The Immune-Pineal Axis: the Role of Pineal and Extra-Pineal Melatonin in Modulating Inflammation

Looking beyond Self-Protection: The Eyes Instruct Systemic Immune Tolerance Early in Life

The eyes provide themselves with immune tolerance. Frequent skin inflammatory diseases in young blind people suggest, nonetheless, that the eyes instruct a systemic immune tolerance that benefits the whole body. We tested this premise by using delayed skin contact hypersensitivity (DSCH) as a tool to compare the inflammatory response developed by sighted (S) and birth-enucleated (BE) mice against oxazolone or dinitrofluorobenzene at the ages of 10, 30 and 60 days of life. Adult mice enucleated (AE) at 60 days of age were also assessed when they reached 120 days of life. BE mice displayed exacerbated DSCH at 60 but not at 10 or 30 days of age. AE mice, in contrast, show no exacerbated DSCH. Skin inflammation in 60-day-old BE mice was hapten exclusive and supported by distinct CD8+ lymphocytes. The number of intraepidermal T lymphocytes and migrating Langerhans cells was, however, similar between S and BE mice by the age of 60 days. Our observations support the idea that the eyes instruct systemic immune tolerance that benefits organs outside the eyes from an early age. The higher prevalence of inflammatory skin disorders reported in young people might then reflect reduced immune tolerance associated with the impaired functional morphology of the eyes.

Physiological and pharmacological perspectives of melatonin

The pineal gland is a interface between light-dark cycle and shows neuro-endocrine functions. Melatonin is the primary hormone of pineal gland, secreted at night. The night-time melatonin peak regulates the physiological functions at dark. Melatonin has several unique features as it synchronises internal rhythm with daily and seasonal variations, regulates circadian rhythm and sleep-wake cycle. Physiologically melatonin involves in detoxification of free radicals, immune functions, neuro-protection, oncostatic effects, cardiovascular functions, reproduction, and foetal development. The precise functions of melatonin are exhibited by specific receptors. In relation to pathophysiology, impaired melatonin secretion promotes sleep disorder, cancer progression, type-2 diabetes, and neurodegenerative diseases. Several reports have highlighted the therapeutic benefits of melatonin specially related to cancer protection, sleep disorder, psychiatric disorders, and jet lag problems. This review will touch the most of the area of melatonin-oriented health impacts and its therapeutic aspects.

Effects of the social environment on vertebrate fitness and health in nature: Moving beyond the stress axis

Social interactions are a ubiquitous feature of the lives of vertebrate species. These may be cooperative or competitive, and shape the dynamics of social systems, with profound effects on individual behavior, physiology, fitness, and health. On one hand, a wealth of studies on humans, laboratory animal models, and captive species have focused on understanding the relationships between social interactions and individual health within the context of disease and pathology. On the other, ecological studies are attempting an understanding of how social interactions shape individual phenotypes in the wild, and the consequences this entails in terms of adaptation. Whereas numerous studies in wild vertebrates have focused on the relationships between social environments and the stress axis, much remains to be done in understanding how socially-related activation of the stress axis coordinates other key physiological functions related to health. Here, we review the state of our current knowledge on the effects that social interactions may have on other markers of vertebrate fitness and health. Building upon complementary findings from the biomedical and ecological fields, we identify 6 key physiological functions (cellular metabolism, oxidative stress, cellular senescence, immunity, brain function, and the regulation of biological rhythms) which are intimately related to the stress axis, and likely directly affected by social interactions. Our goal is a holistic understanding of how social environments affect vertebrate fitness and health in the wild. Whereas both social interactions and social environments are recognized as important sources of phenotypic variation, their consequences on vertebrate fitness, and the adaptive nature of social-stress-induced phenotypes, remain unclear. Social flexibility, or the ability of an animal to change its social behavior with resulting changes in social systems in response to fluctuating environments, has emerged as a critical underlying factor that may buffer the beneficial and detrimental effects of social environments on vertebrate fitness and health.

