New therapies for systemic lupus erythematosus: cellular targets

Molecular mechanism of celastrol in the treatment of systemic lupus erythematosus based on network pharmacology and molecular docking technology

BACKGROUND

Network pharmacology uses bioinformatics to broaden our understanding of drug actions and thereby advance drug discovery. Here we apply network pharmacology to generate testable hypotheses about the multi-target mechanism of celastrol against systemic lupus erythematosus (SLE).

METHODS

We reconstructed drug-target pathways and networks to predict the likely protein targets of celastrol and the main interactions between those targets and the drug. Then we validated our predictions of candidate targets by performing docking studies with celastrol.

RESULTS

The results suggest that celastrol acts against SLE by regulating the function of several signaling proteins, such as interleukin 10, tumor necrosis factor, and matrix metalloprotein 9, which regulate signaling pathways involving mitogen-activated protein kinase and tumor necrosis factor as well as apoptosis pathways. Celastrol is predicted to affect networks involved mainly in cytokine activity, cytokine receptor binding, receptor ligand activity, receptor regulator activity, and cofactor binding. Molecular docking analysis showed that hydrogen bonding and π-π stacking were the main forms of interaction.

CONCLUSIONS

This network pharmacology strategy may be useful for discovery of multi-target drugs against complex diseases, specifically, it provides protein targets associated with SLE that may be further tested for therapeutic potential by celastrol.

Rituximab induces a rapid and sustained remission in Colombian patients with severe and refractory systemic lupus erythematosus

Despite aggressive treatment for systemic lupus erythematosus (SLE) with high-dose glucocorticoids and immunosuppressive agents, a significant proportion of patients persist with activity or relapse. Although the results from randomized studies showed no beneficial effects of rituximab (RTX) in SLE, this treatment has proven promising results in open label trials including patients with severe and refractory disease. We report a prospective cohort of 42 Colombian patients with severe and refractory SLE treated with RTX after failure response to glucocorticoids and, at least, another immunosuppressive drug. We observed a reduction in steroid requirement [47.4 mg/day at 24 months (p < 0.001)]. Since the first three-month follow-up, 28% and 36% of the patients fulfilled criteria of complete or partial remission according to proteinuria, and 12.5% and 33% according to creatinine clearance, respectively. These response criteria remained at 12 months. Both neuropsychiatric and hematological sub-groups had a favorable clinical response. The median reinfusion-free survival time was 44 months (95% confidence interval: 10.1-50.1) and 80% of the patients did not require RTX reinfusion. Eleven adverse events were reported in 28 subjects. Most of these occurred during the first three-month follow-up, time during which patients were exposed to high-dose glucocorticoids.

Cardiovascular disease complications in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly variable autoimmune disease characterized by aberrant host-immune responses and chronic inflammation. Recently, a strong association between cardiovascular (CV) disease and SLE has emerged. Thus, low serum, high-density lipoprotein strongly correlated with elevated erythrocyte sedimentation rate, IL-6, TNF-alpha and the SLE disease activity index after adjusting for age, gender, race, BMI, insulin sensitivity and any concurrent drug use. In SLE, CV disease is characterized by increased VEGF, which may alter vascular hemostasis and promote neoangiogenesis. Increased low-density lipoprotein-cholesterol and proinflammatory high-density lipoprotein-cholesterol uptake by monocytes together with enhanced low-density lipoprotein-cholesterol oxidation results in the deposition of altered cholesterol forms into the vascular wall. This contributes to precocious and accelerated development of coronary artery plaques. Cholesterol-reducing drugs should be considered in the standard of care of SLE patients, especially in those with an unfavorable CV disease risk profile, which could reduce the probability of atherosclerosis progressing to CV disease or stroke in these patients.

[Efficacy of rituximab versus cyclophosphamide in lupus patients with severe manifestations. A randomized and multicenter study]

There are no controlled studies that compare the efficacy of RTX with standard treatment, such as cyclophosphamide, in patients with systemic lupus erythematosus (SLE).

OBJECTIVE

The objective of this study was to compare the efficacy of rituximab to that of cyclophosphamide in patients with severe manifestations of SLE.

MATERIALS AND METHOD

This is a multicenter, randomized open and controlled trial in adults with a diagnosis of active SLE. Patients were randomized into two groups; group 1: treated with RTX and group 2: cyclophosphamide pulses with the same steroid scheme. We registered MEX-SLEDAI, steroid requirements and adverse events for 12 months. Descriptive and comparative statistic analysis was performed.

RESULTS

19 patients were included, 17 females, mean age 35.7±12.1 years and duration of disease 5.6 years (range 0.35 to 30.8 years). There were no differences at baseline regarding gender, age, duration of disease, previous treatments or disease activity between both groups. MEX-SLEDAI was reduced from 12 to 3 in group 1 and from 9 to 2 in group 2 (p=0.80). Nevertheless, patients treated with RTX had a faster improvement. There was no difference in the cumulative steroid dose. Both groups had significant reduction in antinuclear antibody levels and similar increase in C3 levels. Adverse events were similar in both groups.

