Pathogen-associated molecular patterns and extracellular Hsp70 interplay in NLRP3 inflammasome activation in monocytic and bronchial epithelial cellular models of COPD exacerbations

Assessment of NLRP3 inflammasome activation in patients with chronic obstructive pulmonary disease before and after lung transplantation

The interplay between purinergic receptors as well as pattern recognition receptors like Toll-like receptors (TLRs) and NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) might have a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to determine and compare the concentrations of the damage-associated molecular patterns (DAMPs) heat shock protein 70 (Hsp70) and adenosine triphosphate (ATP), and gene expression of their respective receptors as well as NLRP3 inflammasome-related molecules in the peripheral blood of patients with end-stage COPD before and 1 year after lung transplantation (LT). Lung function was assessed by spirometry and diffusion capacity for carbon monoxide (DLCO). Quantitative polymerase chain reaction (qPCR) was applied for detection of TLR2, TLR4, P2X7R, P2Y2R, IL1B, CASP1, and NLRP3 expression. High-sensitivity ELISA kits were used for extracellular (e) Hsp70 and IL-1β, and luminescence assay for eATP measurements. Concentrations of eHsp70 and eATP as well as IL-1β were significantly increased in the plasma of end-stage COPD patients and significantly decreased after LT. In addition, TLR4, P2Y2R, IL1B, CASP1, and NLRP3 expression was up-regulated in COPD patients before LT, while it was significantly suppressed after LT. In conclusion, it could be assumed that NLRP3 inflammasome is activated in the peripheral blood of end-stage COPD patients and that eHsp70 and eATP could be responsible for its activation through triggering their receptors. On the other hand, previously enhanced pro-inflammatory reactions seem to be suppressed to the healthy population levels in lung recipients without allograft rejection.

Renoprotective effect of diacetylrhein on diclofenac-induced acute kidney injury in rats via modulating Nrf2/NF-κB/NLRP3/GSDMD signaling pathways

Diclofenac (DF)-induced acute kidney injury (AKI) is characterized by glomerular dysfunction and acute tubular necrosis. Due to limited treatment approaches, effective and safe drug therapy to protect against such AKI is still needed. Diacetylrhein (DAR), an anthraquinone derivative, has different antioxidant and anti-inflammatory properties. Therefore, the aim of the current study was to investigate the renoprotective effect of DAR on DF-induced AKI while elucidating the potential underlying mechanism. Our results showed that DAR (50 and 100 mg/kg) markedly abrogated DF-induced kidney dysfunction decreasing SCr, BUN, serum NGAL, and serum KIM1 levels. Moreover, DAR treatment remarkably maintained renal redox balance and reduced the levels of pro-inflammatory biomarkers in the kidney. Mechanistically, DAR boosted Nrf2/HO-1 antioxidant and anti-inflammatory response in the kidney while suppressing renal TLR4/NF-κB and NLRP3/caspase-1 inflammatory signaling pathways. In addition, DAR markedly inhibited renal pyroptosis via targeting of GSDMD activation. Collectively, this study confirmed that the interplay between Nrf2/HO-1 and TLR4/NF-κB/NLRP3/Caspase-1 signaling pathways and pyroptotic cell death mediates DF-induced AKI and reported that DAR has a dose-dependent renoprotective effect on DF-induced AKI in rats. This effect is due to powerful antioxidant, anti-inflammatory, and anti-pyroptotic activities that could provide a promising treatment approach to protect against DF-induced AKI.

Electrospun nanofibers synthesized from polymers incorporated with bioactive compounds for wound healing

