GILZ-dependent modulation of mTORC1 regulates spermatogonial maintenance

Male fertility is dependent on spermatogonial stem cells (SSCs) that self-renew and produce differentiating germ cells. Growth factors produced within the testis are essential for SSC maintenance but intrinsic factors that dictate the SSC response to these stimuli are poorly characterised. Here, we have studied the role of GILZ, a TSC22D family protein and spermatogenesis regulator, in spermatogonial function and signalling. Although broadly expressed in the germline, GILZ was prominent in undifferentiated spermatogonia and Gilz deletion in adults resulted in exhaustion of the GFRα1⁺ SSC-containing population and germline degeneration. GILZ loss was associated with mTORC1 activation, suggesting enhanced growth factor signalling. Expression of deubiquitylase USP9X, an mTORC1 modulator required for spermatogenesis, was disrupted in Gilz mutants. Treatment with an mTOR inhibitor rescued GFRα1⁺ spermatogonial failure, indicating that GILZ-dependent mTORC1 inhibition is crucial for SSC maintenance. Analysis of cultured undifferentiated spermatogonia lacking GILZ confirmed aberrant activation of ERK MAPK upstream mTORC1 plus USP9X downregulation and interaction of GILZ with TSC22D proteins. Our data indicate an essential role for GILZ-TSC22D complexes in ensuring the appropriate response of undifferentiated spermatogonia to growth factors via distinct inputs to mTORC1.

Analysis of Serum Interleukin (IL)-1β and IL-18 in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by biological and clinical heterogeneity. The interleukin (IL)-1 superfamily is a group of innate cytokines that contribute to pathogenesis in many autoimmune diseases. IL-1β and IL-18 are two members that have been shown to play a role in murine lupus-like models, but their role in human SLE remains poorly understood. Here, IL-1β and IL-18 were quantified by enzyme-linked immunosorbent assay in the serum of healthy controls (HCs) and SLE patients from a prospectively followed cohort. Disease activity and organ damage were assessed using SLE disease activity index 2000 (SLEDAI-2K) and SLE damage index scores (SDI), respectively. 184 SLE patients (mean age 44.9 years, 91% female, 56% double-stranded deoxyribonucleic acid positive) were compared to 52 HC. SLE patients had median [IQR] SLEDAI-2K of 4 [2,6], and SDI of 1 [0–2]. Serum IL-18 levels were statistically significantly higher in SLE patients compared to HCs. Univariable linear regression analyses showed that patients with active renal disease or irreversible organ damage had statistically significantly elevated serum IL-18 levels. The association between serum IL-18 and active renal disease was confirmed in multivariable analysis after adjusting for ethnicity and organ damage. High baseline serum IL-18 levels were associated with organ damage at the subsequent visit. Serum IL-1β levels were not significantly elevated in SLE patients when compared to HCs and had no association with overall or organ-specific disease activity or organ damage in cross-sectional and longitudinal analyses. Our data suggest that serum IL-18 and IL-1β have different clinical implications in SLE, with IL-18 being potentially associated with active renal disease.

Author Correction: Endogenous Annexin-A1 Regulates Haematopoietic Stem Cell Mobilisation and Inflammatory Response Post Myocardial Infarction in Mice In Vivo

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Lupus Low Disease Activity State (LLDAS) attainment discriminates responders in a systemic lupus erythematosus trial: post-hoc analysis of the Phase IIb MUSE trial of anifrolumab

Objectives

In a post-hoc analysis, we aimed to validate the Lupus Low Disease Activity State (LLDAS) definition as an endpoint in an systemic lupus erythematosus (SLE) Phase IIb randomised controlled trial (RCT) (MUSE [NCT01438489]) and then utilize LLDAS to discriminate between anifrolumab and placebo.

Methods

Patients received intravenous placebo (n=102) or anifrolumab (300 mg, n=99; 1,000 mg, n=104) Q4W plus standard of care for 48 weeks. LLDAS attainment (SLE Disease Activity Index 2000 ≤4 without major organ activity, no new disease activity, Physician’s Global Assessment ≤1, prednisolone ≤7.5 mg/d and standard immunosuppressant dosage tolerance) was assessed. Associations with endpoints and LLDAS attainment differences between treatments were explored.

