Methotrexate Promotes Platelet Apoptosis via JNK-Mediated Mitochondrial Damage: Alleviation by N-Acetylcysteine and N-Acetylcysteine Amide

Oxidative Stress-Induced Platelet Apoptosis/Activation: Alleviation by Purified Curcumin via ASK1-JNK/p-38 Pathway

Platelets are known for their indispensable role in hemostasis and thrombosis. However, alteration in platelet function due to oxidative stress is known to mediate various health complications, including cardiovascular diseases and other health complications. To date, several synthetic molecules have displayed antiplatelet activity; however, their uses are associated with bleeding and other adverse effects. The commercially available curcumin is generally a mixture of three curcuminoids: curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Although crude curcumin is known to inhibit platelet aggregation, the effect of purified curcumin on platelet apoptosis, activation, and aggregation remains unclear. Therefore, in this study, curcumin was purified from a crude curcumin mixture and the effects of this preparation on the oxidative stress-induced platelet apoptosis and activation was evaluated. 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH) compound was used as an inducer of oxidative stress. Purified curcumin restored AAPH-induced platelet apoptotic markers like reactive oxygen species, intracellular calcium level, mitochondrial membrane potential, cardiolipin peroxidation, cytochrome c release from mitochondria to the cytosol, and phosphatidyl serine externalization. Further, it inhibited the agonist-induced platelet activation and aggregation, demonstrating its antiplatelet activity. Western blot analysis confirms protective effect of the purified curcumin against oxidative stress-induced platelet apoptosis and activation via downregulation of MAPKs protein activation, including ASK1, JNK, and p-38. Together, these results suggest that the purified curcumin could be a potential therapeutic bioactive molecule to treat the oxidative stress-induced platelet activation, apoptosis, and associated complications.

L-methionine protects against nephrotoxicity induced by methotrexate through modulation of redox status and inflammation

Objective: Methotrexate (MTX) is a drug used in the treatment of cancer and autoimmune disorders; however, its clinical use is limited because of serious side effects including renal toxicity. This study aimed to investigate the protective effect of Lmethionine (L-Met) on MTX toxicity in the kidneys of rats.Methods: Thirty male rats were divided equally into five groups: control (saline), Met400 (400 mg/kg L-Met), MTX (20 mg/kg MTX), MTX-Met300 (300 mg/kg L-Met and 20 mg/kg MTX), and MTX-Met400 (400 mg/kg L-Met and 20 mg/kg MTX). Rats were euthanized one day after the last dose administration (day 16) and serum and renal tissue samples were collected. Renal function and injury indices, oxidative stress/antioxidant indices and proinflammatory cytokines were evaluated.Results: The results showed that L-Met could effectively counteract the nephrotoxic effects of MTX, in a dose-related manner, by improving most of the tested parameters. Furthermore, the higher dose of L-Met was able to restore several parameters to normal levels. In addition, investigation of MTX-induced hematological changes revealed a corrective potential of L-Met.Conclusion: L-Met can be an effective adjuvant therapy to modulate renal toxicity associated with MTX because of its antioxidant and antiinflammatory effects.

Alantolactone induces platelet apoptosis by activating the Akt pathway

Alantolactone (ALT), a sesquiterpene lactone compound isolated from Inula helenium L., has recently attracted much attention for its anti-tumor properties. ALT reportedly functions by regulating the Akt pathway, which has been shown to be involved in programmed platelet death (apoptosis) and platelet activation. However, the precise effect of ALT on platelets remains unclear. In this study, washed platelets were treated with ALT in vitro, and apoptotic events and platelet activation were detected. In vivo, platelet transfusion experiments were employed to detect the effect of ALT on platelet clearance. Platelet counts were examined after intravenous injection of ALT. We found that ALT treatment induced Akt activation and Akt-mediated apoptosis in platelets. ALT-activated Akt elicited platelet apoptosis by activating phosphodiesterase (PDE3A) and PDE3A-mediated protein kinase A (PKA) inhibition. Pharmacological inhibition of the PI3K/Akt/PDE3A signaling pathway or PKA activation was found to protect platelets from apoptosis induced by ALT. Moreover, ALT-induced apoptotic platelets were removed faster in vivo, and ALT injection resulted in the platelet count decline. Either PI3K/Akt/PDE3A inhibitors or a PKA activator could protect platelets from clearance, ultimately ameliorating the ALT-induced decline in platelet count in the animal model. These results reveal the effects of ALT on platelets and their related mechanisms, suggesting potential therapeutic targets for the prevention and alleviation of possible side effects resulting from ALT treatments.

Hepatotoxicity from high-dose methotrexate in primary central nervous system lymphoma

Background

High-dose methotrexate (HDMTX) is a mainstay of primary central nervous system lymphoma (PCNSL) treatment. Transient hepatotoxicity from HDMTX has been characterized in pediatric patients but not in adults. We sought to characterize hepatotoxicity in adult PCNSL patients undergoing HDMTX treatment.

Methods

Retrospective study of 65 PCNSL patients treated at the University of Virginia from 02/01/2002 to 04/01/2020 was performed. Hepatotoxicity was defined using National Cancer Institute Common Toxicity Criteria (CTC) for adverse events, fifth version. High-grade hepatotoxicity was defined as a bilirubin or aminotransferase CTC grade of 3 or 4. Relationships between clinical factors and hepatotoxicity were assessed with logistic regression.

Results

Most patients (90.8%) had a rise of at least one aminotransferase CTC grade during HDMTX treatment. 46.2% had high-grade hepatotoxicity based on aminotransferase CTC grade. No patients developed high-grade bilirubin CTC grades during chemotherapy. Liver enzyme test values decreased to low CTC grade or normal in 93.8% of patients after the conclusion of HDMTX treatment without treatment regimen changes. Prior ALT elevation (P = .0120) was a statistically significant predictor of high-grade hepatotoxicity during treatment. Prior history of hypertension was associated with increased risk of toxic serum methotrexate levels during any cycle (P = .0036).

Conclusions

Hepatotoxicity develops in the majority of HDMTX-treated PCNSL patients. Transaminase values decreased to low or normal CTC grades in almost all patients after treatment, without modification of MTX dosage. Prior ALT elevation may predict patients' increased hepatotoxicity risk, and hypertension history may be a risk factor for delayed MTX excretion.

Discovery of Pyrimidine- and Coumarin-Linked Hybrid Molecules as Inducers of JNK Phosphorylation through ROS Generation in Breast Cancer Cells

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer exhibits early relapses, poor prognoses, and high recurrence rates. Herein, a JNK-targeting compound has been developed that may be of utility in HER2-positive mammary carcinoma. The design of a pyrimidine-and coumarin-linked structure targeting JNK was explored and the lead structure PC-12 [4-(3-((2-((4-chlorobenzyl)thio) pyrimidin-4-yl)oxy)propoxy)-6-fluoro-2H-chromen-2-one (5d)] was observed to selectively inhibit the proliferation of HER2-positive BC cells. The compound PC-12 exerted DNA damage and induced apoptosis in HER-2 positive BC cells more significantly compared to HER-2 negative BC cells. PC-12 induced PARP cleavage and down-regulated the expression of IAP-1, BCL-2, SURVIVIN, and CYCLIN D1 in BC cells. In silico and theoretical calculations showed that PC-12 could interact with JNK, and in vitro studies demonstrated that it enhanced JNK phosphorylation through ROS generation. Overall, these findings will assist the discovery of new compounds targeting JNK for use in HER2-positive BC cells.

