The renoprotective effect of diosgenin on aristolochic acid I-induced renal injury in rats: impact on apoptosis, mitochondrial dynamics and autophagy

In vivo targeted-imaging of mitochondrial acidification in an aristolochic acid I-induced nephrotoxicity mouse model by a fluorescent/photoacoustic bimodal probe

Aristolochic acid I (AAI), a natural compound in aristolochia type Chinese medicinal herb, is generally acknowledged to have nephrotoxicity, which may be associated with mitophagy. Mitophagy is a cellular process with important functions that drive AAI-induced renal injury. Mitochondrial pH is currently measured by fluorescent probes in cell culture, but existing probes do not allow for in situ imaging of AAI-induced mitophagy in vivo. We developed a ratiometric fluorescent/PA dual-modal probe with a silicon rhodamine fluorophore and a pH-sensitive hemicyanine dye covalently linked via a short chain to obtain a FRET type probe. The probe was used to measure AAI-mediated mitochondrial acidification in live cells and in vivo. The Förster resonance energy transfer (FRET)-mediated ratiometric and bimodal method can efficiently eliminate signal variability associated with the commonly used one-emission and single detection mode by ratiometric two channels of the donor and acceptor. The probe has good water-solubility and low molecular weight with two positively charged, facilitating its precise targeting into renal mitochondria, where the fluorescent/PA changes in response to mitochondrial acidification, enabling dynamic and semi-quantitative mapping of subtle changes in mitochondrial pH in AAI-induced nephrotoxicity mouse model for the first time. Also, the joint use of L-carnitine could mitigate the mitophagy in AAI-induced nephrotoxicity.

Activation of LONP1 by 84-B10 alleviates aristolochic acid nephropathy via re-establishing mitochondrial and peroxisomal homeostasis

Pharmaceutical formulations derived from Aristolochiaceae herbs, which contain aristolochic acids (AAs), are widely used for medicinal purposes. However, exposure to these plants and isolated AAs is linked to renal toxicity, known as AA nephropathy (AAN). Currently, the mechanisms underlying AAN are not fully understood, leading to unsatisfactory treatment strategies. In this study, we explored the protective role of 84-B10 (5-[[2-(4-methoxyphenoxy)-5-(trifluoromethyl) phenyl] amino]-5-oxo-3-phenylpentanoic acid) against AAN. RNA-seq analysis revealed that the mitochondrion and peroxisome were the most affected cellular components following 84-B10 treatment in AAN mice. Consistently, 84-B10 treatment preserved mitochondrial ultrastructure, restored mitochondrial respiration, enhanced the expression of key transporters (carnitine palmitoyltransferase 2) and enzymes (acyl-Coenzyme A dehydrogenase, medium chain) involved in mitochondrial fatty acid β-oxidation, and reduced mitochondrial ROS generation in both aristolochic acid I (AAI)-challenged mice kidneys and cultured proximal tubular epithelial cells. Additionally, 84-B10 treatment increased the expression of key transporters (ATP binding cassette subfamily D) and rate-limiting enzymes (acyl-CoA oxidase 1) involved in peroxisomal fatty acid β-oxidation and restored peroxisomal redox balance. Knocking down LONP1 expression diminished the protective effects of 84-B10 against AAN, suggesting LONP1-dependent protection. In conclusion, our study provides evidence that AAN is associated with significant disturbances in both mitochondrial and peroxisomal functions. The LONP1 activator 84-B10 demonstrates therapeutic potential against AAN, likely by maintaining homeostasis in both mitochondria and peroxisomes.

Diosgenin Reduces Acute Kidney Injury and Ameliorates the Progression to Chronic Kidney Disease by Modifying the NOX4/p65 Signaling Pathways

