Toll-like receptor 4 in rat prostate: modulation by testosterone and acute bacterial infection in epithelial and stromal cells

Castration immunoregulates toll-like receptor-4 in male bladder cancer

PURPOSE

Among diverse Pattern Recognition Receptors (PRRs), Toll-like receptor-4 (TLR-4) is a key urothelial trigger for innate immune response impacting urothelial bladder carcinoma (BC). Androgen activation promotes immunotolerance, playing an immunoregulatory role by unknown mechanisms. We explored the castration impact on urothelial TLR-4 modulation in carcinogenesis and immunotherapeutic scenario.

METHODS

Intact (SHAM) versus castrated male Fisher-344 rats were evaluated in 2 scenarios: (A) Carcinogenesis: After randomization to SHAM (n = 5) and Castration (n = 5), carcinogenesis was induced by four intravesical doses of 1.5 mg/kg n-methyl-n-nitrosourea (MNU) every 15 days. (B) Treatment: After ultrasonographic confirmed MNU-induced papillary BC on week 8, rats were randomized to SHAM (n = 5) and Castration (n = 5) and offered 6 weekly intravesical treatment of 10⁶ CFU of bacillus Calmette Guerin (BCG) in 0.2 ml saline. After 15 weeks the urinary bladders underwent histopathology. Urothelial cell proliferation was measured by Ki-67 immunohistochemistry (IHC), and TLR-4 expression was quantified by IHC and WB.

RESULTS

Castration induced higher TLR-4 urothelial expression (p = 0.007) and anticarcinogenic effect with fewer urothelial tumors (60 vs. 80%) and lower urothelial cell proliferation compared to intact animals (p = 0.008). In the intravesical BCG treatment setting, castration has potentialized the BCG activation of TLR-4 (p = 0.007) with no residual in situ carcinoma compared to intact animals, suggesting the potential to amplify the BCG immune response.

CONCLUSION

To our knowledge, this is the first description of TLR-4 urothelial expression hormonal modulation. The described castration-mediated immunomodulation will help to improve the knowledge of urothelial cancer gender diversities and PRRs modulations with treatment implications.

Metabolic Hormones Modulate Macrophage Inflammatory Responses

Simple Summary

Macrophages are a type of immune cell which play an important role in the development of cancer. Obesity increases the risk of cancer and obesity also causes disruption to the normal levels of hormones that are produced to coordinate metabolism. Recent research now shows that these metabolic hormones also play important roles in macrophage immune responses and so through macrophages, disrupted metabolic hormone levels may promote cancer. This review article aims to highlight and summarise these recent findings so that the scientific community may better understand how important this new area of research is, and how these findings can be capitalised on for future scientific studies.

Abstract

Macrophages are phagocytotic leukocytes that play an important role in the innate immune response and have established roles in metabolic diseases and cancer progression. Increased adiposity in obese individuals leads to dysregulation of many hormones including those whose functions are to coordinate metabolism. Recent evidence suggests additional roles of these metabolic hormones in modulating macrophage inflammatory responses. In this review, we highlight key metabolic hormones and summarise their influence on the inflammatory response of macrophages and consider how, in turn, these hormones may influence the development of different cancer types through the modulation of macrophage functions.

Pattern recognition receptor-initiated innate immune responses in mouse prostatic epithelial cells‡

Three major pathogenic states of the prostate, including benign prostatic hyperplasia, prostate cancer, and prostatitis, are related to the local inflammation. However, the mechanisms underlying the initiation of prostate inflammation remain largely unknown. Given that the innate immune responses of the tissue-specific cells to microbial infection or autoantigens contribute to local inflammation, this study focused on pattern recognition receptor (PRR)-initiated innate immune responses in mouse prostatic epithelial cells (PECs). Primary mouse PECs abundantly expressed Toll-like receptor 3 (TLR3), TLR4, TLR5, melanoma differentiation-associated protein 5 (MDA5), and IFN-inducible protein 16 (p204 in mouse). These PRRs can be activated by their respective ligands: lipopolysaccharide (LPS) and flagellin of Gram-negative bacteria for TLR4 and TLR5, polyinosinic-polycytidylic acid (poly(I:C)) for TLR3 and MDA5, and herpes simplex virus DNA analog (HSV60) for p204. LPS and flagellin predominantly induced the expression of inflammatory cytokines, including tumor necrosis factor alpha (TNFA), interleukin 6 (IL6), chemokines monocyte chemoattractant protein-1 (MCP1), and C-X-C motif chemokine 10 (CXCL10). Poly(I:C) and HSV60 predominantly induced the expression of type 1 interferons (IFNA and IFNB) and antiviral proteins: Mx GTPase 1, 2',5'-oligoadenylate synthetase 1, and IFN-stimulated gene 15. The replication of mumps virus in PECs was inhibited by type 1 IFN signaling. These findings provide insights into the mechanisms underlying innate immune response in the prostate.

Prostate immunology: A challenging puzzle

Mucosal immunity defines the relationship of surfaces in contact with the environment and integrates diverse tissues such as epidermis, gum, nose, gut, uterus and prostate with the immune system. Although considered part of a system, each mucosa presents specific immune features beyond the barrier and secretory functions. Information regarding the mucosal immunology of the male reproductive tract and the prostate gland in particular is scarce. In this review, we approach the prostate as an epithelial barrier and as part of the mucosal immune system. Finally, we also raise a series of questions that will improve the understanding of this gland, its role in reproduction and its sensitivity/resistance to disease.