The development of innovative wound dressing materials is crucial for effective wound care. It's an active area of research driven by a better understanding of chronic wound pathogenesis. Addressing wound care properly is a clinical challenge, but there is a growing demand for advancements in this field. The synergy of medicinal plants and nanotechnology offers a promising approach to expedite the healing process for both acute and chronic wounds by facilitating the appropriate progression through various healing phases. Metal nanoparticles play an increasingly pivotal role in promoting efficient wound healing and preventing secondary bacterial infections. Their small size and high surface area facilitate enhanced biological interaction and penetration at the wound site. Specifically designed for topical drug delivery, these nanoparticles enable the sustained release of therapeutic molecules, such as growth factors and antibiotics. This targeted approach ensures optimal cell-to-cell interactions, proliferation, and vascularization, fostering effective and controlled wound healing. Nanoscale scaffolds have significant attention due to their attractive properties, including delivery capacity, high porosity and high surface area. They mimic the Extracellular matrix (ECM) and hence biocompatible. In response to the alarming rise of antibiotic-resistant, biohybrid nanofibrous wound dressings are gradually replacing conventional antibiotic delivery systems. This emerging class of wound dressings comprises biopolymeric nanofibers with inherent antibacterial properties, nature-derived compounds, and biofunctional agents. Nanotechnology, diminutive nanomaterials, nanoscaffolds, nanofibers, and biomaterials are harnessed for targeted drug delivery aimed at wound healing. This review article discusses the effects of nanofibrous scaffolds loaded with nanoparticles on wound healing, including biological (in vivo and in vitro) and mechanical outcomes.

Human umbilical cord mesenchymal stem cell-derived exosomes attenuate neuroinflammation and oxidative stress through the NRF2/NF-κB/NLRP3 pathway

AIMS

We investigated whether human umbilical cord mesenchymal stem cell (hUC-MSC)-derived exosomes bear therapeutic potential against lipopolysaccharide (LPS)-induced neuroinflammation.

METHODS

Exosomes were isolated from hUC-MSC supernatant by ultra-high-speed centrifugation and characterized by transmission electron microscopy and western blotting. Inflammatory responses were induced by LPS in BV-2 cells, primary microglial cultures, and C57BL/6J mice. H2 O2 was also used to induce inflammation and oxidative stress in BV-2 cells. The effects of hUC-MSC-derived exosomes on inflammatory cytokine expression, oxidative stress, and microglia polarization were studied by immunofluorescence and western blotting.

RESULTS

Treatment with hUC-MSC-derived exosomes significantly decreased the LPS- or H2 O2 -induced oxidative stress and expression of pro-inflammatory cytokines (IL-6 and TNF-α) in vitro, while promoting an anti-inflammatory (classical M2) phenotype in an LPS-treated mouse model. Mechanistically, the exosomes increased the NRF2 levels and inhibited the LPS-induced NF-κB p65 phosphorylation and NLRP3 inflammasome activation. In contrast, the reactive oxygen species scavenger NAC and NF-κB inhibitor BAY 11-7082 also inhibited the LPS-induced NLRP3 inflammasome activation and switched to the classical M2 phenotype. Treatment with the NRF2 inhibitor ML385 abolished the anti-inflammatory and anti-oxidative effects of the exosomes.

CONCLUSION

hUC-MSC-derived exosomes ameliorated LPS/H2 O2 -induced neuroinflammation and oxidative stress by inhibiting the microglial NRF2/NF-κB/NLRP3 signaling pathway.

Nrf2/HO-1 signaling activation alleviates cigarette smoke-induced inflammation in chronic obstructive pulmonary disease by suppressing NLRP3-mediated pyroptosis

BACKGROUND

This study examined the effect of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway on chronic obstructive pulmonary disease (COPD) and the potential molecular mechanism.

METHODS

A COPD mouse model was established by cigarette smoke exposure and administered with either ML385 or dimethyl fumarate (DMF). Airway resistance of mice was detected. IL-1β and IL-6 levels in mice alveolar lavage fluid were examined by enzyme-linked immunosorbent assay. Hematoxylin and eosin staining and immunohistochemical of lung tissues were utilized to detect lung injury and NLRP3 expression. DMF was used to treat COPD cell model constructed by exposing normal human bronchial epithelial (NHBE) cells to cigarette smoke extract. NHBE cells were transfected by NLRP3-expression vectors. Expression of proteins was detected by Western blot.