Results

LLDAS attainment at Week 52 was associated with SLE Responder Index 4 (SRI[4]) and British Isles Lupus Assessment Group–based Composite Lupus Assessment (BICLA) (74/85[87%] and 62/84[74%] were also SRI[4] and BICLA responders, respectively; both nominal p<0.001). Only 74/159 (47%) of SRI(4) and 62/121 (51%) of BICLA responders reached LLDAS.

Anifrolumab-treated patients achieved earlier LLDAS, and more spent at least half their observed time in LLDAS (OR vs. placebo; 300 mg: 3.04, 95% CI 1.34 to 6.92, nominal p=0.008; 1,000 mg: 2.17, 95% CI 0.93 to 5.03, nominal p=0.072) vs placebo-treated patients. At Week 52, 17/102 (17%), 39/99 (39%) and 29/104 (28%) of patients on placebo, anifrolumab 300 and 1,000 mg, respectively, attained LLDAS (OR vs. placebo; 300 mg: 3.41, 95% CI 1.73 to 6.76, p<0.001; 1,000 mg: 2.03, 95% CI 1.01 to 4.07, nominal p=0.046).

Conclusions

LLDAS attainment represents a clinically meaningful SLE outcome measure, and anifrolumab is associated with more patients who met LLDAS criteria versus placebo. These data support LLDAS as an SLE RCT endpoint.

Trial registration number

NCT1438489; Post-results.

Gilz-Activin A as a Novel Signaling Axis Orchestrating Mesenchymal Stem Cell and Th17 Cell Interplay

Mesenchymal stem cells (MSC) are highly immunosuppressive cells able to reduce chronic inflammation through the active release of mediators. Recently, we showed that glucocorticoid-induced leucine zipper (Gilz) expression by MSC is involved in their therapeutic effect by promoting the generation of regulatory T cells. However, the mechanisms underlying this pivotal role of Gilz remain elusive.

Methods and Results In this study, we have uncovered evidence that Gilz modulates the phenotype and function of Th1 and Th17 cells likely by upregulating the level of Activin A and NO₂ secreted by MSC. Adoptive transfer experiments sustained this Gilz-dependent suppressive effect of MSC on Th1 and Th17 cell functions. In immunoregulatory MSC, obtained by priming with IFN-γ and TNF-α, Gilz was translocated to the nucleus and bound to the promoters of inos and Activin βA to induce their expression. The increased expression of Activin A directly impacted on Th17 cells fate by repressing their differentiation program through the activation of Smad3/2 and enhancing IL-10 production.

Conclusion Our results reveal how Gilz controls inos and Activin βA gene expression to ultimately assign immunoregulatory status to MSC able to repress the pathogenic Th17 cell differentiation program and uncover Activin A as a novel mediator of MSC in this process.

Discordance of patient and physician health status concerns in systemic lupus erythematosus

Objectives To compare the health status concerns of patients with systemic lupus erythematosus (SLE) and of their physicians. Methods Cross-sectional questionnaire study of SLE patients and their treating physicians at a tertiary disease-specific outpatient clinic. Patients and physicians completed a questionnaire regarding their concern about specific disease manifestations and impact on quality of life. For each item, degree of concern was rated on a five-point Likert scale and summarized as median (interquartile range). Ratings between patients and physicians were compared using Mann-Whitney U tests. Results A total of 84 patients and 21 physicians participated. Patients' predominant concerns centred on function and fatigue, whereas physicians' concerns focused on SLE-related organ complications. Of the 10 highest ranked patient concerns, only two were common to the 10 highest ranked physician concerns, while physicians rated seven significantly differently; all 10 highest ranked physician concerns were rated significantly lower by patients. The three highest ranked patient concerns (fatigue, pain and feeling worn out) were routinely assessed by 47.6%, 42.9% and 9.5% of physicians, respectively. Conclusion There was significant discordance between SLE patient and physician health status concerns. Items which were ranked highly by patients were not assessed consistently by physicians, highlighting a significant gap in healthcare communication.

Cardiovascular risk profiles in a lupus cohort: what do different calculators tell us?