MicroRNA-155 deficiency attenuates inflammation and oxidative stress in experimental autoimmune prostatitis in a TLR4-dependent manner

To explore the mechanism of microRNA-155 (miR-155) deficiency, protecting against experimental autoimmune prostatitis (EAP) in a toll-like receptor 4 (TLR4)-dependent manner. After wild-type (WT) and miR-155^-/- mice were injected with complete Freund's adjuvant and prostate antigen to establish EAP model, half were randomly selected for injection with lipopolysaccharide (LPS, a TLR4 ligand). The following experiments were then performed: von Frey filaments, hematoxylin-eosin (HE) staining, real time quantitative polymerase chain reaction (qRT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA). And the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and the level of Malondialdehyde (MDA) were detected by corresponding kits.miR-155^-/- mice with prostatitis exhibited the attenuated pelvic tactile allodynia/hyperalgesia and the suppressed TLR4/nuclear factor-kappa B (NF-κB) pathway as compared with the WT mice with prostatitis. In addition, LPS enhanced the upregulation of miR-155 and the activation of the TLR4/NF-κB pathway in the prostatic tissues of WT mice with EAP. Furthermore, prostatitis mice had aggravated inflammation scores accompanying the increased interleukin (IL)-1β, tumor necrosis factor-α, IL-6, interferon-γ, IL-12, and MDA in prostatic tissues with the decreased IL-10, SOD and GSH-Px, and the unaltered IL-4. Compared with the mice from the WT + EAP group and the miR-155^-/- + EAP + LPS group, mice from the miR-155^-/- + EAP group had decreased inflammation and oxidative stress. miR-155 deficiency ameliorated pelvic tactile allodynia/hyperalgesia in EAP mice and improved inflammation and oxidative stress in prostatic tissues in a TLR4-dependent manner involving NF-κB activation, thereby exerting a therapeutic effect in chronic prostatitis treatment.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

Embryonic stem cell-derived exosomes inhibit doxorubicin-induced TLR4-NLRP3-mediated cell death-pyroptosis

Doxorubicin (Dox)-induced cardiac side effects are regulated through increased oxidative stress and apoptosis. However, it remains unknown whether Dox induces the specific inflammatory-mediated form of cell death called pyroptosis. The current study is undertaken to determine whether Dox induces pyroptosis in an in vitro model and to test the potential of exosomes derived from embryonic stem cells (ES-Exos) in inhibiting pyroptosis. H9c2 cells were exposed to Dox to generate pyroptosis and then subsequently treated with exosomes to investigate the protective effects of ES-Exos. Mouse embryonic fibroblast-exosomes (MEF-Exos) were used as a cell line control. We confirmed pyroptosis by analyzing the presence of Toll-like receptor 4 (TLR4)-pyrin domain containing-3 (NLRP3) inflammasome that initiates pyroptosis, which was further confirmed with pyroptotic markers caspase-1, IL-1β, caspase-11, and gasdermin-D. The presence of inflammation was confirmed for proinflammatory cytokines, TNF-α, and IL-6. Our data show that Dox exposure significantly (P < 0.05) increases expression of TLR4, NLRP3, pyroptotic markers (caspase-1, IL-1β, caspase-11, and gasdermin-D), and proinflammatory cytokines (TNF-α and IL-6) in H9c2 cells. The increased expression of inflammasome, pyroptosis, and inflammation was significantly (P < 0.05) inhibited by ES-Exos. Interestingly, our cell line control, MEF-Exos, did not show any protective effects. Furthermore, our cytokine array data suggest increased anti-inflammatory (IL-4, IL-9, and IL-13) and decreased proinflammatory cytokines (Fas ligand, IL-12, and TNF-α) in ES-Exos, suggesting that anti-inflammatory cytokines might be mediating the protective effects of ES-Exos. In conclusion, our data show that Dox induces pyroptotic cell death in the H9c2 cell culture model and is attenuated via treatment with ES-Exos.NEW & NOTEWORTHY Doxorubicin (Dox)-induced cardiotoxicity is mediated through increased oxidative stress, apoptosis, and necrosis. We report for the first time as per the best of our knowledge that Dox initiates Toll-like receptor 4 and pyrin domain containing-3 inflammasome formation and induces caspase-1-mediated inflammatory pyroptotic cell death in H9c2 cells. Moreover, we establish that inflammation and pyroptosis is inhibited by embryonic stem cell-derived exosomes that could be used as a future therapeutic option to treat Dox-induced cardiotoxicity.

Do Androgens Modulate the Pathophysiological Pathways of Inflammation? Appraising the Contemporary Evidence

The role of testosterone in the pathophysiology of inflammation is of critical clinical importance; however, no universal mechanism(s) has been advanced to explain the complex and interwoven pathways of androgens in the attenuation of the inflammatory processes. PubMed and EMBASE searches were performed, including the following key words: "testosterone", "androgens", "inflammatory cytokines", "inflammatory biomarkers" with focus on clinical studies as well as basic scientific studies in human and animal models. Significant benefits of testosterone therapy in ameliorating or attenuating the symptoms of several chronic inflammatory diseases were reported. Because anti⁻tumor necrosis factor therapy is the mainstay for the treatment of moderate-to-severe inflammatory bowel disease; including Crohn's disease and ulcerative colitis, and because testosterone therapy in hypogonadal men with chronic inflammatory conditions reduce tumor necrosis factor-alpha (TNF-α), IL-1β, and IL-6, we suggest that testosterone therapy attenuates the inflammatory process and reduces the burden of disease by mechanisms inhibiting inflammatory cytokine expression and function. Mechanistically, androgens regulate the expression and function of inflammatory cytokines, including TNF-α, IL-1β, IL-6, and CRP (C-reactive protein). Here, we suggest that testosterone regulates multiple and overlapping cellular and molecular pathways involving a host of immune cells and biochemical factors that converge to contribute to attenuation of the inflammatory process.

