DC-Based Immunotherapy Combined with Low-Dose Methotrexate Effective in the Treatment of Advanced CIA in Mice

How to focus on autoantigen-specific lymphocytes: a review on diagnosis and treatment of Sjogren's syndrome

Sjogren's syndrome (SS) is an autoimmune epithelitis characterized by focal lymphocytic infiltration against self-antigens leading to progressive glandular dysfunction, which can develop to multisystem manifestation. The classification criteria for SS emphasizes glandular lymphocyte infiltrates and anti-SSA/SSB seropositivity, which is usually manifested in advanced patients. Therapeutically, apart from symptomatic treatment, treatment of SS is based on glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs with global immunosuppression, but the efficacy of biologic or targeted synthetic therapies is still sparse. Currently, emerging studies focus on autoantigen-specific immunotherapies to treat autoimmune disorders by directly eliminating autoreactive cell subsets and inducing tolerance by increasing the autoreactive regulatory lymphocytes. Herein, we summarize the current state of research on the autoantigen-specific approaches for detecting autoreactive lymphocytes and outline the current autoantigen-specific immunotherapies in other autoimmune disorders and their attempts in treatment of SS. Last, we discuss the potential value of focusing on autoantigen-specific lymphocytes in the early diagnosis, monitoring, and targeted treatment of SS. Potential strategies for targeting autoreactive lymphocytes need to be confirmed in SS.

ABCC1, ABCG2 and FOXP3: Predictive Biomarkers of Toxicity from Methotrexate Treatment in Patients Diagnosed with Moderate-to-Severe Psoriasis

BACKGROUND

Methotrexate (MTX) is one of the most extensively used drugs in the treatment of moderate-to-severe psoriasis (PS). However, it frequently must be suspended owing to the toxicity in certain patients.

OBJECTIVE

To evaluate the influence of ABCC1, ABCG2, and FOXP3 in the development of MTX toxicity in PS.

METHODS

Retrospective cohort study with 101 patients. Five single-nucleotide polymorphisms (SNPs) were genotyped using real-time polymerase chain reaction with TaqMan probes.

RESULTS

Patients carrying ABCC1 rs2238476-AG genotype (AG vs. GG: OR = 8.04; 95% CI = 1.48-46.78; p = 0.015); FOXP3 rs376154-GT and GG genotypes (GT vs. TT/GG: OR = 3.86; 95% CI = 1.17-13.92; p = 0.031) and ABCG2 rs13120400-T allele (T vs. CC: OR = 8.33; 95% CI = 1.24-164.79; p = 0.059) showed a higher risk of developing more than one adverse effect. The toxicity analysis by subtypes showed that the ABCC1 rs2238476-AG genotype (AG vs. GG: OR = 8.10; 95% CI = 1.69-46.63; p = 0.011) and FOXP3 rs376154-GT genotype (OR = 4.11; 95% CI = 1.22-15.30; p = 0.027) were associated with the appearance of asthenia. No association of the other ABCC1 polymorphisms (rs35592 and rs246240) with MTX toxicity was found.

CONCLUSION

ABCC1, ABCG2, and FOXP3 polymorphisms can be considered to be risk biomarkers of toxicities in PS patients treated with MTX.

CXCR4 blockade reduces the severity of murine heart allograft rejection by plasmacytoid dendritic cell-mediated immune regulation

Allograft-specific regulatory T cells (T_reg cells) are crucial for long-term graft acceptance after transplantation. Although adoptive T_reg cell transfer has been proposed, major challenges include graft-specificity and stability. Thus, there is an unmet need for the direct induction of graft-specific T_reg cells. We hypothesized a synergism of the immunotolerogenic effects of rapamycin (mTOR inhibition) and plerixafor (CXCR4 antagonist) for T_reg cell induction. Thus, we performed fully-mismatched heart transplantations and found combination treatment to result in prolonged allograft survival. Moreover, fibrosis and myocyte lesions were reduced. Although less CD3⁺ T cell infiltrated, higher T_reg cell numbers were observed. Noteworthy, this was accompanied by a plerixafor-dependent plasmacytoid dendritic cells-(pDCs)-mobilization. Furthermore, in vivo pDC-depletion abrogated the plerixafor-mediated T_reg cell number increase and reduced allograft survival. Our pharmacological approach allowed to increase T_reg cell numbers due to pDC-mediated immune regulation. Therefore pDCs can be an attractive immunotherapeutic target in addition to plerixafor treatment.

