SHP2 potentiates anti-PD-1 effectiveness through intervening cell pyroptosis resistance in triple-negative breast cancer.

Triple negative breast cancer (TNBC) presents a formidable challenge due to the lack of effective treatment modalities. Immunotherapy stands as a promising therapeutic approach; however, the emergence of drug resistance mechanisms within tumor cells, particularly those targeting apoptosis and pyroptosis, has hampered its clinical efficacy. SHP2 is intricately involved in diverse physiological processes, including immune cell proliferation, infiltration, and tumor progression. Nevertheless, the precise contribution of SHP2 to tumor cell pyroptosis resistance remains inadequately understood. Herein, we demonstrate that SHP2 inhibition hampers the proliferative, migratory, and invasive capabilities of TNBC, accompanied by noticeable alterations in cellular membrane architecture. Mechanistically, we provide evidence that SHP2 depletion triggers the activation of Caspase-1 and GSDMD, resulting in GSDMD-dependent release of LDH, IL-1ß, and IL-18. Furthermore, computational analyses and co-localization investigations substantiate the hypothesis that SHP2 may hinder pyroptosis through direct binding to JNK, thereby impeding JNK phosphorylation. Our cellular experiments further corroborate these findings by demonstrating that JNK inhibition rescues pyroptosis induced by SHP2 knockdown. Strikingly, in vivo experiments validate the suppressive impact of SHP2 knockdown on tumor progression via enhanced JNK phosphorylation. Additionally, SHP2 knockdown augments tumor sensitivity to anti-PD-1 therapy, thus reinforcing the pro-pyroptotic effects and inhibiting tumor growth. In summary, our findings elucidate the mechanism by which SHP2 governs TNBC pyroptosis, underscoring the potential of SHP2 inhibition to suppress cell pyroptosis resistance and its utility as an adjunctive agent for tumor immunotherapy.

Effect of Different Placement Sequences of Water on the Methane Adsorption Properties of Coal.

After the coal seam is injected with water, the moisture content in the coal body increases, which affects the output capacity of coalbed methane (CBM). In order to improve the effect of CBM mining, the classical anthracite molecular model has been selected. To analyze the influence of different placement orders of water and methane on the characteristics of coal-adsorbing methane from the micro point of view, a molecular simulation method is used for comprehensive consideration in the study. The results show that H2O does not change the mechanism of CH4 adsorption by anthracite, but it inhibits the adsorption of methane by anthracite. When water enters the system afterward, there arises an equilibrium pressure point where water plays the most significant role in inhibiting methane adsorption by anthracite coals, which increases with increasing moisture content. When water enters the system first, no equilibrium pressure point occurs. The excess adsorption of methane by anthracite when water enters second is higher. The reason is that H2O can replace CH4 at the higher energy adsorption sites of the anthracite structure, while CH4 can only be adsorbed at the lower energy sites, and some of CH4 is not adsorbed. For the coal samples with a low-moisture content system, the equivalent heat of adsorption of CH4 increases first rapidly and then slowly with the increase of pressure. However, it decreases with pressure in the high-moisture content system. The variation of the equivalent heat of adsorption further explains the variation of the magnitude of methane adsorption under different conditions.

Study on the difference of pore structure of anthracite under different particle sizes using low-temperature nitrogen adsorption method.

