferritin and TfR1 was examined by semi-quantitative RT-PCR. Oocyte retrieval rates and Day 3 embryo quality were analyzed.

MAIN RESULTS AND THE ROLE OF CHANCE

Total iron levels were higher in endometrioma-proximal follicles compared with endometrioma-distal ones (P = 0.009) and to follicles in the healthy ovary (P = 0.02). L ferritin was higher in proximal versus distal follicles (P = 0.044) or follicles from the healthy ovary (P = 0.027). H ferritin was higher in the proximal and distal follicles compared with follicles in the healthy ovary (P = 0.042 and P = 0.0067, respectively). H ferritin transcript levels in granulosa cells were higher in proximal follicles versus follicles from healthy ovary (P = 0.02). TfR1 transcript levels were higher in proximal versus distal follicles (P = 0.03) and versus follicles from the healthy ovary (P = 0.04). The oocyte retrieval rate was lower in proximal and distal follicles than in follicles from the healthy ovary (P = 0.001 and P = 0.04, respectively).

LIMITATIONS, REASONS FOR CAUTION

This is a study on a relatively small sample size and confirmation in a larger group of patients may be required. The method used to purify luteinized granulosa cells offers the best combination of purity, viability and total number of cells recovered. However, a minor contamination by CD45(+) cells (<5%) cannot be excluded.

WIDER IMPLICATIONS OF THE FINDINGS

This study represents a further in-depth analysis of the toxic influence of the endometrioma content on the surrounding follicles. We demonstrate the presence of iron-related compounds that are potentially toxic to developing ovarian follicles adjacent to the endometrioma during IVF. Our findings provide novel information that suggests that when surgical removal of the endometrioma is not the option, follicle aspiration at sites distant from the endometrioma might increase the probability of retrieving oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by Fondazione Giorgio Pardi, Milan, Italy. The authors have no competing financial interests in relation to the content of this research paper.

TRIAL REGISTRATION NUMBER

NA.

The distinguishing cellular and molecular features of the endometriotic ovarian cyst: from pathophysiology to the potential endometrioma-mediated damage to the ovary

BACKGROUND

Clinical data suggest that the presence of an ovarian endometrioma may cause per se damage to the surrounding otherwise healthy ovarian tissue. However, the basic research has so far done a limited job in trying to understand the potential detrimental effect of an endometrioma presence in the context of the ovarian physiology. We have reviewed the literature with the aim of characterizing the pathophysiology of the endometrioma focusing mostly on factors and mechanisms potentially affecting the surrounding, otherwise normal, ovarian tissue.

METHODS

Comprehensive searches of PUBMED were conducted to identify human studies published from 1991 to 2013 in the English language on the cellular and molecular characterization of the various endometrioma components.

RESULTS

An endometrioma contains free iron, reactive oxygen species (ROS), proteolytic enzymes and inflammatory molecules in concentrations from tens to hundreds of times higher than those present in peripheral blood or in other types of benign cysts. The cyst fluid causes substantial changes in the endometriotic cells that it baths from gene expression modifications to genetic mutations The physical barrier between the cyst contents and the normal ovarian tissue is a thin wall composed of the ovarian cortex itself or fibroreactive tissue. ROS potentially permeating the surrounding tissues and proteolytic substances degrading the adjacent areas are likely to cause the substitution of normal ovarian cortical tissue with fibrous tissue in which the cortex-specific stroma is reduced. The fibrosis is associated with smooth muscle metaplasia and followed by follicular loss and intraovarian vascular injury. Follicular density in tissue surrounding the endometriotic cyst was consistently shown to be significantly lower than in healthy ovaries but this pathological change does not appear to be caused by the stretching of surrounding tissues owing to the presence of a cyst.

CONCLUSIONS

There is sufficient molecular, histological and morphological evidence, in part deriving from knowledge of the pathophysiology, to support a deleterious effect of the endometrioma on the adjacent ovarian cortical tissue, independent of the mere mechanical stretching owing to its size.

