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Park S, Kim G, Choi A, Kim S, Yum JS, Chun E, Shin H. Comparative network-based analysis of toll-like receptor agonist, L-pampo signaling pathways in immune and cancer cells. Sci Rep 2024; 14:17173. [PMID: 39060412 PMCID: PMC11282102 DOI: 10.1038/s41598-024-67000-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Toll-like receptors (TLRs) are critical components to stimulate immune responses against various infections. Recently, TLR agonists have emerged as a promising way to activate anti-tumor immunity. L-pampo, a TLR1/2 and TLR3 agonist, induces humoral and cellular immune responses and also causes cancer cell death. In this study, we investigated the L-pampo-induced signals and delineated their interactions with molecular signaling pathways using RNA-seq in immune cells and colon and prostate cancer cells. We first constructed a template network with differentially expressed genes and influential genes from network propagation using the weighted gene co-expression network analysis. Next, we obtained perturbed modules using the above method and extracted core submodules from them by conducting Walktrap. Finally, we reconstructed the subnetworks of major molecular signals utilizing a shortest path-finding algorithm, TOPAS. Our analysis suggests that TLR signaling activated by L-pampo is transmitted to oxidative phosphorylation (OXPHOS) with reactive oxygen species (ROS) through PI3K-AKT and JAK-STAT only in immune and prostate cancer cells that highly express TLRs. This signal flow may further sensitize prostate cancer to L-pampo due to its high basal expression level of OXPHOS and ROS. Our computational approaches can be applied for inferring underlying molecular mechanisms from complex gene expression profiles.
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Affiliation(s)
- Sera Park
- MOGAM Institute for Biomedical Research, Seoul, 06730, Republic of Korea
| | - Geuntae Kim
- CHA Vaccine Institute, Seongnamsi, Gyenggido, 13488, South Korea
| | - Ahyoung Choi
- MOGAM Institute for Biomedical Research, Seoul, 06730, Republic of Korea
| | - Sun Kim
- MOGAM Institute for Biomedical Research, Seoul, 06730, Republic of Korea
- Interdisciplinary Program in Artificial Intelligence, Seoul National University, Seoul, 08826, Korea
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, 08826, Korea
| | - Jung Sun Yum
- CHA Vaccine Institute, Seongnamsi, Gyenggido, 13488, South Korea
| | - Eunyoung Chun
- CHA Vaccine Institute, Seongnamsi, Gyenggido, 13488, South Korea.
| | - Hyunjin Shin
- MOGAM Institute for Biomedical Research, Seoul, 06730, Republic of Korea.
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Malla R, Kumari S, Ganji SP, Srilatha M, Nellipudi HR, Nagaraju GP. Reactive oxygen species of tumor microenvironment: Harnessing for immunogenic cell death. Biochim Biophys Acta Rev Cancer 2024; 1879:189154. [PMID: 39019409 DOI: 10.1016/j.bbcan.2024.189154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 07/07/2024] [Accepted: 07/10/2024] [Indexed: 07/19/2024]
Abstract
The tumor microenvironment (TME) is a dynamic and complex system that undergoes continuous changes in its network architecture, notably affecting redox homeostasis. These alterations collectively shape a diverse ecosystem actively supporting tumor progression by influencing the cellular and molecular components of the TME. Despite the remarkable clinical advancements in cancer immunotherapy, its spectrum of clinical utility is limited by the altered TME and inadequate tumor immunogenicity. Recent studies have revealed that some conventional and targeted therapy strategies can augment the efficacy of immunotherapy even in patients with less immunogenic solid tumors. These strategies provoke immunogenic cell death (ICD) through the ROS-dependent liberation of damage-associated molecular patterns (DAMPs). These DAMPs recognize and bind with Pattern Recognition Receptors (PRRs) on immune cells, activating and maturing defense cells, ultimately leading to a robust antitumor immune response. The present review underscores the pivotal role of redox homeostasis in orchestrating the transition of TME from a cold to a hot phenotype and the ROS-ICD axis in immune response induction. Additionally, it provides up-to-date insights into strategies that leverage ROS generation to induce ICD. The comprehensive analysis aims to develop ROS-based effective cancer immunotherapies for less immunogenic tumors.
