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Unlike sessile macrophages that occupy specialized tissue niches, non-classical monocytes (NCMs)-circulating phagocytes that patrol and cleanse the luminal surface of the vascular tree-are characterized by constant movement. Here, we examined the nature of the NCM's nurturing niche. Expression of the growth factor CSF1 on endothelial cells was required for survival of NCMs in the bloodstream. Lack of endothelial-derived CSF1 did not affect blood CSF1 concentration, suggesting that NCMs rely on scavenging CSF1 present on endothelial cells. Deletion of the transmembrane chemokine and adhesion factor CX3CL1 on endothelial cells impaired NCM survival. Mechanistically, endothelial-derived CX3CL1 and integrin subunit alpha L (ITGAL) facilitated the uptake of CSF1 by NCMs. CSF1 was produced by all tissular endothelial cells, and deletion of Csf1 in all endothelial cells except bone marrow sinusoids impaired NCM survival, arguing for a model where the full vascular tree acts as a niche for NCMs and where survival and patrolling function are connected.
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Amino acid substitutions in the kinase domain of the human CSF1R gene are associated with autosomal dominant adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). To model the human disease, we created a disease-associated mutation (pGlu631Lys; E631K) in the mouse Csf1r locus. Homozygous mutation (Csf1rE631K/E631K) phenocopied the Csf1r knockout, with prenatal mortality or severe postnatal growth retardation and hydrocephalus. Heterozygous mutation delayed the postnatal expansion of tissue macrophage populations in most organs. Bone marrow cells from Csf1rE631K/+mice were resistant to CSF1 stimulation in vitro, and Csf1rE631K/+ mice were unresponsive to administration of a CSF1-Fc fusion protein, which expanded tissue macrophage populations in controls. In the brain, microglial cell numbers and dendritic arborisation were reduced in Csf1rE631K/+ mice, as in patients with ALSP. The microglial phenotype is the opposite of microgliosis observed in Csf1r+/- mice. However, we found no evidence of brain pathology or impacts on motor function in aged Csf1rE631K/+ mice. We conclude that heterozygous disease-associated CSF1R mutations compromise CSF1R signalling. We speculate that leukoencephalopathy associated with dominant human CSF1R mutations requires an environmental trigger and/or epistatic interaction with common neurodegenerative disease-associated alleles.
Assuntos
Leucoencefalopatias , Doenças Neurodegenerativas , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos , Animais , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/patologia , Camundongos , Mutação/genética , Doenças Neurodegenerativas/patologia , Neuroglia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genéticaRESUMO
Macrophages regulate metabolic homeostasis in health and disease. Macrophage colony-stimulating factor (CSF1)-dependent macrophages contribute to homeostatic control of the size of the liver. This study aimed to determine the systemic metabolic consequences of elevating circulating CSF1. Acute administration of a CSF1-Fc fusion protein to mice led to monocytosis, increased resident tissue macrophages in the liver and all major organs, and liver growth. These effects were associated with increased hepatic glucose uptake and extensive mobilization of body fat. The impacts of CSF1 on macrophage abundance, liver size, and body composition were rapidly reversed to restore homeostasis. The effects of CSF1 on metabolism were independent of several known endocrine regulators and did not impact the physiological fasting response. Analysis using implantable telemetry in metabolic cages revealed progressively reduced body temperature and physical activity with no change in diurnal food intake. These results demonstrate the existence of a dynamic equilibrium between CSF1, the mononuclear phagocyte system, and control of liver-to-body weight ratio, which in turn controls systemic metabolic homeostasis. This novel macrophage regulatory axis has the potential to promote fat mobilization, without changes in appetence, which may have novel implications for managing metabolic syndrome.NEW & NOTEWORTHY CSF1 administration expands tissue macrophages, which transforms systemic metabolism. CSF1 drives fat mobilization and glucose uptake to support liver growth. The effects of CSF1 are independent of normal hormonal metabolic regulation. The effects of CSF1 are rapidly reversible, restoring homeostatic body composition. CSF1-dependent macrophages and liver size are coupled in a dynamic equilibrium.
