NLRP3: Role in ischemia/reperfusion injuries

Bifidobacterium longum Metabolite Indole-3-Carboxaldehyde Blocks HDAC3 and Inhibits Macrophage NLRP3 Inflammasome Activation in Intestinal Ischemia/Reperfusion Injury

Indole-3-carboxaldehyde (3-IAld), a tryptophan metabolite derived from gut microbiota, has been reported to protect the intestine against radiation injury. This study aimed to clarify the role of Bifidobacterium longum (B. longum) and its metabolite indole-3-carboxaldehyde (3-IAld) in the pathophysiology of intestinal ischemia/reperfusion (II/R) injury. Superior mesenteric artery occlusion and reperfusion were performed to establish II/R mice, and pathological injury in II/R mice was evaluated. II/R mice showed impaired gut microbiota diversity and reduced abundance of B. longum in the intestines. Transplantation of B. longum mitigated II/R injury by protecting the integrity of the intestinal barrier and reducing inflammatory response. The 3-IAld level increased after transplantation of B. longum, and 3-IAld treatment inhibited the inflammatory response of bone marrow-derived macrophages (BMDM). Histone deacetylase 3 (HDAC3) was a target of 3-IAld, and HDAC3 was translocated to mitochondria to promote mitochondrial fatty acid oxidation (FAO) during macrophage inflammasome formation. HDAC3 overexpression promoted the formation of macrophage inflammasomes in intestinal tissues. Overall, this study confirmed the beneficial effects of B. longum in combating II/R injury through HDAC3-mediated control of mitochondrial FAO and macrophage inflammasome formation via 3-IAld.

Aquaporin proteins: A promising frontier for therapeutic intervention in cerebral ischemic injury

Cerebral ischemic injury is characterized by reduced blood flow to the brain, remains a significant cause of morbidity and mortality worldwide. Despite improvements in therapeutic approaches, there is an urgent need to identify new targets to lessen the effects of ischemic stroke. Aquaporins, a family of water channel proteins, have recently come to light as promising candidates for therapeutic intervention in cerebral ischemic injury. There are 13 aquaporins identified, and AQP4 has been thoroughly involved with cerebral ischemia as it has been reported that modulation of AQP4 activity can offers a possible pathway for therapeutic intervention along with their role in pH, osmosis, ions, and the blood-brain barrier (BBB) as possible therapeutic targets for cerebral ischemia injury. The molecular pathways which can interacts with particular cellular pathways, participation in neuroinflammation, and possible interaction with additional proteins thought to be involved in the etiology of a stroke. Understanding these pathways offers crucial information on the diverse role of AQPs in cerebral ischemia, paving the door for the development of focused/targeted therapeutics.

Coordination-Driven Nanomedicine Mitigates One-Lung Ventilation-Induced Lung Injury via Radicals Scavenging and Cell Pyroptosis Inhibition

One-lung ventilation (OLV) during thoracic surgery often leads to post-operative complications, yet effective pharmacological interventions are lacking. This study reports a baicalin-based metal-coordination nanomedicine with disulfiram (DSF) co-loading to address one-lung ventilation-induced lung injury and reperfusion injury (OLV-LIRI). Baicalin, known for its robust antioxidant properties, suffers from poor water solubility and stability. Leveraging nanotechnology, baicalin's coordination is systematically explored with seven common metal ions, designing iron/copper-mediated binary coordination nanoparticles to overcome these limitations. The self-assembled nanoparticles, primarily formed through metal coordination and π-π stacking forces, encapsulated DSF, ensuring high colloidal stability in diverse physiological matrices. Upon a single-dose administration via endotracheal intubation, the nanoparticles efficiently accumulate in lung tissues and swiftly penetrate the pulmonary mucosa. Intracellularly, baicalin exhibits free radical scavenging activity to suppress inflammation. Concurrently, the release of Cu2+ and DSF enables the in situ generation of CuET, a potent inhibitor of cell pyroptosis. Harnessing these multifaceted mechanisms, the nanoparticles alleviate lung injury symptoms without notable toxic side effects, suggesting a promising preventive strategy for OLV-LIRI.

