Post-Developmental Roles of Notch Signaling in the Nervous System

Overexpression of EGFL7 promotes angiogenesis and nerve regeneration in peripheral nerve injury

Peripheral nerve injury (PNI) often leads to significant functional impairment. Here, we investigated the impact of epidermal growth factor-like domain-containing protein 7 (EGFL7) on angiogenesis and nerve regeneration following PNI. Using a sciatic nerve injury model, we assessed nerve function using the sciatic nerve function index. We analyzed the expression levels of EGFL7, forkhead box proteins A1 (FOXA1), nerve growth factor (NGF), brain-derived neurotrophic factors (BDNF), Neurofilament 200 (NF200), myelin protein zero (P0), cell adhesion molecule 1 (CD31), vascular endothelial growth factor (VEGF), and NOTCH-related proteins in tissues and cells. Cell proliferation, migration, and angiogenesis were evaluated through cell counting kit assays, 5-ethynyl-2'deoxyuridine staining, and Transwell assays. We investigated the binding of FOXA1 to the EGFL7 promoter using dual-luciferase assays and chromatin immunoprecipitation. We observed decreased EGFL7 expression and increased FOXA1 expression in PNI, and EGFL7 overexpression alleviated gastrocnemius muscle atrophy, increased muscle weight, and improved motor function. Additionally, EGFL7 overexpression enhanced Schwann cell and endothelial cell proliferation and migration, promoted tube formation, and upregulated NGF, BDNF, NF200, P0, CD31, and VEGF expression. FOXA1 was found to bind to the EGFL7 promoter region, inhibiting EGFL7 expression and activating the NOTCH signaling pathway. Notably, FOXA1 overexpression counteracted the effects of EGFL7 on Schwann cells and endothelial cells. In conclusion, EGFL7 holds promise as a therapeutic molecule for treating sciatic nerve injury.

Cephalic ganglia transcriptomics of the American cockroach Periplaneta americana (Blattodea: Blattidae)

The American cockroach Periplaneta americana (L.) (Blattodea, Blattidae) has been a model organism for biochemical and physiological study for almost a century, however, its use does not benefit from the genetic tools found in key model species such as Drosophila melanogaster. To facilitate the use of the cockroach as a model system in neuroscience and to serve as a foundation for functional and translational experimentation, a transcriptome of the cephalic ganglia was assembled and annotated, and differential expression profiles between these ganglia were assessed. The transcriptome assembly yielded >400 k transcripts, with >40 k putative coding sequences. Gene ontology and protein domain searches indicate the cerebral and gnathal ganglia (GNG) have distinct genetic expression profiles. The developmental Toll signaling pathway appears to be active in the adult central nervous system (CNS), which may suggest a separate role for this pathway besides innate immune activation or embryonic development. The catabolic glycolytic and citric acid cycle enzymes are well represented in both ganglia, but key enzymes are more highly expressed in the GNG. Both ganglia express gluconeogenic and trehaloneogenic enzymes, suggesting a larger role of the CNS in regulating hemolymph sugar homeostasis than previously appreciated. The annotation and quantification of the cephalic ganglia transcriptome reveal both canonical and novel pathways in signaling and metabolism in an adult insect and lay a foundation for future functional and genetic analysis.

Transcriptomic profiling of sciatic nerves and dorsal root ganglia reveals site-specific effects of prediabetic neuropathy

