Combination Of Dex Research Articles

Rapid DNA Repair in Mesenchymal Stem Cells and Bone Regeneration by Nanoparticle-Based Codelivery of Nrf2-mRNA and Dexamethasone.

Directional differentiation is a key factor determining the result of stem cell therapy. Herein, we developed a polyethylenimine (PEI)-coated poly(lactic-co-glycolic) acid (PLGA) nanoparticle (mPDN) carrying both nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and dexamethasone (Dex) to human mesenchymal stem cells (hMSCs). The combination of Dex and Nrf2-mRNA delivered by mPDN promoted the osteogenic differentiation of hMSCs. In particular, Nrf2-mRNA rapidly reduced the DNA damage caused by ROS due to early and efficient gene expression at 3 h after treatment, which was not achieved in traditional pDNA systems. High and rapid transfection, effective ROS-scavenging effect, and protection of mitochondrial dynamics were observed in hMSCs after treatment with the resulting Nrf2-mPDN. Osteogenic differentiation was also observed in 3D pellets for up to 5 weeks. Finally, the effects of rapid DNA repair in hMSCs by Nrf2-mPDN and on in vivo bone regeneration were evaluated in a rat femoral bone defect model using CT. This study demonstrated the potential of an NP-based codelivery system and efficient transfection of mRNA at early stages in hMSCs for bone regeneration and stem cell therapy.

Honokiol induces apoptosis and autophagy in dexamethasone-resistant T-acute lymphoblastic leukemia CEM-C1 cells

ABSTRACT Objective: To study whether and, if so, how honokiol overcome dexamethasone resistance in DEX-resistant CEM-C1 cells. Methods: We investigated the effect of honokiol (0–20 µM) on cell proliferation, cell cycle, cell apoptosis and autophagy in DEX-resistant CEM-C1 cells and DEX-sensitive CEM-C7 cells. We also determined the role of c-Myc protein and mRNA in the occurrence of T-ALL associated dexamethasone resistance western blot and reverse transcription-qPCR (RT-qPCR) analysis. Results: Cell Counting Kit (CCK)−8 assay shows that DEX-resistant CEM-C1 cell lines were highly resistant to dexamethasone with IC50 of 364.1 ± 29.5 µM for 48 h treatment. However, upon treatment with dexamethasone in combination with 1.5 µM of honokiol for 48 h, the IC50 of CEM-C1 cells significantly decreased to 126.2 ± 12.3 µM, and the reversal fold was 2.88. Conversely, the IC50 of CEM-C7 cells was not changed combination of dexamethasone and honokiol as compared to that of CEM-C7 cells treated with dexamethasone alone. It has been shown that honokiol induced T-ALL cell growth inhibition by apoptosis and autophagy via downregulating cell cycle-regulated proteins (Cyclin E, CDK4, and Cyclin D1) and anti-apoptotic proteins BCL-2 and upregulating pro-apoptotic proteins Bax and led to PARP cleavage. Honokiol may overcome dexamethasone resistance in DEX-resistant CEM-C1 cell lines via the suppression of c-Myc mRNA expression. Conclusion: The combination of honokiol and DEX were better than DEX alone in DEX-resistant CEM-C1 cell lines. Honokiol may regulate T-ALL-related dexamethasone resistance by affecting c-Myc.

Synergistic effects of mesenchymal stem cell-derived extracellular vesicles and dexamethasone on macrophage polarization under inflammatory conditions.

The undesirable inflammation and the excessive M1 macrophage activity may lead to inflammatory diseases. Corticosteroids and stem cell therapy are used in clinical practice to promote anti-inflammatory responses. However, this protocol has limitations and is associated with numerous side effects. In this study, the synergistic anti-inflammatory effects of dexamethasone (Dex) and mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) were evaluated to enhance the polarization of M1 inflammatory macrophages into the anti-inflammatory (M2) phenotype. Hence, we designed different combinations of Dex and EVs using three methods, including EVs isolated from Dex-preconditioned MSCs (Pre-Dex-EVs), EVs loaded with Dex (L-Dex-EVs), and EVs and Dex co-administration (Dex + EVs). All designed EVs had a significant effect on reducing the expression of M1-related genes (iNOS, Stat1, and IRF5), cytokines (IL6 and TNF-a), and CD markers (CD86) in lipopolysaccharide-stimulated macrophages. On the other hand, these combinations promoted the expression of alternative-activated M2-related genes (Arg-1, Stat6, and IRF4), cytokine (IL10), and CD markers (CD206).The combination of Dex and MSC-EVs enhances the effectiveness of both and synergistically promotes the conversion of inflammatory macrophages into an anti-inflammatory state.

The postbiotic sodium butyrate synergizes the antiproliferative effects of dexamethasone against the AGS gastric adenocarcinoma cells.

