Dapagliflozin improves diabetic cognitive impairment via indirectly modulating the mitochondria homeostasis of hippocampus in diabetic mice.

Cognitive impairment is increasingly recognized as an important comorbidity of diabetes progression; however, the underlying molecular mechanism is unclear. Dapagliflozin, an inhibitor of sodium-glucose co-transporter 2 (SGLT2), has shown promising effects against diabetes in rodent experiments and human clinical assays. This study aimed to determine the underlying mechanism and examine the effect of dapagliflozin on diabetic cognitive impairment. To create an in vivo model of diabetic cognitive impairment, streptozotocin (STZ)-induced diabetic mice were used. Dapagliflozin was administered to mice for 8 weeks. The context fear condition and Morris water maze test was used to evaluate mice's behavioral change. Western blotting was used to evaluate protein expression. Hematoxylin and eosin (HE) and Nissl staining were applied to monitor morphological and structural changes. Congo red staining was performed to identify the formation of senile plaques. Mitochondria morphology was examined using a transmission electron microscope, and blood flow in the mouse cerebral cortex was measured using a laser Doppler imaging assay. Comparison to the diabetes mellitus (DM) group, the dapagliflozin group had lower glucose levels. Behavioral studies have shown that dapagliflozin can restore memory deficits in diabetic mice. The murky cell membrane edges and Nissl bodies more difficult to identify in the DM group were revealed by HE and Nissl staining, which were both improved by dapagliflozin treatment. Dapagliflozin inhibited the progression of Aß generation and the reduced cerebral blood flow in the DM group was rescued. After dapagliflozin treatment, damaged mitochondria and lack of SGLT2 in the hippocampus and cortex of diabetic mice were repaired. Diabetes-induced cognitive dysfunction was attenuated by dapagliflozin and the effect was indirect rather than direct.

Mechanistic insights into the amelioration effects of lipopolysaccharide-induced acute lung injury by baicalein: An integrated systems pharmacology study and experimental validation.

BACKGROUND: Acute lung injury is an acute progressive respiratory failure caused by several of non-cardiogenic factors which involves in excessive amplification or uncontrolled inflammatory response. OBJECTIVES: In this study, we investigated the protective effect of baicalein against acute lung injury induced by LPS and explored the underlying mechanisms. METHODS: Forty-eight SPF male C57BL/6 mice were randomly divided into normal group, model group, dexamethasone group and baicalein low-dose, medium-dose and high-dose groups. After 5 days of adaptive feeding, the mice were intraperitoneally injected with LPS and dissected after 12 h. Hematoxylin-eosin staining, ELISA assay, immunofluorescence assay and Western-Blot were applied to appraise microstructural changes and protein expressions of lung tissues. Systems pharmacology study was used to evaluate the protection of baicalein on acute lung injury. FINDINGS: The results showed that baicalein administration could significantly inhibit LPS-induced lung morphological changes, inhibit inflammatory response and pyroptosis. A total of forty-three potential targets of baicalein and acute lung injury were obtained. And PI3K-Akt, TNF and NF-κB were mainly signaling pathways. It is worth mentioning that this experiment also confirmed that NLRP3, caspase-1 and other inflammasome are involved in pyroptosis. CONCLUSION: Baicalein has protected against LPS-induced lung tissues injury via inhibiting inflammatory response and pyroptosis.

Ethyl ferulate protects against lipopolysaccharide-induced acute lung injury by activating AMPK/Nrf2 signaling pathway.

Ethyl ferulate (EF) is abundant in Rhizoma Chuanxiong and grains (e.g., rice and maize) and possesses antioxidative, antiapoptotic, antirheumatic, and anti-inflammatory properties. However, its effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is still unknown. In the present study, we found that EF significantly alleviated LPS-induced pathological damage and neutrophil infiltration and inhibited the gene expression of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6) in murine lung tissues. Moreover, EF reduced the gene expression of TNF-α, IL-1ß, IL-6, and iNOS and decreased the production of NO in LPS-stimulated RAW264.7 cells and BMDMs. Mechanistic experiments revealed that EF prominently activated the AMPK/Nrf2 pathway and promoted Nrf2 nuclear translocation. AMPK inhibition (Compound C) and Nrf2 inhibition (ML385) abolished the beneficial effect of EF on the inflammatory response. Furthermore, the protective effect of EF on LPS-induced ALI was not observed in Nrf2 knockout mice. Taken together, the results of our study suggest that EF ameliorates LPS-induced ALI in an AMPK/Nrf2-dependent manner. These findings provide a foundation for developing EF as a new anti-inflammatory agent for LPS-induced ALI/ARDS therapy.