CONCLUSION

This comparative clinical study in patients with SLE shows that rituximab can be as useful as cyclophosphamide for severe manifestations, maybe showing a faster response. Adverse events were no different. Rituximab should be considered as an adequate alternative for this group of patients.

An exploratory dose-escalating study investigating the safety, tolerability, pharmacokinetics and pharmacodynamics of intravenous atacicept in patients with systemic lupus erythematosus

Atacicept, a recombinant fusion protein containing the extracellular, ligand-binding portion of the transmembrane activator and calcium modulator and cyclophilin-ligand interactor receptor, and the Fc portion of human immunoglobulin (Ig) G, is designed to block the activity of B-lymphocyte stimulator and a proliferation-inducing ligand, and may have utility as a treatment for B-cellmediated diseases, such as systemic lupus erythematosus (SLE). This Phase Ib study investigated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of intravenous (i.v.) atacicept in patients with mild-to-moderate SLE. Patients (n = 24) were randomised (5:1) to receive atacicept (single dose: 3, 9 or 18 mg/kg; or multiple dose: 2 × 9 mg/kg) or matching placebo. Patients were followed for 6 weeks after dosing (9 weeks in the 2 × 9 mg/kg cohort). Local tolerability of atacicept was comparable with that of placebo, with only mild injection-site reactions reported with atacicept. Atacicept i.v. was generally well tolerated, both systemically and locally, in patients with mild-to-moderate SLE. Atacicept displayed non-linear PK, which was predictable across doses and between single and repeat doses. The biological activity of atacicept was demonstrated by its marked effect in reducing B-cells and Ig levels in patients with SLE. This supports the utility of this therapeutic approach in the treatment of autoimmune diseases, such as SLE.

Systemic Lupus Erythematosus: A Therapeutic Update

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with variable clinical manifestations that is characterized by flares and periods of relative quiescence. The disease occurs approximately 10 times more frequently in women and is more prevalent among certain ethnic groups. The etiology is complex and dependent upon an interaction of genetic, hormonal, and environmental factors. Corticosteroids and immunosuppressive agents have transformed the outlook for patients with lupus. Unfortunately, the increased lifespan unmasked an accelerated process of atherosclerosis and cardiovascular disease. Early mortality is usually attributable to active lupus, but deaths late in the disease process are often secondary to thrombotic events. Advancements in the understanding of molecular and cellular mechanisms involved in the pathogenesis have resulted in development of novel therapies. Immunomodulatory drugs developed for other diseases are being investigated for use in specific manifestations of lupus. Individualization of treatment and lifelong monitoring are required in most patients.

Successful treatment of amegakaryocytic thrombocytopenia with anti-CD20 antibody (rituximab) in a patient with systemic lupus erythematosus

Amegakaryocytic thrombocytopenia is an extremely rare disorder in systemic lupus erythematosus, and its mechanism and treatment are still largely unknown. We describe a 42-year-old woman with systemic lupus erythematosus who presented various clinical manifestations of life-threatening amegakaryocytic thrombocytopenia (10,000 platelets/mm3 with a marked decrease of megakaryocytes in the bone marrow), proteinuria, psychosis, refractory chylothorax, ascites, and type II diabetes caused by the anti-insulin receptor autoantibody. She was initially treated with prednisolone (25-50 mg/day) and cyclosporine A (200 mg/day) without any improvement in severe thrombocytopenia. However, her clinical symptoms, including platelet counts, dramatically improved, with a concurrent decrease in the anti-c-Mpl antibody, an autoantibody against the thrombopoietin receptor, after a subsequent treatment with rituximab (375 mg/m2 intravenously, weekly, for two consecutive weeks). Our case suggested that amegakaryocytic thrombocytopenia in patients with systemic lupus erythematosus might be mediated by the anti-c-Mpl antibody and could be treated with rituximab through elimination of pathogenic B cells producing autoimmune antibodies.

An update on selected connective tissue diseases in adolescents

PURPOSE OF REVIEW

This review highlights recent advances in our current understanding of several autoimmune disorders that affect adolescents. Systemic lupus erythematosus, juvenile dermatomyositis, and juvenile localized scleroderma stand out among the connective tissue diseases for their multiorgan involvement, significant potential morbidity, and the challenges of chronic treatment.

RECENT FINDINGS

A better understanding of the pathogenesis of these diseases and new insights into the relationship between the immune dysregulation and clinical features has allowed for the development of novel therapies that are more efficacious and targeted than traditional therapies.

