The role of dendritic cells in autoimmunity

Advancements in rheumatoid arthritis therapy: a journey from conventional therapy to precision medicine via nanoparticles targeting immune cells

Rheumatoid arthritis (RA) is a progressive autoimmune disease that mainly affects the inner lining of the synovial joints and leads to chronic inflammation. While RA is not known as lethal, recent research indicates that it may be a silent killer because of its strong association with an increased risk of chronic lung and heart diseases. Patients develop these systemic consequences due to the regular uptake of heavy drugs such as disease-modifying antirheumatic medications (DMARDs), glucocorticoids (GCs), nonsteroidal anti-inflammatory medicines (NSAIDs), etc. Nevertheless, a number of these medications have off-target effects, which might cause adverse toxicity, and have started to become resistant in patients as well. Therefore, alternative and promising therapeutic techniques must be explored and adopted, such as post-translational modification inhibitors (like protein arginine deiminase inhibitors), RNA interference by siRNA, epigenetic drugs, peptide therapy, etc., specifically in macrophages, neutrophils, Treg cells and dendritic cells (DCs). As the target cells are specific, ensuring targeted delivery is also equally important, which can be achieved with the advent of nanotechnology. Furthermore, these nanocarriers have fewer off-site side effects, enable drug combinations, and allow for lower drug dosages. Among the nanoparticles that can be used for targeting, there are both inorganic and organic nanomaterials such as solid-lipid nanoparticles, liposomes, hydrogels, dendrimers, and biomimetics that have been discussed. This review highlights contemporary therapy options targeting macrophages, neutrophils, Treg cells, and DCs and explores the application of diverse nanotechnological techniques to enhance precision RA therapies.

Effect of acetylcholinesterase inhibition on immune cells in the murine intestinal mucosa

The gastrointestinal tract (GI) is the largest immune organ whose function is controlled by a complex network of neurons from the enteric nervous system (ENS) as well as the sympathetic and parasympathetic system. Evolving evidence indicates that cross-communication between gut-innervating neurons and immune cells regulates many essential physiological functions including protection against mucosal infections. We previously demonstrated that following paraoxon treatment, 70 % of the mice were able to survive an oral infection with S. typhimurium, a virulent strain of Salmonella enterica serovar Typhimurium. The present study aims to investigate the effect that rivastigmine, a reversible AChE inhibitor used for the treatment of neurodegenerative diseases, has on the murine immune defenses of the intestinal mucosa. Our findings show that, similar to what is observed with paraoxon, administration of rivastigmine promoted the release of secretory granules from goblet and Paneth cells, resulting in increased mucin layer. Surprisingly, however, and unlike paraoxon, rivastigmine treatment did not affect overall mortality of infected mice. In order to investigate the mechanistic basis for the differential effects observed between paraoxon and rivastigmine, we used multi-color flowcytometric analysis to characterize the immune cell landscape in the intraepithelial (IE) and lamina propria (LP) compartments of intestinal mucosa. Our data indicate that treatment with paraoxon, but not rivastigmine, led to an increase of resident CD3+CD8+ T lymphocytes in the ileal mucosa (epithelium and lamina propria) and CD11b- CD11c+ dendritic cells in the LP. Our findings indicate the requirement for persistent cholinergic pathway engagement to effect a change in the cellular landscape of the mucosal tissue that is necessary for protection against lethal bacterial infections. Moreover, optimal protection requires a collaboration between innate and adaptive mucosal immune responses in the intestine.

Cutting Edge: ATP13A2 Is an Endolysosomal Regulator of TLR9/7 Activation in Human Plasmacytoid Dendritic Cells

ATPase cation transporting 13A2 (ATP13A2) is an endolysosomal P-type ATPase known to be a polyamine transporter, explored mostly in neurons. As endolysosomal functions are also crucial in innate immune cells, we aimed to explore the potential role of ATP13A2 in the human immunocellular compartment. We found that human plasmacytoid dendritic cells (pDCs), the professional type I IFN-producing immune cells, especially have a prominent enrichment of ATP13A2 expression in endolysosomal compartments. ATP13A2 knockdown in human pDCs interferes with cytokine induction in response to TLR9/7 activation in response to bona fide ligands. ATP13A2 plays this crucial role in TLR9/7 activation in human pDCs by regulating endolysosomal pH and mitochondrial reactive oxygen generation. This (to our knowledge) hitherto unknown regulatory mechanism in pDCs involving ATP13A2 opens up a new avenue of research, given the crucial role of pDC-derived type I IFNs in protective immunity against infections as well as in the immunopathogenesis of myriad contexts of autoreactive inflammation.

Harnessing Immunomodulatory Polymers for Treatment of Autoimmunity, Allergy, and Transplant Rejection

Autoimmunity, allergy, and transplant rejection are a collection of chronic diseases that are currently incurable, drastically decrease patient quality of life, and consume considerable health care resources. Underlying each of these diseases is a dysregulated immune system that results in the mounting of an inflammatory response against self or an innocuous antigen. As a consequence, afflicted patients are required to adhere to lifelong regimens of multiple immunomodulatory drugs to control disease and reclaim agency. Unfortunately, current immunomodulatory drugs are associated with a myriad of side effects and adverse events, such as increased risk of cancer and increased risk of serious infection, which negatively impacts patient adherence rates and quality of life. The field of immunoengineering is a new discipline that aims to harness endogenous biological pathways to thwart disease and minimize side effects using novel biomaterial-based strategies. We highlight and discuss polymeric micro/nanoparticles with inherent immunomodulatory properties that are currently under investigation in biomaterial-based therapies for treatment of autoimmunity, allergy, and transplant rejection.

The "root" causes behind the anti-inflammatory actions of ginger compounds in immune cells

Ginger (Zingiber officinale) is one of the most well-known spices and medicinal plants worldwide that has been used since ancient times to treat a plethora of diseases including cold, gastrointestinal complaints, nausea, and migraine. Beyond that, a growing body of literature demonstrates that ginger exhibits anti-inflammatory, antioxidant, anti-cancer and neuroprotective actions as well. The beneficial effects of ginger can be attributed to the biologically active compounds of its rhizome such as gingerols, shogaols, zingerone and paradols. Among these compounds, gingerols are the most abundant in fresh roots, and shogaols are the major phenolic compounds of dried ginger. Over the last two decades numerous in vitro and in vivo studies demonstrated that the major ginger phenolics are able to influence the function of various immune cells including macrophages, neutrophils, dendritic cells and T cells. Although the mechanism of action of these compounds is not fully elucidated yet, some studies provide a mechanistic insight into their anti-inflammatory effects by showing that ginger constituents are able to target multiple signaling pathways. In the first part of this review, we summarized the current literature about the immunomodulatory actions of the major ginger compounds, and in the second part, we focused on the possible molecular mechanisms that may underlie their anti-inflammatory effects.

STING-Targeted PET Imaging for Specific Detection and Therapeutic Monitoring of Myocarditis

Imaging strategies for the specific detection and therapeutic monitoring of myocarditis are still lacking. Stimulator of interferon genes (STING) is a signal transduction molecule involved in an innate immune response. Here, we evaluated the feasibility of the recently developed STING-targeted radiotracer [18F]FBTA for positron emission tomography (PET) imaging to detect myocardial inflammation and monitor treatment in myocarditis mice. [18F]FBTA-PET imaging was performed in myocarditis mice and normal mice to verify the specificity of [18F]FBTA for the diagnosis of myocarditis. We also performed PET imaging in mice with myocarditis treated to verify the ability of [18F]FBTA in therapeutic monitoring. The expression of STING and inflammatory cell types was confirmed by flow cytometry and immunohistochemistry. [18F]FDG-PET imaging of myocarditis was used as a contrast. [18F]FBTA-PET imaging showed that the average radioactive uptake was significantly higher in the hearts of the myocarditis group than in the control group. STING was highly overexpressed in cardiac inflammatory cells, including macrophages, dendritic cells (DCs), and T cells. However, there was no significant difference in cardiac radiotracer uptake of [18F]FDG between the myocarditis group and the control group. Moreover, cardiac uptake of [18F]FBTA was significantly reduced in cyclosporin A-treated myocarditis mice and myocardial STING expression was also significantly reduced after the treatment. Overall, we showed that a STING-targeted PET tracer [18F]FBTA can be used to monitor changes in the inflammatory microenvironment in myocarditis. Besides, [18F]FBTA-PET is also suitable for real-time monitoring of myocarditis treatment, representing a promising diagnostic and therapeutic monitoring approach for myocarditis.

