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Targeting of cancer stem cells (CSC) is expected to be a paradigm-shifting approach for the treatment of cancers. Cell surface proteoglycans bearing sulfated glycosaminoglycan (GAG) chains are known to play a critical role in the regulation of stem cell fate. Here,we show for the first time that G2.2,a sulfated nonsaccharide GAG mimetic (NSGM) of heparin hexasaccharide,selectively inhibits colonic CSCs in vivo G2.2-reduced CSCs (CD133+/CXCR4+,Dual hi) induced HT-29 and HCT 116 colon xenografts' growth in a dose-dependent fashion. G2.2 also significantly delayed the growth of colon xenograft further enriched in CSCs following oxaliplatin and 5-fluorouracil treatment compared with vehicle-treated xenograft controls. In fact,G2.2 robustly inhibited CSCs' abundance (measured by levels of CSC markers,e.g.,CD133,DCMLK1,LGR5,and LRIG1) and self-renewal (quaternary spheroids) in colon cancer xenografts. Intriguingly,G2.2 selectively induced apoptosis in the Dual hi CSCs in vivo eluding to its CSC targeting effects. More importantly,G2.2 displayed none to minimal toxicity as observed through morphologic and biochemical studies of vital organ functions,blood coagulation profile,and ex vivo analyses of normal intestinal (and bone marrow) progenitor cell growth. Through extensive in vitro,in vivo,and ex vivo mechanistic studies,we showed that G2.2's inhibition of CSC self-renewal was mediated through activation of p38$\alpha$,uncovering important signaling that can be targeted to deplete CSCs selectively while minimizing host toxicity. Hence,G2.2 represents a first-in-class (NSGM) anticancer agent to reduce colorectal CSCs. View Publication

Osteoarthritis (OA) is characterized by cartilage degradation and chronic joint inflammation. Mesenchymal stem cells (MSCs) have shown promising results in OA,but their mechanism of action is not fully understood. We hypothesize that MSCs polarize macrophages,which are strongly associated with joint inflammation to more homeostatic sub-types. We tracked ferumoxytol (Feraheme™,iron oxide nanoparticle)-labeled murine MSCs (Fe-MSCs) in murine OA joints,and quantified changes to joint inflammation and fibrosis. 10-week-old C57BL/6 male mice (n = 5/group) were induced to undergo osteoarthritis by destabilization of medical meniscus (DMM) or sham surgery. 3 weeks post-surgery,mice were injected intra-articularly with either fluorescent dye-(DiR) labeled or DiR-Fe-MSC or saline to yield 4 groups (n = 5 per group for each timepoint [1,2 and 4weeks]). 4 weeks after injection,mice were imaged by MRI,and scored for i) OARSI (Osteoarthritis Research Society International) to determine cartilage damage; ii) immunohistochemical changes in iNOS,CD206,F4/80 and Prussian Blue/Sca-1 to detect pro-inflammatory,homeostatic and total macrophages and ferumoxytol -labeled MSCs respectively,and iii) Masson's Trichrome to detect changes in fibrosis. Ferumoxytol-labeled MSCs persisted at greater levels in DMM vs. SHAM-knee joints. We observed no difference in OARSI scores between MSC and vehicle groups. Sca-1 and Prussian Blue co-staining confirmed the ferumoxytol label resides in MSCs,although some ferumoxytol label was detected in proximity to MSCs in macrophages,likely due to phagocytosis of apoptotic MSCs,increasing functionality of these macrophages through MSC efferocytosis. MRI hypertintensity scores related to fluid edema decreased in MSC-treated vs. control animals. For the first time,we show that MSC-treated mice had increased ratios of {\%}CD206+: {\%}F4/80+ (homeostatic macrophages) (p{\textless}0.05),and decreased ratios of {\%}iNOS+: {\%}F4/80+ macrophages (p{\textless}0.01),supporting our hypothesis that MSCs may modulate synovial inflammation. View Publication

