Momordica charantia polysaccharide ameliorates D-galactose-induced aging through the Nrf2/ß-Catenin signaling pathway.

Aging is widely thought to be associated with oxidative stress. Momordica charantia (MC) is a classic vegetable and traditional herbal medicine widely consumed in Asia, and M. charantia polysaccharide (MCP) is the main bioactive ingredient of MC. We previously reported an antioxidative and neuroprotective effect of MCP in models of cerebral ischemia/reperfusion and hemorrhage injury. However, the role played by MCP in neurodegenerative diseases, especially during aging, remains unknown. In this study, we investigated the protective effect of MCP against oxidative stress and brain damage in a D-galactose-induced aging model (DGAM). The Morris water maze test was performed to evaluate the spatial memory function of model rats. The levels of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were measured and telomerase activity was determined. The results showed that MCP treatment attenuated spatial memory dysfunction induced by D-galactose. In addition, MCP increased antioxidant capacity by decreasing MDA and increasing SOD and GSH levels. MCP treatment also improved telomerase activity in aging rats. Mechanistically, MCP promoted the entry of both Nrf2 and ß-Catenin into the nucleus, which is the hallmark of antioxidation signaling pathway activation. This study highlights a role played by MCP in ameliorating aging-induced oxidative stress injury and reversing the decline in learning and memory capacity. Our work provides evidence that MCP administration might be a potential antiaging strategy.

Astragaloside IV attenuates sepsis-induced intestinal barrier dysfunction via suppressing RhoA/NLRP3 inflammasome signaling.

Intestinal barrier dysfunction is a trigger for sepsis progression. NLRP3 inflammasome and RhoA contribute to sepsis and intestinal inflammation. The current study aimed to explore the effects of Astragaloside IV (AS-IV), a bioactive compound from Astragalus membranaceus, on sepsis-caused intestinal barrier dysfunction and whether NLRP3 inflammasome and RhoA are involved. Septic mice modeled by cecal ligation and puncture (CLP) operation were administered with 3 mg/kg AS-IV intravenously. AS-IV decreased mortality, cytokines release, I-FABP secretion, intestinal histological score and barrier permeability, and increased tight junction (TJ) expression in intestine in CLP model. Also, in Caco-2 cells subjected to lipopolysaccharide (LPS), 200 µg/mL AS-IV co-incubation reduced cytokines levels and enhanced in vitro gut barrier function without cytotoxicity. Subsequently, NLRP3 inflammasome and RhoA were highly activated both in intestinal tissue in vivo and in Caco-2 cells in vitro, both of which were significantly suppressed by AS-IV treatment. In addition, the benefits of AS-IV on Caco-2 monolayer barrier were largely counteracted by RhoA agonist CN03 and NLRP3 gene overexpression, respectively. Furthermore, LPS-induced NLRP3 inflammasome activation was abrogated by RhoA inhibitor C3 exoenzyme. However, NLRP3 knockdown by siRNA hardly affected RhoA activation in Caco-2 cells. These data suggest that AS-IV protects intestinal epithelium from sepsis-induced barrier dysfunction via inhibiting RhoA/NLRP3 inflammasome signal pathway.

ox-LDL increases microRNA-29a transcription through upregulating YY1 and STAT1 in macrophages.

Macrophages and oxidized low-density lipoprotein (ox-LDL) have been verified playing vital roles in the pathogenesis of atherosclerosis (AS). Previous studies demonstrated that microRNA-29a (miR-29a) was upregulated in many atherogenic process and cells, thus acting as an important participant in AS. But the detailed regulation mechanism of miR-29a in AS has not been fully understood. In our study, we demonstrated a positive feedback loop of ox-LDL-SRA-miR-29a. Furthermore, we found that YY1 and STAT1 were upregulated in ox-LDL-stimulating macrophages followed by translocation in the nucleus and binding to the transcriptional promoter region of miR-29a, thus leading to the increase of miR-29a expression. In addition, we demonstrated that JAK1/2 signaling was involved in miR-29a upregulation. Finally, we found that miR-29a played important roles in the secretion of proinflammation factors and lipid uptake in macrophages. We uncovered the molecular mechanism and provide novel insights into the function and regulatory network of miR-29a expression regulated by ox-LDL in macrophages.