Inefficient N2-Like Neutrophils Are Promoted by Androgens During Infection

Neutrophils are major effectors of acute inflammation against infection and tissue damage, with ability to adapt their phenotype according to the microenvironment. Although sex hormones regulate adaptive immune cells, which explains sex differences in immunity and infection, little information is available about the effects of androgens on neutrophils. We therefore aimed to examine neutrophil recruitment and plasticity in androgen–dependent and –independent sites under androgen manipulation. By using a bacterial model of prostate inflammation, we showed that neutrophil recruitment was higher in testosterone-treated rats, with neutrophil accumulation being positively correlated to serum levels of testosterone and associated to stronger inflammatory signs and tissue damage. Testosterone also promoted LPS-induced neutrophil recruitment to the prostate, peritoneum, and liver sinusoids, as revealed by histopathology, flow cytometry, and intravital microscopy. Strikingly, neutrophils in presence of testosterone exhibited an impaired bactericidal ability and a reduced myeloperoxidase activity. This inefficient cellular profile was accompanied by high expression of the anti-inflammatory cytokines IL10 and TGFβ1, which is compatible with the “N2-like” neutrophil phenotype previously reported in the tumor microenvironment. These data reveal an intriguing role for testosterone promoting inefficient, anti-inflammatory neutrophils that prolong bacterial inflammation, generating a pathogenic environment for several conditions. However, these immunomodulatory properties might be beneficially exploited in autoimmune and other non-bacterial diseases.

Phage Therapy in Prostatitis: Recent Prospects

Prostatitis has various etiology including bacterial infection and dysregulated immunity; some of its forms remain a serious therapeutic challenge. Inflammation occurs in all forms of this disorder and is proposed to predispose to the development of prostate cancer (PC). There are reports that phage therapy is effective in chronic bacterial prostatitis. Recent findings suggest that phages not only eliminate bacteria, but also mediate immunomodulating (for example, anti-inflammatory) functions. The immunomodulating effects of phages could be beneficial in treating all forms of prostatitis and play some role in the prevention of the development of PC. As the etiological factors contributing to the majority of prostatitis cases remains largely unknown, and management options are often likewise limited, phage therapy merits further research as an attractive therapeutic option given its immunomodulating effects irrespective of the underlying causative factor(s).

Male accessory gland inflammation, infertility, and sexual dysfunctions: a practical approach to diagnosis and therapy

The role of urogenital inflammation in causing infertility and sexual dysfunctions has long been a matter of debate in the international scientific literature. The most recent scientific evidences show that male accessory gland infection/inflammation could alter, with various mechanisms, both conventional and biofunctional sperm parameters, and determine worst reproductive outcome. At the same time, the high prevalence of erectile dysfunction and premature ejaculation in patients with male accessory gland infection/inflammation underlines the close link between these diseases and sexual dysfunctions. The aim of this review was to provide the reader the basis for a correct diagnosis of male accessory gland infection/inflammation and a subsequent appropriate therapeutic approach, particularly in patients with infertility and/or sexual dysfunction.

Androgen regulation of host defenses and response to inflammatory stimuli in the prostate gland

The prostate gland is a strictly androgen-dependent organ which is also the main target of infectious and inflammatory diseases in the male reproductive tract. Host defenses and immunity of the gland have unique features to maintain a constant balance between response and tolerance to diverse antigens. In this context, the effects of reproductive hormones on the male tract are thus complex and have just started to be defined. From the classical description of "the prostatic antibacterial factor," many host defense proteins with potent microbicidal and anti-tumoral activities have been described in the organ. Indeed, it has been proposed a central role for resident cells, that is, epithelial and smooth muscle cells, in the prostatic response against injuries. However, these cells also represent the target of the inflammatory damage, leading to the development of a Proliferative Inflammatory Atrophy-like process in the epithelium and a myofibroblastic-like reactive stroma. Available data on androgen regulation of inflammation led to a model of the complex control, in which the final effect will depend on the tissue microenvironment, the cause of inflammation, and the levels of androgens among other factors. In this paper, we review the current scientific literature about the inflammatory process in the gland, the modulation of host defense proteins, and the influence of testosterone on the resolution of prostatitis.

Predictors and clinical consequences of starting androgen therapy in men with low testosterone: results from the SIAMO-NOI registry

PURPOSE

Management of late onset hypogonadism (LOH) is not homogenous. The aim of the study is to observe the management of patients with low testosterone (T) in highly specialized Italian centres.

METHODS

The SIAMO-NOI is an observational longitudinal disease registry for the evaluation of the clinical management of patients with low T levels (total T < 12 nmol/L, calculated free T < 225 pmol/l or already in treatment) in 15 Italian centers members of the Italian Society for Andrology and Sexual Medicine (SIAMS). Clinical and biochemical data were collected for four visits during 12 months of observation.

