Generation of Functional Human 3D Cortico-Motor Assembloids.

Neurons in the cerebral cortex connect through descending pathways to hindbrain and spinal cord to activate muscle and generate movement. Although components of this pathway have been previously generated and studied in vitro, the assembly of this multi-synaptic circuit has not yet been achieved with human cells. Here, we derive organoids resembling the cerebral cortex or the hindbrain/spinal cord and assemble them with human skeletal muscle spheroids to generate 3D cortico-motor assembloids. Using rabies tracing, calcium imaging, and patch-clamp recordings, we show that corticofugal neurons project and connect with spinal spheroids, while spinal-derived motor neurons connect with muscle. Glutamate uncaging or optogenetic stimulation of cortical spheroids triggers robust contraction of 3D muscle, and assembloids are morphologically and functionally intact for up to 10 weeks post-fusion. Together, this system highlights the remarkable self-assembly capacity of 3D cultures to form functional circuits that could be used to understand development and disease.

Advancing models of neural development with biomaterials.

Human pluripotent stem cells have emerged as a promising in vitro model system for studying the brain. Two-dimensional and three-dimensional cell culture paradigms have provided valuable insights into the pathogenesis of neuropsychiatric disorders, but they remain limited in their capacity to model certain features of human neural development. Specifically, current models do not efficiently incorporate extracellular matrix-derived biochemical and biophysical cues, facilitate multicellular spatio-temporal patterning, or achieve advanced functional maturation. Engineered biomaterials have the capacity to create increasingly biomimetic neural microenvironments, yet further refinement is needed before these approaches are widely implemented. This Review therefore highlights how continued progression and increased integration of engineered biomaterials may be well poised to address intractable challenges in recapitulating human neural development.

Human assembloids.

Deconstructing and then reconstructing developmental processes ex vivo is crucial to understanding how organs assemble and how physiology can be disrupted in disease. Human 3D stem cell-derived systems, such as organoids, have facilitated this pursuit; however, they often do not capture inter-tissue or inter-lineage cellular interactions that give rise to emergent tissue properties during development. Assembloids are self-organizing 3D cellular systems that result from the integration of multiple organoids or the combination of organoids with missing cell types or primary tissue explants. Here, we outline the concept and types of assembloids and present their applications for studying the nervous system and other tissues. We describe tools that are used to probe and manipulate assembloids and delineate current challenges and the potential for this new approach to interrogate development and disease.

Association of PARP inhibitor treatment on the prevalence and progression of clonal hematopoiesis in patients with advanced prostate cancer.

BACKGROUND: Poly ADP-ribose polymerase (PARP) inhibitors are approved for the treatment of some men with advanced prostate cancer. Rare but serious side effects include myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The impact of PARP inhibitors on clonal hematopoiesis (CH), a potential precursor lesion associated with MDS and AML, is incompletely understood in prostate cancer. We hypothesized that PARP inhibitors would increase CH prevalence and abundance. METHODS: We prospectively enrolled participants with advanced prostate cancer treated with PARP inhibitors. The presence of CH was assessed from leukocytes using an ultra-deep error-corrected dual unique molecular identifiers sequencing method targeting 49 genes most commonly mutated in CH and myeloid malignancies. Variant allele frequencies (VAF) of ≥0.5% were considered clinically significant. Blood samples were collected before and after PARP inhibitor treatment. RESULTS: Ten men were enrolled; mean age of 67 years. Six patients had Gleason 7 disease, and four had Gleason ≥8 disease at diagnosis. Nine had localized disease at diagnosis, and eight had prior treatment with radiation. The mean time between pre- and post-treatment blood samples was 11 months (range 2.6-31 months). Six patients (60%) had CH identified prior to PARP inhibitor treatment, three with multiple clones. Of 11 CH clones identified in follow-up, 5 (45%) appeared or increased after treatment. DNMT3A, TET2, and PPM1D were the most common CH alterations observed. The largest post-treatment increase involved the PPM1D gene. CONCLUSION: CH alterations are frequently found after treatment with PARP inhibitors in patients with prostate cancer and this may be one mechanism by which PARP inhibitors lead to increased risk of MDS/AML.

Focus on organoids: cooperation and interconnection with extracellular vesicles - Is this the future of in vitro modeling?

