[Effect and mechanism of Jiedu Huoxue Decoction in regulating YAP/ACSL4 pathway to inhibit ferroptosis in treatment of acute kidney injury].

Jiedu Huoxue Decoction(JDHX), first recorded in the Correction on Errors in Medical Works by WANG Qing-ren, is an effective formula screened out from ancient formulas by the traditional Chinese medicine(TCM) master ZHANG Qi to treat acute kidney injury(AKI) caused by heat, toxicity, stasis, and stagnation. This paper elucidated the therapeutic effect of JDHX on AKI and probed into the potential mechanism from ferroptosis. Thirty-two male C57BL/6 mice were randomized into four groups(n=8): normal, model, and low-and high-dose JDHX. Since the clinical treatment of AKI depends on supportive or alternative therapies and there is no specific drug, this study did not include a positive drug group. The low dose of JDHX corresponded to half of clinically equivalent dose, while the high dose corresponded to the clinically equivalent dose. Mice were administrated with JDHX by gavage daily for 7 consecutive days, while those in the normal group and the model group were administered with the corresponding volume of distilled water. On day 5 of drug administration, mice in other groups except the normal group were injected intraperitoneally with cisplatin solution at a dose of 20 mg·kg~(-1) to induce AKI, and the normal group was injected with saline. All of the mice were sacrificed 72 h after modeling, blood and kidney samples were collected for subsequent analysis. The levels of serum creatine(Scr) and blood urea nitrogen(BUN) were measured by the commercial kits. The expression level of kidney injury molecule 1(KIM-1) in the serum was measured by enzyme-linked immunosorbent assay. Hematoxylin-eosin(HE) staining, periodic acid-Schiff(PAS) staining, and Prussian blue staining were employed to observe the pathological changes, glycogen deposition, and iron deposition, respectively, in the renal tissue. In addition, the levels of glutathione(GSH), superoxide dismutase(SOD), and catalase(CAT) in the renal tissue were examined by biochemical colorimetry. Western blot was performed to determine the protein levels of acyl-CoA synthetase long chain family member 4(ACSL4), lysophosphatidylcholine acyltransferase 3(LPCAT3), and Yes-associated protein(YAP, a key molecule in the Hippo pathway) in the renal tissue. Immunohistochemistry was then employed to detect the location and expression of YAP in the renal tissue. Real-time fluorescence quantitative polymerase chain reaction(qRT-PCR) was performed to measure the mRNA levels of ACSL4 and glutathione peroxidase 4(GPX4). Compared with the normal group, the model group showed elevated serum levels of Scr, BUN, and KIM-1. In the AKI model group, the tubular epithelial cells underwent atrophy and necrotic detachment, disappearance of brush border, and some tubules became protein tubules or experienced vacuole-like degeneration. In addition, this group presented widening of the interstitium or even edema, increased renal tubule injury score, and obvious glycogen and iron deposition in parts of the renal tissue. Moreover, the model group had lower GSH, SOD, and CAT levels, higher ASCL4 and LPCAT3 levels, and lower GPX4 expression and higher YAP expression than the normal group. Compared with the model group, high dose of JDHX effectively protected renal function, lowered the levels of Scr, BUN and KIM-1, alleviated renal pathological injury, reduced glycogen and iron deposition, and elevated the GSH, SOD, and CAT levels in the renal tissue. Furthermore, JDHX down-regulated the protein levels of ACSL4, LPCAT3, and YAP and up-regulated the level of GPX4, compared with the model group. In conclusion, JDHX can protect mice from cisplatin-induced AKI by inhibiting ferroptosis via regulating the YAP/ACSL4 signaling pathway.

[Leonurine inhibits ferroptosis in renal tubular epithelial cells by activating p62/Nrf2/HO-1 signaling pathway].

