Recent Advances in Cell Therapeutics for Systemic Autoimmune Diseases

Epigenetic scars in regulatory T cells are retained after successful treatment of chronic hepatitis C with direct-acting antivirals

BACKGROUND & AIMS

Chronic HCV infection results in abnormal immunological alterations, which are not fully normalized after viral elimination by direct-acting antiviral (DAA) treatment. Herein, we longitudinally examined phenotypic, transcriptomic, and epigenetic alterations in peripheral blood regulatory T (Treg) cells from patients with chronic HCV infection before, during, and after DAA treatment.

METHODS

Patients with chronic genotype 1b HCV infection who achieved sustained virologic response by DAA treatment and age-matched healthy donors were recruited. Phenotypic characteristics of Treg cells were investigated through flow cytometry analysis. Moreover, the transcriptomic and epigenetic landscapes of Treg cells were analyzed using RNA sequencing and ATAC-seq (assay for transposase-accessible chromatin with sequencing) analysis.

RESULTS

The Treg cell population - especially the activated Treg cell subpopulation - was expanded in peripheral blood during chronic HCV infection, and this expansion was sustained even after viral clearance. RNA sequencing analysis revealed that viral clearance did not abrogate the inflammatory features of these Treg cells, such as Treg activation and TNF signaling. Moreover, ATAC-seq analysis showed inflammatory imprinting in the epigenetic landscape of Treg cells from patients, which remained after treatment. These findings were further confirmed by intracellular cytokine staining, demonstrating that Treg cells exhibited inflammatory features and TNF production in chronic HCV infection that were maintained after viral clearance.

CONCLUSIONS

Overall, our results showed that during chronic HCV infection, the expanded Treg cell population acquired inflammatory features at phenotypic, transcriptomic, and epigenetic levels, which were maintained even after successful viral elimination by DAA treatment. Further studies are warranted to examine the clinical significance of sustained inflammatory features in the Treg cell population after recovery from chronic HCV infection.

IMPACT AND IMPLICATIONS

During chronic HCV infection, several immune components are altered both quantitatively and qualitatively. The recent introduction of direct-acting antivirals has led to high cure rates. Nevertheless, we have demonstrated that inflammatory features of Treg cells are maintained at phenotypic, transcriptomic, and epigenetic levels even after successful DAA treatment. Further in-depth studies are required to investigate the long-term clinical outcomes of patients who have recovered from chronic HCV infection.

Comprehensive insights into rheumatoid arthritis: Pathophysiology, current therapies and herbal alternatives for effective disease management

Rheumatoid arthritis is a chronic autoimmune inflammatory disease characterized by immune response overexpression, causing pain and swelling in the synovial joints. This condition is caused by auto-reactive antibodies that attack self-antigens due to their incapacity to distinguish between self and foreign molecules. Dysregulated activity within numerous signalling and immunological pathways supports the disease's development and progression, elevating its complexity. While current treatments provide some alleviation, their effectiveness is accompanied by a variety of adverse effects that are inherent in conventional medications. As a result, there is a deep-rooted necessity to investigate alternate therapeutic strategies capable of neutralizing these disadvantages. Medicinal herbs display a variety of potent bioactive phytochemicals that are effective in the complementary management of disease, thus generating an enormous potency for the researchers to delve deep into the development of novel phytomedicine against autoimmune diseases, although additional evidence and understanding are required in terms of their efficacy and pharmacodynamic mechanisms. This literature-based review highlights the dysregulation of immune tolerance in rheumatoid arthritis, analyses the pathophysiology, elucidates relevant signalling pathways involved, evaluates present and future therapy options and underscores the therapeutic attributes of a diverse array of medicinal herbs in addressing this severe disease.

