β-Hydroxybutyrate, a ketone body, reduces the cytotoxic effect of cisplatin via activation of HDAC5 in human renal cortical epithelial cells

Histone deacetylases and their inhibitors in kidney diseases

Histone deacetylases (HDACs) have emerged as key regulators in the pathogenesis of various kidney diseases. This review explores recent advancements in HDAC research, focusing on their role in kidney development and their critical involvement in the progression of chronic kidney disease (CKD), acute kidney injury (AKI), autosomal dominant polycystic kidney disease (ADPKD), and diabetic kidney disease (DKD). It also discusses the therapeutic potential of HDAC inhibitors in treating these conditions. Various HDAC inhibitors have shown promise by targeting specific HDAC isoforms and modulating a range of biological pathways. Their protective effects include modulation of apoptosis, autophagy, inflammation, and fibrosis, underscoring their broad therapeutic potential for kidney diseases. However, further research is essential to improve the selectivity of HDAC inhibitors, minimize toxicity, overcome drug resistance, and enhance their pharmacokinetic properties. This review offers insights to guide future research and prevention strategies for kidney disease management.

Histone deacetylases: potential therapeutic targets in cisplatin-induced acute kidney injury

Aim: Chemotherapy has been well shown to enhance life expectancy in patients with malignancy. However, conventional chemotherapy drugs, particularly cisplatin, are highly associated with nephrotoxicity, which limits therapeutic efficacy and impairs quality of life. Histone deacetylases (HDACs) are proteases that play significant roles in diseases by influencing protein post-translational modification and gene expression. Agents that inhibit HDAC enzymes have been developed and approved by the FDA as anticancer drugs. It is worth noting that in certain preclinical studies with tumour cell lines, the integration of HDAC modulators and cisplatin not only exerts synergistic or additive tumour-killing effects but also alleviates cisplatin nephrotoxicity. The aim of this review is to discuss the role of HDACs in cisplatin nephrotoxicity.

Methods: After searching in PubMed and Web of Science databases using 'Histone deacetylase', 'nephrotoxicity', 'cisplatin', and 'onconpehrology' as keywords, studies related was compiled and examined.

Results: HDAC inhibitors exert renal protective effects by inhibiting inflammation, apoptosis, oxidative stress, and promoting autophagy; whereas sirtuins play a renal protective role by regulating lipid metabolism, inhibiting inflammation and apoptosis, and protecting mitochondrial biosynthesis and mitochondrial dynamics. These potential interactions provide clues concerning targets for molecular treatment.

Conclusion: This review encapsulates the function and molecular mechanisms of HDACs in cisplatin nephrotoxicity, providing the current view by which HDACs induce different biological signaling in the regulation of chemotherapy-associated renal injury. More importantly, this review exhaustively elucidates that HDACs could be targeted to develop a new therapeutic strategy in treating cisplatin nephrotoxicity, which will extend the knowledge of the biological impact and clinical implications of HDACs.

Understanding Cisplatin Pharmacokinetics and Toxicodynamics to Predict and Prevent Kidney Injury

Cisplatin is a common platinum-based chemotherapeutic that induces acute kidney injury (AKI) in about 30% of patients. Pharmacokinetic/toxicodynamic (PKTD) models of cisplatin-induced AKI have been used to understand risk factors and evaluate potential mitigation strategies. While both traditional clinical biomarkers of kidney function [e.g., serum creatinine (SCr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and creatinine clearance (CrCl)] and newer subclinical biomarkers of kidney injury [e.g., urinary kidney injury molecule 1 (KIM-1), beta-2 microglobulin (B2M), neutrophil gelatinase-associated lipocalin (NGAL), calbindin, etc.] can be used to detect cisplatin-induced AKI, published PKTD models are limited to using only traditional clinical biomarkers. Previously identified risk factors for cisplatin nephrotoxicity have included dose, age, sex, race, body surface area, genetics, concomitant medications, and comorbid conditions. However, the relationships between concentrations and the pharmacokinetics (PK) of platinum and biomarkers of kidney injury have not been well elucidated. This review discusses the evaluation of cisplatin-induced nephrotoxicity in clinical studies, mouse models, and in vitro models, and examines the available human PK and toxicodynamic (TD) data. Improved understanding of the relationships between platinum PK and TD, in the presence of identified risk factors, will enable the prediction and prevention of cisplatin kidney injury. SIGNIFICANCE STATEMENT: As cisplatin treatment continues to cause AKI in a third of patients, it is critical to improve the understanding of the relationships between platinum PK and nephrotoxicity as assessed by traditional clinical and contemporary subclinical TD markers of kidney injury. Prediction and prevention of cisplatin-induced nephrotoxicity will be advanced by the evolving development of PKTD models that incorporate kidney injury biomarkers with enhanced sensitivity and include covariates that can impact risk of developing cisplatin-induced AKI.