To investigate the protective effect and the potential mechanism of leonurine(Leo) against erastin-induced ferroptosis in human renal tubular epithelial cells(HK-2 cells), an in vitro erastin-induced ferroptosis model was constructed to detect the cell viability as well as the expressions of ferroptosis-related indexes and signaling pathway-related proteins. HK-2 cells were cultured in vitro, and the effects of Leo on the viability of HK-2 cells at 10, 20, 40, 60, 80 and 100 µmol·L~(-1) were examined by CCK-8 assay to determine the safe dose range of Leo administration. A ferroptosis cell model was induced by erastin, a common ferroptosis inducer, and the appropriate concentrations were screened. CCK-8 assay was used to detect the effects of Leo(20, 40, 80 µmol·L~(-1)) and positive drug ferrostatin-1(Fer-1, 1, 2 µmol·L~(-1)) on the viability of ferroptosis model cells, and the changes of cell morphology were observed by phase contrast microscopy. Then, the optimal concentration of Leo was obtained by Western blot for nuclear factor erythroid 2-related factor 2(Nrf2) activation, and transmission electron microscope was further used to detect the characteristic microscopic morphological changes during ferroptosis. Flow cytometry was performed to detect reactive oxygen species(ROS), and the level of glutathione(GSH) was measured using a GSH assay kit. The expressions of glutathione peroxidase 4(GPX4), p62, and heme oxygenase 1(HO-1) in each group were quantified by Western blot. RESULTS:: showed that Leo had no side effects on the viability of normal HK-2 cells in the concentration range of 10-100 µmol·L~(-1). The viability of HK-2 cells decreased as the concentration of erastin increased, and 5 µmol·L~(-1) erastin significantly induced ferroptosis in the cells. Compared with the model group, Leo dose-dependently increased cell via-bility and improved cell morphology, and 80 µmol·L~(-1) Leo promoted the translocation of Nrf2 from the cytoplasm to the nucleus. Further studies revealed that Leo remarkably alleviated the characteristic microstructural damage of ferroptosis cells caused by erastin, inhibited the release of intracellular ROS, elevated GSH and GPX4, promoted the nuclear translocation of Nrf2, and significantly upregulated the expression of p62 and HO-1 proteins. In conclusion, Leo exerted a protective effect on erastin-induced ferroptosis in HK-2 cells, which might be associated with its anti-oxidative stress by activating p62/Nrf2/HO-1 signaling pathway.

Tripterygium glycoside fraction n2 ameliorates adriamycin-induced nephrotic syndrome in rats by suppressing apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Tripterygium wilfordii Hook F. (TwHF), a traditional Chinese herb medicine, has been widely used for clinical treatment of various rheumatic immune diseases. Tripterygium glycosides (TG) extracted from TwHF has been verified to process multiple bioactivities, including immunosuppressive, anti-inflammatory and anti-cancer effects. However, the clinical application of TG is limited due to its severe toxicity and narrow therapeutic window. For the clinical safety of TG usage, attenuation of toxicity is the key issue to be solved. PURPOSE: Tripterygium glycoside fraction n2 (TG-n2) is a detoxified mixture obtained from TG using a new preparation method. In our previous study, we have demonstrated that TG-n2 has a lower toxicity than TG. The aim of the present study was to screen the renal protective effect of TG-n2 in nephrotic syndrome (NS) induced by adriamycin (ADR) in rats and its effect on apoptosis, as well as the effective difference between TG-n2 and TG. MATERIALS AND METHODS: The ADR-induced NS rat model was established. Rats were intravenously injected with ADR (6 mg/kg), then treated with either TG-n2 (10 mg/kg/day) or TG (10 mg/kg/day) by oral gavage for 4 weeks. Clinical indexes in each group were determined. HE staining and electron microscopic analysis were used to evaluate renal histopathological damage. Caspase-3 activity reagent and TUNEL staining were used to estimate renal apoptosis. Protein levels of caspase-3, caspase-9, caspase-8, caspase-12, Bax, Bcl-2, p53, TNF-R1, FLIP and podocin were measured by Western Blot. RESULTS: TG-n2 and TG intervention ameliorated renal function as assessed by the levels of 24-h proteinuria, Cr, BUN, TC, TG, ALB and LDL-c. TG-n2 and TG alleviated the decrease of podocin protein expression and morphological injury of podocyte as screened by Western Blot and electron microscopic analysis. Besides, renal tubular injury was reduced as inspected by light microscopic analysis. TG-n2 and TG could significantly inhibit the apoptosis and activity of caspase-3 in kidney tissues as examined by fluorescence microscopic analysis and reagent. After intervention of TG-n2 and TG, protein levels of cleaved caspase-3, cleaved caspase-8, cleaved caspase-9, Bax, p53 and TNF-R1 in renal issues were significantly decreased compared with ADR group. In contrast, protein level of Bcl-2 was elevated remarkedly. CONCLUSIONS: Our data suggested that attenuated TG-n2 may have a similar protective effect with TG in ADR-induced NS in rats by inhibiting activation of apoptosis.

Triptriolide antagonizes triptolide-induced nephrocyte apoptosis via inhibiting oxidative stress in vitro and in vivo.

