The role of HMGB1 on TDI-induced NLPR3 inflammasome activation via ROS/NF-κB pathway in HBE cells

The role of HMGB1 on SiC NPs-induced inflammation response in lung epithelial-macrophage co-culture system

In recent years, carbonized silicon nanoparticles (SiC NPs) have found widespread scientific and engineering applications, raising concerns about potential human health risks. SiC NPs may induce pulmonary damage through sustained inflammatory responses and oxidative stress, with unclear toxicity mechanisms. This study uses an in vitro co-culture model of alveolar macrophages (NR8383) and alveolar epithelial cells (RLE-6TN) to simulate the interaction between airway epithelial cells and immune cells, providing initial insights into SiC NP-triggered inflammatory responses. The research reveals that increasing SiC NP exposure prompts NR8383 cells to release high mobility group box 1 protein (HMGB1), which migrates into RLE-6TN cells and activates the receptor for advanced glycation end-products (RAGE) and Toll-like receptor 4 (TLR4). RAGE and TLR4 synergistically activate the MyD88/NF-κB inflammatory pathway, ultimately inducing inflammatory responses and oxidative stress in RLE-6TN cells, characterized by excessive ROS generation and altered cytokine levels. Pretreatment with RAGE and TLR4 inhibitors attenuates SiC-induced HMGB1 expression and downstream pathway proteins, reducing inflammatory responses and oxidative damage. This highlights the pivotal role of RAGE-TLR4 crosstalk in SiC NP-induced pulmonary inflammation, providing insights into SiC NP cytotoxicity and nanomaterial safety guidelines.

Modulating synovial macrophage pyroptosis and mitophagy interactions to mitigate osteoarthritis progression using functionalized nanoparticles

Synovial macrophages play an important role in the progression of osteoarthritis (OA). In this study, we noted that synovial macrophages can activate pyroptosis in a gasdermin d-dependent manner and produce reactive oxygen species (ROS), aberrantly activating the mammalian target of rapamycin complex 1 (mTORC1) pathway and matrix metalloproteinase-9 (MMP9) expression in synovial tissue samples collected from both patients with OA and collagen-induced osteoarthritis (CIOA) mouse model. To overcome this, we constructed rapamycin- (RAPA, a mTORC1 inhibitor) loaded mesoporous Prussian blue nanoparticles (MPB NPs, for catalyzing ROS) and modified the NPs with MMP9-targeted peptides (favor macrophage targeting) to develop RAPA@MPB-MMP9 NPs. The inherent enzyme-like activity and RAPA released from RAPA@MPB-MMP9 NPs synergistically impeded the pyroptosis of macrophages and the activation of the mTORC1 pathway. In particular, the NPs decreased pyroptosis-mediated ROS generation, thereby inhibiting cGAS-STING signaling pathway activation caused by the release of mitochondrial DNA. Moreover, the NPs promoted macrophage mitophagy to restore mitochondrial stability, alleviate pyroptosis-related inflammatory responses, and decrease senescent synoviocytes. After the as-prepared NPs were intra-articularly injected into the CIOA mouse model, they efficiently attenuated synovial macrophage pyroptosis and cartilage degradation. In conclusion, our study findings provide a novel therapeutic strategy for OA that modulates the pyroptosis and mitophagy of synovial macrophage by utilizing functionalized NPs. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) presents a significant global challenge owing to its complex pathogenesis and finite treatment options. Synovial macrophages have emerged as key players in the progression of OA, managing inflammation and tissue destruction. In this study, we discovered a novel therapeutic strategy in which the pyroptosis and mitophagy of synovial macrophages are targeted to mitigate OA pathology. For this, we designed and prepared rapamycin-loaded mesoporous Prussian blue nanoparticles (RAPA@MPB-MMP9 NPs) to specifically target synovial macrophages and modulate their inflammatory responses. These NPs could efficiently suppress macrophage pyroptosis, diminish reactive oxygen species production, and promote mitophagy, thereby alleviating inflammation and protecting cartilage integrity. Our study findings not only clarify the intricate mechanisms underlying OA pathogenesis but also present a promising therapeutic approach for effectively managing OA by targeting dysregulation in synovial macrophages.

Unveiling the mechanisms of trichloroethylene hypersensitivity syndrome: Exploring the role of connexin 43 gap junctions in severe skin damage

Trichloroethylene (TCE), extensively used as an organic solvent in various industrial applications, has been identified as a causative factor in inducing hypersensitivity syndrome (THS). Currently, there is no specific treatment for THS, and most patients experience serious adverse outcomes due to extensive skin damage leading to severe infection. However, the pathogenesis of THS-associated skin damage remains unclear. This study aims to elucidate the mechanism underlying skin damage from the perspective of intercellular communication and gap junctions in THS. Our results verified that hyperactivation of connexin43 gap junctions, caused by the aberrantly elevated expression of connexin43, triggers a bystander effect that promotes apoptosis and inflammation in THS via the TNF-TNFRSF1B and mitochondria-associated pathways. Additionally, we identified the gap junction inhibitor Carbenoxolone disodium (CBX) as a promising agent for the treatment of skin damage in THS. CBX protects against inflammatory cell infiltration in the skin and decreases immune cell imbalance in the peripheral blood of THS mice. Furthermore, CBX reduces connexin43 expression, apoptosis and inflammation in THS mice. The study reveals new insights into the mechanisms underlying TCE-induced skin damage, offering a potential treatment strategy for the development of effective therapies targeting severe dermatitis induced by chemical exposure.

