Interleukin-7 expression and its effect on natural killer cells in patients with multiple sclerosis

Mapping the complexity of multiple sclerosis: a novel perspective on genetic, environmental, and neurobiological insights

Multiple sclerosis (MS) is the most common chronic demyelinating disease of the central nervous system (CNS) that mainly affects young adults. MS is a neuroinflammatory disease traditionally classified as an autoimmune disorder; however, its exact cause remains unknown. A wide variety of etiology and risk factors have been proposed to contribute, among which genetics and environment are the leading ones. The heterogeneity of MS can be attributed to a variety of factors, including diverse pathobiological mechanisms. In this narrative review, before discussing the most prevalent etiologies of MS and risk factors, we look at the main neurobiological pathways, blood-brain barrier (BBB) breakdown, and glymphatic system dysfunction. Several intrinsic factors, including genetics and epigenetic implications, hormones, immune system dysregulation, age, and microbiome, have definite roles in developing and worsening MS severity. However, external factors like viruses, bacteria, bioclimate impacts, environmental toxins, lifestyle factors, stress, and psychological factors revealed different or controversial impacts on MS disease. On the other hand, some nascent ones, such as intestinal dysbiosis and COVID-19, need to be further experimentally and clinically investigated. Both may contribute to MS by promoting inflammation and triggering autoimmune responses. Although it assumes that more than one factor contributes to MS development, finding the leading underlying cause and, consequently, the probable involvement mechanisms certainly could help take appropriate, efficient, and personalized therapeutic strategies.

High-throughput drug screening identifies SMAC mimetics as enhancers of NK-cell cytotoxicity in chronic myeloid leukemia

ABSTRACT

Natural killer (NK) cells have proven to be safe and effective immunotherapies, associated with favorable treatment responses in chronic myeloid leukemia (CML). Augmenting NK-cell function with oncological drugs could improve NK-cell-based immunotherapies. Here, we used a high-throughput drug screen consisting of >500 small-molecule compounds, to systematically evaluate the effects of oncological drugs on primary NK cells against CML cells. We identified second mitochondrially derived activator of caspases (SMAC) mimetics as potent enhancers of NK-cell cytotoxicity in both cell lines and primary patient samples. In contrast, several drug classes, including glucocorticoids and tyrosine kinase inhibitors such as dasatinib, inhibited NK-cell cytotoxicity. Single-cell RNA sequencing revealed drug-induced transcriptomic changes in both NK and target CML cells. SMAC mimetics upregulated NF-κB target genes in NK cells, potentially contributing to their enhanced cytotoxicity. Inhibitory drugs dexamethasone, dasatinib, and sotrastaurin prevented NK-cell transition to an activated state and suppressed the expression of interferon gamma (IFN-γ) by NK cells, thus preventing IFN-γ-mediated target cell transcriptomic response. In conclusion, we discovered that SMAC mimetics sensitize cancer cells to NK-cell-mediated killing, with potential clinical applications especially in patients with advanced phase CML.

A "Prime and Expand" strategy using the multifunctional fusion proteins to generate memory-like NK cells for cell therapy

Adoptive cellular therapy (ACT) using memory-like (ML) natural killer (NK) cells, generated through overnight ex vivo activation with IL-12, IL-15, and IL-18, has shown promise for treating hematologic malignancies. We recently reported that a multifunctional fusion molecule, HCW9201, comprising IL-12, IL-15, and IL-18 domains could replace individual cytokines for priming human ML NK cell programming ("Prime" step). However, this approach does not include ex vivo expansion, thereby limiting the ability to test different doses and schedules. Here, we report the design and generation of a multifunctional fusion molecule, HCW9206, consisting of human IL-7, IL-15, and IL-21 cytokines. We observed > 300-fold expansion for HCW9201-primed human NK cells cultured for 14 days with HCW9206 and HCW9101, an IgG1 antibody, recognizing the scaffold domain of HCW9206 ("Expand" step). This expansion was dependent on both HCW9206 cytokines and interactions of the IgG1 mAb with CD16 receptors on NK cells. The resulting "Prime and Expand" ML NK cells exhibited elevated metabolic capacity, stable epigenetic IFNG promoter demethylation, enhanced antitumor activity in vitro and in vivo, and superior persistence in NSG mice. Thus, the "Prime and Expand" strategy represents a simple feeder cell-free approach to streamline manufacturing of clinical-grade ML NK cells to support multidose and off-the-shelf ACT.