Assuntos
Fator Estimulador de Colônias de Macrófagos , Macrófagos , Animais , Camundongos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Fator Estimulador de Colônias de Macrófagos/metabolismo , Macrófagos/metabolismo , Metabolismo dos Carboidratos , Glucose/metabolismo , LipídeosRESUMO
Homozygous null mutation of the Csf1r gene (Csf1rko) in rats leads to the loss of most tissue macrophage populations and pleiotropic impacts on postnatal growth and organ maturation, leading to early mortality. The phenotype can be reversed by intraperitoneal transfer of WT BM cells (BMT) at weaning. Here, we used a Csf1r-mApple transgenic reporter to track the fate of donor-derived cells. Following BMT into Csf1rko recipients, mApple+ve cells restored IBA1+ tissue macrophage populations in every tissue. However, monocytes, neutrophils, and B cells in the BM, blood, and lymphoid tissues remained of recipient (mApple-ve ) origin. An mApple+ve cell population expanded in the peritoneal cavity and invaded locally in the mesentery, fat pads, omentum, and diaphragm. One week after BMT, distal organs contained foci of mApple+ve , IBA1-ve immature progenitors that appeared to proliferate, migrate, and differentiate locally. We conclude that rat BM contains progenitor cells that are able to restore, replace, and maintain all tissue macrophage populations in a Csf1rko rat directly without contributing to the BM progenitor or blood monocyte populations.
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Medula Óssea , Macrófagos , Ratos , Animais , Monócitos , Receptores Proteína Tirosina Quinases , Células da Medula ÓsseaRESUMO
Homozygous mutation of the Csf1r locus (Csf1rko) in mice, rats and humans leads to multiple postnatal developmental abnormalities. To enable analysis of the mechanisms underlying the phenotypic impacts of Csf1r mutation, we bred a rat Csf1rko allele to the inbred dark agouti (DA) genetic background and to a Csf1r-mApple reporter transgene. The Csf1rko led to almost complete loss of embryonic macrophages and ablation of most adult tissue macrophage populations. We extended previous analysis of the Csf1rko phenotype to early postnatal development to reveal impacts on musculoskeletal development and proliferation and morphogenesis in multiple organs. Expression profiling of 3-week old wild-type (WT) and Csf1rko livers identified 2760 differentially expressed genes associated with the loss of macrophages, severe hypoplasia, delayed hepatocyte maturation, disrupted lipid metabolism and the IGF1/IGF binding protein system. Older Csf1rko rats developed severe hepatic steatosis. Consistent with the developmental delay in the liver Csf1rko rats had greatly-reduced circulating IGF1. Transfer of WT bone marrow (BM) cells at weaning without conditioning repopulated resident macrophages in all organs, including microglia in the brain, and reversed the mutant phenotypes enabling long term survival and fertility. WT BM transfer restored osteoclasts, eliminated osteopetrosis, restored bone marrow cellularity and architecture and reversed granulocytosis and B cell deficiency. Csf1rko rats had an elevated circulating CSF1 concentration which was rapidly reduced to WT levels following BM transfer. However, CD43hi non-classical monocytes, absent in the Csf1rko, were not rescued and bone marrow progenitors remained unresponsive to CSF1. The results demonstrate that the Csf1rko phenotype is autonomous to BM-derived cells and indicate that BM contains a progenitor of tissue macrophages distinct from hematopoietic stem cells. The model provides a unique system in which to define the pathways of development of resident tissue macrophages and their local and systemic roles in growth and organ maturation.