Medium-chain triglycerides combined with DHA improve cognitive function by inhibiting neurocyte apoptosis of the brain in SAMP8 mice

Medium-chain triglycerides (MCTs) and docosahexaenoic acid (DHA, Cn-3, 22:6) are essential in improving cognitive function and protecting neurocytes. This study explored the effects of the combined intervention of MCTs and DHA on inhibiting neurocyte apoptosis of the brain and improving cognitive function in senescence-accelerated mouse-prone 8 (SAMP8). Four-month-old male SAMP8 mice were randomly divided into four treatment groups (12 mice/group): DHA, MCT, DHA + MCT, and control groups, which intervened for seven months. Twelve age-matched male senescence-accelerated mouse resistant 1 (SAMR1) was used as the natural aging group. TUNEL assay and HE staining were used to assess neurocyte apoptosis and damage in the brain of mice. Moreover, the cognitive function was analyzed using the Morris water maze (MWM) and open field (OF) tests. The results showed that the cognitive function of 11-month-old SAMP8 mice decreased with age, and further pathological examination revealed the damaged neurocyte structure, karyopyknosis, cell atrophy, and even apoptosis. MCTs combined with DHA supplementation could increase octanoic acid (C8:0), decanoic acid (C10:0), and DHA levels in the serum, inhibit neurocyte apoptosis, improve neurocyte damage, moreover delay age-related cognitive decline after seven-month treatment. Furthermore, combining MCTs and DHA was significantly more beneficial than MCTs or DHA alone. In conclusion, MCTs combined with DHA could delay cognitive decline by inhibiting neurocyte apoptosis of the brain in SAMP8 mice.

Developing poly(ethylene glycol)-b-poly(β-hydroxybutyrate)-based self-assembling prodrug for the management of cisplatin-induced acute kidney injury

Although β-hydroxybutyrate (BHB), one of the endogenous body ketones, possesses high bioactivities, it is rapidly consumed, metabolized, and eliminated from the body. In this study, we designed new self-assembling nanoparticles that sustainably released BHB to improve bioavailability and evaluated their efficacy in in vivo experiments using rodent animal models. Since poly(β-hydroxybutyrate) [poly(BHB)] is regarded as a polymeric prodrug that is hydrolyzed by endogenous enzymes and releases BHB in a sustained manner, our idea was to engineer hydrophobic poly(BHB) in one of the segments in the amphiphilic block copolymer, of which self-assembles in water to form nanoparticles of tens of nanometers in size (abbreviated as NanoBHB). Here, methoxy-poly(ethylene glycol) was employed as the hydrophilic segment of the block copolymer to stabilize the nanoparticles in aqueous environments, thus enabling NanoBHBs to be administrable both orally and through injection. Experimental results showed that NanoBHB has low toxicity and releases free BHB for an extended period in vitro and in vivo. Moreover, NanoBHB exhibits superior nephroprotective effects in cisplatin-induced acute kidney injury mouse models compared to low-molecular-weight (LMW) sodium BHB, suggesting the potential of NanoBHB as a sustainable release formulation to supply BHB for medicinal applications.

