Natural killer receptors distribution in multiple sclerosis: Relation to clinical course and interferon-beta therapy

A computational approach based on weighted gene co-expression network analysis for biomarkers analysis of Parkinson's disease and construction of diagnostic model

Background

Parkinson's disease (PD) is a common age-related chronic neurodegenerative disease. There is currently no affordable, effective, and less invasive test for PD diagnosis. Metabolite profiling in blood and blood-based gene transcripts is thought to be an ideal method for diagnosing PD.

Aim

In this study, the objective is to identify the potential diagnostic biomarkers of PD by analyzing microarray gene expression data of samples from PD patients.

Methods

A computational approach, namely, Weighted Gene Co-expression Network Analysis (WGCNA) was used to construct co-expression gene networks and identify the key modules that were highly correlated with PD from the GSE99039 dataset. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was performed to identify the hub genes in the key modules with strong association with PD. The selected hub genes were then used to construct a diagnostic model based on logistic regression analysis, and the Receiver Operating Characteristic (ROC) curves were used to evaluate the efficacy of the model using the GSE99039 dataset. Finally, Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to validate the hub genes.

Results

WGCNA identified two key modules associated with inflammation and immune response. Seven hub genes, LILRB1, LSP1, SIPA1, SLC15A3, MBOAT7, RNF24, and TLE3 were identified from the two modules and used to construct diagnostic models. ROC analysis showed that the diagnostic model had a good diagnostic performance for PD in the training and testing datasets. Results of the RT-PCR experiments showed that there were significant differences in the mRNA expression of LILRB1, LSP1, and MBOAT7 among the seven hub genes.

Conclusion

The 7-gene panel (LILRB1, LSP1, SIPA1, SLC15A3, MBOAT7, RNF24, and TLE3) will serve as a potential diagnostic signature for PD.

The role of NK and NKT cells in the pathogenesis and improvement of multiple sclerosis following disease-modifying therapies

BACKGROUND

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS) that T cells become autoreactive by recognizing CNS antigens. Both innate and adaptive immune systems are involved in the pathogenesis of MS. In recent years, the impact of innate immune cells on MS pathogenesis has received more attention. CD56bright NK cells, as an immunoregulatory subset of NK cells, can increase the production of cytokines that modulate adaptive immune responses, whereas CD56dim NK cells are more active in cytolysis functions. These two main subsets of NK cells may have different effects on the onset or progression of MS. Invariant NKT (iNKT) cells are other immune cells involved in the control of autoimmune diseases; however, variant NKT (vNKT) cells, despite limited information, could play a role in MS remission via an immunoregulatory pathway.

AIM

We aimed to evaluate the influence of MS therapeutic agents on NK and NKT cells and NK cell subtypes.

MATERIALS AND METHODS

The possible mechanism of each MS therapeutic agent has been presented here, focusing on the effects of different disease-modifying therapies on the number of NK and NKT subtypes.

RESULTS

Expansion of CD56bright NK cells, reduction in the CD56dim cells, and enhancement in NKT cells are the more important innate immune cells alterations following the disease-modifying therapies.

CONCLUSION

Expansion of CD56bright NK cells or reduction in the CD56dim cells has been associated with a successful response to different treatments in MS. iNKT and vNKT cells could have beneficial effects on MS improving. It seems that they are enhanced due to some of MS drugs, leading to disease improvement. However, a reduction in the number of NKT cells could be due to the adverse effects of some of MS drugs on the bone marrow.

An immunological and transcriptomics approach on differential modulation of NK cells in multiple sclerosis patients under interferon-β1 and fingolimod therapy

This study aims to compare NK cells obtained from multiple sclerosis (MS) patients receiving interferon-β1 and fingolimod therapies. Fingolimod reduced the CD56^bright NK cell subset. The remaining CD56^dim NK cells displayed NKG2D, NKp46, CD107a, and IFN-γ levels similar to those from the patients under interferon-β1 therapy. Alternatively, comparative transcriptomics and pathway analyses revealed significant distinctions between two therapy modalities. Molecular signature of the CD56^dim NK cells from fingolimod-treated MS patients was closely associated to those from healthy subjects. The basic assets of NK cells were modestly influenced by interferon-β1 and fingolimod, however transcriptomics showed profound alterations in NK responses.