Advances in IL-7 Research on Tumour Therapy

Interleukin-7 (IL-7) is a versatile cytokine that plays a crucial role in regulating the immune system's homeostasis. It is involved in the development, proliferation, and differentiation of B and T cells, as well as being essential for the differentiation and survival of naïve T cells and the production and maintenance of memory T cells. Given its potent biological functions, IL-7 is considered to have the potential to be widely used in the field of anti-tumour immunotherapy. Notably, IL-7 can improve the tumour microenvironment by promoting the development of Th17 cells, which can in turn promote the recruitment of effector T cells and NK cells. In addition, IL-7 can also down-regulate the expression of tumour growth factor-β and inhibit immunosuppression to promote anti-tumour efficacy, suggesting potential clinical applications for anti-tumour immunotherapy. This review aims to discuss the origin of IL-7 and its receptor IL-7R, its anti-tumour mechanism, and the recent advances in the application of IL-7 in tumour therapy.

Interleukin-7 Biology and Its Effects on Immune Cells: Mediator of Generation, Differentiation, Survival, and Homeostasis

Interleukin-7 (IL-7), a molecule known for its growth-promoting effects on progenitors of B cells, remains one of the most extensively studied cytokines. It plays a vital role in health maintenance and disease prevention, and the congenital deficiency of IL-7 signaling leads to profound immunodeficiency. IL-7 contributes to host defense by regulating the development and homeostasis of immune cells, including T lymphocytes, B lymphocytes, and natural killer (NK) cells. Clinical trials of recombinant IL-7 have demonstrated safety and potent immune reconstitution effects. In this article, we discuss IL-7 and its functions in immune cell development, drawing on a substantial body of knowledge regarding the biology of IL-7. We aim to answer some remaining questions about IL-7, providing insights essential for designing new strategies of immune intervention.

Alginate/gelatin encapsulation promotes NK cells differentiation potential of bone marrow resident C-kit+ hematopoietic stem cells

The ability of natural killer (NK) cells to destroy cancerous cells with no prior sensitization has made them attractive candidates for cell therapy. The application of hydrogels must be notified as cell delivery vehicles in cell differentiation. The present study was conducted to investigate the effect of alginate-gelatin encapsulation on NK cell differentiation potential of C-kit+ cells. C-kit+ cells were differentiated to NK cells under both encapsulated and un-encapsulated conditions. Next, the cells were subjected to real-time polymerase chain reaction (PCR) and western blotting for the assessment of their telomere length and protein expressions, respectively. Afterward, culture medium was collected to measure cytokines levels. Thereafter, the differentiated NK cells were co-cultured with Molt-4 cells to investigate the potency of cell apoptosis by Annexin V/PI assay. A significant change was observed in the protein expression of Janus kinase/Signal transducers (JAK/STAT) pathway components. Additionally, the encapsulation caused an increase in the apoptosis of Molt-4 cells and telomere length of NK cells differentiated C-kit+ cells. Therefore, it can be concluded that the effects of encapsulation on NK cell's differentiation of C-kit+ cells could be resulted from the secreted cytokines of interleukin (IL)-2, IL-3, IL-7, and IL-12 as well as the increased telomere length.