Ketone bodies in cell physiology and cancer

Ketogenic diets (KDs), fasting, or prolonged physical activity elevate serum ketone bodies (KBs) levels, providing an alternative fuel source for the brain and other organs. However, KBs play pleiotropic roles that go beyond their role in energy production. KBs can act as signaling metabolites, influence gene expression, proteins' posttranslational modifications (PTMs), inflammation, and oxidative stress. Here, we explore the impact of KBs on mammalian cell physiology, including aging and tissue regeneration. We also concentrate on KBs and cancer, given the extensive evidence that dietary approaches inducing ketosis, including fasting-mimicking diets (FMDs) and KDs, can prevent cancer and affect tumor progression.

Pre-treatment with β-hydroxybutyrate mitigates cisplatin-induced acute kidney injury

β-Hydroxybutyrate (β-HB), the primary circulating ketone body, plays a dual role as both a metabolic fuel and an endogenous signaling molecule, offering diverse systemic benefits. Recent studies have highlighted the renoprotective effects of exogenous β-HB therapy in various animal models of kidney disease. In this investigation, our goal was to assess whether pre-treatment with exogenous β-HB could alleviate kidney damage in a mouse model of cisplatin-induced acute kidney injury (AKI). Prior to cisplatin administration, intraperitoneal administration of β-HB was carried out, and the groups were classified into four: Sham, β-HB, cisplatin, and β-HB + cisplatin. The tubular damage score and serum creatinine levels were significantly lower in the β-HB + cisplatin group compared to the cisplatin group. Furthermore, the expression of phosphorylated NF-κB, inflammatory cytokines, and the quantity of F4/80-positive macrophages in the β-HB + cisplatin group were reduced compared to those in the cisplatin group. Additionally, oxidative stress markers for DNA, protein, and lipid in the β-HB + cisplatin group were markedly diminished compared to those in the cisplatin group. The number of TUNEL-positive and cleaved caspase 3-positive tubular cells in the β-HB + cisplatin group was lower than in the cisplatin group. Pre-treating with exogenous β-HB effectively mitigated kidney damage by suppressing inflammation, oxidative stress, and tubular apoptosis in cisplatin-induced AKI. Therefore, exogenous β-HB as a pre-treatment emerges as a promising and novel strategy for preventing cisplatin-induced AKI.

A novel therapeutic target for kidney diseases: Lessons learned from starvation response

The prevalence of chronic kidney disease (CKD) is increasing worldwide, making the disease an urgent clinical challenge. Caloric restriction has various anti-aging and organ-protective effects, and unraveling its molecular mechanisms may provide insight into the pathophysiology of CKD. In response to changes in nutritional status, intracellular nutrient signaling pathways show adaptive changes. When nutrients are abundant, signals such as mechanistic target of rapamycin complex 1 (mTORC1) are activated, driving cell proliferation and other processes. Conversely, others, such as sirtuins and AMP-activated protein kinase, are activated during energy scarcity, in an attempt to compensate. Autophagy, a cellular self-maintenance mechanism that is regulated by such signals, has also been reported to contribute to the progression of various kidney diseases. Furthermore, in recent years, ketone bodies, which have long been considered to be detrimental, have been reported to play a role as starvation signals, and thereby to have renoprotective effects, via the inhibition of mTORC1. Therefore, in this review, we discuss the role of mTORC1, which is one of the most extensively studied nutrient-related signals associated with kidney diseases, autophagy, and ketone body metabolism; and kidney energy metabolism as a novel therapeutic target for CKD.

Ketone Body Metabolism in Diabetic Kidney Disease

Ketone bodies have a negative image because of ketoacidosis, one of the acute and serious complications in diabetes. The negative image persists despite the fact that ketone bodies are physiologically produced in the liver and serve as an indispensable energy source in extrahepatic organs, particularly during long-term fasting. However, accumulating experimental evidence suggests that ketone bodies exert various health benefits. Particularly in the field of aging research, there is growing interest in the potential organoprotective effects of ketone bodies. In addition, ketone bodies have a potential role in preventing kidney diseases, including diabetic kidney disease (DKD), a diabetic complication caused by prolonged hyperglycemia that leads to a decline in kidney function. Ketone bodies may help alleviate the renal burden from hyperglycemia by being used as an alternative energy source in patients with diabetes. Furthermore, ketone body production may reduce inflammation and delay the progression of several kidney diseases in addition to DKD. Although there is still insufficient research on the use of ketone bodies as a treatment and their effects, their renoprotective effects are being gradually proven. This review outlines the ketone body-mediated renoprotective effects in DKD and other kidney diseases.

