Regulatory T cell therapy for multiple sclerosis: Breaching (blood-brain) barriers

Multiple sclerosis treatments a review of current biomedical engineering approaches

Multiple Sclerosis (MS) is an autoimmune condition targeting the central nervous system (CNS) characterized by focal demyelination with inflammation, causing neurodegeneration and gliosis. This is accompanied by a refractory period in relapsing MS or chronic progression in primary progressive MS. Current MS treatments target disease relapses and aim to reduce further demyelination and disability. These include the treatment of acute exacerbations through global immunomodulation upon corticosteroid administration, which are accompanied by adverse reactions. Disease modifying therapies (DMTs) which provide targeted immunosuppression of T and B cells, and sequestration of leukocytes out of CNS, have led to further improvements in demyelination prevention and disease burden reduction. Despite their efficacy, DMTs are ineffective in remyelination, pathology reversal and have minimal effects in progressive MS. The advent of modern biomedical engineering approaches in combination with a better understanding of MS pathology, has led to the development of novel, regenerative approaches to treatment. Such treatments utilize neural stem cells (NSCs) and can reduce disease relapses and reverse damage caused by the disease through localized tissue regeneration. While at initial stages, pre-clinical and clinical studies utilizing NSCs and immune modulation have shown promising outcomes in tissue regeneration, creating a potential new era in MS therapy.

Flow cytometry identifies changes in peripheral and intrathecal lymphocyte patterns in CNS autoimmune disorders and primary CNS malignancies

BACKGROUND

Immune dysregulation is a hallmark of autoimmune diseases of the central nervous system (CNS), characterized by an excessive immune response, and primary CNS tumors (pCNS-tumors) showing a highly immunosuppressive parenchymal microenvironment.

METHODS

Aiming to provide novel insights into the pathogenesis of CNS autoimmunity and cerebral tumor immunity, we analyzed the peripheral blood (PB) and cerebrospinal fluid (CSF) of 81 autoimmune limbic encephalitis (ALE), 148 relapsing-remitting multiple sclerosis (RRMS), 33 IDH-wildtype glioma, 9 primary diffuse large B cell lymphoma of the CNS (CNS-DLBCL), and 110 controls by flow cytometry (FC). Additionally, an in-depth immunophenotyping of the PB from an independent cohort of 20 RRMS and 18 IDH-wildtype glioblastoma patients compared to 19 controls was performed by FC combined with unsupervised computational approaches.

RESULTS

We identified alterations in peripheral and intrathecal adaptive immunity, mainly affecting the T cell (Tc) but also the B cell (Bc) compartment in ALE, RRMS, and pCNS-tumors compared to controls. ALE, RRMS, and pCNS-tumors featured higher expression of the T cell activation marker HLA-DR, which was even more pronounced in pCNS-tumors than in ALE or RRMS. Glioblastoma patients showed signs of T cell exhaustion that were not visible in RRMS patients. In-depth characterization of the PB revealed differences mainly in the T effector and memory compartment between RRMS and glioblastoma patients and similar alterations in the Bc compartment, including atypical Bc, CD19+CD20- double negative Bc, and plasma cells. PB and CSF mFC together with CSF routine parameters could reliably differentiate ALE and RRMS from pCNS-tumors facilitating early diagnosis and treatment.

CONCLUSIONS

ALE, RRMS, and pCNS-tumors show distinct but partially overlapping changes mainly in HLA-DR+ Tc, memory Tc, exhausted Tc, and Bc subsets providing insights into disease pathogenesis. Moreover, mFC shows diagnostic potential facilitating early diagnosis and treatment.

Schistosoma antigens: A future clinical magic bullet for autoimmune diseases?

Autoimmune diseases are characterized by dysregulated immunity against self-antigens. Current treatment of autoimmune diseases largely relies on suppressing host immunity to prevent excessive inflammation. Other immunotherapy options, such as cytokine or cell-targeted therapies, have also been used. However, most patients do not benefit from these therapies as recurrence of the disease usually occurs. Therefore, more effort is needed to find alternative immune therapeutics. Schistosoma infection has been a significant public health problem in most developing countries. Schistosoma parasites produce eggs that continuously secrete soluble egg antigen (SEA), which is a known modulator of host immune responses by enhancing Th2 immunity and alleviating outcomes of Th1 and Th17 responses. Recently, SEA has shown promise in treating autoimmune disorders due to their substantial immune-regulatory effects. Despite this interest, how these antigens modulate human immunity demonstrates only limited pieces of evidence, and whether there is potential for Schistosoma antigens in other diseases in the future remains an unsolved question. This review discusses how SEA modulates human immune responses and its potential for development as a novel immunotherapeutic for autoimmune diseases. We also discuss the immune modulatory effects of other non-SEA schistosome antigens at different stages of the parasite's life cycle.