Neutrophils Enable Local and Non-Invasive Liposome Delivery to Inflamed Skeletal Muscle and Ischemic Heart

Uncontrolled inflammation is a major pathological factor underlying a range of diseases including autoimmune conditions, cardiovascular disease, and cancer. Improving localized delivery of immunosuppressive drugs to inflamed tissue in a non-invasive manner offers significant promise to reduce severe side effects caused by systemic administration. Here, a neutrophil-mediated delivery system able to transport drug-loaded nanocarriers to inflamed tissue by exploiting the inherent ability of neutrophils to migrate to inflammatory tissue is reported. This hybrid system (neutrophils loaded with liposomes ex vivo) efficiently migrates in vitro following an inflammatory chemokine gradient. Furthermore, the triggered release of loaded liposomes and reuptake by target macrophages is studied. The migratory behavior of liposome-loaded neutrophils is confirmed in vivo by demonstrating the delivery of drug-loaded liposomes to an inflamed skeletal muscle in mice. A single low-dose injection of the hybrid system locally reduces inflammatory cytokine levels. Biodistribution of liposome-loaded neutrophils in a human-disease-relevant myocardial ischemia reperfusion injury mouse model after i.v. injection confirms the ability of injected neutrophils to carry loaded liposomes to inflammation sites. This strategy shows the potential of nanocarrier-loaded neutrophils as a universal platform to deliver anti-inflammatory drugs to promote tissue regeneration in inflammatory diseases.

Ceria-based nanotheranostic agent for rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that affects 1-2% of the human population worldwide, and effective therapies with targeted delivery for local immune suppression have not been described. We address this problem by developing a novel theranostic nanoparticle for RA and assessed its therapeutic and targeting effects under image-guidance. Methods: Albumin-cerium oxide nanoparticles were synthesized by the biomineralization process and further conjugated with near-infrared, indocyanine green (ICG) dye. Enzymatic-like properties and reactive oxygen species (ROS) scavenging activities, as well as the ability to reprogram macrophages, were determined on a monocyte cell line in culture. The therapeutic effect and systemic targeting potential were evaluated in collagen-induced arthritis (CIA) mouse model using optical/optoacoustic tomographic imaging. Results: Small nanotheranostics with narrow size distribution and high colloidal stability were fabricated and displayed high ROS scavenging and enzymatic-like activity, as well as advanced efficacy in a converting pro-inflammatory macrophage phenotype into anti-inflammatory phenotype. When administrated into affected animals, these nanoparticles accumulated in inflamed joints and revealed a therapeutic effect similar to the gold-standard therapy for RA, methotrexate. Conclusions: The inflammation-targeting, inherent contrast and therapeutic activity of this new albumin-cerium oxide nanoparticle may make it a relevant agent for assessing severity in RA, and other inflammatory diseases, and controlling inflammation with image-guidance. The design of these nanotheranostics will enable potential clinical translation as systemic therapy for RA.

Tolerogenic Dendritic Cells Generated by BAFF Silencing Ameliorate Collagen-Induced Arthritis by Modulating the Th17/Regulatory T Cell Balance

Tolerogenic dendritic cells (tolDCs) have received much attention because of their capacity to restore immune homeostasis. RNA interference techniques have been used in several studies to generate tolDCs by inactivating certain molecules that regulate DC maturation and immunologic function. BAFF is a key B cell survival factor that is not only essential for B cell function but also T cell costimulation, and DCs are the major source of BAFF. In this study, we determined whether BAFF gene silencing in mature DCs could lead to a tolerogenic phenotype as well as the potential therapeutic effect of BAFF-silenced DCs on collagen-induced arthritis (CIA) in mice. Meanwhile, CRISPR/Cas9-mediated BAFF^-/- DC2.4 cells were generated to verify the role of BAFF in DC maturation and functionality. BAFF-silenced DCs and BAFF^-/- DC2.4 cells exhibited an immature phenotype and functional state. Further, the transplantation of BAFF-silenced DCs significantly alleviated CIA severity in mice, which correlated with a reduction in Th17 populations and increased regulatory T cells. In vitro, BAFF-silenced DCs promoted Foxp3 mRNA and IL-10 expression but inhibited ROR-γt mRNA and IL-17A expression in CD4⁺ T cells. Together, BAFF-silenced DCs can alleviate CIA, partly by inducing Foxp3⁺ regulatory T cells and suppressing Th17 subsets. Collectively, BAFF plays an important role in interactions between DCs and T cells, which might be a promising genetic target to generate tolDCs for autoimmune arthritis treatment.