β-hydroxybutyrate ameliorates sepsis-induced acute kidney injury

BACKGROUND

Sepsis is a major cause of acute kidney injury (AKI). Recent studies have demonstrated that β-hydroxybutyrate (β-HB) alleviates renal ischemia-reperfusion injury and cisplatin-induced renal injury in murine models. This study aimed to investigate whether β-HB ameliorates sepsis-induced AKI (SIAKI) in a lipopolysaccharide (LPS)-induced mouse sepsis model.

METHODS AND RESULTS

SIAKI was induced by intraperitoneally injecting LPS to C57BL/6 male mice. β-HB was administrated intraperitoneally before LPS injection. The mice were divided into sham, β-HB, LPS, and β-HB + LPS groups. The histological damage score and serum creatinine level were significantly increased in the LPS group mice, but attenuated in the β-HB + LPS group mice. The expression of phosphorylated nuclear factor-κB tumor necrosis factor-α/interleukin-6 and the number of F4/80-positive macrophages in the β-HB + LPS group mice were lower than those in the LPS group mice. The number of TdT-mediated dUTP nick-end labeling (TUNEL)-positive tubular cells, cleaved caspase-3 expression, and Bax/Bcl-2 ratio in the β-HB + LPS group mice were lower than those in the LPS group mice.

CONCLUSION

β-HB pre-treatment ameliorates SIAKI by reducing tubular apoptosis and inflammatory responses. Thus, β-HB pre-treatment could be a potential prophylactic strategy against SIAKI.

The Role of Ketone Bodies in Various Animal Models of Kidney Disease

The kidney is a vital organ that carries out significant metabolic functions in our body. Due to the complexity of its role, the kidney is also susceptible to many disease conditions, such as acute kidney injury (AKI) and chronic kidney disease (CKD). Despite the prevalence and our increased understanding of the pathophysiology of both AKI and CKD as well as the transition of AKI to CKD, no well-established therapeutics have been applied clinically to these conditions, rendering an urgent need for a novel potential therapeutic target to be developed. In this article, we reviewed the function of ketone bodies in some common kidney conditions, such as drug-induced nephrotoxicity, ischemia and reperfusion injury, fibrosis development, diabetic kidney disease, kidney aging, hypertension, and CKD progression. All the selected studies reviewed were performed in animal models by primarily utilizing rodents, which also provide invaluable sources for future clinical applications. Ketone bodies have shown significant renal protective properties via attenuation of oxidative stress, increased expression of anti-inflammatory proteins, gene regulation, and a reduction of apoptosis of renal cells. A physiological level of ketone bodies could be achieved by fasting, a ketogenic diet, and an exogenous ketone supplement. Finally, the limitations of the long-term ketogenic diet were also discussed.

Cisplatin nephrotoxicity: new insights and therapeutic implications

Cisplatin is an effective chemotherapeutic agent for various solid tumours, but its use is limited by adverse effects in normal tissues. In particular, cisplatin is nephrotoxic and can cause acute kidney injury and chronic kidney disease. Preclinical studies have provided insights into the cellular and molecular mechanisms of cisplatin nephrotoxicity, which involve intracellular stresses including DNA damage, mitochondrial pathology, oxidative stress and endoplasmic reticulum stress. Stress responses, including autophagy, cell-cycle arrest, senescence, apoptosis, programmed necrosis and inflammation have key roles in the pathogenesis of cisplatin nephrotoxicity. In addition, emerging evidence suggests a contribution of epigenetic changes to cisplatin-induced acute kidney injury and chronic kidney disease. Further research is needed to determine how these pathways are integrated and to identify the cell type-specific roles of critical molecules involved in regulated necrosis, inflammation and epigenetic modifications in cisplatin nephrotoxicity. A number of potential therapeutic targets for cisplatin nephrotoxicity have been identified. However, the effects of renoprotective strategies on the efficacy of cisplatin chemotherapy needs to be thoroughly evaluated. Further research using tumour-bearing animals, multi-omics and genome-wide association studies will enable a comprehensive understanding of the complex cellular and molecular mechanisms of cisplatin nephrotoxicity and potentially lead to the identification of specific targets to protect the kidney without compromising the chemotherapeutic efficacy of cisplatin.

