Expression of co-stimulatory molecules, chemokine receptors and proinflammatory cytokines in dendritic cells from normal and chronically inflamed rat testis

The presentation of self antigens by dendritic cells (DC) plays an important role in the initiation and maintenance of autoimmunity. In a model of experimental autoimmune orchitis (EAO), we have previously characterized dominant testicular autoantigens and shown an increase in DC numbers during the course of disease. In this study, we have developed a protocol for the isolation of a highly pure population of DC (∼97%) from the testis of EAO and control rats to analyse the expression of major histocompatibility complex (MHC) class II and co-stimulatory molecules (CD80, CD86), chemokine receptors (CCR2, CCR7) and cytokines (IL-10, IL-12p70, TNF-α). By flow cytometry, we observed similar percentage and intensity levels of MHC class II, CD80 and CD86 expression in testicular DC in all groups. Moreover, by real-time RT-PCR we have detected significantly higher CCR7 mRNA level in isolated testicular DC from rats with EAO compared to controls, whereas the expression of CCR2 was decreased in orchitis. Transcripts of IL-12p40 were observed in DC from all groups, whereas the expression of IL-10 and the rate limiting IL-12 subunit p35 were detectable exclusively in testicular DC from the inflamed testes. In co-culture experiments, testicular DC isolated from EAO animals significantly enhanced naïve T-cell proliferation compared with control DC. Taken together these results suggest that testicular DC in control testis is not mature and functionally tolerogenic, whereas in EAO testis, IL-12 expression and stimulation of T-cell proliferation points to a mature immunogenic state prior imminent migration to the lymph nodes to amplify immune responses against testicular antigens.Fil: Rival, Claudia. Universidad de Buenos Aires; ArgentinaFil: Guazzone, Vanesa Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: von Wulffen, Werner. University of Giessen Lung Center; AlemaniaFil: Hackstein, Holger. Institute for Clinical Immunology and Transfusion Medicine; AlemaniaFil: Schneider, Eva. Justus Liebig Universitat Giessen; AlemaniaFil: Lustig, Livia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Meinhardt A.. Justus Liebig Universitat Giessen; AlemaniaFil: Fijak, Monika. Justus Liebig Universitat Giessen; Alemani

Immune cell subtypes and their function in the testis

Immunoregulation in the testis is characterized by a balance between immuno-suppression (or immune privilege) and the ability to react to infections and inflammation. In this review, we analyze the phenotypes of the various immune cell subtypes present in the testis, and how their functions change between homeostatic and inflammatory conditions. Starting with testicular macrophages, we explore how this heterogeneous population is shaped by the testicular microenvironment to ensure immune privilege. We then describe how dendritic cells exhibit a tolerogenic status under normal conditions, but proliferate, mature and then stimulate effector T-cell expansion under inflammatory conditions. Finally, we outline the two T-cell populations in the testis: CD4+/CD8+ αβ T cells and CD4+/CD8+ Foxp3+ regulatory T cells and describe the distribution and function of mast cells. All these cells help modulate innate immunity and regulate the immune response. By improving our understanding of immune cell behavior in the testis under normal and inflammatory conditions, we will be better placed to evaluate testis impairment due to immune mechanisms in affected patients.Fil: Bhushan, Sudhanshu. Justus Liebig Universitat Giessen.; AlemaniaFil: Theas, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Guazzone, Vanesa Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Jacobo, Patricia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Wang, Ming. The First Affiliated Hospital; ChinaFil: Fijak, Monika. Justus Liebig Universitat Giessen.; AlemaniaFil: Meinhardt, Andreas. Justus Liebig Universitat Giessen.; AlemaniaFil: Lustig, Livia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentin

Pathomechanisms of autoimmune based testicular inflammation

Infection and inflammation of the male reproductive tract are relevant causes of infertility. Inflammatory damage occurs in the special immunosuppressive microenvironment of the testis, a hallmark termed testicular immune privilege, which allows tolerance to neo-antigens from developing germ cells appearing at puberty, long after the establishment of systemic immune tolerance. Experimental autoimmune orchitis (EAO) is a well-established rodent model of chronic testicular inflammation and organ specific autoimmunity that offers a valuable in vivo tool to investigate the pathological and molecular mechanisms leading to the breakdown of the testicular immune privilege. The disease is characterized by the infiltration of the interstitium by immune cells (mainly macrophages, dendritic cells, and T cells), formation of autoantibodies against testicular antigens, production of pro-inflammatory mediators such as NO, MCP1, TNFα, IL6, or activins and dysregulation of steroidogenesis with reduced levels of serum testosterone. EAO leads to sloughing of germ cells, atrophic seminiferous tubules and fibrotic remodeling, parameters all found similarly to changes in human biopsies from infertile patients with inflammatory infiltrates. Interestingly, testosterone supplementation during the course of EAO leads to expansion of the regulatory T cell population and inhibition of disease development. Knowledge of EAO pathogenesis aims to contribute to a better understanding of human testicular autoimmune disease as an essential prerequisite for improved diagnosis and treatment.Fil: Lustig, Livia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Guazzone, Vanesa Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Theas, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Pleuger, Christiane. Justus Liebig Universitat Giessen; AlemaniaFil: Jacobo, Patricia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Pérez, Cecilia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Meinhardt, Andreas. Justus Liebig Universitat Giessen.; AlemaniaFil: Fijak, Monika. Justus Liebig Universitat Giessen; Alemani

Characterization of the micro-environment of the testis that shapes the phenotype and function of testicular macrophages

Tissue-specific macrophages are important for the activation of innate immune responses and general organ homeostasis. Testicular macrophages (TM) reside in the testicular interstitial space and comprise the largest leukocyte population in the testis and are assumed to play a role in maintaining testicular immune privilege. Numerous studies have indicated that the interstitial fluid (IF) surrounding the TM has immunosuppressive properties, which may influence the TM phenotype. However, the identity of the immunosuppressive molecules present in the IF is poorly characterized. In this thesis it is shown that in the rat, IF shifts the M1 phenotype of granulocyte macrophage-colony stimulating factor induced bone marrow derived macrophages towards the M2 phenotype. M2 macrophages polarized by IF mimic the properties of TM such as increased expression of CD163, high secretion of IL-10 and low secretion of TNF-alpha. In addition, IF-polarized macrophages display immunoregulatory functions by inducing the expansion of immunosuppressive regulatory T cells. This thesis provides evidence that PGE2, PGI2, testosterone and corticosterone are important immunoregulatory molecules in the IF, playing a relevant role in determining the phenotype of TM. Except corticosterone, all of these factors are able to inhibit the NF-kB signaling pathway to suppress the production of pro-inflammatory cytokines and thus maintain an immunosuppressive microenvironment of the testis. Corticosterone was found to be the principal immunosuppressive molecule in the IF. Its receptor, the glucocorticoid receptor, was found to be present in TM immunohistochemically. In addition, TM locally produce small amounts of corticosterone, which suppress the expression of inflammatory genes and render TM refractory to inflammatory stimuli. Taken together, these results suggest that testicular corticosterone shapes the immunosuppressive function and phenotype of TM. This steroid hormone may therefore play also an important role in the establishment and maintenance of the immune privilege of the testis.Gewebsspezifische Makrophagen haben eine wichtige Funktion bei der Aktivierung angeborener Immunantworten und der Organhomeostase. Testikuläre Makrophagen (TM) befinden sich im Interstitium des Hodens und stellen die größte Leukozytenpopulation in der männlichen Gonade dar. Es wird angenommen, dass sie eine wichtige Funktion in der Aufrechterhaltung des Immunprivilegs des Hodens ausüben. Studien haben gezeigt, dass die interstitielle Flüssigkeit (IF), wleche die TM umgibt, immunsuppressive Eigenschaften aufweist, die den Phänotyp der TM beeinflussen könnten. Allerdings konnten immunsuppressive Moleküle in der IF bislang kaum charakterisiert werden. In der vorliegenden Arbeit wird für die Ratte als Modell gezeigt, dass die IF den durch Granulozyten- Makrophagen-Kolonie-stimulierenden Faktor (GM-CSF) induzierten M1 Phänotyp von Makrophagen, die aus dem Knochenmark isoliert wurden, in Richtung des M2 Phänotyps verschieben kann. IF-polarisierte M2-Makrophagen zeigen damit charakteristische Eigenschaften von TM, wie z. Bsp. erhöhte Expression von CD163, hohe Level von sezerniertem IL-10 bei geringer TNF-alpha Sekretion. Darüber hinaus zeigen IF-polarisierte Makrophagen immunoregulatorische Funktionen, indem sie die Expansion von immunsuppressiven regulatorischen T-Zellen induzieren. In dieser Studie werden erstmals auch Ergebnisse vorgestellt, die zeigen, dass PGE2, PGI2, Testosteron und Corticosteron wichtige immunregulatorische Moleküle in der IF darstellen und eine wesentliche Rolle bei der Bestimmung des TM-Phänotyps spielen. Mit Ausnahme von Corticosteron sind die genannten Faktoren in der Lage, den NF-kB-Signalweg zu hemmen, und damit die Produktion von entzündungshemmenden Zytokinen zu unterdrücken. Bei Corticosteron war der NFkB Signalweg bei der Immunsuppression nicht blockiert. Corticosteron konnte als wichtigster immunsuppressiver Faktor in der IF identifiziert werden. Dessen Rezeptor, der Glucocorticoidrezeptor, konnte in TM mittels Immunhistochemie gefunden werden. TM produzieren lokal moderate Mengen an Corticosteron, die die Expression inflammatorischer Gene unterdrücken und TM unempfindlich gegenüber entzündlichen Stimuli machen können. Zusammengenommen zeigen diese Ergebnisse, dass testikuläres Corticosteron maßgeblich für die immunsuppressive Funktion und den spezifischen Phänotyp der TM verantwortlich ist. Damit könnte das Steroidhormon auch eine wichtige Rolle bei der Etablierung und Aufrechterhaltung des Immunprivilegs im Hoden spielen