The low-temperature nitrogen adsorption test was used to study anthracite from Jiulishan coal mine with different particle size ranges of 60-80 mesh, 150-200 mesh, and > 200 mesh. The adsorption isotherm, adsorption capacity, pore volume, pore specific surface area, and average pore diameter of coal samples were analyzed by BET and DFT models in order to study the influence of particle size on the pore structure of anthracite and determine the optimal range of particle size for low-temperature nitrogen adsorption test. The results indicate that the particle size plays a significant effect on the pore structure of anthracite and the adsorption capacity of soft coal is less affected by particle size, while hard coal is substantially affected by particle size. The adsorption capacity of hard coal with particle size of > 200 mesh is increased by 7 times when compared with the particle size of 60-80 mesh, indicating that the gas molecular mobility hindrance decline and pore connectivity improves with the decrease of particle size. The average pore diameter of hard coal decreases continuously from 3.1424 to 2.854 nm, while that of soft coal expands from 2.8947 to 3.2515 nm and then to 3.0362 nm with the decrease of particle size. The effects of particle size on the pore surface area of soft and hard coal are concentrated within the < 10 nm pore aperture. Effect of particle size on hard coal pore volume is mainly focused in the pore size < 10 nm, whereas that of soft coal is primarily concentrated in the pore with aperture ranges of 2-100 nm. When the particle sizes varies from 60-80 mesh to 150-200 mesh, the collapse of large pore of hard coal appears better than that of closed pore. When the particle size of hard coal reaches > 200 mesh, the collapse of closed pores and the damage to small pores are stronger than the collapse of large pores. The fractal dimensions with relative pressure of 0-0.20 and 0.20-0.995 are defined as D1 and D2, respectively, and when the fractal dimension D1 increases, the surface roughness and structural complexity of coal samples increase with the decrease of anthracite particle size, while the fractal dimension D2 shows the opposite trend, which indicates that anthracite of smaller particle size possess higher adsorption capacity. Therefore, 150-200 mesh is recommended as the preferred anthracite particle size in low-temperature nitrogen adsorption test.

Assessing the Impact of Green Transformation on Ecological Well-Being Performance: A Case Study of 78 Cities in Western China.

The contradiction between the endless pursuit of material possessions and finite natural resources hampers ecological well-being performance (EWP) improvement. Green transformation, recognized as an emerging strategy in sustainable development, can help to coordinate ecological, social, and economic growth by optimizing resource usage, with the ultimate objective of enhancing EWP. This research quantifies how green transformation influences EWP by using panel data from 78 prefecture-level cities in western China from 2012 to 2019. Using the super-SBM and entropy weight models, we assess the EWP and green transformation index (GTI) of 78 prefecture-level cities in western China. On this basis, we quantify the spatial characteristics of EWP by an analysis of the Theil index and spatial autocorrelation. Finally, we examine how GTI affects EWP using the Spatial Durbin model. The results demonstrate that the GTI can raise the EWP of local and nearby cities in western China. According to a GTI analysis of internal indicators, the industrial solid waste usage, harm-less treatment rate of domestic waste, savings level, and R&D expenditure significantly affect EWP. In contrast, the soot emission and consumption levels impede EWP advancement. The analysis of effect decomposition indicates that the sewage treatment rate, expenditure on science and technology, and green patents have a significant spatial spillover effect on the improvement of EWP.

Development and Evaluation of a PSMA-Targeted Nanosystem Co-Packaging Docetaxel and Androgen Receptor siRNA for Castration-Resistant Prostate Cancer Treatment.

Primary prostate cancer (PC) progresses to castration-resistant PC (CRPC) during androgen deprivation therapy (ADR) in early stages of prostate cancer. Thus, rather than blocking the androgen-related pathway further, docetaxel (DTX)-based therapy has become the most effective and standard first-line chemotherapy for CRPC. Although the therapy is successful in prolonging the survival of patients with CRPC, chemotherapy resistance develops due to the abnormal activation of the androgen receptor (AR) signaling pathway. Thus, to optimize DTX efficacy, continued maximum suppression of androgen levels and AR signaling is required. Here, we designed a prostate-specific membrane antigen (PSMA)-targeted nanosystem to carry both DTX and AR siRNA (Di-PP/AR-siRNA/DTX) for CRPC treatment. Specifically, DTX was encapsulated into the hydrophobic inner layer, and the AR siRNA was then condensed with the cationic PEI block in the hydrophilic outer layer of the PEI-PLGA polymeric micelles. The micelles were further coated with PSMA-targeted anionic polyethylene glycol-polyaspartic acid (Di-PEG-PLD). In vitro and in vivo results demonstrated that the resulting Di-PP/AR-siRNA/DTX exhibited prolonged blood circulation, selective targeting, and enhanced antitumor effects. Consequently, Di-PP/AR-siRNA/DTX holds great potential for efficient CRPC treatment by combining chemotherapy and siRNA silencing of androgen-related signaling pathways.

Hydrothermal Synthesis of Hierarchical SnO2 Nanostructures for Improved Formaldehyde Gas Sensing.

