Clinical Experience of Sirolimus Regarding Efficacy and Safety in Systemic Lupus Erythematosus

Sirolimus as a repurposed drug for tendinopathy: A systems biology approach combining computational and experimental methods

BACKGROUND

Effective drugs for tendinopathy are lacking, resulting in significant morbidity and re-tearing rate after operation. Applying systems biology to identify new applications for current pharmaceuticals can decrease the duration, expenses, and likelihood of failure associated with the development of new drugs.

METHODS

We identify tendinopathy signature genes employing a transcriptomics database encompassing 154 clinical tendon samples. We then proposed a systems biology based drug prediction strategy that encompassed multiplex transcriptional drug prediction, systematic review assessment, deep learning based efficacy prediction and Mendelian randomization (MR). Finally, we evaluated the effects of drug target using gene knockout mice.

RESULTS

We demonstrate that sirolimus is a repurposable drug for tendinopathy, supported by: 1) Sirolimus achieves top ranking in drug-gene signature-based multiplex transcriptional drug efficacy prediction, 2) Consistent evidence from systematic review substantiates the efficacy of sirolimus in the management of tendinopathy, 3) Genetic prediction indicates that plasma proteins inhibited by mTOR (the target of sirolimus) are associated with increased tendinopathy risk. The effectiveness of sirolimus is further corroborated through in vivo testing utilizing tendon tissue-specific mTOR gene knockout mice. Integrative pathway enrichment analysis suggests that mTOR inhibition can regulate heterotopic ossification-related pathways to ameliorate clinical tendinopathy.

CONCLUSIONS

Our study assimilates knowledge of system-level responses to identify potential drugs for tendinopathy, and suggests sirolimus as a viable candidate. A systems biology approach could expedite the repurposing of drugs for human diseases that do not have well-defined targets.

Immunosuppressants against acute kidney injury: what to prefer or to avoid?

BACKGROUND

Acute kidney injury (AKI) is a critical global health issue associated with high mortality rates, particularly in patients undergoing renal transplants and major surgeries. These individuals often receive immunosuppressants to dampen immune responses, but the impact of these drugs on AKI remains unclear.

OBJECTIVE

This review aims to provide a detailed understanding of the effects of different classes of immunosuppressants against AKI, elucidating their role in either exacerbating or mitigating the occurrence or progression of AKI.

METHODS

Several preclinical and clinical reports were analyzed to evaluate the impact of various immunosuppressants on AKI. Relevant preclinical and clinical studies were reviewed through different databases such as Scopus, PubMed, Google Scholar, and ScienceDirect, and official websites like https://clinicaltrials.gov to understand the mechanisms underlying the effects of immunosuppressants on kidney function.

RESULTS AND DISCUSSION

Specific immunosuppressants have been linked to the progression of AKI, while others demonstrate renoprotective effects. However, there is no consensus on the preferred or avoided immunosuppressants for AKI patients. This review outlines the classes of immunosuppressants commonly used and their impact on AKI, providing guidance for physicians in selecting appropriate drugs to prevent or ameliorate AKI.

CONCLUSION

Understanding the effects of immunosuppressants on AKI is crucial for optimizing patient care. This review highlights the need for further research to determine the most suitable immunosuppressants for AKI patients, considering both their efficacy and potential side effects.

Advances in the pharmacological management of systemic lupus erythematosus

INTRODUCTION

Despite setbacks in clinical trials for systemic lupus erythematosus (SLE), three drugs have been approved for SLE and lupus nephritis (LN) treatment in the past decade. Several ongoing clinical trials, some viewed optimistically by the scientific community, underscore the evolving landscape. Emerging clinical data have established specific therapeutic targets in routine clinical practice for treating SLE, aiming to improve long-term outcomes.

AREAS COVERED

Research related to treatment of SLE and LN is discussed, focusing on randomized clinical trials during the last 5 years and recommendations for the management of SLE published by the European Alliance of Associations for Rheumatology (EULAR), American College of Rheumatology (ACR), Asia Pacific League of Associations for Rheumatology (APLAR), and Pan-American League of Associations of Rheumatology (PANLAR).

EXPERT OPINION

The landscape of SLE and LN treatments is evolving, as new drugs and combination treatment approaches redefine the traditional concepts of induction and maintenance treatment phases. As the therapeutic armamentarium in SLE continues to expand, the research focus is shifting from the imperative for new therapies to advancing our understanding of optimal treatment selection for individual patients, steering toward precision medicine strategies.

Add-on sirolimus for the treatment of mild or moderate systemic lupus erythematosus via T lymphocyte subsets balance

OBJECTIVE

The efficacy of sirolimus in treating severe or refractory systemic lupus erythematosus (SLE) has been confirmed by small-scale clinical trials. However, few studies focused on mild or moderate SLE. Therefore, in this study we elucidated clinical efficacy of add-on sirolimus in patients with mild or moderate SLE.

METHODS

Data of 17 consecutive patients with SLE were retrospectively collected. SLE Disease Activity Index-2000 (SLEDAI-2K), clinical manifestation, laboratory data and peripheral T lymphocyte subsets with cytokines were collected before and 6 months after sirolimus add-on treatment. T cell subsets were detected by flow cytometry and cytokines were determined by multiplex bead-based flow fluorescent immunoassay simultaneously. Twenty healthy controls matched with age and sex were also included in our study.

