Interleukin-7 and interleukin-15 as prognostic biomarkers in sepsis and septic shock: Correlation with inflammatory markers and mortality

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and a syndrome shaped by pathogen and host factors evolving over time. During sepsis, the absolute number of lymphocytes decreases. CD4+ and CD8+ T cells, B cells, and NK cells are reduced. Lymphocytes are an essential element of the body's defence against pathogens. Interleukin 7 has strong anti-apoptotic properties and induces the proliferation of CD4+ and CD8+ T lymphocytes. IL-15 prompts the generation of mature NK cells in the bone marrow, plays an important role in the generation, cytotoxicity, and survival of CD8+ T lymphocytes, and is essential for the survival of natural killer T (NKT) and intestinal intraepithelial lymphocytes (IELs). The study highlights the importance of monitoring IL-7 levels in patients with sepsis and septic shock, as low levels of this cytokine were associated with an increased risk of mortality. Physicians should consider using IL-7 levels as a biomarker to identify patients who are at higher risk of mortality and may require more aggressive treatment.

Liver type 1 innate lymphoid cells lacking IL-7 receptor are a native killer cell subset fostered by parenchymal niches

Group 1 innate lymphoid cells (G1-ILCs), including circulating natural killer (NK) cells and tissue-resident type 1 ILCs (ILC1s), are innate immune sentinels critical for responses against infection and cancer. In contrast to relatively uniform NK cells through the body, diverse ILC1 subsets have been characterized across and within tissues in mice, but their developmental and functional heterogeneity remain unsolved. Here, using multimodal in vivo approaches including fate-mapping and targeting of the interleukin 15 (IL-15)-producing microenvironment, we demonstrate that liver parenchymal niches support the development of a cytotoxic ILC1 subset lacking IL-7 receptor (7 R^- ILC1s). During ontogeny, fetal liver (FL) G1-ILCs arise perivascularly and then differentiate into 7 R^- ILC1s within sinusoids. Hepatocyte-derived IL-15 supports parenchymal development of FL G1-ILCs to maintain adult pool of 7 R^- ILC1s. IL-7R⁺ (7R⁺) ILC1s in the liver, candidate precursors for 7 R^- ILC1s, are not essential for 7 R^- ILC1 development in physiological conditions. Functionally, 7 R^- ILC1s exhibit killing activity at steady state through granzyme B expression, which is underpinned by constitutive mTOR activity, unlike NK cells with exogenous stimulation-dependent cytotoxicity. Our study reveals the unique ontogeny and functions of liver-specific ILC1s, providing a detailed interpretation of ILC1 heterogeneity.

Co-expression IL-15 receptor alpha with IL-15 reduces toxicity via limiting IL-15 systemic exposure during CAR-T immunotherapy

Background

Chimeric antigen receptor (CAR)-T cell therapy is a powerful adoptive immunotherapy against both B-cell malignancies and some types of solid tumors. Interleukin (IL) -15 is an important immune stimulator that may provide ideal long-term persistent CAR-T cells. However, higher base line or peak serum IL-15 levels are also related to severe toxicity, such as cytokine release syndrome (CRS), graft-versus-host disease (GVHD), and neurotoxicity.

Methods

We successfully constructed CD19 specific armored CAR-T cells overexpressing IL-I5 and IL-15 receptor alpha (IL-15Ra). In vitro cell differentiation and viability were monitored by flow cytometry, and an in vivo xenograft mouse models was used to evaluate the anti-tumor efficiency and liver damage of CAR-T cells.

Results

CAR-T cells overexpressing IL-15 alone demonstrated enhanced viability, retarded exhaustion in vitro and superior tumor-inhibitory effects in vivo. However, these tumor-free mice had lower survival rates, with serious liver injuries, as a possible result of toxicity. As expected, CAR-T cells overexpressing IL-15 combined with IL-15Ra had reduced CD132 expression and released fewer cytokines (IFNγ, IL-2 and IL-15) in vitro, as well as had the tendency to improve mouse survival via repressing the growth of tumor cells and keeping livers healthier compared to CAR-IL-15 T cells.