Activated monocytes and markers of inflammation in newly diagnosed multiple sclerosis

In multiple sclerosis (MS), the inflammation and demyelination of the central nervous system (CNS) develop in distinct ways. This makes diagnosing patients difficult, imperative to initiating early and proper treatment. Several common features exist, among them a profound infiltration of monocytes into the CNS mediating demyelination and tissue destruction. In the periphery, monocytes are divided into three subsets depending on expression of CD14 and CD16, representing different stages of activation and differentiation. To investigate their involvement in MS, peripheral blood mononuclear cells (PBMCs) from 61 patients with incipient, untreated MS and 22 symptomatic control (SC) patients as well as 6 patients with radiologically isolated syndrome (RIS) were characterized ex vivo. In addition, paired serum and cerebrospinal fluid (CSF) samples were analyzed with a panel of biomarkers. In PBMC samples, we demonstrate decreased levels of nonclassical monocytes with a concomitant significant decrease of human endogenous retrovirus (HERV) H3 envelope epitopes on this monocyte subset compared with SC and RIS. The observed HERV expression is present on nonclassical monocytes irrespective of MS and thus presumably a result of the inflammatory activation. For the other surface markers analyzed, we found significantly decreased expression between classical and nonclassical monocytes. In matched samples of CSF a highly significant increase in levels of soluble markers of activation and inflammation is shown, and notably this is not the case for the serum samples. Of the soluble markers investigated, interleukin (IL)‐12/IL‐23p40 had the highest discriminatory power in differentiating patients with MS from SC and RIS, almost comparable to the immunoglobulin G index.

Natural killer cells in multiple sclerosis: A review

As the most common non-traumatic disabling disease among adolescents, multiple sclerosis (MS) is a devastating neurological inflammatory disease of the central nervous system. Research has not yet fully elucidated its pathogenesis, but it has shown MS to be a complex, multifactorial disease with many interplaying factors. One of these factors, natural killer (NK) cells, lymphocytes of the innate immune system, have recently gained attention due to the effects of daclizumab therapy, causing an expansion of the immunoregulatory subset of NK cells. Since then, NK cells and their relation to MS have been the focus of research, with many new findings being published in the last decade. In this review, NK cells are pictured as potent cytotoxic killers, as well as unique immune-regulators. Additionally, an overview of our current knowledge regarding NK cells in MS is given. The role of NK cells in MS is reviewed in the context of well-established environmental factors and current disease modifying therapies to gain further understanding of the pathogenesis and treatment options in MS.

Natural Killer Cells Regulate Th17 Cells After Autologous Hematopoietic Stem Cell Transplantation for Relapsing Remitting Multiple Sclerosis

In autoimmunity, the balance of different helper T (Th) cell subsets can influence the tissue damage caused by autoreactive T cells. Pro-inflammatory Th1 and Th17 T cells are implicated as mediators of several human autoimmune conditions such as multiple sclerosis (MS). Autologous hematopoietic stem cell transplantation (aHSCT) has been tested in phase 2 clinical trials for MS patients with aggressive disease. Abrogation of new clinical relapses and brain lesions can be seen after ablative aHSCT, accompanied by significant reductions in Th17, but not Th1, cell populations and activity. The cause of this selective decrease in Th17 cell responses following ablative aHSCT is not completely understood. We identified an increase in the kinetics of natural killer (NK) cell reconstitution, relative to CD4⁺ T cells, in MS patients post-aHSCT, resulting in an increased NK cell:CD4⁺ T cell ratio that correlated with the degree of decrease in Th17 responses. Ex vivo removal of NK cells from post-aHSCT peripheral blood mononuclear cells resulted in higher Th17 cell responses, indicating that NK cells can regulate Th17 activity. NK cells were also found to be cytotoxic to memory Th17 cells, and this toxicity is mediated through NKG2D-dependent necrosis. Surprisingly, NK cells induced memory T cells to secrete more IL-17A. This was preceded by an early rise in T cell expression of RORC and IL17A mRNA, and could be blocked with neutralizing antibodies against CD58, a costimulatory receptor expressed on NK cells. Thus, NK cells provide initial co-stimulation that supports the induction of a Th17 response, followed by NKG2D-dependent cytotoxicity that limits these cells. Together these data suggest that rapid reconstitution of NK cells following aHSCT contribute to the suppression of the re-emergence of Th17 cells. This highlights the importance of NK cells in shaping the reconstituting immune system following aHSCT in MS patients.

Cloning and Expression of Recombinant Human Interleukin-7 in Chinese Hamster Ovary (CHO) Cells

BACKGROUND

The critical role of interleukin-7 (IL-7) in homeostatic proliferation and T cell survival has made it a promising cytokine for the treatment of various clinical conditions, especially those associated with lymphopenia.

