Galectins induced from hemocytes bridge phosphatidylserine and N-glycosylated Drpr/CED-1 receptor during dendrite pruning.

During neuronal pruning, phagocytes engulf shed cellular debris to avoid inflammation and maintain tissue homeostasis. How phagocytic receptors recognize degenerating neurites had been unclear. Here, we identify two glucosyltransferases Alg8 and Alg10 of the N-glycosylation pathway required for dendrite fragmentation and clearance through genetic screen. The scavenger receptor Draper (Drpr) is N-glycosylated with complex- or hybrid-type N-glycans that interact specifically with galectins. We also identify the galectins Crouching tiger (Ctg) and Hidden dragon (Hdg) that interact with N-glycosylated Drpr and function in dendrite pruning via the Drpr pathway. Ctg and Hdg are required in hemocytes for expression and function, and are induced during dendrite injury to localize to injured dendrites through specific interaction with exposed phosphatidylserine (PS) on the surface membrane of injured dendrites. Thus, the galectins Ctg and Hdg bridge the interaction between PS and N-glycosylated Drpr, leading to the activation of phagocytosis.

Are the tumor microenvironment characteristics of pretreatment biopsy specimens of colorectal cancer really effectively predict the efficacy of neoadjuvant therapy: A retrospective multicenter study.

More and more studies had pointed out that the tumor microenvironment characteristics based on colorectal cancer (CRC) pretreatment biopsy specimens could effectively predict the efficacy of neoadjuvant therapy, but under hematoxylin and eosin (HE) staining, whether the tumor microenvironment characteristics observed by pathologists could predict the efficacy of neoadjuvant therapy remains to be discussed. We collected 106 CRC patients who received neoadjuvant treatment and surgical resection from 3 hospitals. The number of mitosis, inflammation degree, desmoplastic reaction (DR), necrosis, tumor-stroma ratio (TSR) and tumor budding (TB) of CRC pretreatment biopsy specimens were observed under HE staining, and the degree of tumor pathological remission of CRC surgical specimens after neoadjuvant treatment was evaluated. According to the tumor regression grade (TRG), patients were divided into good-responders (TRG 0-1) and non-responders (TRG 2-3). All data were analyzed with SPSS software (version 23.0) to evaluate the correlation between the number of mitosis, inflammation degree, DR, necrosis, TSR and TB in pretreatment biopsy samples and the treatment effect. In univariate analysis, mitosis (P = .442), inflammation degree (P = .951), DR (P = .186), necrosis (P = .306), TSR (P = .672), and TB (P = .327) were not associated with the response to neoadjuvant therapy. However, we found that for colon cancer, rectal cancer was more likely to benefit from neoadjuvant therapy (P = .024). In addition, we further analyzed the impact of mitosis, inflammation degree, DR, necrosis, TSR and TB on neoadjuvant therapy in rectal cancer, and found that there was no predictive effect. By analyzing the characteristics of tumor microenvironment of CRC pretreatment biopsy specimens under HE staining, such as mitosis, inflammation degree, DR, necrosis, TSR and TB, it was impossible to effectively predict the efficacy of neoadjuvant therapy for CRC.

State-specific Regulation of Electrical Stimulation in the Intralaminar Thalamus of Macaque Monkeys: Network and Transcriptional Insights into Arousal.

Long-range thalamocortical communication is central to anesthesia-induced loss of consciousness and its reversal. However, isolating the specific neural networks connecting thalamic nuclei with various cortical regions for state-specific anesthesia regulation is challenging, with the biological underpinnings still largely unknown. Here, simultaneous electroencephalogram-fuctional magnetic resonance imaging (EEG-fMRI) and deep brain stimulation are applied to the intralaminar thalamus in macaques under finely-tuned propofol anesthesia. This approach led to the identification of an intralaminar-driven network responsible for rapid arousal during slow-wave oscillations. A network-based RNA-sequencing analysis is conducted of region-, layer-, and cell-specific gene expression data from independent transcriptomic atlases and identifies 2489 genes preferentially expressed within this arousal network, notably enriched in potassium channels and excitatory, parvalbumin-expressing neurons, and oligodendrocytes. Comparison with human RNA-sequencing data highlights conserved molecular and cellular architectures that enable the matching of homologous genes, protein interactions, and cell types across primates, providing novel insight into network-focused transcriptional signatures of arousal.