ABSTRACTRAD50?interacting protein1 (RINT1) deficiency has been implicated in recurrent acute liver failure (RALF) triggered by fever or infections. RINT1,together with neuroblastoma amplified sequence and Zeste White 10 (forming the NRZ complex),localizes at the interface between the endoplasmic reticulum and Golgi apparatus,where it plays a key role in vesicular trafficking. However,the mechanisms by which RINT1 deficiency leads to RALF remain unclear. This study aimed to describe a woman with RALF harboring a homozygous missense mutation in RINT1. Induced pluripotent stem cells (iPSCs) were generated from the patient's mononuclear cells and differentiated into hepatocyte?like cells (HLCs). Upon exposure to high temperature (40°C),RINT1?deficient HLCs exhibited cellular damage characteristic of RALF. Furthermore,these cells also demonstrated heightened sensitivity to cytokines and viral mimetics while showing comparatively lower responsiveness to bacterial infection?related stimuli. Transcriptome sequencing revealed dysregulated gene expression associated with the extracellular matrix (ECM). Additionally,glycosaminoglycan disaccharide analysis revealed abnormal levels of chondroitin sulfate,heparan sulfate,and hyaluronan in RINT1?deficient HLCs. In conclusion,HLCs derived from RINT1?deficient iPSCs serve as a valuable model for investigating RINT1?related liver pathogenesis. The results suggest that cytokine responses,particularly those triggered by viral infections,play a central role in the development of RALF. Furthermore,ECM alterations provided novel insights into the potential role of RINT1 defects in RALF. RAD50?interacting protein1 (RINT1) deficiency causes recurrent acute liver failure (RALF) during fever or infections. To investigate its underlying mechanism,induced pluripotent stem cells were generated from a patient with RINT1 deficiency and differentiated into hepatocyte?like cells (HLCs). RINT1?deficient HLCs exhibited damage resembling RALF when exposed to high temperatures and were more susceptible to cytokines and viral mimetics than to bacterial infection?related factors. Furthermore,RNA?seq and disaccharide analyses revealed dysregulation of extracellular matrix?related genes and abnormalities in extracellular matrix levels. View Publication

Evaluating cell metabolism is crucial during pluripotent stem cell (PSC) differentiation and somatic cell reprogramming as it affects cell fate. As cultured stem cells are heterogeneous,a comparative analysis of relative metabolism using existing metabolic analysis methods is difficult,resulting in inaccuracies. In this study,we measured human PSC basal metabolic levels using a Seahorse analyzer. We used fibroblasts,human induced PSCs,and human embryonic stem cells to monitor changes in basal metabolic levels according to cell number and determine the number of cells suitable for analysis. We evaluated normalization methods using glucose and selected the most suitable for the metabolic analysis of heterogeneous PSCs during the reprogramming stage. The response of fibroblasts to glucose increased with starvation time,with oxygen consumption rate and extracellular acidification rate responding most effectively to glucose 4 hours after starvation and declining after 5 hours of starvation. Fibroblasts and PSCs achieved appropriate responses to glucose without damaging their metabolism 2?4 and 2?3 hours after starvation,respectively. We developed a novel method for comparing basal metabolic rates of fibroblasts and PSCs,focusing on quantitative analysis of glycolysis and oxidative phosphorylation using glucose without enzyme inhibitors. This protocol enables efficient comparison of energy metabolism among cell types,including undifferentiated PSCs,differentiated cells,and cells undergoing cellular reprogramming,and addresses critical issues,such as differences in basal metabolic levels and sensitivity to normalization,providing valuable insights into cellular energetics. View Publication

ObjectivesMutations in Tissue Inhibitor of Metalloproteinases 3 (TIMP3) cause Sorsby's Fundus Dystrophy (SFD),a dominantly inherited,rare form of macular degeneration that results in vision loss. TIMP3 is synthesized primarily by retinal pigment epithelial (RPE) cells,which constitute the outer blood-retinal barrier. One major function of RPE is the synthesis and transport of vital nutrients,such as glucose,to the retina. Recently,metabolic dysfunction in RPE cells has emerged as an important contributing factor in retinal degenerations. We set out to determine if RPE metabolic dysfunction was contributing to SFD pathogenesis.MethodsQuantitative proteomics was conducted on RPE of mice expressing the S179C variant of TIMP3,known to be causative of SFD in humans. Proteins found to be differentially expressed (P < 0.05) were analyzed using statistical overrepresentation analysis to determine enriched pathways,processes,and protein classes using g:profiler and PANTHER Gene Ontology. We examined the effects of mutant TIMP3 on RPE metabolism using human ARPE-19 cells expressing mutant S179C TIMP3 and patient-derived induced pluripotent stem cell-derived RPE (iRPE) carrying the S204C TIMP3 mutation. RPE metabolism was directly probed using isotopic tracing coupled with GC/MS analysis. Steady state [U–13C6] glucose isotopic tracing was preliminarily conducted on S179C ARPE-19 followed by [U–13C6] glucose and [U–13C5] glutamine isotopic tracing in SFD iRPE cells.ResultsQuantitative proteomics and enrichment analysis conducted on RPE of mice expressing mutant S179C TIMP3 identified differentially expressed proteins that were enriched for metabolism-related pathways and processes. Notably these results highlighted dysregulated glycolysis and glucose metabolism. Stable isotope tracing experiments with [U–13C6] glucose demonstrated enhanced glucose utilization and glycolytic activity in S179C TIMP3 APRE-19 cells. Similarly,[U–13C6] glucose tracing in SFD iRPE revealed increased glucose contribution to glycolysis and the TCA cycle. Additionally,[U–13C5] glutamine tracing found evidence of altered malic enzyme activity.ConclusionsThis study provides important information on the dysregulation of RPE glucose metabolism in SFD and implicates a potential commonality with other retinal degenerative diseases,emphasizing RPE cellular metabolism as a therapeutic target. Highlights•SFD mice display alterations in proteins associated with metabolism.•SFD RPE cells have increased glycolytic activity and glucose contribution to the TCA cycle.•Glutamine contribution to energy metabolism is unaltered in SFD RPE cells however there is reduced malic enzyme activity.•SFD RPE cells display metabolic dysfunction potentially implicating metabolism as a viable therapeutic target. View Publication

