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1.
Nat Immunol ; 24(9): 1443-1457, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37563309

RESUMO

Tissue-resident macrophages (TRMs) are long-lived cells that maintain locally and can be phenotypically distinct from monocyte-derived macrophages. Whether TRMs and monocyte-derived macrophages have district roles under differing pathologies is not understood. Here, we showed that a substantial portion of the macrophages that accumulated during pancreatitis and pancreatic cancer in mice had expanded from TRMs. Pancreas TRMs had an extracellular matrix remodeling phenotype that was important for maintaining tissue homeostasis during inflammation. Loss of TRMs led to exacerbation of severe pancreatitis and death, due to impaired acinar cell survival and recovery. During pancreatitis, TRMs elicited protective effects by triggering the accumulation and activation of fibroblasts, which was necessary for initiating fibrosis as a wound healing response. The same TRM-driven fibrosis, however, drove pancreas cancer pathogenesis and progression. Together, these findings indicate that TRMs play divergent roles in the pathogenesis of pancreatitis and cancer through regulation of stromagenesis.


Assuntos
Pâncreas , Pancreatite , Camundongos , Animais , Pâncreas/patologia , Macrófagos , Pancreatite/genética , Pancreatite/patologia , Fibrose , Neoplasias Pancreáticas
2.
EMBO J ; 43(13): 2530-2551, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38773319

RESUMO

A pervasive view is that undifferentiated stem cells are alone responsible for generating all other cells and are the origins of cancer. However, emerging evidence demonstrates fully differentiated cells are plastic, can be coaxed to proliferate, and also play essential roles in tissue maintenance, regeneration, and tumorigenesis. Here, we review the mechanisms governing how differentiated cells become cancer cells. First, we examine the unique characteristics of differentiated cell division, focusing on why differentiated cells are more susceptible than stem cells to accumulating mutations. Next, we investigate why the evolution of multicellularity in animals likely required plastic differentiated cells that maintain the capacity to return to the cell cycle and required the tumor suppressor p53. Finally, we examine an example of an evolutionarily conserved program for the plasticity of differentiated cells, paligenosis, which helps explain the origins of cancers that arise in adults. Altogether, we highlight new perspectives for understanding the development of cancer and new strategies for preventing carcinogenic cellular transformations from occurring.


Assuntos
Diferenciação Celular , Neoplasias , Humanos , Animais , Neoplasias/patologia , Neoplasias/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Células-Tronco , Carcinogênese/patologia
3.
Cell ; 155(2): 357-68, 2013 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-24120136

RESUMO

Proliferation of the self-renewing epithelium of the gastric corpus occurs almost exclusively in the isthmus of the glands, from where cells migrate bidirectionally toward pit and base. The isthmus is therefore generally viewed as the stem cell zone. We find that the stem cell marker Troy is expressed at the gland base by a small subpopulation of fully differentiated chief cells. By lineage tracing with a Troy-eGFP-ires-CreERT2 allele, single marked chief cells are shown to generate entirely labeled gastric units over periods of months. This phenomenon accelerates upon tissue damage. Troy(+) chief cells can be cultured to generate long-lived gastric organoids. Troy marks a specific subset of chief cells that display plasticity in that they are capable of replenishing entire gastric units, essentially serving as quiescent "reserve" stem cells. These observations challenge the notion that stem cell hierarchies represent a "one-way street."


Assuntos
Celulas Principais Gástricas/citologia , Células-Tronco/citologia , Estômago/citologia , Animais , Linhagem da Célula , Celulas Principais Gástricas/química , Mucosa Gástrica/citologia , Camundongos , Organoides/citologia , Receptores do Fator de Necrose Tumoral/análise , Via de Sinalização Wnt
4.
Annu Rev Physiol ; 84: 461-483, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-34705482

RESUMO

Complex multicellular organisms have evolved specific mechanisms to replenish cells in homeostasis and during repair. Here, we discuss how emerging technologies (e.g., single-cell RNA sequencing) challenge the concept that tissue renewal is fueled by unidirectional differentiation from a resident stem cell. We now understand that cell plasticity, i.e., cells adaptively changing differentiation state or identity, is a central tissue renewal mechanism. For example, mature cells can access an evolutionarily conserved program (paligenosis) to reenter the cell cycle and regenerate damaged tissue. Most tissues lack dedicated stem cells and rely on plasticity to regenerate lost cells. Plasticity benefits multicellular organisms, yet it also carries risks. For one, when long-lived cells undergo paligenotic, cyclical proliferation and redif-ferentiation, they can accumulate and propagate acquired mutations that activate oncogenes and increase the potential for developing cancer. Lastly, we propose a new framework for classifying patterns of cell proliferation in homeostasis and regeneration, with stem cells representing just one of the diverse methods that adult tissues employ.


