Project description:Macrophages adopt an alternatively activated phenotype (AAM) when activated by IL-4. While these AAMs can be derived from local proliferation of resident tissue macrophages or recruited inflammatory monocytes, it is not known whether these different AAMs are phenotypically and functionally distinct. Using microarray analysis of gene expression, we demonstrated that while both monocyte- and tissue-derived AAM expressed high levels of Arg1, Chi3l3 and Retnla, only monocyte-derived AAM upregulated Raldh2 and PD-L2. The distinction between monocyte- and tissue-derived macrophages can, therefore, be made using different phenotypic markers. Gene expression profiling analysis with whole genome microarray of tissue-derived and monocyte-derived macrophages, induced using IL-4c and/or 4% thioglycollate.
Project description:Macrophages adopt an alternatively activated phenotype (AAM) when activated by IL-4. While these AAMs can be derived from local proliferation of resident tissue macrophages or recruited inflammatory monocytes, it is not known whether these different AAMs are phenotypically and functionally distinct. Using microarray analysis of gene expression, we demonstrated that while both monocyte- and tissue-derived AAM expressed high levels of Arg1, Chi3l3 and Retnla, only monocyte-derived AAM upregulated Raldh2 and PD-L2. The distinction between monocyte- and tissue-derived macrophages can, therefore, be made using different phenotypic markers.
Project description:Long recognized as an evolutionarily ancient cell type involved in tissue homeostasis and immune defense against pathogens, macrophages are being rediscovered as regulators of several diseases including cancer. Here we show that in mice, mammary tumor growth induces the accumulation of tumor-associated macrophages (TAMs) that are phenotypically and functionally distinct from mammary tissue macrophages (MTMs). TAMs express the adhesion molecule Vcam1 and proliferate upon their differentiation from inflammatory monocytes, but do not exhibit an “alternatively activated” phenotype. TAM differentiation depends on the transcriptional regulator of Notch signaling, RBPJ; and TAM, but not MTM, depletion restores tumor-infiltrating cytotoxic T cell responses and suppresses tumor growth. These findings reveal the ontogeny of TAMs and a discrete tumor-elicited inflammatory response, which may provide new opportunities for cancer immunotherapy.
Project description:Long recognized as an evolutionarily ancient cell type involved in tissue homeostasis and immune defense against pathogens, macrophages are being rediscovered as regulators of several diseases including cancer. Here we show that in mice, mammary tumor growth induces the accumulation of tumor-associated macrophages (TAMs) that are phenotypically and functionally distinct from mammary tissue macrophages (MTMs). TAMs express the adhesion molecule Vcam1 and proliferate upon their differentiation from inflammatory monocytes, but do not exhibit an “alternatively activated” phenotype. TAM differentiation depends on the transcriptional regulator of Notch signaling, RBPJ; and TAM, but not MTM, depletion restores tumor-infiltrating cytotoxic T cell responses and suppresses tumor growth. These findings reveal the ontogeny of TAMs and a discrete tumor-elicited inflammatory response, which may provide new opportunities for cancer immunotherapy. MMTV-PyMT mice (Jackson Laboratory) were backcrossed to the C57BL/6 background for 10 generations. Rbpjfl/fl mice were provided by Tasuku Honjo and crossed to CD11ccre mice provided by Boris Reizis. Littermate controls were used in all experiments when possible. All mice were maintained in a specific pathogen-free facility and animal experimentation was conducted in accordance with institutional guidelines. In the MMTV-PyMT spontaneous mammary tumor model, we found the key Notch transcriptional regulator, RBPJ, to be required for TAM terminal differentiation from inflammatory monocytes. The bulk myeloid cell population that remains in CD11cCreRbpj fl/fl mice (the cells in "Rbpj KO" samples), represents monocytes that have begun their differentiation into macrophages, but are unable to terminally differentiate due to the lack of Rbpj.
Project description:In this study, by using two classical macrophage cell models, RAW264.7 cell line from mouse and THP-1 cell line from human, combined with the applications of two classical stimulation methods for inducing classical activated (M1) and alternatively activated macrophages (M2) from the monocytes of both cell lines, we comprehensively identified and quantified proteins in different types of macrophages from both cell lines through high-throughput proteomics.
