The water-soluble triptolide derivative PG490-88 protects against cisplatin-induced acute kidney injury

Efficacy of Trametinib in Alleviating Cisplatin-Induced Acute Kidney Injury: Inhibition of Inflammation, Oxidative Stress, and Tubular Cell Death in a Mouse Model

Cisplatin, a platinum-based chemotherapeutic, is effective against various solid tumors, but its use is often limited by its nephrotoxic effects. This study evaluated the protective effects of trametinib, an FDA-approved selective inhibitor of mitogen-activated protein kinase kinase 1/2 (MEK1/2), against cisplatin-induced acute kidney injury (AKI) in mice. The experimental design included four groups, control, trametinib, cisplatin, and a combination of cisplatin and trametinib, each consisting of eight mice. Cisplatin was administered intraperitoneally at a dose of 20 mg/kg to induce kidney injury, while trametinib was administered via oral gavage at 3 mg/kg daily for three days. Assessments were conducted 72 h after cisplatin administration. Our results demonstrate that trametinib significantly reduces the phosphorylation of MEK1/2 and extracellular signal-regulated kinase 1/2 (ERK1/2), mitigated renal dysfunction, and ameliorated histopathological abnormalities. Additionally, trametinib significantly decreased macrophage infiltration and the expression of pro-inflammatory cytokines in the kidneys. It also lowered lipid peroxidation by-products, restored the reduced glutathione/oxidized glutathione ratio, and downregulated NADPH oxidase 4. Furthermore, trametinib significantly inhibited both apoptosis and necroptosis in the kidneys. In conclusion, our data underscore the potential of trametinib as a therapeutic agent for cisplatin-induced AKI, highlighting its role in reducing inflammation, oxidative stress, and tubular cell death.

Protective effects of triptolide against oxidative stress in retinal pigment epithelium cells via the PI3K/AKT/Nrf2 pathway: a network pharmacological method and experimental validation

PURPOSE

Among aging adults, age-related macular degeneration (AMD), is a prevalent cause of blindness. Nevertheless, its progression may be halted by antioxidation in retinal pigment epithelium (RPE). The primary effective constituent of Tripterygium wilfordii Hook. F., triptolide (TP), has demonstrated anti-inflammatory, antiproliferative, and antioxidant properties. The mechanics of the protective effect of triptolide against the oxidative damage in retinal pigment epithelial (RPE) were assessed in this study.

METHODS

ARPE-19 cells were pretreated with TP, and then exposed to sodium iodate (SI). First, cell viability was assessed using CCK-8. Subsequently, we measured indicators for cell oxidation including reactive oxygen species (ROS), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA). Then, we used network pharmacological analysis and molecular docking to explore the signaling pathway of TP. Last, we used western blot, ELISA, and immunofluorescence assays to clarify the potential mechanistic pathways.

RESULTS

The network pharmacology data suggested that TP may inhibit AMD by regulating the PI3K/Akt signaling pathway. Experimental results showed that the potential mechanism is that it regulates the PI3K/Akt pathway and promotes Nrf2 phosphorylation and activation, thereby raising the level of antioxidant factors (HO-1, NQO1) and reducing the generation of ROS, which inhibit oxidative damage.

CONCLUSION

Our findings suggested that the effect of TP on SI-exposed RPE cells principally relies on the regulation of oxidative stress through the PI3K/Akt/Nrf2 signaling pathway.

Natural products applied in acute kidney injury treatment: polymer matters

Acute kidney injury (AKI) is a global health threat due to its high morbidity and mortality. There is still a lack of effective therapeutic methods to deal with AKI clinically. Natural products with outstanding accessibility and bioactivity are potential candidates for AKI treatment. Natural product-based prodrugs or nano-structures with improved properties are frequently fabricated for maximizing bioavailability and decreasing side effects, in which natural polymers are selected as carriers, or natural drugs are loaded as cargos on designed polymers. In this review, the etiologies of AKI are briefly presented, and emerging natural products delivered rationally for AKI therapy, as either carriers or cargos, are both introduced. Moreover, the challenges of the future development of nature-based nanodrugs or prodrugs for AKI have also been discussed.

Madecassoside ameliorates cisplatin-induced nephrotoxicity by inhibiting activation of the mitogen activated protein kinase pathway

Nephrotoxicity is a major side effect of cisplatin. Apoptosis, oxidative stress, inflammation, and the MAPK signaling pathway activation are concerned with the pathophysiology of cisplatin-induced acute kidney injury (AKI). Madecassoside (MA), an active constituent of Centella asiatica, has anti-oxidative and anti-inflammatory effects. The present research aim to investigate the underlying protective mechanisms of MA on cisplatin nephrotoxicity. Pretreatment of mice with MA markedly ameliorated cisplatin-induced renal tubular cell injury evidenced by the improvement of kidney function and kidney morphology and blocked upregulation of kidney injury biomarkers (kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL)). Cisplatin-induced renal cell apoptosis, inflammation, and oxidative stress were also prevented by MA treatment. Consistent with the in vivo results, MA pretreatment attenuated cisplatin-induced renal cell apoptosis, oxidative stress, and inflammation. Transcriptome analysis using RNA-sequencing suggested that the MAPK signaling pathway was the most affected, and MA could inhibit cisplatin-induced MAPK signaling pathway activation in vivo and in vitro. In summary, MA treatment ameliorated cisplatin-induced renal tubular damage possibly by decreasing activation of the MAPK signaling pathway, suggesting its potential for the treatment of AKI.

