Impact of Th1/Th2 cytokine polarity induced by invariant NKT cells on the incidence of pregnancy loss in mice

Bioactivities and Anti-Cancer Activities of NKT-Stimulatory Phenyl-Glycolipid Formulated with a PEGylated Lipid Nanocarrier

Purpose

The glycolipid α-galactosylceramide (α-GalCer), when presented by CD1d, can modulate the immune system through the activation of natural killer T (NKT) cells. Previously, we synthesized over 30 analogs of α-GalCer and identified a compound, C34, which features two phenyl rings on the acyl chain. C34 exhibited the most potent NKT-stimulating activities, characterized by strong Th1-biased cytokines and potent anti-tumor effects in several murine tumor models. Importantly, unlike α-GalCer, C34 did not induce NKT cell anergy. Despite these promising results, the clinical application of C34 is limited by its poor aqueous solubility. PEGylation enhances the solubility of hydrophobic drugs, and numerous PEGylated drugs have received clinical approval. Consequently, we assessed the biological activity of PEGylated C34 in this study.

Methods

Murine NK1.2 cells were cultured with A20-CD1d cells in the presence of either PEGylated lipid nanocarriers encapsulating C34 (PLN-C34) or C34 dissolved in DMSO to determine IL-2 production via ELISA. C57BL/6 mice were i.v. injected with C34 or PLN-C34 to examine cytokine profiles and immune cell populations using luminex and flow cytometry, respectively. The anticancer effects of C34 and PLN-C34 were evaluated in mice bearing TC-1 lung cancer and B16 melanoma tumors. Additionally, human PBMCs were cultured with C34 or PLN-C34 to measure cytokine production through luminex.

Results

PLN-C34 demonstrated a comparable capacity to C34 in activating the NKT cell line in vitro and inducing various cytokines in vivo. Furthermore, treatment with either PLN-C34 or C34 significantly prolonged the survival of TC-1- and B16F10-bearing mice to a similar extent. Additionally, PLN-C34 effectively stimulated cytokine responses in human NKT cells, comparable to those induced by C34.

Conclusion

These findings demonstrate that the newly formulated PLN-C34 retains NKT-stimulatory activity and anti-cancer efficacy of C34, supporting the potential of PLN as a solvent for C34 for further development in cancer therapy.

Evaluation of NKT Cell Percentage and Function and Its Relationship with Serum IFN-γ and Vitamin D Levels in Women with Recurrent Spontaneous Abortion and Recurrent Implantation Failure

Background

Mothers experiencing recurrent spontaneous abortion (RSA) along with repeated implantation failures (RIF) could potentially have abnormalities in their immune systems. Vitamin D is known as a crucial immunomodulatory agent. This study aimed to assess the ratio of Natural Killer T-cells (NKTs) and the correlation between this ratio with serum vitamin D levels among women with RSA and RIF.

Methods

In this research, blood samples were collected from both patients and a group of healthy individuals. The flow cytometry technique was used to determine the proportion of NKT and activated NKT cells. Additionally, Vitamin D and IFN-γ levels were measured using the ELISA technique.

Results

The mean ratio of NKT cells and IFN-γ levels increased significantly in those women with RSA relative to our healthy control group [(P < 0.018) and (p < 0.031), respectively]. Nevertheless, women in the RIF and control groups did not show any significant differences. Serum vitamin D levels significantly decreased in RIF (p < 0.04) and RSA (p < 0.01) groups relative to the control group.

Conclusions

It was found that increasing ratio as well as inflammatory activity of NKT cells correlated with repeated miscarriage. Reduced vitamin D levels could cause immune system disorder along with pregnancy complications.

Role of inflammatory cells in pathophysiology and management of diabetic retinopathy

Diabetic retinopathy (DR) is a sight-threatening complication of diabetes mellitus. Several inflammatory cells and proteins, including macrophages and microglia, cytokines, and vascular endothelial growth factors, are found to play a significant role in the development and progression of DR. Inflammatory cells play a significant role in the earliest changes seen in DR including the breakdown of the blood retinal barrier leading to leakage of blood into the retina. They also have an important role in the pathogenesis of more advanced stage of proliferative diabetic retinopathy, leading to neovascularization, vitreous hemorrhage, and tractional retinal detachment. In this review, we examine the function of numerous inflammatory cells involved in the pathogenesis, progression, and role as a potential therapeutic target in DR. Additionally, we explore the role of inflammation following treatment of DR.

Adjuvants: Engineering Protective Immune Responses in Human and Veterinary Vaccines

Adjuvants are key components of many vaccines, used to enhance the level and breadth of the immune response to a target antigen, thereby enhancing protection from the associated disease. In recent years, advances in our understanding of the innate and adaptive immune systems have allowed for the development of a number of novel adjuvants with differing mechanisms of action. Herein, we review adjuvants currently approved for human and veterinary use, describing their use and proposed mechanisms of action. In addition, we will discuss additional promising adjuvants currently undergoing preclinical and/or clinical testing.

