Immune cells elicit a continuum of transcriptional and functional states after spinal cord injury (SCI). In mammals, inefficient debris clearance and chronic inflammation impede recovery and overshadow pro-regenerative immune functions. We found that, unlike mammals, zebrafish SCI elicits transient immune activation and efficient debris clearance, without causing chronic inflammation.
View Article and Find Full Text PDFAm J Physiol Gastrointest Liver Physiol
January 2022
A single transcription factor, MIST1 (BHLHA15), maximizes secretory function in diverse secretory cells (like pancreatic acinar cells) by transcriptionally upregulating genes that elaborate secretory architecture. Here, we show that the scantly studied MIST1 target, ELAPOR1 (endosome/lysosome-associated apoptosis and autophagy regulator 1), is an evolutionarily conserved, novel mannose-6-phosphate receptor (M6PR) domain-containing protein. ELAPOR1 expression was specific to zymogenic cells (ZCs, the MIST1-expressing population in the stomach).
View Article and Find Full Text PDFDifferentiated cells can re-enter the cell cycle to repair tissue damage via a series of discrete morphological and molecular stages coordinated by the cellular energetics regulator mTORC1. We previously proposed the term "paligenosis" to describe this conserved cellular regeneration program. Here, we detail a molecular network regulating mTORC1 during paligenosis in both mouse pancreatic acinar and gastric chief cells.
View Article and Find Full Text PDFThe rapid rise of the CO level in the atmosphere has spurred the development of CO capture methods such as the use of biomimetic complexes that mimic carbonic anhydrase. In this study, model complexes with tris(2-pyridylmethyl)amine (TPA) were synthesized using various transition metals (Zn, Cu and Ni) to control the intrinsic proton-donating ability. The pK of the water coordinated to the metal, which indicates its proton-donating ability, was determined by potentiometric pH titration and found to increase in the order [(TPA)Cu(OH)] < [(TPA)Ni(OH)] < [(TPA)Zn(OH)].
View Article and Find Full Text PDFZinc complexes were synthesized as catalysts that mimic the ability of carbonic anhydrase (CA) for the CO hydration reaction (HO + CO → H + HCO). For these complexes, a tris(2-pyridylmethyl)amine (TPA) ligand mimicking only the active site, and a 6-((bis(pyridin-2-ylmethyl)amino)methyl)pyridin-2-ol (TPA-OH) ligand mimicking the hydrogen-bonding network of the secondary coordination sphere of CA were used. Potentiometric pH titration was used to determine the deprotonation ability of the Zn complexes, and their p values were found to be 8.
View Article and Find Full Text PDFTin oxide (SnO) nanowires are produced by the calcination of tin glycolate (SnCHO) nanowires, which are synthesized with tin oxalate (SnCO) and ethylene glycol the so-called polyol process. In this study, the growth mechanism of SnCHO nanowires was investigated by monitoring the synthesis using scanning and transmission electron microscopy. The length and diameter of the nanowires were 9.
View Article and Find Full Text PDFTo grow, insects must periodically shed their exoskeletons. This process, called ecdysis, is initiated by the endocrine release of Ecdysis Trigger Hormone (ETH) and has been extensively studied as a model for understanding the hormonal control of behavior. Understanding how ETH regulates ecdysis behavior, however, has been impeded by limited knowledge of the hormone's neuronal targets.
View Article and Find Full Text PDFThe endocrine system employs peptide hormone signals to translate environmental changes into physiological responses. The diffuse endocrine system embedded in the gastrointestinal barrier epithelium is one of the largest and most diverse endocrine tissues. Furthermore, it is the only endocrine tissue in direct physical contact with the microbial environment of the gut lumen.
View Article and Find Full Text PDFNeuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The dimmed (DIMM) basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMM's activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile.
View Article and Find Full Text PDFDifficulties in the extraction of membrane proteins from cell membrane and their solubilization in native conformations have hindered their structural and biochemical analysis. To overcome these difficulties, an amphipathic polypeptide was synthesized by the conjugation of octyl and glucosyl groups to the carboxyl groups of poly-γ-glutamic acid (PGA). This polymer, called amphipathic PGA (APG), self-assembles as mono-disperse oligomers consisted of 4-5 monomers.
View Article and Find Full Text PDFBioactive peptides are packaged in large dense-core secretory vesicles, which mediate regulated secretion by exocytosis. In a variety of tissues, the regulated release of neurotransmitters and hormones is dependent on calcium levels and controlled by vesicle-associated synaptotagmin (SYT) proteins. Drosophila express seven SYT isoforms, of which two (SYT-α and SYT-β) were previously found to be enriched in neuroendocrine cells.
View Article and Find Full Text PDFBioactive peptides are important therapeutic drugs, yet conventional methods of peptide synthesis are challenged to meet increasing demand. We developed a novel and efficient means of metabolic engineering: therapeutic peptide production in Drosophila and as a proof of concept, we demonstrate production of fully matured human insulin. This in vivo system offers an innovative means to produce valuable bioactive peptides for therapies, its inherent flexibility facilitates drug development, and its ease of producing fully processed peptides simplifies metabolic engineering of new peptide products.