Assuntos
Fígado Gorduroso/genética , Macrófagos/metabolismo , Anormalidades Musculoesqueléticas/genética , Desenvolvimento Musculoesquelético/genética , Osteopetrose/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Animais , Medula Óssea/metabolismo , Medula Óssea/patologia , Transplante de Medula Óssea , Modelos Animais de Doenças , Embrião de Mamíferos , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/terapia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Inativação de Genes , Genes Reporter , Humanos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/deficiência , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Fator de Crescimento Insulin-Like I/deficiência , Fator de Crescimento Insulin-Like I/genética , Metabolismo dos Lipídeos , Fígado/metabolismo , Fígado/patologia , Macrófagos/patologia , Masculino , Anormalidades Musculoesqueléticas/metabolismo , Anormalidades Musculoesqueléticas/patologia , Anormalidades Musculoesqueléticas/terapia , Osteopetrose/metabolismo , Osteopetrose/patologia , Osteopetrose/terapia , Ratos , Ratos Transgênicos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/deficiênciaRESUMO
Fibrillin-1 is a major component of the extracellular microfibrils, where it interacts with other extracellular matrix proteins to provide elasticity to connective tissues, and regulates the bioavailability of TGFß family members. A peptide consisting of the C-terminal 140 amino acids of fibrillin-1 has recently been identified as a glucogenic hormone, secreted from adipose tissue during fasting and targeting the liver to release glucose. This fragment, called asprosin, also signals in the hypothalamus to stimulate appetite. Asprosin levels are correlated with many of the pathologies indicative of metabolic syndrome, including insulin resistance and obesity. Previous studies and reviews have addressed the therapeutic potential of asprosin as a target in obesity, diabetes and related conditions without considering mechanisms underlying the relationship between generation of asprosin and expression of the much larger fibrillin-1 protein. Profibrillin-1 undergoes obligatory cleavage at the cell surface as part of its assembly into microfibrils, producing the asprosin peptide as well as mature fibrillin-1. Patterns of FBN1 mRNA expression are inconsistent with the necessity for regulated release of asprosin. The asprosin peptide may be protected from degradation in adipose tissue. We present evidence for an alternative possibility, that asprosin mRNA is generated independently from an internal promoter within the 3' end of the FBN1 gene, which would allow for regulation independent of fibrillin-synthesis and is more economical of cellular resources. The discovery of asprosin opened exciting possibilities for treatment of metabolic syndrome related conditions, but there is much to be understood before such therapies could be introduced into the clinic.
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Síndrome Metabólica , Humanos , Fibrilina-1/genética , Fibrilina-2 , Fibrilinas , Glucose , Síndrome Metabólica/genética , Proteínas dos Microfilamentos/genética , Obesidade/genética , RNA Mensageiro , Adipocinas/genéticaRESUMO
BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is caused by ectopic fat accumulation in the liver as a consequence of metabolic perturbations associated with obesity, type 2 diabetes, dyslipidemia, and insulin resistance. People with NAFLD may develop metabolic and cardiovascular complications and/or liver-related complications, especially fibrosis and hepatocellular carcinoma, associated with high morbidity and mortality. Due to the high and increasing prevalence of NAFLD, there is an urgent need to identify people at risk of developing liver fibrosis and complications. CC-chemokine ligand 2 (CCL2) is chemokine that attracts inflammatory monocytes to stressed or injured tissues. Infiltrating inflammatory monocytes and CCL2 are strongly implicated in the pathogenesis of liver disease in animal models; however, evidence in patient cohorts is conflicting. METHODS: We investigated associations between circulating CCL2 and clinical parameters, including fibrosis assessed by liver stiffness measurement, in a cohort of 250 NAFLD patients. We also measured fatty acid binding protein 2 (FABP2), a putative biomarker of intestinal permeability in patients with liver disease, since pro-inflammatory gut-derived microbial products may induce inflammatory chemokines such as CCL2. RESULTS: Serum CCL2 levels were weakly associated with liver stiffness, but the association was no longer significant after accounting for age, diabetes, and BMI in a multivariable model. Consistent with this, girth and BMI were the strongest predictors of elevated circulating CCL2. Serum FABP2 was weakly, but significantly, correlated with CCL2, and negatively correlated with estimated glomerular filtration rate. CONCLUSION: Circulating CCL2 and FABP2 are associated with NAFLD comorbidities but not liver disease progression in patients with NAFLD.
