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Cancer-associated fibroblasts (CAFs) and nerves, components of the tumor microenvironment, have each been shown to directly promote gastrointestinal cancers. However, it remains unknown whether these cells interact with each other to regulate cancer progression. We found that in colorectal cancer (CRC) norepinephrine induces ADRB2-dependent nerve growth factor (NGF) secretion from CAFs, which in turn increases intra-tumor sympathetic innervation and norepinephrine accumulation. Adrenergic stimulation accelerates CRC growth through ADRA2A/Gi-mediated activation of Yes-Associated Protein (YAP). NGF from CAFs directly enhances CRC cell growth via the PI3K/AKT pathway. Treatment with a tropomyosin receptor kinase (Trk) inhibitor decreased YAP and AKT activation and CRC progression in mice. In human CRC, high NGF expression is associated with the mesenchymal-like tumor subtype and poor patient survival. These findings suggest a central role for reciprocal CAF-nerve crosstalk in promoting CRC progression. Blocking this feedforward loop with a Trk inhibitor may represent a potential therapeutic approach for CRC.
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In the prevailing model, Lgr5+ cells are the only intestinal stem cells (ISCs) that sustain homeostatic epithelial regeneration by upward migration of progeny through elusive upper crypt transit-amplifying (TA) intermediates. Here, we identify a proliferative upper crypt population marked by Fgfbp1, in the location of putative TA cells, that is transcriptionally distinct from Lgr5+ cells. Using a kinetic reporter for time-resolved fate mapping and Fgfbp1-CreERT2 lineage tracing, we establish that Fgfbp1+ cells are multi-potent and give rise to Lgr5+ cells, consistent with their ISC function. Fgfbp1+ cells also sustain epithelial regeneration following Lgr5+ cell depletion. We demonstrate that FGFBP1, produced by the upper crypt cells, is an essential factor for crypt proliferation and epithelial homeostasis. Our findings support a model in which tissue regeneration originates from upper crypt Fgfbp1+ cells that generate progeny propagating bi-directionally along the crypt-villus axis and serve as a source of Lgr5+ cells in the crypt base.
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Mucosa Intestinal , Receptores Acoplados a Proteínas G , Receptores Acoplados a Proteínas G/metabolismo , Animales , Ratones , Mucosa Intestinal/metabolismo , Mucosa Intestinal/citología , Células Madre/metabolismo , Células Madre/citología , Linaje de la Célula , Regeneración , Proliferación Celular , Células Epiteliales/metabolismo , Células Epiteliales/citología , Ratones Endogámicos C57BL , HomeostasisRESUMEN
The currently accepted intestinal epithelial cell organization model proposes that Lgr5+ crypt-base columnar (CBC) cells represent the sole intestinal stem cell (ISC) compartment. However, previous studies have indicated that Lgr5+ cells are dispensable for intestinal regeneration, leading to two major hypotheses: one favoring the presence of a quiescent reserve ISC and the other calling for differentiated cell plasticity. To investigate these possibilities, we studied crypt epithelial cells in an unbiased fashion via high-resolution single-cell profiling. These studies, combined with in vivo lineage tracing, show that Lgr5 is not a specific ISC marker and that stemness potential exists beyond the crypt base and resides in the isthmus region, where undifferentiated cells participate in intestinal homeostasis and regeneration following irradiation (IR) injury. Our results provide an alternative model of intestinal epithelial cell organization, suggesting that stemness potential is not restricted to CBC cells, and neither de-differentiation nor reserve ISC are drivers of intestinal regeneration.
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Homeostasis , Mucosa Intestinal , Receptores Acoplados a Proteínas G , Regeneración , Células Madre , Animales , Células Madre/metabolismo , Células Madre/citología , Ratones , Mucosa Intestinal/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Intestinos/citología , Diferenciación Celular , Ratones Endogámicos C57BL , Células Epiteliales/metabolismo , Análisis de la Célula Individual , MasculinoRESUMEN
Cancer cells have been shown to exploit neurons to modulate their survival and growth, including through establishment of neural circuits within the central nervous system (CNS) 1-3 . Here, we report a distinct pattern of cancer-nerve interactions between the peripheral nervous system (PNS) and gastric cancer (GC). In multiple GC mouse models, nociceptive nerves demonstrated the greatest degree of nerve expansion in an NGF-dependent manner. Neural tracing identified CGRP+ peptidergic neurons as the primary gastric sensory neurons. Three-dimensional co-culture models showed that sensory neurons directly connect with gastric cancer spheroids through synapse-like structures. Chemogenetic activation of sensory neurons induced the release of calcium into the cytoplasm of cancer cells, promoting tumor growth and metastasis. Pharmacological ablation of sensory neurons or treatment with CGRP inhibitors suppressed tumor growth and extended survival. Depolarization of gastric tumor membranes through in vivo optogenetic activation led to enhanced calcium flux in nodose ganglia and CGRP release, defining a cancer cell-peptidergic neuronal circuit. Together, these findings establish the functional connectivity between cancer and sensory neurons, identifying this pathway as a potential therapeutic target.