Identification of Monotonically Differentially Expressed Genes for IFN-β-Treated Multiple Sclerosis Patients

Multiple sclerosis (MS) is a common neurological disability of the central nervous system. Immune-modulatory therapy with interferon-β (IFN-β) has been used as a first-line treatment to prevent relapses in MS patients. While the therapeutic mechanism of IFN-β has not been fully elucidated, the data of microarray experiments that collected longitudinal gene expression profiles to evaluate the long-term response of IFN-β treatment have been analyzed using statistical methods that were incapable of dealing with such data. In this study, the GeneRank method was applied to generate weighted gene expression values and the monotonically expressed genes (MEGs) for both IFN-β treatment responders and nonresponders were identified. The proposed procedure identified 13 MEGs for the responders and 2 MEGs for the nonresponders, most of which are biologically relevant to MS. Our work here provides some useful insight into the mechanism of IFN-β treatment for MS patients. A full understanding of the therapeutic mechanism will enable a more personalized treatment strategy possible.

Flip-flops of natural killer cells in autoimmune diseases versus cancers: Immunologic axis

Natural killer (NK) cells play an essential role in the immune response to infections, inflammations, and malignancies. Recent studies suggest that NK cell surface receptors and cytokines are the key points of the disease development and protection. We hypothesized that the interactions between NK cell receptors and targeted cells construct an eventual niche, and this niche has an eventual profile in various autoimmune diseases and cancers. The NK cells preactivated with cytokines, such as interleukin-2 (IL-2), IL-12, IL-15, and IL-18 can have higher cytotoxicity; however, the toxic side effect of IL-2 should be considered. The vicissitudes of NK cell profile and its receptors obey the environmental communications and cell interactions. Our vision around the NK cells as an immune axis remained dual, and we still cannot judge the immune responses based on the NK cell flip-flop. A design of eventual niche to monitor the NK cell and targeted cell interaction is needed to strengthen our ability in diagnosis and treatment approaches based on the NK cells. Here, we have reviewed the shifts in the NK cells and their surface receptors in autoimmune diseases, solid tumors, and leukemia, and also discussed the effective chemokines that affect NK cell activation and proliferation. The main aim of this review is to present a broader vision of the NK cell changes in autoimmune disease and cancers.

Natural killer cell subpopulations are associated with MRI activity in a relapsing-remitting multiple sclerosis patient cohort from Australia

Background:

The importance of the innate immune system in multiple sclerosis (MS) is increasingly recognized and the role of natural killer (NK) cells in controlling autoimmunity may be an important modulator of disease activity.

Objective:

To examine NK subsets in MS patients on different treatments and to evaluate the role of NK subsets as indicators for disease activity.

Methods:

We measured NK subset levels in blood obtained from 110 relapsing-remitting MS patients. Patients were either off treatment or on treatment with natalizumab, fingolimod, glatiramer acetate or beta-interferon. Disease activity was defined according to ‘No Evidence of Disease Activity’ (NEDA) criteria within an observation period of up to 2.4 years. The mean NK subset levels were compared among treatment groups using multivariate analysis of variance (ANOVA) and association analysis with disease activity performed using multi-factor logistic regression.

Results:

Our analysis revealed differences in NK cells and subsets on treatment compared to off treatment ( p < 0.0005). A high proportion of bright NK cells were significantly associated with stable magnetic resonance imaging (MRI) imaging after adjusting for treatment effects ( p < 0.05).

Conclusion:

The independent association of NK subsets with MRI stability needs to be confirmed in prospective studies to test their usefulness in predicting disease activity in MS patients.

Latent Cytomegalovirus Infection in Rheumatoid Arthritis and Increased Frequencies of Cytolytic LIR-1+CD8+ T Cells

Objective

Leukocyte immunoglobulin‐like receptor 1 (LIR‐1) is up‐regulated by cytomegalovirus (CMV), which in turn, has been associated with premature aging and more severe joint disease in patients with rheumatoid arthritis (RA). The aim of this study was to investigate the expression and functional significance of LIR‐1 in CMV‐positive RA patients.

Methods

We determined the phenotype, cytolytic potential, CMV‐specific proliferation, and HLA–G–triggered, LIR‐1–mediated inhibition of interferon‐γ secretion of LIR‐1+ T cells in RA patients and healthy controls.

Results

We found increased frequencies of CD8+ T cells with CMV pp65–specific T cell receptors in CMV‐positive RA patients as compared to CMV‐positive healthy controls. CMV‐specific CD8+ T cells in these patients were preferentially LIR‐1+ and exhibited a terminally differentiated polyfunctional phenotype. The numbers of LIR‐1+CD8+ T cells increased with age and disease activity, and showed high levels of reactivity to CMV antigens. Ligation of LIR‐1 with soluble HLA–G molecules in vitro confirmed an inhibitory role of the molecule when expressed on CD8+ T cells in RA patients.

