An Algal Metabolite-Based PPAR-γ Agonist Displayed Anti-Inflammatory Effect via Inhibition of the NF-κB Pathway

Anti-tumor effects of telmisartan in glioma-astrocyte non-contact co-cultures: A critical role of astrocytic IL-6-mediated paracrine growth promotion

Telmisartan, an angiotensin II type 1 receptor (AT1R) blocker, exhibits broad anti-tumor activity. However, in vitro, anti-proliferative effects are shown at doses far beyond the therapeutic plasma concentration. Considering the role of tumor microenvironment in glioma progression, glioma-astrocyte co-cultures were employed to test the anti-tumor potential of low-dose telmisartan. When a high dose was required for a direct anti-proliferative effect on glioma cell lines, a low dose significantly inhibited glioma cell proliferation and migration in the co-culture system. Under co-culture conditions, upregulated IL-6 expression in astrocytes played a critical role in glioma progression. Silencing IL-6 in astrocytes or IL-6R in glioma cells reduced proliferation and migration. Telmisartan (5 μM) inhibited astrocytic IL-6 expression, and its anti-tumor effects were reversed by silencing IL-6 or IL-6R and inhibiting signal transducer and activator of transcription 3 (STAT3) activity in glioma cells. Moreover, the telmisartan-driven IL-6 downregulation was not imitated by losartan, an AT1R blocker with little capacity of peroxisome proliferator-activated receptor-gamma (PPARγ) activation, but was eliminated by a PPARγ antagonist, indicating that the anti-glioma effects of telmisartan rely on its PPARγ agonistic activity rather than AT1R blockade. This study highlights the importance of astrocytic IL-6-mediated paracrine signaling in glioma growth and the potential of telmisartan as an adjuvant therapy for patients with glioma, especially those with hypertension.

A Novel Peroxisome Proliferator-Activated Receptor Gamma/Nuclear Factor-Kappa B Activation Pathway is Involved in the Protective Effect of Adipose-Derived Mesenchymal Stem Cells Against Ischemia-Reperfusion Lung Injury

BACKGROUND

Adipose-derived stem cells (ADSCs) are well-recognized for their remarkable ability to suppress ischemia-reperfusion lung injury (IRLI). The primary objective of this investigation was to elucidate the underlying mechanism through which ADSCs exert protective effects against IRLI.

METHODS

A warm hilar occlusion model in C57BL6J mice was used. Hilar occlusion was achieved for 1 hour (ischemic), and after 1 hour the occlusion was released (reperfusion) to recover for 3 hours. RNA sequencing, the physiological function, pathway activation, and expression of inflammatory cytokines were evaluated.

RESULTS

Lung gas exchange and pulmonary edema were significantly improved in the IRLI/ADSCs group compared with the IRLI group. RNA sequencing results suggested that the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor-kappa B (NF-κB) pathway was involved in the effect of the ADSCs. Administration of a PPARγ antagonist in the IRLI/ADSC group resulted in the deterioration of the physiological function. Furthermore, the PPARγ protein expression level decreased, the NF-κB protein expression level increased, and inflammatory cytokine parameters from lung tissue and blood sample worsened in the PPARγ antagonist-administered group.

CONCLUSION

Administration of ADSCs exerted a significant protective effect against IRLI in mice, and the effect is attributed to the activation of the PPARγ/NF-κB pathway.

Purple Napiergrass (Pennisetum purpureum Schumach) Hot Water Extracts Ameliorate High-Fat Diet-Induced Obesity and Metabolic Disorders in Mice

Purple Pennisetum (Pennisetum purpureum Schumach), a hybrid between Taihucao No. 2 and the local wild species of purple Pennisetum, has dark red stems and leaves due to its anthocyanin content. This study explores the potential of purple napiergrass extracts (PNE) in alleviating obesity and metabolic disorders induced by a high-fat diet in mice, where 50% of the caloric content is derived from fat. Mice were orally administered low-dose or high-dose PNE alongside a high-fat diet. Experimental findings indicate that PNE attenuated weight gain, reduced liver, and adipose tissue weight, and lowered blood cholesterol, triglyceride, low-density lipoprotein, and blood sugar levels. Stained sections showed that PNE inhibited lipid accumulation and fat hypertrophy in the liver. Immunoblotting analysis suggested that PNE improved the inflammatory response associated with obesity, dyslipidemia, and hyperglycemia induced by a high-fat diet. Furthermore, PNE potentially functions as a PPAR-γ agonist, increasing the adiponectin (ADIPOQ) concentration and suppressing inflammatory factors, while elevating the anti-inflammatory factor interleukin-10 (IL-10) in the liver. PNE-treated mice showed enhanced activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and AMP-activated protein kinase (AMPK) pathways and increased fatty acid oxidation and liver lipolysis. In conclusion, this study elucidated the mechanisms underlying the anti-inflammatory, PI3K/Akt, and AMPK pathways in a high-fat diet-induced obesity model. These findings highlight the potential of PNE in reducing weight, inhibiting inflammation, and improving blood sugar and lipid levels, showing the potential for addressing obesity-related metabolic disorders in humans.