RESULTS

(1) The numbers of peripheral blood lymphocytes, T cells, T helper (Th) cells, regulatory T (Treg) cells, Th1 cells, Th2 cells and Treg/Th17 ratios in patients with SLE were significantly lower, while the numbers of Th17 cells were evidently higher than those of healthy control (p<0.05). (2) After 6 months of sirolimus add-on treatment, urinary protein, pancytopenia, immunological indicators and SLEDAI-2K in patients with SLE were distinctively improved compared with those before sirolimus treatment (p<0.05). (3) The numbers of peripheral blood lymphocytes, T cells, Th cells, Treg cells, Th2 cells and the ratios of Treg/Th17 in patients with SLE after treatment were clearly higher than those before (p<0.05). (4) The levels of plasma interleukin (IL)-5, IL-6 and IL-10 in patients with SLE decreased notably, conversely the IL-4 levels increased remarkably compared with pretreatment (p<0.05).

CONCLUSIONS

(1) Patients with SLE presented imbalanced T cell subsets, especially the decreased ratio of Treg/Th17. (2) Sirolimus add-on treatment ameliorated clinical involvement, serological abnormalities and disease activity without adverse reactions in patients with SLE. (3) The multi-target therapy facilitates the enhanced numbers of Treg cells, Treg/Th17 imbalance and anti-inflammatory cytokines, simultaneously, reducing inflammatory cytokines.

Local Injection of Rapamycin-Loaded Pcl-Peg Nanoparticles for Enhanced Tendon Healing in Rotator Cuff Tears via Simultaneously Reducing Fatty Infiltration and Drug Toxicity

As a common cause of shoulder pain, rotator cuff tears (RCTs) are difficult to treat clinically because of their unsatisfactory prognosis due to the fatty infiltration caused by muscle-derived stem cells (MDSCs). Previous studies have found that rapamycin (RAPA) can inhibit fatty infiltration. However, systemic administration of RAPA may cause complications such as infection and nausea, while local administration of RAPA may lead to the cytotoxicity of tendon cells, affecting the healing of rotator cuffs. In this study, biocompatible and clinically approved polycaprolactone-polyethylene glycol (PCL-PEG) is formulated into an injectable nanoparticle for the sustained release of RAPA. The results indicate that the RAPA/PCL-PEG nanoparticles (NPs) can efficiently prolong the release of RAPA and significantly reduce the cytotoxicity of tendon cells caused by RAPA. The study of the fatty infiltration model in rats with delayed rotator cuff repair shows that weekly intraarticular injection of RAPA/PCL-PEG NPs can more effectively reduce the fatty infiltration and muscle atrophy of rat rotator cuffs and leads to better mechanical properties and gait improvements than a daily intraarticular injection of RAPA. These findings imply that local injection of RAPA/PCL-PEG NPs in the shoulder joints can be a potential clinical option for RCTs patients with fatty infiltration.

Refractory systemic lupus erythematosus with chylous effusion successfully treated with sirolimus: a case report and literature review

Chylous effusion is a rare manifestation of systemic lupus erythematosus (SLE). When it does occur in SLE, it is generally well treated with standard pharmacologic or surgical measures. We present a decade of management in a case of SLE with lung affliction and development of refractory bilateral chylous effusion and pulmonary arterial hypertension (PAH). In the first years, the patient was treated under a Sjogren syndrome diagnose. After few years, her respiratory condition worsened due to chylous effusion and PAH. Immunosuppression therapy (methylprednisolone) was reintroduced, and vasodilator therapy commenced. With this, her cardiac function remained stable, but respiratory function continuously worsened despite several therapy trials with different combinations of immunosuppressant (glucocorticoids, resochin, cyclophosphamide and mycophenolate mofetil). On top of pleural effusion worsening, the patient developed ascites and severe hypoalbuminaemia. Even though albumin loss was stabilized with monthly octreotide applications, the patient remained respiratory insufficient and in need of continuous oxygen therapy. At that point, we decided to introduce sirolimus on top of glucocorticoids and mycophenolate mofetil therapy. Her clinical status, radiological finding, and lung function gradually improved and she became respiratory sufficient at rest. The patient remains in our follow-up and has been stable on given therapy for over 3 years despite overcoming a severe COVID-19 pneumonia in 2021. This case adds to the body of evidence of sirolimus effectiveness in patients with refractory systemic lupus and is, to our best knowledge, the first case to report its successful application in a patient with SLE and refractory chylous effusion.

Modulation of the immunity and inflammation by autophagy

Autophagy, a highly conserved cellular self-degradation pathway, has emerged with novel roles in the realms of immunity and inflammation. Genome-wide association studies have unveiled a correlation between genetic variations in autophagy-related genes and heightened susceptibility to autoimmune and inflammatory diseases. Subsequently, substantial progress has been made in unraveling the intricate involvement of autophagy in immunity and inflammation through functional studies. The autophagy pathway plays a crucial role in both innate and adaptive immunity, encompassing various key functions such as pathogen clearance, antigen processing and presentation, cytokine production, and lymphocyte differentiation and survival. Recent research has identified novel approaches in which the autophagy pathway and its associated proteins modulate the immune response, including noncanonical autophagy. This review provides an overview of the latest advancements in understanding the regulation of immunity and inflammation through autophagy. It summarizes the genetic associations between variants in autophagy-related genes and a range of autoimmune and inflammatory diseases, while also examining studies utilizing transgenic animal models to uncover the in vivo functions of autophagy. Furthermore, the review delves into the mechanisms by which autophagy dysregulation contributes to the development of three common autoimmune and inflammatory diseases and highlights the potential for autophagy-targeted therapies.

