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A brefeldin A (BFA)-inhibited guanine nucleotide-exchange protein (GEP) for ADP-ribosylation factors (ARF) was purified earlier from bovine brain cytosol. Cloning and expression of the cDNA confirmed that the recombinant protein (p200) is a BFA-sensitive ARF GEP. p200 contains a domain that is 50% identical in amino acid sequence to a region in yeast Sec7,termed the Sec7 domain. Sec7 domains have been identified also in other proteins with ARF GEP activity,some of which are not inhibited by BFA. To identify structural elements that influence GEP activity and its BFA sensitivity,several truncated mutants of p200 were made. Deletion of sequence C-terminal to the Sec7 domain did not affect GEP activity. A protein lacking 594 amino acids at the N terminus,as well as sequence following the Sec7 domain,also had high activity. The mutant lacking 630 N-terminal amino acids was,however,only 1% as active,as was the Sec7 domain itself (mutant lacking 697 N-terminal residues). It appears that the Sec7 domain of p200 contains the catalytic site but additional sequence (perhaps especially that between positions 595 and 630) modifies activity dramatically. Myristoylated recombinant ARFs were better than non-myristoylated as substrates; ARFs 1 and 3 were better than ARF5,and no activity was detected with ARF6. Physical interaction of the Sec7 domain with an ARF1 mutant was demonstrated,but it was much weaker than that of the cytohesin-1 Sec7 domain with the same ARF protein. Effects of BFA on p200 and all mutants with high activity were similar with approximately 50% inhibition at textless/=50 microM. The inactive BFA analogue B36 did not inhibit the Sec7 domain or p200. Thus,the Sec7 domain of p200,like that of Sec7 itself (Sata,M.,Donaldson,J. G.,Moss,J.,and Vaughan,M. (1998) Proc. Natl. Acad. Sci. U. S. A. 95,4204-4208),plays a role in BFA inhibition as well as in GEP activity,although the latter is markedly modified by other structural elements. View Publication

T-cell-mediated processes play an essential role in the pathogenesis of several inflammatory skin diseases such as atopic dermatitis,allergic contact dermatitis and psoriasis. The aim of this study was to investigate the role of the IL-2-inducible tyrosine kinase (Itk),an enzyme acting downstream of the T-cell receptor (TCR),in T-cell-dependent skin inflammation using three approaches. Itk knockout mice display significantly reduced inflammatory symptoms in mouse models of acute and subacute contact hypersensitivity (CHS) reactions. Systemic administration of a novel small molecule Itk inhibitor,Compound 44,created by chemical optimization of an initial high-throughput screening hit,inhibited Itk's activity with an IC50 in the nanomolar range. Compound 44 substantially reduced proinflammatory immune responses in vitro and in vivo after systemic administration in two acute CHS models. In addition,our data reveal that human Itk,comparable to its murine homologue,is expressed mainly in T cells and is increased in lesional skin from patients with atopic dermatitis and allergic contact dermatitis. Finally,silencing of Itk by RNA interference in primary human T cells efficiently blocks TCR-induced lymphokine secretion. In conclusion,Itk represents an interesting new target for the therapy of T-cell-mediated inflammatory skin diseases. View Publication

BACKGROUND The incidence of neurological complications and fatalities associated with Hand,Foot & Mouth disease has increased over recent years,due to emergence of newly-evolved strains of Enterovirus 71 (EV71). In the search for new antiviral therapeutics against EV71,accurate and sensitive in vitro cellular models for preliminary studies of EV71 pathogenesis is an essential prerequisite,before progressing to expensive and time-consuming live animal studies and clinical trials. METHODS This study thus investigated whether neural lineages derived from pluripotent human embryonic stem cells (hESC) can fulfil this purpose. EV71 infection of hESC-derived neural stem cells (NSC) and mature neurons (MN) was carried out in vitro,in comparison with RD and SH-SY5Y cell lines. RESULTS Upon assessment of post-infection survivability and EV71 production by the various types,it was observed that NSC were significantly more susceptible to EV71 infection compared to MN,RD (rhabdomyosarcoma) and SH-SY5Y cells,which was consistent with previous studies on mice. The SP81 peptide had significantly greater inhibitory effect on EV71 production by NSC and MN compared to the cancer-derived RD and SH-SY5Y cell lines. CONCLUSIONS Hence,this study demonstrates that hESC-derived neural lineages can be utilized as in vitro models for studying EV71 pathogenesis and for screening of antiviral therapeutics. View Publication

