Colony-stimulating Factor Receptor mRNA Research Articles

CSF1R regulates schizophrenia-related stress response and vascular association of microglia/macrophages

BackgroundMicroglia are known to regulate stress and anxiety in both humans and animal models. Psychosocial stress is the most common risk factor for the development of schizophrenia. However, how microglia/brain macrophages contribute to schizophrenia is not well established. We hypothesized that effector molecules expressed in microglia/macrophages were involved in schizophrenia via regulating stress susceptibility.MethodsWe recruited a cohort of first episode schizophrenia (FES) patients (n = 51) and age- and sex-paired healthy controls (HCs) (n = 46) with evaluated stress perception. We performed blood RNA-sequencing (RNA-seq) and brain magnetic resonance imaging, and measured plasma level of colony stimulating factor 1 receptor (CSF1R). Furthermore, we studied a mouse model of chronic unpredictable stress (CUS) combined with a CSF1R inhibitor (CSF1Ri) (n = 9 ~ 10/group) on anxiety behaviours and microglial biology.ResultsFES patients showed higher scores of perceived stress scale (PSS, p < 0.05), lower blood CSF1R mRNA (FDR = 0.003) and protein (p < 0.05) levels, and smaller volumes of the superior frontal gyrus and parahippocampal gyrus (both FDR < 0.05) than HCs. In blood RNA-seq, CSF1R-associated differentially expressed blood genes were related to brain development. Importantly, CSF1R facilitated a negative association of the superior frontal gyrus with PSS (p < 0.01) in HCs but not FES patients. In mouse CUS+CSF1Ri model, similarly as CUS, CSF1Ri enhanced anxiety (both p < 0.001). Genes for brain angiogenesis and intensity of CD31+-blood vessels were dampened after CUS-CSF1Ri treatment. Furthermore, CSF1Ri preferentially diminished juxta-vascular microglia/macrophages and induced microglia/macrophages morphological changes (all p < 0.05).ConclusionMicroglial/macrophagic CSF1R regulated schizophrenia-associated stress and brain angiogenesis.

Regulation of colony-stimulating factor 1 receptor inhibitor pexidartinib on the senescence of mouse bone marrow-derived macrophages stimulated by lipopolysaccharide

Objective: To investigate the effects of colony-stimulating factor 1 receptor (CSF-1R) inhibitor pexidartinib (PLX3397) on the senescence of bone marrow-derived macrophages (BMDM) stimulated by lipopolysaccharide (LPS). Methods: BMDM were isolated and cultured from femurs and tibiae of 10 male C57BL/6 mice aged 6-8 weeks (obtained from Laboratory Animal Center of Guizhou Medical University). They were divided into blank control group, LPS group (treated with 1 μg/ml LPS for 24 h) as well as low, medium and high concentration PLX3397 pretreatment groups (treated with 100, 500 and 1 000 nmol/L PLX3397 for 4 h respectively followed by 1 μg/ml LPS for 24 h). The corresponding markers of macrophages were detected by flow cytometry. Cell viability was detected by cell counting kit-8 and cellular senescence was detected by senescence-associated-β-galactosidase (SA-β-gal) staining. Meanwhile, protein expressions of cycle-dependent kinase inhibitor p16, p21 and CSF-1R were detected by Western blotting, and the expressions of p16 and p21 were detected by intracellular immunofluorescence. Real-time fluorescence quantitative PCR (RT-qPCR) was used to investigate the mRNA levels of senescence-associated secretory phenotype (SASP) genes including interleukin (IL), IL-1β, chemokine-1/10 (CXCL-1/10), matrix metalloproteinase-8 (MMP-8), and transforming growth factor-β (TGF-β). Results: The rate of SA-β-gal positive staining in medium and high concentration PLX3397 pretreatment groups [(39.33±4.93)% and (36.33±3.06)% respectively] were significantly downregulated compared with LPS group [(52.00±3.00)%] (P=0.020, P=0.005). The expression of CSF-1R protein in low, medium and high concentration PLX3397 pretreatment groups were (0.74±0.18, 0.61±0.07, 0.54±0.06), all of which were significantly lower than that in LPS group (1.16±0.08) (P=0.013, P=0.002, P<0.001). The expression levels of CSF-1R mRNA in low, medium and high concentration PLX3397 pretreatment groups (1.04±0.06, 0.90±0.05, 1.18±0.08) showed similar trend (2.90±0.25) (P<0.001). The average fluorescence intensity of p16 in all PLX3397 pretreatment groups were 49.76±3.65, 48.21±1.72, 47.99±1.26 respectively, which were significantly lower than that in LPS group (66.88±5.85) (P=0.001, P<0.001, P<0.001). The average fluorescence intensity of p21 in medium and high concentration PLX3397 pretreatment groups were (34.43±3.62, 30.13±0.86), significantly lower than that in LPS group (46.82±5.33) (P=0.043, P=0.007). The expression of p16 protein in low, medium and high concentration PLX3397 pretreatment groups (0.56±0.04, 0.55±0.04, 0.35±0.19) were significantly lower than that in LPS group (0.98±0.10) (P=0.003, P=0.002, P<0.001), as well the expression of p21 protein (0.69±0.20, 0.42±0.08, 0.26±0.14) (P=0.032, P=0.002, P<0.001). According to the results of RT-qPCR, the expressions of IL-6, IL-1β, CXCL-1, CXCL-10 and MMP-8 in PLX3397 pretreatment groups were significantly lower than those in LPS group (P<0.001), while the expression of TGF-β increased (P<0.001). Conclusions: LPS could induce the cell senescence, increase the secretion of SASP and aggravate local inflammation by activating the CSF-1R on the cell surface of bone marrow-derived macrophages. CSF-1R inhibitor PLX3397 might attenuate CSF-1R activation associated with LPS and inhibit the senescence of bone marrow-derived macrophages induced by LPS.