Comprehensive pan-cancer analysis reveals VSIR as a candidate immunologic, diagnostic, and prognostic biomarker

OBJECTIVES

Being a checkpoint, the expression level of V-set immunoregulatory receptor (VSIR) serves as an indicator of the extent of immunosuppression. Our objective was to undertake a pan-cancer analysis to examine the expression, genetic alterations, prognosis, and immunologic features associated with VSIR.

METHODS

The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), GEPIA2, UALCAN, OncoDB, Human Protein Atlas (HPA), STRING, DAVID, cell culture, clinical sample collection, and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used.

RESULTS

This study comprehensively assessed VSIR across 33 cancers using TCGA and GTEx databases. Differential expression analysis revealed elevated VSIR in several cancers, notably in cholangiocarcinoma, esophageal carcinoma, kidney renal cell carcinoma, and liver hepatocellular carcinoma, while decreased expression was observed in various others. Prognostic analysis highlighted its significant association with reduced overall survival (OS) in ESCA and LIHC. Investigation into cancer stages demonstrated a correlation between VSIR expression and stage in ESCA and LIHC. Promoter methylation analysis indicated decreased VSIR methylation levels in tumors, implicating a role in oncogenesis. Furthermore, subcellular localization predictions, Tumor Mutational Burden (TMB), and Microsatellite Instability (MSI) correlations revealed intriguing insight into VSIR's function. Notably, a positive correlation was identified between VSIR expression and various immune cells in both cancers. Protein-protein interaction (PPI) network construction and gene enrichment analysis elucidated VSIR-associated dysregulated pathways, emphasizing its possible involvement in diverse pathways. Finally, experimental validation using LIHC clinical samples and cell lines confirmed elevated VSIR expression, supporting its oncogenic role.

CONCLUSION

Collectively, these findings present a comprehensive understanding of VSIR's diverse roles and potential clinical implications in ESCA and LIHC.

Differentiation, maturation, and collection of THP-1-derived dendritic cells based on a PEG hydrogel culture platform

PURPOSE

Dendritic cell (DC) is a spearhead responsible for immune response and surrounded by extracellular matrix in three-dimensional (3D) tissue. Nevertheless, conventional DC culture has relied on suspension or two-dimensional (2D) tissue culture plate (TCP)-based culture system. This culture condition often fails to recapitulate the physiological behavior of DC in real tissue. In this work, the effect of culture condition on DC physiology was explored with varying 3D hydrogel property (i.e., degradability, adhesion, and stiffness). In particular, DC differentiation and maturation in 3D were evaluated comparing the conventional TCP-based culture condition.

METHOD

THP-1 cells were encapsulated in poly(ethylene glycol) (PEG) hydrogel via thiol-ene photocrosslinking with non-degradable or proteolytically degradable peptide crosslinker. Hydrogel stiffness was manipulated by controlling the concentration of crosslinker. The metabolic activities and cytotoxicity of the encapsulated cells were measured by resazurin and Live/Dead assays, respectively. Cell harvesting was conducted via enzymatic degradation using α-chymotrypsin, and differentiation and maturation of the liberated DCs were evaluated by quantitative polymerase chain reaction and flow cytometry.

RESULTS

THP-1 cells well proliferated in the soft degradable hydrogel with a higher metabolic activity. However, the stiff matrix inhibited cell growth in 3D. The gene expression assay indicated that the 3D hydrogel condition was superior to 2D culture in terms of differentiation and maturation of DC. Interestingly, the stiffness of matrix was important factor in DC function. In the stiff hydrogel, the expression levels of differentiation and maturation markers were higher compared to the low stiffness hydrogel. The mature DCs caged in the hydrogel matrix were harvested after short enzymatic digestion of hydrogel and the liberated cells had over 90% viability. The flow cytometric result revealed that the proportion of CD80 + /CD86 + cells from the stiff hydrogel was relatively higher than cells either from 2D or soft hydrogel in 3D.

CONCLUSION

The collected evidence indicated that the proteolytically degradable PEG hydrogel matrix promoted DC differentiation and maturation. In addition, the matrix stiffness control could manipulate the marker expressions of differentiation and maturation. Particularly, the mature DC was successfully collected from the hydrogel matrix. These results highlighted the PEG hydrogel-based DC culture might be a useful tool for potential DC-based immunotherapies.

Ginger-derived bioactive compounds attenuate the Toll-like receptor mediated responses of human dendritic cells

Ginger has been used for thousands of years for the treatment of many illnesses, from nausea to migraines. Recently, an interest has grown in ginger compounds in the context of autoimmune and inflammatory diseases due to their significant anti-inflammatory effects. Nevertheless, the effects and mechanism of action of these phytochemicals in human immune cells, particularly in dendritic cells (DCs) are unclear. In the present study, we investigated the effects of 6-gingerol and 6-shogaol, the major compounds found in ginger rhizome, on the functionality of primary human monocyte-derived DCs (moDCs). Here we report for the first time that 6-gingerol and 6-shogaol dampen the immunogenicity of human DCs by inhibiting their activation, cytokine production and T cell stimulatory ability. In particular, the bioactive compounds of ginger dose-dependently inhibited the upregulation of activation markers, and the production of different cytokines in response to synthetic Toll-like receptor (TLR) ligands. Moreover, both compounds could significantly reduce the Escherichia coli-triggered cytokine production and T cell stimulatory capacity of moDCs. We also provide evidence that the ginger-derived compounds attenuate DC functionality via inhibiting the nuclear factor-κB (NF-kB), mitogen activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) signaling cascades. Further, 6-shogaol but not 6-gingerol activates the AMP-activated protein kinase (AMPK) and nuclear factor erythroid 2-related factor 2 (NRF2) pathways that might contribute to its anti-inflammatory action. Altogether, our results indicate that ginger-derived phytochemicals exert their anti-inflammatory activities via multiple mechanisms and suggest that 6-shogaol is more potent in its ability to suppress DC functionality than 6-gingerol.

Bona fide dendritic cells are pivotal precursors for osteoclasts

OBJECTIVES

Osteoclasts (OCs) are myeloid-derived multinucleated cells uniquely able to degrade bone. However, the exact nature of their myeloid precursors is not yet defined.

METHODS

CD11c-diphtheria toxin receptor (CD11cDTR) transgenic mice were treated with diphtheria toxin (DT) or phosphate buffered saline (PBS) during serum transfer arthritis (STA) and human tumour necrosis factor transgenic (hTNFtg) arthritis and scored clinically and histologically. We measured cytokines in synovitis by quantitative polymerase chain reaction (qPCR). We performed ovariectomy in CD11cDTR mice treated with PBS or DT. We analysed CD11cDTR, CD11c-Cre/CX3CR1-STOP-DTR and Zbtb46-DTR-treated mice with DT using histomorphometry and OC of CD11c and Zbtb46 fate reporter mice by fluorescent imaging. We sorted murine and human OC precursors and stimulated them with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL) to generate OCs.

RESULTS

Targeting CD11c+ cells in vivo in models of inflammatory arthritis (STA and hTNFtg) ameliorates arthritis by reducing inflammatory bone destruction and OC generation. Targeting CD11c-expressing cells in unchallenged mice removes all OCs in their long bones. OCs do not seem to be derived from CD11c+ cells expressing CX3CR1+, but from Zbtb46+conventional dendritic cells (cDCs) as all OCs in Zbtb46-Tomato fate reporter mice are Tomato+. In line, administration of DT in Zbtb46-DTR mice depletes all OCs in long bones. Finally, human CD1c-expressing cDCs readily differentiated into bone resorbing OCs.

CONCLUSION

Taken together, we identify DCs as important OC precursors in bone homeostasis and inflammation, which might open new avenues for therapeutic interventions in OC-mediated diseases.

Berberine: A natural modulator of immune cells in multiple sclerosis

Berberine is a benzylisoquinoline alkaloid found in such plants as Berberis vulgaris, Berberis aristata, and others, revealing a variety of pharmacological properties as a result of interacting with different cellular and molecular targets. Recent studies have shown the immunomodulatory effects of Berberine which result from its impacts on immune cells and immune response mediators such as diverse T lymphocyte subsets, dendritic cells (DCs), and different inflammatory cytokines. Multiple sclerosis (MS) is a chronic disabling and neurodegenerative disease of the central nervous system (CNS) characterized by the recruitment of autoreactive T cells into the CNS causing demyelination, axonal damage, and oligodendrocyte loss. There have been considerable changes discovered in MS regards to the function and frequency of T cell subsets such as Th1 cells, Th17 cells, Th2 cells, Treg cells, and DCs. In the current research, we reviewed the outcomes of in vitro, experimental, and clinical investigations concerning the modulatory effects that Berberine provides on the function and numbers of T cell subsets and DCs, as well as important cytokines that are involved in MS.

