Astaxanthin-mediated Nrf2 activation ameliorates glucocorticoid-induced oxidative stress and mitochondrial dysfunction and impaired bone formation of glucocorticoid-induced osteonecrosis of the femoral head in rats.

BACKGROUND: Osteonecrosis of the femoral head caused by glucocorticoids (GIONFH) is a significant issue resulting from prolonged or excessive clinical glucocorticoid use. Astaxanthin, an orange-red carotenoid present in marine organisms, has been the focus of this study to explore its impact and mechanism on osteoblast apoptosis induced by dexamethasone (Dex) and GIONFH. METHODS: In this experiment, bioinformatic prediction, molecular docking and dynamics simulation, cytotoxicity assay, osteogenic differentiation, qRT-PCR analysis, terminal uridine nickend labeling (TUNEL) assay, determination of intracellular ROS, mitochondrial function assay, immunofluorescence, GIONFH rat model construction, micro-computed tomography (micro-CT) scans were performed. RESULTS: Our research demonstrated that a low dose of astaxanthin was non-toxic to healthy osteoblasts and restored the osteogenic function of Dex-treated osteoblasts by reducing oxidative stress, mitochondrial dysfunction, and apoptosis. Furthermore, astaxanthin rescued the dysfunction in poor bone quality, bone metabolism and angiogenesis of GIONFH rats. The mechanism behind this involves astaxanthin counteracting Dex-induced osteogenic damage by activating the Nrf2 pathway. CONCLUSION: Astaxanthin shields osteoblasts from glucocorticoid-induced oxidative stress and mitochondrial dysfunction via Nrf2 pathway activation, making it a potential therapeutic agent for GIONFH treatment.

[α2-macroglobulin alleviates glucocorticoid-induced avascular necrosis of the femoral head in mice by promoting proliferation, migration and angiogenesis of vascular endothelial cells].

OBJECTIVE: To explore the mechanism underlying the protective effect of α2-macroglobulin (A2M) against glucocorticoid-induced femoral head necrosis. METHODS: In a human umbilical vein endothelial cell (HUVEC) model with injuries induced by gradient concentrations of dexamethasone (DEX; 10-8-10-5 mol/L), the protective effects of A2M at 0.05 and 0.1 mg/mL were assessed by examining the changes in cell viability, migration, and capacity of angiogenesis using CCK-8 assay, Transwell and scratch healing assays and angiogenesis assay. The expressions of CD31 and VEGF-A proteins in the treated cells were detected using Western blotting. In BALB/c mouse models of avascular necrosis of the femoral head induced by intramuscular injections of methylprednisolone, the effects of intervention with A2M on femoral trabecular structure, histopathological characteristics, and CD31 expression were examined with Micro-CT, HE staining and immunohistochemical staining. RESULTS: In cultured HUVECs, DEX treatment significantly reduced cell viability, migration and angiogenic ability in a concentration- and time-dependent manner (P<0.05), and these changes were obviously reversed by treatment with A2M in positive correlation with A2M concentration (P<0.05). DEX significantly reduced the expression of CD31 and VEGF-A proteins in HUVECs, while treatment with A2M restored CD31 and VEGF-A expressions in the cells (P<0.05). The mouse models of femoral head necrosis showed obvious trabecular damages in the femoral head, where a large number of empty lacunae and hypertrophic fat cells could be seen and CD31 expression was significantly decreased (P<0.05). A2M treatment of the mouse models significantly improved trabecular damages, maintained normal bone tissue structures, and increased CD31 expression in the femoral head (P<0.05). CONCLUSION: A2M promotes proliferation, migration, and angiogenesis of DEX-treated HUVECs and alleviates methylprednisolone-induced femoral head necrosis by improving microcirculation damages and maintaining microcirculation stability in the femoral head.

A TH17-intrinsic IL-1ß-STAT5 axis drives steroid resistance in autoimmune neuroinflammation.