Differential regulation of TREM2 and CSF1R in CNS macrophages in an SIV/macaque model of HIV CNS disease.

HIV-associated neuroinflammation is primarily driven by CNS macrophages including microglia. Regulation of these immune responses, however, remains to be characterized in detail. Using the SIV/macaque model of HIV, we evaluated CNS expression of triggering receptor expressed on myeloid cells 2 (TREM2) which is constitutively expressed by microglia and contributes to cell survival, proliferation, and differentiation. Loss-of-function mutations in TREM2 are recognized risk factors for neurodegenerative diseases including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Nasu-Hakola disease (NHD); recent reports have also indicated a role for TREM2 in HIV-associated neuroinflammation. Using in situ hybridization (ISH) and qRT-PCR, TREM2 mRNA levels were found to be significantly elevated in frontal cortex of macaques with SIV encephalitis compared with uninfected controls (P = 0.02). TREM2 protein levels were also elevated as measured by ELISA of frontal cortex tissue homogenates in these animals. Previously, we characterized the expression of CSF1R (colony-stimulating factor 1 receptor) in this model; the TREM2 and CSF1R promoters both contain a PU.1 binding site. While TREM2 and CSF1R mRNA levels in the frontal cortex were highly correlated (Spearman R = 0.79, P < 0.001), protein levels were not well correlated. In SIV-infected macaques released from ART to study viral rebound, neither TREM2 nor CSF1R mRNA increased with rebound viremia. However, CSF1R protein levels remained significantly elevated unlike TREM2 (P = 0.02). This differential expression suggests that TREM2 and CSF1R play unique, distinct roles in the pathogenesis of HIV CNS disease.

Increased Microglial CSF1R Expression in the SIV/Macaque Model of HIV CNS Disease.

Chronic microglial activation and associated neuroinflammation are key factors in neurodegenerative diseases including HIV-associated neurocognitive disorders. Colony stimulating factor 1 receptor (CSF1R)-mediated signaling is constitutive in cells of the myeloid lineage, including microglia, promoting cell survival, proliferation, and differentiation. In amyotrophic lateral sclerosis and Alzheimers disease, CSF1R is upregulated. Inhibiting CSF1R signaling in animal models of these diseases improved disease outcomes. In our studies, CNS expression of the CSF1R ligand, colony-stimulating factor 1 (CSF1) was significantly increased in a SIV/macaque model of HIV CNS disease. Using a Nanostring nCounter immune panel, we found CSF1 overexpression was strongly correlated with upregulation of microglial genes involved in antiviral and oxidative stress responses. Using in situ hybridization, we found that CSF1R mRNA was only present in Iba-1 positive microglia. By ELISA and immunostaining with digital image analysis, SIV-infected macaques had significantly higher CSF1R levels in frontal cortex than uninfected macaques (p = 0.018 and p = 0.02, respectively). SIV-infected macaques treated with suppressive ART also had persistently elevated CSF1R similar to untreated SIV-infected macaques. Coordinate upregulation of CSF1 and CSF1R expression implicates this signaling pathway in progressive HIV CNS disease.