The indoor environment of buildings affects people's daily life. Indoor harmful gases include volatile organic gas and greenhouse gas. Therefore, the detection of harmful gas by gas sensors is a key method for developing green buildings. The reasonable design of SnO2-sensing materials with excellent structures is an ideal choice for gas sensors. In this study, three types of hierarchical SnO2 microspheres assembled with one-dimensional nanorods, including urchin-like microspheres (SN-1), flower-like microspheres (SN-2), and hydrangea-like microspheres (SN-3), are prepared by a simple hydrothermal method and further applied as gas-sensing materials for an indoor formaldehyde (HCHO) gas-sensing test. The SN-1 sample-based gas sensor demonstrates improved HCHO gas-sensing performance, especially demonstrating greater sensor responses and faster response/recovery speeds than SN-2- and SN-3-based gas sensors. The improved HCHO gas-sensing properties could be mainly attributed to the structural difference of smaller nanorods. These results further indicate the uniqueness of the structure of the SN-1 sample and its suitability as HCHO- sensing material.

Novel brain-targeted nanomicelles for anti-glioma therapy mediated by the ApoE-enriched protein corona in vivo.

BACKGROUND: The interactions between nanoparticles (NPs) and plasma proteins form a protein corona around NPs after entering the biological environment, which provides new biological properties to NPs and mediates their interactions with cells and biological barriers. Given the inevitable interactions, we regard nanoparticle‒protein interactions as a tool for designing protein corona-mediated drug delivery systems. Herein, we demonstrate the successful application of protein corona-mediated brain-targeted nanomicelles in the treatment of glioma, loading them with paclitaxel (PTX), and decorating them with amyloid ß-protein (Aß)-CN peptide (PTX/Aß-CN-PMs). Aß-CN peptide, like the Aß1-42 peptide, specifically binds to the lipid-binding domain of apolipoprotein E (ApoE) in vivo to form the ApoE-enriched protein corona surrounding Aß-CN-PMs (ApoE/PTX/Aß-CN-PMs). The receptor-binding domain of the ApoE then combines with low-density lipoprotein receptor (LDLr) and LDLr-related protein 1 receptor (LRP1r) expressed in the blood-brain barrier and glioma, effectively mediating brain-targeted delivery. METHODS: PTX/Aß-CN-PMs were prepared using a film hydration method with sonication, which was simple and feasible. The specific formation of the ApoE-enriched protein corona around nanoparticles was characterized by Western blotting analysis and LC-MS/MS. The in vitro physicochemical properties and in vivo anti-glioma effects of PTX/Aß-CN-PMs were also well studied. RESULTS: The average size and zeta potential of PTX/Aß-CN-PMs and ApoE/PTX/Aß-CN-PMs were 103.1 nm, 172.3 nm, 7.23 mV, and 0.715 mV, respectively. PTX was efficiently loaded into PTX/Aß-CN-PMs, and the PTX release from rhApoE/PTX/Aß-CN-PMs exhibited a sustained-release pattern in vitro. The formation of the ApoE-enriched protein corona significantly improved the cellular uptake of Aß-CN-PMs on C6 cells and human umbilical vein endothelial cells (HUVECs) and enhanced permeability to the blood-brain tumor barrier in vitro. Meanwhile, PTX/Aß-CN-PMs with ApoE-enriched protein corona had a greater ability to inhibit cell proliferation and induce cell apoptosis than taxol. Importantly, PTX/Aß-CN-PMs exhibited better anti-glioma effects and tissue distribution profile with rapid accumulation in glioma tissues in vivo and prolonged median survival of glioma-bearing mice compared to those associated with PMs without the ApoE protein corona. CONCLUSIONS: The designed PTX/Aß-CN-PMs exhibited significantly enhanced anti-glioma efficacy. Importantly, this study provided a strategy for the rational design of a protein corona-based brain-targeted drug delivery system. More crucially, we utilized the unfavorable side of the protein corona and converted it into an advantage to achieve brain-targeted drug delivery.

Development of Mitomycin C-Loaded Nanoparticles Prepared Using the Micellar Assembly Driven by the Combined Effect of Hydrogen Bonding and π-π Stacking and Its Therapeutic Application in Bladder Cancer.

