Biology subjects

Bresciani, E.

Publications and source records attributed to Bresciani, E..

6 recordsLinked to original sources

bioRxiv2023

Organ specific microenvironmental MR1 expression in cutaneous melanoma

The microenvironment is an important regulator of intertumoral trafficking and activity of immune cells. Understanding how the immune system can be tailored to maintain anti-tumor killing responses in metastatic disease remains an important goal. Thus, immune mediated eradication of metastasis requires the consideration of organ specific microenvironmental cues. Using a xenograft model of melanoma metastasis in adult zebrafish, we perturbed the dynamic balance between the infiltrating immune cells in the metastatic setting using a suite of different transgenic zebrafish. We employed intravital imaging coupled with metabolism imaging (FLIM) to visualize and map the organ specific metabolism with near simultaneity in multiple metastatic lesions. Of all the MHC complexes examined for brain and skeletal metastases, we determined that there is an organ specific expression of mhc1uba (human ortholog, MR1) for both the melanoma cells and the resident and infiltrating immune cells. Specifically, immune clusters did not express mhc1uba in brain metastatic lesions in immune competent fish. Finally, the differential immune response drove organ specific metabolism where tumor glycolysis was increased in brain metastases compared to skeletal and parental lines as measured using fluorescence lifetime imaging microscopy (FLIM). As MR1 belongs to the MHC class I molecules and is a target of immunotherapeutic drugs, we believe that our data presents an opportunity to understand the relationship between organ specific tumor metabolism and drug efficacy in the metastatic setting.

cancer biology↗

bioRxiv2023

RUNX1 is required in granulocyte-monocyte progenitors to attenuate inflammatory cytokine production by neutrophils

The transcription factor RUNX1 is mutated in familial platelet disorder with associated myeloid malignancies (FPDMM) and in sporadic myelodysplastic syndrome and leukemia. RUNX1 regulates inflammation in multiple cell types. Here we show that RUNX1 is required in granulocyte-monocyte progenitors (GMPs) to restrict the inflammatory response of neutrophils to toll-like receptor 4 (TLR4) signaling. Loss of RUNX1 in GMPs increased the TLR4 coreceptor CD14 on neutrophils, which contributed to neutrophils increased inflammatory cytokine production in response to the TLR4 ligand lipopolysaccharide. RUNX1 loss increased the chromatin accessibility of retrotransposons in GMPs and neutrophils and induced a type I interferon signature characterized by enriched footprints for signal transducer and activator of transcription (STAT1::STAT2) and interferon regulatory factors (IRF) in opened chromatin, and increased expression of interferon-stimulated genes. The overproduction of inflammatory cytokines by neutrophils was reversed by inhibitors of type I IFN signaling. We conclude that RUNX1 restrains the chromatin accessibility of retrotransposons in GMPs and neutrophils, and that loss of RUNX1 increases proinflammatory cytokine production by elevating tonic type I interferon signaling.

developmental biology↗

bioRxiv2023

Genomic Landscape of Patients with Germline RUNX1 Variants and Familial Platelet Disorder with Myeloid Malignancies in a Natural History Study

Germline RUNX1 mutations lead to familial platelet disorder with associated myeloid malignancies (FPDMM), which is characterized by thrombocytopenia and a life-long risk (35-45%) of hematological malignancies. We recently launched a longitudinal natural history study for patients with FPDMM at the NIH Clinical Center. Among 29 families with research genomic data, 28 different germline RUNX1 variants were detected. Besides missense mutations enriched in Runt homology domain and loss-of-function mutations distributed throughout the gene, splice-region mutations and large deletions were detected in 6 and 7 families, respectively. In 24 of 54 (44.4%) non-malignant patients, somatic mutations were detected in at least one of the clonal hematopoiesis of indeterminate potential (CHIP) genes or acute myeloid leukemia (AML) driver genes. BCOR was the most frequently mutated gene (in 9 patients), and multiple BCOR mutations were identified in 4 patients. Mutations in 7 other CHIP or AML driver genes (DNMT3A, TET2, NRAS, SETBP1, SF3B1, KMT2C, and LRP1B) were also found in more than one non-malignant patient. Moreover, three unrelated patients (one with myeloid malignancy) carried somatic mutations in NFE2, which regulates erythroid and megakaryocytic differentiation. Sequential sequencing data from 19 patients demonstrated dynamic changes of somatic mutations over time, and stable clones were more frequently found in elderly patients. In summary, there are diverse types of germline RUNX1 mutations and high frequency of somatic mutations related to clonal hematopoiesis in patients with FPDMM. Monitoring dynamic changes of somatic mutations prospectively will benefit patients clinical management and reveal mechanisms for progression to myeloid malignancies. Key PointsO_LIComprehensive genomic profile of patients with FPDMM with germline RUNX1 mutations. C_LIO_LIRising clonal hematopoiesis related secondary mutations that may lead to myeloid malignancies. C_LI

genomics↗

bioRxiv2021

Redundant mechanisms driven independently by RUNX1 and GATA2 for hematopoietic development

