Cell Membrane Rupture Research Articles

Nanocluster-mediated photothermia improves eradication efficiency and antibiotic sensitivity of Helicobacter pylori

BackgroundHelicobacter pylori (H. pylori) eradication plays a crucial role in gastric cancer prevention, but the antimicrobial resistance of H. pylori is obstructing this elimination process. In this study, we developed nanoclusters (NCs) from Zn0.3Fe2.7O4 nanoparticles using a poly(ethylene glycol)-b-poly(ε-caprolactone)-based nanocarrier as an innovative antibiotic-independent H. pylori management.ResultsThe nanocluster showed minimal toxicity and maximal biocompatibility. With a low concentration (50 µg/mL) of NCs under a short time period (~ 2 min) of near-infrared (808 nm) irradiation, we kept the culture medium temperature to 41 °C for 20 min with continuous irradiation. The heated NCs exhibited efficient photothermal effects and resulted in an excellent inhibition of H. pylori growth, adhesion and ability to induce vacuolization in eukaryotic cells in in vitro investigation. Transmission electron microscopy showed a dramatic morphologic change after NCs photothermia on H. pylori, including cell wall and membrane rupture, as well as ribosome damage. Besides, levofloxacin and clarithromycin resistance was decreased after photothermal treatment in H. pylori NCTC 11637 and/or clinical strains, however metronidazole resistance was unchanged. We also discovered a significant decrease in the biofilm formation of H. pylori under the NCs-based photothermal application, while efflux pump function was unchanged.ConclusionsBased on this novel NCs-based photothermal approach, we were able to demonstrate in vitro a significant inhibition of both H. pylori growth and molecular toxicity, and its improvement in antibiotic sensitivity alone with the eradication of H. pylori biofilms previously believed to be tolerant to conventional antibiotics.

A case of rhabdomyolysis with rigors

Introduction: Rhabdomyolysis is a potential life-threatening condition caused by extensive skeletal muscle breakdown with leakage of toxic muscle contents into the circulation. The most dreaded complication is acute renal failure caused by toxic effects of myoglobin in the kidneys. The causes of rhabdomyolysis are classified into traumatic, non-traumatic exertional, and non-traumatic rhabdomyolysis. The pathophysiologic hallmark of rhabdomyolysis regardless of etiology is increased free ionized calcium due to cellular energy depletion (ATP) or direct plasma membrane rupture and consequent intensified muscle contractility, mitochondrial dysfunction, and production of oxygen radicals. Case Report: We report a case of a middle-aged black woman with rhabdomyolysis that was caused by intense shivering chills, and rigor from pneumonitis. She had no personal or family history of muscle disorder and was admitted to the hospital after a weeklong history of upper and lower respiratory symptoms that led to the worse shivering and shaking chills she ever had. She was noted to have elevated creatine phosphokinase (CPK) of 200,000 uL (26–192 uL) and creatinine level of 5.52 (0.81–1.2 mg/dL). She was started on intravenous fluid with half-isotonic saline (0.45%) or 77 mmol/L sodium, 75 mmol/L sodium bicarbonate, and hemodialysis with progressive improvement in kidney function that took up to seven weeks to full recovery. Conclusion: Shivering and shaking chills from respiratory infection can cause rhabdomyolysis with severe muscle damage and renal failure in a patient with no known underlying muscular-skeletal disorder condition but has good recovery with fluid management and hemodialysis. Renal function has returned back to normal.

Exposure to nanoplastic induces cell damage and nitrogen inhibition of activated sludge: Evidence from bacterial individuals and groups