Nanocurcumin Decreases Nucleotide-Binding Oligomerization Domain-Like Receptor Family Pyrin Domain-Containing 3 Complex Expressions in An Experimental Testicular Torsion Model

BACKGROUND

Testicular torsion is a surgical emergency leads to severe acute ischemia injuries, and may eventually cause male infertility. The nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domaincontaining 3 (NLRP3) inflammasome is involved in testicular torsion pathophysiology. The aim of this study was to evaluate the effects of nanocurcumin (nCur) on testicular tissue and the NLRP3 inflammasome components.

MATERIALS AND METHODS

In this experimental study, male Wistar rats (n=36) were randomly divided into six equal groups: controls, ischemia-reperfusion (I/R), I/R+nCur (50 or 100 mg/kg thirty minutes before reperfusion), and I/ R+nCur (50 or 100 mg/kg thirty minutes before reperfusion and continued for seven days). The left testis was rotated 720 (2×360) degrees counterclockwise to induce testicular torsion. After two hours of ischemia, detorsion was performed. At the end of treatment, an orchiectomy was carried out. The testis histopathology and the mRNA levels of NLRP3, apoptosis-associated speck-like protein (ASC), and Caspase-1 were evaluated.

RESULTS

Our results revealed that, testicular I/R had a detrimental effect on testis histology such as the number of spermatogonia (14.5 ± 0.57, P<0.001) and the seminiferous tubules epithelium thickness (28.5 ± 11.7, P=0.007). It also significantly increased the expression of the NLRP3 inflammasome components (P<0.001). Treatment with nCur (in both doses) improved testicular damage and significantly reduced the expression of NLRP3 (P=0.007), ASC (P=0.003), and Caspase-1 (P<0.001).

CONCLUSION

These results imply that nCur might be a useful therapeutic strategy in the field of reproductive medicine to diminish the side effects of testicular I/R via its anti-inflammatory properties and may be employed as adjuvant therapy to lessen testicular torsion complications.

Bergapten attenuates hemorrhagic shock induced multi-organ injury by inhibiting NLRP3 inflammasome activation and pyroptosis

OBJECTIVES

Treatment of hemorrhagic shock (HS) induced multi-organ injury remains a challenge. Bergapten (BeG) is a bioactive coumarin-derived compound, and previous articles have suggested that BeG may serve as a prospective therapeutic modality for HS. This study was designed to investigate the efficacy of BeG in the treatment of HS and its underlying mechanisms.

METHODS

In this research, we established a rat model of HS, following which we assessed the protective effects of BeG on HS induced multi-organ injury. Subsequently, we scrutinized the activation of NLRP3 inflammasomes and pyroptosis in damaged organs. Additionally, we conducted examinations of AMPK and the downstream mitophagy pathway in damaged organs. Finally, we established a hypoxia/reoxygenation (H/R) model in HK-2 cells to simulate the in vitro HS process. Following AMPK inhibition with compound C, we evaluated the levels of mitophagy and cellular pyroptosis in BeG-treated HK-2 cells subjected to H/R.

RESULTS

BeG treatment alleviated HS induced multi-organ injury. Subsequent analyses indicated that the therapeutic effects of BeG were related to the attenuation of NLRP3 inflammasome activation and pyroptosis. Additionally, we found BeG treatment stimulated the phosphorylation of AMPK, thereby enhancing mitophagy. Lastly, we found that the inhibition of AMPK in vitro attenuates BeG's enhancement of mitophagy and its suppression of pyroptosis.

CONCLUSION

Our research indicates that BeG has the potential to alleviate multi-organ injury induced by HS. The protective effect of BeG is likely associated with its promotion of mitophagy through AMPK activation, thereby inhibiting NLRP3 inflammasome-mediated pyroptosis.

SNX10 promoted liver IR injury by facilitating macrophage M1 polarization via NLRP3 inflammasome activation

BACKGROUND

Liver ischemia reperfusion (IR) injury is a common cause of liver dysfunction in patients post liver partial resection and liver transplantation. However, the cellular defense mechanisms underlying IR are not well understood. Macrophage mediated sterile inflammation plays critical roles in liver IR injury. Sorting nexin (SNX) 10, a member of the SNX family which functions in regulation of endosomal sorting. This study aimed to explore the role of sorting nexin 10 (SNX10) during liver IR injury with a focus on regulating macrophage function.