B cell activation via immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease involving multiple organs in which B cells perform important functions such as antibody and cytokine production and antigen presentation. B cells are activated and differentiated by the primary B cell receptor, co-stimulatory molecule signals-such as CD40/CD40L-, the Toll-like receptors 7,9, and various cytokine signals. The importance of immunometabolism in the activation, differentiation, and exerting functions of B cells and other immune cells has been widely reported in recent years. However, the regulatory mechanism of immunometabolism in B cells and its involvement in SLE pathogenesis remain elusive. Similarly, the importance of the PI3K-Akt-mTOR signaling pathway, glycolytic system, and oxidative phosphorylation has been demonstrated in the mechanisms of B cell immunometabolic activation, mainly in mouse studies. However, the activation of the mTOR pathway in B cells in patients with SLE, the induction of plasmablast differentiation through metabolic and transcription factor regulation by mTOR, and the involvement of this phenomenon in SLE pathogenesis are unclear. In our studies using activated B cells derived from healthy donors and from patients with SLE, we observed that methionine, an essential amino acid, is important for mTORC1 activation. Further, we observed that splenic tyrosine kinase and mTORC1 activation synergistically induce EZH2 expression and plasmablasts by suppressing BACH2 expression through epigenomic modification. Additionally, we identified another mechanism by which the glutaminolysis-induced enhancement of mitochondrial function promotes plasmablast differentiation in SLE. In this review, we focused on the SLE exacerbation mechanisms related to the activation of immune cells-especially B cells-and immunometabolism and reported the latest findings in the field.

New insights into the metabolism of Th17 cells

T helper 17 (Th17) cells are IL-17-producing CD4 T cells that play a crucial role in autoimmune diseases. IL-17 is a key cytokine for host protection against mucosal and skin infection but is also one of the major pathogenic cytokines. IL-1 and IL-23 are requisite for stimulating pathogenic Th17 cell differentiation and proliferation. Therapeutics targeting the IL-17/IL-23 pathway are widely used clinically for the treatment of autoimmune diseases. Besides IL-17, pathogenic Th17 cells produce granulocyte-macrophage colony-stimulating factor, tumor necrosis factor α, interferon γ, IL-21 and IL-22. However, Th17-targeted therapy has not yet been established. T cell metabolism orchestrates T cell survival, cell differentiation, epigenetic change and function and each T cell subset favors a particular metabolic pathway. Recent studies have provided novel insights into the role of T cell metabolism in the pathogenesis of autoimmune diseases. The current review focuses on the role of Th17 cell metabolism in autoimmune diseases, particularly glycolysis, amino acid metabolism, lipid metabolism, as well as the regulators of these processes, including mTORC1. Therapeutics targeting T cell metabolism in autoimmune diseases could serve as a possible treatment option for patients who are refractory to or unresponsive to conventional therapy.

A mechanistic target of rapamycin inhibitor, everolimus safely ameliorated lupus nephritis in a patient complicated with tuberous sclerosis

A 26-year-old woman with tuberous sclerosis complex (TSC) received outpatient treatment for the complication of systemic lupus erythematosus (SLE) at our hospital. She visited our hospital with a chief complaint of pitting oedema in bilateral lower legs for 3 days. The urinalysis showed massive proteinuria with a lot of white blood cell casts. The blood tests revealed hypoalbuminaemia, hypercholesterolaemia, hypocomplementaemia, and elevated anti-double-stranded DNA antibody titre. Renal biopsy was not performed because of multiple renal angiomyolipomas, which was one of the features of TSC. She was diagnosed with a nephrotic state due to lupus nephritis. Although she had a standard therapy with high-dose corticosteroid and mycophenolate mofetil and tacrolimus, complete remission had not been achieved leading to a steroid-dependent nephrotic syndrome. During the follow-up, the angiomyolipomas became larger and had a risk of rupture at the age of 29 years. Everolimus, a mechanistic target of rapamycin (mTOR) inhibitor, was started for the treatment of angiomyolipomas, and mycophenolate mofetil and tacrolimus were terminated instead. The activity of lupus nephritis was surprisingly ameliorated, and the amount of corticosteroid successfully tapered. Everolimus has been continued for 6 years without severe side effects. Accumulating evidence suggests that the activated mTOR pathway plays a key role in the pathogenesis of SLE. We reported the long-term efficacy and safety of everolimus for refractory SLE in a patient with TSC for the first time. This case suggests that everolimus can be a promising option for the treatment of lupus nephritis.

Clinical efficacy and safety of sirolimus in childhood-onset systemic lupus erythematosus in real world

To investigate the effectiveness and safety of sirolimus in childhood-onset systemic lupus erythematosus in a real world. This is a retrospective real world clinical study. All childhood-onset systemic lupus erythematosus patients treated with sirolimus in Children's Hospital of Hebei Province China were analyzed. They were treated with sirolimus and followed up regularly. The patients had systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, levels of antidouble-stranded DNA antibody, complement components C3 and C4, 24-hour proteinuria and corticosteroid reduction were recorded at baseline and at 6, 12, and 18 months. Adverse events were also collected. Thirty-two patients were enrolled in the study. SLEDAI-2K were improved on all time-points (P < .05). Complement levels increased and the levels of antidouble-stranded DNA antibody decreased during treatment. The mean dose of prednisone tapered and achieved significant reduction after 12 months therapy (15.4 ± 5.8 mg/d to 4.8 ± 2.1 mg/d; P < .05). Sirolimus was well tolerated and only 5 patients (15.6%) experienced adverse events, all of which were classified as infections (2 bacterial infection and 3 viral infections). No deaths, severe infusion reactions, or hypersensitivity reactions were found. Sirolimus use was associated with a decrease in disease activity and ability to tolerate tapering of oral glucocorticoid dose with a favorable risk-benefit profile.

Predicting the effect of sirolimus on disease activity in patients with systemic lupus erythematosus using machine learning

WHAT IS KNOWN AND OBJECTIVES

The present study aimed to predict the effect of sirolimus on disease activity in patients with systemic lupus erythematosus (SLE) using machine learning and to recommend appropriate sirolimus dosage regimen for patients with SLE.

METHODS

The E_max model was selected for machine learning, where the evaluation indicator was the change rate of systemic lupus erythematosus disease activity index from baseline value.