Peripheral neuropathy (PN) is a severe and frequent complication of obesity, prediabetes, and type 2 diabetes characterized by progressive distal-to-proximal peripheral nerve degeneration. However, a comprehensive understanding of the mechanisms underlying PN, and whether these mechanisms change during PN progression, is currently lacking. Here, gene expression data were obtained from distal (sciatic nerve; SCN) and proximal (dorsal root ganglia; DRG) injury sites of a high-fat diet (HFD)-induced mouse model of obesity/prediabetes at early and late disease stages. Self-organizing map and differentially expressed gene analyses followed by pathway enrichment analysis identified genes and pathways altered across disease stage and injury site. Pathways related to immune response, inflammation, and glucose and lipid metabolism were consistently dysregulated with HFD-induced PN, irrespective of injury site. However, regulation of oxidative stress was unique to the SCN while dysregulated Hippo and Notch signaling were only observed in the DRG. The role of the immune system and inflammation in disease progression was supported by an increase in the percentage of immune cells in the SCN with PN progression. Finally, when comparing these data to transcriptomic signatures from human patients with PN, we observed conserved pathways related to metabolic dysregulation across species, highlighting the translational relevance of our mouse data. Our findings demonstrate that PN is associated with distinct site-specific molecular re-programming in the peripheral nervous system, identifying novel, clinically relevant therapeutic targets.

Notch Signaling: An Emerging Paradigm in the Pathogenesis of Reproductive Disorders and Diverse Pathological Conditions

The highly conserved Notch pathway, a pillar of juxtacrine signaling, orchestrates intricate intercellular communication, governing diverse developmental and homeostatic processes through a tightly regulated cascade of proteolytic cleavages. This pathway, culminating in the migration of the Notch intracellular domain (NICD) to the nucleus and the subsequent activation of downstream target genes, exerts a profound influence on a plethora of molecular processes, including cell cycle progression, lineage specification, cell-cell adhesion, and fate determination. Accumulating evidence underscores the pivotal role of Notch dysregulation, encompassing both gain and loss-of-function mutations, in the pathogenesis of numerous human diseases. This review delves deep into the multifaceted roles of Notch signaling in cellular dynamics, encompassing proliferation, differentiation, polarity maintenance, epithelial-mesenchymal transition (EMT), tissue regeneration/remodeling, and its intricate interplay with other signaling pathways. We then focus on the emerging landscape of Notch aberrations in gynecological pathologies predisposing individuals to infertility. By highlighting the exquisite conservation of Notch signaling in Drosophila and its power as a model organism, we pave the way for further dissection of disease mechanisms and potential therapeutic interventions through targeted modulation of this master regulatory pathway.

Novel Genome-Engineered H Alleles Differentially Affect Lateral Inhibition and Cell Dichotomy Processes during Bristle Organ Development

Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in Drosophila. By binding to the Notch signal transducer Suppressor of Hairless (Su(H)), H assembles repressor complexes onto Notch target genes. Using genome engineering, three new H alleles, HFA, HLLAA and HWA were generated and a phenotypic series was established by several parameters, reflecting the residual H-Su(H) binding capacity. Occasionally, homozygous HWA flies develop to adulthood. They were compared with the likewise semi-viable HNN allele affecting H-Su(H) nuclear entry. The H homozygotes were short-lived, sterile and flightless, yet showed largely normal expression of several mitochondrial genes. Typical for H mutants, both HWA and HNN homozygous alleles displayed strong defects in wing venation and mechano-sensory bristle development. Strikingly, however, HWA displayed only a loss of bristles, whereas bristle organs of HNN flies showed a complete shaft-to-socket transformation. Apparently, the impact of HWA is restricted to lateral inhibition, whereas that of HNN also affects the respective cell type specification. Notably, reduction in Su(H) gene dosage only suppressed the HNN bristle phenotype, but amplified that of HWA. We interpret these differences as to the role of H regarding Su(H) stability and availability.

SNP and Structural Study of the Notch Superfamily Provides Insights and Novel Pharmacological Targets against the CADASIL Syndrome and Neurodegenerative Diseases

