EBF1-deficient bone marrow stroma elicits persistent changes in HSC potential

Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here, we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFRα+Sca1+ (PαS) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition, chromatin structure and gene expression profiles, including the reduced expression of adhesion-related genes. Functionally, the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs, leading to reduced quiescence and diminished myeloid output. Most notably, HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus, genetic alterations in the BM niche lead to long-term functional changes of HSCs

The unbearable lightness of bone marrow homeostasis

The anatomical and functional dimensions of bone marrow topography have been at the forefront of modern bone and immunological research for many years and remain a source of complexity and perplexity due to the multitude of microhabitats within this microenvironment. In fact, research has uncovered fascinating functional aspects of bone marrow residents, and the bone marrow niche has been identified as the foremost reservoir of a variety of cells including hematopoietic, skeletal and endothelial stem/progenitor cells. The physical interactions of the marrow residents, combined with the release of cytokines and growth factors, organize well-defined operative compartments, which preserve bone and immune cell homeostasis. In a simplistic view, both the hematopoietic and bone marrow stromal (mesenchymal) stem/progenitor cell populations dwell at the interface between the endosteum and the bone marrow area (endosteal niche) and in the perivascular space (vascular niche). Indeed, the tantalizing hypothesis of bone marrow regulatory dependency on these niches is supported by current research insofar as the increase in the number of osteoblasts results in a concomitant increase in the hematopoietic population, indicating that the osteoblasts and the endosteal niche are key components of HSC maintenance. On the other hand, impaired function of the vascular niche compromises the endosteal niche's ability to support hematopoiesis. These fascinating discoveries indicate that there are strong ties between bone marrow inhabitants within the confines of the bone marrow itself. When these ties fail, niche-niche communication suffers and results in reduced bone formation, enfeebled hematopoiesis and unrestrained HSC migration through blood circulation. This study focused on the extraordinary homeostatic equilibrium and function of both bone and immune cells within the spatially defined microenvironment of bone marrow. But how important is the anatomically outlined scenery in which the bone marrow entity supports and hosts the hematopoietic elements

Patchy Amphiphilic Dendrimers Bind Adenovirus and Control Its Host Interactions and in Vivo Distribution

The surface of proteins is heterogeneous with sophisticated but precise hydrophobic and hydrophilic patches, which is essential for their diverse biological functions. To emulate such distinct surface patterns on macromolecules, we used rigid spherical synthetic dendrimers (polyphenylene dendrimers) to provide controlled amphiphilic surface patches with molecular precision. We identified an,. I optimal spatial arrangement of these patches on certain dendrimers that enabled their interaction with human adenovirus 5 (Ads). Patchy dendrimers bound to the surface of Ads formed a synthetic polymer corona that greatly altered various host interactions of Ads as well as in vivo distribution. The dendrimer corona (1) improved the ability of Ad5-derived gene transfer vectors to transduce cells deficient for the primary Ad5 cell membrane receptor and (2) modulated the binding of Ads to blood coagulation factor X, one of the most critical virus host interactions in the bloodstream. It significantly enhanced the transduction efficiency of Ad5 while also protecting it from neutralization by natural antibodies and the complement system in human whole blood. Ads with a synthetic dendrimer corona revealed profoundly altered in vivo distribution, improved transduction of heart, and dampened vector sequestration by liver and spleen. We propose the design of bioactive polymers that bind protein surfaces solely based on their amphiphilic surface patches and protect against a naturally occurring protein corona, which is highly attractive to improve Ad5-based in vivo gene therapy applications

Engineered Tumor-Targeted T Cells Mediate Enhanced Anti-Tumor Efficacy Both Directly and through Activation of the Endogenous Immune System.

Chimeric antigen receptor (CAR) T cell therapy has proven clinically beneficial against B cell acute lymphoblastic leukemia and non-Hodgkin's lymphoma. However, suboptimal clinical outcomes have been associated with decreased expansion and persistence of adoptively transferred CAR T cells, antigen-negative relapses, and impairment by an immunosuppressive tumor microenvironment. Improvements in CAR T cell design are required to enhance clinical efficacy, as well as broaden the applicability of this technology. Here, we demonstrate that interleukin-18 (IL-18)-secreting CAR T cells exhibit enhanced in vivo expansion and persistence and significantly increase long-term survival in syngeneic mouse models of both hematological and solid malignancies. In addition, we demonstrate that IL-18-secreting CAR T cells are capable of modulating the tumor microenvironment, as well as enhancing an effective endogenous anti-tumor immune response. IL-18-secreting CAR T cells represent a promising strategy to enhance the clinical outcomes of adoptive T cell therapy

In Vivo Generation of Engraftable Murine Hematopoietic Stem Cells by Gfi1b, c-Fos, and Gata2 Overexpression within Teratoma.