Depression can be prevented by astaxanthin through inhibition of hippocampal inflammation in diabetic mice.

The critical factor considered in a depression induced by diabetes is the inflammation eliciting hippocampal, amygdala and thalamic neuronal injury. Therefore, inhibiting inflammatory reactions in the brain and reducing neuronal injury can alleviate depression in rodents suffering from diabetes mellitus. The oral administration of astaxanthin has been employed in emotional disorders and diabetic complications due to its anti-depressant, anti-inflammatory and anti-apoptotic functions. However, it has not been reported whether astaxanthin can improve diabetes-related depression-like behavior, and its potential mechanisms have not been elucidated. The objective of the present study is to elucidate the effect of astaxanthin on depression in diabetic mice and to understand the underlying molecular mechanisms. In this study, experimental diabetic mice were given a single intraperitoneal injection of streptozotocin (STZ, 150mg/kg, dissolved in citrate buffer) after fasting for 12h. The diabetic model was assessed 72h after STZ injection, and mice with a fasting blood glucose level more than or equal to 16.7mmol/L were used in this study, and oral astaxanthin (25mg/kg) was provided uninterrupted for ten weeks. Depression-like behavior was evaluated by the tail suspension test (TST) and forced swimming test (FST). The glial fibrillary acidic protein (GFAP) and cleaved caspase-3-positive cells were measured by immunohistochemistry, and the western blotting was used to test the protein levels of interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and cyclooxygenase (COX-2). The results showed that astaxanthin had an anti-depressant effect on diabetic mice. Furthermore, we observed that astaxanthin significantly reduced the number of GFAP-positive cells in the hippocampus and hypothalamus, and also the expression of cleaved caspase-3 in the hippocampus, amygdala and hypothalamus was decreased as well. Moreover, astaxanthin could down-regulate the expression of IL-6, IL-1ß and COX-2 in the hippocampus. These findings suggest that the mechanism of astaxanthin in preventing depression in diabetic mice involves the inhibition of inflammation/inflammation inhibition, thereby protecting neurons in hippocampus, amygdala and hypothalamus against hyperglycemic damage.

Inhibition of inflammation by astaxanthin alleviates cognition deficits in diabetic mice.

Neurons in the hippocampal and cortical functional regions are more susceptible to damage induced by hyperglycemia, which can result in severe spatial learning and memory impairment. Neuroprotection ameliorates cognitive impairment induced by hyperglycemia in diabetic encephalopathy (DE). Astaxanthin has been widely studied in diabetes mellitus and diabetic complications due to its hypoglycemic, antioxidant and anti-apoptotic effects. However, whether astaxanthin can alleviate cognition deficits induced by DE and its precise mechanisms remain undetermined. In this study, DE was induced by streptozotocin (STZ, 150 mg/kg) in ICR mice. We observed the effect of astaxanthin on cognition and investigated its potential mechanisms in DE mice. Results showed that astaxanthin treatment significantly decreased the latency and enhanced the distance and time spent in the target quadrant in the Morris water maze test. Furthermore, neuronal survival was significantly increased in the hippocampal CA3 region and the frontal cortex following treatment with astaxanthin. Meanwhile, immunoblotting was used to observe the nuclear translocation of nuclear factor-kappaB (NF-κB) p65 and the expression of tumor necrosis factor-α (TNF-α) in the hippocampus and frontal cortex. The results indicated that astaxanthin could inhibit NF-κB nuclear translocation and downregulate TNF-α expression in the hippocampus and frontal cortex. Overall, the present study implied that astaxanthin could improve cognition by protecting neurons against inflammation injury potentially through inhibiting the nuclear translocation of NF-κB and down-regulating TNF-α.