Assuntos
Plasticidade Celular , Células-Tronco , Ciclo Celular/fisiologia , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Humanos , Regeneração/fisiologia
5.
Genes Dev ; 31(2): 154-171, 2017 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-28174210

RESUMO

We hypothesized that basic helix-loop-helix (bHLH) MIST1 (BHLHA15) is a "scaling factor" that universally establishes secretory morphology in cells that perform regulated secretion. Here, we show that targeted deletion of MIST1 caused dismantling of the secretory apparatus of diverse exocrine cells. Parietal cells (PCs), whose function is to pump acid into the stomach, normally lack MIST1 and do not perform regulated secretion. Forced expression of MIST1 in PCs caused them to expand their apical cytoplasm, rearrange mitochondrial/lysosome trafficking, and generate large secretory granules. Mist1 induced a cohort of genes regulated by MIST1 in multiple organs but did not affect PC function. MIST1 bound CATATG/CAGCTG E boxes in the first intron of genes that regulate autophagosome/lysosomal degradation, mitochondrial trafficking, and amino acid metabolism. Similar alterations in cell architecture and gene expression were also caused by ectopically inducing MIST1 in vivo in hepatocytes. Thus, MIST1 is a scaling factor necessary and sufficient by itself to induce and maintain secretory cell architecture. Our results indicate that, whereas mature cell types in each organ may have unique developmental origins, cells performing similar physiological functions throughout the body share similar transcription factor-mediated architectural "blueprints."


Assuntos
Regulação da Expressão Gênica/genética , Fator de Crescimento de Hepatócito/genética , Fator de Crescimento de Hepatócito/metabolismo , Células Parietais Gástricas/citologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Via Secretória/genética , Células Acinares/citologia , Células Acinares/efeitos dos fármacos , Células Acinares/metabolismo , Animais , Antineoplásicos Hormonais/farmacologia , Linhagem Celular , Expressão Ectópica do Gene/efeitos dos fármacos , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Células Parietais Gástricas/efeitos dos fármacos , Células Parietais Gástricas/metabolismo , Células Parietais Gástricas/ultraestrutura , Tamoxifeno/farmacologia
6.
Am J Physiol Gastrointest Liver Physiol ; 326(3): G205-G215, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38193187

RESUMO

Single-cell RNA-sequencing (scRNA-seq) has emerged as a powerful technique to identify novel cell markers, developmental trajectories, and transcriptional changes during cell differentiation and disease onset and progression. In this review, we highlight recent scRNA-seq studies of the gastric corpus in both human and murine systems that have provided insight into gastric organogenesis, identified novel markers for the various gastric lineages during development and in adults, and revealed transcriptional changes during regeneration and tumorigenesis. Overall, by elucidating transcriptional states and fluctuations at the cellular level in healthy and disease contexts, scRNA-seq may lead to better, more personalized clinical treatments for disease progression.


Assuntos
Análise de Célula Única , Estômago , Adulto , Humanos , Animais , Camundongos , Diferenciação Celular , Análise de Célula Única/métodos , Análise de Sequência de RNA/métodos , Perfilação da Expressão Gênica/métodos
7.
Am J Physiol Gastrointest Liver Physiol ; 326(5): G504-G524, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38349111

RESUMO

Genotoxic agents such as doxorubicin (DXR) can cause damage to the intestines that can be ameliorated by fasting. How fasting is protective and the optimal timing of fasting and refeeding remain unclear. Here, our analysis of fasting/refeeding-induced global intestinal transcriptional changes revealed metabolic shifts and implicated the cellular energetic hub mechanistic target of rapamycin complex 1 (mTORC1) in protecting from DXR-induced DNA damage. Our analysis of specific transcripts and proteins in intestinal tissue and tissue extracts showed that fasting followed by refeeding at the time of DXR administration reduced damage and caused a spike in mTORC1 activity. However, continued fasting after DXR prevented the mTORC1 spike and damage reduction. Surprisingly, the mTORC1 inhibitor, rapamycin, did not block fasting/refeeding-induced reduction in DNA damage, suggesting that increased mTORC1 is dispensable for protection against the initial DNA damage response. In Ddit4-/- mice [DDIT4 (DNA-damage-inducible transcript 4) functions to regulate mTORC1 activity], fasting reduced DNA damage and increased intestinal crypt viability vs. ad libitum-fed Ddit4-/- mice. Fasted/refed Ddit4-/- mice maintained body weight, with increased crypt proliferation by 5 days post-DXR, whereas ad libitum-fed Ddit4-/- mice continued to lose weight and displayed limited crypt proliferation. Genes encoding epithelial stem cell and DNA repair proteins were elevated in DXR-injured, fasted vs. ad libitum Ddit4-/- intestines. Thus, fasting strongly reduced intestinal damage when normal dynamic regulation of mTORC1 was lost. Overall, the results confirm that fasting protects the intestines against DXR and suggests that fasting works by pleiotropic - including both mTORC1-dependent and independent - mechanisms across the temporally dynamic injury response.NEW & NOTEWORTHY New findings are 1) DNA damage reduction following a 24-h fast depends on the timing of postfast refeeding in relation to chemotherapy initiation; 2) fasting/refeeding-induced upregulation of mTORC1 activity is not required for early (6 h) protection against DXR-induced DNA damage; and 3) fasting increases expression of intestinal stem cell and DNA damage repair genes, even when mTORC1 is dysregulated, highlighting fasting's crucial role in regulating mTORC1-dependent and independent mechanisms in the dynamic recovery process.