Micelle is mainly used for drug delivery and is prepared from amphiphilic block copolymers. It can be formed into an obvious core-shell structure that can incorporate liposoluble drugs. However, micelles are not suitable for the encapsulation of water-soluble drugs, and it is also difficult to maintain stability in the systemic circulation. To solve these problems, a type of polymer material, Fmoc-Lys-PEG and Fmoc-Lys-PEG-RGD, was designed and synthesized. These copolymers could self-assemble into micelles driven by π-π stacking and the hydrophobic interaction of 9-fluorenylmethoxycarbony (Fmoc) and, at the same time, form a framework for a hydrogen-bonding environment in the core. Mitomycin C (MMC), as a water-soluble drug, can be encapsulated into micelles by hydrogen-bonding interactions. The interaction force between MMC and the polymers was analyzed by molecular docking simulation and Fourier transform infrared (FTIR). It was concluded that the optimal binding conformation can be obtained, and that the main force between the MMC and polymers is hydrogen bonding. Different types of MMC nanoparticles (NPs) were prepared and the physicochemical properties of them were systematically evaluated. The pharmacodynamics of the MMC NPs in vitro and in vivo were also studied. The results show that MMC NPs had a high uptake efficiency, could promote cell apoptosis, and had a strong inhibitory effect on cell proliferation. More importantly, the as-prepared NPs could effectively induce tumor cell apoptosis and inhibit tumor growth and metastasis in vivo.

Efficient Anti-Glioma Therapy Through the Brain-Targeted RVG15-Modified Liposomes Loading Paclitaxel-Cholesterol Complex.

BACKGROUND: Glioma is the most common primary malignant brain tumor with a dreadful overall survival and high mortality. One of the most difficult challenges in clinical treatment is that most drugs hardly pass through the blood-brain barrier (BBB) and achieve efficient accumulation at tumor sites. Thus, to circumvent this hurdle, developing an effectively traversing BBB drug delivery nanovehicle is of significant clinical importance. Rabies virus glycoprotein (RVG) is a derivative peptide that can specifically bind to nicotinic acetylcholine receptor (nAChR) widely overexpressed on BBB and glioma cells for the invasion of rabies virus into the brain. Inspired by this, RVG has been demonstrated to potentiate drugs across the BBB, promote the permeability, and further enhance drug tumor-specific selectivity and penetration. METHODS: Here, we used the RVG15, rescreened from the well-known RVG29, to develop a brain-targeted liposome (RVG15-Lipo) for enhanced BBB permeability and tumor-specific delivery of paclitaxel (PTX). The paclitaxel-cholesterol complex (PTX-CHO) was prepared and then actively loaded into liposomes to acquire high entrapment efficiency (EE) and fine stability. Meanwhile, physicochemical properties, in vitro and in vivo delivery efficiency and therapeutic effect were investigated thoroughly. RESULTS: The particle size and zeta potential of PTX-CHO-RVG15-Lipo were 128.15 ± 1.63 nm and -15.55 ± 0.78 mV, respectively. Compared with free PTX, PTX-CHO-RVG15-Lipo exhibited excellent targeting efficiency and safety in HBMEC and C6 cells, and better transport efficiency across the BBB in vitro model. Furthermore, PTX-CHO-RVG15-Lipo could noticeably improve the accumulation of PTX in the brain, and then promote the chemotherapeutic drugs penetration in C6luc orthotopic glioma based on in vivo imaging assays. The in vivo antitumor results indicated that PTX-CHO-RVG15-Lipo significantly inhibited glioma growth and metabasis, therefore improved survival rate of tumor-bearing mice with little adverse effect. CONCLUSION: Our study demonstrated that the RVG15 was a promising brain-targeted specific ligands owing to the superior BBB penetration and tumor targeting ability. Based on the outstanding therapeutic effect both in vitro and in vivo, PTX-CHO-RVG15-Lipo was proved to be a potential delivery system for PTX to treat glioma in clinic.

Efficient antiglioblastoma therapy in mice through doxorubicin-loaded nanomicelles modified using a novel brain-targeted RVG-15 peptide.