Acute kidney injury (AKI), if not well controlled, may progress to chronic kidney disease (CKD). Diosgenin is a natural phytosteroid sapogenin from plants. This study aimed to investigate the mechanistic effects of diosgenin on AKI and AKI related development of CKD. The mouse model of ischemia/reperfusion (I/R)-induced AKI was used, and its progressive changes were followed. Human renal proximal tubular epithelial cells were used, and hypoxia stimulation was applied to mimic the in vivo I/R. Diosgenin, given after renal injury, preserved kidney function, as evidenced by a reduction in serum levels of BUN, creatinine, and UACR in both acute and chronic phases of AKI. Diosgenin alleviated I/R-induced tubular injury and prevented macrophage infiltration and renal fibrosis in AKI mice. Furthermore, diosgenin also mitigated the development of CKD from AKI with reduced renal expression of inflammatory, fibrotic, and epithelial-mesenchymal transition markers. In human renal tubular epithelial cells, diosgenin downregulated the hypoxia-induced oxidative stress and cellular damages that were dependent on the NOX4/p65 signaling pathways. Taken together, diosgenin treatment reduced I/R-induced AKI and ameliorated the progression to CKD from AKI probably by modifying the NOX4/p65 signaling pathways.

Catalpol from Rehmannia glutinosa Targets Nrf2/NF-κB Signaling Pathway to Improve Renal Anemia and Fibrosis

Rehmannia glutinosa is widely recognized as a prominent medicinal herb employed by practitioners across various generations for the purpose of fortifying kidney yin. Within Rehmannia glutinosa, the compound known as catalpol (CAT) holds significant importance as a bioactive constituent. However, the protective effects of CAT on kidneys, including ameliorative effects on chronic kidney disease - most prominently renal anemia and renal fibrosis - have not been clearly defined. In this study, the kidney injury model of NRK-52E cells and C57BL/6N male mice was prepared by exposure to aristolochic acid I (AA-I), and it was discovered that CAT could ameliorate oxidative stress injury, inflammatory injury, apoptosis, renal anemia, renal fibrosis, and other renal injuries both in vivo and in vitro. Further treatment of NRK-52E cells with Nrf2 inhibitors (ML385) and activators (ML334), as well as NF-κB inhibitors (PDTC), validated CAT's ability to target Nrf2 activation. Furthermore, the expression of phosphorylated NF-κB p65, IL-6, and Cleaved-Caspase3 protein was inhibited. CAT also inhibited NF-κB, and then inhibited the expression of IL-6, p-STAS3, TGF-β1 protein. Therefore, CAT can regulate Nrf2/NF-κB signaling pathway, significantly correct renal anemia and renal fibrosis, and is conducive to the preservation of renal structure and function, thus achieving a protective effect on the kidneys.

The multifaceted potential of fenugreek seeds: From health benefits to food and nanotechnology applications

The present lifestyle, dietary patterns, psychological pressure, environmental factors, and the widespread exploitation of processed substances in food production and farming have collectively contributed to a substantial expediting in the development of various health problems. Globally, researchers have been seeking natural pharmaceutical substances with the potential to be employed in treating lifestyle-related diseases or delaying their onset. Fenugreek seeds have gained significant attention in various fields, including health, nutrition, and cutting-edge nanotechnology applications, due to their versatile qualities. The current investigation offers a comprehensive discussion of the nutritional composition and therapeutic potential of fenugreek seeds, with an emphasis on their plentiful reservoir of bioactive compounds. This seed demonstrates promising medicinal potential in addressing a wide range of health issues. Significantly, these findings indicate noteworthy properties, such as antidiabetic, antioxidant, anti-obesity, hypocholesterolemic, anticancer, and cardioprotective effects. Moreover, the components of fenugreek seeds are important in the development of a multitude of foods, which is the reason why they are used extensively in the area of food research. In addition to their nutritional value, their exploration of nanotechnology reveals a promising domain, utilizing the distinctive characteristics of seeds for many purposes, such as nanoparticle synthesis and oil for edible films and nanoemulsions. This review article focuses on a comprehensive analysis of fenugreek seeds, examining their wide-ranging applications in the fields of health, nutrition, food, and nanotechnology.

