Neuronal Lineage Research Articles

Somatostatin interneuron fate-mapping and structure in a Pten knockout model of epilepsy

Disruption of inhibitory interneurons is common in the epileptic brain and is hypothesized to play a pivotal role in epileptogenesis. Abrupt disruption and loss of interneurons is well-characterized in status epilepticus models of epilepsy, however, status epilepticus is a relatively rare cause of epilepsy in humans. How interneuron disruption evolves in other forms of epilepsy is less clear. Here, we explored how somatostatin (SST) interneuron disruption evolves in quadruple transgenic Gli1-CreERT2, Ptenfl/fl, SST-FlpO, and frt-eGFP mice. In these animals, epilepsy develops following deletion of the mammalian target of rapamycin (mTOR) negative regulator phosphatase and tensin homolog (Pten) from a subset of dentate granule cells, while downstream Pten-expressing SST neurons are fate-mapped with green fluorescent protein (GFP). The model captures the genetic complexity of human mTORopathies, in which mutations can be restricted to excitatory neuron lineages, implying that interneuron involvement is later developing and secondary. In dentate granule cell (DGC)-Pten knockouts (KOs), the density of fate-mapped SST neurons was reduced in the hippocampus, but their molecular phenotype was unchanged, with similar percentages of GFP+ cells immunoreactive for SST and parvalbumin (PV). Surviving SST neurons in the dentate gyrus had larger somas, and the density of GFP+ processes in the dentate molecular layer was unchanged despite SST cell loss and expansion of the molecular layer, implying compensatory sprouting of surviving cells. The density of Znt3-immunolabeled puncta, a marker of granule cell presynaptic terminals, apposed to GFP+ processes in the hilus was increased, suggesting enhanced granule cell input to SST neurons. Finally, the percentage of GFP+ cells that were FosB positive was significantly increased, implying that surviving SST neurons are more active. Together, findings suggest that somatostatin-expressing interneurons exhibit a combination of pathological (cell loss) and adaptive (growth) responses to hyperexcitability and seizures driven by upstream Pten KO excitatory granule cells.

Altered PLCβ/IP3/Ca2+ Signaling Pathway Activated by GPRCs in Olfactory Neuronal Precursor Cells Derived from Patients Diagnosed with Schizophrenia.

Background: Schizophrenia (SZ) is a multifactorial chronic psychiatric disorder with a worldwide prevalence of 1%. Altered expression of PLCβ occurs in SZ patients, suggesting alterations in the PLCβ/IP3/Ca2+ signaling pathway. This cascade regulates critical cellular processes in all cell types, including the neuronal lineage; however, there is scarce evidence regarding the functionality of this transduction signaling in neuronal cells derived from SZ patients. Objective: We evaluated the functionality of the PLCβ/IP3/Ca2+ pathway in olfactory neuronal precursor cells (hONPCs) obtained from SZ patients. Methods: Cryopreserved hONPCs isolated from SZ patients and healthy subjects (HS) were thawed. The cellular types in subcultures were corroborated by immunodetection of the multipotency and lineage markers SOX-2, Musashi-1, nestin, and β-III tubulin. The PLCβ/IP3/Ca2+ pathway was activated by GPCR (Gq) ligands (ATP, UTP, serotonin, and epinephrine). In addition, PLCβ and IP3R were directly stimulated by perfusing cells with the activators m-3M3FBS and ADA, respectively. Cytosolic Ca2+ was measured by microfluorometry and by Ca2+ imaging. The amount and subcellular distribution of the PLCβ1 and PLCβ3 isoforms were evaluated by confocal immunofluorescence. IP3 concentration was measured by ELISA. Results: The results show that the increase of cytosolic Ca2+ triggered by GPCR ligands or directly through either PLCβ or IP3R activation was significantly lower in SZ-derived hONPCs, regarding HS-derived cells. Moreover, the relative amount of the PLCβ1 and PLCβ3 isoforms and IP3 production stimulated with m-3M3FBS were reduced in SZ-derived cells. Conclusions: Our results suggest an overall functional impairment in the PLCβ/IP3/Ca2+ signaling pathway in SZ-derived hONPCs.

Independent control of neurogenesis and dorsoventral patterning by NKX2-2.

