Molecular pathways: interleukin-15 signaling in health and in cancer

Effects of dietary melatonin supplementation on growth performance and intestinal health of rice field eel (Monopterus albus)

The objective was to assess the impact of melatonin supplementation on the growth performance and intestinal health of rice field eel, Monopterus albus. Three hundred and sixty fish (28.46 ± 0.24 g) were fed five diets supplemented with melatonin of 0, 30, 60, 120, and 240 mg/kg for 70 days. The study found that the variables FBW, WGR, SGR, and FCR exhibited a statistically significant quadratic relationship (P < 0.05) with the dietary melatonin concentrations, and the highest FBW, WGR and SGR as well as lowest FCR were observed in the 120 mg/kg melatonin group, digestive enzymes activities (such as amylase, trypsin, and lipase) also had significant quadratic relationship (P < 0.05), and the highest intestinal villus height and goblet cells were found in the 120 mg/kg diet (P < 0.01), melatonin in diets significantly increased SOD and CAT activities in serum, up-regulated the expression of anti-inflammatory factors (IL-10) and tight junction protein (ZO-1), and down-regulated the expression of pro-inflammatory factors (IL-1β, IL-8, IL-15, and TNF-α) in the gut, dietary melatonin improved the intestinal microflora compositions, in the group that supplementation a dosage of 120 mg/kg, there was a noticeable rise in the abundance of Firmicutes and the ratio of Firmicutes/Bacteroidota, compared with control group (P < 0.1). Conclusively, dietary supplementation of melatonin promoted growth performance, enhanced intestinal immune capacity and serum antioxidant level, and improved intestinal morphology properties and intestinal flora composition in M. albus. In conclusion, based on quadratic broken-line regression analysis of WGR and FCR, the optimal concentration of melatonin to be supplied is predicted to be 146-148 mg/kg.

Advances in research on factors affecting chimeric antigen receptor T-cell efficacy

Chimeric antigen receptor T-cell (CAR-T) therapy is becoming an effective technique for the treatment of patients with relapsed/refractory hematologic malignancies. After analyzing patients with tumor progression and sustained remission after CAR-T cell therapy, many factors were found to be associated with the efficacy of CAR-T therapy. This paper reviews the factors affecting the effect of CAR-T such as tumor characteristics, tumor microenvironment and immune function of patients, CAR-T cell structure, construction method and in vivo expansion values, lymphodepletion chemotherapy, and previous treatment, and provides a preliminary outlook on the corresponding therapeutic strategies.

Emerging roles of type 1 innate lymphoid cells in tumour pathogenesis and cancer immunotherapy

Innate lymphoid cells (ILCs) are the most recently discovered class of innate immune cells found to have prominent roles in various human immune-related pathologies such as infection and autoimmune diseases. However, their role in cancer was largely unclear until recently, where several emerging studies over the past few years unanimously demonstrate ILCs to be critical players in tumour immunity. Being the innate counterpart of T cells, ILCs are potent cytokine producers through which they orchestrate the overall immune response upstream of adaptive immunity thereby modulating T cell function. Out of the major ILC subsets, ILC1s have gained significant traction as potential immunotherapeutic candidates due to their central involvement with the anti-tumour type 1 immune response. ILC1s are potent producers of the well-established anti-tumour cytokine interferon γ (IFNγ), and exert direct cytotoxicity against cancer cells in response to the cytokine interleukin-15 (IL-15). However, in advanced diseases, ILC1s are found to demonstrate an exhausted phenotype in the tumour microenvironment (TME) with impaired effector functions, characterised by decreased responsiveness to cytokines and reduced IFNγ production. Tumour cells produce immunomodulatory cytokines such as transforming growth factor β (TGFβ) and IL-23, and through these suppress ILC1 anti-tumour actfivities and converts ILC1s to pro-tumoural ILC3s respectively, resulting in disease progression. This review provides a comprehensive overview of ILC1s in tumour immunity, and discusses the exciting prospects of harnessing ILC1s for cancer immunotherapy, either alone or in combination with cytokine-based treatment. The exciting prospects of targeting the upstream innate immune system through ILC1s may surmount the limitations associated with adaptive immune T cell-based strategies used in the clinic currently, and overcome cancer immunotherapeutic resistance.

Lung cancer cell-intrinsic IL-15 promotes cell migration and sensitizes murine lung tumors to anti-PD-L1 therapy

BACKGROUND

IL-15 plays a vital role in enhancing NK cell- and T-cell-mediated antitumor immune responses; however, the direct effect of IL-15 on tumor cells has not been fully elucidated. Herein, we investigated the effect of IL-15 on lung adenocarcinoma cells.

METHODS

Silencing and overexpression techniques were used to modify endogenous IL-15 expression in tumor cells. Transwell assays were used to assess tumor cell migration and invasion; a live-cell analysis system was used to evaluate cell motility; cellular morphological changes were quantified by confocal fluorescence microscopy; the molecular mechanisms underlying the effect of IL-15 on tumor cells were analyzed by western blotting; and RhoA and Cdc42 activities were evaluated by a pulldown assay. NCG and C57BL/6 mouse models were used to evaluate the functions of IL-15 in vivo.

RESULTS

Cancer cell-intrinsic IL-15 promoted cell motility and migration in vitro and metastasis in vivo via activation of the AKT-mTORC1 pathway; however, exogenous IL-15 inhibited cell motility and migration via suppression of the RhoA-MLC2 axis. Mechanistic analysis revealed that both the intracellular and extracellular IL-15-mediated effects required the expression of IL-15Rα by tumor cells. Detailed analyses revealed that the IL-2/IL-15Rβ and IL-2Rγ chains were undetected in the complex formed by intracellular IL-15 and IL-15Rα. However, when exogenous IL-15 engaged tumor cells, a complex containing the IL-15Rα, IL-2/IL-15Rβ, and IL-2Rγ chains was formed, indicating that the differential actions of intracellular and extracellular IL-15 on tumor cells might be caused by their distinctive modes of IL-15 receptor engagement. Using a Lewis lung carcinoma (LLC) metastasis model, we showed that although IL-15 overexpression facilitated the lung metastasis of LLC cells, IL-15-overexpressing LLC tumors were more sensitive to anti-PD-L1 therapy than were IL-15-wild-type LLC tumors via an enhanced antitumor immune response, as evidenced by their increased CD8+ T-cell infiltration compared to that of their counterparts.

CONCLUSIONS

Cancer cell-intrinsic IL-15 and exogenous IL-15 differentially regulate cell motility and migration. Thus, cancer cell-intrinsic IL-15 acts as a double-edged sword in tumor progression. Additionally, high levels of IL-15 expressed by tumor cells might improve the responsiveness of tumors to immunotherapies.

Enhancing cancer immunotherapy with Anti-NKG2D/IL-15(N72D)/Sushi fusion protein: Targeting cytotoxic immune cells and boosting IL-15 efficacy

BACKGROUND

There are a number of distinct challenges and complexities associated with administering IL-15 for cancer immunotherapy that must be taken into consideration.

OBJECTIVE

The purpose of this study was to design a fusion protein for targeting cytotoxic immune cells and enhance IL-15 efficiency.

METHODS

A fusokine that contains IL-15(N72D), a Sushi domain, and anti-NKG2D scFv was designed. The fusion protein was in-silico modeled using the Swiss model server, followed by docking and molecular dynamics simulations. The in-vitro purified fusokine was evaluated using dot blot and Western blot. Then, flow cytometry was employed to evaluate biological properties such as proliferation, cytotoxicity, and degranulation.

RESULTS

Fusokine and IL-15(N72D)/Sushi, which had molecular weights of about 52 kDa and 26 kDa, respectively, were expressed in CHO-K1 cells. The fusokine binds 69.6 % of the CHO-NKG2D+ cells that express 83.1 % NKG2D. Both the fusokine and the IL-15(N72D)/Sushi significantly stimulate the proliferation of lymphocytes. After 14 days of growth, the vitality of untreated cells decreased to about 17.5 %, but 82.2 % and 56.6 % of cells were still alive when fusokine and IL-15(N72D)/Sushi were present. Furthermore, administration of fusokine was associated with the highest rates of target tumor cell cytotoxicity. Additionally, although it was not statistically significant, fusokine increased the expression of CD107a and granzyme B by 1.25 times and 2.4 times, respectively.

CONCLUSION

The fusokine possesses the capability to stimulate the survival and multiplication of lymphocytes, as well as their ability to eliminate tumors. These characteristics have led to its consideration as a potential treatment for immunotherapy.