Macrophage Susceptibility to Emactuzumab (RG7155) Treatment.

Blockade of colony-stimulating factor-1 receptor (CSF-1R) enables the therapeutic targeting of tumor-associated macrophages (TAM) in cancer patients. Various CSF-1R inhibitors, mAbs, and tyrosine kinase inhibitors are currently evaluated in early clinical trials. Presence of an alternative survival signal, such as GM-CSF, rescues human monocyte-derived macrophages from CSF-1R inhibitor-induced apoptosis. In this study, we sought to identify additional factors that mediate resistance to CSF-1R-blocking antibody RG7155 (emactuzumab). We investigated the impact of hypoxia, macrophage-polarizing cytokines IL4 and IL10, and genetic alterations within the CSF1R locus and mitochondrial DNA. Among all investigated factors, only IL4 completely rescued viability of RG7155-treated macrophages in vitro This RG7155-resistant population was characterized by a substantially increased mannose receptor-1 (CD206) expression. Analysis of CD206 and the hemoglobin scavenger receptor CD163 expression on normal tissue allowed for discrimination of distinct macrophage populations according to localization and frequency. In emactuzumab-treated cancer patients, we found a significant reduction of CSF-1R, CD204, and CD163 mRNA levels in contrast to a less pronounced decrease of CD206 expression by transcriptome analysis of tumor biopsies. However, we detected in normal skin tissue, which shows lower IL4 mRNA expression compared with melanoma tissue, significant reduction of CD206+ dermal macrophages in RG7155-treated skin biopsies. These results suggest that in cancers where the cytokines IL4 and GM-CSF are sufficiently expressed to induce very high CD206 expression on macrophages, CSF-1R inhibition may not deplete CD206hi TAM. This observation can help to identify those patients most likely to benefit from CSF-1R-targeting agents. Mol Cancer Ther; 15(12); 3077-86. ©2016 AACR.

Identification of an Isoform of Colony-Stimulating Factor 1 Receptor mRNA in the Rat Testis

Because alternative RNA splicing regulation in the testis is prevalent, we explored testes of Sprague-Dawley rats for existence of alternatively spliced colony-stimulating factor 1 receptor (CSF-1R) mRNA. Using RT-PCR and sequencing, we identified a variant of CSF-1R mRNA that was 284 bp shorter than the full-length CSF-1R transcript. This variant was present in the testis (late fetal stage to adult) and in other organs of rats (7 and 60 days old). The deletion of 284 bp disrupted the open reading frame, resulting in a noncoding mRNA product. When testicular macrophages were stimulated with CSF-1R ligand and lipopolysaccharide, proportionally increased expression of both short isoform and full-length CSF-1R mRNA was observed. Thus, the identified isoform of CSF-1R mRNA may interfere with the expression of full-length CSF-1R mRNA, thereby affecting the biological activity of the ligand/receptor signaling axis in Sprague-Dawley rats.

Differential mucosal expression of IL-34 gene in acute and chronic intestinal inflammation (117.8)

Abstract An imbalance of mucosal pro- and anti-inflammatory cytokines is crucial in the pathogenesis of inflammatory bowel disease (IBD). IL-34, a newly discovered cytokine involved in macrophage differentiation, induces the production of macrophage chemoattractant protein (MCP)-1 and eotaxin-2 from primary macrophages. The present ongoing study compared mRNA and protein levels of IL-34, mRNA expression of its cognate receptor colony stimulating factor-1 receptor (CSF-1R) and MCP-1 in intestinal biopsies from controls, Crohn’s disease (CD) and ulcerative colitis (UC) patients. Evaluation of mRNA levels revealed that unlike CD, IL-34 mRNA was 5-fold elevated in UC samples, suggesting that IL-34 could be a potential marker for UC pathogenesis. IL-34 protein levels however, did not mirror mRNA levels suggesting post-transcriptional modification. Interestingly in UC, CSF-1R mRNA varied reciprocally to IL-34, suggesting that like IL-34, CSF-1R could be subjected to post transcriptional modification. Micro RNA database revealed that miR-155 was a predicted candidate to block CSF-1R translation. Low CSF-1R expression correlated with very high levels of miR-155 emphasizing the concept of microRNA mediated regulation. MiR-155 levels in CD were down regulated and varied reciprocally with CSF-1R. MCP-1 was elevated in both IBD patients. Our findings suggest that IL-34 mediated immune regulation is different in UC and CD, which might have important consequences for therapeutic intervention.