Steroid resistance poses a major challenge for the management of autoimmune neuroinflammation. T helper 17 (TH17) cells are widely implicated in the pathology of steroid resistance; however, the underlying mechanisms are unknown. In this study, we identified that interleukin-1 receptor (IL-1R) blockade rendered experimental autoimmune encephalomyelitis (EAE) mice sensitive to dexamethasone (Dex) treatment. Interleukin-1ß (IL-1ß) induced a signal transducer and activator of transcription 5 (STAT5)-mediated steroid-resistant transcriptional program in TH17 cells, which promoted inflammatory cytokine production and suppressed Dex-induced anti-inflammatory genes. TH17-specific deletion of STAT5 ablated the IL-1ß-induced steroid-resistant transcriptional program and rendered EAE mice sensitive to Dex treatment. IL-1ß synergized with Dex to promote the STAT5-dependent expression of CD69 and the development of central nervous system (CNS)-resident CD69+ TH17 cells. Combined IL-1R blockade and Dex treatment ablated CNS-resident TH17 cells, reduced EAE severity, and prevented relapse. CD69+ tissue-resident TH17 cells were also detected in brain lesions of patients with multiple sclerosis. These findings (i) demonstrate that IL-1ß-STAT5 signaling in TH17 cells mediates steroid resistance and (ii) identify a therapeutic strategy for reversing steroid resistance in TH17-mediated CNS autoimmunity.

Investigating the in-vitro bioactivity, biodegradability and drug release behavior of the newly developed PES/HA/WS biocompatible nanocomposites as bone graft substitute.

The nucleation of carbonate-containing apatite on the biomaterials surface is regarded as a significant stage in bone healing process. In this regard, composites contained hydroxyapatite (Ca10(PO4)6(OH)2, HA), wollastonite (CaSiO3, WS) and polyethersulfone (PES) were synthesized via a simple solvent casting technique. The in-vitro bioactivity of the prepared composite films with different weight ratios of HA and WS was studied by placing the samples in the simulated body fluid (SBF) for 21 days. The results indicated that the the surface of composites containing 2 wt% HA and 4 wt% WS was completely covered by a thick bone-like apatite layer, which was characterized by Grazing incidence X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectrometer, field emission electron microscopy and energy dispersive X-ray analyzer (EDX). The degradation study of the samples showed that the concentration of inorganic particles could not influence the degradability of the polymeric matrix, where all samples expressed similar dexamethasone (DEX) release behavior. Moreover, the in-vitro cytotoxicity results indicated the significant cyto-compatibility of all specimens. Therefore, these findings revealed that the prepared composite films composed of PES, HA, WS and DEX could be regarded as promising bioactive candidates with low degradation rate for bone tissue engineering applications.

Therapeutic activity and biodistribution of a nano-sized polymer-dexamethasone conjugate intended for the targeted treatment of rheumatoid arthritis.

Rheumatoid arthritis is a chronic inflammatory autoimmune disease caused by alteration of the immune system. Current therapies have several limitations and the use of nanomedicines represents a promising strategy to overcome them. By employing a mouse model of adjuvant induced arthritis, we aimed to evaluate the biodistribution and therapeutic effects of glucocorticoid dexamethasone conjugated to a nanocarrier based on biocompatible N-(2-hydroxypropyl) methacrylamide copolymers. We observed an increased accumulation of dexamethasone polymer nanomedicines in the arthritic mouse paw using non-invasive fluorescent in vivo imaging and confirmed it by the analysis of tissue homogenates. The dexamethasone conjugate exhibited a dose-dependent healing effect on arthritis and an improved therapeutic outcome compared to free dexamethasone. Particularly, significant reduction of accumulation of RA mediator RANKL was observed. Overall, our data suggest that the conjugation of dexamethasone to a polymer nanocarrier by means of stimuli-sensitive spacer is suitable strategy for improving rheumatoid arthritis therapy.

Nanofiber Hydrogel Drug Delivery System for Prevention of Postsurgical Intestinal Adhesion.