Wastewater treatment plants (WWTPs) are almost the only place where plastic fragments are artificially removed, resulting in mass accumulation of nanoplastics (NPs). In this research, four different concentrations (0 mg/L, 0.1 mg/L, 1 mg/L, 10 mg/L) of polystyrene nanoplastics (PS-NPs) were used to investigate the cell damage and nitrogen inhibition of activated sludge, exposed in a self-assembled SBR reactor for 30 days. Intracellular reactive oxides (ROS) and extracellular lactate dehydrogenase (LDH) increased with the rise of exposure concentration, and morphological analysis disclosed the creases, collapse, and even rupture of cell membranes. However, exposure damage (PS-NPs ≤ 1 mg/L) appeared to be reversible, attributed to that extracellular polymeric substances (EPS) secretion can thicken the three protective layers outside the membrane. PS-NPs did not disrupt the EPS chemical structure, but increased humic acid content. Prolonged exposure time (from 15 to 30 days) was directly related to the nitrogen inhibition. Due to the habitat changes under PS-NPs exposure, abundance and diversity of microorganisms in the original activated sludge decreased significantly, and the dominant phylum was occupied by Patescibacteria (PS-NPs = 10 mg/L). Changes in enzyme activities of AMO, NR, NIR, and NOR with exposure concentration may explain the conversion of nitrogen in SBR. This research broadens our horizons to understand the response mechanism of activated sludge bacteria to PS-NPs exposure individually and collectively.

Yinchenhao Decoction ameliorates the high-carbohydrate diet induced suppression of immune response in largemouth bass (Micropterus salmoides)

Yinchenhao Decoction (YD), a Chinese herbal medicine, has been traditionally used for treatment of metabolic liver diseases. A 10-week feeding trail was carried out to examine the effects of YD supplementation in a high carbohydrate diet (HCD) on liver histopathology, immune response, disease resistance, and expression of genes associated with endoplasmic reticulum stress, autophagy, apoptosis, necroptosis and inflammation in juvenile largemouth. A diet containing 9% carbohydrate was used as a low carbohydrate diet (LCD), and a HCD was formulated to contain 18% carbohydrate and supplemented with 0, 0.5, 1, 2 or 4% YD (HCD, HCD+0.5YD, HCD+1YD, HCD+2YD and HCD+4YD). Triplicate groups of fish (5.6 ± 0.2 g) were feed the test diets to visual satiety for 10 weeks. The highest survival rate after Nocardia seriolae challenge was recorded for the HCD+4YD group. YD application led to reduced ACP, AKP, AST and ALT activities. HCD-induced cells swelling, ruptured cell membrane, migrated nuclei and increasing inflammatory cells in hepatocytes were mitigated by YD addition. Moreover, YD decreased the expressions of pro-inflammation genes (TNF-α, IL-1β, IL-8, hepcidin1, NF-κB, COX2, CD80 and CD83) and increased the mRNA levels of anti-inflammation genes (IL-10 and IKBα). The mode of liver cell death was preferably changed to programed apoptosis rather than uncontrolled necroptosis by application of YD in HCD. Furthermore, the expression of UPR genes (IRE1, Eif2α, ATF6, XBP1 and GRP78/Bip) and autophagy genes (LC3-2, BNIP3 and P62) was increased by YD supplementation. In summary, our results demonstrated that YD addition in HCD enhances UPR, autophagy and programed apoptosis maintaining the homeostasis, and decreases uncontrolled necroptosis and inflammation, ultimately leading to improved immune response in largemouth bass.

Identification of a Pyroptosis-Related Gene Signature for Predicting the Immune Status and Prognosis in Lung Adenocarcinoma.

Background: Pyroptosis is a form of programmed cell death triggered by the rupture of cell membranes and the release of inflammatory substances; it is essential in the occurrence and development of cancer. A considerable number of studies have revealed that pyroptosis is closely associated to the biological process of several cancers. However, the role of pyroptosis in lung adenocarcinoma (LUAD) remains elusive. The purpose of this study was to explore the prognostic role of pyroptosis-related genes (PRGs) and their relationship with the tumor immune microenvironment (TIME) in LUAD. Methods: Gene expression profiles and clinical information were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A prognostic PRG signature was established in the training set and verified in the validation sets. Functional enrichment and immune microenvironment analyses related to PRGs were performed and a nomogram based on the risk score and clinical characteristics was established. What is more, quantitative real-time PCR (qRT-PCR) analysis was applied in order to verify the potential biomarkers for LUAD. Results: A prognostic signature based on five PRGs was constructed to separate LUAD patients into two risk groups. Patients in the high-risk group had worse prognoses than those in the low-risk group. The signature was identified as independent via Cox regression analyses and obtained the largest area under the curve (AUC = 0.677) in the receiver operating characteristic (ROC). Functional enrichment and immune microenvironment analyses demonstrated that the immune status was significantly different in the two subgroups and that immunotherapy may be effective for the high-risk group. Furthermore, qRT-PCR analysis verified that serum PRKACA and GPX4 could serve as diagnostic biomarkers for LUAD. Conclusion: Overall, a risk signature based on five PRGs was generated, providing a novel perspective on the determinants of prognosis and survival in LUAD, as well as a basis for the development of individualized regimes.

