Biology subjects

Baumann, N.

Publications and source records attributed to Baumann, N..

8 recordsLinked to original sources

bioRxiv2025

Retargeted adenoviruses for local IgA and CD47 blocker production as a novel cancer therapy

Despite advances in IgG-based cancer immunotherapy, challenges remain in effectively engaging innate immune responses against solid tumors. Here, IgA antibodies hold promise due to their ability to activate neutrophils and macrophages. We present a novel retargeted adenovirus-mediated approach that transforms cancer cells into "biofactories" for localized production of monomeric or dimeric IgA antibodies and a CD47 blocker to potentiate the effect of IgA antibodies. With our approach tumor cells effectively produced IgA antibodies against tumor antigens such as EGFR or EpCAM and a soluble SIRP-Fc fusion protein, which blocks the CD47-SIRP axis. In a perfused tumor-on-a-chip model, locally produced IgA triggered neutrophil- and macrophage-mediated tumor cell killing, further potentiated by SIRP-Fc co-production. In FcRI-transgenic, tumor-bearing mice, intratumoral adenoviral injection induced strong local IgA and SIRP-Fc expression, immune cell infiltration, and more than 50% tumor volume reduction after a single treatment. We found that dimeric IgA exerts stronger effects than monomeric IgA, which is of particular interest since dimeric IgA necessitates a local production approach. Together, these results demonstrate that adenovirus-mediated, tumor-restricted delivery of IgA antibodies and CD47 blockade effectively engages innate immune mechanisms, providing a promising new avenue to enhance cancer immunotherapy. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/686998v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@183dd88org.highwire.dtl.DTLVardef@452624org.highwire.dtl.DTLVardef@1cb10e8org.highwire.dtl.DTLVardef@c2fa85_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Myeloid cell-mediated killing of B-ALL by CD38 and CD20IgA antibody variants is enhanced by CD47/SIRPα interference

Enhancing myeloid effector cell recruitment may improve immunotherapy by monoclonal antibodies - including that against acute lymphoblastic leukemia (ALL). To assess expression of target antigens in B-ALL, we compared mRNA profiling of 559 patient leukemia samples across 18 molecular subtypes with that of representative cell lines. The latter served as target cells to compare human IgG1 or IgA2 variants against CD19, CD20 or CD38 in antibody-dependent cellular phagocytosis (ADCP) by macrophages and antibody-dependent cell-mediated cytotoxicity (ADCC) by polymorphonuclear leukocytes (PMN). Interestingly, antibodies against broadly expressed CD19 were negligibly effective in mediating ADCP or ADCC. Antibodies against CD20 or CD38, the former variably expressed across subtypes, triggered ADCP by macrophages both as IgG1 and IgA2. However, PMN mediated ADCC against CD20 or CD38 was only observed with IgA2 variants, but not with respective IgG1 antibodies. Blocking the myeloid checkpoint molecule CD47 with a CD47 antibody or a soluble SIRP-Fc fusion protein enhanced ADCP and ADCC by IgA2 antibodies. The binding site for SIRP on CD47 contains an N-terminal pyroglutamate (pGlu), whose formation is catalyzed by glutaminyl-peptide cyclotransferase like (QPCTL). The direct involvement of pGlu in CD47/SIRP interactions was shown by using engineered CD47 variants. Both CD47 and QPCTL were broadly expressed across BCP-ALL subtypes, indicating QPCTL inhibitors as additional therapeutic option. Importantly, the combination of anti-CD38 IgA2 and CD47 blockade was effective against xenografted B-ALL cells in human FcRI (CD89) transgenic (tg) NXG mice. Together, these studies support the combination of anti-CD38 IgA2 with CD47 interference to improve myeloid effector cell recruitment for immunotherapy of B-ALL. Data sharing statementRNA-Seq data from BCP-ALL patients and B cells from healthy donors are available in the European Genome-Phenome Archive (EGA) accession numbers EGAS00001006107 and EGAS00001007305, respectively. Mass spectrometry data of analyzed proteins will be made available after manuscript acceptance on PRIDE - PRoteomics IDEntifications Database. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=174 HEIGHT=200 SRC="FIGDIR/small/669665v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@15220daorg.highwire.dtl.DTLVardef@eace04org.highwire.dtl.DTLVardef@17b87daorg.highwire.dtl.DTLVardef@1142822_HPS_FORMAT_FIGEXP M_FIG C_FIG Key pointsO_LIIgG1 and IgA2 antibodies against CD38 or CD20 were effective in recruiting macrophages for ADCP, but only IgA2 triggered ADCC by PMN C_LIO_LIMyeloid effector cell activation was enhanced by interfering with the CD47/SIRP axis, especially when IgA2 antibodies were applied C_LI