Chronotoxici-Plate Containing Droplet-Engineered Rhythmic Liver Organoids for Drug Toxicity Evaluation.

The circadian clock coordinates the daily rhythmicity of biological processes, and its dysregulation is associated with various human diseases. Despite the direct targeting of rhythmic genes by many prevalent and World Health Organization (WHO) essential drugs, traditional approaches can't satisfy the need of explore multi-timepoint drug administration strategies across a wide range of drugs. Here, droplet-engineered primary liver organoids (DPLOs) are generated with rhythmic characteristics in 4 days, and developed Chronotoxici-plate as an in vitro high-throughput automated rhythmic tool for chronotherapy assessment within 7 days. Cryptochrome 1 (Cry1) is identified as a rhythmic marker in DPLOs, providing insights for rapid assessment of organoid rhythmicity. Using oxaliplatin as a representative drug, time-dependent variations are demonstrated in toxicity on the Chronotoxici-plate, highlighting the importance of considering time-dependent effects. Additionally, the role of chronobiology is underscored in primary organoid modeling. This study may provide tools for both precision chronotherapy and chronotoxicity in drug development by optimizing administration timing.

EGFR signaling controls directionality of epithelial multilayer formation upon loss of cell polarity.

Apical-basal polarity is maintained by distinct protein complexes that reside in membrane junctions, and polarity loss in monolayered epithelial cells can lead to formation of multilayers, cell extrusion, and/or malignant overgrowth. Yet, how polarity loss cooperates with intrinsic signals to control directional invasion toward neighboring epithelial cells remains elusive. Using the Drosophila ovarian follicular epithelium as a model, we found that posterior follicle cells with loss of lethal giant larvae (lgl) or Discs large (Dlg) accumulate apically toward germline cells, whereas cells with loss of Bazooka (Baz) or atypical protein kinase C (aPKC) expand toward the basal side of wildtype neighbors. Further studies revealed that these distinct multilayering patterns in the follicular epithelium were determined by epidermal growth factor receptor (EGFR) signaling and its downstream target Pointed, a zinc-finger transcription factor. Additionally, we identified Rho kinase as a Pointed target that regulates formation of distinct multilayering patterns. These findings provide insight into how cell polarity genes and receptor tyrosine kinase signaling interact to govern epithelial cell organization and directional growth that contribute to epithelial tumor formation.

Controllable Star Cationic Poly(Disulfide)s Achieve Genetically Cascade Catalytic Therapy by Delivering Bifunctional Fusion Plasmids.

The absence of effective delivery vectors and suitable multifunctional plasmids limits cancer gene therapy development. The star cationic poly(disulfide)s with ß-cyclodextrin cores (termed ß-CD-g-PSSn ) for caveolae-mediated endocytosis are designed and prepared via mild and controllable disulfide exchange polymerization for high-efficacy cancer therapy. Then, ß-CD-g-PSSn /pDNA complexes are transported to the Golgi apparatus and endoplasmic reticulum. Disulfides in ß-CD-g-PSSn vectors are degraded by glutathione in tumor cells, which not only promotes intracellular pDNA release but also reduces in vitro and in vivo toxicity. One bifunctional fusion plasmid pCATKR, which expresses catalase (CAT) fused to KillerRed (KR) (CATKR) in the same target cell, is also proposed for genetically cascade catalytic therapy. When compared with pCAT-KR (plasmid expressing CAT and KR separately in the same cell), delivered pCATKR decomposes hydrogen peroxide, alleviates tumor hypoxia more effectively, generates stronger reactive oxygen species (ROS) capabilities under moderate irradiation, and leads to robust antitumor cascade photodynamic effects. These impressive results are attributed to fusion protein design, which shortens the distance between CAT and KR catalytic centers and leads to improved ROS production efficiency. This work provides a promising strategy by delivering a catalytic cascade functional plasmid via a high-performance vector with biodegradable and caveolae-mediated endocytosis characteristics.

