Biology subjects

Kondo, S.

Publications and source records attributed to Kondo, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Independent size regulation of bones and appendages in zebrafish

During development, organ size and the size of its components must be coordinated. However, the mechanisms integrating these two growth processes remain poorly understood. Here, using the zebrafish fin as a model, we investigated how bioelectric signaling regulates overall appendage size and fin-ray bone segment length. To manipulate bioelectric signaling, we expressed the hyperactive potassium channel mutant kcnk5bW169L or the dominant-negative connexin mutant Cx43T154A under a common set of cell-type-specific promoters. Cell-type-specific bioelectric manipulation in keratinocytes primarily affected fin size, whereas manipulation in osteoblasts preferentially altered fin-ray segment length. Combining these manipulations generated enlarged fins with short segments or small fins with long segments, providing direct evidence that fin size and fin-ray segment length can be regulated independently. Furthermore, optogenetic manipulation demonstrated that membrane potential itself can regulate fin size and fin-ray segment length. Together, these findings reveal that bioelectric signaling can independently regulate appendage growth and skeletal element growth through distinct cellular targets.

developmental biology↗

bioRxiv2024

Hemilineage-specific expression of the RHG genes Grim and Reaper sculpt neural network composition during Drosophila neurogenesis

During development, nervous systems generate an incredible diversity of different cell types. One mechanism that appears critical for controlling whether a specific subtype is present or absent, and ensuring that neuronal numbers are appropriate for specific regions, is programmed cell death. Here we show that the precisely patterned hemilineage-based cell death found in the ventral nerve cord of Drosophila melanogaster is controlled by the transcription of the pro-apoptotic RHG genes reaper and grim. Using smFISH we show that reaper and grim, but not hid, are expressed in postembryonic lineages during neurogenesis. By generating novel T2A-GAL4 knock-in tools we have been able to map reaper and grim expression on a lineage-by-lineage basis and show diverse expression patterns within different hemilineage populations. Analysis of null mutants for both genes reveal a division of labour with distinct combinations being important in sculpting the nervous system. Investigation of a specific sexually dimorphic lineage reveals temporal patterning of hemilineage-specific programmed cell death through Grim and Reaper function underpins the development of sex-specific circuitry in the VNC. Our findings suggest that the precisely patterned expression of these pro-apoptotic genes is a critical fate determinant that generates segmental-specific circuity and instructs the appropriate assembly of sexually dimorphic neural circuits in the VNC.

developmental biology↗

bioRxiv2024

Anti-diuretic hormone ITP signals via a guanylate cyclase receptor to modulate systemic homeostasis in Drosophila

Insects have evolved a variety of neurohormones that enable them to maintain their nutrient and osmotic homeostasis. While the identities and functions of various insect metabolic and diuretic hormones have been well-established, the characterization of an anti-diuretic signaling system that is conserved across most insects is still lacking. To address this, here we characterized the ion transport peptide (ITP) signaling system in Drosophila. The Drosophila ITP gene encodes five transcript variants which generate three different peptide isoforms: ITP amidated (ITPa) and two ITP-like (ITPL1 and ITPL2) isoforms. Using a combination of anatomical mapping and single-cell transcriptome analyses, we comprehensively characterized the expression of all three ITP isoforms in the nervous system and peripheral tissues. Our analyses reveal wide-spread expression of ITP isoforms. Moreover, we show that ITPa-producing neurons are activated and release ITPa during dehydration. Further, recombinant Drosophila ITPa inhibits diuretic peptide-induced renal tubule secretion ex vivo, thus confirming its role as an anti-diuretic hormone. Using a phylogenetic-driven approach, an ex vivo secretion assay and a heterologous mammalian cell-based assay, we identified and functionally characterized Gyc76C, a membrane guanylate cyclase, as a bona fide Drosophila ITPa receptor. Thus, recombinant ITPa application leads to increased cGMP production in HEK293T cells expressing Drosophila Gyc76C. Moreover, knockdown of Gyc76C in renal tubules abolishes the inhibitory effect of ITPa on diuretic hormone stimulated secretion. Extensive anatomical mapping of Gyc76C reveals that it is highly expressed in larval and adult tissues associated with osmoregulation (renal tubules and rectum) and metabolic homeostasis (fat body). Consistent with this expression, knockdown of Gyc76C in renal tubules impacts tolerance to osmotic and ionic stresses, whereas knockdown specifically in the fat body impacts feeding, nutrient homeostasis and associated behaviors. We also complement receptor knockdown experiments with ITP knockdown and ITPa overexpression in ITPa-producing neurons. Interestingly, the ITPa-Gyc76C pathway examined here is reminiscent of the atrial natriuretic peptide signaling in mammals. Lastly, we utilized connectomics and single-cell transcriptomics to identify synaptic and paracrine pathways upstream and downstream of ITPa-expressing neurons. Our analysis identifies pathways via which ITP neurons integrate hygrosensory inputs and interact with other homeostatic hormonal pathways. Taken together, our systematic characterization of ITP signaling establishes a tractable system to decipher how a small set of neurons integrates diverse inputs to orchestrate systemic homeostasis in Drosophila.