The multifaceted potential of fenugreek seeds: From health benefits to food and nanotechnology applications

The present lifestyle, dietary patterns, psychological pressure, environmental factors, and the widespread exploitation of processed substances in food production and farming have collectively contributed to a substantial expediting in the development of various health problems. Globally, researchers have been seeking natural pharmaceutical substances with the potential to be employed in treating lifestyle‐related diseases or delaying their onset. Fenugreek seeds have gained significant attention in various fields, including health, nutrition, and cutting‐edge nanotechnology applications, due to their versatile qualities. The current investigation offers a comprehensive discussion of the nutritional composition and therapeutic potential of fenugreek seeds, with an emphasis on their plentiful reservoir of bioactive compounds. This seed demonstrates promising medicinal potential in addressing a wide range of health issues. Significantly, these findings indicate noteworthy properties, such as antidiabetic, antioxidant, anti‐obesity, hypocholesterolemic, anticancer, and cardioprotective effects. Moreover, the components of fenugreek seeds are important in the development of a multitude of foods, which is the reason why they are used extensively in the area of food research. In addition to their nutritional value, their exploration of nanotechnology reveals a promising domain, utilizing the distinctive characteristics of seeds for many purposes, such as nanoparticle synthesis and oil for edible films and nanoemulsions. This review article focuses on a comprehensive analysis of fenugreek seeds, examining their wide‐ranging applications in the fields of health, nutrition, food, and nanotechnology.

PSTPIP2 ameliorates aristolochic acid nephropathy by suppressing interleukin-19-mediated neutrophil extracellular trap formation

Aristolochic acid nephropathy (AAN) is a progressive kidney disease caused by herbal medicines. Proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2) and neutrophil extracellular traps (NETs) play important roles in kidney injury and immune defense, respectively, but the mechanism underlying AAN regulation by PSTPIP2 and NETs remains unclear. We found that renal tubular epithelial cell (RTEC) apoptosis, neutrophil infiltration, inflammatory factor, and NET production were increased in a mouse model of AAN, while PSTPIP2 expression was low. Conditional knock-in of Pstpip2 in mouse kidneys inhibited cell apoptosis, reduced neutrophil infiltration, suppressed the production of inflammatory factors and NETs, and ameliorated renal dysfunction. Conversely, downregulation of Pstpip2 expression promoted kidney injury. In vivo, the use of Ly6G-neutralizing antibody to remove neutrophils and peptidyl arginine deiminase 4 (PAD4) inhibitors to prevent NET formation reduced apoptosis, alleviating kidney injury. In vitro, damaged RTECs released interleukin-19 (IL-19) via the PSTPIP2/nuclear factor (NF)-κB pathway and induced NET formation via the IL-20Rβ receptor. Concurrently, NETs promoted apoptosis of damaged RTECs. PSTPIP2 affected NET formation by regulating IL-19 expression via inhibition of NF-κB pathway activation in RTECs, inhibiting RTEC apoptosis, and reducing kidney damage. Our findings indicated that neutrophils and NETs play a key role in AAN and therapeutic targeting of PSTPIP2/NF-κB/IL-19/IL-20Rβ might extend novel strategies to minimize Aristolochic acid I-mediated acute kidney injury and apoptosis.

Acer truncatum Bunge seed oil ameliorated oxaliplatin-induced demyelination by improving mitochondrial dysfunction via the Pink1/Parkin mitophagy pathway

Dietary nutritional support for special populations is an effective and feasible method to improve the quality of life of patients and reduce medical pressure. Acer truncatum Bunge seed oil (ATSO) is widely recognized for its ability to promote nerve myelin regeneration. To evaluate the ameliorative effects of ATSO on chemotherapy-induced demyelination, a zebrafish model of chemotherapy-induced demyelination was established. The results showed that 100 μg mL-1 of ATSO reversed tail morphology damage, axon degeneration, touch response delay, ROS level upregulation and the expression of myelin basic protein decrease in chemotherapy-induced zebrafish. In addition, the expression of myelin markers (including sox10, krox20, and pmp22) in oxaliplatin-induced cells was markedly reversed by ATSO and its active components (gondoic acid, erucic acid, and nervonic acid). ATSO and its active components could reverse demyelination by ameliorating mitochondrial dysfunction. Conversely, linoleic acid and linolenic acid promoted demyelination by exacerbating mitochondrial dysfunction. Moreover, the Pink1/Parkin pathway was recognized as the main reason for ATSO and its active components improving mitochondrial function by activating mitophagy and restoring autophagic flow. Taken together, this study demonstrated that ATSO and its active components could be further developed as novel functional food ingredients to antagonize demyelination.