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BACKGROUND & AIMS: The intestinal epithelium functions both in nutrient absorption and as a barrier, separating the luminal contents from a network of vascular, fibroblastic, and immune cells underneath. After injury to the intestine, multiple cell populations cooperate to drive regeneration of the mucosal barrier, including lymphatic endothelial cells (LECs). A population of granulocytic immature myeloid cells (IMCs), marked by Hdc, participate in regeneration of multiple organs such as the colon and central nervous system, and their contribution to intestinal regeneration was investigated. METHODS: By using male and female histidine decarboxylase (Hdc) green fluorescent reporter (GFP) mice, we investigated the role of Hdc+ IMCs in intestinal regeneration after exposure to 12 Gy whole-body irradiation. The movement of IMCs was analyzed using flow cytometry and immunostaining. Ablation of Hdc+ cells using the HdcCreERT2 tamoxifen-inducible recombinase Cre system, conditional knockout of Prostaglandin-endoperoxidase synthase 2 (Ptgs2) in Hdc+ cells using HdcCre; Ptgs2 floxed mice, and visualization of LECs using Prox1tdTomato mice also was performed. The role of microbial signals was investigated by knocking down mice gut microbiomes using antibiotic cocktail gavages. RESULTS: We found that Hdc+ IMCs infiltrate the injured intestine after irradiation injury and promote epithelial regeneration in part by modulating LEC activity. Hdc+ IMCs express Ptgs2 (encoding cyclooxygenase-2/COX-2), and enables them to produce prostaglandin E2. Prostaglandin E2 acts on the prostaglandin E2 receptor 4 receptor (EP4) on LECs to promote lymphangiogenesis and induce the expression of proregenerative factors including R-spondin 3. Depletion of gut microbes leads to reduced intestinal regeneration by impaired recruitment of IMCs. CONCLUSIONS: Altogether, our results unveil a critical role for IMCs in intestinal repair by modulating LEC activity and implicate gut microbes as mediators of intestinal regeneration.
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Células Endoteliales , Intestinos , Células Mieloides , Proteína Fluorescente Roja , Regeneración , Animales , Femenino , Masculino , Ratones , Ciclooxigenasa 2 , ProstaglandinasRESUMEN
PDGFRA-expressing mesenchyme supports intestinal stem cells. Stomach epithelia have related niche dependencies, but their enabling mesenchymal cell populations are unknown, in part because previous studies pooled the gastric antrum and corpus. Our high-resolution imaging, transcriptional profiling, and organoid assays identify regional subpopulations and supportive capacities of purified mouse corpus and antral PDGFRA+ cells. Sub-epithelial PDGFRAHi myofibroblasts are principal sources of BMP ligands and two molecularly distinct pools distribute asymmetrically along antral glands but together fail to support epithelial growth in vitro. In contrast, PDGFRALo CD55+ cells strategically positioned beneath gastric glands promote epithelial expansion in the absence of other cells or factors. This population encompasses a small fraction expressing the BMP antagonist Grem1. Although Grem1+ cell ablation in vivo impairs intestinal stem cells, gastric stem cells are spared, implying that CD55+ cell activity in epithelial self-renewal derives from other subpopulations. Our findings shed light on spatial, molecular, and functional organization of gastric mesenchyme and the spectrum of signaling sources for epithelial support.
