Streptomyces small laccase expressed in Aspergillus Niger as a new addition for the lignocellulose bioconversion toolbox.

Laccases are multi-copper oxidases that are usually composed of three Cu-oxidase domains. Domains one and three house the copper binding sites, and the second domain is involved in forming a substrate-binding cleft. However, Streptomyces species are found to have small laccases (SLAC) that lack one of the three Cu-oxidase domains. This type of SLAC with interesting lignocellulose bioconversion activities has not been reported in Aspergillus niger. In our research, we explored the expression and engineering of the SLAC from Streptomyces leeuwenhoekii C34 in A. niger. Genes encoding two versions of the SLAC were expressed. One encoding the SLAC in its native form and a second encoding the SLAC fused to two N-terminal CBM1 domains. The latter is a configuration also known for specific yeast laccases. Both SLAC variants were functionally expressed in A. niger as shown by in vitro activity assays and proteome analysis. Laccase activity was also analyzed toward bioconversion of lignocellulosic rice straw. From this analysis it was clear that the SLAC activity improved the efficiency of saccharification of lignocellulosic biomass by cellulase enzyme cocktails.

Yeast ß-glucan alleviates high-fat diet-induced Alzheimer's disease-like pathologies in rats via the gut-brain axis.

Targeting the gut microbiota may be an emerging strategy for the prevention and treatment of Alzheimer's disease (AD). Macro-molecular yeast ß-glucan (BG), derived from the yeast of Saccharomyces cerevisiae, regulates the gut microbiota. This study aimed to investigate the effect and mechanism of long-term BG in high-fat diet (HFD)-induced AD-like pathologies from the perspective of the gut microbiota. Here, we found that 80 weeks of BG treatment ameliorated HFD-induced cognitive dysfunction in rats. In the hippocampus, BG alleviated HFD-induced the activation of astrocytes, microglia, NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome pathway, and AD-like pathologies. BG modulated gut dysbiosis through increasing the levels of beneficial bacteria and short-chain fatty acids (SCFAs). BG also attenuated HFD-induced gut barrier impairment. Correlation analysis revealed a close relationship among microbiota, SCFAs, and AD-like pathologies. Furthermore, the fecal microbiota of BG-treated rats and SCFAs treatment mitigated AD-like pathologies via the NLRP3 inflammasome pathway in HFD-fed aged rats. These results suggested that long-term BG promotes the production of SCFAs derived from gut microbiota, which further inhibits NLRP3 inflammasome-mediated neuroinflammation, thereby alleviating HFD-induced AD-like pathologies in rats. BG may become a new strategy for targeting neurodegenerative diseases.

The role and mechanism of pyroptosis and potential therapeutic targets in non-alcoholic fatty liver disease (NAFLD).

Non-alcoholic fatty liver disease (NAFLD) is a clinical pathological syndrome characterized by the excessive accumulation of fat within liver cells, which can progress to end-stage liver disease in severe cases, posing a threat to life. Pyroptosis is a distinct, pro-inflammatory form of cell death, differing from traditional apoptosis. In recent years, there has been growing research interest in the association between pyroptosis and NAFLD, encompassing the mechanisms and functions of pyroptosis in the progression of NAFLD, as well as potential therapeutic targets. Controlled pyroptosis can activate immune cells, eliciting host immune responses to shield the body from harm. However, undue activation of pyroptosis may worsen inflammatory responses, induce cellular or tissue damage, disrupt immune responses, and potentially impact liver function. This review elucidates the involvement of pyroptosis and key molecular players, including NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome, gasdermin D (GSDMD), and the caspase family, in the pathogenesis and progression of NAFLD. It emphasizes the promising prospects of targeting pyroptosis as a therapeutic approach for NAFLD and offers valuable insights into future directions in the field of NAFLD treatment.

Antigen-binding fragments with improved crystal lattice packing and enhanced conformational flexibility at the elbow region as crystallization chaperones.