Safety of Innovative Nanotechnology Oral Formulations Loaded with Bioactive Menopause Molecules: Influence of Genotoxicity and Biochemical Parameters on a Menopausal Rat Model

In recent years, nanoparticles have gained significant importance due to their unique properties, such as pharmacological, electrical, optical, and magnetic abilities, contributing to the growth of the science and technology sector. Particular naturally derived biomolecules with beneficial effects on menopause disorder have been the subject of studies of pharmaceutical formulation to obtain alternative pharmaceutical forms with increased bioavailability and without side effects, as in nanostructured lipid carriers (NLCs) loaded with such active ingredients. In the present study, one stage of a broader project, we have performed pharmacotoxicology studies for six combinatory innovative nanocapsule pharmaceutical forms containing active natural biomolecules before considering them as oral formulas for (1) in vitro toxicity studies on culture cells and (2) in vivo preclinical studies on a surgically induced menopause model of Wistar female rats, and the influence of the NLCs on key biochemical parameters: lipid profile (TG, Chol, HDL), glycemic markers (Gli), bone markers (Pac, Palc, Ca, phosphorus), renal markers (Crea, urea, URAC), inflammation (TNF), oxidative stress (GSH, MDA), and estrogen-progesterone hormonal profile. The micronucleus test did not reveal the genotoxicity of the tested compounds; the menopause model showed no significant safety concerns for the six tested formulas evaluated using the blood biochemical parameters; and the results showed the potential hypoglycemic, hypolipidemic, hypouricemic, and antioxidant potential of one of the tested formulas containing nano diosgenin and glycyrrhizic acid.

Targeting Mitochondrial Dysfunction in Neurodegenerative Diseases: Expanding the Therapeutic Approaches by Plant-Derived Natural Products

Mitochondria are the primary source of energy production in neurons, supporting the high energy consumption of the nervous system. Inefficient and dysfunctional mitochondria in the central nervous system have been implicated in neurodegenerative diseases. Therefore, targeting mitochondria offers a new therapeutic opportunity for neurodegenerative diseases. Many recent studies have proposed that plant-derived natural products, as pleiotropic, safe, and readily obtainable sources of new drugs, potentially treat neurodegenerative diseases by targeting mitochondria. In this review, we summarize recent advances in targeting mitochondria in neurotherapeutics by employing plant-derived natural products. We discuss the mechanism of plant-derived natural products according to their mechanism of action on mitochondria in terms of regulating biogenesis, fusion, fission, bioenergetics, oxidative stress, calcium homeostasis, membrane potential, and mitochondrial DNA stability, as well as repairing damaged mitochondria. In addition, we discuss the potential perspectives and challenges in developing plant-derived natural products to target mitochondria, highlighting the clinical value of phytochemicals as feasible candidates for future neurotherapeutics.

Lycopene attenuates the inflammation and apoptosis in aristolochic acid nephropathy by targeting the Nrf2 antioxidant system

Lycopene (LYC) is a carotenoid, has antioxidant properties. This study investigated whether lycopene attenuates aristolochic acids (AAs) -induced chronic kidney disease. In this experiment, lycopene was used to intervene C57BL/6 mice with renal injury induced by aristolochic acid exposure. The histomorphological changes and serological parameters of the kidney were measured in order to assess the alleviating effect of lycopene on renal injury in aristolochic acid nephropathy. In vitro and in vivo experiments were carried out to verify the main mechanism of action and drug targets of lycopene in improving aristolochic acid nephropathy (AAN) and by various experimental methods such as ELISA, immunohistochemistry, immunofluorescence, Western-blot and qRT-PCR. The results showed that oxidative stress injury was induced in the kidney of mice after AAI exposure, resulting in inflammatory response and tubular epithelial cell apoptosis. The results showed that the Nrf2/HO-1 antioxidant signaling pathway was inhibited after AAI exposure. AAI induces oxidative stress injury in the kidney, which ultimately leads to inflammation and tubular epithelial cell apoptosis. After LYC intervened in the body, it activated Nrf2 nuclear translocation and its downstream HO-1 and NQO1 antioxidant signaling pathways. LYC inhibited ROS production by renal tubular epithelial cells, and alleviated mitochondrial damage. LYC further modulated the TNF-α/NF-κB signaling cascade, thereby reduced the accumulation of inflammatory factors in the renal interstitium. Moreover, LYC was able to up-regulate the expression of Bcl-2, down-regulate Bax expression and inhibit the activation of cleaved forms of Caspase-9 and Caspase-3, which finally attenuated the apoptosis of the mitochondrial pathway induced by AAI exposure. It was concluded that lycopene was able to activate the Nrf2 antioxidant signaling pathway to maintain the homeostasis of renal oxidative stress and ultimately attenuated renal inflammatory response and apoptosis. These results suggested that lycopene can be used as a drug to relieve AAN.