Uropathogenic Escherichia coli block MyD88-dependent and activate MyD88-independent signaling pathways in rat testicular cells.

International audienceUropathogenic Escherichia coli (UPEC) is the most common etiological cause of urogenital tract infections and represents a considerable cause of immunological male infertility. We examined TLR 1-11 expression profiles in testicular cells and the functional response to infection with UPEC. All testicular cell types expressed mRNAs for at least two TLRs and, in particular, synthesis of TLR4 was induced in testicular macrophages (TM), Sertoli cells (SC), peritubular cells (PTC), and peritoneal macrophages (PM) after UPEC exposure. Even though MyD88-dependent pathways were activated as exemplified by phosphorylation of mitogen-activated protein kinases in TM, SC, PTC, and PM and by the degradation of IkappaBalpha and the nuclear translocation of NF-kappaB in PTC and PM, treatment with UPEC did not result in secretion of the proinflammatory cytokines IL-1alpha, IL-6, and TNF-alpha in any of the investigated cells. Moreover, stimulated production of these cytokines by nonpathogenic commensal E. coli or LPS in PM was completely abolished after coincubation with UPEC. Instead, in SC, PTC, TM, and PM, UPEC exposure resulted in activation of MyD88-independent signaling as documented by nuclear transfer of IFN-related factor-3 and elevated expression of type I IFNs alpha and beta, IFN-gamma-inducible protein 10, MCP-1, and RANTES. We conclude that in this in vitro model UPEC can actively suppress MyD88-dependent signaling at different levels to prevent proinflammatory cytokine secretion by testicular cells. Thus, testicular innate immune defense is shifted to an antiviral-like MyD88-independent response

Bone Status in a Mouse Model of Experimental Autoimmune-Orchitis

Investigations in male patients with fertility disorders revealed a greater risk of osteoporosis. The rodent model of experimental autoimmune-orchitis (EAO) was established to analyze the underlying mechanisms of male infertility and causes of reduced testosterone concentration. Hence, we investigated the impact of testicular dysfunction in EAO on bone status. Male mice were immunized with testicular homogenate in adjuvant to induce EAO (n = 5). Age-matched mice were treated with adjuvant alone (adjuvant, n = 6) or remained untreated (control, n = 7). Fifty days after the first immunization specimens were harvested. Real-time reverse transcription-PCR indicated decreased bone metabolism by alkaline phosphatase and Cathepsin K as well as remodeling of cell-contacts by Connexin-43. Micro computed tomography demonstrated a loss of bone mass and mineralization. These findings were supported by histomorphometric results. Additionally, biomechanical properties of femora in a three-point bending test were significantly altered. In summary, the present study illustrates the induction of osteoporosis in the investigated mouse model. However, results suggest that the major effects on bone status were mainly caused by the complete Freund’s adjuvant rather than the autoimmune-orchitis itself. Therefore, the benefit of the EAO model to transfer laboratory findings regarding bone metabolism in context with orchitis into a clinical application is limited

Targeting high mobility group box protein 1 ameliorates testicular inflammation in experimental autoimmune orchitis.