Glioblastoma (GBM) is an aggressive malignancy and therapeutic options are limited due to the presence of the blood-brain barrier (BBB). RVG-29, a 29-amino-acid polypeptide derived from the rabies virus glycoprotein (RVG), has excellent brain-targeted capacity across the BBB. We reduced the size of this peptide to get a15-amino-acid polypeptide (RVG-15), while retaining its brain-targeted capacity across the BBB. First, we synthesized a novel nanocarrier RVG-15-PEG2000-DSPE. Next, DOX-loaded polymeric micelles (DOX RVG-15-PMs) were prepared in an electrostatic interaction-dependent manner. Finally, we evaluated its antitumor benefits in vitro at the cellular level and in vivo using an in situ tumour-bearing mouse model. MALDI-TOF-MS and FTIR spectra confirmed the successful synthesis of the novel nanocarrier. The prepared DOX RVG-15-PMs displayed even size distribution, a high entrapment efficiency and satisfactory in vitro release behaviour. In vitro blank RVG-15-PMs were excellent, safe and highly biocompatible as drug delivery carriers. DOX-loaded micelles were easily taken up by C6 cells and could effectively inhibit cancer development and metastasis. In vivo, DOX RVG-15-PMs delayed weight loss, prevented cancer cell metastasis and accelerated cancer cell apoptosis in tumour-bearing mice. Our novel brain-targeted nanocarrier is highly feasible, while DOX RVG-15-PMs exert significant antiglioma effects, both in vitro and in vivo.

Enhancing anti-melanoma outcomes in mice using novel chitooligosaccharide nanoparticles loaded with therapeutic survivin-targeted siRNA.

Melanoma anti-tumor therapy remains a challenge. SiRNA-based therapies provide a powerful means, but limitations remain in its pharmaceutical applications owing to the lack of highly efficient delivery systems. In this study, to improve the siRNA delivery efficiency of chitooligosaccharide (COS), phenylboronic acid (PBA)-modified COS was synthesized and structurally characterized. PBA-modified COS was used to deliver survivin-targeted siRNA for melanoma treatment. The siRNA-loaded nanoparticles were prepared by a synergetic assembly of electrostatic complexation and chemical cross-linking. The particle size and zeta potential were characterized by dynamic light scattering, and transmission electron microscopy was utilized to observe the morphology of the nanoparticles. The cellular uptake of nanoparticles on B16F10 cells was studied by flow cytometry and confocal laser scanning microscopy. A luciferase reporter gene assay determined the gene silencing efficiency of different nanoparticles. As a result, the novel nanoparticles remarkably inhibited the proliferation of B16F10 cells in vitro and significantly inhibited the growth and metastasis of melanoma in vivo. In conclusion, PBA-modified COS can serve as a promising carrier for siRNA delivery in the field of anti-tumor therapy.

Experimental Investigation on Diffusion Coefficients of CH4 in Coal under High-Temperature and -Pressure Conditions.

Here, a self-developed experimental system of diffusion at high temperatures and pressures was utilized to clarify the impacts of high pressure and temperature (303, 323, 343, and 363 K; 2, 6, 12, and 20 MPa) and coal ranks on diffusion properties in coal. At constant temperature and pressure, the diffusion coefficients of CH4 gradually decrease with increasing particle size and increase gradually with the increasing pressure and temperature. However, the diffusion coefficients first decrease and then increase with the increasing coal rank. The minimum diffusion coefficients occur at about R o,max = 1.7%. The temperature and pressure sensitivity of CH4 diffusion was quantified via the experimental data. The increase extent first increases and then decreases with the increasing pressure. The peak pressure for the increase extent was 6 MPa for all coals. The increments of diffusion rate per pressure unit were 1.50, 0.90, and 0.61%, indicating that the impact of pressure at the low-pressure stage (2-6 MPa) was more significant than that at the high-pressure stage (6-20 MPa). At the same pressure, the diffusion rates overall increase with the increasing temperature. At the low-pressure stage (2-6 MPa), the impacts of pressure were more significant than at the high-pressure stage. However, as for the temperature dependence, the impacts of temperature were more significant at the high-pressure stage than at the low-pressure stage.

Improving anti-tumor outcomes for colorectal cancer therapy through in situ thermosensitive gel loading harmine.