Generation of hematopoietic stem cells (HSCs) from pluripotent stem cells (PSCs) could potentially provide unlimited HSCs for clinical transplantation, a curative treatment for numerous blood diseases. However, to date, bona fide HSC generation has been largely unsuccessful in vitro. We have previously described proof of concept for in vivo HSC generation from PSCs via teratoma formation. However, our first-generation system was complex and the output low. Here, we further optimize this technology and demonstrate the following: (1) simplified HSC generation using transcription factor overexpression; (2) improved HSC output using c-Kit-deficient host mice, and (3) that teratomas can be transplanted and cryopreserved. We demonstrate that overexpression of Gfi1b, c-Fos, and Gata2, previously reported to transdifferentiate fibroblasts into hematopoietic progenitors in vitro, can induce long-term HSC formation in vivo. Our in vivo system provides a useful platform to investigate new strategies and re-evaluate existing strategies to generate HSCs and study HSC development

Biphenotypic Sinonasal Sarcoma-Case Report and Review of Clinicopathological Features and Diagnostic Modalities.

Background Biphenotypic sinonasal sarcoma is a recently described malignancy showing dual differentiation with both myogenic and neural elements. Due to its histologic similarities to other sinonasal malignancies, it is a diagnostic challenge. Objective The main purpose of this article is to report a case of biphenotypic sinonasal sarcoma and to consolidate data and provide a comprehensive review regarding pathological differences between biphenotypic sarcoma and other sinonasal malignancies and diagnostic modalities used for biphenotypic sarcoma. Material and Methods A systematic review of all cases of biphenotypic sinonasal sarcoma was performed using electronic databases (PubMed and Medline). Data collected included age, gender, symptoms, sub-site of origin, immunophenotyping, metastasis, recurrence, treatment, duration of follow-up, and survival outcomes. Results Ninety-five cases of biphenotypic sarcoma were found with mean age at diagnosis of 52.36 years (range, 24-87 years). Female to male ratio was 2.27:1. Extra-sinonasal extension was present in 28%. Immunophenotyping revealed that S-100 and SMA (smooth muscle actin) were consistently positive, while SOX-10 was consistently negative. PAX3-MAML3 fusion [t (2; 4) (q35; q31.1)] was the most common genetic rearrangement. Surgical excision with or without adjuvant radiotherapy was the most frequent treatment modality used. Recurrence was observed in 32% of cases with follow-up. None of the cases reported metastasis. Three patients had died at the time of publication that included one case with intracranial extension. Conclusion Biphenotypic sarcoma is distinct sinonasal malignancy with unique clinicopathological features. Testing involving a battery of myogenic and neural immunomarkers is essential for diagnostic confirmation and is a clinically useful endeavor when clinical suspicion is high. © 2019 Georg Thieme Verlag KG Stuttgart. New York

Rejection of Experimental Hodgkins Lymphoma by T-cells Engineered with a CD19 Chimeric Antigen Receptor

T cells engineered to express chimeric receptors combining an external antibody binding domain with the CD3ζ T cell receptor (TCR) internal domain for triggering cell activation are being used for immunotherapeutic targeting of tumour cells in a non-HLA restricted manner. In this study we transduced T cells with a CD19-cTCR construct containing a truncated CD34 gene (tCD24) marker and used these to target the B cell antigen CD19 on the surface of a Hodgkin’s lymphoma (HL) cell line (L591) both in vitro and in vivo. Levels of tCD34 expression in transduced peripheral blood mononuclear cells ranged from 6-20% and this was increased to 82% after selection for trasnduced tCD34+ cells. In vitro cytotoxicity testing on a CD19+ HL cell line (L591) showed specific cell lysis initiated by the CD19-cTCR transduced PBMCs. In tumour prevention experiments severe combined immunodeficient (SCID) mice were inoculated with L591 HL cells subcutaneously (sc), and simultaneously inoculated with transduced CD19-cTCR T cells either sc or intravenously (iv). None of the 6 mice which received CD19-cTCR transduced T cells sc developed tumours compared to 4/6 (67%) iv inoculated and 17/22 (77%) un-inoculated controls (p=0.001). In tumour treatment experiments, transduced CD19-cTCR T cells were given iv to SCID mice 3-9 days after sc tumour formation. Whereas tumours progressed in all control uninoculated animals, complete tumour regression occurred with all treated mice surviving over 65 days (p=0.011). Time course experiments showed infiltrating CD19-cTCR transduced T cells (tCD34+) in tumour tissue at 11 and 18 days post inoculation, reaching a maximum of 41% of cells. These results suggest that CD19 could be a target for the immunotherapy of HL and that further preclinical studies are warranted

Study and determination of an optimum design for space utilized lithium doped solar cells Quarterly report

Recovery characteristics of electron irradiated, lithium doped, solar cell