It is widely accepted that canonical Wnt (cWnt) signaling is required for the differentiation of osteoprogenitors into osteoblasts. Furthermore,tumor-derived secretion of the cWnt-antagonist Dickkopf-1 (Dkk-1) is known to cause bone destruction,inhibition of repair and metastasis in many bone malignancies,but its role in osteosarcoma (OS) is still under debate. In this study,we examined the role of Dkk-1in OS by engineering its overexpression in the osteochondral sarcoma line MOS-J. Consistent with the known role of Dkk-1 in osteoblast differentiation,Dkk-1 inhibited osteogenesis by the MOSJ cells themselves and also in surrounding tissue when implanted in vivo. Surprisingly,Dkk-1 also had unexpected effects on MOSJ cells in that it increased proliferation and resistance to metabolic stress in vitro and caused the formation of larger and more destructive tumors than controls upon orthotopic implantation. These effects were attributed in part to upregulation of the stress response enzyme and cancer stem cell marker aldehyde-dehydrogenase-1 (ALDH1). Direct inhibition of ALDH1 reduced viability under stressful culture conditions,whereas pharmacological inhibition of cWnt or overexpression of ALDH1 had a protective effect. Furthermore,we observed that ALDH1 was transcriptionally activated in a c-Jun-dependent manner through a pathway consisting of RhoA,MAP-kinase-kinase-4 and Jun N-terminal Kinase (JNK),indicating that noncanonical planar cell polarity-like Wnt signaling was the mechanism responsible. Together,our results therefore demonstrate that Dkk-1 enhances resistance of OS cells to stress by tipping the balance of Wnt signaling in favor of the non-canonical Jun-mediated Wnt pathways. In turn,this results in transcriptional activation of ALDH1 through Jun-responsive promoter elements. This is the first report linking Dkk-1 to tumor stress resistance,further supporting the targeting of Dkk-1 not only to prevent and treat osteolytic bone lesions but also to reduce numbers of stress-resistant tumor cells. View Publication

SummaryThyroid carcinoma represents the first malignancy among the endocrine organs. Investigating the cellular hierarchy and the mechanisms underlying the initiation of thyroid carcinoma is crucial in thyroid cancer research. Here,we present a protocol for deriving thyroid cell lineage from human embryonic stem cells. We also describe steps for engineering thyroid progenitor cells utilizing CRISPR-Cas9 technology,which can be used to perform in vivo studies,thus facilitating the development of representative thyroid tumorigenesis models.For complete details on the use and execution of this protocol,please refer to Veschi et al.1 Graphical abstract Highlights•Differentiation protocol for thyroid cell lineages from human embryonic stem cells•CRISPR-Cas9-mediated cellular engineering for common thyroid cancer genetic alteration•Orthotopic injection of thyroid progenitors to recapitulate thyroid cancer progression Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. Thyroid carcinoma represents the first malignancy among the endocrine organs. Investigating the cellular hierarchy and the mechanisms underlying the initiation of thyroid carcinoma is crucial in thyroid cancer research. Here,we present a protocol for deriving thyroid cell lineage from human embryonic stem cells. We also describe steps for engineering thyroid progenitor cells utilizing CRISPR-Cas9 technology,which can be used to perform in vivo studies,thus facilitating the development of representative thyroid tumorigenesis models. View Publication