Traditional Chinese Medicine Shi-Bi-Man ameliorates psoriasis via inhibiting IL-23/Th17 axis and CXCL16-mediated endothelial activation

BACKGROUND

Psoriasis is a chronic inflammatory genetic disease, mainly manifesting in the skin. Conventional therapies, such as glucocorticosteroids and corticosteroids, have adverse effects that limit drug use. Hence, it is imperative to identify a new therapeutic strategy that exhibits a favorable safety profile. Shi-Bi-Man (SBM) is a safe herbal supplement sourced from various natural plants, including ginseng, angelica sinensis, polygonum multiflorum, and aloe vera.

PURPOSE

We aimed to find a potential treatment for psoriasis and investigate the underlying mechanism through which SBM alleviates psoriatic-like skin inflammation in mice.

METHODS

We investigated the effects of supplementing with SBM through intragastric administration or smear administration in a murine model of imiquimod-induced psoriasis. The changes in body weight and Psoriasis Area and Severity Index (PASI) score were recorded throughout the entire process. Additionally, we used hematoxylin-eosin staining to observe the skin structure and performed single-cell RNA sequencing to explore the underlying mechanism of SBM in influencing the psoriasis-like phenotype. Immunofluorescence was conducted to verify our findings. Furthermore, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was employed to investigate the impact of Tetrahydroxy stilbene glycoside (TSG) on the expression levels of IL23 in HaCaT cells.

RESULTS

SBM remarkably alleviated the psoriasis-like phenotype by inhibiting IL-23/Th17 cell axis. Single-cell RNA sequencing analysis revealed a decrease in the expression of Il17 and Il23 in keratinocytes and T cells, concomitant with a reduction in the proportion of Th17 cells. Meanwhile, the activation of endothelial cells was inhibited, accompanied by a decrease in the expression of Cxcl16. In vitro, the addition of TSG to HaCaT cells resulted in significant suppression of IL23 expression stimulated by tumor necrosis factor-alpha (TNF-α).

B Cell-mediated Immune Regulation and the Quest for Transplantation Tolerance

Pathophysiologic function of B cells in graft rejection has been well recognized in transplantation. B cells promote alloantigen-specific T-cell response and secrete antibodies that can cause antibody-mediated graft failures and rejections. Therefore, strategies targeting B cells, for example, B-cell depletion, have been used for the prevention of both acute and chronic rejections. Interestingly, however, recent mounting evidence indicates that subsets of B cells yet to be further identified can display potent immune regulatory functions, and they contribute to transplantation tolerance and operational tolerance in both experimental and clinical settings, respectively. In this review, we integrate currently available information on B-cell subsets, including T-cell Ig domain and mucin domain 1-positive transitional and T-cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif domain-positive memory B cells, displaying immune regulatory functions, with a focus on transplantation tolerance, by analyzing their mechanisms of action. In addition, we will discuss potential T-cell Ig domain and mucin domain 1-positive and T-cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif domain-positive B cell-based strategies for the enhancement of operational tolerance in transplantation patients.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

Role of immune cells in the pathogenesis of myocarditis

Myocarditis is an inflammatory heart disease that mostly affects young people. Myocarditis involves a complex immune network; however, its detailed pathogenesis is currently unclear. The diversity and plasticity of immune cells, either in the peripheral blood or in the heart, have been partially revealed in a number of previous studies involving patients and several kinds of animal models with myocarditis. It is the complexity of immune cells, rather than one cell type that is the culprit. Thus, recognizing the individual intricacies within immune cells in the context of myocarditis pathogenesis and finding the key intersection of the immune network may help in the diagnosis and treatment of this condition. With the vast amount of cell data gained on myocarditis and the recent application of single-cell sequencing, we summarize the multiple functions of currently recognized key immune cells in the pathogenesis of myocarditis to provide an immune background for subsequent investigations.

The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by the destruction of the myelin sheath of the neuronal axon in the central nervous system. Many risk factors, including environmental, epigenetic, genetic, and lifestyle factors, are responsible for the development of MS. It has long been thought that only adaptive immune cells, especially autoreactive T cells, are responsible for the pathophysiology; however, recent evidence has indicated that innate immune cells are also highly involved in disease initiation and progression. Here, we compile the available data regarding the role immune cells play in MS, drawn from both human and animal research. While T and B lymphocytes, chiefly enhance MS pathology, regulatory T cells (Tregs) may serve a more protective role, as can B cells, depending on context and location. Cells chiefly involved in innate immunity, including macrophages, microglia, astrocytes, dendritic cells, natural killer (NK) cells, eosinophils, and mast cells, play varied roles. In addition, there is evidence regarding the involvement of innate-like immune cells, such as γδ T cells, NKT cells, MAIT cells, and innate-like B cells as crucial contributors to MS pathophysiology. It is unclear which of these cell subsets are involved in the onset or progression of disease or in protective mechanisms due to their plastic nature, which can change their properties and functions depending on microenvironmental exposure and the response of neural networks in damage control. This highlights the need for a multipronged approach, combining stringently designed clinical data with carefully controlled in vitro and in vivo research findings, to identify the underlying mechanisms so that more effective therapeutics can be developed.

Helios as a Potential Biomarker in Systemic Lupus Erythematosus and New Therapies Based on Immunosuppressive Cells

The Helios protein (encoded by the IKZF2 gene) is a member of the Ikaros transcription family and it has recently been proposed as a promising biomarker for systemic lupus erythematosus (SLE) disease progression in both mouse models and patients. Helios is beginning to be studied extensively for its influence on the T regulatory (Treg) compartment, both CD4+ Tregs and KIR+/Ly49+ CD8+ Tregs, with alterations to the number and function of these cells correlated to the autoimmune phenomenon. This review analyzes the most recent research on Helios expression in relation to the main immune cell populations and its role in SLE immune homeostasis, specifically focusing on the interaction between T cells and tolerogenic dendritic cells (tolDCs). This information could be potentially useful in the design of new therapies, with a particular focus on transfer therapies using immunosuppressive cells. Finally, we will discuss the possibility of using nanotechnology for magnetic targeting to overcome some of the obstacles related to these therapeutic approaches.

ROS-Scavenging Lignin-Based Tolerogenic Nanoparticle Vaccine for Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating autoimmune disease, in which the immune system attacks myelin. Although systemic immunosuppressive agents have been used to treat MS, long-term treatment with these drugs causes undesirable side effects such as altered glucose metabolism, insomnia, and hypertension. Herein, we propose a tolerogenic therapeutic vaccine to treat MS based on lignin nanoparticles (LNP) with intrinsic reactive oxygen species (ROS)-scavenging capacity derived from their phenolic moieties. The LNP loaded with autoantigens of MS allowed for inducing tolerogenic DCs with low-level expression of costimulatory molecules while presenting antigenic peptides. Intravenous injection of an LNP-based tolerogenic vaccine into an experimental autoimmune encephalomyelitis (EAE) model led to durable antigen-specific immune tolerance via inducing regulatory T cells (Tregs). Autoreactive T helper type 1 cells, T helper type 17 cells, and inflammatory antigen presentation cells (APCs) were suppressed in the central nervous system (CNS), ameliorating ongoing MS in early and late disease states. Additionally, the incorporation of dexamethasone into an LNP-based tolerogenic nanovaccine could further improve the recovery of EAE mice in the severe chronic stage. As lignin is the most abundant biomass and waste byproduct in the pulping industry, a lignin-based tolerogenic vaccine could be a novel, cost-effective, high-value vaccine platform with potent therapeutic efficiency in treating autoimmune diseases.

RelB-deficient autoinflammatory pathology presents as interferonopathy, but in mice is interferon-independent

BACKGROUND

Autoimmune diseases are leading causes of ill health and morbidity and have diverse etiology. Two signaling pathways are key drivers of autoimmune pathology, interferon and nuclear factor-κB (NF-κB)/RelA, defining the 2 broad labels of interferonopathies and relopathies. Prior work has established that genetic loss of function of the NF-κB subunit RelB leads to autoimmune and inflammatory pathology in mice and humans.

