Metformin inhibits LPS-induced inflammatory response in VSMCs by regulating TLR4 and PPAR-γ

A novel sprayable thermosensitive hydrogel coupled with zinc modified metformin promotes the healing of skin wound

A novel sprayable adhesive is established (ZnMet-PF127) by the combination of a thermosensitive hydrogel (Pluronic F127, PF127) and a coordination complex of zinc and metformin (ZnMet). Here we demonstrate that ZnMet-PF127 potently promotes the healing of traumatic skin defect and burn skin injury by promoting cell proliferation, angiogenesis, collagen formation. Furthermore, we find that ZnMet could inhibit reactive oxygen species (ROS) production through activation of autophagy, thereby protecting cell from oxidative stress induced damage and promoting healing of skin wound. ZnMet complex exerts better effects on promoting skin wound healing than ZnCl₂ or metformin alone. ZnMet complex also displays excellent antibacterial activity against Staphylococcus aureus or Escherichia coli, which could reduce the incidence of skin wound infections. Collectively, we demonstrate that sprayable PF127 could be used as a new drug delivery system for treatment of skin injury. The advantages of this sprayable system are obvious: (1) It is convenient to use; (2) The hydrogel can cover irregular skin defect sites evenly in a liquid state. In combination with this system, we establish a novel sprayable adhesive (ZnMet-PF127) and demonstrate that it is a potential clinical treatment for traumatic skin defect and burn skin injury.

Curcumin alleviates lipopolysaccharides-induced inflammation and apoptosis in vascular smooth muscle cells via inhibition of the NF-κB and JNK signaling pathways

Curcumin plays an important role in inflammation regulation. This study aimed to investigate the effect of curcumin on vascular smooth muscle cells (VSMCs) inflammation induced by lipopolysaccharide (LPS) and its mechanism. VSMCs were treated with different concentrations of curcumin (0, 50, 100 and 150 μg/mL). MTT assay and flow cytometry were used to analyze the effects of curcumin on LPS-induced VSMCs viability and apoptosis. The expression and release of inflammatory cytokines in VSMCs were detected by real-time quantitative polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Moreover, the proteins expressions of NF-κB and JNK signaling pathways were analyzed by western blot. Interestingly, the results showed that curcumin could reduce LPS induced inflammatory injury by increasing VSMC's viability, reducing apoptosis and inhibiting the release of inflammatory cytokines. In addition, curcumin increased the expression of Toll-like receptor 4 (TLR4) in LPS treated VSMCs. Mechanistically, we found that curcumin attenuated LPS-induced cell damage in VSMCs via inhibition of NF-κB and the JNK signal pathway. Curcumin can protect VSMCs from LPS induced inflammatory damage, which may be related to the blocking of NF-κB and the JNK signaling pathway. Herewith, curcumin could be potential therapeutics for the treatment of atherosclerosis.

Metformin alleviates bevacizumab-induced vascular endothelial injury by up-regulating GDF15 and activating the PI3K/AKT/FOXO/PPARγ signaling pathway

Background

Previous studies have reported that the combination of metformin and bevacizumab exhibit favorable efficacy in the treatment of cancer patients, and metformin possesses effects on relieving vascular injury in multiple diseases. Nonetheless, the effect of metformin in alleviating bevacizumab-induced vascular injury remains unknown. Therefore, the present study aimed to investigate the impact of metformin on apoptosis, vascular endothelial injury marker expressions, and inflammation in human umbilical vein endothelial cells (HUVECs), as well as its possible molecular mechanism.

Methods

HUVECs were treated with bevacizumab, metformin or both, and subsequently treated with growth differentiation factor 15 (GDF15) overexpression plasmid, negative control (NC) plasmid, GDF15 small interfering ribonucleic acid (siRNA), NC siRNA, and the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, respectively. After treatment, apoptosis, levels of endothelial injury biomarkers and the potential downstream proteins were detected.

Results

Bevacizumab increased the levels of apoptosis, vascular endothelial injury marker expressions and pro-inflammatory cytokine expressions in HUVECs, while metformin alleviated these effects in bevacizumab-treated HUVECs. Furthermore, GDF15 overexpression reduced the apoptosis, vascular endothelial injury marker expressions, pro-inflammatory cytokine expressions, and activated the PI3K/protein kinase B (AKT)/forkhead box O (FOXO)/peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway in bevacizumab-treated HUVECs. Subsequently, GDF15 siRNA reduced the effects of metformin on the bevacizumab-induced vascular endothelial injury (as described above) in HUEVCs. Lastly, the PI3K inhibitor exhibited similar effects to those of GDF15 siRNA in bevacizumab-treated HUVECs.

Conclusions

Metformin protected against bevacizumab-induced vascular endothelial injury via activation of GDF15 and the PI3K/AKT/FOXO/PPARγ signaling pathway.

Isomer-Specific Effects of cis-9,trans-11- and trans-10,cis-12-CLA on Immune Regulation in Ruminal Epithelial Cells

Simple Summary

The significant contribution of rumen microbiota to the balance of the innate immunity of rumen epithelium has been extensively verified. As the natural rumen microbial metabolites, information regarding the immunoprotective effects of different conjugated linoleic acid (CLA) isomers on ruminal epithelial cells (RECs) is limited. In this study, the 100 μM trans-10,cis-12-CLA exerted better anti-inflammatory effects than the cis-9,trans-11-CLA by significantly downregulating the expression of genes related to inflammation, cell proliferation and migration in RECs upon lipopolysaccharide (LPS) stimulation. The trans-10,cis-12-CLA, but not cis-9,trans-11-CLA, significantly suppressed the biological signals of gene ontology (GO) terms’ response to lipopolysaccharide, the regulation of signal transduction and cytokine production and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways NF-κB, chemokine, NOD-like receptor, Hippo, PI3K-Akt, TGF-β and Rap1 signaling in RECs upon LPS stimulation. Furthermore, pretreatment with trans-10,cis-12-CLA significantly reduced the expression of lipogenic genes and the biosynthesis of the unsaturated fatty acid pathway in RECs compared with the LPS group, however, cis-9,trans-11-CLA exhibited the opposite results. These results suggest the distinct isomer differences of CLA in the regulation of inflammatory responses and adipocytokine signaling in RECs and will provide important references for determining their target use in the future.