Treatment with anticancer agents induces dysregulation of specific Wnt signaling pathways in human ovarian luteinized granulosa cells in vitro

Chemotherapy has been associated with premature ovarian failure and infertility in women with cancer. It is well known that anticancer drugs reduce the primordial follicle pool and harm the ovarian blood vascularization leading to ovarian atrophy. However, their mechanism of injury still remains unclear. The aim of this study was to identify the cellular mechanisms involved in the toxicity of chemotherapy drugs belonging to different classes on human ovarian luteinized granulosa cells (LGCs). Treatment with doxorubicin (DXR), paclitaxel (PC), and cisplatin (CP) affected LGCs viability by inducing apoptosis and downregulating both estrogen receptor β and follicle-stimulating hormone receptor in a dose-dependent manner. Several members of the WNT signaling pathway are expressed in granulosa cells where they regulate follicle development, ovulation, and luteinization. Here we show that treatment with DXR, PC, and CP induced upregulation of WNT4 expression, whereas WNT3 expression was downregulated by DXR and PC and upregulated by CP. Analysis of the WNT3 downstream signaling pathway showed that total β-catenin protein levels were reduced upon treatment with DXR and PC. Additionally, restoration of β-catenin signaling by lithium chloride protected LGCs from the injury induced by chemotherapy. The in vitro LGC toxicity model described might represent a tool to identify components of specific signaling pathways, such as the Wnt pathway, that can be targeted in order to limit the follicular damage caused by chemotherapy.

Bacterial sensor triggering receptor expressed on myeloid cells-2 regulates the mucosal inflammatory response

BACKGROUND AND AIMS

Triggering receptor expressed on myeloid cells (TREM)-2 is a surface receptor detected on macrophages, dendritic cells, and microglia that binds repeated anionic motifs on yeast and Gram-positive and Gram-negative bacteria. Little is known about TREM-2 expression and function in the intestine or its role in inflammatory bowel disease (IBD). We investigated the expression of TREM-2 in the intestinal lamina propria and its role in the development of colonic inflammation.

METHODS

We measured levels of TREM-2 in lamina propria mononuclear cells from surgical specimens collected from patients with IBD or cancer (controls). We analyzed the development of colitis in TREM-2 knockout and wild-type mice. Colon samples were isolated from mice and analyzed for cytokine expression, phagocytosis of bacteria, proliferation in colonic crypts, lamina propria mononuclear cell function, and T-cell activation by ovalbumin.

RESULTS

TREM-2 was virtually absent from colon samples of control patients, but levels were significantly higher in within the inflamed mucosa of patients with IBD; it was mainly expressed by CD11c(+) cells. Levels of TREM-2 increased as acute or chronic colitis was induced in mice. TREM-2 knockout mice developed less severe colitis than wild-type mice; the knockout mice lost less body weight, had a lower disease activity index, and had smaller mucosal lesions in endoscopic analysis. Colon dendritic cells from TREM-2 knockout mice produced lower levels of inflammatory cytokines and had reduced levels of bacterial killing and T-cell activation than cells from wild-type mice.

CONCLUSIONS

TREM-2 contributes to mucosal inflammation during development of colitis in mice. Levels of TREM-2 are increased within the inflamed mucosa of patients with IBD, indicating its potential as a therapeutic target.

HLA-G expressing DC-10 and CD4(+) T cells accumulate in human decidua during pregnancy

Multiple mechanisms underlie the surprising willingness of mothers to tolerate the semi-allogeneic fetal tissues during pregnancy. Chief among these is the expression of the HLA-G molecules that has been largely demonstrated to be responsible for reprogramming the local maternal immune response towards tolerance. We recently identified a subset of tolerogenic dendritic cells, DC-10 that secrete high amounts of IL-10 and express high levels of HLA-G and its ligand ILT4. DC-10 are present in the peripheral blood and are essential in inducing adaptive regulatory T cells. We investigated the presence of DC-10 and HLA-G-expressing CD4⁺ T cells in human decidua in the first trimester of pregnancy. Results showed that these cells are highly represented in human decidua as compared to the peripheral blood. This is the first report describing decidual DC-10 and CD4⁺HLA-G⁺ T cells, strongly suggesting that they may accumulate or be induced at the fetal maternal interface to promote tolerance.

An Italian association study and meta-analysis with previous GWAS confirm WNT4, CDKN2BAS and FN1 as the first identified susceptibility loci for endometriosis

BACKGROUND

Although endometriosis may benefit from primary prevention measures, the epidemiological risk factors identified are equivocal. Two genome-wide association studies (GWAS) have been conducted for endometriosis in two different ethnic populations but results are still to be replicated consistently and across various ethnicities. To confirm the association of GWAS-derived susceptibility loci, we conducted a replication Italian case-control study and a meta-analysis.