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Diabetes Mellitus Tipo 2 , Hepatopatia Gordurosa não Alcoólica , Animais , Humanos , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Adiposidade , Ligantes , Cirrose Hepática/complicações , Quimiocinas/metabolismoRESUMO
The laboratory rat continues to be the model of choice for many studies of physiology, behavior, and complex human diseases. Cells of the mononuclear phagocyte system (MPS; monocytes, macrophages, and dendritic cells) are abundant residents in every tissue in the body and regulate postnatal development, homeostasis, and innate and acquired immunity. Recruitment and proliferation of MPS cells is an essential component of both initiation and resolution of inflammation. The large majority of current knowledge of MPS biology is derived from studies of inbred mice, but advances in technology and resources have eliminated many of the advantages of the mouse as a model. In this article, we review the tools available and the current state of knowledge of development, homeostasis, regulation, and diversity within the MPS of the rat.
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Imunidade Adaptativa , Modelos Animais de Doenças , Imunidade Inata , Sistema Fagocitário Mononuclear/imunologia , Ratos , Animais , Genoma , Homeostase/imunologia , Inflamação/imunologia , Fator Estimulador de Colônias de Macrófagos/genética , Camundongos , Mutação , FenótipoRESUMO
PURPOSE OF REVIEW: The purpose of the review is to summarize the expression and function of CSF1R and its ligands in bone homeostasis and constraints on therapeutic targeting of this axis. RECENT FINDINGS: Bone development and homeostasis depends upon interactions between mesenchymal cells and cells of the mononuclear phagocyte lineage (MPS), macrophages, and osteoclasts (OCL). The homeostatic interaction is mediated in part by the systemic and local production of growth factors, macrophage colony-stimulating factor (CSF1), and interleukin 34 (IL34) that interact with a receptor (CSF1R) expressed exclusively by MPS cells and their progenitors. Loss-of-function mutations in CSF1 or CSF1R lead to loss of OCL and macrophages and dysregulation of postnatal bone development. MPS cells continuously degrade CSF1R ligands via receptor-mediated endocytosis. As a consequence, any local or systemic increase or decrease in macrophage or OCL abundance is rapidly reversible. In principle, both CSF1R agonists and antagonists have potential in bone regenerative medicine but their evaluation in disease models and therapeutic application needs to carefully consider the intrinsic feedback control of MPS biology.
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Doenças Ósseas , Receptor de Fator Estimulador de Colônias de Macrófagos , Humanos , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Macrófagos/metabolismo , Imunoterapia , Homeostase/genética , Doenças Ósseas/tratamento farmacológico , Doenças Ósseas/metabolismoRESUMO
Mutations in the human CSF1R gene have been associated with dominant and recessive forms of neurodegenerative disease. Here we describe the impacts of Csf1r mutation in the rat on development of the brain. Diffusion imaging indicated small reductions in major fiber tracts that may be associated in part with ventricular enlargement. RNA-seq profiling revealed a set of 105 microglial markers depleted in all brain regions of the Csf1rko rats. There was no evidence of region or sex-specific expression of microglia-associated transcripts. Other than the microglial signature, Csf1rko had no effect on any neuronal or region-specific transcript cluster. Expression of markers of oligodendrocytes, astrocytes, dopaminergic neurons and Purkinje cells was minimally affected. However, there were defects in dendritic arborization of doublecortin-positive neurogenic precursors and expression of poly-sialylated neural cell adhesion molecule (PS-NCAM) in the dentate gyrus of the hippocampus. Heterozygous Csf1rko rats had no detectable brain phenotype. We conclude that most brain developmental processes occur normally in the absence of microglia and that CSF1R haploinsufficiency is unlikely to cause leukoencephalopathy.