OBJECTIVE

We sought to characterize RelB-deficient autoimmunity by unbiased profiling of the responses of immune sentinel cells to stimulus and to determine the functional role of dysregulated gene programs in the RelB-deficient pathology.

METHODS

Transcriptomic profiling was performed on fibroblasts and dendritic cells derived from patients with RelB deficiency and knockout mice, and transcriptomic responses and pathology were assessed in mice deficient in both RelB and the type I interferon receptor.

RESULTS

We found that loss of RelB in patient-derived fibroblasts and mouse myeloid cells results in elevated induction of hundreds of interferon-stimulated genes. Removing hyperexpression of the interferon-stimulated gene program did not ameliorate the autoimmune pathology of RelB knockout mice. Instead, we found that RelB suppresses a different set of inflammatory response genes in a manner that is independent of interferon signaling but associated with NF-κB binding motifs.

CONCLUSION

Although transcriptomic profiling would describe RelB-deficient autoimmune disease as an interferonopathy, the genetic evidence indicates that the pathology in mice is interferon-independent.

Tolerogenic dendritic cells and TLR4/IRAK4/NF-κB signaling pathway in allergic rhinitis

Dendritic cells (DCs), central participants in the allergic immune response, can capture and present allergens leading to allergic inflammation in the immunopathogenesis of allergic rhinitis (AR). In addition to initiating antigen-specific immune responses, DCs induce tolerance and modulate immune homeostasis. As a special type of DCs, tolerogenic DCs (tolDCs) achieve immune tolerance mainly by suppressing effector T cell responses and inducing regulatory T cells (Tregs). TolDCs suppress allergic inflammation by modulating immune tolerance, thereby reducing symptoms of AR. Activation of the TLR4/IRAK4/NF-κB signaling pathway contributes to the release of inflammatory cytokines, and inhibitors of this signaling pathway induce the production of tolDCs to alleviate allergic inflammatory responses. This review focuses on the relationship between tolDCs and TLR4/IRAK4/NF-κB signaling pathway with AR.

Association of thyroid peroxidase antibody with the RNF213 p.R4810K variant in ischemic stroke/transient ischemic attack

BACKGROUND AND AIMS

RNF213 is a susceptibility gene for moyamoya disease and vasospastic angina, with a second hit considered necessary for their development. Elevated thyroid peroxidase antibody (TPO-Ab) levels have been observed in both diseases, suggesting a possible role of TPO-Ab as a second hit for developing RNF213-related vasculopathy. We investigated the association of TPO-Ab levels with RNF213-related ischemic stroke (IS)/transient ischemic attack (TIA), other than moyamoya disease.

METHODS

From the National Cerebral and Cardiovascular Center Genome Registry, a multicenter, prospective, observational study, we enrolled patients with IS/TIA who were admitted within 1 week of onset. Patients with IS/TIA due to definite moyamoya disease or hemorrhagic stroke were excluded. Participants underwent genotyping for RNF213 p. R4810K, and baseline characteristics and TPO-Ab levels were compared between RNF213 p. R4810K variant carriers and non-carriers.

RESULTS

In total, 2090 IS/TIA patients were analyzed [733 women (35.1%); median age 74 (interquartile range, 63-81) years, baseline NIHSS score 3 (2-6)], and 85 (4.1%) of them carried the variant. Median TPO-Ab levels were significantly higher in variant carriers (8.5 IU/mL vs. 2.1 IU/mL, p < 0.01), who also showed a higher frequency of elevated TPO-Ab levels (>16 IU/mL) (27.1% vs. 4.4%). In the multivariate analysis, presence of the RNF213 p. R4810K variant (adjusted odds ratio, 12.42; 95% confidential interval, 6.23-24.75) was significantly associated with elevated TPO-Ab levels.

CONCLUSIONS

Elevated TPO-Ab levels may be significantly associated with presence of the RNF213 p. R4810K variant in IS/TIA patients. Thus, TPO-Ab may inherently modify IS/TIA development in RNF213 p. R4810K variant carriers.

Tackling TNF-α in autoinflammatory disorders and autoimmune diseases: From conventional to cutting edge in biologics and RNA- based nanomedicines

Autoinflammatory disorders and autoimmune diseases result from abnormal deviations of innate and adaptive immunity that heterogeneously affect organs and clinical phenotypes. Despite having etiologic and phenotypic differences, these two conditions share the onset of an aberrant inflammatory process. Targeting the main drivers controlling inflammation is useful to treat both autoimmune and autoinflammatory syndromes. TNF-α is a major player in the inflammatory immune response, and anti-TNF-α antibodies have been a revolutionary treatment in many autoimmune disorders. However, production difficulties and high development costs hinder their implementation, and accessibility to their use is still limited. Innovative strategies aimed at overcoming the limitations associated with anti-TNF-α antibodies are being explored, including RNA-based therapies. Here we summarize the central role of TNF-α in immune disorders and how anti-TNF-based immunotherapies changed the therapeutic landscape, albeit with important limitations related to side effects, tolerance, and resistance to therapies. We then outline how nanotechnology has provided the final momentum for the use of nucleic acids in the treatment of autoimmune and autoinflammatory diseases, with a focus on inflammatory bowel diseases (IBDs). The example of IBDs allows the evaluation and discussion of the nucleic acids-based treatments that have been developed, to identify the role that innovative approaches possess in view of the treatment of autoinflammatory disorders and autoimmune diseases.

Mitochondrial sourcing of interferogenic ligands and an autoantigen in human obesity-associated metaflammation

OBJECTIVE

Visceral adipose tissue (VAT) inflammation contributes to metabolic dysregulation in obesity. VAT recruitment and activation of plasmacytoid dendritic cells (pDCs) through toll-like receptor 9 (TLR9) recognition of self-DNA, leading to induction of type I interferons, are crucial innate triggers for this VAT inflammation. It was hypothesized that mitochondrial DNA (mtDNA) can contribute to TLR9 activation in VAT-recruited pDCs in obesity, and this study aimed to identify the carrier protein for ligand access to TLR9 and to explore whether this also provides for a source of autoantigens in this context.

METHODS

VAT samples, used for gene expression studies as well as adipose explant cultures, were collected from patients with obesity (n = 54) and lean patients (n = 10). Supernatants from human pDC cultures, treated with adipose explant culture supernatants, were used for interferon α ELISA. Venous plasma, from patients with (n = 114) and without (n = 45) obesity, was used for an ELISA for autoantibodies.

RESULTS

MtDNA from VAT in obesity, in complex with mitochondrial transcription factor A protein (TFAM), acts as interferogenic ligands for pDCs. Humoral autoreactivity against TFAM is also induced in obesity.

CONCLUSIONS

Interferogenic ligands and an autoantigen can be sourced from dysfunctional mitochondria in VAT of humans with obesity. Further therapeutic and prognostic potential for this immune mechanism in obesity warrants exploration.

The developing role of extracellular vesicles in autoimmune diseases: special attention to mesenchymal stem cell-derived extracellular vesicles

Autoimmune diseases are complex, chronic inflammatory conditions initiated by the loss of immunological tolerance to self-antigens. Nowadays, there is no effective and useful therapy for autoimmune diseases, and the existing medications have some limitations due to their nonspecific targets and side effects. During the last few decades, it has been established that mesenchymal stem cells (MSCs) have immunomodulatory functions. It is proposed that MSCs can exert an important therapeutic effect on autoimmune disorders. In parallel with these findings, several investigations have shown that MSCs alleviate autoimmune diseases. Intriguingly, the results of studies have demonstrated that the effective roles of MSCs in autoimmune diseases do not depend on direct intercellular communication but on their ability to release a wide spectrum of paracrine mediators such as growth factors, cytokines and extracellular vehicles (EVs). EVs that range from 50 to 5,000 nm were produced by almost any cell type, and these nanoparticles participate in homeostasis and intercellular communication via the transfer of a broad range of biomolecules such as modulatory proteins, nucleic acids (DNA and RNA), lipids, cytokines, and metabolites. EVs derived from MSCs display the exact properties of MSCs and can be safer and more beneficial than their parent cells. In this review, we will discuss the features of MSCs and their EVs, EVs biogenesis, and their cargos, and then we will highlight the existing discoveries on the impacts of EVs from MSCs on autoimmune diseases such as multiple sclerosis, arthritis rheumatic, inflammatory bowel disease, Type 1 diabetes mellitus, systemic lupus erythematosus, autoimmune liver diseases, Sjögren syndrome, and osteoarthritis, suggesting a potential alternative for autoimmune conditions therapy.