CasEcR and CasMIH Genes in the Blue Crab, Callinectes sapidus: A Temporal Evaluation and Melatonin Effects

Environmental cues synchronize endogenous rhythms of many physiological processes such as hormone synthesis and secretion. Little is known about the diurnal pattern of hormones and gene expression of the Callinectes sapidus molt cycle. We aimed to investigate in the eyestalk and hepatopancreas of premolt and intermolt C. sapidus the following parameters: 1) the diurnal expression of the ecdysteroid receptor CasEcR isoforms, and the molt inhibiting hormone CasMIH; 2) the diurnal hemolymph ecdysteroid and melatonin levels; and 3) melatonin effects on the transcripts of the above-mentioned genes in intermolt C. sapidus. Ecdysteroid levels were higher in the premolt than the intermolt animals at all time points evaluated (ZTs). Premolt crabs displayed a variation of ecdysteroid concentration between time points, with a reduction at ZT17. No difference in the melatonin level was seen in either molt stage or between stages. In the eyestalk of intermolt animals, CasEcR expression oscillated, with a peak at ZT9, and premolt crabs have a reduction at ZT9; CasMIH transcripts did not vary along 24 h in either molt stage. Moreover, the evaluated eyestalk genes were more expressed at ZT9 in the intermolt than the premolt crabs. In the hepatopancreas, CasEcR expression showed a peak at ZT9 in premolt crabs. Exogenous melatonin (10⁻⁷ mol/animal) reduced the expression of both genes in the eyestalk at ZT17. In the hepatopancreas, melatonin markedly increased the expression of the CasEcR gene at ZT9. Taken altogether, our results are pioneer in demonstrating the daily oscillation of gene expression associated to molt cycle stages, as well as the daily ecdysteroid and melatonin levels and the remarkable influence of melatonin on the molt cycle of C. sapidus.

Melatonin as the Cornerstone of Neuroimmunoendocrinology

Much attention has been recently drawn to studying melatonin – a hormone whose synthesis was first found in the epiphysis (pineal gland). This interest can be due to discovering the role of melatonin in numerous physiological processes. It was the discovery of melatonin synthesis in endocrine organs (pineal gland), neural structures (Purkinje cells in the cerebellum, retinal photoreceptors), and immunocompetent cells (T lymphocytes, NK cells, mast cells) that triggered the evolution of new approaches to the unifield signal regulation of homeostasis, which, at the turn of the 21st century, lead to the creation of a new integral biomedical discipline — neuroimmunoendocrinology. While numerous hormones have been verified over the last decade outside the “classical” locations of their formation, melatonin occupies an exclusive position with regard to the diversity of locations where it is synthesized and secreted. This review provides an overview and discussion of the major data regarding the role of melatonin in various physiological and pathological processes, which affords grounds for considering melatonin as the “cornerstone” on which neuroimmunoendocrinology has been built as an integral concept of homeostasis regulation.

Exposure to artificial light at night alters innate immune response in wild great tit nestlings

The large-scale impact of urbanization on wildlife is rather well documented; however, the mechanisms underlying the effects of urban environments on animal physiology and behaviour are still poorly understood. Here, we focused on one major urban pollutant - artificial light at night (ALAN) - and its effects on the capacity to mount an innate immune response in wild great tit (Parus major) nestlings. Exposure to ALAN alters circadian rhythms of physiological processes, by disrupting the nocturnal production of the hormone melatonin. Nestlings were exposed to a light source emitting 3 lx for seven consecutive nights. Subsequently, nestlings were immune challenged with a lipopolysaccharide injection, and we measured haptoglobin and nitric oxide levels pre- and post-injection. Both haptoglobin and nitric oxide are important markers for innate immune function. We found that ALAN exposure altered the innate immune response, with nestlings exposed to ALAN having lower haptoglobin and higher nitric oxide levels after the immune challenge compared with dark-night nestlings. Unexpectedly, nitric oxide levels were overall lower after the immune challenge than before. These effects were probably mediated by melatonin, as ALAN-treated birds had on average 49% lower melatonin levels than the dark-night birds. ALAN exposure did not have any clear effects on nestling growth. This study provides a potential physiological mechanism underlying the documented differences in immune function between urban and rural birds observed in other studies. Moreover, it gives evidence that ALAN exposure affects nestling physiology, potentially causing long-term effects on physiology and behaviour, which ultimately can affect their fitness.