physiology↗

bioRxiv2023

Location analysis of presynaptically active and silent synapses in single-cultured hippocampal neurons

A morphologically present but non-functioning synapse is termed a silent synapse. Silent synapses are categorized into "postsynaptically silent synapses," where AMPA receptors are either absent or non-functional, and "presynaptically silent synapses," where neurotransmitters cannot be released from nerve terminals. The presence of presynaptically silent synapses remains enigmatic, and their physiological significance is highly intriguing. In this study, we examined the distribution and developmental changes of presynaptically active and silent synapses in individual neurons. Our findings show a gradual increase in the number of excitatory synapses, along with a corresponding decrease in the percentage of presynaptically silent synapses during neuronal development. To pinpoint the distribution of presynaptically active and silent synapses, i.e., their positional information, we enhanced the traditional Sholl analysis and introduced a novel method termed "donut analysis." Our results indicate that the distribution of presynaptically silent synapses within a single neuron does not exhibit a distinct pattern during synapse development in different areas. However, irrespective of neuronal development, the proportion of presynaptically silent synapses tends to rise as the projection site moves farther from the cell body, suggesting that synapses near the cell body may exhibit higher synaptic transmission efficiency. This study represents the first observation of changes in the distribution of presynaptically active and silent synapses within a single neuron. Additionally, we propose that donut analysis can serve as a valuable analytical tool for evaluating synaptic positional information. Scope statementA morphologically present but non-functioning synapse is termed a silent synapse. The presence of presynaptically silent synapses remains enigmatic, and their physiological significance is highly intriguing. This study focused on the distribution and developmental changes of presynaptically active and silent synapses in individual neurons. To pinpoint the distribution of presynaptically active and silent synapses, we enhanced the traditional Sholl analysis and introduced a novel method termed "donut analysis." We found that the distribution of presynaptically silent synapses within a single neuron does not exhibit a distinct pattern during synapse development in different areas. However, irrespective of neuronal development, the proportion of presynaptically silent synapses tends to rise as the projection site moves farther from the cell body. This is a new paper that applies "Sholl analysis," a method invented 70 years ago that is now the gold standard of morphological analysis of the single neuron. This study represents the first observation of changes in the distribution of presynaptically active and silent synapses within a single neuron. Additionally, we propose that donut analysis can serve as a valuable analytical tool for evaluating synaptic positional information for the design of "synaptic maps" in neural circuits.

neuroscience↗

bioRxiv2023

In Vivo Imaging of Bone Collagen Dynamics in zebrafish

Type I collagen plays a pivotal role in shaping bone morphology and determining its physical properties by serving as a template for ossification. Nevertheless, the mechanisms underlying bone collagen formation, particularly the principles governing its orientation, remain unknown due to the lack of a method enabling continuous in vivo observation. To address this challenge, we constructed a method to visualize bone collagen by tagging with GFP in zebrafish and observed the interactions between the osteoblasts and collagen fiber during bone formation in vivo. When Col1a2-GFP was expressed under the control of the osteoblast-specific promoters osx or osc in zebrafish, bone collagen could be observed clearly enough to identify their localization, but collagen from other organs did not. Therefore, we determined that this method was of sufficient quality for detailed in vivo observation of bone collagen. Next, bone collagen in the scales, fin ray, and opercular bones was observed in detail in zebrafish, when bone formation is more active. By simultaneously observing bone collagen and osteoblasts, we successfully observed dynamic changes in the morphology and position of osteoblasts from the early stages of bone formation. It was also found that the localization pattern and orientation of bone collagen significantly differed depending on the choice of expression promoter. Both promoters (osx and osc) used in this study are osteoblast-specific, but their Col1a2-GFP localizing regions within bone are exclusive, with osx region localizing mainly the outer edge of bone and osc region localizing the central area of bone. This suggests the existence of distinct subpopulations of osteoblasts with various gene expression profiles, each of which may play a unique role in the osteogenic process. These findings would contribute to a better understanding of the mechanisms governing bone collagen formation by osteoblasts.