The CD25+/CD4+ T cell ratio and levels of CII, CIX and CXI antibodies in serum may serve as biomarkers of pristane-induced arthritis in rats and Rheumatoid Arthritis in humans

OBJECTIVE

Collagen antibodies in serum are involved in the pathogenesis of Rheumatoid Arthritis (RA). The objective of this study was to identify the subtype of collagen antibodies and T cell subtype distribution in pristane-induced arthritis (PIA) and to clarify their roles in the initiation and maintenance of arthritis.

METHODS

Arthritis was induced in Dark Agouti (DA) rats by injection of pristane. The severity was evaluated by macroscopic and microscopic score systems. The alteration of CD25+/CD4+ T cell ratio in rats was detected by flow cytometry. Collagen type II (CII), CIX, or CXI antibody in serum was determined by ELISA. The levels of Nitric oxide (NO) and tartrate-resistant acid phosphatase (TRAP) were measured by kits.

RESULTS

The serum levels of CII, CIX, CXI antibodies were significantly increased in RA patients while slightly increased in PIA rats. The ratio of CD25+/CD4+ T cells was significantly higher in RA rats than that in the control group. The serum levels of NO and TRAP in PIA rats and RA patients were higher than that in the control groups, which suggested that the activity of osteoclast was increased in RA.

CONCLUSION

The ratio of CD25+/CD4+ T cells plays a pivotal role in the development of PIA. The serum levels of NO and TRAP are inflammatory and osteoclast activity indicators. The serum levels of CII, CIX and CXI antibodies may serve as the clinical diagnostic indicators. These findings are important to our understanding of the pathogenesis of RA, and may provide biomarkers of RA diagnosis and therapeutic targets for the treatment of RA.

Bone erosions in rheumatoid arthritis: recent developments in pathogenesis and therapeutic implications

Bone erosions develop early in the course of rheumatoid arthritis (RA) and deteriorate progressively, causing joint damage and resulting in impaired functional capacity of patients. During the last years, considerable number of studies has increased our understanding of the pathogenetic mechanisms mediating the development of bone erosions in RA. Increased production of RANKL and other cytokines, dysregulation of innate immune mechanisms, autoantibodies specific to RA and alterations of microRNA expression stimulate differentiation and function of osteoclasts, which are responsible for the development of bone erosions. Besides, increased levels of cytokines, overproduction of antagonists of the canonical Wnt signaling pathway and deficient production of bone morphogenetic proteins result in impaired osteoblast differentiation and function, undermining the capacity of bone erosions to repair. Disease-modifying antirheumatic drugs, synthetic or biological, currently used in the treatment of RA, can halt the progression of bone erosions and may even lead to partial repair, although complete repair is unattainable. Targeting pathogenetic mechanisms participating in the erosive process may add to the therapeutic effect of DMARDs and help in the prevention or repair of bone erosions. However, more studies are still needed to confirm whether such therapeutic strategies are effective.

PHARMACOTHERAPY FOR RHEUMATOID ARTHRITIS: NEW STRATEGY, NEW TARGETS

Rheumatoid arthritis (RA) is a chronic immunoinflammatory (autoimmune) disease manifested by progressive joint destruction, systemic inflammation of the internal organs, and a wide range of comorbidities associated with chronic inflammation and frequently with adverse drug reactions. However, despite the major advances in the early diagnosis and treatment of RA, which have led to the radical improvement of prognosis in many patients, the problem of pharmacotherapy for RA is far from being solved. This is determined by a lack of sensitive and specific diagnostic and prognostic biomarkers in the early stage of the disease and, most importantly, by the heterogeneity of immunopathogenesis mechanisms in both at the onset of RA and during its progression, which make the personalization of therapy difficult in the patients. Selective block of inflammatory mediators with innovative medicines is frequently associated with primary inefficiency, secondary drug resistance, the development of generalized immunosuppression, the paradoxical activation of an autoimmune process, and the aggravation of comorbidities. At the same time, it is difficult to search for new RA pharmacotherapy targets since the nature of immunopathological disorders in patients can be substantially different from the inflammatory process that takes place when simulating arthritis in laboratory animals. The paper discusses the novel drugs that are used in rheumatology to treat RA or tested in different phases of preclinical or clinical trials, such as tumor necrosis factor-α inhibitors, interleukin-6 (IL-6), IL-17, anti-B cell therapy, bispecific antibodies, blockers of JAK (and other signaling molecules), bioelectronic vagus nerve activation, dendritic cell-based immunotherapy, and other therapies, as well as approaches to secondary prevention of RA in patients with undifferentiated arthritis and clinically suspect arthralgia, who are at high risk for RA. Decoding the mechanisms underlying the pathogenesis of RA and a chronic inflammatory process as a whole has created preconditions for the design of novel medications for the prevention and treatment of this disease, the introduction of which into clinical practice should lead to a radical improvement of prognosis in this disease.