Organoids are simplified in vitro model systems of organs that are used for modeling tissue development and disease, drug screening, cell therapy, and personalized medicine. Despite considerable success in the design of organoids, challenges remain in achieving real-life applications. Organoids serve as unique and organized groups of micro physiological systems that are capable of self-renewal and self-organization. Moreover, they exhibit similar organ functionality(ies) as that of tissue(s) of origin. Organoids can be designed from adult stem cells, induced pluripotent stem cells, or embryonic stem cells. They consist of most of the important cell types of the desired tissue/organ along with the topology and cell-cell interactions that are highly similar to those of an in vivo tissue/organ. Organoids have gained interest in human biomedical research, as they demonstrate high promise for use in basic, translational, and applied research. As in vitro models, organoids offer significant opportunities for reducing the reliance and use of experimental animals. In this review, we will provide an overview of organoids, as well as those intercellular communications mediated by extracellular vesicles (EVs), and discuss the importance of organoids in modeling a tumor immune microenvironment (TIME). Organoids can also be exploited to develop a better understanding of intercellular communications mediated by EVs. Also, organoids are useful in mimicking TIME, thereby offering a better-controlled environment for studying various associated biological processes and immune cell types involved in tumor immunity, such as T-cells, macrophages, dendritic cells, and myeloid-derived suppressor cells, among others.

Assembly of functionally integrated human forebrain spheroids.

The development of the nervous system involves a coordinated succession of events including the migration of GABAergic (γ-aminobutyric-acid-releasing) neurons from ventral to dorsal forebrain and their integration into cortical circuits. However, these interregional interactions have not yet been modelled with human cells. Here we generate three-dimensional spheroids from human pluripotent stem cells that resemble either the dorsal or ventral forebrain and contain cortical glutamatergic or GABAergic neurons. These subdomain-specific forebrain spheroids can be assembled in vitro to recapitulate the saltatory migration of interneurons observed in the fetal forebrain. Using this system, we find that in Timothy syndrome-a neurodevelopmental disorder that is caused by mutations in the CaV1.2 calcium channel-interneurons display abnormal migratory saltations. We also show that after migration, interneurons functionally integrate with glutamatergic neurons to form a microphysiological system. We anticipate that this approach will be useful for studying neural development and disease, and for deriving spheroids that resemble other brain regions to assemble circuits in vitro.

Generating human neurons in vitro and using them to understand neuropsychiatric disease.

Recent advances in cell reprogramming enable investigators to generate pluripotent stem cells from somatic cells. These induced pluripotent cells can subsequently be differentiated into any cell type, making it possible for the first time to obtain functional human neurons in the lab from control subjects and patients with psychiatric disorders. In this review, we survey the progress made in generating various neuronal subtypes in vitro, with special emphasis on the characterization of these neurons and the identification of unique features of human brain development in a dish. We also discuss efforts to uncover neuronal phenotypes from patients with psychiatric disease and prospects for the use of this platform for drug development.

Implications of TET2 in CAR-T Cell Activity and Target Response to CAR-T Cell Therapy: Lessons Learned from T Cells.

Chimeric antigen receptor T (CAR-T) cell therapy is a recent therapeutic addition to the field of oncology, the first one approved as represented by tisagenlecleucel followed shortly by approval of axicabtagene ciloleucel. Because this product is derived from T cells, there are several lessons that can be learned from T-cell biology to better understand CAR-T cells. Thus, in this review we discuss the effects that TET2 can have on T cells, macrophages interacting with T cells, and nonimmune cells. In T cells, TET2 mutations have been frequently shown to be associated with FOXP3 expression reduction and instability, which leads to reduction in T regulatory (Treg) cells and increases in T-helper (Th)1 and Th17 cells. This alteration in T-cell polarization balance leads to both an enhanced antitumor activity and an increased probability of autoimmune diseases. In the case of macrophages, TET2 has a similar role, as its reduced activity is associated with an M1 signature but its overexpression is associated with an M2 signature. In nonimmune cells, the role of TET2 is opposite its role in immune cells. Specifically, the reduction in TET2 activity is associated with a decreased immune response both in malignancies and in autoimmune diseases. In the current review, we discuss the role that TET2 plays in T-cell activity and in nonimmune cells in relation to T cells.

Targeting Cell Death Mechanism Specifically in Triple Negative Breast Cancer Cell Lines.

