Jaiswal RK et al. (MAR 2000)
The Journal of biological chemistry 275 13 9645--52
Adult human mesenchymal stem cell differentiation to the osteogenic or adipogenic lineage is regulated by mitogen-activated protein kinase.
Adult human mesenchymal stem cells are primary,multipotent cells capable of differentiating to osteocytic,chondrocytic,and adipocytic lineages when stimulated under appropriate conditions. To characterize the molecular mechanisms that regulate osteogenic differentiation,we examined the contribution of mitogen-activated protein kinase family members,ERK,JNK,and p38. Treatment of these stem cells with osteogenic supplements resulted in a sustained phase of ERK activation from day 7 to day 11 that coincided with differentiation,before decreasing to basal levels. Activation of JNK occurred much later (day 13 to day 17) in the osteogenic differentiation process. This JNK activation was associated with extracellular matrix synthesis and increased calcium deposition,the two hallmarks of bone formation. Inhibition of ERK activation by PD98059,a specific inhibitor of the ERK signaling pathway,blocked the osteogenic differentiation in a dose-dependent manner,as did transfection with a dominant negative form of MAP kinase kinase (MEK-1). Significantly,the blockage of osteogenic differentiation resulted in the adipogenic differentiation of the stem cells and the expression of adipose-specific mRNAs peroxisome proliferator-activated receptor gamma2,aP2,and lipoprotein lipase. These observations provide a potential mechanism involving MAP kinase activation in osteogenic differentiation of adult stem cells and suggest that commitment of hMSCs into osteogenic or adipogenic lineages is governed by activation or inhibition of ERK,respectively.
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Lee SJ et al. (DEC 2014)
Stem Cells and Development 23 23 2831--2840
Adult Stem Cells from the Hyaluronic Acid-Rich Node and Duct System Differentiate into Neuronal Cells and Repair Brain Injury
The existence of a hyaluronic acid-rich node and duct system (HAR-NDS) within the lymphatic and blood vessels was demonstrated previously. The HAR-NDS was enriched with small (3.0-5.0 μm in diameter),adult stem cells with properties similar to those of the very small embryonic-like stem cells (VSELs). Sca-1(+)Lin(-)CD45(-) cells were enriched approximately 100-fold in the intravascular HAR-NDS compared with the bone marrow. We named these adult stem cells node and duct stem cells (NDSCs)." NDSCs formed colonies on C2C12 feeder layers were positive for fetal alkaline phosphatase and could be subcultured on the feeder layers. NDSCs were Oct4(+)Nanog(+)SSEA-1(+)Sox2(+) while VSELs were Oct4(+)Nanog(+)SSEA-1(+)Sox2(-). NDSCs had higher sphere-forming efficiency and proliferative potential than VSELs and they were found to differentiate into neuronal cells in vitro. Injection of NDSCs into mice partially repaired ischemic brain damage. Thus we report the discovery of potential adult stem cells that may be involved in tissue regeneration. The intravascular HAR-NDS may serve as a route that delivers these stem cells to their target tissues.
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Kang HS et al. (DEC 2015)
Journal of Korean medical science 30 12 1764--76
Advanced Properties of Urine Derived Stem Cells Compared to Adipose Tissue Derived Stem Cells in Terms of Cell Proliferation, Immune Modulation and Multi Differentiation.
Adipose tissue stem cells (ADSCs) would be an attractive autologous cell source. However,ADSCs require invasive procedures,and has potential complications. Recently,urine stem cells (USCs) have been proposed as an alternative stem cell source. In this study,we compared USCs and ADSCs collected from the same patients on stem cell characteristics and capacity to differentiate into various cell lineages to provide a useful guideline for selecting the appropriate type of cell source for use in clinical application. The urine samples were collected via urethral catheterization,and adipose tissue was obtained from subcutaneous fat tissue during elective laparoscopic kidney surgery from the same patient (n = 10). Both cells were plated for primary culture. Cell proliferation,colony formation,cell surface markers,immune modulation,chromosome stability and multi-lineage differentiation were analyzed for each USCs and ADSCs at cell passage 3,5,and 7. USCs showed high cell proliferation rate,enhanced colony forming ability,strong positive for stem cell markers expression,high efficiency for inhibition of immune cell activation compared to ADSCs at cell passage 3,5,and 7. In chromosome stability analysis,both cells showed normal karyotype through all passages. In analysis of multi-lineage capability,USCs showed higher myogenic,neurogenic,and endogenic differentiation rate,and lower osteogenic,adipogenic,and chondrogenic differentiation rate compared to ADSCs. Therefore,we expect that USC can be an alternative autologous stem cell source for muscle,neuron and endothelial tissue reconstruction instead of ADSCs.