Ojeoksan Ameliorates Cisplatin-Induced Acute Kidney Injury in Mice by Downregulating MAPK and NF-κB Pathways

Acute kidney injury (AKI) is a major side effect of cisplatin, a crucial anticancer agent. Therefore, it is necessary to develop drugs to protect against cisplatin-induced nephrotoxicity. Ojeoksan (OJS), a traditional blended herbal prescription, is mostly used in Korea; however, there are no reports on the efficacy of OJS against cisplatin-induced AKI. To investigate the reno-protective effect of OJS on AKI, we orally administered 50, 100, and 200 mg/kg of OJS to mice 1 h before intraperitoneal injection with 20 mg/kg of cisplatin. OJS inhibited the increase of blood urea nitrogen (BUN) and serum creatinine (SCr) levels and reduced histological changes in the kidney, like loss of brush borders, renal tubular necrosis, and cast formation. Administration of OSJ reduced the levels of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. In addition, OJS inhibited the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways in cisplatin-induced AKI. These results suggest that OJS attenuates cisplatin-induced AKI by downregulating the MAPK and NF-κB pathways.

Triptolide Suppresses NF-κB-Mediated Inflammatory Responses and Activates Expression of Nrf2-Mediated Antioxidant Genes to Alleviate Caerulein-Induced Acute Pancreatitis

Triptolide (TP), the main active ingredient of Tripterygium wilfordii Hook.f., displays potent anti-inflammatory, antioxidant, and antiproliferative activities. In the present study, the effect of TP on acute pancreatitis and the underlying mechanisms of the disease were investigated using a caerulein-induced animal model of acute pancreatitis (AP) and an in vitro cell model. In vivo, pretreatment with TP notably ameliorated pancreatic damage, shown as the improvement in serum amylase and lipase levels and pancreatic morphology. Meanwhile, TP modulated the infiltration of neutrophils and macrophages (Ly6G staining and CD68 staining) and decreased the levels of proinflammatory factors (TNF-α and IL-6) through inhibiting the transactivation of nuclear factor-κB (NF-κB) in caerulein-treated mice. Furthermore, TP reverted changes in oxidative stress markers, including pancreatic glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA), in acute pancreatitis mice. Additionally, TP pretreatment inhibited intracellular reactive oxygen species (ROS) levels via upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and Nrf2-regulated redox genes expression (HO-1, SOD1, GPx1 and NQO1) in vitro. Taken together, our data suggest that TP exert protection against pancreatic inflammation and tissue damage by inhibiting NF-κB transactivation, modulating immune cell responses and activating the Nrf2-mediated antioxidative system, thereby alleviating acute pancreatitis.

TRPA1 promotes cisplatin-induced nephrotoxicity through inflammation mediated by the MAPK/NF-κB signaling pathway

Background

The nephrotoxicity induced by cisplatin (DDP) has been a severe obstacle for its clinical use in anticancer treatment. The apoptosis and inflammation induced by DDP are the main causes of the nephrotoxicity. Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation ligand-gated channel that is involved in the inflammation progress.

Methods

The apoptosis, inflammation, MAPK/NF-κB signaling pathway, and TRPA1 expression were assessed after HEK293 cells had been induced by DDP, and the role of TRPA1 in apoptosis and inflammation of DDP-induced HEK293 cells treated with TRPA1 antagonist HC-030031 was also evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), flow cytometry, and western blot assays.

Results

The cell viability was reduced by DDP in both a time-dependent and dose-dependent manner with a minimal cytotoxic concentration of 10 μM. Moreover, DDP induced an enhancement of the apoptosis and inflammation in a dose-dependent manner, as indicated by the increase of the relative protein level of cleaved-caspase3 (cleaved-cas3), the cleavage product of caspase-3 substrate poly-ADP-ribose polymerase (cleaved-PARP) and inducible nitric oxide synthase (iNOS), and the messenger RNA (mRNA) expression level of interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and interferon-γ (INF-γ). Additionally, DDP treatment increased the protein phosphorylation expression of IKKβ, JNK, ERK, and p38 in a dose-dependent manner, which was antagonized by the treatment of NF-κB-specific inhibitor BAY 11-7082 and pan-MAPK inhibitor U0126. It was also found that DDP upregulated the expression of TRPA1 at both the mRNA and protein levels in a dose-dependent manner. Besides, block of TRPA1 with HC-030031 relieved the apoptosis, diminished the level of IL-1β, IL-6, TNF-α, and INF-γ, reduced the level of cleaved-cas3, cleaved-PARP, and iNOS, decreased the p-IKKβ, p-JNK, p-ERK, and p-p38 expression, and enhanced the expression of IκBα.

Conclusions

Taken together, these results indicate that TRPA1 regulates DDP-induced nephrotoxicity via inflammation mediated by the MAPK/NF-κB signaling pathway in HEK293 cells.

