Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Filtros adicionais











Tipo de estudo
Intervalo de ano
1.
Traffic ; 19(11): 879-892, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30095213

RESUMO

Deficiency in diacylglycerol acyltransferase (DGAT1) is a rare cause of neonatal diarrhea, without a known mechanism or in vitro model. A patient presenting at our institution at 7 weeks of life with failure to thrive and diarrhea was found by whole-exome sequencing to have a homozygous DGAT1 truncation mutation. Duodenal biopsies showed loss of DGAT1 and deficits in apical membrane transporters and junctional proteins in enterocytes. When placed on a very low-fat diet, the patient's diarrhea resolved with normalization of brush border transporter localization in endoscopic biopsies. DGAT1 knockdown in Caco2-BBe cells modeled the deficits in apical trafficking, with loss of apical DPPIV and junctional occludin. Elevation in cellular lipid levels, including diacylglycerol (DAG) and phospholipid metabolites of DAG, was documented by lipid analysis in DGAT1 knockdown cells. Culture of the DGAT1 knockdown cells in lipid-depleted media led to re-establishment of occludin and return of apical DPPIV. DGAT1 loss appears to elicit global changes in enterocyte polarized trafficking that could account for deficits in absorption seen in the patient. The in vitro modeling of this disease should allow for investigation of possible therapeutic targets.

2.
Gastroenterology ; 155(6): 1883-1897.e10, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30144427

RESUMO

BACKGROUND & AIMS: Inactivating mutations in MYO5B cause microvillus inclusion disease (MVID), but the physiological cause of the diarrhea associated with this disease is unclear. We investigated whether loss of MYO5B results in aberrant expression of apical enterocyte transporters. METHODS: We studied alterations in apical membrane transporters in MYO5B-knockout mice, as well as mice with tamoxifen-inducible, intestine-specific disruption of Myo5b (VilCreERT2;Myo5bflox/flox mice) or those not given tamoxifen (controls). Intestinal tissues were collected from mice and analyzed by immunostaining, immunoelectron microscopy, or cultured enteroids were derived. Functions of brush border transporters in intestinal mucosa were measured in Ussing chambers. We obtained duodenal biopsy specimens from individuals with MVID and individuals without MVID (controls) and compared transporter distribution by immunocytochemistry. RESULTS: Compared to intestinal tissues from littermate controls, intestinal tissues from MYO5B-knockout mice had decreased apical localization of SLC9A3 (also called NHE3), SLC5A1 (also called SGLT1), aquaporin (AQP) 7, and sucrase isomaltase, and subapical localization of intestinal alkaline phosphatase and CDC42. However, CFTR was present on apical membranes of enterocytes from MYO5B knockout and control mice. Intestinal biopsies from patients with MVID had subapical localization of NHE3, SGLT1, and AQP7, but maintained apical CFTR. After tamoxifen administration, VilCreERT2;Myo5bflox/flox mice lost apical NHE3, SGLT1, DRA, and AQP7, similar to germline MYO5B knockout mice. Intestinal tissues from VilCreERT2;Myo5bflox/flox mice had increased CFTR in crypts and CFTR localized to the apical membranes of enterocytes. Intestinal mucosa from VilCreERT2;Myo5bflox/flox mice given tamoxifen did not have an intestinal barrier defect, based on Ussing chamber analysis, but did have decreased SGLT1 activity and increased CFTR activity. CONCLUSIONS: Although trafficking of many apical transporters is regulated by MYO5B, trafficking of CFTR is largely independent of MYO5B. Decreased apical localization of NHE3, SGLT1, DRA, and AQP7 might be responsible for dysfunctional water absorption in enterocytes of patients with MVID. Maintenance of apical CFTR might exacerbate water loss by active secretion of chloride into the intestinal lumen.