Conclusions

These results indicated the importance of IL-15 in enhancing T cells persistence and IL-15Ra in reducing the adverse effects of IL-15, with superior tumor retardation during CAR-T therapy. This study paves the way for the rapid exploitation of IL-15 in adoptive cell therapy in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03626-x.

Enhanced half-life and antitumor activity of Interleukin-15 through genetic fusion of a serum albumin-specific protein binder

Human interleukin-15 (hIL-15) has attracted a considerable attention as a promising cancer immunotherapeutic due to its function to directly stimulate the proliferation and cytotoxic activity of NK and T cells. Nevertheless, a relatively short half-life of hIL-15 requires repeated administration and higher doses, causing serious side effects. Here, we demonstrate an enhanced blood half-life and biological activity of hIL-15 through genetic fusion of a human serum albumin-specific protein binder (rHSA). The fusion construct (rHSA-IL15) was observed to maintain respective binding activities for both hIL-15 receptor α and human serum albumin. The rHSA-IL15 led to a significant increase in the secretion of Granzyme B and INF-γ by immune cells compare to free hIL-15, expanding the population of activated T cell subset such as CD4 ⁺ T and CD8⁺ T cells. The terminal half-life of the rHSA-IL15 was prolonged by around a 40-fold in transgenic mice expressing human serum albumin, compared to free hIL-15. The rHSA-IL15 resulted in distinct anti-tumor activities in xenograft SCC (squamous cell carcinoma) mouse and allograft melanoma mouse models through activation of NK and CD8⁺ T cells. The rHSA-IL15 is expected to be used in cancer immunotherapy, assisting in the development of other cytokines as immunotherapeutic agents with greater efficacy.

Treatment of grade III knee osteoarthritis with bone marrow stimulation and intraarticular injection of triamcinolone and hyaluronic acid combination; three case report and literature review

INTRODUCTION AND IMPORTANCE

Osteoarthritis is a severe joint disease that affects more than 60% of the elderly and more common an idiopathic disease or unknown cause although there is also a secondary cause such as trauma, infection, neurological or metabolic disorders. The usual complaints that perceived by osteoarthritis patients is pain in the affected joint. Many patients and providers think of arthroplasty as the only surgical option for the treatment of osteoarthritis of the knee. However, there are several other surgical options for osteoarthritis which can be therapeutic alternatives. The role of bone marrow stimulation and intraarticular injection with triamcinolone and Hyaluronic acid combination on grade III knee osteoarthritis patient has not been reported.

CASE PRESENTATION

Three patients who presented to orthopedic department with complaints of bilateral knee pain were identified with grade III osteoarthritis (Kellgren and Lawrence) receiving some kind of analgetic treatment for more than 1 year which provided pain relief for some time but not permanent. They underwent arthroscopic procedure (bone marrow stimulation) and then injected with triamcinolone and hyaluronic acid combination. Pre and post operation outcome scores (WOMAC score, Interleukin 15 and MRI) were assessed. At six-month follow-up, all patients reported improvement in pain and stiffness. WOMAC score and Interleukin 15 serum level decreases, MRI with Amadeus score showed improvement of cartilage defect.

CLINICAL DISCUSSION

This case report showed that our three patients were successfully treated with bone marrow stimulation and intraarticular injection with triamcinolone and hyaluronic acid combination. All three patients have improved in their functional outcome, IL 15 and cartilage defect.

CONCLUSION

Bone marrow stimulation and intraarticular injection with triamcinolone and hyaluronic acid combination can be a valuable treatment option for moderate active patients with grade III knee osteoarthritis.