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Mucosa Gástrica , Estómago , Ratones , Animales , Células Madre , Intestinos , Antro Pilórico , Proteínas Tirosina Quinasas Receptoras , Células EpitelialesRESUMEN
Despite standardized surgical technique and peri-operative care, metabolic outcomes of bariatric surgery are not uniform. Adaptive changes in brain function may play a crucial role in achieving optimal postbariatric weight loss. This review follows the anatomic-physiologic structure of the postbariatric nutrient-gut-brain communication chain through its key stations and provides a concise summary of recent findings in bariatric physiology, with a special focus on the composition of the intestinal milieu, intestinal nutrient sensing, vagal nerve-mediated gastrointestinal satiation signals, circulating hormones and nutrients, as well as descending neural signals from the forebrain. The results of interventional studies using brain or vagal nerve stimulation to induce weight loss are also summarized. Ultimately, suggestions are made for future diagnostic and therapeutic research for the treatment of obesity.
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Cirugía Bariátrica , Derivación Gástrica , Obesidad Mórbida , Humanos , Cirugía Bariátrica/métodos , Encéfalo , Gastrectomía/métodos , Derivación Gástrica/métodos , Obesidad/cirugía , Obesidad Mórbida/cirugía , Pérdida de Peso/fisiología , Comunicación CelularRESUMEN
Signals from the surrounding niche drive proliferation and suppress differentiation of intestinal stem cells (ISCs) at the bottom of intestinal crypts. Among sub-epithelial support cells, deep sub-cryptal CD81+ PDGFRAlo trophocytes capably sustain ISC functions ex vivo. Here, we show that mRNA and chromatin profiles of abundant CD81- PDGFRAlo mouse stromal cells resemble those of trophocytes and that both populations provide crucial canonical Wnt ligands. Mesenchymal expression of key ISC-supportive factors extends along a spatial and molecular continuum from trophocytes into peri-cryptal CD81- CD55hi cells, which mimic trophocyte activity in organoid co-cultures. Graded expression of essential niche factors is not cell-autonomous but dictated by the distance from bone morphogenetic protein (BMP)-secreting PDGFRAhi myofibroblast aggregates. BMP signaling inhibits ISC-trophic genes in PDGFRAlo cells near high crypt tiers; that suppression is relieved in stromal cells near and below the crypt base, including trophocytes. Cell distances thus underlie a self-organized and polar ISC niche.
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Mucosa Intestinal , Nicho de Células Madre , Animales , Ratones , Mucosa Intestinal/metabolismo , Intestinos , Transducción de Señal , Diferenciación Celular , Proliferación CelularRESUMEN
The intestinal epithelium functions both in nutrient absorption and as a barrier, separating the luminal contents from a network of vascular, fibroblastic, and immune cells underneath. Following injury to the intestine, multiple different cell populations cooperate to drive regeneration of the mucosa. Immature myeloid cells (IMCs), marked by histidine decarboxylase ( Hdc ), participate in regeneration of multiple organs such as the colon and central nervous system. Here, we found that IMCs infiltrate the injured intestine and promote epithelial regeneration and modulate LEC activity. IMCs produce prostaglandin E2 (PGE2), which promotes LEC lymphangiogenesis and upregulation of pro-regenerative factors including RSPO3. Moreover, we found that IMC recruitment into the intestine is driven by invading microbial signals. Accordingly, antibiotic eradication of the intestinal microbiome prior to WB-IR inhibits IMC recruitment, and consequently, intestinal recovery. We propose that IMCs play a critical role in intestinal repair and implicate gut microbes as mediators of intestinal regeneration.
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R-spondins are critical regulators of gastric epithelial cells, with Lgr5 receptor historically considered as their main signaling transducer. Recent work by Wizenty et al (2022) now revealed distinct roles for Lgr4 and Lgr5 in directing gland reconstitution following H. pylori infection, shedding new light on the complexities of Rspo signaling during gastric regeneration and raising questions about antral stem cell hierarchy.