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide and this risk is increased in patients with SLE who may not conform to traditional cardiovascular risk profiles.

Aims

To determine the prevalence of high CVD risk among patients with SLE calculated using different risk calculators, and to characterise those identified as high risk.

Methods

A cross-sectional analysis to estimate CVD risk using the Framingham Risk Equation (Framingham score) and an SLE-specific CVD risk equation (SLE score) was undertaken using data from a single centre cohort. The characteristics of patients identified as 'high risk' by the SLE score only (the 'missed group') were compared with those identified by the Framingham score (the 'conventional group').

Results

146 patients were included; 22 (15%) and 44 (30%) were determined to be at 'high risk' based on the Framingham and SLE scores, respectively. Patients in the 'missed group' were less likely to have traditional risk factors and were more likely to be female (81% vs 50%; p=0.03), younger (mean age 54 vs 69 years p<0.01) and have lower systolic blood pressure (132 vs 143 mm Hg; p=0.05). Of those deemed high risk, only a minority were treated to target blood pressure and lipid levels.

Conclusions

A large proportion of patients with SLE could be re-classified as high risk using a formula that incorporates SLE disease-related parameters. These patients have different profiles to those identified using a conventional risk model. Optimal CVD risk assessment and management warrants further attention in SLE.

It hasn't gone away: the problem of glucocorticoid use in lupus remains

The treatment of SLE remains complex, and management is constrained by a lack of safe, effective, targeted therapies. Physicians, also, are constrained by a lack of evidence-based approaches with existing agents, including glucocorticoids, utilized in the majority of patients. While Cushingoid side effects of glucocorticoids are widely recognized, emerging literature now suggests that glucocorticoid use actually contributes to harmful outcomes in SLE, over and above these effects. These studies provide a compelling case for a re-evaluation of the long-term use of glucocorticoids in SLE, focusing on minimizing glucocorticoid exposure as part of the strategy to improve long-term outcomes. In this article, we review the evidence for the harmful effects of glucocorticoids in SLE, and propose therapeutic options that reduce reliance on glucocorticoids. We propose that it is time for the lupus community to have a louder conversation about glucocorticoid use, and for any residual complacency about their risk-benefit ratio to be banished.

Quality of Care for Systemic Lupus Erythematosus: Mind the Knowledge Gap

Systemic lupus erythematosus (SLE) is a prototypical chronic multiorgan autoimmune disorder that can lead to significant burden of disease and loss of life expectancy. The disease burden is the result of a complex interplay between genetic, biologic, socioeconomic, and health system variables affecting the individual. Recent advances in biological understanding of SLE are yet to translate to transformative therapies, and genetic and socioeconomic variables are not readily amenable to intervention. In contrast, healthcare quality, a variable readily amenable to change, has been inadequately addressed in SLE, despite evidence in other chronic diseases that quality of care is strongly associated with patient outcomes. This article will analyze the available literature on the quality of care relevant to SLE, identify knowledge gaps, and suggest ways to address this in future research.

Independent association of glucocorticoids with damage accrual in SLE

Objectives

To determine factors associated with damage accrual in a prospective cohort of patients with SLE.

Methods

Patients with SLE who attended the Lupus Clinic at Monash Health, Australia, between 2007 and 2013 were studied. Clinical variables included disease activity (Systemic Lupus Erythematosus Disease Activity Index-2K, SLEDAI-2K), time-adjusted mean SLEDAI, cumulative glucocorticoid dose and organ damage (Systemic Lupus International Collaborating Clinics Damage Index (SDI)). Multivariate logistic regression analyses were performed to identify factors associated with damage accrual.

Results

A total of 162 patients were observed over a median (IQR) 3.6 (2.0–4.7) years. Seventy-five per cent (n=121) of patients received glucocorticoids. Damage accrual was significantly more frequent in glucocorticoid-exposed patients (42% vs 15%, p<0.01). Higher glucocorticoid exposure was independently associated with overall damage accrual after controlling for factors including ethnicity and disease activity and was significant at time-adjusted mean doses above 4.42 mg prednisolone/day; the OR of damage accrual in patients in the highest quartile of cumulative glucocorticoid exposure was over 10. Glucocorticoid exposure was independently associated with damage accrual in glucocorticoid-related and non-glucocorticoid related domains of the SDI.