METHODS

An independent set of 305 laparoscopically-proven endometriosis patients and 2710 controls were recruited. Four SNPs-CDKN2BAS rs1333049, rs7521902 close to WNT4, rs12700667 in an inter-genic region on 7p15.2 and fibronectin 1 rs1250248-were selected for this association study.

RESULTS

Rs1333049 risk allele G frequency resulted significantly higher in endometriosis patients compared with controls (OR 1.32, 95% CI 1.11 to 1.57), confirming the role of this locus also in the Caucasian population. The meta-analysis showed that rs7521902 was associated with endometriosis at a genome-wide significance (p(meta)=2.23×10(-9)) while for rs1250248, a genome-wide significant p(meta) value of 3.89×10(-9) was detected only in association with severe forms. An epistatic interaction between rs7521902 and rs1250248 (OR 1.56, p=1.19×10(-2)) was found especially in presence of ovarian disease (OR=2.15, p=3.12×10(-4)).

CONCLUSIONS

We confirm WNT4, CDKN2BAS and FN1 as the first identified common loci for endometriosis.

The selective vitamin D receptor agonist, elocalcitol, reduces endometriosis development in a mouse model by inhibiting peritoneal inflammation

BACKGROUND

Endometriosis, which is characterized by the growth of endometrial tissue at ectopic locations as well as vascular development and inflammation, is still an unmet clinical need since an optimal drug that allows for both pain and infertility management does not exist. Since both the eutopic and the ectopic endometrium express the vitamin D receptor (VDR), and VDR agonists are endowed with anti-proliferative and anti-inflammatory properties, we evaluated the effect of elocalcitol, a VDR agonist with low calcaemic liability, in a mouse model of experimentally induced endometriosis.

METHODS AND RESULTS

Endometriosis was induced by injection of syngeneic endometrial tissue fragments into adult Balb/c female mice. After having confirmed by immunohistochemistry that endometriotic lesions developing in mice expressed VDR, the mice were administered with elocalcitol (100 μg/kg) or vehicle orally, once a day, for various durations of time. In this model, elocalcitol was able to reduce total lesion weight up to 70% upon treatment for 1 week before and 2 weeks after disease induction. Interestingly, a therapeutic effect was also observed on already established lesions. Elocalcitol was shown to reduce the capacity of mouse endometrial cells to adhere to collagen. In addition in treated mice, a decreased state of peritoneal inflammation was demonstrated by the inhibition of macrophage recruitment and inflammatory cytokine secretion.

CONCLUSIONS

The VDR agonist elocalcitol inhibits lesion development in a validated mouse model of endometriosis, and exerts a protective effect on both the implantation and organization of transferred endometrial tissue. These preliminary data in mice provide a sound rationale for further testing in primate models and eventually in humans.

Macrophages are alternatively activated in patients with endometriosis and required for growth and vascularization of lesions in a mouse model of disease

The mechanisms that sustain endometrial tissues at ectopic sites in patients with endometriosis are poorly understood. Various leukocytes, including macrophages, infiltrate endometriotic lesions. In this study, we depleted mouse macrophages by means of either clodronate liposomes or monoclonal antibodies before the injection of syngeneic endometrial tissue. In the absence of macrophages, tissue fragments adhered and implanted into the peritoneal wall, but endometriotic lesions failed to organize and develop. When we depleted macrophages after the establishment of endometriotic lesions, blood vessels failed to reach the inner layers of the lesions, which stopped growing. Macrophages from patients with endometriosis and experimental mice, but not nonendometriotic patients who underwent surgery for uterine leiomyomas or control mice, expressed markers of alternative activation. These markers included high levels of scavenger receptors, CD163 and CD206, which are involved in both the scavenging of hemoglobin with iron transfer into macrophages and the silent clearance of inflammatory molecules. Macrophages in both inflammatory liquid and ectopic lesions were equally polarized, suggesting a critical role of environmental cues in the peritoneal cavity. Adoptively transferred, alternatively activated macrophages dramatically enhanced endometriotic lesion growth in mice. Inflammatory macrophages effectively protected mice from endometriosis. Therefore, endogenous macrophages involved in tissue remodeling appear as players in the natural history of endometriosis, required for effective vascularization and ectopic lesion growth.