Apoptosis versus necrosis in tubal ectopic pregnancies following Methotrexate

Methotrexate administration for the treatment of tubal ectopic pregnancies has been shown to cause tubal mass enlargement. Our hypothesis was that, by administrating Methotrexate, a local necrotic reaction occurs, leading to hematoma formation and eventually fallopian tube rupture. Salpingectomy specimens were collected, analysed and divided into three equal groups: patients who received Methotrexate but who ultimately failed medical treatment, patients who had a viable ectopic pregnancy and patients with a self-resolving ectopic pregnancy that were operated due to other medical indications. The specimens were dyed using the Cleaved Caspase-3 (Asp175) Rabbit mA. Specimens were divided into three equal groups and analysed. The patients in self-resolving ectopic pregnancy group were older and had more pregnancies. Rates of apoptosis were found to be less than 1% per slide. Necrosis was not evident in any of the pathological specimens. It seems Methotrexate administration does not lead to a significant tubal necrotic reaction. Further studies are required.

Glutathione levels are associated with methotrexate resistance in acute lymphoblastic leukemia cell lines

Introduction

Methotrexate (MTX), a folic acid antagonist and nucleotide synthesis inhibitor, is a cornerstone drug used against acute lymphoblastic leukemia (ALL), but its mechanism of action and resistance continues to be unraveled even after decades of clinical use.

Methods

To better understand the mechanisms of this drug, we accessed the intracellular metabolic content of 13 ALL cell lines treated with MTX by 1H-NMR, and correlated metabolome data with cell proliferation and gene expression. Further, we validated these findings by inhibiting the cellular antioxidant system of the cells in vitro and in vivo in the presence of MTX.

Results

MTX altered the concentration of 31 out of 70 metabolites analyzed, suggesting inhibition of the glycine cleavage system, the pentose phosphate pathway, purine and pyrimidine synthesis, phospholipid metabolism, and bile acid uptake. We found that glutathione (GSH) levels were associated with MTX resistance in both treated and untreated cells, suggesting a new constitutive metabolic-based mechanism of resistance to the drug. Gene expression analyses showed that eight genes involved in GSH metabolism were correlated to GSH concentrations, 2 of which (gamma-glutamyltransferase 1 [GGT1] and thioredoxin reductase 3 [TXNRD3]) were also correlated to MTX resistance. Gene set enrichment analysis (GSEA) confirmed the association between GSH metabolism and MTX resistance. Pharmacological inhibition or stimulation of the main antioxidant systems of the cell, GSH and thioredoxin, confirmed their importance in MTX resistance. Arsenic trioxide (ATO), a thioredoxin inhibitor used against acute promyelocytic leukemia, potentiated MTX cytotoxicity in vitro in some of the ALL cell lines tested. Likewise, the ATO+MTX combination decreased tumor burden and extended the survival of NOD scid gamma (NSG) mice transplanted with patient-derived ALL xenograft, but only in one of four ALLs tested.

Conclusion

Altogether, our results show that the cellular antioxidant defense systems contribute to leukemia resistance to MTX, and targeting these pathways, especially the thioredoxin antioxidant system, may be a promising strategy for resensitizing ALL to MTX.

Overview of Methotrexate Toxicity: A Comprehensive Literature Review

Methotrexate (MTX) is significantly more effective than and has a considerable advantage over placebo in patients with severe and persistent rheumatoid arthritis (RA). The drug is used to treat a variety of malignant disorders (leukemia and cancer of the lung, breast, and uterus) and ectopic pregnancy. As its side effects are outweighed by its effectiveness, MTX is a first-line antirheumatic drug in many countries. MTX is found in extracellular compartments, such as the synovium, as well as other organs, such as the kidney and liver. To improve treatment, increase adherence, and decrease mortality in MTX therapy, it is essential to reduce its toxicity and understand its side effects. Therefore, this comprehensive review was conducted to assist physicians and researchers in better understanding the toxicity of MTX and how to deal with this toxicity. MTX is eliminated via the kidneys, which are capable of excretion and reabsorption within the renal tubules. Although higher doses of MTX (known as high-dose MTX (HD-MTX), defined as doses of 500 mg/m² or greater) are often more beneficial, they can produce toxicity and side effects such as bone marrow suppression, pulmonary toxicity, nephrotoxicity, hematologic toxicity, and an increased risk of infections. Treatment of severe MTX toxicity has three main goals: clearance of MTX from the bloodstream, folinic acid therapy, and organ treatment. Leucovorin is highly beneficial in preventing myelosuppression, gastric toxicity, and neurotoxic effects after HD-MTX therapy. The preferred antidote for MTX poisoning is folinic acid. Glucarpidase has been licensed for the treatment of high plasma MTX levels of >1 μmol/L in patients with compromised renal function who have delayed MTX elimination. In patients with renal deficiency, a lower initial dose is considered with an estimated glomerular filtration rate (eGFR) between 30 and 59 mL/minute. These patients need to be monitored, and a more gradual dosage increase and a lower weekly maximum should be considered regarding their general health situation. MTX is contraindicated in patients with RA if the eGFR is <30 mL/minute.

Mitochondrial Dysfunction in Rheumatoid Arthritis

Rheumatoid arthritis, a chronic autoimmune disease with complex etiology, is characterized by excessive proliferation of synovial cells, massive production of inflammatory cells and cartilage destruction. Studies have shown that mitochondrial dysfunction plays an important role in promoting the occurrence of RA. Mitochondria with normal structure and function are essential for the normal survival of chondrocytes and synovial cells. Once mitochondrial function is destroyed, it will affect the survival, activation and differentiation of immune cells and non-immune cells involved in the pathogenesis of RA, thus leading to the occurrence of RA. However, the mechanism of mitochondrial dysfunction in RA remains unclear. This article reviews the method of mitochondrial dysfunction leading to RA, the effects of mitochondrial dysfunction on immune cells, the etiology of mitochondrial dysfunction in RA, and the pathology of mitochondrial dysfunction in RA. We also outline some drugs that can exert therapeutic effects on RA which are associated with modulating mitochondrial activity. The understanding and summary of mitochondrial dysfunction in RA may provide new research directions for pathological intervention and prevention of RA.

Emerging therapeutic opportunities of novel thiol-amides, NAC-amide (AD4/NACA) and thioredoxin mimetics (TXM-Peptides) for neurodegenerative-related disorders

Understanding neurodegenerative diseases have challenged scientists for decades. It has become apparent that a decrease in life span is often correlated with the development of neurodegenerative disorders. Oxidative stress and the subsequent inflammatory damages appear to contribute to the different molecular and biochemical mechanisms associated with neurodegeneration. In this review, I examine the protective properties of novel amino acid based compounds, comprising the AD series (AD1-AD7) in particular N-acetylcysteine amide, AD4, also called NACA, and the series of thioredoxin mimetic (TXM) peptides, TXM-CB3-TXM-CB16. Designed to cross the blood-brain-barrier (BBB) and permeate the cell membrane, these antioxidant/anti-inflammatory compounds may enable effective treatment of neurodegenerative related disorders. The review addresses the molecular mechanism of cellular protection exhibited by these new reagents, focusing on the reversal of oxidative stress, mitochondrial stress, inflammatory damages, and prevention of premature cell death. In addition, it will cover the outlook of the clinical prospects of AD4/NACA and the thioredoxin-mimetic peptides, which are currently in development.