SUMMARY

This article provides an update of the recent literature, highlighting advances that the general pediatrician should know in the care of adolescents with these diseases.

Dendritic cells and cytokines in human inflammatory and autoimmune diseases

Dendritic cells (DCs) produce cytokines and are susceptible to cytokine-mediated activation. Thus, interaction of resting immature DCs with TLR ligands, for example nucleic acids, or with microbes leads to a cascade of pro-inflammatory cytokines and skewing of T cell responses. Conversely, several cytokines are able to trigger DC activation (maturation) via autocrine, for example TNF and plasmacytoid DCs, and paracrine, for example type I IFN and myeloid DCs, pathways. By controlling DC activation, cytokines regulate immune homeostasis and the balance between tolerance and immunity. The increased production and/or bioavailability of cytokines and associated alterations in DC homeostasis have been implicated in various human inflammatory and autoimmune diseases. Targeting these cytokines with biological agents as already is the case with TNF and IL-1 represents a success of immunology and the coming years will expand the range of cytokines as therapeutic targets in autoinflammatory and autoimmune pathology.

Depletion of B cells in murine lupus: efficacy and resistance

In mice, genetic deletion of B cells strongly suppresses systemic autoimmunity, providing a rationale for depleting B cells to treat autoimmunity. In fact, B cell depletion with rituximab is approved for rheumatoid arthritis patients, and clinical trials are underway for systemic lupus erythematosus. Yet, basic questions concerning mechanism, pathologic effect, and extent of B cell depletion cannot be easily studied in humans. To better understand how B cell depletion affects autoimmunity, we have generated a transgenic mouse expressing human CD20 on B cells in an autoimmune-prone MRL/MpJ-Fas(lpr) (MRL/lpr) background. Using high doses of a murine anti-human CD20 mAb, we were able to achieve significant depletion of B cells, which in turn markedly ameliorated clinical and histologic disease as well as antinuclear Ab and serum autoantibody levels. However, we also found that B cells were quite refractory to depletion in autoimmune-prone strains compared with non-autoimmune-prone strains. This was true with multiple anti-CD20 Abs, including a new anti-mouse CD20 Ab, and in several different autoimmune-prone strains. Thus, whereas successful B cell depletion is a promising therapy for lupus, at least some patients might be resistant to the therapy as a byproduct of the autoimmune condition itself.

Vaccine responses in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that is associated with immunologic alterations in T cells and B cells. Moreover, many of the agents used in RA patients are potentially immunosuppressive. Thus, the underlying disease and treatment may both increase the susceptibility to infections and decrease vaccine responses. With the growing use of aggressive therapies for RA, including anti-tumor necrosis factor agents and newer biologic therapies such as rituximab and abatacept, an increasing concern will be that patients may not respond to conventional vaccination. Further prospective studies on response to vaccination are needed to answer this important public health question. Nevertheless, it is already clear that vaccination does induce response in many patients. Unfortunately, vaccination is underutilized in RA patients and needs to be aggressively promoted.

LJP-394 (abetimus sodium) in the treatment of systemic lupus erythematosus

Renal disease is one of the most severe aspects of systemic lupus erythematosus (SLE), potentially leading to irreversible kidney failure. The standard of care for severe lupus nephritis involves the use of high-dose corticosteroids, cyclophosphamide and other immunosuppressive drugs. Although these drugs are effective in controlling disease activity in the majority of patients, up to 25% of patients treated with cyclophosphamide-based protocols develop renal insufficiency and end-stage renal disease, and treatment discontinuation is associated with the occurrence of flares. Furthermore, these therapies are associated with a high incidence of short- and long-term side effects. LJP-394 (abetimus sodium) is an investigational agent specifically designed to decrease anti-dsDNA antibody levels, and it is under development for the prevention of nephritic flares in patients with SLE since the early 1990s. The drug has been evaluated in 13 clinical trials that evaluated > 800 patients with SLE, over a 10-year time span. It is likely that LJP-394 might have a role in the prevention of renal flares in SLE patients, and if the initial data is confirmed in an ongoing trial, this drug could represent either a substitute for immunosuppressive drugs or could allow a reduction of their dose, thereby reducing the risks of short- and long-term side effects. This paper reviews the principal aspects of chemistry, pharmacokinetics, efficacy and safety of LJP-394, and analyses studies on animal models and clinical studies conducted in the last few years.

Update on Connective Tissue Diseases in Dermatology

Recent advances in understanding the pathogenesis of autoimmune diseases, including lupus erythematosus, dermatomyositis, and scleroderma, have allowed for reorganization of the classification of these disorders. With these novel stratifications, early identification of rheumatic skin diseases with systemic implications and consistency in designing and executing therapeutic trials will be enhanced. This review will provide a compilation of updates on epidemiology, pathology, evaluation, and classification with a predominant focus on therapeutics, reflecting the growth is this area.