Gamma-oryzanol reduces renal inflammation and oxidative stress by modulating AGEs/RAGE axis in animals submitted to high sugar-fat diet

The AGEs/RAGE Signaling Pathway Regulates NLRP3-Mediated Neuronal Pyroptosis After MCAO Injury in Lepr-/- Obese Rats

Background

Obesity is recognized as a primary risk factor for cerebral ischemia, which has shown a significant increase in its incidence among obese patients. The exact mechanism by which obesity exacerbates cerebral ischemic injury is not fully understood though. The present study validated the hypothesis that obesity mediates pyroptosis by the AGEs/RAGE signaling pathway to exacerbate cerebral ischemic injury.

Methods

Leptin receptor knockout (Lepr-/- ) rats were used in this study to construct an obesity model, and the middle cerebral artery occlusion (MCAO) models of ischemic stroke were established in Lepr-/- obese rats and their wild-type (WT) littermates respectively. Zea-Longa score, TTC and H&E staining were utilized to evaluate the neurological impairment. Western Blot, immunohistochemistry, and immunofluorescence were used to detect protein expressions. Transmission electron microscopy was used to observe the pores in the neuronal cell membrane in the ischemic penumbra cortex.

Results

Compared with WT littermates, Lepr-/- obese rats exhibited exacerbated neuronal injury after MCAO, with higher expressions of NLRP3 inflammasome and pyroptosis-related proteins in the cortical tissue of the penumbra. Moreover, more GSDMD pores were observed on the neuronal cell membranes of Lepr-/- obese rats according to the electron microscopy. Inhibition of NLRP3 inflammasome expression with MCC950 inhibited neuronal pyroptosis after cerebral ischemia in Lepr-/- obese rats, thus reducing neuronal injury. We also found that compared with WT littermates, the levels of AGEs and RAGE in the cortex of Lepr-/- obese rats are significantly higher, with further increase after cerebral ischemia. Inhibition of AGEs/RAGE signaling pathway with FPS-ZM1 reduced the NLRP3 inflammasome-mediated neuronal pyroptosis in Lepr-/- obese rats, thereby mitigating the neuronal damage after cerebral ischemia.

Conclusion

The AGEs/RAGE signaling pathway is involved in the exacerbation of cerebral ischemic injury in Lepr-/- obese rats via regulating NLRP3-mediated neuronal pyroptosis.

Activation and modulation of the AGEs-RAGE axis: Implications for inflammatory pathologies and therapeutic interventions - A review

Chronic inflammation is a common foundation for the development of many non-communicable diseases, particularly diabetes, atherosclerosis, and tumors. The activation of the axis involving Advanced Glycation End products (AGEs) and their receptor RAGE is a key promotive factor in the chronic inflammation process, influencing the pathological progression of these diseases. The accumulation of AGEs in the body results from an increase in glycation reactions and oxidative stress, especially pronounced in individuals with diabetes. By binding to RAGE, AGEs activate signaling pathways such as NF-κB, promoting the release of inflammatory factors, exacerbating cell damage and inflammation, and further advancing the formation of atherosclerotic plaques and tumor development. This review will delve into the molecular mechanisms by which the AGEs-RAGE axis activates chronic inflammation in the aforementioned diseases, as well as strategies to inhibit the AGEs-RAGE axis, aiming to slow or halt the progression of chronic inflammation and related diseases. This includes the development of AGEs inhibitors, RAGE antagonists, and interventions targeting upstream and downstream signaling pathways. Additionally, the early detection of AGEs levels and RAGE expression as biomarkers provides new avenues for the prevention and treatment of diabetes, atherosclerosis, and tumors.

Bajitianwan formula extract ameliorates bone loss induced by iron overload via activating RAGE/PI3K/AKT pathway based on network pharmacology and transcriptomic analysis

Osteoporosis (OP) is closely related to iron overload. Bajitianwan (BJTW) is a traditional Chinese medicine formulation used for treating senile diseases such as dementia and osteoporosis. Modern pharmacological researches have found that BJTW has beneficial effect on bone loss and memory impairment in aging rats. This paper aimed to explore the role and mechanism of BJTW in ameliorating iron overload-induced bone loss. Furthermore, BJTW effectively improved the bone micro-structure of the femur in mice, and altered bone metabolism biomarkers alkaline phosphatase (ALP) and osteocalcin (OCN) in serum, as well as oxidative indexes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) glutathione (GSH) and malondialdehyde (MDA) in liver. As for network pharmacology, 73 components collected from BJTW regulated 99 common targets merged in the BJTW and OP. The results of RNA-seq indicated that there were 418 potential targets in BJTW low dose group (BJTW-L) and 347 potential targets in BJTW high dose group (BJTW-H). Intriguingly, both PI3K-AKT signaling pathway and the AGEs-RAGE signaling pathway were contained in the KEGG pathways enrichment results of network pharmacology and transcriptomics, which were considered as the potential mechanism. Additionally, we verified that BJTW regulated the expression of related proteins in RAGE/PI3K-AKT pathways in MC3T3-E1 cells. In summary, BJTW has potent effect on protecting against iron overload-induced OP, and its mechanism may be related to the activation of the RAGE/PI3K-AKT signaling pathways.

Antioxidants Supplementation During Exercise: Friends or Enemies for Cardiovascular Homeostasis?

Exercise is a preferred strategy for improving cardiac function, especially for patients with cardiovascular diseases. Increasing evidence indicates that oxidative stress is involved in exercise-induced cardioprotection, while the underlying mechanism remains unclear. Furthermore, the effect of antioxidant supplementation during or post-exercise still exists despite divergences. To explore the effect of oxidative stress and antioxidant supplementation on cardiovascular homeostasis during or post-exercise, we take insights into the progress of exercise-induced oxidative stress, antioxidant supplementation, and cardiovascular homeostasis. In particular, antioxidants such as vitamin C or E, gamma-oryzanol, and other natural antioxidants are discussed concerning regulating exercise-associated oxidative stress. Additionally, our present study reviewed and discussed a meta-analysis of antioxidant supplementation during exercise. Overall, we take an insight into the essential biological adaptations in response to exercise and the effects of antioxidant supplementation on cardiac function, which aid us in giving recommendations on antioxidant supplementation for exercisers and exercised people. A better understanding of these issues will broaden our knowledge of exercise physiology.

Bergamot (Citrus bergamia) leaf extract improves metabolic, antioxidant and anti-inflammatory activity in skeletal muscles in a metabolic syndrome experimental model

Metabolic Syndrome (MetS), inflammation and oxidative stress contribute to impairment of skeletal muscle function. Bergamot (Citrus bergamia) leaf extract (BLE) has shown protective effects against comorbidities associated with MetS through its anti-inflammatory and antioxidant effects. The aim of this work was to elucidate the antioxidant and anti-inflammatory activity of BLE in skeletal muscles in an experimental model of MetS. Once metabolic syndrome was diagnosed, animals were divided into groups receiving different treatments for 10 weeks, including control diet (n = 10), control + BLE (n = 10), High Sugar-fat diet (HSF) (n = 10), HSF + BLE (n = 10). Evaluation included nutritional, metabolic and hormonal analyses, along with measurements of inflammatory status and oxidative stress in soleus and extensor digitorum longus (EDL) muscles. BLE showed positive metabolic effects, with a reduction of plasma triglycerides and insulin resistance and an increase in high-density lipoprotein cholesterol, and protective activity against oxidative stress and inflammation in Soleus and EDL muscles in animals with MetS.