It has been shown previously that a set of three modifications-termed S1, Crystal Kappa, and elbow-act synergistically to improve the crystallizability of an antigen-binding fragment (Fab) framework. Here, we prepared a phage-displayed library and performed crystallization screenings to identify additional substitutions-located near the heavy-chain elbow region-which cooperate with the S1, Crystal Kappa, and elbow modifications to increase expression and improve crystallizability of the Fab framework even further. One substitution (K141Q) supports the signature Crystal Kappa-mediated Fab:Fab crystal lattice packing interaction. Another substitution (E172G) improves the compatibility of the elbow modification with the Fab framework by alleviating some of the strain incurred by the shortened and bulkier elbow linker region. A third substitution (F170W) generates a split-Fab conformation, resulting in a powerful crystal lattice packing interaction comprising the biological interaction interface between the variable heavy and light chain domains. In sum, we have used K141Q, E172G, and F170W substitutions-which complement the S1, Crystal Kappa, and elbow modifications-to generate a set of highly crystallizable Fab frameworks that can be used as chaperones to enable facile elucidation of Fab:antigen complex structures by x-ray crystallography.

Folding and Binding Kinetics of the Tandem of SH2 Domains from SHP2.

The SH2 domains of SHP2 play a crucial role in determining the function of the SHP2 protein. While the folding and binding properties of the isolated NSH2 and CSH2 domains have been extensively studied, there is limited information about the tandem SH2 domains. This study aims to elucidate the folding and binding kinetics of the NSH2-CSH2 tandem domains of SHP2 through rapid kinetic experiments, complementing existing data on the isolated domains. The results indicate that while the domains generally fold and unfold independently, acidic pH conditions induce complex scenarios involving the formation of a misfolded intermediate. Furthermore, a comparison of the binding kinetics of isolated NSH2 and CSH2 domains with the NSH2-CSH2 tandem domains, using peptides that mimic specific portions of Gab2, suggests a dynamic interplay between NSH2 and CSH2 in binding Gab2 that modulate the microscopic association rate constant of the binding reaction. These findings, discussed in the context of previous research on the NSH2 and CSH2 domains, enhance our understanding of the function of the SH2 domain tandem of SHP2.

Detecting genetic gain and loss events in terms of protein domain: Method and implementation.

Continuous gain and loss of genes are the primary driving forces of bacterial evolution and environmental adaptation. Studying bacterial evolution in terms of protein domain, which is the fundamental function and evolutionary unit of proteins, can provide a more comprehensive understanding of bacterial differentiation and phenotypic adaptation processes. Therefore, we proposed a phylogenetic tree-based method for detecting genetic gain and loss events in terms of protein domains. Specifically, the method focuses on a single domain to trace its evolution process or on multiple domains to investigate their co-evolution principles. This novel method was validated using 122 Shigella isolates. We found that the loss of a significant number of domains was likely the main driving force behind the evolution of Shigella, which could reduce energy expenditure and preserve only the most essential functions. Additionally, we observed that simultaneously gained and lost domains were often functionally related, which can facilitate and accelerate phenotypic evolutionary adaptation to the environment. All results obtained using our method agree with those of previous studies, which validates our proposed method.

Astragaloside IV inhibits inflammation caused by influenza virus via reactive oxygen species/NOD-like receptor thermal protein domain associated protein 3/Caspase-1 signaling pathway.

BACKGROUND: Astragaloside IV (AS-IV) is the most active monomer in the traditional Chinese herbal medicine Radix Astragali, which has a wide range of antiviral, anti-inflammatory, and antifibrosis pharmacological effects, and shows protective effects in acute lung injury. METHODS: This study utilized the immunofluorescence, flow cytometry, enzyme-linked immunosorbent assay, quantitative reverse transcription-polymerase chain reaction, western blot, and hematoxylin and eosin staining methods to investigate the mechanism of AS-IV in reducing viral pneumonia caused by influenza A virus in A549 cells and BALB/c mice. RESULTS: The results showed that AS-IV suppressed reactive oxygen species production in influenza virus-infected A549 cells in a dose-dependent manner, and subsequently inhibited the activation of nucleotide-binding oligomerization domain-like receptor thermal protein domain associated protein 3 inflammasome and Caspase-1, decreased interleukin (IL) -1ß and IL-18 secretion. In BALB/c mice infected with Poly (I:C), oral administration of AS-IV can significantly reduce Poly (I:C)-induced acute pneumonia and lung pathological injury. CONCLUSIONS: AS-IV alleviates the inflammatory response induced by influenza virus in vitro and lung flammation and structural damage caused by poly (I:C) in vivo.