3.
Dig Dis Sci ; 63(2): 356-365, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29218485

RESUMO

OBJECTIVES: Microvillus inclusion disease (MVID) is a severe form of neonatal diarrhea, caused mainly by mutations in MYO5B. Inactivating mutations in MYO5B causes depolarization of enterocytes in the small intestine, which gives rise to chronic, unremitting secretory diarrhea. While the pathology of the small intestine in MVID patients is well described, little is known about extraintestinal effects of MYO5B mutation. METHODS: We examined stomach, liver, pancreas, colon, and kidney in Navajo MVID patients, who share a single homozygous MYO5B-P660L (1979C>T p.Pro660Leu, exon 16). Sections were stained for markers of the apical membrane to assess polarized trafficking. RESULTS: Navajo MVID patients showed notable changes in H/K-ATPase-containing tubulovesicle structure in the stomach parietal cells. Colonic mucosa was morphologically normal, but did show losses in apical ezrin and Syntaxin 3. Hepatocytes in the MVID patients displayed aberrant canalicular expression of the essential transporters MRP2 and BSEP. The pancreas showed small fragmented islets and a decrease in apical ezrin in pancreatic ducts. Kidney showed normal primary cilia. CONCLUSIONS: These findings indicate that the effects of the P660L mutation in MYO5B in Navajo MVID patients are not limited to the small intestine, but that certain tissues may be able to compensate functionally for alterations in apical trafficking.


Assuntos
Membrana Celular/fisiologia , Síndromes de Malabsorção/metabolismo , Microvilosidades/patologia , Mucolipidoses/metabolismo , Criança , Feminino , Predisposição Genética para Doença , Humanos , Índios Norte-Americanos , Lactente , Recém-Nascido , Rim , Síndromes de Malabsorção/genética , Masculino , Microvilosidades/genética , Microvilosidades/metabolismo , Mucolipidoses/genética , Mutação , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Miosina Tipo V/genética , Miosina Tipo V/metabolismo , Pâncreas , Estômago
4.
Am J Physiol Gastrointest Liver Physiol ; 312(1): G67-G76, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27881402

RESUMO

The plasticity of gastric chief cells is exemplified by their ability to transdifferentiate into spasmolytic polypeptide-expressing metaplasia (SPEM) after parietal cell loss. We sought to determine if chief cell maturity is a limiting factor in the capacity to transdifferentiate. Mist1-/- mice, previously shown to form only immature chief cells, were treated with DMP-777 or L635 to study the capability of these immature chief cells to transdifferentiate into a proliferative metaplastic lineage after acute parietal cell loss. Mist1-/- mice treated with DMP-777 showed fewer chief cell to SPEM transitions. Mist1-/- mice treated with L635 demonstrated significantly fewer proliferative SPEM cells compared with control mice. Thus immature chief cells were unable to transdifferentiate efficiently into SPEM after acute parietal cell loss. To determine whether chief cell age affects transdifferentiation into SPEM, we used tamoxifen to induce YFP expression in chief cells of Mist1CreER/+;RosaYFP mice and subsequently treated the cells with L635 to induce SPEM at 1 to 3.5 mo after tamoxifen treatment. After L635 treatment to induce acute parietal cell loss, 43% of all YFP-positive cells at 1 mo posttamoxifen were SPEM cells, of which 44% of these YFP-positive SPEM cells were proliferative. By 2 mo after tamoxifen induction, only 24% of marked SPEM cells were proliferating. However, by 3.5 mo after tamoxifen induction, only 12% of marked chief cells transdifferentiated into SPEM and none were proliferative. Thus, as chief cells age, they lose their ability to transdifferentiate into SPEM and proliferate. Therefore, both functional maturation and age limit chief cell plasticity. NEW & NOTEWORTHY: Previous investigations have indicated that spasmolytic polypeptide-expressing metaplasia (SPEM) in the stomach arises from transdifferentiation of chief cells. Nevertheless, the intrinsic properties of chief cells that influence transdifferentiation have been largely unknown. We now report that the ability to transdifferentiate into SPEM is impaired in chief cells that lack full functional maturation, and as chief cells age, they lose their ability to transdifferentiate. Thus chief cell plasticity is dependent on both cell age and maturation.