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Affiliation(s)
- RamaRao Malla
- Cancer Biology Laboratory, Department of Biochemistry and Bioinformatics, School of Science, GITAM (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India
| | - Seema Kumari
- Cancer Biology Laboratory, Department of Biochemistry and Bioinformatics, School of Science, GITAM (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India
| | - Swapna Priya Ganji
- Cancer Biology Laboratory, Department of Biochemistry and Bioinformatics, School of Science, GITAM (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India
| | - Mundla Srilatha
- Department of Biotechnology, Sri Venkateswara University, Tirupati, Andhra Pradesh 517502, India
| | | | - Ganji Purnachandra Nagaraju
- Department of Hematology and Oncology, Heersink School of Medicine, University of Alabama, Birmingham, AL 35233, USA.
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Mukherjee S, Patra R, Behzadi P, Masotti A, Paolini A, Sarshar M. Toll-like receptor-guided therapeutic intervention of human cancers: molecular and immunological perspectives. Front Immunol 2023; 14:1244345. [PMID: 37822929 PMCID: PMC10562563 DOI: 10.3389/fimmu.2023.1244345] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/07/2023] [Indexed: 10/13/2023] Open
Abstract
Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.
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Affiliation(s)
- Suprabhat Mukherjee
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India
| | - Ritwik Patra
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India
| | - Payam Behzadi
- Department of Microbiology, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
| | - Andrea Masotti
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
| | - Alessandro Paolini
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
| | - Meysam Sarshar
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
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Zhu X, Li S. Ferroptosis, Necroptosis, and Pyroptosis in Gastrointestinal Cancers: The Chief Culprits of Tumor Progression and Drug Resistance. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300824. [PMID: 37436087 PMCID: PMC10502844 DOI: 10.1002/advs.202300824] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/29/2023] [Indexed: 07/13/2023]
Abstract
In recent years, the incidence of gastrointestinal cancers is increasing, particularly in the younger population. Effective treatment is crucial for improving patients' survival outcomes. Programmed cell death, regulated by various genes, plays a fundamental role in the growth and development of organisms. It is also critical for maintaining tissue and organ homeostasis and takes part in multiple pathological processes. In addition to apoptosis, there are other types of programmed cell death, such as ferroptosis, necroptosis, and pyroptosis, which can induce severe inflammatory responses. Notably, besides apoptosis, ferroptosis, necroptosis, and pyroptosis also contribute to the occurrence and development of gastrointestinal cancers. This review aims to provide a comprehensive summary on the biological roles and molecular mechanisms of ferroptosis, necroptosis, and pyroptosis, as well as their regulators in gastrointestinal cancers and hope to open up new paths for tumor targeted therapy in the near future.
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Affiliation(s)
- Xudong Zhu
- Department of General SurgeryCancer Hospital of Dalian University of TechnologyCancer Hospital of China Medical UniversityLiaoning Cancer Hospital and InstituteShenyangLiaoning Province110042China
| | - Shenglong Li
- Second Ward of Bone and Soft Tissue Tumor SurgeryCancer Hospital of Dalian University of TechnologyCancer Hospital of China Medical UniversityLiaoning Cancer Hospital and InstituteShenyangLiaoning Province110042China
- The Liaoning Provincial Key Laboratory of Interdisciplinary Research on Gastrointestinal Tumor Combining Medicine with EngineeringShenyangLiaoning Province110042China
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Zhang W, Xu L, Zhang X, Xu J, Jin JO. Escherichia coli adhesion portion FimH polarizes M2 macrophages to M1 macrophages in tumor microenvironment via toll-like receptor 4. Front Immunol 2023; 14:1213467. [PMID: 37720226 PMCID: PMC10502728 DOI: 10.3389/fimmu.2023.1213467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/15/2023] [Indexed: 09/19/2023] Open
Abstract
Background Macrophages are key effector cells of innate immunity and play a critical role in the immune balance of disease pathogenesis, especially in the tumor microenvironment. In previous studies, we showed that FimH, an Escherichia coli adhesion portion, promoted dendritic cell activation. However, the effect of FimH in macrophage polarization has yet to be fully examined. In this study, we investigated the potential effect of FimH on macrophages, as well as the polarization from M2 to M1 macrophages, contributing to the overall antitumor effect. Methods Mouse bone marrow derived macrophages and peritoneal macrophages were generated to test the effect of FimH in vitro. The expression of costimulatory molecules and production of cytokines were analyzed. The effect of FimH in the tumor-associated macrophages was examine in the B16F10-tumor bearing C57BL/6. Results FimH was found to promote M1 macrophage activation. In addition, FimH polarized M2 macrophages, which were induced by interleukin (IL)-4 and IL-13 into M1 macrophages were dependent on toll-like receptor 4 and myeloid differentiation factor 2. Moreover, FimH reprogramed the tumor-associated macrophage (TAM) into M1 macrophages in B16 melanoma tumor-bearing mice and promoted an inflammatory reaction in the tumor microenvironment (TME). Furthermore, FimH promoted M1 macrophage activation, as well as the reversion of M2 macrophages into M1 macrophages in humans. Finally, FimH treatment was found to enhance the anti-cancer immunity of anti-PD-L1 antibody by the induction of M1 polarization from TAM. Conclusion This study demonstrated the potential effect of FimH on the activation of macrophages, responsible for the repolarization of M2 macrophages into the M1 phenotype via the TLR4 signaling pathway. Moreover, FimH could also reprogram TAM polarization to the M1 status in the TME, as well as enhance the anti-tumor activity of immune checkpoint blockade.
