Propofol ameliorates endotoxin‑induced myocardial cell injury by inhibiting inflammation and apoptosis via the PPARγ/HMGB1/NLRP3 axis

Propofol Inhibits Ferroptotic Cell Death Through the Nrf2/Gpx4 Signaling Pathway in the Mouse Model of Cerebral Ischemia-Reperfusion Injury

Ferroptosis is characterized by excessive accumulation of iron and lipid peroxides, which are involved in ischemia, reperfusion-induced organ injury, and stroke. Propofol, an anesthetic agent, has neuroprotective effects due to its potent antioxidant, anti-ischemic, and anti-inflammatory properties. However, the relationship between propofol and ferroptosis is still unclear. In the current study, we elucidated the role of ferroptosis in the neuroprotective effect of propofol in mouse brains subjected to cerebral ischemia reperfusion injury (CIRI). Ferroptosis was confirmed by Western blotting assays, transmission electron microscopy, and glutathione assays. Propofol regulated Nrf2/Gpx4 signaling, enhanced antioxidant potential, inhibited the accumulation of lipid peroxides in CIRI-affected neurons, and significantly reversed CIRI-induced ferroptosis. Additionally, Gpx4 inhibitor RSL3 and Nrf2 inhibitor ML385 attenuated the effects of propofol on antioxidant capacity, lipid peroxidation, and ferroptosis in CIRI-affected neurons. Our data support a protective role of propofol against ferroptosis as a cause of cell death in mice with CIRI. Propofol protected against CIRI-induced ferroptosis partly by regulating the Nrf2/Gpx4 signaling pathway. These findings may contribute to the development of future therapies targeting ferroptosis induced by CIRI.

Saroglitazar, a dual PPAR-α/γ agonist, alleviates LPS-induced hepatic and renal injury in rats

BACKGROUND

Lipopolysaccharide (LPS), an endotoxin within gram-negative bacteria, is associated with systemic acute inflammatory response after invading living tissues and results in sepsis. The liver and kidney are both major target organs in sepsis. Septic acute hepatic-renal injury is a serious clinical condition with high risk of morbidity and mortality. Nevertheless, effective treatment is still lacking.

AIM

This study highlights saroglitazar (SAR), a dual PPAR-α/γ agonist, as a proposed prophylactic drug against LPS-induced hepatic-renal injury.

MAIN METHODS

Rats were pretreated with SAR (2 and 4 mg/kg/day) for 15 days, while sepsis was induced by LPS injection (10 mg/kg) on day 15 one hour following SAR oral administration.

KEY FINDINGS

SAR pretreatment could successfully mitigate LPS-induced hepatic-renal injury, evidenced by enhancement of renal and hepatic functions and a decrease of tissue pathological injury. Meanwhile, SAR alleviated LPS-induced oxidative stress; it reduced malondialdehyde (MDA) levels and ameliorated decreased levels of superoxide dismutase (SOD) and glutathione (GSH). LPS-induced elevations in hepatic and renal nuclear factor-kappa B (NF-κB), phosphorylated inhibitor of kappa B alpha (p-IκBα), interferon-beta (IFN-β), and hepatic high mobility group box-1 (HMGB-1) contents were significantly attenuated in SAR-treated groups. SAR showed an advantageous impact against LPS-induced activation of non-canonical inflammasome and pyroptosis via a significant reduction in cysteinyl aspartate-specific proteinase-11 (Caspase-11) and gasdermin D (GSDMD) expressions. Moreover, Nucleotide-Binding Oligomerization Domain (NOD)-Like Receptor Protein 3 (NLRP3) inflammasome activation with concomitant expression and activation of caspase-1 and release of interleukin-1beta (IL-1β) were considerably diminished following SAR pretreatment.

SIGNIFICANCE

SAR could be considered a prophylactic anti-inflammatory antioxidant drug against LPS-induced liver and kidney injury.