Methylmercury induces inflammatory response and autophagy in microglia through the activation of NLRP3 inflammasome.

Methylmercury (MeHg) is a global environmental pollutant with neurotoxicity, which can easily crosses the blood-brain barrier and cause irreversible damage to the human central nervous system (CNS). CNS inflammation and autophagy are known to be involved in the pathology of neurodegenerative diseases. Meanwhile, MeHg has the potential to induce microglia-mediated neuroinflammation as well as autophagy. This study aims to further explore the exact molecular mechanism of MeHg neurotoxicity. We conducted in vitro studies using BV2 microglial cell from the central nervous system of mice. The role of inflammation and autophagy in the damage of BV2 cells induced by MeHg was determined by detecting cell viability, cell morphology and structure, reactive oxygen species (ROS), antioxidant function, inflammatory factors, autophagosomes, inflammation and autophagy-related proteins. We further investigated the relationship between the inflammatory response and autophagy induced by MeHg by inhibiting them separately. The results indicated that MeHg could invade cells, change cell structure, activate NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and autophagosome, release a large amount of inflammatory factors and trigger the inflammatory response and autophagy. It was also found that MeHg could disrupt the antioxidant function of cells. In addition, the inhibition of NLRP3 inflammasome alleviated both cellular inflammation and autophagy, while inhibition of autophagy increased cellular inflammation. Our current research suggests that MeHg might induce BV2 cytotoxicity through inflammatory response and autophagy, which may be mediated by the NLRP3 inflammasome activated by oxidative stress.

Japanese encephalitis virus E protein domain III immunization mediates cross-protection against Zika virus in mice via antibodies and CD8+T cells.

Zika virus (ZIKV) and Japanese encephalitis virus (JEV) are antigenically related flaviviruses that co-circulate in many countries/territories. The interaction between the two viruses needs to be determined. Recent findings by ourselves and other labs showed that JEV-elicited antibodies (Abs) and CD8+T cells exacerbate and protect against subsequent ZIKV infection, respectively. However, the impact of JEV envelope (E) protein domain III (EDIII)-induced immune responses on ZIKV infection is unclear. We show here that sera from JEV-EDIII-vaccinated mice cross-react with ZIKV-EDIII in vitro, and transfer of the same sera to mice significantly decreases death upon lethal ZIKV infection at a dose-dependent manner. Maternally acquired anti-JEV-EDIII Abs also significantly reduce the mortality of neonatal mice born to JEV-EDIII-immune mothers post ZIKV challenge. Similarly, transfer of ZIKV-EDIII-reactive IgG purified from JEV-vaccinated humans increases the survival of ZIKV-infected mice. Notably, transfer of an extremely low volume of JEV-EDIII-immune sera or ZIKV-EDIII-reactive IgG does not mediate the Ab-mediated enhancement (ADE) of ZIKV infection. Similarly, transfer of JEV-EDIII-elicited CD8+T cells protects recipient mice against ZIKV challenge. These results demonstrate that JEV-EDIII-induced immune components including Abs and T cells have protective roles in ZIKV infection, suggesting EDIII is a promising immunogen for developing effective and safety JEV vaccine.

Pellino1 orchestrates gut-kidney axis to perpetuate septic acute kidney injury through activation of STING pathway and NLRP3 inflammasome.