Colorectal cancer is a common malignant tumor that seriously endangers human health. Harmine (HM), a natural product, has been shown to have a significant inhibitory effect on various cancers. However, systemic injection of HM can cause central nervous toxicity, which limits its clinical application. Local administration of HM overcomes this problem to a certain extent. In this study, we prepared an in situ thermosensitive HM gel preparation (HM gel), and used it to treat colon cancer with reduced toxic side effects and prolonged residence time of HM at the tumor site. We employed a central composite design and response surface methodology to optimize the formulation, and evaluated the physicochemical properties, rectal retention capacity, and in vitro and in vivo antitumor effects of HM gel on colon 26 tumor cells. The results showed that HM gel had a significant inhibitory effect on the growth of colon 26 cells in vitro. In an orthotopic tumor-bearing mouse model, HM gel exhibited an obvious inhibitory effect on tumor growth and metastasis, and significantly prolonged the survival period. In conclusion, HM gel exhibited significant anti-tumor effects on colon cancer, and therefore presents a promising formulation for the treatment of colorectal cancer.

Cry1Ac Protoxin and Its Activated Toxin from Bacillus thuringiensis Act Differentially during the Pathogenic Process.

Although the new dual model of the Bacillus thuringiensis insecticidal mechamism indicated that both Cry1A protoxin and activated toxin have the potency to kill insects, the difference in the toxic pathways elicited by the protoxin and activated toxin was less understood at the molecular level. Through utilizing the CF-203 cell line derived from the midgut of Choristoneura fumiferana, we found that there existed obvious differences in the binding sites and endocytosis pathways for the two forms of Cry1Ac. In addition, it was revealed that Cry1Ac protoxin existed predominantly in the midgut of Plutella xylostella at the early stage after ingesting Cry1Ac crystals, which brought about obvious damage to the midgut epithelium and exhibited different binding sites on the brush border membrane vesicle compared to the toxin. These findings supported the dual mode of action of B. thuringiensis Cry1A proteins and improved our understanding of the molecular features that contribute to the protoxin toxicity.

The conserved cysteine residues in Bacillus thuringiensis Cry1Ac protoxin are not essential for the bipyramidal crystal formation.

To evaluate the function of conserved cysteine residues in Cry1Ac protoxin, we constructed a series of Cry1Ac mutants in which single or multiple cysteine residues were replaced with serine. It was found that cysteine substitution had little effect on the protoxin expression and bipyramidal crystal formation. Bioassays using Plutella xylostella larvae showed that two mutants with fourteen cysteine residues in the C-terminal half and all sixteen residues replaced had similar toxicity as wildtype Cry1Ac protoxin. Our study suggests that the conserved cysteine resudues in the Cry1Ac protoxin are not essential for deposition into a bipyramidal crystal even though the C-terminal half was directly involved in crystal formation.

Solubility enhancement of Cry2Aa crystal through carboxy-terminal extension and synergism between the chimeric protein and Cry1Ac.

It was reported that the highly conserved C-terminal region of Bacillus thuringiensis Cry1A protoxins was very important for parasporal crystal formation and solubility feature in alkaline environment. In order to improve the solubilization efficiency of Cry2Aa crystal, the coding sequences of Cry2Aa protein and the C-terminal half of Cry1Ac were fused seamlessly through Red/ET homologous recombination and expressed in an acrystalliferous B. thuringiensis strain under the control of the cry1Ac promoter and terminator. Microscopic observation revealed that the recombinant strain containing the chimeric gene cry2Aa-1Ac produced distinct parasporal inclusion with semispherical to approximately cuboidal shape during sporulation. SDS-PAGE analysis showed that this strain expressed stable 130-kDa Cry2Aa-1Ac chimeric protein, which was confirmed to be the correctly expressed product by LC-MS/MS. The chimeric protein inclusion could be effectively dissolved at pH 10.5 and activated by trypsin like the parental Cry1Ac crystal. While, the parental Cry2Aa crystal exhibited very low solubility under this condition. Bioassays against third-instar larvae of Helicoverpa armigera proved that the chimeric protein was more toxic than Cry2Aa. Additionally, synergistic effect was clearly detected between the chimeric protein and Cry1Ac against H. armigera, while there was only additive effect for the combination of wild Cry2Aa and Cry1Ac. These results indicated that the developed chimeric protein might serve as a potent insecticidal toxin used in the field against lepidopteran pests.