Human neurogenesis is disproportionately protracted, lasting >10 times longer than in mouse, allowing neural progenitors to undergo more rounds of self-renewing cell divisions and generate larger neuronal populations. In the human spinal cord, expansion of the motor neuron lineage is achieved through a newly evolved progenitor domain called vpMN (ventral motor neuron progenitor) that uniquely extends and expands motor neurogenesis. This behavior of vpMNs is controlled by transcription factor NKX2-2, which in vpMNs is co-expressed with classical motor neuron progenitor (pMN) marker OLIG2. In this study, we sought to determine the molecular basis of NKX2-2-mediated extension and expansion of motor neurogenesis. We found that NKX2-2 represses proneural gene NEUROG2 by two distinct, Notch-independent mechanisms that are respectively apparent in rodent and human spinal progenitors: in rodents (and chick), NKX2-2 represses Olig2 and the motor neuron lineage through its tinman domain, leading to loss of Neurog2 expression. In human vpMNs, however, NKX2-2 represses NEUROG2 but not OLIG2, thereby allowing motor neurogenesis to proceed, albeit in a delayed and protracted manner. Interestingly, we found that ectopic expression of tinman-mutant Nkx2-2 in mouse pMNs phenocopies human vpMNs, repressing Neurog2 but not Olig2, and leading to delayed and protracted motor neurogenesis. Our studies identify a Notch- and tinman-independent mode of Nkx2-2-mediated Neurog2 repression that is observed in human spinal progenitors, but is normally masked in rodents and chicks due to Nkx2-2's tinman-dependent repression of Olig2.

An integrative single-cell atlas for exploring the cellular and temporal specificity of genes related to neurological disorders during human brain development.

Single-cell technologies have enhanced comprehensive knowledge regarding the human brain by facilitating an extensive transcriptomic census across diverse brain regions. Nevertheless, understanding the cellular and temporal specificity of neurological disorders remains ambiguous due to developmental variations. To address this gap, we illustrated the dynamics of disorder risk gene expression under development by integrating multiple single-cell RNA sequencing datasets. We constructed a comprehensive single-cell atlas of the developing human brain, encompassing 393,060 single cells across diverse developmental stages. Temporal analysis revealed the distinct expression patterns of disorder risk genes, including those associated with autism, highlighting their temporal regulation in different neuronal and glial lineages. We identified distinct neuronal lineages that diverged across developmental stages, each exhibiting temporal-specific expression patterns of disorder-related genes. Lineages of nonneuronal cells determined by molecular profiles also showed temporal-specific expression, indicating a link between cellular maturation and the risk of disorder. Furthermore, we explored the regulatory mechanisms involved in early brain development, revealing enriched patterns of fetal cell types associated with neuronal disorders indicative of the prenatal stage's influence on disease determination. Our findings facilitate unbiased comparisons of cell type‒disorder associations and provide insight into dynamic alterations in risk genes during development, paving the way for a deeper understanding of neurological disorders.

Quinic acid contributes to neurogenesis: Targeting Notch pathway a key player in hippocampus

Coordinated proliferation and differentiation of neural stem cells (NSCs) results in continuous neurogenesis. The present study provides novel insights into the Notch intracellular signaling in neuronal cell proliferation, maintenance, migration, and differentiation regulated by naturally based Quinic acid (QA) in primary hippocampal cell culture. Further, this study might help in the discovery and development of lead molecules that can overcome the challenges in the treatment of neurodegenerative diseases. The growth supporting effect of QA was studied using Alamar Blue assay. The migratory potential of QA was evaluated using scratch assay. The in vitro H2O2-induced oxidative stress model was used to upregulate neuronal survival after QA treatment. The RT-qPCR and immunocytochemical analysis were performed for selected markers of Notch signaling to determine the proliferation, differentiation, and maintenance of NSCs at gene and molecular levels. The Mash1 and Ngn2 are the upstream proneural genes of the Notch pathway which were included to evaluate the differentiation of NSCs into mature neurons after treatment with QA.Furthermore, regarding the role of QA in maintaining the pool of NPCs, we used Notch1 and Hes1 markers for proliferation analysis. Also, secondary neuronal markers i.e. Pax6, PCNA, and Mcm2 were included in this study and their gene expression analysis was analyzed following treatment with QA. Based on the study’s results, we suggest that naturally based QA can promote the growth and differentiation of neonatal NSCs residing in hippocampal regions into neuronal lineage. Therefore, we propose that the neurogenic potential of QA can be employed to prevent and treat neurodegenerative diseases.

