ERAdP facilitates package and biogenesis of dense core vesicles in Paneth cells to enhance intestinal antibacterial capacity
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE294515 | GEO | 2025/10/30
REPOSITORIES: GEO
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Project description:ERAdP facilitates package and biogenesis of dense core vesicles in Paneth cells to enhance intestinal antibacterial capacity
| PRJNA1250437 | ENA
Project description:The dense core vesicles (DCVs) of neuroendocrine cells are a rich source of bioactive molecules such as peptides, hormones, and neurotransmitters, but relatively little is known about how they are formed. Using fractionation profiling, a method that combines subcellular fractionation with mass spectrometry, we identified ∼1200 proteins in PC12 cell vesicle-enriched fractions, with DCV-associated proteins showing distinct profiles from proteins associated with other types of vesicles. To investigate the role of clathrin in DCV biogenesis, we stably transduced PC12 cells with an inducible short hairpin RNA targeting clathrin heavy chain, resulting in ∼85% protein loss. DCVs could still be observed in the cells by electron microscopy, but mature profiles were approximately fourfold less abundant than in mock-treated cells. By quantitative mass spectrometry, DCV-associated proteins were found to be reduced approximately twofold in clathrin-depleted cells as a whole and approximately fivefold in vesicle-enriched fractions. Our combined data sets enabled us to identify new candidate DCV components. Secretion assays revealed that clathrin depletion causes a near-complete block in secretagogue-induced exocytosis. Taken together, our data indicate that clathrin has a function in DCV biogenesis beyond its established role in removing unwanted proteins from the immature vesicle.
| S-EPMC5620375 | biostudies-literature
Project description:The intestine is the critical organ not only for processing and resorbing nutrients from ingested food but also for defending the organism from external stresses such as pathogens. These functions are mainly carried out by the epithelium which is constantly being self-renewed throughout adult life. Intestinal epithelial homeostasis is maintained through well-controlled cell proliferation of the stem cells and transient amplifying cells and the apoptotic degeneration of epithelial cells, mostly at or near the tip of the villi. Many genes and pathways have been found to influence intestinal epithelial cell proliferation. Among them is the mTORC1 signaling pathway, whose activation is known to increase cell proliferation. Here, we report the first intestinal epithelial specific knockout (IEC-KO) of an amino acid transporter capable of activating mTORC1. We show that the transporter, slc7a5, is highly expressed in the intestinal crypt and slc7a5 IEC-KO leads to expected reduction in mTORC1 signal in the crypt or even in intestinal organoids in vitro. Surprisingly, slc7a5 IEC-KO leads to increased proliferation of both transit amplifying cells and crypt base stem cells but a reduction in the secretory cells, particularly mature Paneth cells in the crypt base. Our scRNA-seq and electron microscopic analyses reveals that slc7a5 IEC-KO causes dedifferentiation of the Paneth cells, leading to drastically reduced secretory granules and lysozyme expression without affecting the overall Paneth cell number. We further show that slc7a5 IEC-KO mice are prone to induced colitis due to this loss of Paneth cell differentiation. We propose a model where slc7a5 regulates secretory cell differentiation to affect stem cell niche and/or inflammatory response to regulate cell proliferation in the crypts.
2024-04-24 | GSE216930 | GEO
Project description:The SNARE protein vti1a is proposed to drive fusion of intracellular organelles, but recent data also implicated vti1a in exocytosis. Here we show that vti1a is absent from mature secretory vesicles in adrenal chromaffin cells, but localizes to a compartment near the trans-Golgi network, partially overlapping with syntaxin-6. Exocytosis is impaired in vti1a null cells, partly due to fewer Ca(2+)-channels at the plasma membrane, partly due to fewer vesicles of reduced size and synaptobrevin-2 content. In contrast, release kinetics and Ca(2+)-sensitivity remain unchanged, indicating that the final fusion reaction leading to transmitter release is unperturbed. Additional deletion of the closest related SNARE, vti1b, does not exacerbate the vti1a phenotype, and vti1b null cells show no secretion defects, indicating that vti1b does not participate in exocytosis. Long-term re-expression of vti1a (days) was necessary for restoration of secretory capacity, whereas strong short-term expression (hours) was ineffective, consistent with vti1a involvement in an upstream step related to vesicle generation, rather than in fusion. We conclude that vti1a functions in vesicle generation and Ca(2+)-channel trafficking, but is dispensable for transmitter release.