Aggravated chronic brain injury after focal cerebral ischemia in aquaporin-4-deficient mice.

The water channel aquaporin-4 (AQP4) is important in brain water homeostasis, and is also involved in astrocyte growth and glial scar formation. It has been reported that AQP4 deficiency attenuates acute ischemic brain injury as a result of reducing cytotoxic edema. Here, we determined whether AQP4 deficiency influences chronic brain injury after focal cerebral ischemia induced by 30 min of middle cerebral artery occlusion (MCAO). AQP4(-/-) mice exhibited a lower survival rate and less body weight gain than wild-type mice, but their neurological deficits were similar to wild-type mice during 35 days after MCAO. At 35 days after MCAO, AQP4(-/-) mice showed more severe brain atrophy and cavity formation in the ischemic hemisphere as well as more neuronal loss in the hippocampus. Furthermore, astrocyte proliferation and glial scar formation were impaired in AQP4(-/-) mice. Therefore, AQP4 deficiency complicated by astrocyte dysfunction aggravates chronic brain injury after focal cerebral ischemia, suggesting that AQP4 may be important in the chronic phase of the post-ischemic recovery process.

Luteolin inhibits apoptosis and improves cardiomyocyte contractile function through the PI3K/Akt pathway in simulated ischemia/reperfusion.

Luteolin, a naturally occurring polyphenol flavonoid, has demonstrated to exert myocardial protection effects. However, the mechanisms have not been fully elucidated. In the present study, we investigated whether luteolin pretreatment was associated with cardioprotection in a rat ischemia/reperfusion (I/R) model. Luteolin significantly not only restored contractility of the left ventricle, but also reduced the infarct size and lactate dehydrogenase leakage during I/R. In addition, luteolin pretreatment significantly improved cardiomyocyte shortening amplitude, decreased the apoptotic rate, upregulated Bcl-2 expression, downregulated Bax expression and raised the Bcl-2/Bax ratio under a simulated ischemia/reperfusion (SI/R) condition. Moreover, luteolin pretreatment increased protein kinase B (Akt) phosphorylation, phospholamban phosphorylation and the expression of sarcoplasmic reticulum calcium ATPase following SI/R. The phosphoinositide 3-kinase (PI3K)/Akt pathway is one of the most important intracellular survival signal pathways. To determine whether luteolin-induced cardioprotection was mediated by the PI3K/Akt pathway, we utilized the PI3K inhibitor LY294002. Inhibition of Akt activity markedly abolished luteolin-induced positive contraction and inhibition of apoptosis in SI/R cardiomyocytes. These results showed that luteolin inhibits apoptosis and improves cardiomyocyte contractile function at least partly through the PI3K/Akt pathway in SI/R.

Salvianolic acid A demonstrates cardioprotective effects in rat hearts and cardiomyocytes after ischemia/reperfusion injury.

Salvianolic acid A (Sal A), the water-soluble component from the root of the Salvia miltiorrhiza plant, possesses antioxidant, antiproliferative, and antiplatelet properties. However, whether it plays a role in the protection against ischemia-reperfusion (I/R) injury in rat hearts has yet to be elucidated. In the present study, we tested cell viability, shortening amplitude, necrosis, apoptosis, and the expression levels of Akt, phosphorylated Akt, Bcl-2, Bax, and caspase-3 after 3-hour simulated ischemia and 2- or 6-hour simulated reperfusion in cardiomyocytes. We further observed the contractile function and infarct size in isolated hearts after they were subjected to global 30-minute ischemia and 120-minute reperfusion. Pretreatment with Sal A markedly increased cell viability and shortening amplitude while reducing evidence of necrosis and apoptosis in the cells. In addition, the expression of Bcl-2 was upregulated and Bax was downregulated, thereby increasing the Bcl-2/Bax ratio. Sal A inhibited the activation of caspase-3 as well. The results also showed that Sal A significantly increased phosphorylation of Akt and that this phosphorylation can be partially inhibited by phosphoinositide 3-kinase/Akt inhibitor. Furthermore, Sal A improved I/R-induced myocardial contractile function and reduced infarct size. In summary, our results showed that Sal A prevents I/R-induced myocardial damage by reducing necrosis and apoptosis in isolated rat hearts and cardiomyocytes.