Mechanism Involved in Fortification by Berberine in CDDP-Induced Nephrotoxicity

BACKGROUND

The activation of Nrf2/HO-1 pathway has been shown to protect against cisplatin- induced nephrotoxicity by reducing oxidative stress. Berberine (Ber), an isoquinoline alkaloid, has demonstrated antioxidant, anti-inflammatory and anti-apoptotic activities in various experimental models.

AIM

To check the effect of Ber on cisplatin-induced nephrotoxicity and to explore the involved mechanism.

METHODS

Adult male Wistar rats were divided into 6 groups: Normal, cisplatin-control, treatment groups and per se group. Normal saline and Ber (20, 40 and 80 mg/kg; p.o.) was administered to rats for 10 days. A single intraperitoneal injection of cisplatin (8 mg/kg) was injected on 7th day to induced nephrotoxicity. On 10th day, rats were sacrificed, the kidney was removed and stored for the estimation of various parameters.

RESULTS

As compared to cisplatin-control group, Ber pretreatment improved renal function system and preserved renal architecture. It also diminished oxidative stress by upregulating the expression of Nrf2/HO-1 proteins. In addition, Ber attenuated the cisplatin mediated inflammation and apoptosis. Furthermore, it also reduced the phosphorylation of p38/JNK and PARP/Beclin-1 expression in the kidney.

CONCLUSION

Ber attenuated renal injury by activating Nrf2/HO-1 and inhibiting JNK/p38MAPKs/ PARP/Beclin-1 expression which prevented oxidative stress, inflammation, apoptosis and autophagy in renal tissue.

Triptolide: pharmacological spectrum, biosynthesis, chemical synthesis and derivatives

Triptolide, an abietane-type diterpenoid isolated from Tripterygium wilfordii Hook. F., has significant pharmacological activity. Research results show that triptolide has obvious inhibitory effects on many solid tumors. Therefore, triptolide has become one of the lead compounds candidates for being the next "blockbuster" drug, and multiple triptolide derivatives have entered clinical research. An increasing number of researchers have developed triptolide synthesis methods to meet the clinical need. To provide new ideas for researchers in different disciplines and connect different disciplines with researchers aiming to solve scientific problems more efficiently, this article reviews the research progress made with analyzes of triptolide pharmacological activity, biosynthetic pathways, and chemical synthesis pathways and reported in toxicological and clinical studies of derivatives over the past 20 years, which have laid the foundation for subsequent researchers to study triptolide in many ways.

Loganin Attenuates the Severity of Acute Kidney Injury Induced by Cisplatin through the Inhibition of ERK Activation in Mice

Cisplatin is the most widely used chemotherapeutic agent. However, it often causes nephrotoxicity, which results in acute kidney injury (AKI). Therefore, we urgently need a drug that can reduce the nephrotoxicity induced by cisplatin. Loganin is a major iridoid glycoside isolated from Corni fructus that has been used as an anti-inflammatory agent in various pathological models. However, the renal protective activity of loganin remains unclear. In this study, to examine the protective effect of loganin on cisplatin-induced AKI, male C57BL/6 mice were orally administered with loganin (1, 10, and 20 mg/kg) 1 h before intraperitoneal injection of cisplatin (10 mg/kg) and sacrificed at three days after the injection. The administration of loganin inhibited the elevation of blood urea nitrogen (BUN) and creatinine (CREA) in serum, which are used as biomarkers of AKI. Moreover, histological kidney injury, proximal tubule damages, and renal cell death, such as apoptosis and ferroptosis, were reduced by loganin treatment. Also, pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, reduced by loganin treatment. Furthermore, loganin deactivated the extracellular signal-regulated kinases (ERK) 1 and 2 during AKI. Taken together, our results suggest that loganin may attenuate cisplatin-induced AKI through the inhibition of ERK1/2.

Isoquercitrin Ameliorates Cisplatin-Induced Nephrotoxicity Via the Inhibition of Apoptosis, Inflammation, and Oxidative Stress

Cisplatin is extensively used and is highly effective in clinical oncology; nevertheless, nephrotoxicity has severely limited its widespread utility. Isoquercitrin (IQC), a natural flavonoid widely found in herbage, is well known and recognized for its antioxidant, anti-inflammatory, and anti-apoptotic properties. However, the potential effects and mechanism of IQC in cisplatin-induced acute kidney diseases remain unknown. In this study, we postulated the potential effects and mechanism of IQC upon cisplatin exposure in vivo and in vitro. For the in vivo study, C57BL/6J mice were pretreated with IQC or saline (50 mg/kg/day) by gavage for 3 days before cisplatin single injection (25 mg/kg). Renal function, apoptosis, inflammation, oxidative stress and p-ERK were measured to evaluate kidney injury. In vitro, mouse proximal tubular cells (mPTCs) and human proximal tubule epithelial cell line (HK2) were pretreated with or without IQC (80 μM for mPTCs and 120 μM for HK2) for 2 h and then co-administrated with cisplatin for another 24 h. Apoptosis, inflammation, ROS and p-ERK of cells were also measured. In vivo, IQC administration strikingly reduced cisplatin-induced nephrotoxicity as evidenced by the improvement in renal function (serum creatinine and blood urea nitrogen), kidney histology (PAS staining), apoptotic molecules (cleaved caspase-3, caspase-8, Bax and Bcl-2), inflammatory cytokines (IL-1β, IL-6, TNF-α, and COX-2), oxidative stress (MDA and total glutathione) and p-ERK. In line with in vivo findings, IQC markedly protected against cisplatin-induced cell injury in mPTCs and HK2 cells. Collectively, these findings demonstrated that IQC administration could significantly protect against cisplatin nephrotoxicity possibly through ameliorating apoptosis, inflammation and oxidative stress accompanied by cross talk with p-ERK. Furthermore, IQC may have potential therapeutic uses in the treatment of cisplatin-induced acute kidney injury.