The CHCHD2/Sirt1 corepressors involve in G9a-mediated regulation of RNase H1 expression to control R-loop.

R-loops are regulators of many cellular processes and are threats to genome integrity. Therefore, understanding the mechanisms underlying the regulation of R-loops is important. Inspired by the findings on RNase H1-mediated R-loop degradation or accumulation, we focused our interest on the regulation of RNase H1 expression. In the present study, we report that G9a positively regulates RNase H1 expression to boost R-loop degradation. CHCHD2 acts as a repressive transcription factor that inhibits the expression of RNase H1 to promote R-loop accumulation. Sirt1 interacts with CHCHD2 and deacetylates it, which functions as a corepressor that suppresses the expression of downstream target gene RNase H1. We also found that G9a methylated the promoter of RNase H1, inhibiting the binding of CHCHD2 and Sirt1. In contrast, when G9a was knocked down, recruitment of CHCHD2 and Sirt1 to the RNase H1 promoter increased, which co-inhibited RNase H1 transcription. Furthermore, knockdown of Sirt1 led to binding of G9a to the RNase H1 promoter. In summary, we demonstrated that G9a regulates RNase H1 expression to maintain the steady-state balance of R-loops by suppressing the recruitment of CHCHD2/Sirt1 corepressors to the target gene promoter.

Integrating lipid metabolism, pheromone production and perception by Fruitless and Hepatocyte Nuclear Factor 4.

Sexual attraction and perception are crucial for mating and reproductive success. In Drosophila melanogaster, the male-specific isoform of Fruitless (Fru), FruM, is a known master neuro-regulator of innate courtship behavior to control the perception of sex pheromones in sensory neurons. Here, we show that the non-sex-specific Fru isoform (FruCOM) is necessary for pheromone biosynthesis in hepatocyte-like oenocytes for sexual attraction. Loss of FruCOM in oenocytes resulted in adults with reduced levels of cuticular hydrocarbons (CHCs), including sex pheromones, and show altered sexual attraction and reduced cuticular hydrophobicity. We further identify Hepatocyte nuclear factor 4 (Hnf4) as a key target of FruCOM in directing fatty acid conversion to hydrocarbons. Fru or Hnf4 depletion in oenocytes disrupts lipid homeostasis, resulting in a sex-dimorphic CHC profile that differs from doublesex- and transformer-dependent CHC dimorphism. Thus, Fru couples pheromone perception and production in separate organs to regulate chemosensory communications and ensure efficient mating behavior.

Integrating lipid metabolism, pheromone production and perception by Fruitless and Hepatocyte nuclear factor 4.

Sexual attraction and perception, governed by separate genetic circuits in different organs, are crucial for mating and reproductive success, yet the mechanisms of how these two aspects are integrated remain unclear. In Drosophila , the male-specific isoform of Fruitless (Fru), Fru M , is known as a master neuro-regulator of innate courtship behavior to control perception of sex pheromones in sensory neurons. Here we show that the non-sex specific Fru isoform (Fru COM ) is necessary for pheromone biosynthesis in hepatocyte-like oenocytes for sexual attraction. Loss of Fru COM in oenocytes resulted in adults with reduced levels of the cuticular hydrocarbons (CHCs), including sex pheromones, and show altered sexual attraction and reduced cuticular hydrophobicity. We further identify Hepatocyte nuclear factor 4 ( Hnf4 ) as a key target of Fru COM in directing fatty acid conversion to hydrocarbons in adult oenocytes. fru - and Hnf4 -depletion disrupts lipid homeostasis, resulting in a novel sex-dimorphic CHC profile, which differs from doublesex - and transformer -dependent sexual dimorphism of the CHC profile. Thus, Fru couples pheromone perception and production in separate organs for precise coordination of chemosensory communication that ensures efficient mating behavior. Teaser: Fruitless and lipid metabolism regulator HNF4 integrate pheromone biosynthesis and perception to ensure robust courtship behavior.

