Temporal Control of the WNT Signaling Pathway During Cardiac Differentiation Impacts Upon the Maturation State of Human Pluripotent Stem Cell Derived Cardiomyocytes.

Inefficient differentiation and insufficient maturation are barriers to the application of human pluripotent stem cell (hPSC)-derived cardiomyocytes (CMs) for research and therapy. Great strides have been made to the former, and multiple groups have reported cardiac differentiation protocol that can generate hPSC-CMs at high efficiency. Although many such protocols are based on the modulation of the WNT signaling pathway, they differ in their timing and in the WNT inhibitors used. Little is currently known about whether and how conditions of differentiation affect cardiac maturation. Here we adapted multiple cardiac differentiation protocols to improve cost-effectiveness and consistency, and compared the properties of the hPSC-CMs generated. Our results showed that the schedule of differentiation, but not the choice of WNT inhibitors, was a critical determinant not only of differentiation efficiency, which was expected, but also CM maturation. Among cultures with comparable purity, hPSC-CMs generated with different differentiation schedules vary in the expression of genes which are important for developmental maturation, and in their structural, metabolic, calcium transient and proliferative properties. In summary, we demonstrated that simple changes in the schedule of cardiac differentiation could promote maturation. To this end, we have optimized a cardiac differentiation protocol that can simultaneously achieve high differentiation efficiency and enhanced developmental maturation. Our findings would advance the production of hPSC-CMs for research and therapy.

Remdesivir induces persistent mitochondrial and structural damage in human induced pluripotent stem cell-derived cardiomyocytes.

AIMS: Remdesivir is a prodrug of an adenosine triphosphate analogue and is currently the only drug formally approved for the treatment of hospitalized coronavirus disease of 2019 (COVID-19) patients. Nucleoside/nucleotide analogues have been shown to induce mitochondrial damage and cardiotoxicity, and this may be exacerbated by hypoxia, which frequently occurs in severe COVID-19 patients. Although there have been few reports of adverse cardiovascular events associated with remdesivir, clinical data are limited. Here, we investigated whether remdesivir induced cardiotoxicity using an in vitro human cardiac model. METHODS AND RESULTS: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were exposed to remdesivir under normoxic and hypoxic conditions to simulate mild and severe COVID-19, respectively. Remdesivir induced mitochondrial fragmentation, reduced redox potential, and suppressed mitochondrial respiration at levels below the estimated plasma concentration under both normoxic and hypoxic conditions. Non-mitochondrial damage such as electrophysiological alterations and sarcomere disarray were also observed. Importantly, some of these changes persisted after the cessation of treatment, culminating in increased cell death. Mechanistically, we found that inhibition of DRP1, a regulator of mitochondrial fission, ameliorated the cardiotoxic effects of remdesivir, showing that remdesivir-induced cardiotoxicity was preventable and excessive mitochondrial fission might contribute to this phenotype. CONCLUSIONS: Using an in vitro model, we demonstrated that remdesivir can induce cardiotoxicity in hiPSC-CMs at clinically relevant concentrations. These results reveal previously unknown potential side-effects of remdesivir and highlight the importance of further investigations with in vivo animal models and active clinical monitoring to prevent lasting cardiac damage to patients.

Baoyuan Capsule promotes neurogenesis and neurological functional recovery through improving mitochondrial function and modulating PI3K/Akt signaling pathway.