Intestinal adhesion is one of the complications that occurs more frequently after abdominal surgery. Postsurgical intestinal adhesion (PIA) can lead to a series of health problems, including abdominal pain, intestinal obstruction, and female infertility. Currently, hydrogels and nanofibrous films as barriers are often used for preventing PIA formation; however, these kinds of materials have their intrinsic disadvantages. Herein, we developed a dual-structure drug delivery patch consisting of poly lactic-co-glycolic acid (PLGA) nanofibers and a chitosan hydrogel (NHP). PLGA nanofibers loaded with deferoxamine mesylate (DFO) were incorporated into the hydrogel; meanwhile, the hydrogel was loaded with anti-inflammatory drug dexamethasone (DXMS). The rapid degradation of the hydrogel facilitated the release of DXMS at the acute inflammatory stage of the early injury and provided effective anti-inflammatory effects for wound sites. Moreover, PLGA composite nanofibers could provide sustained and stable release of DFO for promoting the peritoneal repair by the angiogenesis effects of DFO. The in vivo results indicated that NHP can effectively prevent PIA formation by restraining inflammation and vascularization, promoting peritoneal repair. Therefore, we believe that our NHP has a great potential application in inhibition of PIA.

Cornflower Extract and Its Active Components Alleviate Dexamethasone-Induced Muscle Wasting by Targeting Cannabinoid Receptors and Modulating Gut Microbiota.

Sarcopenia, a decline in muscle mass and strength, can be triggered by aging or medications like glucocorticoids. This study investigated cornflower (Centaurea cyanus) water extract (CC) as a potential protective agent against DEX-induced muscle wasting in vitro and in vivo. CC and its isolated compounds mitigated oxidative stress, promoted myofiber growth, and boosted ATP production in C2C12 myotubes. Mechanistically, CC reduced protein degradation markers, increased mitochondrial content, and activated protein synthesis signaling. Docking analysis suggested cannabinoid receptors (CB) 1 and 2 as potential targets of CC compounds. Specifically, graveobioside A from CC inhibited CB1 and upregulated CB2, subsequently stimulating protein synthesis and suppressing degradation. In vivo, CC treatment attenuated DEX-induced muscle wasting, as evidenced by enhanced grip strength, exercise performance, and modulation of muscle gene expression related to differentiation, protein turnover, and exercise performance. Moreover, CC enriched gut microbial diversity, and the abundance of Clostridium sensu stricto 1 positively correlated with muscle mass. These findings suggest a multifaceted mode of action for CC: (1) direct modulation of the muscle cannabinoid receptor system favoring anabolic processes and (2) indirect modulation of muscle health through the gut microbiome. Overall, CC presents a promising therapeutic strategy for preventing and treating muscle atrophy.

The subacromial bursa modulates tendon healing after rotator cuff injury in rats.

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Dexamethasone promotes renal fibrosis by upregulating ILT4 expression in myeloid-derived suppressor cells.

Studies have shown that adoptive transfer of myeloid-derived suppressor cells (MDSCs) can alleviate various inflammatory diseases, including glomerulonephritis, but the long-term effects of the transferred MDSCs are still unclear. In addition, although glucocorticoids exert immunosuppressive effects on inflammatory diseases by inducing the expansion of MDSCs, the impact of glucocorticoids on the immunosuppressive function of MDSCs and their molecular mechanisms are unclear. In this study, we found that adoptive transfer of MDSCs to doxorubicin-induced focal segmental glomerulosclerosis (FSGS) mice for eight consecutive weeks led to an increase in serum creatinine and proteinuria and aggravation of renal interstitial fibrosis. Similarly, 8 weeks of high-dose dexamethasone administration exacerbated renal interstitial injury and interstitial fibrosis in doxorubicin-induced mice, manifested as an increase in serum creatinine and proteinuria, collagen deposition and α-SMA expression. On this basis, we found that dexamethasone could enhance MDSC expression and secretion of the fibrosis-related cytokines TGF-ß and IL-10. Mechanistically, we revealed that dexamethasone promotes the expression of immunoglobulin-like transcription factor 4 (ILT4), which enhances the T-cell inhibitory function of MDSCs and promotes the activation of STAT6, thereby strengthening the expression and secretion of TGF-ß and IL-10. Knocking down ILT4 alleviated renal fibrosis caused by adoptive transfer of MDSCs. Therefore, our findings demonstrate that the role and mechanism of dexamethasone mediate the expression and secretion of TGF-ß and IL-10 in MDSCs by promoting the expression of ILT4, thereby leading to renal fibrosis.