Interleukin 15 participates in Jagged1-induced mineralization in human dental pulp cells

OBJECTIVES

Crosstalk between Notch and other cell signaling molecules has been implicated to regulate the osteogenic differentiation. Understanding the interaction between Notch and IL15 is essential to reveal molecular mechanism. Thus, the objective of the present study was to investigate whether IL15 participates in the Notch signaling-induced mineral deposition in human dental pulp cells (hDPs).

METHODS

hDPs were explanted from dental pulp tissues. To activate Notch signaling, the cells were seeded on Jagged1-immobilized surfaces. The mRNA expression was evaluated using real-time polymerase chain reaction. hDPs were treated with 5-50 ng/mL IL15. Cell viability and proliferation were determined using an MTT assay. Mineral deposition was examined using alizarin red s and Von Kossa staining. In some experiments, the cells were pretreated with a JAK inhibitor prior to stimulation.

RESULTS

Jagged1 induced IL15 and IL15RA expression in hDPs. IL15 treatment significantly increased mineral deposition at 14 d and upregulated ALP, OCN, OSX, ANKH, and ENPP1 mRNA expression. IL15-induced mineralization was attenuated by JAK inhibitor pretreatment. Further, JAK inhibitor pretreatment inhibited the effect of Jagged1 on hDP mineral deposition.

CONCLUSION

IL15 promoted the osteogenic differentiation in hDPs. Moreover, IL15 participated in the Jagged1-induced mineralization in hDPs.

Interleukin 15 and Eotaxin correlate with the outcome of breast cancer patients vice versa independent of CTC status

Background

Circulating tumor cells (CTC) in the peripheral blood in women with breast cancer has been found to be an indicator of prognosis before the start of systemic treatment. The aim of this study is the assessment of specific cytokine profiles as markers for CTC involvement that could act as independent prognostic markers in terms of survival outcome for breast cancer patients.

Methods

Patients selected for this study were defined as women with breast cancer of the SUCCESS study. A total of 200 patients’ sera were included in this study, 100 patients being positive for circulating tumor cells (CTC) and 100 patients being CTC negative. The matching criteria were histo-pathological grading, lymph node metastasis, hormone receptor status, TNM classification, and patient survival. Commercial ELISA with a multi cytokine/chemokine array was used to screen the sera for Interleukin 15 (IL-15) and eotaxin.

Results

Statistically significant concentrations were exposed for IL-15 levels regardless of the CTC-Status, lymph node involvement, or hormone receptor status. Significantly enhanced serum IL-15 concentrations were observed in those patients with worse overall survival (OS) and disease-free survival (DFS). Elevated serum concentrations of IL-15 significantly correlate with patients diagnosed with Grade 3 tumor and worse OS. In contrast, patients with a Grade 3 tumor with a favourable OS and DFS demonstrated significantly decreased IL-15 values. The CTC negative patient subgroup with a favourable OS and DFS, showed statistically significant elevated eotaxin values.

Conclusion

These findings suggest a potential functional interaction of increased IL-15 concentrations in the peripheral blood of patients with a worse OS and DFS, regardless of prognostic factors at primary diagnosis. The increased levels of the chemokine eotaxin in CTC negative patients and a favourable OS and DFS, on the other hand, suggest that the overexpression inhibits CTCs entering the peripheral blood, thus emphasizing a significant inhibition of circulation specific metastasis. To sum up, IL-15 could be used as an independent prognostic marker in terms of survival outcome for breast cancer patients and used as an early indicator to highlight high-risk patients and consequently the adjustment of cancer therapy strategies.

Resistance Exercise in a Hot Environment Alters Serum Markers in Untrained Males

Purpose: We examined the effects of moderate resistance exercise (RE) on serum cortisol, testosterone, extracellular heat shock protein (HSP70), and interleukin (IL)-6 and IL-15 concentrations in untrained males in a hot environment.