SLC38A5 aggravates DC-mediated psoriasiform skin inflammation via potentiating lysosomal acidification

Amino acid (aa) metabolism is closely correlated with the pathogenesis of psoriasis; however, details on aa transportation during this process are barely known. Here, we find that SLC38A5, a sodium-dependent neutral aa transporter that counter-transports protons, is markedly upregulated in the psoriatic skin of both human patients and mouse models. SLC38A5 deficiency significantly ameliorates the pathogenesis of psoriasis, indicating a pathogenic role of SLC38A5. Surprisingly, SLC38A5 is almost exclusively expressed in dendritic cells (DCs) when analyzing the psoriatic lesion and mainly locates on the lysosome. Mechanistically, SLC38A5 potentiates lysosomal acidification, which dictates the cleavage and activation of TLR7 with ensuing production of pro-inflammatory cytokines such as interleukin-23 (IL-23) and IL-1β from DCs and eventually aggravates psoriatic inflammation. In summary, this work uncovers an auxiliary mechanism in driving lysosomal acidification, provides inspiring insights for DC biology and psoriasis etiology, and reveals SLC38A5 as a promising therapeutic target for treating psoriasis.

Metabolic enzyme Suclg2 maintains tolerogenicity of regulatory dendritic cells diffDCs by suppressing Lactb succinylation

Metabolic reprogramming plays a pivotal role in the differentiation and function of immune cells including dendritic cells (DCs). Regulatory DCs can be generated in regional tissue niches like splenic stroma and act as an important part of stromal control of immune response for the maintenance of immune tolerance. However, the metabolic alterations during splenic stroma-driven regulatory DCs differentiation and the metabolic enzyme involved in regulatory DCs function remain poorly understood. By combining metabolomic, transcriptomic, and functional investigations of mature DCs (maDCs) and diffDCs (regulatory DCs differentiated from activated mature DCs through coculturing with splenic stroma), here we identified succinate-CoA ligase subunit beta Suclg2 as a key metabolic enzyme that reprograms the proinflammatory status of mature DCs into a tolerogenic phenotype via preventing NF-κB signaling activation. diffDCs downregulate succinic acid levels and increase the Suclg2 expression along with their differentiation from mature DCs. Suclg2-interference impaired the tolerogenic function of diffDCs in inducing T cell apoptosis and enhanced activation of NF-κB signaling and expression of inflammatory genes CD40, Ccl5, and Il12b in diffDCs. Furthermore, we identified Lactb as a new positive regulator of NF-κB signaling in diffDCs whose succinylation at the lysine 288 residue was inhibited by Suclg2. Our study reveals that the metabolic enzyme Suclg2 is required to maintain the immunoregulatory function of diffDCs, adding mechanistic insights into the metabolic regulation of DC-based immunity and tolerance.

Signaling pathways involved in the biological functions of dendritic cells and their implications for disease treatment

The ability of dendritic cells (DCs) to initiate and regulate adaptive immune responses is fundamental for maintaining immune homeostasis upon exposure to self or foreign antigens. The immune regulatory function of DCs is strictly controlled by their distribution as well as by cytokines, chemokines, and transcriptional programming. These factors work in conjunction to determine whether DCs exert an immunosuppressive or immune-activating function. Therefore, understanding the molecular signals involved in DC-dependent immunoregulation is crucial in providing insight into the generation of organismal immunity and revealing potential clinical applications of DCs. Considering the many breakthroughs in DC research in recent years, in this review we focused on three basic lines of research directly related to the biological functions of DCs and summarized new immunotherapeutic strategies involving DCs. First, we reviewed recent findings on DC subsets and identified lineage-restricted transcription factors that guide the development of different DC subsets. Second, we discussed the recognition and processing of antigens by DCs through pattern recognition receptors, endogenous/exogenous pathways, and the presentation of antigens through peptide/major histocompatibility complexes. Third, we reviewed how interactions between DCs and T cells coordinate immune homeostasis in vivo via multiple pathways. Finally, we summarized the application of DC-based immunotherapy for autoimmune diseases and tumors and highlighted potential research prospects for immunotherapy that targets DCs. This review provides a useful resource to better understand the immunomodulatory signals involved in different subsets of DCs and the manipulation of these immune signals can facilitate DC-based immunotherapy.

Tacrolimus and paclitaxel co-loaded O/O ointment without surfactant: Synergistic combinations for the treatment of psoriasis

Psoriasis is an autoimmune disorder disease with abnormally activated T lymphocytes and thickening of the epidermis. The mechanism of the action of tacrolimus and paclitaxel are matched with the two only known pathogenesis of psoriasis. However, there has been no report on tacrolimus combined with paclitaxel in the treatment of psoriasis until now. The O/O ointment was prepared for the topical application to overcome poor solubility, poor skin penetration, and erratic absorption of the two drugs. A high-speed shearing method was adopted to prepare the ointment, in which propylene carbonate was used to solve tacrolimus and paclitaxel completely. The ointment showed excellent stability, slow release of the drugs, better retention in psoriatic skin, and good skin tolerance. The therapeutic efficacy of ointment was evaluated with imiquimod induced psoriatic model, and the level of expression of psoriatic biochemical markers was evaluated using the PASI score and immunohistochemistry. The cumulative PASI score was 10.8 for the imiquimod induced group, 7.8 for the tacrolimus ointment group, 8.3 for the paclitaxel ointment and 5.3 for the tacrolimus-paclitaxel (1:1) ointment group, respectively. Ointment group with tacrolimus and paclitaxel indicated a significant improvement in the phenotypic features of the psoriatic skin treated. Compared with the imiquimod group, tacrolimus-paclitaxel (1:1) ointment group was significantly reduced the level of IL-17. The results confirm that tacrolimus and paclitaxel co-loaded ointment can be an effective strategy for the treatment of psoriasis.

A multiscale mechanistic model of human dendritic cells for in-silico investigation of immune responses and novel therapeutics discovery

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) with the unique ability to mediate inflammatory responses of the immune system. Given the critical role of DCs in shaping immunity, they present an attractive avenue as a therapeutic target to program the immune system and reverse immune disease disorders. To ensure appropriate immune response, DCs utilize intricate and complex molecular and cellular interactions that converge into a seamless phenotype. Computational models open novel frontiers in research by integrating large-scale interaction to interrogate the influence of complex biological behavior across scales. The ability to model large biological networks will likely pave the way to understanding any complex system in more approachable ways. We developed a logical and predictive model of DC function that integrates the heterogeneity of DCs population, APC function, and cell-cell interaction, spanning molecular to population levels. Our logical model consists of 281 components that connect environmental stimuli with various layers of the cell compartments, including the plasma membrane, cytoplasm, and nucleus to represent the dynamic processes within and outside the DC, such as signaling pathways and cell-cell interactions. We also provided three sample use cases to apply the model in the context of studying cell dynamics and disease environments. First, we characterized the DC response to Sars-CoV-2 and influenza co-infection by in-silico experiments and analyzed the activity level of 107 molecules that play a role in this co-infection. The second example presents simulations to predict the crosstalk between DCs and T cells in a cancer microenvironment. Finally, for the third example, we used the Kyoto Encyclopedia of Genes and Genomes enrichment analysis against the model's components to identify 45 diseases and 24 molecular pathways that the DC model can address. This study presents a resource to decode the complex dynamics underlying DC-derived APC communication and provides a platform for researchers to perform in-silico experiments on human DC for vaccine design, drug discovery, and immunotherapies.

CTCF controls three-dimensional enhancer network underlying the inflammatory response of bone marrow-derived dendritic cells

Dendritic cells are antigen-presenting cells orchestrating innate and adaptive immunity. The crucial role of transcription factors and histone modifications in the transcriptional regulation of dendritic cells has been extensively studied. However, it is not been well understood whether and how three-dimensional chromatin folding controls gene expression in dendritic cells. Here we demonstrate that activation of bone marrow-derived dendritic cells induces extensive reprogramming of chromatin looping as well as enhancer activity, both of which are implicated in the dynamic changes in gene expression. Interestingly, depletion of CTCF attenuates GM-CSF-mediated JAK2/STAT5 signaling, resulting in defective NF-κB activation. Moreover, CTCF is necessary for establishing NF-κB-dependent chromatin interactions and maximal expression of pro-inflammatory cytokines, which prime Th1 and Th17 cell differentiation. Collectively, our study provides mechanistic insights into how three-dimensional enhancer networks control gene expression during bone marrow-derived dendritic cells activation, and offers an integrative view of the complex activities of CTCF in the inflammatory response of bone marrow-derived dendritic cells.