Conclusion

We propose that latent CMV infection in the context of a chronic autoimmune response induces the recently described “chronic infection phenotype” in CD8+ T cells, which retains anti‐infectious effector features while exhibiting autoreactive cytolytic potential. This response is likely dampened by LIR‐1 to avoid overwhelming immunopathologic changes in the setting of the autoimmune disease RA. The known deficiency of soluble HLA–G in RA and the observed association of LIR‐1 expression with disease activity suggest, however, that LIR‐1+ T cells are insufficiently controlled in RA and are still likely to be involved in the pathogenesis of the disease.

Impaired NK-mediated regulation of T-cell activity in multiple sclerosis is reconstituted by IL-2 receptor modulation

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) resulting from a breakdown in peripheral immune tolerance. Although a beneficial role of natural killer (NK)-cell immune-regulatory function has been proposed, it still needs to be elucidated whether NK cells are functionally impaired as part of the disease. We observed NK cells in active MS lesions in close proximity to T cells. In accordance with a higher migratory capacity across the blood-brain barrier, CD56(bright) NK cells represent the major intrathecal NK-cell subset in both MS patients and healthy individuals. Investigating the peripheral blood and cerebrospinal fluid of MS patients treated with natalizumab revealed that transmigration of this subset depends on the α4β1 integrin very late antigen (VLA)-4. Although no MS-related changes in the migratory capacity of NK cells were observed, NK cells derived from patients with MS exhibit a reduced cytolytic activity in response to antigen-activated CD4(+) T cells. Defective NK-mediated immune regulation in MS is mainly attributable to a CD4(+) T-cell evasion caused by an impaired DNAX accessory molecule (DNAM)-1/CD155 interaction. Both the expression of the activating NK-cell receptor DNAM-1, a genetic alteration consistently found in MS-association studies, and up-regulation of the receptor's ligand CD155 on CD4(+) T cells are reduced in MS. Therapeutic immune modulation of IL-2 receptor restores impaired immune regulation in MS by increasing the proportion of CD155-expressing CD4(+) T cells and the cytolytic activity of NK cells.

The low EOMES/TBX21 molecular phenotype in multiple sclerosis reflects CD56+ cell dysregulation and is affected by immunomodulatory therapies

Multiple Sclerosis (MS) is an autoimmune disease treated by therapies targeting peripheral blood cells. We previously identified that expression of two MS-risk genes, the transcription factors EOMES and TBX21 (ET), was low in blood from MS and stable over time. Here we replicated the low ET expression in a new MS cohort (p<0.0007 for EOMES, p<0.028 for TBX21) and demonstrate longitudinal stability (p<10(-4)) and high heritability (h(2)=0.48 for EOMES) for this molecular phenotype. Genes whose expression correlated with ET, especially those controlling cell migration, further defined the phenotype. CD56+ cells and other subsets expressed lower levels of Eomes or T-bet protein and/or were under-represented in MS. EOMES and TBX21 risk SNP genotypes, and serum EBNA-1 titres were not correlated with ET expression, but HLA-DRB1*1501 genotype was. ET expression was normalised to healthy control levels with natalizumab, and was highly variable for glatiramer acetate, fingolimod, interferon-beta, dimethyl fumarate.

Safety and immunologic effects of high- vs low-dose cholecalciferol in multiple sclerosis

OBJECTIVE

To study the safety profile and characterize the immunologic effects of high- vs low-dose cholecalciferol supplementation in patients with multiple sclerosis (MS).

METHODS

In this double-blind, single-center randomized pilot study, 40 patients with relapsing-remitting MS were randomized to receive 10,400 IU or 800 IU cholecalciferol daily for 6 months. Assessments were performed at baseline and 3 and 6 months.

RESULTS

Mean increase of 25-hydroxyvitamin D levels from baseline to final visit was larger in the high-dose group (34.9 ng/mL; 95% confidence interval [CI] 25.0-44.7 ng/mL) than in the low-dose group (6.9 ng/mL; 95% CI 1.0-13.7 ng/mL). Adverse events were minor and did not differ between the 2 groups. Two relapses occurred, one in each treatment arm. In the high-dose group, we found a reduction in the proportion of interleukin-17(+)CD4(+) T cells (p = 0.016), CD161(+)CD4(+) T cells (p = 0.03), and effector memory CD4(+) T cells (p = 0.021) with a concomitant increase in the proportion of central memory CD4(+) T cells (p = 0.018) and naive CD4(+) T cells (p = 0.04). These effects were not observed in the low-dose group.