MOG-specific CAR Tregs: a novel approach to treat multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS) with the immune system attacking myelin sheaths leading to neuronal death. While several disease-modifying therapies are available to treat MS, these therapies are not universally effective and do not stop disease progression. More personalized long-term treatment options that target specific aspects of the disease, such as reducing relapse frequency, delaying disability accumulation, and addressing symptoms that impact daily functioning, as well as therapies that can promote neuroprotection and repair are needed. Chimeric Antigen Receptor (CAR) Tcell therapies have revolutionized cancer treatment by intravenously (IV) administering a defined dose of T cells with high specificity provided by the CAR. An autologous CAR T cell therapy using suppressive regulatory T cells (Tregs) inducing long-lasting tolerance would be the ideal treatment for patients. Hence, we expanded the application of CAR-T cells by introducing a CAR into Tregs to treat MS patients. We developed a myelin oligodendrocyte glycoprotein (MOG)-specific CAR Treg cell therapy for patients with MS. MOG is expressed on the outer membrane of the myelin sheath, the insulating layer the forms around nerves, making it an ideal target for CAR Treg therapy. Our lead candidate is a 2nd generation CAR, composed of an anti-MOG scFv screened from a large human library. In vitro, we demonstrated CAR-dependent functionality and showed efficacy in vivo using a passive EAE mouse model. Additionally, the MOG-CAR Tregs have very low tonic signaling with a desirable signal-to-noise ratio resulting in a highly potent CAR. In summary our data suggest that MOG-CAR Tregs are a promising MS treatment option with the potential to induce long-lasting tolerance in patients.

Low-dose IL-2 therapy in autoimmune diseases: An update review

Regulatory T (Treg) cells are essential for maintaining self-immune tolerance. Reduced numbers or functions of Treg cells have been involved in the pathogenesis of various autoimmune diseases and allograft rejection. Therefore, the approaches that increase the pool or suppressive function of Treg cells in vivo could be a general strategy to treat different autoimmune diseases and allograft rejection. Interleukin-2 (IL-2) is essential for the development, survival, maintenance, and function of Treg cells, constitutively expressing the high-affinity receptor of IL-2 and sensitive response to IL-2 in vivo. And low-dose IL-2 therapy in vivo could restore the imbalance between autoimmune response and self-tolerance toward self-tolerance via promoting Treg cell expansion and inhibiting follicular helper T (Tfh) and IL-17-producing helper T (Th17) cell differentiation. Currently, low-dose IL-2 treatment is receiving extensive attention in autoimmune disease and transplantation treatment. In this review, we summarize the biology of IL-2/IL-2 receptor, the mechanisms of low-dose IL-2 therapy in autoimmune diseases, the application in the progress of different autoimmune diseases, including Systemic Lupus Erythematosus (SLE), Type 1 Diabetes (T1D), Rheumatoid Arthritis (RA), Autoimmune Hepatitis (AIH), Alopecia Areata (AA), Immune Thrombocytopenia (ITP) and Chronic graft-versus-host-disease (GVHD). We also discuss the future directions to optimize low-dose IL-2 treatments.

Regulatory role of PI16 in autoimmune arthritis and intestinal inflammation: implications for Treg cell differentiation and function

BACKGROUND

Regulatory T cells (Tregs) are crucial in maintaining immune homeostasis and preventing autoimmunity and inflammation. A proportion of Treg cells can lose Foxp3 expression and become unstable under inflammation conditions. The precise mechanisms underlying this phenomenon remain unclear.