Association between colony-stimulating factor 1 receptor gene polymorphisms and asthma risk

Colony-stimulating factor 1 receptor (CSF1R) is expressed in monocytes/macrophages and dendritic cells. These cells play important roles in the innate immune response, which is regarded as an important aspect of asthma development. Genetic alterations in the CSF1R gene may contribute to the development of asthma. We investigated whether CSF1R gene polymorphisms were associated with the risk of asthma. Through direct DNA sequencing of the CSF1R gene, we identified 28 single nucleotide polymorphisms (SNPs) and genotyped them in 303 normal controls and 498 asthmatic patients. Expression of CSF1R protein and mRNA were measured on CD14-positive monocytes and neutrophils in peripheral blood of asthmatic patients using flow cytometry and real-time PCR. Among the 28 polymorphisms, two intronic polymorphism (+20511C>T and +22693T>C) were associated with the risk of asthma by logistic regression analysis. The frequencies of the minor allele at CSF1R +20511C>T and +22693T>C were higher in asthmatic subjects than in normal controls (4.6 vs. 7.7%, p = 0.001 in co-dominant and dominant models; 16.4 vs. 25.8%, p = 0.0006 in a recessive model). CSF1R mRNA levels in neutrophils of the asthmatic patients having the +22693CC allele were higher than in those having the +22693TT allele (p = 0.026). Asthmatic patients with the +22693CC allele also showed significantly higher CSF1R expression on CD14-positive monocytes and neutrophils than did those with the +22693TT allele (p = 0.045 and p = 0.044). The +20511C>T SNP had no association with CSF1R mRNA or protein expression. In conclusion, the minor allele at CSF1R +22693T>C may have a susceptibility effect in the development of asthma, via increased CSF1R protein and mRNA expression in inflammatory cells.Electronic supplementary materialThe online version of this article (doi:10.1007/s00439-010-0850-3) contains supplementary material, which is available to authorized users.

High Expression of Macrophage Colony-Stimulating Factor-1 Receptor in Peritumoral Liver Tissue Is Associated with Poor Outcome in Hepatocellular Carcinoma After Curative Resection

Macrophage colony-stimulating factor 1 receptor (CSF-1R) expression in hepatocellular carcinoma (HCC) and its prognostic values are unclear. This study evaluated the prognostic values of the intratumoral and peritumoral expression of CSF-1R in HCC patients after curative resection. Tissue microarrays containing material from cohort 1 (105 patients) and cohort 2 (32 patients) were constructed. Immunohistochemistry was performed and prognostic values of these and other clinicopathological data were evaluated. The CSF-1R mRNA level was assessed by quantitative real-time polymerase chain reaction in cohort 3 (52 patients). Both the CSF-1R density and its mRNA level were significantly higher in peritumoral liver tissue than in the corresponding tumor tissue. CSF-1R was distributed in a gradient in the long-distance peritumoral tissue microarray, with its density decreasing as the distance from the tumor margin increased. High peritumoral CSF-1R was significantly associated with more intrahepatic metastases and poorer survival. Peritumoral CSF-1R was an independent prognostic factor for both overall survival and time to recurrence and affected the incidence of early recurrence. However, intratumoral CSF-1R did not correlate with any clinicopathological feature. Peritumoral CSF-1R was also associated with both overall survival and time to recurrence in a subgroup with small HCCs (< or =5 cm). Peritumoral CSF-1R is associated with intrahepatic metastasis, tumor recurrence, and patient survival after hepatectomy, highlighting the critical role of the peritumoral liver milieu in HCC progression. CSF-1R may become a potential therapeutic target for postoperative adjuvant treatment.