cell biology↗

bioRxiv2023

Piezo1 Mutant Zebrafish as a Model of Idiopathic Scoliosis

Scoliosis is a condition where the spine curves sideways, unique to humans due to their upright posture. However, the cause of this disease is not well understood because its challenging to find a model for experimentation. This study aimed to create a model for human idiopathic scoliosis by manipulating the function of mechanosensitive channels called Piezo channels in zebrafish. Zebrafish were chosen because they experience similar biomechanical forces to humans, particularly in relation to the role of mechanical force in scoliosis progression. Here we describe piezo1 and piezo2a are involved in bone formation, with a double knockout resulting in congenital systemic malformations. However, an in-frame mutation of piezo1 led to fully penetrant juvenile-onset scoliosis, bone asymmetry, reduced tissue mineral density, and abnormal intervertebral discs-resembling non-congenital scoliosis symptoms in humans. These findings suggest that functional Piezo channels responding to mechanical forces are crucial for bone formation and maintaining spine integrity, providing insights into skeletal disorders.

developmental biology↗

bioRxiv2023

Mettl1-dependent m7G tRNA modification is essential for maintaining spermatogenesis and fertility in Drosophila melanogaster

N7-methylguanosine (m7G) in the variable loop region of tRNA is catalyzed by METTL1/WDR4 heterodimer and stabilizes target tRNA. Here, we reveal essential functions of Mettl1 in Drosophila fertility. Knockout of Mettl1 (Mettl1-KO) lost the elongated spermatids and mature sperm, which was fully rescued by a Mettl1-transgene expression, but not a catalytic-dead Mettl1 transgene. This demonstrates that Mettl1-dependent m7G is required for spermatogenesis. Mettl1-KO resulted in a loss of m7G modification on a subset of tRNAs and a decreased level of tRNA expression. Strikingly, overexpression of the translational elongation factor, EF11, which can compete with the rapid tRNA decay (RTD) pathway in S. cerevisiae, significantly counteracted the sterility of Mettl1-KO males, supporting a critical role of m7G modification of tRNAs in spermatogenesis. Ribosome profiling showed that Mettl1-KO led to the ribosome stalling at codons decoded by tRNAs that were reduced in expression. Mettl1-KO also significantly reduced the translation efficiency of genes involved in elongated spermatid formation and sperm stability. These findings reveal a developmental role for m7G tRNA modifications and indicate that m7G modification-dependent tRNA stability differs among tissues.

molecular biology↗

bioRxiv2023

Visual adaptation of opsin gene expression to the aquatic environment in sea turtles

Several vertebrate taxa, cetaceans, sirenia, pinnipeds, and sea snakes have adapted to the marine aquatic environment. In the species of these taxa, marine adaptation has resulted in shifts in the absorption spectra of opsin pigments and/or the degeneration or duplication of opsin genes. Thus, marine adaptation has strongly affected the evolution of opsins. In sea turtles, however, the effect of adaptation from freshwater to marine environments on opsin evolution has not been studied. In this study, we determined the high-throughput RNA sequences extracted from eyes of two sea turtles (green turtle: Chelonia mydas, loggerhead: Caretta caretta) and two freshwater turtle species (three-keeled pond turtle: Mauremys reevesii, softshell turtle: Pelodiscus sinensis) and investigated the amino acid evolution and expression of the opsin gene. We found that most of the sea turtle lineage-specific amino acid substitutions did not alter amino acid properties and did not include previously known substitutions for turning absorption spectra of opsin pigments, suggesting no adaptive amino acid substitutions in the opsins during marine adaptation in sea turtles. Instead, the blue-sensitive opsin (SWS2) gene expression was higher in sea turtles than in freshwater turtles. These results suggest that sea turtles may have adapted their vision to the blue light-rich marine environment by increasing SWS2 expression.

