Browsing by Subject "CD1d"

Now showing 1 - 6 of 6
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    Alterations in cellular metabolism modulate CD1d-mediated NKT-cell responses
    (Oxford, 2016-08) Webb, Tonya J.; Carey, Gregory B.; East, James E.; Sun, Wenji; Bollino, Dominique R.; Kimball, Amy S.; Brutkiewicz, Randy R.; Microbiology and Immunology, School of Medicine
    Natural killer T (NKT) cells play a critical role in the host's innate immune response. CD1d-mediated presentation of glycolipid antigens to NKT cells has been established; however, the mechanisms by which NKT cells recognize infected or cancerous cells remain unclear. 5′-AMP activated protein kinase (AMPK) is a master regulator of lipogenic pathways. We hypothesized that activation of AMPK during infection and malignancy could alter the repertoire of antigens presented by CD1d and serve as a danger signal to NKT cells. In this study, we examined the effect of alterations in metabolism on CD1d-mediated antigen presentation to NKT cells and found that an infection with lymphocytic choriomeningitis virus rapidly increased CD1d-mediated antigen presentation. Hypoxia inducible factors (HIF) enhance T-cell effector functions during infection, therefore antigen presenting cells pretreated with pharmacological agents that inhibit glycolysis, induce HIF and activate AMPK were assessed for their ability to induce NKT-cell responses. Pretreatment with 2-deoxyglucose, cobalt chloride, AICAR and metformin significantly enhanced CD1d-mediated NKT-cell activation. In addition, NKT cells preferentially respond to malignant B cells and B-cell lymphomas express HIF-1α. These data suggest that targeting cellular metabolism may serve as a novel means of inducing innate immune responses.
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    Blocking the innate immune CD1d/NKT cell axis prevents the development of cortical hyperexcitability and posttraumatic epilepsy
    (Wiley, 2025) Ping, Xingjie; Xiong, Wenhui; Priya, Raj; Liu, Jianyun; Wyatt-Johnson, Season K.; Brutkiewicz, Randy R.; Jin, Xiaoming; Anatomy, Cell Biology and Physiology, School of Medicine
    Objective: Posttraumatic epilepsy (PTE) that develops after a traumatic brain injury (TBI) cannot be prevented by current treatments. Although neuroinflammation is involved in epileptogenesis, a potential role for cellular immunity in this process is largely unknown. Natural killer T (NKT) cells are innate-like T lymphocytes that recognize lipid antigens presented by the major histocompatibility complex class I-like CD1d molecule and play a crucial role in regulating immune responses. Herein we examined the role of the CD1d/NKT cell axis in PTE. Methods: We used an undercut surgery to induce TBI in wild-type (WT) and CD1d-deficient (CD1d knockout [KO], CD1d KO) or NKT cell-deficient (Traj18 KO) mice. A pentylenetetrazol (PTZ) test was used to determine seizure susceptibility in vivo, and field potential recordings were made from cortical slices in vitro. Continuous video and wireless EEG monitoring was undertaken of WT and CD1d KO mice between 5 and 8 weeks after brain injury. Because statins are known to impair antigen presentation by CD1d to NKT cells, we also treated WT mice with simvastatin for 10 days after injury and performed the PTZ test. Immunofluorescence and flow cytometry were used to determine changes in immune cells in brain tissue. Results: CD1d KO or Traj18 KO TBI mice had a significantly lower seizure susceptibility than WT mice on the PTZ test. CD1d KO mice had a significantly lower rate of detectable epileptiform activities during field potential recording. Video and EEG monitoring showed that CD1d KO TBI mice had a significantly lower frequency of spontaneous epileptic seizures. There was increased infiltration of immune cells, but reduced microgliosis in the brains of these mice. Simvastatin treatment significantly reduced seizure susceptibility in TBI mice. Significance: Neuroinflammation initiated by the CD1d/NKT cell axis is involved in the development of cortical hyperexcitability and PTE; early treatment with simvastatin following a TBI exerts a prophylactic effect on posttraumatic epileptogenesis by blocking this axis.
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    JNK2 modulates the CD1d-dependent and -independent activation of iNKT cells
    (Wiley, 2019-02) Liu, Jianyun; Gallo, Richard M.; Khan, Masood A.; Iyer, Abhirami K.; Kratzke, Ian M.; Brutkiewicz, Randy R.; Microbiology and Immunology, School of Medicine
    Invariant Natural Killer T (iNKT) cells play critical roles in autoimmune, anti-tumor and anti-microbial immune responses, and are activated by glycolipids presented by the MHC class I-like molecule, CD1d. How the activation of signaling pathways impacts antigen (Ag)-dependent iNKT cell activation is not well-known. In the current study, we found that the MAPK JNK2 not only negatively regulates CD1d-mediated Ag presentation in APCs, but also contributes to CD1d-independent iNKT cell activation. A deficiency in the JNK2 (but not JNK1) isoform enhanced Ag presentation by CD1d. Using a vaccinia virus (VV) infection model known to cause a loss in iNKT cells in a CD1d-independent, but IL-12-dependent manner, we found the virus-induced loss of iNKT cells in JNK2 KO mice was substantially lower than that observed in JNK1 KO or wildtype (WT) mice. Importantly, compared to WT mice, JNK2 KO mouse iNKT cells were found to express less surface IL-12 receptors. As with a VV infection, an IL-12 injection also resulted in a smaller decrease in JNK2 KO iNKT cells as compared to WT mice. Overall, our work strongly suggests JNK2 is a negative regulator of CD1d-mediated Ag presentation and contributes to IL-12-induced iNKT cell activation and loss during viral infections.