Mesenchymal Stem Cell-Based Therapy for Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) have great potential to differentiate into various types of cells, including but not limited to, adipocytes, chondrocytes and osteoblasts. In addition to their progenitor characteristics, MSCs hold unique immunomodulatory properties that provide new opportunities in the treatment of autoimmune diseases, and can serve as a promising tool in stem cell-based therapy. Rheumatoid arthritis (RA) is a chronic systemic autoimmune disorder that deteriorates quality and function of the synovium membrane, resulting in chronic inflammation, pain and progressive cartilage and bone destruction. The mechanism of RA pathogenesis is associated with dysregulation of innate and adaptive immunity. Current conventional treatments by steroid drugs, antirheumatic drugs and biological agents are being applied in clinical practice. However, long-term use of these drugs causes side effects, and some RA patients may acquire resistance to these drugs. In this regard, recently investigated MSC-based therapy is considered as a promising approach in RA treatment. In this study, we review conventional and modern treatment approaches, such as MSC-based therapy through the understanding of the link between MSCs and the innate and adaptive immune systems. Moreover, we discuss recent achievements in preclinical and clinical studies as well as various strategies for the enhancement of MSC immunoregulatory properties.

Psoriatic disease is associated with systemic inflammation, endothelial activation, and altered haemostatic function

Psoriasis is a chronic, immune-mediated inflammatory skin disease, affecting approximately 2% of the general population, which can be accompanied by psoriatic arthritis (PsA). The condition has been associated with an increased cardiovascular burden. Hypercoagulability is a potential underlying mechanism that may contribute to the increased risk of major cardiovascular events in psoriatic individuals. Whole blood samples were collected from 20 PsA patients and 20 healthy individuals. The concentrations of inflammatory molecules (C-reactive protein, serum amyloid A, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and soluble P-selectin) were determined by enzyme-linked immunosorbent assays. In addition, clotting efficiency was evaluated by thromboelastography. The fibrin network architecture was also assessed by scanning electron microscopy. Elevated levels of circulating inflammatory molecules were significantly associated with the presence of psoriatic disease. Furthermore, an increased tendency towards thrombus formation was significantly predictive of disease presence. Scanning electron microscopy revealed that fibrin clots were denser in psoriatic individuals, compared to healthy controls, with an increased fibrin fibre diameter associated with psoriatic disease. Our results add to the accumulating evidence of the systemic nature of psoriasis and the subsequent risk of cardiovascular comorbidities, potentially due to an acquired hypercoagulability. We suggest that haemostatic function should be monitored carefully in psoriatic patients that present with severe disease, due to the pre-eminent risk of developing thrombotic complications.

Mitochondria as Key Players in the Pathogenesis and Treatment of Rheumatoid Arthritis

Mitochondria are major energy-producing organelles that have central roles in cellular metabolism. They also act as important signalling hubs, and their dynamic regulation in response to stress signals helps to dictate the stress response of the cell. Rheumatoid arthritis is an inflammatory and autoimmune disease with high prevalence and complex aetiology. Mitochondrial activity affects differentiation, activation and survival of immune and non-immune cells that contribute to the pathogenesis of this disease. This review outlines what is known about the role of mitochondria in rheumatoid arthritis pathogenesis, and how current and future therapeutic strategies can function through modulation of mitochondrial activity. We also highlight areas of this topic that warrant further study. As producers of energy and of metabolites such as succinate and citrate, mitochondria help to shape the inflammatory phenotype of leukocytes during disease. Mitochondrial components can directly stimulate immune receptors by acting as damage-associated molecular patterns, which could represent an initiating factor for the development of sterile inflammation. Mitochondria are also an important source of intracellular reactive oxygen species, and facilitate the activation of the NLRP3 inflammasome, which produces cytokines linked to disease symptoms in rheumatoid arthritis. The fact that mitochondria contain their own genetic material renders them susceptible to mutation, which can propagate their dysfunction and immunostimulatory potential. Several drugs currently used for the treatment of rheumatoid arthritis regulate mitochondrial function either directly or indirectly. These actions contribute to their immunomodulatory functions, but can also lead to adverse effects. Metabolic and mitochondrial pathways are attractive targets for future anti-rheumatic drugs, however many questions still remain about the precise role of mitochondrial activity in different cell types in rheumatoid arthritis.

Apigenin alleviates methotrexate-induced liver and kidney injury in mice

Methotrexate (MTX) is a drug used in the treatment of various types of cancer and inflammatory diseases, but its clinical use has been restricted due to its toxicity. Apigenin (API) is an effective flavonoid with antioxidant and anti-inflammatory properties. The aim of this study was to determine the protective effect of API against MTX-induced liver and kidney toxicity. Four groups with 12 male mice each were used. The control and API groups were received 0.9% saline (ip) and API (3 mg/kg ip) for 4 days, respectively. The MTX group were given a single dose of MTX (20 mg/kg ip) on the fourth day. The MTX + API group were administered API for 7 days and then MTX on fourth day. Blood, liver and kidney were collected to evaluate tissue injury markers, oxidative stress biomarkers, and histopathological and immunohistochemical assessments. In MTX-treated group, significant increases in aminotransferases activities, creatinine and malondialdehyde (MDA) levels and significant decreases in catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase1 (SOD1) activities and glutathione (GSH) levels were determined compared to the control group. Furthermore, histopathological changes and significant increases in caspase-3, C-reactive protein (CRP), granulocyte colony-stimulating factor (G-CSF), and inducible nitric oxide synthase (iNOS) expressions were detected in both liver and kidney tissues of MTX-treated mice. Pretreatment with API alleviates liver and kidney toxicity by attenuating oxidative stress and tissue injury markers, histopathological alterations, and apoptosis and inflammation. These results suggest that API has a protective effect against oxidative stress and liver-kidney toxicity induced by MTX.

Naringin alleviates methotrexate-induced liver injury in male albino rats and enhances its antitumor efficacy in HepG2 cells

Methotrexate (MTX) is an efficient chemotherapeutic and immunosuppressant drug, but the hepatotoxicity of MTX limits its clinical use. Naringin (Nar) is a flavonoid derived from Citrus paradise, and has been shown to possess several pharmacological activities, including free-radical scavenging and antioxidant properties. In the present study, we first tested the possible protective effects of multiple doses of Nar against MTX-induced acute hepatotoxicity in rats, and then we investigated the growth inhibition and apoptotic effects of MTX and/or Nar against the HepG2 hepatocarcinoma cell line. Our in vivo results showed that Nar significantly reduced MTX-induced increases in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin levels. Nar also reduced MTX-induced oxidative stress by significantly reducing liver malondialdehyde (MDA) and nitric oxide (NO) content and increasing superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH). In addition, Nar significantly counteracted MTX-induced increases in hepatic interleukin-6 and tumor necrosis factor-α (TNF-α). Further, Nar greatly protected hepatocyte ultrastructure against MTX-induced injury. In contrast, in vitro MTX and/or Nar treatment of HepG2 cells for 48 h exhibited a cytotoxic effect and induced apoptosis in a dose-dependent manner mediated by a significant increase in the Bax/Bcl-2 protein expression ratio. Noticeably, Nar potentiated the MTX effect on the Bax/Bcl-2 ratio. In conclusion, Nar decreased MTX-induced functional and ultrastructural liver damage in a tumor-free animal model. Also, our data introduce MTX and Nar as promising antiproliferative agents with a distinctive mode of action, inducing apoptosis in HepG2 tumor cells through activation of Bax and down-regulation of Bcl-2 protein expression.