Channel Expansion in the Ligand-Binding Domain of the Glucocorticoid Receptor Contributes to the Activity of Highly Potent Glucocorticoid Analogues.

Glucocorticoids (GCs) act through the glucocorticoid receptor (GR) and are commonly used as anti-inflammatory and immunosuppressant medications. Chronic GC use has been linked with unwanted complications such as steroid-induced diabetes mellitus (SIDM), although the mechanisms for these effects are not completely understood. Modification of six GC parent molecules with 2-mercaptobenzothiazole resulted in consistently less promoter activity in transcriptional activation assays using a 3xGRE reporter construct while constantly reducing inflammatory pathway activity. The most selective candidate, DX1, demonstrated a significant reduction (87%) in transactivation compared to commercially available dexamethasone. DX1 also maintained 90% of the anti-inflammatory potential of dexamethasone while simultaneously displaying a reduced toxicity profile. Additionally, two novel and highly potent compounds, DX4 and PN4, were developed and shown to elicit similar mRNA expression at attomolar concentrations that dexamethasone exhibits at nanomolar dosages. To further explain these results, Molecular Dynamic (MD) simulations were performed to examine structural changes in the ligand-binding domain of the glucocorticoid receptor in response to docking with the top ligands. Differing interactions with the transcriptional activation function 2 (AF-2) region of the GR may be responsible for lower transactivation capacity in DX1. DX4 and PN4 lose contact with Arg611 due to a key interaction changing from a stronger hydrophilic to a weaker hydrophobic one, which leads to the formation of an unoccupied channel at the location of the deacylcortivazol (DAC)-expanded binding pocket. These findings provide insights into the structure-function relationships important for regulating anti-inflammatory activity, which has implications for clinical utility.

Riluzole Reverses a Number of Undesirable Effects of Dexamethasone in Glioblastoma Cells.

BACKGROUND/AIM: Glioblastoma multiforme (GBM)-induced oedema is a major cause of morbidity and mortality among patients with GBM. Dexamethasone (Dex) is the most common corticosteroid used pre-operatively to control cerebral oedema in patients with GBM. Dex is associated with many side effects, and shorter overall survival and progression-free survival of patients with GBM. These negative effects of Dex highlight the need for combinational therapy. Riluzole (Ril), a drug used to treat amyotrophic lateral sclerosis (ALS), is thought to have potential as a treatment for various cancers, with clinical trials underway. Here, we investigated whether Ril could reverse some of the undesirable effects of Dex. MATERIALS AND METHODS: The effect of Dex, Ril, and Ril-Dex treatment on cell migration was monitored using the xCELLigence system. Cell viability assays were performed using 3-(4, 5-dimethylthiazol)-2, 5-diphenyltetrazolium bromide (MTT). The expression of genes involved in migration, glucose metabolism, and stemness was examined using real-time polymerase chain reaction (PCR). RESULTS: Pre-treating GBM cells with Ril reduced Dex-induced cell migration and altered Dex-induced effects on cell invasion, stem cell, and glucose metabolism markers. Furthermore, Ril remained effective in killing GBM cells in combination with Dex. CONCLUSION: Ril, which acts as an anti-tumorigenic drug, mediates some of the negative effects of Dex; therefore, it could be a potential drug to manage the side effects of Dex therapy in GBM.

Beef peptides mitigate skeletal muscle atrophy in C2C12 myotubes through protein degradation, protein synthesis, and the oxidative stress pathway.