CONCLUSIONS

Cholecalciferol supplementation with 10,400 IU daily is safe and tolerable in patients with MS and exhibits in vivo pleiotropic immunomodulatory effects in MS, which include reduction of interleukin-17 production by CD4(+) T cells and decreased proportion of effector memory CD4(+) T cells with concomitant increase in central memory CD4(+) T cells and naive CD4(+) T cells.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that cholecalciferol supplementation with 10,400 IU daily is safe and well-tolerated in patients with MS and exhibits in vivo pleiotropic immunomodulatory effects.

Adaptive natural killer cell response to cytomegalovirus and disability progression in multiple sclerosis

BACKGROUND

Human cytomegalovirus (HCMV) causes a highly prevalent infection which may have a multifaceted impact on chronic inflammatory disorders. However, its potential influence in multiple sclerosis (MS) remains controversial. The HCMV-host interaction may induce an adaptive reconfiguration of the natural killer (NK) cell compartment, whose hallmark is a persistent expansion of peripheral NKG2C+ NK-cells.

OBJECTIVE

The purpose of this study was to evaluate whether the HCMV-driven NKG2C+ NK-cell expansion is related to the MS clinical course.

METHODS

Multicentre analysis of NKG2C expression and genotype according to HCMV serostatus and time of assignment of irreversible disability scores in 246 MS patients prospectively followed up in our institutions.

RESULTS

NKG2C expression was unrelated to disease-modifying drugs, remained stable under steady-state conditions, and was higher in HCMV(+) NKG2C(+/+) homozygous individuals. NKG2C+ NK-cell expansion in HCMV(+) patients, as compared to HCMV(+) or HCMV(-) patients with lower NKG2C+ NK-cells proportions, conferred a lower risk of progression in Cox regression analysis (Expanded Disability Status Scale (EDSS)>3.0, hazard ratio (HR)=0.33, 95% confidence interval (CI) 0.15-0.71, p=0.005; EDSS>5.5, HR=0.23, 95% CI 0.07-0.74, p=0.014). Neither HCMV serostatus nor NKG2C genotype appeared to be related to disability progression.

CONCLUSIONS

HCMV may exert a beneficial influence on MS, decreasing the risk of disability progression in those patients displaying a virus-driven NKG2C+ NK-cell expansion.

The Role of HLA in MS Susceptibility and Phenotype

One of the most consistent findings in multiple sclerosis (MS) is that development of MS is linked with carriage of the class II human leucocyte antigen (HLA) molecule HLA-DRB1*15:01; around 60 % of Caucasian MS patients carry this allele compared to 25-30 % of ethnically matched healthy individuals. However, other HLA molecules have also been linked to the development of MS. In this chapter, the association between different HLA types and susceptibility to MS will be reviewed, and other linkages between the carriage of specific HLA molecules and clinical and experimental findings in MS will be considered.

Killer-cell immunoglobulin-like receptor expression on lymphocyte subsets in multiple sclerosis patients treated with interferon-β: evaluation as biomarkers for clinical response

BACKGROUND

Both the adaptative and the innate immune systems interplay in multiple sclerosis (MS) pathogeny. Killer-cell immunoglobulin-like receptors (KIRs) are key regulators of the immune response, with activating and inhibitory isoforms.

OBJECTIVE

In this study we analysed whether the expression of KIR isoforms is implicated in MS pathogenesis and in the therapeutic response to interferon (IFN)-β.

METHODS

Peripheral blood samples were collected from 78 IFN-β-treated MS patients and 46 healthy controls (HC). KIR expression was evaluated by flow cytometry on natural killer (NK) and T cells.

RESULTS

The expression of KIRs on NK cells and T lymphocytes did not differ between MS patients and HC. IFN-β therapy decreased the expression of KIR2DL1/2DS1 and increased that of KIR2DL2/3 on NK cells. This therapy also reduced KIR2DL1/2DS1, KIR2DL2/2DL3 and KIR3DL2 expression on CD8(+) T cells. The baseline evaluation of the percentage of circulating CD16(+) NK cells was predictive of the clinical response to IFN-β; however, response to this therapy did not appear related to KIR expression.

CONCLUSIONS

This study shows that expression of KIR isoforms on NK and T lymphocytes correlated in different ways with IFN-β therapy, suggesting that KIR dynamics may be associated with the pathways involved in the mechanisms of action of IFN-β.