Curcumin alleviates aristolochic acid nephropathy based on SIRT1/Nrf2/HO-1 signaling pathway

Aristolochic acid I (AA-I), presenting in a variety of natural medicinal plants, which could cause tubular epithelial cell injury. Curcumin (CUR), a polyphenolic substance isolated from turmeric, is a natural antioxidant. The aim of this experiment was to investigate whether CUR attenuated AA-I-induced renal injury in rats through the SIRT1/Nrf2/HO-1 signaling pathway. SD rats were treated with AA-I (10 mg/kg) or/and CUR (200 mg/kg) for 28 days to assess the protective effect of CUR on AA-I-induced renal injury in vivo. NRK-52E cells were treated with AA-I (40 μ M) or/and CUR (20 μ M) for 24 h in vitro. The intervention pathway of CUR against oxidative stress injury induced by AA-I was assessed by observing pathological changes, oxidative stress status, apoptosis and the expression of SIRT1/Nrf2/HO-1 signaling pathway-related factors. The results showed that AA-I exposure increased the contents of BUN, Cr, KIM-1, NGAL, ALT and AST in serum. It increased the content of MDA, decreased the activities of SOD, GST, GSH and the content of ATP in renal tissue. Pathological changes such as inflammatory cell infiltration and mitochondrial injury occurred in renal tissue. AA-I exposure resulted in a substantial rise in the levels of BAX, Ccaspase-9, Cleaved Caspase-9, Caspase-3, Cleaved Caspase-3 and a significant decrease in mRNA and protein expression levels of Bcl-2, SIRT1, Nrf2, NQO1, HO-1 and Keap1. However, these changes were reversed by CUR intervention. In summary, AA-I exposure caused mitochondrial dysfunction and triggered apoptosis through the oxidative stress pathway. However, CUR could reduce AA-I-induced renal injury by activating the SIRT1/Nrf2/HO-1 signaling pathway.

Aristolochic Acid Nephropathy: A Novel Suppression Strategy of Carbon Dots Derived from Astragali Radix Carbonisata

Despite strict restrictions on the use of aristolochic acids (AAs)-containing merchandise or drugs in many countries, a substantial amounts of occurrences aristolochic acid nephropathy (AAN) had been accounted worldwide. Clinically, there is no effective incurable therapy regimen to reverse the progression of AAN. Although carbon dots have shown surprising bioactivity, research on the acute kidney injury caused by AAs is lacking. Here, a novel biomass-carbon dots from Astragali Radix (AR) as precursors was synthesized through one-step pyrolysis treatment. The ARC-carbon dots (ARC-CDs) was demonstrated in detail for its inhibitory effect on aristolochic acid nephropathy in a mice model. The indexes of inflammatory cytokines as well as oxidative stress were significantly reduced by the ARC-CDs in kidney tissue cells. Additionally, the ARC-CDs administration resulted in a large decrease in positive apoptotic cells according to TUNEL labeling and western blotting, which may be connected to the ARC-CDs’ modulation of the protein in the Akt/Mdm2/p53 signaling pathway. These findings show that ARC-CDs have remarkable anti-inflammatory, antioxidant, and anti-apoptotic capabilities against acute kidney injury spurred by aristolochic acids via the AKT/Mdm2/p53 signaling pathway.