Neuronal lineage tracing from progenitors in human cortical organoids reveals mechanisms of neuronal production, diversity, and disease

The contribution of progenitor subtypes to generating the billions of neurons produced during human cortical neurogenesis is not well understood. We developed the cortical organoid lineage-tracing (COR-LT) system for human cortical organoids. Differential fluorescent reporter activation in distinct progenitor cells leads to permanent reporter expression, enabling the progenitor cell lineage of neurons to be determined. Surprisingly, nearly all excitatory neurons produced in cortical organoids were generated indirectly from intermediate progenitor cells. Additionally, neurons of different progenitor lineages were transcriptionally distinct. Isogenic lines made from an autistic individual with and without a likely pathogenic CTNNB1 variant demonstrated that the variant substantially altered the proportion of neurons derived from specific progenitor cell lineages, as well as the lineage-specific transcriptional profiles of these neurons, suggesting a pathogenic mechanism for this mutation. These results suggest individual progenitor subtypes play roles in generating the diverse neurons of the human cerebral cortex.

Mitochondria facilitate neuronal differentiation by metabolising nuclear-encoded RNA

Mitochondrial activity directs neuronal differentiation dynamics during brain development. In this context, the long-established metabolic coupling of mitochondria and the eukaryotic host falls short of a satisfactory mechanistic explanation, hinting at an undisclosed facet of mitochondrial function. Here, we reveal an RNA-based inter-organellar communication mode that complements metabolic coupling of host-mitochondria and underpins neuronal differentiation. We show that within minutes of exposure to differentiation cues and activation of the electron transport chain, the mitochondrial outer membrane transiently fuses with the nuclear membrane of neural progenitors, leading to efflux of nuclear-encoded RNAs (neRNA) into the positively charged mitochondrial intermembrane space. Subsequent degradation of mitochondrial neRNAs by Polynucleotide phosphorylase 1 (PNPase) located in the intermembrane space curbs the transcriptomic memory of progenitor cells. Further, acquisition of neRNA by mitochondria leads to a collapse of proton motive force, suppression of ATP production, and a resultant amplification of autophagic flux that attenuates proteomic memory. Collectively, these events force the progenitor cells towards a “tipping point” characterised by emergence of a competing neuronal differentiation program. It appears that neuronal differentiation is a consequence of reprogrammed coupling of metabolomic and transcriptomic landscapes of progenitor cells, with mitochondria emerging as key “reprogrammers” that operate by acquiring and metabolising neRNAs. However, the documented role of mitochondria as “reprogrammers” of differentiation remains to be validated in other neuronal lineages and in vivo.

Left/right asymmetrically expressed ephrin and Flamingo proteins regulate lateralized axon growth in C. elegans.

While the nervous system of bilaterian animals is mainly left-right (L-R) symmetric at the anatomical level, some molecular and functional L-R asymmetries exist. However, the extent of these molecular asymmetries and their functional consequences remain poorly characterized. C. elegans allows to study L-R asymmetries in the nervous system with single-neuron resolution. We have previously shown that a neural bHLH transcription factor, HLH-16/Olig, is L-R asymmetrically expressed in the AIY neuron lineage and regulates AIY axon projections in a L-R asymmetric manner. Here, by combining a candidate approach and single-cell RNA sequencing data analysis, we identify the ephrin protein EFN-2 and the Flamingo protein FMI-1 as downstream targets of HLH-16 that are L-R asymmetrically expressed in the AIY lineage. We show that EFN-2 and FMI-1 collaborate in the L-R asymmetric regulation of axonal growth. EFN-2 may act via a non-canonical receptor of the L1CAM family, SAX-7. Our study reveals novel molecular L-R asymmetries in the C. elegans nervous system and their functional consequences.

CASCADES, a novel SOX2 super-enhancer-associated long noncoding RNA, regulates cancer stem cell specification and differentiation in glioblastoma.