SIRT2 is involved in cisplatin-induced acute kidney injury through regulation of mitogen-activated protein kinase phosphatase-1

BACKGROUND

Activation of mitogen-activated protein kinase phosphatase-1 (MKP-1), a dual-specificity protein phosphatase, regulates mitogen-activated protein kinase signaling. C-Jun N-terminal kinase (JNK) and p38 are activated in cisplatin-induced renal injury. However, the change of MKP-1 expression in cisplatin-induced renal injury and the regulatory effect of sirtuin 2 (SIRT2), a nicotinamide adenine dinucleotide-dependent deacetylase, on MKP-1 remains unknown.

METHODS

To address these issues, we used constitutional Sirt2 knockout (KO) mice, transgenic (TG) mice with increased expression of SIRT2 specifically in proximal tubular epithelial cellsand wild-type (WT) mice. Cisplatin nephrotoxicity was induced by intraperitoneal injection of cisplatin.

RESULTS

MKP-1 expression in the kidney was decreased after cisplatin treatment. Cisplatin-induced downregulation of MKP-1 was reversed in Sirt2 KO mice kidney and further decreased in Sirt2 TG mice kidney. We observed similar phenomenon with SIRT2-knockdown or SIRT2-overexpressed tubular epithelial cells. Phosphorylation of p38 and JNK, a downstream signal pathway of MKP-1, increased in WT mice kidney following treatment with cisplatin. A decrease in SIRT2 suppressed cisplatin-induced phosphorylation of p38 and JNK in kidney and tubular epithelial cells. Overexpression of SIRT2 further increased phosphorylation of p38 and JNK in kidney and tubular epithelial cells. Acetylation of MKP-1 was significantly increased in SIRT2-knockdown cells and decreased in SIRT2-overexpressed cells after cisplatin stimulation. Sirt2 KO mice and Sirt2 TG mice showed amelioration and aggravation of renal injury, apoptosis, necroptosis and inflammation induced by cisplatin.

CONCLUSION

Our data show that SIRT2 is associated with cisplatin-induced renal injury through regulation of MKP-1 expression.

The effect of MEK1/2 inhibitors on cisplatin-induced acute kidney injury (AKI) and cancer growth in mice

In a clinically-relevant model of 4 week, low-dose cisplatin-induced AKI, mice were injected subcutaneously with non small cell lung cancer (NSCLC) cells that harbor an activating Kirsten rat sarcoma viral oncogene homolog (KRAS)^G12V mutation. Phospho extracellular signal-regulated kinase1/2 (pERK1/2) expression in kidney and tumors was decreased by the MEK1/2 inhibitors, U0126 and trametinib, that potently inhibit pERK1/2. U0126 resulted in a significant improvement in kidney function, acute tubular necrosis (ATN) and tubular cell apoptosis in mice with AKI. Genes that were significantly decreased by U0126 were heat shock protein 1, cyclin-dependent kinase 4 (CDK4) and stratifin (14-3-3σ). U0126 resulted in a significant decrease in tumor weight and volume and significantly increased the chemotherapeutic effect of cisplatin. Trametinib, a MEK1/2 inhibitor that is FDA-approved for the treatment of cancer, did not result in functional protection against AKI or worse AKI, but dramatically decreased tumor growth more than cisplatin. Smaller tumors in cisplatin or MEK1/2 inhibitor-treated mice were not related to changes in microtubule-associated proteins 1A/1B light chain 3B (LC3-II), p62, cleaved caspase-3, granzyme B, or programmed death-ligand 1 (PD-L1). In summary, despite ERK inhibition by both U0126 and trametinib, only U0126 protected against AKI suggesting that the protection against AKI by U0126 was due to an off-target effect independent of ERK inhibition. The effect of U0126 to decrease AKI may be mediated by inhibition of heat shock protein 1, CDK4 or stratifin (14-3-3σ). Trametinib was more effective than cisplatin in decreasing tumor growth, but unlike cisplatin, trametinib did not cause AKI.