RBP-RNA interactions in the control of autoimmunity and autoinflammation

Autoimmunity and autoinflammation arise from aberrant immunological and inflammatory responses toward self-components, contributing to various autoimmune diseases and autoinflammatory diseases. RNA-binding proteins (RBPs) are essential for immune cell development and function, mainly via exerting post-transcriptional regulation of RNA metabolism and function. Functional dysregulation of RBPs and abnormities in RNA metabolism are closely associated with multiple autoimmune or autoinflammatory disorders. Distinct RBPs play critical roles in aberrant autoreactive inflammatory responses via orchestrating a complex regulatory network consisting of DNAs, RNAs and proteins within immune cells. In-depth characterizations of RBP-RNA interactomes during autoimmunity and autoinflammation will lead to a better understanding of autoimmune pathogenesis and facilitate the development of effective therapeutic strategies. In this review, we summarize and discuss the functions of RBP-RNA interactions in controlling aberrant autoimmune inflammation and their potential as biomarkers and therapeutic targets.

Conventional dendritic cells type 1 are strongly enriched, quiescent and relatively tolerogenic in local inflammatory arthritis

Introduction

Dendritic cells (DC) are crucial for initiating and shaping immune responses. So far, little is known about the functional specialization of human DC subsets in (local) inflammatory conditions. We profiled conventional (c)DC1, cDC2 and monocytes based on phenotype, transcriptome and function from a local inflammatory site, namely synovial fluid (SF) from patients suffering from a chronic inflammatory condition, Juvenile Idiopathic Arthritis (JIA) as well as patients with rheumatoid arthritis (RA).

Methods

Paired PB and SF samples from 32 JIA and 4 RA patients were collected for mononuclear cell isolation. Flow cytometry was done for definition of antigen presenting cell (APC) subsets. Cell sorting was done on the FACSAria II or III. RNA sequencing was done on SF APC subsets. Proliferation assays were done on co-cultures after CD3 magnetic activated cell sorting (MACS). APC Toll-like receptor (TLR) stimulation was done using Pam3CSK4, Poly(I:C), LPS, CpG-A and R848. Cytokine production was measured by Luminex.

Results

cDC1, a relatively small DC subset in blood, are strongly enriched in SF, and showed a quiescent immune signature without a clear inflammatory profile, low expression of pathogen recognition receptors (PRRs), chemokine and cytokine receptors, and poor induction of T cell proliferation and cytokine production, but selective production of IFNλ upon polyinosinic:polycytidylic acid exposure. In stark contrast, cDC2 and monocytes from the same environment, showed a pro-inflammatory transcriptional profile, high levels of (spontaneous) pro-inflammatory cytokine production, and strong induction of T cell proliferation and cytokine production, including IL-17. Although the cDC2 and monocytes showed an overlapping transcriptional core profile, there were clear differences in the transcriptional landscape and functional features, indicating that these cell types retain their lineage identity in chronic inflammatory conditions.

Discussion

Our findings suggest that at the site of inflammation, there is specific functional programming of human DCs, especially cDC2. In contrast, the enriched cDC1 remain relatively quiescent and seemingly unchanged under inflammatory conditions, pointing to a potentially more regulatory role.

Extracellular vesicles and their cells of origin: Open issues in autoimmune diseases

The conventional therapeutic approaches to treat autoimmune diseases through suppressing the immune system, such as steroidal and non-steroidal anti-inflammatory drugs, are not adequately practical. Moreover, these regimens are associated with considerable complications. Designing tolerogenic therapeutic strategies based on stem cells, immune cells, and their extracellular vesicles (EVs) seems to open a promising path to managing autoimmune diseases' vast burden. Mesenchymal stem/stromal cells (MSCs), dendritic cells, and regulatory T cells (Tregs) are the main cell types applied to restore a tolerogenic immune status; MSCs play a more beneficial role due to their amenable properties and extensive cross-talks with different immune cells. With existing concerns about the employment of cells, new cell-free therapeutic paradigms, such as EV-based therapies, are gaining attention in this field. Additionally, EVs' unique properties have made them to be known as smart immunomodulators and are considered as a potential substitute for cell therapy. This review provides an overview of the advantages and disadvantages of cell-based and EV-based methods for treating autoimmune diseases. The study also presents an outlook on the future of EVs to be implemented in clinics for autoimmune patients.

Tissue-Targeted Drug Delivery Strategies to Promote Antigen-Specific Immune Tolerance

During autoimmunity or organ transplant rejection, the immune system attacks host or transplanted tissue, causing debilitating inflammation for millions of patients. There is no cure for most of these diseases. Further, available therapies modulate inflammation through nonspecific pathways, reducing symptoms but also compromising patients' ability to mount healthy immune responses. Recent preclinical advances to regulate immune dysfunction with vaccine-like antigen specificity reveal exciting opportunities to address the root cause of autoimmune diseases and transplant rejection. Several of these therapies are currently undergoing clinical trials, underscoring the promise of antigen-specific tolerance. Achieving antigen-specific tolerance requires precision and often combinatorial delivery of antigen, cytokines, small molecule drugs, and other immunomodulators. This can be facilitated by biomaterial technologies, which can be engineered to orient and display immunological cues, protect against degradation, and selectively deliver signals to specific tissues or cell populations. In this review, some key immune cell populations involved in autoimmunity and healthy immune tolerance are described. Opportunities for drug delivery to immunological organs are discussed, where specialized tissue-resident immune cells can be programmed to respond in unique ways toward antigens. Finally, cell- and biomaterial-based therapies to induce antigen-specific immune tolerance that are currently undergoing clinical trials are highlighted.

The emerging role of regulatory cell-based therapy in autoimmune disease

Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

Immunogenomic correlates of immune-related adverse events for anti-programmed cell death 1 therapy

Despite impressive antitumor efficacy of programmed cell death 1 (PD-1) inhibitors, this inhibition can induce mild to severe autoimmune toxicities, termed immune-related adverse events (irAEs). Yet, predictive pretreatment biomarkers for irAEs development across cancer types remain elusive. We first assessed cellular and molecular factors. To determine factors predicting the risk of irAEs for anti-PD-1 immunotherapy across multiple cancer types, an integrative analysis of cellular and molecular factors from 9104 patients across 21 cancer types and 4865522 postmarketing adverse event reports retrieved from adverse event reporting system was then performed. Accuracy of predictions was quantified as Pearson correlation coefficient determined using leave-one-out cross-validation. Independent validation sets included small cell lung cancer and melanoma cohorts. Out of 4865522 eligible adverse events reports, 10412 cases received anti-PD-1 monotherapy, of which, 2997 (28.78%) exhibited at least one irAE. Among established immunogenomic factors, dendritic cells (DC) abundance showed the strongest correlation with irAEs risk, followed by tumor mutational burden (TMB). Further predictive accuracy was achieved by DC and TMB in combination with CD4⁺ naive T-cells abundance, and then validated in the small cell lung cancer cohort. Additionally, global screening of multiomics data identified 11 novel predictors of irAEs. Of these, IRF4 showed the highest correlation. Best predictive performance was observed in the IRF4 - TCL1A - SHC-pY317 trivariate model. Associations of IRF4 and TCL1A expression with irAEs development were verified in the melanoma cohort receiving immune checkpoint inhibitors. Collectively, pretreatment cellular and molecular irAEs-associated features as well as their combinations are identified regardless of cancer types. These findings may deepen our knowledge of irAEs pathogenesis and, ultimately, aid in early detection of high-risk patients and management of irAEs.

