Proteomic analysis of human iPSC-derived sensory neurons implicates cell stress and microtubule dynamics dysfunction in bortezomib-induced peripheral neurotoxicity

Human sensory-like neuron surfaceome analysis

Acral and triggerable pain is a hallmark of diseases involving small nerve fiber impairment, yet the underlying cellular mechanisms remain elusive. A key role is attributed to pain-related proteins located within the neuronal plasma membrane of nociceptive neurons. To explore this, we employed human induced pluripotent stem cell-derived sensory-like neurons and enriched their surface proteins by biotinylation. Samples from three independent cell differentiations were analyzed via liquid chromatography tandem mass spectrometry. Detected proteins were categorized by cellular location and function, followed by generating an interaction network for deregulated surface proteins. Gene expression of selected proteins was quantified using real-time PCR. A comparative analysis was performed between a patient with Fabry disease (FD) and a healthy control, which we used as model system. We successfully extracted surfaceome proteins from human sensory-like neurons, revealing deregulation of 48 surface proteins in FD-derived neurons. Among the candidates with potential involvement in pain pathophysiology were CACNA2D3, GPM6A, EGFR, and ABCA7. Despite the lack of gene expression differences in these candidates, the interaction network indicated compromised neuronal network integrity. Our approach successfully enabled the extraction and comprehensive analysis of the surfaceome from human sensory-like neurons, establishing a novel methodological framework for investigating human sensory-like neuron biology and cellular disease mechanisms.

Selection of DNA Aptamers That Promote Neurite Outgrowth in Human iPSC-Derived Sensory Neuron Organoid Cultures

Sensory neurons in the dorsal root ganglia transmit sensory signals from the periphery to the central nervous system. Induced pluripotent stem cell derived models of sensory neurons and dorsal root ganglia are among the most advanced available tools for the study of sensory neuron activity and development in human genetic backgrounds. However, few available reagents modify sensory neuron growth with disease or other model-relevant outcomes. Small molecules, peptides, or oligonucleotides that predictably alter sensory neuron behavior in these contexts would be valuable tools with potentially wide-ranging application. Here we describe the selection and characterization of DNA aptamers that specifically interact with human sensory neurons. Several selected aptamers increase neurite outgrowth from sensory neuron organoid cultures after single-dose treatments.

DNA aptamers that modulate biological activity of model neurons

There is an urgent need for agents that promote health and regeneration of cells and tissues, specifically to treat diseases of the aging nervous system. Age-associated nervous system degeneration and various diseases are driven by many different biochemical stresses, often making it difficult to target any one disease cause. Our laboratory has previously identified DNA aptamers with apparent regenerative properties in murine models of multiple sclerosis by selecting aptamers that bind oligodendrocyte membrane preparations. Here, we selected from vast libraries of molecules (∼1014 unique DNAs) those with the ability to bind cultured human SH-SY5Y neuroblastoma cells as a neuronal model, followed by screening for aptamers capable of eliciting biological responses, with validation of binding in differentiated SH-SY5Y, human induced pluripotent stem cell (iPSC)-derived sensory neurons, and human embryonic stem cell (hESC)-derived cortical neurons. This demonstrates a proof-of-concept workflow to identify biologically active aptamers by cycles of cell selection.

Chemotherapy-induced peripheral neuropathy models constructed from human induced pluripotent stem cells and directly converted cells: a systematic review

ABSTRACT

Developments in human cellular reprogramming now allow for the generation of human neurons for in vitro disease modelling. This technique has since been used for chemotherapy-induced peripheral neuropathy (CIPN) research, resulting in the description of numerous CIPN models constructed from human neurons. This systematic review provides a critical analysis of available models and their methodological considerations (ie, used cell type and source, CIPN induction strategy, and validation method) for prospective researchers aiming to incorporate human in vitro models of CIPN in their research. The search strategy was developed with assistance from a clinical librarian and conducted in MEDLINE (PubMed) and Embase (Ovid) on September 26, 2023. Twenty-six peer-reviewed experimental studies presenting original data about human reprogrammed nonmotor neuron cell culture systems and relevant market available chemotherapeutics drugs were included. Virtually, all recent reports modeled CIPN using nociceptive dorsal root ganglion neurons. Drugs known to cause the highest incidence of CIPN were most used. Furthermore, treatment effects were almost exclusively validated by the acute effects of chemotherapeutics on neurite dynamics and cytotoxicity parameters, enabling the extrapolation of the half-maximal inhibitory concentration for the 4 most used chemotherapeutics. Overall, substantial heterogeneity was observed in the way studies applied chemotherapy and reported their findings. We therefore propose 6 suggestions to improve the clinical relevance and appropriateness of human cellular reprogramming-derived CIPN models.