Granzyme F production by CD8 T cells in the tumor microenvironment

Abstract Granzymes are a class of cytotoxic proteases and are the primary mechanism utilized by T cells to directly eliminate cancer cells. Each granzyme acts upon a unique set of substrates in target cells to induce cytotoxicity through a range of different mechanisms. Granzymes are some of the most differentially regulated genes in CD8+ tumor infiltrating lymphocytes, relative to T cells outside of the tumor microenvironment (TME). We and others have determined by microarray and qPCR that granzyme F is highly upregulated in the TME. Granzyme F expression is restricted to a small subset of antigen-experienced and exhausted T cells, as determined by flow cytometry-based detection of granzyme F RNA transcripts and may represent a marker of a unique T cell cytotoxic function. Single cell RNA sequencing of CD8 TIL has revealed that granzyme F-high expressing cells are unique from both granzyme A and B expressing cells, and that it is therefore likely these TIL utilize a unique mechanism of cytotoxicity in their elimination of cancer cells. Recombinant granzyme F has previously been shown to induce a unique form of cell death, characterized as being caspase-independent and resulting in rupture of target cell plasma membrane. By over expressing granzyme F we are determining if this mechanism of cell death is leverageable to improve the cytotoxic capacity of TIL, and if induction of different forms of T cell-mediated cytotoxicity can modulate the immunogenicity of the TME. These experiments are designed to provide insight into how to improve adoptive T cell therapies by directly improving cytotoxicity, the terminal step of T cell interaction with tumor cells. This work was supported by the National Institutes of Health NIAID training grant (Training Program in Immunology; T32-AI07405) award to Zachary Hay

An all-in-one CO gas therapy-based hydrogel dressing with sustained insulin release, anti-oxidative stress, antibacterial, and anti-inflammatory capabilities for infected diabetic wounds

To effectively treat diabetic wounds, the development of versatile medical dressings that can long-term regulate blood glucose and highly effective anti-oxidative stress, antibacterial and anti-inflammatory are critical. Here, an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) was developed via the dynamic Schiff base reaction between the amino groups on quaternized chitosan (QCS) and the aldehyde groups on benzaldehyde-terminated F108 (F108-CHO) micelles. CORM-401 (an oxidant-sensitive CO-releasing molecules) was encapsulated in the hydrophobic core of F108-CHO micelles and insulin was loaded in the three-dimensional network structure of ICOQF. The dynamic Schiff base bonds not only endowed ICOQF with good tissue adhesion, injectability and self-healing, but also gave it sustained and controllable insulin release ability. In addition, ICOQF could quickly generate CO in inflamed wound tissue by consuming reactive oxygen species. The generated CO could effectively anti-oxidative stress by activating the expression of heme oxygenase; antibacterial by inducing the rupture of bacterial cell membranes and mitochondrial dysfunction and inhibiting the synthesis of adenosine triphosphate; and anti-inflammatory by inhibiting the proliferation of activated macrophages and promoting the polarization of the M1 phenotype to the M2 phenotype. Due to these outstanding properties, ICOQF significantly promoted the healing of STZ-induced MRSA-infected diabetic wounds accompanied by good biocompatibility. This study clearly shows that ICOQF is a versatile hydrogel dressing with great application potential for the management of diabetic wounds. Statement of significanceThe development of some versatile hydrogel dressings that can not only provide a prolonged and controlled insulin release property but also utilize a non-antibiotic treatment modality for highly effective antibacterial, anti-inflammatory, and anti-oxidative stress effects is vital for the successful treatment of diabetic wounds. Herein, we developed an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) with sustained and controllable insulin release abilities. Moreover, ICOQF could not only quickly release CO in the inflamed wound tissue by consumption of reactive oxygen species but also utilize the generated CO to highly effectively anti-oxidative stress, antibacterial, and anti-inflammatory. ICOQF therapy substantially promoted the healing of STZ-induced MRSA-infected diabetic wounds. Overall, this work provides a multifunctional hydrogel dressing for the management of diabetic wounds.