Assuntos
Linhagem da Célula/fisiologia , Transdiferenciação Celular/fisiologia , Celulas Principais Gástricas/patologia , Estômago/patologia , Fatores Etários , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proliferação de Células/fisiologia , Celulas Principais Gástricas/metabolismo , Mucosa Gástrica/metabolismo , Metaplasia/metabolismo , Metaplasia/patologia , Camundongos , Camundongos Knockout , Células Parietais Gástricas/metabolismo , Células Parietais Gástricas/patologia , Peptídeos/metabolismo
5.
Cell Mol Gastroenterol Hepatol ; 2(2): 131-157, 2016 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-27019864

RESUMO

BACKGROUND AND AIMS: Inactivating mutations in MYO5B cause severe neonatal diarrhea in Microvillus Inclusion Disease. Loss of active MYO5B causes the formation of pathognomonic inclusions and aberrations in brush border enzymes. METHODS: We developed three mouse models of germline, constitutively intestinal targeted and inducible intestinal targeted deletion of MYO5B. The mice were evaluated for enterocyte cellular morphology. RESULTS: Germline MYO5B KO mice showed early diarrhea and failure to thrive with evident microvillus inclusions and loss of apical transporters in the duodenum. IgG was present within inclusions. Apical transporters were lost and inclusions were present in the duodenum, but were nearly absent in the ileum. VillinCre;MYO5BF/F mice showed similar pathology and morphological changes in duodenal enterocytes. In contrast, when MYO5B KO was induced with tamoxifen treatment at 8 weeks of age, VillinCreERT2;MYO5BF/F mice developed severe diarrhea with loss of duodenal brush border enzymes, but few inclusions were observed in enterocytes. However, if tamoxifen is administered to 2-day-old VillinCreERT2;MYO5BF/F mice, prominent microvillus inclusions were observed. CONCLUSIONS: The microvillus inclusions that develop after MYO5B loss reveal the presence of an unrecognized apical membrane trafficking pathway in neonatal duodenal enterocytes. However, the diarrheal pathology after MYO5B loss is due to deficits in transporter presentation at the apical membrane in duodenal enterocytes.

6.
Am J Pathol ; 185(8): 2219-31, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26073039

RESUMO

Doublecortin-like kinase 1 (Dclk1) is considered a reliable marker for tuft cells in the gastrointestinal tract. We investigated the dynamic changes of tuft cells associated with mouse models of oxyntic atrophy and metaplasia in the stomach. Increases in the numbers of Dclk1-positive tuft cells were observed in several models of parietal cell loss. However, the expanded population of Dclk1-expressing cells showed a morphologically distinct structure in apical microvilli and acetylated microtubules, which was not seen in the tuft cells present in the normal gastric mucosa. These microvillar sensory cells (MVSCs) showed no evidence of proliferation. The expansion of the MVSCs induced by oxyntic atrophy was reversible after the return of parietal cells. More important, expansion of MVSCs after induced parietal cell loss was not observed in Gast(-/-) mice. Although the Dclk1-expressing cells in the normal gastric mucosa were in part derived from Lrig1-expressing stem cells, the Lrig1-lineaged cells did not produce the expanded Dclk1-expressing cells associated with oxyntic atrophy. These studies indicate that loss of parietal cells leads to the reversible emergence of a novel Dclk1-expressing sensory cell population in the gastric mucosa.


Assuntos
Mucosa Gástrica/metabolismo , Gastrinas/metabolismo , Células Parietais Gástricas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Atrofia/metabolismo , Atrofia/patologia , Mucosa Gástrica/patologia , Metaplasia , Camundongos , Células Parietais Gástricas/patologia , Proteínas Serina-Treonina Quinases/genética , Estômago/patologia
7.
J Cell Sci ; 128(8): 1617-26, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25673875

RESUMO

Rab11a is a key component of the apical recycling endosome that aids in the trafficking of proteins to the luminal surface in polarized epithelial cells. Utilizing conditional Rab11a-knockout specific to intestinal epithelial cells, and human colonic epithelial CaCo2-BBE cells with stable Rab11a knockdown, we examined the molecular and pathological impact of Rab11a deficiency on the establishment of apical cell polarity and microvillus morphogenesis. We demonstrate that loss of Rab11a induced alterations in enterocyte polarity, shortened microvillar length and affected the formation of microvilli along the lateral membranes. Rab11a deficiency in enterocytes altered the apical localization of syntaxin 3. These data affirm the role of Rab11a in apical membrane trafficking and the maintenance of apical microvilli in enterocytes.