RESULTS

432 patients (mean age 50.9 ± 14.9 years) were enrolled. Of them, 247 men were receiving androgen therapy, whereas 145 were naive. After the first visit (V0), 80 men started androgen therapy, whereas 55 remained untreated during the entire observation. Younger age [odds ratio (OR) 0.57 (0.35-0.92)], total T < 8 nmol/l [OR 4.69 (1.59-13.81)], complaining at least one sexual symptom [OR 11.55 (2.01-66.35)] and reporting more severe lower urinary tract symptoms [OR 1.27 (1.01-1.60)] predicted starting an androgen therapy. Sixty-four men started therapy immediately after V0 and maintained it until the observation end. When compared to V0, they reported an increase in all the domains of the International Index of Erectile Function-15 (IIEF-15), in the sexual and physical subdomains of the Aging Male Scale as well as in the International Prostate Symptom Score. Conversely, the untreated group reported a significant improvement, although lower than the treated group, only in the erectile function domain of the IIEF-15.

CONCLUSIONS

Management of LOH in SIAMS centres is in line with the international guidelines and the newest knowledge about the role of T on prostate health. Androgen therapy is associated with an improvement in all the aspects of sexual life and in the perception of physical strength.

Nandrolone decanoate and resistance exercise training favor the occurrence of lesions and activate the inflammatory response in the ventral prostate

Age is a key factor in the development of prostatic lesions. An increase in reactive oxygen species levels occurs during aging. Furthermore, the indiscriminate use of anabolic androgenic steroids and physical exercise alter the availability of hormones and may promote the appearance of lesions. This study examined whether the use of nandrolone decanoate (ND), associated or not with resistance exercise training, affects the pathways related to the inflammatory response in the ventral prostate of adult and aged rats. Sprague-Dawley rats were distributed into eight experimental groups: sedentary with ND, sedentary without ND, exercise with ND, and exercise without ND. The animals performed resistance exercise training and received ND two times/week (5 mg/kg, i.m.) for 8 weeks. Adult rats were killed immediately following treatment completion, and aged rats remained untreated until reaching 300 days of age. The adult animals that received ND and performed resistance exercise training showed a higher occurrence of lesions with TLR4 activation. Marked IL-6 expression occurred in the group that performed resistance exercise training. The group exposed to ND showed overexpression of TLR2, TLR4, NOX1, Nrf2, TNF-α, and P38MAPK. The animals that received ND and performed training showed increase levels of NFκB, IRF3, IL-6, TNF-α, and NOX1. TLR2 and TLR4 showed no upregulation in the aged animals. The groups exercise + ND showed lesions in the adult stage and after aging, followed by molecular alterations. We concluded that nandrolone decanoate and resistance exercise training can promote the onset of prostatic tumors in the adult stage, and during aging, activating pathways involved in the inflammatory response.

The blood-epididymis barrier and inflammation

The blood-epididymis barrier (BEB) is a critical structure for male fertility. It enables the development of a specific luminal environment that allows spermatozoa to acquire both the ability to swim and fertilize an ovum. The presence of tight junctions and specific cellular transporters can regulate the composition of the epididymal lumen to favor proper sperm maturation. The BEB is also at the interface between the immune system and sperm. Not only does the BEB protect maturing spermatozoa from the immune system, it is also influenced by cytokines released during inflammation, which can result in the loss of barrier function. Such a loss is associated with an immune response, decreased sperm functions, and appears to be a contributing factor to post-testicular male infertility. Alterations in the BEB may be responsible for the formation of inflammatory conditions such as sperm granulomas. The present review summarizes current knowledge on the morphological, physiological and pathological components associated with the BEB, the role of immune function on the regulation of the BEB, and how disturbance of these factors can result in inflammatory lesions of the epididymis.

Toll-like receptors and prostate cancer

Prostate cancer is the second leading cause of cancer-related death in men after lung cancer. Immune responses clearly play a critical role in the tumorigenesis and in the efficacy of radiation therapy and chemotherapy in prostate cancer; however, the underlying molecular mechanisms are still poorly understood. Toll-like receptors (TLRs) are a well-known family of pattern recognition receptors that play a key role in host immune system. Recent studies demonstrate that there are links between TLRs and cancer; however, the function and biological importance of TLRs in prostate cancer seems complex. To elucidate the role of TLRs and innate immunity in prostate cancer might provide us with a better understanding of the molecular mechanisms of this disease. Moreover, utilizing the agonists or antagonists of TLRs might represent a promising new strategy against prostate cancer. In this review, we summarize recent advances on the studies of association between TLR signaling and prostate cancer, TLR polymorphisms and prostate cancer risk, and provide some insights about TLRs as potential targets for prostate cancer immunotherapy.

Male accessory gland infection: relevance of serum total testosterone levels

Aim of the present study was to evaluate the different ultrasound characterization of fertile symptomatic patients with MAGI (male accessory gland infection) according to different serum concentrations of total T (TT). We analyzed the ultrasound and hormonal data of 200 patients aged between 24.0 and 67.0 years. Patients were divided into six groups according to the sextile distribution of TT. Patients with serum concentrations of TT < 3.6 ng mL(-1) had a higher mean duration of symptoms compared to the other examined groups. Patients with serum concentrations of TT > 6.6 ng mL(-1) showed a frequency of ultrasound criteria suggestive for bilateral form of prostatitis and prostate-vesiculo-epididymitis and significantly lower compared to the other examined groups. At multivariate logistic regression analysis adjusted for age and BMI, TT was an independent predictive factor of prostatovesiculitis (OR = 0.818 [95% CI: 0.675-0.992]; P < 0.01) and prostate-vesiculo-epididymitis (OR = 0.714 [95% CI: 0.578-0.880]; P < 0.01), which represent the main forms of complicated MAGI. The results of this study suggest that male hypogonadism could be associated with a different ultrasound characterization of these patients.