SummaryGABAergic interneurons are inhibitory neurons of the CNS,playing a fundamental role in neural circuitry and activity. Here,we provide a robust protocol for the successful enrichment of human cerebellar GABAergic interneurons from human induced pluripotent stem cells (iPSCs) and measuring intracellular calcium transients. We describe in detail steps for culturing iPSCs; generating embryoid bodies; and differentiating and enriching for cerebellar GABAergic neurons (cGNs),with precise steps for their molecular characterization. We then detail the procedure for adeno-associated virus-mediated transduction of cGNs with genetically encoded calcium indicators,followed by intracellular calcium imaging and analyses.For complete details on the use and execution of this protocol,please refer to Pilotto et al.1 Graphical abstract Highlights•Steps described for generating GABAergic neurons from human iPSCs•Instructions for the enrichment of cerebellar GABAergic interneurons (cGNs)•Guide to calcium imaging of cGNs using genetically encoded calcium indicators Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. GABAergic interneurons are inhibitory neurons of the CNS,playing a fundamental role in neural circuitry and activity. Here,we provide a robust protocol for the successful enrichment of human-cerebellar GABAergic interneurons from human induced pluripotent stem cells (iPSCs) and measuring intracellular calcium transients. We describe in detail steps for culturing iPSCs,and generating embryoid bodies,differentiating and enriching for cerebellar GABAergic neurons (cGNs),with precise steps for their molecular characterization. We then detail the procedure for adeno-associated virus-mediated transduction of cGNs with genetically encoded calcium indicators,followed by intracellular calcium imaging and analyses. View Publication

The airway epithelium provides a first line of defense against pathogens by release of antimicrobial factors and neutrophil-attracting chemokines. Pseudomonas (P.) aeruginosa,a Gram-negative bacterium that expresses flagellin as an important virulence factor,is a common cause of injurious airway inflammation. The aim of our study was to determine the contribution of flagellin to the inflammatory,antimicrobial,and metabolic responses of the airway epithelium to P. aeruginosa . Furthermore,as we previously showed that targeting mTOR limited the glycolytic and inflammatory response induced by flagellin,we assessed the effect of rapamycin on human bronchial epithelial (HBE) cells stimulated with flagellated and non-flagellated P. aeruginosa. Primary pseudostratified HBE cells,cultured on an air-liquid-interface,were treated on the basolateral side with medium,vehicle or rapamycin,exposed on the apical side with flagellated or flagellin-deficient P. aeruginosa,and analyzed for their inflammatory,antimicrobial,and glycolytic responses. Flagellin augmented the P. aeruginosa -induced expression of antimicrobial factors and secretion of chemokines by HBE cells but did not further increase the glycolytic response. Treatment of HBE cells with rapamycin inhibited mTOR activation in general and flagellin-augmented mTOR activation in particular,but did not affect the glycolytic response. Rapamycin,however,diminished the flagellin-augmented inflammatory and antimicrobial response induced by Pseudomonas . These results demonstrate that flagellin is a significant factor that augments the inflammatory and antimicrobial response of human airway epithelial cells upon exposure to P. aeruginosa and suggest that mTOR inhibition by rapamycin in the airway epithelium diminishes these exaggerated responses. View Publication

Neural stem cell differentiation and the determination of lineage decision between neuronal and glial fates have important implications in the study of developmental,pathological,and regenerative processes. Although small molecule chemicals with the ability to control neural stem cell fate are considered extremely useful tools in this field,few were reported. AICAR is an adenosine analog and extensively used to activate AMP-activated protein kinase (AMPK),a metabolic fuel gauge" of the biological system. In the present study View Publication