Tissue-resident immunity in the female and male reproductive tract

The conception of how the immune system is organized has been significantly challenged over the last years. It became evident that not all lymphocytes are mobile and recirculate through secondary lymphoid organs. Instead, subsets of immune cells continuously reside in tissues until being reactivated, e.g., by a recurring pathogen or other stimuli. Consequently, the concept of tissue-resident immunity has emerged, and substantial evidence is now available to support its pivotal function in maintaining tissue homeostasis, sensing challenges and providing antimicrobial protection. Surprisingly, insights on tissue-resident immunity in the barrier tissues of the female reproductive tract are sparse and only slowly emerging. The need for protection from vaginal and amniotic infections, the uniqueness of periodic tissue shedding and renewal of the endometrial barrier tissue, and the demand for a tailored decidual immune adaptation during pregnancy highlight that tissue-resident immunity may play a crucial role in distinct compartments of the female reproductive tract. This review accentuates the characteristics of tissue-resident immune cells in the vagina, endometrium, and the decidua during pregnancy and discusses their functional role in modulating the risk for infertility, pregnancy complications, infections, or cancer. We here also review data published to date on tissue-resident immunity in the male reproductive organs, which is still a largely uncharted territory.

The Role of Type I and Type II NKT Cells in Materno-Fetal Immunity

NKT cells represent a small but significant immune cell population as being a part of and bridging innate and adaptive immunity. Their ability to exert strong immune responses via cytotoxicity and cytokine secretion makes them significant immune effectors. Since pregnancy requires unconventional maternal immunity with a tolerogenic phenotype, investigation of the possible role of NKT cells in materno-fetal immune tolerance mechanisms is of particular importance. This review aims to summarize and organize the findings of previous studies in this field. Data and information about NKT cells from mice and humans will be presented, focusing on NKT cells characteristics during normal pregnancy in the periphery and at the materno-fetal interface and their possible involvement in female reproductive failure and pregnancy complications with an immunological background.

α-galactosylceramide-stimulated invariant natural killer T-cells play a protective role in murine vulvovaginal candidiasis by Candida albicans

BACKGROUND

Vulvovaginal candidiasis is a common superficial candidiasis; however, a host's immunological mechanism against vaginal Candida infection remains unknown.

OBJECTIVES

In this study, we aimed to elucidate the effect of iNKT cell activation on vulvovaginal candidiasis.

METHODS

Using a vulvovaginal candidiasis model with estrogenized mice, we evaluated the fungal burden and number of leukocyte infiltrations in the vaginal lavage of wild-type C57BL/6J mice after Candida albicans inoculation. One day before C. albicans inoculation, α-galactosylceramide (the α-GalCer group) or sterile phosphate-buffered saline (the sham group) was intraperitoneally injected into the mice. We also evaluated the level of antimicrobial peptide S100A8 in the vaginal lavage and analyzed the correlation between S100A8 concentration and the number of vaginal leukocyte infiltrations. Moreover, the number of uterine and vaginal immune cells were evaluated using flow cytometry.

RESULTS

The number of vaginal leukocyte infiltrations was significantly higher in the α-GalCer group than in the sham group 3 days after C. albicans inoculation. In addition, the fungal burden was significantly lower in the α-GalCer group than the sham group at 7 days after inoculation. In the analysis of S100A8 concentration of vaginal lavage, there were no significant differences between these two groups, although S100A8 concentration and the number of vaginal leukocyte infiltrations were positively correlated in the α-GalCer group. Moreover, the number of vaginal iNKT cells, NK cells and CD8+ T-cells was significantly higher in the α-GalCer group 3 days after inoculation.

CONCLUSIONS

α-GalCer-stimulated iNKT cells likely play a protective role against vulvovaginal candidiasis.

Changes in the Distribution of Intrauterine Microbiota May Attribute to Immune Imbalance in the CBA/J×DBA/2 Abortion-Prone Mice Model

Background: Female Genital Tract (FGT) is an important micro-ecological area of human body. Microbiota in the lower reproductive tract may subsequently invade the uterine cavity during embryo implantation and produce immune responses. CBA/J×DBA/2 mating combination has been widely used as an abortion-prone mice model but whether microbiota existed in their uterine cavity remains unclear. In this context, the role of the microbial communities in immune response deserves attention.

Objective: To investigate the relationship between the distribution of microbiota in the uterine cavity of CBA/J×DBA/2 abortion-prone mouse model and the immune imbalance of the maternal-fetal interface.