Triple negative breast cancer (TNBC) is currently associated with a lack of treatment options. Arsenic derivatives have shown antitumoral activity both in vitro and in vivo; however, their mode of action is not completely understood. In this work we evaluate the response to arsenate of the double positive MCF-7 breast cancer cell line as well as of two different TNBC cell lines, Hs578T and MDA-MB-231. Multimodal experiments were conducted to this end, using functional assays and microarrays. Arsenate was found to induce cytoskeletal alteration, autophagy and apoptosis in TNBC cells, and moderate effects in MCF-7 cells. Gene expression analysis showed that the TNBC cell lines' response to arsenate was more prominent in the G2M checkpoint, autophagy and apoptosis compared to the Human Mammary Epithelial Cells (HMEC) and MCF-7 cell lines. We confirmed the downregulation of anti-apoptotic genes (MCL1, BCL2, TGFß1 and CCND1) by qRT-PCR, and on the protein level, for TGFß2, by ELISA. Insight into the mode of action of arsenate in TNBC cell lines it is provided, and we concluded that TNBC and non-TNBC cell lines reacted differently to arsenate treatment in this particular experimental setup. We suggest the future research of arsenate as a treatment strategy against TNBC.

Azacytidine plus olaparib for relapsed acute myeloid leukaemia, ineligible for intensive chemotherapy, diagnosed with a synchronous malignancy.

Patients with relapsed/refractory acute myeloid leukaemia (AML), ineligible for intensive chemotherapy and allogeneic stem cell transplantation, have a dismal prognosis. For such cases, hypomethylating agents are a viable alternative, but with limited success. Combination chemotherapy using a hypomethylating agent plus another drug would potentially bring forward new alternatives. In the present manuscript, we present the cell and molecular background for a clinical scenario of a 44-year-old patient, diagnosed with high-grade serous ovarian carcinoma, diagnosed, and treated with a synchronous AML. Once the ovarian carcinoma relapsed, maintenance treatment with olaparib was initiated. Concomitantly, the bone marrow aspirate showed 30% myeloid blasts, consistent with a relapse of the underlying haematological disease. Azacytidine 75 mg/m2 treatment was started for seven days. The patient was administered two regimens of azacytidine monotherapy, additional to the olaparib-based maintenance therapy. After the second treatment, the patient presented with leucocytosis and 94% myeloid blasts on the bone marrow smear. Later, the patient unfortunately died. Following this clinical scenario, we reproduced in vitro the combination chemotherapy of azacytidine plus olaparib, to accurately assess the basic mechanisms of leukaemia progression, and resistance to treatment. Combination chemotherapy with drugs that theoretically target both malignancies might potentially be of use. Still, further research, both pre-clinical and clinical, is needed to accurately assess such cases.

Transforming growth factor ß-mediated micromechanics modulates disease progression in primary myelofibrosis.

Primary myelofibrosis (PMF) is a Ph-negative myeloproliferative neoplasm (MPN), characterized by advanced bone marrow fibrosis and extramedullary haematopoiesis. The bone marrow fibrosis results from excessive proliferation of fibroblasts that are influenced by several cytokines in the microenvironment, of which transforming growth factor-ß (TGF-ß) is the most important. Micromechanics related to the niche has not yet been elucidated. In this study, we hypothesized that mechanical stress modulates TGF-ß signalling leading to further activation and subsequent proliferation and invasion of bone marrow fibroblasts, thus showing the important role of micromechanics in the development and progression of PMF, both in the bone marrow and in extramedullary sites. Using three PMF-derived fibroblast cell lines and transforming growth factor-ß receptor (TGFBR) 1 and 2 knock-down PMF-derived fibroblasts, we showed that mechanical stress does stimulate the collagen synthesis by the fibroblasts in patients with myelofibrosis, through the TGFBR1, which however seems to be activated through alternative pathways, other than TGFBR2.

MicroRNA-155-5p Plays a Critical Role in Transient Leukemia of Down Syndrome by Targeting Tumor Necrosis Factor Receptor Superfamily Members.

