scholarly journals Lipin1 Alleviates Autophagy Disorder in Sciatic Nerve and Improves Diabetic Peripheral Neuropathy

Author(s):  
Meijian Wang ◽  
Min Xie ◽  
Shuyan Yu ◽  
Pan Shang ◽  
Cong Zhang ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Chunyang Xu ◽  
Biyu Hou ◽  
Ping He ◽  
Peng Ma ◽  
Xinyu Yang ◽  
...  

Oxidative stress has been recognized as the contributor to diabetic peripheral neuropathy (DPN). Antioxidant strategies have been most widely explored; nevertheless, whether antioxidants alone prevent DPN still remains inconclusive. In the present study, we established an in vitro DPN cell model for drug screening using Schwann RSC96 cells under high glucose (HG) stimulation, and we found that salvianolic acid A (SalA) mitigated HG-induced injury evidenced by cell viability and myelination. Mechanistically, SalA exhibited strong antioxidative effects by inhibiting 1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing reactive oxygen species (ROS), malondialdehyde (MDA), and oxidized glutathione (GSSG) content, as well as upregulating antioxidative enzyme mRNA expression. In addition, SalA significantly extenuated neuroinflammation with downregulated inflammatory factor mRNA expression. Furthermore, SalA improved the mitochondrial function of HG-injured Schwann cells by scavenging mitochondrial ROS, decreasing mitochondrial membrane potential (MMP), and enhancing ATP production, as well as upregulating oxidative phosphorylation gene expression. More importantly, we identified nuclear factor-E2-related factor 2 (Nrf2) as the upstream regulator which mediated protective effects of SalA on DPN. SalA directly bound to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) and thus disrupted the interaction of Nrf2 and Keap1 predicted by LibDock of Discovery Studio. Additionally, SalA significantly inhibited Nrf2 promoter activity and downregulated Nrf2 mRNA expression but without affecting Nrf2 protein expression. Interestingly, SalA upregulated the nuclear Nrf2 expression and promoted Nrf2 nuclear translocation by high content screening assay, which was confirmed to be involved in its antiglucotoxicity effect by the knockdown of Nrf2 in RSC96 cells. In KK-Ay mice, we demonstrated that SalA could effectively improve the abnormal glucose and lipid metabolism and significantly protect against DPN by increasing the mechanical withdrawal threshold and sciatic nerve conduction velocity and restoring the ultrastructural impairment of the injured sciatic nerve induced by diabetes. Hence, SalA protected against DPN by antioxidative stress, attenuating neuroinflammation, and improving mitochondrial function via Nrf2. SalA may be prospective therapeutics for treating DPN.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-Yin Zhou ◽  
Shi-Wen Zhou

The mechanisms leading to diabetic peripheral neuropathy are complex and there is no effective drug to treat it. As an active component of several traditional Chinese medicines, trigonelline has beneficial effects on diabetes with hyperlipidemia. The protective effects and the mechanism of trigonelline on diabetic peripheral neuropathy were evaluated in streptozotocin- and high-carbohydrate/high-fat diet-induced diabetic rats. Rats were divided into four groups at the end of week 2: control, diabetes, diabetes + trigonelline (40 mg/kg), and diabetes + sitagliptin (4 mg/kg). After 48-week treatment, technologies of nerve conduction, cold and hot immersion test, transmission electron microscopy, real-time PCR, and Western blotting were applied. Serum glucose, serum insulin, insulin sensitivity index, lipid parameters, body weight, sciatic nerve conduction velocity, nociception, glucagon-like peptide-1 receptor mRNA and protein, total and phosphorylated p38 mitogen-activated protein kinases protein expression, malonaldehyde content, and superoxide dismutase activity were altered in diabetic rats, and were near control levels treated with trigonelline. Slight micropathological changes existed in sciatic nerve of trigonelline-treated diabetic rats. These findings suggest that trigonelline has beneficial effects for diabetic peripheral neuropathy through glucagon-like peptide-1 receptor/p38 mitogen-activated protein kinases signaling pathway, nerve conduction velocity, antioxidant enzyme activity, improving micropathological changes of sciatic nerve and decreasing lipid peroxidation.


2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Chengcheng Feng ◽  
Lijuan Xu ◽  
Shiyun Guo ◽  
Qian Chen ◽  
Yuguo Shen ◽  
...  

WenTong HuoXue Cream (WTHX-Cream) has been shown to effectively alleviate clinical symptoms of diabetic peripheral neuropathy (DPN). This study investigated the gene and protein expression of the pain-related molecule PLC-β3 in the dorsal root ganglion (DRG) of DPN rats. 88 specific pathogen-free male Wistar rats were randomly divided into placebo (10 rats) and DPN model (78 rats) groups, and the 78 model rats were used to establish the DPN model by intraperitoneal injection of streptozotocin and were then fed a high-fat diet for 8 weeks. These rats were randomly divided into the model group, the high-, medium-, and low-dose WTHX-Cream + metformin groups, the metformin group, the capsaicin cream group, and the capsaicin cream + metformin group. After 4 weeks of continuous drug administration, the blood glucose, body weight, behavioral indexes, and sciatic nerve conduction velocity were measured. The pathological structure of the DRG and the sciatic nerve were observed. PLC-β3 mRNA and protein levels in the DRG of rats were measured. Compared with the model group, the high-dose WTHX-Cream group showed increased sciatic nerve conduction velocity, improved sciatic nerve morphological changes, and increased expression of PLC-β3 mRNA and protein in the DRG. This study showed that WTHX-Cream improves hyperalgesia symptoms of DPN by inhibiting the reduction of PLC-β3 mRNA and protein expression in the diabetic DRG of DPN rats.


2021 ◽  
Author(s):  
Meijian Wang ◽  
Min Xie ◽  
Shuyan Yu ◽  
Pan Shang ◽  
Cong Zhang ◽  
...  

Abstract Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes, and its exact pathogenesis remains unclear. Autophagy plays an important role in neurodegenerative diseases, ischemia–reperfusion injury of nerve tissues, and nerve tissue injury repair. Lipin1 is a phosphatidic acid phosphatase enzyme that converts phosphatidic acid (PA) into diacylglycerol (DAG), a precursor of triacylglycerol and phospholipids which plays an important role in maintaining normal peripheral nerve conduction function. Here, we show that induction of DPN rat model via STZ injection could reduce Lipin1 expression, prevent DAG synthesis, and results in autophagic hyperactivity. Interestingly, these effects increase the apoptosis of Schwann cells and lead to demyelination in sciatic nerve in DPN rats. More importantly, upregulation of lipin1 in the DPN rats ameliorated autophagy disorders and pathological changes of the sciatic nerve, which associated with the increase of the motor nerve conductive velocity (MNCV) in DPN rats. In contrast, lipin1 downregulation exacerbates neuronal abnormalities and facilitates the genesis of DPN phenotypes in rats. In addition, overexpression of lipin1 in RSC96 cells also significantly decreased the autophagic hyperactivity and apoptosis induced by hyperglycemia. These results suggest that lipin1 may exert neuroprotection within the sciatic nerve anomalies and may serve as a potential therapeutic target for the treatment of DPN.


2016 ◽  
Vol 11 (1) ◽  
pp. 156 ◽  
Author(s):  
Fei-yong Jia ◽  
Han-yu Dong ◽  
Xin-mei Jiang ◽  
Chun-bo Niu ◽  
Lin Du ◽  
...  

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