A new perspective on therapies involving B-cell depletion in autoimmune diseases

It has been rediscovered in the last fifteen years that B-cells play an active role in autoimmune etiology rather than just being spectators. The clinical success of B-cell depletion therapies (BCDTs) has contributed to this. BCDTs, including those that target CD20, CD19, and BAFF, were first developed to eradicate malignant B-cells. These days, they treat autoimmune conditions like multiple sclerosis and systemic lupus erythematosus. Particular surprises have resulted from the use of BCDTs in autoimmune diseases. For example, even in cases where BCDT is used to treat the condition, its effects on antibody-secreting plasma cells and antibody levels are restricted, even though these cells are regarded to play a detrimental pathogenic role in autoimmune diseases. In this Review, we provide an update on our knowledge of the biology of B-cells, examine the outcomes of clinical studies employing BCDT for autoimmune reasons, talk about potential explanations for the drug's mode of action, and make predictions about future approaches to targeting B-cells other than depletion.

IL-17 and IL-21: Their Immunobiology and Therapeutic Potentials

Studies over the last 2 decades have identified IL-17 and IL-21 as key cytokines in the modulation of a wide range of immune responses. IL-17 serves as a critical defender against bacterial and fungal pathogens, while maintaining symbiotic relationships with commensal microbiota. However, alterations in its levels can lead to chronic inflammation and autoimmunity. IL-21, on the other hand, bridges the adaptive and innate immune responses, and its imbalance is implicated in autoimmune diseases and cancer, highlighting its important role in both health and disease. Delving into the intricacies of these cytokines not only opens new avenues for understanding the immune system, but also promises innovative advances in the development of therapeutic strategies for numerous diseases. In this review, we will discuss an updated view of the immunobiology and therapeutic potential of IL-17 and IL-21.

Promising Therapeutic Effects of Embryonic Stem Cells-Origin Mesenchymal Stem Cells in Experimental Pulmonary Fibrosis Models: Immunomodulatory and Anti-Apoptotic Mechanisms

Interstitial lung disease (ILD) involves persistent inflammation and fibrosis, leading to respiratory failure and even death. Adult tissue-derived mesenchymal stem cells (MSCs) show potential in ILD therapeutics but obtaining an adequate quantity of cells for drug application is difficult. Daewoong Pharmaceutical's MSCs (DW-MSCs) derived from embryonic stem cells sustain a high proliferative capacity following long-term culture and expansion. The aim of this study was to investigate the therapeutic potential of DW-MSCs in experimental mouse models of ILD. DW-MSCs were expanded up to 12 passages for in vivo application in bleomycin-induced pulmonary fibrosis and collagen-induced connective tissue disease-ILD mouse models. We assessed lung inflammation and fibrosis, lung tissue immune cells, fibrosis-related gene/protein expression, apoptosis and mitochondrial function of alveolar epithelial cells, and mitochondrial transfer ability. Intravenous administration of DW-MSCs consistently improved lung fibrosis and reduced inflammatory and fibrotic markers expression in both models across various disease stages. The therapeutic effect of DW-MSCs was comparable to that following daily oral administration of nintedanib or pirfenidone. Mechanistically, DW-MSCs exhibited immunomodulatory effects by reducing the number of B cells during the early phase and increasing the ratio of Tregs to Th17 cells during the late phase of bleomycin-induced pulmonary fibrosis. Furthermore, DW-MSCs exhibited anti-apoptotic effects, increased cell viability, and improved mitochondrial respiration in alveolar epithelial cells by transferring their mitochondria to alveolar epithelial cells. Our findings indicate the strong potential of DW-MSCs in the treatment of ILD owing to their high efficacy and immunomodulatory and anti-apoptotic effects.

Mesenchymal Stem/Stromal Cell-Based Therapies in Systemic Rheumatic Disease: From Challenges to New Approaches for Overcoming Restrictions

Systemic rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, are chronic autoimmune diseases affecting multiple organs and tissues. Despite recent advances in treatment, patients still experience significant morbidity and disability. Mesenchymal stem/stromal cell (MSC)-based therapy is promising for treating systemic rheumatic diseases due to the regenerative and immunomodulatory properties of MSCs. However, several challenges need to be overcome to use MSCs in clinical practice effectively. These challenges include MSC sourcing, characterization, standardization, safety, and efficacy issues. In this review, we provide an overview of the current state of MSC-based therapies in systemic rheumatic diseases, highlighting the challenges and limitations associated with their use. We also discuss emerging strategies and novel approaches that can help overcome the limitations. Finally, we provide insights into the future directions of MSC-based therapies for systemic rheumatic diseases and their potential clinical applications.