Assuntos
Enterócitos/ultraestrutura , Microvilosidades/metabolismo , Proteínas Qa-SNARE/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Células CACO-2 , Polaridade Celular , Endossomos/metabolismo , Células HEK293 , Humanos , Camundongos , Camundongos Knockout , Transporte Proteico
8.
Am J Physiol Gastrointest Liver Physiol ; 307(8): G777-92, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25190476

RESUMO

Oxyntic atrophy in the stomach leads to chief cell transdifferentiation into spasmolytic polypeptide expressing metaplasia (SPEM). Investigations of preneoplastic metaplasias in the stomach are limited by the sole reliance on in vivo mouse models, owing to the lack of in vitro models for distinct normal mucosal lineages and metaplasias. Utilizing the Immortomouse, in vitro cell models of chief cells and SPEM were developed to study the characteristics of normal chief cells and metaplasia. Chief cells and SPEM cells isolated from Immortomice were cultured and characterized at both the permissive (33°C) and the nonpermissive temperature (39°C). Clones were selected on the basis of their transcriptional expression of specific stomach lineage markers (named ImChief and ImSPEM) and protein expression and growth were analyzed. The transcriptional expression profiles of ImChief and ImSPEM cells were compared further by using gene microarrays. ImChief cells transcriptionally express most chief cell markers and contain pepsinogen C and RAB3D-immunostaining vesicles. ImSPEM cells express the SPEM markers TFF2 and HE4 and constitutively secrete HE4. Whereas ImChief cells cease proliferation at the nonpermissive temperature, ImSPEM cells continue to proliferate at 39°C. Gene expression profiling of ImChief and ImSPEM revealed myelin and lymphocyte protein 2 (MAL2) as a novel marker of SPEM lineages. Our results indicate that the expression and proliferation profiles of the novel ImChief and ImSPEM cell lines resemble in vivo chief and SPEM cell lineages. These cell culture lines provide the first in vitro systems for studying the molecular mechanisms of the metaplastic transition in the stomach.


Assuntos
Celulas Principais Gástricas/metabolismo , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina/metabolismo , Peptídeos/metabolismo , Estômago/patologia , Animais , Biomarcadores/metabolismo , Células Cultivadas , Mucosa Gástrica/metabolismo , Metaplasia/diagnóstico , Camundongos , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Pepsinogênio C/genética , Pepsinogênio C/metabolismo , Peptídeos/genética , Proteínas/genética , Proteínas/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteínas rab3 de Ligação ao GTP/genética , Proteínas rab3 de Ligação ao GTP/metabolismo
9.
Gastroenterology ; 146(7): 1727-38.e8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24534633

RESUMO

BACKGROUND & AIMS: Loss of parietal cells causes the development of spasmolytic polypeptide-expressing metaplasia (SPEM) through transdifferentiation of chief cells. In the presence of inflammation, SPEM can advance into a more proliferative metaplasia with increased expression of intestine-specific transcripts. We used L635 to induce acute SPEM with inflammation in mice and investigated the roles of inflammatory cells in the development of SPEM. METHODS: To study the adaptive immune system, Rag1 knockout, interferon-γ-deficient, and wild-type (control) mice received L635 for 3 days. To study the innate immune system, macrophages were depleted by intraperitoneal injection of clodronate liposomes 2 days before and throughout L635 administration. Neutrophils were depleted by intraperitoneal injection of an antibody against Ly6G 2 days before and throughout L635 administration. Pathology and immunohistochemical analyses were used to determine depletion efficiency, metaplasia, and proliferation. To characterize SPEM in each model, gastric tissues were collected and levels of Cftr, Dmbt1, and Gpx2 mRNAs were measured. Markers of macrophage polarization were used to identify subpopulations of macrophages recruited to the gastric mucosa. RESULTS: Administration of L635 to Rag1 knockout, interferon-γ-deficient, and neutrophil-depleted mice led to development of proliferative SPEM and up-regulation of intestine-specific transcripts in SPEM cells, similar to controls. However, macrophage-depleted mice given L635 showed significant reductions in numbers of SPEM cells, SPEM cell proliferation, and expression of intestine-specific transcripts, compared with control mice given L635. In mice given L635, as well as patients with intestinal metaplasia, M2 macrophages were the primary inflammatory component. CONCLUSIONS: Results from studies of mouse models and human metaplastic tissues indicate that M2 macrophages promote the advancement of SPEM in the presence of inflammation.