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(Jul 2024)
PLOS Pathogens 20 7
Advances in an
The emergence of drug-resistant Mycobacterium tuberculosis (M.tb) has led to the development of novel anti-tuberculosis (anti-TB) drugs. Common methods for testing the efficacy of new drugs,including two-dimensional cell culture models or animal models,have several limitations. Therefore,an appropriate model representative of the human organism is required. Here,we developed an M.tb infection model using human lung organoids (hLOs) and demonstrated that M.tb H37Rv can infect lung epithelial cells and human macrophages (hM?s) in hLOs. This novel M.tb infection model can be cultured long-term and split several times while maintaining a similar number of M.tb H37Rv inside the hLOs. Anti-TB drugs reduced the intracellular survival of M.tb in hLOs. Notably,M.tb growth in hLOs was effectively suppressed at each passage by rifampicin and bedaquiline. Furthermore,a reduction in inflammatory cytokine production and intracellular survival of M.tb were observed upon knockdown of MFN2 and HERPUD1 (host-directed therapeutic targets for TB) in our M.tb H37Rv-infected hLO model. Thus,the incorporation of hM?s and M.tb into hLOs provides a powerful strategy for generating an M.tb infection model. This model can effectively reflect host-pathogen interactions and be utilized to test the efficacy of anti-TB drugs and host-directed therapies. Author summaryEstablishment of M.tb infection model is imperative to develop new anti-TB drugs based on the pathogenesis of TB. Various animal models,including mice,rats,guinea pigs,non-human primates,rabbits,cattle,and zebrafish,are commonly used in TB research to mimic TB symptoms and study immune responses to M.tb infection. In vitro models,such as agent-based models allow examination of host-pathogen interactions,early granuloma formation and drug screening,providing cellular-level insights. However,these models may not fully represent human immunopathology owing to differences in immune cell distributions. Lung organoids mimic human lung dynamics and functions,providing crucial insights into immune responses to TB. In this study,an M.tb infection model developed using hLOs demonstrated infection of lung epithelial cells and human macrophages,reflecting host-pathogen interactions. This model is attractive for evaluating the efficacy of anti-TB drugs and host-directed therapies.
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Lu J et al. (OCT 2012)
Integrative biology : quantitative biosciences from nano to macro 4 10 1223--36
Advancing practical usage of microtechnology: a study of the functional consequences of dielectrophoresis on neural stem cells.
The integration of microscale engineering,microfluidics,and AC electrokinetics such as dielectrophoresis has generated novel microsystems that enable quantitative analysis of cellular phenotype,function,and physiology. These systems are increasingly being used to assess diverse cell types,such as stem cells,so it becomes critical to thoroughly evaluate whether the systems themselves impact cell function. For example,engineered microsystems have been utilized to investigate neural stem/progenitor cells (NSPCs),which are of interest due to their potential to treat CNS disease and injury. Analysis by dielectrophoresis (DEP) microsystems determined that unlabeled NSPCs with distinct fate potential have previously unrecognized distinguishing electrophysiological characteristics,suggesting that NSPCs could be isolated by DEP microsystems without the use of cell type specific labels. To gauge the potential impact of DEP sorting on NSPCs,we investigated whether electric field exposure of varying times affected survival,proliferation,or fate potential of NSPCs in suspension. We found short-term DEP exposure (1 min or less) had no effect on NSPC survival,proliferation,or fate potential revealed by differentiation. Moreover,NSPC proliferation (measured by DNA synthesis and cell cycle kinetics) and fate potential were not altered by any length of DEP exposure (up to 30 min). However,lengthy exposure (textgreater5 min) to frequencies near the crossover frequency (50-100 kHz) led to decreased survival of NSPCs (maximum ∼30% cell loss after 30 min). Based on experimental observations and mathematical simulations of cells in suspension,we find that frequencies near the crossover frequency generate an induced transmembrane potential that results in cell swelling and rupture. This is in contrast to the case for adherent cells since negative DEP frequencies lower than the crossover frequency generate the highest induced transmembrane potential and damage for these cells. We clarify contrasting effects of DEP on adherent and suspended cells,which are related to the cell position within the electric field and the strength of the electric field at specific distances from the electrodes. Modeling of electrode configurations predicts optimal designs to induce cell movement by DEP while limiting the induced transmembrane potential. We find DEP electric fields are not harmful to stem cells in suspension at short exposure times,thus providing a basis for developing DEP-based applications for stem cells.