Bisphenol AF elevates procoagulant platelets by inducing necroptosis via RIPK1-inflammasome axis

Bisphenol AF, an analogue of Bisphenol A, is an important raw material used in the production of plastic and rubber substances like plastic bottles and containers, toys, and medical supplies. Increased contamination of air, water, dust, and food with BPA/BPAF, poses an enormous threat to humans, globally. BPAF/BPA are endocrine-disrupting chemicals that mimic estrogen hormone, thus increasing the risks of various metabolic and chronic disorders. Exposure of human blood cells to BPA/BPAF induces oxidative stress and genotoxicity. However, its effects on platelets, which play central roles in hemostasis and thrombosis, are not well-documented. In this study, we demonstrate that BPAF induces RIPK1-inflammasome axis-mediated necroptosis in platelets, increasing procoagulant platelet levels in vivo and in vitro. We also show that BPAF-induced rise in procoagulant platelets worsens pulmonary thromboembolism in vivo. The elevated procoagulant platelets are shown to increase platelet-neutrophil/monocyte aggregates that mediate pathogenesis of CVD, thrombosis, and chronic inflammatory diseases. Our results demonstrate the toxic effects of BPAF on platelets and how it propagates the clinical complications by elevating procoagulant platelet numbers. Altogether, our study sends a cautionary message against extensive use of BPAF in the plastic and rubber industries, resulting in frequent human exposure to it, thus endangering platelet functions.

Glycosylation end products mediate damage and apoptosis of periodontal ligament stem cells induced by the JNK-mitochondrial pathway

Background: Recent studies have confirmed the bidirectional relationship between the two and the exacerbation of periodontitis by type II diabetes mellitus (T2DM), the pathogenic mechanism has not yet been clarified, AGEs has been linked to the pathogenesis of both periodontitis and T2DM, JNK signaling pathway might play a important role to explain the inner mechanism.

Objectives: To study advanced glycation end products (AGEs) activate the innate immune system of the host by activating oxidative stress and affecting cellular signal transduction in periodontal ligament stem cells (PDLSCs);

Results: TNF-α and/or AGEs can induce the formation of endogenous ROS in PDLSCs, thereby activating the downstream JNK signalling pathway, leading to the initiation of the mitochondria-mediated apoptotic pathway and the induction of PDLSC apoptosis.

Conclusion: we hypothesized that the JNK pathway is a key link in the apoptosis of PDLSCs mediated by TNF-α and/or AGEs.

Materials and Methods: PDLSCs from healthy volunteers were extracted, cultured and stimulated with TNF-a and/or AGEs, Flow cytometry, CCK-8, multidifferential assay, RT-PCR, apoptosis assay, Transmission electron microscopy and Western blotting were recruit to detect the internal relations between AGEs and PDLSCs.

Metabolic Targets for Treatment of Autoimmune Diseases

There is a considerable unmet demand for safe and efficacious medications in the realm of autoimmune and inflammatory diseases. The fate of the immune cells is precisely governed by control of various metabolic processes such as mitochondrial oxidative phosphorylation, glycolysis, fatty acid synthesis, beta-oxidation, amino acid metabolism, and several others including the pentose phosphate pathway, which is a unique source of metabolites for cell proliferation and maintenance of a reducing environment. These pathways are tightly regulated by the cytokines, growth factors, availability of the nutrients and host-microbe interaction. Exploring the immunometabolic pathways that govern the fate of cells of the innate and adaptive immune system, during various stages of activation, proliferation, differentiation and effector response, is crucial for new development of new treatment targets. Identifying the pathway connections and key enzymes will help us to target the dysregulated inflammation in autoimmune diseases. The mechanistic target of rapamycin (mTOR) pathway is increasingly recognized as one of the key drivers of proinflammatory responses in autoimmune diseases. In this review, we provide an update on the current understanding of the metabolic signatures noted within different immune cells of many different autoimmune diseases with a focus on selecting pathways and specific metabolites as targets for treatment.

Metabolic pathways mediate pathogenesis and offer targets for treatment in rheumatic diseases

PURPOSE OF REVIEW

The cause of autoimmune diseases remains incompletely understood. Here, we highlight recent advances in the role of proinflammatory metabolic pathways in autoimmune disease, including treatment with antioxidants and mechanistic target of rapamycin (mTOR) inhibitors.

RECENT FINDINGS

Recent studies show that mTOR pathway activation, glucose utilization, mitochondrial oxidative phosphorylation, and antioxidant defenses play critical roles in the pathogenesis of autoimmune diseases, including rheumatoid arthritis, immune thrombocytopenia, Sjögren's syndrome, large vessel vasculitis, and systemic lupus erythematosus. mTOR activity leads to Th1 and Th17 cell proliferation, Treg depletion, plasma cell differentiation, macrophage dysfunction, and increased antibody and immune complex production, ultimately resulting in tissue inflammation. mTOR also affects the function of connective tissue cells, including fibroblast-like synoviocytes, endothelial cells, and podocytes. mTOR inhibition via rapamycin and N-acetylcysteine, and blockade of glucose utilization show clinical efficacy in both mouse models and clinical trials, such as systemic lupus erythematosus.

SUMMARY

The mTOR pathway is a central regulator of growth and survival signals, integrating environmental cues to control cell proliferation and differentiation. Activation of mTOR underlies inflammatory lineage specification, and mTOR blockade-based therapies show promising efficacy in several autoimmune diseases.

MicroRNA Targeting Nicotinamide Adenine Dinucleotide Phosphate Oxidases in Cancer

Significance: Reactive oxygen species (ROS) production occurs primarily in the mitochondria as a by-product of cellular metabolism. ROS are also produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidases in response to growth factors and cytokines by normal physiological signaling pathways. NADPH oxidase, a member of NADPH oxidase (NOX) family, utilizes molecular oxygen (O₂) to generate ROS such as hydrogen peroxide and superoxide. Imbalance between ROS production and its elimination is known to be the major cause of various human diseases. NOX family proteins are exclusively involved in ROS production, which makes them attractive target(s) for the treatment of ROS-mediated diseases including cancer. Recent Advances: Molecules such as Keap1/nuclear factor erythroid 2-related factor 2 (Nrf2), N-methyl-d-aspartic acid (NMDA) receptors, nuclear factor-kappaB, KRAS, kallistatin, gene associated with retinoic-interferon-induced mortality-19, and deregulated metabolic pathways are involved in ROS production in association with NADPH oxidase. Critical Issues: Therapeutic strategies targeting NADPH oxidases in ROS-driven cancers are not very effective due to its complex regulatory circuit. Tumor suppressor microRNAs (miRNAs) viz. miR-34a, miR-137, miR-99a, and miR-21a-3p targeting NADPH oxidases are predominantly downregulated in ROS-driven cancers. miRNAs also regulate other cellular machineries such as Keap1/Nrf2 pathway and NMDA receptors involved in ROS production and consequently drug resistance. Here, we discuss the structure, function, and metabolic role of NADPH oxidase, NOX family protein-protein interaction, their association with other pathways, and NADPH oxidase alteration by miRNAs. Moreover, we also discuss and summarize studies on NADPH oxidase associated with various malignancies and their therapeutic implications. Future Directions: Targeting NADPH oxidases through miRNAs appears to be a promising strategy for the treatment of ROS-driven cancer.

Ellagic acid reduces methotrexate-induced apoptosis and mitochondrial dysfunction via up-regulating Nrf2 expression and inhibiting the IĸBα/NFĸB in rats

BACKGROUND

The clinical application of methotrexate (MTX), an efficacious cytotoxic drug, is restricted due to its associated liver toxicity. Ellagic acid (EA), a natural polyphenol, possesses hepatoprotective, antioxidant and anti-inflammatory properties.

OBJECTIVES

The present study seeks to address the hepatoprotective effects of Ellagic acid (EA) against MTX-mediated oxidative stress (OS) and widen our current knowledge of the underlying molecular mechanisms of MTX toxicity.