The evolutionary conserved Notch signaling pathway functions as a mediator of direct cell-cell communication between neighboring cells during development. Notch plays a crucial role in various fundamental biological processes in a wide range of tissues. Accordingly, the aberrant signaling of this pathway underlies multiple genetic pathologies such as developmental syndromes, congenital disorders, neurodegenerative diseases, and cancer. Over the last two decades, significant data have shown that the Notch signaling pathway displays a significant function in the mature brains of vertebrates and invertebrates beyond neuronal development and specification during embryonic development. Neuronal connection, synaptic plasticity, learning, and memory appear to be regulated by this pathway. Specific mutations in human Notch family proteins have been linked to several neurodegenerative diseases including Alzheimer's disease, CADASIL, and ischemic injury. Neurodegenerative diseases are incurable disorders of the central nervous system that cause the progressive degeneration and/or death of brain nerve cells, affecting both mental function and movement (ataxia). There is currently a lot of study being conducted to better understand the molecular mechanisms by which Notch plays an essential role in the mature brain. In this study, an in silico analysis of polymorphisms and mutations in human Notch family members that lead to neurodegenerative diseases was performed in order to investigate the correlations among Notch family proteins and neurodegenerative diseases. Particular emphasis was placed on the study of mutations in the Notch3 protein and the structure analysis of the mutant Notch3 protein that leads to the manifestation of the CADASIL syndrome in order to spot possible conserved mutations and interpret the effect of these mutations in the Notch3 protein structure. Conserved mutations of cysteine residues may be candidate pharmacological targets for the potential therapy of CADASIL syndrome.

Dissecting Schizophrenia Biology Using Pleiotropy with Cognitive Genomics

Given the increasingly large number of loci discovered by psychiatric GWAS, specification of the key biological pathways underlying these loci has become a priority for the field. We have previously leveraged the pleiotropic genetic relationships between schizophrenia and two cognitive phenotypes (educational attainment and cognitive task performance) to differentiate two subsets of illness-relevant SNPs: (1) those with "concordant" alleles, which are associated with reduced cognitive ability/education and increased schizophrenia risk; and (2) those with "discordant" alleles linked to reduced educational and/or cognitive levels but lower schizophrenia susceptibility. In the present study, we extend our prior work, utilizing larger input GWAS datasets and a more powerful statistical approach to pleiotropic meta-analysis, the Pleiotropic Locus Exploration and Interpretation using Optimal test (PLEIO). Our pleiotropic meta-analysis of schizophrenia and the two cognitive phenotypes revealed 768 significant loci (159 novel). Among these, 347 loci harbored concordant SNPs, 270 encompassed discordant SNPs, and 151 "dual" loci contained concordant and discordant SNPs. Competitive gene-set analysis using MAGMA related concordant SNP loci with neurodevelopmental pathways (e.g., neurogenesis), whereas discordant loci were associated with mature neuronal synaptic functions. These distinctions were also observed in BrainSpan analysis of temporal enrichment patterns across developmental periods, with concordant loci containing more prenatally expressed genes than discordant loci. Dual loci were enriched for genes related to mRNA translation initiation, representing a novel finding in the schizophrenia literature.

Genetics of congenital heart disease

During embryonic development, the cardiovascular system and the central nervous system exhibit a coordinated developmental process through intricate interactions. Congenital heart disease (CHD) refers to structural or functional abnormalities that occur during embryonic or prenatal heart development and is the most common congenital disorder. One of the most common complications in CHD patients is neurodevelopmental disorders (NDD). However, the specific mechanisms, connections, and precise ways in which CHD co-occurs with NDD remain unclear. According to relevant research, both genetic and non-genetic factors are significant contributors to the co-occurrence of sporadic CHD and NDD. Genetic variations, such as chromosomal abnormalities and gene mutations, play a role in the susceptibility to both CHD and NDD. Further research should aim to identify common molecular mechanisms that underlie the co-occurrence of CHD and NDD, possibly originating from shared genetic mutations or shared gene regulation. Therefore, this review article summarizes the current advances in the genetics of CHD co-occurring with NDD, elucidating the application of relevant gene detection techniques. This is done with the aim of exploring the genetic regulatory mechanisms of CHD co-occurring with NDD at the gene level and promoting research and treatment of developmental disorders related to the cardiovascular and central nervous systems.