Targeting of tolerogenic dendritic cells towards heat-shock proteins: a novel therapeutic strategy for autoimmune diseases?

Tolerogenic dendritic cells (tolDCs) are a promising therapeutic tool to restore immune tolerance in autoimmune diseases. The rationale of using tolDCs is that they can specifically target the pathogenic T-cell response while leaving other, protective, T-cell responses intact. Several ways of generating therapeutic tolDCs have been described, but whether these tolDCs should be loaded with autoantigen(s), and if so, with which autoantigen(s), remains unclear. Autoimmune diseases, such as rheumatoid arthritis, are not commonly defined by a single, universal, autoantigen. A possible solution is to use surrogate autoantigens for loading of tolDCs. We propose that heat-shock proteins may be a relevant surrogate antigen, as they are evolutionarily conserved between species, ubiquitously expressed in inflamed tissues and have been shown to induce regulatory T cells, ameliorating disease in various arthritis mouse models. In this review, we provide an overview on how immune tolerance may be restored by tolDCs, the problem of selecting relevant autoantigens for loading of tolDCs, and why heat-shock proteins could be used as surrogate autoantigens.

Future therapeutic targets in rheumatoid arthritis?

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint inflammation. Without adequate treatment, patients with RA will develop joint deformity and progressive functional impairment. With the implementation of treat-to-target strategies and availability of biologic therapies, the outcomes for patients with RA have significantly improved. However, the unmet need in the treatment of RA remains high as some patients do not respond sufficiently to the currently available agents, remission is not always achieved and refractory disease is not uncommon. With better understanding of the pathophysiology of RA, new therapeutic approaches are emerging. Apart from more selective Janus kinase inhibition, there is a great interest in the granulocyte macrophage-colony stimulating factor pathway, Bruton's tyrosine kinase pathway, phosphoinositide-3-kinase pathway, neural stimulation and dendritic cell-based therapeutics. In this review, we will discuss the therapeutic potential of these novel approaches.

Systemic Administration of Proteoglycan Protects BALB/c Retired Breeder Mice from Experimental Arthritis

This study was undertaken to evaluate the prophylactic potential of proteoglycan (PG) administration in experimental arthritis. Female BALB/c retired breeder mice received two (2xPG50 and 2xPG100 groups) or three (3xPG50 group) intraperitoneal doses of bovine PG (50 μg or 100 μg) every three days. A week later the animals were submitted to arthritis induction by immunization with three i.p. doses of bovine PG associated with dimethyldioctadecylammonium bromide adjuvant at intervals of 21 days. Disease severity was daily assessed after the third dose by score evaluation. The 3xPG50 group showed significant reduction in prevalence and clinical scores. This protective effect was associated with lower production of IFN-γ and IL-17 and increased production of IL-5 and IL-10 by spleen cells restimulated in vitro with PG. Even though previous PG administration restrained dendritic cells maturation this procedure did not alter the frequency of regulatory Foxp3⁺ T cells. Lower TNF-α and IL-6 levels and higher expression of ROR-γ and GATA-3 were detected in the paws of protected animals. A delayed-type hypersensitivity reaction confirmed specific tolerance induction. Taken together, these results indicate that previous PG inoculation determines a specific tolerogenic effect that is able to decrease severity of subsequently induced arthritis.

Dendritic Cell-based Immunotherapy for Rheumatoid Arthritis: from Bench to Bedside

Dendritic cells (DCs) are professional antigen presenting cells, and play an important role in the induction of antigen-specific adaptive immunity. However, some DC populations are involved in immune regulation and immune tolerance. These DC populations are believed to take part in the control of immune exaggeration and immune disorder, and maintain immune homeostasis in the body. Tolerogenic DCs (tolDCs) can be generated in vitro by genetic or pharmacological modification or by controlling the maturation stages of cytokine-derived DCs. These tolDCs have been investigated for the treatment of rheumatoid arthritis (RA) in experimental animal models. In the last decade, several in vitro and in vivo approaches have been translated into clinical trials. As of 2015, three tolDC trials for RA are on the list of ClinicalTrial.gov (www.clinicaltrials.gov). Other trials for RA are in progress and will be listed soon. In this review, we discuss the evolution of tolDC-based immunotherapy for RA and its limitations and future prospects.