BACKGROUND: Bao Yuan Capsule (BYC) is a patented Chinese medicinal formula for health promotion but its application for ischemic stroke remains unknown. In this study, we proposed the hypothesis that BYC could promote neurogenesis and neurological functional recovery through promoting mitochondrial function and activating PI3K/Akt signaling pathway. METHODS: We firstly performed chemical identification studies by using QIT-TOF-MS technology. Then, we investigated the effects of BYC (1 g/kg, 2 g/kg, 4 g/kg per day) on improving the recovery of the neurological functions in transient middle cerebral artery occlusion (MCAO) ischemic mice. RESULTS: We tentatively characterized 36 compounds from the BYC extractions. At dosage of 4 g/kg, BYC effectively improved locomotor ability, attenuated anxiety-like behaviors, and enhanced the exploring behaviors, learning and memory capability in the transient MCAO ischemic mice. BYC treatment promoted neural stem cell differentiations in the subventricular zone (SVZ) and subgranular zone (SGZ) of the MCAO mice. BYC also up-regulated the expression of Aconitase 2 (ACO2), Succinate dehydrogenase complex, subunit A (SDHA), phosphorylation of AMP-activated protein kinase (p-AMPK), protein kinase B (p-Akt) and glycogen synthase kinase 3ß (p-GSK3ß) in the hippocampus of the MCAO mice. BYC (200 µg/ml) significantly improved the mitochondrial functions in cultured mouse multipotent neural stem like C17.2 cells. BYC treatment also promoted neuronal differentiations in the C17.2 cells under oxygen-glucose deprivation (OGD) condition. The neurogenetic effects were abolished by co-treatments of ATP synthesis inhibitor oligomycin and PI3K/Akt inhibitor wortmannin. Moreover, Akt phosphorylation was dramatically reduced by oligomycin. CONCLUSION: BYC could promote neurogenesis and neurological functional recovery in post ischemic brains by regulating the mitochondrial functions and Akt signaling pathway.

Generation of genomic-integration-free human induced pluripotent stem cells and the derived cardiomyocytes of X-linked dilated cardiomyopathy from DMD gene mutation.

We derived an integration-free induced pluripotent stem cell (iPSC) line from the peripheral blood mononuclear cells (PBMCs) of a 23-year-old male patient. This patient carries a 5' splice site point mutation in intron 1 (c.31+1G>A) of the dystrophin gene, a mutation associated with X-linked dilated cardiomyopathy (XLDCM). Sendai virus was used to reprogram the PBMCs and deliver OCT3/4, SOX2, c-MYC, and KLF4 factors. The iPSC line (HKUi002-A) generated preserved the mutation, expressed common pluripotency markers, differentiated into three germ layers in vivo, and exhibited a normal karyotype. Further differentiation into cardiomyocytes enables the study of the disease mechanisms of XLDCM.

Combination of matrix solid phase dispersion and response surface evaluation for simultaneous detections of multiple bioactive constituents of traditional Chinese medicine formula: Using Baoyuan Capsule as an example.

Traditional Chinese Medicine (TCM) formulae contain abundant chemical ingredients, leading to the development of high quality TCM productions be difficult. With different pharmacokinetic and pharmacodynamic parameters of the chemical ingredients in a TCM formula, it is desirable to simultaneously identify multiple ingredients for accurate quality control. In the present study, we introduce a novel strategy for TCM formula quality assessment by using the combined methods of the extraction condition optimization, quantitative analyzation, and response surface evaluation. We used Bao-Yuan Capsule (BYC), a patented TCM production, as a model system for quality assessment. We applied matrix solid phase dispersion (MSPD) as a rapid and efficient method to prepare sample extraction. Q-Trap-MS related accurate methods were applied to simultaneously analyze 13 bioactive constituents as bioactive markers in the BYC. Those methods revealed a high sensitivity to detect the target compounds at the concentrations ranging from 0.12 to 0.95 ng/mL for flavonoids and ginsenosides whose recoveries were ranged from 91.93%-105.84%. We employed the response surface methodology to optimize the extraction conditions including dispersant/sample ratio, solvent concentration, and elution volume based on the content of ginsenosides as the test samples. The results showed the high extraction efficiency of ginsenosides with dispersant/sample ratio at 3/4, methanol concentration at 85 %, and elution volume at 15 mL. Taken together, we conclude that the combination strategy of MSPD and response surface evaluation for simultaneous detections of multiple bioactive constituents could be a powerful and efficient method for performing accurately quality control of complex TCM production preparations.

Acteoside ameliorates experimental autoimmune encephalomyelitis through inhibiting peroxynitrite-mediated mitophagy activation.