Identification of soluble TREM-2 in the cerebrospinal fluid and its association with multiple sclerosis and CNS inflammation

Triggering receptor expressed on myeloid cells 2 (TREM-2) is a membrane-bound receptor expressed by microglia and macrophages. Engagement of TREM-2 on these cells has been reported to reduce inflammatory responses and, in microglial cells, to promote phagocytosis. TREM-2 function is critical within the CNS, as its genetic deficiency in humans causes neurodegeneration with myelin and axonal loss. Blockade of TREM-2 worsened the mouse model for multiple sclerosis. In the present study, a soluble form of TREM-2 protein has been identified by immunoprecipitation and by ELISA. Soluble TREM-2 protein (sTREM-2) was detected in human CSF, and was compared among subjects with relapsing-remitting multiple sclerosis (RR-MS; n = 52), primary progressive multiple sclerosis (PP-MS; n = 21), other inflammatory neurologic diseases (OIND; n = 19), and non-inflammatory neurologic diseases (NIND; n = 41). Compared to NIND subjects, CSF sTREM-2 levels were significantly higher in RR-MS (P = 0.004 by ANOVA) and PP-MS (P < 0.001) subjects, as well as in OIND (P < 0.001) subjects. In contrast, levels of sTREM-2 in blood did not differ among the groups. Furthermore, TREM-2 was detected on a subset of CSF monocytes by flow cytometry, and was also highly expressed on myelin-laden macrophages in eight active demyelinating lesions from four autopsied multiple sclerosis subjects. The elevated levels of sTREM-2 in CSF of multiple sclerosis patients may inhibit the anti-inflammatory function of the membrane-bound receptor suggesting sTREM-2 to be a possible target for future therapies.

Blockade of TREM-2 exacerbates experimental autoimmune encephalomyelitis

Triggering receptor expressed on myeloid cells (TREM-2) is a membrane receptor associated with DAP12 that is expressed primarily in myeloid cells, including dendritic cells and microglia, and promotes fusion of osteoclast precursors into multinucleated cells. A rare autosomal recessive condition, Nasu-Hakola disease (NHD) is associated with loss-of-function mutations in DAP12 and TREM-2. The brain pathology observed in NHD patients suggests that disruption of the TREM-2/DAP12 pathway leads to neurodegeneration with demyelination and axonal loss. In this study, we have characterized TREM-2 protein expression on microglia using a newly produced monoclonal antibody directed against the mouse TREM-2 receptor. We report that TREM-2 expression is up-regulated in the spinal cord during both the early inflammatory and chronic phases of myelin oligodendrocyte glycoprotein (MOG)(35-55)peptide-induced experimental autoimmune encaphalomyelitis (EAE). We also demonstrate that TREM-2 is highly expressed on microglial cells in the central nervous system (CNS) during EAE and that blockade of TREM-2 during the effector phase of EAE results in disease exacerbation with more diffuse CNS inflammatory infiltrates and demyelination in the brain parenchyma. These results demonstrate a critical role for TREM-2 during inflammatory responses in the CNS.

Vitamin D reserve is higher in women with endometriosis

BACKGROUND

An immune-mediated defect in recognition and elimination of endometrial fragments refluxed in the peritoneal cavity has been hypothesized to play a crucial role in endometriosis development. Since vitamin D is an effective modulator of the immune system, we have hypothesized that the vitamin D status may have a role in the pathogenesis of endometriosis.

METHODS

Women of reproductive age selected for surgery for gynecological indications were enrolled in this prospective cohort study. Serum levels of 25-hydroxyvitamin-D(3), 1,25-dihydroxyvitamin-D(3) and Ca(2+) were assessed.

RESULTS

Eighty-seven women with endometriosis and 53 controls were recruited. Mean (+/- SD) levels of 25-hydroxyvitamin-D(3) in women with and without endometriosis were 24.9 +/- 14.8 ng/ml and 20.4 +/- 11.8, respectively (P = 0.05). The Odds Ratio (95% Confidence Interval) for endometriosis in patients with levels exceeding the 75th percentile of the serum distribution of the molecule (28.2 ng/ml) was 4.8 (1.7-13.5). A positive gradient according to the severity of the disease was also documented. A trend towards higher levels of 1,25-dihydroxyvitamin-D(3) and Ca(2+) was observed in women with endometriosis, but differences did not reach statistical significance. As expected, serum concentrations of 25-hydroxyvitamin-D(3) and 1,25-dihydroxyvitamin-D(3,) but not Ca(2+), are influenced by the season (P < 0.001, P = 0.004, P = 0.57, respectively), while levels of the three molecules did not vary according to the phase of the menstrual cycle.