Two Sides of The Same Coin: Normal and Tumoral Stem Cells, The Relevance of In Vitro Models and Therapeutic Approaches: The Experience with Zika Virus in Nervous System Development and Glioblastoma Treatment

Neural stem cells (NSCs) were described for the first time more than two decades ago for their ability to differentiate into all neural cell lineages. The isolation of NSCs from adults and embryos was carried out by various laboratories and in different species, from mice to humans. Similarly, no more than two decades ago, cancer stem cells were described. Cancer stem cells, previously identified in hematological malignancies, have now been isolated from several solid tumors (breast, brain, and gastrointestinal compartment). Though the origin of these cells is still unknown, there is a wide consensus about their role in tumor onset, propagation and, in particular, resistance to treatments. Normal and neoplastic neural stem cells share common characteristics, and can thus be considered as two sides of the same coin. This is particularly true in the case of the Zika virus (ZIKV), which has been described as an inhibitor of neural development by specifically targeting NSCs. This understanding prompted us and other groups to evaluate ZIKV action in glioblastoma stem cells (GSCs). The results indicate an oncolytic activity of this virus vs. GSCs, opening potentially new possibilities in glioblastoma treatment.

Notch signaling is activated in knee-innervating dorsal root ganglia in experimental models of osteoarthritis joint pain

BACKGROUND

We aimed to explore activation of the Notch signaling pathway in knee-innervating lumbar dorsal root ganglia (DRG) in the course of experimental osteoarthritis (OA) in mice, and its role in knee hyperalgesia.

METHODS

Cultured DRG cells were stimulated with the TLR4 agonist, lipopolysaccharide (LPS). Notch signaling in the cells was either inhibited with the γ-secretase inhibitor, DAPT, or with soluble Jagged1, or activated through immobilized Jagged1. CCL2 production was analyzed at mRNA and protein levels. In in vivo experiments, knee hyperalgesia was induced in naïve mice through intra-articular (IA) injection of LPS. The effect of inhibiting Notch signaling was examined by pre-injecting DAPT one hour before LPS. OA was induced through surgical destabilization of the medial meniscus (DMM) in male C57BL/6 mice. Gene expression in DRG was analyzed by qRT-PCR and RNAscope in situ hybridization. Activated Notch protein (NICD) expression in DRG was evaluated by ELISA and immunofluorescence staining. DAPT was injected IA 12 weeks post DMM to inhibit Notch signaling, followed by assessing knee hyperalgesia and CCL2 expression in the DRG.

RESULTS

In DRG cell cultures, LPS increased NICD in neuronal cells. Inhibition of Notch signaling with either DAPT or soluble Jagged1 attenuated LPS-induced increases of Ccl2 mRNA and CCL2 protein. Conversely, activating Notch signaling with immobilized Jagged1 enhanced these LPS effects. In vivo, IA injection of LPS increased expression of Notch genes and NICD in the DRG. Pre-injection of DAPT prior to LPS alleviated LPS-induced knee hyperalgesia, and decreased LPS-induced CCL2 expression in the DRG. Notch signaling genes were differentially expressed in the DRG from late-stage experimental OA. Notch1, Hes1, and NICD were increased in the neuronal cell bodies in DRG after DMM surgery. IA administration of DAPT alleviated knee hyperalgesia post DMM, and decreased CCL2 expression in the DRG.

CONCLUSIONS

These findings suggest a synergistic effect of Notch signaling with TLR4 in promoting CCL2 production and mediating knee hyperalgesia. Notch signaling is activated in knee-innervating lumbar DRG in mice with experimental OA, and is involved in mediating knee hyperalgesia. The pathway may therefore be explored as a target for alleviating OA pain.

Kif21B mediates the effect of estradiol on the morphological plasticity of mouse hippocampal neurons

Introduction

Neurons are polarized cells, and their ability to change their morphology has a functional implication in the development and plasticity of the nervous system in order to establish new connections. Extracellular factors strongly influence neuronal shape and connectivity. For instance, the developmental actions of estradiol on hippocampal neurons are well characterized, and we have demonstrated in previous studies that Ngn3 mediates these actions. On the other hand, Kif21B regulates microtubule dynamics and carries out retrograde transport of the TrkB/brain-derived neurotrophic factor (BDNF) complex, essential for neuronal development.