Glioblastoma is the most common primary malignant brain tumor in adults, with a median survival of just over 1 year. The failure of available treatments to achieve remission in patients with glioblastoma (GBM) has been attributed to the presence of cancer stem cells (CSCs), which are thought to play a central role in tumor development and progression and serve as a treatment-resistant cell repository capable of driving tumor recurrence. In fact, the property of "stemness" itself may be responsible for treatment resistance. In this study, we identify a novel long noncoding RNA (lncRNA), cancer stem cell-associated distal enhancer of SOX2 (CASCADES), that functions as an epigenetic regulator in glioma CSCs (GSCs). CASCADES is expressed in isocitrate dehydrogenase (IDH)-wild-type GBM and is significantly enriched in GSCs. Knockdown of CASCADES in GSCs results in differentiation towards a neuronal lineage in a cell- and cancer-specific manner. Bioinformatics analysis reveals that CASCADES functions as a super-enhancer-associated lncRNA epigenetic regulator of SOX2. Our findings identify CASCADES as a critical regulator of stemness in GSCs that represents a novel epigenetic and therapeutic target for disrupting the CSC compartment in glioblastoma.

Joint trajectory inference for single-cell genomics using deep learning with a mixture prior

Trajectory inference methods are essential for analyzing the developmental paths of cells in single-cell sequencing datasets. It provides insights into cellular differentiation, transitions, and lineage hierarchies, helping unravel the dynamic processes underlying development and disease progression. However, many existing tools lack a coherent statistical model and reliable uncertainty quantification, limiting their utility and robustness. In this paper, we introduce VITAE (Variational Inference for Trajectory by AutoEncoder), a statistical approach that integrates a latent hierarchical mixture model with variational autoencoders to infer trajectories. The statistical hierarchical model enhances the interpretability of our framework, while the posterior approximations generated by our variational autoencoder ensure computational efficiency and provide uncertainty quantification of cell projections along trajectories. Specifically, VITAE enables simultaneous trajectory inference and data integration, improving the accuracy of learning a joint trajectory structure in the presence of biological and technical heterogeneity across datasets. We show that VITAE outperforms other state-of-the-art trajectory inference methods on both real and synthetic data under various trajectory topologies. Furthermore, we apply VITAE to jointly analyze three distinct single-cell RNA sequencing datasets of the mouse neocortex, unveiling comprehensive developmental lineages of projection neurons. VITAE effectively reduces batch effects within and across datasets and uncovers finer structures that might be overlooked in individual datasets. Additionally, we showcase VITAE's efficacy in integrative analyses of multiomic datasets with continuous cell population structures.

Integrative analysis of long isoform sequencing and functional data identifies distinct cortical layer neuronal subtypes derived from human iPSCs.

Generation of human induced pluripotent stem cells (iPSCs) through reprogramming was a transformational change in the field of regenerative medicine that led to new possibilities for drug discovery and cell replacement therapy. Several protocols have been established to differentiate hiPSCs into neuronal lineages. However, low differentiation efficiency is one of the major drawbacks of these approaches. Here, we compared the efficiency of two methods of neuronal differentiation from iPSCs cultured in two different culture media, StemFlex Medium (SFM) and Essential 8 Medium (E8M). The results indicated that iPSCs cultured in E8M efficiently generated different types of neurons in a shorter time and without the growth of undifferentiated nonneuronal cells in the culture as compared with those generated from iPSCs in SFM. Furthermore, these neurons were validated as functional units immunocytochemically by confirming the expression of mature neuronal markers (i.e., NeuN, β tubulin, and Synapsin I) and whole cell patch-clamp recordings. Long-read single-cell RNA sequencing confirms the presence of upper and deep layer cortical layer excitatory and inhibitory neuronal subtypes in addition to small populations of GABAergic neurons in day 30 neuronal cultures. Pathway analysis indicated that our protocol triggers the signaling transcriptional networks important for the process of neuronal differentiation in vivo.NEW & NOTEWORTHY Low differentiation efficiency is one of the major drawbacks of the existing protocols to differentiate iPSCs into neuronal lineages. Here, we present time-efficient and robust approach of neuronal differentiation leading to the generation of functional brain units, cortical layer neurons. We found iPSCs cultured in Essential 8 media (E8M) resulted in neuronal differentiation without the signs of growth of spontaneously differentiated cells in culture at any point in 35 days compared with Stemflex media (SFM).