Conclusions

Glucocorticoid use is independently associated with the accrual of damage in SLE, including in non-glucocorticoid related domains.

Clinical associations of IL-10 and IL-37 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the development of autoantibodies to nuclear antigens and inflammatory responses mediated by multiple cytokines. Although previous studies have determined clinical associations between SLE and the anti-inflammatory cytokines IL-10 and IL-37, their role in the disease, or their potential as biomarkers, remains unclear. We examined serum levels of IL-10 and IL-37 in a large cohort of SLE patients, with detailed longitudinal clinical data. We demonstrate a statistically significant association of serum IL-10 with disease activity, with higher levels in active compared to inactive disease. High first visit IL-10 was predictive of high subsequent disease activity; patients with IL-10 in highest quartile at first visit were 3.6 times more likely to have active disease in subsequent visits. Serum IL-37 was also higher in SLE patients compared to control, and was strongly associated with Asian ethnicity. However, IL-37 was not statistically significantly associated with disease activity. IL-37 was significantly reduced in patients with organ damage but this association was attenuated in multivariable analysis. The data suggest that IL-10, but not IL-37, may have potential as a biomarker predictive for disease activity in SLE.

Validation of the Lupus Impact Tracker in an Australian patient cohort

OBJECTIVES

The objective of this article is to validate the Lupus Impact Tracker (LIT), a disease-specific patient-reported outcome (PRO) tool, in systemic lupus erythematosus (SLE) patients in a multi-ethnic Australian cohort.

METHODS

Patients attending the Monash Lupus Clinic were asked to complete the LIT, a 10-item PRO. Psychometric testing assessing criterion validity, construct validity, test-retest reliability (TRT) and internal consistency reliability (ICR) were performed. We compared the LIT scores across patient characteristics, and correlations between LIT scores and SLEDAI-2k, PGA, and SLICC-SDI were examined.

RESULTS

LIT data were obtained from 73 patients. Patients were 84% female with a median age of 41 years, and 34% were Asian. The cohort had mild-moderate disease activity with a median (IQR) Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2k) of 4 (IQR 2-6). The median LIT score was 32.5 (IQR 17.5-50). LIT demonstrated criterion validity against SLEDAI-2k and SDI. Construct validity assessed by confirmatory factor analysis demonstrated an excellent fit (Goodness of fit index 0.95, Comparative Fit Index 1, Root Mean Square Error of Approximation <0.0001). The LIT demonstrated TRT with an overall intraclass correlation coefficient of 0.986 (95% CI 0.968-0.995). ICR was demonstrated with a Cronbach's alpha of 0.838. Patients with disability, low socioeconomic status, or higher disease activity had significantly worse LIT scores.

CONCLUSION

The LIT demonstrated properties consistent with its being valid in this population. Lower socioeconomic status appears to have a significant impact on patient-reported health-related quality of life in SLE.

Association of MIF, but not type I interferon-induced chemokines, with increased disease activity in Asian patients with systemic lupus erythematosus

Ethnicity is a key factor impacting on disease severity in SLE, but molecular mechanisms of these associations are unknown. Type I IFN and MIF have each been associated with SLE pathogenesis. We investigated whether increased SLE severity in Asian patients is associated with either MIF or Type I IFN. SLE patients (n = 151) had prospective recording of disease variables. Serum MIF, and a validated composite score of three Type I IFN-inducible chemokines (IFNCK:CCL2, CXCL10, CCL19) were measured. Associations of MIF and IFNCK score with disease activity were assessed, with persistent active disease (PAD) used as a marker of high disease activity over a median 2.6 years follow up. In univariable analysis, MIF, IFNCK score and Asian ethnicity were significantly associated with PAD. Asian ethnicity was associated with higher MIF but not IFNCK score. In multivariable logistic regression analysis, MIF (OR3.62 (95% CI 1.14,11.5), p = 0.03) and Asian ethnicity (OR3.00 (95% CI 1.39,6.46), p < 0.01) but not IFNCK were significantly associated with PAD. These results potentially support an effect of MIF, but not Type I IFN, in heightened SLE disease severity in Asian SLE. The associations of MIF and Asian ethnicity with PAD are at least partly independent.