METHODS

Wistar rats were orally given EA (5 mg/kg and 10 mg/kg) for 10 successive days and at the end of the third day they were administered a single dose of MTX (20 mg/kg i.p).

RESULTS

After performing biochemical analysis, liver enzymes and malondialdehyde were significantly higher in the MTX group, indicating hepatic oxidative damage. MTX-induced OS was further confirmed with observation of events such as reactive oxygen species (ROS) overproduction, mitochondrial outer membrane potential decrease, mitochondrial swelling, cytochrome c release and caspase-3/9 increase, resulting in apoptosis. Furthermore, overexpression of pro-inflammatory factors such as nuclear factor kappa B (NF-ĸB) and interleukin 6 (IL-6) indicated the MTX-induced inflammation in MTX-treated group. Interestingly, EA was able to significantly prevent OS, mitochondrial dysfunction, apoptosis and inflammation induced by MTX. Also, EA-treated rats demonstrated significant upregulation of both nuclear factor erythroid 2-related factor 2 (Nrf2) and hemoxygenase-1 (HO-1), which were considerably downregulated in MTX-treated rats.

CONCLUSIONS

EA protects rats against MTX-induced apoptosis and mitochondrial dysfunction via up-Regulating Nrf2 and HO-1 expression and inhibiting the NF-κB signaling pathway. Therefore, EA may protect patients against MTX-induced hepatotoxicity and encourage its clinical application. Graphical abstract Beneficial effect of Ellagic acid (EA) on Methotrexate (MTX)-induced liver injury: molecular mechanism.

Methotrexate an Old Drug with New Tricks

Methotrexate (MTX) is the first line drug for the treatment of a number of rheumatic and non-rheumatic disorders. It is currently used as an anchor disease, modifying anti-rheumatic drug in the treatment of rheumatoid arthritis (RA). Despite the development of numerous new targeted therapies, MTX remains the backbone of RA therapy due to its potent efficacy and tolerability. There has been also a growing interest in the use of MTX in the treatment of chronic viral mediated arthritis. Many viruses-including old world alphaviruses, Parvovirus B19, hepatitis B/C virus, and human immunodeficiency virus-have been associated with arthritogenic diseases and reminiscent of RA. MTX may provide benefits although with the potential risk of attenuating patients' immune surveillance capacities. In this review, we describe the emerging mechanisms of action of MTX as an anti-inflammatory drug and complementing its well-established immunomodulatory activity. The mechanisms involve adenosine signaling modulation, alteration of cytokine networks, generation of reactive oxygen species and HMGB1 alarmin suppression. We also provide a comprehensive understanding of the mechanisms of MTX toxic effects. Lastly, we discussed the efficacy, as well as the safety, of MTX used in the management of viral-related rheumatic syndromes.

Protective Effect and Mechanisms of New Gelatin on Chemotherapy-Induced Hematopoietic Injury Zebrafish Model

The aim of the study is to explore the protective effect of new gelatin (NG, Xin'ejiao in China) on hematopoietic injury caused by chemotherapy. Zebrafish, at 48 hours post fertilization (hpf), was treated with different chemotherapeutic drugs to establish the zebrafish hematopoietic damage model with reduced thrombocytes and erythrocytes. The protecting effects of NG on the thrombocytes and erythrocytes were observed, respectively, on zebrafish models. Then, the RT-PCR method was used to detect the change of mRNA level of the hematopoiesis-related cytokines scl1, c-myb, pu.1, GATA1, and runx1 genes. The results showed that 50 μg·mL⁻¹ and 100 μg·mL⁻¹ NG rescued and increased the thrombocytes numbers induced by vinorelbine (NVB) and chloramphenicol (CHL) and the erythrocytes numbers induced by methotrexate (MTX), doxorubicin (ADM), and mechlorethamine hydrochloride (MH) in zebrafish models. Meanwhile, the mRNA expression of scl1, c-myb, and GATA1 genes in the NG treatment group was raised compared with the MTX treatment group. Also, the mRNA expression of pu.1 and Runx1 in the NG treatment group was reduced compared with the MTX treatment group. In consequence, traditional Chinese medicine NG showed a certain degree protective effect on hematopoiesis injury induced by chemotherapy in this study, which may depend on the promotion of erythrocytes proliferation and the regulation of the hematopoietic genes level.

Resveratrol alleviates inflammatory injury and enhances the apoptosis of fibroblast‑like synoviocytes via mitochondrial dysfunction and ER stress in rats with adjuvant arthritis

Resveratrol, a bioactive compound predominantly found in grapes and red wine, provides a wide range of properties that are beneficial for health, including anticancer and anti-inflammatory activities. Previously published studies have addressed the potential therapeutic effects of resveratrol on rheumatoid arthritis (RA); however, the subcellular mechanism remains to be fully elucidated. In the present study, the therapeutic effects of resveratrol on adjuvant arthritis (AA) in Sprague-Dawley rats were investigated, and the mechanisms of resveratrol-induced apoptosis in fibroblast-like synoviocytes (FLSs) were further examined. Based on the findings, resveratrol treatment over a 12-day period led to a reduction in paw swelling and arthritis scores at the macroscopic level, and an attenuation of inflammatory cell infiltration and synovial hyperplasia, upon a histopathological examination of the AA rats. Furthermore, the administration of resveratrol triggered decreases in the expression of interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor-α (TNF-α) and an increase in the expression of IL-10, alleviating inflammatory injury in AA rats in a dose-dependent manner. In addition, resveratrol was revealed to induce the apoptosis of FLSs when administered with 5 µM H₂O₂ as determined by elevated levels of Bax, caspase-3, caspase-12 and C/EBP-homologous protein, and the downregulation of B-cell lymphoma 2 (Bcl-2), suggesting that resveratrol is able to induce apoptosis in FLSs via the mitochondrial pathway and endoplasmic reticulum (ER) stress in a milieu containing 5 µM H₂O₂. Furthermore, JC-1 was used as a fluorescent probe to detect the mitochondrial membrane potential (Δψm), and resveratrol was shown to reduce the Δψm in FLSs in the presence of 5 µM H₂O₂. However, resveratrol was not able to trigger intracellular calcium overload, although it did suppress ATP- and thapsigargin-induced calcium release from the ER. In conclusion, the present study revealed that resveratrol was able to alleviate inflammatory injury in AA rats, triggering the apoptosis of FLSs via the mitochondrial pathway and ER stress. These results provide a theoretical basis for future treatments using resveratrol for RA.

The in vitro effect of antirheumatic drugs on platelet function

Several antirheumatic drugs lower the cardiovascular risk among rheumatoid arthritis patients. It is, however, unknown whether inhibition of platelet function contributes to this risk reduction. Only few studies have investigated the potential role of platelets as a target of antirheumatic drugs. In this study, platelet function was tested in vitro in samples from 24 healthy individuals spiked with antirheumatic drugs in clinically relevant concentrations or vehicle. Platelet aggregation was tested with 96-well light transmission aggregometry (LTA), and when an effect ≥20% compared to vehicle was observed, flow cytometric platelet aggregation and activation were evaluated and closure time was measured by Platelet Function Analyzer (PFA-200). When evaluated by LTA, teriflunomide (the active metabolite of leflunomide), tocilizumab, and prednisolone reduced ADP- and collagen-induced platelet aggregation ≥20%, while adalimumab increased TRAP-induced platelet aggregation ≥20%. Using flow cytometry, agonist-induced platelet aggregation with teriflunomide or vehicle was mean ± standard deviation (SD); 30.7% ± 5.8 vs. 41.7% ± 6.5, p = 0.02 using ADP, and 34.7% ± 13.9 vs. 55.8% ± 3.9, p = 0.01 using collagen. Results indicate that teriflunomide, prednisolone, and tocilizumab inhibit, and adalimumab increases platelet aggregation. The study suggests that the majority of antirheumatic drugs mainly reduced cardiovascular risk through indirect effects (e.g., reducing inflammation).