Methods

In the present study, we assessed the involvement of kinesin Kif21B in the estradiol-dependent signaling mechanisms to regulate neuritogenesis through cultured mouse hippocampal neurons.

Results

We show that estradiol treatment increases BDNF expression, and estradiol and BDNF modify neuron morphology through TrkB signaling. Treatment with K252a, a TrkB inhibitor, decreases dendrite branching without affecting axonal length, whereas. Combined with estradiol or BDNF, it blocks their effects on axons but not dendrites. Notably, the downregulation of Kif21B abolishes the actions of estradiol and BDNF in both the axon and dendrites. In addition, Kif21B silencing also decreases Ngn3 expression, and downregulation of Ngn3 blocks the effect of BDNF on neuron morphology.

Discussion

These results suggest that Kif21B is required for the effects of estradiol and BDNF on neuronal morphology, but phosphorylation-mediated activation of TrkB is essential only for axonal growth. Our results show that the Estradiol/BDNF/TrkB/Kif21B/Ngn3 is a new and essential pathway mediating hippocampal neuron development.

Regulatory role of melatonin in Notch1 signaling pathway in cerebral cortex of Aβ1-42-induced Alzheimer's disease rat model

BACKGROUND

Soluble Amyloid-beta (Aβ) oligomers are thought to play a key role in the pathogenesis of Alzheimer's disease (AD), which is the most common age-associated neurodegenerative diseases with obvious neuropathological changes and functional decline in both cortical and subcortical regions. Melatonin is ubiquitously distributed and multifunctioning indoleamine. Accumulating studies support that melatonin is potential therapeutic molecule for AD through modulating a broad variety of signaling pathways. In recent years, Notch1 signaling pathway is been known involved in dynamic changes in the cellular architecture and function of adult brain, as well as associated with the pathophysiology of AD and other neurodegenerative disorders.

METHODS AND RESULTS

In this study, we performed real-time polymerase chain reaction, immunohistochemistry and western blotting analyses using the cerebral cortical tissues of Aβ_1-42 oligomers-induced AD rats with or without melatonin treatment. Our results showed that soluble Aβ_1-42 oligomers decreased the expression of the main components of Notch1 signaling pathway, Notch1, NICD and Hes1 in the cerebral cortex, and melatonin could restore the level of Notch1, NICD and Hes1.

CONCLUSION

This observation suggests that targeting of Notch1 signaling might be a promising therapeutic approach for AD and other age-associated neurodegenerative diseases, and melatonin might serve as a potential therapeutic agent for AD and other age-associated neurodegenerative diseases.

Stable Expression of dmiR-283 in the Brain Promises Positive Effects in Endurance Exercise on Sleep-Wake Behavior in Aging Drosophila

Sleep-wake stability is imbalanced with natural aging, and microRNAs (miRNAs) play important roles in cell proliferation, apoptosis, and aging; however, the biological functions of miRNAs in regulating aging-related sleep-wake behavior remain unexplored. This study varied the expression pattern of dmiR-283 in Drosophila and the result showed that the aging decline in sleep-wake behavior was caused by the accumulation of brain dmiR-283 expression, whereas the core clock genes cwo and Notch signaling pathway might be suppressed, which regulate the aging process. In addition, to identify exercise intervention programs of Drosophila that promote healthy aging, mir-283^SP/+ and Pdf > mir-283^SP flies were driven to perform endurance exercise for a duration of 3 weeks starting at 10 and 30 days, respectively. The results showed that exercise starting in youth leads to an enhanced amplitude of sleep-wake rhythms, stable periods, increased activity frequency upon awakening, and the suppression of aging brain dmiR-283 expression in mir-283^SP/+ middle-aged flies. Conversely, exercise performed when the brain dmiR-283 reached a certain accumulation level showed ineffective or negative effects. In conclusion, the accumulation of dmiR-283 expression in the brain induced an age-dependent decline in sleep-wake behavior. Endurance exercise commencing in youth counteracts the increase in dmiR-283 in the aging brain, which ameliorates the deterioration of sleep-wake behavior during aging.