CONCLUSIONS

Endometriosis is associated with higher serum levels of vitamin D.

Cutting Edge: Inhibition of the retinoid X receptor (RXR) blocks T helper 2 differentiation and prevents allergic lung inflammation

Among the many factors regulating Th cell differentiation, some nuclear hormone receptors are emerging as important players. The retinoid X receptor (RXR) functions as heterodimerization partner for a variety of nuclear hormone receptors. We show in this study that RXR is critical for Th2-mediated immunity. An RXR antagonist inhibited Th2 differentiation, resulting in reduced production of IL-4, IL-10, and IL-13, whereas IFN-gamma production was enhanced. This effect was dependent on the presence of APCs. In addition, IL-5 production was blocked directly in Th cells. In vivo, inhibition of RXR prevented experimentally induced allergic lung inflammation. Th1-mediated inflammation was not affected. Its specific role in Th2-mediated inflammation makes RXR a promising target for the development of therapies against diseases such as allergic asthma and atopic dermatitis.

Cycling and early pregnant endometrium as a site of regulated expression of the vitamin D system

In addition to its calciotropic function, the secosteroid 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), has potent anti-proliferative/immunomodulatory effects on various tissues. Consistently, the enzyme that catalyzes the synthesis of 1,25(OH)(2)D(3), 1alpha-hydroxylase (1alpha-OHase) and the vitamin D receptor have a widespread tissue distribution. Among site-specific functions, the hormone has been suggested to be involved in uterine physiology. However, molecular analysis of the vitamin D system in normal endometrium throughout the menstrual cycle as well as its regulation in the context of endometrial physiological and pathological events have received very limited attention. Thus, we have studied expression, localization and regulation of 1alpha-OHase in human cycling and early pregnant endometrium. The capacity for 1alpha-hydroxylation and the presence of vitamin D receptor in endometrial cells have also been evaluated. The functional significance of these findings has been tested by evaluating gene expression of the catabolic enzyme, vitamin D 24-hydroxylase, and of the adhesion protein, osteopontin. Finally, to verify any potential dysfunction of the vitamin D system in endometriosis, a reproductive disease characterized by immune-mediated anomalies, we have analyzed expression of 1alpha-OHase in both eutopic and ectopic endometrium of affected patients. Results obtained showed that the active form of the 1alpha-OHase gene was expressed in human endometrial stromal cells independent of the cycle phase but with a significant increase in early pregnant decidua. A similar profile was observed for the protein, which was abundantly expressed in the cytoplasm of both endometrial stroma and epithelial glands. Both cycling and early pregnant endometrial cells also expressed the vitamin D receptor. In the same cells, 1alpha-OHase mRNA levels were significantly stimulated by the pro-inflammatory cytokine interleukin (IL)-1beta (50 and 500 pg/ml) while addition of the active form of the hormone could modulate both CYP24 and osteopontin gene expression. The 1alpha-OHase gene was also expressed in ectopic endometrium and its levels were increased in proliferative phase cultures derived from patients with endometriosis. Human cycling endometrium may be included among the extrarenal sites able to synthesize vitamin D. The IL-1beta-mediated induction of 1alpha-OHase gene and the hormonal modulation of osteopontin support a role for the hormone in the immunological mechanisms underlying uterine function. Abnormalities of this system are present in endometriosis.

Modulation of the triggering receptor expressed on the myeloid cell type 1 pathway in murine septic shock

The triggering receptor expressed on myeloid cell type 1 (TREM-1) is a cell surface molecule that has been identified on both human and murine polymorphonuclear neutrophils and mature monocytes. The activation of TREM-1 in the presence of microbial components amplifies the inflammatory response and may be responsible for the hyperresponsiveness observed during the initial stage of sepsis. To investigate the effect of the modulation of the TREM-1 pathway during experimental murine sepsis, we used analogue synthetic peptides derived from the extracellular moiety of TREM-1. The TREM-1 ligand was expressed on both peritoneal and peripheral neutrophils during experimental peritonitis in mice. The TREM-1 peptides inhibited the recognition by TREM-1 of its ligand and protected endotoxinic mice from death. In septic rats, the TREM-1 peptides improved the hemodynamic status, attenuated the development of lactic acidosis, modulated the production of such proinflammatory cytokines as tumor necrosis factor alpha and interleukin-1beta, and improved survival. The protective effect of these peptides on arterial pressure could partly be explained by a decreased production of nitric oxide. These data suggest that in vivo modulation of TREM-1 might be a suitable therapeutic tool for the treatment of sepsis.