Ketogenic diet alleviates renal fibrosis in mice by enhancing fatty acid oxidation through the free fatty acid receptor 3 pathway

Introduction

The ketogenic diet (KD), as a dietary intervention, has gained importance in the treatment of solid organ structural remodeling, but its role in renal fibrosis has not been explored.

Methods

Male C57BL/6 mice were fed a normal diet or a KD for 6 weeks prior to unilateral ureteral obstruction (UUO), a well-established in vivo model of renal fibrosis in rodents. Seven days after UUO, serum and kidney samples were collected. Serum β-hydroxybutyrate (β-OHB) concentrations and renal fibrosis were assessed. NRK52E cells were treated with TGFβ1, a fibrosis-inducing cytokine, and with or without β-OHB, a ketone body metabolized by KD, to investigate the mechanism underlying renal fibrosis.

Results

KD significantly enhanced serum β-OHB levels in mice. Histological analysis revealed that KD alleviated structural destruction and fibrosis in obstructed kidneys and reduced the expression of the fibrosis protein markers α-SMA, Col1a1, and Col3a1. Expression of the rate-limiting enzymes involved in fatty acid oxidation (FAO), Cpt1a and Acox1, significantly decreased after UUO and were upregulated by KD. However, the protective effect of KD was abolished by etomoxir (a Cpt1a inhibitor). Besides, our study observed that KD significantly suppressed UUO-induced macrophage infiltration and the expression of IL-6 in the obstructive kidneys. In NRK52E cells, fibrosis-related signaling was increased by TGFβ1 and reduced by β-OHB. β-OHB treatment restored the impaired expression of Cpt1a. The effect of β-OHB was blocked by siRNA targeting free fatty acid receptor 3 (FFAR3), suggesting that β-OHB might function through the FFAR3-dependent pathway.

Discussion

Our results highlight that KD attenuates UUO-induced renal fibrosis by enhancing FAO via the FFAR3-dependent pathway, which provides a promising dietary therapy for renal fibrosis.

Critical Reanalysis of the Mechanisms Underlying the Cardiorenal Benefits of SGLT2 Inhibitors and Reaffirmation of the Nutrient Deprivation Signaling/Autophagy Hypothesis

SGLT2 (sodium-glucose cotransporter 2) inhibitors produce a distinctive pattern of benefits on the evolution and progression of cardiomyopathy and nephropathy, which is characterized by a reduction in oxidative and endoplasmic reticulum stress, restoration of mitochondrial health and enhanced mitochondrial biogenesis, a decrease in proinflammatory and profibrotic pathways, and preservation of cellular and organ integrity and viability. A substantial body of evidence indicates that this characteristic pattern of responses can be explained by the action of SGLT2 inhibitors to promote cellular housekeeping by enhancing autophagic flux, an effect that may be related to the action of these drugs to produce simultaneous upregulation of nutrient deprivation signaling and downregulation of nutrient surplus signaling, as manifested by an increase in the expression and activity of AMPK (adenosine monophosphate-activated protein kinase), SIRT1 (sirtuin 1), SIRT3 (sirtuin 3), SIRT6 (sirtuin 6), and PGC1-α (peroxisome proliferator-activated receptor γ coactivator 1-α) and decreased activation of mTOR (mammalian target of rapamycin). The distinctive pattern of cardioprotective and renoprotective effects of SGLT2 inhibitors is abolished by specific inhibition or knockdown of autophagy, AMPK, and sirtuins. In the clinical setting, the pattern of differentially increased proteins identified in proteomics analyses of blood collected in randomized trials is consistent with these findings. Clinical studies have also shown that SGLT2 inhibitors promote gluconeogenesis, ketogenesis, and erythrocytosis and reduce uricemia, the hallmarks of nutrient deprivation signaling and the principal statistical mediators of the ability of SGLT2 inhibitors to reduce the risk of heart failure and serious renal events. The action of SGLT2 inhibitors to augment autophagic flux is seen in isolated cells and tissues that do not express SGLT2 and are not exposed to changes in environmental glucose or ketones and may be related to an ability of these drugs to bind directly to sirtuins or mTOR. Changes in renal or cardiovascular physiology or metabolism cannot explain the benefits of SGLT2 inhibitors either experimentally or clinically. The direct molecular effects of SGLT2 inhibitors in isolated cells are consistent with the concept that SGLT2 acts as a nutrient surplus sensor, and thus, its inhibition causes enhanced nutrient deprivation signaling and its attendant cytoprotective effects, which can be abolished by specific inhibition or knockdown of AMPK, sirtuins, and autophagic flux.

