A fraction from Dojuksan 30% ethanol extract exerts its anti-inflammatory effects through Nrf2-dependent heme oxygenase-1 expression

Dojuksan ameliorates tubulointerstitial fibrosis through irisin-mediated muscle-kidney crosstalk

BACKGROUND

Sarcopenia progresses in chronic kidney disease (CKD) and is positively correlated with mortality in end-stage kidney disease patients. Circulating irisin, an exercise-induced myokine, gradually decreases during CKD stage progression. Irisin inhibits the progression of kidney fibrosis, which is the final common outcome of CKD. Our preliminary study with C2C12 cells showed that Dojuksan, a herbal decoction, increases the expression of PGC1α (a regulator of irisin) and FNDC5 (a precursor of irisin).

HYPOTHESIS

Dojuksan may increase circulating irisin and prevent the progression of kidney fibrosis.

STUDY DESIGN AND METHODS

Unilateral ureteral obstruction (UUO) was performed on seven-week-old male C57BL/6 mice to induce kidney tubulointerstitial fibrosis. Dojuksan (50, 100, or 200 mg/kg/day) or losartan (1.5 mg/kg/day), a standard clinical treatment for CKD, was administered orally one day prior to surgery and continued for seven days thereafter. To determine the role of irisin released from muscles, TGFβ-stimulated murine proximal tubular epithelial cells (mProx24 cells) were treated with conditioned media (CM) from Dojuksan-treated C2C12 muscle cells transfected with FNDC5 siRNA.

RESULTS

UUO mice exhibited muscle wasting along with progressive kidney injury. Similar to losartan, Dojuksan ameliorated kidney inflammation and fibrosis in UUO mice. Dojuksan, but not losartan, increased plasma irisin concentration in UUO mice. Dojuksan significantly increased basal FNDC5 expression and inhibited TNFα-induced and indoxyl sulfate-induced FNDC5 down-regulation in C2C12 cells. The TGFβ-induced collagen I (COL1) up-regulation in mProx24 cells was effectively inhibited by CM from C2C12 cells after Dojuksan treatment. Moreover, irisin inhibited TGFβ-induced COL1 in mProx24 cells, which was not affected by CM from C2C12 cells transfected with FNDC5 siRNA.

CONCLUSION

Dojuksan ameliorates kidney fibrosis through irisin-mediated muscle-kidney crosstalk, suggesting that Dojuksan may be used as an alternative therapeutic agent against CKD.

Screening active components of modified Xiaoyao powder as NRF2 agonists

Nuclear factor (erythroid-derived 2)-like 2 (NRF2) regulates antioxidant enzymes and phase II detoxifying enzymes, such as NAD(P)H: quinone oxidoreductase 1 (NQO1). Modified Xiaoyao powder (MXP) is most frequently used in the prevention and treatment of breast cancer in China. This study aimed to screen active components of MXP for antioxidant stress and chemoprevention, which depend on NRF2-NQO1 signalling pathway. A total of 25 monomeric compounds contained in MXP were screened using an antioxidant response element-luciferase reporter. The most potent antioxidant response element-luciferase inducers were chosen to further examine their effects on NRF2 and NQO1 in MCF-7 cells. These results were then confirmed by determining the oxidative stress levels and chemopreventive effect on inhibiting carcinogenesis transformation in NRF2 knockdown (NRF2^KD ) and NRF2 wild-type MCF-10A cells. We found that quercetin, kaempferol, and atractylenolide II in MXP were potent NRF2 inducers, which could up-regulate the expression of NRF2 and its downstream enzymes NQO1. In addition, these components could decrease reduced oxidative stress and inhibit carcinogenesis transformation, which depended on NRF2-NQO1 pathway. In conclusion, NRF2-NQO1 pathway plays an essential role in mediating the activity of MXP and its active components, at least in part; some beneficial effects of MXP may be applicable to breast cancer chemoprevention. Our study firstly found MXP active components including quercetin, kaempferol, and atractylenolide II. Our results firstly demonstrate that NRF2-NQO1 pathway plays an essential role in mediating the activity of MXP and its active components in breast cancer chemoprevention. Our study firstly found that atractylenolide II is a novel NRF2 inducer.