evolutionary biology↗

bioRxiv2023

Coronin-1 controls directional cell rearrangement in Drosophila wing epithelium

Directional cell rearrangement is a critical process underlying correct tissue deformation during morphogenesis. Although the involvement of F-actin regulation in cell rearrangement has been established, the role and regulation of actin binding proteins (ABPs) in this process are not well understood. In this study, we investigated the function of Coronin-1, a WD-repeat actin-binding protein, in controlling directional cell rearrangement in the Drosophila pupal wing. Transgenic flies expressing Coronin-1-EGFP were generated using CRISPR-Cas9. We observed that Coronin-1 localizes at the reconnecting junction during cell rearrangement, which is dependent on actin interacting protein 1 (AIP1), an actin disassembler and a known regulator of wing cell rearrangement. Loss of Coronin-1 function reduces cell rearrangement directionality and hexagonal cell fraction. These results suggest that Coronin-1 promotes directional cell rearrangement via its interaction with AIP1, highlighting the role of ABPs in the complex process of morphogenesis.

cell biology↗

bioRxiv2023

A humoral stress response protects Drosophila tissues from antimicrobial peptides

The immune response against an invading pathogen is generally associated with collateral tissue damage caused by the immune system itself. Consequently, several resilience mechanisms have evolved to attenuate the negative impacts of immune effectors. Antimicrobial peptides (AMPs) are small, cationic peptides that contribute to innate defenses by targeting negatively charged membranes of microbes1, 2. While being protective against pathogens, AMPs can be cytotoxic to host cells1, 3. Little is known of mechanisms that protect host tissues from AMP-induced immunopathology. Here, we reveal that a family of stress-induced proteins, the Turandots4, 5, protect Drosophila host tissues from AMPs, increasing resilience to stress. Deletion of several Turandot genes increases fly susceptibility to environmental stresses due to trachea apoptosis and poor oxygen supply. Tracheal cell membranes expose high levels of phosphatidylserine, a negatively charged phospholipid, sensitizing them to the action of AMPs. Turandots are secreted from the fat body upon stress and bind to tracheal cells to protect them against AMPs. In vitro, Turandot A binds to phosphatidylserine on membranes and inhibits the pore-forming activity of Drosophila and human AMPs on eukaryotic cells without affecting their microbicidal activity. Collectively, these data demonstrate that Turandot stress proteins mitigate AMP cytotoxicity to host tissues and therefore improve their efficacy. This provides a first example of a humoral mechanism used by animals limiting host-encoded AMP collateral damages.

immunology↗

bioRxiv2023

Translational regulation enhances distinction of cell types in the nervous system

Multicellular organisms are composed of specialized cell types with distinct proteomes. While recent advances in single-cell transcriptome analyses have revealed differential expression of mRNAs, cellular diversity in translational profiles remains underinvestigated. By performing RNA-seq and Ribo-seq in genetically-defined cells in the Drosophila brain, we here revealed substantial posttranscriptional regulations that augment the cell-type distinctions at the level of protein expression. Specifically, we found that translational efficiency of proteins fundamental to neuronal functions, such as ion channels and neurotransmitter receptors, was maintained low in glia, leading to their preferential translation in neurons. Notably, distribution of ribosome footprints on these mRNAs exhibited a remarkable bias towards the 5' leaders in glia. Using transgenic reporter strains, we provide evidence that the small upstream open reading frames (uORFs) in the 5 leader confer selective translational suppression in glia. Overall, these findings underscore the profound impact of translational regulation in shaping the proteomics for cell-type distinction and provide new insights into the molecular mechanisms driving cell-type diversity.

neuroscience↗

bioRxiv2023

Ribosomal protein mutation suppresses gonadal leader cell migration defects in mig-17/ADAMTS mutants in Caenorhabditis elegans

The migration of the gonadal distal tip cells (DTCs) in Caenorhabditis elegans provides an excellent model for studying the migration of epithelial tubes during organogenesis. Mutations in the mig-17/ADAMTS gene cause misdirected migration of DTCs during gonad formation, resulting in deformed gonad arms. An amino-acid substitution in RPL- 20 corresponding to the mammalian RPL18a/eL20, a component of the 60S ribosomal large subunit, showed a slow growth phenotype and strongly suppressed the mig-17 gonadal defects. Slow-growing mutants clk-1 and clk-2 also suppressed mig-17, although weaker than rlp-20 mutants. MIG-17 recruits FBL-1C/fibulin-1C to the gonadal basement membrane to regulate DTC migration. Reducing the gene dosage of fbl-1 by half partially compromised the suppressor activity of the mutant rpl-20 gene on mig-17. Analysis using the mNeonGreen-FBL-1 reporter revealed that its localization to the gonadal basement membrane was significantly reduced in mig-17, whereas it was recovered to the wild-type levels in mig-17; rpl-20 double mutants. These results indicate that the rpl-20 mutation suppresses mig-17 gonadal defects through dual mechanisms: deceleration of growth rate and enhancement of FBL-1C recruitment to the gonadal basement membrane.