Large Granular Lymphocytic Leukemia: Clinical Features, Molecular Pathogenesis, Diagnosis and Treatment

Large granular lymphocytic (LGL) leukemia is a lymphoproliferative disorder characterized by persistent clonal expansion of mature T- or natural killer cells in the blood via chronic antigenic stimulation. LGL leukemia is associated with specific immunophenotypic and molecular features, particularly STAT3 and STAT5 mutations and activation of the JAK-STAT3, Fas/Fas-L and NF-κB signaling pathways. Disease-related deaths are mainly due to recurrent infections linked to severe neutropenia. The current treatment is based on immunosuppressive therapies, which frequently produce unsatisfactory long-term responses, and for this reason, personalized approaches and targeted therapies are needed. Here, we discuss molecular pathogenesis, clinical presentation, associated autoimmune disorders, and the available treatment options, including emerging therapies.

Signalling mechanisms driving homeostatic and inflammatory effects of interleukin-15 on tissue lymphocytes

There is an intriguing dichotomy in the function of cytokine interleukin-15-at low levels, it is required for the homeostasis of the immune system, yet when it is upregulated in response to pathogenic infections or in autoimmunity, IL-15 drives inflammation. IL-15 associates with the IL-15Rα within both myeloid and non-haematopoietic cells, where IL-15Rα trans-presents IL-15 in a membrane-bound form to neighboring cells. Alongside homeostatic maintenance of select lymphocyte populations such as NK cells and tissue-resident T cells, when upregulated, IL-15 also promotes inflammatory outcomes by driving effector function and cytotoxicity in NK cells and T cells. As chronic over-expression of IL-15 can lead to autoimmunity, IL-15 expression is tightly regulated. Thus, blocking dysregulated IL-15 and its downstream signalling pathways are avenues for immunotherapy. In this review we discuss the molecular pathways involved in IL-15 signalling and how these pathways contribute to both homeostatic and inflammatory functions in IL-15-dependent mature lymphoid populations, focusing on innate, and innate-like lymphocytes in tissues.

GT-00AxIL15, a Novel Tumor-Targeted IL-15-Based Immunocytokine for the Treatment of TA-MUC1-Positive Solid Tumors: Preclinical In Vitro and In Vivo Pharmacodynamics and Biodistribution Studies

GT-00AxIL15 is a novel interleukin-15-based immunocytokine targeting a tumor-specific, glycosylated epitope of MUC1 (TA-MUC1). We characterized mode of action, pharmacokinetic (PK) and pharmacodynamic (PD) properties and investigated the relevance of TA-MUC1 binding for the concept of delivering IL-15 to solid tumors. In vitro pharmacology was analyzed in binding and cell-based assays. The in vivo PK profile and IL-15-mediated PD effects of GT-00AxIL15 were investigated in tumor-free mice. Tumor accumulation, immune infiltration and anti-tumor activity were assessed in TA-MUC1+ syngeneic and xenogeneic murine tumor models. GT-00AxIL15 was shown to specifically bind TA-MUC1 on tumor cells via its mAb moiety, to IL-15 receptors on immune cells via its IL-15 fusion modules and to FcγRs via its functional Fc-part. In vitro, NK, NKT and CD8+ T cells were activated and proliferated, leading to anti-tumor cytotoxicity and synergism with antibody-dependent cellular cytotoxicity (ADCC)-mediating mAbs. In vivo, GT-00AxIL15 exhibited favorable PK characteristics with a serum half-life of 13 days and specifically accumulated in TA-MUC1+ tumors. In the tumor microenvironment, GT-00AxIL15 induced robust immune activation and expansion and mediated anti-metastatic and anti-tumor effects in syngeneic and xenograft tumor models. These results support the rationale to improve PK and anti-tumor efficacy of IL-15 by increasing local concentrations at the tumor site via conjugation to a TA-MUC1 binding mAb. The tumor-selective expression pattern of TA-MUC1, powerful immune activation and anti-tumor cytotoxicity, long serum half-life and tumor targeting properties, render GT-00AxIL15 a promising candidate for treatment of solid tumors with high medical need, e.g., ovarian, lung and breast cancer.

Interleukin-15 responses to acute and chronic exercise in adults: a systematic review and meta-analysis

Purpose

Interlukin-15 (IL-15) is an inflammatory cytokine that plays a vital role in immunology and obesity-associated metabolic syndrome. We performed this systematic review and meta-analysis to investigate whether exercise promotes circulating IL-15 concentrations in adults.

Methods

We searched PubMed, Web of Science, and Scopus from inception to May, 2023 and identified original studies that investigated the effectiveness of acute and/or chronic exercise on serum/plasma IL-15 levels in adults. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using random effect models. Subgroup analyses were performed based on type of exercise, and training status, health status and body mass indexes (BMI) of participants.

Results

Fifteen studies involving 411 participants and 12 studies involving 899 participants were included in the acute and chronic exercise analyses, respectively. Our findings showed that acute exercise increased circulating IL-15 concentrations immediately after exercise compared with baseline [SMD=0.90 (95% CI: 0.47 to 1.32), p=0.001], regardless of exercise type and participants' training status. Similarly, acute exercise was also associated with increased IL-15 concentrations even one-hour after exercise [SMD=0.50 (95% CI: 0.00 to 0.99), p=0.04]. Nevertheless, chronic exercise did not have a significant effect on IL-15 concentrations [SMD=0.40 (95% CI: -0.08 to 0.88), p=0.10].

Conclusion

Our results confirm that acute exercise is effective in increasing the IL-15 concentrations immediately and one-hour after exercise intervention, and thereby playing a potential role in improving metabolism in adults.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=445634, identifier CRD42023445634.

Current Development Status of Cytokines for Cancer Immunotherapy

Cytokines influence the overall cancer immune cycle by triggering tumor antigen expression, antigen presenting, immune cell priming and activation, effector immune cell recruitment and infiltration to cancer, and cancer killing in the tumor microenvironment (TME). Therefore, cytokines have been considered potential anti-cancer immunotherapy, and cytokine-based anti-cancer therapies continue to be an active area of research and development in the field of cancer immunotherapy, with ongoing clinical trials exploring new strategies to improve efficacy and safety. In this review, we examine past and present clinical developments for major anticancer cytokines, including interleukins (IL-2, IL-15, IL-12, IL-21), interferons, TGF-beta, and GM-CSF. We identify the current status and changes in the technology platform being applied to cytokine-based immune anti-cancer therapeutics. Through this, we discuss the opportunities and challenges of cytokine-based immune anti-cancer treatments in the current immunotherapy market and suggest development directions to enhance the clinical use of cytokines as immuno-anticancer drugs in the future.

Protective effects of metformin in the pro-inflammatory cytokine induced intestinal organoids injury model

Pathogenesis of inflammatory bowel disease (IBD) accompanies disrupted intestinal tight junctions. However, many approaches of therapeutics for IBD are focused only on anti-inflammatory effects and most cellular experiments are based on two-dimensional cell lines which have insufficient circumstances of intestine. Thus, here, we used three-dimensional structure intestinal organoids to investigate effects of metformin in the in vitro IBD condition. In this study, we focused on both tight junctions and the levels of inflammatory cytokines. Metformin enhances the intestinal barrier in injured intestine via upregulation of AMP-activated protein kinase, dysfunction of which contributes to the pathogenesis of intestinal diseases. We aim to investigate the effects of metformin on cytokine-induced injured intestinal organoids. Tumor necrosis factor-alpha (TNF-α) was used to induce intestinal injury in an organoid model, and the effects of metformin were assessed. Cell viability and levels of inflammatory cytokines were quantified in addition to tight junction markers. Furthermore, 4 kDa FITC-dextran was used to assess intestinal permeability. The upregulation of inflammatory cytokine levels was alleviated by metformin, which also restored the intestinal epithelium permeability in TNF-α-treated injury organoids. We confirmed that claudin-2 and claudin-7, representative tight junction markers, were also protected by metformin treatment. This study confirms the protective effects of metformin, which could be used as a therapeutic strategy for inflammatory intestinal diseases.

Estimation of serum and tissue level of interleukin-15 (IL-15) and IL-15 receptor alpha (IL-15Rα) in mycosis fungoides before and after phototherapy: An interventional cohort study

BACKGROUND

Mycosis fungoides (MF) is a chronic, highly recurrent cutaneous T-cell lymphoma, whose pathogenesis has not yet been fully elucidated. Interleukin-15 was previously highlighted as a viability factor for cutaneous T-cell lymphoma with previous studies shedding light on its role in pathogenesis of MF and its plausibility as a potential therapeutic target.