Assuntos
Transformação Celular Neoplásica/metabolismo , Gastrite/metabolismo , Macrófagos/metabolismo , Células Parietais Gástricas/metabolismo , Peptídeos/metabolismo , Neoplasias Gástricas/metabolismo , Imunidade Adaptativa , Animais , Atrofia , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/imunologia , Transformação Celular Neoplásica/patologia , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Modelos Animais de Doenças , Gastrite/induzido quimicamente , Gastrite/genética , Gastrite/imunologia , Gastrite/patologia , Regulação Neoplásica da Expressão Gênica , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Imunidade Inata , Mediadores da Inflamação/metabolismo , Interferon gama/deficiência , Interferon gama/genética , Macrófagos/imunologia , Masculino , Metaplasia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucinas/genética , Mucinas/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Células Parietais Gástricas/imunologia , Células Parietais Gástricas/patologia , Fenótipo , RNA Mensageiro/metabolismo , Neoplasias Gástricas/genética , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/patologia , Regulação para Cima
10.
Physiol Genomics ; 45(15): 667-83, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23715263

RESUMO

In a screen for genes expressed specifically in gastric mucous neck cells, we identified GKN3, the recently discovered third member of the gastrokine family. We present confirmatory mouse data and novel porcine data showing that mouse GKN3 expression is confined to mucous cells of the corpus neck and antrum base and is prominently expressed in metaplastic lesions. GKN3 was proposed originally to be expressed in some human populations and a pseudogene in others. To investigate that hypothesis, we studied human GKN3 evolution in the context of its paralogous genomic neighbors, GKN1 and GKN2. Haplotype analysis revealed that GKN3 mimics GKN2 in patterns of exonic SNP allocation, whereas GKN1 appeared to be more stringently selected. GKN3 showed signatures of both directional selection and population based selective sweeps in humans. One such selective sweep includes SNP rs10187256, originally identified as an ancestral tryptophan to premature STOP codon mutation. The derived (nonancestral) allele went to fixation in Asia. We show that another SNP, rs75578132, identified 5 bp downstream of rs10187256, exhibits a second selective sweep in almost all Europeans, some Latinos, and some Africans, possibly resulting from a reintroduction of European genes during African colonization. Finally, we identify a mutation that would destroy the splice donor site in the putative exon3-intron3 boundary, which occurs in all human genomes examined to date. Our results highlight a stomach-specific human genetic locus, which has undergone various selective sweeps across European, Asian, and African populations and thus reflects geographic and ethnic patterns in genome evolution.


Assuntos
Proteínas de Transporte/genética , Grupos de Populações Continentais/genética , Evolução Molecular , Loci Gênicos/genética , Proteínas de Membrana/genética , Pseudogenes/genética , Seleção Genética/genética , Animais , Proteínas de Transporte/metabolismo , Biologia Computacional , Primers do DNA/genética , Imunofluorescência , Mucosa Gástrica/metabolismo , Genética Populacional , Genótipo , Haplótipos/genética , Humanos , Funções Verossimilhança , Macaca mulatta/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL/genética , Análise em Microsséries , Microscopia Confocal , Modelos Genéticos , Mutação/genética , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Especificidade da Espécie , Sus scrofa/genética
11.
Gut ; 62(9): 1270-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22773549