Emerging Benefits: Pathophysiological Functions and Target Drugs of the Sigma-1 Receptor in Neurodegenerative Diseases.

The sigma-1 receptor (Sig-1R) is encoded by the SIGMAR1 gene and is a nonopioid transmembrane receptor located in the mitochondrial-associated endoplasmic reticulum membrane (MAM). It helps to locate endoplasmic reticulum calcium channels, regulates calcium homeostasis, and acts as a molecular chaperone to control cell fate and participate in signal transduction. It plays an important role in protecting neurons through a variety of signaling pathways and participates in the regulation of cognition and motor behavior closely related to neurodegenerative diseases. Based on its neuroprotective effects, Sig-1R has now become a breakthrough target for alleviating Alzheimer's disease and other neurodegenerative diseases. This article reviews the most cutting-edge research on the function of Sig-1R under normal or pathologic conditions and target drugs of the sigma-1 receptor in neurodegenerative diseases.

Itaconate ameliorates methicillin-resistant Staphylococcus aureus-induced acute lung injury through the Nrf2/ARE pathway.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) are a critical predisposing factor of sepsis in the clinic. As a product of human energy metabolism and immune response, itaconate can effectively reduce inflammation in the body. This research employed 4-octyl itaconate (4-OI) to illustrate that itaconate exerted anti-inflammatory effects to protect the body from acute lung injury (ALI) induced by MRSA. METHODS: HE staining and immunohistochemistry are used to evaluate the MRSA-induced ALI in mice. WB and qPCR were used to verify the effect of 4-OI on inflammation and oxidative stress caused by MRSA. Molecular docking was used to verify the binding sites of 4-OI and Keap1. RESULTS: We demonstrated that 4-OI treatment increased the survival ratio, attenuated the pathological damage, inhibited neutrophil infiltration, and reduced lung bacterial burden in the mouse MRSA pneumonia model. 4-OI decreased the expression of inflammatory factors by stimulating the Nrf2 in vivo and in vitro. Furthermore, 4-OI exerted its effect by promoting nuclear transport of Nrf2 in vitro. The results of molecular docking indicated that 4-OI bound to the pocket of Keap1 and exerted a stable interaction. Both Nrf2 inhibitors (ML385) and Nrf2-/- mice abolished the protective effect of 4-OI on MRSA-induced inflammation both in vitro and in vivo. CONCLUSIONS: 4-OI prevents lung damage caused by MRSA bacteremia via activating Nrf2/ARE pathway.

Sodium Propionate Enhances Nrf2-Mediated Protective Defense Against Oxidative Stress and Inflammation in Lipopolysaccharide-Induced Neonatal Mice.

BACKGROUND: Alveolar arrest and the impaired angiogenesis caused by chronic inflammation and oxidative stress are two main factors in bronchopulmonary dysplasia (BPD). Short-chain fatty acids (SCFAs), especially propionate, possess anti-oxidant and anti-inflammatory effects. The present study was designed to examine the roles of sodium propionate (SP) on lipopolysaccharide (LPS)-challenged BPD and its potential mechanisms. METHODS: WT, Nrf2-/- mice and pulmonary microvascular endothelial cells (HPMECs) were used in this study. LPS was performed to mimic BPD model both in vivo and vitro. Lung histopathology, inflammation and oxidative stress-related mRNA expressions in lungs involved in BPD pathogenesis were investigated. In addition, cell viability and angiogenesis were also tested. RESULTS: The increased nuclear factor erythroid 2-related factor (Nrf2) and decreased Kelch-like ECH-associated protein-1 (Keap-1) expressions were observed after SP treatment in the LPS-induced neonatal mouse model of BPD. In LPS-induced wild-type but not Nrf2-/- neonatal mice, SP reduced pulmonary inflammation and oxidative stress and exhibited obvious pathological alterations of the alveoli. Moreover, in LPS-evoked HPMECs, SP accelerated Nrf2 nuclear translocation presented and exhibited cytoprotective and pro-angiogenesis effects. In addition, SP diminished the LPS-induced inflammatory response by blocking the activation of nuclear factor-kappa B pathway. Moreover, pretreatment with ML385, an Nrf2 specific inhibitor, offsets the beneficial effects of SP on inflammation, oxidative stress and angiogenesis in LPS-evoked HPMECs. CONCLUSION: SP protects against LPS-induced lung alveolar simplification and abnormal angiogenesis in neonatal mice and HPMECs in an Nrf2-dependent manner.