A growing body of literature underlines the fundamental role of gut microbiota in the occurrence, treatment, and prognosis of cancer. In particular, the activity of gut microbial metabolites (also known as postbiotics) against different cancer types has been recently reported in several studies. However, their in-depth molecular mechanisms of action and potential interactions with standard chemotherapeutic drugs remain to be fully understood. This research investigates the antiproliferative activities of postbiotics- short-chain fatty acid (SCFA) salts, specifically magnesium acetate (MgA), sodium propionate (NaP), and sodium butyrate (NaB), against the AGS gastric adenocarcinoma cells. Furthermore, the potential synergistic interactions between the most active SCFA salt-NaB and the standard drug dexamethasone (Dex) were explored using the combination index model. The molecular mechanisms of the synergy were investigated using reactive oxygen species (ROS), flow cytometry and biochemometric and liquid chromatography-mass spectrometry (LC-MS)-driven proteomics analyses. NaB exhibited the most significant inhibitory effect (p < 0.05) among the tested SCFA salts against the AGS gastric cancer cells. Additionally, Dex and NaB exhibited strong synergy at a 2:8 ratio (40 μg/mL Dex + 2,400 μg/mL NaB) with significantly greater inhibitory activity (p < 0.05) compared to the mono treatments against the AGS gastric cancer cells. MgA and NaP reduced ROS production, while NaB exhibited pro-oxidative properties. Dex displayed antioxidative effects, and the combination of Dex and NaB (2,8) demonstrated a unique pattern, potentially counteracting the pro-oxidative effects of NaB, highlighting an interaction. Dex and NaB individually and in combination (Dex:NaB 40:2400 μg/mL) induced significant changes in cell populations, suggesting a shift toward apoptosis (p < 0.0001). Analysis of dysregulated proteins in the AGS cells treated with the synergistic combination revealed notable downregulation of the oncogene TNS4, suggesting a potential mechanism for the observed antiproliferative effects. These findings propose the potential implementation of NaB as an adjuvant therapy with Dex. Further investigations into additional combination therapies, in-depth studies of the molecular mechanisms, and in vivo research will provide deeper insights into the use of these postbiotics in cancer, particularly in gastric malignancies.

Combination Chemotherapy in Patients with Newly Diagnosed Blastic Plasmacytoid Dendritic Cell Neoplasms (BPDCN): First Results of a Prospective French Trial (LpDessai)

Introduction Blastic plasmacytoid dendritic cell neoplasms (BPDCN) are now well-characterized diseases clearly referenced in the 5 th edition of the World Health Organization (WHO) Classification of Tumors (2022) 1 but treatment remains a real challenge. There is no consensus on the first line treatment even if CD123 targeted therapies are available in the USA and some European countries. Standard chemotherapy remains largely used as first line treatment with better results of leukemia-based regimens despite a high toxicity rate in this frail population 2,3. To establish a reference chemotherapy scheme, we prospectively evaluated the efficacy and toxicity of a combination chemotherapy (idarubicin, methotrexate, L-asparaginase, and dexamethasone) in newly diagnosed BPDCN patients (pts) in France. Patients and methods This single stage phase II study enrolled consecutive adult pts with suspected BPDCN in participating French centers. BPDCN diagnosis was centrally reviewed for cytology and immunophenotype (IF) (Pr Garnache Ottou F, UMR RIGHT BESANCON) and if needed for histology (Dr Petrella T, Montréal, Canada) according to published recommendations 1,4. After giving their informed consent, patients were evaluated for tumoral involvement by PET-scan, systematic lumbar puncture, and the mSWAT score was calculated for skin extension. Patients then received three 21 days-cycles of Ida/Metho/L-asp/Dex combination, before evaluation. Eligible patients with complete response (CR), complete response with incomplete bone marrow recovery (CRi) or partial response (PR) underwent allogeneic hematopoietic stem cell transplantation (HCT). Those not eligible received consolidation chemotherapy with 28 days cycles of Metho/L-asp/Dex (Figure 1). The primary objective was the proportion of patients with CR after 3 cycles of chemotherapy. Secondary objectives were the proportion of patients with an objective response (ORR) defined as CR, CRi or PR, the minimal residual disease (MRD) in responding patients evaluated by the presence of plasmacytoid dendritic cell blast measured by flow cytometry in the bone marrow, the incidence of severe adverse events and overall survival (OS). The competent ethics committee (Comité de Protection des Personnes Île de France 8) approved the study. The Besançon University hospital promoted the trial, financed by a grant of the French National Cancer Institute (INCa-DGOS_11093). Results Twenty-eight pts, originating from 16 centers, were screened between May 2019 and March 2023. Two patients with a misdiagnosis were screen failures. Two patients did not receive the planned chemotherapy due to clinical deterioration; 24 patients (21 male, 3 female) received at least one chemotherapy cycle and 23 are analyzed with a current end-point on June 30, 2023. Median age was 65y (21-79y). ECOG status was 0-1 in 20 cases, and 2 in 3 cases. A cutaneous involvement was identified in 16 pts (70%) and an extra medullary involvement was present in 13 (62%) pts: spleen, n= 6 (25%); lymph nodes, n= 7 (30%). Twenty-three pts (90%) had a bone marrow infiltration (identified only on IF in 4 cases), and 3 cases (14%) a documented central nervous system involvement. Nine pts had to stop planned treatment due to severe adverse events (3 deaths, 4 acute renal failure and 2 grade 4 febrile neutropenia) and in 4 pts, at least one cycle had to be delayed. Among the 15 pts receiving at least 3 cycles, 12 (80% and 50% of the whole cohort) were in ORR (CR = 8, CRi = 2, PR = 2) after the 3rd cycle of chemotherapy, 2 pts did not respond. Eight of ten (80%) CR/CRi pts had a MRD &amp;lt; 10 -4 without any further relapse. Nine of 12 responding patients (75%) received an allogeneic HCT 1-2 months after the end of the 3 rd cycle. Global OS at 6 months for responding or failing pts were 100% and 37% respectively (Figure 2). Conclusion In selected pts, an adapted chemotherapy could offer high CR rate in pts able to follow the planned treatment but remains toxic in frail pts, with only half of the them achieving a 3 rd cycle of chemotherapy. We confirm that pts achieving ORR and receiving HCT obtain prolonged CR. MRD level seems to correlate with OS and could be a useful tool to manage treatment toxicity in BPDCN frail pts.