Multiple sclerosis (MS) is an inflammatory disease in central nervous system (CNS) with limited therapeutic drugs. In the present study, we explored the anti-inflammatory/neuroprotective properties of Acteoside (AC), an active compound from medicinal herb Radix Rehmanniae (RR), and neuroprotective effects of AC on MS pathology by using an experimental autoimmune encephalomyelitis (EAE) model. We tested the hypothesis that AC could alleviate EAE pathogenesis through inhibiting inflammation and ONOO--mediated mitophagy activation in vivo and in vitro. The results showed that AC treatment effectively ameliorated neurological deficit score and postponed disease onset in the EAE mice. AC treatment inhibited inflammation/demyelination, alleviated peripheral activation and CNS infiltration of encephalitogenic CD4+ T cells and CD11b+ activated microglia/macrophages in the spinal cord of EAE mice. Meanwhile, AC treatment reduced ONOO- production, down-regulated the expression of iNOS and NADPH oxidases, and inhibited neuronal apoptotic cell death and mitochondrial damage in the spinal cords of the EAE mice. Furthermore, AC treatment decreased the ratio of LC3-II to LC3-I in mitochondrial fraction, and inhibited the translocation of Drp1 to the mitochondria. In vitro studies further proved that AC possessed strong ONOO- scavenging capability and protected the neuronal cells from nitrative cytotoxicity via suppressing ONOO--mediated excessive mitophagy. Taken together, Acteoside could be a potential therapeutic agent for multiple sclerosis treatment. The suppression of ONOO--induced excessive mitophagy activation could be one of the critical mechanisms contributing to its anti-inflammatory and anti-demyelinating properties.

Baicalin Modulates APPL2/Glucocorticoid Receptor Signaling Cascade, Promotes Neurogenesis, and Attenuates Emotional and Olfactory Dysfunctions in Chronic Corticosterone-Induced Depression.

Olfactory dysfunction is often accompanied with anxiety- and depressive-like behaviors in depressive patients. Impaired neurogenesis in hippocampus and subventricular zone (SVZ)-olfactory bulb (OB) contribute to anxiety- and depressive-like behaviors and olfactory dysfunctions. However, the underlying mechanisms of olfactory dysfunction remain unclear. Our previous study indicates that adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 2 (APPL2), could affect the activity and sensitivity of glucocorticoid receptor (GR) and mediate impaired hippocampal neurogenesis, which contribute the development of depression. In the present study, we further identified the roles of APPL2 in olfactory functions. APPL2 Tg mice displayed higher GR activity and less capacity of neurogenesis at olfactory system with less olfactory sensitivity than WT mice, indicating that APPL2 could be a potential therapeutic target for depression and olfactory deficits. We then studied the effects of baicalin, a medicinal herbal compound, on modulating APPL2/GR signaling pathway for promoting neurogenesis and antidepressant as well as improving olfactory functions. Baicalin treatment inhibited APPL2/GR signaling pathway and improved neurogenesis at SVZ, OB, and hippocampus in APPL2 Tg mice and chronic corticosterone-induced depression mouse model. Behavioral tests revealed that baicalin attenuated depressive- and anxiety-like behaviors and improve olfactory functions in the chronic depression mouse model and APPL2 Tg mice. Taken together, APPL2 could be a novel therapeutic target for improving depressant-related olfactory dysfunctions and baicalin could inhibit APPL2-mediated GR hyperactivity and promote adult neurogenesis, subsequently releasing depressive and anxiety symptoms and improving olfactory functions for antidepressant therapy.

Caveolin-1 Is Critical for Lymphocyte Trafficking into Central Nervous System during Experimental Autoimmune Encephalomyelitis.