cancer biology↗

bioRxiv2024

Cell-extrinsic controls over neocortical neuron fate and diversity

Cellular diversity in the neocortex emerges gradually during prenatal and postnatal development. While environmental interactions occur during this extended maturation period, the impact of extrinsic cues on determining the fate of distinct neuron types remains unknown. To address this question, we exposed developing neocortical cells to various environmental conditions and examined how this affects cell fate and diversity. Our developmental analyses reveal a hierarchical molecular program in which cell class-distinguishing features emerge first, followed by subclass- and type-related characteristics, with distinct developmental paces among cell populations. Environmental contribution was assessed in vivo, using genetically modified mice models in which position or innervation are altered, and in vitro using two-dimensional cultures. Acquisition of cellular identity and diversity remained stable across in vivo models. In contrast, in vitro glutamatergic neurons showed decreased expression of identity-defining genes, reduced diversity and alterations in canonical cortical connectivity. Cellular identity and diversity were restored towards in vivo values in organotypic slice cultures. These findings reveal cell population-specific responses to environmental conditions and highlight the role of extracellular context in shaping cell diversity in the maturing neocortex.

neuroscience↗

bioRxiv2023

Regional Differences in Progenitor Consumption Dynamics Shape Brain Growth during Development

Developing mammalian brains are characterized by disproportionate growth of the forebrain compared to other regions. How this localized expansion occurs is, however, largely unknown. To address this, we identified region-specific neurogenic patterns by creating a single-cell-resolution birthdate atlas of the mouse brain (https://www.neurobirth.org). We report that in forebrain regions, neurogenesis is sustained compared to the hindbrain, where neurogenesis is transient and limited to early brain development. Sustained forebrain neurogenesis reflects lengthened cell cycle and reduced consumptive divisions of ventricular zone progenitors, resulting in a preserved germinal cell pool. Using single-cell RNA sequencing, we identify functional molecular programs of ventricular zone progenitors that spatially and temporally regulate progenitor cycling properties, including through loss-of-function of the forebrain-enriched mitochondrial membrane protein Fam210b. These results reveal a parsimonious mechanism to locally regulate neuronal production, in which the time window during which progenitors generate cells is a critical determinant of region-specific brain expansion.

neuroscience↗

bioRxiv2023

Extracellular vesicle-mediated trafficking of developmental cues is altered during human brain disease

Cellular crosstalk is an essential process influenced by numerous factors including secreted vesicles that transfer nucleic acids, lipids, and proteins between cells. Extracellular vesicles (EVs) have been the center of many studies focusing on neuron-to-neuron communication, but the role of EVs in progenitor-to-neuron and -astrocyte communication and whether EVs display cell-type-specific features for cellular crosstalk during neurogenesis is unknown. Here, using human-derived cerebral organoids, neural progenitors, neurons, and astrocytes, we found that many proteins coded by genes associated with neurodevelopmental disorders are transported via EVs. Thus, we characterized the protein content of EVs and showed their cell type-specific dynamics and function during brain development. Changes in the physiological crosstalk between cells can lead to neurodevelopmental disorders. EVs from patients with epilepsy were found altered in composition and function. Alterations in the intracellular and extracellular compartments highlighted a clear dysregulation of protein trafficking. This study sheds new light on the biology of EVs during brain development and neurodevelopmental disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=185 SRC="FIGDIR/small/546646v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@1dad15aorg.highwire.dtl.DTLVardef@e699ccorg.highwire.dtl.DTLVardef@17b371borg.highwire.dtl.DTLVardef@5efa7b_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstract(left) EV uptake mechanism varies depending on the receiving cell type; NPCs transport neuron EVs (nEVs) and astrocyte EVs (aEVs) to the nucleus, astrocytes localize progenitor EVs (pEVs) to the cytoplasm, and neurons retain pEVs and aEVs along the plasma membrane. (right) Cerebral organoids (COs) from progressive Myoclonus Epilepsy Type I (EPM1) patients release EVs lacking key proteins in neurodevelopment and proteins necessary for EV biogenesis and release. Illustration created using BioRender.

developmental biology↗

bioRxiv2023

Sox11 is enriched in myogenic progenitors but dispensable for development and regeneration of skeletal muscle.