Beneficial Effects of Exogenous Melatonin in Acute Staphylococcus aureus and Escherichia coli Infection-Induced Inflammation and Associated Behavioral Response in Mice After Exposure to Short Photoperiod

The administration of melatonin during acute bacterial infection was evaluated in this study. Mice pre-exposed to normal photoperiodic (NP), short photoperiodic (SP), and long photoperiodic (LP) day lengths were infected separately with live Staphylococcus aureus (5 × 10⁶ cells/ml) or Escherichia coli (2.5 × 10⁷ colony-forming units/ml) and treated with melatonin (10 mg/kg body weight). Behavioral studies were performed before bacterial infection and after melatonin administration. In mice pre-exposed to SP, exogenous melatonin administration resulted in better clearance of bacteria from blood and behavioral improvement. Reduced glutathione content and superoxide dismutase activities were increased, with concomitant decrease in lipid peroxidation content and catalase activities in the liver, brain, and spleen after exogenous melatonin administration. The overproduction of tumor necrosis factor-α, interferon-γ, and interleukin-6 during acute bacterial infection in mice exposed to different photoperiods was probably regulated by the administration of exogenous melatonin, by reducing neutrophil recruitment to spleen, expression of inducible nitric oxide synthase and cyclooxygenase-2 in hypothalamus, and C-reactive protein in the serum, and was also associated with improved behavioral response. Photoperiodic variations in inflammatory and oxidative stress markers might be correlated to serum melatonin and corticosterone levels. This study suggests that the administration of melatonin during SP exposure is protective in infection-induced inflammation than NP and LP exposure.

Dual Effect of Catecholamines and Corticosterone Crosstalk on Pineal Gland Melatonin Synthesis

BACKGROUND/AIM

The nocturnal production of melatonin by the pineal gland is triggered by sympathetic activation of adrenoceptors and may be modulated by immunological signals. The effect of glucocorticoids on nocturnal melatonin synthesis is controversial; both stimulatory and inhibitory effects have been reported. During pathophysiological processes, an increased sympathetic tonus could result in different patterns of adrenoceptor activation in the pineal gland. Therefore, in this investigation, we evaluated whether the pattern of adrenergic stimulation of the pineal gland drives the direction of the glucocorticoid effect on melatonin production.

METHODS

The corticosterone effect on the pineal hormonal production induced by β-adrenoceptor or β+α1-adrenoceptor activation was evaluated in cultured glands. We also investigated whether the in vivo lipopolysaccharide (LPS)-induced inhibition of melatonin is dependent on the interaction of glucocorticoids and the α1-adrenoceptor in adrenalectomized animals and on the in vivo blockade of glucocorticoid receptors (GRs) or the α1-adrenoceptor.

RESULTS

Corticosterone potentiated β-adrenoceptor-induced pineal melatonin synthesis, whilst corticosterone-dependent inhibition was observed when melatonin production was induced by β+α1-adrenoceptors agonists. The inhibitory effect of corticosterone is mediated by GR, as it was abolished in the presence of a GR antagonist. Moreover, LPS-induced reduction in melatonin nocturnal plasma content was reversed by adrenalectomy and by antagonizing GR or α1-adrenoceptors.

CONCLUSIONS

The dual effect of corticosterone on pineal melatonin synthesis is determined by the activation pattern of adrenoceptors (β or β+α1) in the gland during GR activation, suggesting that increased activation of the sympathetic system and the hypothalamic-pituitary-adrenal axis are necessary for the control of melatonin production during defense responses.

ACTH modulation on corticosterone, melatonin, testosterone and innate immune response in the tree frog Hypsiboas faber

The modulation exerted by glucocorticoids in physiological responses to stressors is essential for maintaining short-term homeostasis. However, highly frequent and/or prolonged activation of the hypothalamic-pituitary-adrenal/interrenal axis may inhibit processes that are important to long-term fitness and health, including reproduction and immunocompetence. The present study evaluates the response to adrenocorticotropic hormone (ACTH) injection in the adult male tree frog, Hypsiboas faber, as indicated by levels of plasma corticosterone (CORT), plasma testosterone (T), ocular melatonin (MEL), hematocrit and immune functioning (total leukocyte count and bacterial killing ability against Escherichia coli). All levels were measured 1, 3 and 6h after treatment. ACTH increased CORT levels whilst decreasing T and MEL levels at 1h post-treatment. 6h after ACTH injection, hematocrit and MEL levels increased. ACTH treatment did not significantly modulate the immune measures over the time-range sampled. The hormonal changes observed in response to ACTH treatment suggest that stressors could act as inhibitors of reproductive activity, as well as differentially modulating melatonin levels at different time-points.