Microbiological investigation in male infertility: a practical overview

The roles of inflammation and/or infection of the male accessory sex glands are very important for the potential effects that these conditions may have on male fertility. The clinical andrologist should be aware of the pathophysiological role of the main determinants of sperm damage when these conditions occur, in particular, seminal leukocytes, oxidative stress and cytokines. In addition, it is important to have a good knowledge of the methodologies to be used in clinical practice. This article summarizes the methods used to look for and to identify the micro-organisms responsible for male urogenital tract infections. These include sperm culture, urine culture, urethral swabbing, the Meares–Stamey test and balanopreputial swabbing. Finally, we discuss the role of human papilloma virus infection in male infertility.

Tamsulosin alters levofloxacin pharmacokinetics in prostates derived from rats with acute bacterial prostatitis

The combination of levofloxacin and α1 adrenergic antagonist treatment is the current preferred choice for both bacterial and non-bacterial prostatitis. The aim of this study is to explore the influence of α1 adrenergic antagonists on the pharmacokinetics of levofloxacin using rat models with acute bacterial prostatitis (ABP) induced by direct injection with Escherichia coli (ATCC25922). A total of 96 model rats were randomly assigned into two groups: the experimental group (treated with both tamsulosin and levofloxacin, n=48) and the control group (treated with levofloxacin and solvents, n=48). Six rats from each group were euthanized to collect blood, liver, kidney and prostate samples at the time points of 0.125, 0.25, 0.5, 1, 2, 4, 8 and 12 h after drug administration. The levofloxacin concentrations were detected by high performance liquid chromatography (HPLC), and the pharmacokinetic parameters were calculated using the 3p97 software program. There were no obvious differences (P>0.05) between the experimental and control groups in the major pharmacokinetic parameters of levofloxacin, including the halftime (t1/2), time to peak (tpeak), clearance rate (CL), maximum concentration (Cmax) and area under the curve (AUC0∼12), in the plasma or in the hepatic and kidney tissues of the model rats. However, in the prostatic tissues, tamsulosin increased the Cmax, prolonged the t1/2 and decreased the CL of levofloxacin (P<0.05). These results indicate that tamsulosin may enhance the effect of levofloxacin in the treatment of bacterial prostatitis without changing the drug concentration in the liver and kidney.

Antiinflammatory effect of androgen receptor activation in human benign prostatic hyperplasia cells

Progression of benign prostatic hyperplasia (BPH) involves chronic inflammation and immune dysregulation. Preclinical studies have demonstrated that prostate inflammation and tissue remodeling are exacerbated by hypogonadism and prevented by testosterone supplementation. We now investigated whether, in humans, hypogonadism was associated with more severe BPH inflammation and the in vitro effect of the selective androgen receptor agonist dihydrotestosterone (DHT) on cultures of stromal cells derived from BPH patients (hBPH). Histological analysis of inflammatory infiltrates in prostatectomy specimens from a cohort of BPH patients and correlation with serum testosterone level was performed. Even after adjusting for confounding factors, hypogonadism was associated with a fivefold increased risk of intraprostatic inflammation, which was also more severe than that observed in eugonadal BPH patients. Triggering hBPH cells by inflammatory stimuli (tumor necrosis factor α, lipopolysaccharide, or CD4(+)T cells) induced abundant secretion of inflammatory/growth factors (interleukin 6 (IL6), IL8, and basic fibroblast growth factor (bFGF)). Co-culture of CD4(+)T cells with hBPH cells induced secretion of Th1 inducer (IL12), Th1-recruiting chemokine (interferon γ inducible protein 10, IP10), and Th2 (IL9)- and Th17 (IL17)-specific cytokines. Pretreatment with DHT inhibited NF-κB activation and suppressed secretion of several inflammatory/growth factors, with the most pronounced effects on IL8, IL6, and bFGF. Reduced inflammatory cytokine production by T-cells, an increase in IL10, and a significant reduction of T cells proliferation suggested that DHT exerted a broad anti inflammatory effect on testosterone cells [corrected]. In conclusion, our data demonstrate that DHT exerts an immune regulatory role on human prostatic stromal cells, inhibiting their potential to actively induce and/or sustain autoimmune and inflammatory responses.

Immunomodulatory effects of testosterone evaluated in all-trans retinoic acid differentiated HL-60 cells, granulocytes, and monocytes

The sex hormones are known to affect innate immunity in humans. In this study we evaluated the immunomodulatory effects of testosterone in a model system comprising of all-trans retinoic acid differentiated HL-60 cells, and confirmed the results in human granulocytes and monocytes. Results showed that testosterone at pharmacological doses reduced the production of interleukin-8 and reactive oxygen species from differentiated HL-60 cells in a concentration dependent manner without affecting phagocytosis. The cells were stimulated with zymosan, lipopolysaccharide, or Bacillus subtilis. At the highest concentration of testosterone (120 μM), interleukin-8 secretion was reduced 42-80%, and production of reactive oxygen species was reduced 32-46%. Flutamide, an antagonist of the classical intracellular androgen receptor, was unable to antagonize the immunosuppressive effect of testosterone. We further demonstrated that the suppressive effect of testosterone has a short onset time. Our results suggest that testosterone affects the fast operating membrane bound androgen receptor or a rapid acting enzyme system. Testosterone, at pharmacological doses, was also shown to suppress generation of reactive oxygen species and interleukin-8 in human granulocytes and monocytes, respectively, to a similar extent as observed in differentiated HL-60 cells.