RESUMO

OBJECTIVES: Spasmolytic polypeptide-expressing metaplasia (SPEM) develops as a preneoplastic lesion in the stomachs of mice and humans after parietal cell loss. To identify the commonalities and differences between phenotypic SPEM lineages, SPEM were studied from three different mouse models of parietal cell loss: with chronic inflammation with Helicobacter felis infection; with acute inflammation with L635 treatment; and without inflammation following DMP-777 treatment. DESIGN: RNA transcripts from laser capture microdissected normal chief cells and SPEM lineages were compared using gene microarray. Alterations in transcripts were validated by quantitative real-time PCR. Clusterin and cystic fibrosis transmembrane conductance regulator (CFTR) were selected for immunohistochemical analysis in all mouse models as well as in human SPEM, intestinal metaplasia and gastric cancer. RESULTS: Transcript expression patterns demonstrated differences among the phenotypic SPEM models. Clusterin expression was significantly upregulated in all three mouse SPEM models as well as in human SPEM. The highest clusterin expression in human gastric cancers correlated with poor survival. Conversely, CFTR expression was upregulated only in SPEM with inflammation in mice. In humans, intestinal metaplasia, but not SPEM, expressed CFTR. CONCLUSIONS: While markers such as clusterin are expressed in all phenotypic SPEM lineages, distinct patterns of upregulated genes including CFTR are present in murine metaplasia associated with inflammation, indicative of progression of metaplasia towards a more intestinalised metaplastic phenotype.


Assuntos
Clusterina/metabolismo , Infecções por Helicobacter/complicações , Inflamação , Intestinos/patologia , Células Parietais Gástricas/patologia , Peptídeos , Animais , Azetidinas/farmacologia , Biomarcadores/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Inflamação/tratamento farmacológico , Inflamação/etiologia , Inflamação/genética , Inflamação/metabolismo , Microdissecção e Captura a Laser , Metaplasia/diagnóstico , Metaplasia/etiologia , Metaplasia/genética , Metaplasia/metabolismo , Camundongos , Camundongos Endogâmicos CFTR , Células Parietais Gástricas/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Piperazinas/farmacologia , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/metabolismo , Regulação para Cima
12.
Gastroenterology ; 139(6): 2028-2037.e9, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20854822

RESUMO

BACKGROUND & AIMS: Gastric cancer evolves in the setting of a pathologic mucosal milieu characterized by both loss of acid-secreting parietal cells and mucous cell metaplasias. Indeed, mucous cell metaplasia is considered the critical preneoplastic lesion for gastric cancer. Previous investigations have shown that infection of mice with Helicobacter felis or induction of acute parietal cell loss with the drug DMP-777 leads to the emergence of a type of metaplasia designated spasmolytic polypeptide-expressing metaplasia (SPEM). We have hypothesized that SPEM arises from proliferating cells in gland bases, either from a cryptic progenitor cell or by transdifferentiation of mature chief cells. METHODS: Taking advantage of the chief cell-restricted expression of Mist1-Cre-ER(T2), we used lineage mapping to examine whether SPEM lineages were derived from chief cells in 3 independent models of induction by DMP-777 treatment, L-635 treatment, or H felis infection. RESULTS: Treatment of mice with L-635 for 3 days led to rapid parietal cell loss, induction of a prominent inflammatory infiltrate, and emergence of SPEM. In all 3 models, SPEM developed, at least in part, from transdifferentiation of chief cells. We further found that acute parietal cell loss in the setting of inflammation (L-635 treatment) led to more rapid induction and expansion of SPEM derived from transdifferentiation of chief cells. CONCLUSIONS: These studies provide direct evidence by lineage tracing that SPEM evolves from differentiated chief cells. Thus, mature gastric chief cells have the ability to act as cryptic progenitors and reacquire proliferative capacity within the context of mucosal injury and inflammation.


Assuntos
Celulas Principais Gástricas/patologia , Gastrite/patologia , Lesões Pré-Cancerosas/patologia , Células-Tronco/patologia , Neoplasias Gástricas/patologia , Doença Aguda , Animais , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Linhagem da Célula/fisiologia , Celulas Principais Gástricas/fisiologia , Doença Crônica , Modelos Animais de Doenças , Gastrite/microbiologia , Gastrite/fisiopatologia , Infecções por Helicobacter/patologia , Infecções por Helicobacter/fisiopatologia , Helicobacter felis , Óperon Lac/genética , Metaplasia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Parietais Gástricas/patologia , Células Parietais Gástricas/fisiologia , Peptídeos/genética , Peptídeos/metabolismo , Lesões Pré-Cancerosas/microbiologia , Lesões Pré-Cancerosas/fisiopatologia , Células-Tronco/fisiologia , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/fisiopatologia
13.
Dev Biol ; 325(1): 211-24, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19013146