AIMS: Intestinal barrier dysfunction is the initial and propagable factor of sepsis in which acute kidney injury (AKI) has been considered as a common life-threatening complication. Our recent study identifies the regulatory role of Pellino1 in tubular death under inflammatory conditions in vitro. The objective of our current study is to explore the impact of Pellino1 on gut-kidney axis during septic AKI and uncover the molecular mechanism (s) underlying this process. MATERIALS AND METHODS: Immunohistochemistry (IHC) was conducted to evaluate Pellino1 and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels in renal biopsies from critically ill patients with a clinical diagnosis of sepsis. Functional and mechanistic studies were characterized in septic models of the Peli-knockout (Peli1-/-) mice by histopathological staining, enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunofluorescence, biochemical detection, CRISPR/Cas9-mediated gene editing and intestinal organoid. KEY FINDINGS: Pellino1, together with NLRP3, are highly expressed in renal biopsies from critically ill patients diagnosed with sepsis and kidney tissues of septic mice. The Peli1-/- mice with sepsis become less prone to develop AKI and have markedly compromised NLRP3 activation in kidney. Loss of Peli1 endows septic mice refractory to intestinal inflammation, barrier permeability and enterocyte apoptosis that requires stimulator of interferons genes (STING) pathway. Administration of STING agonist DMXAA deteriorates AKI and mortality of septic Peli1-/- mice in the presence of kidney-specific NLRP3 reconstitution. SIGNIFICANCE: Our studies suggest that Pellino1 has a principal role in orchestrating gut homeostasis towards renal pathophysiology, thus providing a potential therapeutic target for septic AKI.

[Mechanism of traditional Chinese medicine in regulating NLRP3 inflammasomes to alleviate renal interstitial fibrosis in diabetic nephropathy: a review].

Diabetic nephropathy(DN), a progressive chronic kidney disease(CKD) induced by diabetes mellitus, is the main cause of end-stage renal disease. Renal interstitial fibrosis(RIF) is an irreversible factor in the progression and deterioration of the renal function in DN. Chronic inflammation has become a key link in the pathogenesis of DN-RIF. The NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome is an important inflammatory regulator regulated by a variety of signals. It promotes the production of pro-inflammatory cytokines and induces renal inflammatory cell infiltration to participate in the process of renal fibrosis, demonstrating a complex mechanism of action. In view of the important role of NLRP3 inflammasomes in the prevention and treatment of DN-RIF, a large number of experimental studies have demonstrated that traditional Chinese medicine(TCM) can reduce the inflammation by regulating the pathways involving NLRP3 inflammasome, thereby slowing down the progression of DN-RIF and improving the renal function. This paper reviews the relationship between NLRP3 inflammasomes and DN-RIF, and the research progress in the mechanism of TCM intervention in NLRP3 inflammasomes to alleviate DN-RIF, aiming to provide new ideas for the targeted treatment of DN-RIF.

The importance of protein domain mutations in cancer therapy.

Cancer is a complex disease that is caused by multiple genetic factors. Researchers have been studying protein domain mutations to understand how they affect the progression and treatment of cancer. These mutations can significantly impact the development and spread of cancer by changing the protein structure, function, and signalling pathways. As a result, there is a growing interest in how these mutations can be used as prognostic indicators for cancer prognosis. Recent studies have shown that protein domain mutations can provide valuable information about the severity of the disease and the patient's response to treatment. They may also be used to predict the response and resistance to targeted therapy in cancer treatment. The clinical implications of protein domain mutations in cancer are significant, and they are regarded as essential biomarkers in oncology. However, additional techniques and approaches are required to characterize changes in protein domains and predict their functional effects. Machine learning and other computational tools offer promising solutions to this challenge, enabling the prediction of the impact of mutations on protein structure and function. Such predictions can aid in the clinical interpretation of genetic information. Furthermore, the development of genome editing tools like CRISPR/Cas9 has made it possible to validate the functional significance of mutants more efficiently and accurately. In conclusion, protein domain mutations hold great promise as prognostic and predictive biomarkers in cancer. Overall, considerable research is still needed to better define genetic and molecular heterogeneity and to resolve the challenges that remain, so that their full potential can be realized.

DEMO-EM2: assembling protein complex structures from cryo-EM maps through intertwined chain and domain fitting.