Abstract P361: Characterization of a Constitutive Adiponectin-Cre Rat Reveals Expression in Adipocyte, Endothelial and Neuronal Lineages

Introduction: The Dahl salt-sensitive (DahlSS) rat is a valuable model for studying hypertension and blood pressure regulation. To create new genetic tools for probing gene function specifically within adipose tissues in this model, we engineered a constitutive Adipoq-Cre rat on a DahlSS genomic background using CRISPR-Cas9 genome editing. Methods: A P2A-Cre cassette was inserted in-frame with the endogenous Adiponectin gene (ENSRNOG00065003537) to enable bicistronic expression from the major transcript (Adipoq-201; ENSRNOT00060022350.1). CRISPR targeting was achieved by microinjecting rat zygotes with a ribonucleoprotein (RNP) complex consisting of Cas9 protein and single guide RNA with a target near the stop codon, and a homology-directed repair plasmid template carrying the Cre recombinase cassette. To evaluate the pattern of Cre expression, Adipoq-Cre DahlSS rats were crossed with a Rosa-CAG-LSL-tdTomato LE reporter line (RRRC#: 009389). The progeny were analyzed for tdTomato reporter expression by cryo-fluorescence tomography (CFT) at postnatal day 10 (P10) and 10 weeks of age, using a Xerra TM EMIT imaging platform (50um sections). A Zeiss LSM 880 system was used to image fresh Vectashield-mounted tissues with a Plan-Apochromat 20x objective and a 561nm laser. Results: Strong CFT signal was detected in all examined adipose depots including subcutaneous, gonadal, and retroperitoneal white adipose tissue, interscapular brown adipose tissue, and perivascular adipose tissue (PVAT). Expression was also detected in the CNS. Confocal imaging of mesenteric PVAT and thoracic aorta PVAT revealed expression in adipocytes, endothelial cells, and peripheral nerves. Conclusion: The newly developed constitutive DahlSS Adipoq-Cre recombinase knockin drives expression in white and brown adipose depots but the presence of expression in non-adipocyte cells suggests either developmental or adult adiponectin expression in endothelial and neuronal lineages, limiting its ability to drive strictly adipose-specific gene expression.

Directing Rat Hair Follicle Stem Cells Toward Neuronal Lineage With Enhanced Trophic Factor Expression

Background: Hair follicle stem cells (HFSCs) are promising candidates for cell-based therapies in neurodegenerative diseases because of their ability to differentiate into neural lineages and exert paracrine effects in damaged tissues. However, their clinical application faces challenges, particularly in efficiently guiding them toward neural lineages. This study explores using chick embryo extract (CEE) to enhance HFSCs’ secretory capacity and neuronal differentiation. Materials and Methods: HFSCs from rat whisker pads were cultured in growth medium supplemented with either 20% FBS or a combination of 10% FBS and 10% CEE, transitioning to 20% FBS after the first subculture. We conducted gene expression profiling of lineage commitment markers and neurotrophic factors in both experimental groups, alongside morphological assessments and protein expression analyses. Results: CEE supplementation during migration increased neuronal differentiation, evidenced by more cells with neurites and higher MAP2 expression at both the gene and protein levels. CEE also inhibited the expression of PDGFR-α, indicating a suppression of differentiation toward Schwann cells. Furthermore, we observed increased levels of trophic factors such as BDNF and VEGF at passage 3 induced by CEE supplementation. Conclusions: Enhancing the neuronal lineage commitment of hair follicle stem cells (HFSCs) and boosting the expression of trophic and angiogenic factors through short-term CEE preconditioning during their migratory stage presents a compelling approach. This strategy holds great promise in enhancing the effectiveness of stem cell-based therapies for neurological disorders.

GABAergic neuronal lineage development determines clinically actionable targets in diffuse hemispheric glioma, H3G34-mutant

Diffuse hemispheric gliomas, H3G34R/V-mutant (DHG-H3G34), are lethal brain tumors lacking targeted therapies. They originate from interneuronal precursors; however, leveraging this origin for therapeutic insights remains unexplored. Here, we delineate a cellular hierarchy along the interneuron lineage development continuum, revealing that DHG-H3G34 mirror spatial patterns of progenitor streams surrounding interneuron nests, as seen during human brain development. Integrating these findings with genome-wide CRISPR-Cas9 screens identifies genes upregulated in interneuron lineage progenitors as major dependencies. Among these, CDK6 emerges as a targetable vulnerability: DHG-H3G34 tumor cells show enhanced sensitivity to CDK4/6 inhibitors and a CDK6-specific degrader, promoting a shift toward more mature interneuron-like states, reducing tumor growth, and prolonging xenograft survival. Notably, a patient with progressive DHG-H3G34 treated with a CDK4/6 inhibitor achieved 17months of stable disease. This study underscores interneuronal progenitor-like states, organized in characteristic niches, as a distinct vulnerability in DHG-H3G34, highlighting CDK6 as a promising clinically actionable target.