RESULTS

COPD mice showed the enhanced airway resistance, the inactivated Nrf2/HO-1 pathway and the overexpressed NLRP3, Caspase-1 and GSDMD-N proteins in lung tissues, and the increased IL-1β and IL-6 levels in alveolar lavage fluid. ML385 treatment augmented these indicators and lung injury in COPD mice. However, DMF intervention attenuated these indicators and lung injury in COPD mice. Nrf2/HO-1 pathway inactivation and overexpression of NLRP3, Caspase-1 and GSDMD-N proteins were observed in COPD cells. DMF intervention activated Nrf2/HO-1 pathway and down-regulated NLRP3, Caspase-1 and GSDMD-N proteins in COPD cells. However, NLRP3 overexpression abolished the effect of DMF on COPD cells.

CONCLUSION

Nrf2/HO-1 pathway activation may alleviate inflammation in COPD by suppressing the NLRP3-related pyroptosis. Activating the Nrf2/HO-1 pathway may be an effective method to treat COPD.

Rosuvastatin and diosmetin inhibited the HSP70/TLR4 /NF-κB p65/NLRP3 signaling pathways and switched macrophage to M2 phenotype in a rat model of acute kidney injury induced by cisplatin

Numerous efforts to manage acute kidney injury (AKI) were unsuccessful because its pathophysiology is still poorly understood. Thus, our research hotspot was to explore the possible renoprotective effects of rosuvastatin (Ros) and diosmetin (D) on macrophage polarization and the role of HSP70/TLR4/MyD88/NF-κB p65/NLRP3/STAT3 signaling in cis-induced AKI and study the activity of D against uropathogenic bacteria. Fifty-four albino male rats were randomized into 9 groups equally: Control, Ros, D20, D40, untreated Cis, and Cis groups cotreated with Ros, D20, D40 and Ros+D40 for 10 days. Our results indicated that Ros and D, in a dose-dependent manner, markedly restored body weight, systolic blood pressure, and renal histological architecture besides significantly upregulated SOD levels, expression of anti-inflammatory CD163 macrophages, arginase1levels, IL-10 levels,STAT3 and PCNA immunoreactivity. Also, they significantly downregulated renal index, serum urea, serum creatinine, serum cystatin c, inflammatory biomarkers (C reactive protein, IL1β & TNF-α), MDA levels, HSP70/TLR4/MyD88/NF-κB p65/NLRP3 expressions, proinflammatory CD68 macrophages and caspase-3 immunoreactivity, resulting in a reversal of cis-induced renal damage. These findings were further confirmed by molecular docking that showed the binding affinity of Ros and D towards TLR4 and NLRP3. Furthermore, D had antibacterial action with a minimum inhibitory concentration ranging from 128 to 256 µg/mL and caused a delay in the growth of the tested isolates, and negatively affected the membrane integrity. In conclusion, Ros and D had antioxidant, anti-inflammatory and antiapoptotic properties and switched macrophage from proinflammatory CD68 to anti-inflammatory CD163. Additionally, the targeting of HSP70/TLR4/MyD88/NF-κB p65/NLRP3/STAT3 signals are effective therapeutic strategy in AKI.

Modulation of chronic obstructive pulmonary disease progression by antioxidant metabolites from Pediococcus pentosaceus: enhancing gut probiotics abundance and the tryptophan-melatonin pathway

Chronic obstructive pulmonary disease (COPD), a condition primarily linked to oxidative stress, poses significant health burdens worldwide. Recent evidence has shed light on the association between the dysbiosis of gut microbiota and COPD, and their metabolites have emerged as potential modulators of disease progression through the intricate gut-lung axis. Here, we demonstrate the efficacy of oral administration of the probiotic Pediococcus pentosaceus SMM914 (SMM914) in delaying the progression of COPD by attenuating pulmonary oxidative stress. Specially, SMM914 induces a notable shift in the gut microbiota toward a community structure characterized by an augmented abundance of probiotics producing short-chain fatty acids and antioxidant metabolisms. Concurrently, SMM914 synthesizes L-tryptophanamide, 5-hydroxy-L-tryptophan, and 3-sulfino-L-alanine, thereby enhancing the tryptophan-melatonin pathway and elevating 6-hydroxymelatonin and hypotaurine in the lung environment. This modulation amplifies the secretion of endogenous anti-inflammatory factors, diminishes macrophage polarization toward the M1 phenotype, and ultimately mitigates the oxidative stress in mice with COPD. The demonstrated efficacy of the probiotic intervention, specifically with SMM914, not only highlights the modulation of intestine microbiota but also emphasizes the consequential impact on the intricate interplay between the gastrointestinal system and respiratory health.