Fosthiazate exposure induces oxidative stress, nerve damage, and reproductive disorders in nontarget nematodes

As a forceful nematicide, fosthiazate has been largely applied in the management of root-knot nematodes and other herbivorous nematodes. However, the toxicity of fosthiazate to nontarget nematodes is unclear. To explore the toxicity and the mechanisms of fosthiazate in nontarget nematodes, Caenorhabditis elegans was exposed to 0.01-10 mg/L fosthiazate. The results implied that treatment with fosthiazate at doses above 0.01 mg/L could cause injury to the growth, locomotion behavior, and reproduction of the nematodes. Moreover, L1 larvae were more vulnerable to fosthiazate exposure than L4 larvae. Reactive oxygen species (ROS) production and lipofuscin accumulation were fairly increased in 1 mg/L fosthiazate-exposed nematodes. Treatment with 0.1 mg/L fosthiazate significantly inhibited the activity of acetylcholinesterase (p < 0.01). Furthermore, subacute exposure to 10 mg/L fosthiazate strongly influenced the expression of genes related to oxidative stress, reproduction, and nerve function (e.g., gst-1, sod-1, puf-8, wee-1.3, and ace-1 genes). These findings suggested that oxidative stress, reproduction and nerve disorders could serve as key endpoints of toxicity induced by fosthiazate. The cyp-35a family gene was the main metabolic fosthiazate in C. elegans, and the cyp-35a5 subtype was the most sensitive, with a change in expression level of 2.11-fold compared with the control. These results indicate that oxidative stress and neurological and reproductive disorders played fundamental roles in the toxicity of fosthiazate in C. elegans and may affect the abundance and function of soil nematodes.

An X-linked PLXNB3 mutation identified in patients with congenital heart disease with neurodevelopmental disabilities

BACKGROUND

Congenital heart disease (CHD) is the most common birth defect and is often accompanied by neurodevelopmental disabilities (NDD) which increase the associated mortality. Plexin families are known to play a key role in the development of heart and the occurrence of neurodevelopmental anomalies. However, there has been no report of PLXNB3 mutation in isolated CHD or CHD with concomitant NDD.

METHODS

We performed whole-exome sequencing (WES) on a proband with CHD with neurodevelopmental anomalies and his family members. Targeted sequencing, conservation analysis, AlphaFold, and PyRosetta were performed to identify more pathogenic mutations of PLXNB3. Scratch wound assay, Ki-67 assessment by flow cytometry, and gene expression analysis of heart development related pathway by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were conducted after 24 h transfection in AC16 and HEK293T to investigate the effect of the target mutation.

RESULTS

We identified a pathogenic mutation in the X-linked PLXNB3 gene (c.A4319T p.E1440V). In addition, we found 4 other pathogenic mutations in a cohort of 75 patients with sporadic CHD with NDD. AlphaFold and PyRosetta predicted that these 4 mutations could cause dramatic changes of the PLXNB3 protein structure (root-mean-square deviation score >10 Å). Further functional analysis revealed that this p.E1440V variant inhibits cell migration and proliferation, and affects the activity of key factors in the Notch signaling pathway, myocardial contraction pathway, and neurodevelopmental pathways.

CONCLUSIONS

These findings suggest that PLXNB3 and the p.E1440V variant may be related to the pathogenesis of CHD associated with NDD.

TM2D genes regulate Notch signaling and neuronal function in Drosophila

TM2 domain containing (TM2D) proteins are conserved in metazoans and encoded by three separate genes in each model organism species that has been sequenced. Rare variants in TM2D3 are associated with Alzheimer's disease (AD) and its fly ortholog almondex is required for embryonic Notch signaling. However, the functions of this gene family remain elusive. We knocked-out all three TM2D genes (almondex, CG11103/amaretto, CG10795/biscotti) in Drosophila and found that they share the same maternal-effect neurogenic defect. Triple null animals are not phenotypically worse than single nulls, suggesting these genes function together. Overexpression of the most conserved region of the TM2D proteins acts as a potent inhibitor of Notch signaling at the γ-secretase cleavage step. Lastly, Almondex is detected in the brain and its loss causes shortened lifespan accompanied by progressive motor and electrophysiological defects. The functional links between all three TM2D genes are likely to be evolutionarily conserved, suggesting that this entire gene family may be involved in AD.