Background and purpose: In this study,we applied an induced pluripotent stem cell (iPSC)-based model of inherited erythromelalgia (IEM) to screen a library of 281 small molecules,aiming to identify candidate pain-modulating compounds. Experimental approach: Human iPSC-derived sensory neuron-like cells,which exhibit action potentials in response to noxious stimulation,were evaluated using whole-cell patch-clamp and microelectrode array (MEA) techniques. Key results: Sensory neuron-like cells derived from individuals with IEM showed spontaneous electrical activity characteristic of genetic pain disorders. The drug screen identified four compounds (AZ106,AZ129,AZ037 and AZ237) that significantly decreased spontaneous firing with minimal toxicity. The calculated IC50 values indicate the potential efficacy of these compounds. Electrophysiological analysis confirmed the compounds' ability to reduce action potential generation in IEM patient-specific iPSC-derived sensory neuron-like cells. Conclusions and implications: Our screening approach demonstrates the reproducibility and effectiveness of human neuronal disease modelling offering a promising avenue for discovering new analgesics. These findings address a critical gap in current therapeutic strategies for both general and neuropathic pain,warranting further investigation. This study highlights the innovative use of patient-derived iPSC sensory neuronal models in pain research and emphasises the potential for personalised medicine in developing targeted analgesics. Key points: Utilisation of human iPSCs for efficient differentiation into sensory neuron-like cells offers a novel strategy for studying pain mechanisms. IEM sensory neuron-like cells exhibit key biomarkers and generate action potentials in response to noxious stimulation. IEM sensory neuron-like cells display spontaneous electrical activity,providing a relevant nociceptive model. Screening of 281 compounds identified four candidates that significantly reduced spontaneous firing with low cytotoxicity. Electrophysiological profiling of selected compounds revealed promising insights into their mechanisms of action,specifically modulating the NaV 1.7 channel for targeted analgesia. View Publication

Characterization and modeling of biological neural networks has emerged as a field driving significant advancements in our understanding of brain function and related pathologies. As of today,pharmacological treatments for neurological disorders remain limited,pushing the exploration of promising alternative approaches such as electroceutics. Recent research in bioelectronics and neuromorphic engineering have fostered the development of the new generation of neuroprostheses for brain repair. However,achieving their full potential necessitates a deeper understanding of biohybrid interaction. In this study,we present a novel real-time,biomimetic,cost-effective and user-friendly neural network capable of real-time emulation for biohybrid experiments. Our system facilitates the investigation and replication of biophysically detailed neural network dynamics while prioritizing cost-efficiency,flexibility and ease of use. We showcase the feasibility of conducting biohybrid experiments using standard biophysical interfaces and a variety of biological cells as well as real-time emulation of diverse network configurations. We envision our system as a crucial step towards the development of neuromorphic-based neuroprostheses for bioelectrical therapeutics,enabling seamless communication with biological networks on a comparable timescale. Its embedded real-time functionality enhances practicality and accessibility,amplifying its potential for real-world applications in biohybrid experiments. Beaubois et al. introduce a real-time biomimetic neural network for biohybrid experiments,providing a tool to study closed-loop applications for neuroscience and neuromorphic-based neuroprostheses. View Publication