METHODS

Both the gene and protein expression levels of SNX10 were analyzed in human specimens from 10 patients undergoing liver partial resection with ischemic insult and in a mouse model of liver IR. The in vivo effects of SNX10 in liver IR injury and sterile inflammation in mice were investigated. Bone marrow derived macrophages (BMDMs) were used to determine the role of SNX10 in modulating macrophage function in vitro.

RESULTS

Increased expression of SNX10 was observed both in human specimens and mice livers post IR. SNX10 knockdown alleviated IR induced sterile inflammation and liver damage in mice. SNX10 promoted M1 polarization of macrophage treated with LPS and facilitated inflammatory response by activating NLRP3 inflammasome.

CONCLUSIONS

We report for the first time that SNX10 is upregulated in IR-stressed livers. SNX10 activation aggravates liver IR injury and sterile inflammation by facilitating macrophage M1 polarization and inflammatory response suggesting SNX10 as a potential therapeutic target for liver IR injury.

Ischemic myocardial inflammatory signaling in starvation versus hypoxia-derived extracellular vesicles: A comparative analysis

Background

Coronary artery disease remains a leading cause of death worldwide. Bone mesenchymal stem cell-derived extracellular vesicles (EVs) have shown promise in the setting of myocardial ischemia. Furthermore, the properties of the EVs can be modified via preconditioning of progenitor cells. Previous research from our lab demonstrated a significant decrease in proinflammatory signaling following treatment with EVs derived from starvation preconditioning of human bone mesenchymal stem cells (MVM EVs) in a porcine model of chronic myocardial ischemia. However, rodent models have demonstrated that the use of EVs derived from hypoxia preconditioning of bone mesenchymal stem cells (HYP EVs) may have extended benefits compared to MVM EVs. This study evaluated the effect of HYP EVs on inflammation in a swine model of chronic myocardial ischemia. We hypothesized that HYP EVs would have a greater anti-inflammatory effect than MVM EVs or saline (CON).

Methods

Yorkshire swine fed a standard diet underwent placement of an ameroid constrictor to the left circumflex artery. Two weeks later, the animals received intramyocardial injection of saline (CON; n = 6), starvation-derived EVs (MVM; n = 10), or hypoxia-derived EVs (HYP; n = 7). After 5 weeks, myocardial perfusion was assessed, and left ventricular myocardial tissue was harvested. Protein expression was measured using immunoblotting. Data were analyzed via the Kruskal-Wallis test or one-way analysis of variance based on the results of a Shapiro-Wilk test. Coronary perfusion was plotted against relative cytokine concentration and analyzed with the Spearman rank-sum test.

Results

HYP EV treatment was associated with decreased expression of proinflammatory markers interleukin (IL)-6 (P = .03), Pro-IL-1ß (P = .01), IL-17 (P < .01), and NOD-like receptor protein 3 (NLRP3; P < .01) compared to CON. Ischemic tissue from the MVM group showed significantly decreased expression of pro-inflammatory markers NLRP3 (P < .01), IL-17 (P < .01), and HLA class II histocompatibility antigen (P < .01) compared to CON. The MVM group also had decreased expression of anti-inflammatory IL-10 (P = .01) compared to CON counterparts. There were no significant differences in expression of tumor necrosis factor-α, interferon-γ, IL-12, Toll-like receptor-2, and nuclear factor kappa-light-chain-enhancer of activated B cells in either group . There was no correlation between coronary perfusion and cytokine concentration in the MVM or HYP groups, either at rest or with pacing.

Conclusions

HYP EVs and MVM EVs appear to result in relative decreases in the degree of inflammation in chronically ischemic swine myocardium, independent of coronary perfusion. It is possible that this observed decrease may partially explain the myocardial benefits seen with both HYP and MVM EV treatment.

Ischemia‒Reperfusion accelerates neointimal hyperplasia via IL-1β-mediated pyroptosis after balloon injury in the rat carotid artery

Background

Ischemia‒reperfusion (IR) is a pathological process that causes secondary damage to blood vessels. However, whether IR can further worsen neointima formation after balloon injury and the detailed mechanism are unclear.