TSPO knockdown attenuates OGD/R-induced neuroinflammation and neural apoptosis by decreasing NLRP3 inflammasome activity through PPARγ pathway

Ischemic stroke is a cerebrovascular disease which is related to brain function loss induced by cerebral ischemia. Translocator protein (TSPO) is an important regulator in inflammatory diseases, while its role in ischemic stroke remains largely unknown. This research aimed to explore the role and action mechanism of TSPO in oxygen-glucose deprivation/reperfusion (OGD/R)-induced neuron cell damage. The differentially expressed genes in ischemic stroke were predicted using GSE140275 dataset, DisGeNet, and GeneCards databases. Differentiated SH-SY5Y cells and primary neurons were subjected to transfection, and stimulated with OGD/R or MCC950 (NLRP3 inhibitor). Proteins were detected by western blotting and ELISA. Cell apoptosis was evaluated through CCK-8, caspase-3 activity and TUNEL assays. TSPO was upregulated in ischemic stroke and in SH-SY5Y cells and primary neurons after OGD/R treatment. TSPO silencing attenuated OGD/R-induced inflammation and apoptosis by decreasing NLRP3 inflammasome activity. TSPO downregulation increased PPARγ expression and decreased HMGB1 expression in OGD/R-treated cells, which was reversed by silencing PPARγ. PPARγ knockdown abolished the effect of TSPO silence on NLRP3 inflammasome activity, inflammation, and cell apoptosis in OGD/R-treated cells, while PPARγ overexpression alleviated OGD/R-induced injury in SH-SY5Y cells. In conclusion, TSPO knockdown attenuates neuroinflammation and neural apoptosis by decreasing NLRP3 inflammasome activity through PPARγ pathway.

Mechanism of miR-126 in hypoxia-reoxygenation-induced cardiomyocyte pyroptosis by regulating HMGB1 and NLRP3 inflammasome

OBJECTIVE

Pyroptosis refers to the programmed cell death. This study evaluated the mechanism of miR-126 in hypoxia-reoxygenation (HR)-induced cardiomyocyte pyroptosis.

METHODS

The HR rat cardiomyocyte models were established. The cell viability, cytotoxicity, and levels of miR-126, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, gasdermin D (GSDMD), and GSDMD-N were detected. The cells were transfected with miR-126 mimics to verify the effect on rat cardiomyocyte pyroptosis, and added with HMGB1 inhibitor (Glycyrrhizin) or NLRP3 inhibitor (S3680) to explore the regulatory mechanisms on rat cardiomyocyte pyroptosis. The binding relationship of miR-126 and HMGB1 was explored. The regulatory effect of miR-126 and HMGB1 on HR-stimulated cardiomyocytes was verified through co-transfection with miR-126 mimics and pcDNA3.1-HMGB1.

RESULTS

HR treatment inhibited rat cardiomyocyte viability and increased cytotoxicity. After HR treatment, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, GSDMD, and GSDMD-N were elevated in rat cardiomyocytes, while miR-126 was evidently downregulated in rat cardiomyocytes. miR-126 overexpression, and inhibition of HMGB1 or NLRP3 partially reversed HR-induced rat cardiomyocyte cytotoxicity and pyroptosis. miR-126 targeted HMGB1 and HMGB1 overexpression partly reversed the inhibition of miR-126 overexpression on HR-induced cardiomyocyte pyroptosis.

CONCLUSION

miR-126 inhibits HMGB1/NLRP3 activity and the caspase-1/11 activation and reduces the GSDMD-N cleaved from GSDMD, ultimately inhibiting HR-induced cardiomyocyte pyroptosis.