METHODS

In the present study we expressed recombinant human interleukin-7 (rhIL-7) in Chinese hamster ovary (CHO)-K1 cells. CHO-K1 cells were stably transfected with both circular and linear forms of the pBud-hIL-7 recombinant by electroporation. Expression of rhIL-7 in CHO-K1 cells was confirmed by enzyme-linked immunosorbent assay (ELISA) and dot and western blots.

RESULTS

On western blots of transformed cells, a single 25 kDa band was observed, consistent with the expected molecular weight of glycosylated hIL-7. No significant expression difference was observed between cells transfected with circular or linear plasmids.

CONCLUSION

We established a stable CHO-K1 cell line expressing rhIL-7, which we consider to be a promising system for the production of rhIL-7 as a biopharmaceutical.

CD56bright NK IL-7Rα expression negatively associates with HCV level, and IL-7-induced NK function is impaired during HCV and HIV infections

Several lines of evidence support the concept that NK cells play an important role in control of hepatitis C virus (HCV) infection via cytokine secretion and cytotoxicity. IL-7 is a homeostatic cytokine with a role in T cell development, activation, proliferation, and cytokine secretion. The IL-7Rα chain [cluster of differentiation (CD)127] is expressed on NK cells, with greatest abundance on the CD56^brightCD16^dim/- (CD56^bright) subset. Here, we measured CD127 expression on CD56^bright, CD56^dimCD16⁺ (CD56^dim), or CD56^negCD16⁺ (CD56^neg) NK cell subsets of 25 uninfected donors (UD); 34 chronic HCV-infected, treatment-naïve; 25 HIV-infected, virally suppressed on antiretroviral therapy (ART); and 42 HCV-HIV-coinfected subjects on ART. Interestingly, CD127 expression on CD56^bright NK cells negatively correlated with HCV plasma levels in HCV monoinfection and HCV-HIV coinfection. IL-7 induced CD69 expression, as well as IFN-γ production, in CD56^bright NK cells and also enhanced the IFN-α-induced CD69 expression on these cells. The latter was impaired in HIV infection. Furthermore, IL-7 induced B cell lymphoma 2 (BCL-2) expression and cell cycling of CD56^bright NK cells, and this effect was impaired in HCV- and HIV-infected subjects. Whereas IL-7-stimulated CD56^bright NK cell degranulation appeared intact in all cohorts, we observed impaired IL-7-activated NK cell cytolytic function in HCV- and HIV-infected subjects. Finally, IL-7-induced phosphorylation of STAT-5 (pSTAT-5) signaling was impaired in NK cells of subjects with chronic viral infection, and this was reversible upon 6 mo of viral suppression with IFN-free HCV therapy. These results implicate that IL-7-dependent NK cell activation and effector function may be other host immune surveillance mechanisms that are impaired in viral infections.

CD27 natural killer cell subsets play different roles during the pre-onset stage of experimental autoimmune encephalomyelitis

NK cells participate in the development of human multiple sclerosis (MS) and mouse experimental autoimmune encephalomyelitis (EAE), but the roles of different NK cell subsets in disease onset remain poorly understood. In this study, murine NK cells were divided into CD27high and CD27low/− subsets. The CD27high subset was decreased and the CD27low/− subset was increased in lymphoid organs during the pre-onset stage of EAE. Compared with the counterpart in naïve mice, the CD27high subset showed lower expression of Ly49D, Ly49H and NKG2D, and less production of IFN-γ, whereas the CD27low/− subset showed similar expression of the above mentioned surface receptors but higher cytotoxic activity in EAE mice. Compared with the CD27high subset, the CD27low/− subset exhibited increased promotion of DC maturation and no significant inhibition of T cells proliferation and Th17 cells differentiation in vitro. Additionally, adoptive transfer of the CD27low/− subset, but not the CD27high subset, exacerbated the severity of EAE. Collectively, our data suggest the CD27 NK cell subsets play different roles in controlling EAE onset, which provide a new understanding for the regulation of NK cell subsets in early autoimmune disease.