Para-tertiary butyl catechol (PTBC), an industrial antioxidant induces human platelet apoptosis

The catecholic derivative para-tertiary butyl catechol (PTBC) is a conventional antioxidant and polymerization inhibitor, which exhibits melanocytotoxic effects and contact dermatitis often leading to occupational leucoderma or vitiligo. Although numerous industrial workers will be in constant exposure to PTBC and its chances of getting entry into blood are most expected, its effect on blood components is still undisclosed. As platelets play a prominent role in dermatitis, inflammation, and immunity, in this study we have evaluated the effect of PTBC on human platelets in vitro. Exposure of platelets to PTBC showed increased reactive oxygen species (ROS), intracellular calcium, cardiolipin oxidation, mitochondrial permeability transition pore (MPTP) formation, activation of caspases, phosphatidylserine (PS) externalization and decreased mitochondrial membrane potential. In addition, there was a significant decrease in cellular glutathione level, increased γ-glutamyltransferase (GGT) activity and cell death. These findings demonstrate that PTBC could induce toxic effects on blood components, which is often ignored field of research. Since dermal exposure of humans to toxic chemicals covers an important issue in various industries, there is a need of such work to understand and update the long-term toxicities induced by PTBC usage in industrial sectors and public domain.

Berberine mitigates high glucose-potentiated platelet aggregation and apoptosis by modulating aldose reductase and NADPH oxidase activity

Diabetes mellitus (DM) is a serious metabolic disorder affecting millions of people worldwide. The high rate of mortality and morbidity during DM is attributed to the increased atherothrombotic events due to platelet activation and apoptosis leading to macro and micro vascular occlusions. The platelet hyper-reactivity and apoptosis during DM is accounted for the accumulated reactive oxygen species (ROS) due to increased aldose reductase (AR) and NADPH oxidase (NOX) activities. Considering aspirin insensitivity in DM patients, new therapies targeting the underlying mechanism is urgently warranted. Berberine, a benzylisoquinoline alkaloids, from Chinese folk medicine has been demonstrated with several anti-diabetic effects. Therefore, we evaluated whether berberine inhibits high glucose potentiated platelet aggregation, apoptosis and further evaluated the mechanism of its action in platelets. Berberine was found to inhibit platelet aggregation, superoxide production via modulating AR, NOX, and glutathione reductase activities in high glucose (HG) treated platelets. Correlated with this, berberine inhibited, calcium release, ERK activation, α- and dense granule release and platelet adhesive properties. In addition, berberine inhibited p38-p53 mediated BAX activation, mitochondrial dysfunction and platelet apoptosis induced by HG. The platelet protective effect of berberine by inhibiting AR and NOX in high glucose-treated platelets suggest that berberine could be developed as a potential therapeutic molecule in the treating pathologies associated with DM.

HIV-1 Tat and methamphetamine co-induced oxidative cellular injury is mitigated by N-acetylcysteine amide (NACA) through rectifying mTOR signaling

Methamphetamine (Meth) is an addictive psychostimulant whose abuse is intimately linked to increased risks for HIV-1 infection. Converging lines of evidence indicate that Meth also aggravates the symptoms of HIV-associated neurocognitive disorders (HAND), though the underlying mechanisms remain poorly understood. By using the lipophilic antioxidant N-acetylcysteine amide (NACA) as an interventional agent, we examined the roles of oxidative stress in autophagy and apoptosis induced by HIV-Tat (the transactivator of transcription), Meth or their combined treatment in human SH-SY5Y neuroblastoma cells and in the rat striatum. Oxidative stress was monitored in terms of the production of intracellular reactive oxygen species (ROS) and antioxidant reserves including glutathione peroxidase (GPx) and Cu,Zn-superoxide dismutase (SOD). NACA significantly reduced the level of ROS and restored GPx and SOD to levels comparable to that of normal control, implying a cytoprotective effect of NACA against oxidative stress elicited by Tat- and/or Meth. Protein expression of mammalian target of rapamycin (mTOR) was measured in SH-SY5Y cells and in the rat striatum to further explore the underlying mechanism of NACA protect against oxidative stress. The results support a beneficial effect of NACA in vivo and in vitro through rectification of the mTOR signaling pathway. Collectively, our study shows that NACA protects against Meth and/or Tat-induced cellular injury in vitro and in the rat striatum in vivo by attenuating oxidative stress, apoptosis and autophagy, at least in part, via modulation of mTOR signaling.

Side effects of methotrexate therapy for rheumatoid arthritis: A systematic review

Methotrexate (MTX) is used as an anchor disease-modifying anti-rheumatic drugs (DMARDs) in treating rheumatoid arthritis (RA) because of its potent efficacy and tolerability. MTX benefits a large number of RA patients but partially suffered from side effects. A variety of side effects can be associated with MTX when treating RA patients, from mild to severe or discontinuation of the treatment. In this report, we reviewed the possible side effects that MTX might cause from the most common gastrointestinal toxicity effects to less frequent malignant diseases. In order to achieve regimen with less side effects, the administration of MTX with appropriate dose and a careful pretreatment inspection is necessary. Further investigations are required when combining MTX with other drugs so as to enhance the efficacy and reduce side effects at the same time. The management of MTX treatment is also discussed to provide strategies for occurred side effects. Thus, this review will provide scholars with a comprehensive understanding the side effects of MTX administration by RA patients.

Aggregation is impaired in starved platelets due to enhanced autophagy and cellular energy depletion

Platelet hyperactivity is the hallmark of thrombosis and hemostasis disorders including atherosclerosis, diabetes, stroke, arthritis, and cancer causing significant mortality and morbidity. Therefore, regulating platelet hyperactivity is an ever growing interest. Very recently, basal autophagic process has been demonstrated to be essential for normal functioning of platelets. However, autophagy can be elevated above basal level under conditions like starvation, and how platelets respond in these settings remains to be elucidative. Therefore, in this study we demonstrate a substantial autophagy induction (above basal level) by starvation, which decreases platelet aggregation responses to various agonists. The decreased aggregation in starved platelets was restored in combination with autophagy inhibitors (3-methyladenine and NH₄Cl) and acetate supplementation. Starved platelets also showed decreased calcium mobilization, granule release, and adhesive properties. Furthermore, ex vivo platelets obtained from starved rats showed increased autophagy markers and decreased aggregation responses to various agonists. Our results distinctly explain that enhanced autophagy and cellular energy depletion are the cause for decreased platelet activation and aggregation. The study emphasizes the cardinal role of starvation and autophagy in the management of diseases and disorders associated with platelet hyperactivity.

Metabolism as a Target for Modulation in Autoimmune Diseases

Metabolic pathways are now well recognized as important regulators of immune differentiation and activation, and thus influence the development of autoimmune diseases such as systemic lupus erythematosus (SLE). The mechanistic target of rapamycin (mTOR) has emerged as a key sensor of metabolic stress and an important mediator of proinflammatory lineage specification. Metabolic pathways control the production of mitochondrial reactive oxygen species (ROS), which promote mTOR activation and also modulate the antigenicity of proteins, lipids, and DNA, thus placing ROS at the heart of metabolic disturbances during pathogenesis of SLE. Therefore, we review here the pathways that control ROS production and mTOR activation and identify targets for safe therapeutic modulation of the signaling network that underlies autoimmune diseases, focusing on SLE.