The breakthrough in cryo-electron microscopy (cryo-EM) technology has led to an increasing number of density maps of biological macromolecules. However, constructing accurate protein complex atomic structures from cryo-EM maps remains a challenge. In this study, we extend our previously developed DEMO-EM to present DEMO-EM2, an automated method for constructing protein complex models from cryo-EM maps through an iterative assembly procedure intertwining chain- and domain-level matching and fitting for predicted chain models. The method was carefully evaluated on 27 cryo-electron tomography (cryo-ET) maps and 16 single-particle EM maps, where DEMO-EM2 models achieved an average TM-score of 0.92, outperforming those of state-of-the-art methods. The results demonstrate an efficient method that enables the rapid and reliable solution of challenging cryo-EM structure modeling problems.

Identification of a conserved α-helical domain at the N terminus of human DNA methyltransferase 1.

In vertebrates, DNA methyltransferase 1 (DNMT1) contributes to preserving DNA methylation patterns, ensuring the stability and heritability of epigenetic marks important for gene expression regulation and the maintenance of cellular identity. Previous structural studies have elucidated the catalytic mechanism of DNMT1 and its specific recognition of hemimethylated DNA. Here, using solution nuclear magnetic resonance spectroscopy and small-angle X-ray scattering, we demonstrate that the N-terminal region of human DNMT1, while flexible, encompasses a conserved globular domain with a novel α-helical bundle-like fold. This work expands our understanding of the structure and dynamics of DNMT1 and provides a structural framework for future functional studies in relation with this new domain.

"Mix and match" auto-assembly of glycosyltransferase domains delivers biocatalysts with improved substrate promiscuity.

Glycosyltransferases (GT) catalyze the glycosylation of bioactive natural products, including peptides and proteins, flavonoids, and sterols, and have been extensively used as biocatalysts to generate glycosides. However, the often narrow substrate specificity of wild-type GTs requires engineering strategies to expand it. The GT-B structural family is constituted by GTs that share a highly conserved tertiary structure in which the sugar donor and acceptor substrates bind in dedicated domains. Here, we have used this selective binding feature to design an engineering process to generate chimeric glycosyltransferases that combine auto-assembled domains from two different GT-B enzymes. Our approach enabled the generation of a stable dimer with broader substrate promiscuity than the parent enzymes that were related to relaxed interactions between domains in the dimeric GT-B. Our findings provide a basis for the development of a novel class of heterodimeric GTs with improved substrate promiscuity for applications in biotechnology and natural product synthesis.

CD301 and LSECtin glycan-binding receptors of innate immune cells serve as prognostic markers and potential predictors of immune response in breast cancer subtypes.

Glycosylation is a prominent posttranslational modification, and alterations in glycosylation are a hallmark of cancer. Glycan-binding receptors, primarily expressed on immune cells, play a central role in glycan recognition and immune response. Here, we used the recombinant C-type glycan-binding receptors CD301, Langerin, SRCL, LSECtin, and DC-SIGNR to recognize their ligands on tissue microarrays (TMA) of a large cohort (n = 1859) of invasive breast cancer of different histopathological types to systematically determine the relevance of altered glycosylation in breast cancer. Staining frequencies of cancer cells were quantified in an unbiased manner by a computer-based algorithm. CD301 showed the highest overall staining frequency (40%), followed by LSECtin (16%), Langerin (4%) and DC-SIGNR (0.5%). By Kaplan-Meier analyses, we identified LSECtin and CD301 as prognostic markers in different breast cancer subtypes. Positivity for LSECtin was associated with inferior disease-free survival in all cases, particularly in estrogen receptor positive (ER+) breast cancer of higher histological grade. In triple negative breast cancer, positivity for CD301 correlated with a worse prognosis. Based on public RNA single-cell sequencing data of human breast cancer infiltrating immune cells, we found CLEC10A (CD301) and CLEC4G (LSECtin) exclusively expressed in distinct subpopulations, particularly in dendritic cells and macrophages, indicating that specific changes in glycosylation may play a significant role in breast cancer immune response and progression.