Methods: In this study, female CBA/J mice were paired with male DBA/2 mice to develop an abortion-prone model (BA group), and with male BALB/c mice to build a standard pregnancy model (BC group). The non-pregnant female mice were served as the control group (C group). Uterine flushing fluid and sera were collected on day 13.5 of pregnancy. 16S rRNA sequencing technology was used to analyze the distribution of intrauterine microbiota. Phylogenetic Investigation of Communities were conducted to predict the microbiota functions by Reconstruction of Unobserved States (PICRUST) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The serum IL 10, INF-γ, and TNF-α levels were examined using Enzyme-linked immunosorbent assay (ELISA) method.

Results: All samples were detected with microbial communities. The α diversity (p = 0.00077) had significant differences among three groups. Proteobacteria was the most dominant phylum in C group (mean = 83.21%) and BA group (mean = 43.23%). Firmicutes was dominant in BC group (mean = 46.4%), as well as the second dominant one in C group (mean = 12.63%) and BA group (mean = 40.55%). Microbiota functions were associated with metabolism and immune response through the NOD-like receptor signaling pathway. The serum IL 10 level in BA group were significantly lower than that in BC group (10.14 ± 1.90 pg/ml, n = 8; vs. 19.03 ± 1.82 pg/ml, n = 10; p = 0.004). The serum TNF-α and INF-γ level in BA group were also significantly higher than that in BC group (523.1 ± 58.14 pg/ml, n = 8 vs. 310.3 ± 28.51 pg/ml, n = 10, p = 0.0029; 69.22 ± 5.38 pg/ml, n = 8 vs. 50.85 ± 2.45 pg/ml, n = 10, p = 0.0042).

Conclusion: Microbial communities were colonized in uterine cavity of CBA/J mice both at non-pregnant stage and pregnant stage when mated with both BALB/c and DBA/2 male mice. The differentially abundant microbiome may be attributed to the immune tolerance through binding to the NOD-like receptor.

Relationship Between Pregnancy and Acute Disseminated Encephalomyelitis: A Single-Case Study

The relationship between pregnancy and autoimmune diseases is unclear. This study investigated the possible role of local immune changes and the activation state of the HMGB1/TLR4/Nf-κB/IL-6 pathway at the maternal–fetal interface during pregnancy in the pathogenesis of acute disseminated encephalomyelitis (ADEM). Clinical data and blood samples of a patient with ADEM were collected to observe the dynamic changes in lymphocyte populations after an abortion. The expression of HMGB1, TLR4, Nf-κB, AQP4, IL-2, IL-4, IL-6, and TNF-α in the fetal membrane and placenta was compared between the patient with pregnancy-related ADEM and a woman with a normal pregnancy using Real-time qPCR and western blotting (WB). The patient was diagnosed with ADEM in the early stage of pregnancy after showing limb weakness symptoms. In the third month of gestation, the symptoms worsened, with a disturbance of consciousness and breathing. After the abortion, the patient relapsed with vertigo and visual rotation. Analysis of lymphocyte subsets by flow cytometry showed that B lymphocytes increased, while natural killer T lymphocytes decreased. WB and Real-time qPCR showed that the expression levels of HMGB1, TLR4, Nf-κB, AQP4, and IL-6 in the fetal membrane and placenta were higher in the patient with pregnancy-related ADEM than in the woman with a normal pregnancy, while those of IL-2 were lower in the patient than in the woman with a normal pregnancy. The local immune changes and the activation of the HMGB1/TLR4/Nf-κB/IL-6 pathway at the maternal–fetal interface may be related to the pathogenesis of ADEM.

Inappropriate activation of invariant natural killer T cells and antigen-presenting cells with the elevation of HMGB1 in preterm births without acute chorioamnionitis

PROBLEM

Acute chorioamnionitis (aCAM) associated with microbial infection is a primary cause of preterm birth (PB). However, recent studies have demonstrated that innate immunity and sterile inflammation are causes of PB in the absence of aCAM. Therefore, we analyzed immune cells in the decidua of early to moderate PB without aCAM.

METHOD OF STUDY

Deciduas were obtained from patients with PB at a gestational age of 24⁺⁰ to 33⁺⁶  weeks without aCAM in pathological diagnosis. The patients were divided into two groups as follows: patients with labor and/or rupture of membrane (ROM) (no aCAM with labor and/or ROM: nCAM-w-LR), and patients without labor and/or ROM (no aCAM without labor and/or ROM: nCAM-w/o-LR). The immune cells and high mobility group box 1 (HMGB1) levels in the decidua were analyzed using flow cytometry. Co-culture of CD56⁺ cells with dendritic cells (DCs) and macrophages obtained from the decidua was also performed in the presence of HMGB1.