High expression of heme oxygenase-1 in tumor-associated macrophages characterizes a poor-prognosis subtype in nasopharyngeal carcinoma.

Tumor-associated macrophages (TAMs) are important components of the tumor microenvironment, which are characterized by pro-tumor M2 phenotype and correlate with poor survival of nasopharyngeal carcinoma (NPC). Heme oxygenase-1 (HO-1) plays a crucial role in macrophage polarization toward M2 phenotype, but its prognosis significance in NPC has been rarely determined. To gain insights into the HO-1 expression profile and to determine the clinical significance of HO-1 in NPC, we performed immunohistochemistry analyses in 126 NPC specimens. CD163, a highly specific marker of M2 macrophages, was used as a surrogate for the polarization state of TAMs. Our results showed that high expression of HO-1 and CD163 were detected in TAMs for 57.9% (73/126) and 61.9% (78/126) of the studied patients, and both of them were significantly associated with worse survival. Additionally, a significant correlation between the intensities of HO-1 and CD163 was identified, and HO-1 exhibited a superior ability in predicting survival compared with CD163. Our study revealed for the first time that overexpression of HO-1 characterized a poor-prognosis subtype in NPC. Individualized therapy targeting HO-1 might serve as a promising treatment modality for NPC.

Sophoricoside attenuates lipopolysaccharide-induced acute lung injury by activating the AMPK/Nrf2 signaling axis.

Sophoricoside (SOP), an isoflavone glycoside isolated from seed of Sophora japonica L., has been reported to have various pharmacological activities, including anti-cancer, anti-allergy and anti-inflammation. However, the effect of SOP on lipopolysaccharides (LPS)-acute lung injury (ALI) is completely unclear. Here, we found that SOP pretreatment significantly ameliorated LPS-induced pathological damage, tissue permeability, neutrophil infiltration and the production of pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) in a murine model of ALI. Besides, SOP reduced the production of pro-inflammatory mediators such as iNOS, NO and inflammatory cytokines including TNF-α, IL-1ß and IL-6 in LPS-stimulated RAW264.7 cells and bone marrow derived macrophages. Interestingly, treatment with SOP exhibited no effect on the activation of NF-κB and MAPKs in macrophages but prominently accelerated the expression and nuclear translocation of Nrf2. By using ML385, a specific Nrf2 inhibitor, we found that inhibition of Nrf2 abolished the inhibitory effect of SOP on LPS-induced iNOS expression, NO production as well as pro-inflammatory cytokine generation. SOP also activated AMPK, an upstream protein of Nrf2, under LPS stimuli. Furthermore, we demonstrated that the accelerated expression of Nrf2 induced by SOP was reversed by interference with the AMPK inhibitor Compound C. Taken together, our results suggested that SOP attenuated LPS-induced ALI in AMPK/Nrf2 dependent manner and indicated that SOP might be a potential therapeutic candidate for treating ALI/ARDS.

Nrf2 protects against seawater drowning-induced acute lung injury via inhibiting ferroptosis.

BACKGROUND: Ferroptosis is a new type of nonapoptotic cell death model that was closely related to reactive oxygen species (ROS) accumulation. Seawater drowning-induced acute lung injury (ALI) which is caused by severe oxidative stress injury, has been a major cause of accidental death worldwide. The latest evidences indicate nuclear factor (erythroid-derived 2)-like 2 (Nrf2) suppress ferroptosis and maintain cellular redox balance. Here, we test the hypothesis that activation of Nrf2 pathway attenuates seawater drowning-induced ALI via inhibiting ferroptosis. METHODS: we performed studies using Nrf2-specific agonist (dimethyl fumarate), Nrf2 inhibitor (ML385), Nrf2-knockout mice and ferroptosis inhibitor (Ferrostatin-1) to investigate the potential roles of Nrf2 on seawater drowning-induced ALI and the underlying mechanisms. RESULTS: Our data shows that Nrf2 activator dimethyl fumarate could increase cell viability, reduced the levels of intracellular ROS and lipid ROS, prevented glutathione depletion and lipid peroxide accumulation, increased FTH1 and GPX4 mRNA expression, and maintained mitochondrial membrane potential in MLE-12 cells. However, ML385 promoted cell death and lipid ROS production in MLE-12 cells. Furthermore, the lung injury became more aggravated in the Nrf2-knockout mice than that in WT mice after seawater drowning. CONCLUSIONS: These results suggested that Nrf2 can inhibit ferroptosis and therefore alleviate ALI induced by seawater drowning. The effectiveness of ferroptosis inhibition by Nrf2 provides a novel therapeutic target for seawater drowning-induced ALI.