Triggering receptor expressed in myeloid cells 2 (TREM2) trafficking in microglial cells: continuous shuttling to and from the plasma membrane regulated by cell stimulation

Cell biology of triggering receptor expressed in myeloid cells 2, a receptor expressed in brain cells (microglia and possibly neurons and oligodendrocytes) which is responsible for a neurological and psychiatric genetic disease, polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy otherwise called the Nasu-Hakola disease, is still largely unknown. Using immortalized mouse N9 microglial cells we demonstrate that triggering receptor expressed in myeloid cells 2 is mostly distributed intracellularly in two pools: a deposit in the Golgi complex and a population of exocytic vesicles, distinct from endosomes and lysosomes, which is continuously translocated to, and recycled from the cell surface. Results with ionomycin and gamma-interferon, showing rapid and slow increases, respectively, of triggering receptor expressed in myeloid cells 2 surface density, documented that the exocytosis of the receptor-rich vesicles is regulated. Pulse labeling in the cold of surface triggering receptor expressed in myeloid cells 2 with its antibody (or Fab fragment) followed by chase at 37 degrees C showed internalization, with recovery of the antibody in endosomes and lysosomes. However, part of the receptor/antibody complex, internalized for up to 30 min chase, was recycled to the cell surface within 2 min of ionomycin stimulation, together with a fraction of the total biotinylated surface protein chased in parallel. The internalized receptor appears therefore to get access to exocytic organelles distinct from lysosomes which may resemble the exocytic vesicles of resting cells. These results document that, in microglial cells, the surface density of the triggering receptor expressed in myeloid cells 2 and thus, presumably, the response to its activation, is continuously adapted and can be greatly increased, even at rapid rate, as a function of cell activation.

Production of profibrotic cytokines by invariant NKT cells characterizes cirrhosis progression in chronic viral hepatitis

Invariant (inv)NKT cells are a subset of autoreactive lymphocytes that recognize endogenous lipid ligands presented by CD1d, and are suspected to regulate the host response to cell stress and tissue damage via the prompt production of cytokines. We investigated invNKT cell response during the progression of chronic viral hepatitis caused by hepatitis B or C virus infection, a major human disease characterized by a diffused hepatic necroinflammation with scarring fibrotic reaction, which can progress toward cirrhosis and cancer. Ex vivo frequency and cytokine production were determined in circulating and intrahepatic invNKT cells from controls (healthy subjects or patients with nonviral benign or malignant focal liver damage and minimal inflammatory response) or chronic viral hepatitis patients without cirrhosis, with cirrhosis, or with cirrhosis and hepatocellular carcinoma. invNKT cells increase in chronically infected livers and undergo a substantial modification in their effector functions, consisting in the production of the type 2 profibrotic IL-4 and IL-13 cytokines, which characterizes the progression of hepatic fibrosis to cirrhosis. CD1d, nearly undetectable in noncirrhotic and control livers, is strongly expressed by APCs in cirrhotic ones. Furthermore, in vitro CD1d-dependent activation of invNKT cells from healthy donors elicits IL-4 and IL-13. Together, these findings show that invNKT cells respond to the progressive liver damage caused by chronic hepatitis virus infection, and suggest that these cells, possibly triggered by the recognition of CD1d associated with viral- or stress-induced lipid ligands, contribute to the pathogenesis of cirrhosis by expressing a set of cytokines involved in the progression of fibrosis.

Triggering receptor expressed on myeloid cells: role in the diagnosis of lung infections

The triggering receptor expressed on myeloid cells (TREM)-1 is a recently described molecule, which plays an important role in myeloid cell-activated inflammatory responses. TREM-1 is expressed on blood neutrophils and monocytes, and also on alveolar macrophages, thus suggesting a potential role in lung inflammatory responses against infections. To investigate the differential expression of TREM-1 in lung infections, its levels were assessed in bronchoalveolar lavage specimens from patients with community-acquired pneumonia or tuberculosis. TREM-1 was also investigated in patients with interstitial lung diseases, as a model of noninfectious inflammatory disease of the lung. TREM-1 expression was significantly increased in lung neutrophils and in lung macrophages of patients with pneumonia (n=7; 387.9+/-61.4 and 660.5+/-18.3, respectively) compared with patients with pulmonary tuberculosis (n=7; 59.2+/-13.1 and 80.6+/-291.2) and patients with interstitial lung diseases (n=10; 91.8+/-23.3 and 123.9+/-22.8). In contrast, TREM-1 expression on peripheral blood neutrophils was no different among the three groups. In conclusion, these data suggest that triggering receptor expressed on myeloid cells-1 is selectively expressed in the lungs of patients with pneumonia caused by extracellular bacteria and not in patients with tuberculosis, providing a potential marker for differential diagnosis.

