scholarly journals Apelin-13/APJ system attenuates early brain injury via suppression of endoplasmic reticulum stress-associated TXNIP/NLRP3 inflammasome activation and oxidative stress in a AMPK-dependent manner after subarachnoid hemorrhage in rats

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Weilin Xu ◽  
Tao Li ◽  
Liansheng Gao ◽  
Jingwei Zheng ◽  
Jun Yan ◽  
...  

Abstract Background Neuroinflammation and oxidative stress play important roles in early brain injury following subarachnoid hemorrhage (SAH). This study is the first to show that activation of apelin receptor (APJ) by apelin-13 could reduce endoplasmic reticulum (ER)-stress-associated inflammation and oxidative stress after SAH. Methods Apelin-13, apelin siRNA, APJ siRNA, and adenosine monophosphate-activated protein kinase (AMPK) inhibitor-dorsomorphin were used to investigate if the activation of APJ could provide neuroprotective effects after SAH. Brain water content, neurological functions, blood-brain barrier (BBB) integrity, and inflammatory molecules were evaluated at 24 h after SAH. Western blotting and immunofluorescence staining were applied to assess the expression of target proteins. Results The results showed that endogenous apelin, APJ, and p-AMPK levels were significantly increased and peaked in the brain 24 h after SAH. In addition, administration of exogenous apelin-13 significantly alleviated neurological functions, attenuated brain edema, preserved BBB integrity, and also improved long-term spatial learning and memory abilities after SAH. The underlying mechanism of the neuroprotective effects of apelin-13 is that it suppresses microglia activation, prevents ER stress from overactivation, and reduces the levels of thioredoxin-interacting protein (TXNIP), NOD-like receptor pyrin domain-containing 3 protein (NLRP3), Bip, cleaved caspase-1, IL-1β, TNFα, myeloperoxidase (MPO), and reactive oxygen species (ROS). Furthermore, the use of APJ siRNA and dorsomorphin abolished the neuroprotective effects of apelin-13 on neuroinflammation and oxidative stress. Conclusions Exogenous apelin-13 binding to APJ attenuates early brain injury by reducing ER stress-mediated oxidative stress and neuroinflammation, which is at least partly mediated by the AMPK/TXNIP/NLRP3 signaling pathway.

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4210
Author(s):  
Yan Zhou ◽  
Chunxiu Zhou ◽  
Xutao Zhang ◽  
Chi Teng Vong ◽  
Yitao Wang ◽  
...  

Coptisine is the major bioactive protoberberine alkaloid found in Rhizoma Coptidis. Coptisine reduces inflammatory responses and improves glucose tolerance; nevertheless, whether coptisine has vasoprotective effect in diabetes is not fully characterized. Conduit arteries including aortas and carotid arteries were obtained from male C57BL/6J mice for ex vivo treatment with risk factors (high glucose or tunicamycin) and coptisine. Some arterial rings were obtained from diabetic mice, which were induced by high-fat diet (45% kcal% fat) feeding for 6 weeks combined with a low-dose intraperitoneal injection of streptozotocin (120 mg/kg). Functional studies showed that coptisine protected endothelium-dependent relaxation in aortas against risk factors and from diabetic mice. Coptisine increased phosphorylations of AMPK and eNOS and downregulated the endoplasmic reticulum (ER) stress markers as determined by Western blotting. Coptisine elevates NO bioavailability and decreases reactive oxygen species level. The results indicate that coptisine improves vascular function in diabetes through suppression of ER stress and oxidative stress, implying the therapeutic potential of coptisine to treat diabetic vasculopathy.


Author(s):  
Sinan Xiong ◽  
Wee-Joo Chng ◽  
Jianbiao Zhou

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.


2017 ◽  
Vol 40 ◽  
pp. 157-162 ◽  
Author(s):  
Yuwei Han ◽  
Tingting Zhang ◽  
Jingyuan Su ◽  
Yuan Zhao ◽  
Chenchen ◽  
...  

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Takehiko Kujiraoka ◽  
Yasushi Satoh ◽  
Makoto Ayaori ◽  
Yasunaga Shiraishi ◽  
Yuko Arai-Nakaya ◽  
...  