OBJECTIVE

This study was conducted to evaluate serum and tissue expression of IL-15 and IL-15Rα in early cases of MF (IA, IB, IIA) at baseline and following phototherapy.

MATERIALS AND METHODS

Fourteen early MF cases were recruited. Samples were withdrawn prior to starting phototherapy treatment and following near complete clearance of the biopsied lesion or after a maximum of 36 sessions of phototherapy. Samples were assessed for change in expression of IL-15 and IL-15 Rα levels following treatment, whose levels were compared to healthy controls.

RESULTS

Serum and tissue levels of IL-15 and IL-15Rα in early MF cases were significantly higher at baseline than their levels following phototherapy treatment and higher than healthy controls. However, they dropped significantly following treatment with no statistical difference between treated cases and controls, apart from serum IL-15Rα that remained significantly elevated than controls.

CONCLUSION

Interleukin-15 and its receptor alpha appear to contribute to the pathogenesis of MF, being significantly elevated than healthy controls, which were normalized following phototherapy treatment, apart from serum IL-15Rα, which remained elevated. Controlling IL-15/IL-15Rα expression is a newly proposed mechanism of action of phototherapy in MF.

Abnormal M1 polarization of placental macrophage induced by IL-15/STAT5 activation in VVC may lead to adverse pregnancy outcomes

Pregnant women with vulvovaginal candidiasis (VVC) may experience adverse pregnancy outcomes such as premature delivery, intrauterine infection, abortion, and neonatal infection. Therefore, finding new treatments for VVC in pregnancy is a public health priority. We aimed to study the adverse consequences of Candida albicans (C. albicans) vaginal infection in pregnant mice and explore the mechanisms by which C. albicans affects macrophages. Our findings contribute to the development of new approaches to treat VVC during pregnancy. We established an animal model of vaginal infection by C. albicans in pregnant mice and observed adverse pregnancy outcomes such as decreased body weight, reduced implantation number, and increased abortion rates. Additionally, we infected mouse macrophage line RAW264.7 cells with C. albicans and established a cell model. We employed RT-qPCR, Western blot, and immunofluorescence staining to verify the changes in the IL-15/STAT5 signaling pathway and the role it played on the M1 polarization of C. albicans-infected macrophages at both the gene and protein levels. Our results indicate that the adverse pregnancy outcomes in VVC may be linked to changes in the IL-15/STAT5 pathway induced by C. albicans, which could impact macrophage M1 polarization.

New insights into the stemness of adoptively transferred T cells by γc family cytokines

T cell-based adoptive cell therapy (ACT) has exhibited excellent antitumoral efficacy exemplified by the clinical breakthrough of chimeric antigen receptor therapy (CAR-T) in hematologic malignancies. It relies on the pool of functional T cells to retain the developmental potential to serially kill targeted cells. However, failure in the continuous supply and persistence of functional T cells has been recognized as a critical barrier to sustainable responses. Conferring stemness on infused T cells, yielding stem cell-like memory T cells (TSCM) characterized by constant self-renewal and multilineage differentiation similar to pluripotent stem cells, is indeed necessary and promising for enhancing T cell function and sustaining antitumor immunity. Therefore, it is crucial to identify TSCM cell induction regulators and acquire more TSCM cells as resource cells during production and after infusion to improve antitumoral efficacy. Recently, four common cytokine receptor γ chain (γc) family cytokines, encompassing interleukin-2 (IL-2), IL-7, IL-15, and IL-21, have been widely used in the development of long-lived adoptively transferred TSCM in vitro. However, challenges, including their non-specific toxicities and off-target effects, have led to substantial efforts for the development of engineered versions to unleash their full potential in the induction and maintenance of T cell stemness in ACT. In this review, we summarize the roles of the four γc family cytokines in the orchestration of adoptively transferred T cell stemness, introduce their engineered versions that modulate TSCM cell formation and demonstrate the potential of their various combinations. Video Abstract.

RNA N6-methyladenosine methylation and skin diseases

Skin diseases are global health issues caused by multiple pathogenic factors, in which epigenetics plays an invaluable role. Post-transcriptional RNA modifications are important epigenetic mechanism that regulate gene expression at the genome-wide level. N6-methyladenosine (m6A) is the most prevalent modification that occurs in the messenger RNAs (mRNA) of most eukaryotes, which is installed by methyltransferases called "writers", removed by demethylases called "erasers", and recognised by RNA-binding proteins called "readers". To date, m6A is emerging to play essential part in both physiological processes and pathological progression, including skin diseases. However, a systematic summary of m6A in skin disease has not yet been reported. This review starts by illustrating each m6A-related modifier specifically and their roles in RNA processing, and then focus on the existing research advances of m6A in immune homeostasis and skin diseases.

Potentiation of natural killer cells to overcome cancer resistance to NK cell-based therapy and to enhance antibody-based immunotherapy

Natural killer (NK) cells are cellular components of the innate immune system that can recognize and suppress the proliferation of cancer cells. NK cells can eliminate cancer cells through direct lysis, by secreting perforin and granzymes, or through antibody-dependent cell-mediated cytotoxicity (ADCC). ADCC involves the binding of the Fc gamma receptor IIIa (CD16), present on NK cells, to the constant region of an antibody already bound to cancer cells. Cancer cells use several mechanisms to evade antitumor activity of NK cells, including the accumulation of inhibitory cytokines, recruitment and expansion of immune suppressor cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), modulation of ligands for NK cells receptors. Several strategies have been developed to enhance the antitumor activity of NK cells with the goal of overcoming cancer cells resistance to NK cells. The three main strategies to engineer and boost NK cells cytotoxicity include boosting NK cells with modulatory cytokines, adoptive NK cell therapy, and the employment of engineered NK cells to enhance antibody-based immunotherapy. Although the first two strategies improved the efficacy of NK cell-based therapy, there are still some limitations, including immune-related adverse events, induction of immune-suppressive cells and further cancer resistance to NK cell killing. One strategy to overcome these issues is the combination of monoclonal antibodies (mAbs) that mediate ADCC and engineered NK cells with potentiated anti-cancer activity. The advantage of using mAbs with ADCC activity is that they can activate NK cells, but also favor the accumulation of immune effector cells to the tumor microenvironment (TME). Several clinical trials reported that combining engineered NK cells with mAbs with ADCC activity can result in a superior clinical response compared to mAbs alone. Next generation of clinical trials, employing engineered NK cells with mAbs with higher affinity for CD16 expressed on NK cells, will provide more effective and higher-quality treatments to cancer patients.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

Effective treatment with the selective cytokine inhibitor BNZ-1 reveals the cytokine dependency of T-LGL leukemia

T-cell large granular lymphocytic leukemia (T-LGLL) is a clonal proliferation of cytotoxic T lymphocytes that can result in severe neutropenia, anemia, and bone marrow failure. Strong evidence from patients and mouse models demonstrate the critical role of interleukin-15 (IL-15) in T-LGLL pathogenesis. BNZ-1 is a pegylated peptide that selectively inhibits the binding of IL-15 and other γc cytokines to their cellular receptor complex, which has demonstrated efficacy in ex vivo T-LGLL cells and transgenic mice in preclinical studies. We conducted a phase 1/2 trial of BNZ-1 in patients with T-LGLL who had hematocytopenias (anemia or neutropenia) and required therapy. Clinical responses were assessed using hematologic parameters (improvement in hematocytopenias) based on response criteria from the Eastern Cooperative Oncology Group 5998 T-LGLL trial. BNZ-1 demonstrated clinical partial responses in 20% of patients with T-LGLL with minimal toxicity and the maximum tolerated dose was not reached. Furthermore, T-LGL leukemic cells showed significantly increased apoptosis in response to BNZ-1 treatment as early as day 2, including in clinical nonresponders, with changes that remained statistically different from baseline throughout treatment (P < .005). We report first-in-human proof that T-LGL leukemic cells are dependent on IL-15 and that intervention with IL-15 inhibition with BNZ-1 in patients with T-LGLL shows therapeutic effects, which carries important implications for the understanding of the pathogenesis of this disease. This trial was registered at www.clinicaltrials.gov as #NCT03239392.