Dominance of CCL22 over CCL17 in induction of chemokine receptor CCR4 desensitization and internalization on human Th2 cells

Chemokines and their receptors play a pivotal role in controlling T cell trafficking in immunity and inflammation. Two chemokines, CCL17 and CCL22, activate the chemokine receptor CCR4, expressed on functionally distinct subsets of T cells: cutaneous leukocyte-associated antigen (CLA)+ skin-homing, T helper (Th) 2, and CD25+ T suppressor cells. Here, we compared the ability of CCL17 and CCL22 to promote CCR4 internalization as a mechanism of regulation of receptor function on human Th2 cells. We report that CCL22 is a potent and rapid inducer of CCR4 internalization, while CCL17 is not. CCR4 internalization does not require G protein coupling, while being dependent on lipid rafts integrity and clathrin-coated pits functionality. Cell surface disappearance of CCR4 is rapidly reversed upon removal of exogenous ligand by virtue of receptor recycling. CCR4 internalization leads to a loss of functional responsiveness, while recovery of surface expression leads to re-acquisition of chemotactic sensitivity of Th2 cells. The differential CCR4 desensitization and internalization reported here and the distinct expression patterns of CCL17 and CCL22 observed in vivo suggest that while CCL17 may act first on CCR4 at the endothelial surface to promote vascular recognition, CCL22 could subsequently engage the receptor within the tissue microenvironment to guide cellular localization.

Chemokines and their receptors in asthma and chronic obstructive pulmonary disease

Recruitment of inflammatory cells into the airways is a critical event that triggers and sustains the clinical manifestations of asthma and chronic obstructive pulmonary disease. Since the identification of the family of chemotactic cytokines, known as chemokines, as critical regulators of cell trafficking in the immune system, these molecules have come to the center stage in the field of inflammation and immunity. The goal of this article will be to summarize the recent developments in our understanding of the complex role that chemokines play in the pathogenesis of asthma and COPD.

Chemokine receptors in inflammation: an overview

Chemokine receptors play a key role in directing the migration of inflammatory cells into various injured or infected organs. However, migration of inflammatory cells into tissues can in itself be a cause and amplifier of tissue damage and disease, particularly in chronic autoimmune or allergic disorders. On this basis, much effort is currently devoted at the identification of molecular signals regulating the recruitment of inflammatory cells into tissues and at developing novel strategies to inhibit discrete pathways in this process. Great progress has recently been made in identification of a number of chemokine receptors involved in the process of leukocyte migration. The challenge is now to elucidate the specific contribution and involvement of the different receptors in distinct inflammatory processes and diseases and to prove that interference with any of these pathways may lead to development of novel therapeutics.

Analysis of homing receptor expression on infiltrating leukocytes in disease states

Chemokines represent a large family of polypeptides that signal through G-protein-coupled receptors and have a role in chemotaxis, leukocyte homing, inflammation, hematopoiesis, angiogenesis and tumor growth. The chemokine/chemokine receptor system acts in coordination with a complex cytokine network to elicit and direct leukocyte infiltration into the inflamed tissue. In addition to promoting movement into the inflamed tissue, the chemokine/chemokine receptor system may also activate infiltrating cells, such as neutrophils and eosinophils, and induce local damage. In recent years, the elucidation of intricate chemokine networks has led to the identification of potential target molecules for therapeutic intervention. Of considerable interest has been the role of chemokine/chemokine receptors in regulating allergic lung inflammation. In this review, techniques to study in situ expression of chemokine receptors in inflamed tissues are presented and discussed.