RESUMO

In the mammalian gastrointestinal tract, the cell fate decisions that specify the development of multiple, diverse lineages are governed in large part by interactions of stem and early lineage progenitor cells with their microenvironment, or niche. Here, we show that the gastric parietal cell (PC) is a key cellular component of the previously undescribed niche for the gastric epithelial neck cell, the progenitor of the digestive enzyme secreting zymogenic (chief) cell (ZC). Genetic ablation of PCs led to failed patterning of the entire zymogenic lineage: progenitors showed premature expression of differentiated cell markers, and fully differentiated ZCs failed to develop. We developed a separate mouse model in which PCs localized not only to the progenitor niche, but also ectopically to the gastric unit base, which is normally occupied by terminally differentiated ZCs. Surprisingly, these mislocalized PCs did not maintain adjacent zymogenic lineage cells in the progenitor state, demonstrating that PCs, though necessary, are not sufficient to define the progenitor niche. We induced this PC mislocalization by knocking out the cytoskeleton-regulating gene Cd2ap in Mist1(-/-) mice, which led to aberrant E-cadherin localization in ZCs, irregular ZC-ZC junctions, and disruption of the ZC monolayer by PCs. Thus, the characteristic histology of the gastric unit, with PCs in the middle and ZCs in the base, may depend on establishment of an ordered adherens junction network in ZCs as they migrate into the base.


Assuntos
Diferenciação Celular , Linhagem da Célula , Celulas Principais Gástricas/citologia , Células Epiteliais/citologia , Nicho de Células-Tronco/citologia , Células-Tronco/citologia , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/deficiência , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Caderinas/metabolismo , Polaridade Celular , Proliferação de Células , Celulas Principais Gástricas/metabolismo , Celulas Principais Gástricas/ultraestrutura , Proteínas do Citoesqueleto/deficiência , Proteínas do Citoesqueleto/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/ultraestrutura , Junções Intercelulares/metabolismo , Junções Intercelulares/ultraestrutura , Camundongos , Modelos Biológicos , Células Parietais Gástricas/citologia , Células Parietais Gástricas/metabolismo , Células Parietais Gástricas/ultraestrutura , Ligação Proteica , Transporte Proteico , Nicho de Células-Tronco/metabolismo , Nicho de Células-Tronco/ultraestrutura , Células-Tronco/metabolismo , Células-Tronco/ultraestrutura
14.
Gastric Cancer ; 12(4): 189-97, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20047123

RESUMO

Gastric cancer is the second leading cause of cancer-related death worldwide, but the details of gastric carcinogenesis remain unclear. In humans, two preneoplastic metaplasias are associated with the precancerous stomach: intestinal metaplasia and spasmolytic polypeptide-expressing metaplasia (SPEM). While mouse models of Helicobacter sp. infection have not shown intestinal metaplasia, a number of mouse models lead to the evolution of SPEM. In this review, we summarize increasing data that indicates that SPEM arises in the setting of parietal cell loss, either following acute druginduced oxyntic atrophy or in chronic oxyntic atrophy associated with H. felis infection. Importantly, recent investigations support the origin of SPEM through transdifferentiation from mature chief cells following parietal cell loss. Novel biomarkers of SPEM, such as HE4, hold promise as specific markers of the metaplastic process distinct from normal gastric lineages. Staining with HE4 in humans and other studies in gerbils suggest that SPEM arises initially in the human stomach following parietal cell loss and then further evolves into intestinal metaplasia, likely in association with chronic inflammation. Further studies are needed to broaden our knowledge of metaplasia and early cancer-specific biomarkers that could give insights into both lineage derivation and preneoplasia detection.


Assuntos
Células Parietais Gástricas/metabolismo , Peptídeos/metabolismo , Neoplasias Gástricas/etiologia , Animais , Transformação Celular Neoplásica , Modelos Animais de Doenças , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Gerbillinae , Humanos , Metaplasia/metabolismo , Metaplasia/patologia , Camundongos , Lesões Pré-Cancerosas , Neoplasias Gástricas/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA