Biology subjects

Zeltner, N.

Publications and source records attributed to Zeltner, N..

8 recordsLinked to original sources

bioRxiv2026

Autoantibodies from recovered Guillain-Barre syndrome patients exhibit altered effector functions that prevent subsequent neuron degeneration

Guillain-Barre syndrome (GBS) is an autoimmune polyneuropathy that is the leading cause of nonpoliovirus-associated acute flaccid paralysis worldwide. In most cases, GBS occurs following an infection, most commonly Campylobacter jejuni, through the induction of antibodies recognizing bacterial ganglioside-mimicking lipooligosaccharides that cross-react with human neuronal gangliosides. This post-infectious autoimmune cascade causes neuropathy, from which patients can recover as their anti-ganglioside antibody titers diminish and immunostimulation decreases. In this study, we find 10% of clinically confirmed GBS patients maintain high titers of circulating anti-ganglioside antibodies more than one decade after recovery. These antibodies no longer cause neuropathy compared to acute sera from the same patients using a human pluripotent stem cell-derived sensory neuron model with human complement. We found both IgG subclass and glycoform differences between paired acute and recovered GBS patient sera, including anti-inflammatory modifications on isolated anti-GM1 ganglioside antibodies. Together, these data suggest that patients with GBS select for non-pathogenic variants of autoantibodies that are no longer capable of damaging their neurons, but may still protect against C. jejuni infection.

immunology↗

bioRxiv2026

Organoid-like Functional Adrenal Gland Cortex Derived From Human Pluripotent Stem Cells

The adrenal cortex is a critical for life endocrine system. It manages metabolic homeostasis, electrolyte balance, stress response, and sex development. This is accomplished through the release of various steroids from a dynamically changing landscape of concentric cellular zones/layers. Adrenocortical dysfunction is implicated in pathologies ranging from adrenal insufficiency to hypertension. The in-depth investigation of adrenal gland biology, pathology and drug discovery has been hampered by a lack of human, experimentally tractable models. Particularly missing are models that recapitulate the cellular diversity of the adrenal cortex with representation of all fetal and adult cell layers and the capsule. Here, we employ human pluripotent stem cells (hPSCs) to generate cells of all three cortex zones alongside capsular cells in a single 2D platform. This platform mimics the cellular diversity expected from an organoid, yet it provides the simplicity of monolayer cultures, that are better suited for drug discovery and high-throughput settings. These cultures secrete zone-specific steroids (cortisol, aldosterone, and DHEA-S) and exhibit robust, physiologically relevant ACTH stimulation responses. Transcriptomic analysis revealed sequential acquisition of profiles consistent with adrenocortical development, zonation, and signaling programs consistent with zone maintenance. Our platform is validated by a literature meta-analysis that defines transcriptomic signatures for each human cortical cell type, spanning fetal and adult stages. Together, this novel adrenocortical platform enables investigation of adrenal development, disease mechanisms, and therapeutic strategies. Significance StatementWe describe a hPSC-based 2D differentiation strategy with the cell type complexity of an organoid and the technical simplicity necessary for high-throughput assays. The platform contains all cortical subtypes that mediate electrolyte regulation, stress response, sex development and self-maintenance of the tissue. This co-differentiation offers a unique opportunity to study human adrenal development, biology, pathology and enables drug discovery.

developmental biology↗

bioRxiv2025

A 3D Human Neuron-on-Chip Platform to Monitor Neuronal Injury Responses

Traumatic brain injury (TBI) is a major cause of neurological dysfunction and long-term neurodegeneration, yet the intrinsic neuronal contributions to TBI pathophysiology remain incompletely defined. Here, we present a novel Neuron-on-Chip microfluidic platform that can be used to mechanically injure mature human prefrontal cortex neurons (hPFCs) embedded in three-dimensional (3D) hydrogels, enabling the study of injury responses in pure neuronal cultures. We assessed real-time calcium dynamics across 13 metrics of single-cell and network activity, revealing a biphasic injury response: an early phase (0.5-24 hr) characterized by excitotoxicity, hyper-synchronized bursting, and network collapse; and a late phase (8 d) marked by sustained depolarization and structural remodeling. Secretome profiling uncovered progressive elevations in extracellular pT181 and total Tau from days 1 to 5 post-injury. Cytokine analyses identified early (24 hr) elevations in IP-10, IL-10, IFN2, and NCAM, and late increases (8 d) in CXCL9 and MPO, linking neuronal activity changes to stage-specific inflammatory signaling. Immunocytochemistry and immunoblotting confirmed temporally ordered upregulation of calpain-1 and active caspase-3 (days 1-3), phosphorylated Tau (AT8+, days 5-8), and neurofibrillary tangle-like Tau aggregates (NFT+, day 8). These findings establish our platform as a scalable microphysiological model for probing the dynamic cellular and molecular sequelae of neuronal response to injury, offering insights into neurodegeneration and opportunities for therapeutic discovery.