Drug repurposing screens to identify potential drugs for chronic kidney disease by targeting prostaglandin E2 receptor

Renal inflammation and fibrosis are significantly correlated with the deterioration of kidney function and result in chronic kidney disease (CKD). However, current therapies only delay disease progression and have limited treatment effects. Hence, the development of innovative therapeutic approaches to mitigate the progression of CKD has become an attractive issue. To date, the incidence of CKD is still increasing, and the biomarkers of the pathophysiologic processes of CKD are not clear. Therefore, the identification of novel therapeutic targets associated with the progression of CKD is an attractive issue. It is a critical necessity to discover new therapeutics as nephroprotective strategies to stop CKD progression. In this research, we focus on targeting a prostaglandin E₂ receptor (EP2) as a nephroprotective strategy for the development of additional anti-inflammatory or antifibrotic strategies for CKD. The in silico study identified that ritodrine, dofetilide, dobutamine, and citalopram are highly related to EP2 from the results of chemical database virtual screening. Furthermore, we found that the above four candidate drugs increased the activation of autophagy in human kidney cells, which also reduced the expression level of fibrosis and NLRP3 inflammasome activation. It is hoped that these findings of the four candidates with anti-NLRP3 inflammasome activation and antifibrotic effects will lead to the development of novel therapies for patients with CKD in the future.

GSPE attenuates CSE-induced lung inflammation and emphysema by regulating autophagy via the reactive oxygen species/TFEB signaling pathway

Cigarette smoke can enhance reactive oxygen species (ROS) production in inflammatory and epithelial cells. Subsequently, ROS enhance autophagy-induced inflammation due to alveolar macrophages (AMs), the primary source of cytokines implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. Therefore, we hypothesized that grape seed proanthocyanidin extract (GSPE), an effective antioxidant, could inhibit emphysema and airway inflammation by ameliorating cigarette smoke extract (CSE)-induced autophagy via suppressing oxidative stress in macrophages. We observed that GSPE significantly attenuated histological changes observed in CSE-induced emphysema and airway inflammation in the lungs of mice. Moreover, GSPE ameliorated lung inflammation by reducing the number of cells, macrophages, and neutrophils and the tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels measured in bronchioloalveolar lavage fluid. ROS levels increased after CSE instillation and significantly decreased with in vitro GSPE treatment. GSPE decreased transcription factor EB (TFEB) oxidation by reducing ROS, inhibiting TFEB nuclear translocation. Furthermore, GSPE inhibited ROS-induced autophagy in RAW 264.7 cells, bone marrow-derived macrophages, and AMs. Inhibiting autophagy through GSPE treatment diminishes CSE-induced lung inflammation by inhibiting the NLRP3 inflammasome. This study demonstrates that GSPE can ameliorate CSE-induced inflammation and emphysema via autophagy-induced NLRP3 inflammasome regulation through the ROS/TFEB signaling pathway in a COPD mouse model.

Low-intensity pulsed ultrasound (LIPUS) switched macrophage into M2 phenotype and mitigated necroptosis and increased HSP 70 in gentamicin-induced nephrotoxicity

BACKGROUND AND AIM

Many attempts to control acute kidney injury (AKI) have failed due to a lack of understanding of its pathophysiological key components. Macrophages are a crucial determinant of AKI, which can be categorized functionally as M1 pro-inflammatory and M2 anti-inflammatory macrophages. Low-intensity pulsed ultrasound (LIPUS) is currently being investigated as an immune modulator. The present study aimed to explore the potential effects of LIPUS on the polarization of renal macrophages, as well as the possible interplay between macrophage polarization and necroptosis in gentamicin-induced acute kidney injury.