Assuntos
Doxorrubicina , Intestino Delgado , Intestinos , Camundongos , Animais , Intestinos/fisiologia , Alvo Mecanístico do Complexo 1 de Rapamicina , Adutos de DNA , Jejum/fisiologia
8.
Development ; 148(3)2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547203

RESUMO

In October 2020, the Keystone Symposia Global Health Series hosted a Keystone eSymposia entitled 'Tissue Plasticity: Preservation and Alteration of Cellular Identity'. The event synthesized groundbreaking research from unusually diverse fields of study, presented in various formats, including live and virtual talks, panel discussions and interactive e-poster sessions. The meeting focused on cell identity changes and plasticity in multiple tissues, species and developmental contexts, both in homeostasis and during injury. Here, we review the key themes of the meeting: (1) cell-extrinsic drivers of plasticity; (2) epigenomic regulation of cell plasticity; and (3) conserved mechanisms governing plasticity. A salient take-home conclusion was that there may be conserved mechanisms used by cells to execute plasticity, with autodegradative activity (autophagy and lysosomes) playing a crucial initial step in diverse organs and organisms.


Assuntos
Plasticidade Celular/efeitos dos fármacos , Plasticidade Celular/fisiologia , Cimentos de Resina/farmacologia , Animais , Transdiferenciação Celular/fisiologia , Reprogramação Celular/fisiologia , Homeostase , Humanos , Metaplasia
9.
EMBO J ; 38(19): e103148, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31475380

RESUMO

It is now recognized that cell identity is more fluid, and tissues more plastic, than previously thought. The plasticity of cells is relevant to diverse fields, most notably developmental and stem cell biology, regenerative medicine, and cancer biology. To date, a comprehensive and uniform nomenclature to define distinct cell states and their injury-induced interconversions has been elusive. The first Keystone Symposium devoted exclusively to cellular plasticity in regeneration and tumorigenesis was held on January 2019 in Keystone, Colorado, and featured a workshop on terminology in the cell plasticity field. Definitions for terms such as plasticity, de- and transdifferentiation, reversion, and paligenosis were discussed. Here, we summarize the content and tenor of the symposium and nomenclature-focused workshop with regard to terms in the field. We outline the challenges with current definitions and recommend best practices and approaches to developing an accurate and acceptable nomenclature in the future.


Assuntos
Plasticidade Celular , Terminologia como Assunto , Animais , Carcinogênese , Congressos como Assunto , Humanos , Plásticos , Medicina Regenerativa
10.
Gastroenterology ; 162(2): 415-430, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34728185

RESUMO

The mucosa of the body of the stomach (ie, the gastric corpus) uses 2 overlapping, depth-dependent mechanisms to respond to injury. Superficial injury heals via surface cells with histopathologic changes like foveolar hyperplasia. Deeper, usually chronic, injury/inflammation, most frequently induced by the carcinogenic bacteria Helicobacter pylori, elicits glandular histopathologic alterations, initially manifesting as pyloric (also known as pseudopyloric) metaplasia. In this pyloric metaplasia, corpus glands become antrum (pylorus)-like with loss of acid-secreting parietal cells (atrophic gastritis), expansion of foveolar cells, and reprogramming of digestive enzyme-secreting chief cells into deep antral gland-like mucous cells. After acute parietal cell loss, chief cells can reprogram through an orderly stepwise progression (paligenosis) initiated by interleukin-13-secreting innate lymphoid cells (ILC2s). First, massive lysosomal activation helps mitigate reactive oxygen species and remove damaged organelles. Second, mucus and wound-healing proteins (eg, TFF2) and other transcriptional alterations are induced, at which point the reprogrammed chief cells are recognized as mucus-secreting spasmolytic polypeptide-expressing metaplasia cells. In chronic severe injury, glands with pyloric metaplasia can harbor both actively proliferating spasmolytic polypeptide-expressing metaplasia cells and eventually intestine-like cells. Gastric glands with such lineage confusion (mixed incomplete intestinal metaplasia and proliferative spasmolytic polypeptide-expressing metaplasia) may be at particular risk for progression to dysplasia and cancer. A pyloric-like pattern of metaplasia after injury also occurs in other gastrointestinal organs including esophagus, pancreas, and intestines, and the paligenosis program itself seems broadly conserved across tissues and species. Here we discuss aspects of metaplasia in stomach, incorporating data derived from animal models and work on human cells and tissues in correlation with diagnostic and clinical implications.