Coordinated Priming of NKG2D Pathway by IL-15 Enhanced Functional Properties of Cytotoxic CD4+CD28- T Cells Expanded in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder, and numerous aberrations of T cell responses have been reported and were implicated in its pathophysiology. Recently, CD4-positive T cells with cytotoxic potential were shown to be involved in autoimmune disease progression and tissue damage. However, the effector functions of this cell type and their potential molecular mechanisms in SLE patients remain to be elucidated. In this study, we find that cytotoxic CD4+CD28- T cells are expanded in SLE patients with flow cytometry analysis, and the percentage of CD4+CD28- T cells positively correlates with the Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI). Furthermore, our study suggests that interleukin-15 (IL-15) promotes the expansion, proliferation, and cytotoxic function of CD4+CD28- T cells in SLE patients through activation of the Janus kinase3-STAT5 pathway. Further study indicates that IL-15 not only mediates the upregulation of NKG2D, but also cooperates with the NKG2D pathway to regulate the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway. Together, our study demonstrated that proinflammatory and cytolytic CD4+CD28- T cells expand in SLE patients. The pathogenic potential of these CD4+CD28- T cells is driven by the coupling of the IL-15/IL-15R signaling pathway and the NKG2D/DAP10 signaling pathway, which may open new avenues for therapeutic intervention to prevent SLE progression.

Microenvironment-dependent growth of Sezary cells in humanized IL-15 mice

Sezary syndrome (SS) is a rare, aggressive leukemic variant of cutaneous T-cell lymphoma (CTCL) that lacks adequate therapeutic options and representative small-animal models. Here, we demonstrate that IL-15 is a critical CTCL growth factor. Importantly, an immunodeficient knock-in mouse model genetically engineered to express human IL-15 uniquely supported the growth of SS patient samples relative to conventional immunodeficient mouse strains. SS patient-derived xenograft (PDX) models recapacitated key pathological features of the human disease, including skin infiltration and spread of leukemic cells to the periphery, and maintained the dependence on human IL-15 upon serial in vivo passaging. Detailed molecular characterization of the engrafted cells by single-cell transcriptomic analysis revealed congruent neoplastic gene expression signatures but distinct clonal engraftment patterns. Overall, we document an important dependence of Sezary cell survival and proliferation on IL-15 signaling and the utility of immunodeficient humanized IL-15 mice as hosts for SS - and potentially other T and NK cell-derived hematologic malignancies - PDX model generation. Furthermore, these studies advocate the thorough molecular understanding of the resultant PDX models to maximize their translational impact.

Integrated analysis of proteomics, epigenomics and metabolomics data revealed divergent pathway activation patterns in the recent versus chronic post-traumatic stress disorder

Metabolomics, proteomics and DNA methylome assays, when done in tandem from the same blood sample and analyzed together, offer an opportunity to evaluate the molecular basis of post-traumatic stress disorder (PTSD) course and pathogenesis. We performed separate metabolomics, proteomics, and DNA methylome assays on blood samples from two well-characterized cohorts of 159 active duty male participants with relatively recent onset PTSD (<1.5 years) and 300 male veterans with chronic PTSD (>7 years). Analyses of the multi-omics datasets from these two independent cohorts were used to identify convergent and distinct molecular profiles that might constitute potential signatures of severity and progression of PTSD and its comorbid conditions. Molecular signatures indicative of homeostatic processes such as signaling and metabolic pathways involved in cellular remodeling, neurogenesis, molecular safeguards against oxidative stress, metabolism of polyunsaturated fatty acids, regulation of normal immune response, post-transcriptional regulation, cellular maintenance and markers of longevity were significantly activated in the active duty participants with recent PTSD. In contrast, we observed significantly altered multimodal molecular signatures associated with chronic inflammation, neurodegeneration, cardiovascular and metabolic disorders, and cellular attritions in the veterans with chronic PTSD. Activation status of signaling and metabolic pathways at the early and late timepoints of PTSD demonstrated the differential molecular changes related to homeostatic processes at its recent and multi-system syndromes at its chronic phase. Molecular alterations in the recent PTSD seem to indicate some sort of recalibration or compensatory response, possibly directed in mitigating the pathological trajectory of the disorder.

Newly developed sarcopenia after liver transplantation, determined by a fully automated 3D muscle volume estimation on abdominal CT, can predict post-transplant diabetes mellitus and poor survival outcomes

BACKGROUND

Loss of muscle mass is the most common complication of end-stage liver disease and negatively affects outcomes for liver transplantation (LT) recipients. We aimed to determine the prognostic value of a fully automated three-dimensional (3D) muscle volume estimation using deep learning algorithms on abdominal CT in patients who underwent liver transplantation (LT).

METHODS

This retrospective study included 107 patients who underwent LT from 2014 to 2015. Serial CT scans, including pre-LT and 1- and 2-year follow-ups were performed. From the CT scans, deep learning-based automated body composition segmentation software was used to calculate muscle volumes in 3D. Sarcopenia was calculated by dividing average skeletal muscle area by height squared. Newly developed-(ND) sarcopenia was defined as the onset of sarcopenia 1 or 2 years after LT in patients without a history of sarcopenia before LT. Patients' clinical characteristics, including post-transplant diabetes mellitus (PTDM) and Model for end-stage liver disease score, were compared according to the presence or absence of sarcopenia after LT. A subgroup analysis was performed in the post-LT sarcopenic group. The Kaplan-Meier method was used for overall survival (OS).

RESULTS

Patients with ND-sarcopenia had poorer OS than those who did not (P = 0.04, hazard ratio [HR], 3.34; 95% confidence interval [CI] 1.05 - 10.7). In the subgroup analysis for post-LT sarcopenia (n = 94), 34 patients (36.2%) had ND-sarcopenia. Patients with ND-sarcopenia had significantly worse OS (P = 0.002, HR 7.12; 95% CI 2.00 - 25.32) and higher PTDM occurrence rates (P = 0.02, HR 4.93; 95% CI 1.18 - 20.54) than those with sarcopenia prior to LT.

CONCLUSION

ND-sarcopenia determined by muscle volume on abdominal CT can predict poor survival outcomes and the occurrence of PTDM for LT recipients.

T-BET and EOMES sustain mature human NK cell identity and antitumor function

Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity.

Exploiting an Interleukin-15 Heterodimeric Agonist (N803) for Effective Immunotherapy of Solid Malignancies

Identifying effective immunotherapies for solid tumors remains challenging despite the significant clinical responses observed in subsets of patients treated with immune checkpoint inhibitors. Interleukin-15 (IL-15) is a promising cytokine for the treatment of cancer as it stimulates NK and CD8⁺ lymphocytes. However, unfavorable pharmacokinetics and safety concerns render recombinant IL-15 (rIL-15) a less attractive modality. These shortcomings were addressed by the clinical development of heterodimeric IL-15 agonists, including N803. In preclinical tumor models, N803 elicited significant Th1 immune activation and tumor suppressive effects, primarily mediated by NK and CD8⁺ T lymphocytes. In addition, multiple clinical studies have demonstrated N803 to be safe for the treatment of cancer patients. The combination of N803 with the immune checkpoint inhibitor nivolumab demonstrated encouraging clinical responses in nivolumab-naïve and nivolumab-refractory patients with non-small cell lung cancer. In a recent Phase II/III clinical study, most Bacillus Calmette-Guerin (BCG)-refractory bladder cancer patients treated with N803 plus BCG experienced durable complete responses. Currently, N803 is being evaluated preclinically and clinically in combination with various agents, including chemotherapeutics, immune checkpoint inhibitors, vaccines, and other immuno-oncology agents. This report will review the mechanism(s) of action of N803 and how it relates to the preclinical and clinical studies of N803.

Immunomodulatory Function of Interleukin-15 and Its Role in Exercise, Immunotherapy, and Cancer Outcomes

Exercise has been shown to improve physical and psychosocial outcomes for people across the cancer care continuum. A proposed mechanism underpinning the relationship between exercise and cancer outcomes is exercise-induced immunomodulation via secretion of anti-inflammatory myokines from skeletal muscle tissue. Myokines have the potential to impair cancer growth through modulation of natural killer (NK) cells and CD8+ T cells while improving the effectiveness of cancer therapies. Interleukin-15 (IL-15), one of the most abundant myokines found in skeletal muscle, has a key immunoregulatory role in supporting the proliferation and maturation of T cells and NK cells, which have a key role in the host's immune response to cancer. Furthermore, IL-15 is being explored clinically as an immunotherapy agent with doses similar to the IL-15 concentrations released by skeletal muscle during exercise. Here we review the role of IL-15 within the immune system, examine how IL-15 is produced as a myokine during exercise, and how it may improve outcomes for people with cancer, specifically as an adjuvant or neoadjuvant to immunotherapy. We summarize the available evidence showing changes in IL-15 in response to both acute exercise and training, and the results are inconsistent; higher quality research is needed to advance the understanding of how exercise-mediated increases in IL-15 potentially benefit those who are being treated for, or who have had, cancer.