Research progress of engineered mesenchymal stem cells and their derived exosomes and their application in autoimmune/inflammatory diseases

Autoimmune/inflammatory diseases affect many people and are an important cause of global incidence and mortality. Mesenchymal stem cells (MSCs) have low immunogenicity, immune regulation, multidifferentiation and other biological characteristics, play an important role in tissue repair and immune regulation and are widely used in the research and treatment of autoimmune/inflammatory diseases. In addition, MSCs can secrete extracellular vesicles with lipid bilayer structures under resting or activated conditions, including exosomes, microparticles and apoptotic bodies. Among them, exosomes, as the most important component of extracellular vesicles, can function as parent MSCs. Although MSCs and their exosomes have the characteristics of immune regulation and homing, engineering these cells or vesicles through various technical means, such as genetic engineering, surface modification and tissue engineering, can further improve their homing and other congenital characteristics, make them specifically target specific tissues or organs, and improve their therapeutic effect. This article reviews the advanced technology of engineering MSCs or MSC-derived exosomes and its application in some autoimmune/inflammatory diseases by searching the literature published in recent years at home and abroad.

Myeloidderived suppressor cells: Escorts at the maternal-fetal interface

Myeloid-derived suppressor cells (MDSCs) are a novel heterogenous group of immunosuppressive cells derived from myeloid progenitors. Their role is well known in tumors and autoimmune diseases. In recent years, the role and function of MDSCs during reproduction have attracted increasing attention. Improving the understanding of their strong association with recurrent implantation failure, pathological pregnancy, and neonatal health has become a focus area in research. In this review, we focus on the interaction between MDSCs and other cell types (immune and non-immune cells) from embryo implantation to postpartum. Furthermore, we discuss the molecular mechanisms that could facilitate the therapeutic targeting of MDSCs. Therefore, this review intends to encourage further research in the field of maternal-fetal interface immunity in order to identify probable pathways driving the accumulation of MDSCs and to effectively target their ability to promote embryo implantation, reduce pathological pregnancy, and increase neonatal health.

An In Vivo Mouse Model for Chronic Inflammation-Induced Immune Suppression: A "Factory" for Myeloid-Derived Suppressor Cells (MDSCs)

Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells known to play a role in perpetuating a wide range of pathologies, such as chronic infections, autoimmune diseases, and cancer. MDSCs were first identified in mice by the markers CD11b+ Gr1+ , and later, based on their morphology, they were classified into two subsets: polymorphonuclear MDSCs, identified by the markers CD11b+ Ly6G+ Ly6CLow , and monocytic MDSCs, detected as being CD11b+ Ly6G- Ly6CHi . MDSCs are studied as immunosuppressive cells in various diseases characterized by chronic inflammation and are associated with disease causes/triggers such as pathogens, autoantigens, and cancer. Therefore, different diseases may diversely affect MDSC metabolism, migration, and differentiation, thus influencing the generated MDSC functional features and ensuing suppressive environment. In order to study MDSCs in a pathology-free environment, we established and calibrated a highly reproducible mouse model that results in the development of chronic inflammation, which is the major cause of MDSC accumulation and immune suppression. The model presented can be used to study MDSC phenotypes, functional diversity, and plasticity. It also permits study of MDSC migration from the bone marrow to peripheral lymphatic and non-lymphatic organs and MDSC crosstalk with extrinsic factors, both in vivo and ex vivo. Furthermore, this model can serve as a platform to assess the effects of anti-MDSC modalities. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Repetitive M.tb immunizations for the induction of chronic inflammation Alternate Protocol 1: Creating a lower grade of inflammation by changing the site of immunization Alternate Protocol 2: In vivo evaluation of immune status Support Protocol 1: Preparation of reconstituted M.tb aliquots and M.tb-IFA emulsions for each of the three injections Support Protocol 2: Preparation of an ovalbumin lentiviral expression vector Support Protocol 3: Fluorescence titering assay for the lentiviral expression vector Support Protocol 4: Spleen excision, tissue dissociation, and preparation of a single-cell suspension Support Protocol 5: Labeling of splenocytes with CFSE proliferation dye.