Assuntos
Plasticidade Celular/fisiologia , Reprogramação Celular/fisiologia , Mucosa Gástrica/fisiologia , Regeneração/fisiologia , Estômago/fisiologia , Animais , Mucosa Gástrica/citologia , Mucosa Gástrica/patologia , Infecções por Helicobacter/fisiopatologia , Humanos , Hiperplasia , Metaplasia , Células Parietais Gástricas/fisiologia , Estômago/citologia , Estômago/patologia
11.
Gastroenterology ; 162(2): 604-620.e20, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34695382

RESUMO

BACKGROUND & AIMS: Acinar to ductal metaplasia (ADM) occurs in the pancreas in response to tissue injury and is a potential precursor for adenocarcinoma. The goal of these studies was to define the populations arising from ADM, the associated transcriptional changes, and markers of disease progression. METHODS: Acinar cells were lineage-traced with enhanced yellow fluorescent protein (EYFP) to follow their fate post-injury. Transcripts of more than 13,000 EYFP+ cells were determined using single-cell RNA sequencing (scRNA-seq). Developmental trajectories were generated. Data were compared with gastric metaplasia, KrasG12D-induced neoplasia, and human pancreatitis. Results were confirmed by immunostaining and electron microscopy. KrasG12D was expressed in injury-induced ADM using several inducible Cre drivers. Surgical specimens of chronic pancreatitis from 15 patients were evaluated by immunostaining. RESULTS: scRNA-seq of ADM revealed emergence of a mucin/ductal population resembling gastric pyloric metaplasia. Lineage trajectories suggest that some pyloric metaplasia cells can generate tuft and enteroendocrine cells (EECs). Comparison with KrasG12D-induced ADM identifies populations associated with disease progression. Activation of KrasG12D expression in HNF1B+ or POU2F3+ ADM populations leads to neoplastic transformation and formation of MUC5AC+ gastric-pit-like cells. Human pancreatitis samples also harbor pyloric metaplasia with a similar transcriptional phenotype. CONCLUSIONS: Under conditions of chronic injury, acinar cells undergo a pyloric-type metaplasia to mucinous progenitor-like populations, which seed disparate tuft cell and EEC lineages. ADM-derived EEC subtypes are diverse. KrasG12D expression is sufficient to drive neoplasia when targeted to injury-induced ADM populations and offers an alternative origin for tumorigenesis. This program is conserved in human pancreatitis, providing insight into early events in pancreas diseases.


Assuntos
Células Acinares/metabolismo , Carcinoma Ductal Pancreático/genética , Metaplasia/genética , Ductos Pancreáticos/metabolismo , Neoplasias Pancreáticas/genética , Células Acinares/citologia , Plasticidade Celular/genética , Células Enteroendócrinas/citologia , Células Enteroendócrinas/metabolismo , Perfilação da Expressão Gênica , Humanos , Metaplasia/metabolismo , Mucina-5AC/genética , Pâncreas/citologia , Pâncreas/metabolismo , Ductos Pancreáticos/citologia , Pancreatite/genética , Pancreatite/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Análise de Célula Única
12.
EMBO Rep ; 22(9): e51806, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34309175

RESUMO

Differentiated cells across multiple species and organs can re-enter the cell cycle to aid in injury-induced tissue regeneration by a cellular program called paligenosis. Here, we show that activating transcription factor 3 (ATF3) is induced early during paligenosis in multiple cellular contexts, transcriptionally activating the lysosomal trafficking gene Rab7b. ATF3 and RAB7B are upregulated in gastric and pancreatic digestive-enzyme-secreting cells at the onset of paligenosis Stage 1, when cells massively induce autophagic and lysosomal machinery to dismantle differentiated cell morphological features. Their expression later ebbs before cells enter mitosis during Stage 3. Atf3-/- mice fail to induce RAB7-positive autophagic and lysosomal vesicles, eventually causing increased death of cells en route to Stage 3. Finally, we observe that ATF3 is expressed in human gastric metaplasia and during paligenotic injury across multiple other organs and species. Thus, our findings indicate ATF3 is an evolutionarily conserved gene orchestrating the early paligenotic autodegradative events that must occur before cells are poised to proliferate and contribute to tissue repair.