Background Insulin signaling comprises 2 major cascades, the IRS/PI3K/Akt and Ras/Raf/MEK/ERK pathways. Many studies on the tissue-specific effects of the former pathway had been conducted, however, the role of the latter cascade in tissue-specific insulin resistance had not been investigated. High glucose/fatty acid toxicity, inflammation and oxidative stress, all of which are associated with insulin resistance, can activate ERK. Liver plays a central role of metabolism and hepatosteatosis (HST) is associated with vascular diseases. The aim of this study is to elucidate the role of hepatic ERK2 in HST, metabolic remodeling and endothelial dysfunction. Methods Serum biomarkers of vascular complications in human were compared between subjects with and without HST diagnosed by echography for regular medical checkup. Next, we created liver-specific ERK2 knockout mice (LE2KO) and fed them with a high-fat/high-sucrose diet (HFHSD) for 20 weeks. The histological analysis, the expression of hepatic sarco/endoplasmic reticulum (ER) Ca 2+ -ATPase 2 (SERCA2) and glucose-tolerance/insulin-sensitivity (GT/IS) were tested. Vascular superoxide production and endothelial function were evaluated with dihydroethidium staining and isometric tension measurement of aorta. Results The presence of HST significantly increased HOMA-IR, an indicator of insulin resistance or atherosclerotic index in human. HFHSD-fed LE2KO revealed a marked exacerbation in HST and metabolic remodeling represented by the impairment of GT/IS, elevated serum free fatty acid and hyperhomocysteinemia without changes in body weight, blood pressure and serum cholesterol/triglyceride levels. In the HFHSD-fed LE2KO, mRNA and protein expressions of hepatic SERCA2 were significantly decreased, which resulted in hepatic ER stress. Induction of vascular superoxide production and remarkable endothelial dysfunction were also observed in them. Conclusions Hepatic ERK2 revealed the suppression of hepatic ER stress and HST in vivo , which resulted in protection from vascular oxidative stress and endothelial dysfunction. HST with hepatic ER stress can be a prominent risk of vascular complications by metabolic remodeling and oxidative stress in obese-related diseases.


2014 ◽  
Vol 121 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Xiang-Sheng Zhang ◽  
Xin Zhang ◽  
Meng-Liang Zhou ◽  
Xiao-Ming Zhou ◽  
Ning Li ◽  
...  

Object Aneurysmal subarachnoid hemorrhage (SAH) causes devastating rates of mortality and morbidity. Accumulating studies indicate that early brain injury (EBI) greatly contributes to poor outcomes after SAH and that oxidative stress plays an important role in the development of EBI following SAH. Astaxanthin (ATX), one of the most common carotenoids, has a powerful antioxidative property. However, the potential role of ATX in protecting against EBI after SAH remains obscure. The goal of this study was to assess whether ATX can attenuate SAH-induced brain edema, blood-brain barrier permeability, neural cell death, and neurological deficits, and to elucidate whether the mechanisms of ATX against EBI are related to its powerful antioxidant property. Methods Two experimental SAH models were established, including a prechiasmatic cistern SAH model in rats and a one-hemorrhage SAH model in rabbits. Both intracerebroventricular injection and oral administration of ATX were evaluated in this experiment. Posttreatment assessments included neurological scores, body weight loss, brain edema, Evans blue extravasation, Western blot analysis, histopathological study, and biochemical estimation. Results It was observed that an ATX intracerebroventricular injection 30 minutes post-SAH could significantly attenuate EBI (including brain edema, blood-brain barrier disruption, neural cell apoptosis, and neurological dysfunction) after SAH in rats. Meanwhile, delayed treatment with ATX 3 hours post-SAH by oral administration was also neuroprotective in both rats and rabbits. In addition, the authors found that ATX treatment could prevent oxidative damage and upregulate the endogenous antioxidant levels in the rat cerebral cortex following SAH. Conclusions These results suggest that ATX administration could alleviate EBI after SAH, potentially through its powerful antioxidant property. The authors conclude that ATX might be a promising therapeutic agent for EBI following SAH.


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