Increased expression of the chemokine receptor CXCR3 and its ligand CXCL10 in peripheral airways of smokers with chronic obstructive pulmonary disease

CXCR3 is a chemokine receptor preferentially expressed on lymphocytes, particularly on type-1 T-lymphocytes. Smokers who develop chronic obstructive pulmonary disease (COPD) have a chronic bronchopulmonary inflammation that is characterized by an increased infiltration of T-lymphocytes, particularly CD8(+), in the airways and lung parenchyma. To investigate the expression of CXCR3 and its ligand interferon-induced protein 10/CXCL10 in COPD, we counted the number of CXCR3(+) cells and analyzed the expression of CXCL10 in the peripheral airways of 19 patients undergoing lung resection for localized pulmonary lesions. We examined lung specimens from seven smokers with fixed airflow limitation (COPD), five smokers with normal lung function, and seven nonsmoking subjects with normal lung function. The number of CXCR3(+) cells was immunohistochemically quantified in the epithelium, in the submucosa, and in the adventitia of peripheral airways. The number of CXCR3(+) cells in the epithelium and submucosa was increased in smokers with COPD as compared with nonsmoking subjects, but not as compared with smokers with normal lung function. Immunoreactivity for the CXCR3-ligand CXCL10 was present in the bronchiolar epithelium of smokers with COPD but not in the bronchiolar epithelium of smoking and nonsmoking control subjects. Most CXCR3(+) cells coexpressed CD8 and produced interferon gamma. These findings suggest that the CXCR3/CXCL10 axis may be involved in the T cell recruitment that occurs in peripheral airways of smokers with COPD and that these T cells may have a type-1 profile.

Thiol antioxidants inhibit the formation of the interleukin-12 heterodimer: a novel mechanism for the inhibition of IL-12 production

IL-12 is a 75 kDa heterodimeric cytokine composed of two disulfide-linked subunits, p35 and p40, which plays an important role in the regulation of the immune response. We tested the hypothesis that thiol antioxidants might interfere with dimerization of the two IL-12 subunits. We thus studied the effect of reduced glutathione (GSH) and N-acetyl-cysteine (NAC) on IL-12 p75 production by human THP-1 cell stimulated with IFN-gamma and Staphylococcus aureus Cowan strain I (SAC), using ELISAs specific for IL-12 p75 or the p40 subunit. NAC and GSH, but not cystine, at concentrations of 5-10 mM inhibited production of IL-12 p75 but not of the p40 subunit. NAC did not inhibit p40 or p35 mRNA expression in dendritic cells or THP-1 cells, or NF-kappa B activation in THP-1 cells. The effect of NAC was specific for IL-12 p75, as NAC did not affect induction of MHC class II expression by IFN-gamma-stimulated THP-1 cells. IL-12 dimer formation appears to be reduced by NAC also in vivo, because pretreatment with NAC (1 g/kg, orally), before LPS injection in mice, inhibited peak IL-12 p75 serum levels without affecting those of p40. We conclude that thiol levels regulate IL-12 p75 production and that assembly of the heterodimer is a step that might represent a target for pharmacological intervention.

Unique chemotactic response profile and specific expression of chemokine receptors CCR4 and CCR8 by CD4(+)CD25(+) regulatory T cells

Chemokines dictate regional trafficking of functionally distinct T cell subsets. In rodents and humans, a unique subset of CD4(+)CD25(+) cytotoxic T lymphocyte antigen (CTLA)-4(+) regulatory T cells (Treg) has been proposed to control peripheral tolerance. However, the molecular basis of immune suppression and the trafficking properties of Treg cells are still unknown. Here, we determined the chemotactic response profile and chemokine receptor expression of human blood-borne CD4(+)CD25(+) Treg cells. These Treg cells were found to vigorously respond to several inflammatory and lymphoid chemokines. Treg cells specifically express the chemokine receptors CCR4 and CCR8 and represent a major subset of circulating CD4(+) T cells responding to the chemokines macrophage-derived chemokine (MDC)/CCL22, thymus and activation-regulated chemokine (TARC)/CCL17, I-309/CCL1, and to the virokine vMIP-I (ligands of CCR4 and CCR8). Blood-borne CD4(+) T cells that migrate in response to CCL1 and CCL22 exhibit a reduced alloproliferative response, dependent on the increased frequency of Treg cells in the migrated population. Importantly, mature dendritic cells preferentially attract Treg cells among circulating CD4(+) T cells, by secretion of CCR4 ligands CCL17 and CCL22. Overall, these results suggest that CCR4 and/or CCR8 may guide Treg cells to sites of antigen presentation in secondary lymphoid tissues and inflamed areas to attenuate T cell activation.