developmental biology↗

bioRxiv2023

Mechanical models affecting beetle horn remodeling

Clarifying the mechanisms of shape alteration by insect metamorphosis is important for comprehending exoskeletal morphogenesis. The large horn of the Japanese rhinoceros beetle Trypoxylus dichotomus is the result of drastic metamorphosis, wherein it appears as a rounded shape via pupation and then undergoes remodeling into an angular adult shape. However, the mechanical mechanisms of this remodeling process remain unknown. In this study, we investigated the remodeling mechanisms of the Japanese rhinoceros beetle horn by developing a physical simulation. We identified three factors contributing to remodeling by biological experiments--ventral adhesion, uneven shrinkage, and volume reduction--which were demonstrated to be crucial to the transformation by a physical simulation. We also corroborated our findings by applying the simulation to the stag beetles mandibular remodeling. These results indicate that the physical simulation is applicable to pupal remodeling in other beetles, and the morphogenic mechanisms could explain various exoskeletal shapes. Significance statementThe metamorphosis in insects is a mysterious process. By metamorphosis, insects sometimes change their shape dramatically. The head horn of the Japanese rhinoceros beetle is one of the most famous examples of metamorphosis. In larva-to-pupa molting, the horn appears suddenly, caused by the "furrow formation and unfolding" mechanism. The unfolding process makes the pupal horn rounded. However, pupa-to-adult molting transforms the rounded shape into an angular shape. In this paper, we investigated the mechanisms of the transformation. We extracted factors contributing to it through observations and experiments and developed a physical simulation. It could reproduce the adult shape from the pupal shape and could be a general model for the pupa-adult transformation of beetles.

developmental biology↗

bioRxiv2022

Tackling Mitosis Domain Generalization in Histopathology Images with Color Normalization

In this report, we propose a method for mitosis detection in histopathology images of MIDOG2022 challenge dataset. Our method is based on unsupervised domain adaptation at inputlevel, and a combination of color normalization and object detection. We evaluate our method by using the preliminary test set including 20 cases and obtain 0.716 F1 score.

bioengineering↗

bioRxiv2022

Female reproductive dormancy in Drosophila melanogaster is regulated by DH31-producing neurons projecting into the corpus allatum

Female reproductive dormancy in insects is a process that drastically suppresses oogenesis to conserve energy under adverse environments. In many insects, including the fruit fly, Drosophila melanogaster, reproductive dormancy is induced under low-temperature and short-day conditions by the downregulation of juvenile hormone (JH) biosynthesis by the corpus allatum (CA). Previous studies have suggested that brain neurons that project directly to the CA are important for the regulation of reproductive dormancy. However, the role of CA-projecting neurons in JH-mediated reproductive dormancy has not yet been confirmed by molecular genetic studies. In this study, we report that, in adult D. melanogaster, the neuropeptide diuretic hormone 31 (DH31) is produced by brain neurons that project into the CA. DH31-producing-CA-projecting neurons are connected downstream with a subset of circadian clock neurons, such as s-LNvs, which are known to be involved in reproductive dormancy regulation. The CA expresses the gene encoding the DH31 receptor, which is required for DH31-triggered elevation of intracellular cAMP in the CA. Knocking down Dh31 in these CA-projecting neurons or DH31 receptor in the CA leads to a failure in the decrease of the JH titer, normally observed under dormancy-inducing conditions, leading to abnormal yolk accumulation in the ovaries. Our findings provide the first molecular genetic evidence demonstrating that CA-projecting peptidergic neurons play an essential role in regulating reproductive dormancy by suppressing JH biosynthesis. Significance StatementDormancy is an adaptive physiological response to environmental changes that are unsuitable for survival. Adult females of many insect species undergo reproductive dormancy in which oogenesis is drastically arrested; it is induced by a decrease in juvenile hormone (JH) titers. However, we are yet to fully understand the molecular mechanisms underlying the control of JH biosynthesis under dormancy-inducing conditions. In this study using the fruit fly, we demonstrated that brain neurons projecting directly to the JH-producing organ, corpus allatum, play an essential role in regulating reproductive dormancy via the neuropeptide DH31. As the morphologically-similar neurons have previously been suggested to be involved in reproductive dormancy regulation, this study provides a fundamental molecular and neuronal basis for reproductive dormancy in insects.

