Cdc42 controls secretory granules morphology in rodent salivary glands in vivo.
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ABSTRACT:
SUBMITTER: Shitara A
PROVIDER: S-EPMC7039664 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Summary Salivary gland cells, which secrete water in response to neuronal stimulation, are closely connected to other neurons. Transcriptomic studies show that salivary glands also express some proteins responsible for neuronal function. However, the physiological functions of these common neuro-exocrine factors in salivary glands are largely unknown. Here, we studied the function of Neuronal growth regulator 1 (NEGR1) in the salivary gland cells. NEGR1 was also expressed in mouse and human salivary glands. The structure of salivary glands of Negr1 knockout (KO) mice was normal. Negr1 KO mice showed tempered carbachol- or thapsigargin-induced intracellular Ca2+ increases and store-operated Ca2+ entry. Of interest, the activity of the large-conductance Ca2+-activated K+ channel (BK channel) was increased, whereas Ca2+-activated Cl− channel ANO1 channel activity was not altered in Negr1 KO mice. Pilocarpine- and carbachol-induced salivation was decreased in Negr1 KO mice. These results suggest that NEGR1 influence salivary secretion though the muscarinic Ca2+ signaling. Graphical abstract Highlights • Negr1 knockout mice show reduced salivation• NEGR1 is essential for muscarinic Ca2+ signaling in the submandibular gland• The study provides an explanation for dry mouth among depression patients Biological sciences; Molecular biology; Molecular neuroscience; Neuroscience
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Project description:Salivary glands exert exocrine secretory function to provide saliva for lubrication and protection of the oral cavity. Its epithelium consists of several differentiated cell types, including acinar, ductal and myoepithelial cells, that are maintained in a lineage-restricted manner during homeostasis or after mild injuries. Glandular regeneration following a near complete loss of secretory cells, however, may involve cellular plasticity, although the mechanism and extent of such plasticity remain unclear. Here, by combining lineage-tracing experiments with a model of severe glandular injury in the mouse submandibular gland, we show that de novo formation of acini involves induction of cellular plasticity in multiple non-acinar cell populations. Fate-mapping analysis revealed that, although ductal stem cells marked by cytokeratin K14 and Axin2 undergo a multipotency switch, they do not make a significant contribution to acinar regeneration. Intriguingly, more than 80% of regenerated acini derive from differentiated cells, including myoepithelial and ductal cells, that appear to dedifferentiate to a progenitor-like state before re-differentiation into acinar cells. The potential of diverse cell populations serving as a reserve source for acini widens the therapeutic options for hyposalivation.
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Project description:Radiation treatment of head and neck cancers causes irreversible damage of the salivary glands (SG). Here, we introduce a preclinical mouse model for small-interfering RNA (siRNA)-based gene silencing to provide protection of SG from radiation-induced apoptosis. Novel, pH-responsive nanoparticles complexed with siRNAs were introduced into mouse submandibular glands (SMG) by retroductal injection to modulate gene expression in vivo. To validate this approach, we first targeted Nkcc1, an ion transporter that is essential for saliva secretion. Nkcc1 siRNA delivery resulted in efficient knockdown, as quantified at the mRNA and the protein levels, and the functional result of Nkcc1 knockdown phenocopied the severe decrease in saliva secretion, characteristic of the systemic Nkcc1 gene knockout. To establish a strategy to prevent apoptotic cell loss due to radiation damage, siRNAs targeting the proapoptotic Pkc? gene were administered into SMG before ionizing radiation. Knockdown of Pkc? not only reduced the number of apoptotic cells during the acute phase of radiation damage, but also markedly improved saliva secretion at 3 months in irradiated animals, indicating that this treatment confers protection from hyposalivation. These results demonstrate that nanoparticle delivery of siRNAs targeting a proapoptotic gene is a localized, nonviral, and effective means of conferring radioprotection to the SGs.
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Project description:Cell division cycle 42 (Cdc42) is a member of the Rho GTPase family and has pivotal functions in actin organization, cell migration and proliferation. Cdc42 has been shown to regulate antigen (Ag)-uptake in immature dendritic cells (DC) and controls their migration from tissues to lymph nodes. Previous reports demonstrated that Cdc42 is inactivated upon DC-maturation to avoid continued Ag-acquisition. To further study the molecular mechanisms of DC-control by Cdc42, we used bone marrow-derived DCs from Cdc42-deficient mice. We show that Cdc42-deficient DCs are phenotypically mature without additional maturation stimuli, as they upregulate CD86 from intracellular storages to the cell surface. They also accumulate invariant chain (Ii)-MHC class II complexes at the cell surface, which cannot efficiently present peptide Ag for priming of Ag-specific CD4 T cells. Lack of Cdc42 in immature DCs does not allow MHC class II maturation, as lysosomal Cathepsins are lost into the supernatant and Ii-MHC class II complexes cannot mature. Therefore Cdc42-deficient DCs are "pseudomature" and lose most functional hallmarks of antigen-presenting cells. Our results propose that Cdc42 keeps DCs in an immature state, while downregulation of Cdc42-activity during maturation facilitates generation of CD86+MHCII+ mature DCs.
2015-10-12 | PXD001934 | Pride
Project description:BackgroundSecretory carcinoma is a more recently described subtype of salivary gland carcinoma that may pose diagnostic challenges and frequently harbors NTRK fusions that may successfully be targeted by TRK inhibitors in advanced disease.CaseWe present the case of a female patient with secretory carcinoma arising in the base of tongue with persistent disease after debulking surgery and definitive chemoradiation. As an alternative to salvage surgery, which would have resulted in significant impairment of swallowing and speech function, a targeted therapy with the TRK-inhibitor larotrectinib against an identified ETV6-NTRK3 fusion product was initiated. Larotrectinib treatment has been well tolerated, resulted in durable complete response and the patient maintains good swallowing and speech function.ConclusionThe presented case underscores the importance of the accurate diagnosis of secretory carcinoma. It further highlights the impact of molecular testing as targeted therapies may play an important role in the management of advanced salivary gland cancers.
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