RESUMO
Exocrine-to-endocrine cross talk in the pancreas is crucial to maintain ß-cell function. However, the molecular mechanisms underlying this cross talk are largely undefined. Trefoil factor 2 (Tff2) is a secreted factor known to promote the proliferation of ß-cells in vitro, but its physiological role in vivo in the pancreas is unknown. Also, it remains unclear which pancreatic cell type expresses Tff2 protein. We therefore created a mouse model with a conditional knockout of Tff2 in the murine pancreas. We find that the Tff2 protein is preferentially expressed in acinar but not ductal or endocrine cells. Tff2 deficiency in the pancreas reduces ß-cell mass on embryonic day 16.5. However, homozygous mutant mice are born without a reduction of ß-cells and with acinar Tff3 compensation by day 7. When mice are aged to 1 year, both male and female homozygous and male heterozygous mutants develop impaired glucose tolerance without affected insulin sensitivity. Perifusion analysis reveals that the second phase of glucose-stimulated insulin secretion from islets is reduced in aged homozygous mutant compared with controls. Collectively, these results demonstrate a previously unknown role of Tff2 as an exocrine acinar cell-derived protein required for maintaining functional endocrine ß-cells in mice.
Assuntos
Células Acinares , Envelhecimento , Células Secretoras de Insulina , Camundongos Knockout , Fator Trefoil-2 , Animais , Células Secretoras de Insulina/metabolismo , Camundongos , Fator Trefoil-2/metabolismo , Fator Trefoil-2/genética , Masculino , Células Acinares/metabolismo , Feminino , Envelhecimento/metabolismo , Envelhecimento/fisiologia , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/citologia , Secreção de Insulina/fisiologia , Secreção de Insulina/genética , Fatores Trefoil/metabolismo , Fatores Trefoil/genética , Peptídeos/metabolismoRESUMO
Ductal progenitor-like cells are a sub-population of ductal cells in the adult human pancreas that have the potential to contribute to regenerative medicine. However, the microenvironmental cues that regulate their activation are poorly understood. Here, we establish a 3-dimensional suspension culture system containing six defined soluble factors in which primary human ductal progenitor-like and ductal non-progenitor cells survive but do not proliferate. Expansion and polarization occur when suspension cells are provided with a low concentration (5% v/v) of Matrigel, a sarcoma cell product enriched in many extracellular matrix (ECM) proteins. Screening of ECM proteins identified that collagen IV can partially recapitulate the effects of Matrigel. Inhibition of integrin α1ß1, a major collagen IV receptor, negates collagen IV- and Matrigel-stimulated effects. These results demonstrate that collagen IV is a key ECM protein that stimulates the expansion and polarization of human ductal progenitor-like and ductal non-progenitor cells via integrin α1ß1 receptor signaling.
RESUMO
Pancreatic ductal progenitor cells have been proposed to contribute to adult tissue maintenance and regeneration after injury, but the identity of such ductal cells remains elusive. Here, from adult mice, we identify a near homogenous population of ductal progenitor-like clusters, with an average of 8 cells per cluster. They are a rare subpopulation, about 0.1% of the total pancreatic cells, and can be sorted using a fluorescence-activated cell sorter with the CD133highCD71lowFSCmid-high phenotype. They exhibit properties in self-renewal and tri-lineage differentiation (including endocrine-like cells) in a unique 3-dimensional colony assay system. An in vitro lineage tracing experiment, using a novel HprtDsRed/+ mouse model, demonstrates that a single cell from a cluster clonally gives rise to a colony. Droplet RNAseq analysis demonstrates that these ductal clusters express embryonic multipotent progenitor cell markers Sox9, Pdx1, and Nkx6-1, and genes involved in actin cytoskeleton regulation, inflammation responses, organ development, and cancer. Surprisingly, these ductal clusters resist prolonged trypsin digestion in vitro, preferentially survive in vivo after a severe acinar cell injury and become proliferative within 14 days post-injury. Thus, the ductal clusters are the fundamental units of progenitor-like cells in the adult murine pancreas with implications in diabetes treatment and tumorigenicity.