Recent Advances in Models, Mechanisms, Biomarkers, and Interventions in Cisplatin-Induced Acute Kidney Injury

Cisplatin is a widely used chemotherapeutic agent used to treat solid tumours, such as ovarian, head and neck, and testicular germ cell. A known complication of cisplatin administration is acute kidney injury (AKI). The development of effective tumour interventions with reduced nephrotoxicity relies heavily on understanding the molecular pathophysiology of cisplatin-induced AKI. Rodent models have provided mechanistic insight into the pathophysiology of cisplatin-induced AKI. In the subsequent review, we provide a detailed discussion of recent advances in the cisplatin-induced AKI phenotype, principal mechanistic findings of injury and therapy, and pre-clinical use of AKI rodent models. Cisplatin-induced AKI murine models faithfully develop gross manifestations of clinical AKI such as decreased kidney function, increased expression of tubular injury biomarkers, and tubular injury evident by histology. Pathways involved in AKI include apoptosis, necrosis, inflammation, and increased oxidative stress, ultimately providing a translational platform for testing the therapeutic efficacy of potential interventions. This review provides a discussion of the foundation laid by cisplatin-induced AKI rodent models for our current understanding of AKI molecular pathophysiology.

Targeting pro-senescence mitogen activated protein kinase (Mapk) enzymes with bioactive natural compounds

Aging is a multifactorial universal process characterized by a gradual decrease in physiological and biochemical functions. Given that life expectancy is on the rise, a better understanding of molecular mechanisms of the aging process is necessary in order to develop anti-aging interventions. Uncontrolled cellular senescence promotes persistent inflammation and accelerates the aging process by decreasing tissue renewal, repair and regeneration. Senescence of immune cells, immunesenescence, is another hallmark of aging. Targeting pro-senescent enzymes increases survival and therefore the lifespan. Although the upregulation of Mitogen Activated Protein Kinases (MAPK) enzymes in aging is still controversial, increasing evidence shows that dysregulation of those enzymes are associated with biological processes that contribute to aging such as irreversible senescence. In this manuscript components of the MAPK pathway will be summarized, including extracellular signal-regulated kinase 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38, as well as natural flavonoids, phenolic and diterpenoids with anti-senescence activity that shows positive effects on longevity and MAPK inhibition. Although more studies using additional aging models are needed, we suggest that these selected natural bioactive compounds that regulate MAPK enzymes and reduce senescent cells can be potentially used to improve longevity and prevent/treat age-related diseases.

Application of Herbal Traditional Chinese Medicine in the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid loss of renal function, which may further develop into chronic kidney damage (CKD) or even end-stage renal disease (ESRD). AKI is a global health problem associated with high morbidity and costly treatments, and there is no specific or effective strategy to treat AKI. In recent years, Traditional Chinese Medicine (TCM) has attracted more attention, with lines of evidence showing that application of TCM improved AKI, and the mechanisms of action for some TCMs have been well illustrated. However, reviews summarizing the progress in this field are still lacking. In this paper, we reviewed TCM preparations and TCM monomers in the treatment of AKI over the last 10 years, describing their renal protective effects and mechanisms of action, including alleviating inflammation, programmed cell death, necrosis, and reactive oxygen species. By focusing on the mechanisms of TCMs to improve renal function, we provide effective complementary evidence to promote the development of TCMs to treat AKI. Moreover, we also summarized TCMs with nephrotoxicity, which provides a more comprehensive understanding of TCMs in the treatment of AKI. This review may provide a theoretical basis for the clinical application of TCMs in the future.

Kidney-targeted triptolide-encapsulated mesoscale nanoparticles for high-efficiency treatment of kidney injury

Insolubility and toxicity of TP restrict clinical applications in renal diseases. Here, TP-encapsulated mesoscale nanoparticles offer a new therapeutic strategy for renal diseases due to good biocompability, kidney targeting and slow release.

PG490-88, a derivative of triptolide, suppresses ischemia/reperfusion-induced lung damage by maintaining tight junction barriers and targeting multiple signaling pathways

Previous studies demonstrated that triptolide (PG490) has many anti-inflammatory and immunosuppressive effects. However, little is known about the effect of PG490-88 (a water-soluble derivative of triptolide) on ischemia/reperfusion (I/R)-induced acute lung injury. We assessed the effects of PG490-88 on I/R-induced acute lung injury in rats and on hypoxia/reoxygenation (H/R) in a line of murine epithelial cells. Isolated perfused rat lungs were subjected to 40 min of ischemia, followed by 60 min of reperfusion to induce I/R injury. Induction of I/R led to lung edema, elevated pulmonary arterial pressure, histological evidence of lung inflammation, oxidative stress, and increased levels of TNF-α and CINC-1 in bronchoalveolar lavage fluid. PG490-88 significantly suppressed all of these responses. Additionally, induction of I/R reduced the expression of claudin-4, occludin, and ZO-1, and increased apoptosis in lung tissue. PG490-88 also significantly suppressed these effects. I/R reduced the levels of IκB-α and MKP-1, and increased the levels of nuclear NF-κB and mitogen-activated protein kinase in lung tissue, and PG490-88 suppressed these effects. In vitro studies using mouse lung alveolar epithelial cells indicated that H/R increased the levels of phosphorylated p65 and MIP-2, but decreased the level of IκB-α. PG490-88 also suppressed these effects. In I/R damaged lungs, PG490-88 suppresses the inflammatory response, disruption of tight junction structure, and apoptosis. PG490-88 has the potential as a prophylactic agent to prevent I/R-induced lung injury.