This study aimed to investigate the potential of beef peptides (BPs) in mitigating muscle atrophy induced by dexamethasone (DEX) with underlying three mechanisms in vitro (protein degradation, protein synthesis, and the oxidative stress pathway). Finally, the anti-atrophic effect of BPs was enhanced through purification and isolation. BPs were generated using beef loin hydrolyzed with alcalase/ProteAX/trypsin, each at a concentration of 0.67%, followed by ultrafiltration through a 3 kDa cut-off. BPs (10-100 µg mL-1) dose-dependently counteracted the DEX-induced reductions in myotube diameters, differentiation, fusion, and maturation indices (p < 0.05). Additionally, BPs significantly reduced FoxO1 protein dephosphorylation, thereby suppressing muscle-specific E3 ubiquitin ligases such as muscle RING-finger containing protein-1 and muscle atrophy F-box protein in C2C12 myotubes at concentrations exceeding 25 µg mL-1 (p < 0.05). BPs also enhanced the phosphorylation of protein synthesis markers, including mTOR, 4E-BP1, and p70S6K1, in a dose-dependent manner (p < 0.05) and increased the mRNA expression of antioxidant enzymes. Fractionated peptides derived from BPs, through size exclusion and polarity-based fractionation, also demonstrated enhanced anti-atrophic effects compared to BPs. These peptides downregulated the mRNA expression of primary muscle atrophy markers while upregulated that of antioxidant enzymes. Specifically, peptides GAGAAGAPAGGA (MW 924.5) and AFRSSTKK (MW 826.4) were identified from fractionated peptides of BPs. These findings suggest that BPs, specifically the peptide fractions GAGAAGAPAGGA and AFRSSTKK, could be a potential strategy to mitigate glucocorticoid-induced skeletal muscle atrophy by reducing the E3 ubiquitin ligase activity.

[A sericin hydrogel scaffold for sustained dexamethasone release modulates macrophage polarization to promote mandibular bone defect repair in rats].

OBJECTIVE: To evaluate the efficacy of a modified sericin hydrogel scaffold loaded with dexamethasone (SMH-CD/DEX) scaffold for promoting bone defect healing by stimulating anti-inflammatory macrophage polarization. METHODS: The light-curable SMH-CD/DEX scaffold was prepared using dexamethasone-loaded NH2-ß-cyclodextrin (NH2-ß-CD) and sericin hydrogel and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), biocompatibility assessment and drug release test. THP-1 macrophages incubated with the scaffold were examined for protein expressions of iNOS and Arg-1, mRNA expressions of IL-6, Il-10, Arg-1 and iNOS, and surface markers CD86 and CD206 using Western blotting, RT-qPCR, and flow cytometry. In a co-culture system of human periodontal ligament stem cells (HPDLSCs) and THP-1 macrophages, the osteogenic ability of the stem cells incubated with the scaffold was evaluated by detecting protein expressions of COL1A1 and Runx2 and expressions of ALP, Runx2, OCN and BMP2 mRNA, ALP staining, and alizarin red staining. In a rat model of mandibular bone defect, the osteogenic effect of the scaffold was assessed by observing bone regeneration using micro-CT and histopathological staining. RESULTS: In THP-1 macrophages, incubation with SMH-CD/DEX scaffold significantly enhanced protein expressions of Arg-1 and mRNA expressions of IL-10 and Arg-1 and lowered iNOS protein expression and IL-6 and iNOS mRNA expressions. In the co-culture system, SMH-CD/DEX effectively increased the protein expressions of COL1A1 and Runx2 and mRNA expressions of ALP and BMP2 in HPDLSCs and promoted their osteogenic differentiation. In the rat models, implantation of SMH-CD/DEX scaffold significantly promoted bone repair and bone regeneration in the bone defect. CONCLUSION: The SMH-CD/DEX scaffold capable of sustained dexamethasone release promotes osteogenic differentiation of stem cells and bone defect repair in rats by regulating M2 polarization.

Liraglutide and Naringenin relieve depressive symptoms in mice by enhancing Neurogenesis and reducing inflammation.