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Microglia , Doenças Neurodegenerativas/genética , Neurogênese/fisiologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/deficiência , Animais , Modelos Animais de Doenças , Feminino , Técnicas de Inativação de Genes , Humanos , Masculino , Mutação , Ratos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genéticaRESUMO
OBJECTIVE: Thrombospondin-1 (TSP1), a matricellular protein, and Osteocalcin (OCN), a noncollagenous protein secreted by osteoblasts, are known to be up- and down-regulated, respectively, by glucocorticoids. The aim of this study was to determine whether a ratio between TSP1:OCN was altered by changes in glucocorticoid activity in humans. DESIGN: Prospective observational study. SETTING: Tertiary university hospital in Queensland, Australia. PATIENTS AND MEASUREMENTS: Patients with Cushing's syndrome (CS, n = 19), asthma or giant cell arteritis on chronic prednisolone treatment (PRED, n = 13), adrenal insufficiency (AI, n = 16) and healthy volunteers (HV, n = 20). Plasma TSP1 and serum total OCN were measured by immunoassay at 0800h, 1200h and 1600h in patients with CS, patients with AI taking replacement glucocorticoids, HV before and after 4 mg dexamethasone and PRED patients predose at 800 and 4 hours post-dose at 1200 hours. RESULTS: Plasma TSP1 in CS was higher (P < .0001), and serum OCN was lower (P < .0001) than HV. The TSP1:OCN ratio in HV increased significantly after 4 mg dexamethasone (P < .0001) and in AI after taking their hydrocortisone replacement therapy (P < .001). PRED patients had a higher TSP1:OCN ratio compared with HV at both 800 and 1200 hours (both P < .001), but no significant change occurred from pre- to post-dose. A TSP1:OCN ratio of >73 at 800 hours differentiated CS from HV with a sensitivity of 95% and a specificity of 100%. CONCLUSIONS: The TSP1:OCN ratio is elevated in patients on prednisolone and in patients with CS compared with healthy volunteers. It may be a useful biomarker of total body glucocorticoid activity in humans.
Assuntos
Glucocorticoides/uso terapêutico , Osteocalcina/sangue , Trombospondina 1/sangue , Insuficiência Adrenal/sangue , Insuficiência Adrenal/tratamento farmacológico , Adulto , Idoso , Asma/sangue , Asma/tratamento farmacológico , Síndrome de Cushing/sangue , Síndrome de Cushing/tratamento farmacológico , Feminino , Voluntários Saudáveis , Humanos , Hidrocortisona/sangue , Masculino , Pessoa de Meia-Idade , Prednisolona/uso terapêutico , Estudos Prospectivos , Resultado do Tratamento , Adulto JovemRESUMO
Adipose tissue expansion occurs through a combination of hypertrophy of existing adipocytes and generation of new adipocytes via the process of hyperplasia, which involves the proliferation and subsequent differentiation of preadipocytes. Deficiencies in hyperplasia contribute to adipose tissue dysfunction and the association of obesity with chronic cardiometabolic diseases. Thus, increased understanding of hyperplastic pathways may be expected to afford novel therapeutic strategies. We have reported that fibroblast growth factor (FGF)-1 promotes proliferation and differentiation of human preadipocytes and recently demonstrated that bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) is a central, proximal effector. Herein, we describe the identification and characterization of carboxypeptidase X (CPX)-1, a secreted collagen-binding glycoprotein, as a novel downstream effector in human primary and Simpson-Golabi-Behmel syndrome preadipocytes. CPX-1 expression increased after treatment of preadipocytes with FGF-1, BAMBI knockdown, or induction of differentiation. CPX-1 knockdown compromised preadipocyte differentiation coincident with reduced collagen expression. Furthermore, preadipocytes differentiated on matrix derived from CPX-1 knockdown cells exhibited reduced Glut4 expression and insulin-stimulated glucose uptake. Finally, CPX-1 expression was increased in adipose tissue from obese mice and humans. Collectively, these findings establish CPX-1 as a positive regulator of adipogenesis situated downstream of FGF-1/BAMBI that may contribute to hyperplastic adipose tissue expansion via affecting extracellular matrix remodeling.-Kim, Y.-H., Barclay, J. L., He, J., Luo, X., O'Neill, H. M., Keshvari, S., Webster, J. A., Ng, C., Hutley, L. J., Prins, J. B., Whitehead, J. P. Identification of carboxypeptidase X (CPX)-1 as a positive regulator of adipogenesis.