RESULTS

A total 103 patients with SLE were included for modelling, where the E_max , ET₅₀ were -53.9%, 1.53 months in the final model respectively, and the evaluation of the final model was good. Further simulation found that the follow-up time to achieve 25%, 50%, 75% and 80% (plateau) E_max of sirolimus effecting on disease activity in patients with SLE were 0.51, 1.53, 4.59 and 6.12 months, respectively. In addition, the sirolimus dosage was flexible and adjusted according to drug concentration, where the intersection of sirolimus concentration range included in this study was about 8-10 ng/ml.

WHAT IS NEW AND CONCLUSIONS

This study was the first time to predict the effect of sirolimus on disease activity in patients with SLE and in order to achieve better therapeutic effect maintaining a concentration of 8-10 ng/ml sirolimus for at least 6.12 months was necessary.

Autophagy and Skin Diseases

Autophagy is a highly conserved lysosomal degradation system that involves the creation of autophagosomes, which eventually fuse with lysosomes and breakdown misfolded proteins and damaged organelles with their enzymes. Autophagy is widely known for its function in cellular homeostasis under physiological and pathological settings. Defects in autophagy have been implicated in the pathophysiology of a variety of human diseases. The new line of evidence suggests that autophagy is inextricably linked to skin disorders. This review summarizes the principles behind autophagy and highlights current findings of autophagy's role in skin disorders and strategies for therapeutic modulation.

Successful treatment of sirolimus in a Chinese patient with refractory LN and APS: a case report

It has been reported that the mammalian target of rapamycin (mTOR) pathway is involved in the pathogenesis of systemic lupus erythematosus (SLE), and increasing evidence has shown the effect of mTOR-targeted therapies with sirolimus in SLE. The objective of this study was to report the successful treatment of sirolimus in a Chinese patient with refractory lupus nephritis (LN) and anti-phospholipid antibody syndrome (APS). A 44-year-old female with a previous diagnosis of autoimmune hemolytic anemia (AIHA) and APS secondary to SLE presented with lupus nephritis refractory to cyclophosphamide and mycophenolate. Renal biopsy met the criteria of WHO class III LN complicated by acute tubular injury and immunofluorescence confirmed the activation of the mTOR pathway. Treatment with the mTOR inhibitor sirolimus was initiated in this patient. Complete remission (CR) was achieved after 6 months, and flare-free remission was maintained for the next 3.5 years. The literature on the efficacy of sirolimus in patients with LN was reviewed. Although the available evidence is limited to retrospective studies with small sample sizes, sirolimus appeared to be efficacious in some patients with refractory LN. Well-designed clinical trials are warranted, and pathology-guided precision medicine might assist in guiding physicians’ treatment decisions.

Sirolimus versus tacrolimus for systemic lupus erythematosus treatment: results from a real-world CSTAR cohort study

OBJECTIVE

The effectiveness and safety of sirolimus for SLE treatment have been shown in some uncontrolled studies. However, a comparison of sirolimus with other classic immunosuppressants has not been reported. We conducted the study to compare the effectiveness and safety of sirolimus versus tacrolimus for SLE treatment.

METHODS

A real-world cohort study was conducted. Patients with clinically active SLE who were prescribed sirolimus or tacrolimus were enrolled. Propensity score matching was used to ensure equivalent disease conditions and background medications. SLE disease activity indices, serological parameters, steroid doses, modification of other immunosuppressants, renal effectiveness and adverse events were compared between the two groups at 3-month, 6-month, 9-month and 12-month follow-up visits.

RESULTS

Data from 52 patients in each of the sirolimus and tacrolimus groups were analysed. Indices regarding the effectiveness of sirolimus, including Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores, physician's global assessment (PhGA) scores, and proportion of patients with SLEDAI-2K reduction of ≥4 and PhGA increase of <0.3, were equivalent to those of tacrolimus at all follow-up timepoints (all p≥0.05). Greater improvements in complement levels were observed in the sirolimus group at 3 and 6 months. Higher percentages of patients with prednisone doses ≤7.5 mg/day were observed in the sirolimus group at all timepoints. Seventeen adverse events in the sirolimus group were recorded. None was severe or led to drug discontinuation.

CONCLUSIONS

Overall, sirolimus was as effective as tacrolimus in the treatment of SLE. Sirolimus had better effects on serological improvement and glucocorticoid tapering. Sirolimus was well tolerated in patients with SLE.

Plasmacytoid dendritic cell activation is dependent on coordinated expression of distinct amino acid transporters

Human plasmacytoid dendritic cells (pDCs) are interleukin-3 (IL-3)-dependent cells implicated in autoimmunity, but the role of IL-3 in pDC biology is poorly understood. We found that IL-3-induced Janus kinase 2-dependent expression of SLC7A5 and SLC3A2, which comprise the large neutral amino acid transporter, was required for mammalian target of rapamycin complex 1 (mTORC1) nutrient sensor activation in response to toll-like receptor agonists. mTORC1 facilitated increased anabolic activity resulting in type I interferon, tumor necrosis factor, and chemokine production and the expression of the cystine transporter SLC7A11. Loss of function of these amino acid transporters synergistically blocked cytokine production by pDCs. Comparison of in vitro-activated pDCs with those from lupus nephritis lesions identified not only SLC7A5, SLC3A2, and SLC7A11 but also ectonucleotide pyrophosphatase-phosphodiesterase 2 (ENPP2) as components of a shared transcriptional signature, and ENPP2 inhibition also blocked cytokine production. Our data identify additional therapeutic targets for autoimmune diseases in which pDCs are implicated.

Sirolimus for patients with connective tissue disease-related refractory thrombocytopenia: a single-arm, open-label clinical trial

OBJECTIVES

Connective tissue disease-related thrombocytopenia (CTD-TP) is a problematic disorder in clinical practice. Because the first-line therapy of glucocorticoid and/or immunosuppressants is not effective for refractory cases, alternative treatment approaches are urgently needed. The present study investigated the efficacy and safety of sirolimus in refractory CTD-TP patients.