Oral subacute nephrotoxicity of aristololactam I in rats

Aristolactams (ALs) have been recognized as one kind of metabolites of aristolochic acids (AAs), the nephrotoxic components of Aristolochiaceae plants, and are more widely distributed than AAs in herbal medicines. This study evaluated the oral subacute nephrotoxicity of aristolactam I (AL I), a representative compound of ALs. AL I was intragastrically administered to rats at 20 mg·kg^-1·d^-1 for 10 or 20 days, with aristolochic acid I (AA I) used as positive control at the same dose. After 10-day treatment, AL I led to a significant increase in early renal injury-related indices in urine and obvious histopathological lesions in kidneys, including degeneration of tubular epithelial cells, inflammatory cell infiltration and fibrosis. The lesions induced by AL I were significantly aggravated after 20-day exposure. However, AL I induced less histopathological damage in kidneys than AA I in both 10- and 20-day groups. Our results indicated that oral AL I caused nephrotoxicity by inducing oxidative stress, inflammation, and overactivation of the complement system as AA I did. Three detected apoptosis-associated indicators were not affected by AL I but remarkably increased by AA I. In summary, oral AL I induced evident renal damage in rats after only 10 days of treatment, and the damage was aggravated after 20 days. However, AL I was obviously less nephrotoxic than AA I via oral gavage.

Total flavonoids in Epimedium koreanum Nakai alleviated chronic renal failure via promoting AMPK activation

Chronic renal failure (CRF) is a result of the progression of chronic kidney diseases (CKD), a global health problem with a high cost of treatment and no ideal therapy. The aim of this study is to evaluate the pharmacological efficacy of the total flavonoids in Epimedium koreanum Nakai (TFE), a dietary supplement, against CRF and to determine the mechanism of actions. An adenine-induced CRF rat model and a TGF-β1 induced human kidney proximal tubule epithelial (HK-2) cell based in vitro renal fibrosis model were established and used to evaluate TFE's efficacy. Renal hemodynamics, biochemical indexes, inflammatory cytokines, histopathology and the reactive oxygen species (ROS) levels were determined to evaluate the efficacy of TFE on CRF. NMR-based metabolomics, immunohistochemical (IHC) staining, immunofluorescence (IF) staining, quantitative real time-PCR (qRT-PCR) and western blotting were conducted to determine the mechanism. The results showed that TFE had a significant effect on CRF at 150 mg kg^-1 d^-1 and could significantly alleviate renal fibrosis in the animal model. Twelve potential biomarkers, which mainly involve energy metabolism pathways, for CRF were identified using the metabolomics approach. The mechanism study suggested that TFE regulated AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) and AMPK/silent information regulator 1 (SIRT1)/nuclear factor kappa-B (NF-κB) signaling pathways. Furthermore, the effect of TFE was inhibited by compound C in the in vitro experiment, which also confirmed the above conclusion.

microRNA-181a promotes the oncogene S100A2 and enhances papillary thyroid carcinoma growth by mediating the expression of histone demethylase KDM5C

BACKGROUND AND PURPOSE

Papillary thyroid carcinoma (PTC) is an endocrine malignancy. Increasing evidence highlights microRNAs (miRNAs) as important participants in PTC. Here, we investigated the role of miR-181a in PTC.

METHODS

A microarray-based analysis was performed to identify the differential expression of miR-181a in PTC, which was validated with RT-qPCR. Protein expression of the proliferation-related factor Ki-67 and apoptosis- and migration-related factors in PTC was assessed with immunoblot analysis. A dual-luciferase reporter gene assay was adopted to verify the relationship between miR-181a and lysine demethylase 5C (KDM5C). Chromatin immunoprecipitation (ChIP) was used to detect the level of the H3K4me3 modification on S100 calcium-binding protein A2 (S100A2). Cell viability, apoptosis, and invasion and migration abilities were evaluated by Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assays, respectively. The in vitro results were verified in in vivo nude mouse models.

RESULTS

miR-181a was highly expressed in PTC tissues and cell lines. Silencing miR-181a repressed the proliferation and migration of PTC cells. KDM5C was identified as the target gene of miR-181a and represses S100A2 expression through histone demethylation to diminish the migration and proliferation of PTC cells. miR-181a depletion suppressed tumor growth.

CONCLUSION

Collectively, these results suggest that highly expressed miR-181a promotes the proliferation of PTC cells by increasing the expression of the oncogene S100A2. This study contributes to the advancement of miR-181a-targeted therapeutics.