Excessive consumption of mucin by over-colonized Akkermansia muciniphila promotes intestinal barrier damage during malignant intestinal environment.

Gut microbiota disorders damage the intestinal barrier, which causes intestinal disease. Thus, we screened the microbiota with significant changes using an in situ malignant colorectal cancer (CRC) model. Among the colonies with increased abundance, Akkermansia muciniphila (A. muciniphila) is known for its characteristic of breaking down mucin, which is an essential component of the intestinal barrier. The role of A. muciniphila remains controversial. To investigate the effect of excess A. muciniphila on the intestinal barrier, we established an over-colonized A. muciniphila mouse model by administering a live bacterial suspension after disrupting the original gut microbiome with antibiotics. The results showed that over-colonization of A. muciniphila decreased intestinal mucin content. The mRNA and protein expression levels of tight junction proteins also decreased significantly in the over-colonized A. muciniphila mouse model. Our findings reveal that excess colonization by A. muciniphila breaks the dynamic balance between mucin secretion and degradation, reduces the thickness of the intestinal mucus layer, and damages the intestinal barrier, which would eventually aggravate the development of colitis and CRC. These results will raise awareness about the safety of A. muciniphila serving as a probiotic.

Immunomodulatory and antiviral effects of Lycium barbarum glycopeptide on influenza a virus infection.

Influenza is caused by a respiratory virus and has a major global impact on human health. Influenza A viruses in particular are highly pathogenic to humans and have caused multiple pandemics. An important consequence of infection is viral pneumonia, and with serious complications of excessive inflammation and tissue damage. Therefore, simultaneously reducing direct damage caused by virus infection and relieving indirect damage caused by excessive inflammation would be an effective treatment strategy. Lycium barbarum glycopeptide (LbGp) is a mixture of five highly branched polysaccharide-protein conjuncts (LbGp1-5) isolated from Lycium barbarum fruit. LbGp has pro-immune activity that is 1-2 orders of magnitude stronger than that of other plant polysaccharides. However, there are few reports on the immunomodulatory and antiviral activities of LbGp. In this study, we evaluated the antiviral and immunomodulatory effects of LbGp in vivo and in vitro and investigated its therapeutic effect on H1N1-induced viral pneumonia and mechanisms of action. In vitro, cytokine secretion, NF-κB p65 nuclear translocation, and CD86 mRNA expression in LPS-stimulated RAW264.7 cells were constrained by LbGp treatment. In A549 cells, LbGp can inhibit H1N1 infection by blocking virus attachment and entry action. In vivo experiments confirmed that administration of LbGp can effectively increase the survival rate, body weight and decrease the lung index of mice infected with H1N1. Compared to the model group, pulmonary histopathologic symptoms in lung sections of mice treated with LbGp were obviously alleviated. Further investigation revealed that the mechanism of LbGp in the treatment of H1N1-induced viral pneumonia includes reducing the viral load in lung, regulating the phenotype of pulmonary macrophages, and inhibiting excessive inflammation. In conclusion, LbGp exhibits potential curative effects against H1N1-induced viral pneumonia in mice, and these effects are associated with its good immuno-regulatory and antiviral activities.

Effects of Shared Decision-Making with a Patient Decision Aid for Postangiography Hemostasis Method Selection: A Randomized Controlled Trial.