Methods

An in vivo model of balloon injury to the rat carotid artery was established to study the effect of IR following balloon injury on neointima formation. Smooth muscle cells (SMCs) were isolated from rat aortas and exposed to hypoxia-reoxygenation to mimic the IR process in vitro. The in vitro cell model was used to investigate the mechanism of IR-mediated neointima formation after balloon injury, which was further confirmed in an in vivo rat model.

Results

IR aggravated neointima formation in the rat carotid artery 2 weeks after balloon injury compared with that observed in the absence of balloon injury (P < 0.001). Compared with that of normal SMCs in the rat carotid artery, the expression of IL-1β, a key proinflammatory cytokine associated with pyroptosis, was increased more than 3-fold in the IR-induced neointima (P < 0.0001) and contributed to the proliferation and migration of rat primary aortic SMCs (P < 0.0001). This process was alleviated by the antioxidant acetylcysteine (NAC), suggesting its partial dependence on intracellular ROS. In the rat model of IR following balloon injury in the carotid artery, the carotid artery that was locally transfected with AAV carrying sh-IL-1β or sh-caspase-1, which alleviated neointima formation, as indicated by a reduction in intima-media thickness in the rat carotid artery (P < 0.0001).

Conclusion

Our results suggested that IR could promote IL-1β production in SMCs in the carotid artery after balloon injury and aggravate neointimal hyperplasia, which was alleviated by silencing caspase-1/IL-1β signaling in SMCs in the carotid artery. These results suggest that IL-1β may be an effective target to combat IR-related neointima formation.

Differential early response of monocyte/macrophage subsets to intra-operative corticosteroid administration in lung transplantation

Introduction

Lung transplantation often results in primary and/or chronic dysfunctions that are related to early perioperative innate allo-responses where myeloid subsets play a major role. Corticosteroids are administered upon surgery as a standard-of-care but their action on the different myeloid cell subsets in that context is not known.

Methods

To address this issue, we used a cross-circulatory platform perfusing an extracorporeal lung coupled to cell mapping in the pig model, that enabled us to study the recruited cells in the allogeneic lung over 10 hours.

Results

Myeloid cells, i.e. granulocytes and monocytic cells including classical CD14pos and non-classical/intermediate CD16pos cells, were the dominantly recruited subsets, with the latter upregulating the membrane expression of MHC class II and CD80/86 molecules. Whereas corticosteroids did not reduce the different cell subset recruitment, they potently dampened the MHC class II and CD80/86 expression on monocytic cells and not on alveolar macrophages. Besides, corticosteroids induced a temporary and partial anti-inflammatory gene profile depending on cytokines and monocyte/macrophage subsets.

Discussion

This work documents the baseline effects of the standard-of-care corticosteroid treatment for early innate allo-responses. These insights will enable further optimization and improvement of lung transplantation outcomes.

Common Signaling Pathways Involved in Alzheimer's Disease and Stroke: Two Faces of the Same Coin

Alzheimer's disease (AD) and stroke are two interrelated neurodegenerative disorders which are the leading cause of death and affect the neurons in the brain and central nervous system. Although amyloid-β aggregation, tau hyperphosphorylation, and inflammation are the hallmarks of AD, the exact cause and origin of AD are still undefined. Recent enormous fundamental discoveries suggest that the amyloid hypothesis of AD has not been proven and anti-amyloid therapies that remove amyloid deposition have not yet slowed cognitive decline. However, stroke, mainly ischemic stroke (IS), is caused by an interruption in the cerebral blood flow. Significant features of both disorders are the disruption of neuronal circuitry at different levels of cellular signaling, leading to the death of neurons and glial cells in the brain. Therefore, it is necessary to find out the common molecular mechanisms of these two diseases to understand their etiological connections. Here, we summarized the most common signaling cascades including autotoxicity, ApoE4, insulin signaling, inflammation, mTOR-autophagy, notch signaling, and microbiota-gut-brain axis, present in both AD and IS. These targeted signaling pathways reveal a better understanding of AD and IS and could provide a distinguished platform to develop improved therapeutics for these diseases.