RESULTS

The nCAM-w-LR group demonstrated an accumulation of iNKT cells, and increased expression of HMGB1, TLR4, receptors for advanced glycation end products, and CD1d on DCs and macrophages. HMGB1 facilitated the proliferation of iNKT cells co-cultured with DCs and macrophages, which was found to be inhibited by heparin.

CONCLUSIONS

Inappropriate activation of innate immune cells and increased HMGB1 expression may represent parturition signs in human pregnancy. Therefore, control of these cells and HMGB1 antigenicity may be represent a potential therapeutic target for the prevention of PB.

Natural killer cells in cancer biology and therapy

The tumor microenvironment is highly complex, and immune escape is currently considered an important hallmark of cancer, largely contributing to tumor progression and metastasis. Named for their capability of killing target cells autonomously, natural killer (NK) cells serve as the main effector cells toward cancer in innate immunity and are highly heterogeneous in the microenvironment. Most current treatment options harnessing the tumor microenvironment focus on T cell-immunity, either by promoting activating signals or suppressing inhibitory ones. The limited success achieved by T cell immunotherapy highlights the importance of developing new-generation immunotherapeutics, for example utilizing previously ignored NK cells. Although tumors also evolve to resist NK cell-induced cytotoxicity, cytokine supplement, blockade of suppressive molecules and genetic engineering of NK cells may overcome such resistance with great promise in both solid and hematological malignancies. In this review, we summarized the fundamental characteristics and recent advances of NK cells within tumor immunometabolic microenvironment, and discussed potential application and limitations of emerging NK cell-based therapeutic strategies in the era of presicion medicine.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

Role of Natural Killer T (NKT) Cells in Type II Diabetes-Induced Vascular Injuries

Background

This study investigated the distribution and features of natural killer T (NKT) cells in the peripheral blood of diabetic patients, and their regulatory roles on vascular endothelial cells.

Material/Methods

Peripheral lymphocytes were isolated from diabetic patients. NKT cell distribution, proportion, and surface and intracellular markers were detected with flow cytometry. Peripheral blood-derived NKT cells were isolated and co-cultured with human umbilical vein endothelial cells (HUVECs). Proliferation and migration of HUVECs were assessed with the CCK-8 assay and the Transwell chamber assay.

Results

The ratios of CD3-CD56+ NK and CD3+CD56+ NKT cells in the peripheral blood of patients with type II diabetes were significantly elevated. The expression levels of NKp30, NKG2D, and NKp44 on the surface were increased in the CD3+CD56+ NKT cells, while the expression levels of NKG2A and 158b were significantly downregulated. The expression level of granzymes in the peripheral blood-derived NKT cells were not changed in patients with type II diabetes, but the expression levels of IFNγ and IL-4 were significantly increased. However, after co-culture with NKT cells derived from the peripheral blood of diabetic patients, the proliferation and migration of HUVECs were significantly inhibited, and was restored by treatment with IL-4 antibody. In addition, the IL-4 stimulus inhibited the proliferation and migration of HUVECs.

Conclusions

Peripheral blood NKT cells are increased and activated in diabetes. NKT cells inhibit the proliferation and migration of HUVECs by secreting IL-4, thereby inducing vascular injuries.

Tokishakuyakusan, a traditional Japanese medicine (Kampo) mitigates iNKT cell-mediated pregnancy loss in mice

OBJECTIVE

Tokishakuyakusan (TSS) is a traditional herbal medicine that has been used empirically to prevent recurrent pregnancy loss. Its mode of action remains unclear. With their potent capacity to produce cytokines, invariant natural killer (iNKT) cells are involved in the control of fetomaternal immunity in early gestation. This study aimed to clarify the effect of TSS on iNKT cell activities in a well-studied murine miscarriage model.

METHODS

Pregnant mice were fed 1% TSS-containing or control diet from the day of vaginal plug formation. Alpha-galactosylceramide (AGC) was administered intraperitoneally to the pregnant mice at day 9.5 postcoitus (pc) to stimulate iNKT cells. Peripheral cytokine levels were evaluated using cytokine arrays. The percentage of iNKT cells among splenocytes was examined by flow cytometric analysis. The incidence of pregnancy loss was assessed at day 12.5 pc.

RESULTS

The ratio of fetal resorptions to total conceptuses was significantly higher in the group exposed to TSS (34%) than in controls (78%). A rapid and robust surge in inflammatory cytokines, including IFN-γ and TNF-α, was detected in the peripheral blood of control animals 2 hours after AGC administration. This peripheral cytokine induction was significantly attenuated in the TSS-fed group compared with the control. The percentage of iNKT cells among total splenocytes was lower in the TSS-fed group than in controls.

CONCLUSION

The findings in this study suggest that the inhibitory effects of TSS on pregnancy loss may involve immune modulation of iNKT cells during early pregnancy.