UNLABELLED: Multiple sclerosis (MS) is a progressive autoimmune disease of the CNS with its underlying mechanisms not fully understood. In the present study, we tested the hypothesis that caveolin-1, a major membrane scaffolding protein, plays a critical role in the pathogenesis of experimental autoimmune encephalomyelitis, a laboratory murine model of MS. We found increased expression of caveolin-1 in serum and spinal cord tissues in association with disease incidence and severity in wild-type mice with active encephalomyelitis. After immunization, Cav-1 knock-out mice showed remarkable disease resistance with decreased incidence and clinical symptoms. Furthermore, Cav-1 knock-out mice had alleviated encephalitogenic T cells trafficking into the CNS with decreased expressions of adhesion molecules ICAM-1 and VCAM-1 within the lesions. In agreement with in vivo studies, in vitro knockdown of caveolin-1 compromised the upregulation of ICAM-1 in endothelial cells, leading to the amelioration of the transendothelial migration of pathogenic TH1 and TH17 cells. Together, those results indicate that caveolin-1 serves as an active modulator of CNS-directed lymphocyte trafficking and could be a therapeutic target for neuroinflammatory diseases, such as multiple sclerosis. SIGNIFICANCE STATEMENT: The hallmark feature of neuroinflammatory diseases is the massive infiltrations of encephalitogenic leukocytes into the CNS parenchyma, a process that remains largely unclear. Our study demonstrates the critical contribution of caveolin-1 to encephalomyelitis pathogenesis and CNS-directed lymphocyte trafficking by modulation of adhesion molecules ICAM-1 and VCAM-1, highlighting the pathological involvement of caveolin-1 in neuroinflammatory diseases.

Epac Activation Regulates Human Mesenchymal Stem Cells Migration and Adhesion.

How to enhance the homing of human mesenchymal stem cells (hMSCs) to the target tissues remains a clinical challenge nowadays. To overcome this barrier, the mechanism responsible for the hMSCs migration and engraftment has to be defined. Currently, the exact mechanism involved in migration and adhesion of hMSCs remains unknown. Exchange protein directly activated by cAMP (Epac), a novel protein discovered in cAMP signaling pathway, may have a potential role in regulating cells adhesion and migration by triggering the downstream Rap family signaling cascades. However, the exact role of Epac in cells homing is elusive. Our study evaluated the role of Epac in the homing of hMSCs. We confirmed that hMSCs expressed functional Epac and its activation enhanced the migration and adhesion of hMSCs significantly. The Epac activation was further found to be contributed directly to the chemotactic responses induced by stromal cell derived factor-1 (SDF-1) which is a known chemokine in regulating hMSCs homing. These findings suggested Epac is connected to the SDF-1 signaling cascades. In conclusion, our study revealed that Epac plays a role in hMSCs homing by promoting adhesion and migration. Appropriate manipulation of Epac may enhance the homing of hMSCs and facilitate their future clinical applications.

Pros and cons of current approaches for detecting peroxynitrite and their applications.

Peroxynitrite, a representative of reactive nitrogen species, plays important roles in the physiological and pathological processes of many oxidative stress-related diseases. It is generated from the reaction of nitric oxide (NO) and superoxide (O2·-) and is far more active than its precursors. Peroxynitrite can be further decomposed into other cytotoxic reactive species. Peroxynitrite and its derivatives can interact with various biomolecules such as DNA and proteins. Due to its high reactivity and short lifetime, accurate detection of peroxynitrite in biological systems is a challenge task. In the last decade, huge efforts have been made to develop reliable techniques to assess the generation of peroxynitrite in various cellular and animal experiments. There are three major approaches for peroxynitrite detection, including electrochemical sensors, detection of nitrotyrosine formation, and fluorescent probes. Particularly, progress has been made in developing novel fluorescent probes to detect peroxynitrite with relatively high sensitivity and specificity. Herein, we review the recent progress made in peroxynitrite detection methods and discuss the advantages and disadvantages of these methods. The development of these techniques will offer new opportunities for understanding the roles of peroxynitrite in the oxidative stress-related physiological and pathological conditions and provide platforms for drug discovery targeting peroxynitrite and other free radicals for therapeutic purposes.