Acid-switchable nanoparticles induce self-adaptive aggregation for enhancing antitumor immunity of natural killer cells

Deficiency of natural killer (NK) cells shows a significant impact on tumor progression and failure of immunotherapy. It is highly desirable to boost NK cell immunity by upregulating active receptors and relieving the immunosuppressive tumor microenvironment. Unfortunately, mobilization of NK cells is hampered by poor accumulation and short retention of drugs in tumors, thus declining antitumor efficiency. Herein, we develop an acid-switchable nanoparticle with self-adaptive aggregation property for co-delivering galunisertib and interleukin 15 (IL-15). The nanoparticles induce morphology switch by a decomposition-metal coordination cascade reaction, which provides a new methodology to trigger aggregation. It shows self-adaptive size-enlargement upon acidity, thus improving drug retention in tumor to over 120 h. The diameter of agglomerates is increased and drug release is effectively promoted following reduced pH values. The nanoparticles activate both NK cell and CD8⁺ T cell immunity in vivo. It significantly suppresses CT26 tumor in immune-deficient BALB/c mice, and the efficiency is further improved in immunocompetent mice, indicating that the nanoparticles can not only boost innate NK cell immunity but also adaptive T cell immunity. The approach reported here provides an innovative strategy to improve drug retention in tumors, which will enhance cancer immunotherapy by boosting NK cells.

TLR5 agonists enhance anti-tumor immunity and overcome resistance to immune checkpoint therapy

Primary and adaptive resistance to immune checkpoint therapies (ICT) represent a considerable obstacle to achieving enhanced overall survival. Innate immune activators have been actively pursued for their antitumor potential. Herein we report that a syngeneic 4T1 mammary carcinoma murine model for established highly-refractory triple negative breast cancer showed enhanced survival when treated intra-tumorally with either the TLR5 agonist flagellin or CBLB502, a flagellin derivative, in combination with antibodies targeting CTLA-4 and PD-1. Long-term survivor mice showed immunologic memory upon tumor re-challenge and a distinctive immune activating cytokine profile that engaged both innate and adaptive immunity. Low serum levels of G-CSF and CXCL5 (as well as high IL-15) were candidate predictive biomarkers correlating with enhanced survival. CBLB502-induced enhancement of ICT was also observed in poorly immunogenic B16-F10 melanoma tumors. Combination immune checkpoint therapy plus TLR5 agonists may offer a new therapeutic strategy to treat ICT-refractory solid tumors.

Improving NK cell function in multiple myeloma with NKTR-255, a novel polymer-conjugated human IL-15

Multiple myeloma (MM) is characterized by an immunosuppressive microenvironment that enables tumor development. One of the mechanisms of immune evasion used by MM cells is the inhibition of natural killer (NK) cell effector functions; thus, the restoration of NK cell antitumor activity represents a key goal to increase tumor cell recognition, avoid tumor escape and potentially enhancing the effect of other drugs. In this study, we evaluated the ability of the investigational medicine NKTR-255, an IL-15 receptor agonist, to engage the IL-15 pathway and stimulate NK cells against MM cells. We observed that incubation with NKTR-255 was able to tilt the balance toward an activated phenotype in NK cells isolated from peripheral blood mononuclear cells of patients with MM, with increased expression of activating receptors on the surface of treated NK cells. This resulted in an enhanced degranulation, cytokine release, and anti-tumor cytotoxicity when the NK cells were exposed to both MM cell lines and primary MM cells. We further evaluated the in vivo effect of NKTR-255 in fully humanized immunocompetent mice subcutaneously engrafted with H929 MM cells. Compared with placebo, weekly injection of the mice with NKTR-255 increased the number of circulating NK cells in peripheral blood and delayed tumor growth. Finally, we observed that combination of NKTR-255 with the anti-CD38 antibody, daratumumab, was effective against MM cells in vitro and in vivo. Taken together, our data suggest a significant impact of NKTR-255 in inducing NK cell function against MM cells with important translational implications.

Establishment of Epithelial Inflammatory Injury Model Using Intestinal Organoid Cultures

Intestinal epithelial dysfunction is critical in the development of inflammatory bowel disease (IBD). However, most cellular experiments related to epithelial barrier studies in IBD have been based on tumor cell line that lack a variety of intestinal epithelial cell types. Thus, intestinal organoids can present the three-dimensional structure and better simulate the physiological structure and function of the intestinal epithelium in vitro. Here, the crypts were isolated from the small intestine of mice; with the participation of major cytokines (EGF, Noggin, and R-Spondin 1 included), the intestinal organoids were established at a density of 100 crypts per well, containing intestinal stem cells (ISC), Paneth cells, goblet cells, and intestinal endocrine cells. We found that tumor necrosis factor-alpha (TNF-α) could induce the inflammatory response of intestinal organoids, and a dose of 10 ng/mL could maintain stable passaging of organoids for dynamic observation. After stimulation with TNF-α, the intestinal organoid cultures showed lower expression of the cell proliferation-related protein identified by monoclonal antibody Ki 67 (Ki67), the ISC marker leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5), and the intestinal tight junction proteins occludin (Ocln) and claudin-1 (Cldn1) while higher expression of the inflammatory cytokine interleukin- (IL-) 15 and the chemokines C-X-C motif ligand 2 (Cxcl2) and Cxcl10 significantly. In this study, we successfully established an epithelial inflammatory injury model of intestinal organoids, which provides an effective in vitro model for studying the pathogenesis and treatment of IBD.

The Cytokine Network in Colorectal Cancer: Implications for New Treatment Strategies

Colorectal cancer (CRC) is one of the most frequent tumor entities worldwide with only limited therapeutic options. CRC is not only a genetic disease with several mutations in specific oncogenes and/or tumor suppressor genes such as APC, KRAS, PIC3CA, BRAF, SMAD4 or TP53 but also a multifactorial disease including environmental factors. Cancer cells communicate with their environment mostly via soluble factors such as cytokines, chemokines or growth factors to generate a favorable tumor microenvironment (TME). The TME, a heterogeneous population of differentiated and progenitor cells, plays a critical role in regulating tumor development, growth, invasion, metastasis and therapy resistance. In this context, cytokines from cancer cells and cells of the TME influence each other, eliciting an inflammatory milieu that can either enhance or suppress tumor growth and metastasis. Additionally, several lines of evidence exist that the composition of the microbiota regulates inflammatory processes, controlled by cytokine secretion, that play a role in carcinogenesis and tumor progression. In this review, we discuss the cytokine networks between cancer cells and the TME and microbiome in colorectal cancer and the related treatment strategies, with the goal to discuss cytokine-mediated strategies that could overcome the common therapeutic resistance of CRC tumors.

Impact of IL-15 and latency reversing agent combinations in the reactivation and NK cell-mediated suppression of the HIV reservoir

Inhibitors of histone deacetylases (HDACis) are major latency reversing agent (LRA) candidates in 'shock and kill' strategies to eradicate the HIV reservoir in infected patients. The poor achievements of initial HDACi-based trials and subsequent studies have highlighted the need for more efficient approaches such as combinatory and immunostimulating therapies. Here we studied combinations of IL-15 with pan-HDACi (Vorinostat, Romidepsin, Panobinostat) or class I selective-HDACi (Entinostat) with or without a PKC agonist (Prostratin) for their impact on in vitro reactivation and NK cell-mediated suppression of latent HIV. Results showed that pan-HDACis but not Entinostat reduced NK cell viability and function; yet, combined IL-15 reverted the negative effects of pan-HDACis except for Panobinostat. All HDACis were ineffective at reactivating HIV in a CD4⁺ T cell model of latency, with pan-HDACis suppressing spontaneous and IL-15- or Prostratin-induced HIV release, while IL-15 + Prostratin combination showed maximal activity. Moreover, Panobinostat impaired STAT5 and NF-κB activation by IL-15 and Prostratin, respectively. Finally, by using effectors (NK) and targets (latently infected CD4⁺ T cells) equally exposed to drug combinations, we found that IL-15-mediated suppression of HIV reactivation by NK cells was inhibited by Panobinostat. Our data raise concerns and encouragements for therapeutic application of IL-15/LRA combinations.

The implications of IL-15 trans-presentation on the immune response

Interleukin-15 is a pleiotropic cytokine type I four alpha-helical bundle cytokine that along with IL-2, IL-4, IL-7, IL-9, and IL-21 shares the common cytokine receptor γ chain, γ_c. IL-15 is vital for the development, survival, and expansion of natural killer cells and for the development of CD8⁺ memory T cells. Whereas other family γ_c cytokines signal by directly binding to their target cells, IL-15 is distinctive in that it binds to IL-15Rα, a sushi domain containing binding protein that is expressed on a number of cell types, including monocytes and dendritic cells as well as T cells, and then is trans-presented to responding cells that express IL-2Rβ and γ_c. This distinctive mechanism for IL-15 relates to its role in signaling in the context of cell-cell interactions and signaling synapses. The actions of IL-15 and ways of manipulating its actions to potential therapeutic benefit are discussed.

Harnessing IL-15 signaling to potentiate NK cell-mediated cancer immunotherapy

Natural killer (NK) cells, a crucial component of the innate immune system, have long been of clinical interest for their antitumor properties. Almost every aspect of NK cell immunity is regulated by interleukin-15 (IL-15), a cytokine in the common γ-chain family. Several current clinical trials are using IL-15 or its analogs to treat various cancers. Moreover, NK cells are being genetically modified to produce membrane-bound or secretory IL-15. Here, we discuss the key role of IL-15 signaling in NK cell immunity and provide an up-to-date overview of IL-15 in NK cell therapy.

An overview of JAK/STAT pathways and JAK inhibition in alopecia areata

Alopecia Areata (AA) is a common autoimmune disease characterized by non-scarring hair loss ranging from patches on the scalp to complete hair loss involving the entire body. Disease onset is hypothesized to follow the collapse of immune privilege of the hair follicle, which results in an increase in self-peptide/MHC expression along the follicular epithelium. Hair loss is associated with infiltration of the hair follicle with putatively self-reactive T cells. This process is thought to skew the hair follicle microenvironment away from a typically homeostatic immune state towards one of active inflammation. This imbalance is mediated in part by the dominating presence of specific cytokines. While interferon-γ (IFNγ) has been identified as the key player in AA pathogenesis, many other cytokines have also been shown to play pivotal roles. Mechanistic studies in animal models have highlighted the contribution of common gamma chain (γ_c) cytokines such as IL-2, IL-7, and IL-15 in augmenting disease. IFNγ and γ_c cytokines signal through pathways involving receptor activation of Janus kinases (JAKs) and signal transducers and activators of transcription (STATs). Based on these findings, JAK/STAT pathways have been targeted for the purposes of therapeutic intervention in the clinical setting. Case reports and series have described use of small molecule JAK inhibitors leading to hair regrowth among AA patients. Furthermore, emerging clinical trial results show great promise and position JAK inhibitors as a treatment strategy for patients with severe or recalcitrant disease. Demonstrated efficacy from large-scale clinical trials of the JAK inhibitor baricitinib led to the first-in-disease FDA-approved treatment for AA in June of 2022. This review aims to highlight the JAK/STAT signaling pathways of various cytokines involved in AA and how targeting those pathways may impact disease outcomes in both laboratory and clinical settings.

Innate lymphoid cells in early tumor development

Innate and adaptive immune cells monitor, recognize, and eliminate transformed cells. Innate lymphoid cells (ILCs) are innate counterparts of T cells that play a key role in many facets of the immune response and have a profound impact on disease states, including cancer. ILCs regulate immune responses by responding and integrating a wide range of signals within the local microenvironment. As primarily tissue-resident cells, ILCs are ideally suited to sense malignant transformation and initiate anti-tumor immunity. However, as ILCs have been associated with anti-tumor and pro-tumor activities in established tumors, they could potentially have dual functions during carcinogenesis by promoting or suppressing the malignant outgrowth of premalignant lesions. Here we discuss emerging evidence that shows that ILCs can impact early tumor development by regulating immune responses against transformed cells, as well as the environmental cues that potentially induce ILC activation in premalignant lesions.

Phospho-proteomics reveals that RSK signaling is required for proliferation of natural killer cells stimulated with IL-2 or IL-15

Natural killer (NK) cells are cytotoxic lymphocytes that play a critical role in the innate immune system. Although cytokine signaling is crucial for the development, expansion, and cytotoxicity of NK cells, the signaling pathways stimulated by cytokines are not well understood. Here, we sought to compare the early signaling dynamics induced by the cytokines interleukin (IL)-2 and IL-15 using liquid chromatography-mass spectrometry (LC-MS)-based phospho-proteomics. Following stimulation of the immortalized NK cell line NK-92 with IL-2 or IL-15 for 5, 10, 15, or 30 min, we identified 8,692 phospho-peptides from 3,023 proteins. Comparing the kinetic profiles of 3,619 fully quantified phospho-peptides, we found that IL-2 and IL-15 induced highly similar signaling in NK-92 cells. Among the IL-2/IL-15-regulated phospho-peptides were both well-known signaling events like the JAK/STAT pathway and novel signaling events with potential functional significance including LCP1 pSer5, STMN1 pSer25, CHEK1 pSer286, STIM1 pSer608, and VDAC1 pSer104. Using bioinformatic approaches, we sought to identify kinases regulated by IL-2/IL-15 stimulation and found that the p90 ribosomal S6 kinase (p90RSK) family was activated by both cytokines. Using pharmacological inhibitors, we then discovered that RSK signaling is required for IL-2 and IL-15-induced proliferation in NK-92 cells. Taken together, our analysis represents the first phospho-proteomic characterization of cytokine signaling in NK cells and increases our understanding of how cytokine signaling regulates NK cell function.

Molecular Signature of Neuroinflammation Induced in Cytokine-Stimulated Human Cortical Spheroids

Crucial in the pathogenesis of neurodegenerative diseases is the process of neuroinflammation that is often linked to the pro-inflammatory cytokines Tumor necrosis factor alpha (TNFα) and Interleukin-1beta (IL-1β). Human cortical spheroids (hCSs) constitute a valuable tool to study the molecular mechanisms underlying neurological diseases in a complex three-dimensional context. We recently designed a protocol to generate hCSs comprising all major brain cell types. Here we stimulate these hCSs for three time periods with TNFα and with IL-1β. Transcriptomic analysis reveals that the main process induced in the TNFα- as well as in the IL-1β-stimulated hCSs is neuroinflammation. Central in the neuroinflammatory response are endothelial cells, microglia and astrocytes, and dysregulated genes encoding cytokines, chemokines and their receptors, and downstream NFκB- and STAT-pathway components. Furthermore, we observe sets of neuroinflammation-related genes that are specifically modulated in the TNFα-stimulated and in the IL-1β-stimulated hCSs. Together, our results help to molecularly understand human neuroinflammation and thus a key mechanism of neurodegeneration.

A novel fusion protein scaffold 18/12/TxM activates the IL-12, IL-15, and IL-18 receptors to induce human memory-like natural killer cells

Natural killer (NK) cells are cytotoxic innate lymphoid cells that are emerging as a cellular immunotherapy for various malignancies. NK cells are particularly dependent on interleukin (IL)-15 for their survival, proliferation, and cytotoxic function. NK cells differentiate into memory-like cells with enhanced effector function after a brief activation with IL-12, IL-15, and IL-18. N-803 is an IL-15 superagonist composed of an IL-15 mutant (IL-15N72D) bound to the sushi domain of IL-15Rα fused to the Fc region of IgG1, which results in physiological trans-presentation of IL-15. Here, we describe the creation of a novel triple-cytokine fusion molecule, 18/12/TxM, using the N-803 scaffold fused to IL-18 via the IL-15N72D domain and linked to a heteromeric single-chain IL-12 p70 by the sushi domain of the IL-15Rα. This molecule displays trispecific cytokine activity through its binding and signaling through the individual cytokine receptors. Compared with activation with the individual cytokines, 18/12/TxM induces similar short-term activation and memory-like differentiation of NK cells on both the transcriptional and protein level and identical in vitro and in vivo anti-tumor activity. Thus, N-803 can be modified as a functional scaffold for the creation of cytokine immunotherapies with multiple receptor specificities to activate NK cells for adoptive cellular therapy.

IL-1R8 silencing improves the anti-tumor function of freshly isolated human NK cells

The inhibitory receptor interleukin-1 receptor 8 (IL-1R8) has been recently recognized to be expressed also by human natural killer (NK) cells. This study was aimed to design and optimize IL-1R8 silencing conditions in human NK cells to precisely establish the activity of such receptor in these cells. Electroporation of freshly isolated or IL-2-cultured NK cells with small interfering RNA (siRNA), resulted in a marked, even though variable, IL-1R8-silencing. Although the expression profile revealed downregulation of most genes involved in several intracellular pathways, some genes related to proliferation, expression of some chemokine receptors, antibody-dependent cell cytotoxicity and cytotoxic activity were upregulated in IL-1R8-silenced NK cells. Furthermore, upon IL-15 activation, the majority of genes involved in NK cell function were upregulated in IL-1R8-siRNA—compared with control—siRNA-transfected NK cells. More importantly, in agreement with these findings, the reduction of IL-1R8 gene expression levels resulted in enhanced expression of NK cell activation markers, production of cytokines and chemokines, and cytotoxic activity against several NK cell targets with different susceptibility to NK-mediated lysis. Similar results were obtained following stimulation with IL-18. All together these data, deeply impacting on the main effector functions of human NK cells, can lead to a better understanding of IL-1R8-mediated regulation on these cells and to the design of new strategies for improving NK cell-mediated anti-tumor responses.

PDGF-D-PDGFRβ signaling enhances IL-15-mediated human natural killer cell survival

Natural killer (NK) cells belong to a critical innate arm of host immunity against viral infection and malignancies. However, limited expansion and persistence of NK cells in vivo remain major challenges for NK cell-based therapy. Here, we show that platelet-derived growth factor (PDGF)-D−PDGF receptor-beta signaling—a potent stimulator of cell growth and motility—activates NK cells in an autocrine manner and contributes to interleukin-15–mediated NK cell survival but not effector functions, the latter of which were previously shown to depend on the binding of PDGF-D to the NKp44 receptor. Therefore, selectively introducing PDGF signaling into NK cells should benefit NK cell expansion and persistence and/or enhance effector function in NK cell-based immunotherapies.

The axis of platelet-derived growth factor (PDGF) and PDGF receptor-beta (PDGFRβ) plays prominent roles in cell growth and motility. In addition, PDGF-D enhances human natural killer (NK) cell effector functions when binding to the NKp44 receptor. Here, we report an additional but previously unknown role of PDGF-D, whereby it mediates interleukin-15 (IL-15)–induced human NK cell survival but not effector functions via its binding to PDGFRβ but independent of its binding to NKp44. Resting NK cells express no PDGFRβ and only a low level of PDGF-D, but both are significantly up-regulated by IL-15, via the nuclear factor κB signaling pathway, to promote cell survival in an autocrine manner. Both ectopic and IL-15–induced expression of PDGFRβ improves NK cell survival in response to treatment with PDGF-D. Our results suggest that the PDGF-D−PDGFRβ signaling pathway is a mechanism by which IL-15 selectively regulates the survival of human NK cells without modulating their effector functions.

IFN-γ Induces IL-15 Trans-Presentation by Epithelial Cells via IRF1

IL-15 exhibits pleiotropic effects on NK and CD8⁺ T cells and contributes to host protection or immunopathology during infection. Although both type I IFNs and IFN-γ upregulate IL-15 expression, their effects on IL-15 upregulation and underlying mechanisms have not been compared comprehensively. In addition, little is known about trans-presentation of IL-15 by epithelial cells to lymphocytes. In this study, we analyzed the expression of IL-15 and IL-15Rα in the human hepatocyte-derived Huh-7 cell line after stimulation with IFN-α, IFN-β, or IFN-γ using RT-PCR, flow cytometry, and confocal microscopy. We also performed knockdown experiments to investigate the signaling pathway involved in IL-15 upregulation. IFN-γ more potently upregulated IL-15 expression in Huh-7 cells than IFN-α and IFN-β. Knockdown experiments revealed that IFN-γ- and IFN-β-induced IL-15 expression relied on IFN regulatory factor 1 (IRF1), which is upregulated by STAT1 and IFN-stimulated gene factor 3, respectively. Inhibitor of κB kinase α/β was also involved in IFN-γ-induced upregulation of IL-15. Furthermore, human NK cells were activated by coculture with IFN-γ-treated Huh-7 cells, which was abrogated by knocking down IL-15Rα in IFN-γ-treated Huh-7 cells, indicating that IFN-γ-induced IL-15 on Huh-7 cells activates NK cells via trans-presentation. In summary, our data demonstrate that IFN-γ potently elicits IL-15 trans-presentation by epithelial cells via IRF1. These data also suggest that the IFN-γ-IRF1-IL-15 axis may be a regulatory target for the treatment of diseases with IL-15 dysregulation.

Single-cell approaches to dissect adaptive immune responses involved in autoimmunity: the case of celiac disease

Single-cell analysis is a powerful technology that has found widespread use in recent years. For diseases with involvement of adaptive immunity, single-cell analysis of antigen-specific T cells and B cells is particularly informative. In autoimmune diseases, the adaptive immune system is obviously at play, yet the ability to identify the culprit T and B cells recognizing disease-relevant antigen can be difficult. Celiac disease, a widespread disorder with autoimmune components, is unique in that disease-relevant antigens for both T cells and B cells are well defined. Furthermore, the celiac disease gut lesion is readily accessible allowing for sampling of tissue-resident cells. Thus, disease-relevant T cells and B cells from the gut and blood can be studied at the level of single cells. Here we review single-cell studies providing information on such adaptive immune cells and outline some future perspectives in the area of single-cell analysis in autoimmune diseases.

Systemic Interleukins' Profile in Early and Advanced Colorectal Cancer

Tumor microenvironment (TME) is characterized by mutual interactions of the tumor, stromal and immune cells. Early and advanced colorectal tumors differ in structure and present altered serum cytokine levels. Mutual crosstalk among TME infiltrating cells may shift the balance into immune suppressive or pro-inflammatory, antitumor response this way influencing patients' prognosis. Cancer-related inflammation affects all the body and this way, the systemic level of cytokines could reflect TME processes. Despite numerous studies, it is still not known how systemic cytokines levels change during colorectal cancer (CRC) tumor development. Better understanding tumor microenvironment processes could help in planning therapeutic interventions and more accurate patient prognosis. To contribute to the comprehension of these processes within TME, we reviewed cytokines levels from clinical trials in early and advanced colorectal cancer. Presented data were analyzed in the context of experimental studies and studies analyzing tumor infiltration with immune cells. The review summarizes clinical data of cytokines secreted by tumor microenvironment cells: lymphocytes T helper 1 (Th1), lymphocytes T helper 2 (Th2), lymphocytes T helper 17 (Th17), regulatory T cells (Treg cells), regulatory T cells (Breg cells), M1/M2 macrophages, N1/N2 neutrophils, myeloid-derived suppressor cells (MDSC), dendritic cells (DC), innate lymphoid cells (ILC) natural killer (NK) cells and tumor cells.

Immunogenicity profile in African green monkeys of a vaccine candidate based on a mutated form of human Interleukin-15

BACKGROUND

Interleukin (IL)-15 is a proinflammatory T-cell growth factor overexpressed in several autoimmune diseases such as rheumatoid arthritis. Our initial strategy to neutralize the increased levels of IL-15 consisted in a vaccine candidate based on the recombinant modified human IL-15 (mhIL-15) mixed with the alum adjuvant. A previous study in non-human primates Macaca fascicularis has shown that vaccination induces neutralizing antibodies against native IL-15, without affecting animal behavior, clinical status, or the percentage of IL-15-dependent cell populations. However, the mhIL-15 used as an antigen was active in the IL-2-dependent cytotoxic T-cell line CTLL-2, which could hinder its therapeutic application. The current article evaluated the immunogenicity in African green monkeys of a vaccine candidate based on IL-15 mutant D8SQ108S, an inactive form of human IL-15.

RESULTS

IL-15 D8SQ108S was inactive in the CTLL-2 bioassay but was able to competitively inhibit the biological activity of human IL-15. Immunization with 200 µg of IL-15 mutant combined with alum elicited anti-IL-15 IgG antibodies after the second and third immunizations. The median values of anti-IL-15 antibody titers were slightly higher than those generated in animals immunized with 200 µg of mhIL-15. The highest antibody titers were induced after the third immunization in monkeys vaccinated with 350 µg of IL-15 D8SQ108S. In addition, sera from immunized animals inhibited the biological activity of human IL-15 in CTLL-2 cells. The maximum neutralizing effect was observed after the third immunization in sera of monkeys vaccinated with the highest dose of the IL-15 mutant. These sera also inhibited the proliferative activity of simian IL-15 in the CTLL-2 bioassay and did not affect the IL-2-induced proliferation of the aforementioned T-cell line. Finally, it was observed that vaccination neither affects the animal behavior nor the general clinical parameters of immunized monkeys.