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Receptores Acoplados a Proteínas G , Trombospondinas , Transducción de Señal , Células Madre , Estómago , Trombospondinas/genética , Vía de Señalización WntRESUMEN
Intestinal ganglionic cells in the adult enteric nervous system (ENS) are continually exposed to stimuli from the surrounding microenvironment and need at times to respond to disturbed homeostasis following acute intestinal injury. The kinase DCLK1 and intestinal Dclk1-positive cells have been reported to contribute to intestinal regeneration. Although Dclk1-positive cells are present in adult enteric ganglia, their cellular identity and response to acute injury have not been investigated in detail. Here, we reveal the presence of distinct Dclk1-tdTom+/CD49b+ glial-like and Dclk1-tdTom+/CD49b- neuronal cell types in adult myenteric ganglia. These ganglionic cells demonstrate distinct patterns of tracing over time yet show a similar expansion in response to elevated serotonergic signaling. Interestingly, Dclk1-tdTom+ glial-like and neuronal cell types appear resistant to acute irradiation injury-mediated cell death. Moreover, Dclk1-tdTom+/CD49b+ glial-like cells show prominent changes in gene expression profiles induced by injury, in contrast to Dclk1-tdTom+/CD49b- neuronal cell types. Finally, subsets of Dclk1-tdTom+/CD49b+ glial-like cells demonstrate prominent overlap with Nestin and p75NTR and strong responses to elevated serotonergic signaling or acute injury. These findings, together with their role in early development and their neural crest-like gene expression signature, suggest the presence of reserve progenitor cells in the adult Dclk1 glial cell lineage.NEW & NOTEWORTHY The kinase DCLK1 identifies glial-like and neuronal cell types in adult murine enteric ganglia, which resist acute injury-mediated cell death yet differ in their cellular response to injury. Interestingly, Dclk1-labeled glial-like cells show prominent transcriptional changes in response to injury and harbor features reminiscent of previously described enteric neural precursor cells. Our data thus add to recently emerging evidence of reserve cellular plasticity in the adult enteric nervous system.
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Sistema Nervioso Entérico , Células-Madre Neurales , Animales , Sistema Nervioso Entérico/fisiología , Integrina alfa2/metabolismo , Ratones , Ratones Transgénicos , Neuroglía/metabolismo , Neuronas/metabolismoRESUMEN
BACKGROUND AND AIMS: The gastric epithelium undergoes continuous turnover. Corpus epithelial stem cells located in the gastric isthmus serve as a source of tissue self-renewal. We recently identified the transcription factor Mist1 as a marker for this corpus stem cell population that can give rise to cancer. The aim here was to investigate the regulation of the Mist1+ stem cells in the response to gastric injury and inflammation. METHODS: We used Mist1CreERT;R26-Tdtomato mice in two models of injury and inflammation: the acetic acid-induced ulcer and infection with Helicobacter felis. We analysed lineage tracing at both early (7 to 30 days) and late (30 to 90 days) time points. Mist1CreERT;R26-Tdtomato;Lgr5DTR-eGFP mice were used to ablate the corpus basal Lgr5+ cell population. Constitutional and conditional Wnt5a knockout mice were used to investigate the role of Wnt5a in wound repair and lineage tracing from the Mist1+ stem cells. RESULTS: In both models of gastric injury, Mist1+ isthmus stem cells more rapidly proliferate and trace entire gastric glands compared with the normal state. In regenerating tissue, the number of traced gastric chief cells was significantly reduced, and ablation of Lgr5+ chief cells did not affect Mist1-derived lineage tracing and tissue regeneration. Genetic deletion of Wnt5a impaired proliferation in the gastric isthmus and lineage tracing from Mist1+ stem cells. Similarly, depletion of innate lymphoid cells, the main source of Wnt5a, also resulted in reduced proliferation and Mist1+ isthmus cell tracing. CONCLUSION: Gastric Mist1+ isthmus cells are the main supplier of regenerated glands and are activated in part through Wnt5a pathway.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Células Principales Gástricas/metabolismo , Células Epiteliales/metabolismo , Mucosa Gástrica/metabolismo , Células Madre/metabolismo , Vía de Señalización Wnt , Animales , Proliferación Celular , Inflamación/metabolismo , Ratones , Ratones Noqueados , Úlcera Gástrica/metabolismo , Cicatrización de HeridasRESUMEN