Sodium Propionate Attenuates the Lipopolysaccharide-Induced Epithelial-Mesenchymal Transition via the PI3K/Akt/mTOR Signaling Pathway.

Short-chain fatty acids (SCFAs), especially propionate, originate from the fermentation of dietary fiber in the gut and play a key role in inhibiting pulmonary inflammation. Chronic inflammation may induce an epithelial-mesenchymal transition (EMT) in alveolar epithelial cells and result in fibrotic disorders. This study was designed to investigate the beneficial effect of sodium propionate (SP) on lipopolysaccharide (LPS)-induced EMT. In cultured BEAS-2B cells, the protein expression levels of E-cadherin, α-smooth muscle actin (SMA), and vimentin were 0.66 ± 0.20, 1.44 ± 0.23, and 1.32 ± 0.21 in the LPS group vs 1.11 ± 0.36 (P < 0.05), 1.04 ± 0.30 (P < 0.05), and 0.96 ± 0.13 (P < 0.01) in the LPS + SP group (mean ± standard deviation), respectively. Meanwhile, LPS-triggered inflammatory cytokines and extracellular proteins were also reduced by SP administration in BEAS-2B cells. Moreover, SP treatment attenuated inflammation, EMT, extracellular matrix (ECM) deposition, and even fibrosis in a mouse EMT model. In terms of mechanism, LPS-treated BEAS-2B cells exhibited a higher level of phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) phosphorylation, which was interrupted by SP treatment. It is worth noting that the blockade of the PI3K/Akt/mTOR signaling cascade reduced the LPS-evoked EMT process in BEAS-2B cells. These results suggest that SP can block LPS-induced EMT via inhibition of the PI3K/Akt/mTOR signaling cascade, which provides a basis for possible clinical use of SP in airway and lung diseases.

Hyperoside suppresses hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis.

BACKGROUND: Hypoxia is commonly existed in tumors and lead to cancer cell chemo/radio-resistance. It is well-recognized that tumor hypoxia is a major challenge for the treatment of various solid tumors. Hyperoside (quercetin-3-O-galactoside, Hy) possesses antioxidant effects and has been reported to protect against hypoxia/reoxygenation induced injury in cardiomyocytes. Therefore, Hy may be attractive compound applicable to hypoxia-related diseases. PURPOSE: This study was designed to determine the role of Hy in hypoxia-induced proliferation of non-small cell lung cancer cells and the underlying mechanism. STUDY DESIGN AND METHODS: A549, a human non-small cell lung cancer (NSCLC) cell line, was used in the present study. 1% O2 was used to mimic the in vivo hypoxic condition of NSCLC. The potential mechanisms of Hy on hypoxia-induced A549 survival and proliferation, as well as the involvement of AMPK/HO-1 pathway were studied via CCK-8 assay, EdU staining, flow cytometry, qRT-PCR and western blot. RESULTS: We showed that pretreatment with Hy suppressed hypoxia-induced A549 survival and proliferation in dose-dependent manner. In terms of mechanism, hypoxia-treated A549 showed the lower AMPK phosphorylation and the reduced HO-1 expression, which were reversed by Hy pretreatment. Both AMPK inhibitor (Compound C) and HO-1 activity inhibitor (Zinc protoporphyrin IX) abolished Hy-evoked A549 cell death under hypoxia stimuli. Of note, Ferrous iron contributed to Hy-induced A549 cell death under hypoxia, while Hy had no effect on lipid peroxidation under hypoxia. CONCLUSION: Taken together, our results highlighted the beneficial role of Hy against hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis.

Protostemonine alleviates heat-killed methicillin-resistant Staphylococcus aureus-induced acute lung injury through MAPK and NF-κB signaling pathways.