Depression is a debilitating mental disease that negatively impacts individuals' lives and society. Novel hypotheses have been recently proposed to improve our understanding of depression pathogenesis. Impaired neuroplasticity and upregulated neuro-inflammation add-on to the disturbance in monoamine neurotransmitters and therefore require novel anti-depressants to target them simultaneously. Recent reports demonstrate the antidepressant effect of the anti-diabetic drug liraglutide. Similarly, the natural flavonoid naringenin has shown both anti-diabetic and anti-depressant effects. However, the neuro-pharmacological mechanisms underlying their actions remain understudied. The study aims to evaluate the antidepressant effects and neuroprotective mechanisms of liraglutide, naringenin or a combination of both. Depression was induced in mice by administering dexamethasone (32 mcg/kg) for seven consecutive days. Liraglutide (200 mcg/kg), naringenin (50 mg/kg) and a combination of both were administered either simultaneously or after induction of depression for twenty-eight days. Behavioral and molecular assays were used to assess the progression of depressive symptoms and biomarkers. Liraglutide and naringenin alone or in combination alleviated the depressive behavior in mice, manifested by decrease in anxiety, anhedonia, and despair. Mechanistically, liraglutide and naringenin improved neurogenesis, decreased neuroinflammation and comparably restored the monoamines levels to that of the reference drug escitalopram. The drugs protected mice from developing depression when given simultaneously with dexamethasone. Collectively, the results highlight the usability of liraglutide and naringenin in the treatment of depression in mice and emphasize the different pathways that contribute to the pathogenesis of depression.

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

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.

LSD1 inhibition circumvents glucocorticoid-induced muscle wasting of male mice.

Synthetic glucocorticoids (GC), such as dexamethasone, are extensively used to treat chronic inflammation and autoimmune disorders. However, long-term treatments are limited by various side effects, including muscle atrophy. GC activities are mediated by the glucocorticoid receptor (GR), that regulates target gene expression in various tissues in association with cell-specific co-regulators. Here we show that GR and the lysine-specific demethylase 1 (LSD1) interact in myofibers of male mice, and that LSD1 connects GR-bound enhancers with NRF1-associated promoters to stimulate target gene expression. In addition, we unravel that LSD1 demethylase activity is required for triggering starvation- and dexamethasone-induced skeletal muscle proteolysis in collaboration with GR. Importantly, inhibition of LSD1 circumvents muscle wasting induced by pharmacological levels of dexamethasone, without affecting their anti-inflammatory activities. Thus, our findings provide mechanistic insights into the muscle-specific GC activities, and highlight the therapeutic potential of targeting GR co-regulators to limit corticotherapy-induced side effects.

A New Indole Derivative, LWX-473, Overcomes Glucocorticoid Resistance in Jurkat Cells by Activating Mediators of Apoptosis.

BACKGROUND: Glucocorticoids (GCs) are commonly used as the primary chemotherapy for lymphoid malignancies, including acute lymphoblastic leukemia (ALL). However, the development of GC resistance limits their prolonged use. METHODS: In this study, we investigated the potential of a newly synthesized indole derivative called LWX-473, in combination with the classic GC Dexamethasone (DEX), to enhance the responsiveness of Jurkat cells to GC treatment. RESULTS: Our findings demonstrate that LWX-473 alone or in combination with DEX significantly improves GC-induced cell apoptosis and arrests the cell cycle in the G1 phase. Notably, the combination of LWX-473 and DEX exhibits superior efficacy in killing Jurkat cells compared to LWX-473 alone. Importantly, this compound demonstrates reduced toxicity towards normal cells. CONCLUSIONS: Our study reveals that LWX-473 has the ability to restore the sensitivity of Jurkat cells to DEX by modulating the mitochondrial membrane potential, activating the expression of DEX-liganded glucocorticoid receptor (GR), and inhibiting key molecules in the JAK/STAT signaling pathway. These findings suggest that LWX-473 could be a potential therapeutic agent for overcoming GC resistance in lymphoid malignancies.

Nonclinical Investigation of Cytokine Mitigation Strategies for T-cell-Engaging Bispecifics in the Cynomolgus Macaque.