The RelA/cRel nuclear factor-κB (NF-κB) dimer, crucial for inflammation resolution, mediates the transcription of the key enzyme in melatonin synthesis in RAW 264.7 macrophages

Lipopolysaccharide (LPS) modulates the transcription of the gene that codifies the enzyme arylalkylamine-N-acetyltransferase (AA-NAT) through nuclear translocation of the transcription factor nuclear factor-κ-light-chain-enhancer of activated B cells (NF-κB). AA-NAT converts serotonin to N-acetylserotonin, the ultimate precursor of melatonin. Activation of kappa B elements (aa-nat-κB), localized in the promoter (nat-κB1 and nat-κB2), leads to Aa-nat transcription in RAW 264.7 macrophages. Competitive electrophoretic mobility shift assay (EMSA) with oligonucleotide probes corresponding to each of the two elements, as well as a NF-κB consensus corresponding probe, revealed different specificities for each κB element. In addition, activator protein-1 (AP-1) as well as signal transducers and activator of transcription-1 and 3 (STAT-1; STAT-3) competed with NF-κB for binding to nat-κB1, while only STAT-3 competed with NF-κB for binding to nat-κB2. According to co-immunoprecipitation (ChiP) assays, these two sites are able to distinguish NF-κB subunits. The sequence nat-κB1 bound dimers containing p52, RelA, and cRel, while nat-κB2 bound preferentially p50, p52, and RelA, and did not bind cRel. The expression of RelA and cRel is essential for the induction of Aa-nat expression and melatonin synthesis. Considering that the expression of cRel is induced by the earlier expressed p50/RelA, the differential effects of NF-κB dimers may be intimately associated with the temporal regulation of inflammatory responses, with the resolution phase being associated with paracrine and autocrine melatonin effects. Such data suggest that the proven effects of exogenous melatonin in the resolution phase of inflammation are paralleled by the effects of locally synthesized melatonin in immune cells.

Melatonin attenuates Leishmania (L.) amazonensis infection by modulating arginine metabolism

Acute inflammatory responses induced by bacteria or fungi block nocturnal melatonin synthesis by rodent pineal glands. Here, we show Leishmania infection does not impair daily melatonin rhythm in hamsters. Remarkably, the attenuated parasite burden and lesion progression in hamsters infected at nighttime was impaired by blockage of melatonin receptors with luzindole, whereas melatonin treatment during the light phase attenuated Leishmania infection. In vitro studies corroborated in vivo observations. Melatonin treatment reduced macrophage expression of Cat-2b, Cat1, and ArgI, genes involved in arginine uptake and polyamine synthesis. Indeed, melatonin reduced macrophage arginine uptake by 40%. Putrescine supplementation reverted the attenuation of infectivity by melatonin indicating that its effect was due to the arrest of parasite replication. This study shows that the Leishmania/host interaction varies in a circadian manner according to nocturnal melatonin pineal synthesis. Our results provide new data regarding Leishmania infectiveness and show new approaches for applying agonists of melatonin receptors in Leishmaniasis therapy.

Neuroendocrine control of photoperiodic changes in immune function

Seasonal variation in immune function putatively maximizes survival and reproductive success. Day length (photoperiod) is the most potent signal for time of year. Animals typically organize breeding, growth, and behavior to adapt to spatial and temporal niches. Outside the tropics individuals monitor photoperiod to support adaptations favoring survival and reproductive success. Changes in day length allow anticipation of seasonal changes in temperature and food availability that are critical for reproductive success. Immune function is typically bolstered during winter, whereas reproduction and growth are favored during summer. We provide an overview of how photoperiod influences neuronal function and melatonin secretion, how melatonin acts directly and indirectly to govern seasonal changes in immune function, and the manner by which other neuroendocrine effectors such as glucocorticoids, prolactin, thyroid, and sex steroid hormones modulate seasonal variations in immune function. Potential future research avenues include commensal gut microbiota and light pollution influences on photoperiodic responses.