Mechanism of Buzhong Yiqitang Intervening in Pyroptosis of AIT in NOD.H-2h4 Mice Based on NLRP3/Caspase-1/GSDMD Pathway / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of Buzhong Yiqitang on pyroptosis in autoimmune thyroiditis （AIT） mice based on the NOD-like receptor hot protein domain related protein 3 （NLRP3）/cysteinyl aspartate specific proteinase-1（Caspase-1）/Gasdermin D （GSDMD） pathway. MethodSixty NOD.H-2h4 mice were divided into normal group， model group， low， medium， and high dose groups （4.10， 8.19， 16.38 g·kg-1）of Buzhong Yiqitang， and selenium yeast tablet group （0.26 mg·kg-1）， with 10 mice in each group. Except for the normal group， all other groups were given 0.05% NaI by gavage for eight weeks to establish a model and then received the drug treatment for eight weeks. The serum levels of thyroid peroxidase antibody （TPO-Ab） and thyroglobulin antibody （TgAb） were detected using enzyme-linked immunosorbent assay （ELISA） method. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in mouse thyroid tissue. The immunohistochemical method was used to detect the protein expression of NLRP3， Caspase-1， interleukin-1β （IL-1β）， and interleukin-18 （IL-18）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18. Western blot was used to detect the levels of pyroptosis-related proteins in thyroid tissue. ResultCompared with the normal group， the serum levels of TPO-Ab and TgAb in the model group were significantly increased （P<0.01）. Thyroid follicles either increased in a cubic shape or were damaged and atrophied， with a large number of lymphocytes infiltrating around the follicles. Compared with the model group， the levels of TPO-Ab and TgAb in other groups were significantly reduced （P<0.01）， and the morphology and structure of follicles were improved. The degree of lymphocyte infiltration was reduced. Among them， the medium dose group of Buzhong Yiqitang had the most significant reduction and improvement effect. Compared with the normal group， the positive products and mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18 proteins in the thyroid tissue of the model group significantly increased （P<0.01）， and the protein expression levels of NLRP3， cleaved Caspase-1， IL-1β， IL-18， and GSDMD-N were significantly increased （P<0.05， P<0.01）. Compared with the model group， the positive products and mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18 proteins in other groups were significantly reduced （P<0.05， P<0.01）， with the most significant reduction effect in the medium dose group of Buzhong Yiqitang. The protein expression levels of NLRP3， cleaved Caspase-1， IL-1β， IL-18， and GSDMD-N were significantly reduced （P<0.05， P<0.01）. ConclusionBuzhong Yiqitang can improve AIT， and its mechanism may be achieved by regulating the NLRP3/Caspase-1/GSDMD signaling pathway to inhibit pyroptosis.

Role of NLRP3 inflammasome in therapeutic mild hypothermia post-treated myocardial ischemia-reperfusion rats / 临床麻醉学杂志