Post‑treatment with propofol inhibits inflammatory response in LPS‑induced alveolar type II epithelial cells

Over-inflammation and severe lung injury are major causes of morbidity and mortality in patients with coronavirus disease 2019 (COVID-19). With the COVID-19 pandemic, an increasing number of patients with preexisting lung injury and inflammation are undergoing surgery or artificial ventilation under sedation in intensive care units, where 2,6-diisopropylphenol (propofol) is a commonly used drug for sedation. The aim of the present study was to investigate whether post-inflammation treatment with propofol protects epithelial type II cells against inflammation in an in vitro model of inflammation. The A549 cell line, characterised as epithelial type II cells, were exposed to lipopolysaccharide (LPS) for 2 h and subsequently treated with different concentrations of propofol (0, 10, 25 or 50 µM) for 3 h. Western blot and reverse transcription-quantitative PCR analyses were used to detect the protein and mRNA expression levels, respectively, of CD14 and Toll-like receptor 4 (TLR4). Immunofluorescence staining was used to detect the in situ CD14 and TLR4 expression in epithelial type II cells. Tumor necrosis factor (TNF)-α production was also examined using ELISA. LPS significantly increased the expression of CD14 and TLR4, as well as the secretion of TNF-α. Post-treatment with 25 and 50 µM propofol of the LPS-treated cells significantly decreased CD14 and TLR4 expression, as well as TNF-α secretion, compared with the cells treated with LPS only, indicating that post-treatment with propofol alleviated inflammation and this effect was dose-dependent. The present study suggested that treatment with propofol after LPS administration has a protective effect on epithelial type II cells.

Dapagliflozin Alleviates Renal Fibrosis by Inhibiting RIP1-RIP3-MLKL-Mediated Necroinflammation in Unilateral Ureteral Obstruction

Dapagliflozin, a sodium-glucose cotransporter-2 inhibitor, offers renoprotection in diabetes. However, potential for use in nondiabetic kidney disease remains unknown. Herein, we assessed whether dapagliflozin alleviates renal fibrosis by interfering with necroinflammation in a rat model of unilateral ureteral obstruction (UUO) and in vitro. After induction of UUO, rats were administered dapagliflozin daily for seven consecutive days. UUO induced significant renal tubular necrosis and overexpression of RIP1-RIP3-MLKL axis proteins; these coincided with NLRP3 inflammasome activation, and subsequent development of renal fibrosis. Oxidative stress caused by UUO is tightly associated with endoplasmic reticulum stress and mitochondrial dysfunction, leading to apoptotic cell death through Wnt3α/β-catenin/GSK-3β signaling; all of which were abolished by both dapagliflozin and specific RIP inhibitors (necrostatin-1 and GSK872). In H₂O₂-treated HK-2 cells, dapagliflozin and RIP inhibitors suppressed overexpression of RIP1-RIP3-MLKL proteins and pyroptosis-related cytokines, decreased intracellular reactive oxygen species production and apoptotic cell death, whereas cell viability was improved. Moreover, activated Wnt3α/β-catenin/GSK-3β signaling was inhibited by dapagliflozin and Wnt/β-catenin inhibitor ICG-001. Our findings suggest that dapagliflozin ameliorates renal fibrosis by inhibiting RIP1-RIP3-MLKL-mediated necroinflammation via Wnt3α/β-catenin/GSK-3β signaling in UUO.

Antifungal Activity of a Neodymium-Doped Yttrium Aluminum Garnet 1,064-Nanometer Laser against Sporothrix globosa by Inducing Apoptosis and Pyroptosis via the NLRP3/Caspase-1 Signaling Pathway: In Vitro and In Vivo Study