Methods: Ten untrained young males (26 ± 3 years; 75.8 ± 6 kg; 177.4 ± 5.3 cm) performed two series of full body RE [3 sets of 8 to 10 repetitions, 30–60 s recovery between series with 70% of one maximal repetition (1-RM), with a rest period of 1 to 3 min between exercises] carried out in a random order in both heated (∼35°C) and thermoneutral (22°C) conditions. Serum concentrations of testosterone, cortisol, HSP70, and IL-6 and IL-15 were measured before, at the end, and 1 h after RE sessions. Participants in both groups consumed 4 ml of water/kg body mass every 15 min.

Results: There were time-related changes in testosterone, HSP70, and IL-6 (P < 0.001), and cortisol and IL-15 (P < 0.05). Levels of cortisol, HSP70, and IL-6 increased immediately for RE at 35°C, and testosterone and IL-15 levels were decreased. Changes in serum testosterone, HSP70, cortisol, and IL-15 and IL-6 levels were reversed after 1 h. A significant time × condition interaction was observed for IL-15 and HSP70 (P < 0.001), cortisol and IL-6 (P < 0.05), but not for testosterone (P > 0.05).

Conclusion: RE in a heated environment may not be appropriate for achieving muscle adaptations due to acute changes of hormonal and inflammatory markers.

IL-15 Expression Pattern in Atopic Dermatitis

BACKGROUND

An increased expression of interleukin (IL)-15, a cytokine with a key role in stimulating innate and adaptive immune cells, such as dendritic cells (DC), natural killer cells, and T cells, has been observed in infectious and inflammatory diseases, including autoimmune diseases as well as cancer. Atopic dermatitis (AD) is a common inflammatory skin disease characterized by a type 2 immune response.

OBJECTIVE

To explore the expression of IL-15 and its pattern in AD skin.

METHOD

Immunofluorescence staining was performed on skin specimens of AD skin, nonlesional AD skin (AD NL), and normal skin (NS) using antibodies directed against IL-15 and CD3, mast cell tryptase, eosinophil cationic protein, CD68, CD11b, CD1a, and vimentin.

RESULTS

A significantly higher IL-15 expression in AD and AD NL was observed in both the epidermis (p = 0.0003) and the dermis (p = 0.0154) as compared to NS. Cells expressing IL-15 were mainly keratinocytes, CD1a+ DC, CD11b+ DC, CD68+ macrophages, and vimentin+ fibroblasts. In AD, an increase in the relative numbers of IL-15 expressing CD1a+ DC, macrophages, and fibroblasts was noted.

CONCLUSION

Our results demonstrate an expression of IL-15 in AD similar to that of eosinophilic esophagitis which is also a type 2 disease. IL-15 may serve as a therapeutic target for AD.

Transformation of Old Concepts for a New Era of Cancer Immunotherapy: Cytokine Therapy and Cancer Vaccines as Combination Partners of PD1/PD-L1 Inhibitors

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICI) are only effective in a subset of patients. Here, we will review the rationale and data supporting the combination of PD-1 pathway inhibition with recombinant cytokines and neoantigen-based cancer vaccines that can potentially increase the number of patients who will benefit from immunotherapy.

RECENT FINDINGS

The safety and tolerability of new interleukin(IL)-2 formulations, IL-15 super agonist, and PEGylated IL-10 have been evaluated in early phase clinical trials with promising efficacy data, both as monotherapy and in combination with ICI. Larger studies focusing on the efficacy of these combinations are ongoing. Personalized neoantigen-based cancer vaccines, enabled by improvements in sequencing computational capabilities, have been proven to be feasible, safe, and able to trigger a consistent vaccine-specific immune response in cancer patients. New pharmacologically modified recombinant cytokines and personalized neoantigen-based vaccines may turn these approaches into powerful tools for effective combination immunotherapy.

hIL-15-gene modified human natural killer cells (NKL-IL15) exhibit anti-human leukemia functions

PURPOSE

Natural killer (NK) cells can kill transformed cells and represent anti-tumor activities for improving the immunotherapy of cancer. In previous works, we established human interleukin-15 (hIL-15) gene-modified NKL cells (NKL-IL15) and demonstrated their efficiency against human hepatocarcinoma cells (HCCs) in vitro and in vivo. To further assess the applicability of NKL-IL15 cells in adoptive cellular immunotherapy for human leukemia, here we report their natural cytotoxicity against leukemia in vitro and in vivo.