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Affiliation(s)
- Wei Zhang
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, Shanghai, China
| | - Li Xu
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiaoyan Zhang
- The Laboratory for Immunotherapy, Clinical Center for BioTherapy, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianqing Xu
- The Laboratory for Immunotherapy, Clinical Center for BioTherapy, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jun-O Jin
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, Shanghai, China
- Dpartment of Microbiology, University of Ulsan College of Medicine, ASAN Medical Center, Seoul, Republic of Korea
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Budhiraja S, Najem H, Tripathi S, Wadhawani NR, Horbinski C, McCord M, Lenzen AC, Heimberger AB, DeCuypere M. Immunobiology and Cytokine Modulation of the Pediatric Brain Tumor Microenvironment: A Scoping Review. Cancers (Basel) 2023; 15:3655. [PMID: 37509316 PMCID: PMC10377457 DOI: 10.3390/cancers15143655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/06/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Utilizing a Scoping Review strategy in the domain of immune biology to identify immune therapeutic targets, knowledge gaps for implementing immune therapeutic strategies for pediatric brain tumors was assessed. The analysis demonstrated limited efforts to date to characterize and understand the immunological aspects of tumor biology with an over-reliance on observations from the adult glioma population. Foundational knowledge regarding the frequency and ubiquity of immune therapeutic targets is an area of unmet need along with the development of immune-competent pediatric tumor models to test therapeutics and especially combinatorial treatment. Opportunities arise in the evolution of pediatric tumor classification from histological to molecular with targeted immune therapeutics.
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Affiliation(s)
- Shreya Budhiraja
- Division of Pediatric Neurosurgery, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hinda Najem
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Shashwat Tripathi
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nitin R Wadhawani
- Division of Pathology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Craig Horbinski
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Matthew McCord
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Alicia C Lenzen
- Division of Hematology, Oncology, Neuro-Oncology, and Stem Cell Transplantation, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Amy B Heimberger
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Michael DeCuypere
- Division of Pediatric Neurosurgery, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Hibino S, Eto S, Hangai S, Endo K, Ashitani S, Sugaya M, Osawa T, Soga T, Taniguchi T, Yanai H. Tumor cell-derived spermidine is an oncometabolite that suppresses TCR clustering for intratumoral CD8 + T cell activation. Proc Natl Acad Sci U S A 2023; 120:e2305245120. [PMID: 37276392 PMCID: PMC10268234 DOI: 10.1073/pnas.2305245120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/03/2023] [Indexed: 06/07/2023] Open
Abstract
The activation and expansion of T cells that recognize cancer cells is an essential aspect to antitumor immunity. Tumors may escape destruction by the immune system through ectopic expression of inhibitory immune ligands typically exemplified by the PD-L1/PD-1 pathway. Here, we reveal another facet of tumor evasion from T cell surveillance. By secretome profiling of necrotic tumor cells, we identified an oncometabolite spermidine as a unique inhibitor of T cell receptor (TCR) signaling. Mechanistically, spermidine causes the downregulation of the plasma membrane cholesterol levels, resulting in the suppression of TCR clustering. Using syngeneic mouse models, we show that spermidine is abundantly detected in the tumor immune microenvironment (TIME) and that administration of the polyamine synthesis inhibitor effectively enhanced CD8+ T cell-dependent antitumor responses. Further, the combination of the polyamine synthesis inhibitor with anti-PD-1 immune checkpoint antibody resulted in a much stronger antitumor immune response. This study reveals an aspect of immunosuppressive TIME, wherein spermidine functions as a metabolic T cell checkpoint that may offer a unique approach for promoting tumor immunotherapy.