Assuntos
Fator 3 Ativador da Transcrição , Plasticidade Celular , Fator 3 Ativador da Transcrição/genética , Animais , Ciclo Celular , Diferenciação Celular , Metaplasia/genética , Camundongos
13.
EMBO J ; 37(7)2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29467218

RESUMO

In 1900, Adami speculated that a sequence of context-independent energetic and structural changes governed the reversion of differentiated cells to a proliferative, regenerative state. Accordingly, we show here that differentiated cells in diverse organs become proliferative via a shared program. Metaplasia-inducing injury caused both gastric chief and pancreatic acinar cells to decrease mTORC1 activity and massively upregulate lysosomes/autophagosomes; then increase damage associated metaplastic genes such as Sox9; and finally reactivate mTORC1 and re-enter the cell cycle. Blocking mTORC1 permitted autophagy and metaplastic gene induction but blocked cell cycle re-entry at S-phase. In kidney and liver regeneration and in human gastric metaplasia, mTORC1 also correlated with proliferation. In lysosome-defective Gnptab-/- mice, both metaplasia-associated gene expression changes and mTORC1-mediated proliferation were deficient in pancreas and stomach. Our findings indicate differentiated cells become proliferative using a sequential program with intervening checkpoints: (i) differentiated cell structure degradation; (ii) metaplasia- or progenitor-associated gene induction; (iii) cell cycle re-entry. We propose this program, which we term "paligenosis", is a fundamental process, like apoptosis, available to differentiated cells to fuel regeneration following injury.


Assuntos
Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Regeneração/fisiologia , Células Acinares , Animais , Autofagossomos/fisiologia , Ciclo Celular/fisiologia , Transdiferenciação Celular/fisiologia , Reprogramação Celular/fisiologia , Celulas Principais Gástricas/patologia , Trato Gastrointestinal/patologia , Expressão Gênica , Humanos , Lisossomos , Metaplasia/genética , Camundongos , Camundongos Endogâmicos C57BL , Fase S/fisiologia , Fatores de Transcrição SOX9/metabolismo , Estômago/lesões , Estômago/patologia , Transferases (Outros Grupos de Fosfato Substituídos)/genética
14.
Am J Physiol Gastrointest Liver Physiol ; 322(1): G49-G65, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34816763

RESUMO

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). ELAPOR1 expression was lost as tissue injury caused ZCs to undergo paligenosis (i.e., to become metaplastic and reenter the cell cycle). In cultured cells, ELAPOR1 trafficked with cis-Golgi resident proteins and with the trans-Golgi and late endosome protein: cation-independent M6PR. Secretory vesicle trafficking was disrupted by expression of ELAPOR1 truncation mutants. Mass spectrometric analysis of co-immunoprecipitated proteins showed ELAPOR1 and CI-M6PR shared many binding partners. However, CI-M6PR and ELAPOR1 must function differently, as CI-M6PR co-immunoprecipitated more lysosomal proteins and was not decreased during paligenosis in vivo. We generated Elapor1-/- mice to determine ELAPOR1 function in vivo. Consistent with in vitro findings, secretory granule maturation was defective in Elapor1-/- ZCs. Our results identify a role for ELAPOR1 in secretory granule maturation and help clarify how a single transcription factor maintains mature exocrine cell architecture in homeostasis and helps dismantle it during paligenosis.NEW & NOTEWORTHY Here, we find the MIST1 (BHLHA15) transcriptional target ELAPOR1 is an evolutionarily conserved, trans-Golgi/late endosome M6PR domain-containing protein that is specific to gastric zymogenic cells and required for normal secretory granule maturation in human cell lines and in mouse stomach.


Assuntos
Células Epiteliais/metabolismo , Fator Promotor de Maturação/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Celulas Principais Gástricas/metabolismo , Endossomos/metabolismo , Humanos , Lisossomos/metabolismo , Fator Promotor de Maturação/genética , Camundongos , Pâncreas Exócrino/metabolismo , Fatores de Transcrição/metabolismo
15.
Gastroenterology ; 160(1): 260-271.e10, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956680

RESUMO

BACKGROUND AND AIMS: In stomach, metaplasia can arise from differentiated chief cells that become mitotic via paligenosis, a stepwise program. In paligenosis, mitosis initiation requires reactivation of the cellular energy hub mTORC1 after initial mTORC1 suppression by DNA damage induced transcript 4 (DDIT4 aka REDD1). Here, we use DDIT4-deficient mice and human cells to study how metaplasia increases tumorigenesis risk. METHODS: A tissue microarray of human gastric tissue specimens was analyzed by immunohistochemistry for DDIT4. C57BL/6 mice were administered combinations of intraperitoneal injections of high-dose tamoxifen (TAM) to induce spasmolytic polypeptide-expressing metaplasia (SPEM) and rapamycin to block mTORC1 activity, and N-methyl-N-nitrosourea (MNU) in drinking water to induce spontaneous gastric tumors. Stomachs were analyzed for proliferation, DNA damage, and tumor formation. CRISPR/Cas9-generated DDIT4-/- and control human gastric cells were analyzed for growth in vitro and in xenografts with and without 5-fluorouracil (5-FU) treatment. RESULTS: DDIT4 was expressed in normal gastric chief cells in mice and humans and decreased as chief cells became metaplastic. Paligenotic Ddit4-/- chief cells maintained constitutively high mTORC1, causing increased mitosis of metaplastic cells despite DNA damage. Lower DDIT4 expression correlated with longer survival of patients with gastric cancer. 5-FU-treated DDIT4-/- human gastric epithelial cells had significantly increased cells entering mitosis despite DNA damage and increased proliferation in vitro and in xenografts. MNU-treated Ddit4-/- mice had increased spontaneous tumorigenesis after multiple rounds of paligenosis induced by TAM. CONCLUSIONS: During injury-induced metaplastic proliferation, failure of licensing mTORC1 reactivation correlates with increased proliferation of cells harboring DNA damage, as well as increased tumor formation and growth in mice and humans.