Testosterone protects from metabolic syndrome-associated prostate inflammation: an experimental study in rabbit

Metabolic syndrome (MetS) and benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) are often associated. One of their common denominators is hypogonadism. However, testosterone supplementation is limited by concerns for potential prostatic side effects. The objective was to determine whether MetS-associated prostate alterations are prevented by testosterone supplementation. We used a previously described animal model of MetS, obtained by feeding male rabbits a high-fat diet (HFD) for 12 weeks. Subsets of HFD rabbits were treated with testosterone or with the farnesoid X receptor agonist INT-747. Rabbits fed a standard diet were used as controls. HFD-animals develop hypogonadism and all the MetS features: hyperglycemia, glucose intolerance, dyslipidemia, hypertension, and visceral obesity. In addition, HFD-animals show a prostate inflammation. Immunohistochemical analysis demonstrated that HFD-induced prostate fibrosis, hypoxia, and inflammation. The mRNA expression of several proinflammatory (IL8, IL6, IL1β, and TNFα), T lymphocyte (CD4, CD8, Tbet, Gata3, and ROR γt), macrophage (TLR2, TLR4, and STAMP2), neutrophil (lactoferrin), inflammation (COX2 and RAGE), and fibrosis/myofibroblast activation (TGFβ, SM22α, αSMA, RhoA, and ROCK1/ROCK2) markers was significantly increased in HFD prostate. Testosterone, as well as INT-747, treatment prevented some MetS features, although only testosterone normalized all the HFD-induced prostate alterations. Interestingly, the ratio between testosterone and estradiol plasma level retains a significant, negative, association with all the fibrosis and the majority of inflammatory markers analyzed. These data highlight that testosterone protects rabbit prostate from MetS-induced prostatic hypoxia, fibrosis, and inflammation, which can play a role toward the development/progression of BPH/LUTS.

Dedifferentiation of prostate smooth muscle cells in response to bacterial LPS

BACKGROUND

Prostate smooth muscle cells (SMCs) are strongly involved in the development and progression of benign prostatic hyperplasia and prostate cancer. However, their participation in prostatitis has not been completely elucidated. Thus, we aimed to characterize the response of normal SMC to bacterial lipopolysaccharide (LPS).

METHODS

Primary prostate SMCs from normal rats were stimulated with LPS (0.1, 1, or 10 µg/ml) for 24 or 48 hr. The phenotype was evaluated by electron microscopy, immunofluorescence, and Western blot of SMCα-actin (ACTA2), calponin, vimentin, and tenascin-C, while the innate immune response was assessed by immunodetection of TLR4, CD14, and nuclear NF-κB. The secretion of TNFα and IL6 was determined using ELISA.

RESULTS

Bacterial LPS induces SMCs to develop a secretory phenotype including dilated rough endoplasmic reticulum cisternae with well-developed Golgi complexes. Furthermore, SMCs displayed a decrease in ACTA2 and calponin, and an increase in vimentin levels after LPS challenge. The co-expression of ACTA2 and vimentin, together with the induction of tenascin-C expression indicate that a myofibroblastic-like phenotype was induced by the endotoxin. Moreover, LPS elicited a TLR4 increase, with a peak in NF-κB activation occurring after 10 min of treatment. Finally, LPS stimulated the secretion of IL6 and TNFα.

CONCLUSIONS

Prostate SMCs are capable of responding to LPS in vitro by dedifferentiating from a contractile to a miofibroblastic-like phenotype and secreting cytokines, with the TLR4 signaling pathway being involved in this response. In this way, prostate SMCs may contribute to the pathophysiology of inflammatory diseases by modifying the epithelial-stromal interactions.

Acute inflammation promotes early cellular stimulation of the epithelial and stromal compartments of the rat prostate

BACKGROUND

It has been proposed that prostatic inflammation plays a pivotal role in the pathophysiology of benign hyperplasia and prostate cancer. However, little information is available about the prostatic reaction to bacterial compounds in vivo. Our aim was therefore to evaluate the early effects of bacterial infection on rat ventral prostate compartments.

METHODS

Using a rat model of acute bacterial prostatitis by Escherichia coli, we analyzed the histological and ultrastructural changes in the prostate at 24, 48, and 72 hr postinfection. Prostatic tissues were immunostained for prostatic binding protein (PBP), ACTA2, ErbB1, and ErbB2 receptors, TUNEL, and markers of cell proliferation. Dot and Western blots for PBP, ACTA2, ErbB1, ErbB2, and TGFbeta1 were also performed.

RESULTS

The prostatic epithelium became hypertrophied, with increases in PBP and ErbB1 expression at 24 hr postinfection. Moreover, inflammation induced the expression of ErbB2, a receptor strongly involved in carcinogenesis. These alterations were more pronounced at 48 hr, but the epithelium also showed apoptosis and finally atrophy at 72 hr postinfection, with a decrease in PBP and ErbB receptors. Interestingly, the epithelial cells exhibited a high level of proliferation in response to the bacteria. The stromal reaction to acute inflammation was initially characterized by smooth muscle hypertrophy. Afterwards, muscle cells acquired a secretory phenotype, with a reduction in ACTA2 at 72 hr postinfection.

