Differential toxicities of triptolide to immortalized podocytes and the podocytes in vivo

Triptolide inhibits oxidative stress and inflammation via the microRNA-155-5p/brain-derived neurotrophic factor to reduce podocyte injury in mice with diabetic nephropathy

Diabetic nephropathy (DN) is a complication of diabetes. This study sought to explore the mechanism of triptolide (TP) in podocyte injury in DN. DN mice were induced by high-fat diet&streptozocin and treated with TP. Fasting blood glucose, 24 h urine microalbumin (UMA), the pathological changes of renal tissues, and ultrastructure of renal podocytes were observed. Podocytes (MPC5) were induced by high-glucose (HG) in vitro and treated with TP or microRNA (miR)-155-5p mimics, with Irbesartan as positive control. Reactive oxygen species (ROS) and levels of oxidative stress (OS) and inflammatory factors in MPC5 were detected. The levels of miR-155-5p, podocyte marker protein Nephrin, and inflammatory factors in mice and MPC5 were detected. The targeting relationship between miR-155-5p and brain-derived neurotrophic factor (BDNF) was verified. The expression levels of BDNF were detected. miR-155-5p mimics and overexpressed (oe)-BDNF plasmids were co-transfected into mouse podocytes treated with HG and TP. TP reduced fasting glucose and 24 h UMA of DN mice, alleviated the pathological damage and podocyte injury, up-regulated Nephrin level, and down-regulated miR-155-5p. TP down-regulated the high expression of miR-155-5p in HG-induced MPC5 cells and inhibited HG-induced OS and inflammatory injury, and the improvement effect of TP was better than Irbesartan. Overexpression of miR-155-5p reversed the protective effect of TP on injured mouse podocytes. miR-155-5p targeted BDNF. oe-BDNF reversed the inhibitory effect of oe-miR-155-5p on TP protection on podocyte injury in mice. Overall, TP up-regulated BDNF by inhibiting miR-155-5p, thus inhibiting OS and inflammatory damage and alleviating podocyte injury in DN mice.

Effectiveness and safety of KunXian capsule for the treatment of IgA nephropathy

BACKGROUND

Tripterygium Wilfordii Hook F (TwHF) preparation has been widely used in the treatments of IgA nephropathy (IgAN) in China. However, the effectiveness and safety of the new generation of TwHF preparation, KuxXian capsule, on the treatment of IgAN remains unknown.

METHODS

Here, we retrospectively describe our experience treating 55 consecutive IgAN patients with KunXian. We defined complete remission as proteinuria < 0.5 g/24 h and partial remission as proteinuria < 1 g/24 h, each also having > 50% reduction in proteinuria from baseline.

RESULTS

At first follow-up after KunXian treatment (5.7 weeks, IQR 4.7-7.9), all but two patients (96%) showed a reduction in proteinuria. The overall median proteinuria decreased from 2.23 g/day at baseline to 0.94 g/day (P < 0.001) at the first follow-up. During a median follow-up of 28 weeks after KunXian administration, 25(45.5%) patients achieved complete remission, 34 (61.8%) patients achieved complete/partial remission. Of the 12 patients discontinued KunXian treatment during the follow-up, the median proteinuria was increased from 0.97 g/24 h to 2.74 g/24 h after a median of 10.9 weeks (P = 0.004). Multivariable Cox models showed that female, treatment switching from previous generation of TwHF preparation, lower initial KunXian dosage, and higher proteinuria at baseline were independently associated proteinuria remission. Of the 20 pre-menopausal females, 12 of them developed oligomenorrhea or menstrual irregularity and ten of them developed amenorrhea.

CONCLUSION

KunXian is effectiveness and safety for the treatment of IgA nephropathy. Woman of childbearing age to be informed of the risk of ovarian failure after being treated with TwHF preparations.

Microcystin-LR induces ovarian injury and apoptosis in mice via activating apoptosis signal-regulating kinase 1-mediated P38/JNK pathway

As an emerging pollutant in the aquatic environment, microcystin-LR (MC-LR) can enter the body through multiple pathways, and then induce apoptosis and gonadal damage, affecting reproductive function. Previous studies focused on male reproductive toxicity induced by MC-LR neglecting its effects on females. The apoptotic signal-regulated kinase 1 (ASK1) is an upstream protein of P38/JNK pathway, closely associated with apoptosis and organ damage. However, the role of ASK1 in MC-LR-induced reproductive toxicity is unclear. Therefore, this study investigated the role of ASK1 in mouse ovarian injury and apoptosis induced by MC-LR. After MC-LR exposure, ASK1 expression in mouse ovarian granulosa cells was increased at the protein and mRNA levels, and decreased following pretreatment by antioxidant N-acetylcysteine, suggesting that MC-LR-induced oxidative stress has a regulatory role in ASK1 expression. Inhibition of ASK1 expression with siASK1 and NQDI-1 could effectively alleviate MC-LR-induced mitochondrial membrane potential damage and apoptosis in ovarian granulosa cells, as well as pathological damage, apoptosis and the decreased gonadal index in ovaries of C57BL/6 mice. Moreover, the P38/JNK pathway and downstream apoptosis-related proteins (P-P38, P-JNK, P-P53, Fas) and genes (MKK4, MKK3, Ddit3, Mef2c) were activated in vivo and vitro, but their activation was restrained after ASK1 inhibition. Data presented herein suggest that the ASK1-mediated P38/JNK pathway is involved in ovarian injury and apoptosis induced by MC-LR in mice. It is confirmed that ASK1 has an important role in MC-LR-induced ovarian injury, which provides new insights for preventing MCs-induced reproductive toxicity in females.

Triptolide inhibits tonsillar IgA production by upregulating FDC-SP in IgA nephropathy

IgA nephropathy (IgAN) is primarily resulted of qualitative abnormality of IgA. The occurrence of IgAN is associated with affected tonsils which enhances the IgA production via IgA class switching and immuno-activation. Follicular dendritic cell-secreted protein (FDC-SP) was found to be a negative effect for IgA production in tonsil. The previous studies suggested that Triptolide might reduce IgA production by its immunosuppression role. Given this background, this study investigated the mechanisms underlying the role of Triptolide and FDC-SP in the generation of IgA and IgA class switching in tonsil of IgAN patients. Immunohistochemistry and reverse transcription-polymerase chain reaction revealed that the expression of FDC-SP was increased in the tonsils of IgAN patients with Triptolide treatment compared with those without treatment. Meanwhile, the expression of FDC-SP was negatively correlated with IgA inducing cytokines in the tonsils of IgAN patients treated with Triptolide, due to the significant decreased IgA-bearing cells. The expression of FDC-SP in tonsillar tissue was confirmed by double immunofluorescence. Importantly, Triptolide promoted FDC-SP secretion, and correlated negatively with decreased IgA production in isolated FDC-associated clusters, which had been isolated from patients without TW treatment previously. Our study demonstrated that Triptolide might have an impact on FDC-SP production and downregulation of IgA synthesis in the tonsils of IgAN patients, which could be a promising strategy for therapeutic intervention in IgAN patients.

A review of the total syntheses of triptolide

Triptolide is a complex triepoxide diterpene natural product that has attracted considerable interest in the organic chemistry and medicinal chemistry societies due to its intriguing structural features and multiple promising biological activities. In this review, progress in the total syntheses of triptolide are systematically summarized. We hope to gain a better understanding of the field and provide constructive suggestions for future studies of triptolide.