physiology↗

bioRxiv2022

Molecular and functional characterization of the Drosophila melanogaster conserved smORFome

Short polypeptides encoded by small open reading frames (smORFs) are ubiquitously found in eukaryotic genomes and are important regulators of physiology, development, and mitochondrial processes. Here, we focus on a subset of 298 smORFs that are evolutionarily conserved between Drosophila melanogaster and humans. Many of these smORFs are conserved broadly in the bilaterian lineage, with [~]182 conserved in plants. Within these conserved smORFs, we observed remarkably heterogenous spatial and temporal expression patterns - indicating wide-spread tissue-specific and stage-specific mitochondrial architectures. In addition, an analysis of annotated functional domains revealed a predicted enrichment of smORF polypeptides localizing to mitochondria. We conducted an embryonic ribosome profiling experiment finding support for translation of 137 of these smORFs during embryogenesis. We further embarked on functional characterization using CRISPR knockout/activation, RNAi knockdown, and cDNA overexpression, revealing diverse phenotypes. This study underscores the importance of identifying smORF function in disease and phenotypic diversity.

genomics↗

bioRxiv2022

Drosophila immunity: The Drosocin gene encodes two host defence peptides with pathogen-specific roles

1.1Antimicrobial peptides (AMPs) are key players in innate defence against infection in plants and animals. In Drosophila, many host defence peptides are produced downstream of the Toll and Imd NF-{kappa}B pathways. Use of single and compound AMP mutations in Drosophila has revealed that AMPs can additively or synergistically contribute to combat pathogens in vivo. However, these studies also revealed a high degree of specificity, wherein just one AMP can play a major role in combatting a specific pathogen. We recently uncovered a specific importance of the antibacterial peptide Drosocin for defence against Enterobacter cloacae. Here, we show that the Drosocin locus (CG10816) is more complex than previously described. In addition to its namesake peptide "Drosocin", it encodes a second peptide generated from a precursor via furin cleavage. We name this peptide "Buletin", and show that it corresponds to the uncharacterized "Immune-induced Molecule 7" previously identified by MALDI-TOF. The existence of a naturally occurring polymorphism (Thr52Ala) in the CG10816 precursor protein masked the identification of this peptide previously. Using mutations differently affecting the production of these two CG10816 gene products, we show that Drosocin, but not Buletin, contributes to the CG10816-mediated defence against E. cloacae. Strikingly, we observed that Buletin, but not Drosocin, contributes to the CG10816-mediated defence against Providencia burhodogranariea. Moreover, the Thr52Ala polymorphism in Buletin affects survival to P. burhodogranariea, wherein the Alanine allele confers better defence than the Threonine allele. However, we found no activity of Buletin against either P. burhodogranariea or E. coli in vitro. Collectively, our study reveals that CG10816 encodes not one but two prominent host defence peptides with different specificity against different pathogens. This finding emphasizes the complexity of the Drosophila humoral response consisting of multiple host defence peptides with specific activities, and demonstrates how natural polymorphisms found in Drosophila populations can affect host susceptibility.

immunology↗

bioRxiv2022

A descending inhibitory mechanism of nociception mediated by an evolutionarily conserved neuropeptide system in Drosophila

Nociception is a neural process that animals have developed to avoid potentially tissue-damaging stimuli. While nociception is triggered in the peripheral nervous system, its modulation by the central nervous system is a critical process in mammals, whose dysfunction has been extensively implicated in chronic pain pathogenesis. The peripheral mechanisms of nociception are largely conserved across the animal kingdom. However, it is unclear whether the brain-mediated modulation is also conserved in non-mammalian species. Here, we show that Drosophila has a descending inhibitory mechanism of nociception from the brain, mediated by the neuropeptide Drosulfakinin (DSK), a homolog of cholecystokinin (CCK) that plays an important role in the descending control of nociception in mammals. We found that mutants lacking dsk or its receptors are hypersensitive to noxious heat. Through a combination of genetic, behavioral, histological, and Ca2+ imaging analyses, we subsequently revealed neurons involved in DSK-mediated nociceptive regulation at a single-cell resolution and identified a DSKergic descending neuronal pathway that inhibits nociception. This study provides the first evidence for a descending modulatory mechanism of nociception from the brain in a non-mammalian species that is mediated by the evolutionarily conserved CCK system, raising the possibility that the descending inhibition is an ancient mechanism to regulate nociception.

neuroscience↗