Size- and shape-dependent cytotoxicity of nano-sized Zr-based porphyrinic metal-organic frameworks to macrophages

The wide utilization of nano-sized metal-organic frameworks (NMOFs) leads to inevitable health risks to humans. Previous studies on health risks of NMOFs mainly focus on the cytotoxic tests of typical NMOFs，but lack sufficient studies on the effects of physiochemical characteristics of NMOFs on the cytotoxicity and the related mechanisms. Here, four kinds of Zr-based porphyrinic NMOFs (PCNs), including spherical 30, 90, and 180 nm PCN-224 and rod-like 90 nm PCN-222, were taken as a proof of the concept to investigate the effects of the size and shape of NMOFs on the cytotoxicity and related mechanisms to macrophages. The 30 nm spherical PCN-224 induced significant rupture of cell membrane and dissolved in lysosome, leading to the most significant cell necrosis among the studied other nano-sized PCNs. However, other studied PCNs showed insignificant membrane rupture and their dissolution in lysosome. Furthermore, the 90 nm-sized PCN-224 led to much more significant cell necrosis by inducing lysosome damage and inhibiting of autophagy flux than the rod-like 90 nm PCN-222. These findings reveal the size- and shape-dependent cytotoxicity of PCNs and the related mechanisms and are helpful to the assessment of the potential health risks of NMOFs and the safe application of NMOFs.

BAK plays a key role in A-1331852-induced apoptosis in senescent chondrocytes

Osteoarthritis occurs when the number of senescent chondrocytes in the joints reaches an intolerable level. The purpose of our study was to explore the therapeutic effect and mechanism of action of A-1331852 in osteoarthritis. Doxorubicin and etoposide were used to induce cell senescence as determined by the cessation of cell proliferation, augmented senescence-associated beta-galactosidase (SA-β-Gal) staining, and increased p53 expression levels. The CCK-8 cytotoxicity assay and SA-β-Gal staining demonstrated that Bcl-xL inhibitors could selectively remove senescent chondrocytes without damaging healthy chondrocytes. A-1331852 induced caspase-dependent death of senescent chondrocytes with decreased mitochondrial membrane potential, nuclear concentration, plasma membrane rupture, and PARP cleavage. Most importantly, A-1331852 upregulated BAK expression levels, indicating that BAK plays a key role in the A-1331852-induced apoptosis of senescent chondrocytes. Live-cell fluorescence resonance energy transfer showed that A-1331852 detached the binding of Bcl-xL to BAK and promoted the oligomerization of BAK on the mitochondrial membrane. In conclusion, this study provides the first evidence that A-1331852 selectively promotes apoptosis in senescent chondrocytes by interfering with the interaction between Bcl-xL and BAK.

A transistor-like pH-sensitive nanodetergent for selective cancer therapy.

Plasma membrane rupture is a promising strategy for drug-resistant cancer treatment, but its application is limited by the low tumour selectivity of membranolytic molecules. Here we report the design of 'proton transistor' nanodetergents that can convert the subtle pH perturbation signals of tumour tissues into sharp transition signals of membranolytic activity for selective cancer therapy. Our top-performing 'proton transistor' nanodetergent, P(C6-Bn20), can achieve a >32-fold change in cytotoxicity with a 0.1 pH input signal. At physiological pH, P(C6-Bn20) self-assembles into neutral nanoparticles with inactive membranolytic blocks shielded by poly(ethylene glycol) shells, exhibiting low toxicity. At tumour acidity, a sharp transition in its protonation state induces a morphological transformation and an activation of the membranolytic blocks, and the cation-π interaction facilitates the insertion of benzyl groups-containing hydrophobic domains into the cell membranes, resulting in potent membranolytic activity. P(C6-Bn20) is well tolerated in mice and shows high anti-tumour efficacy in various mouse tumour models.