Cancer chemotherapeutics in rheumatoid arthritis: A convoluted connection

Chemotherapy is one of the most popular therapeutic strategies to treat cancer. However, cancer chemotherapeutics have often been associated with impairment of the immune system, which might consequently lead to an augmented risk of autoimmune disorders, such as rheumatoid arthritis. Though the accurate mechanistic facets of rheumatoid arthritis induction have not been interpreted yet, a conglomeration of genetic and environmental factors might promote its etiology. What makes the scenario more challenging is that patients with rheumatoid arthritis are at a significantly elevated risk of developing various types of cancer. It is intriguing to note that diverse cancer chemotherapy drugs are also commonly used to treat symptoms of rheumatoid arthritis. However, a colossal multitude of such cancer therapeutics has demonstrated highly varied results in rheumatoid arthritis patients, including both beneficial and adverse effects. Herein, we attempt to present a holistic account of the variegated modalities of this complex tripartite cross-talk between cancer, rheumatoid arthritis and chemotherapy drugs in order to decode the sinuous correlation between these two appalling pathological conditions.

Drug-induced thrombocytopenia: Focus on platelet apoptosis

Thrombocytopenia is a serious and potentially fatal complication of drug therapy that results either from a decrease in bone marrow platelet production or the excessive destruction of circulating platelets. Although multiple mechanisms are responsible for deregulated platelet clearance, the role of programmed platelet death (apoptosis) in drug-induced thrombocytopenia has been relatively under-investigated until recently. Here we review apoptotic signaling pathways in platelets, with a focus on current data that provide mechanistic insights into drug-induced apoptosis and thrombocytopenia.

Inhibition of constitutive NF-κB activity induces platelet apoptosis via ER stress

Platelets are anucleate cells, known for their pivotal roles in hemostasis, inflammation, immunity, and disease progression. Being anuclear, platelets are known to express several transcriptional factors which exert nongenomic functions, including the positive and negative regulation of platelet activation. NF-κB is one such transcriptional factor involved in the regulation of genes for survival, proliferation, inflammation and immunity. Although, the role NF-κB in platelet activation and aggregation is partially known, its function in management of platelet survival and apoptosis remain unexplored. Therefore, two unrelated inhibitors of NF-κB activation, BAY 11-7082 and MLN4924 were used to determine the role of NF-κB in platelets. Inhibition of NF-κB caused decreased SERCA activity and increased cytosolic Ca²⁺ level causing ER stress which was determined by the phosphorylation of eIF2-α. Further, there was increased BAX and decreased BCl-2 levels, incidence of mitochondrial membrane potential depolarization, release of cytochrome c into cytosol, caspase activation, PS externalization and cell death in BAY 11-7082 and MLN4924 treated platelets. The obtained results demonstrate the critical role played by NF-κB in Ca²⁺ homeostasis and survival of platelets. In addition, the study demonstrates the potential side effects associated with NF-κB inhibitors employed during inflammation and cancer therapy.

Protective effects of phloridzin against methotrexate-induced liver toxicity in rats

BACKGROUND

Liver is the largest internal organ concerning with metabolism, hormonal balance and clarifying of the toxins. One of the main complications of methotrexate (MTX) therapy was the hepatic injury.

OBJECTIVE

This study was conducted to elucidate the possible protective effects of phloridzin (PHL) against MTX-induced hepatotoxicity as compared to standard agent N-acetylcysteine (NAC).

MATERIALS AND METHODS

Rats were randomly divided into a normal control group, a respective group (PHL 40mg/kg/day orally (p.o.) for 10 consecutive days), a hepatotoxicity control group (MTX 20mg/kg, i.p., once), and three treated groups received NAC (150mg/kg/day; a reference standard), PHL (40mg/kg/day) and PHL (80mg/kg/day) p.o. for 10 consecutive days, at the end of the day 3 of the experiment rats were administered MTX. Assessed biomarkers included serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) as liver function parameters, serum tumor necrosis factor-α (TNF-α) and cyclooxygenase-II (COX-II), as inflammatory biomarkers, hepatic total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), glutathione reduced (GSH), nitrite (NO₂^-), catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) as oxidative stress biomarkers. Furthermore, hepatic caspase-3 expression was assessed. Biochemical and molecular estimations reinforced by histopathological findings.

RESULTS

Rats pre-treated with PHL significantly reduced hepatic injury, evidenced by significant reductions in ALT, AST and LDH, TNF-α and COX-II levels, significant reductions in hepatic NO₂^- and TBARS levels, and significant elevations in hepatic TAC, GSH, GST, CAT and SOD levels. Additionally, downregulation of hepatic caspase-3 expression. Finally, histopathological results consistent with our previous findings.

CONCLUSION

PHL protects against hepatic injury in rats mainly through mitigation of oxidative stress, inflammation and apoptosis in hepatic tissues and may be promising to alleviate and early treatment of MTX-induced hepatoxicity in man.

Novel sila-amide derivatives of N-acetylcysteine protects platelets from oxidative stress-induced apoptosis

Oxidative stress-induced platelet apoptosis is one among the many causes for the development and progression of many disorders like cardiovascular diseases, arthritis, Alzheimer's disease and many chronic inflammatory responses. Many studies have demonstrated the less optimal effect of N-acetyl cysteine (NAC) in oxidative stress-induced cellular damage. This could be due to its less lipophilicity which makes it difficult to enter the cellular membrane. Therefore in the present study, lipophilic sila-amide derivatives (6a and 6b) synthesized through the reaction of NAC with 3-Aminopropyltrimethylsilane and aminomethyltrimethylsilane were used to determine their protective property against oxidative stress-induced platelet apoptosis. At a concentration of 10 µM, compound 6a and 6b were able to significantly inhibit Rotenone/H₂O₂ induced platelet apoptotic markers like reactive oxygen species, intracellular calcium level, mitochondrial membrane potential, cytochrome c release from mitochondrial to the cytosol, caspase-9 and -3 activity and phosphatidylserine externalization. Therefore, the compounds can be extrapolated as therapeutic agents to protect platelets from oxidative stress-induced platelet apoptosis and its associated complications.

Nephroprotective Effects of N-Acetylcysteine Amide against Contrast-Induced Nephropathy through Upregulating Thioredoxin-1, Inhibiting ASK1/p38MAPK Pathway, and Suppressing Oxidative Stress and Apoptosis in Rats

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI) due to apoptosis induced in renal tubular cells. Our previous study demonstrated the novel N-acetylcysteine amide (NACA); the amide form of N-acetyl cysteine (NAC) prevented renal tubular cells from contrast-induced apoptosis through inhibiting p38 MAPK pathway in vitro. In the present study, we aimed to compare the efficacies of NACA and NAC in preventing CIN in a well-established rat model and investigate whether thioredoxin-1 (Trx1) and apoptosis signal-regulating kinase 1 (ASK1) act as the potential activator for p38 MAPK. NACA significantly attenuated elevations of serum creatinine, blood urea nitrogen, and biomarkers of AKI. At equimolar concentration, NACA was more effective than NAC in reducing histological changes of renal tubular injuries. NACA attenuated activation of p38 MAPK signal, reduced oxidative stress, and diminished apoptosis. Furthermore, we demonstrated that contrast exposure resulted in Trx1 downregulation and increased ASK1/p38 MAPK phosphorylation, which could be reversed by NACA and NAC. To our knowledge, this is the first report that Trx1 and ASK1 are involved in CIN. Our study highlights a renal protective role of NACA against CIN through modulating Trx1 and ASK1/p38 MAPK pathway to result in the inhibition of apoptosis among renal cells.