METHODS

Flow cytometry, ELISA and MTT methods were performed for molecular expression, cell proliferation and cytotoxicity assays. Leukemia xenograft NOD/SCID mice were established by subcutaneous injection with K562 cells, and then treated with irradiated NKL cells.

RESULTS

We found NKL-IL15 cells displayed a significant high cytolysis activity against both human leukemia cell lines and primary leukemia cells from patients, accompanied with up-regulated expression of molecules related to NK cell cytotoxicity such as perforin, granzyme B and NKp80. Moreover, cytokines secreted by NKL-IL15 cells, including TNF-α and IFN-γ, could induce the expression of NKG2D ligands on target cells, which increased the susceptibility of leukemia cells to NK cell-mediated cytolysis. Encouragingly, NKL-IL15 cells significantly inhibited the growth of leukemia cells in xenografted NOD/SCID mice and prolonged the survival of tumor-bearing mice dramatically. Furthermore, NKL-IL15 cells displayed stimulatory effects on hPBMCs, indicating the immunesuppressive status of leukemia patients could be improved by NKL-IL15 cell treatment.

CONCLUSIONS

These results provided evidence that IL-15 gene-modification could augment NK cell-mediated anti-human leukemia function, which would improve primary NK cell-based immunotherapy for leukemia in future.

Serum interleukin 15 levels in patients with seropositive myasthenia gravis do not correlate with disease severity

AIM

To assess interleukin 15 (IL-15) serum levels in patients with seropositive myasthenia gravis (MG); searching for potential relationship between IL-15 levels and clinical features such as gender, age at onset, clinical presentation or treatment received.

BACKGROUND

IL-15 plays pivotal role in T-cell dependent autoimmunity. Increased IL-15 serum levels have been reported in several autoimmune diseases including MG patients from Japan.

PATIENTS AND METHODS

Sera of 42 seropositive MG patients (66.7% women), mean age 50.6±23.7 years) have been tested by ELISA for IL-15 levels.

RESULTS

There were no statistically significant differences between IL-15 serum levels in MG patients in comparison with controls as well as between subgroups of MG patients (early vs. late onset and thymoma MG). Mean/median IL-15 serum levels were similar in MG patients treated with corticosteroids (CS) and CS naïve. Outliers (very high values) were seen only in untreated generalized MG patients.

CONCLUSIONS

Serum interleukin 15 levels in patients with seropositive myasthenia gravis do not correlate with disease severity.

A novel strategy to produce high level and high purity of bioactive IL15 fusion proteins from mammalian cells

IL15, a member of the common γ chain receptor (γc) cytokine family, is gaining attention in recent years as one of the most promising anti-tumor agents. IL15 regulates T cell activation and proliferation, promotes the survival of CD8⁺ CD44^hi memory T cells and is also essential for NK cell expansion and development. Despite the attraction of developing IL15 as an anti-cancer agent, production of recombinant IL15 has proven to be difficult due to the stringent control of IL15 expression at the transcriptional, translational and the post-translational levels. Furthermore, the bioactivity of IL15 fused to an extra functional domain that is isolated from mammalian cells is generally inferior to recombinant IL15 produced by E. coli. In this study, we report that Lysine 86 in IL15 is responsible for the instability in mammalian cells when its C-terminus is fused to the albumin binding scFv (IL15-A10m3). We demonstrate that K86A or K86R mutants increased the expression of the fusion protein from HEK293 cells. When the wild type IL15 is used for the fusion, no recombinant IL15 fusion was detected in the culture media. Additionally, we determined that the residue 112 in IL15 is critical for the bioactivity of IL15-A10m3. Examination of single and double mutants provides a better understanding of how IL15 engages with its receptor complex to achieve full signaling capacity. The results of our experiments were successfully applied to scale up production to levels up to 50 mg/L and >10 mg/L of >95% pure monomeric recombinant fusion proteins after a 2-step purification from culture media. More importantly, the recombinant fusion protein produced is fully active in stimulating T cell proliferation, when compared to the recombinant wild type IL15.