Project description:Background: Obesity is associated with infiltration of macrophages into adipose tissue. Adipose macrophages may contribute to an elevated inflammatory status by secreting a variety of pro-inflammatory mediators, including TNFalpha and IL-6. Recent data suggest that during diet-induced obesity the phenotype of adipose-resident macrophages changes from alternatively activated macrophages towards a more classical and pro-inflammatory phenotype. Here, we explore the effect of PPARγ-activation on obesity-induced inflammation in 129SV mice fed a high fat diet for 20 weeks. High fat feeding increased bodyweight gain, adipose tissue mass and liver triglycerides. Rosiglitazone treatment further increased adipose mass, reduced liver triglycerides and changed adipose tissue morphology towards smaller adipocytes. Surprisingly, rosiglitazone markedly increased the number of macrophages in adipose tissue, as shown by immunohistochemical analysis and quantification of macrophage marker genes CD68 and F4/80+. In adipose tissue, markers for classically activated macrophages including IL-18 were down regulated whereas markers characteristic for alternatively activated macrophages (Arginase 1, IL-10) were up regulated by rosiglitazone. Importantly, conditioned media from rosiglitazone-treated alternatively activated macrophages neutralized the inhibitory effect of macrophages on 3T3-L1 adipocyte differentiation, suggesting that alternatively activated macrophages may be involved in mediating the effects of rosiglitazone on adipose tissue morphology and mass. Our results suggest that short term rosiglitazone treatment increases infiltration of alternatively activated macrophages in adipose tissue. The alternatively activated macrophages might play a role in PPARγ-dependent expansion and remodeling of adipose tissue. Keywords: metabolic state analysis
Project description:Tissue macrophages derive from bone marrow monocytes, and recent studies using mice have revealed that they also derive from yolk sac precursors or fetal liver monocytes. However, embryo-derived macrophages are supposed to be more important to maintain tissue macrophage pool because they can self-renew. Here, we show that adult bone marrow-derived macrophages (MDM) also retain the ability of self-renewal. Where they were readily obtained by a long-term culture: mouse bone marrow cells were cultured with macrophage colony-stimulating factor (M-CSF). After several passages, most MDM died owing to their limited life span with survival and expansion of self-renewing macrophages resided in a small fraction. Self-renewing macrophages were not tumorigenic, but proliferate for a long period in almost unlimited numbers. Despite being distinct from MDM, they were phenotypically and functionally differentiated macrophages, and could differentiate into dendritic cells or osteoclasts. Moreover, Krüppel-like Factor 2 (KLF2) involved in self-renewal of embryonic stem cells, was markedly up-regulated by M-CSF-stimulation in self-renewing macrophages, which was accompanied with a gradual down-regulation of MafB, a suppressor of KLF2 expression. Importantly, knockdown of KLF2 as well as c-Myc caused cell cycle arrest, apoptosis, and diminished cell growth. Our culture method results suggest the presence of precursor(s) for self-renewing macrophages in adult bone marrow that can be used to describe discrepancy of adult- and embryo-derived macrophages. Microarray data from both monocyte-derived and bone marrow-derived mouse macrophages are used to detail the global gene expression profile underlying phenotype, function and self-renewal capacity in order to unravel difference/similarity in phenotype/function and mechanism/degree of self-renewal between the two distinct macrophages.
Project description:Host-environment interfaces such as the dermis comprise tissue macrophages as the most abundant resident immune cell type. Diverse tasks, i.e. to resist against invading pathogens, to attract bypassing immune cells from penetrating vessels and to aid tissue development and repair require a dynamic postnatal coordination of tissue macrophages specification. Here, we delineated the postnatal development of dermal macrophages and their differentiation into distinct subsets by adapting single cell transcriptomics, fate-mapping and tissue imaging. We thereby identified a small phenotypically and transcriptionally distinct subset of embryo-derived skin macrophages that was maintained and largely excluded from the overall postnatal exchange by monocytes. These macrophages specifically interacted with dermal sensory nerves, surveilled and trimmed the myelin sheets and regulated axon sprouting after mechanical injury. In summary, our data show long-lasting functional specification of macrophages in the dermis that is driven by step-wise adaptation to guiding structures and ensures codevelopment of ontogenetically distinct cells within the same compartment.