Antibacterial effect and mechanism against Escherichia coli of polysaccharides from Armillariella tabescens mycelia

The objectives of this study were (1) to prepare Armillariella tabescens mycelia polysaccharides (PAT) with remarkably growth inhibitory effect on typical food-borne pathogenic bacteria using a green and efficient polyamide method and (2) to explore the antibacterial mechanism of PAT for use as a natural antibacterial agent. The sugar and uronic acid contents of PAT were 93.41% and 12.24%, respectively. PAT could inhibit the growth of Escherichia coli, Proteus vulgaris, Bacillus subtilis, and Staphylococcus aureus cells, with minimum inhibitory concentrations of 0.5, 1.0, 4.0, and 4.0 mg/mL, respectively. Ultra-high-resolution field emission scanning electron microscopy and high-resolution transmission electron microscopy analysis revealed cell wall and membrane rupture of E. coli treated with PAT. Further, 0.5–4.0 mg/mL PAT was found to significantly (P < 0.01) and concentration-dependently increase the conductivity of the broth, exudation of the intracellular protein, and alkaline phosphatase and β-galactosidase activities. Confocal laser scanning microscopy revealed morphological changes in E. coli DNA after PAT treatment and intracellular reactive oxygen species accumulation; flow cytometry revealed E. coli cell apoptosis. Our findings provide a theoretical basis and technical support for the development of PAT as a natural antibacterial product.

Porcine Gasdermin D Is a Substrate of Caspase-1 and an Executioner of Pyroptosis.

Gasdermin (GSDM) family proteins were recently identified as the executioner of pyroptosis. The mechanism of pyroptosis mediated by gasdermin D (GSDMD) (a member of GSDM family) in humans and mice is well understood. In pyroptosis, mouse and human GSDMDs are cleaved by activated proinflammatory caspases (caspase-1, 4, 5, or 11) to produce anamino-terminal domain (GSDMD-NT) and a carboxyl-terminal domain (GSDMD-CT). The GSDMD-NT drives cell membrane rupture, which leads to the pyroptotic death of the cells. The expression of porcine GSDMD (pGSDMD) has recently been determined, but the activation and regulation mechanism of pGSDMD and its ability to mediate pyroptosis are largely unknown. In the present study, the activation of porcine caspase-1 (pcaspase-1) and cleavage of pGSDMD occurred in the duodenum and jejunum of a piglet challenged with enterotoxigenic Escherichia coli were first determined. Then the capability of pcaspase-1 to cleave pGSDMD was determined in a cell-free system and in human embryonic kidney cells. The pGSDMD cleavage by pcaspase-1 occurred after the pGSDMD molecule’s 276Phenylalanine-Glutamine-Serine-Aspartic acid279 motif. The pGSDMD-NT generated from the pGSDMD cleavage by pcaspase-1 showed the ability to drive cell membrane rupture in eukaryotic cells. When expressed in E. coli competent cells, pGSDMD-NT showed bactericidal activity. These results suggest that pGSDMD is a substate of pcaspase-1 and an executioner of pyroptosis. Our work sheds light on pGSDMD’s activation mechanisms and functions.

Curcumin-Mediated Sono-Photodynamic Treatment Inactivates Listeria monocytogenes via ROS-Induced Physical Disruption and Oxidative Damage.

Sono-photodynamic sterilization technology (SPDT) has become a promising non-thermal food sterilization technique because of its high penetrating power and outstanding microbicidal effects. In this study, Listeria monocytogenes (LMO) was effectively inactivated using curcumin as the sono-photosensitizer activated by ultrasound and blue LED light. The SPDT treatment at optimized conditions yielded a 4-log reduction in LMO CFU. The reactive oxygen species (ROS) production in LMO upon SPDT treatment was subsequently investigated. The results demonstrated SPDT treatment-induced excessive ROS generation led to bacterial cell deformation and membrane rupture, as revealed by the scanning electron microscope (SEM) and cytoplasmic material leakage. Moreover, agarose gel electrophoresis and SDS-PAGE further revealed that SPDT also triggered bacterial genomic DNA cleavage and protein degradation in LMO, thus inducing bacterial apoptosis-like events, such as membrane depolarization.