CONCLUSIONS

Prostatic inflammation, even at the early stages, promotes atrophic and proliferative changes, and the upregulation of ErbB receptors together with dedifferentiation of smooth muscle cells. These data suggest that repetitive reinfections could lead to uncontrolled growth in the prostate gland.

Immunology of the Testis and Male Reproductive Tract

A large body of evidence points to the existence of a close, dynamic relationship between the immune system and the male reproductive tract, which has important implications for our understanding of both systems. The testis and the male reproductive tract provide an environment that protects the otherwise highly immunogenic spermatogenic cells and sperm from immunological attack. At the same time, secretions of the testis, including androgens, influence the development and mature functions of the immune system. Activation of the immune system has negative effects on both androgen and sperm production, so that systemic or local infection and inflammation compromise male fertility. The mechanisms underlying these interactions have begun to receive the attention from reproductive biologists and immunologists that they deserve, but many crucial details remain to be uncovered. A complete picture of male reproductive tract function and its response to toxic agents is contingent upon continued exploration of these interactions and the mechanisms involved.

Expression of Toll-like receptor 4 in the prostate gland and its association with the severity of prostate cancer

BACKGROUND

Chronic inflammation has been postulated to be an important driving force to prostate carcinoma. Toll-like receptors (TLRs) compose a family of receptors mainly expressed on immune cells. Recently, functional TLRs have been shown to be also expressed in numerous cancer cells, but their significance has only recently begun to be explored. The purpose of this study was to investigate the putative role of TLR4 expression in prostate carcinoma.

METHODS

To determine if there is an association between TLR4 expression and the malignancy of the tumor, 35 prostate carcinoma samples showing different Gleason grades were analyzed by immunohistochemistry. Also, to explore the functionality of the receptors expressed on the epithelium, we analyzed the type of cytokine response elicited and the signaling pathways involved after TLR4 triggering in the human prostate adenocarcinoma cell line, DU-145.

RESULTS

TLR4 is expressed in the normal prostate gland in both stroma and epithelium. TLR4 expression significantly drops to negative values as the Gleason grade augments in both, stroma and epithelium. Moreover, DU-145 cells also exhibit TLR4 expression and respond to TLR4 agonists, activating the transcription factor NF-kappaB and increasing the expression of pro-inflammatory mediators. Inhibition of the molecular adaptors MyD88 and MAL by overexpression of dominant-negative mutants diminished LPS-induced activation of NF-kappaB, showing that DU-145 cells activate the NF-kappaB through MyD88-dependent signaling pathways.

CONCLUSIONS

We hypothesize that TLR4 in prostate cells could synergize with innate immune cells contributing to an eventual inflammatory process, which in genetically prone individuals could promote carcinogenesis. Prostate 69: 1387-1397, 2009. (c) 2009 Wiley-Liss, Inc.

Activation of toll-like receptor 4 (TLR4) by in vivo and in vitro exposure of rat epididymis to lipopolysaccharide from Escherichia Coli

This study provides the first evidence that rat epididymis is fully capable of initiating an inflammatory response to lipopolysaccharide (LPS) from Escherichia coli through activation of Toll-like receptor 4 (TLR4). TLR4 functionality was demonstrated by in vivo LPS challenge, which induced a time- and dose-dependent activation of the transcription factor nuclear factor kappa B (NFKB) in caput and cauda epididymides. NFKB activation by LPS in caput epididymidis was abrogated when rats were pretreated with the NFKB inhibitor PDTC, confirming the specificity of this response. Within 2 h of LPS treatment (0.01 and 1 mg/kg, i.v.), NFKB activation in caput and cauda was accompanied by upregulation of Il1b, Nfkbia, and Cd14, but not Tlr4, mRNA. These effects, however, were not sustained after 24 h of LPS treatment. Lipopolysaccharide systemic effects were not restricted to epididymides, since Il1b, Nfkbia, and Cd14 mRNAs were also upregulated in other male reproductive tissues from LPS-treated rats (1 mg/kg, i.v., 2 h). Constitutive TLR4 was immunolocalized in some, but not all, epididymal epithelial cells and in interstitial cells, some of them identified as resident ED2-positive macrophages. No change in TLR4 immunostaining pattern was observed when epididymides from control and LPS-treated rats were compared (1 mg/kg, i.v., 2 h and 24 h). Significant NFKB activation was also achieved within 1 min of in vitro incubation of caput epididymidis with LPS (0.01-5 mug/ml), confirming that components for TLR4 signaling cascade activation are fully active in this tissue. This study contributes to a better understanding of the innate immune response in the epididymis and other tissues from the male reproductive tract.

Testosterone reduces macrophage expression in the mouse of toll-like receptor 4, a trigger for inflammation and innate immunity

Though gender-based differences in the development of protective or pathological adaptive host responses have been widely noted, it is becoming apparent that sex may also influence the early perception of microbial challenges and the generation of inflammatory immune responses. These differences may be due to the actions of reproductive hormones, and such a hypothesis is supported by the presence of receptors for these hormones in a variety of immune cell types. Androgens such as testosterone have been shown to decrease immune functions, including cytokine production. However, the mechanisms by which testosterone limits such responses remain undefined. In this study, we have investigated the acute effects of testosterone on the level of expression of a key trigger for inflammation and innate immunity, Toll-like receptor 4 (TLR4), on isolated mouse macrophages. We show that in vitro testosterone treatment of macrophages, generated in the absence of androgen, elicits a modest but significant decrease in TLR4 expression and sensitivity to a TLR4-specific ligand. In addition, we have studied the effect of in vivo removal of endogenous testosterone on TLR4 expression and endotoxin susceptibility. We report that orchidectomized mice were significantly more susceptible to endotoxic shock and show that macrophages isolated from these animals have significantly higher TLR4 cell surface expression than those derived from sham gonadectomized mice. Importantly, these effects were not apparent in orchidectomized animals that received exogenous testosterone treatment. As such, these data may represent an important mechanism underlying the immunosuppressive effects of testosterone.