Dexmedetomidine combined with propofol attenuates myocardial ischemia/reperfusion injury by activating the AMPK signaling pathway

ObjectiveMyocardial ischemia/reperfusion (MI/R) injury is a major cause of cardiac tissue damage, with high disability and death rates. Although both dexmedetomidine (Dex) and propofol (PPF) have been indicated to alleviate MI/R injury in rat models, the effects of the combined use of these two drugs remain unclear. This study aimed to investigate the combined effects of Dex and PPF against MI/R injury and related mechanisms. MethodsA rat model of MI/R injury was established and used to explore the combined effects of Dex and PPF on MI/R injury. Hematoxylin-eosin (HE) and Masson staining were used for histopathological evaluation. 2,3,5-triphenyltetrazolium chloride (TTC), echocardiography, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to determine myocardial infarction size, cardiac function, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) was performed to assess myocardial function and oxidative stress (OS). Autophagy was observed through transmission electron microscopy. Moreover, western blotting was conducted to detect autophagy markers and the AMPK pathway. ResultsThe combination of Dex and PPF alleviated histopathological injury, reduced myocardial infarction, and rescued cardiac dysfunction in MI/R rats. Furthermore, Dex combined with PPF decreased the levels of MDA and ROS and increased the SOD level in MI/R rats. Besides, Dex combined with PPF inhibited myocardial apoptosis in MI/R rats. After combined treatment with Dex and PPF, the number of autophagosomes, expression levels of Beclin-1 and LC3II/LC3I were elevated, while the expression levels of p62 were reduced in MI/R rats. The combined use of Dex and PPF activated the AMPK pathway in MI/R rats. Compound C (an AMPK inhibitor) could abolish the combined effects of Dex and PPF on alleviating myocardial injury and enhancing autophagy in MI/R rats. ConclusionThe combination of Dex and PPF attenuated MI/R injury in rats, which may be associated with the activation of the AMPK signaling pathway.

Efficient drug supply in stem cell cytosol via pore-forming saponin nanoparticles promotes in vivo osteogenesis and bone regeneration

Directional differentiation of stem cells is a key step in stem cell therapy. In this study, we developed saponin-based nanoparticles (Ad-SNPs) containing dexamethasone (Dex) and alpha-lipoic acid (ALA) to promote osteogenic differentiation of human mesenchymal stem cells (hMSCs) and bone regeneration. The Ad-SNPs can achieve rapid cellular uptake through a pore-forming effect without cytotoxic cationic charges. They also provide extended retention in cell cytosol due to their uptake route. These properties are advantageous in efficiently supplying drugs to the hMSCs. The combination of Dex and ALA facilitated mitochondrial fusion and prevented reactive oxygen species–induced DNA damage. It also helped to preserve mitochondrial dynamics, and the efficient supply of it provided by the Ad-SNPs induced differentiation of hMSCs into osteoblasts. The Ad-SNPs showed outstanding performance in osteoblast differentiation, maturation, and mineralization in 3D culture compared with NPs without saponin and with free drugs. When Ad-SNP-treated hMSCs were tested in a rat femoral bone defect model, they showed the fastest regeneration of bones and complete repair in the shortest period among all groups. To the best of our knowledge, this study is the first application of pore-forming saponin-based NPs with rapid cellular uptake and extended retention to stem cell therapy, and we demonstrated their promising potential in bone regeneration and efficient delivery of Dex and ALA.