The lipid peroxidation product 4-hydroxynonenal inhibits NLRP3 inflammasome activation and macrophage pyroptosis.

Pyroptosis is a form of cell death triggered by the innate immune system that has been implicated in the pathogenesis of sepsis and acute lung injury. At the cellular level, pyroptosis is characterized by cell swelling, membrane rupture, and release of inflammatory cytokines, such as IL-1β. However, the role of endogenous lipids in pyroptosis remains underappreciated. We discovered that 4-hydroxynonenal (HNE), a major endogenous product of lipid peroxidation, inhibited pyroptosis and inflammasome activation. HNE at physiological concentrations (3 µM) blocked nigericin and ATP-induced cell death, as well as secretion of IL-1β, by mouse primary macrophages and human peripheral blood mononuclear cells. Treatment with HNE, or an increase of endogenous HNE by inhibiting glutathione peroxidase 4, reduced inflammasome activation in mouse models of acute lung injury and sepsis. Mechanistically, HNE inhibited the NLRP3 inflammasome activation independently of Nrf2 and NF-κB signaling, and had no effect on the NLRC4 or AIM2 inflammasome. Furthermore, HNE directly bound to NLRP3 and inhibited its interaction with NEK7. Our findings identify HNE as a novel, endogenous inhibitor of the NLRP3 inflammasome.

Antifreeze Proteins: Novel Applications and Navigation towards Their Clinical Application in Cryobanking.

Antifreeze proteins (AFPs) or thermal hysteresis (TH) proteins are biomolecular gifts of nature to sustain life in extremely cold environments. This family of peptides, glycopeptides and proteins produced by diverse organisms including bacteria, yeast, insects and fish act by non-colligatively depressing the freezing temperature of the water below its melting point in a process termed thermal hysteresis which is then responsible for ice crystal equilibrium and inhibition of ice recrystallisation; the major cause of cell dehydration, membrane rupture and subsequent cryodamage. Scientists on the other hand have been exploring various substances as cryoprotectants. Some of the cryoprotectants in use include trehalose, dimethyl sulfoxide (DMSO), ethylene glycol (EG), sucrose, propylene glycol (PG) and glycerol but their extensive application is limited mostly by toxicity, thus fueling the quest for better cryoprotectants. Hence, extracting or synthesizing antifreeze protein and testing their cryoprotective activity has become a popular topic among researchers. Research concerning AFPs encompasses lots of effort ranging from understanding their sources and mechanism of action, extraction and purification/synthesis to structural elucidation with the aim of achieving better outcomes in cryopreservation. This review explores the potential clinical application of AFPs in the cryopreservation of different cells, tissues and organs. Here, we discuss novel approaches, identify research gaps and propose future research directions in the application of AFPs based on recent studies with the aim of achieving successful clinical and commercial use of AFPs in the future.

Acupoint catgut embedment may reduce airway inflammation reaction by down-regulating ICAM-1 and EOS by suppressing p38MAPK signaling in lung tissue of asthmatic rats