RUNX1 is essential for the generation of hematopoietic stem cells (HSCs). Runx1 null mouse embryos lack definitive hematopoiesis and die in mid-gestation. However, even though zebrafish embryos with a runx1 W84X mutation have defects in early definitive hematopoiesis, some runx1W84X/W84X embryos can develop to fertile adults with blood cells of multi-lineages, raising the possibility that HSCs can emerge without RUNX1. Here, using three new zebrafish runx1-/- lines we uncovered the compensatory mechanism for runx1-independent hematopoiesis. We show that, in the absence of a functional runx1, a cd41-GFP+ population of hematopoietic precursors still emerge from the hemogenic endothelium and can colonize the hematopoietic tissues of the mutant embryos. Single-cell RNA sequencing of the cd41-GFP+ cells identified a set of runx1-/--specific signature genes during hematopoiesis. Significantly, gata2b, which normally acts upstream of runx1 for the generation of HSCs, was increased in the cd41-GFP+ cells in runx1- /- embryos. Interestingly, genetic inactivation of both gata2b and its paralog, gata2a, did not affect hematopoiesis. However, knocking out runx1 and any three of the four alleles of gata2a and gata2b abolished definitive hematopoiesis. Gata2 expression was also upregulated in hematopoietic cells in Runx1-/- mice, suggesting the compensatory mechanism is conserved. Our findings indicate that RUNX1 and GATA2 serve redundant roles for HSC production, acting as each others safeguard. Key pointsO_LIExistence of RUNX1-independent mechanisms for the generation of HSCs and the development of functional definitive hematopoietic cells C_LIO_LIGATA2 and RUNX1 functionally complement each other for their respective roles during hematopoiesis C_LI

genetics↗

bioRxiv2020

Hexarelin exerts neuroprotective and antioxidant effects against hydrogen peroxide-induced toxicity through the modulation of MAPK and PI3K/Akt patways in Neuro-2A cells.

Hexarelin, a synthetic hexapeptide, protects cardiac and skeletal muscles by inhibiting apoptosis, both in vitro and in vivo. Moreover, evidence suggests that hexarelin could have important neuroprotective bioactivity. Oxidative stress and the generation of free radicals has been implicated in the etiologies of several neurodegenerative diseases, including amyotrophic lateral sclerosis, Parkinsons disease, Alzheimers disease, Huntingtons disease and multiple sclerosis. In addition to direct oxidative stress, exogenous hydrogen peroxide (H2O2) can penetrate biological membranes and enhance the formation of other reactive oxygen species. The aim of this study was to examine the inhibitory influence of hexarelin on H2O2-induced apoptosis in Neuro-2A cells, a mouse neuroblastoma cell line. Our results indicate that H2O2 reduced the viability of Neuro-2A cells in a dose-related fashion. Furthermore, H2O2 induced significant changes in the morphology of Neuro-2A cells, reflected in the formation of apoptotic cell bodies, and an increase of nitric oxide (NO) production. Hexarelin effectively antagonized H2O2 oxidative damage to Neuro-2A cells as indicated by improved cell viability, normal morphology and reduced nitrite (NO2-) release. Hexarelin treatment of Neuro-2A cells also reduced mRNA levels of caspases-3 and -7 and those of the pro-apoptotic molecule Bax; by contrast, hexarelin treatment increased anti-apoptotic Bcl-2 mRNA levels. Hexarelin also reduced MAPKs phosphorylation induced by H2O2 and concurrently increased p-Akt protein expression. In conclusion, our results identify several neuroprotective and anti-apoptotic effects of hexarelin. These properties suggest that further investigation of hexarelin as a neuroprotective agent in an investigational and therapeutic context are merited.

pharmacology and toxicology↗

bioRxiv2020

A metabolic shift to glycolysis promotes zebrafish tail regeneration through TGF-β dependent dedifferentiation of notochord cells to form the blastema

Mammals are generally poor at tissue regeneration, in contrast, fish maintain a high capacity for regenerating complex tissues after injury. Using larval zebrafish, we show that tail amputation triggers an metabolic shift to glycolysis in cells surrounding the notochord as they reposition to the amputation site. Blocking glycolysis prevents the fin from regenerating after amputation due to the failure to form a normal, pluripotent blastema. We performed a time series of scRNA-sequencing on regenerating tails under normal conditions or in the absence of glycolysis. Strikingly, we detected a transient cell population in the single cell analysis that represents notochord sheath cells undergoing a TGF-{beta} dependent dedifferentiation and epithelium-to-mesenchyme transition to become pluripotent blastema cells. We further demonstrated that the metabolic switch to glycolysis is required for TGF-{beta} signaling and blocking either glycolysis or TGF-{beta} receptors results in aberrant blastema formation through the suppression of essential EMT mediators such as snai1.

developmental biology↗