BACKGROUND & AIMS: Histidine decarboxylase (HDC), the histamine-synthesizing enzyme, is expressed in a subset of myeloid cells but also marks quiescent myeloid-biased hematopoietic stem cells (MB-HSCs) that are activated upon myeloid demand injury. However, the role of MB-HSCs in dextran sulfate sodium (DSS)-induced acute colitis has not been addressed. METHODS: We investigated HDC+ MB-HSCs and myeloid cells by flow cytometry in acute intestinal inflammation by treating HDC-green fluorescent protein (GFP) male mice with 5% DSS at various time points. HDC+ myeloid cells in the colon also were analyzed by flow cytometry and immunofluorescence staining. Knockout of the HDC gene by using HDC-/-; HDC-GFP and ablation of HDC+ myeloid cells by using HDC-GFP; HDC-tamoxifen-inducible recombinase Cre system; diphtheria toxin receptor (DTR) mice was performed. The role of H2-receptor signaling in acute colitis was addressed by treatment of DSS-treated mice with the H2 agonist dimaprit dihydrochloride. Kaplan-Meier survival analysis was performed to assess the effect on survival. RESULTS: In acute colitis, rapid activation and expansion of MB-HSC from bone marrow was evident early on, followed by a gradual depletion, resulting in profound HSC exhaustion, accompanied by infiltration of the colon by increased HDC+ myeloid cells. Knockout of the HDC gene and ablation of HDC+ myeloid cells enhance the early depletion of HDC+ MB-HSC, and treatment with H2-receptor agonist ameliorates the depletion of MB-HSCs and resulted in significantly increased survival of HDC-GFP mice with acute colitis. CONCLUSIONS: Exhaustion of bone marrow MB-HSCs contributes to the progression of DSS-induced acute colitis, and preservation of quiescence of MB-HSCs by the H2-receptor agonist significantly enhances survival, suggesting the potential for therapeutic utility.
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Médula Ósea/patología , Colitis/patología , Células Madre Hematopoyéticas/patología , Histamina/metabolismo , Histidina Descarboxilasa/fisiología , Inflamación/patología , Intestinos/patología , Células Mieloides/patología , Animales , Médula Ósea/inmunología , Médula Ósea/metabolismo , Colitis/etiología , Colitis/metabolismo , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/metabolismo , Inflamación/etiología , Inflamación/metabolismo , Intestinos/inmunología , Intestinos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células Mieloides/inmunología , Células Mieloides/metabolismo , Transducción de SeñalRESUMEN
AIMS/HYPOTHESIS: Compared with the general population, individuals with diabetes have a higher risk of developing severe acute pancreatitis, a highly debilitating and potentially lethal inflammation of the exocrine pancreas. In this study, we investigated whether 1-deoxysphingolipids, atypical lipids that increase in the circulation following the development of diabetes, exacerbate the severity of pancreatitis in a diabetic setting. METHODS: We analysed whether administration of an L-serine-enriched diet to mouse models of diabetes, an established method for decreasing the synthesis of 1-deoxysphingolipids in vivo, reduced the severity of acute pancreatitis. Furthermore, we elucidated the molecular mechanisms underlying the lipotoxicity exerted by 1-deoxysphingolipids towards rodent pancreatic acinar cells in vitro. RESULTS: We demonstrated that L-serine supplementation reduced the damage of acinar tissue resulting from the induction of pancreatitis in diabetic mice (average histological damage score: 1.5 in L-serine-treated mice vs 2.7 in the control group). At the cellular level, we showed that L-serine decreased the production of reactive oxygen species, endoplasmic reticulum stress and cellular apoptosis in acinar tissue. Importantly, these parameters, together with DNA damage, were triggered in acinar cells upon treatment with 1-deoxysphingolipids in vitro, suggesting that these lipids are cytotoxic towards pancreatic acinar cells in a cell-autonomous manner. In search of the initiating events of the observed cytotoxicity, we discovered that 1-deoxysphingolipids induced early mitochondrial dysfunction in acinar cells, characterised by ultrastructural alterations, impaired oxygen consumption rate and reduced ATP synthesis. CONCLUSIONS/INTERPRETATION: Our results suggest that 1-deoxysphingolipids directly damage the functionality of pancreatic acinar cells and highlight that an L-serine-enriched diet may be used as a promising prophylactic intervention to reduce the severity of pancreatitis in the context of diabetes.