METHODS

This single-centre, single-arm, phase II study enrolled 20 refractory CTD-TP patients between September 2017 and September 2018 (registered on ClinicalTrials.gov: NCT03688191). Oral sirolimus administration was dose-adjusted to maintain a therapeutic range of 6-15 ng/ml for 6 months. The primary endpoints were partial and complete remission rates at 6 months.

RESULTS

Twelve (60%) patients achieved the primary end point with a 50% complete remission rate after 6 months. Among the 14 SLE patients, the overall response rate was 71.4%, with a complete remission rate of 64.3%. None of the primary Sjögren's syndrome cases responded to sirolimus. There was no significant difference in baseline clinical characteristics or lymphocyte subpopulations between responders and non-responders. No severe side effect was detected during the study.

CONCLUSION

Sirolimus is an effective and safe treatment option for refractory CTD-TP patients.

TRIAL REGISTRATION

https://clinicaltrials.gov, NCT03688191.

Therapeutic perspectives on the metabolism of lymphocytes in patients with rheumatoid arthritis and systemic lupus erythematosus

INTRODUCTION

The activation of autoreactive T- and B-cells and production of autoantibodies by B cells are involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Recently, the concept of 'immunometabolism' has attracted significant attention. Immune cells produce large amounts of energy in the form of ATP and biosynthesize biological components such as nucleic acids and lipids via metabolic reprogramming to activate, differentiate, and exert their functions.

AREAS COVERED

While the mechanisms underlying the metabolism of CD4⁺ T cells in SLE have been extensively studied, the metabolic changes underlying B cell activation, differentiation, and function remain unclear. Drugs targeting mTOR and AMPK, such as sirolimus, rapamycin, and metformin, have shown some efficacy and tolerability in clinical trials on patients with SLE, but have not led to breakthroughs. In this review, we summarize the current knowledge on the immunometabolic mechanisms involved in SLE and RA and discuss the potential novel therapeutic drugs.

EXPERT OPINION

The intensity of activation of different immune cells and their metabolic kinetics vary in different autoimmune diseases; thus, understanding the disease- and cell-specific metabolic mechanisms may help in the development of clinically effective immunometabolism-targeting drugs.

T Cells in Systemic Lupus Erythematosus

T-cell dysregulation has been implicated in the loss of tolerance and overactivation of B cells in systemic lupus erythematosus (SLE). Recent studies have identified T-cell subsets and genetic, epigenetic, and environmental factors that contribute to pathogenic T-cell differentiation, as well as disease pathogenesis and clinical phenotypes in SLE. Many therapeutics targeting T-cell pathways are under development, and although many have not progressed in clinical trials, the recent approval of the calcineurin inhibitor voclosporin is encouraging. Further study of T-cell subsets and biomarkers of T-cell action may pave the way for specific targeting of pathogenic T-cell populations in SLE.

Amino Acid Metabolism in Lupus

T cell metabolism is central to cell proliferation, survival, differentiation, and aberrations have been linked to the pathophysiology of systemic autoimmune diseases. Besides glycolysis and fatty acid oxidation/synthesis, amino acid metabolism is also crucial in T cell metabolism. It appears that each T cell subset favors a unique metabolic process and that metabolic reprogramming changes cell fate. Here, we review the mechanisms whereby amino acid transport and metabolism affects T cell activation, differentiation and function in T cells in the prototype systemic autoimmune disease systemic lupus erythematosus. New insights in amino acid handling by T cells should guide approaches to correct T cell abnormalities and disease pathology.

Autophagy Activation by Resveratrol Reduces Severity of Experimental Rheumatoid Arthritis

SCOPE

Previous work reported that dietary supplementation with resveratrol lowers synovial hyperplasia, inflammatory and oxidative damage in an antigen-induced arthritis (AIA) model. Here, it is investigated whether resveratrol can regulate the abnormal synovial proliferation by inducing autophagy and controlling the associated inflammatory response.

METHODS AND RESULTS

Animals treated with resveratrol 8 weeks before AIA induction show the highest significant signal for microtubule-associated protein 1 light chain 3 by confocal microscopy. Besides, resveratrol significantly reduces p62 expression, but it does not increase the signal of beclin-1. Also, active caspase-3 expression, as well as poly(ADP-ribose) polymerase, is upregulated in the AIA group, and is significantly reduced in resveratrol-treated AIA group. Resveratrol also mitigates angiopoietin-1 and vascular endothelial growth factor signals. Finally, resveratrol significantly reduces the serum levels of IL-1β, C reactive protein, and prostaglandin E2, as well as nuclear factor κB synovial tissue expression, which shows a significant correlation with p62 expression.

CONCLUSION

Dietary supplementation with resveratrol induces the noncanonical autophagy pathway and limits the cross-talk with inflammation, which in consequence modulates the synovial hyperplasia. Preventive strategies that incorporate dietary intervention with resveratrol may offer a potential therapeutic alternative to drugs to influence the risk of rheumatoid arthritis and influence its course.

Immunometabolic Pathways and Its Therapeutic Implication in Autoimmune Diseases

Autoimmune diseases (AIDs) are characterized with aberrant immune responses and their respective signaling pathways controlling cell differentiation, death, and survival. Cell metabolism is also an indispensable biochemical process that provides the very fundamental energy and materials. Accumulating evidences implicate that metabolism pathways have critical roles in determining the function of different immune subsets. Mechanisms of how immunometabolism participate in the pathogenesis of AIDs were also under intensive exploration. Here, in this review, we summarize the metabolic features of immune cells in AIDs and also the individual function of immunometabolism pathways, including glucose metabolism and tricarboxylic acid (TCA) cycle, in the setting of AIDs, mainly focusing on the potential targets for intervention. We also review studies that explore the intervention strategies targeting key molecules of metabolic pathways, such as mammalian target of rapamycin (mTOR), AMP-activated protein kinase (AMPK), and hypoxia-inducible factor 1a (HIF1a), in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). The highlight of this review is to provide a comprehensive summary of the status quo of immunometabolism studies in AIDs and the potential translatable drug targets.