To observe the effect of acupoint catgut embedment(ACE) on expression of p38 mitogen activated protein kinase (p38MAPK), intercellular adhesion molecule-1(ICAM-1), interleukin-4 (IL-4) and eosinophils (EOS) in lung tissue of asthmatic rats, so as to explore its mechanism underlying improvement of asthma. Forty male Wistar rats were randomly divided into control, model, ACE and dexamethasone (DEX) groups, with 10 rats in each group. The asthmatic model was established by intraperitoneal injection of mixture suspension (1 mL) of ovalbumin (OVA,10%) and 10% Al (OH)3+ normal saline, followed by inhalation of atomized 1% OVA solution for 30 min, once daily for 2 weeks to trigger occurrence of asthmatic symptoms. The ACE was applied once to "Feishu" (BL13), "Dingchuan" (EX-B1) and "Danzhong" (CV17). Rats of the DEX group were given intraperitoneal injection of DEX once a day for 2 weeks. H.E. staining was used to evaluate histopathological changes of the lung tissue. The relative number of EOS in the bronchoalveolar lavage fluid (BALF) was detected by Wright Giemsa staining. The apoptosis level of EOS in the lung tissue was detected by TUNEL staining. The ultrastructural changes of EOS in the lung tissues were observed by transmission electron microscope (TEM). The expression of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue was detected by quantitative real-time PCR. Findings of optical microscope and TEM showed obvious bronchial deformation and inflammatory cell infiltration, rupture of EOS cell membrane, uneven cytoplasm with swelling and uneven density of eosinophilic granules in EOS of the model group, which was relatively milder in the ACE and DEX groups. Compared with the control group, the EOS number in BALF and the expressions of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue were significantly increased (P<0.01), and the apoptosis index of EOS in the lung tissue was significantly decreased (P<0.01) in the model group. After intervention, the EOS number in BALF and expression levels of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue of ACE and DEX groups were significantly decreased (P<0.01, P<0.05), as well as the apoptosis index of EOS in the lung tissue was significantly increased in both ACE and DEX groups (P<0.01) in comparison with the model group. The EOS number in BALF and expression of ICAM-1 mRNA were significantly lower in the DEX group than those in the ACE group (P<0.05). Catgut embedding at acupoints may alleviate the airway inflammatory response in asthma rats, which may be related with its effects in down-regulating p38MAPK signaling, ICAM-1 and IL-4 mRNA expression, reducing the aggregation of EOS, and promoting the apoptosis of EOS.

Protective role of curcumin on aflatoxin B1-induced TLR4/RIPK pathway mediated-necroptosis and inflammation in chicken liver

This study set out to assess the mitigative effects of curcumin on AFB1-induced necroptosis and inflammation in chicken liver. Ninety-six one-day-old AA broiler chickens were separated into four groups, including control group, AFB1 (1 mg/kg) group, curcumin (300 mg/kg) + AFB1 (1 mg/kg) group and curcumin (300 mg/kg) group. After 28 days treatment, livers were collected for different experimental analyses. The morphological observation results showed obvious necrotic characteristics, including cell swelling, rupture of cell and mitochondrial membranes and inflammation in chicken livers. AFB1 exposure increased oxidative stress index (ROS and MDA) and decreased the antioxidant activity markers (SOD, CAT and GSH) and ATPase activities in chickens’ liver. ELISA results showed that AFB1 exposure significantly induced the cytokines (TNF-α, iNOS, IL-6 and IL-1β) release from the liver tissues. While, western blot and qRT-PCR results showed that the protein and mRNA expressions of inflammatory (TLR4/myd88/NF-κB) and necroptosis (RIPK1/RIPK3/MLKL) genes were up-regulated by AFB1 exposure. We suspect that signal crosstalk between TLR4 and TNF-α triggers inflammation and RIPK1/RIPK3 mediating necroptosis in AFB1-induced chicken liver injury. Curcumin can regulate the TLR4/RIPK signaling pathway, reduced oxidative stress biomarkers and inflammatory cytokines levels and attenuated the expression of necroptosis and inflammation genes altered by AFB1 to reduce necroptosis of chicken liver tissue. In conclusion, curcumin can protect against AFB1-induced necroptosis and inflammation by TLR4/RIPK pathway in chicken liver.

Ag/SiO2 nanocomposite mediated by Escherichia coli D8 and their antimicrobial potential