BackgroundLung cancer has become one of the most fatal cancers at present. Traditional treatments showed limited therapeutic effects on lung cancer. The phototherapy has emerged as a powerful approach for lung cancer treatment. Aggregation-induced emission luminogens (AIEgens) exhibit excellent optical performance such as strong fluorescence,enhanced reactive oxygen species (ROS) generation,and effective thermal effect after aggregation,which show great potential in phototherapy. However,the disadvantages including hydrophobicity,low specificity,and short circulation lifetime limited their efficacy on cancer therapy.MethodsWe developed a biomimetic AIEgens constructed using CD8+ T cells membrane to camouflage the AIEgen C41H37N2O3S2 (named BITT) nanoparticles (termed TB). The prepared TB improved the tumor accumulation of AIEgen by PD-1/PD-L1 recognition on the CD8+ T and LLC cell membranes,respectively.ResultsThe prepared TB showed improved binding efficiency,photothermal effects,and ROS generation ability to kill the lung cancer cells. TB also showed improved circulation lifetime and excellent tumor targeting ability,leading to effective phototherapy and immunotherapy in vivo based on BITT and the CD8+ T cell-derived membranes. Based on the AIE and immune checkpoint blockade (ICB) strategies,TB enhanced the antitumor activities of lung cancer by phototherapy and immunotherapy.ConclusionThe present work developed a type of biomimetic AIEgens,which overcame the inherent limitations of conventional AIEgens and leveraged immune recognition for targeted tumor accumulation. Furthermore,the integration of AIE-driven phototherapy with immune checkpoint blockade demonstrated potent synergistic antitumor efficacy,establishing a promising combinatorial strategy against aggressive lung malignancies. View Publication

Transition from the manual processes that are performed during the initial research and development (R&D) stage to automated processes for later and commercial stage cell therapy manufacturing can be challenging. It often requires significant effort,time,and costs – which hinders the therapy’s access to the clinic. To ease this transition,we have developed a novel and flexible manufacturing platform,Bioreactor with Expandable Culture Area (BECA),that aims to support both R&D and manufacturing to accelerate cell therapies from bench to bedside. This report introduces two models in this manufacturing platform: BECA-S for manual small-scale operation at R&D phase and BECA-Auto for functionally closed and automated scaled-out operation at manufacturing phase. We employed these two models to streamline transition of the T cell culture process from manual to automated and reported insignificant differences in the culture outcome between the two. Our work represents the first detailed development and demonstration of a standalone cell manufacturing platform that facilitates a seamless transition between manual and automated processing for autologous T cell therapy manufacturing. View Publication

Differentiation of human embryonic stem (ES) and induced pluripotent stem (iPS) cells into hepatocyte-like cells provides a platform to study the molecular basis of human hepatocyte differentiation,to develop cell culture models of liver disease,and to potentially provide hepatocytes for treatment of end-stage liver disease. Additionally,hepatocyte-like cells generated from human pluripotent stem cells could serve as platforms for drug discovery,determination of pharmaceutical-induced hepatotoxicity,and evaluation of idiosyncratic drug-drug interactions. Here,we describe a step-wise protocol previously developed in our laboratory that facilitates the highly efficient and reproducible differentiation of human pluripotent stem cells into hepatocyte-like cells. Our protocol uses defined culture conditions and closely recapitulates key developmental events that are found to occur during hepatogenesis. View Publication

Radiotherapy represents the most effective nonsurgical treatments for gliomas. However,gliomas are highly radioresistant and recurrence is nearly universal. Results from our laboratory and other groups suggest that cancer stem cells contribute to radioresistance in gliomas and breast cancers. The Notch pathway is critically implicated in stem cell fate determination and cancer. In this study,we show that inhibition of Notch pathway with gamma-secretase inhibitors (GSIs) renders the glioma stem cells more sensitive to radiation at clinically relevant doses. GSIs enhance radiation-induced cell death and impair clonogenic survival of glioma stem cells but not non-stem glioma cells. Expression of the constitutively active intracellular domains of Notch1 or Notch2 protect glioma stem cells against radiation. Notch inhibition with GSIs does not alter the DNA damage response of glioma stem cells after radiation but rather reduces Akt activity and Mcl-1 levels. Finally,knockdown of Notch1 or Notch2 sensitizes glioma stem cells to radiation and impairs xenograft tumor formation. Taken together,our results suggest a critical role of Notch signaling to regulate radioresistance of glioma stem cells. Inhibition of Notch signaling holds promise to improve the efficiency of current radiotherapy in glioma treatment. View Publication