β-Hydroxybutyrate against Cisplatin-Induced acute kidney injury via inhibiting NLRP3 inflammasome and oxidative stress

Cisplatin, as a commonly used anticancer drug, can easily lead to acute kidney injury (AKI), and has received more and more attention in clinical practice. β-hydroxybutyric acid (BHB) is a metabolite in the body and acts as an inhibitor of oxidative stress and NLRP3 inflammasome, reducing inflammatory responses and apoptosis. However, the role of BHB in cisplatin-induced AKI is currently not fully elucidated. In this study, C57BL/6 male mice were randomly divided into normal control group, cisplatin-induced AKI group and AKI with BHB treatment group. Compared to the control, cisplatin-treated mice exhibited high level of serum creatinine, blood urea nitrogen and severe tubular injury, which accompanied with significantly increased expression level of NLRP3, IL-1β, IL-18, BAX, cleaved-caspase 3, as well as aggravated oxidative stress and renal tubular cell apoptosis. However, these changes were significantly improved in that of BHB treatment. In vitro, our study showed that the expression of cleaved-caspase3, IL-1β and IL-18 were significantly increased in human proximal tubular epithelial cell line (HK-2) treated with cisplatin compared with the control group, while decreased in cells treated with BHB. Furthermore, a significantly increased expression of cGAS and STING in HK-2 cells treated with cisplatin were found, whereas notably decreased in cells treated with BHB. This data indicates that BHB protects against cisplatin-induced AKI and renal tubular damage mediated by NLRP3 inflammasome and cGAS-STING pathway.

Cisplatin-Induced Kidney Toxicity: Potential Roles of Major NAD+-Dependent Enzymes and Plant-Derived Natural Products

Cisplatin is an FDA approved anti-cancer drug that is widely used for the treatment of a variety of solid tumors. However, the severe adverse effects of cisplatin, particularly kidney toxicity, restrict its clinical and medication applications. The major mechanisms of cisplatin-induced renal toxicity involve oxidative stress, inflammation, and renal fibrosis, which are covered in this short review. In particular, we review the underlying mechanisms of cisplatin kidney injury in the context of NAD+-dependent redox enzymes including mitochondrial complex I, NAD kinase, CD38, sirtuins, poly-ADP ribosylase polymerase, and nicotinamide nucleotide transhydrogenase (NNT) and their potential contributing roles in the amelioration of cisplatin-induced kidney injury conferred by natural products derived from plants. We also cover general procedures used to create animal models of cisplatin-induced kidney injury involving mice and rats. We highlight the fact that more studies will be needed to dissect the role of each NAD+-dependent redox enzyme and its involvement in modulating cisplatin-induced kidney injury, in conjunction with intensive research in NAD+ redox biology and the protective effects of natural products against cisplatin-induced kidney injury.