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(May 2025)
Molecular Medicine 31 4
AEOL-induced NRF2 activation and DWORF overexpression mitigate myocardial I/R injury
BackgroundThe causal relationship between the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and the preservation of SERCA2a function in mitigating myocardial ischemia–reperfusion (mI/R) injury,along with the associated regulatory mechanisms,remains incompletely understood. This study aims to unravel how NRF2 directly or indirectly influences SERCA2a function and its regulators,phospholamban (PLN) and Dwarf Open Reading Frame (DWORF),by testing the pharmacological repositioning of AEOL-10150 (AEOL) in the context of mI/R injury.MethodsC57BL6/J,Nrf2 knockout (Nrf2?/?),and wild-type (Nrf2+/+) mice,as well as human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) were subjected to I/R injury. Gain/loss of function techniques,RT-qPCR,western blotting,LC/MS/MS,and fluorescence spectroscopy were utilized. Cardiac dimensions and function were assessed by echocardiography.ResultsIn the early stages of mI/R injury,AEOL administration reduced mitochondrial ROS production,decreased myocardial infarct size,and improved cardiac function. These effects were due to NRF2 activation,leading to the overexpression of the micro-peptide DWORF,consequently enhancing SERCA2a activity. The cardioprotective effect induced by AEOL was diminished in Nrf2?/? mice and in Nrf2/Dworf knockdown models in hiPSCMs subjected to simulated I/R injury. Our data show that AEOL-induced NRF2-mediated upregulation of DWORF disrupts the phospholamban-SERCA2a interaction,leading to enhanced SERCA2a activation and improved cardiac function.ConclusionsTaken together,our study reveals that AEOL-induced NRF2-mediated overexpression of DWORF enhances myocardial function through the activation of the SERCA2a offering promising therapeutic avenues for mI/R injury.Supplementary InformationThe online version contains supplementary material available at 10.1186/s10020-025-01242-1. Highlights• Novel AEOL-10150 therapeutic potential. AEOL-10150 demonstrates promise in activating NRF2 and mitigating myocardial ischemia-reperfusion injury.• DWORF overexpression breakthrough. Overexpression of DWORF significantly contributes to preserving cardiac function and reducing myocardial injury through the NRF2-DWORF pathway.• Enhanced cardiac protection mechanisms. The study highlights the dual role of AEOL-10150 and DWORF in enhancing cardiac protection and preventing heart failure.• Future research directions. Additional studies are required to validate the long-term efficacy of AEOL-10150 and the regulatory effects of NRF2-DWORF axis in clinical applications.Supplementary InformationThe online version contains supplementary material available at 10.1186/s10020-025-01242-1.
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A. Leonard et al. (MAY 2018)
Journal of molecular and cellular cardiology 118 147--158
Afterload promotes maturation of human induced pluripotent stem cell derived cardiomyocytes in engineered heart tissues.
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) grown in engineered heart tissue (EHT) can be used for drug screening,disease modeling,and heart repair. However,the immaturity of hiPSC-CMs currently limits their use. Because mechanical loading increases during development and facilitates cardiac maturation,we hypothesized that afterload would promote maturation of EHTs. To test this we developed a system in which EHTs are suspended between a rigid post and a flexible one,whose resistance to contraction can be modulated by applying braces of varying length. These braces allow us to adjust afterload conditions over two orders of magnitude by increasing the flexible post resistance from 0.09 up to 9.2 mu$N/mu$m. After three weeks in culture,optical tracking of post deflections revealed that auxotonic twitch forces increased in correlation with the degree of afterload,whereas twitch velocities decreased with afterload. Consequently,the power and work of the EHTs were maximal under intermediate afterloads. When studied isometrically,the inotropy of EHTs increased with afterload up to an intermediate resistance (0.45 mu$N/mu$m) and then plateaued. Applied afterload increased sarcomere length,cardiomyocyte area and elongation,which are hallmarks of maturation. Furthermore,progressively increasing the level of afterload led to improved calcium handling,increased expression of several key markers of cardiac maturation,including a shift from fetal to adult ventricular myosin heavy chain isoforms. However,at the highest afterload condition,markers of pathological hypertrophy and fibrosis were also upregulated,although the bulk tissue stiffness remained the same for all levels of applied afterload tested. Together,our results indicate that application of moderate afterloads can substantially improve the maturation of hiPSC-CMs in EHTs,while high afterload conditions may mimic certain aspects of human cardiac pathology resulting from elevated mechanical overload.