Assuntos
Adipogenia/fisiologia , Tecido Adiposo/metabolismo , Regulação da Expressão Gênica/fisiologia , Glicoproteínas/metabolismo , Metaloexopeptidases/metabolismo , Adipócitos/metabolismo , Adipócitos/fisiologia , Adipogenia/efeitos dos fármacos , Adulto , Animais , Diferenciação Celular , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/efeitos adversos , Feminino , Fator 1 de Crescimento de Fibroblastos/genética , Fator 1 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Glicoproteínas/genética , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Metaloexopeptidases/genética , Camundongos , Pessoa de Meia-Idade , Obesidade/etiologia , Obesidade/metabolismoRESUMO
Macrophage and osteoclast proliferation, differentiation and survival are regulated by colony-stimulating factor-1 receptor (CSF1R) signaling. Osteopetrosis associated with Csf1 and Csf1r mutations has been attributed to the loss of osteoclasts and deficiency in bone resorption. Here we demonstrate that homozygous Csf1r mutation in rat leads to delayed postnatal skeletal ossification associated with substantial loss of osteal macrophages (osteomacs) in addition to osteoclasts. Osteosclerosis and site-specific skeletal abnormalities were reversed by intraperitoneal transfer of wild-type bone marrow cells (BMT) at weaning. Following BMT, IBA1+ macrophages were detected before TRAP+ osteoclasts at sites of ossification restoration. These observations extend evidence that osteomacs independently contribute to bone anabolism and are required for normal postnatal bone growth and morphogenesis.
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The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic islets and promote secretion of high-quality insulin from beta-cells. However, the endogenous role of IL-22RA1 signaling on these cells remains unclear. Here, we show that antibody neutralisation of IL-22RA1 in cultured human islets leads to impaired insulin quality and increased cellular stress. Through the generation of mice lacking IL-22ra1 specifically on pancreatic alpha- or beta-cells, we demonstrate that ablation of murine beta-cell IL-22ra1 leads to similar decreases in insulin secretion, quality and islet regeneration, whilst increasing islet cellular stress, inflammation and MHC II expression. These changes in insulin secretion led to impaired glucose tolerance, a finding more pronounced in female animals compared to males. Our findings attribute a regulatory role for endogenous pancreatic beta-cell IL-22ra1 in insulin secretion, islet regeneration, inflammation/cellular stress and appropriate systemic metabolic regulation.
Assuntos
Glucose , Homeostase , Células Secretoras de Insulina , Insulina , Camundongos Knockout , Receptores de Interleucina , Animais , Células Secretoras de Insulina/metabolismo , Receptores de Interleucina/metabolismo , Receptores de Interleucina/genética , Feminino , Humanos , Masculino , Insulina/metabolismo , Camundongos , Glucose/metabolismo , Secreção de Insulina , Camundongos Endogâmicos C57BL , Interleucina 22 , Intolerância à Glucose/metabolismo , Interleucinas/metabolismo , Interleucinas/genética , Envelhecimento/metabolismoRESUMO
Metabolic dysfunction-associated steatohepatitis (MASH) is the most prevalent cause of liver disease worldwide, with a single approved therapeutic. Previous research has shown that interleukin-22 (IL-22) can suppress ß-cell stress, reduce local islet inflammation, restore appropriate insulin production, reverse hyperglycemia, and ameliorate insulin resistance in preclinical models of diabetes. In clinical trials long-acting forms of IL-22 have led to increased proliferation in the skin and intestine, where the IL-22RA1 receptor is highly expressed. To maximise beneficial effects whilst reducing the risk of epithelial proliferation and cancer, we designed short-acting IL-22-bispecific biologic drugs that successfully targeted the liver and pancreas. Here we show 10-fold lower doses of these bispecific biologics exceed the beneficial effects of native IL-22 in multiple preclinical models of MASH, without off-target effects. Treatment restores glycemic control, markedly reduces hepatic steatosis, inflammation, and fibrogenesis. These short-acting IL-22-bispecific targeted biologics are a promising new therapeutic approach for MASH.