Assuntos
Celulas Principais Gástricas/patologia , Metaplasia/etiologia , Metaplasia/patologia , Fatores de Transcrição/fisiologia , Animais , Carcinogênese , Técnicas de Cultura de Células , Proliferação de Células , Humanos , Camundongos , Camundongos Endogâmicos C57BL
16.
Gastroenterology ; 160(1): 302-316.e7, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33010253

RESUMO

BACKGROUND & AIMS: Interleukin (IL)33/IL1F11 is an important mediator for the development of type 2 T-helper cell (Th2)-driven inflammatory disorders and has also been implicated in the pathogenesis of gastrointestinal (GI)-related cancers, including gastric carcinoma. We therefore sought to mechanistically determine IL33's potential role as a critical factor linking chronic inflammation and gastric carcinogenesis using gastritis-prone SAMP1/YitFc (SAMP) mice. METHODS: SAMP and (parental control) AKR mice were assessed for baseline gastritis and progression to metaplasia. Expression/localization of IL33 and its receptor, ST2/IL1R4, were characterized in corpus tissues, and activation and neutralization studies were both performed targeting the IL33/ST2 axis. Dissection of immune pathways leading to metaplasia was evaluated, including eosinophil depletion studies using anti-IL5/anti-CCR3 treatment. RESULTS: Progressive gastritis and, ultimately, intestinalized spasmolytic polypeptide-expressing metaplasia (SPEM) was detected in SAMP stomachs, which was absent in AKR but could be moderately induced with exogenous, recombinant IL33. Robust peripheral (bone marrow) expansion of eosinophils and local recruitment of both eosinophils and IL33-expressing M2 macrophages into corpus tissues were evident in SAMP. Interestingly, IL33 blockade did not affect bone marrow-derived expansion and local infiltration of eosinophils, but markedly decreased M2 macrophages and SPEM features, while eosinophil depletion caused a significant reduction in both local IL33-producing M2 macrophages and SPEM in SAMP. CONCLUSIONS: IL33 promotes metaplasia and the sequelae of eosinophil-dependent downstream infiltration of IL33-producing M2 macrophages leading to intestinalized SPEM in SAMP, suggesting that IL33 represents a critical link between chronic gastritis and intestinalizing metaplasia that may serve as a potential therapeutic target for preneoplastic conditions of the GI tract.


Assuntos
Gastrite/etiologia , Gastrite/patologia , Interleucina-33/fisiologia , Neoplasias Gástricas/etiologia , Neoplasias Gástricas/patologia , Animais , Doença Crônica , Modelos Animais de Doenças , Eosinófilos , Mucosa Gástrica/patologia , Metaplasia , Camundongos
17.
Am J Gastroenterol ; 117(10): 1583-1592, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35970814

RESUMO

INTRODUCTION: Radiofrequency ablation (RFA) of Barrett's esophagus (BE) inflicts a wound spanning 3 epithelial types (stratified squamous, Barrett's metaplasia, gastric epithelium), yet the esophageal injury heals almost completely with squamous epithelium. Knowledge of how this unique wound heals might elucidate mechanisms underlying esophageal metaplasia. We aimed to prospectively and systematically characterize the early endoscopic and histologic features of RFA wound healing. METHODS: Patients with nondysplastic BE had endoscopy with systematic esophageal photographic mapping, biopsy, and volumetric laser endomicroscopy performed before and at 1, 2, and 4 weeks after RFA. RESULTS: Seven patients (6 men; mean age 56.1 ± 10.9 years) completed this study. Squamous re-epithelialization of RFA wounds did not only progress exclusively through squamous cells extending from the proximal wound edge but also progressed through islands of squamous epithelium sprouting throughout the ablated segment. Volumetric laser endomicroscopy revealed significant post-RFA increases in subepithelial glandular structures associated with the squamous islands. In 2 patients, biopsies of such islands revealed newly forming squamous epithelium contiguous with immature-appearing squamous cells arising from esophageal submucosal gland ducts. Subsquamous intestinal metaplasia (SSIM) was found in biopsies at 2 and/or 4 weeks after RFA in 6 of 7 patients. DISCUSSION: RFA wounds in BE are re-epithelialized, not just by squamous cells from the proximal wound margin but by scattered squamous islands in which esophageal submucosal gland duct cells seem to redifferentiate into the squamous progenitors that fuel squamous re-epithelialization. SSIM can be found in most patients during the healing process. We speculate that this SSIM might underlie Barrett's recurrences after apparently successful eradication.