Triptolide(T9) is a predominant bioactive component extracted from Chinese herb Tripterygium wilfordii Hook F. (TwHF), and has multiple pharmacological activities, such as immunosuppressive and anti-inflammatory activities, et al. However, severe adverse effects and toxicity, particularly nephrotoxicity, limit its clinical application. It has been demonstrated that the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway could alleviate T9-induced nephrocyte damage. The aim of this study was to investigate the potential protective role of triptriolide (T11) against T9-induced nephrocyte apoptosis in vitro and in vivo. Renal injury models were established in human kidney 2 (HK2) cells and BALB/c mice using T9, and the protective effects of T11 were probed in vitro and in vivo, respectively. T9 induced nephrocyte damage in HK2 cells and BALB/c mice by induction of reactive oxygen species (ROS), lactate dehydrogenase (LDH), malondialdehyde (MDA) and glutathione (GSH) and reduction of superoxide dismutase (SOD), which resulted in the apoptosis of nephrocyte and injury of renal function. While, pretreatment of T11 effectively reversed these changes, resulting in the obvious decrease of oxidative stress and renal function parameters, ameliorated nephrocyte apoptosis, improved cell morphology, and higher increase of Nrf2, NAD(P)H: quinine oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1) protein levels in vitro and in vivo. Altogether, T11 protected against T9-induced nephrocyte apoptosis possibly via suppressing oxidative stress.

Dual-function of triptriolide in podocytes injury: inhibiting of apoptosis and restoring of survival.

Triptriolide (T11) is a natural diterpene diepoxide that derived from Chinese traditional herb medicine (TCHM) Tripterygium wilfordii Hook.F (TWHF). From a structural point of view, T11 is very similar to triptolide (T9), one of the most effectively compounds in TWHF that have already been systematically investigated in the past decades. However, the basic functions and medicinal properties of T11 have not yet been well investigated mainly due to its low abundance in its plant organ. The present study aimed to investigate the protective effects of T11 on puromycin aminonucleoside (PAN) induced apoptotic mouse podocytes and the underlying mechanism. The results showed that T11 had no significant toxicity in podocytes in high dosage, and showed prominent protective effects on PAN induced podocytes injury. Further studies indicated that T11 might exert its protective effects by inhibiting of apoptosis and restoring of survival in PAN induced podocytes.

Triptriolide Alleviates Lipopolysaccharide-Induced Liver Injury by Nrf2 and NF-κB Signaling Pathways.

Nrf2 (Nuclear Factor Erythroid 2 Related Factor 2) transcription factor not only regulates oxidative stress response, but also represses inflammation by regulating cytokines production and cross-talking with NF-κB signaling pathways. Nrf2 plays an essential role in liver injury induced by oxidative stress and inflammation. Triptriolide (T11) is a minor component of Tripterygium wilfordii Hook F. (TwHF), which can be obtained by hydrolysis reaction of triptolide (T9). The major purpose of this study is to clarify the regulating effects of T11 on oxidative stress and inflammation in vivo and in vitro. LPS-stimulated RAW 264.7 cells were used to verify the regulating effects of T11 on oxidative stress (ROS and Nrf2 signaling pathway) and inflammatory cytokines production (TNF-α, IL-6 and IL-1ß). The antioxidant responsive element (ARE) luciferase assay was employed to evaluate Nrf2 activation effect of T11 in HEK-293T cells. Lipopolysaccharides (LPS) induced acute liver injury (ALI) in BALB/c mice were used to study the protective effects (ALT, AST, MDA, SOD, histopathology and neutrophils/macrophages filtration) and the underlying protection mechanisms of ALI amelioration (Nrf2 and NF-κB signaling pathway) of T11. Firstly, the results showed that T11 can not only effectively decrease the productions of inflammatory cytokines (TNF-α, IL-6 and IL-1ß), ROS and NO in LPS-stimulated RAW 264.7 cells, but also further significantly increase the activity of Nrf2 in HEK-293T cells. Secondly, the results suggested that T11 could dramatically decrease the oxidative stress responses (SOD and MDA) and inflammation (histopathology, neutrophils/macrophages filtration, TNF-α, IL-6 and IL-1ß production) in LPS-induced ALI in BALB/c mice. Finally, the results implied that T11 could dramatically increase Nrf2 protein expression and decrease p-TAK1, p-IκBα and NF-κB protein expression both in vivo and in vitro. In conclusion, our findings indicated that T11 could alleviate LPS induced oxidative stress and inflammation by regulating Nrf2 and NF-κB signaling pathways in vitro and in vivo, which offers a novel insights for the application of TwHF in clinical.