METHOD

All rats were randomly allocated into one of four groups: control, LIPUS-treated control, gentamicin acute kidney (GM-AKI), and LIPUS-treated GM-AKI. Renal functions, macrophage polarization, necroptosis, and heat shock protein-70 (HSP70) were analyzed using real-time reverse-transcriptase-polymerase chain reaction (rT-PCR), Western Blot, Enzyme-linked immunosorbent assay (ELISA) as well as immunohistological analysis.

RESULTS

we found that LIPUS markedly inhibited the expressions of M1 macrophage-related genes and promoted significantly the expression of M2 macrophages related genes. This was accompanied by an inhibition of necroptosis and a marked reduction of HSP-70, resulting in a reversal of gentamicin-induced renal alteration.

CONCLUSION

Functional switching of macrophage responses from M1 into M2 seems to be a potential approach to ameliorate necroptosis as well as HSP-70 by low pulsed ultrasound waves in GM-AKI.

HSP70 alleviates sepsis-induced cardiomyopathy by attenuating mitochondrial dysfunction-initiated NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes

BACKGROUND

Sepsis-induced cardiomyopathy (SIC) is an identified serious complication of sepsis that is associated with adverse outcomes and high mortality. Heat shock proteins (HSPs) have been implicated in suppressing septic inflammation. The aim of this study was to investigate whether HSP70 can attenuate cellular mitochondrial dysfunction, exuberated inflammation and inflammasome-mediated pyroptosis for SIC intervention.

METHODS

Mice with cecal ligation plus perforation (CLP) and lipopolysaccharide (LPS)-treated H9C2 cardiomyocytes were used as models of SIC. The mouse survival rate, gross profile, cardiac function, pathological changes and mitochondrial function were observed by photography, echocardiography, hematoxylin-eosin staining and transmission electron microscopy. In addition, cell proliferation and the levels of cardiac troponin I (cTnI), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were determined by Cell Counting Kit-8, crystal violet staining and enzyme-linked immunosorbent assay. Moreover, mitochondrial membrane potential was assessed by immunofluorescence staining, and dynamin-related protein 1 and pyroptosis-related molecules [nucleotide-binding domain, leucine-rich-repeat containing family pyrin domain-containing 3 (NLRP3), caspase-1, gasdermin-D (GSDMD), gasdermin-D N-terminal (GSDMD-N)] were measured by western blotting, immunoprecipitation and immunoblotting. Finally, hsp70.1 knockout mice with CLP were used to verify the effects of HSP70 on SIC and the underlying mechanism.

RESULTS

Models of SIC were successfully established, as reduced consciousness and activity with liparotrichia in CLP mice were observed, and the survival rate and cardiac ejection fraction (EF) were decreased; conversely, the levels of cTnI, TNF-α and IL-1β and myocardial tissue damage were increased in CLP mice. In addition, LPS stimulation resulted in a reduction in cell viability, mitochondrial destabilization and activation of NLRP3-mediated pyroptosis molecules in vitro. HSP70 treatment improved myocardial tissue damage, survival rate and cardiac dysfunction caused by CLP. Additionally, HSP70 intervention reversed LPS-induced mitochondrial destabilization, inhibited activation of the NLRP3 inflammasome, caspase-1, GSDMD and GSDMD-N, and decreased pyroptosis. Finally, knockout of hsp70.1 mice with CLP aggravated cardiac dysfunction and upregulated NLRP3 inflammasome activity, and exogenous HSP70 significantly rescued these changes. It was further confirmed that HSP70 plays a protective role in SIC by attenuating mitochondrial dysfunction and inactivating pyroptotic molecules.

CONCLUSIONS

Our study demonstrated that mitochondrial destabilization and NLRP3 inflammasome activation-mediated pyroptosis are attributed to SIC. Interestingly, HSP70 ameliorates sepsis-induced myocardial dysfunction by improving mitochondrial dysfunction and inhibiting the activation of NLRP3 inflammasome-mediated pyroptosis, and such a result may provide approaches for novel therapies for SIC.