P10.27.A THE INFLUENCE OF DEXAMETHASONE ON TOTAL DNA METHYLATION LEVEL IN GLIOBLASTOMA CELL LINES

Abstract BACKGROUND Dexamethasone (DEX) is a first-line antiedematic drug for glioblastoma (GBM) patients. There is also some evidence it also inhibits GBM cell proliferation and migration, thus impacting patients’ outcomes. However, other studies show that the use of DEX is associated with poor treatment outcomes in GBM patients. The exact mechanism of DEX action is unclear, and no definitive conclusion has yet been reached on its benefits in neurooncological treatment. Temozolomide (TMZ) is a first-line chemotherapeutic in GBM. Epigenetics offers a connection between genetic and environmental factors that influence the development of the disease. The best-characterized epigenetic mark is 5-methylcytosine (m5C) in DNA. The aim of that project is to show the effects of DEX administration on the total DNA methylation level. MATERIAL AND METHODS Using the nucleotide post-labeling method, we analyzed the total amount of m5C in DNA of GBM (T98G, U118, U138), cancer (HeLa) and normal (HaCaT) cell lines treated with DEX, and a combination of DEX and with TMZ. RESULTS We adjusted the DEX doses to the ones achieved in the central nervous system during treatment. We observed dose-dependent increase in total DNA methylation in all cell lines. However, the exposition of GBM cells to the combination of DEX and TMZ caused an adverse synergistic effect resulting in DNA demethylation in high doses of both drugs. In lower concentrations of both drugs DEX kept the increased DNA methylation and attenuated the demethylating effect of TMZ. CONCLUSION Total DNA methylation changes in glioma cell lines under DEX treatment suggest the new mechanism of that drug action and promote clinical implications for adjusting DEX and TMZ therapy in GBM patients. Our results show the potential and possible obstacles of the combined therapy of TMZ with DEX. Our experiments show that combined therapy with both drugs leads to total DNA hypomethylation in high doses of both drugs. Therefore the conclusion would be to adjust DEX administration during TMZ chemotherapy.

CircFOXN2 alleviates glucocorticoid- and tacrolimus-induced dyslipidemia by reducing FASN mRNA stability by binding to PTBP1 during liver transplantation.

We aimed to examine impacts and functional mechanism of circular RNA forkhead box N2 (FOXN2) in tacrolimus (TAC)- and dexamethasone (Dex)-induced lipid metabolism disorders. RNA level and protein contents in TAC, Dex, or combined TAC- plus Dex-treated patients and Huh-7 cells were measured utilizing quantitative real-time (qRT)-PCR and western blotting assays measured the formation of lipid droplet. Total cholesterol (TC) and triglyceride (TG) levels were determined using corresponding commercial kits and Oil red O staining. RNA immunoprecipitation and RNA pull-down verified the binding relationship among circFOXN2, polypyrimidine tract binding protein 1 (PTBP1) and fatty acid synthase (FASN). Male C57BL/6 mice were used to establish a dyslipidemia mouse model to validate the discoveries at the cellular level. Dex treatment significantly promoted TAC-mediated increase of TC and TG in serum samples and Huh-7 cells. Moreover, circFOXN2 was reduced but FASN was elevated in TAC-treated Huh-7 cells, and these expression trends were markedly enhanced by Dex cotreatment. Overexpression of circFOXN2 could reverse the accumulation of TC and TG and the upregulation of FASN and sterol regulatory element binding transcription factor 2 (SREBP2) mediated by Dex and TAC cotreatment. Mechanistically, circFOXN2 reduced FASN mRNA stability by recruiting PTBP1. The protective roles of circFOXN2 overexpression on lipid metabolism disorders were weakened by FASN overexpression. In vivo finding also disclosed that circFOXN2 greatly alleviated the dysregulation of lipid metabolism triggered by TAC plus Dex. CircFOXN2 alleviated the dysregulation of lipid metabolism induced by the combination of TAC and Dex by modulating the PTBP1/FASN axis.NEW & NOTEWORTHY Collectively, our experiments revealed for the first time that circFOXN2 alleviated the Dex- and TAC-induced dysregulation of lipid metabolism by regulating the PTBP1/FASN axis. These findings suggested that circFOXN2 and FASN might be candidate targets for the treatment of Dex- and TAC-induced metabolic disorders.

Change of dexmedetomidine and midazolam concentrations by simultaneous injection in an in vitro extracorporeal circuit.

Patient sedation and analgesia are vital for safety and comfort during extracorporeal membrane oxygenation (ECMO). However, adsorption by the circuit may alter drug pharmaco-kinetics and remains poorly characterized. This study is the first to examine the concentrations of DEX and MDZ in the presence of drug-drug interactions using an in vitro extracorporeal circuit system that incorporates a polymer-coated polyvinyl chloride tube, but not a membrane oxygenator. Nine in vitro extracorporeal circuits were prepared using polymer-coated PVC tubing. Once the circuits were primed and running, either a single drug or two drugs were injected as boluses into the circuit with three circuits per drug. Drug samples were drawn following injection at 2, 5, 15, 30, 60, and 120min and at 4, 12, and 24h. They were then analyzed using high-performance liquid chromatography with mass spectrometry. When compared with an injection of DEX alone, the combination of DEX and MDZ is highly changed, with DEX and MDZ affecting the availability of free drugs in the circuit. The change of DEX and MDZ concentrations was confirmed by a combination of both drugs as compared with either single-infusion DEX or MDZ in an in vitro extracorporeal circuit. Drug-drug interactions developed between DEX and MDZ through albumin in an extracorporeal circuit; as a result, the unbounded drugs might change in the circuit.