Modification of NK cell subset repartition and functions in granulocyte colony-stimulating factor-mobilized leukapheresis after expansion with IL-15

The ability of natural killer (NK) cells to kill tumor cells without antigen recognition makes them appealing as an adoptive immunotherapy. However, NK cells are not routinely used in the context of leukemic relapse after hematopoietic stem cell transplantation. Patients who experience relapse can be treated with donor lymphocyte infusions (DLI) based on small-cell fractions frozen at the time of transplantation. Since peripheral blood stem cells (PBSCs) are increasingly used as a stem cell source and as a source of cells for DLI, we aimed to evaluate the impact of G-SCF mobilization on NK cell phenotype, subset repartition, and functionality. Immunomagnetically isolated NK cells from healthy donor blood, donor PBSCs, and patient PBSCs were expanded for 14 days with IL-15. The expansion capacity, phenotype, and functions (cytokine secretion and cytotoxicity) of NK cell subsets based on CD56 and CD16 expression were then evaluated. Mobilized sources showed a significant decrease of CD56^brightCD16⁺ NK cells (28 versus 74%), whereas a significant increase (64 versus 15%) of CD56^brightCD16^- NK cells was observed in comparison with peripheral blood. Patient-mobilized NK cells showed a significantly decreased cytotoxicity, and antibody-dependent cell cytototoxicity (ADCC) was also observed to a lesser extent in NK cells from healthy donor PBSC. G-CSF-mobilized NK cell TNF-α and IFN-γ secretion was impaired at day 0 compared to healthy donors but was progressively restored after culture. In conclusion, expansion of NK cells from G-CSF-mobilized sources may progressively improve their functionality.

IL-15 polymorphisms are associated with subclinical atherosclerosis and cardiovascular risk factors. The Genetics of Atherosclerosis Disease (GEA) Mexican Study

Interleukin IL-15 (IL-15) has been implicated in the development of coronary artery disease (CAD). The aim of the present study was to evaluate the role of IL-15 gene polymorphisms as susceptibility markers for development of subclinical atherosclerosis (SA) and cardiovascular risk factors in Mexican population. Four IL-15 gene polymorphisms (rs4956403, rs3806798, rs1057972 and rs10833) were analyzed in a group of 397 individuals with SA and 1120 controls. Under different inheritance models adjusted by traditional risk factors, the rs10833T allele was associated with increased risk of developing SA [OR=1.42, P_codom1=0.046; OR=1.48, P_dom=0.021; OR=1.43, P_add=0.014]. Under a dominant model, the rs1057972 polymorphism was associated with central obesity (P=0.045) and fatty liver (P=0.021), while the rs10833 polymorphism was associated with metabolic syndrome (P=0.007) in individuals with SA. The TAC haplotype was significantly associated with a decreased risk of SA. Individuals with rs10833CC genotype exhibited higher levels of IL-15 than individuals with CT+TT genotypes. The results suggest that IL-15 polymorphisms are involved in the risk of developing SA and are associated with metabolic syndrome, central obesity and fatty liver in our study population. The rs10833 polymorphism could be involved in regulating IL-15 production in SA.