Advanced Glycation End Products and Inflammation in Type 1 Diabetes Development

Type 1 diabetes (T1D) is an autoimmune disease in which the β-cells of the pancreas are attacked by the host's immune system, ultimately resulting in hyperglycemia. It is a complex multifactorial disease postulated to result from a combination of genetic and environmental factors. In parallel with increasing prevalence of T1D in genetically stable populations, highlighting an environmental component, consumption of advanced glycation end products (AGEs) commonly found in in Western diets has increased significantly over the past decades. AGEs can bind to cell surface receptors including the receptor for advanced glycation end products (RAGE). RAGE has proinflammatory roles including in host-pathogen defense, thereby influencing immune cell behavior and can activate and cause proliferation of immune cells such as islet infiltrating CD8+ and CD4+ T cells and suppress the activity of T regulatory cells, contributing to β-cell injury and hyperglycemia. Insights from studies of individuals at risk of T1D have demonstrated that progression to symptomatic onset and diagnosis can vary, ranging from months to years, providing a window of opportunity for prevention strategies. Interaction between AGEs and RAGE is believed to be a major environmental risk factor for T1D and targeting the AGE-RAGE axis may act as a potential therapeutic strategy for T1D prevention.

STAT3 signaling modulates the immune response induced after antigen targeting to conventional type 1 dendritic cells through the DEC205 receptor

Conventional dendritic cells (cDC) are a group of antigen-presenting cells specialized in priming T cell responses. In mice, splenic cDC are divided into conventional type 1 DC (cDC1) and conventional type 2 (cDC2). cDC1 are specialized to prime the Th1 CD4⁺ T cell response, while cDC2 are mainly associated with the induction of follicular helper T cell responses to support germinal center formation. However, the mechanisms that control the functions of cDC1 and cDC2 are not fully understood, especially the signaling pathways that can modulate their ability to promote different CD4⁺ T cell responses. Here, we targeted a model antigen for cDC1 and cDC2, through DEC205 and DCIR2 receptors, respectively, to study the role of the STAT3 signaling pathway in the ability of these cells to prime CD4⁺ T cells. Our results show that, in the absence of the STAT3 signaling pathway, antigen targeting to cDC2 induced similar frequencies of Tfh cells between STAT3-deficient mice compared to fully competent mice. On the other hand, Th1 and Th1-like Tfh cell responses were significantly reduced in STAT3-deficient mice after antigen targeting to cDC1 via the DEC205 receptor. In summary, our results indicate that STAT3 signaling does not control the ability of cDC2 to promote Tfh cell responses after antigen targeting via the DCIR2 receptor, but modulates the function of cDC1 to promote Th1 and Th1-like Tfh T cell responses after antigen targeting via the DEC205 receptor.

Advances in the modulation of ROS and transdermal administration for anti-psoriatic nanotherapies

Reactive oxygen species (ROS) at supraphysiological concentration have a determinate role in contributing to immuno-metabolic disorders in the epithelial immune microenvironment (EIME) of psoriatic lesions. With an exclusive focus on the gene-oxidative stress environment interaction in the EIME, a comprehensive strategy based on ROS-regulating nanomedicines is greatly anticipated to become the mainstay of anti-psoriasis treatment. This potential therapeutic modality could inhibit the acceleration of psoriasis via remodeling the redox equilibrium and reshaping the EIME. Herein, we present a marked overview of the current progress in the pathomechanisms of psoriasis, with particular concerns on the potential pathogenic role of ROS, which significantly dysregulates redox metabolism of keratinocytes (KCs) and skin-resident or -infiltrating cells. Meanwhile, the emergence of versatile nanomaterial-guided evolution for transdermal drug delivery has been attractive for the percutaneous administration of antipsoriatic therapies in recent years. We emphasize the underlying molecular mechanism of ROS-based nanoreactors for improved therapeutic outcomes against psoriasis and summarize up-to-date progress relating to the advantages and limitations of nanotherapeutic application for transdermal administration, as well as update an insight into potential future directions for nanotherapies in ROS-related skin diseases.

Traumatic brain injury alters dendritic cell differentiation and distribution in lymphoid and non-lymphoid organs

Background

Pathophysiological consequences of traumatic brain injury (TBI) mediated secondary injury remain incompletely understood. In particular, the impact of TBI on the differentiation and maintenance of dendritic cells (DCs), which are regarded as the most professional antigen presenting cells of the immune system, remains completely unknown. Here, we report that DC-differentiation, maintenance and functions are altered on day 3 and day 7 after TBI.

Methods

Long bones, spleen, peripheral lymph nodes (pLNs), mesenteric lymph nodes (mLNs), liver, lungs, skin and blood were collected from mice with either moderate-level cortical impact (CCI) or sham on day 1, day 3 or day 7 after TBI. Bone marrow cells were isolated from the tibias and femurs of hind limb through flushing. Tissues were digested with Collagenase-D and DNase I. Skin biopsies were digested in the presence of liberase + DNase I. Single cell suspensions were made, red blood cells were lysed with Ammonium chloride (Stem Cell Technology) and subsequently filtered using a 70 μM nylon mesh. DC subsets of the tissues and DC progenitors of the BM were identified through 10-color flow cytometry-based immunophenotyping studies. Intracellular reactive oxygen species (ROS) were identified through H2DCFDA staining.

Results

Our studies identify that; (1) frequencies and absolute numbers of DCs in the spleen and BM are altered on day 3 and day 7 after TBI; (2) surface expression of key molecules involved in antigen presentation of DCs were affected on day 3 and day 7 after TBI; (3) distribution and functions of tissue-specific DC subsets of both circulatory and lymphatic systems were imbalanced following TBI; (4) early differentiation program of DCs, especially the commitment of hematopoietic stem cells to common DC progenitors (CDPs), were deregulated after TBI; and (5) intracellular ROS levels were reduced in DC progenitors and differentiated DCs on day 3 and day 7 after TBI.

Conclusions

Our data demonstrate, for the first time, that TBI affects the distribution pattern of DCs and induces an imbalance among DC subsets in both lymphoid and non-lymphoid organs. In addition, the current study demonstrates that TBI results in reduced levels of ROS in DCs on day 3 and day 7 after TBI, which may explain altered DC differentiation paradigm following TBI. A deeper understanding on the molecular mechanisms that contribute to DC defects following TBI would be essential and beneficial in treating infections in patients with acute central nervous system (CNS) injuries, such as TBI, stroke and spinal cord injury.

Development of PLGA Nanoparticles with a Glycosylated Myelin Oligodendrocyte Glycoprotein Epitope (MOG35-55) against Experimental Autoimmune Encephalomyelitis (EAE)

Multiple sclerosis (MS) is one of the most common neurodegenerative diseases in young adults, with early clinical symptoms seen in the central nervous system (CNS) myelin sheaths due to an attack caused by the patient's immune system. Activation of the immune system is mediated by the induction of an antigen-specific immune response involving the interaction of multiple T-cell types with antigen-presenting cells (APCs), such as dendritic cells (DCs). Antigen-specific therapeutic approaches focus on immune cells and autoantigens involved in the onset of disease symptoms, which are the main components of myelin proteins. The ability of such therapeutics to bind strongly to DCs could lead to immune system tolerance to the disease. Many modern approaches are based on peptide-based research, as, in recent years, they have been of particular interest in the development of new pharmaceuticals. The characteristics of peptides, such as short lifespan in the body and rapid hydrolysis, can be overcome by their entrapment in nanospheres, providing better pharmacokinetics and bioavailability. The present study describes the development of polymeric nanoparticles with encapsulated myelin peptide analogues involved in the development of MS, along with their biological evaluation as inhibitors of MS development and progression. In particular, particles of poly(lactic-co-glycolic) acid (PLGA) loaded with peptides based on mouse/rat (rMOG) epitope 35-55 of myelin oligodendrocyte glycoprotein (MOG) conjugated with saccharide residues were developed. More specifically, the MOG_35-55 peptide was conjugated with glucosamine to promote the interaction with mannose receptors (MRs) expressed by DCs. In addition, a study of slow release (dissolution) and quantification on both initially encapsulated peptide and daily release in saline in vitro was performed, followed by an evaluation of in vivo activity of the formulation on mouse experimental autoimmune encephalomyelitis (EAE), an animal model of MS, using both prophylactic and therapeutic protocols. Our results showed that the therapeutic protocol was effective in reducing EAE clinical scores and inflammation of the central nervous system and could be an alternative and promising approach against MS inducing tolerance against the disease.