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Células Acinares/efectos de los fármacos , Diabetes Mellitus Experimental/metabolismo , Páncreas/efectos de los fármacos , Pancreatitis/metabolismo , Serina/farmacología , Células Acinares/metabolismo , Células Acinares/ultraestructura , Animales , Apoptosis/efectos de los fármacos , Ceruletida/toxicidad , Daño del ADN/efectos de los fármacos , Diabetes Mellitus Experimental/complicaciones , Modelos Animales de Enfermedad , Estrés del Retículo Endoplásmico/efectos de los fármacos , Técnicas In Vitro , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Consumo de Oxígeno/efectos de los fármacos , Páncreas/citología , Pancreatitis/etiología , Especies Reactivas de Oxígeno/metabolismo , Índice de Severidad de la Enfermedad , Esfingolípidos/metabolismo , Esfingolípidos/farmacologíaRESUMEN
BACKGROUND & AIMS: Enterochromaffin-like (ECL) cells in the stomach express gastrin/cholecystokinin 2 receptor CCK2R and are known to expand under hypergastrinemia, but whether this results from expansion of existing ECL cells or increased production from progenitors has not been clarified. METHODS: We used mice with green fluorescent protein fluorescent reporter expression in ECL cells (histidine decarboxylase [Hdc]-green fluorescent protein), as well as Cck2r- and Hdc-driven Tamoxifen inducible recombinase Cre (Cck2r-CreERT2, Hdc-CreERT2) mice combined with Rosa26Sor-tdTomato (R26-tdTomato) mice, and studied their expression and cell fate in the gastric corpus by using models of hypergastrinemia (gastrin infusion, omeprazole treatment). RESULTS: Hdc-GFP marked the majority of ECL cells, located in the lower third of the gastric glands. Hypergastrinemia led to expansion of ECL cells that was not restricted to the gland base, and promoted cellular proliferation (Ki67) in the gastric isthmus but not in basal ECL cells. Cck2r-CreERT2 mice marked most ECL cells, as well as scattered cell types located higher up in the glands, whose number was increased during hypergastrinemia. Cck2r-CreERT2+ isthmus progenitors, but not Hdc+ mature ECL cells, were the source of ECL cell hyperplasia during hypergastrinemia and could grow as 3-dimensional spheroids in vitro. Moreover, gastrin treatment in vitro promoted sphere formation from sorted Cck2r+Hdc- cells, and increased chromogranin A and phosphorylated- extracellular signal-regulated kinase expression in CCK2R-derived organoids. Gastrin activates extracellular signal-regulated kinase pathways in vivo and in vitro, and treatment with the Mitogen-activated protein kinase kinase 1 inhibitor U0126 blocked hypergastrinemia-mediated changes, including CCK2R-derived ECL cell hyperplasia in vivo as well as sphere formation and chromogranin A expression in vitro. CONCLUSIONS: We show here that hypergastrinemia induces ECL cell hyperplasia that is derived primarily from CCK2R+ progenitors in the corpus. Gastrin-dependent function of CCK2R+ progenitors is regulated by the extracellular signal-regulated kinase pathway.
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Células Similares a las Enterocromafines/patología , Mucosa Gástrica/patología , Gastrinas/sangre , Animales , Modelos Animales de Enfermedad , Células Similares a las Enterocromafines/metabolismo , Mucosa Gástrica/citología , Mucosa Gástrica/metabolismo , Gastrinas/metabolismo , Humanos , Hiperplasia/sangre , Hiperplasia/patología , Sistema de Señalización de MAP Quinasas , Ratones , Receptor de Colecistoquinina B/metabolismo , Células Madre/patologíaRESUMEN
The enteric neurotransmitter acetylcholine governs important intestinal epithelial secretory and immune functions through its actions on epithelial muscarinic Gq-coupled receptors such as M3R. Its role in the regulation of intestinal stem cell function and differentiation, however, has not been clarified. Here, we find that nonselective muscarinic receptor antagonism in mice as well as epithelial-specific ablation of M3R induces a selective expansion of DCLK1-positive tuft cells, suggesting a model of feedback inhibition. Cholinergic blockade reduces Lgr5-positive intestinal stem cell tracing and cell number. In contrast, Prox1-positive endocrine cells appear as primary sensors of cholinergic blockade inducing the expansion of tuft cells, which adopt an enteroendocrine phenotype and contribute to increased mucosal levels of acetylcholine. This compensatory mechanism is lost with acute irradiation injury, resulting in a paucity of tuft cells and acetylcholine production. Thus, enteroendocrine tuft cells appear essential to maintain epithelial homeostasis following modifications of the cholinergic intestinal niche.