Vitamin D attenuates gentamicin-induced acute renal damage via prevention of oxidative stress and DNA damage

Background:

Despite being one of the most nephrotoxic drugs, gentamicin (GM) remains a mainstay as a first-choice agent in a vast variety of clinical situations owing to its superlative efficiency as a broad-spectrum antibiotic in treating several life-threatening bacterial infections. This urgently calls for the need for in-depth analysis of the mechanisms governing GM-induced nephrotoxicity and entails the necessity of presenting novel protective agents capable of ameliorating those renal deleterious effects. The reactive oxygen species and redox-sensitive transcription factors in GM-induced nephrotoxicity have recently called attention.

Purpose:

This study has been designed to shed light on the possible mechanisms of GM-induced nephrotoxicity and to provide a consensus set of histopathological, immunohistochemical, genetic and biochemical parameters elucidating the protective role of vitamin D against this nephrotoxicity.

Methods:

Twenty-four adult male albino rats were equally divided into four groups: group I (control group), group II (GM), group III (GM + vitamin D) and group IV (vitamin D only). Kidney function tests, histopathological examination, gene expression of nuclear factor 2, nuclear factor kappa beta (NF-κB) and western blot of NF-κB p65, assessment of glutathione peroxidase and nicotinamide adenine dinucleotide phosphate oxidase (NADPH) oxidase by ELISA, as well as immunohistochemical evaluation of inducible nitric oxide, malondialdehyde, 8-hydroxy 2 deoxyguanine and vitamin D receptor, have been carried out.

Results:

The kidney function deterioration, tissue oxidative stress development and the histopathological changes induced by GM were significantly attenuated by vitamin D administration.

Conclusion:

Vitamin D attenuates GM nephrotoxicity through its antioxidant properties and prevention of DNA damage.

Necrostatin-1 Attenuates Cisplatin-Induced Nephrotoxicity Through Suppression of Apoptosis and Oxidative Stress and Retains Klotho Expression

Aim: Cisplatin is an effective chemotherapeutic drug, but the application in clinical is greatly limited by its nephrotoxicity. Necrostatin-1 (Nec-1), an inhibitor of RIP1 kinase, has been reported to inhibit RIP-mediated necroptosis. The aim of this study is to detect the protective effects of Nec-1 on the nephrotoxicity of cisplatin and to investigate its renoprotection mechanism. Methods: 8-week-old male C57BL/6 mice were randomly assigned into four groups: Control, Nec-1, Cisplatin, and Cisplatin+Nec-1. Mice were treated with cisplatin with or without Nec-1 pre-treatment. Renal function, histological changes, necroptosis, and apoptotic markers were investigated. NFκB pathway related proteins, proinflammatory cytokines, oxidative stress markers, renal Klotho, and autophagy-related proteins levels were also examined. Results: Renal function and histological data displayed that the treatment with Nec-1 significantly attenuates cisplatin-induced renal damage. The expression of RIPK1/RIPK3/MLKL were significantly enhanced in cisplatin group as compared to the control group (p < 0.05) and was significantly reduced by pre-treatment of Nec-1 (p < 0.05). The level of stress and apoptosis-related protein, including p-JNK, p-c-Jun, p-p38, Bax/Bcl-2 ratio, and caspase-3 showed the similar trend. Pre-treatment with Nec-1 inhibit NFκB signaling, reduced proinflammatory cytokines and oxidative stress, up-regulated renal Klotho, and autophagy-related proteins levels. Conclusion: Our results suggest that Nec-1 could be a potential therapeutic drug against the cisplatin-induced nephrotoxicity through its anti-necroptosis, anti-apoptotic, anti-inflammatory anti-oxidant and retain Klotho expression and activate autophagy effects in the kidney.

Triptolide induces Sertoli cell apoptosis in mice via ROS/JNK-dependent activation of the mitochondrial pathway and inhibition of Nrf2-mediated antioxidant response

Triptolide (TP), an oxygenated diterpene, has a variety of beneficial pharmacodynamic activities but its clinical applications are restricted due to severe testicular injury. This study aimed to delineate the molecular mechanisms of TP-induced testicular injury in vitro and in vivo. TP (5-50000 nmol/L) dose-dependently decreased the viability of TM4 Sertoli cells with an IC₅₀ value of 669.5-269.45 nmol/L at 24 h. TP (125, 250, and 500 nmol/L) dose-dependently increased the accumulation of ROS, the phosphorylation of JNK, mitochondrial dysfunction and activation of the intrinsic apoptosis pathway in TM4 cells. These processes were attenuated by co-treatment with the antioxidant N-acetyl cysteine (NAC, 1 mmol/L). Furthermore, TP treatment inhibited the translocation of Nrf2 from cytoplasm into the nucleus as well as the expression of downstream genes NAD(P)H quinone oxidoreductase1 (NQO1), catalase (CAT) and hemeoxygenase 1 (HO-1), thus abrogating Nrf2-mediated defense mechanisms against oxidative stress. Moreover, siRNA knockdown of Nrf2 significantly potentiated TP-induced apoptosis of TM4 cells. The above results from in vitro experiments were further validated in male mice after oral administration of TP (30, 60, and 120 mg·kg^-1·d^-1, for 14 d), as evidenced by the detected indexes, including dose-dependently decreased SDH activity, increased MDA concentration, altered testicle histomorphology, elevated caspase-3 activation, apoptosis induction, increased phosphorylation of JNK, and decreased gene expression of NQO1, CAT and HO-1 as well as nuclear protein expression of Nrf2 in testicular tissue. Our results demonstrate that TP activates apoptosis of Sertoli cells and injury of the testis via the ROS/JNK-mediated mitochondrial-dependent apoptosis pathway and down-regulates Nrf2 activation.