Preliminary experience on systemic effects of perineural dexamethasone sodium phosphate and methylprednisolone acetate through adductor canal block in total knee arthroplasty: A single center retrospective study.

Glucocorticoids are commonly utilised as adjuvants to enhance nerve block quality and prolong the analgesic duration. Its systemic effects, after a single-injection adductor canal block (ACB) followed by a continuous infusion, are unclear. The aim of the study was to assess the systemic effects of a single dose of dexamethasone sodium phosphate (DEX), or a combination of DEX and methylprednisolone acetate (MPA), on fasting blood glucose (FBG) and white blood cell count (WBC) when administered perineurally via ACB. A single-center retrospective study on total knee arthroplasty (TKA) was performed and a total of 95 patients were included in the final analysis. Patients were divided into three groups based on adjuvants received in ACB: Control group (N = 41) and two treatment groups, DEX group (N = 33) and DEX/MPA group (N = 21). Our primary outcomes were the change of FBG from its preoperative baseline value on postoperative day (POD) 2. The secondary outcomes included change of FBG on POD 0 and POD 1, and change of WBC on POD 0, POD 1, and POD 2. The FBG change from baseline in the DEX group was significantly higher than that in the control group (difference = 14.04, 95% CI: 1.3 to 26.77), P = 0.031) on POD 0. The WBC change from baseline in the DEX/MPA group was statistically significant higher than control on POD 0 (2.62 (1.52 to 3.37), P < 0.0001). No significant differences between DEX and DEX/MPA group were found on any given postoperative days for FBG and WBC. This study provided preliminary safety data on the use of a combination of glucocorticoids with hydrophilic (DEX) and lipophilic (MPA) properties as local anesthetic adjuvants in ACB, which induced similar levels of changes on FBG and WBC as those from both control and DEX alone group.

PS-B09-10: CANAGLIFLOZIN, A SODUIM-GLUCOSE TRANSPORTER 2 INHIBITOR IMPROVES GLUCOCORTICOID-INDUCED CARDIAC AND RENAL LIPID MISHANDLING BY SUPPRESSING LACTATE PRODUCTION IN FEMALE RATS

Evidence exist that lactate production has pathophysiological implications in the development of hyperinsulinemia-linked cardiac and renal dysfunctions. The cardio-renal protective effects of sodium-glucose co-transporter-2 inhibitor (SGLT2i) has not been associated with lactate production. The study therefore sought to test the hypothesis that SGLT2i would ameliorate insulin resistance and cardiorenal lipid mishandling by suppressing lactate production. Wistar female rats weighing between 140 and 160 g were randomly allotted into control, DEX and DEX+CANA groups (6 rats per group). The groups received (p.o.) vehicle (distilled water), dexamethasone (0.2 mg/kg) and and a combination of Dex with a SGLT2i (Canagliflozin; 10.0 mg/kg), respectively for a period of 6 days. Data showed that DEX exposure led to hyperinsulinemia, insulin resistance, elevated atherogenic plasma lipid index, accumulation of cardiac and renal triglyceride, free fatty acid, and increased lipid peroxidation in the hearts and kidneys as well as enhanced lactate production. However, the induced alterations by DEX were ameliorated by SGLT2i, CANA. Collectively, the present results demonstrate that glucocorticoid-linked hyperinsulinemia-mediated lipid mishandling in the heart and kidney is ameliorated by CANA, a SGLT2i. The implication of the findings of the study is that SGLT2i could reduce lipid accumulation in the hearts and kidneys, at least, by suppression of the lactate production

Thiol-Disulfide Exchange Coordinates the Release of Nitric Oxide and Dexamethasone for Synergistic Regulation of Intestinal Microenvironment in Colitis.

The cell-specific functions of nitric oxide (NO) in the intestinal microenvironment orchestrate its therapeutic effects in ulcerative colitis. While most biomaterials show promise by eliciting the characteristics of NO, the insufficient storage, burst release, and pro-inflammatory side effects of NO remain as challenges. Herein, we report the development of thiol-disulfide hybrid mesoporous organosilica nanoparticles (MONs) that improve the storage and sustained release of NO, broadening the therapeutic window of NO-based therapy against colitis. The tailored NO-storing nanomaterials coordinated the release of NO and the immunoregulator dexamethasone (Dex) in the intestinal microenvironment, specifically integrating the alleviation of oxidative stress in enterocytes and the reversal of NO-exacerbated macrophage activation. Mechanistically, such a synchronous operation was achieved by a self-motivated process wherein the thiyl radicals produced by NO release cleaved the disulfide bonds to degrade the matrix and release Dex via thiol-disulfide exchange. Specifically, the MON-mediated combination of NO and Dex greatly ameliorated intractable colitis compared with 5-aminosalicylic acid, even after delayed treatment. Together, our results reveal a key contribution of synergistic modulation of the intestinal microenvironment in NO-based colitis therapy and introduce thiol-disulfide hybrid nanotherapeutics for the management of inflammatory diseases and cancer.