SUMMARY: T-cell-directed cancer therapies such as T-cell-engaging bispecifics (TCBs) are commonly associated with cytokine release syndrome and associated clinical signs that can limit their tolerability and therapeutic benefit. Strategies for reducing cytokine release are therefore needed. Here, we report on studies performed in cynomolgus monkeys to test different approaches for mitigating cytokine release with TCBs. A "priming dose" as well as subcutaneous dosing reduced cytokine release compared with intravenous dosing but did not affect the intended T-cell response to the bispecific. As another strategy, cytokines or cytokine responses were blocked with an anti-IL-6 antibody, dexamethasone, or a JAK1/TYK2-selective inhibitor, and the effects on toxicity as well as T-cell responses to a TCB were evaluated. The JAK1/TYK2 inhibitor and dexamethasone prevented CRS-associated clinical signs on the day of TCB administration, but the anti-IL-6 had little effect. All interventions allowed for functional T-cell responses and expected damage to target-bearing tissues, but the JAK1/TYK2 inhibitor prevented the upregulation of activation markers on T cells, suggesting the potential for suppression of T-cell responses. Our results suggest that short-term prophylactic dexamethasone treatment may be an effective option for blocking cytokine responses without affecting desired T-cell responses to TCBs.

Taurine activates the AKT-mTOR axis to restore muscle mass and contractile strength in human 3D in vitro models of steroid myopathy.

Steroid myopathy is a clinically challenging condition exacerbated by prolonged corticosteroid use or adrenal tumors. In this study, we engineered a functional three-dimensional (3D) in vitro skeletal muscle model to investigate steroid myopathy. By subjecting our bioengineered muscle tissues to dexamethasone treatment, we reproduced the molecular and functional aspects of this disease. Dexamethasone caused a substantial reduction in muscle force, myotube diameter and induced fatigue. We observed nuclear translocation of the glucocorticoid receptor (GCR) and activation of the ubiquitin-proteasome system within our model, suggesting their coordinated role in muscle atrophy. We then examined the therapeutic potential of taurine in our 3D model for steroid myopathy. Our findings revealed an upregulation of phosphorylated AKT by taurine, effectively countering the hyperactivation of the ubiquitin-proteasomal pathway. Importantly, we demonstrate that discontinuing corticosteroid treatment was insufficient to restore muscle mass and function. Taurine treatment, when administered concurrently with corticosteroids, notably enhanced contractile strength and protein turnover by upregulating the AKT-mTOR axis. Our model not only identifies a promising therapeutic target, but also suggests combinatorial treatment that may benefit individuals undergoing corticosteroid treatment or those diagnosed with adrenal tumors.

Assessing the impact of COVID-19 era drug combinations on hepatic functionality: A thorough investigation in adult Danio rerio.

Current and thorough information on the ecotoxicological consequences of pharmaceuticals is accessible globally. However, there remains a substantial gap in knowledge concerning the potentially toxic effects of COVID-19 used drugs, individually and combined, on aquatic organisms. Given the factors above, our investigation assumes pivotal importance in elucidating whether or not paracetamol, dexamethasone, metformin, and their tertiary mixtures might prompt histological impairment, oxidative stress, and apoptosis in the liver of zebrafish. The findings indicated that all treatments, except paracetamol, augmented the antioxidant activity of superoxide dismutase (SOD) and catalase (CAD), along with elevating the levels of oxidative biomarkers such as lipid peroxidation (LPX), hydroperoxides (HPC), and protein carbonyl content (PCC). Paracetamol prompted a reduction in the activities SOD and CAT and exhibited the most pronounced toxic response when compared to the other treatments. The gene expression patterns paralleled those of oxidative stress, with all treatments demonstrating overexpression of bax, bcl2, and p53. The above suggested a probable apoptotic response in the liver of the fish. Nevertheless, our histological examinations revealed that none of the treatments induced an apoptotic or inflammatory response in the hepatocytes. Instead, the observed tissue alterations encompassed leukocyte infiltration, sinusoidal dilatation, pyknosis, fatty degeneration, diffuse congestion, and vacuolization. In summary, the hepatic toxicity elicited by COVID-19 drugs in zebrafish was less pronounced than anticipated. This attenuation could be attributed to metformin's antioxidant and hormetic effects.