Brazilian green propolis and its constituent, Artepillin C inhibits allogeneic activated human CD4 T cells expansion and activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Propolis has long been used as a popular folk medicine by various ethnic groups due to its wide spectrum of alleged biological and pharmaceutical properties including anti-microbial, anti-cancer and anti-inflammatory functions. All these can be linked to the modulation of immune function. Therefore, it will be relevant for us to find out whether there is any novel compound that can account for such action and the mechanism involved. AIM OF THE STUDY: We investigated the immune modulating effect of Brazilian green propolis (PBrazil) and its constituent Artepillin C (Art-C) by using mixed leukocytes reaction. MATERIALS AND METHODS: The cytotoxic effect of Art-C on non-tumorigenic human liver cell line miHA and non-tumorigenic human kidney cell line HK-2 as well as human peripheral blood mononuclear cells (PBMCs) were measured by XTT cell proliferation assay. The effect of PBrazil and Art-C on T cell proliferation and activation were determined by using carboxyfluorescein succinimidyl ester (CFSE) and by CD25 expression, respectively. Cytokines including tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ), interleukins such as IL-2, IL-17 were measured by intracellular cytokine staining and IL-10 was measured by ELISA. The effect of PBrazil and Art-C on regulatory T cells (Treg) induction was determined by the Foxp3 expression. The apoptotic effect of these compounds on CFSE labeled alloreactive T cells was measured by using Annexin V. RESULTS: Using mixed leukocytes reaction we demonstrated for the first time that both Art-C and PBrazil significantly inhibited the alloreactive CD4 T cell proliferation, activation, and suppressed the expressions of IL-2, IFN-γ and IL-17 in these alloreactive CD4 T cells. The inhibitions of Art-C and PBrazil on CD4 T cells were not due to direct cytotoxic effect on PBMC or inducing regulatory T cells differentiation. Both Art-C and PBrazil were found to selectively induce apoptosis in proliferating T cells. The anti-proliferative effect of Art-C and PBrazil were reversible and were also applied to the activated T cells. CONCLUSIONS: In conclusion, our results indicated that Art-C and PBrazil can suppress alloreactive CD4 T cell responses in vitro, suggesting that Art-C could be used as a potential immunosuppressant, either solely or as adjunct agent in treating graft versus host disease.

Mesenchymal stromal cells may enhance metastasis of neuroblastoma via SDF-1/CXCR4 and SDF-1/CXCR7 signaling.

Bone marrow metastasis is frequently observed in patients with high-risk neuroblastoma. Mesenchymal stromal cells (MSCs) in bone marrow may enhance tumor metastasis through secreting stromal cell-derived factor-1 (SDF-1). Here we investigated neuroblastoma cell behaviors under the influence of MSCs and explored the function of SDF-1 signaling during metastasis. Neuroblastoma expressed both of the SDF-1 receptors CXCR4 and CXCR7. shRNA knockdown showed that these receptors were responsible for the migration of neuroblastoma towards MSCs. CXCR4 also supported neuroblastoma invasion. These effects could be effectively blocked by AMD3100, a potent SDF-1 antagonist. Our study suggests that MSCs are important for neuroblastoma metastasis via the secretion of SDF-1 and that such effect can be inhibited by AMD3100 or shRNA knockdown.

Polysaccharides from the root of Angelica sinensis promotes hematopoiesis and thrombopoiesis through the PI3K/AKT pathway.

BACKGROUND: Dozens of Traditional Chinese Medicine (TCM) formulas have been used for promotion of "blood production" for centuries, and we are interested in developing novel thrombopoietic medicines from these TCMs. Our previous studies have demonstrated the hematopoietic effects of DangGui BuXue Tong (DBT), a formula composed of Radix Angelicae Sinensis and Radix Astragali in animal and cellular models. As a step further to identify and characterize the active chemical components of DBT, we tested the hematopoietic and particularly, thrombopoietic effects of polysaccharide-enriched fractions from the root of Radix Angelicae Sinensis (APS) in this study. METHODS: A myelosuppression mouse model was treated with APS (10 mg/kg/day). Peripheral blood cells from APS, thrombopoietin and vehicle-treated samples were then counted at different time-points. Using the colony-forming unit (CFU) assays, we determined the effects of APS on the proliferation and differentiation of hematopoietic stem/progenitor cells and megakaryocytic lineages. Using a megakaryocytic cell line M-07e as model, we analyzed the cellular apoptosis progression with and without APS treatment by Annexin V, Mitochondrial Membrane Potential and Caspase 3 assays. Last, the anti-apoptotic effect of APS on cells treated with Ly294002, a Phosphatidylinositol 3-Kinse inhibitor (PI3K) was also tested. RESULTS: In animal models, APS significantly enhanced not only the recovery of platelets, other blood cells and their progenitor cells, but also the formation of Colony Forming Unit (CFU). In M-07e cells, we observed the anti-apoptotic effect of APS. Treatment by Ly294002 alone increased the percentage of cells undergoing apoptosis. However, addition of APS to Ly294002-treated cells significantly reduced the percentage of cells undergoing apoptosis. CONCLUSIONS: APS promotes hematopoiesis and thrombopoiesis in the mouse model. This effect likely resulted from the anti-apoptosis activity of APS and is likely to involve the PI3K/AKT pathway.