Xuesaitong Combined with Dexmedetomidine Improves Cerebral Ischemia-Reperfusion Injury in Rats by Activating Keap1/Nrf2 Signaling and Mitophagy in Hippocampal Tissue.

Ischemic stroke is the most common type of cerebrovascular disease with high mortality and poor prognosis, and cerebral ischemia-reperfusion (CI/R) injury is the main murderer. Here, we attempted to explore the effects and mechanism of Xuesaitong (XST) combined with dexmedetomidine (Dex) on CI/R injury in rats. First, a rat model of CI/R injury was constructed via the middle cerebral artery occlusion (MCAO) method and treated with XST and Dex alone or in combination. Then, on the 5th and 10th days of treatment, the neurological impairment was assessed using the modified neurological severity scores (mNSS), the 8-arm radial maze test (8ARMT), novel object recognition test (NORT), and fear conditioning test (FCT). H&E staining was performed to observe the pathological changes of the hippocampus. ELISA and related kits were used to assess the monoamine neurotransmitters and antioxidant enzyme activities in the hippocampus. The ATP, mitochondrial membrane potential levels, and qRT-PCR of genes related to mitochondrial function were determined to assess mitochondrial functions in the hippocampus and western blot to determine Keap1/Nrf2 signaling pathway and mitophagy-related protein expression. The results showed that XST combined with Dex significantly reduced mNSS, improved spatial memory and learning deficits, and enhanced fear memory and cognitive memory ability in CI/R rats, which was superior to single-drug treatment. Moreover, XST combined with Dex treatment improved hippocampal histopathological damage; significantly increased the levels of monoamine neurotransmitters, neurotrophic factors, ATP, and mitochondrial membrane potential; and upregulated the activities of antioxidant enzymes and the expression of mitophagy-related proteins in the hippocampus of CI/R rats. XST combined with Dex treatment also activated the Keap1/Nrf2 signaling and upregulated the protein expression of downstream antioxidant enzymes HO-1 and NQ. Altogether, this study showed that a combination of XST and Dex could activate the Keap1/Nrf2 signaling and mitophagy to protect rats from CI/R-related neurological impairment.

Targeting PLZF Enhances Glucocorticoid Sensitivity in Acute Myeloid Leukemia

Glucocorticoids (GCs) are Glucocorticoid Receptor (GR) agonists that are extensively used in clinic, from management of autoimmune and inflammatory disorders to being the corner stone in treatment of adult and childhood lymphoid cancers. Unlike lymphoblastic leukemias, acute myeloid leukemia (AML) cells are generally resistant to glucocorticoids and the mechanisms underlying this resistance are yet to be elucidated. Recent efforts by our group and others suggest that certain genetic alterations, such as RUNX1 loss of function mutations, or therapy-induced stress by chemo-agents such as cytarabine or small molecules like FLT3-inhibitors could sensitize AML cells to GCs, most probably via up-regulation of glucocorticoid receptor (GR) expression. To better characterize GC-response in AML, we compared gene expression landscape of GC-resistant versus GC-sensitive AML cell lines exposed to dexamethasone (Dex) for different time points. Interestingly, we found that the number of down-regulated genes upon GC treatment is similar in both cell lines. However, GC-sensitive cell line showed 3 to 6 times more up-regulated genes following GC treatment compared to the resistant cell line. A significant portion of up-regulated genes in the sensitive cells were targets of GR transcription factor. Gene set enrichment analysis revealed up-regulation of genes associated with macrophage differentiation, inflammation, and apoptosis pathways only in the sensitive cells. To identify modulators of the GC response in AML, we conducted a genome-wide CRISPR/Cas9-based genetic screen on resistant cell lines in the presence or absence of Dex. We identified the promyelocytic leukemia zinc factor (PLZF) as a critical transcription factor that determines GC-response in AML cells. In line with this, we showed that PLZF knockdown conferred sensitivity to GC-resistant AML cells, whereas PLZF over-expression conferred resistance to the sensitive cells. Transcriptome analysis showed an overlap of up-regulated pathways between PLZF-depleted cells and GC-sensitive cells in presence of Dex including inflammation and apoptosis pathways, suggesting that PLZF depletion primes AML cells to GC-response. Furthermore, Dex treatment induced expression of a subset of GR target genes in PLZF depleted cells. Importantly, this effect was not associated with significant changes in GR global protein levels or sub-cellular distribution. PLZF has been recently shown to be a neosubstrate for Cereblon-mediated protein degradation. To define potential therapeutic strategies that target PLZF in AML, we selected two cereblon modulating molecules including Lenalidomide, which is commonly used in the clinic for treatment of hematological malignancies, and CC-3060 compound that is more potent in PLZF degradation. Combination of Dex with PLZF-degrading compounds increased cell death in a significant portion of 95 primary AML samples tested, and as expected, a broader synergistic effect was obtained with CC-3060 compound. Combination of Dex and Lenalidomide appeared more effective in samples harboring NPM1 mutation, independently of recurrent additional mutations of FLT3 or DNMT3A. Importantly, these combinations had no cytotoxicity effect on normal CD34+ cordblood cells in vitro. Current efforts are ongoing to assess efficacy of this newly identified combinatorial therapy in vivo. All together our study shows that GR trans-activating capacity is diminished in resistant AML cells leading to a failure in activating pro-differentiation and anti-leukemic genes upon Dex treatment. PLZF interferes with GC-induced cell death in AML cells at least in part via suppressing 100 of genes involved in GC-response. PLZF suppression induces inflammatory response and sensitizes AML cells to anti-inflammatory effects of glucocorticoids. Based on our results, potent PLZF degrading compounds hold promises to potentiate GC-response in AML.