Whole transcriptome data of primary human NK cells under hypoxia and interleukin 15 priming: A 2×2 factorial design experiment

Natural Killer (NK) cells mediate innate immunity against cancer and intracellular infection, at that, operating in often oxygen-deprived environments. We performed a microarray experiment with a 2×2 factorial design to profile gene expression in human NK cells (Velasquez et al., 2016) [1]. In this experiment, NK cells from 5 healthy volunteers were primed or not for 6 h with the survival factor and inflammatory cytokine interleukin 15 (IL-15) under hypoxic or normoxic culture conditions (20 samples in total). Here, we provide details on the culture setup that govern the actual O₂ partial pressure (pO₂) experienced by the cells, as well as on the RNA extraction procedure used, which we optimized from commercial spin column protocols to obtain highly concentrated total RNA. We present a quality control analysis of the normalized microarray data, as well as overviews for differentially regulated genes. These data provide insights into NK cell transcriptional responses to immune stimulation under physiologically relevant low oxygen conditions. This dataset is deposited in the Gene Expression Omnibus database (accession number GSE70214).

Intravesical ALT-803 for BCG-unresponsive Bladder Cancer - A Case Report

The administration of intravesical chemotherapy or BCG often can prolong the progression-free interval after initial transurethral resection in select bladder cancer (BCa) patients. However, 60% of these patients will recur and up to 30% of patients with recurrent BCa will progress and succumb to their disease over a 15 year period, while another 50% will cystectomy in an attempt to control their disease. Thus better therapeutic strategies are needed for patients who have failed intravesical therapy. In this article, we report the treatment of a 91-year-old man with NMIBC with high-risk features that had failed multiple intravesical therapies.

Interleukin-15 receptor α on hepatic stellate cells regulates hepatic fibrogenesis in mice

BACKGROUND & AIMS

Interleukin-15 (IL-15) and its high affinity receptor interleukin-15 receptor alpha (IL-15Rα) are widely expressed in immune cells and hepatic resident cells. IL-15 signaling has important functions in homeostasis of natural killer (NK), natural killer T (NKT) and cytotoxic T (CD8(+) T) cells, and in liver regeneration. We hypothesized that IL-15 has a protective role in liver fibrosis progression by maintaining NK cell homeostasis.

METHODS

Fibrosis was induced using two mechanistically distinct models. Congenic bone marrow transplantation was used to evaluate the contribution of IL-15 signaling from various compartments to NK, CD8(+) T and NKT cell homeostasis and fibrogenesis. The gene expression profile of hepatic stellate cell (HSC) from IL-15Rα knockout (IL-15RαKO) mice and wild-type mice were captured using microarray analysis and validated in isolated HSC. Quantitative real-time PCR was used to assess repressors of collagen transcription.

RESULTS

IL-15RαKO mice exhibited more fibrosis in both models. IL-15 signaling from specific types of hepatic cells had divergent roles in maintaining liver NK, CD8(+) T and NKT cells, with a direct and protective role on radio-resistant non-parenchymal cells beyond the control of NK homeostasis. HSCs isolated from IL-15RαKO mice demonstrated upregulation of collagen production. Finally, IL-15RαKO HSC with or without transforming growth factor beta (TGF-β) stimulation exhibited increased expression of fibrosis markers and decreased collagen transcription repressors expression.

CONCLUSIONS

IL-15Rα signaling has a direct anti-fibrotic effect independent of preserving NK homeostasis. These findings establish a rationale to further explore the anti-fibrotic potential of enhancing IL-15 signaling in HSCs.

LAY SUMMARY

We investigated how a cellular protein, Interleukin-15 (IL-15), decreases the amount of scar tissue that is formed upon liver injury. We found that IL-15 and its receptor decrease the amount of scar tissue that is created by specialized liver cells (called stellate cells) and increase the number of a specific subgroup of immune cells (natural killer cells) that are known to eliminate stellate cells.

TRANSCRIPT PROFILING ACCESSION NUMBER

GSE45612, GSE 68001 and GSE 25097.

Effects of Eccentric and Concentric Emphasized Resistance Exercise on IL-15 Serum Levels and Its Relation to Inflammatory Markers in Athletes and Non-Athletes

BACKGROUND

Cytokines play an important role in modulating the muscle's metabolic and immunological responses to exercise.