Loss of autophagy enhances MIF/macrophage migration inhibitory factor release by macrophages

MIF (macrophage migration inhibitory factor [glycosylation-inhibiting factor]) is a pro-inflammatory cytokine expressed in multiple cells types, including macrophages. MIF plays a pathogenic role in a number of inflammatory diseases and has been linked to tumor progression in some cancers. Previous work has demonstrated that loss of autophagy in macrophages enhances secretion of IL1 family cytokines. Here, we demonstrate that loss of autophagy, by pharmacological inhibition or siRNA silencing of Atg5, enhances MIF secretion by monocytes and macrophages. We further demonstrate that this is dependent on mitochondrial reactive oxygen species (ROS). Induction of autophagy with MTOR inhibitors had no effect on MIF secretion, but amino acid starvation increased secretion. This was unaffected by Atg5 siRNA but was again dependent on mitochondrial ROS. Our data demonstrate that autophagic regulation of mitochondrial ROS plays a pivotal role in the regulation of inflammatory cytokine secretion in macrophages, with potential implications for the pathogenesis of inflammatory diseases and cancers.

Brief Report: Interleukin-38 Exerts Antiinflammatory Functions and Is Associated With Disease Activity in Systemic Lupus Erythematosus

OBJECTIVE

Knowledge of interleukin-38 (IL-38), formerly IL-1 family member 10, is sparse, but Il1f10 polymorphisms are associated with inflammatory diseases, and recombinant IL-38 inhibits inflammatory responses similar to those reported in the context of systemic lupus erythematosus (SLE). We undertook this study to explore the function of endogenous IL-38 in human peripheral blood mononuclear cells (PBMCs) as well as its abundance in serum in a well-characterized cohort of SLE patients.

METHODS

Serum IL-38 and IL-10 levels were quantified by enzyme-linked immunosorbent assay in 142 SLE patients at ≤3 consecutive visits and in 28 healthy volunteers. To assess IL-38 function, we silenced IL-38 in PBMCs from healthy donors using IL-38 small interfering RNA (siRNA).

RESULTS

IL-38 (63-5,928 pg/ml) was detectable in 16% of 372 serum samples. IL-38 abundance was significantly higher in samples from SLE patients than in samples from healthy controls (P = 0.004) and 11-fold higher in patients with active disease (SLE Disease Activity Index 2000 [SLEDAI-2K] score of ≥4) than in those with inactive disease (SLEDAI-2K score of <4) (P = 0.044). Importantly, IL-38 detection was associated with increased risk of renal lupus (relative risk [RR] 1.6, P = 0.027) and central nervous system lupus (RR 2.3, P = 0.034), and detectable baseline IL-38 entailed a 1.6-fold increased risk of subsequently meeting criteria for persistently active disease (P = 0.0097). Longitudinal time-adjusted mean IL-38 concentration was also 6-fold higher in patients with persistently active disease than in those without (P = 0.023). Remarkably, PBMCs treated with IL-38 siRNA produced up to 28-fold more of the proinflammatory mediators IL-6, CCL2, and APRIL than did control siRNA-transfected cells upon stimulation with Toll-like receptor agonists. Similarly, in SLE patients, the antiinflammatory cytokine IL-10 was 5-fold more abundant when IL-38 was detectable.

CONCLUSION

This is the first study of the function of endogenous IL-38, and the data suggest that IL-38 may be protective in SLE. A strong association between IL-38 and SLE severity suggests that IL-38 expression is driven by processes linked to SLE pathogenesis. Exploitation of the regulatory effects of IL-38 may represent a promising therapeutic strategy in SLE.

Glucocorticoid-induced leucine zipper (GILZ) inhibits B cell activation in systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is a serious multisystem autoimmune disease, mediated by disrupted B cell quiescence and typically treated with glucocorticoids. We studied whether B cells in SLE are regulated by the glucocorticoid-induced leucine zipper (GILZ) protein, an endogenous mediator of anti-inflammatory effects of glucocorticoids.