Accurate long-read transcript discovery and quantification at single-cell, pseudo-bulk and bulk resolution with Isosceles

Accurate detection and quantification of mRNA isoforms from nanopore long-read sequencing remains challenged by technical noise, particularly in single cells. To address this, we introduce Isosceles, a computational toolkit that outperforms other methods in isoform detection sensitivity and quantification accuracy across single-cell, pseudo-bulk and bulk resolution levels, as demonstrated using synthetic and biologically-derived datasets. Here we show Isosceles improves the fidelity of single-cell transcriptome quantification at the isoform-level, and enables flexible downstream analysis. As a case study, we apply Isosceles, uncovering coordinated splicing within and between neuronal differentiation lineages. Isosceles is suitable to be applied in diverse biological systems, facilitating studies of cellular heterogeneity across biomedical research applications.

AUTS2 disruption causes neuronal differentiation defects in human cerebral organoids through hyperactivation of the WNT/β-catenin pathway

Individuals with the Autism Susceptibility Candidate 2 (AUTS2) gene disruptions exhibit symptoms such as intellectual disability, microcephaly, growth retardation, and distinct skeletal and facial differences. The role of AUTS2 in neurodevelopment has been investigated using animal and embryonic stem cell models. However, the precise molecular mechanisms of how AUTS2 influences neurodevelopment, particularly in humans, are not thoroughly understood. Our study employed a 3D human cerebral organoid culture system, in combination with genetic, genomic, cellular, and molecular approaches, to investigate how AUTS2 impacts neurodevelopment through cellular signaling pathways. We used CRISPR/Cas9 technology to create AUTS2-deficient human embryonic stem cells and then generated cerebral organoids with these cells. Our transcriptomic analyses revealed that the absence of AUTS2 in cerebral organoids reduces the populations of cells committed to the neuronal lineage, resulting in an overabundance of cells with a transcription profile resembling that of choroid plexus (ChP) cells. Intriguingly, we found that AUTS2 negatively regulates the WNT/β-catenin signaling pathway, evidenced by its overactivation in AUTS2-deficient cerebral organoids and in luciferase reporter cells lacking AUTS2. Importantly, treating the AUTS2-deficient cerebral organoids with a WNT inhibitor reversed the overexpression of ChP genes and increased the downregulated neuronal gene expression. This study offers new insights into the role of AUTS2 in neurodevelopment and suggests potential targeted therapies for neurodevelopmental disorders.

Rev-erbα regulate neurogenesis through suppression of Sox2 in neuronal cells to regenerate dopaminergic neurons and abates MPP+ induced neuroinflammation

Parkinson's disease is a progressive neurodegenerative disease that affects the motor and non-motor circuits of the brain. Currently, there are no promising therapeutic measures for Parkinson's disease, and most strategies designed to alleviate the Parkinson's disease are palliative. The dearth of therapeutic interventions in Parkinson's disease has driven attention in the search for targets that may augment dopamine secretion, promote differentiation towards dopaminergic neuronal lineage, or aid in neuroprotection from neuronal stress and inflammation, and prevent Parkinson's disease associated motor impairment and behavioural chaos.The study first reports that Rev-erbα plays an important role in regulating the differentiation of undifferentiated neuronal cells towards dopaminergic neurons through abating Sox2 expression in human SH-SY5Y cells. Rev-erbα directly binds to the human Sox2 promoter region and represses their expression to promote differentiation towards dopaminergic neurons. We have reported a novel mechanism of Rev-erbα which effectively abrogates 1-methyl-4-phenylpyridinium induced cytotoxicity, inflammation, and oxidative stress, exerted a beneficial effect on transmembrane potential, and suppressed apoptosis in the neuronal in vitro model of Parkinson's disease.Rev-erbα ligand SR9011 was observed to ease the disease severity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced mouse model of Parkinson's disease. Rev-erbα alleviates the locomotor behavioural impairment, prevents cognitive decline and promotes motor coordination in mice. Administration of Rev-erbα ligand also helps in replenishing the dopaminergic neurons and abrogating the neurotoxin mediated toxicity in an in vitro and in vivo Parkinson's disease model.We conclude that Rev-erbα emerges as a moonlighting nuclear receptor that could be targeted in the treatment and alleviation of Parkinson disease.