The role of natural killer cells in multiple sclerosis and their therapeutic implications

Multiple sclerosis (MS) is assumed to be an autoimmune disease initiated by autoreactive T cells that recognize central nervous system antigens. Although adaptive immunity is clearly involved in MS pathogenesis, innate immunity increasingly appears to be implicated in the disease. We and others have presented evidence that natural killer (NK) cells may be involved in immunoregulation in MS, leading to the question of whether a particular NK cell subtype will account for this effect. Changes of NK cell functionality in MS were associated with MS activity, and depletion of NK cells exacerbated the course of disease in a murine model of MS, experimental autoimmune encephalomyelitis. Several studies described a deficiency and transient "valleys" in NK cell killing activity in human MS, which may coincide with symptomatic relapse. However, the molecular basis of the defect in killing activity has not been determined. We discuss results on the expression of perforin in CD16(+) NK cells and the existence of an inverse relationship between myelin loaded phagocytes and the proportion of CD16(+) NK cells expressing perforin in the circulation. This inverse relationship is consistent with a role for NK cell killing activity in dampening autoimmunity. On the other hand, it has been broadly reported that first line MS therapies, such as interferon-beta, glatiramer acetate as well as escalation therapies such as fingolimod, daclizumab, or mitoxantrone seem to affect NK cell functionality and phenotype in vivo. Therefore, in this review we consider evidence for the immunoregulatory role of NK cells in MS and its animal models. Furthermore, we discuss the effect of MS treatments on NK cell activity.

Natural killer cells and their receptors in multiple sclerosis

The immune system has crucial roles in the pathogenesis of multiple sclerosis. While the adaptive immune cell subsets, T and B cells, have been the main focus of immunological research in multiple sclerosis, it is now important to realize that the innate immune system also has a key involvement in regulating autoimmune responses in the central nervous system. Natural killer cells are innate lymphocytes that play vital roles in a diverse range of infections. There is evidence that they influence a number of autoimmune conditions. Recent studies in multiple sclerosis and its murine model, experimental autoimmune encephalomyelitis, are starting to provide some understanding of the role of natural killer cells in regulating inflammation in the central nervous system. Natural killer cells express a diverse range of polymorphic cell surface receptors, which interact with polymorphic ligands; this interaction controls the function and the activation status of the natural killer cell. In this review, we discuss evidence for the role of natural killer cells in multiple sclerosis and experimental autoimmune encephalomyelitis. We consider how a change in the balance of signals received by the natural killer cell influences its involvement in the ensuing immune response, in relation to multiple sclerosis.

Killer immunoglobulin-like receptor locus polymorphisms in multiple sclerosis

OBJECTIVE

The objective of this study was to analyze whether inhibitory and activating killer cell immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I alleles defined by their KIR binding motifs are associated with multiple sclerosis (MS) susceptibility or severity.

METHOD

We performed a population-based case-control study in 321 patients with clinically isolated syndrome (CIS) and clinically definite MS (CDMS) and 156 healthy blood donors (HD). Inhibitory and activating KIRs and HLA class I alleles were genotyped using polymerase chain reaction (PCR) sequence-specific primers. Allelic frequencies were correlated with prevalence, age of onset, disability and disease duration of CIS and CDMS.

RESULTS

The frequency of the inhibitory KIR2DL3 gene was significantly reduced in patients with CIS and CDMS (p = 3.1 × 10(-5)). KIR2DL3-dependent risk reduction remained significant after elimination of patients carrying MS-associated DRB1*15, DRB1*03, DRB1*01 alleles. In addition, individuals carrying two copies for KIR2DL2/KIR2DS2 but lacking KIR2DL3 were overrepresented in the CIS/CDMS cohort. However, both genes did not affect disease risk in presence of KIR2DL3. We did not detect any association between the presence or absence of KIR genes with clinical disease parameters.

CONCLUSION

Absence of the inhibitory KIR2DL3 gene is associated with the development of CIS/CDMS. These findings, if confirmed in larger cohorts, suggest that KIR-mediated recognition of HLA class I molecules should be further explored as potential disease mechanism in MS.

Natural killer cell phenotype and clinical response to interferon-beta therapy in multiple sclerosis

CD56(bright) NK cells, which may play a role in immunoregulation, are expanded in multiple sclerosis (MS) patients treated with immunomodulatory therapies such as daclizumab and interferon-beta (IFNβ). Yet, whether this NK cell subset is directly involved in the therapeutic effect is unknown. As NK receptor (NKR) expression by subsets of NK cells and CD8+ T lymphocytes is related to MS clinical course, we addressed whether CD56(bright) NK cells and NKR in IFNβ-treated MS patients differ according to the clinical response. IFNβ was associated to lower LILRB1+ and KIR+NK cells, and higher NKG2A+NK cell proportions, an immunophenotypic pattern mainly found in responders. After IFNβ treatment, a CD56(bright) NK cell expansion was significantly related to a positive clinical response. Our results reveal that IFNβ may promote in responders changes in the NK cell immunophenotype, corresponding to the profile found at early maturation stages of this lymphocyte lineage.