METHODS

We conducted a study of GILZ expression in blood mononuclear cells of patients with SLE, performed in vitro analyses of GILZ function in mouse and human B cells, assessed the contributions of GILZ to autoimmunity in mice, and used the nitrophenol coupled to keyhole limpet haemocyanin model of immunisation in mice.

RESULTS

Reduced B cell GILZ was observed in patients with SLE and lupus-prone mice, and impaired induction of GILZ in patients with SLE receiving glucocorticoids was associated with increased disease activity. GILZ was downregulated in naïve B cells upon stimulation in vitro and in germinal centre B cells, which contained less enrichment of H3K4me3 at the GILZ promoter compared with naïve and memory B cells. Mice lacking GILZ spontaneously developed lupus-like autoimmunity, and GILZ deficiency resulted in excessive B cell responses to T-dependent stimulation. Accordingly, loss of GILZ in naïve B cells allowed upregulation of multiple genes that promote the germinal centre B cell phenotype, including lupus susceptibility genes and genes involved in cell survival and proliferation. Finally, treatment of human B cells with a cell-permeable GILZ fusion protein potently suppressed their responsiveness to T-dependent stimuli.

CONCLUSIONS

Our findings demonstrated that GILZ is a non-redundant regulator of B cell activity, with important potential clinical implications in SLE.

MIF: Implications in the Pathoetiology of Systemic Lupus Erythematosus

Macrophage migration Inhibitory factor (MIF) was one of the earliest pro-inflammatory cytokines to be identified. Increasing interest in this cytokine in recent decades has followed the cloning of human MIF and the generation of Mif^−/− mice. Deepening understanding of signaling pathways utilized by MIF and putative receptor mechanisms have followed. MIF is distinct from all other cytokines by virtue of its unique induction by and counter regulation of glucocorticoids (GCs). MIF is further differentiated from other cytokines by its structural homology to specific tautomerase and isomerase enzymes and correlative in vitro enzymatic functions. The role of MIF in immune and inflammatory states, including a range of human autoimmune diseases, is now well established, as are the relationships between MIF polymorphisms and a number of inflammatory diseases. Here, we review the known pleiotropic activities of MIF, in addition to novel functions of MIF in processes including autophagy and autophagic cell death. In addition, recent developments in the understanding of the role of MIF in systemic lupus erythematosus (SLE) are reviewed. Finally, we discuss the potential application of anti-MIF strategies to treat human diseases such as SLE, which will require a comprehensive understanding of the unique and complex activities of this ubiquitously expressed cytokine.

Definition and initial validation of a Lupus Low Disease Activity State (LLDAS)

Aims

Treating to low disease activity is routine in rheumatoid arthritis, but no comparable goal has been defined for systemic lupus erythematosus (SLE). We sought to define and validate a Lupus Low Disease Activity State (LLDAS).

Methods

A consensus definition of LLDAS was generated using Delphi and nominal group techniques. Criterion validity was determined by measuring the ability of LLDAS attainment, in a single-centre SLE cohort, to predict non-accrual of irreversible organ damage, measured using the Systemic Lupus International Collaborating Clinics Damage Index (SDI).

Results

Consensus methodology led to the following definition of LLDAS: (1) SLE Disease Activity Index (SLEDAI)-2K ≤4, with no activity in major organ systems (renal, central nervous system (CNS), cardiopulmonary, vasculitis, fever) and no haemolytic anaemia or gastrointestinal activity; (2) no new lupus disease activity compared with the previous assessment; (3) a Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA)-SLEDAI physician global assessment (scale 0–3) ≤1; (4) a current prednisolone (or equivalent) dose ≤7.5 mg daily; and (5) well tolerated standard maintenance doses of immunosuppressive drugs and approved biological agents. Achievement of LLDAS was determined in 191 patients followed for a mean of 3.9 years. Patients who spent greater than 50% of their observed time in LLDAS had significantly reduced organ damage accrual compared with patients who spent less than 50% of their time in LLDAS (p=0.0007) and were significantly less likely to have an increase in SDI of ≥1 (relative risk 0.47, 95% CI 0.28 to 0.79, p=0.005).

Conclusions

A definition of LLDAS has been generated, and preliminary validation demonstrates its attainment to be associated with improved outcomes in SLE.