Cigarette smoke-induced gasdermin D activation in bronchoalveolar macrophages and bronchial epithelial cells dependently on NLRP3

Chronic pulmonary inflammation and chronic obstructive pulmonary disease (COPD) are major health issues largely due to air pollution and cigarette smoke (CS) exposure. The role of the innate receptor NLRP3 (nucleotide-binding domain and leucine-rich repeat containing protein 3) orchestrating inflammation through formation of an inflammasome complex in CS-induced inflammation or COPD remains controversial. Using acute and subchronic CS exposure models, we found that Nlrp3-deficient mice or wild-type mice treated with the NLRP3 inhibitor MCC950 presented an important reduction of inflammatory cells recruited into the bronchoalveolar space and of pulmonary inflammation with decreased chemokines and cytokines production, in particular IL-1β demonstrating the key role of NLRP3. Furthermore, mice deficient for Caspase-1/Caspase-11 presented also decreased inflammation parameters, suggesting a role for the NLRP3 inflammasome. Importantly we showed that acute CS-exposure promotes NLRP3-dependent cleavage of gasdermin D in macrophages present in the bronchoalveolar space and in bronchial airway epithelial cells. Finally, Gsdmd-deficiency reduced acute CS-induced lung and bronchoalveolar space inflammation and IL-1β secretion. Thus, we demonstrated in our model that NLRP3 and gasdermin D are key players in CS-induced pulmonary inflammation and IL-1β release potentially through gasdermin D forming-pore and/or pyroptoctic cell death.

The Role of the NLRP3 Inflammasome in Mediating Glomerular and Tubular Injury in Diabetic Nephropathy

The NOD-like receptor protein 3 (NLRP3) inflammasome is a multi-protein signalling complex integral to the chronic inflammatory response, activated in response to sterile and non-sterile cellular damage. The assembly and activation of the NLRP3 inflammasome comprise a two-step process involving nuclear factor kappa B (NFkB)-mediated priming, followed by canonical, non-canonical or alternative signalling pathways. These result in the maturation and release of inflammatory cytokines interleukin 1 beta (IL1ß) and interleukin-18 (IL18), which are associated with chronic inflammatory conditions including diabetic kidney disease. Diabetic nephropathy is a condition affecting ∼40% of people with diabetes, the key underlying pathology of which is tubulointerstitial inflammation and fibrosis. There is growing evidence to suggest the involvement of the NLRP3 inflammasome in this chronic inflammation. Early deterioration of kidney function begins in the glomerulus, with tubular inflammation dictating the progression of late-stage disease. Priming and activation of the NLRP3 inflammasome have been linked to several clinical markers of nephropathy including proteinuria and albuminuria, in addition to morphological changes including mesangial expansion. Treatment options for diabetic nephropathy are limited, and research that examines the impact of directly targeting the NLRP3 inflammasome, or associated downstream components are beginning to gain favour, with several agents currently in clinical trials. This review will explore a role for NLRP3 inflammasome activation and signalling in mediating inflammation in diabetic nephropathy, specifically in the glomerulus and proximal tubule, before briefly describing the current position of therapeutic research in this field.

Roles of Inflammasome in Cigarette Smoke-Related Diseases and Physiopathological Disorders: Mechanisms and Therapeutic Opportunities

Cigarette smoke damages a wide range of immunological functions, including innate and adaptive immune responses. Emerging literature demonstrates that inflammasome constitutes an essential component in innate immune response. In this review, we focus on the cumulative mechanisms of inflammasome in cigarette smoke-related diseases and physiopathological disorders, and summarize potential therapeutic opportunities targeting inflammasome. This review suggests that inflammasomes (NLRP3, NLRP6, NLRP12 and AIM2) are involved in the pathogenesis of several cigarette smoke-related diseases (including COPD, ALI, atherosclerosis, kidney injury, bladder dysfunction, and oral leukoplakia) and physiopathological disorders (macrophage dysfunction, endothelial barrier dysfunction, podocyte injury, and ubiquitin-mediated proteasomal processing). MyD88/NF-κB, HMGB1, production of ROS, endoplasmic reticulum stress and mitochondrial dysfunction, and Ca²⁺ influx are potentially involved in cigarette smoke induced-inflammasome activation. Strategies targeting ROS/NLRP3 inflammasome axis are most widely investigated and show potential therapeutic effects.