Early life exposure to undernutrition induces ER stress, apoptosis, and reduced vascularization in ovaries of adult rat offspring

Maternal nutritional restriction has been shown to induce impairments in a number of organ systems including the ovary. We have previously shown that maternal undernutrition induces fetal growth restriction and low birth weight, and results in an offspring ovarian phenotype characteristic of premature ovarian aging with reduced ovarian reserve. In the present study, we set out to investigate the underlying mechanisms that lead offspring of undernourished mothers to premature ovarian aging. Pregnant dams were randomized to 1) a standard diet throughout pregnancy and lactation (control), 2) a calorie-restricted (50% of control) diet during pregnancy, 3) a calorie-restricted (50% of control) diet during pregnancy and lactation, or 4) a calorie-restricted (50% of control) diet during lactation alone. The present study shows that early life undernutrition-induced reduction of adult ovarian follicles may be mediated by increased ovarian endoplasmic reticulum stress in a manner that increased follicular apoptosis but not autophagy. These changes were associated with a loss of ovarian vessel density and are consistent with an accelerated ovarian aging phenotype. Whether these changes are mediated specifically by a reduction in the local antioxidant environment is unclear, although our data suggest the possibility that ovarian melatonin may play a part in early life nutritional undernutrition and impaired offspring folliculogenesis.

Selective protection of the cerebellum against intracerebroventricular LPS is mediated by local melatonin synthesis

Although melatonin is mainly produced by the pineal gland, an increasing number of extra-pineal sites of melatonin synthesis have been described. We previously demonstrated the existence of bidirectional communication between the pineal gland and the immune system that drives a switch in melatonin production from the pineal gland to peripheral organs during the mounting of an innate immune response. In the present study, we show that acute neuroinflammation induced by lipopolysaccharide (LPS) injected directly into the lateral ventricles of adult rats reduces the nocturnal peak of melatonin in the plasma and induces its synthesis in the cerebellum, though not in the cortex or hippocampus. This increase in cerebellar melatonin content requires the activation of nuclear factor kappa B (NF-κB), which positively regulates the expression of the key enzyme for melatonin synthesis, arylalkylamine N-acetyltransferase (AA-NAT). Interestingly, LPS treatment led to neuronal death in the hippocampus and cortex, but not in the cerebellum. This privileged protection of cerebellar cells was abrogated when G-protein-coupled melatonin receptors were blocked by the melatonin antagonist luzindole, suggesting that the local production of melatonin protects cerebellar neurons from LPS toxicity. This is the first demonstration of a switch between pineal and extra-pineal melatonin production in the central nervous system following a neuroinflammatory response. These results have direct implications concerning the differential susceptibility of specific brain areas to neuronal death.

Immune-pineal axis: nuclear factor κB (NF-kB) mediates the shift in the melatonin source from pinealocytes to immune competent cells

Pineal gland melatonin is the darkness hormone, while extra-pineal melatonin produced by the gonads, gut, retina, and immune competent cells acts as a paracrine or autocrine mediator. The well-known immunomodulatory effect of melatonin is observed either as an endocrine, a paracrine or an autocrine response. In mammals, nuclear translocation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) blocks noradrenaline-induced melatonin synthesis in pinealocytes, which induces melatonin synthesis in macrophages. In addition, melatonin reduces NF-κB activation in pinealocytes and immune competent cells. Therefore, pathogen- or danger-associated molecular patterns transiently switch the synthesis of melatonin from pinealocytes to immune competent cells, and as the response progresses melatonin inhibition of NF-κB activity leads these cells to a more quiescent state. The opposite effect of NF-κB in pinealocytes and immune competent cells is due to different NF-κB dimers recruited in each phase of the defense response. This coordinated shift of the source of melatonin driven by NF-κB is called the immune-pineal axis. Finally, we discuss how this concept might be relevant to a better understanding of pathological conditions with impaired melatonin rhythms and hope it opens new horizons for the research of side effects of melatonin-based therapies.

The concept of the immune-pineal axis tested in patients undergoing an abdominal hysterectomy

OBJECTIVE

Activation of the immune-pineal axis induces a transient reduction in nocturnal melatonin in the plasma during the proinflammatory phase of an innate immune response to allow the proper migration of leukocytes to the lesion site. This transient reduction should be regulated by inflammatory mediators, which are responsible for the fine-tuning of the process. In the present study, we measured the pre- and postoperative serum concentrations of melatonin, tumor necrosis factor (TNF) and cortisol in women who underwent an elective hysterectomy and correlated the variation in melatonin with postoperative pain.