Critical Role of Hepatic Cyp450s in the Testis-Specific Toxicity of (5R)-5-Hydroxytriptolide in C57BL/6 Mice

Low solubility, tissue accumulation, and toxicity are chief obstacles to developing triptolide derivatives, so a better understanding of the pharmacokinetics and toxicity of triptolide derivatives will help with these limitations. To address this, we studied pharmacokinetics and toxicity of (5R)-5-hydroxytriptolide (LLDT-8), a novel triptolide derivative immunosuppressant in a conditional knockout (KO) mouse model with liver-specific deletion of CYP450 reductase. Compared to wild type (WT) mice, after LLDT-8 treatment, KO mice suffered severe testicular toxicity (decreased testicular weight, spermatocytes apoptosis) unlike WT mice. Moreover, KO mice had greater LLDT-8 exposure as confirmed with elevated AUC and Cmax, increased drug half-life, and greater tissue distribution. γ-H2AX, a marker of meiosis process, its localization and protein level in testis showed a distinct meiosis block induced by LLDT-8. RNA polymerase II (Pol II), an essential factor for RNA storage and synapsis in spermatogenesis, decreased in testes of KO mice after LLDT-8 treatment. Germ-cell line based assays confirmed that LLDT-8 selectively inhibited Pol II in spermatocyte-like cells. Importantly, the analysis of androgen receptor (AR) related genes showed that LLDT-8 did not change AR-related signaling in testes. Thus, hepatic CYP450s were responsible for in vivo metabolism and clearance of LLDT-8 and aggravated testicular injury may be due to increased LLDT-8 exposure in testis and subsequent Pol II reduction.

MYC Inhibition Depletes Cancer Stem-like Cells in Triple-Negative Breast Cancer

There is mounting evidence that cancer stem-like cells (CSC) are selectively enriched in residual tumors after anticancer therapies, which may account for tumor recurrence and metastasis by regenerating new tumors. Thus, there is a critical need to develop new therapeutic agents that can effectively eliminate drug-resistant CSCs and improve the efficacy of cancer therapy. Here, we report that Triptolide (C1572), a small-molecule natural product, selectively depletes CSCs in a dose-dependent fashion in human triple-negative breast cancer (TNBC) cell lines. Nanomolar concentrations of C1572 markedly reduced c-MYC (MYC) protein levels via a proteasome-dependent mechanism. Silencing MYC expression phenocopied the CSC depletion effects of C1572 and induced senescence in TNBC cells. Limited dilution assays revealed that ex vivo treatment of TNBC cells with C1572 reduced CSC levels by 28-fold. In mouse xenograft models of human TNBC, administration of C1572 suppressed tumor growth and depleted CSCs in a manner correlated with diminished MYC expression in residual tumor tissues. Together, these new findings provide a preclinical proof of concept defining C1572 as a promising therapeutic agent to eradicate CSCs for drug-resistant TNBC treatment. Cancer Res; 77(23); 6641-50. ©2017 AACR.

Triptolide inhibits the growth of osteosarcoma by regulating microRNA-181a via targeting PTEN gene in vivo and vitro

We aimed to study the anti-tumor effects of triptolide on osteosarcoma and the related molecular mechanisms. The cell viability, apoptosis portion, tumor size, tumor weight, and invasion of osteosarcoma cells were determined. The relative level of microRNA-181 in osteosarcoma tissues and the adjacent tissues was determined by quantitative real-time reverse transcription polymerase chain reaction. The target gene of microRNA-181a was determined and verified by luciferase report assay. At last, osteosarcoma cells were treated with triptolide and triptolide + microRNA-181a mimics to verify the relationship between triptolide and microRNA-181a. Triptolide inhibited the cell viability, promoted the apoptosis, decreased the tumor size and weight, and reduced the invasion of osteosarcoma cells. The level of microRNA-181a in osteosarcoma cells decreased significantly after treating with triptolide, and the relative level of microRNA-181a in osteosarcoma tissues was markedly higher than that in the adjacent tissues. PTEN was reported and verified the direct target gene of microRNA-181a. The overexpression of microRNA-181a decreased the inhibition of triptolide on osteosarcoma proliferation and promotion on osteosarcoma apoptosis. In conclusion, triptolide inhibited cell growth and invasion of osteosarcoma by regulating microRNA-181a via targeting PTEN gene in vivo and vitro.