AEE alleviates ox-LDL-induced lipid accumulation and inflammation in macrophages

Atherosclerosis is a chronic immune inflammatory disease. Aspirin eugenol ester (AEE) is a novel safe and non-toxic compound with many pharmacological effects such as anti-inflammatory, anti-hyperlipidemic and anti-thrombotic action. In order to investigate the effect of AEE on the inhibition of aortic lipid plaque formation and macrophage-derived foam cell formation induced by oxidized low density lipoprotein (ox-LDL), in vivo atherosclerosis model by feeding ApoE-/- mice with a high-fat diet and foam cells formation in vitro model by ox-LDL-induced RAW264.7 macrophages were established. It was found that AEE decreased the levels of TC and LDL-C in serum, and the plaque formation area and lipid accumulation in the aortic intima of ApoE-/- mice. In vitro studies showed that AEE could prevent the uptake of ox-LDL and reduce the contents of TC and FC in cells. AEE enhanced the cholesterol efflux by increasing the expression of ABCA1, ABCG1 and PPARγ, which effectively alleviated excess cholesterol accumulated in the cells. Meanwhile, AEE also reduced the secretion and expression of inflammatory factors in the cells. In addition, AEE could reverse the action of PPARγ inhibitor T0070907 and/or ox-LDL. Therefore, AEE may become an effective candidate drug for the prevention of atherosclerosis.

Chronic exposure to low-level lipopolysaccharide dampens influenza-mediated inflammatory response via A20 and PPAR network

Influenza A virus (IAV) infection leads to severe inflammation, and while epithelial-driven inflammatory responses occur via activation of NF-κB, the factors that modulate inflammation, particularly the negative regulators are less well-defined. In this study we show that A20 is a crucial molecular switch that dampens IAV-induced inflammatory responses. Chronic exposure to low-dose LPS environment can restrict this excessive inflammation. The mechanisms that this environment provides to suppress inflammation remain elusive. Here, our evidences show that chronic exposure to low-dose LPS suppressed IAV infection or LPS stimulation-induced inflammation in vitro and in vivo. Chronic low-dose LPS environment increases A20 expression, which in turn positively regulates PPAR-α and -γ, thus dampens the NF-κB signaling pathway and NLRP3 inflammasome activation. Knockout of A20 abolished the inhibitory effect on inflammation. Thus, A20 and its induced PPAR-α and -γ play a key role in suppressing excessive inflammatory responses in the chronic low-dose LPS environment.

The Nutritional Properties, Chemical Compositions, and Functional Characteristics of the Aerial Parts of Adonis coerulea

The nutrition and active compounds from plants are very important to regulate the immunity of the body by improving the oxidant and inflammatory response. In this article, we aimed to investigate the nutritional profile and the phytochemical compositions of Adonis coerulea; the functional characteristics and its possible mechanism were studied. Results showed that the aerial parts of Adonis coerulea (ACAP) contained the abundant of proteins (16.15%) and the minerals (31.02.09 mg/100 g dried ACAP); promisingly, the content of essential amino acids (8.25%) and fatty acids (13,220.45 mg/100 g) also were obtained to regulate the immunity and prevent some chronic diseases. The methanol extract of ACAP played the anti-inflammatory activity via peroxisome proliferators-activated receptor (PPAR)-γ-mediated nuclear factor kappa B (NF-κB) pathway. Among the 18 identified compounds, linolenic acid from fatty acids and licochalcone A were active compounds by inhibiting nitric oxide (NO) production of RAW264.7 cells induced by lipopolysaccharide (LPS). The alleviation of inflammatory response results in the decrease of oxidative stress; ACAP showed the antioxidant activity by attenuating antioxidant enzymes, improving mitochondrial membrane potential and reactive oxygen species. These results highlight the potential of A. coerulea as a source of active ingredients in pharmaceutical industries.