Immunometabolism in the pathogenesis of systemic lupus erythematosus: an update

PURPOSE OF REVIEW

To provide an update on state-of-the-art evidence on the role of immunometabolism reprogramming in the pathogenesis of systemic lupus erythematosus (SLE).

RECENT FINDINGS

Mitochondrial dysfunction and enhanced oxidative stress, along with specific defects in other metabolic pathways, can promote dysregulation of innate and adaptive immune responses in SLE. These abnormalities appear to be driven by genetic and epigenetic factors, modulated by stochastic events. In addition to extensive descriptions of abnormalities in immunometabolism of lupus lymphocytes, recent studies support the critical role of dysregulation of metabolic pathways in innate immune cells including neutrophils, macrophages and dendritic cells, in SLE pathogenesis. Recent abnormalities described in lipid metabolism have been associated with SLE disease activity and related damage. Promising therapeutic strategies that target these metabolic abnormalities have recently been described in SLE.

SUMMARY

Fundamental new insights regarding the role of mitochondrial dysfunction in innate immune dysregulation in SLE pathogenesis have recently emerged. Defects in specific molecular pathways pertinent to immunometabolism in SLE have been described. New insights in translational medicine and promising therapeutic targets have been proposed based on these recent findings.

Clinical efficacy and safety of sirolimus in systemic lupus erythematosus: a real-world study and meta-analysis

Objective:

To provide real-world data and summarize current clinical evidence on the efficacy and safety of sirolimus in active systemic lupus erythematosus (SLE) patients.

Methods:

This was a prospective real-world clinical study. Included SLE patients should have Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) ⩾ 2. They were treated with sirolimus and followed up regularly. The SLEDAI-2K, Physician Global Assessment (PGA), serological activity indices, and remission of organ manifestations were evaluated. We also performed a meta-analysis to integrate current evidence of sirolimus in SLE.

Results:

A total of 49 patients were included in the final analysis. After treatment, the SLEDAI-2K (6.2 ± 3.1 versus 4.0 ± 3.4, p = 0.001) decreased significantly, and the prednisone dosage was tapered successfully (9.9 ± 8.8 mg/day versus 5.9 ± 4.0 mg/day, p = 0.002). Serological activity indices also improved [complement 3 (C3): 0.690 ± 0.209 g/l versus 0.884 ± 0.219 g/l, p < 0.001; complement 4: 0.105 ± 0.059 g/l versus 0.141 ± 0.069 g/l, p < 0.001; anti-dsDNA antibody, 200 ± 178 IU/ml versus 156 ± 163 IU/ml, p = 0.022]. The remission proportions of arthritis, skin rash, and thrombocytopenia were 100%, 88.8%, and 46.2%, respectively. A total of 41.2% of lupus nephritis (LN) patients achieved renal remission, but the average 24-h urine protein level was not significantly changed. Meta-analysis enrolled five studies with 149 patients included, and revealed similar results regarding the changes of SLEDAI-2K [−3.5 (−5.0, −2.1)], C3 [0.224 (0.136, 0.311) g/l] and daily dosage of prednisone [−12.7 (−19.9, −5.6) mg/day].

Conclusion:

Sirolimus might be effective and tolerated in SLE. The role of sirolimus in LN requires further study.

Systemic Lupus Erythematosus (SLE) Therapy: The Old and the New

Despite recent improvements in the treatment of systemic lupus erythematosus (SLE), disease activity, comorbidities and drug toxicity significantly contribute to the risk of progressive irreversible damage accrual and increased mortality in patients with this chronic disease. Moreover, even lupus patients in remission often report residual symptoms, such as fatigue, which have a considerable impact on their health-related quality of life. In recent decades, SLE treatment has moved from the use of hydroxychloroquine, systemic glucocorticosteroids and conventional immunosuppressive drugs to biologic agents, of which belimumab is the first and only biologic agent approved for the treatment for SLE to date. Novel therapies targeting interferons, cytokines and their receptors, intracellular signals, plasma cells, T lymphocytes and co-stimulatory molecules are being evaluated. In the context of a holistic approach, growing evidence is emerging of the importance of correct lifestyle habits in the management of lupus manifestations and comorbidities. The aim of this paper is to provide an overview of current pharmacological and non-pharmacological treatment options and emerging therapies in SLE.

Systemic lupus erythematosus: an expert insight into emerging therapy agents in preclinical and early clinical development

INTRODUCTION

Systemic lupus erythematosus (SLE) is a chronic disease that is potentially fatal. There is no cure for SLE and the medications used are associated with toxic side effects. In the era of revolutionary emerging novel biologic agents, the design and investigation of targeted therapy for these patients is necessary. Novel therapies under investigation in phase II-III clinical trials showed promising results. Therapies can target various pathways involved in SLE including cytokines, signal transduction inhibitors, B-cell depletion and interference with co-stimulation. Of interest is the proof of concept of sequential therapy.

AREAS COVERED

We performed an extensive literature search via PubMed, Medline, Elsevier Science and Springer Link databases between the years 2014-2020 using the following terms: SLE, novel treatments. We have reviewed 232 articles and selected those articles that (i) focus on phase II-III emerging therapies and (ii) offer new findings from existing therapies, which reveal breakthrough concepts in SLE treatment.