Objective To analyze the role of NOD-like receptor thermal protein domain associated protein 3(NLRP3)inflammasome in a therapeutic mild hypothermia(34℃)treated isolated rat myocardial ischemia-reperfusion model and explore its mechanism.Methods Sixty clean grade adult male SD rats,aged 7-10 weeks,weighing 250-300 g.Using a random number table method,the rats were divid-ed into five groups:blank control group(group S),myocardial ischemia-reperfusion group(group IR),34℃mild hypothermia post-treated myocardial ischemia-reperfusion group(group MH),34℃mild hypother-mia post-treated myocardial ischemia-reperfusion+3-TYP group(group HT),and 34℃mild hypothermia post-treated myocardial ischemia-reperfusion+3-TYP+MCC950 group(group HTM),12 rats in each group.Group S perfused the rat heart at 37℃with a balanced perfusion solution for 180 minutes.Group IR re-ceived balanced perfusion of the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 37℃perfusion for 120 minutes.Group MH perfused the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 34℃perfusion solution for 120 minutes.Group HT perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,silent mating type information regulation 2 homolog 3(sirt3)inhibitor 3-TYP was added to the perfusate,and then per-fused at 34℃for 120 minutes.Group HTM perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,sirt3 inhibitor 3-TYP and NLRP3 inhibitor MCC950 were added to the perfusate,and then perfused at 34℃for 120 minutes.The isolated heart was obtained 120 minutes after reperfusion,and the concentrations of IL-6 and IL-1β in the perfused cardiac fluid was measured using ELISA method,Western blot method for detecting the relative content of NLRP3 and sirt3 proteins in myocardial tissue,1%triphenyl tetrazolium chloride staining for calculating myocardial infarction area,and HE staining for observ-ing myocardial pathological changes.Results Compared with group S,HR were significantly slowed down,LVSP,±dp/dtmax were significantly decreased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,and the per-centage of myocardial infarction area were significantly increased in groups IR,MH,HT,and HTM(P＜0.05),the content of sirt3 protein in myocardial tissue were significantly reduced,while the content of NLRP3 protein were significantly increased in groups IR,HT,and HTM(P＜0.05),the contents of sirt3 and NLRP3 protein in the myocardial tissue were significantly increased in group MH(P＜0.05).Com-pared with group IR,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage and the percentage of myocardial infarction area were significantly decreased in groups MH and HTM(P＜0.05),the content of sirt3 protein in myocardial tissue was signifi-cantly increased,while the content of NLRP3 protein was significantly decreased in group MH(P＜0.05),the content of NLRP3 protein in myocardial tissue was significantly reduced in group HTM(P＜0.05).Compared with group MH,HR were significantly slowed down,LVSP,±dp/dtmax were significantly de-creased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the con-centrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly increased in group HT(P＜0.05),the content of sirt3 protein in myocardial tissue was significantly reduced in groups HT and HTM(P＜0.05).Compared with group HT,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly reduced in group HTM(P＜0.05).Conclusion Therapeutic mild hypothermia(34℃)can improve hemodynamic parameters of isolated hearts and reduce the concentrations of IL-6 and IL-1β,NLRP3 protein content in myocardial tissue,percentage of myocardial infarction area,improve myocardial pathological changes,and reduce myocardial ischemia-reperfusion injury in rats,the mechanism may be related to the mitochondrial mediated sirt3 pathway inhibiting the high expres-sion of inflammatory corpuscle NLRP3.

Specific inhibition of NLRP3 expression in GABAergic neurons in CA1 area of the hippocampus improves cognitive dysfunction in mice after traumatic brain injury / 中华神经医学杂志

Objective:To explore the effect of NOD-like receptor thermal protein 3 ( NLRP3) knockout in γ-aminobutyric acid (GABA)-ergic neurons in the hippocampal CA1 area on improving cognitive dysfunction in mice after traumatic brain injury (TBI). Methods:Forty-eight healthy male NLRP3 flox/flox mice weighing 25-28 g were randomly divided into 4 groups ( n=12): sham-operated+control virus group (SV group), sham-operated+ NLRP3 specific knockout group (SG group), TBI+control virus group (TV group), TBI+ NLRP3 specific knockout group (TG group). TBI in the TV and TG groups was established by free-fall method, while surgical procedures such as scalp incision and cranial window opening without impact were given to the SV and SG groups. Adenovirus was injected into the hippocampal CA1 area of SG and TG groups 21 d before TBI to induce NLRP3 specific knockout in GABA-ergic neurons in the hippocampal CA1 area; empty virus was injected into the CA1 area of SV and TV groups. Cognitive function was evaluated using novel object recognition test 30 and 31 d after TBI, and learning and memory functions were assessed using Morris water maze test 32-36 d after TBI. Field potentials in the hippocampal CA1 area were recorded during novel object recognition 31 d after TBI. After behavioral tests, these mice were sacrificed. Immunofluorescent staining was used to detect the fluorescent intensity of microtubule-associated protein2 (MAP2), glutamic acid decarboxylase 67 (GAD67), and postsynaptic density protein 95 (PSD95) in the hippocampal CA1 area, as well as percentage of pyroptosis-associated inflammatory factor interleukin-18 (IL-18)/GAD67 double-positive neurons in total GAD67 positive neurons. Results:Compared with the SV and SG groups, the TV and TG groups had decreased novel object recognition index, decreased number of platform crossings during the experimental period, increased escape latency on day 3 and day 4 of the training period in Morris water maze test, decreased θ and γ oscillation power in the hippocampal CA1 area during novel object recognition, decreased fluorescent intensity of MAP2, GAD67, and PSD95 in the hippocampal CA1 area, increased percentage of IL-18/GAD67 double-positive neurons, with significant differences ( P<0.05). Compared with the TV group, the TG group had increased novel object recognition index, increased number of platform crossings in Morris water maze test, decreased escape latency during the training period, increased θ and γ oscillation power in the hippocampal CA1 area during novel object recognition, increased fluorescence intensity of MAP2, GAD67, and PSD95 in the hippocampal CA1 area, decreased percentage of IL-18/GAD67 double-positive neurons, with significant differences ( P<0.05). Conclusion:Specific inhibition of NLRP3 expression in GABA-ergic neurons in the hippocampal CA1 area can improve cognitive dysfunction in mice after TBI, whose mechanism may be related to inhibited GABA-ergic neuronal pyroptosis in the hippocampal CA1 area.