Application of dexamethasone combined with tranexamic acid in perioperative period of total hip arthroplasty.

Objective:To evaluate the efficacy and safety of dexamethasone (DEXA) combined with tranexamic acid (TXA) in the perioperative period of total hip arthroplasty.Materials and Methods:A total of 100 cases were randomly divided into 2 groups (50 cases per group). All patients were given 15 mg/kg TXA before skin incision and 3 hours later. Patients in the intervention group (TXA + DEXA group) were given 20 mg dexamethasone intravenously after the onset of anesthesia, and the same dose of DEXA was administered again 24 hours later. Patients in the placebo group (TXA group) were only given the same dose of normal saline. Postoperative c-reactive protein and interleukin-6, postoperative nausea and vomiting, fatigue visual analogue scale score, postoperative length of stay, range of motion, and consumption of analgesic and antiemetics were statistically analyzed in the 2 groups.Results:The levels of c-reactive protein and interleukin-6 in the TXA + DEXA group were lower than those in the TXA group at 24, 48, 72 hours post-operatively (P < .001). Walking pain scores in the TXA + DEXA group were also significantly lower than those in the TXA group at 24 and 48 hours (P < .001); rest pain scores were lower at 24 hours (P < .001). Compared with the TXA group, the incidence of nausea VAS, postoperative nausea and vomiting, fatigue, analgesia and antiemetics consumption, postoperative length of stay, and range of motion were lower in the TXA + DEXA group (all P < .05), while there were no significant differences in postoperative hematocrit, total blood loss, and complications (P > .05).Conclusion:The combination of TXA (15 mg/kg; before skin incision and 3 hours later) and DEX (20 mg dexamethasone intravenously after the onset of anesthesia, and again 24 hours later) is an effective and safe strategy for patients undergoing total hip arthroplasty.

IFN-β mediates the anti-osteoclastic effect of bisphosphonates and dexamethasone.

Zoledronic acid (Zol) is a potent bisphosphonate that inhibits the differentiation of monocytes into osteoclasts. It is often used in combination with dexamethasone (Dex), a glucocorticoid that promotes the resolution of inflammation, to treat malignant diseases, such as multiple myeloma. This treatment can result in bone pathologies, namely medication related osteonecrosis of the jaw, with a poor understanding of the molecular mechanism on monocyte differentiation. IFN-β is a pro-resolving cytokine well-known as an osteoclast differentiation inhibitor. Here, we explored whether Zol and/or Dex regulate macrophage osteoclastic differentiation via IFN-β. RAW 264.7 and peritoneal macrophages were treated with Zol and/or Dex for 4-24h, and IFN-β secretion was examined by ELISA, while the IFN stimulated gene (ISG) 15 expression was evaluated by Western blotting. RANKL-induced osteoclastogenesis of RAW 264.7 cells was determined by TRAP staining following treatment with Zol+Dex or IFN-β and anti-IFN-β antibodies. We found only the combination of Zol and Dex increased IFN-β secretion by RAW 264.7 macrophages at 4h and, correspondingly, ISG15 expression in these cells at 24h. Moreover, Zol+Dex blocked osteoclast differentiation to a similar extent as recombinant IFN-β. Neutralizing anti-IFN-β antibodies reversed the effect of Zol+Dex on ISG15 expression and partially recovered osteoclastic differentiation induced by each drug alone or in combination. Finally, we found Zol+Dex also induced IFN-β expression in peritoneal resolution phase macrophages, suggesting these drugs might be used to enhance the resolution of acute inflammation. Altogether, our findings suggest Zol+Dex block the differentiation of osteoclasts through the expression of IFN-β. Revealing the molecular pathway behind this regulation may lead to the development of IFN-β-based therapy to inhibit osteoclastogenesis in multiple myeloma patients.

Modulation of Macrophage Response by Copper and Magnesium Ions in Combination with Low Concentrations of Dexamethasone.