Regulation of surfactant protein D in the rodent prostate

BACKGROUND

Surfactant protein D (SP-D) is an innate immune protein that is present in mucosal lined surfaces throughout the human body, including the male reproductive tract. In the present study, we characterized the regulation of SP-D expression in the mouse and rat prostate.

METHODS

Real time reverse transcriptase polymerase chain reaction (RT-PCR) and immunostaining were used to characterize SP-D mRNA and protein in the mouse male reproductive tract. In order to evaluate the effects of testosterone on SP-D gene expression, we measured SP-D mRNA levels via real time RT-PCR in prostates from sham-castrated mice and castrated mice. In addition, we used a rat prostatitis model in which Escherichia coli was injected into the prostate in vivo to determine if infection influences SP-D protein levels in the prostate.

RESULTS

We found that SP-D mRNA and protein are present throughout the mouse male reproductive tract, including in the prostate. We determined that castration increases prostate SP-D mRNA levels (~7 fold) when compared to levels in sham-castrated animals. Finally, we demonstrated that infection in the prostate results in a significant increase in SP-D content 24 and 48 hours post-infection.

CONCLUSION

Our results suggest that infection and androgens regulate SP-D in the prostate.

Effect of bacterial endotoxin LPS on expression of INF-gamma and IL-5 in T-lymphocytes from asthmatics

Epidemiological evidence, in vitro studies and animal models suggest that exposure to the bacterial endotoxin lipopolysaccharide (LPS) can influence the development and severity of asthma. Although it is known that signaling through Toll-like receptors (TLR) is required for adaptive T helper cell type 1 and 2 responses, it is unclear whether the LPS ligand TLR 4 is expressed on CD4(+) and CD8(+) T-lymphocytes and if so, whether LPS could modulate the T(H)1 or T(H)2 response in this context. The present authors have, therefore, examined the expression of TLR 4 on peripheral blood CD4(+) and CD8(+) T-lymphocytes using RT-PCR method and FACS analyses. Furthermore, the authors have studied the IL-12-induced expression of the T(H)1-associated cytokine INF-gamma and the IL-4-induced expression of the T(H)2-specific cytokine IL-5 in the presence of LPS using ELISA and compared nine atopic asthmatic subjects and eleven nonatopic normal volunteers. There was an increased anti-CD3/anti-CD28-induced IL-5 expression in T cells of asthmatics compared with normals (p<0.01). In the presence of IL-4 (10 ng/ml), there was an additional increase in IL-5 expression and this additional increase was greater in T cells of normals compared with asthmatics (p<0.05). There was an expression of INF-gamma in anti-CD3/anti-CD28-induced T-lymphocytes without differences between both groups (NS). In the presence of IL-12 (10 ng/ml), there was an increase in INF-gamma release without differences between normals and asthmatics (NS). In the presence of different concentrations of LPS (10 ng/ml, 1 mug/ml), there was a decrease in IL-4-induced IL-5 expression without differences in both groups, indicating an intact T(H)2 response to bacterial endotoxin LPS in asthma. Interestingly, LPS increased the IL-12-induced INF-gamma release in a concentration-dependent manner in T-lymphocytes of normals but this could not be found in T cells of asthmatics, indicating an impaired T(H)1 response to bacterial endotoxin LPS in asthma. In addition, there was a TLR 4 expression on CD4(+) T-lymphocytes of normals and to a lesser extent in asthmatics but this TLR 4 expression could not be found on CD8(+) T cells of both groups. In conclusion, there may be an impaired concentration-dependent LPS-induced T(H)1 rather than a T(H)2 response in allergic adult asthmatics compared with normal volunteers. One reason for this could be a reduced TLR 4 expression on CD4(+) T-lymphocytes of asthmatic subjects.

Toll‐like receptors in the gonads and reproductive tract: emerging roles in reproductive physiology and pathology

Interactions between the immune system and reproductive system have important consequences for fertility and reproductive health in general. There is increasing evidence that many of the interactions between the immune and reproductive systems involve the Toll-like receptors (TLRs). While there is no doubt that TLRs are important in providing protection against infection in the reproductive tract, there is increasing evidence for the involvement of TLRs in more basic pathology and physiology of reproduction. In the female, TLRs have been implicated in critical aspects of ovarian, endometrial and placental function, as well as in ovarian cancer, pelvic inflammatory disease, intrauterine growth restriction, pre-eclampsia and preterm birth. In the male, TLRs appear to play a role in the control of testicular steroidogenesis and spermatogenesis in disease and, potentially, during normal function, as well. Recent studies also have begun to highlight the role of various TLRs in the aetiology of prostatitis and prostatic cancer. Given the nascent state of knowledge concerning this important area, it is clear that more studies are needed, which should provide valuable new insights into the biology of the TLRs and reproductive function in general.