Imazalil and its metabolite imazalil-M caused developmental toxicity in zebrafish (Danio rerio) embryos via cell apoptosis mediated by metabolic disorders

Imazalil (IMZ) is a highly effective fungicide employed in crop production. It has been consistently detected in aquatic environments. The main environmental metabolite of IMZ is imazalil-M (IMZ-M). Limited studies have focused on the toxicity of IMZ and IMZ-M in aquatic organisms. This study systematically evaluated the developmental toxicity of IMZ and IMZ-M on zebrafish (Danio rerio) embryos and explored the potential mechanisms involved. The results showed that IMZ and IMZ-M caused developmental toxicity, characterized by decreased heart rate, hatching inhibition, and pericardial cyst in zebrafish embryos. Subsequently, acridine orange (AO) staining revealed cell apoptosis in the area around the heart regions of zebrafish larvae. Besides, the expression levels of apoptosis-related genes also varied significantly. Furthermore, ¹H NMR-based metabolomics analysis showed that IMZ and IMZ-M exposure could induce metabolic profiles disorder in zebrafish larvae. Importantly, zebrafish exposure to IMZ and IMZ-M significantly affected the metabolism of branched - chain amino acids, energy, and ketone bodies, which are related to cell apoptosis. Overall, the toxicity of IMZ and IMZ-M in zebrafish embryos and larvae was characterized, suggesting a theoretical basis for the potential environmental risks of IMZ and its metabolite IMZ-M on non-target organisms.

Discovery of metabolomic biomarkers for discriminating platinum-sensitive and platinum-resistant ovarian cancer by using GC-MS

This study aims to determine ovarian cancer (OC) patients with platinum resistance for alternative treatment protocols by using metabolomic methodologies. Urine and serum samples of platinum-resistant and platinum-sensitive OC were analyzed using GC-MS. After data processing of GC-MS raw data, multivariate analyses were performed to interpret complex data for biologically meaningful information and to identify the biomarkers that cause differences between two groups. The biomarkers were verified after univariate, multivariate, and ROC analysis. Finally, metabolomic pathways related to group separations were specified. The results of biomarker analysis showed that 3,4-dihydroxyphenylacetic acid, 4-hydroxybutyric acid, L-threonine, D- mannose, and sorbitol metabolites were potential biomarkers in urine samples. In serum samples, L-arginine, linoleic acid, L-glutamine, and hypoxanthine were identified as important biomarkers. R2Y, Q2, AUC, sensitivity and specificity values of platinum-resistant and sensitive OC patients' urine and serum samples were 0.85, 0.545, 0.844, 91.30%, 81.08 and 0.570, 0.206, 0.743, 77.78%, 74.28%, respectively. In metabolic pathway analysis of urine samples, tyrosine metabolism and fructose and mannose metabolism were found to be statistically significant (p < 0.05) for the discrimination of the two groups. While 3,4-dihydroxyphenylacetic acid, L-tyrosine, and fumaric acid metabolites were effective in tyrosine metabolism. D-sorbitol and D-mannose metabolites were significantly important in fructose and mannose metabolism. However, seven metabolomic pathways were significant (p < 0.05) in serum samples. In terms of p-value, L-glutamine in the nitrogen metabolic pathway from the first three pathways; L-glutamine and pyroglutamic acid metabolites in D-glutamine and D-glutamate metabolism. In the arginine and proline metabolic pathway, L-arginine, L-proline, and L-ornithine metabolites differed significantly between the two groups.

TLR4 Knockout Attenuates BDL-induced Liver Cholestatic Injury through Amino Acid and Choline Metabolic Pathways

The exact mechanism by which knockout of Toll-like receptor 4 (TLR4) attenuates the liver injury remains unclear. The present study aimed to examine the role of TLR4 in the pathogenesis of bile duct ligation (BDL)-induced liver cholestatic injury and the underlying mechanism. Wild type (WT) mice and TLR4 knockout (TLR4-KO) mice were used for the establishment of the BDL model. Metabolomics were applied to analyze the changes of small molecular metabolites in the serum and liver of the two groups. The serum biochemical indexes and the HE staining results of liver tissue showed that liver damage was significantly reduced in TLR4-KO mice after BDL when compared with that in WT mice. The metabolite analysis results showed that TLR4 KO could maintain the metabolisms of amino acids- and choline-related metabolites. After BDL, the amino acids- and choline-related metabolites, especially choline and 3-hydroxybutyrate, were significantly increased in WT mice (both in serum and liver), but these metabolites in the liver of TLR4-KO mice after BLD were not significant different from those before BLD. In conclusion, TLR4 KO could attenuate BDL-induced liver cholestatic injury through regulating amino acid and choline metabolic pathways.