Drosophila melanogaster: A Powerful Tiny Animal Model for the Study of Metabolic Hepatic Diseases

Animal experimentation is limited by unethical procedures, time-consuming protocols, and high cost. Thus, the development of innovative approaches for disease treatment based on alternative models in a fast, safe, and economic manner is an important, yet challenging goal. In this paradigm, the fruit-fly Drosophila melanogaster has become a powerful model for biomedical research, considering its short life cycle and low-cost maintenance. In addition, biological processes are conserved and homologs of ∼75% of human disease-related genes are found in the fruit-fly. Therefore, this model has been used in innovative approaches to evaluate and validate the functional activities of candidate molecules identified via in vitro large-scale analyses, as putative agents to treat or reverse pathological conditions. In this context, Drosophila offers a powerful alternative to investigate the molecular aspects of liver diseases, since no effective therapies are available for those pathologies. Non-alcoholic fatty liver disease is the most common form of chronic hepatic dysfunctions, which may progress to the development of chronic hepatitis and ultimately to cirrhosis, thereby increasing the risk for hepatocellular carcinoma (HCC). This deleterious situation reinforces the use of the Drosophila model to accelerate functional research aimed at deciphering the mechanisms that sustain the disease. In this short review, we illustrate the relevance of using the fruit-fly to address aspects of liver pathologies to contribute to the biomedical area.

Heterozygous variants in ZBTB7A cause a neurodevelopmental disorder associated with symptomatic overgrowth of pharyngeal lymphoid tissue, macrocephaly, and elevated fetal hemoglobin

By clinical whole exome sequencing, we identified 12 individuals with ages 3 to 37 years, including three individuals from the same family, with a consistent phenotype of intellectual disability (ID), macrocephaly, and overgrowth of adenoid tissue. All 12 individuals harbored a rare heterozygous variant in ZBTB7A which encodes the transcription factor Zinc finger and BTB-domain containing protein 7A, known to play a role in lympho- and hematopoiesis. ID was generally mild. Fetal hemoglobin (HbF) fraction was elevated 2.2%-11.2% (reference value <2% in individuals > 6 months) in four of the five individuals for whom results were available. Ten of twelve individuals had undergone surgery at least once for lymphoid hypertrophy limited to the pharynx. In the most severely affected individual (individual 1), airway obstruction resulted in 17 surgical procedures before the age of 13 years. Sleep apnea was present in 8 of 10 individuals. In the nine unrelated individuals, ZBTB7A variants were novel and de novo. The six frameshift/nonsense and four missense variants were spread throughout the gene. This is the first report of a cohort of individuals with this novel syndromic neurodevelopmental disorder.

Drosophila as a Model for Infectious Diseases

The fruit fly, Drosophila melanogaster, has been used to understand fundamental principles of genetics and biology for over a century. Drosophila is now also considered an essential tool to study mechanisms underlying numerous human genetic diseases. In this review, we will discuss how flies can be used to deepen our knowledge of infectious disease mechanisms in vivo. Flies make effective and applicable models for studying host-pathogen interactions thanks to their highly conserved innate immune systems and cellular processes commonly hijacked by pathogens. Drosophila researchers also possess the most powerful, rapid, and versatile tools for genetic manipulation in multicellular organisms. This allows for robust experiments in which specific pathogenic proteins can be expressed either one at a time or in conjunction with each other to dissect the molecular functions of each virulent factor in a cell-type-specific manner. Well documented phenotypes allow large genetic and pharmacological screens to be performed with relative ease using huge collections of mutant and transgenic strains that are publicly available. These factors combine to make Drosophila a powerful tool for dissecting out host-pathogen interactions as well as a tool to better understand how we can treat infectious diseases that pose risks to public health, including COVID-19, caused by SARS-CoV-2.