neuroscience↗

bioRxiv2024

Engineered CRISPR-Base Editors as a Permanent Treatment for Familial Dysautonomia

Familial dysautonomia (FD) is a fatal autosomal recessive sensory and autonomic neuropathy. FD is caused by a T-to-C point mutation in intron 20 of the Elongator acetyltransferase complex subunit 1 (ELP1) gene, which results in tissue-specific skipping of exon 20 to cause a premature termination codon and thus redues ELP1 protein levels. Here, we developed a CRISPR-Cas-based cytosine base editing strategy to permanently correct the disease-causing mutation and restore canonical mRNA splicing. Through systematic engineering of base editors and guide RNAs, we identified an optimal editor configuration capable of achieving up to 70% on-target correction in human cells and that restored ELP1 exon 20 inclusion. To enable in vivo delivery, a dual adeno-associated virus (AAV) intein-split base editor was delivered via intravenous injections in a humanized FD mouse mode, resulting in genetic correction and significantly increased ELP1 exon 20 inclusion in the brain and other tissues. In FD patient-derived iPSC-sympathetic neurons, we observed [~]10% correction efficiency but rescued disease-associated neuronal hyperactivity, demonstrating that partial correction can restore functional phenotypes. Genome-wide analyses revealed minimal off-target editing across multiple human cell types, supporting the specificity of this approach. Together, these findings establish a precise and permanent genome editing strategy for FD and supports the development of a one-time disease-modifying therapy for FD and highlights the therapeutic potential of base editing for splicing disorders.

bioengineering↗

bioRxiv2024

Laminin β4 is required for the development of human peripheral sensory neurons

The extracellular matrix (ECM) is a mixture of glycoproteins and fibrous proteins that provide the biophysical properties necessary to maintain cellular homeostasis. ECM integrity is of particular importance during development, where it allows proper migration and cellular differentiation. Laminins are ECM heterotrimeric proteins consisting of , {beta}, and {gamma} chains. There are five known chains, four {beta} chains, and three {gamma} chains. Thus, there are 60 potential combinations for laminin trimers, however only 16 laminin trimers have been identified to date. Furthermore, none of them contain laminin {beta}4 and its function is unknown. Here, we sought to characterize the role of LAMB4 (the gene encoding laminin {beta}4) during human embryonic development of the peripheral sensory nervous system. Using human pluripotent stem cells (hPSCs), we found that LAMB4 is expressed in the ectoderm in the early stages of sensory neuron (SN) specification. SNs, part of the peripheral nervous system, are specialized neurons that detect pain, temperature, and touch. Surprisingly, more than 20 million people in the US have some form of peripheral nerve damage (including SNs), however there are very few treatment options available. Learning about the biology of peripheral neurons will uncover potential new therapeutic targets, thus we focused on understanding the effects of LAMB4 in SNs. First, we knocked out LAMB4 in hPSCs, using CRISPR/Cas9, and found that loss of LAMB4 impairs the migration of the SN progenitors neural crest cells (NCCs) and harms SN development and survival. To assess if LAMB4 has clinical relevance, we studied the genetic disorder Familial Dysautonomia (FD), which specifically affects the peripheral nervous system. FD is caused by a mutation in ELP1 (a component of the Elongator complex) leading to developmental and degenerative defects in SNs. A previous report showed that patients with severe FD harbor additional single nucleotide variants in LAMB4. We found that these variants sharply downregulate the expression of LAMB4 and laminin {beta}4 levels in SNs differentiated from induced pluripotent stem cells (iPSCs) reprogramed from patients with severe FD. Moreover, a healthy ECM is sufficient to rescue the developmental phenotypes of FD, further confirming that ECM defects contribute significantly to the etiology of FD. Finally, we found that LAMB4/laminin {beta}4 is necessary for actin filament accumulation and it interacts with laminin 4 and laminin {gamma}3, forming the laminin-443, a previously unreported laminin trimer. Together, these results show that LAMB4 is a critical, but largely unknown gene required for SN development and survival.

cell biology↗

bioRxiv2023

Genipin Crosslinks the Extracellular Matrix to Rescue Developmental and Degenerative Defects, and Accelerates Regeneration of Peripheral Neurons