Abnormal neural differentiation in response to graphene quantum dots through histone modification interference

Graphene quantum dots (GQDs) have been broadly applied in biomedicine in recent years, and their environmental exposure and toxicological impacts have raised increasing concerns. The nanosafety assessment on the nervous system is one of the most important aspects, and potential effects of GQDs on neurodevelopment and the underlying mechanism are still elusive. In this study, the neural developmental toxicities of OH-GQDs and NH₂-GQDs were investigated using the mouse embryonic stem cells (mESCs). The results revealed that OH-GQDs significantly inhibited the ectoderm development, and reduced the neural precursor formation and neurogenesis during the neural differentiation of the mESCs. The exploration on the mechanism uncovered that the increased enrichment of H3K27me3 at the promoter region of the Smad6 gene was involved in histone modification-activated BMP signal pathway, which consequently influenced its regulatory effects on neural differentiation. Additionally, OH-GQDs elicited a stronger effect on inducing the imbalance of histone modification, and resulted in higher latency of neural differentiation disturbance than did NH₂-GQDs, suggesting surface functionalization-specific effects of GQDs on neurodevelopmental toxicity. This study would provide new insights in not only the adverse effects of GQDs on neurodevelopment, but also the influence from the chemical modification of GQDs on their bioactivities.

Bortezomib-induced neurotoxicity in human neurons is the consequence of nicotinamide adenine dinucleotide depletion

The proteosome inhibitor bortezomib has revolutionized the treatment of multiple hematologic malignancies, but in many cases, its efficacy is limited by a dose-dependent peripheral neuropathy. We show that human induced pluripotent stem cell (hiPSC)-derived motor neurons and sensory neurons provide a model system for the study of bortezomib-induced peripheral neuropathy, with promising implications for furthering the mechanistic understanding of and developing treatments for preventing axonal damage. Human neurons in tissue culture displayed distal-to-proximal neurite degeneration when exposed to bortezomib. This process coincided with disruptions in mitochondrial function and energy homeostasis, similar to those described in rodent models of bortezomib-induced neuropathy. Moreover, although the degenerative process was unaffected by inhibition of caspases, it was completely blocked by exogenous nicotinamide adenine dinucleotide (NAD+), a mediator of the SARM1-dependent axon degeneration pathway. We demonstrate that bortezomib-induced neurotoxicity in relevant human neurons proceeds through mitochondrial dysfunction and NAD+ depletion-mediated axon degeneration, raising the possibility that targeting these changes might provide effective therapeutics for the prevention of bortezomib-induced neuropathy and that modeling chemotherapy-induced neuropathy in human neurons has utility.

Ubiquitin Proteasome System and Microtubules Are Master Regulators of Central and Peripheral Nervous System Axon Degeneration

Axonal degeneration is an active process that differs from neuronal death, and it is the hallmark of many disorders affecting the central and peripheral nervous system. Starting from the analyses of Wallerian degeneration, the simplest experimental model, here we describe how the long projecting neuronal populations affected in Parkinson’s disease and chemotherapy-induced peripheral neuropathies share commonalities in the mechanisms and molecular players driving the earliest phase of axon degeneration. Indeed, both dopaminergic and sensory neurons are particularly susceptible to alterations of microtubules and axonal transport as well as to dysfunctions of the ubiquitin proteasome system and protein quality control. Finally, we report an updated review on current knowledge of key molecules able to modulate these targets, blocking the on-going axonal degeneration and inducing neuronal regeneration. These molecules might represent good candidates for disease-modifying treatment, which might expand the window of intervention improving patients’ quality of life.

Alternative Splicing Mechanisms Underlying Opioid-Induced Hyperalgesia

Prolonged use of opioids can cause opioid-induced hyperalgesia (OIH). The impact of alternative splicing on OIH remains partially characterized. A study of the absolute and relative modes of action of alternative splicing further the understanding of the molecular mechanisms underlying OIH. Differential absolute and relative isoform profiles were detected in the trigeminal ganglia and nucleus accumbens of mice presenting OIH behaviors elicited by chronic morphine administration relative to control mice. Genes that participate in glutamatergic synapse (e.g., Grip1, Grin1, Wnk3), myelin protein processes (e.g., Mbp, Mpz), and axon guidance presented absolute and relative splicing associated with OIH. Splicing of genes in the gonadotropin-releasing hormone receptor pathway was detected in the nucleus accumbens while splicing in the vascular endothelial growth factor, endogenous cannabinoid signaling, circadian clock system, and metabotropic glutamate receptor pathways was detected in the trigeminal ganglia. A notable finding was the prevalence of alternatively spliced transcription factors and regulators (e.g., Ciart, Ablim2, Pbx1, Arntl2) in the trigeminal ganglia. Insights into the nociceptive and antinociceptive modulatory action of Hnrnpk were gained. The results from our study highlight the impact of alternative splicing and transcriptional regulators on OIH and expose the need for isoform-level research to advance the understanding of morphine-associated hyperalgesia.