Analysis of aristolochic acid I in mouse serum and tissues by using magnetic solid-phase extraction and UHPLC-MS/MS

A method combining magnetic solid-phase extraction (MSPE) and ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the analysis of aristolochic acids I (AAI) in mouse serum and tissues. The magnetic covalent organic frameworks (MNP@COF)-based MSPE exhibited high adsorption capacity towards AAI (93.1 mg/g) in optimal conditions. After MSPE extraction, AAI was separated with C18 column using gradient elution and quantified (m/z 342.21 → 298.13) by UHPLC-MS/MS with monitor reaction monitoring (MRM) mode. This MSPE-based UHPLC-MS/MS method was validated with respected to lower limit of quantification (LLOQ), linearity, recovery, precision and accuracy of intra- and inter-day, and matrix effect. Good calibration linearities at the range of 1-500 ng/L for AAI in biological matrices (serum, kidney, and liver) with high correlation coefficient (R²) > 0.9970, and high enrichment factors (mean values from 1038 to 1045) were obtained. This method was highly sensitive to determine AAI with LLOQ within the range of 4.62-5.24 ng/L in extracted serum, kidney, and liver samples. Recoveries at 5, 50, 100 and 300 ng/L in biological samples ranged from 93.2 to 104.0%, and intra- and inter day accuracy and precision (defined as bias and coefficient of variation, respectively) were below ± 15%. The method was successfully applied in the analysis of biological samples collected from mice exposed with AAI with concentrations range of 0.007-0.041 μg/L for consecutive four days. The established method might be applied for the investigation of risk assessment and toxicity induced by long-time use of AAI-containing herbs or dietary supplements.

Rapamycin protects against aristolochic acid nephropathy in mice by potentiating mammalian target of rapamycin‑mediated autophagy

Autophagy serves a crucial role in the etiology of kidney diseases, including drug‑induced renal impairment, inherited kidney disease, diabetic nephropathy and aristolochic acid nephropathy (AAN) and is, therefore, a potential target for treatment. We previously demonstrated that rapamycin could attenuate AAN in mice; however, the underlying mechanism remains to be elucidated. Therefore, whether the renal protective effect of rapamycin (an autophagy activator) is related to autophagy in aristolochic acid (AA)‑treated mice was of particular interest. The pathophysiological roles of rapamycin were investigated in AA‑induced nephrotoxicity in mice and the mechanisms of rapamycin action were explored by evaluating the modulation of autophagy in rapamycin‑treated mice and cultured renal tubular epithelial cells. Supplementation with rapamycin reversed AA‑induced kidney injury in mice and improved AA‑induced autophagy damage in vivo and in vitro. Mechanistically, rapamycin inhibited the renal expression of phosphorylated (p‑)mammalian target of rapamycin (mTOR) and p‑ribosomal S6 protein kinase 1, which in turn activated renal autophagy and decreased apoptosis, probably by removing AA‑elicited damaged mitochondria and misfolded proteins. The findings of the present study demonstrated that rapamycin protects against AA‑induced nephropathy by activating the mTOR‑autophagy axis and suggested that rapamycin may be a promising pharmacological target for the treatment of AAN.

Targeting autophagy using saponins as a therapeutic and preventive strategy against human diseases

Autophagy is a ubiquitous mechanism for maintaining cellular homeostasis through the degradation of long-lived proteins, insoluble protein aggregates, and superfluous or damaged organelles. Dysfunctional autophagy is observed in a variety of human diseases. With advanced research into the role that autophagy plays in physiological and pathological conditions, targeting autophagy is becoming a novel tactic for disease management. Saponins are naturally occurring glycosides containing triterpenoids or steroidal sapogenins as aglycones, and some saponins are reported to modulate autophagy. Research suggests that saponins may have therapeutic and preventive efficacy against many autophagy-related diseases. Therefore, this review comprehensively summarizes and discusses the reported saponins that exhibit autophagy regulating activities. In addition, the relevant signaling pathways that the mechanisms involved in regulating autophagy and the targeted diseases were also discussed. By regulating autophagy and related pathways, saponins exhibit bioactivities against cancer, neurodegenerative diseases, atherosclerosis and other cardiac diseases, kidney diseases, liver diseases, acute pancreatitis, and osteoporosis. This review provides an overview of the autophagy-regulating activity of saponins, the underlying mechanisms and potential applications for managing various diseases.