NEUROD1: transcriptional and epigenetic regulator of human and mouse neuronal and endocrine cell lineage programs.

Transcription factors belonging to the basic helix-loop-helix (bHLH) family are key regulators of cell fate specification and differentiation during development. Their dysregulation is implicated not only in developmental abnormalities but also in various adult diseases and cancers. Recently, the abilities of bHLH factors have been exploited in reprogramming strategies for cell replacement therapy. One such factor is NEUROD1, which has been associated with the reprogramming of the epigenetic landscape and potentially possessing pioneer factor abilities, initiating neuronal developmental programs, and enforcing pancreatic endocrine differentiation. The review aims to consolidate current knowledge on NEUROD1's multifaceted roles and mechanistic pathways in human and mousecell differentiation and reprogramming, exploring NEUROD1 roles in guiding the development and reprogramming of neuroendocrine cell lineages. The review focuses on NEUROD1's molecular mechanisms, its interactions with other transcription factors, its role as a pioneer factor in chromatin remodeling, and its potential in cell reprogramming. We also show a differential potential of NEUROD1 in differentiation of neurons and pancreatic endocrine cells, highlighting its therapeutic potential and the necessity for further research to fully understand and utilize its capabilities.

Neural Tissue-Like, not Supraphysiological, Electrical Conductivity Stimulates Neuronal Lineage Specification through Calcium Signaling and Epigenetic Modification.

Electrical conductivity is a pivotal biophysical factor for neural interfaces, though optimal values remain controversial due to challenges isolating this cue. To address this issue, conductive substrates made of carbon nanotubes and graphene oxide nanoribbons, exhibiting a spectrum of conductivities from 0.02 to 3.2Sm-1, while controlling other surface properties is designed. The focus is to ascertain whether varying conductivity in isolation has any discernable impact on neural lineage specification. Remarkably, neural-tissue-like low conductivity (0.02-0.1Sm-1) prompted neural stem/progenitor cells to exhibit a greater propensity toward neuronal lineage specification (neurons and oligodendrocytes, not astrocytes) compared to high supraphysiological conductivity (3.2Sm-1). High conductivity instigated the apoptotic process, characterized by increased apoptotic fraction and decreased neurogenic morphological features, primarily due to calcium overload. Conversely, cells exposed to physiological conductivity displayed epigenetic changes, specifically increased chromatin openness with H3acetylation (H3ac) and neurogenic-transcription-factor activation, along with a more balanced intracellular calcium response. The pharmacological inhibition of H3ac further supported the idea that such epigenetic changes might play a key role in driving neuronal specification in response to neural-tissue-like, not supraphysiological, conductive cues. These findings underscore the necessity of optimal conductivity when designing neural interfaces and scaffolds to stimulate neuronal differentiation and facilitate the repair process.

Substrate stress relaxation regulates neural stem cell fate commitment

Adult neural stem cells (NSCs) reside in the dentate gyrus of the hippocampus, and their capacity to generate neurons and glia plays a role in learning and memory. In addition, neurodegenerative diseases are known to be caused by a loss of neurons and glial cells, resulting in a need to better understand stem cell fate commitment processes. We previously showed that NSC fate commitment toward a neuronal or glial lineage is strongly influenced by extracellular matrix stiffness, a property of elastic materials. However, tissues in vivo are not purely elastic and have varying degrees of viscous character. Relatively little is known about how the viscoelastic properties of the substrate impact NSC fate commitment. Here, we introduce a polyacrylamide-based cell culture platform that incorporates mismatched DNA oligonucleotide-based cross-links as well as covalent cross-links. This platform allows for tunable viscous stress relaxation properties via variation in the number of mismatched base pairs. We find that NSCs exhibit increased astrocytic differentiation as the degree of stress relaxation is increased. Furthermore, culturing NSCs on increasingly stress-relaxing substrates impacts cytoskeletal dynamics by decreasing intracellular actin flow rates and stimulating cyclic activation of the mechanosensitive protein RhoA. Additionally, inhibition of motor-clutch model components such as myosin II and focal adhesion kinase partially or completely reverts cells to lineage distributions observed on elastic substrates. Collectively, our results introduce a unique system for controlling matrix stress relaxation properties and offer insight into how NSCs integrate viscoelastic cues to direct fate commitment.