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(Feb 2025)
Journal of Nanobiotechnology 23 5
AG73-GelMA/AlgMA hydrogels provide a stable microenvironment for the generation of pancreatic progenitor organoids
Patient specific induced pluripotent stem cells (iPSCs) derived ? cells represent an effective means for disease modeling and autologous diabetes cell replacement therapy. In this study,an AG73-5%gelatin methacryloyl (GelMA) /2% alginate methacrylate (AlgMA) hydrogel was employed to generate pancreatic progenitor (PP) organoids and improve stem cell-derived ? (SC-?) cell differentiation protocol. The laminin-derived homolog AG73,which mimics certain cell?matrix interactions,facilitates AKT signaling pathway activation to promote PDX1+/NKX6.1+ PP organoid formation and effectively modulates subsequent epithelial–mesenchymal transition (EMT) in the endocrine lineage. The 5%GelMA/2%AlgMA hydrogel mimics the physiological stiffness of the pancreas,providing the optimal mechanical stress and spatial structure for PP organoid differentiation. The Syndecan-4 (SDC4)-ITGAV complex plays a pivotal role in the early stages of pancreatic development by facilitating the formation of SOX9+/PDX1+ bipotent PPs. Our findings demonstrate that AG73-GelMA/AlgMA hydrogel-derived SC-? cells exhibit enhanced insulin secretion and accelerated hyperglycemia reversal in vivo. This study presents a cost-effective,stable,and efficient alternative for the comprehensive 3D culture of SC-? cells in vitro by mitigating the uncertainties associated with conventional culture methods.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12951-025-03266-5. Graphical Abstract
Supplementary InformationThe online version contains supplementary material available at 10.1186/s12951-025-03266-5.
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M. L. Stone et al. (Nov 2024)
iScience 27 12
Agarose hydrogel-mediated electroporation method for retinal tissue cultured at the air-liquid interface
It is advantageous to culture the ex vivo retina and other tissues at the air-liquid interface to allow for more efficient gas exchange. However,gene delivery to these cultures can be challenging. Electroporation is a fast and robust method of gene delivery,but typically requires submergence in liquid buffer for electrical current flow. We have developed a submergence-free electroporation technique that incorporates an agarose hydrogel disk between the positive electrode and retina. Inner retinal neurons and Müller glia are transfected with increased propensity toward Müller glia transfection after extended time in culture. We also observed an increase in BrdU incorporation in Müller glia following electrical stimulation,and variation in detection of transfected cells from expression vectors with different promoters. This method advances our ability to use ex vivo retinal tissue for genetic studies and should be adaptable for other tissues cultured at an air-liquid interface. Subject areas: Genetic engineering,Methodology in biological sciences,Bioelectrical engineering
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T. Kwok et al. ( 2022)
Frontiers in aging 3 838943
Age-Associated Changes to Lymph Node Fibroblastic Reticular Cells.
The decreased proportion of antigen-inexperienced,na{\{i}}ve T cells is a hallmark of aging in both humans and mice and contributes to reduced immune responses particularly against novel and re-emerging pathogens. Na{\"{i}}ve T cells depend on survival signals received during their circulation among the lymph nodes by direct contacts with stroma in particular fibroblastic reticular cells. Macroscopic changes to the architecture of the lymph nodes have been described but it is unclear how lymph node stroma are altered with age and whether these changes contribute to reduced na{\"{i}}ve T cell maintenance. Here using 2-photon microscopy we determined that the aged lymph node displayed increased fibrosis and correspondingly that na{\"{i}}ve T-cell motility was impaired in the aged lymph node especially in proximity to fibrotic deposition. Functionally adoptively transferred young na{\"{i}}ve T-cells exhibited reduced homeostatic turnover in aged hosts supporting the role of T cell-extrinsic mechanisms that regulate their survival. Further we determined that early development of resident fibroblastic reticular cells was impaired which may correlate to the declining levels of na{\"{i}}ve T-cell homeostatic factors observed in aged lymph nodes. Thus our study addresses the controversy as to whether aging impacts the composition lymph node stroma and supports a model in which impaired differentiation of lymph node fibroblasts and increased fibrosis inhibits the interactions necessary for na{\"{i}}ve T cell homeostasis."
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H. Mkhikian et al. (mar 2022)
Nature aging 2 3 231--242
Age-associated impairment of T cell immunity is linked to sex-dimorphic elevation of N-glycan branching.
Impaired T cell immunity with aging increases mortality from infectious disease. The branching of Asparagine-linked glycans is a critical negative regulator of T cell immunity. Here we show that branching increases with age in females more than males,in na{\{i}}ve more than memory T cells and in CD4+ more than CD8+ T cells. Female sex hormones and thymic output of na{\"{i}}ve T cells (TN) decrease with age however neither thymectomy nor ovariectomy altered branching. Interleukin-7 (IL-7) signaling was increased in old female more than male mouse TN cells and triggered increased branching. N-acetylglucosamine a rate-limiting metabolite for branching increased with age in humans and synergized with IL-7 to raise branching. Reversing elevated branching rejuvenated T cell function and reduced severity of Salmonella infection in old female mice. These data suggest sex-dimorphic antagonistic pleiotropy where IL-7 initially benefits immunity through TN maintenance but inhibits TN function by raising branching synergistically with age-dependent increases in N-acetylglucosamine."
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