MYH9 disorders such as May-Hegglin anomaly are characterized by macrothrombocytopenia and cytoplasmic granulocyte inclusion bodies that result from mutations in MYH9,the gene for nonmuscle myosin heavy chain-IIA (NMMHC-IIA). We examined the expression of mutant NMMHC-IIA polypeptide in peripheral blood cells from patients with MYH9 5770delG and 5818delG mutations. A specific antibody to mutant NMMHC-IIA (NT629) was raised against the abnormal carboxyl-terminal residues generated by 5818delG. NT629 reacted to recombinant 5818delG NMMHC-IIA but not to wild-type NMMHC-IIA,and did not recognize any cellular components of normal peripheral blood cells. Immunofluorescence and immunoblotting revealed that mutant NMMHC-IIA was present and sequestrated only in inclusion bodies within neutrophils,diffusely distributed throughout lymphocyte cytoplasm,sparsely localized on a diffuse cytoplasmic background in monocytes,and uniformly distributed at diminished levels only in large platelets. Mutant NMMHC-IIA did not translocate to lamellipodia in surface activated platelets. Wild-type NMMHC-IIA was homogeneously distributed among megakaryocytes derived from the peripheral blood CD34(+) cells of patients,but coarse mutant NMMHC-IIA was heterogeneously scattered without abnormal aggregates in the cytoplasm. We show the differential expression of mutant NMMHC-IIA and postulate that cell-specific regulation mechanisms function in MYH9 disorders. View Publication

Costimulatory signals are critical to T cell activation,but how their effects are mediated remains incompletely characterized. Here,we demonstrate that locally produced C5a and C3a anaphylatoxins interacting with their G protein-coupled receptors (GPCRs),C5aR and C3aR,on APCs and T cells both upstream and downstream of CD28 and CD40L signaling are integrally involved in T cell proliferation and differentiation. Disabling these interactions reduced MHC class II and costimulatory-molecule expression and dramatically diminished T cell responses. Importantly,impaired T cell activation by Cd80-/-Cd86-/- and Cd40-/- APCs was reconstituted by added C5a or C3a. C5aR and C3aR mediated their effects via PI-3 kinase-gamma-dependent AKT phosphorylation,providing a link between GPCR signaling,CD28 costimulation,and T cell survival. These local paracrine and autocrine interactions thus operate constitutively in naive T cells to maintain viability,and their amplification by cognate APC partners thus is critical to T cell costimulation. View Publication

BACKGROUND Pluripotency,the property of a cell to differentiate into all cellular types of a given organism,is central to the development of stem cell-based therapies and regenerative medicine. Stem cell pluripotency is the result of the orchestrated activation of a complex transcriptional network characterized by the expression of a set of transcription factors including the master regulators of pluripotency Nanog and Oct4. Recently,it has been shown that pluripotency can be induced in somatic cells by viral-mediated expression of the transcription factors Oct3/4,Sox2,Klf4,and c-Myc. RESULTS Here we show that 5-Aminoimidazole-4-carboxamide-1-b-riboside (AICAR) is able to activate the molecular circuitry of pluripotency in mouse embryonic stem cells (mESC) and maintain Nanog and Oct4 expression in mESC exposed to the differentiating agent retinoic acid. We also show that AICAR is able to induce Klf4,Klf2 and Myc expression in both mESC and murine fibroblasts. CONCLUSION AICAR is able to activate the molecular circuitry of pluripotency in mESC and to induce the expression of several key regulators of pluripotency in somatic cells. AICAR is therefore a useful pharmacological entity for studying small molecule mediated induction of pluripotency. View Publication

The amyloid-beta precursor protein (AbetaPP) is a ubiquitously expressed transmembrane protein whose cleavage product,the amyloid-beta (Abeta) protein,is deposited in amyloid plaques in neurodegenerative conditions such as Alzheimer disease,Down syndrome,and head injury. We recently reported that this protein,normally associated with neurodegenerative conditions,is expressed by human embryonic stem cells (hESCs). We now report that the differential processing of AbetaPP via secretase enzymes regulates the proliferation and differentiation of hESCs. hESCs endogenously produce amyloid-beta,which when added exogenously in soluble and fibrillar forms but not oligomeric forms markedly increased hESC proliferation. The inhibition of AbetaPP cleavage by beta-secretase inhibitors significantly suppressed hESC proliferation and promoted nestin expression,an early marker of neural precursor cell (NPC) formation. The induction of NPC differentiation via the non-amyloidogenic pathway was confirmed by the addition of secreted AbetaPPalpha,which suppressed hESC proliferation and promoted the formation of NPCs. Together these data suggest that differential processing of AbetaPP is normally required for embryonic neurogenesis. View Publication