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Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria. [ABSTRACT FROM AUTHOR]

Background/purpose: Periodontitis is one of the highly prevalent chronic inflammatory conditions in adults. The importance of circular RNAs (circRNAs) in the regulation of inflammation has been gradually reported in recent years, but the role of circRNA circ_0099630 in periodontitis has not been reported., Materials and Methods: The contents of circ_0099630, microRNA-940 (miR-940) and tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot. Inflammatory factor secretion, cell proliferation, and apoptosis were analyzed under the application of Enzyme-linked immunosorbent assay (ELISA), Cell Counting Kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry, respectively. The Western blot also analyzed the phosphorylation levels of RELA proto-oncogene (P65) and IkappaBalpha (IκBα), key molecules of the nuclear factor kappa-B (NF-κB) pathway. The relationship between miR-940 and circ_0099630 or TRAF6 was verified by luciferase reporter system and RNA immunoprecipitation (RIP) assay., Results: Higher abundance of circ_0099630 and TRAF6 and lower miR-940 expression were observed in periodontitis, and circ_0099630 knockdown attenuated the damage of human PDL cells (PDLCs) induced by lipopolysaccharides (LPS). The relationship between miR-940 and circ_0099630 or TRAF6 was evidenced, while miR-940 downregulation diminished the repair effect of si-circ_0099630 on overexpression LPS-induced damage in PDLCs. Similarly, TRAF6 upregulation impaired the mitigating effect of miR-940 overexpression on LPS-induced injury in PDLCs. Circ_0099630 silencing evidently curbed the phosphorylation levels of P65 and IκBα and thus attenuating the inflammatory response by acting on the miR-940/TRAF6 axis., Conclusion: Silencing circ_0099630 alleviates LPS-induced periodontal ligament cell injury via targeting miR-940/TRAF6/NF-κB in periodontitis., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2022 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

NF-κB activator 1 (Act1), also called CIKS, is a recently identified protein with NF-κB and AP-1 activation activities through its association with the IκB kinase complex. We identified and confirmed that Act1 interacts with tumor necrosis factor receptor-associated factor 6 (TRAF6); notably, Act1 binds to TRAF6 only among TRAF family proteins. The amino-terminal half of Act1 is required for its interaction with the TRAF domain. Act1-mediated NF-κB activation was inhibited by a dominant-negative mutant of TRAF6 in a dose-dependent manner, and IL-1-induced NF-κB activation was inhibited by a high level of Act1 expression. Our results suggest that Act1 is involved in IL-1/Toll-mediated signaling through TRAF6. [Copyright &y& Elsevier]

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling exert essential regulatory function in microbial-and onco-immunology through the induction of cytokines, primarily type I interferons. Recently, the aberrant and deranged signaling of the cGAS-STING axis is closely implicated in multiple sterile inflammatory diseases, including heart failure, myocardial infarction, cardiac hypertrophy, nonalcoholic fatty liver diseases, aortic aneurysm and dissection, obesity, etc. This is because of the massive loads of damage-associated molecular patterns (mitochondrial DNA, DNA in extracellular vesicles) liberated from recurrent injury to metabolic cellular organelles and tissues, which are sensed by the pathway. Also, the cGAS-STING pathway crosstalk with essential intracellular homeostasis processes like apoptosis, autophagy, and regulate cellular metabolism. Targeting derailed STING signaling has become necessary for chronic inflammatory diseases. Meanwhile, excessive type I interferons signaling impact on cardiovascular and metabolic health remain entirely elusive. In this review, we summarize the intimate connection between the cGAS-STING pathway and cardiovascular and metabolic disorders. We also discuss some potential small molecule inhibitors for the pathway. This review provides insight to stimulate interest in and support future research into understanding this signaling axis in cardiovascular and metabolic tissues and diseases., Competing Interests: The authors have no conflicts of interest to declare., (© 2022 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.)

The initiation and development of major inflammatory diseases, i.e. , cancer, vascular inflammation, and some autoimmune diseases are closely linked to the immune system. Biologics-based immunotherapy is exerting a critical role against these diseases, whereas the usage of the immunomodulators is always limited by various factors such as susceptibility to digestion by enzymes in vivo , poor penetration across biological barriers, and rapid clearance by the reticuloendothelial system. Drug delivery strategies are potent to promote their delivery. Herein, we reviewed the potential targets for immunotherapy against the major inflammatory diseases, discussed the biologics and drug delivery systems involved in the immunotherapy, particularly highlighted the approved therapy tactics, and finally offer perspectives in this field., Competing Interests: The authors have no conflicts of interest to declare., (© 2021 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.)

Background: Parkinson's disease (PD) is a neurodegenerative disease characterized by intracellular inclusions named Lewy bodies (LB), and alpha-synuclein (asyn) is the major component of these protein aggregates. The precise physiological and pathological roles of asyn are not fully understood. Nevertheless, asyn present in LB is ubiquitinated but fails to reach the 26S proteasome. The mutation A30 P is related to an aggressive and early-onset form of PD. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase, and it interacts and ubiquitinates the asyn in atypical chains (lysine K6, K27, K29, and K33). Methods: Here, we investigated the role of TRAF6 interaction with asyn and the involvement of nuclear factor κB (NF-κB), a key transcription factor in pro-inflammatory signaling pathway activation., Results and Conclusion: We demonstrated that TRAF6 binds to both WT and the mutant form A30 P asyn in an SH-SY5Y cell model. Additionally, the interaction between TRAF6 and WT asyn induced an increase in the activation of NF-κB, leading to changes in TNF, IL-1β and IL-10 levels and culminating in reduced cell viability. Interestingly, the activation of NF-κB and gene regulation were not found in A30 P asyn. These data point to a novel role of TRAF6 in the pathophysiology of PD., (© 2020 The Authors.)

Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria., (Copyright © 2018. Published by Elsevier Inc.)