METHODS

The PI16 gene knockout mice (PI16fl/flFoxp3Cre) in Treg were constructed, and the genotypes were identified. The proportion and phenotypic differences of immune cells in 8-week-old mice were detected by cell counter and flow cytometry. Two groups of mouse Naïve CD4+T cells were induced to differentiate into iTreg cells to observe the effect of PI16 on the differentiation and proliferation of iTreg cells, CD4+CD25+Treg and CD4+CD25- effector T cells (Teff) were selected and co-cultured with antigen presenting cells (APC) to observe the effect of PI16 on the inhibitory ability of Treg cells in vitro. The effects of directed knockout of PI16 in Treg cells on inflammatory symptoms, histopathological changes and immune cell expression in mice with enteritis and autoimmune arthritis were observed by constructing the model of antigen-induced arthritis (AIA) and colitis induced by dextran sulfate sodium salt (DSS).

RESULTS

We identified peptidase inhibitor 16 (PI16) as a negative regulator of Treg cells. Our findings demonstrate that conditional knock-out of PI16 in Tregs significantly enhances their differentiation and suppressive functions. The conditional knockout of the PI16 gene resulted in a significantly higher abundance of Foxp3 expression (35.12 ± 5.71% vs. 20.00 ± 1.61%, p = 0.034) in iTreg cells induced in vitro compared to wild-type mice. Mice with Treg cell-specific PI16 ablation are protected from autoimmune arthritis (AIA) and dextran sulfate sodium (DSS)-induced colitis development. The AIA model of PI16CKO is characterized by the reduction of joint structure and the attenuation of synovial inflammation and in DSS-induced colitis model, conditional knockout of the PI16 reduce intestinal structural damage. Additionally, we found that the deletion of the PI16 gene in Treg can increase the proportion of Treg (1.46 ± 0.14% vs. 0.64 ± 0.07%, p < 0.0001) and decrease the proportion of Th17 (1.00 ± 0.12% vs. 3.84 ± 0.64%, p = 0.001). This change will enhance the shift of Th17/Treg toward Treg cells in AIA arthritis model (0.71 ± 0.06% vs. 8.07 ± 1.98%, p = 0.003). In DSS-induced colitis model of PI16CKO, the proportion of Treg in spleen was significantly increased (1.40 ± 0.15% vs. 0.50 ± 0.11%, p = 0.003), Th17 (2.18 ± 0.55% vs. 6.42 ± 1.47%, p = 0.017), Th1 (3.42 ± 0.19% vs. 6.59 ± 1.28%, p = 0.028) and Th2 (1.52 ± 0.27% vs. 2.76 ± 0.38%, p = 0.018) in spleen was significantly decreased and the Th17/Treg balance swift toward Treg cells (1.44 ± 0.50% vs. 24.09 ± 7.18%, p = 0.012).

CONCLUSION

PI16 plays an essential role in inhibiting Treg cell differentiation and function. Conditional knock out PI16 gene in Treg can promote the Treg/Th17 balance towards Treg dominance, thereby alleviating the condition. Targeting PI16 may facilitate Treg cell-based therapies for preventing autoimmune diseases and inflammatory diseases. The research provides us with novel insights and future research avenues for the treatment of autoimmune diseases, particularly arthritis and colitis.

Calcitriol restrains microglial M1 polarization and alleviates dopaminergic degeneration in hemiparkinsonian mice by boosting regulatory T-cell expansion

OBJECTIVE

Vitamin D deficiency is a risk factor for Parkinson's disease (PD) and vitamin D supplementation robustly alleviates neurodegeneration in PD models. However, the mechanisms underlying this effect require further clarification. Current evidence suggests that harnessing regulatory T cells (Treg) may mitigate neuronal degeneration. In this study, we investigated the therapeutic effects of vitamin D receptor activation by calcitriol on PD, specifically focusing on its role in Treg.

METHODS

Hemiparkinsonian mice model was established through the injection of 6-OHDA into the striatum. Mice were pretreated with calcitriol before 6-OHDA injection. The motor performance, dopaminergic neuronal survival, contents of dopamine, and dopamine metabolites were evaluated. The pro-inflammatory cytokines levels, T-cell infiltration, mRNA expression of indicated microglial M1/M2 phenotypic markers, and microglial marker in the midbrain were detected. Populations of Treg in the splenic tissues were assessed using a flow cytometry assay. PC61 monoclonal antibody was applied to deplete Treg in vivo.