Transcription factors (TFs) play key roles in regulating the differentiation and function of stem cells, including muscle satellite cells (MuSCs), a resident stem cell population responsible for postnatal regeneration of the skeletal muscle. Sox11 belongs to the Sry-related HMG-box (SOX) family of TFs that play diverse roles in stem cell behavior and tissue specification. Analysis of single-cell RNA-sequencing (scRNA-seq) datasets identify a specific enrichment of Sox11 mRNA in differentiating but not quiescent MuSCs. Consistent with the scRNA-seq data, Sox11 levels increase during differentiation of murine primary myoblasts in vitro. scRNA-seq data comparing muscle regeneration in young and old mice further demonstrate that Sox11 expression is reduced in aged MuSCs. Age-related decline of Sox11 expression is associated with reduced chromatin contacts within the topologically associated domains. Unexpectedly, Myod1Cre-driven deletion of Sox11 in embryonic myoblasts has no effects on muscle development and growth, resulting in apparently healthy muscles that regenerate normally. Pax7CreER or Rosa26CreER driven (MuSC-specific or global) deletion of Sox11 in adult mice similarly has no effects on MuSC differentiation or muscle regeneration. These results identify Sox11 as a novel myogenic differentiation marker with reduced expression in quiescent and aged MuSCs, but the specific function of Sox11 in myogenesis remain to be elucidated.

cell biology↗

bioRxiv2022

Extrinsic regulation of interneuron specification and migration

The imbalance between excitatory and inhibitory neurons in the human brain might lead to neurodevelopmental and neuropsychiatric disorders including cortical malformations, epilepsy, and autism spectrum disorders. We propose that the extracellular environment regulates interneuron differentiation and migration during development, ultimately affecting the excitatory/inhibitory balance. Using ventral cerebral organoids and dorso-ventral cerebral assembloids with mutations in the extracellular matrix gene LGALS3BP, we show that the composition of the extracellular environment regulates the molecular differentiation of neurons, resulting in alterations in migratory dynamics. To investigate how the extracellular environment affects neuronal specification and migration, we characterized the protein content of extracellular vesicles from cerebral organoids carrying a mutation in LGALS3BP, previously identified in individuals with cortical malformations and neuropsychiatric disorders. These results revealed differences in protein composition. Interestingly, proteins associated with cell-fate decision, neuronal migration and extracellular matrix composition were altered in mutant extracellular vesicles. Moreover, we show that treatment with extracellular vesicles changes the transcriptomic profile in neural progenitor cells. Our results indicate that neuronal molecular differentiation is regulated by factors released into the extracellular environment.

developmental biology↗

bioRxiv2018

Apical progenitors remain multipotent throughout corticalneurogenesis

The diverse subtypes of excitatory neurons that populate the neocortex are born from progenitors located in the ventricular zone (apical progenitors, APs). During corticogenesis, APs progress through successive temporal states to sequentially generate deep- followed by superficial-layer neurons directly or via the generation of intermediate progenitors (IPs). Yet little is known about the plasticity of AP temporal identity and whether individual progenitor subtypes remain multipotent throughout corticogenesis. To address this question, we used FlashTag (FT), a method to pulse-label and isolate APs in the mouse neocortex with high temporal resolution to fate-map neuronal progeny following heterochronic transplantation of APs into younger embryos. We find that unlike daughter IPs, which lose the ability to generate deep layer neurons when transplanted into a younger host, APs are temporally uncommitted and become molecularly respecified to generate normally earlier-born neuron types. These results indicate that APs are multipotent cells that are able to revert their temporal identity and re-enter past molecular and neurogenic states. AP fate progression thus occurs without detectable fate restriction during the neurogenic period of corticogenesis. These findings identify unforeseen cell-type specific differences in cortical progenitor fate plasticity, which could be exploited for neuroregenerative purposes.

neuroscience↗