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Acetilcolina/metabolismo , Proteínas de Homeodominio/metabolismo , Mucosa Intestinal/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Quinasas Similares a Doblecortina , Células Enteroendocrinas/metabolismo , Femenino , Proteínas de Homeodominio/genética , Mucosa Intestinal/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Neurotransmisores/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Proteínas Supresoras de Tumor/genéticaRESUMEN
Molecular signalling mediated by the phosphatidylinositol-3-kinase (PI3K)-Akt axis is a key regulator of cellular functions. Importantly, alteration of the PI3K-Akt signalling underlies the development of different human diseases, thus prompting the investigation of the pathway as a molecular target for pharmacologic intervention. In this regard, recent studies showed that small molecule inhibitors of PI3K, the upstream regulator of the pathway, reduced the development of inflammation during acute pancreatitis, a highly debilitating and potentially lethal disease. Here we investigated whether a specific reduction of Akt activity, by using either pharmacologic Akt inhibition, or genetic inactivation of the Akt1 isoform selectively in pancreatic acinar cells, is effective in ameliorating the onset and progression of the disease. We discovered that systemic reduction of Akt activity did not protect the pancreas from initial damage and only transiently delayed leukocyte recruitment. However, reduction of Akt activity decreased acinar proliferation and exacerbated acinar-to-ductal metaplasia (ADM) formation, two critical events in the progression of pancreatitis. These phenotypes were recapitulated upon conditional inactivation of Akt1 in acinar cells, which resulted in reduced expression of 4E-BP1, a multifunctional protein of key importance in cell proliferation and metaplasia formation. Collectively, our results highlight the critical role played by Akt1 during the development of acute pancreatitis in the control of acinar cell proliferation and ADM formation. In addition, these results harbour important translational implications as they raise the concern that inhibitors of PI3K-Akt signalling pathways may negatively affect the regeneration of the pancreas. Finally, this work provides the basis for further investigating the potential of Akt1 activators to boost pancreatic regeneration following inflammatory insults. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Células Acinares/enzimología , Proliferación Celular , Páncreas Exocrino/enzimología , Conductos Pancreáticos/enzimología , Pancreatitis/enzimología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Células Acinares/efectos de los fármacos , Células Acinares/patología , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ceruletida , Modelos Animales de Enfermedad , Masculino , Metaplasia , Ratones Endogámicos C57BL , Ratones Noqueados , Páncreas Exocrino/efectos de los fármacos , Páncreas Exocrino/patología , Conductos Pancreáticos/efectos de los fármacos , Conductos Pancreáticos/patología , Pancreatitis/inducido químicamente , Pancreatitis/genética , Pancreatitis/patología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/análisis , Proteínas Proto-Oncogénicas c-akt/deficiencia , Proteínas Proto-Oncogénicas c-akt/genética , Ratas , Transducción de SeñalRESUMEN
Proliferation of pancreatic acinar cells is a critical process in the pathophysiology of pancreatic diseases, because limited or defective proliferation is associated with organ dysfunction and patient morbidity. In this context, elucidating the signalling pathways that trigger and sustain acinar proliferation is pivotal to develop therapeutic interventions promoting the regenerative process of the organ. In this study we used genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones to elucidate their role in acinar proliferation following caerulein-mediated acute pancreatitis in mice. In addition, molecular mechanisms mediating the effects of thyroid hormones were identified by genetic and pharmacological inactivation of selected signalling pathways.In this study we demonstrated that levels of the thyroid hormone 3,3',5-triiodo-l-thyronine (T3) transiently increased in the pancreas during acute pancreatitis. Moreover, by using genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones, we showed that T3 was required to promote proliferation of pancreatic acinar cells, without affecting the extent of tissue damage or inflammatory infiltration.Finally, upon genetic and pharmacological inactivation of selected signalling pathways, we demonstrated that T3 exerted its mitogenic effect on acinar cells via a tightly controlled action on different molecular effectors, including histone deacetylase, AKT, and TGFß signalling.In conclusion, our data suggest that local availability of T3 in the pancreas is required to promote acinar cell proliferation and provide the rationale to exploit thyroid hormone signalling to enhance pancreatic regeneration. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Asunto(s)