CONCLUSION

Immunization with inactive IL-15 D8SQ108S mixed with alum generated neutralizing antibodies specific for human IL-15 in African green monkeys. Based on this fact, the current vaccine candidate could be more effective than the one based on biologically active mhIL-15 for treating autoimmune disorders involving an uncontrolled overproduction of IL-15.

Chronic IL-15 Stimulation and Impaired mTOR Signaling and Metabolism in Natural Killer Cells During Acute Myeloid Leukemia

Natural Killer (NK) cells are potent anti-leukemic immune effectors. However, they display multiple defects in acute myeloid leukemia (AML) patients leading to reduced anti-tumor potential. Our limited understanding of the mechanisms underlying these defects hampers the development of strategies to restore NK cell potential. Here, we have used a mouse model of AML to gain insight into these mechanisms. We found that leukemia progression resulted in NK cell maturation defects and functional alterations. Next, we assessed NK cell cytokine signaling governing their behavior. We showed that NK cells from leukemic mice exhibit constitutive IL-15/mTOR signaling and type I IFN signaling. However, these cells failed to respond to IL-15 stimulation in vitro as illustrated by reduced activation of the mTOR pathway. Moreover, our data suggest that mTOR-mediated metabolic responses were reduced in NK cells from AML-bearing mice. Noteworthy, the reduction of mTOR-mediated activation of NK cells during AML development partially rescued NK cell metabolic and functional defects. Altogether, our data strongly suggest that NK cells from leukemic mice are metabolically and functionally exhausted as a result of a chronic cytokine activation, at least partially IL-15/mTOR signaling. NK cells from AML patients also displayed reduced IL-2/15Rβ expression and showed cues of reduced metabolic response to IL-15 stimulation in vitro, suggesting that a similar mechanism might occur in AML patients. Our study pinpoints the dysregulation of cytokine stimulation pathways as a new mechanism leading to NK cell defects in AML.

IL-15 Trans-Presentation Is an Autonomous, Antigen-Independent Process

IL-15 plays a pivotal role in the long-term survival of T cells and immunological memory. Its receptor consists of three subunits (IL-15Rα, IL-2/15Rβ, and γ_c). IL-15 functions mainly via trans-presentation (TP), during which an APC expressing IL-15 bound to IL-15Rα presents the ligand to the βγ_c receptor-heterodimer on a neighboring T/NK cell. To date, no direct biophysical evidence for the intercellular assembly of the IL-15R heterotrimer exists. Ag presentation (AP), the initial step of T cell activation, is also based on APC-T cell interaction. We were compelled to ask whether AP has any effect on IL-15 TP or whether they are independent processes. In our human Raji B cell-Jurkat T cell model system, we monitored inter-/intracellular protein interactions upon formation of IL-15 TP and AP receptor complexes by Förster resonance energy transfer measurements. We detected enrichment of IL-15Rα and IL-2/15Rβ at the synapse and positive Förster resonance energy transfer efficiency if Raji cells were pretreated with IL-15, giving direct biophysical evidence for IL-15 TP. IL-15Rα and MHC class II interacted and translocated jointly to the immunological synapse when either ligand was present, whereas IL-2/15Rβ and CD3 moved independently of each other. IL-15 TP initiated STAT5 phosphorylation in Jurkat cells, which was not further enhanced by AP. Conversely, IL-15 treatment slightly attenuated Ag-induced phosphorylation of the CD3ζ chain. Our studies prove that in our model system, IL-15 TP and AP can occur independently, and although AP enhances IL-15R assembly, it has no significant effect on IL-15 signaling during TP. Thus, IL-15 TP can be considered an autonomous, Ag-independent process.

The Landscape of Immune Cells Indicates Prognosis and Applicability of Checkpoint Therapy in Hepatocellular Carcinoma

Background

Tumor-infiltrating immune cells are important components of tumor microenvironment (TME), and their composition reflects the confrontation between host immune system and tumor cells. However, the relationship between the composition of infiltrating immune cells, prognosis, and the applicability of anti-PD-1/PD-L1 therapy in hepatocellular carcinoma (HCC) needs systematic examination.

Methods

Cell-Type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) was applied to evaluate the infiltration of immune cells based on The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma (LIHC) cohort. Diagnostic and prognostic models were constructed based on immune cells, and the models were validated by two external cohorts. The relationship between immune cells and PD-L1 was evaluated by Spearman correlation, and the finding was validated in our in-house HCC sample.

Result

Patients in TCGA LIHC cohort were classified into six subtypes with different prognosis based on the proportion of tumor-infiltrating immune cells simulated via CIBERSORT. Among 22 types of immune cells, intratumoral PD-L1 mRNA level exhibited linear relationship with the fraction of five types of immune cells (M1 macrophages, plasma cells, CD8⁺ T cells, resting mast cells, and regulatory T cells), and M1 macrophages showed the strongest relevance (R = 0.26, p < 0.001). Immunohistochemistry of our in-house HCC specimens verified this conclusion. Moreover, intratumoral mRNA levels of M1 macrophage-associated cytokines were positively correlated with PD-L1 level.

Conclusions

Our study demonstrated that the prognosis of HCC patients was associated with the pattern of infiltrating immune cells in TME, and macrophage-associated cytokines might be a potential non-invasive marker for predicting the PD-L1 level for HCC patients.

Interleukin-15 in Outcomes of Pregnancy

Interleukin-15 (IL-15) is a pleiotropic cytokine that classically acts to support the development, maintenance, and function of killer lymphocytes. IL-15 is abundant in the uterus prior to and during pregnancy, but it is subject to tight spatial and temporal regulation. Both mouse models and human studies suggest that homeostasis of IL-15 is essential for healthy pregnancy. Dysregulation of IL-15 is associated with adverse outcomes of pregnancy. Herein, we review producers of IL-15 and responders to IL-15, including non-traditional responders in the maternal uterus and fetal placenta. We also review regulation of IL-15 at the maternal-fetal interface and propose mechanisms of action of IL-15 to facilitate additional study of this critical cytokine in the context of pregnancy.

Transcription factor Zhx2 restricts NK cell maturation and suppresses their antitumor immunity

The maturation and functional competence of natural killer (NK) cells is a tightly controlled process that relies on transcription factors (TFs). Here, we identify transcriptional repressor zinc fingers and homeoboxes 2 (Zhx2) as a novel regulator that restricts NK cell maturation and function. Mice with Zhx2 conditional deletion in NK cells (Zhx2Δ/Δ) showed accumulation of matured NK cells. Loss of Zhx2 enhanced NK cell survival and NK cell response to IL-15. Transcriptomic analysis revealed Zeb2, a key TF in NK cell terminal maturation, as a direct downstream target of Zhx2. Therapeutically, transfer of Zhx2-deficient NK cells resulted in inhibition of tumor growth and metastasis in different murine models. Our findings collectively unmask a previously unrecognized role of Zhx2 as a novel negative regulator in NK cell maturation and highlight its therapeutic potential as a promising strategy to enhance NK cell-mediated tumor surveillance.

Therapeutic Potential of IL-15 and N-803 in HIV/SIV Infection

IL-15, a proinflammatory cytokine critical for the generation, maintenance, and homeostasis of T cell responses, is produced naturally in response to HIV/SIV infection, but has also demonstrated therapeutic potential. IL-15 can boost CD4⁺ and CD8⁺ T cell and NK cell proliferation, activation, and function. However, IL-15 treatment may cause aberrant immune activation and accelerated disease progression in certain circumstances. Moreover, the relationship between the timing of IL-15 administration and disease progression remains unclear. The IL-15 superagonist N-803 was developed to expand the therapeutic potential of IL-15 by maximizing its tissue distribution and half-life. N-803 has garnered enthusiasm recently as a way to enhance the innate and cellular immune responses to HIV/SIV by improving CD8⁺ T cell recognition and killing of virus-infected cells and directing immune cells to mucosal sites and lymph nodes, the primary sites of virus replication. N-803 has also been evaluated in “shock and kill” strategies due to its potential to reverse latency (shock) and enhance antiviral immunity (kill). This review examines the current literature about the effects of IL-15 and N-803 on innate and cellular immunity, viral burden, and latency reversal in the context of HIV/SIV, and their therapeutic potential both alone and combined with additional interventions such as antiretroviral therapy (ART) and vaccination.