Abstract

In this study, we used transcriptomics and qPCR to investigate the potential immunoprotective effects of different conjugated linoleic acid (CLA) isomers, the natural rumen microbial metabolites, on lipopolysaccharide (LPS)-induced inflammation of ruminal epithelial cells (RECs) in vitro. The results showed that 100 μM trans-10,cis-12-CLA exerted higher anti-inflammatory effects than cis-9,trans-11-CLA by significantly downregulating the expression of genes related to inflammation, cell proliferation and migration in RECs upon LPS stimulation. Transcriptomic analyses further indicated that pretreatment with trans-10,cis-12-CLA, but not cis-9,trans-11-CLA, significantly suppressed the biological signals of GO terms’ response to LPS, the regulation of signal transduction and cytokine production and KEGG pathways NF-κB, chemokine, NOD-like receptor, Hippo, PI3K-Akt, TGF-β and Rap1 signaling in RECs upon LPS stimulation. Furthermore, pretreatment with trans-10,cis-12-CLA significantly reduced the expression of lipogenic genes and the biosynthesis of the unsaturated fatty acid pathway in RECs compared with the LPS group, however, cis-9,trans-11-CLA exhibited the opposite results. These results suggest the distinct isomer differences of CLA in the regulation of inflammatory responses and adipocytokine signaling in RECs and will provide important references for determining their target use in the future.

Berberine ameliorates the LPS-induced imbalance of osteogenic and adipogenic differentiation in rat bone marrow-derived mesenchymal stem cells

Lipopolysaccharide (LPS) from oral pathogenic bacteria is an important factor leading to alveolar bone absorption and the implant failure. The present study aimed to evaluate the modulation of berberine hydrochloride (BBR) on the LPS-mediated osteogenesis and adipogenesis imbalance in rat bone marrow-derived mesenchymal stem cells (BMSCs). Cell viability, osteoblastic and adipogenic differentiation levels were measured using the Cell Counting Kit-8 assay, alkaline phosphatase (ALP) staining and content assay, and oil red O staining, respectively. Reverse transcription-quantitative PCR and immunoblotting were used to detect the related gene and protein expression levels. In undifferentiated cells, BBR increased the mRNA expression levels of the osteoblastic genes (Alp, RUNX family transcription factor 2, osteocalcin and secreted phosphoprotein 1) but not the adipogenic genes (fatty acid binding protein 4, Adipsin and peroxisome proliferator-activated receptorγ). LPS-induced osteoblastic gene downregulation, adipogenic gene enhancement and NF-κB activation were reversed by BBR treatment. In osteoblastic differentiated cells, decreased ALP production by LPS treatment was recovered with BBR co-incubation. In adipogenic differentiated cells, LPS-mediated lipid accumulation was decreased by BBR administration. The mRNA expression levels of the pro-inflammatory factors (MCP-1, TNF-α, IL-6 and IL-1β) were increased by LPS under both adipogenic and osteoblastic conditions, which were effectively ameliorated by BBR. The actions of BBR were attenuated by compound C, suggesting that the role of BBR may be partly due to AMP-activated protein kinase activation. The results demonstrated notable pro-osteogenic and anti-adipogenic actions of BBR in a LPS-stimulated inflammatory environment. This indicated a potential role of BBR for bacterial infected-related peri-implantitis medication.

Investigating the Vascular Toxicity Outcomes of the Irreversible Proteasome Inhibitor Carfilzomib

Background: Carfilzomib’s (Cfz) adverse events in myeloma patients include cardiovascular toxicity. Since carfilzomib’s vascular effects are elusive, we investigated the vascular outcomes of carfilzomib and metformin (Met) coadministration. Methods: Mice received: (i) saline; (ii) Cfz; (iii) Met; (iv) Cfz+Met for two consecutive (acute) or six alternate days (subacute protocol). Leucocyte-derived reactive oxygen species (ROS) and serum NO_x levels were determined and aortas underwent vascular and molecular analyses. Mechanistic experiments were recapitulated in aged mice who received similar treatment to young animals. Primary murine (prmVSMCs) and aged human aortic smooth muscle cells (HAoSMCs) underwent Cfz, Met and Cfz+Met treatment and viability, metabolic flux and p53-LC3-B expression were measured. Experiments were recapitulated in AngII, CoCl₂ and high-glucose stimulated HAoSMCs. Results: Acutely, carfilzomib alone led to vascular hypo-contraction and increased ROS release. Subacutely, carfilzomib increased ROS release without vascular manifestations. Cfz+Met increased PGF2α-vasoconstriction and LC3-B-dependent autophagy in both young and aged mice. In vitro, Cfz+Met led to cytotoxicity and autophagy, while Met and Cfz+Met shifted cellular metabolism. Conclusion: Carfilzomib induces a transient vascular impairment and oxidative burst. Cfz+Met increased vascular contractility and synergistically induced autophagy in all settings. Therefore, carfilzomib cannot be accredited for a permanent vascular dysfunction, while Cfz+Met exert vasoprotective potency.