Células Acinares/metabolismo , Proliferación Celular , Hipertiroidismo/metabolismo , Páncreas Exocrino/metabolismo , Pancreatitis/metabolismo , Triyodotironina/metabolismo , Células Acinares/patología , Animales , Ceruletida , Modelos Animales de Enfermedad , Histona Desacetilasas/metabolismo , Hipertiroidismo/genética , Hipertiroidismo/patología , Yoduro Peroxidasa/deficiencia , Yoduro Peroxidasa/genética , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Páncreas Exocrino/patología , Pancreatitis/inducido químicamente , Pancreatitis/genética , Pancreatitis/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptor Tipo II de Factor de Crecimiento Transformador beta/deficiencia , Receptor Tipo II de Factor de Crecimiento Transformador beta/genética , Transducción de Señal , Tiroxina/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Regulación hacia ArribaRESUMEN
Pancreatic ductal adenocarcinoma (PDAC), which is the primary cause of pancreatic cancer mortality, is poorly responsive to currently available interventions. Identifying new targets that drive PDAC formation and progression is critical for developing alternative therapeutic strategies to treat this lethal malignancy. Using genetic and pharmacological approaches, we investigated in vivo and in vitro whether uptake of the monoamine serotonin [5-hydroxytryptamine (5-HT)] is required for PDAC development. We demonstrated that pancreatic acinar cells have the ability to readily take up 5-HT in a transport-mediated manner. 5-HT uptake promoted activation of the small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1), which is required for transdifferentiation of acinar cells into acinar-to-ductal metaplasia (ADM), a key determinant in PDAC development. Consistent with the central role played by Rac1 in ADM formation, inhibition of the 5-HT transporter Sert (Slc6a4) with fluoxetine reduced ADM formation both in vitro and in vivo in a cell-autonomous manner. In addition, fluoxetine treatment profoundly compromised the stromal reaction and affected the proliferation and lipid metabolism of malignant PDAC cells. We propose that Sert is a promising therapeutic target to counteract the early event of ADM, with the potential to stall the initiation and progression of pancreatic carcinogenesis. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Asunto(s)
Carcinoma Ductal Pancreático/enzimología , Proliferación Celular , Genes ras , Neuropéptidos/metabolismo , Páncreas/enzimología , Neoplasias Pancreáticas/enzimología , Serotonina/metabolismo , Proteína de Unión al GTP rac1/metabolismo , Animales , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Carcinoma Ductal Pancreático/prevención & control , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Transdiferenciación Celular , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Embrión de Pollo , Modelos Animales de Enfermedad , Activación Enzimática , Fluoxetina/farmacología , Predisposición Genética a la Enfermedad , Humanos , Metaplasia , Ratones Endogámicos C57BL , Ratones Transgénicos , Neovascularización Patológica , Páncreas/efectos de los fármacos , Páncreas/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/prevención & control , Fenotipo , Ratas , Proteínas de Transporte de Serotonina en la Membrana Plasmática/efectos de los fármacos , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismo , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Transducción de Señal , Triptófano Hidroxilasa/genética , Triptófano Hidroxilasa/metabolismoRESUMEN
Adult pancreatic acinar cells have the ability to re-enter the cell cycle and proliferate upon injury or tissue loss. Despite this mitotic ability, the extent of acinar proliferation is often limited and unable to completely regenerate the injured tissue or restore the initial volume of the organ, thus leading to pancreatic dysfunction. Identifying molecular determinants of enhanced proliferation is critical to overcome this issue. In this study, we discovered that Murphy Roths Large (MRL/MpJ) mice can be exploited to identify molecular effectors promoting acinar proliferation upon injury, with the ultimate goal to develop therapeutic regimens to boost pancreatic regeneration. Our results show that, upon cerulein-induced acinar injury, cell proliferation was enhanced and cell cycle components up-regulated in the pancreas of MRL/MpJ mice compared to the control strain C57BL/6. Initial damage of acinar cells was exacerbated in these mice, manifested by increased serum levels of pancreatic enzymes, intra-pancreatic trypsinogen activation and acinar cell apoptosis. In addition, MRL/MpJ pancreata presented enhanced inflammation, de-differentiation of acinar cells and acinar-to-ductal metaplasia. Manipulation of inflammatory levels and mitogenic stimulation with the thyroid hormone 5,3-L-tri-iodothyronine revealed that factors derived from initial acinar injury rather than inflammatory injury promote the replicative advantage in MRL/MpJ mice.