Therapeutic Potential and Molecular Mechanisms of Emblica officinalis Gaertn in Countering Nephrotoxicity in Rats Induced by the Chemotherapeutic Agent Cisplatin

Emblica officinalis Gaertn. belonging to family Euphorbiaceae is commonly known as Indian gooseberry or "Amla" in India. It is used as a 'rejuvenating herb' in traditional system of Indian medicine. It has been shown to possess antioxidant, anti-inflammatory and anti-apoptotic effects. Thus, on the basis of its biological effects, the present study was undertaken to evaluate the protective effect of the dried fruit extract of the E. Officinalis (EO) in cisplatin-induced nephrotoxicity in rats and also to evaluate the mechanism of its nephroprotection. The study was done on male albino Wistar rats. They were divided into six groups (n = 6) viz. control, cisplatin-control, cisplatin and EO (150, 300, and 600 mg/kg; p.o. respectively in different groups) and EO only (600 mg/kg; p.o. only). EO was administered orally to the rats for a period of 10 days and on the 7th day, a single injection of cisplatin (8 mg/kg; i.p.) was administered to the cisplatin-control and EO treatment groups. The rats were sacrificed on the 10th day. Cisplatin-control rats had deranged renal function parameters and the kidney histology confirmed the presence of acute tubular necrosis. Furthermore, there were increased oxidative stress, apoptosis and inflammation along with higher expression of MAPK pathway proteins in the rat kidney from the cisplatin-control group. Contrary to this, EO (600 mg/kg) significantly normalized renal function, bolstered antioxidant status and ameliorated histological alterations. The inflammation and apoptosis were markedly lower in comparison to cisplatin-control rats. Furthermore, EO (600 mg/kg) inhibited MAPK phosphorylation which was instrumental in preserving renal function and morphology. In conclusion, the results of our study demonstrated that EO attenuated cisplatin-induced nephrotoxicity in rats through suppression of MAPK induced inflammation and apoptosis.

Molecular mechanisms underlying attenuation of cisplatin-induced acute kidney injury by epicatechin gallate

Cisplatin, a platinum compound, is used as a first-line agent against various forms of solid cancers. Nephrotoxicity is an important adverse effect of cisplatin therapy, which involves increased oxidative stress, inflammation, apoptosis, and activation of the mitogen-activated protein kinase (MAPK) pathway. It is well known that the bioactive compounds present in green tea are used to treat various disorders due to their biological activities. With this background, the present study was aimed to investigate the effect of epicatechin gallate (ECG), a green tea polyphenol, in cisplatin-induced nephrotoxicity in rats. To achieve this, ECG (1.25, 2.5, and 5 mg/kg; intraperitoneal (i.p.)) was administered to male albino Wistar rats for the period of 10 days. On the 7th day, a single i.p. injection of cisplatin (8 mg/kg) was injected into rats to produce kidney injury and the animals were then killed on the 10th day. Cisplatin toxicity was associated with enhanced oxidative stress, impaired renal function along with marked tubular necrosis in Histopathology. Furthermore, cisplatin activated the MAPK pathway, which contributed to inflammation and apoptosis in the kidney of treated rats. In contrast, ECG (5 mg/kg) pretreatment normalized cisplatin-induced oxidative stress, renal function, and histopathological changes. ECG also prevented the activation of the MAPK pathway, and attenuated inflammation and apoptosis in rats. These findings suggest that ECG prevented cisplatin-induced oxidative stress, inflammation, and apoptosis by downregulating the MAPK pathway and resulted in improved renal function.

CD4 T cell knockout does not protect against kidney injury and worsens cancer

Most previous studies of cisplatin-induced acute kidney injury (AKI) have been in models of acute, high-dose cisplatin administration that leads to mortality in non-tumor-bearing mice. The aim of the study was to determine whether CD4 T cell knockout protects against AKI and cancer in a clinically relevant model of low-dose cisplatin-induced AKI in mice with cancer. Kidney function, serum neutrophil gelatinase-associated lipocalin (NGAL), acute tubular necrosis (ATN), and tubular apoptosis score were the same in wild-type and CD4 -/- mice with AKI. The lack of protection against AKI in CD4 -/- mice was associated with an increase in extracellular signal-regulated kinase (ERK), p38, CXCL1, and TNF-α, mediators of AKI and fibrosis, in both cisplatin-treated CD4 -/- mice and wild-type mice. The lack of protection was independent of the presence of cancer or not. Tumor size was double, and cisplatin had an impaired therapeutic effect on the tumors in CD4 -/- vs. wild-type mice. Mice depleted of CD4 T cells using the GK1.5 antibody were not protected against AKI and had larger tumors and lesser response to cisplatin. In summary, in a clinically relevant model of cisplatin-induced AKI in mice with cancer, (1) CD4 -/- mice were not protected against AKI; (2) ERK, p38, CXCL1, and TNF-α, known mediators of AKI, and interstitial fibrosis were increased in CD4 -/- kidneys; and (3) CD4 -/- mice had faster tumor growth and an impaired therapeutic effect of cisplatin on the tumors. The data warns against the use of CD4 T cell inhibition to attenuate cisplatin-induced AKI in patients with cancer.

KEY MESSAGE

A clinically relevant low-dose cisplatin model of AKI in mice with cancer was used. CD4 -/- mice were not functionally or histologically protected against AKI. CD4 -/- mice had faster tumor growth. CD4 -/- mice had an impaired therapeutic effect of cisplatin on the tumors. Mice depleted of CD4 T cells were not protected against AKI and had larger tumors.