Gasdermin D silencing alleviates airway inflammation and remodeling in an ovalbumin-induced asthmatic mouse model.

Emerging evidence demonstrates that pyroptosis has been implicated in the pathogenesis of asthma. Gasdermin D (GSDMD) is the pyroptosis executioner. The mechanism of GSDMD in asthma remains unclear. The aim of this study was to elucidate the potential role of GSDMD in asthmatic airway inflammation and remodeling. Immunofluorescence staining was conducted on airway epithelial tissues obtained from both asthma patients and healthy controls (HCs) to evaluate the expression level of N-GSDMD. ELISA was used to measure concentrations of cytokines (IL-1ß, IL-18, IL-17A, and IL-10) in serum samples collected from asthma patients and healthy individuals. We demonstrated that N-GSDMD, IL-18, and IL-1ß were significantly increased in samples with mild asthma compared with those from the controls. Then, wild type and Gsdmd-knockout (Gsdmd-/-) mice were used to establish asthma model. We performed histopathological staining, ELISA, and flow cytometry to explore the function of GSDMD in allergic airway inflammation and tissue remodeling in vivo. We observed that the expression of N-GSDMD, IL-18, and IL-1ß was enhanced in OVA-induced asthma mouse model. Gsdmd knockout resulted in attenuated IL-18, and IL-1ß production in both bronchoalveolar lavage fluid (BALF) and lung tissue in asthmatic mice. In addition, Gsdmd-/- mice exhibit a significant reduction in airway inflammation and remodeling, which might be associated with reduced Th17 inflammatory response and M2 polarization of macrophages. Further, we found that GSDMD knockout may improve asthmatic airway inflammation and remodeling through regulating macrophage adhesion, migration, and macrophage M2 polarization by targeting Notch signaling pathway. These findings demonstrate that GSDMD deficiency profoundly alleviates allergic inflammation and tissue remodeling. Therefore, GSDMD may serve as a potential therapeutic target against asthma.

Correction: Human astrocytes secrete IL-6 to promote glioma migration and invasion through upregulation of cytomembrane MMP14.

[This corrects the article DOI: 10.18632/oncotarget.11515.].

Pathogenesis of Abnormal Hepatic Lipid Metabolism Induced by Chronic Intermittent Hypoxia in Rats and the Therapeutic Effect of N-Acetylcysteine.

BACKGROUND The pathogenesis of chronic intermittent hypoxia (CIH)-induced abnormal hepatic lipid metabolism in rats remains unclear. Here, we investigated the therapeutic effect of N-acetylcysteine (NAC) on abnormal hepatic lipid metabolism. MATERIAL AND METHODS Rats were subjected to hypoxia and NAC treatment, and evaluated in terms of hepatic lipid metabolism, hepatocyte ultrastructure, oxidative stress in hepatocytes, expression of nuclear factor-kappa B (NF-κB) and inflammatory cytokines (IL-1ß, IL-6, and TNFα), serum lipoprotein lipase (LPL) levels, and blood lipids (triglycerides and cholesterol). RESULTS Compared to the normoxic control group, animals in the hypoxic model group showed significant body weight gain; abnormal hepatic lipid metabolism; lipid vacuolization; accumulation of lipid droplets; abundant autophagosomes and lysosomes; significant increases in oxidative stress, inflammation level, and blood lipid levels; and significantly reduced LPL levels. Compared to control animals, rats in the treatment group exhibited normal body weight gain, improved lipid metabolism, fewer lipid droplets, alleviated ultrastructural injuries, decreased oxidative stress and inflammation level, as well as elevated LPL and reduced blood lipid levels. CONCLUSIONS The harmful effects of CIH on rat liver are possibly associated with the reactive oxygen species (ROS)/NF-κB signaling pathway. NAC is capable of attenuating lipid metabolism alterations and abnormal body weight gain in the CIH rat model, via a possible mechanism related to inhibition of ROS/NF-κB signaling.

The combination of db-cAMP and ChABC with poly(propylene carbonate) microfibers promote axonal regenerative sprouting and functional recovery after spinal cord hemisection injury.

This study describes the use of poly(propylene carbonate) (PPC) electrospun microfibres impregnated with a combination of dibutyryl cyclic adenosine monophosphate (db-cAMP) and chondroitinase ABC (ChABC) in the treatment of right-side hemisected spinal cord injury (SCI). Release of db-cAMP and/or ChABC from the microfibres was assessed in vitro using high-performance liquid chromatography (HPLC). Drug-impregnated microfibres were implanted into the hemisected thoracic spinal cord of rats, and treatment was evaluated using functional recovery examinations and immunohistochemistry. Our results demonstrated that the microfibres containing db-cAMP and/or ChABC displayed a stable and prolonged release of each agent. Sustained delivery of db-cAMP and/or ChABC was found to promote axonal regenerative sprouting, functional recovery, and reduced glial scar formation when compared to untreated control animals. The combination of both db-cAMP and ChABC was determined to be more effective than using either drug alone in the treatment of SCI. These findings demonstrate the feasibility of using PPC electrospun microfibres for multi-drug combination therapy in SCI.

Human astrocytes secrete IL-6 to promote glioma migration and invasion through upregulation of cytomembrane MMP14.