Assuntos
Esôfago de Barrett , Carcinoma de Células Escamosas , Ablação por Cateter , Neoplasias Esofágicas , Idoso , Esôfago de Barrett/patologia , Carcinoma de Células Escamosas/cirurgia , Neoplasias Esofágicas/patologia , Esofagoscopia , Humanos , Masculino , Metaplasia/complicações , Pessoa de Meia-Idade , Cicatrização
18.
Gastroenterology ; 158(3): 598-609.e5, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31589873

RESUMO

BACKGROUND & AIMS: Adult zymogen-producing (zymogenic) chief cells (ZCs) in the mammalian gastric gland base are believed to arise from descending mucous neck cells, which arise from stem cells. Gastric injury, such as from Helicobacter pylori infection in patients with chronic atrophic gastritis, can cause metaplasia, characterized by gastric cell expression of markers of wound-healing; these cells are called spasmolytic polypeptide-expressing metaplasia (SPEM) cells. We investigated differentiation and proliferation patterns of neck cells, ZCs, and SPEM cells in mice. METHODS: C57BL/6 mice were given intraperitoneal injections of high-dose tamoxifen to induce SPEM or gavaged with H pylori (PMSS1) to induce chronic gastric injury. Mice were then given pulses of 5-bromo-2'-deoxyuridine (BrdU) in their drinking water, followed by chase periods without BrdU, or combined with intraperitoneal injections of 5-ethynyl-2'-deoxyuridine. We collected gastric tissues and performed immunofluorescence and immunohistochemical analyses to study gastric cell proliferation, differentiation, and turnover. RESULTS: After 8 weeks of continuous BrdU administration, fewer than 10% of homeostatic ZCs incorporated BrdU, whereas 88% of neck cells were labeled. In pulse-chase experiments, various chase periods decreased neck cell label but did not increase labeling of ZCs. When mice were given BrdU at the same time as tamoxifen, more than 90% of cells were labeled in all gastric lineages. After 3 months' recovery (no tamoxifen), ZCs became the predominant BrdU-labeled population, whereas other cells, including neck cells, were mostly negative. When we tracked the labeled cells in such mice over time, we observed that the proportion of BrdU-positive ZCs remained greater than 60% up to 11 months. In mice whose ZCs were the principal BrdU-positive population, acute injury by tamoxifen or chronic injury by H pylori infection resulted in SPEM cells becoming the principal BrdU-positive population. After withdrawal of tamoxifen, BrdU-positive ZCs reappeared. CONCLUSIONS: We studied mice in homeostasis or with tamoxifen- or H pylori-induced SPEM. Our findings indicated that mucous neck cells do not contribute substantially to generation of ZCs during homeostasis and that ZCs maintain their own census, likely through infrequent self-replication. After metaplasia-inducing injury, ZCs can become SPEM cells, and then redifferentiate into ZCs on injury resolution.


Assuntos
Diferenciação Celular , Proliferação de Células , Celulas Principais Gástricas/patologia , Celulas Principais Gástricas/fisiologia , Mucosa Gástrica/patologia , Animais , Bromodesoxiuridina , Feminino , Imunofluorescência , Mucosa Gástrica/metabolismo , Infecções por Helicobacter/complicações , Helicobacter pylori , Homeostase , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Metaplasia/etiologia , Metaplasia/metabolismo , Metaplasia/patologia , Metaplasia/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Tamoxifeno
19.
Gastroenterology ; 159(6): 2116-2129.e4, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32835664