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    Neurofibromin 1 Impairs Natural Killer T-Cell-Dependent Antitumor Immunity against a T-Cell Lymphoma
    (Frontiers Media, 2018-01-05) Liu, Jianyun; Gallo, Richard M.; Khan, Masood A.; Renukaradhya, Gourapura J.; Brutkiewicz, Randy R.; Microbiology and Immunology, School of Medicine
    Neurofibromin 1 (NF1) is a tumor suppressor gene encoding a Ras GTPase that negatively regulates Ras signaling pathways. Mutations in NF1 are linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. In terms of antitumor immunity, CD1d-dependent natural killer T (NKT) cells play an important role in the innate antitumor immune response. Generally, Type-I NKT cells protect (and Type-II NKT cells impair) host antitumor immunity. We have previously shown that CD1d-mediated antigen presentation to NKT cells is regulated by cell signaling pathways. To study whether a haploinsufficiency in NF1 would affect CD1d-dependent activation of NKT cells, we analyzed the NKT-cell population as well as the functional expression of CD1d in Nf1+/- mice. Nf1+/- mice were found to have similar levels of NKT cells as wildtype (WT) littermates. Interestingly, however, reduced CD1d expression was observed in Nf1+/- mice compared with their WT littermates. When inoculated with a T-cell lymphoma in vivo, Nf1+/- mice survived longer than their WT littermates. Furthermore, blocking CD1d in vivo significantly enhanced antitumor activity in WT, but not in Nf1+/- mice. In contrast, a deficiency in Type-I NKT cells increased antitumor activity in Nf1+/- mice, but not in WT littermates. Therefore, these data suggest that normal NF1 expression impairs CD1d-mediated NKT-cell activation and antitumor activity against a T-cell lymphoma.
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    A Potent CD1d-binding Glycolipid for iNKT-Cell-based Therapy Against Human Breast Cancer
    (International Institute of Anticancer Research, 2019-02-01) Seki, Toshiyuki; Liu, Jianyun; Brutkiewicz, Randy R.; Tsuji, Moriya; Microbiology and Immunology, School of Medicine
    Background/Aim: Invariant natural killer T-cells (iNKT) stimulated by CD1d-binding glycolipids have been shown to exert antitumor effects by a number of studies in a mouse model. Breast cancer is a devastating disease, with different types of breast cancer recurring locally or distant as metastatic/advanced disease following initial treatment. The aim of this study was to examine the tumoricidal effect of a CD1d-binding glycolipid, called 7DW8-5, against a highly invasive human breast cancer cell line both in vitro and in vivo. Materials and Methods: Parental MDA-MB-231 cells and MDA-MB-231 cells transduced with human CD1d were labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE), followed by loading with glycolipids. After co-culturing with human iNKT cells, the cells were permeabilized and stained with Alexa Flour 647-conjugated antibody to active caspase-3, and analyzed using a BD LSR II. For the in vivo tumoricidal effect, MDA-MB-231 cells transduced with human CD1d and luciferase genes were injected into the mammary fat pad of female NOD/SCID/IL2rγnull (NSG) mice, followed by the injection of human iNKT cells with or without 7DW8-5, and the levels of luminescence were analyzed with whole-body imaging. Results: Human iNKT cells could kill CD1d-expressing human breast cancer cells in vitro in the presence of 7DW8-5, but not α-GalCer. As for in vivo, the adoptive transfer of human iNKT cells into tumor-challenged NSG mice significantly inhibited the growth of CD1d+ MDA-MB-231 human breast cancer cells in the presence of 7DW8-5. Conclusion: CD1d-binding, glycolipid-based iNKT-cell therapy is suggested as a potent and effective treatment against breast cancer in humans.
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    The Immune System in Neurological Diseases: What Innate-like T Cells have to Say
    (Elsevier, 2024) Wyatt-Johnson, Season K.; Afify, Reham; Brutkiewicz, Randy R.; Microbiology and Immunology, School of Medicine
    The immune system classically consists of 2 lines of defense, innate and adaptive, both of which interact with one another effectively to protect us against any pathogenic threats. Importantly, there is a diverse subset of cells known as innate-like T cells that act as a bridge between the innate and adaptive immune systems and are pivotal players in eliciting inflammatory immune responses. A growing body of evidence has demonstrated the regulatory impact of these innate-like T cells in central nervous system (CNS) diseases and that such immune cells can traffic into the brain in multiple pathological conditions, which can be typically attributed to the breakdown of the blood-brain barrier. However, until now, it has been poorly understood whether innate-like T cells have direct protective or causative properties, particularly in CNS diseases. Therefore, in this review, our attention is focused on discussing the critical roles of 3 unique subsets of unconventional T cells, namely, natural killer T cells, γδ T cells, and mucosal-associated invariant T cells, in the context of CNS diseases, disorders, and injuries and how the interplay of these immune cells modulates CNS pathology, in an attempt to gain a better understanding of their complex functions.