Sporotrichosis is a deep fungal infection caused by Sporothrix species. Currently, itraconazole is the main treatment, but fungal resistance, adverse effects, and drug interactions remain major concerns, especially in patients with immune dysfunction. Therefore, an alternative treatment is greatly in demand. This animal study aimed to investigate the inhibitory effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) 1,064-nm laser treatment on Sporothrix globosa and to explore whether it happens through regulation of the Nod-like receptor thermoprotein domain-related protein 3 (NLRP3)/caspase-1 pyroptosis and apoptosis pathway. After laser irradiation, a series of studies, including assays of viability (using the cell counting kit-8 [CCK-8]), morphological structure changes, reactive oxygen species (ROS) accumulation, mitochondrial membrane potential, oxidative stress, cell cycle progression, and metacaspase activation, were conducted to estimate the effect of Nd:YAG 1,064-nm laser treatment on Sporothrix globosa cell apoptosis in vitro. For in vivo studies, mice were infected with S. globosa and then treated with laser or itraconazole, and their footpad skin lesions and the changes in the histology of tissue samples were compared. In addition, changes in the levels of NLRP3, caspase-1, and caspase-3 were assessed by immunohistochemistry, while the levels of interleukin 17 (IL-17), interferon gamma (IFN-γ), and transforming growth factor β1 (TGF-β1) in peripheral blood were tested by enzyme-linked immunosorbent assay (ELISA). The in vitro growth of S. globosa was inhibited and apoptosis was observed after laser treatment. According to the in vivo studies, the efficacy of the laser treatment was similar to that of itraconazole. Moreover, the NLRP3/caspase-1 pyroptosis pathway was activated, with a Th1/Th17 cell response, and the expression of caspase-3 was also upregulated. Nd:YAG 1,064-nm laser treatment can effectively inhibit the growth of S. globosa by activating fungal apoptosis and pyroptosis through the NLRP3/caspase-1 pathway. Therefore, Nd:YAG 1,064-nm laser irradiation is an alternative for sporotrichosis therapy.

IMPORTANCE Nd:YAG 1,064-nm laser irradiation is a useful alternative for the treatment of sporotrichosis, especially in patients with liver dysfunction, pregnant women, and children, for whom the administration of antifungal drugs is not suitable. It may improve the overall treatment effect by shortening the duration of antifungal treatment and reducing tissue inflammation.

Cardioprotective activity of ethyl acetate extract of Cinnamomi Ramulus against myocardial ischemia/reperfusion injury in rats via inhibiting NLRP3 inflammasome activation and pyroptosis

BACKGROUND

NLRP3 inflammasome activation and pyroptosis play an important role in myocardial ischemia/reperfusion injury (MI/RI). Cinnamomi ramulus (CR), is an important folk medicinal plant in China, which derived from the dried twig of Cinnamomum cassia (L.) Presl, has function of "warming and tonifying heart yang", and traditionally utilized to treat the cold, blood-cold amenorrhea, phlegm, edema, arthralgia, and palpitations as well as improve blood circulation. The aqueous extract of C. ramulus was reported to show significant therapeutic potential for treating MI/RI. Whereas, there are no previous investigations in China or abroad has reported the cardioprotective effects and underlying mechanism of the ethyl acetate extract of C. ramulus (CREAE) and its bioactive substance cinnamic acid (CA) in triggering NLRP3 inflammasome activation and subsequent pyroptosis.

PURPOSE

The present study aimed to assess the cardioprotective function of CREAE and CA against the MI/RI in rats and involved the underlying mechanisms.

METHODS

The MI/RI model was established in male SD rats by occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min, respectively. The rats were intragastrically administered with CREAE (74 and 37 mg/kg) and CA (45 mg/kg) for 7 successive days before vascular ligation. The cardioprotective effects of CREAE and CA against myocardial injury of rats were detected by HE staining, TTC staining, echocardiograms, and myocardial enzymes detections. Serum levels of inflammatory factors, such as IL-6, IL-1β, and TNF-α, were analyzed by ELISA kits to evaluate the effects of CREAE and CA. The protein and gene expression levels of NLRP3 and the pyroptosis-related factors in heart tissue were conducted by western blot and RT-qPCR.

RESULTS

Our results showed that CREAE and CA decrease myocardial infarct size and improve cardiac function, mitigate myocardial damage, and repress inflammatory response in rats after I/R. Mechanistically, our results revealed that CREAE and CA can dramatically suppress the activation of NLRP3 inflammasome and subsequent cardiomyocyte pyroptosis in myocardial tissues that as evidenced by downregulating the protein and gene expressions of NLRP3, ASC, IL-1β, caspase-1, gasdermin D, and N-terminal GSDMD.

CONCLUSIONS

Our data indicated that CREAE and CA may attenuate MI/RI through suppression of NLRP3 inflammasome and subsequent pyroptosis-related signaling pathways.