BACKGROUND/AIMS: Down syndrome associated disorders are caused by a complex genetic context where trisomy 21 is a central component in relation to other changes involving epigenetic regulators and signaling molecules. This unique genetic context is responsible for the predisposition of people with Down syndrome to acute leukemia. Although, the research in this field has discovered some important pathogenic keys, the exact mechanism of this predisposition is not known. METHODS: In this study we applied functional enrichment analysis to evaluate the interactions between genes localized on chromosome 21, genes already identify as having a key role in acute leukemia of Down syndrome, miRNAs and signaling pathways implicated in cancer and cell development and found that miR-155 has a high impact in genes present on chromosome 21. Forward, we performed next generation sequencing on DNA samples from a cohort of patients diagnosed with acute leukemia of Down syndrome and in vitro functional assay using a CMK-86 cell line, transfected with either mimic or inhibitor of the microRNA-155-5p. RESULTS: Our results show that the epigenetic alteration of the TNF superfamily receptors in Down syndrome, which can be correlated to microRNA-155-5p aberrant activity, may play an important role in cell signaling and thus be linked to acute myeloid leukemia. CONCLUSION: Some genes, already shown to be mutated in AML-DS, are potential targets for miR-155. Our results show that the epigenetic alteration of the TNF superfamily receptors in Down syndrome may play an important role in cell signaling and thus be linked to acute myeloid leukemia.

Mental Fatigue Evaluation of Surgical Teams during a Regular Workday in a High-Volume Tertiary Healthcare Center.

INTRODUCTION: Considering the complex set of manual and psychological tasks a surgeon has to perform during the day, it is very important to assess the surgeon's fatigability, reaction time, attention, and memory. OBJECTIVE: Here, we wanted to determine the mental fatigue status of surgeons and how their abilities are affected through a regular workday. METHODS: We included 3 senior urologists and 6 urology residents. In a set period of time, we assessed their fatigue through self-assessed fatigue, Samn-Perelli score, and Karolinska sleepiness scale score. Further, reaction time, attention, and memory correlated with the number of the operations in the day, and total number of operations in that day were assessed. RESULTS: As the number of tasks increases, and as the surgeons advance to the end of the workday, they become more fatigued, reaction time ultimately increases, and attention and memory become slightly altered. CONCLUSIONS: Complications resulting from the fatigue of surgeons could be serious. Their performance status and skills decrease as they perform more tasks or advance through the day.

Nondestructive nanostraw intracellular sampling for longitudinal cell monitoring.

Here, we report a method for time-resolved, longitudinal extraction and quantitative measurement of intracellular proteins and mRNA from a variety of cell types. Cytosolic contents were repeatedly sampled from the same cell or population of cells for more than 5 d through a cell-culture substrate, incorporating hollow 150-nm-diameter nanostraws (NS) within a defined sampling region. Once extracted, the cellular contents were analyzed with conventional methods, including fluorescence, enzymatic assays (ELISA), and quantitative real-time PCR. This process was nondestructive with >95% cell viability after sampling, enabling long-term analysis. It is important to note that the measured quantities from the cell extract were found to constitute a statistically significant representation of the actual contents within the cells. Of 48 mRNA sequences analyzed from a population of cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs), 41 were accurately quantified. The NS platform samples from a select subpopulation of cells within a larger culture, allowing native cell-to-cell contact and communication even during vigorous activity such as cardiomyocyte beating. This platform was applied both to cell lines and to primary cells, including CHO cells, hiPSC-CMs, and human astrocytes derived in 3D cortical spheroids. By tracking the same cell or group of cells over time, this method offers an avenue to understand dynamic cell behavior, including processes such as induced pluripotency and differentiation.

Engineering a Genetically Encoded Magnetic Protein Crystal.

Magnetogenetics is a new field that leverages genetically encoded proteins and protein assemblies that are sensitive to magnetic fields to study and manipulate cell behavior. Theoretical studies show that many proposed magnetogenetic proteins do not contain enough iron to generate substantial magnetic forces. Here, we have engineered a genetically encoded ferritin-containing protein crystal that grows inside mammalian cells. Each of these crystals contains more than 10 million ferritin subunits and is capable of mineralizing substantial amounts of iron. When isolated from cells and loaded with iron in vitro, these crystals generate magnetic forces that are 9 orders of magnitude larger than the forces from the single ferritin cages used in previous studies. These protein crystals are attracted to an applied magnetic field and move toward magnets even when internalized into cells. While additional studies are needed to realize the full potential of magnetogenetics, these results demonstrate the feasibility of engineering protein assemblies for magnetic sensing.