Oxidative Stress Induces Mouse Follicular Granulosa Cells Apoptosis via JNK/FoxO1 Pathway

The c-Jun N-terminal protein kinase (JNK) plays an important role in the regulation of cell apoptosis. Forkhead box O (FoxO) transcription factors are involved in diverse biological processes, including cellular metabolism, cell apoptosis, and cell cycle. However, the JNK/FoxO1 pathway involved in the process of apoptosis induced by oxidative stress remains to be elucidated. Here, we demonstrated that the JNK activity significantly increased in response to oxidative stress in mouse follicular granulosa cells (MGCs). SP600125, a selective JNK inhibitor, attenuated the oxidative stress-induced MGCs apoptosis. Oxidative stress enhanced the FoxO1 nuclear translocation by activating the JNK activity. Moreover, JNK mediated the dissociation of FoxO1 from 14-3-3 proteins in MGCs after the treatment with H₂O₂. Finally, oxidative stress up-regulated the expression of FoxO1 via JNK mediation of FoxO1 self-regulation in MGCs. Taken together, our findings suggest that JNK/FoxO1 is involved in the regulation of oxidative stress-induced cell apoptosis in MGCs.

Mechanical perturbations trigger endothelial nitric oxide synthase activity in human red blood cells

Nitric oxide (NO), a vascular signaling molecule, is primarily produced by endothelial NO synthase. Recently, a functional endothelial NO synthase (eNOS) was described in red blood cells (RBC). The RBC-eNOS contributes to the intravascular NO pool and regulates physiological functions. However the regulatory mechanisms and clinical implications of RBC-eNOS are unknown. The present study investigated regulation and functions of RBC-eNOS under mechanical stimulation. This study shows that mechanical stimuli perturb RBC membrane, which triggers a signaling cascade to activate the eNOS. Extracellular NO level, estimated by the 4-Amino-5-Methylamino-2', 7'-Difluorofluorescein Diacetate probe, was significantly increased under mechanical stimuli. Immunostaining and western blot studies confirmed that the mechanical stimuli phosphorylate the serine 1177 moiety of RBC-eNOS, and activates the enzyme. The NO produced by activation of RBC-eNOS in vortexed RBCs promoted important endothelial functions such as migration and vascular sprouting. We also show that mechanical perturbation facilitates nitrosylation of RBC proteins via eNOS activation. The results of the study confirm that mechanical perturbations sensitize RBC-eNOS to produce NO, which ultimately defines physiological boundaries of RBC structure and functions. Therefore, we propose that mild physical perturbations before, after, or during storage can improve viability of RBCs in blood banks.

Ceramide Synthase 6 Is a Novel Target of Methotrexate Mediating Its Antiproliferative Effect in a p53-Dependent Manner

We previously reported that ceramide synthase 6 (CerS6) is elevated in response to folate stress in cancer cells, leading to enhanced production of C₁₆-ceramide and apoptosis. Antifolate methotrexate (MTX), a drug commonly used in chemotherapy of several types of cancer, is a strong inhibitor of folate metabolism. Here we investigated whether this drug targets CerS6. We observed that CerS6 protein was markedly elevated in several cancer cell lines treated with MTX. In agreement with the enzyme elevation, its product C₁₆-ceramide was also strongly elevated, so as several other ceramide species. The increase in C₁₆-ceramide, however, was eliminated in MTX-treated cells lacking CerS6 through siRNA silencing, while the increase in other ceramides sustained. Furthermore, the siRNA silencing of CerS6 robustly protected A549 lung adenocarcinoma cells from MTX toxicity, while the silencing of another ceramide synthase, CerS4, which was also responsive to folate stress in our previous study, did not interfere with the MTX effect. The rescue effect of CerS6 silencing upon MTX treatment was further confirmed in HCT116 and HepG2 cell lines. Interestingly, CerS6 itself, but not CerS4, induced strong antiproliferative effect in several cancer cell lines if elevated by transient transfection. The effect of MTX on CerS6 elevation was likely p53 dependent, which is in agreement with the hypothesis that the protein is a transcriptional target of p53. In line with this notion, lometrexol, the antifolate inducing cytotoxicity through the p53-independent mechanism, did not affect CerS6 levels. We have also found that MTX induces the formation of ER aggregates, enriched with CerS6 protein. We further demonstrated that such aggregation requires CerS6 and suggests that it is an indication of ER stress. Overall, our study identified CerS6 and ceramide pathways as a novel MTX target.

Activation of mTOR (mechanistic target of rapamycin) in rheumatic diseases

Mechanistic target of rapamycin (mTOR, also known as mammalian target of rapamycin) is a ubiquitous serine/threonine kinase that regulates cell growth, proliferation and survival. These effects are cell-type-specific, and are elicited in response to stimulation by growth factors, hormones and cytokines, as well as to internal and external metabolic cues. Rapamycin was initially developed as an inhibitor of T-cell proliferation and allograft rejection in the organ transplant setting. Subsequently, its molecular target (mTOR) was identified as a component of two interacting complexes, mTORC1 and mTORC2, that regulate T-cell lineage specification and macrophage differentiation. mTORC1 drives the proinflammatory expansion of T helper (TH) type 1, TH17, and CD4(-)CD8(-) (double-negative, DN) T cells. Both mTORC1 and mTORC2 inhibit the development of CD4(+)CD25(+)FoxP3(+) T regulatory (TREG) cells and, indirectly, mTORC2 favours the expansion of T follicular helper (TFH) cells which, similarly to DN T cells, promote B-cell activation and autoantibody production. In contrast to this proinflammatory effect of mTORC2, mTORC1 favours, to some extent, an anti-inflammatory macrophage polarization that is protective against infections and tissue inflammation. Outside the immune system, mTORC1 controls fibroblast proliferation and chondrocyte survival, with implications for tissue fibrosis and osteoarthritis, respectively. Rapamycin (which primarily inhibits mTORC1), ATP-competitive, dual mTORC1/mTORC2 inhibitors and upstream regulators of the mTOR pathway are being developed to treat autoimmune, hyperproliferative and degenerative diseases. In this regard, mTOR blockade promises to increase life expectancy through treatment and prevention of rheumatic diseases.

Unconjugated Bilirubin exerts Pro-Apoptotic Effect on Platelets via p38-MAPK activation

Thrombocytopenia is one of the most frequently observed secondary complications in many pathological conditions including liver diseases, where hyperbilirubinemia is very common. The present study sought to find the cause of thrombocytopenia in unconjugated hyperbilirubinemic conditions. Unconjugated bilirubin (UCB), an end-product of heme catabolism, is known to have pro-oxidative and cytotoxic effects at high serum concentration. We investigated the molecular mechanism underlying the pro-apoptotic effect of UCB on human platelets in vitro, and followed it up with studies in phenylhydrazine-induced hyperbilirubinemic rat model and hyperbilirubinemic human subjects. UCB is indeed found to significantly induce platelet apoptotic events including elevated endogenous reactive oxygen species generation, mitochondrial membrane depolarization, increased intracellular calcium levels, cardiolipin peroxidation and phosphatidylserine externalization (p < 0.001) as evident by FACS analysis. The immunoblots show the elevated levels of cytosolic cytochrome c and caspase activation in UCB-treated platelets. Further, UCB is found to induce mitochondrial ROS generation leading to p38 activation, followed by downstream activation of p53, ultimately resulting in altered expression of Bcl-2 and Bax proteins as evident from immunoblotting. All these parameters conclude that elevated unconjugated bilirubin causes thrombocytopenia by stimulating platelet apoptosis via mitochondrial ROS-induced p38 and p53 activation.