Acute lung injury (ALI) and its most severe form acute respiratory distress syndrome (ARDS) caused by gram-positive bacteria threatens human life because effective treatments and medicines is unavailable. Protostemonine (PSN), an active alkaloid mainly isolated from the roots of Stemona sesslifolia, has anti-inflammatory effects on asthma and gram-negative bacteria-induced ALI. Here, we found that PSN exhibits anti-inflammatory effects and alleviates heat-killed methicillin-resistant Staphylococcus aureus (HKMRSA)-induced pneumonia. PSN treatment significantly attenuated HKMRSA-induced pathological injury, pulmonary neutrophil infiltration, tissue permeability and the production of pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) in murine ALI model. In addition, PSN decreased the content of TNF-α, IL-1ß, IL-6 and the expression of iNOS, as well as the production of NO in HKMRSA-induced bone marrow derived macrophages (BMDMs). Furthermore, treatment with PSN suppressed the activation of MAPKs (e.g. p38 MAPK, JNK and ERK) and NF-κB. Collectively, our results suggest that PSN ameliorates gram-positive bacteria-induced ALI in mice by inhibition of the MAPK and NF-κB signaling pathways, and our studies suggest that PSN might be a novel candidate for treating ALI/ARDS.

Preparation and Properties of Cryogel Based on Poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate).

The immobilized metal affinity cryogels based on poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate) (p(HEMA-GMA)) containing hydroxy and epoxy groups were prepared by free-radical copolymerization under cryogenic condition and then functionalized with iminodiacetic acid and chelated Cu2+, Ca2+, and Fe3+ ions to the p(HEMA-GMA) cryogel. The structures of p(HEMA-GMA) and immobilized metal-affinity cryogels were analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy. SEM results showed that the prepared cryogels had interconnected pores with the size of 30-100 µm. The performance of water swelling into the cryogels was fitted in Fickian diffusion. The adsorption property of cryogels was influenced by the immobilized ionic type, temperature, and adsorbate. The adsorption capacity of immobilized Cu2+ cryogel (p(HEMA)-Cu2+ (0.5 M) cryogel) was the highest in comparison with that of Ca2+ and Fe3+ affinity cryogels under the same condition. The maximum adsorption capacity of p(HEMA)-Cu2+ (0.5 M) cryogel for porcine pancreatic lipase was 150.14 mg/g at a higher temperature of 35 °C, whereas for bovine serum albumin, the maximum adsorption capacity was 154.11 mg/g at a lower temperature of 25 °C. The research of thermodynamics and kinetics indicated that the mechanism of the protein adsorption process corresponded to the Langmuir model and pseudo-second-order model.

Preparation and properties of cryogel based on poly(hydroxypropyl methacrylate).

A novel supermacroporous poly(hydroxypropyl methacrylate) (p(HPMA)) cryogel was synthesized by cryogelation method at -16 °C. In this synthesis process, HPMA was used as a monomer, and N,N'-methylenebisacrylamide (MBAAm) was used as cross-linker; the reaction was carried out in the presence of redox initiator pair N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS). The effect of monomer concentration, cross-linker content, cooling rate, and dioxane co-solvent were determined with respect to the pore structure, mechanical behavior, swelling degree, and porosity of cryogel. The ESEM images indicate that the pore wall structure of cryogels was rough; moreover, small holes were present in the pore walls of cryogels. The result of compression test indicates that cryogels can be compressed by at least 80% without any breakdown. The result of swelling kinetics indicates that cryogels attain swelling equilibrium in 10 s. Furthermore, p(HPMA)-Cu2+ cryogel was prepared by loading Cu2+ ions on functionalized poly(hydroxypropyl methacrylate)-iminodiacetic acid (p(HPMA)-IDA) cryogel. We investigated the adsorption of bovine serum albumin (BSA) on cryogels. The results indicate that compared to Freundlich isotherm, Langmuir isotherm could more suitably describe the adsorption process of BSA on cryogels. Meanwhile, the adsorption capacity of p(HPMA)-Cu2+ cryogel was significantly greater than that of p(HPMA) cryogel. The maximum adsorption capacity of BSA on p(HPMA)-Cu2+ cryogel, which was treated with 1 M Cu2+ ions, was as high as 196.87 mg/g cryogel (equivalent to 20.48 mg/mL cryogel) at 25 °C and pH = 7.8; therefore, the maximum adsorption capacity of BSA on p(HPMA)-Cu2+ cryogel was 4.35 times higher than that of p(HPMA) cryogel. Thus, the adsorption capacity of cryogels was strongly influenced by Cu2+ concentration, moreover, temperature changes clearly affected the adsorption capacity of p(HPMA)-Cu2+cryogel. The adsorption capacity at 25 °C was twice as that at 15 °C. By calculating Gibbs free energy change (∆G) of adsorption, we found that the adsorption process was spontaneous; moreover, adsorption process occurred better at higher temperature.