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Affiliation(s)
- Sana Hibino
- Department of Inflammology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-0041, Japan
| | - Shotaro Eto
- Department of Inflammology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-0041, Japan
| | - Sho Hangai
- Department of Inflammology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-0041, Japan
| | - Keiko Endo
- Institute for Advanced Biosciences, Keio University, Yamagata997-0052, Japan
| | - Sanae Ashitani
- Institute for Advanced Biosciences, Keio University, Yamagata997-0052, Japan
| | - Maki Sugaya
- Division of Nutriomics and Oncology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-8904, Japan
| | - Tsuyoshi Osawa
- Division of Nutriomics and Oncology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-8904, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Yamagata997-0052, Japan
| | - Tadatsugu Taniguchi
- Department of Inflammology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-0041, Japan
| | - Hideyuki Yanai
- Department of Inflammology, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo153-0041, Japan
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Badve SS, Gökmen-Polar Y. Targeting the Tumor-Tumor Microenvironment Crosstalk. Expert Opin Ther Targets 2023; 27:447-457. [PMID: 37395003 DOI: 10.1080/14728222.2023.2230362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 06/23/2023] [Indexed: 07/04/2023]
Abstract
INTRODUCTION Cancer development and progression is a complex process influenced by co-evolution of the cancer cells and their microenvironment. However, traditional anti-cancer therapy is mostly targeted toward cancer cells. To improve the efficacy of cancer drugs, the complex interactions between the tumor (T) and the tumor microenvironment (TME) should be considered while developing therapeutics. AREAS COVERED The present review article will discuss the components of T-TME as well as the potential to co-target these two distinct elements. We document that these approaches have resulted in success in preventing tumor progression and metastasis, albeit in animal models in some cases. Lastly, it is important to consider the tissue context and tumor type as these could significantly modify the role of these molecules/pathways and hence the overall likelihood of response. Furthermore, we discuss the potential strategies to target the components of tumor microenvironment in anti-cancer therapy. PubMed and ClinicalTrials.gov was searched through May 2023. EXPERT OPINION The tumor-tumor microenvironment cross talk and heterogeneity are major mechanisms conferring resistance to standard of care. Better understanding of the tissue specific T-TME interactions and dual targeting has the promise of improving cancer control and clinical outcomes.
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Affiliation(s)
- Sunil S Badve
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - Yesim Gökmen-Polar
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
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Tsuboi H, Segawa S, Yagishita M, Toko H, Honda F, Kitada A, Miki H, Ohyama A, Hagiwara S, Kondo Y, Matsumoto I, Sumida T. Activation mechanisms of monocytes/macrophages in adult-onset Still disease. Front Immunol 2022; 13:953730. [PMID: 36090971 PMCID: PMC9461677 DOI: 10.3389/fimmu.2022.953730] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/02/2022] [Indexed: 12/23/2022] Open
Abstract
Adult onset Still disease (AOSD) is a systemic inflammatory disorder characterized by skin rash, spiking fever, arthritis, sore throat, lymphadenopathy, and hepatosplenomegaly. Although the etiology of this disease has not been fully clarified, both innate and acquired immune responses could contribute to its pathogenesis. Hyperactivation of macrophages and neutrophils along with low activation of natural killer (NK) cells in innate immunity, as well as hyperactivation of Th1 and Th17 cells, whereas low activation of regulatory T cells (Tregs) in acquired immunity are involved in the pathogenic process of AOSD. In innate immunity, activation of monocytes/macrophages might play central roles in the development of AOSD and macrophage activation syndrome (MAS), a severe life-threating complication of AOSD. Regarding the activation mechanisms of monocytes/macrophages in AOSD, in addition to type II interferon (IFN) stimulation, several pathways have recently been identified, such as the pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs)-pattern recognition receptors (PRRs) axis, and neutrophil extracellular traps (NETs)-DNA. These stimulations on monocytes/macrophages cause activation of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain (NLRP) 3 inflammasomes, which trigger capase-1 activation, resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms. Thereafter, IL-1β and IL-18 produced by activated monocytes/macrophages contribute to various clinical features in AOSD. We identified placenta-specific 8 (PLAC8) as a specifically increased molecule in monocytes of active AOSD, which correlated with serum levels of CRP, ferritin, IL-1β, and IL-18. Interestingly, PLAC8 could suppress the synthesis of pro-IL-1β and pro-IL-18 via enhanced autophagy; thus, PLAC8 seems to be a regulatory molecule in AOSD. These findings for the activation mechanisms of monocytes/macrophages could shed light on the pathogenesis and development of a novel therapeutic strategy for AOSD.
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