Macrophages have been deemed crucial for correct tissue regeneration, which is a complex process with multiple overlapping phases, including inflammation. Previous studies have suggested that divalent ions are promising cues that can induce an anti-inflammatory response, since they are stable cues that can be released from biomaterials. However, their immunomodulatory potential is limited in a pro-inflammatory environment. Therefore, we investigated whether copper and magnesium ions combined with low concentrations of the anti-inflammatory drug, dexamethasone (dex), could have a synergistic effect in macrophage, with or without pro-inflammatory stimulus, in terms of morphology, metabolic activity and gene expression. Our results showed that the combination of copper and dex strongly decreased the expression of pro-inflammatory markers, while the combination with magnesium upregulated the expression of IL-10. Moreover, in the presence of a pro-inflammatory stimulus, the combination of copper and dex induced a strong TNF-α response, suggesting an impairment of the anti-inflammatory actions of dex. The combination of magnesium and dex in the presence of a pro-inflammatory stimulus did not promote any improvement in comparison to dex alone. The results obtained in this study could be relevant for tissue engineering applications and in the design of platforms with a dual release of divalent ions and small molecules.

Deferoxamine Inhibits Acute Lymphoblastic Leukemia Progression through Repression of ROS/HIF-1α, Wnt/β-Catenin, and p38MAPK/ERK Pathways.

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer, with a feature of easy to induce multidrug resistance and relapse. Abundant studies have proved that iron overload strengthens the growth and metastasis of tumor cells. Herein, we found that deferoxamine (DFO) effectively decreased the concentration of intracellular iron in ALL cells. DFO inhibited proliferation, induced apoptosis, and obstructed cell cycle of ALL cells, whereas DFO and dextriferron (Dex) used in combination significantly decreased the sensitivity of ALL cells to DFO. Reactive oxygen species (ROS) level was reduced in ALL cells treated with DFO, and the combination of DFO and Dex reversed the effects of DFO. In vivo, DFO inhibited mouse tumor growth. Besides, cyclinD1, β-catenin, c-Myc, hypoxia inducible factor 1 (HIF-1), p-p38MAPK, and p-ERK1/2 protein levels were significantly downregulated, and the levels of prolyl hydroxylase-2 (PHD-2) were upregulated after treated with DFO, whereas Dex treatment reversed those in vivo and in vitro. In conclusion, DFO inhibited the proliferation and ALL xenograft tumor growth, obstructed the cell cycle, and induced apoptosis of ALL cells, probably via inactivating the ROS/HIF-1α, Wnt/β-catenin, and p38MAPK/ERK signaling.

SUMOylation inhibition enhances dexamethasone sensitivity in multiple myeloma

BackgroundMultiple myeloma (MM) is an incurable plasma cell malignancy. Although Dexamethasone (Dex) is the most widely used therapeutic drug in MM treatment, patients develop Dex resistance leading to progressive disease, demanding an urgent need to investigate the mechanisms driving Dex resistance and develop new reagents to address this problem. We propose SUMOylation as a potential mechanism regulating Dex resistance and SUMOylation inhibition can enhance Dex sensitivity in MM.MethodsUsing MM cell lines and primary MM samples from relapsing MM patients, we evaluated the effects of knockdown of SUMO E1 (SAE2) or using TAK-981, a novel and specific SUMO E1 inhibitor, on Dex sensitivity. Xenograft mouse models were generated to determine the in vivo anti-MM effects of TAK-981 as a single agent and in combination with Dex. miRNA-seq, RNA-seq and GSEA analysis were utilized for evaluating key factors mediating Dex resistance. Chromatin immunoprecipitation (ChIP) assay was performed to determine the binding occupancy of c-Myc on promoter region of miRs.ResultsWe observed a significant negative correlation between SUMO E1 (SAE2) expression and Dex sensitivity in primary MM samples. Knockdown of SAE2 or using TAK-981 significantly enhances myeloma sensitivity to Dex in MM cell lines. Moreover, the enhanced anti-MM activity by TAK-981 and Dex combination has been validated using primary relapsing MM patient samples and xenograft mouse models. SUMOylation inhibition increased glucocorticoid receptor (GR) expression via downregulation miR-130b. Using RNA and microRNA sequencing, we identified miR-551b and miR-25 as important miRs mediating Dex resistance in MM. Overexpression of miR-551b and miR-25 caused resistance to Dex, however, knockdown of miR-551b and miR-25 significantly enhanced Dex sensitivity in MM. SAE2 knockdown or TAK-981 treatment downregulated the expression of miR-551b and miR-25, leading to induction of miR targets ZFP36, ULK1 and p27, resulting in apoptosis and autophagy. We demonstrated c-Myc as a major transcriptional activator of miR-130b, miR-551b and miR-25 and SUMOylation inhibition downregulates these miRs level by decreasing c-Myc level.ConclusionOur study proves SUMOylation plays a crucial role in Dex resistance in MM and SUMOylation inhibition appears to be an attractive strategy to advance to the clinic for MM patients.