Epigenetic Mechanisms Involved in Cisplatin-Induced Nephrotoxicity: An Update

Cisplatin is an antineoplastic drug used for the treatment of many solid tumors. Among its various side effects, nephrotoxicity is the most detrimental. In recent years, epigenetic regulation has emerged as a modulatory mechanism of cisplatin-induced nephrotoxicity, involving non-coding RNAs, DNA methylation and histone modifications. These epigenetic marks alter different signaling pathways leading to damage and cell death. In this review, we describe how different epigenetic modifications alter different pathways leading to cell death by apoptosis, autophagy, necroptosis, among others. The study of epigenetic regulation is still under development, and much research remains to fully determine the epigenetic mechanisms underlying cell death, which will allow leading new strategies for the diagnosis and therapy of this disease.

1H NMR and UHPLC/Q-Orbitrap-MS-Based Metabolomics Combined with 16S rRNA Gut Microbiota Analysis Revealed the Potential Regulation Mechanism of Nuciferine in Hyperuricemia Rats

Hyperuricemia seriously jeopardizes human health by increasing the risk of several diseases, such as gout and stroke. Nuciferine is able to alleviate hyperuricemia significantly. However, the underlying metabolic regulation mechanism remains unknown. To understand the metabolic effects of nuciferine on hyperuricemia by establishing a rat model of rapid hyperuricemia, ¹H NMR and liquid chromatography-mass spectrometry were used to conduct nontargeted metabolomics studies. A total of 21 metabolites were authenticated in plasma and urine to be closely related with hyperuricemia, which were mainly correlated to the six metabolic pathways. Moreover, 16S rRNA analysis indicated that diversified intestinal microorganisms are closely related to changes in differential metabolites, especially bacteria from Firmicutes and Bacteroidetes. We propose that indoxyl sulfate and N-acetylglutamate in urine may be the potential biomarkers besides uric acid for early diagnosis and prevention of hyperuricemia. Gut microbiological analysis found that changes in the gut microbiota are closely related to these metabolites.

β-Hydroxybutyrate enhances the cytotoxic effect of cisplatin via the inhibition of HDAC/survivin axis in human hepatocellular carcinoma cells

Ketone bodies, including acetoacetate and β-hydroxybutyrate (βOHB), are produced from acetyl coenzyme A in the liver and then secreted into the blood. These molecules are a source of energy for peripheral tissues during exercise or fasting. βOHB has been reported to inhibit histone deacetylases (HDACs) 1, 3, and 4 in human embryonic kidney 293 cells. Thus, βOHB may regulate epigenetics by modulating HDACs. There have been several reports that the administration of βOHB or induction of a physiological state of ketosis has an antitumor effect; however, the mechanism remains unclear. The aim of this study was to investigate whether βOHB enhances cisplatin-induced apoptosis in hepatocellular carcinoma (HCC) cells by modulating activity and/or expression of HDACs. We found that βOHB significantly enhanced cisplatin-induced apoptosis and cleavage of caspase-3 and -8 in HCC cells. Further, βOHB significantly decreased the expression of HDCA 3/5/6 and survivin in liver hepatocellular (HepG2) cells. In HDAC3/6 gene silencing, survivin expression was significantly decreased, and cisplatin-induced cleavage of caspase-3 was significantly enhanced compared with control in HepG2 cells. In conclusion, βOHB enhanced cisplatin-induced apoptosis via HDAC3/6 inhibition/survivin axis in HepG2 cells, which suggests that βOHB could be a new adjuvant agent for cisplatin chemotherapy.