Scutellariae Radix-Coptidis Rhizoma Treats Atherosclerosis via NLRP3 Inflammasome-mediated Pyroptosis of Macrophages / 中国实验方剂学杂志

ObjectiveTo investigate the therapeutic effect of Scutellariae Radix-Coptidis Rhizoma （SRCR） on atherosclerosis （AS） in mice and the effect of SRCR on macrophage pyroptosis in plaques via NOD-like receptor thermal protein domain-associated protein 3 （NLRP3） inflammasomes. MethodApoE-/- mice were fed with a high-fat diet for the modeling of AS and randomized into model， atorvastatin （5 mg·kg-1）， and low-， medium-， and high-dose （1.95， 3.9， 7.8 g·kg-1， respectively） SRCR groups. Normal C57BL/6J mice were selected as the control group. After 8 weeks of administration， hematoxylin-eosin staining was used to observe the pathological status of the aortic plaque. The lipid accumulation in aortic plaque was observed by oil red O staining. The serum levels of total cholesterol （TC）， triglyceride （TG）， high-density lipoprotein cholesterol （HDL-C）， and low-density lipoprotein cholesterol （LDL-C） in mice were measured. Immunofluorescence double staining was employed to detect the co-localized expression of EGF-like module-containing mucin-like hormone receptor-like 1 （EMR1）/NLRP3 and EMR1/gasdermin D （GSDMD）. The serum levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） were determined by enzyme-linked immunosorbent assay （ELISA）. The protein levels of NLRP3， apoptosis-associated speck-like protein （ASC）， Caspase-1， cleaved Caspase-1， GSDMD， N-terminus of GSDMD （GSDMD-NT）， pro-IL-1β， IL-1β， and IL-18 were determined by Western blot， and the mRNA levels of NLRP3， ASC， Caspase-1， GSDMD， IL-1β， and IL-18 were determined by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultCompared with the control group， the model group showed obvious plaques， elevated serum levels of TG， TC， LDL-C， IL-1β， and IL-18 （P<0.01）， lowered serum level of HDL-C （P<0.01）， and up-regulated expression of NLRP3 inflammasomes and molecules related to pyroptosis in the aortic plaques （P<0.01）. Compared with the model group， SRCR， especially at the medium and high doses， alleviated the plaque pathology， reduced the lipid content in plaques （P<0.05， P<0.01）， recovered the serum lipid levels （P<0.05）， reduced the macrophage recruitment （P<0.01）， activation of NLRP3 inflammasomes， and pyroptosis in aortic root plaques （P<0.05）， lowered the serum IL-1β and IL-18 levels （P<0.01）， and down-regulated the protein levels of NLRP3， ASC， Caspase-1， cleaved Caspase-1， GSDMD， GSDMD-NT， pro-IL-1β， IL-1β， and IL-18 （P<0.05） and the mRNA levels of NLRP3， ASC， Caspase-1， GSDMD， IL-1β， and IL-18 in the aortic tissue （P<0.05）. ConclusionSRCR exerts a therapeutic effect on high-fat diet-induced AS in mice by inhibiting the activation NLRP3 inflammasomes and reducing the pyroptosis of macrophages in plaques.