An integrin axis induces IFN-β production in plasmacytoid dendritic cells

Type I interferon (IFN) production by plasmacytoid dendritic cells (pDCs) has been mainly studied in the context of Toll-like receptor (TLR) activation. In the current report, we reveal that, in the absence of TLR activation, the integrin-binding SLAYGLR motif of secreted osteopontin (sOpn) induces IFN-β production in murine pDCs. This process is mediated by α4β1 integrin, indicating that integrin triggering may act as a subtle danger signal leading to IFN-β induction. The SLAYGLR-mediated α4 integrin/IFN-β axis is MyD88 independent and operates via a PI3K/mTOR/IRF3 pathway. Consequently, SLAYGLR-treated pDCs produce increased levels of type I IFNs following TLR stimulation. Intratumoral administration of SLAYGLR induces accumulation of IFN-β-expressing pDCs and efficiently suppresses melanoma tumor growth. In this process, pDCs are crucial. Finally, SLAYGLR enhances pDC development from bone marrow progenitors. These findings open new questions on the roles of sOpn and integrin α4 during homeostasis and inflammation. The newly identified integrin/IFN-β axis may be implicated in a wide array of immune responses.

Dendritic cells drive profibrotic inflammation and aberrant T cell polarization in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a devastating autoimmune disease characterized by fibrosis and obliterative vasculopathy affecting the skin and visceral organs. While the processes mediating excessive extracellular matrix (EM) deposition and fibroblast proliferation are clear, the exact link between autoimmunity and fibrosis remains elusive. Th17 cells have been proposed as critical drivers of profibrotic inflammation during SSc, but little is known about the immune components supporting their pathogenic role.

METHODS

Dendritic cells (DCs) activate and shape T cell differentiation by producing polarizing cytokines. Hence, we investigated the cytokine responses of monocyte-derived DCs (Mo-DCs) from patients with limited cutaneous SSc (lcSSc), diffuse cutaneous SSc (dcSSc), and healthy controls (HC) after stimulation with toll-like receptor (TLR) agonists. Also, using co-culture assays, we analyzed T cell subpopulations after contact with autologous TLR-activated Mo-DCs.

RESULTS

In general, we observed an increased production of Th17 related cytokines like IL-1β, IL-17F, IL-21, IL-22 by SSc compared with HC Mo-DCs, with variations between lcSSc vs. dcSSc and early- vs. late-stage subgroups. Noticeably, we found a significant increment in IL-33 production by Mo-DCs in all SSc cases regardless of their clinical phenotype. Strikingly, T cells displayed Th2, Th17, and dual Th2/Th17 phenotypes after exposure to autologous TLR-stimulated Mo-DCs from SSc patients but not HC. These changes were pronounced in individuals with early-stage dcSSc and less significant in the late-stage lcSSc subgroup.

CONCLUSIONS

Our findings suggest that functional alterations of DCs subsidize the immune mechanisms favoring the aberrant T cell polarization and profibrotic inflammation behind the clinical SSc heterogeneity.

Crosstalk between dendritic cells and T lymphocytes during atherogenesis: Focus on antigen presentation and break of tolerance

Atherosclerosis is a chronic disease resulting from an impaired lipid and immune homeostasis, where the interaction between innate and adaptive immune cells leads to the promotion of atherosclerosis-associated immune-inflammatory response. Emerging evidence has suggested that this response presents similarities to the reactivity of effector immune cells toward self-epitopes, often as a consequence of a break of tolerance. In this context, dendritic cells, a heterogeneous population of antigen presenting cells, play a key role in instructing effector T cells to react against foreign antigens and T regulatory cells to maintain tolerance against self-antigens and/or to patrol for self-reactive effector T cells. Alterations in this delicate balance appears to contribute to atherogenesis. The aim of this review is to discuss different DC subsets, and their role in atherosclerosis as well as in T cell polarization. Moreover, we will discuss how loss of T cell tolerogenic phenotype participates to the immune-inflammatory response associated to atherosclerosis and how a better understanding of these mechanisms might result in designing immunomodulatory therapies targeting DC-T cell crosstalk for the treatment of atherosclerosis-related inflammation.

Class I PI3K regulatory subunits control differentiation of dendritic cell subsets and regulate Flt3L mediated signal transduction

Dendritic cells (DCs) play pivotal roles in initiating and shaping both innate and adaptive immune responses. The spatiotemporal expression of transcription factor networks and activation of specific signal transduction pathways determine the specification, distribution and differentiation of DC subsets. Even though pioneering studies have established indispensable roles for specific catalytic subunits (p110δ and p110γ) in immune cells, functions of the regulatory subunits, particularly of Class I PI3K, within the hematopoietic system remain incompletely understood. In the study presented here, we deleted the key regulatory subunits—p85α and p85β of the Class I_A PI3K in hematopoietic cells and studied its impact on DC differentiation. Our studies identify that a deficiency of p85 causes increased differentiation of conventional DC (cDC) 2 and plasmacytoid DC (pDC) subsets in the spleen. On the other hand, DC numbers in the bone marrow (BM), thymus and lymph nodes were decreased in p85 mutant mice. Analysis of DC-specific progenitors and precursors indicated increased numbers in the BM and spleen of p85 deficient mice. In-vitro differentiation studies demonstrated augmented DC-differentiation capacities of p85 deficient BM cells in the presence of GM-CSF and Flt3L. BM chimera studies established that p85 deficiency affects DC development through cell intrinsic mechanisms. Molecular studies revealed increased proliferation of DCs and common DC progenitors (CDPs) in the absence of p85 and altered signal transduction pathways in p85 mutant DC subsets in response to Flt3L. In essence, data presented here, for the first time, unequivocally establish that the P85α subunit of class I_A PI3Ks has an indispensable role in the development and maintenance of DCs.

siRNA-based nanotherapeutics as emerging modalities for immune-mediated diseases: A preliminary review

Immune‐mediated diseases (IMDs) are chronic conditions that have an immune‐mediated etiology. Clinically, these diseases appear to be unrelated, but pathogenic pathways have been shown to connect them. While inflammation is a common occurrence in the body, it may either stimulate a favorable immune response to protect against harmful signals or cause illness by damaging cells and tissues. Nanomedicine has tremendous promise for regulating inflammation and treating IMIDs. Various nanoparticles coated with nanotherapeutics have been recently fabricated for effective targeted delivery to inflammatory tissues. RNA interference (RNAi) offers a tremendous genetic approach, particularly if traditional treatments are ineffective against IMDs. In cells, several signaling pathways can be suppressed by using RNAi, which blocks the expression of particular messenger RNAs. Using this molecular approach, the undesirable effects of anti‐inflammatory medications can be reduced. Still, there are many problems with using short‐interfering RNAs (siRNAs) to treat IMDs, including poor localization of the siRNAs in target tissues, unstable gene expression, and quick removal from the blood. Nanotherapeutics have been widely used in designing siRNA‐based carriers because of the restricted therapy options for IMIDs. In this review, we have discussed recent trends in the fabrication of siRNA nanodelivery systems, including lipid‐based siRNA nanocarriers, liposomes, and cationic lipids, stable nucleic acid‐lipid particles, polymeric‐based siRNA nanocarriers, polyethylenimine (PEI)‐based nanosystems, chitosan‐based nanoformulations, inorganic material‐based siRNA nanocarriers, and hybrid‐based delivery systems. We have also introduced novel siRNA‐based nanocarriers to control IMIDs, such as pulmonary inflammation, psoriasis, inflammatory bowel disease, ulcerative colitis, rheumatoid arthritis, etc. This study will pave the way for new avenues of research into the diagnosis and treatment of IMDs.

In Situ Tumor Vaccination with Calcium-Linked Degradable Coacervate Nanocomplex Co-Delivering Photosensitizer and TLR7/8 Agonist to Trigger Effective Anti-Tumor Immune Responses

In situ anti-tumor vaccination is an attractive type of cancer immunotherapy which relies on the effectiveness of dendritic cells (DCs) to engulf tumor antigens, become activated, and present antigens to T cells in lymphoid tissue. Here, a multifunctional nanocomplex based on calcium crosslinked polyaspartic acid conjugated to either a toll-like receptor (TLR)7/8 agonist or a photosensitizer is reported. Intratumoral administration of the nanocomplex followed by laser irradiation induces cell killing and hence generation of a pool of tumor-associated antigens, with concomitant promotion of DCs maturation and expansion of T cells in tumor-draining lymph nodes. Suppression of tumor growth is observed both at the primary site and at the distal site, thereby hinting at successful induction of an adaptive anti-tumor response. This strategy holds promise for therapeutic application in a pre-operative and post-operative setting to leverage to mutanome of the patient's own tumor to mount immunological memory to clear residual tumor cells and metastasis.