Chemical constituents and anti-inflammatory activity of the total alkaloid extract from Melodinus cochinchinensis (Lour.) Merr. and its inhibition of the NF-κB and MAPK signaling pathways

BACKGROUND

Melodinus cochinchinensis (Lour.) Merr. is a medicinal plant, which is used as a folk medicine for treating meningitis and fractures. However, the anti-inflammatory activity of total alkaloid extract from M. cochinchinensis (MCTA) and its molecular mechanism are still not studied.

PURPOSE

The aim of this study is to investigate the main chemical constituents of MCTA and explore its anti-inflammatory potential in both in vitro and in vivo assessments.

METHODS

UHPLC-ESI-HRMS/MS was applied to analyze the chemical profiling. The anti-inflammatory efficacy of MCTA was evaluated on lipopolysaccharide (LPS) induced RAW 264.7 cells and two common inflammation models in mice. The production of pro-inflammatory mediator and cytokine was tested using the ELISA method. The pathological change was analyzed by histological assessment. The expression of NF-κB, MAPKs and PPAR-γ proteins was evaluated using western blot analysis.

RESULTS

A total of 21 monoterpenoid indole alkaloids (MIAs) were characterized by UHPLC-ESI-HRMS/MS. Aspidospermine- and quinolone-type alkaloids were found to be the major compounds. MCTA significantly decreased the production of NO, IL-1β, IL-6 and TNF-α in LPS-induced RAW 264.7 macrophages. MCTA significantly inhibited the phosphorylation of ERK1/2, JNK and p38 MAPK, suppressed the NF-κB transcriptional activation and improved the PPAR-γ expression. Moreover, the in vivo experiment exhibited that MCTA pretreatment markedly alleviated the xylene-induced ear edema and carrageenan-induced paw edema in mice and decreased the IL-1β, IL-6 and TNF-α expressions.

CONCLUSION

MCTA is rich in MIAs and exhibited a significant inhibitory effect on the production proinflammatory cytokines. The mechanism might be related to the inhibition of activation of NF-κB and MAPK pathways.

The role of peroxisome proliferator-activated receptors in healthy and diseased eyes

Peroxisome Proliferator-Activated Receptors (PPARs) are a family of nuclear receptors that play essential roles in modulating cell differentiation, inflammation, and metabolism. Three subtypes of PPARs are known: PPAR-alpha (PPARα), PPAR-gamma (PPARγ), and PPAR-beta/delta (PPARβ/δ). PPARα activation reduces lipid levels and regulates energy homeostasis, activation of PPARγ results in regulation of adipogenesis, and PPARβ/δ activation increases fatty acid metabolism and lipolysis. PPARs are linked to various diseases, including but not limited to diabetes, non-alcoholic fatty liver disease, glaucoma and atherosclerosis. In the past decade, numerous studies have assessed the functional properties of PPARs in the eye and key PPAR mechanisms have been discovered, particularly regarding the retina and cornea. PPARγ and PPARα are well established in their functions in ocular homeostasis regarding neuroprotection, neovascularization, and inflammation, whereas PPARβ/δ isoform function remains understudied. Naturally, studies on PPAR agonists and antagonists, associated with ocular pathology, have also gained traction with the development of PPAR synthetic ligands. Studies on PPARs has significantly influenced novel therapeutics for diabetic eye disease, ocular neuropathy, dry eye, and age-related macular degeneration (AMD). In this review, therapeutic potentials and implications will be highlighted, as well as reported adverse effects. Further investigations are necessary before any of the PPARs ligands can be utilized, in the clinics, to treat eye diseases. Future research on the prominent role of PPARs will help unravel the complex mechanisms involved in order to prevent and treat ocular diseases.

Peroxisome Proliferator-Activated Receptors as a Therapeutic Target in Asthma

The complexity of the pathogenetic mechanisms of the development of chronic inflammation in asthma determines its heterogeneity and insufficient treatment effectiveness. Nuclear transcription factors, which include peroxisome proliferator-activated receptors, that is, PPARs, play an important role in the regulation of initiation and resolution of the inflammatory process. The ability of PPARs to modulate not only lipid homeostasis but also the activity of the inflammatory response makes them an important pathogenetic target in asthma therapy. At present, special attention is focused on natural (polyunsaturated fatty acids (PUFAs), endocannabinoids, and eicosanoids) and synthetic (fibrates, thiazolidinediones) PPAR ligands and the study of signaling mechanisms involved in the implementation of their anti-inflammatory effects in asthma. This review summarizes current views on the structure and function of PPARs, as well as their participation in the pathogenesis of chronic inflammation in asthma. The potential use of PPAR ligands as therapeutic agents for treating asthma is under discussion.