TET2/IDH1/2/WT1 and NPM1 Mutations Influence the RUNX1 Expression Correlations in Acute Myeloid Leukemia.

Background and objectives: Mutational analysis has led to a better understanding of acute myeloid leukemia (AML) biology and to an improvement in clinical management. Some of the most important mutations that affect AML biology are represented by mutations in genes related to methylation, more specifically: TET2, IDH1, IDH2 and WT1. Because it has been shown in numerous studies that mutations in these genes lead to similar expression profiles and phenotypes in AML, we decided to assess if mutations in any of those genes interact with other genes important for AML. Materials and Methods: We downloaded the clinical data, mutational profile and expression profile from the TCGA LAML dataset via cBioPortal. Data were analyzed using classical statistical methods and functional enrichment analysis software represented by STRING and GOrilla. Results: The first step we took was to assess the 196 AML cases that had a mutational profile available and observe the mutations that overlapped with TET2/IDH1/2/WT1 mutations. We observed that RUNX1 mutations significantly overlap with TET2/IDH1/2/WT1 mutations. Because of this, we decided to further investigate the role of RUNX1 mutations in modulating the level of RUNX1 mRNA and observed that RUNX1 mutant cases presented higher levels of RUNX1 mRNA. Because there were only 16 cases of RUNX1 mutant samples and that mutations in this gene determined a change in mRNA expression, we further observed the correlation between RUNX1 and other mRNAs in subgroups regarding the presence of hypermethylating mutations and NPM1. Here, we observed that both TET2/IDH1/2/WT1 and NPM1 mutations increase the number of genes negatively correlated with RUNX1 and that these genes were significantly linked to myeloid activation. Conclusions: In the current study, we have shown that NPM1 and TET2/IDH1/2/WT1 mutations increase the number of negative correlations of RUNX1 with other transcripts involved in myeloid differentiation.

Topical Corticosteroids a Viable Solution for Oral Graft Versus Host Disease? A Systematic Insight on Randomized Clinical Trials.

Background and Objectives: This research attempts to provide a clear view of the literature on randomized clinical trials (RCTs) concerning the efficacy of topical dexamethasone, clobetasol and budesonide in oral graft versus host disease (GVHD). Materials and Methods: An electronic search of the PubMed, Web of Science and Scopus databases was carried out for eligible RCTs. Studies were included if they had adult patients with oral GVHD treatment with topical corticosteroids, and if the RCT study was published in English. The Cochrane Risk of Bias tool was used to assess the quality of these studies. Overall, three RCTs were included (an Open, Randomized, Multicenter Trial; a Randomized Double-Blind Clinical Trial; and an Open-Label Phase II Randomized Trial). Results: The trials involved 76 patients, of which 44 patients received topical dexamethasone, 14 patients received topical clobetasol and 18 patients received topical budesonide. Topical agents were most frequently used when oral tissues were the sole site of involvement. It appears that the best overall response is present for budesonide with no difference between the four arms, followed by clobetasol, and then by dexamethasone. The limitation of the current study is mainly represented by the fact that overall response was derived in two of the studies from other parameters. Moreover, both budesonide and clobetasol were used in only one study each, while two assessed dexamethasone. Conclusions: Based on the clinical trials, all three agents seem to be effective in treating oral GVHD and had a satisfactory safety profile. There is still a need for assessing high quality RCTs to assess the efficacy of these therapies on a larger cohort.

Transient leukemia of Down syndrome.

Childhood leukemia is mostly a "developmental accident" during fetal hematopoiesis and may require multiple prenatal and postnatal "hits". The World Health Organization defines transient leukemia of Down syndrome (DS) as increased peripheral blood blasts in neonates with DS and classifies this type of leukemia as a separate entity. Although it was shown that DS predisposes children to myeloid leukemia, neither the nature of the predisposition nor the associated genetic lesions have been defined. Acute myeloid leukemia of DS is a unique disease characterized by a long pre-leukemic, myelodysplastic phase, unusual chromosomal findings and a high cure rate. In the present manuscript, we present a comprehensive review of the literature about clinical and biological findings of transient leukemia of DS (TL-DS) and link them with the genetic discoveries in the field. We address the manuscript to the pediatric generalist and especially to the next generation of pediatric hematologists.