STUDY QUESTION: Does high mobility group box protein 1 (HMGB1) regulate inflammatory reactions in a rat model of experimental autoimmune orchitis (EAO)? SUMMARY ANSWER: HMGB1 appears to be involved in regulating inflammatory reactions in testes, as HMGB1 is translocated from testicular cells during the course of EAO and blocking its action by ethyl pyruvate (EP) reduces disease progression and spermatogenic damage. WHAT IS KNOWN ALREADY: Despite its immune privileged status, the human testis is prone to inflammatory lesions associated with male factor infertility. Accumulating evidence shows that HMGB1 plays an important role in onset and progression of autoimmune diseases. STUDY DESIGN, SIZE, DURATION: This is a cross sectional and longitudinal study involving Wistar male rats immunized with testicular homogenates to induce EAO 50 (EAO50; n = 10) and 80 (EAO80; n = 10) days after first immunization. Control adjuvant animals received saline instead of testicular homogenate (n = 16). Untreated animals (n = 10) were also studied. An interventional study was performed to block the action of HMGB1 starting 20 days after first immunization in EAO animals and respective controls (n = 17). Rats were treated i.p. with EP and the effect of EP treatment on testicular pathogenesis was evaluated 30 days later. Moreover, human testicular biopsies from infertile men with focal lymphocytic infiltrates (n = 7) and sections with intact spermatogenesis (n = 6) were probed with antibodies against HMGB1. PARTICIPANTS/MATERIALS, SETTING, METHODS: Testicular RNA and protein extracts from EAO animals, EAO animals treated with EP and relevant controls were used for analysis of cytokine expression by real-time RT–PCR and enzyme-linked immunosorbent assay. HMGB1 was co-localized on rat testicular cross sections with antibodies against testicular macrophages (TM), peritubular cells (PTC) and Sertoli cells (SC). Interaction of HMGB1 and its receptors (RAGE, TLR4) as well signaling pathways after HMGB1 stimulation were studied in isolated TM, PTC and SC by proximity ligation assay and western blot, respectively. Furthermore, HMGB1 immunofluorescence on human testicular biopsies was performed. MAIN RESULTS AND THE ROLE OF CHANCE: HMGB1 was translocated from the nuclei in EAO testes and testes of infertile men with impaired spermatogenesis and lymphocytic infiltrates. Elevated HMGB1 levels were observed during late phase of EAO. In testicular somatic cells HMGB1 receptors Toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE) were differentially expressed: HMGB1-TLR4 binding was predominant in TM, while HMGB1-RAGE interaction was prevalent in SC and PTC. In support, HMGB1 triggered extracellular signal regulated kinase (ERK)1/2 and cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) activation in SC and PTC, while TM responded to HMGB1 stimulation with p38 mitogen-activated protein kinase (MAPK) and p65 nuclear factor Kappa B (NF-ĸB) phosphorylation followed by increased tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) mRNA levels. In vivo treatment of EAO animals with EP 20 days after induction of disease revealed beneficial effects, as documented by reduced disease progression and spermatogenic damage, lower macrophage numbers, as well as decreased concentrations of HMGB1 and IL-6 in the testis compared with EAO controls. LIMITATIONS, REASONS FOR CAUTION: The ability of HMGB1 to bind to a wide range of receptors makes it difficult to prevent its action by blockade of a specific receptor; therefore we applied EP, a drug preventing HMGB1 release from cells. Due to its mode of action EP decreases also the secretion of some other pro-inflammatory cytokines. Using isolated primary cells imposes limitations for cell transfection studies. As a compromise between purity and yield primary cells need to be isolated from animals of different age, which has to be considered when comparing their responses. WIDER IMPLICATIONS OF THE FINDINGS: HMGB1 could be a promising target in attenuating testicular damage caused by inflammatory reactions. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by a research grant of the University Medical Centre Giessen and Marburg to M.F. and H.-C.S. A.M., H.-C.S. and M.F. are supported by the LOEWE focus group ‘MIBIE’ (Male infertility during infection & inflammation)—an excellence initiative of the government of the German state of Hessen. The authors have nothing to disclose.Fil: Aslani, Ferial. Justus Liebig University Giessen; AlemaniaFil: Schuppe, Hans-Christian. Justus Liebig University Giessen; AlemaniaFil: Guazzone, Vanesa Anabella. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; ArgentinaFil: Bhushan, Sudhanshu. Justus Liebig University Giessen; AlemaniaFil: Wahle, Eva. Justus Liebig University Giessen; AlemaniaFil: Lochnit, Günter. Justus Liebig University Giessen; AlemaniaFil: Lustig, Livia. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; ArgentinaFil: Meinhardt, Andreas. Justus Liebig University Giessen; AlemaniaFil: Fijak, Monika. Justus Liebig University Giessen; Alemani