Assuntos
Células Acinares , Ductos Pancreáticos , Camundongos , Animais , Pâncreas , Células-Tronco , Diferenciação CelularRESUMO
Thrombospondin-1 (TSP1) is a secreted protein minimally expressed in health but increased in disease and age. TSP1 binds to the cell membrane receptor CD47, which itself engages signal regulatory protein α (SIRPα), and the latter creates a checkpoint for immune activation. Individuals with cancer administered checkpoint-blocking molecules developed insulin-dependent diabetes. Relevant to this, CD47 blocking antibodies and SIRPα fusion proteins are in clinical trials. We characterized the molecular signature of TSP1, CD47, and SIRPα in human islets and pancreata. Fresh islets and pancreatic tissue from nondiabetic individuals were obtained. The expression of THBS1, CD47, and SIRPA was determined using single-cell mRNA sequencing, immunofluorescence microscopy, Western blot, and flow cytometry. Islets were exposed to diabetes-affiliated inflammatory cytokines and changes in protein expression were determined. CD47 mRNA was expressed in all islet cell types. THBS1 mRNA was restricted primarily to endothelial and mesenchymal cells, whereas SIRPA mRNA was found mostly in macrophages. Immunofluorescence staining showed CD47 protein expressed by ß cells and present in the exocrine pancreas. TSP1 and SIRPα proteins were not seen in islets or the exocrine pancreas. Western blot and flow cytometry confirmed immunofluorescent expression patterns. Importantly, human islets produced substantial quantities of secreted TSP1. Human pancreatic exocrine and endocrine tissue expressed CD47, whereas fresh islets displayed cell surface CD47 and secreted TSP1 at baseline and in inflammation. These findings suggest unexpected effects on islets from agents that intersect TSP1-CD47-SIRPα.NEW & NOTEWORTHY CD47 is a cell surface receptor with two primary ligands, soluble thrombospondin-1 (TSP1) and cell surface signal regulatory protein alpha (SIRPα). Both interactions provide checkpoints for immune cell activity. We determined that fresh human islets display CD47 and secrete TSP1. However, human islet endocrine cells lack SIRPα. These gene signatures are likely important given the increasing use of CD47 and SIRPα blocking molecules in individuals with cancer.
Assuntos
Antígeno CD47 , Neoplasias , Humanos , Antígeno CD47/genética , Antígeno CD47/metabolismo , Macrófagos/metabolismo , Neoplasias/metabolismo , Receptores de Superfície Celular/metabolismo , Trombospondinas/metabolismo , Trombospondinas/uso terapêutico , Trombospondina 1/genética , Trombospondina 1/metabolismoRESUMO
PURPOSE OF REVIEW: Type 1 diabetes (T1D) results from the loss of immune tolerance to pancreatic beta-cells leading to their destruction. Immune intervention therapies tested in T1D so far delayed progression but failed to restore tolerance, which partly explains their lack of durable clinical efficacy. RECENT FINDINGS: The role of beta-cells and islets themselves in dialogue with their micro- and macro-environment including the immune system and the intestinal microbiome is increasingly evident. Indeed, islets can both maintain and break immune tolerance. Some recent immune therapies in cancer that block immune regulation also break tolerance. Induction of immune tolerance requires activating immune activation too, whereas immune suppression precludes this process. Immunotherapy alone my not suffice without engaging islets to restore tolerance and preserve beta-cell function. SUMMARY: New insight into the role of islet tissue and its interaction with its environment in preserving or breaking tolerance has contributed to understand the development of islet autoimmunity and T1D. Knowing which factors in islets and the immune system contribute to maintaining, breaking, and restoring the balance in the immune system is critical to prevent initiation and reverse disease progression, and guides the design of novel tolerogenic strategies for durable therapeutic intervention and remission that target both the immune system and distressed islets.
Assuntos
Diabetes Mellitus Tipo 1 , Tolerância Imunológica , Células Secretoras de Insulina , Autoimunidade/efeitos dos fármacos , Autoimunidade/imunologia , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/imunologia , Microbioma Gastrointestinal/imunologia , Humanos , Tolerância Imunológica/efeitos dos fármacos , Tolerância Imunológica/imunologia , Imunoterapia/métodos , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/imunologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/imunologiaRESUMO
Gaucher disease is a lipid storage disorder due to deficiency of beta glucocerebrosidase. It's an autosomal recessive disease and as a result of this enzyme deficiency, glucocerebroside accumulates in various types of tissues like liver, brain spleen and bone marrow. We aimed to describe the effects of enzyme replacement therapy in three members of a family with Gaucher disease and to emphasize screening of the family members of the patients with Gaucher disease. Furthermore, late diagnosis and treatment in these patients have a minimal effect on improvement of the quality of life, and early diagnosis and treatment are very important in Gaucher disease.
Assuntos
Terapia de Reposição de Enzimas , Doença de Gaucher/tratamento farmacológico , Glucosilceramidase/uso terapêutico , Adolescente , Análise Mutacional de DNA , Doença de Gaucher/complicações , Doença de Gaucher/genética , Glucosilceramidase/deficiência , Hemoglobinas/análise , Humanos , Masculino , Pessoa de Meia-Idade , Esplenomegalia/etiologiaAssuntos
Medula Óssea/imunologia , Imunoglobulina M/química , Macroglobulinemia de Waldenstrom/patologia , Exame de Medula Óssea , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Cristalização , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Macroglobulinemia de Waldenstrom/imunologiaRESUMO
Since similar symptoms and findings can be seen in the deficiencies of both iron and zinc, we aimed to evaluate the serum zinc levels of women with iron deficiency anemia (IDA). This study was conducted with women with iron deficiency and a healthy control group. When serum zinc levels were compared, they were found to be lower in the IDA group, which was statistically significant. With the help of these studies, iron and zinc treatment instead of only iron replacement may be considered in cases of iron deficiency.