OBJECTIVES

In the present study, we investigated changes in the serum levels of Interleukin (IL)-15 as well as tumor necrosis factor (TNF)-α and high sensitivity C-reactive protein (hs-CRP), as markers of inflammation, in athlete and non-athlete young men following eccentric (ECC) and concentric (CON) emphasized resistance exercise (RE).

PATIENTS AND METHODS

This study recruited 28 young males, 14 athletes and 14 non-athletes. Subjects completed two bouts of ECC and CON emphasized RE five days apart. Each bout included seven exercises that emphasized all major muscle groups with weight loads of 70% - 80% of one repetition maximum (1RM) for CON RE and 90% - 100% of 1RM for ECC RE. We analyzed subjects' blood samples before and immediately after each bout of exercise to determine cytokine and hs-CRP serum levels according to enzyme-linked immunosorbent assay.

RESULTS

Statistical analysis showed a significant difference between IL-15 serum levels before and after ECC and CON RE in non-athletes (P = 0.03). In athletes, IL-15 serum level only increased after ECC RE (P = 0.01), which was noted to be the highest degree of change in IL-15 levels in all subjects. For athletes, the hs-CRP levels significantly decreased (P < 0.05). The serum levels of both TNF-α and hs-CRP were also significantly down-regulated after ECC RE in non-athletes.

CONCLUSIONS

These results indicated that fitness level and RE could modulate circulating levels of IL-15 and suggest the potential anti-inflammatory effects of IL-15 during RE.

Molecular characterization of interleukin 15 mRNA from rohu, Labeo rohita (Hamilton): Its prominent role during parasitic infection as indicated from infection studies

Interleukin 15 (IL-15) is an important cytokine of fish immune system. Sequence characterization of IL-15 from rohu, Labeo rohita revealed a mRNA sequence of 1064 bp with coding sequence of 567 bp and signal peptide of 16 amino acids. There are four characteristic sequence features viz., presence of four out-of-frame AUG initiation codons, four highly conserved cysteine residues, constitutive expression in all tissues and evolutionary similarity. The ontogeny study revealed maternal transfer of this molecule and higher expression up to 3 h post-fertilization in fertilized embryos. Its expression was down-regulated in anterior and posterior kidneys, intestine and liver tissues of rohu infected with Aeromonas hydrophila. Mild up-regulation in liver and higher expression in spleen was noticed in rohu stimulated with poly I:C (poly ionosinic:cytidylic), whereas down-regulation was observed in intestine and kidney tissues. However, a consistent higher expression was noticed in kidney and skin tissues during Argulus siamensis infection. Therefore, rohu IL-15 might possess more defensive role during early development and parasitic infection.

Thymic precursors of TCRαβ(+)CD8αα(+) intraepithelial lymphocytes are negative for CD103

CD5(+)TCRαβ(+) cells in CD4(-)CD8(-) double negative (DN) thymocytes are generally regarded as the thymic precursors of TCRαβ(+)CD8αα(+) intestinal intraepithelial lymphocytes (IELs). However, this population is not homogenous and can be subdivided based on the expression of cell surface markers such as CD103. In this study, we aimed to define a cell population that is enriched in thymic IEL precursors. Here we report that only CD103(-) but not CD103(+)cells in the CD5(+)TCRαβ(+) DN thymocyte population can give rise to TCRαβ(+)CD8αα(+) IELs or IEL-like cells in in vivo injections and in vitro cultures, respectively. In addition, we demonstrate that IL-15 stimulation alone is sufficient for upregulation of CD8αα in CD103(-)CD5(+)TCRαβ(+) DN thymocytes. We also found that the CD103(-)CD5(+)TCRαβ(+) DN population can be further separated into two fractions: CD69(-/lo) and CD69(+). Of these two fractions, only CD69(-/lo) cells can give rise to CD8αα IEL-like cells in the presence of IL-15 in in vitro cultures. Based on these results, we conclude that a CD69(-/lo)CD103(-)CD5(+)TCRαβ(+) DN population is highly enriched in thymic IEL precursors.