| S-EPMC4194101 | biostudies-literature
Project description:HPS1, a BLOC-3 subunit that acts as a guanine nucleotide exchange factor of Rab32/38, may play a role in the removal of VAMP7 during the maturation of large dense core vesicles of Paneth cells. Loss of HPS1 impairs lysozyme secretion and alters the composition of intestinal microbiota, which may explain the susceptibility of HPS-associated inflammatory bowel disease. Hermansky-Pudlak syndrome (HPS) is characterized by oculocutaneous albinism, bleeding tendency, and other chronic organ lesions due to defects in tissue-specific lysosome-related organelles (LROs). For some HPS subtypes, such as HPS-1, it is common to have symptoms of HPS-associated inflammatory bowel disease (IBD). However, its underlying mechanism is largely unknown. HPS1 is a subunit of the BLOC-3 complex which functions in the biogenesis of LROs. Large dense core vesicles (LDCVs) in Paneth cells of the intestine are a type of LROs. We here first report the abnormal LDCV morphology (increased number and enlarged size) in HPS1-deficient pale ear (ep) mice. Similar to its role in melanosome maturation, HPS1 plays an important function in the removal of VAMP7 from LDCVs to promote the maturation of LDCVs. The immature LDCVs in ep mice are defective in regulated secretion of lysozyme, a key anti-microbial peptide in the intestine. We observed changes in the composition of intestinal microbiota in both HPS-1 patients and ep mice. These findings provide insights into the underlying mechanism of HPS-associated IBD development, which may be implicated in possible therapeutic intervention of this devastating condition.
| S-EPMC7674556 | biostudies-literature
Project description:Processes underlying the formation of dense core secretory granules (DCGs) of neuroendocrine cells are poorly understood. Here, we present evidence that DCG biogenesis is dependent on the secretory protein secretogranin (Sg) II, a member of the granin family of pro-hormone cargo of DCGs in neuroendocrine cells. Depletion of SgII expression in PC12 cells leads to a decrease in both the number and size of DCGs and impairs DCG trafficking of other regulated hormones. Expression of SgII fusion proteins in a secretory-deficient PC12 variant rescues a regulated secretory pathway. SgII-containing dense core vesicles share morphological and physical properties with bona fide DCGs, are competent for regulated exocytosis, and maintain an acidic luminal pH through the V-type H(+)-translocating ATPase. The granulogenic activity of SgII requires a pH gradient along this secretory pathway. We conclude that SgII is a critical factor for the regulation of DCG biogenesis in neuroendocrine cells, mediating the formation of functional DCGs via its pH-dependent aggregation at the trans-Golgi network.
| S-EPMC2843166 | biostudies-literature
Project description:Chromogranin A and B (Cgs) are considered to be master regulators of cargo sorting for the regulated secretory pathway (RSP) and dense-core vesicle (DCV) biogenesis. To test this, we analyzed the release of neuropeptide Y (NPY)-pHluorin, a live RSP reporter, and the distribution, number, and appearance of DCVs, in mouse hippocampal neurons lacking expression of CHGA and CHGB genes. qRT-PCR analysis showed that expression of other granin family members was not significantly altered in CgA/B-/- neurons. As synaptic maturation of developing neurons depends on secretion of trophic factors in the RSP, we first analyzed neuronal development in standardized neuronal cultures. Surprisingly, dendritic and axonal length, arborization, synapse density, and synaptic vesicle accumulation in synapses were all normal in CgA/B-/- neurons. Moreover, the number of DCVs outside the soma, stained with endogenous marker Secretogranin II, the number of NPY-pHluorin puncta, and the total amount of reporter in secretory compartments, as indicated by pH-sensitive NPY-pHluorin fluorescence, were all normal in CgA/B-/- neurons. Electron microscopy revealed that synapses contained a normal number of DCVs, with a normal diameter, in CgA/B-/- neurons. In contrast, CgA/B-/- chromaffin cells contained fewer and smaller secretory vesicles with a smaller core size, as previously reported. Finally, live-cell imaging at single vesicle resolution revealed a normal number of fusion events upon bursts of action potentials in CgA/B-/- neurons. These events had normal kinetics and onset relative to the start of stimulation. Taken together, these data indicate that the two chromogranins are dispensable for cargo sorting in the RSP and DCV biogenesis in mouse hippocampal neurons.