View Article and Find Full Text PDFPurpose: Recently, two alternatively spliced survivin variants, survivin-ΔEx3 and survivin-2B, were identified in a single copy of the survivin gene. It has been reported that the expressions of survivin splice variants significantly correlates with the clinical results in many types of human carcinoma. We investigated the transcription levels of survivin and its splice variants in human colorectal carcinomas, and analyzed correlations between survivin expression levels and clinicopathologic features.
View Article and Find Full Text PDFBackground: In Drosophila, the basic-helix-loop-helix protein DIMM coordinates the molecular and cellular properties of all major neuroendocrine cells, irrespective of the secretory peptides they produce. When expressed by nonneuroendocrine neurons, DIMM confers the major properties of the regulated secretory pathway and converts such cells away from fast neurotransmission and toward a neuroendocrine state.
Results: We first identified 134 transcripts upregulated by DIMM in embryos and then evaluated them systematically using diverse assays (including embryo in situ hybridization, in vivo chromatin immunoprecipitation, and cell-based transactivation assays).
Background: The Drosophila basic helix-loop-helix (bHLH) gene dimmed (dimm) promotes a neurosecretory/neuroendocrine phenotype in cells but is not associated with specific neuropeptides or neurohormones. Rather, it is expressed by those peptidergic neurons that project long axons and appear to produce large amounts of secretory peptides. Here, we genetically transform nonpeptidergic neurons in Drosophila to study DIMM's action mechanisms.
View Article and Find Full Text PDFThis review considers evidence that defines a role for the transcription factor DIMMED in the regulation of insect neurosecretory cells. Genetic anatomical and molecular data all suggest DIMMED is a dedicated controller of the regulated secretory pathway. DIMM is normally expressed within diverse neuropeptide-expressing cells and appears highly correlated with a neurosecretory cell fate.
View Article and Find Full Text PDFThe bHLH transcription factor DIMMED has been associated with the differentiation of peptidergic cells in Drosophila. However, whether all Drosophila peptidergic cells express DIMM, and the extent to which all DIMM cells are peptidergic, have not been determined. To address these issues, we have mapped DIMM expression in the central nervous system (CNS) and periphery in the late larval stage Drosophila.
View Article and Find Full Text PDFThe basic helix-loop-helix (bHLH) protein DIMMED (DIMM) supports the differentiation of secretory properties in numerous peptidergic cells of Drosophila melanogaster. DIMM is coexpressed with diverse amidated neuropeptides and with the amidating enzyme peptidylglycine alpha-hydroxylating monooxygenase (PHM) in approximately 300 cells of the late embryo. Here we confirm that DIMM has transcription factor activity in transfected HEK 293 cells and that the PHM gene is a direct target.
View Article and Find Full Text PDFIn the Drosophila ventral nerve cord, a small number of neurons express the LIM-homeodomain gene apterous (ap). These ap neurons can be subdivided based upon axon pathfinding and their expression of neuropeptidergic markers. ap, the zinc finger gene squeeze, the bHLH gene dimmed, and the BMP pathway are all required for proper specification of these cells.
View Article and Find Full Text PDFNeuropeptide alpha-amidation is a common C-terminal modification of secretory peptides, frequently required for biological activity. In mammals, amidation is catalyzed by the sequential actions of two enzymes [peptidylglycine-alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL)] that are co-synthesized within a single bifunctional precursor. The Drosophila genome predicts expression of one monofunctional PHM gene and two monofunctional PAL genes.
View Article and Find Full Text PDFHere we describe a novel set of peptidergic neurons conserved throughout all developmental stages in the Drosophila central nervous system (CNS). We show that a small complement of 28 apterous-expressing cells (Ap-let neurons) in the ventral nerve cord (VNC) of Drosophila larvae co-express numerous gene products. The products include the neuroendocrine-specific bHLH regulator called Dimmed (Dimm), four neuropeptide biosynthetic enzymes (PC2, Fur1, PAL2, and PHM), and a specific dopamine receptor subtype (dDA1).
View Article and Find Full Text PDFProctolin is a bioactive neuropeptide that modulates interneuronal and neuromuscular synaptic transmission in a wide variety of arthropods. We present several lines of evidence to propose that the orphan G protein-coupled receptor CG6986 of Drosophila is a proctolin receptor. When expressed in mammalian cells, CG6986 confers second messenger activation after proctolin application, with an EC(50) of 0.
View Article and Find Full Text PDFNeuroendocrine cells are specialized to produce, maintain and release large stores of secretory peptides. We show that the Drosophila dimmed/Mist1 bHLH gene confers such a pro-secretory phenotype on neuroendocrine cells. dimmed is expressed selectively in central and peripheral neuroendocrine cells.
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