Assuntos
Fígado Gorduroso , Interleucina 22 , Interleucinas , Fígado , Pâncreas , Interleucinas/metabolismo , Animais , Fígado/metabolismo , Fígado/patologia , Fígado/efeitos dos fármacos , Pâncreas/patologia , Pâncreas/metabolismo , Pâncreas/efeitos dos fármacos , Humanos , Camundongos , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Resistência à Insulina , Receptores de Interleucina/metabolismoRESUMO
Adiponectin is a beneficial adipokine with insulin-sensitizing, anti-inflammatory and anti-atherogenic effects. These effects are mediated by two poorly characterised, closely related, atypical seven-transmembrane receptors. In the current report we have used C-terminal, epitope-tagged AdipoR1 and AdipoR2 constructs to monitor cell-surface expression by indirect immunofluorescence microscopy and quantitative plate-based analysis. We demonstrate that only AdipoR1 is constitutively expressed on the cell-surface. Further investigations, involving characterisation of a number of chimeric and truncated constructs, show the non-conserved region of AdipoR2 (residues 1-81) restricts its cell-surface expression. Introduction or deletion of this region, into AdipoR1 or AdipoR2, resulted in inhibition or promotion of cell-surface expression, respectively. We also confirmed that AdipoR1 and AdipoR2 can form heterodimers when co-expressed and that co-expression leads to the cell-surface expression of AdipoR2. Collectively these studies demonstrate that the non-conserved region of AdipoR2 restricts its cell-surface expression and raise the possibility that the majority of cell-surface AdipoR2 may be present in the form of heterodimers.
Assuntos
Membrana Celular/metabolismo , Receptores de Adiponectina/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Humanos , Dados de Sequência Molecular , Multimerização Proteica , Estrutura Terciária de Proteína , Receptores de Adiponectina/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Macrophages are an abundant cell population in the placenta and developing embryo and appear to be involved in processes of vascularization, morphogenesis, organogenesis, and hematopoiesis. The proliferation, differentiation, and survival are dependent on signals from the macrophage colony-stimulating factor receptor, CSF1R. Aside from the role in macrophages, Csf1r mRNA is highly expressed in placental trophoblasts. To explore the function of macrophages and Csf1r in placental and embryonic development, we analyzed the impact of homozygous Csf1r null mutation (Csf1rko) in the rat. In late gestation, IBA1+ macrophages were abundant in control embryos in all tissues, including the placenta, and greatly reduced in the Csf1rko. CSF1R was also detected in stellate macrophage-like cells and in neurons using anti-CSF1R antibody but was undetectable in trophoblasts. However, the neuronal signal was not abolished in the Csf1rko. CD163 was most abundant in cells forming the center of erythroblastic islands in the liver and was also CSF1R dependent. Despite the substantial reduction in macrophage numbers, we detected no effect of the Csf1rko on development of the placenta or any organs, the relative abundance of vascular elements (CD31 staining), or cell proliferation (Ki67 staining). The loss of CD163+ erythroblastic island macrophages in the liver was not associated with anemia or any reduction in the proliferative activity in the liver, but there was a premature expansion of CD206+ cells, presumptive precursors of liver sinusoidal endothelial cells. We suggest that many functions of macrophages in development of the placenta and embryo can be provided by other cell types in their absence.
Assuntos
Células Endoteliais , Placenta , Ratos , Feminino , Animais , Gravidez , Células Endoteliais/metabolismo , Placenta/metabolismo , Macrófagos/metabolismo , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Desenvolvimento Embrionário , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Macrófagos/metabolismoRESUMO
Resident and recruited macrophages control the development and proliferation of the liver. We have previously shown in multiple species that treatment with a macrophage colony stimulating factor (CSF1)-Fc fusion protein initiated hepatocyte proliferation and promoted repair in models of acute hepatic injury in mice. Here, we investigated the impact of CSF1-Fc on resolution of advanced fibrosis and liver regeneration, using a non-resolving toxin-induced model of chronic liver injury and fibrosis in C57BL/6J mice. Co-administration of CSF1-Fc with exposure to thioacetamide (TAA) exacerbated inflammation consistent with monocyte contributions to initiation of pathology. After removal of TAA, either acute or chronic CSF1-Fc treatment promoted liver growth, prevented progression and promoted resolution of fibrosis. Acute CSF1-Fc treatment was also anti-fibrotic and pro-regenerative in a model of partial hepatectomy in mice with established fibrosis. The beneficial impacts of CSF1-Fc treatment were associated with monocyte-macrophage recruitment and increased expression of remodelling enzymes and growth factors. These studies indicate that CSF1-dependent macrophages contribute to both initiation and resolution of fibrotic injury and that CSF1-Fc has therapeutic potential in human liver disease.