Platelet-derived growth factor enhances platelet recovery in a murine model of radiation-induced thrombocytopenia and reduces apoptosis in megakaryocytes via its receptors and the PI3-k/Akt pathway.

BACKGROUND: Platelet-derived growth factor is involved in the regulation of hematopoiesis. Imatinib mesylate, a platelet-derived growth factor receptor inhibitor, induces thrombocytopenia in a significant proportion of patients with chronic myeloid leukemia. Although our previous studies showed that platelet-derived growth factor enhances megakaryocytopoiesis in vitro, the in vivo effect of platelet-derived growth factor in a model of radiation-induced thrombocytopenia has not been reported. DESIGN AND METHODS: In this study, we investigated the effect of platelet-derived growth factor on hematopoietic stem/progenitor cells and platelet production using an irradiated-mouse model. We also explored the potential molecular mechanisms of platelet-derived growth factor on thrombopoiesis in M-07e cells. RESULTS: Platelet-derived growth factor, like thrombopoietin, significantly promoted the recovery of platelets and the formation of bone marrow colony-forming unit-megakaryocyte in irradiated mice. Histology confirmed the protective effect of platelet-derived growth factor, as shown by an increased number of hematopoietic stem/progenitor cells and a reduction of apoptosis. In a megakaryocytic apoptotic model, platelet-derived growth factor had a similar anti-apoptotic effect as thrombopoietin on megakaryocytes. We also demonstrated that platelet-derived growth factor activated the PI3-k/Akt signaling pathway, while addition of imatinib mesylate reduced p-Akt expression. CONCLUSIONS: Our findings show that platelet-derived growth factor enhances platelet recovery in mice with radiation-induced thrombocytopenia. This radioprotective effect is likely to be mediated via platelet-derived growth factor receptors with subsequent activation of the PI3-k/Akt pathway. We also provide a possible explanation that blockage of platelet-derived growth factor receptors may reduce thrombopoiesis and play a role in imatinib mesylate-induced thrombocytopenia.

An herbal decoction of Radix astragali and Radix angelicae sinensis promotes hematopoiesis and thrombopoiesis.

ETHNOPHARMACOLOGICAL RELEVANCE: A decoction containing Radix angelicae sinensis and Radix astragali (Danggui Buxue Tang, DBT) has been used to raise the "Qi" and nourish the "Blood". However, its effects on haematopoiesis and particularly thrombopoiesis have not been studied. AIMS: This study aims to examine the effects of DBT on hematopoiesis and thrombopoiesis. MATERIALS AND METHODS: A myelosuppression mouse model was treated with DBT (10mg/kg/day). Peripheral blood cells from DBT and thrombopoietin-treated samples were counted on days 0, 7, 14 and 21. Then CFU assays were used to determine the effects of DBT on the megakaryocytic progenitor cells and other lineages. Last, analyses of annexin V, caspase-3, and mitochondrial membrane potential were conducted in megakaryocytic cell line M-07e. RESULTS: Morphological examination showed that DBT treatment significantly increased the recovery of the megakaryocytic series. DBT significantly enhanced the platelet recovery and CFU-MK formation in vivo. DBT significantly promoted CFU-MK and CFU-F formation. Last, we observed the antiapoptotic effects of DBT on M-07e cells. CONCLUSION: DBT might promote haematopoiesis and thrombopoiesis in the mouse model through (i) directly promoting the growth of megakaryocytes; (ii) indirectly promoting the growth of bone marrow stromal cells; (iii) inhibiting apoptosis of megakaryocytes.