RESUMO

BACKGROUND & AIMS: Chronic atrophic gastritis can lead to gastric metaplasia and increase risk of gastric adenocarcinoma. Metaplasia is a precancerous lesion associated with an increased risk for carcinogenesis, but the mechanism(s) by which inflammation induces metaplasia are poorly understood. We investigated transcriptional programs in mucous neck cells and chief cells as they progress to metaplasia mice with chronic gastritis. METHODS: We analyzed previously generated single-cell RNA-sequencing (scRNA-seq) data of gastric corpus epithelium to define transcriptomes of individual epithelial cells from healthy BALB/c mice (controls) and TxA23 mice, which have chronically inflamed stomachs with metaplasia. Chronic gastritis was induced in B6 mice by Helicobacter pylori infection. Gastric tissues from mice and human patients were analyzed by immunofluorescence to verify findings at the protein level. Pseudotime trajectory analysis of scRNA-seq data was used to predict differentiation of normal gastric epithelium to metaplastic epithelium in chronically inflamed stomachs. RESULTS: Analyses of gastric epithelial transcriptomes revealed that gastrokine 3 (Gkn3) mRNA is a specific marker of mouse gastric corpus metaplasia (spasmolytic polypeptide expressing metaplasia, SPEM). Gkn3 mRNA was undetectable in healthy gastric corpus; its expression in chronically inflamed stomachs (from TxA23 mice and mice with Helicobacter pylori infection) identified more metaplastic cells throughout the corpus than previously recognized. Staining of healthy and diseased human gastric tissue samples paralleled these results. Although mucous neck cells and chief cells from healthy stomachs each had distinct transcriptomes, in chronically inflamed stomachs, these cells had distinct transcription patterns that converged upon a pre-metaplastic pattern, which lacked the metaplasia-associated transcripts. Finally, pseudotime trajectory analysis confirmed the convergence of mucous neck cells and chief cells into a pre-metaplastic phenotype that ultimately progressed to metaplasia. CONCLUSIONS: In analyses of tissues from chronically inflamed stomachs of mice and humans, we expanded the definition of gastric metaplasia to include Gkn3 mRNA and GKN3-positive cells in the corpus, allowing a more accurate assessment of SPEM. Under conditions of chronic inflammation, chief cells and mucous neck cells are plastic and converge into a pre-metaplastic cell type that progresses to metaplasia.


Assuntos
Celulas Principais Gástricas/patologia , Gastrite Atrófica/imunologia , Infecções por Helicobacter/imunologia , Lesões Pré-Cancerosas/diagnóstico , Neoplasias Gástricas/prevenção & controle , Animais , Biomarcadores/análise , Biomarcadores/metabolismo , Carcinogênese/genética , Carcinogênese/imunologia , Proteínas de Transporte/análise , Proteínas de Transporte/metabolismo , Celulas Principais Gástricas/imunologia , Modelos Animais de Doenças , Feminino , Gastrite Atrófica/microbiologia , Gastrite Atrófica/patologia , Infecções por Helicobacter/genética , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/imunologia , Humanos , Masculino , Proteínas de Membrana/análise , Proteínas de Membrana/metabolismo , Metaplasia/diagnóstico , Metaplasia/genética , Metaplasia/imunologia , Metaplasia/patologia , Camundongos , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/imunologia , Lesões Pré-Cancerosas/patologia , RNA-Seq , Análise de Célula Única , Neoplasias Gástricas/patologia
20.
RNA ; 25(1): 70-81, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30309881

RESUMO

Mammalian C to U RNA is mediated by APOBEC1, the catalytic deaminase, together with RNA binding cofactors (including A1CF and RBM47) whose relative physiological requirements are unresolved. Although A1CF complements APOBEC1 for in vitro RNA editing, A1cf-/- mice exhibited no change in apolipoproteinB (apoB) RNA editing, while Rbm47 mutant mice exhibited impaired intestinal RNA editing of apoB as well as other targets. Here we examined the role of A1CF and RBM47 in adult mouse liver and intestine, following deletion of either one or both gene products and also following forced (liver or intestinal) transgenic A1CF expression. There were minimal changes in hepatic and intestinal apoB RNA editing in A1cf-/- mice and no changes in either liver- or intestine-specific A1CF transgenic mice. Rbm47 liver-specific knockout (Rbm47LKO ) mice demonstrated reduced editing in a subset (11 of 20) of RNA targets, including apoB. By contrast, apoB RNA editing was virtually eliminated (<6% activity) in intestine-specific (Rbm47IKO ) mice with only five of 53 targets exhibiting C-to-U RNA editing. Double knockout of A1cf and Rbm47 in liver (ARLKO ) eliminated apoB RNA editing and reduced editing in the majority of other targets, with no changes following adenoviral APOBEC1 administration. Intestinal double knockout mice (ARIKO ) demonstrated further reduced editing (<10% activity) in four of five of the residual APOBEC1 targets identified in ARIKO mice. These data suggest that A1CF and RBM47 each function independently, yet interact in a tissue-specific manner, to regulate the activity and site selection of APOBEC1 dependent C-to-U RNA editing.


Assuntos
Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Edição de RNA , Proteínas de Ligação a RNA/metabolismo , Desaminase APOBEC-1/genética , Desaminase APOBEC-1/metabolismo , Animais , Sequência de Bases , Técnicas de Inativação de Genes , Ribonucleoproteínas Nucleares Heterogêneas/deficiência , Ribonucleoproteínas Nucleares Heterogêneas/genética , Mucosa Intestinal/metabolismo , Fígado/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Especificidade de Órgãos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética
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