Silica (SiO2) has a fundamental role in the recuperation of plants in response to environmental stresses, besides the induction of resistance against plant diseases. Silver nanoparticles (AgNPs) have a superior antimicrobial activity. The combination between SiO2 and AgNPs is a promising approach due to their antimicrobial activity, biological activity, low toxicity, and high stability of the produced nanocomposite. The current study postulated a green method for silver/silica nanocomposite (Ag/SiO2NC) synthesis at room temperature using the crude metabolites of Escherichia coli D8 (MF062579) strain in the presence of sunlight. UV-Vis spectrophotometry, X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) analyses have characterized the biosynthesized nanocomposite. TEM study of Ag/SiO2NC showed an average particle size of ~32 – 48 nm whereas AgNPs showed a mean size of 18 – 24 nm. The negative charged Ag/SiO2NC (-31.0 mV) showed potent antimicrobial activity against Bacillus cereus ATCC6633, Klebsiella pneumoniae ATCC33495, Staphylococcus aureus (ATCC25923), E. coli (ATCC25922), Candida albicans (ATCC10231), and Botrytis cinerea (Pers: Fr.). The minimum inhibitory concentration (MIC) test showed a dose-dependent manner of Ag/SiO2NC antimicrobial action. MIC values of Ag/SiO2NC against the tested pathogens exhibited 125 and 6.25 μg.mL-1 as antibacterial and antifungal agents, respectively. TEM micrographs showed changes in the pathogens treated with Ag/SiO2NC including wrinkling, damage, and rupture of the bacterial cell membrane. In addition, the formation of a mucilage matrix connecting the hyphal cells, the appearance of big vacuoles and lipid droplets with severe leakage of cytoplasmic contents of the treated B. cinerea were also recorded.

Fission yeast polycystin Pkd2p promotes cell size expansion and antagonizes the Hippo-related SIN pathway.

Polycystins are conserved mechanosensitive channels whose mutations lead to the common human renal disorder autosomal dominant polycystic kidney disease (ADPKD). Previously, we discovered that the plasma membrane-localized fission yeast polycystin homolog Pkd2p is an essential protein required for cytokinesis; however, its role remains unclear. Here, we isolated a novel temperature-sensitive pkd2 mutant, pkd2-B42. Among the strong growth defects of this mutant, the most striking was that many mutant cells often lost a significant portion of their volume in just 5 min followed by a gradual recovery, a process that we termed 'deflation'. Unlike cell lysis, deflation did not result in plasma membrane rupture and occurred independently of cell cycle progression. The tip extension of pkd2-B42 cells was 80% slower than that of wild-type cells, and their turgor pressure was 50% lower. Both pkd2-B42 and the hypomorphic depletion mutant pkd2-81KD partially rescued mutants of the septation initiation network (SIN), a yeast Hippo-related signaling pathway, by preventing cell lysis, enhancing septum formation and doubling the number of Sid2p and Mob1p molecules at the spindle pole bodies. We conclude that Pkd2p promotes cell size expansion during interphase by regulating turgor pressure and antagonizes the SIN during cytokinesis. This article has an associated First Person interview with the first author of the paper.

Downregulation of macrophage migration inhibitory factor attenuates NLRP3 inflammasome mediated pyroptosis in sepsis-induced AKI

Sepsis-induced AKI (acute kidney injury) is considered an inflammation-related disease with high mortality. LPS-induced (Lipopolysaccharide) TLR4-NFκB pathway activation plays an important role in sepsis-induced AKI. Pyroptosis closely associated with inflammation response includes inflammasome formation, caspase1 activation and GSDMD N-terminal fragment cleavage that leads to cell membrane rupture and cell death, which may be related to the pathogenesis of sepsis-induced AKI. MIF (Macrophage migration inhibitory factor), associated with inflammation response, has been proved as a biomarker of sepsis, and perhaps regulate pyroptosis in sepsis-induced AKI. In this study, we focus on investigating the mechanism of MIF promoting pyroptosis in sepsis-induced AKI. MIF and pyroptosis-related proteins were up-regulated in kidney tissue of mice with CLP (cecum ligation puncture) surgery and in LPS-injured human kidney-2 (HK-2) cells. NLRP3 was down-regulated following the suppression of MIF topoisomerase activity by ISO-1 in kidney tissue of CLP mice. Knockdown of MIF alleviated NLRP3 inflammasome mediated pyroptosis in LPS-injured HK-2 cells. Meanwhile, we noted that phosphorylation of p65 was down-regulated by knockdown of MIF. Up-regulation of NLRP3 in response to LPS stimulation could be reversed by JSH-23, an inhibitor of NFκB pathway, but MIF was not affected. In conclusion, up-regulation of MIF in sepsis-induced AKI shows a renal damaged effect that aggravates NLRP3 inflammasome mediated cell pyroptosis through promoting phosphorylation of p65. This study demonstrated a novel mechanism of MIF regulating NLRP3 inflammasome mediated pyroptosis in sepsis-induced AKI.