| S-EPMC5814729 | biostudies-literature
Project description:Large dense core vesicles (LDCVs) mediate the regulated release of neuropeptides and peptide hormones. HID-1 is a trans-Golgi network (TGN) localized peripheral membrane protein contributing to LDCV formation. There is no information about HID-1 structure or domain architecture, and thus it remains unknown how HID-1 binds to the TGN and performs its function. We report that the N-terminus of HID-1 mediates membrane binding through a myristoyl group with a polybasic amino acid patch but lacks specificity for the TGN. In addition, we show that the C-terminus serves as the functional domain. Indeed, this isolated domain, when tethered to the TGN, can rescue the neuroendocrine secretion and sorting defects observed in HID-1 KO cells. Finally, we report that a point mutation within that domain, identified in patients with endocrine and neurological deficits, leads to loss of function.
| S-EPMC10522040 | biostudies-literature
Project description:Paneth cells are antimicrobial peptide-secreting cells located at the base of the crypts of the small intestine. The proteome of Paneth cells is not well defined because of their co-existence with stem cells making it difficult to culture Panth cells alone in vitro. Using a simplied toluidine blue O method for staining mouse intestinal tissue, laser capture microdissection (LCM) to isolate cells from the crypt region and surfactant assisted one pot protein digestion, we identified more than 1,300 proteins from crypts equivalent to 18,000 cells. Compared with the proteomes of villi and smooth muscle regions, the crypt proteome is highly enriched in defensins, lysozymes and other antimicrobial peptides that are characteristic of Paneth cells. The sensitivity of the LCM-based proteomics approach was also assessed using a smaller number of cell equivalent tissues, a comparable proteomic coverage can be achieved with 3,600 cells. This work is the first proteomics study of intestinal tissue enriched with Paneth cells. The simplied workflow enables profiling of Paneth cell associated pathological changes at the proteome level directly from frozen intestinal tissue. It may also be useful for proteomics studies of other spatially resolved cell types from other tissues.
2022-10-12 | PXD034143 | Pride
Project description:Gene inactivation of the orphan G protein-coupled receptor Lgr4, a paralog of the epithelial stem cell marker Lgr5, results in 50% decrease of epithelial cell proliferation and 80% reduction in terminal differentiation of Paneth cells in postnatal mouse intestinal crypts. When cultured ex vivo, Lgr4-deficient crypts or progenitors, but not Lgr5-deficient progenitors, die rapidly with dramatic downregulation of stem cell markers and Wnt target genes, including Lgr5. Partial rescue of this phenotype is achieved by LiCl addition to the culture medium, but not by Wnt agonists. Our results identify Lgr4 as a permissive factor of the Wnt pathway in the intestine and, as such, as a potential target for intestinal cancer therapy. Microarray hybridization was performed on LGR4 KO intestinal crypts at day 0, day 0.5 and day 1 versus wild-type crypts. The effects of LiCl treatment on LGR4 KO crypts at day1 versus control cells were investigated. After amplification and labelling, sample pairs were hybridized onto Mouse Exonic Evidence Based Oligonucleotide (MEEBO) arrays containing on average 38784 mouse 70mer oligonucleotide probes (Stanford University, US). Hybridizations were replicated with dye swap.
2012-03-10 | E-GEOD-27904 | biostudies-arrayexpress