The peripheral nervous system (PNS) is essential for proper body function. A high percentage of the population suffer nerve degeneration or peripheral damage. For example, over 40% of patients with diabetes or undergoing chemotherapy develop peripheral neuropathies. Despite this, there are major gaps in the knowledge of human PNS development and therefore, there are no available treatments. Familial Dysautonomia (FD) is a devastating disorder that specifically affects the PNS making it an ideal model to study PNS dysfunction. FD is caused by a homozygous point mutation in ELP1 leading to developmental and degenerative defects in the sensory and autonomic lineages. We previously employed human pluripotent stem cells (hPSCs) to show that peripheral sensory neurons (SNs) are not generated efficiently and degenerate over time in FD. Here, we conducted a chemical screen to identify compounds able to rescue this SN differentiation inefficiency. We identified that genipin, a compound prescribed in Traditional Chinese Medicine for neurodegenerative disorders, restores neural crest and SN development in FD, both in the hPSC model and in a FD mouse model. Additionally, genipin prevented FD neuronal degeneration, suggesting that it could be offered to patients suffering from PNS neurodegenerative disorders. We found that genipin crosslinks the extracellular matrix, increases the stiffness of the ECM, reorganizes the actin cytoskeleton, and promotes transcription of YAP-dependent genes. Finally, we show that genipin enhances axon regeneration in an in vitro axotomy model in healthy sensory and sympathetic neurons (part of the PNS) and in prefrontal cortical neurons (part of the central nervous system, CNS). Our results suggest genipin can be used as a promising drug candidate for treatment of neurodevelopmental and neurodegenerative diseases, and as a enhancer of neuronal regeneration. One sentence summaryGenipin rescues the developmental and degenerative phenotypes of the peripheral neuropathy familial dysautonomia and enhances neuron regeneration after injury.

neuroscience↗

bioRxiv2021

Neural-specific alterations in glycosphingolipid biosynthesis and cell signaling associated with two human ganglioside GM3 Synthase Deficiency variants

GM3 Synthase Deficiency (GM3SD) is a neurodevelopmental disorder resulting from pathogenic variants in the ST3GAL5 gene, which encodes GM3 synthase, a glycosphingolipid (GSL)-specific sialyltransferase. This enzyme adds a single 3-linked sialic acid to the terminal galactose of lactosylceramide (LacCer) to produce the monosialylated ganglioside GM3. In turn, GM3 is extended by other glycosyltransferases to generate nearly all the complex gangliosides enriched in neural tissue. Pathogenic mechanisms that account for neural phenotypes associated with GM3SD are not known. To explore how loss of GM3 impacts neural-specific glycolipid glycosylation and cell signaling, GM3SD patient fibroblasts bearing one of two different ST3GAL5 variants were reprogrammed to induced pluripotent stem cells (iPSCs) and then differentiated to neural crest cells (NCCs). GM3 and GM3-derived gangliosides were undetectable in iPSCs and NCCs from both variants, while LacCer precursor levels were elevated compared to wildtype (WT). NCCs of both variants synthesized elevated levels of neutral lacto- and globo-series, as well as minor alternatively sialylated, GSLs compared to WT. Shifts in ceramide profiles associated with iPSC and NCC GSLs were also detected in GM3SD variants. Altered GSL profiles in the GM3SD cells were accompanied by dynamic changes in the cell surface proteome, protein O-GlcNAcylation, and receptor tyrosine kinase abundance. GM3SD cells also exhibited increased apoptosis and sensitivity to erlotnib, an inhibitor of epidermal growth factor receptor signaling. Pharmacologic inhibition of O-GlcNAcase increased protein O-GlcNAcylation and significantly rescued baseline and erlotnib-induced apoptosis. Collectively, these findings indicate broad effects on cell signaling during differentiation of GM3SD patient-derived iPSCs to NCCs. Thus, human GM3SD cells provide a novel platform to investigate structure/function relationships that connect GSL diversity to cell signaling, cell survival, and neural differentiation.

neuroscience↗

bioRxiv2020

Recurrent chromosomal imbalances provide selective advantage to human embryonic stem cells under enhanced replicative stress conditions

Human embryonic stem cells (hESCs) and embryonal tumors share a number of common features including a compromised G1/S checkpoint. Consequently, these rapidly dividing hESCs and cancer cells undergo elevated levels of replicative stress which is known to induce genomic instability causing chromosomal imbalances. In this context, it is of interest that long-term in vitro cultured hESCs exhibit a remarkable high incidence of segmental DNA copy number gains, some of which are also highly recurrent in certain malignancies such as 17q gain (17q+). The selective advantage of DNA copy number changes in these cells has been attributed to several underlying processes including enhanced proliferation. We hypothesized that these recurrent chromosomal imbalances become rapidly embedded in the cultured hESCs through a replicative stress driven Darwinian selection process. To this end, we compared the effect of hydroxyurea induced replicative stress versus normal growth conditions in an equally-mixed cell population of isogenic euploid and 17q+ hESCs. We could show that 17q+ hESCs rapidly overtook normal hESCs. Our data suggest that recurrent chromosomal segmental gains provide a proliferative advantage to hESCs under increased replicative stress, a process that may also explain the highly recurrent nature of certain imbalances in cancer.

cancer biology↗