The brain microenvironment has emerged as an important component in malignant progression of human glioma. However, astrocytes, the most abundant glial cells in the glioma microenvironment, have as yet a poorly defined role in the development of this disease, particularly with regard to invasion. Here, we co-cultured human astrocytes with human glioma cell lines, U251 and A172, in an in vitro transwell system in order to ascertain their influence on migration and invasion of gliomas. mRNA and protein expression assays were subsequently used to identify candidate proteins mediating this activity. Astrocytes significantly increased migration and invasion of both U251 and A172 cells in migration and invasion (plus matrigel) assays. Membrane type 1 matrix metalloproteinase (MMP14) originating from glioma cells was identified in qRT-PCR as the most highly up-regulated member of the MMP family of genes (~ 3 fold, p < 0.05) in this system. A cytokine array and ELISA were used to identify interleukin-6 (IL-6) as a highly increased factor in media collected from astrocytes, especially under co-culture conditions. IL-6 was also the key cytokine inducing cytomembrane MMP14 expression, the active form of MMP14, in glioma cells. Knockdown of MMP14 with siRNA led to decreased migration and invasion. Taken together, our results indicated that cytomembrane MMP14 was induced by IL-6 secreted from astrocytes, thereby enhancing the migration and invasion of glioma cells through activation of MMP2. Therefore, this IL-6 and MMP14 axis between astrocytes and glioma cells may become a potential target for treatment of glioma patients.

Local in vitro delivery of rapamycin from electrospun PEO/PDLLA nanofibers for glioblastoma treatment.

Rapamycin, a mammalian target of rapamycin inhibitor and anti-proliferative agent, is used to treat glioma and other malignancies, but its effectiveness is limited by the fact that it cannot be delivered in a targeted manner to the site of the tumor. To address this issue, we fabricated a mesh via electrospinning using two biodegradable materials, poly(lactic acid) (PLA) and polyethylene oxide (PEO) as a carrier for rapamycin delivery to the tumor. Nanofiber diameter decreased with increasing PLA concentration in the mixed solution. Scanning electron microscopy analysis revealed the smooth and uniform surface morphology of hybrid fibers. Fourier transform infrared spectroscopy analysis demonstrated that rapamycin was encapsulated in the polymer solution; encapsulation efficiency was high and stable over the range of drug concentrations from 0.5-2wt%. A correlation was observed between sustained release of the drug in vitro and cytotoxicity in cultured glioma cells. These results indicate that the PEO/poly(d,l-lactic acid) nanofiber mesh can be used as a targeted delivery system for rapamycin that can limit side effects and prevent locoregional recurrence following surgical resection of glioma.

Anti-Neoplastic Cytotoxicity of SN-38-Loaded PCL/Gelatin Electrospun Composite Nanofiber Scaffolds against Human Glioblastoma Cells In Vitro.

Electrospun poly(ε-caprolactone) (PCL)/gelatin (GT) scaffolds were developed to provide controlled release of 7-ethyl-10-hydroxy camptothecin (SN-38). Acetic acid was introduced to improve the miscibility of PCL and GT to produce a homogeneous nanofiber membrane mixture. The effect of SN-38 content in binary mixtures on processability, fiber morphology, water sorption, swelling, and drug release was investigated. Electrospun PCL/GT blend nonwoven fibers showed fiber surface roughness, decreased PCL crystallinity, and increased swelling with increasing drug content of 1, 2, and 4 wt %. Additionally, increasing the SN-38 concentration reduced the degradation rate of the GT. Furthermore, we hypothesize the existence of a drug content saturation point in the monoaxial fiber to explain the different drug release patterns of PG2 compared with those of PG1 and PG4. The matrix also showed good biodegradation and anti-tumor function. Our results demonstrate that SN-38-loaded PCL/GT fibers can be obtained by electrospinning. The SN-38-loaded fibers merit further evaluation as a means to potentially prevent locoregional recurrence following surgical tumor resection.

Sustained delivery of chondroitinase ABC by poly(propylene carbonate)-chitosan micron fibers promotes axon regeneration and functional recovery after spinal cord hemisection.

We describe the sustained delivery of chondroitinase ABC (ChABC) in the hemisected spinal cord using polypropylene carbonate (PPC) electrospun fibers with chitosan (CS) microspheres as a vehicle. PPC and ChABC-loaded CS microspheres were mixed with acetonitrile, and micron fibers were generated by electrospinning. ChABC release was assessed in vitro with high-performance liquid chromatography (HPLC) and revealed stabilized and prolonged release. Moreover, the released ChABC showed sustained activity. PPC-CS micron fibers with or without ChABC were then implanted into a hemisected thoracic spinal cord. In the following 4 weeks, we examined functional recovery and performed immunohistochemical analyses. We found that sustained delivery of ChABC promoted axon sprouting and functional recovery and reduced glial scarring; PPC-CS micron fibers without ChABC did not show these effects. The present findings suggest that PPC-CS micron fibers containing ChABC are a feasible option for spinal cord injury treatment. Furthermore, the system described here may be useful for local delivery of other therapeutic agents.

Sustained delivery of dbcAMP by poly(propylene carbonate) micron fibers promotes axonal regenerative sprouting and functional recovery after spinal cord hemisection.

This study describes the use of poly(propylene carbonate) (PPC) electrospun fibers as vehicle for the sustained delivery of dibutyryl cyclic adenosine monophosphate (dbcAMP) to the hemisected spinal cord. The dbcAMP and PPC were uniformly mixed with acetonitrile; then, electrospinning was used to generate micron fibers. The release of dbcAMP was assessed by ELISA in vitro. Our results showed that the encapsulation of dbcAMP in the fibers led to stable and prolonged release in vitro. The PPC micron fibers containing dbcAMP and the PPC micron fibers without dbcAMP were then implanted into the hemisected thoracic spinal cord, followed by testing of the functional recovery and immunohistochemistry. Compared with the control group, sustained delivery of dbcAMP promoted axonal regenerative sprouting and functional recovery and reduced glial scar formation, and the PPC micron fibers without dbcAMP did not have these effects. Our findings demonstrated the feasibility of using PPC electrospun fibers containing dbcAMP for spinal cord injury. The approach described here also will provide a platform for the potential delivery of other axon-growth-promoting or scar-inhibiting agents.