EXPERT OPINION

It is still difficult to crack the puzzle of a successful SLE treatment approach. New strategies with potential may encompass the targeting of more than one protein. Another way forward is to identify each SLE patient and personalize therapy by clinical manifestations, disease activity, serology and activated protein.

Mechanisms and Functions of Mitophagy and Potential Roles in Renal Disease

Mitophagy is an evolutionarily conserved process to selectively remove damaged or unnecessary mitochondria via the autophagic machinery. In this review, we focus on recent advances in the molecular mechanisms of mitophagy and how mitophagy contributes to cellular homeostasis in physiological and pathological contexts. We also briefly review and discuss the crosstalk between mitophagy and renal disease, highlighting its modulation as a potentially effective therapeutic strategy to treat kidney diseases such as acute kidney injury (AKI), diabetic kidney disease (DKD), and lupus nephritis (LN).

Efficacy and safety of sirolimus in patients with systemic lupus erythematosus: A systematic review and meta-analysis

BACKGROUND

Emerging evidence suggested a potential therapeutic role of targeting mTOR in the treatment of SLE. But most studies were observational studies with limited sample size or case reports.

OBJECTIVE

To evaluate the efficacy and safety of sirolimus in treatment of SLE by systematic review and meta-analysis.

METHODS

Systematic searches of Medline/PubMed, EMBASE, the Cochrane library and Scopus were performed. Original case reports, case series, observational studies and clinical trials reporting the efficacy or safety data on SLE patients treated with sirolimus were included. A random-effects meta-analysis was performed to calculate the pooled efficacy, when possible.

RESULTS

A total of 9 studies comprising 145 patients were identified. The exposure of sirolimus was 245.8 patient-years, with 1-3 mg/day adopted in majority studies. In 111 clinical active patients, the pooled decrease of SLEDAI, BILAG and prednisone dosage was 4.85 (95% CI 3.44-6.25), 1.98 (95% CI 0.23-3.74) and 13.17 mg/day (95% CI 0.71-25.63) respectively. 23 patients initiating sirolimus for active SLE yielded remission in 17 (73.9%) patients. In 22 quiescent lupus nephritis patients, 21 (95.5%) patients sustained remission. Hematological, mucocutaneous abnormalities and dyslipidemia were the most common adverse events. Early cessation due to side effects was reported in 9.28% (13/140) patients, most of the side effects were mild and recovered quickly after cessation.

CONCLUSIONS

Summary of the available datasets indicated sirolimus was promising and well-tolerated in the treatment of SLE. Further randomized controlled trials evaluating the potential benefits and risk of sirolimus in SLE are warranted.

"High Treg" Inflammations Promote (Most) Non-Hematologic Cancers While "Low Treg" Inflammations Promote Lymphoid Cancers

In an earlier publication, a binary classification of chronic diseases has been proposed. Chronic diseases were classified as “high Treg” or “low Treg” diseases depending on whether the pro-inflammatory or the anti-inflammatory arms of the immune response are deficient. The present work uses this model to analyze the interplay between cancer and the immune system, based on published literature. The work leans upon the etiology of alcohol and tobacco-related malignancies. The main conclusions are: triggers of specific “high Treg” immune reaction promote most non-hematologic cancers, whereas triggers of “low Treg” immune reaction promote lymphomas. The opposite is also true: triggers of specific “high Treg” immune reaction suppress lymphoma, whereas triggers of “low Treg” immune reaction suppress non-hematologic cancers. Both lymphoma and autoimmune diseases are “low Treg” conditions. For this reason, both are promoted by the same panel of “low Treg” bacteria and parasites and are inhibited by “high Treg” triggers. For example, alcohol consumption, a “high Treg” trigger, protects against lymphoma and autoimmune hypothyroidism. In addition, the same immune-modulatory drugs are effective in the treatment of both lymphoma and autoimmune diseases. Like other cancers, lymphoma transforms from a “low Treg” type at early stage of the disease into a “high Treg” type at advanced stages. However, lymphoma is distinguished from most other cancers by the length of time it dwells at an indolent “low Treg” state (many years) before lymphoma cells sensitivity to transforming growth factor-beta is impaired. This impairment stimulates the switch from “low Treg” into “high Treg” response and results in immune escape. The application of this analysis to the pharmacological activity of checkpoint inhibitors forecasts that checkpoint inhibitors would not be effective in low-grade, indolent lymphomas. As of now, checkpoint inhibitors are approved for the treatment of advanced lymphoma only.

mTOR Pathway Expression as Potential Predictive Biomarker in Patients with Advanced Neuroendocrine Tumors Treated with Everolimus

Background. Everolimus (Eve), which is a mammalian target of Rapamicin (mTOR) inhibitor, is part of the therapeutic armamentarium of neuroendocrine tumors (NETs). Currently, there are no validated biomarkers predicting Eve efficacy in NETs. In this study, we explore whether the expression of phosphorilated (p)-mTOR and p70S6-kinase (S6K), a downstream effector of mTOR, correlates with the outcome of patients with NET that were treated with Eve. Methods. Tissue specimens that were derived from NETs treated with Eve at our Institution were examined for the expression levels of p-mTOR and p-S6K by immunohistochemistry. Response rate (RR), progression-free survival (PFS), and overall survival (OS) were analyzed in two groups: p-mTOR/p-S6K positive (group 1) and p-mTOR/p-S6K negative (group 2). Univariate and multivariate Cox regression analysis were performed. Results. Twenty-four patients with advanced NETs that were treated with Eve were included in the analysis. Eight out 24 (33.3%) patients were both p-mTOR and p-S6K positive. A better median PFS and OS in group 1 (18.2 and 39.9 months) as compared to group 2 (13 and 32.4 months) was depicted, with a toxicity profile that was comparable with data literature. Conclusions. Our study suggests that the activation of mTOR pathway can predict better outcomes in patients with NET treated with Eve. However, these results warrant further confirmation in a prospective setting.