RESULTS

We show that calcitriol supplementation notably improved motor performance and reduced dopaminergic degeneration in the 6-OHDA-induced PD model. Mechanistically, calcitriol promoted anti-inflammatory/neuroprotective Treg and inhibited pro-inflammatory/neurodestructive effector T-cell generation in this model. This process significantly inhibited T-cell infiltration in the midbrain, restrained microglial activation, microglial M1 polarization, and decreased pro-inflammatory cytokines release. This more favorable inflammatory microenvironment rescued dopaminergic degeneration. To further verify that the anti-inflammatory effects of calcitriol are associated with Treg expansion, we applied an antibody-mediated Treg depletion assay. As predicted, the anti-inflammatory effects of calcitriol in the PD model were diminished following Treg depletion.

CONCLUSION

These findings suggest that calcitriol's anti-inflammatory and neuroprotective effects in PD are associated with its potential to boost Treg expansion.

Engineered CAR-T cells: An immunotherapeutic approach for cancer treatment and beyond

Chimeric Antigen Receptor (CAR) T cell therapy is a type of adoptive immunotherapy that offers a promising avenue for enhancing cancer treatment since traditional cancer treatments like chemotherapy, surgery, and radiation therapy have proven insufficient in completely eradicating tumors, despite the relatively positive outcomes. It has been observed that CAR-T cell therapy has shown promising results in treating the majority of hematological malignancies but also have a wide scope for other cancer types. CAR is an extra receptor on the T-cell that helps to increase and accelerate tumor destruction by efficiently activating the immune system. It is made up of three domains, the ectodomain, transmembrane, and the endodomain. The ectodomain is essential for antigen recognition and binding, whereas the co-stimulatory signal is transduced by the endodomain. To date, the Food and Drug Administration (FDA) has granted approval for six CAR-T cell therapies. However, despite its remarkable success, CAR-T therapy is associated with numerous adverse events and has certain limitations. This chapter focuses on the structure and function of the CAR domain, various generations of CAR, and the process of CAR-T cell development, adverse effects, and challenges in CAR-T therapy. CAR-T cell therapy also has scopes in other disease conditions which include systemic lupus erythematosus, multiple sclerosis, and myocardial fibrosis, etc.

Regulatory T Cells in Multiple Sclerosis Diagnostics-What Do We Know So Far?

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disorder that affects the central nervous system (CNS) through inflammation. MS symptoms become acute if the disease progresses to the relapsing phase.

AIM

This review aimed to evaluate the role played by regulatory T cells (Tregs) in the pathogenesis of MS.

METHODS

This review used scholarly journal articles obtained from PubMed, PsycINFO, and CINAHL with different search parameters such as 'regulatory T cells', 'multiple sclerosis', and 'current knowledge'. The process of searching for articles was limited to those that had publication dates falling between 2010 and 2020.

RESULTS

Tregs play a role in the pathogenesis of MS. This conclusion is supported by animal disease models and environmental factors that can underlie Treg alterations in MS. Despite the knowledge of the role played by Tregs in MS pathogenesis, the specific subsets of Tregs involved in MS development remain incompletely understood.

DISCUSSION

This review provides an essential link between Tregs and MS activity. Targeting Tregs could be an efficient way to establish new treatment methods for MS management.

CONCLUSION

MS is a complex condition affecting many people worldwide. Research has shown that Tregs can influence MS development and progression. More investigations are needed to understand how Tregs affect the pathogenesis of MS.

Differential roles of regulatory T cells in Alzheimer's disease

Regulatory T (Treg) cells interact with a variety of resident cells and infiltrated immune cells in the central nervous system (CNS) to modulate neuroinflammation and neurodegeneration. Extracellular amyloid-β (Aβ) peptide deposition and secondary persistent inflammation due to activation of microglia, astrocytes, and infiltrated immune cells contribute to Alzheimer's disease (AD)-related neurodegeneration. The majority of evidence supports the neuroprotective effects of Treg cells in AD. In the early stages of AD, appropriate Treg cell activity is required for the induction of microglia and astrocyte phagocytic activity in order to clear A deposits and prevent neuroinflammation. Such neuroprotective impacts were in part attributed to the ability of Treg cells to suppress deleterious and/or boost beneficial functions of microglia/astrocytes. In the later stages of AD, an effective Treg cell activity needs to prevent neurotoxicity and neurodegeneration. Treg cells can exert preventive effects on Th1-, and Th17 cell-related pathologic responses, whilst potentiating Th2-mediated protective activity. The impaired Treg cell-related immunomodulatory mechanisms have been described in AD patients and in related animal models which can contribute to the onset and progression of AD. This review aimed to provide a comprehensive figure regarding the role of Treg cells in AD while highlighting potential therapeutic approaches.