MicroRNA-146a Improved Acute Lung Injury Induced by hepatic Ischemia-reperfusion Injury by Inhibiting PRDX1

Hepatic ischemia-reperfusion injury (HIRI)-induced acute lung injury (ALI) is characterized by high incidence and poor prognosis. The regulatory role of microRNA-146a (miR-146a) in HIRI has been reported, but if miR-146a could affect the progression of HIRI-induced ALI has not been reported. The mice HIRI model was established by ligating left hepatic portal vein and hepatic artery for 60 minutes and then treating with reperfusion for 4 hours. Hypoxia-reoxygenation (HR) was performed to establish cell model. The binding site between miR-146a and Peroxidase 1 (PRDX1) was predicted and validated. The levels of inflammation factors and redox markers were detected with commercial kits. Significant lower expression of miR-146a and higher expression of PRDX1 in HIRI animal model were observed. miR-146a inhibited the liver injury after HIRI induction through targeting PRDX1. miR-146a inhibited the lung injury caused by HIRI via regulating PRDX1. The inhibition of cell apoptosis and inflammation factors by miR-146a were reversed by pcDNA-PRDX1. This research demonstrated that miR-146a improved ALI caused by HIRI by inhibiting apoptosis, inflammation, oxidative condition through targeting PRDX1. This study might provide a novel thought for the prevention and treatment of ALI caused by HIRI by regulating miR-146a/PRDX1 axis.

Sodium Danshensu Cream Promotes the Healing of Pressure Ulcers in Mice through the Nrf2/HO-1 and NF-κB Pathways

On the basis of the mice pressure ulcers (PU) model, the protective effect and potential mechanism of sodium Danshensu (SDSS) cream against PU were investigated. The mice were randomly divided into three groups: the negative control group (cream without 0.5 g SDSS), the SDSS group (cream containing 0.5 g SDSS), and the positive group (0.5 g Hirudoid®). After 7 and 14 days of ointment application, the wound-healing rate of the SDSS and positive groups was significantly higher than that of the control group (p < 0.05). The results of hematoxylin−eosin staining also indicated that SDSS has the potential to promote the healing of PU. In addition, the serum IL-6, IL-1β, TNF-α, and MDA levels decreased significantly (p < 0.01) after 14 days of SDSS treatment, while the SOD, CAT, and GSH-Px activities increased significantly (p < 0.01). In addition, SDSS cream was able to significantly increase the expression of Nrf2, HO-1, GCLM, NQO1, NF-κB p65, NF-κB p50, IKKα, and IKKβ while decreasing the expression of Keap1 and IκBαin the Nrf2/HO-1 and NF-κB pathways. Our research will provide a foundation for the future clinical prevention and treatment of PU with SDSS cream.

Nrf2 Regulates Oxidative Stress and Its Role in Cerebral Ischemic Stroke

Cerebral ischemic stroke is characterized by acute ischemia in a certain part of the brain, which leads to brain cells necrosis, apoptosis, ferroptosis, pyroptosis, etc. At present, there are limited effective clinical treatments for cerebral ischemic stroke, and the recovery of cerebral blood circulation will lead to cerebral ischemia-reperfusion injury (CIRI). Cerebral ischemic stroke involves many pathological processes such as oxidative stress, inflammation, and mitochondrial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2), as one of the most critical antioxidant transcription factors in cells, can coordinate various cytoprotective factors to inhibit oxidative stress. Targeting Nrf2 is considered as a potential strategy to prevent and treat cerebral ischemia injury. During cerebral ischemia, Nrf2 participates in signaling pathways such as Keap1, PI3K/AKT, MAPK, NF-κB, and HO-1, and then alleviates cerebral ischemia injury or CIRI by inhibiting oxidative stress, anti-inflammation, maintaining mitochondrial homeostasis, protecting the blood-brain barrier, and inhibiting ferroptosis. In this review, we have discussed the structure of Nrf2, the mechanisms of Nrf2 in cerebral ischemic stroke, the related research on the treatment of cerebral ischemia through the Nrf2 signaling pathway in recent years, and expounded the important role and future potential of the Nrf2 pathway in cerebral ischemic stroke.