METHODS

We evaluated 12 women who had an abdominal hysterectomy. Blood was collected at 10.00 and 22.00 h 1 week and 1 day before the surgery, on the 1st and 2nd days after the surgery and at 22.00 h on the day of the surgery.

RESULTS

On the night after the surgery, there was no melatonin detected at 22.00 h. High TNF levels were accompanied by a lower nocturnal melatonin output, higher postoperative pain according to a visual analog scale and the request of higher doses of analgesics. In addition, low cortisol levels were accompanied by a lower nocturnal melatonin output.

CONCLUSION

Our results confirm that the same antagonistic pattern between TNF and glucocorticoids observed in cultured pineal glands also occurs in humans. This integrative pattern suggests that the cross talk between the immune and endocrine system orchestrates longitudinal changes in pineal activity, reinforcing the hypothesis of an immune-pineal axis.

Pineal arylalkylamine N-acetyltransferase (Aanat) gene expression as a target of inflammatory mediators in the chicken

Previously, we demonstrated that experimental peritonitis in chickens was attenuated by treatment with exogenous melatonin, while the developing inflammation decreased pineal AANAT activity. This suggested the existence of a bidirectional relationship between the activated immune system and pineal gland function. The aim of the present study was to identify the step(s) in the chicken pineal melatonin biosynthetic pathway that are affected by inflammation. Peritonitis was evoked by i.p. injection of thioglycollate solution, either 2h after the start, or 2h before the end of the light period, and the animals were sacrificed 4h later. The effect of inflammation on the expression of genes encoding enzymes participating in melatonin biosynthesis in the pineal gland, i.e. tryptophan hydroxylase 1 (Tph1), dopa decarboxylase (Ddc), arylalkylamine N-acetyltransferase (Aanat) and acetylserotonin O-methyltransferase (Asmt), was evaluated by qPCR. The pineal and serum melatonin concentration as well as the content of its precursors in the pineal gland were measured, along with the activity of the relevant biosynthetic enzymes. Developing peritonitis caused an increase in the pineal levels of the Tph1 mRNA during the night and the Asmt mRNA during the day, while nocturnal Aanat transcription was reduced. Both the pineal and serum melatonin level and the pineal content of N-acetylserotonin (NAS) were decreased during the night in birds with peritonitis. The amount and activity of pineal AANAT were significantly reduced, while the activity of HIOMT was increased under these experimental conditions. These results indicate that the observed decrease in MEL biosynthesis in chickens with developing inflammation is a result of transcriptional downregulation of the Aanat gene, followed by reduced synthesis and activity of the encoded enzyme.

Glia-pinealocyte network: the paracrine modulation of melatonin synthesis by tumor necrosis factor (TNF)

The pineal gland, a circumventricular organ, plays an integrative role in defense responses. The injury-induced suppression of the pineal gland hormone, melatonin, which is triggered by darkness, allows the mounting of innate immune responses. We have previously shown that cultured pineal glands, which express toll-like receptor 4 (TLR4) and tumor necrosis factor receptor 1 (TNFR1), produce TNF when challenged with lipopolysaccharide (LPS). Here our aim was to evaluate which cells present in the pineal gland, astrocytes, microglia or pinealocytes produced TNF, in order to understand the interaction between pineal activity, melatonin production and immune function. Cultured pineal glands or pinealocytes were stimulated with LPS. TNF content was measured using an enzyme-linked immunosorbent assay. TLR4 and TNFR1 expression were analyzed by confocal microscopy. Microglial morphology was analyzed by immunohistochemistry. In the present study, we show that although the main cell types of the pineal gland (pinealocytes, astrocytes and microglia) express TLR4, the production of TNF induced by LPS is mediated by microglia. This effect is due to activation of the nuclear factor kappa B (NF-kB) pathway. In addition, we observed that LPS activates microglia and modulates the expression of TNFR1 in pinealocytes. As TNF has been shown to amplify and prolong inflammatory responses, its production by pineal microglia suggests a glia-pinealocyte network that regulates melatonin output. The current study demonstrates the molecular and cellular basis for understanding how melatonin synthesis is regulated during an innate immune response, thus our results reinforce the role of the pineal gland as sensor of immune status.