Rapamycin Re-Directs Lysosome Network, Stimulates ER-Remodeling, Involving Membrane CD317 and Affecting Exocytosis, in Campylobacter Jejuni-Lysate-Infected U937 Cells

The Gram-negative Campylobacter jejuni is a major cause of foodborne gastroenteritis in humans worldwide. The cytotoxic effects of Campylobacter have been mainly ascribed to the actions of the cytolethal distending toxin (CDT): it is mandatory to put in evidence risk factors for sequela development, such as reactive arthritis (ReA) and Guillain–Barré syndrome (GBS). Several researches are directed to managing symptom severity and the possible onset of sequelae. We found for the first time that rapamycin (RM) is able to largely inhibit the action of C. jejuni lysate CDT in U937 cells, and to partially avoid the activation of specific sub-lethal effects. In fact, we observed that the ability of this drug to redirect lysosomal compartment, stimulate ER-remodeling (highlighted by ER–lysosome and ER–mitochondria contacts), protect mitochondria network, and downregulate CD317/tetherin, is an important component of membrane microdomains. In particular, lysosomes are involved in the process of the reduction of intoxication, until the final step of lysosome exocytosis. Our results indicate that rapamycin confers protection against C. jejuni bacterial lysate insults to myeloid cells.

mTOR Blockade by Rapamycin in Spondyloarthritis: Impact on Inflammation and New Bone Formation in vitro and in vivo

Introduction: Spondyloarthritis (SpA) is characterized by inflammation, articular bone erosions and pathologic new bone formation. Targeting TNFα or IL-17A with current available therapies reduces inflammation in SpA, however, treatment of the bone pathology in SpA remains an unmet clinical need. Activation of the mammalian target Of rapamycin (mTOR) promotes IL-17A expression and osteogenesis. Therefore, the inhibition of mTOR (with rapamycin) could be a promising therapeutic avenue in SpA.

Objectives: To investigate the effect of blocking mTOR on inflammation, bone erosions and new bone formation in SpA.

Methods: Peripheral blood mononuclear cells (PBMCs) from patients with SpA were stimulated with anti-CD3/CD28 in the presence or absence of rapamycin and the resulting cytokine expression was assessed. Fibroblast-like synoviocytes (FLS) from SpA patients were assessed for osteogenic differentiation potential in conditions with TNFα, IL-17A, or TNFα plus IL-17A, in the presence or absence of rapamycin. HLA-B27/Huβ2m transgenic rats were immunized with low dose heat-inactivated Mycobacterium tuberculosis (M. tub), treated with 1.5 mg/kg rapamycin prophylactically or therapeutically and monitored for arthritis and spondylitis. Histology and mRNA analysis were performed after 5 weeks of treatment to assess inflammation and bone pathology.

Results:In vitro TNFα and IL-17A protein production by SpA PBMCs was inhibited in the presence of rapamycin. Rapamycin also inhibited osteogenic differentiation of human SpA FLS. Ex vivo analysis of SpA synovial biopsies indicated activation of the mTOR pathway in the synovial tissue of SpA patients. In vivo, prophylactic treatment of HLA-B27/Huβ2m transgenic rats with rapamycin significantly inhibited the development and severity of inflammation in peripheral joints and spine (arthritis and spondylitis), with histological evidence of reduced bone erosions and new bone formation around peripheral joints. In addition, therapeutic treatment with rapamycin significantly decreased severity of arthritis and spondylitis, with peripheral joint histology showing reduced inflammation, bone erosions and new bone formation. IL-17A mRNA expression was decreased in the metacarpophalangeal joints after rapamycin treatment.

Conclusion: mTOR blockade inhibits IL-17A and TNFα production by PBMCs, and osteogenic differentiation of FLS from patients with SpA in vitro. In the HLA-B27 transgenic rat model of SpA, rapamycin inhibits arthritis and spondylitis development and severity, reduces articular bone erosions, decreases pathologic new bone formation and suppresses IL-17A expression. These results may support efforts to evaluate the efficacy of targeting the mTOR pathway in SpA patients.

Altered Tregs and oxidative stress in pregnancy associated lupus

AIM

SLE is a systemic autoimmune disease generally affecting woman in the reproductive age. It is associated with an altered level of Tregs and oxidative stress while an increase in Tregs, and different antioxidant mechanisms to combat oxidative stress are essential for successful pregnancy. Hence, this study aims to determine the level of CD4⁺ and CD8⁺ Tregs and oxidative stress in pregnant lupus patients.

METHODS

Ten healthy and 10 pregnant lupus volunteers from the North Indian population, within the age group of 20-30 years were enrolled in the study. All the patients were non-smokers, non-alcoholics and were not associated or undergoing therapy for any other disease. They had a SLEDAI of 37.4 ± 7.32 with 5.2 ± 1.93 years of disease duration. Oxidative stress was determined by measuring the enzyme activity of anti-oxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and the level of reduced glutathione and lipids peroxidised, spectrophotometrically. Flowcytometry was performed for immunophenotyping to determine CD8⁺ and CD4⁺ Tregs.

RESULTS

Elevated CD8⁺ Tregs and diminished CD4⁺ Tregs were observed in pregnant lupus patients. Oxidative stress was significantly increased as the activities of anti-oxidant enzymes and level of reduced glutathione was considerably diminished. There was a substantial increase in the amount of lipids peroxidised.

CONCLUSION

Pregnant lupus patients undergo considerable level of oxidative stress in comparison to healthy pregnant woman. The decreased level of CD4⁺ Tregs and an increase in CD8⁺ Tregs might be another important factor responsible for pregnancy associated complications. Hence, lupus leads to alterations in the necessary conditions for a successful pregnancy, which might eventually cause higher mortality, morbidity and associated complications.