Terpene glycoside component from Moutan Cortex ameliorates diabetic nephropathy by regulating endoplasmic reticulum stress-related inflammatory responses.
BACKGROUND
Multiple lines of evidences have suggested that endoplasmic reticulum (ER) stress-related inflammatory responses play a critical role in the pathogenesis of diabetic nephropathy (DN). Moutan Cortex (MC), the root bark of Paeonia suffruticosa Andr., is a well-known traditional Chinese medicine (TCM), which has been used clinically for treating inflammatory diseases in China. The findings from our previous research suggested that terpene glycoside (TG) component of MC possessed favorable anti-inflammatory properties in curing DN. However, the underlying mechanisms of MC-TG for treating DN are still unknown.


OBJECTIVE
To explore the role of ER stress-related inflammatory responses in the progression of DN, and to investigate the underlying protective mechanisms of MC-TG in kidney damage.


METHODS
DN rats and advanced glycation end-products (AGEs) induced HBZY-1 cell dysfunction were established to evaluate the protective effect of MC-TG on ameliorating renal injury. Evaluation of pathological lesions was performed by Masson staining and transmission electron microscopy (TEM). Interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), glucose regulated protein 78 (GRP78/Bip), as well as spliced X box binding protein 1(XBP-1(s)) levels in rat serum were detected by an enzyme-linked immunosorbent assay (ELISA). Furthermore, western blotting (WB) was applied to detect the protein expressions including IL-6, MCP-1, intercellular cell adhesion molecule-1 (ICAM-1), GRP78/Bip, XBP-1 (s), phosphorylated inositol-requiring enzyme-1α (p-IRE1α), cleaved activating transcription factor 6 (ATF6), phosphorylated PKR-like endoplasmic reticulum kinase (p-PERK), and phosphorylated nuclear factor κB p65 (p-NF-κB p65) in vivo and in vitro. Immunohistochemistry (IHC) was carried out to determine the phosphorylation of IRE1α and NF-κB p65 in kidney tissues.


RESULTS
Pretreatment with MC-TG could markedly improve renal insufficiency and pathologic changes. It could down-regulate ER stress-related factors GRP78/Bip, XBP-1(s) levels, and also reduce the pro-inflammatory molecules IL-6, MCP-1, and ICAM-1 expressions. Furthermore, a significant decrease in phosphorylation of IRE1α and NF-κB p65 by the treatment of MC-TG.


CONCLUSIONS
These findings indicated that MC-TG ameliorated ER stress-related inflammation in the pathogenesis of DN, wherein the protective mechanism might be associated with the inhibition of IRE1/NF-κB activation. Thus, MC-TG might be a potential therapeutic candidate for the prevention and treatment of DN.
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijng 100700, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China; Third School of Clinical Medical of Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210028, PR China.
Juan
J
Chen
School of Pharmacy, Anhui University of Chinese Medicine, Anhui, Hefei 230012, PR China.
Xue-Feng
XF
Hou
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China.
Gang
G
Wang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China.
Qing-Xiang
QX
Zhong
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China.
Ying
Y
Liu
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China.
Hui-Hui
HH
Qiu
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China.
Nan
N
Yang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China.
Jun-Fei
JF
Gu
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China.
Chun-Fei
CF
Wang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China.
Li
L
Zhang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China.
Jie
J
Song
State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijng 100700, PR China.
Lu-Qi
LQ
Huang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; School of Pharmacy, Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210023, PR China; Third School of Clinical Medical of Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210028, PR China. Electronic address: jxiaobin2005@hotmail.com.
Xiao-Bin
XB
Jia
Department of Pharmacy, Wuxi Xishan People's Hospital, Jiangsu, Wuxi 214011, PR China. Electronic address: jdyx0701.111@163.com.
Ming-Hua
MH
Zhang
Key Laboratory of New Drug Delivery Systems of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, PR China; Third School of Clinical Medical of Nanjing University of Chinese Medicine, Jiangsu, Nanjing 210028, PR China. Electronic address: wenmoxiushi@163.com.
Liang
L
Feng
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D050527:Mesangial Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D029596:Paeonia / Q000737:chemistry; D010766:Phosphorylation; D008517:Phytotherapy; D010946:Plants, Medicinal; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D051437:Renal Insufficiency / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D015398:Signal Transduction / Q000187:drug effects; D013311:Streptozocin; D013729:Terpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D051996:Transcription Factor RelA / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D004365:Drugs, Chinese Herbal; D017127:Glycation End Products, Advanced; D006027:Glycosides; D018836:Inflammation Mediators; D008565:Membrane Proteins; C498145:Rela protein, rat; D013729:Terpenes; D051996:Transcription Factor RelA; C038881:moutan cortex; D013311:Streptozocin; C486557:Ern2 protein, rat; D017346:Protein Serine-Threonine Kinases
4-phenylbutyric acid (PubChem CID: 4775); Anti-inflammation; Benzoylpaeoniflorin (PubChem CID: 102004405); Diabetic nephropathy; Endoplasmic reticulum stress; Moutan Cortex; Oxypaeoniflorin (PubChem CID: 46882883); Paeoniflorin (PubChem CID: 118701402); Streptozotocin (PubChem CID: 45357367); Terpene glycoside component