Granulysin-mediated reduction of PDZRN3 induces Cx43 gap junctions activity exacerbating skin damage in trichloroethylene hypersensitivity syndrome

Trichloroethylene (TCE)-induced hypersensitivity syndrome (THS) has been a concern for many researchers in the field of environmental and occupational health. Currently, there is no specific treatment for THS, leaving patients to contend with severe infections arising from extensive skin lesions, consequently leading to serious adverse effects. However, the pathogenesis of severe skin damage in THS remains unclear. This study aims to investigate the specific danger signals and mechanisms underlying skin damage in THS through in vivo and in vitro experiments. We identified that cell supernatant containing 15 kDa granulysin (GNLY), released from activated CD3-CD56+NK cells or CD3+CD56+NKT cells in PBMC induced by TCE or its metabolite, promoted apoptosis in HaCaT cells. The apoptosis level decreased upon neutralization of GNLY in the supernatant by a GNLY-neutralizing antibody in HaCaT cells. Subcutaneous injection of recombinant 15 kDa GNLY exacerbated skin damage in the THS mouse model and better mimicked patients' disease states. Recombinant 15 kDa GNLY could directly induce cellular communication disorders, inflammation, and apoptosis in HaCaT cells. In addition to its cytotoxic effects, GNLY released from TCE-activated NK cells and NKT cells or synthesized GNLY alone could induce aberrant expression of the E3 ubiquitin ligase PDZRN3, causing dysregulation of the ubiquitination of the cell itself. Consequently, this resulted in the persistent opening of gap junctions composed of connexin43, thereby intensifying cellular inflammation and apoptosis through the "bystander effect". This study provides experimental evidence elucidating the mechanisms of THS skin damage and offers a novel theoretical foundation for the development of effective therapies targeting severe dermatitis induced by chemicals or drugs.

HMGB1 inhibition reduces TDI-induced occupational asthma through ROS/AMPK/autophagy pathway

Exposure to toluene diisocyanate (TDI) can cause pulmonary diseases such as asthma. Inhibition of high mobility group box 1 protein (HMGB1) has been found to be protective against the toxic effects of TDI on human bronchial epithelial (HBE) cells. Here, we evaluated the in vivo positive roles of HMGB1 in the TDI-caused asthma mice and explored its underlying mechanisms in HBE cells. We found that suppression of HMGB1 obviously alleviated airway inflammation, airway hyperresponsiveness, and airway remodeling in the lung tissue of the asthma mice. The in vitro results showed that inhibition of HMGB1 ameliorated TDI-induced reactive oxygen species (ROS) release, inflammatory response, and activation of autophagy in HBE cells. At the molecular level, inhibition of HMGB1 decreased the expressions of HMGB1, Toll-like receptor 4, Vimentin and matrix metalloproteinase-9 proteins, activated NF-κB and NOD-like receptor protein 3 (NLRP3) inflammasome, and increased E-cadherin expression. Importantly, activation of autophagy could lead to the overactivation of NLRP3 inflammasome in TDI-induced asthma. These results suggest that inhibition of HMGB1 can alleviate TDI-induced asthma through ROS/AMPK/autophagy pathways, which may provide valuable evidence for the pathogenesis and therapeutic targets of TDI-induced asthma.

Repositioning itraconazole for amelioration of bleomycin-induced pulmonary fibrosis: Targeting HMGB1/TLR4 Axis, NLRP3 inflammasome/NF-κB signaling, and autophagy

BACKGROUND AND AIMS

Bleomycin (BLM) is one of the antitumor medications that had proven efficacy in the treatment of a wide range of malignant conditions. Pulmonary fibrosis which is frequently encountered during the course of bleomycin therapy may significantly reduce the potential efficacy of bleomycin in cancer therapy. This study tested the hypothesis that itraconazole may have mitigating effects on BLM-induced pulmonary fibrosis and tried to delineate the potential mechanisms of these effects.

MATERIALS AND METHODS

In a rat model of pulmonary fibrosis elicited by BLM, the effect of different doses of itraconazole was explored at the biochemical, histopathological, and electron microscopic levels.