Assuntos
Hepatopatias , Fator Estimulador de Colônias de Macrófagos , Animais , Fibrose , Fígado/metabolismo , Hepatopatias/patologia , Fator Estimulador de Colônias de Macrófagos/metabolismo , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Type 2 diabetes (T2D) is a well-known risk factor for tuberculosis (TB), but little is known about pre-diabetes and the relative contribution of impaired glucose tolerance vs. obesity towards susceptibility to TB. Here, we developed a preclinical model of pre-diabetes and TB. Mice fed a high fat diet (HFD) for 12 weeks presented with impaired glucose tolerance and hyperinsulinemia compared to mice fed normal chow diet (NCD). Infection with M. tuberculosis (Mtb) H37Rv after the onset of dysglycemia was associated with significantly increased lung pathology, lower concentrations of TNF-α, IFN-γ, IFN-ß and IL-10 and a trend towards higher bacterial burden at 3 weeks post infection. To determine whether the increased susceptibility of pre-diabetic mice to TB is reversible and is associated with dysglycemia or increased body fat mass, we performed a diet reversal experiment. Pre-diabetic mice were fed a NCD for 10 additional weeks (HFD/NCD) at which point glucose tolerance was restored, but body fat mass remained higher compared to control mice that consumed NCD throughout the entire experiment (NCD/NCD). Upon Mtb infection HFD/NCD mice had significantly lower bacterial burden compared to NCD/NCD mice and this was accompanied by restored IFN-γ responses. Our findings demonstrate that pre-diabetes increases susceptibility to TB, but a high body mass index without dysglycemia is protective. This murine model offers the opportunity to further study the underlying immunological, metabolic and endocrine mechanisms of this association.
Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Intolerância à Glucose , Estado Pré-Diabético , Tuberculose , Tecido Adiposo , Animais , Dieta Hiperlipídica/efeitos adversos , Camundongos , Camundongos Endogâmicos C57BL , Índice de Gravidade de DoençaRESUMO
PURPOSE: To identify glucocorticoid-responsive proteins measurable in human serum that may have clinical utility in therapeutic drug monitoring and the diagnosis of cortisol excess or deficiency. EXPERIMENTAL DESIGN: A phased biomarker discovery strategy was conducted in two cohorts. Secretome from peripheral blood mononuclear cells (PBMC) isolated from six volunteers after ex vivo incubation ± dexamethasone (DEX) 100 ng/mL for 4 h and 24 h was used for candidate discovery and qualification using untargeted proteomics and a custom multiple reaction monitoring mass spectrometry (MRM-MS) assay, respectively. For validation, five candidates were measured by immunoassay in serum from an independent cohort (n = 20), sampled at 1200 h before and after 4 mg oral DEX. RESULTS: The discovery secretome proteomics data generated a shortlist of 45 candidates, with 43 measured in the final MRM-MS assay. Differential analysis revealed 16 proteins that were significant in at least one of two time points. In the validation cohort, 3/5 serum proteins were DEX-responsive, two significantly decreased: lysozyme C (p < 0.0001) and nucleophosmin-1 (p < 0.01), while high mobility group box 2 significantly increased (p < 0.01). CONCLUSIONS AND CLINICAL RELEVANCE: Using an ex vivo proteomic approach in PBMC, we have identified circulating glucocorticoid-responsive proteins which may have potential as serum biomarkers of glucocorticoid activity.