PURPOSE: To evaluate the effects of shared decision-making (SDM) with a patient decision aid (PtDA) on hemostasis device selection and reduction of decisional conflicts in patients undergoing transfemoral angiography. MATERIALS AND METHODS: Patients undergoing angiography were randomized to receive either a standard explanation or the process aid of PtDA for choosing hemostasis devices. The decisional conflict was assessed using the 4-item Sure of myself; Understand information; Risk-benefit ratio; Encouragement (SURE) scale. Differences in demographic variables, clinical variables, and final choice of hemostasis devices were compared via univariate and multivariate logistic regression analyses. RESULTS: In total, 158 patients were included-80 in the PtDA group and 78 in the standard group. No difference was found between the 2 groups in terms of patient demographic and clinical variables. The PtDA group scored better on all questions of the SURE scale both individually and collaboratively (P <.001). PtDA intervention (P =.031) and reason for angiography (P =.0006) were the main variables that influenced patient hemostasis device choice in the univariate logistic regression analysis. Reason for angiography remained the only deciding factor that affected patient choice in the multivariate logistic regression analysis (P =.015). CONCLUSIONS: Step-by-step guidance and pictorial explanation with the assistance of PtDA led to improvements in patient knowledge but showed no significant impact in multivariate analysis for the influence on the choice of hemostasis device.

Cell polarity opposes Jak/STAT-mediated Escargot activation that drives intratumor heterogeneity in a Drosophila tumor model.

In proliferating neoplasms, microenvironment-derived selective pressures promote tumor heterogeneity by imparting diverse capacities for growth, differentiation, and invasion. However, what makes a tumor cell respond to signaling cues differently from a normal cell is not well understood. In the Drosophila ovarian follicle cells, apicobasal-polarity loss induces heterogeneous epithelial multilayering. When exacerbated by oncogenic-Notch expression, this multilayer displays an increased consistency in the occurrence of morphologically distinguishable cells adjacent to the polar follicle cells. Polar cells release the Jak/STAT ligand Unpaired (Upd), in response to which neighboring polarity-deficient cells exhibit a precursor-like transcriptomic state. Among the several regulons active in these cells, we could detect and further validate the expression of Snail family transcription factor Escargot (Esg). We also ascertain a similar relationship between Upd and Esg in normally developing ovaries, where establishment of polarity determines early follicular differentiation. Overall, our results indicate that epithelial-cell polarity acts as a gatekeeper against microenvironmental selective pressures that drive heterogeneity.

Association of Echocardiographic Parameter E/e' With Cardiovascular Events in a Diverse Population of Inpatients and Outpatients With and Without Cardiac Diseases and Risk Factors.

BACKGROUND: The echocardiographic parameter E/e' has been associated with cardiovascular (CV) events. However, few studies have analyzed multiple associated CV outcomes using E/e' in a diverse population of both inpatients and outpatients with and without cardiac diseases and risk factors. METHODS: Medical records of 75,393 patients without atrial fibrillation (AF) with first available E/e' were retrieved from our hospital database. Patients with mitral valve disease were excluded, and the remainder were studied in protocol 1 (70,819 patients). Patients with hypertension, diabetes mellitus, hyperlipidemia, CV diseases, prior CV events, CV surgeries, and left ventricular ejection fraction <50% or missing left ventricular ejection fraction were further excluded, and the remaining patients were studied in protocol 2 (14,665 patients). The study outcomes are major adverse CV events (MACE), which included myocardial infarction (MI), AF, ischemic and hemorrhagic stroke (IHS), hospitalization for heart failure (HHF), and cardiac death. The primary outcomes were MACE and each of the MACE components. RESULTS: At the end of maximal 5-year follow-up (median 22.18 months with interquartile range 7.20-49.08 months for MACE in protocol 1 and 23.46 months with interquartile range 8.15-49.02 months for MACE in protocol 2), compared with an E/e' value of <8, an intermediate value of E/e' 8 to 15 and a high value of E/e' >15 were significantly associated with MACE, MI, AF, IHS, HHF, and cardiac death in protocol 1 (all P < .0001). In protocol 2, an intermediate E/e' value of 8 to 15 and a high value of E/e' >15 were significantly associated with MACE, MI, AF, IHS, HHF, and CV death (all P < .05), except an intermediate value E/e' 8 to 15 was not associated with AF. CONCLUSIONS: In a diverse population of inpatients and outpatients with and without cardiac diseases and risk factors, the echocardiographic parameter E/e' was associated with CV events and is a useful marker of risk.

Atrial Fibrillation in Adult Congenital Heart Increase Ischemic Stroke Risk Even at Low CHA2DS2-VASc Score.

Background: The population of adults with congenital heart diseases (ACHDs) is expanding, and atrial fibrillation (AF) emerges as a crucial risk factor for ischemic stroke. However, the evidence regarding the impact of AF on the incidence of ischemic stroke in ACHDs remains limited. In this study, we aimed to investigate the prevalence and effect of AF among ACHDs and assess the suitability of the traditional CHA2DS2-VASc score in this specific population. Methods: Data of ACHDs from 2000 to 2010 were retrospectively collected from the Taiwan National Health Insurance Research Database. We divided ACHDs into those with and without AF, and ischemic stroke incidence was studied among ACHD subtypes and those who received anticoagulant therapy with warfarin or not according to CHA2DS2-VASc score. Results: 36,530 ACHDs were retrieved from the database. ACHDs had a 4.7-15.3 times higher AF risk than did the general population, which varied based on the age group. ACHDs with AF had 1.45 times higher ischemic stroke risk than those without AF (p = 0.009). Ischemic stroke incidence among ACHDs with AF aged < 50 years was 1.46 times higher than those without AF (p = 0.207). Ischemic stroke incidence was over 1.47% even in those with a low CHA2DS2-VASc score (0-1) with or without anticoagulant therapy. Conclusions: During the 12-year follow-up, ACHDs with AF were found to have an increased risk of ischemic stroke. The ischemic stroke incidence was high, even in those with a low CHA2DS2-VASc score (0-1).

Corrigendum: Lycium barbarum Glycopeptide prevents the development and progression of acute colitis by regulating the composition and diversity of the gut microbiota in mice.

[This corrects the article DOI: 10.3389/fcimb.2022.921075.].

Single-cell transcriptomics identifies Keap1-Nrf2 regulated collective invasion in a Drosophila tumor model.

Apicobasal cell polarity loss is a founding event in epithelial-mesenchymal transition and epithelial tumorigenesis, yet how pathological polarity loss links to plasticity remains largely unknown. To understand the mechanisms and mediators regulating plasticity upon polarity loss, we performed single-cell RNA sequencing of Drosophila ovaries, where inducing polarity-gene l(2)gl-knockdown (Lgl-KD) causes invasive multilayering of the follicular epithelia. Analyzing the integrated Lgl-KD and wildtype transcriptomes, we discovered the cells specific to the various discernible phenotypes and characterized the underlying gene expression. A genetic requirement of Keap1-Nrf2 signaling in promoting multilayer formation of Lgl-KD cells was further identified. Ectopic expression of Keap1 increased the volume of delaminated follicle cells that showed enhanced invasive behavior with significant changes to the cytoskeleton. Overall, our findings describe the comprehensive transcriptome of cells within the follicle cell tumor model at the single-cell resolution and identify a previously unappreciated link between Keap1-Nrf2 signaling and cell plasticity at early tumorigenesis.

In the body, most cells exhibit some form of spatial asymmetry: the compartments within the cell are not evenly distributed, thereby allowing the cells to know whether a surface is on the 'outside' or the 'inside' of a tissue or organ. In the cells of epithelial tissues, which line most of the cavities and the organs in the body, this asymmetry is known as apical-basal polarity. Maintaining apical-basal polarity in epithelial cells is one of the main barriers that stops cancer cells from invading other tissues, which is the first step of metastasis, the process through which cancer cells leave their tissue of our origin and spread to distant locations in the body. In the fruit fly Drosophila melanogaster, scientists have engineered cells in several tissues to stop producing the proteins that help establish apical-basal polarity, in an effort to study the earliest steps of tumor formation. Unfortunately, these experiments frequently lead to rampant metastasis, making it difficult to identify the earliest changes that make the tumor cells more likely to become invasive. Therefore, finding a tissue in which loss of apical-basal polarity does not cause aggressive cancer progression is necessary to address this gap in knowledge. The epithelial cell layer lining the ovaries of fruit flies may be such a tissue. When these cells lose their apical-basal polarity, rather than becoming metastatic and spreading to distant organs, they interleave with each other, forming a tumorous growth that only invades into the neighboring compartment. Chatterjee et al. used this system to study individual invasive cells. They wanted to know whether the genes that these cells switch on and off are known to be involved in human cancers, and if so, which of them control the invasive behavior of tumor cells. Chatterjee et al. determined that when cells in the fruit-fly ovary lost their polarity, they turned genes on and off in a pattern similar to that seen both in mammalian cancers and in tumors from other fly tissues. One of the notable changes they observed in the ovarian cells that lost apical-basal polarity was the activation of the Keap1/Nrf2 oxidative-stress signaling pathway, which normally protects cells from damage caused by excessive oxidation. In the ovarian cells, however, the activation of these genes also led to aggressive invasion of the collective tumor cells into the neighboring compartment. Interestingly, this increase in invasiveness was characterized by polarized changes within the cells, specifically in the scaffolding that allows cells to keep their shape and move: the edge of the cells leading the invasion had greater levels of a protein called actin, which enables the cells to protrude into the neighboring compartments. Chatterjee et al. have identified a new mechanism that impacts the migratory behavior of cells. Insights from their findings will pave the way for a better understanding of how and when this mechanism plays a role in metastasis.

Developmental regulation of epithelial cell cuboidal-to-squamous transition in Drosophila follicle cells.

Epithelial cells form continuous membranous structures for organ formation, and these cells are classified into three major morphological categories: cuboidal, columnar, and squamous. It is crucial that cells transition between these shapes during the morphogenetic events of organogenesis, yet this process remains poorly understood. All three epithelial cell shapes can be found in the follicular epithelium of Drosophila egg chamber during oogenesis. Squamous cells (SCs) are initially restricted to the anterior terminus in cuboidal shape. They then rapidly become flattened to assume squamous shape by stretching and expansion in 12 â€‹h during midoogenesis. Previously, we reported that Notch signaling activated a zinc-finger transcription factor Broad (Br) at the end of early oogenesis. Here we report that ecdysone and JAK/STAT pathways subsequently converge on Br to serve as an important spatiotemporal regulator of this dramatic morphological change of SCs. The early uniform pattern of Br in the follicular epithelium is directly established by Notch signaling at stage 5 of oogenesis. Later, ecdysone and JAK/STAT signaling activities synergize to suppress Br in SCs from stage 8 to 10a, contributing to proper SC squamous shape. During this process, ecdysone signaling is essential for SC stretching, while JAK/STAT regulates SC clustering and cell fate determination. This study reveals an inhibitory role of ecdysone signaling in suppressing Br in epithelial cell remodeling. In this study we also used single-cell RNA sequencing data to highlight the shift in gene expression which occurs as Br is suppressed and cells become flattened.

Fringe-positive Golgi outposts unite temporal Furin 2 convertase activity and spatial Delta signal to promote dendritic branch retraction.

Golgi outposts (GOPs) in dendrites are known for their role in promoting branch extension, but whether GOPs have other functions is unclear. We found that terminal branches of Drosophila class IV dendritic arborization (C4da) neurons actively grow during the early third-instar (E3) larval stage but retract in the late third (L3) stage. Interestingly, the Fringe (Fng) glycosyltransferase localizes increasingly at GOPs in distal dendritic regions through the E3 to the L3 stage. Expression of the endopeptidase Furin 2 (Fur2), which proteolyzes and inactivates Fng, decreases from E3 to L3 in C4da neurons, thereby increasing Fng-positive GOPs in dendrites. The epidermal Delta ligand and neuronal Notch receptor, the substrate for Fng-mediated O-glycosylation, also negatively regulate dendrite growth. Fng inhibits actin dynamics in dendrites, linking dendritic branch retraction to suppression of the C4da-mediated thermal nociception response in late larval stages. Thus, Fng-positive GOPs function in dendrite retraction, which would add another function to the repertoire of GOPs in dendrite arborization.