KEY FINDINGS

Itraconazole, in a dose-dependent manner, exhibited significant effects on the pro-oxidant/antioxidant balance, the inflammatory consequences, high-mobility group box 1/toll-like receptor-4 Axis, autophagy and nuclear factor kappa B/Nod-like receptor protein 3 inflammasome signaling and alleviated the histopathological, immunohistochemical, and electron microscopic perturbations induced by BLM in the pulmonary tissues.

SIGNIFICANCE

In view of the afore-mentioned data, itraconazole may be a promising drug that efficiently mitigates the deleterious effects of BLM on the pulmonary tissues.

Hepatoprotective Effect of Mitochondria-Targeted Antioxidant Mito-TEMPO against Lipopolysaccharide-Induced Liver Injury in Mouse

The liver is vulnerable to sepsis, and sepsis-induced liver injury is closely associated with poor survival of sepsis patients. Studies have found that the overproduction of reactive oxygen species (ROS) is the major cause of oxidative stress, which is the main pathogenic factor for the progression of septic liver injury. The mitochondria are a major source of ROS. Mito-TEMPO is a mitochondria-specific superoxide scavenger. The aim of this study was to investigate the effect of Mito-TEMPO on lipopolysaccharide- (LPS-) induced sepsis mice. We found that Mito-TEMPO pretreatment inhibited inflammation, attenuated LPS-induced liver injury, and enhanced the antioxidative capability in septic mice, as evidenced by the decreased MDA content and the increased SOD activity. In addition, Mito-TEMPO restored mitochondrial size and improved mitochondrial function. Finally, we found that the levels of pyroptosis-related proteins in the liver of LPS-treated mice were lower after pretreatment with Mito-TEMPO. The mechanisms could be related to Mito-TEMPO enhanced antioxidative capability and improved mitochondrial function, which reflects the ability to neutralize ROS.

lncRNA HOTAIR Inhibition by Regulating HMGB1/ROS/NF-κB Signal Pathway Promotes the Recovery of Spinal Cord Function

Spinal cord ischemia-reperfusion injury (SCII) is one of the most serious complications of clinical aortic aneurysm and vascular malformation surgery. Long noncoding RNA (lncRNA) is involved in the progression of SCII, whereas long noncoding RNA HOX transcript antisense RNA (lncRNA HOTAIR) is unclear in SCII. This study is aimed at confirming the role and related mechanism of HOTAIR in SCII. Later on, a model of SCII was established by clamping the aortic arch for 14 minutes. RNA expression of HOTAIR was detected via qRT-PCR at 12 h, 24 h, 36 h, and 48 h after SCII. The Tarlov scoring system and TUNEL assay were used to evaluate neurological function and neuronal apoptosis. Oxidative stress factor levels were assessed according to the instructions of the kit. Inflammatory cytokines were assessed by ELISA. Western blot was used to detect levels of p65, p-p65, I-κBα, and p-I-κBα. We found HOTAIR was raised in SCII rats. si-HOTAIR was able to reverse SCII-induced oxidative stress in SCII rats. The HMGB1 expression was upregulated in SCII tissues and negatively correlated with HOTAIR. HMGB1 was able to partially reverse si-HOTAIR inhibition of oxidative stress, inflammatory injury, and neuronal cell apoptosis in SCII. In addition, the ROS/NF-κB signaling pathway is involved in HOTAIR/HMGB1 regulation of SCII. In a word, HOTAIR inhibition is able to inhibit oxidative stress, inflammatory injury, and neuronal apoptosis in SCII through downregulation of the high mobility group protein B1(HMGB1), which is achieved by inhibiting the ROS/NF-κB signaling pathway. The HOTAIR/HMGB1/ROS/NF-κB molecular pathway may be a new mechanism for the treatment of SCII.

Non-Coding RNAs: Master Regulators of Inflammasomes in Inflammatory Diseases

Emerging data indicates that non-coding RNAs (ncRNAs) represent more than just “junk sequences” of the genome and have been found to be involved in multiple diseases by regulating various biological process, including the activation of inflammasomes. As an important aspect of innate immunity, inflammasomes are large immune multiprotein complexes that tightly regulate the production of pro-inflammatory cytokines and mediate pyroptosis; the activation of the inflammasomes is a vital biological process in inflammatory diseases. Recent studies have emphasized the function of ncRNAs in the fine control of inflammasomes activation either by directly targeting components of the inflammasomes or by controlling the activity of various factors that control the activation of inflammasomes; consequently, ncRNAs may represent potential therapeutic targets for inflammatory diseases. Understanding the precise role of ncRNAs in controlling the activation of inflammasomes will help us to design targeted therapies for multiple inflammatory diseases. In this review, we summarize the regulatory role and therapeutic potential of ncRNAs in the activation of inflammasomes by focusing on a range of inflammatory diseases, including microbial infection, sterile inflammatory diseases, and fibrosis-related diseases. Our goal is to provide new ideas and perspectives for future research.