Coordinate Expression of Colony-Stimulating Factor-1 and Colony-Stimulating Factor-1-Related Proteins Is Associated with Poor Prognosis in Gynecological and Nongynecological Leiomyosarcoma

Previously, we showed that the presence of high numbers of macrophages correlates with poor prognosis in nongynecological leiomyosarcoma (LMS). In gynecological LMS, a similar trend was noted but did not reach statistical significance. Colony-stimulating factor-1 (CSF1) is a major chemoattractant for macrophages. Here we show that in a subset of LMS cases, CSF1 is expressed by the malignant cells. Previously, we found that CSF1 is translocated and highly expressed in tenosynovial giant cell tumors (TGCTs), and this observation allowed us to identify genes that showed a coordinate expression with CSF1. Here, we evaluated the expression of CSF1 and TGCT-associated proteins in 149 cases of LMS. The coordinate expression of CSF1 and three TGCT-associated proteins (CD163, FCGR3a, and CTSL1) identified cases with poor prognosis in both gynecological LMS (P = 0.00006) and nongynecological LMS (P = 0.03). In gynecological LMS, the coordinate expression of these four markers was the only independent prognosticator in multivariate analysis (hazard ratio, 4.2; 95% CI, 1.12 to 16; P = 0.03). Our findings indicate that CSF1 may play an important role in the clinical behavior of LMS that may open a window for new therapeutic reagents.

Response of amoeboid microglia/brain macrophages in fetal rat brain exposed to a teratogen.

This study examined the time course response of amoeboid microglia/brain macrophages in the rat fetus induced by a single intraperitoneal injection of cyclophosphamide, a teratogen, into the mother rat at 13 days of gestation. Compared to the normal fetal brain, a marked increase in amoeboid microglia was observed in the telencephalon and diencephalon of experimental fetuses, especially in those killed at embryonic day 15. Conglomerations of microglia occurred in the dorsal and superior neuroepithelium of diencephalon, basal telencephalon, cortical neuroepithelium, and hippocampal formation as identified with OX-42, OX-18, and ED-1 by immunohistochemistry. Rhodamine isothiocynate (RhIc) as a tracer was injected via the tail vein into the pregnant rat to assess the phagocytic capability of these cells. Following the tracer injection, none of microglial cells in normal fetal brain was detectable. RhIc, however, was readily taken up by amoeboid microglia in fetal brain with injury insult. Double labeling has shown that the RhIc-labeled cells were immunoreactive with ED-1, OX-42, OX-18, and OX-6, confirming their microglial nature. Microglial proliferation was assessed by immunohistochemistry using bromodeoxyuridine, which showed a marked increase in mitotic activity. Confocal microscopic analysis revealed that a varying number of microglia coexpressed iNOS, macrophage colony-stimulating factor (M-CSF), and ICAM-1. RT-PCR analysis showed increased expression of M-CSF mRNA. Furthermore, colony-stimulating factor-1 receptor mRNA was localized in microglia by in situ hybridization. The present results suggest that NO along with M-CSF and ICAM-1 is involved in microglial proliferation in prenatal brain injury.

Expression of colony stimulating factor-1 receptor (CSF-1R) by CNS neurons in mice

We report that neurons in the central nervous system express colony stimulating factor-1 receptor (CSF-1R) mRNA and protein and that the expression has regional specificity. The presence of CSF-1R in neurons was demonstrated by the use of four different types of antibodies to CSF-1R and the presence of CSF-1R mRNA by in situ hybridization using oligonucleotide probe. In the steady state in most areas of the brain, CSF-1R is weakly expressed in only a few neurons. In the cerebellum, brainstem, and spinal cord, however, CSF-1R is expressed constitutively in greater numbers of neurons. After cerebral cortex ischemic injury, neurons in the area next to the ischemic lesion markedly upregulate CSF-1R. It is also upregulated in the contralateral cortex and in many other areas of the brain and spinal cord. We demonstrated that in cultures the ligand CSF-1 binds to its receptor (CSF-1R) in neurons and that reduction of the number of apoptotic neurons and potentiation of neuron survival is CSF-1 dose dependent. We propose that CSF-1/CSF-1R signaling is an important regulatory pathway between neurons, microglia, and astrocytes.

Localization and expression of CSF-1 receptor in rat dental follicle cells.

Colony-stimulating factor-1 (CSF-1) accelerates tooth eruption in rats and is localized in the dental follicle, a loose connective tissue sac that is necessary for eruption to occur. CSF-1 enhances the cellular events that occur in the follicle prior to eruption--namely, an influx of monocytes into the follicle early post-natally to form the osteoclasts needed to resorb bone for the eruption pathway. Because CSF-1 levels are at a peak at day 3 post-natally, and because CSF-1 has an autocrine effect on its own gene expression, the question remains as to what causes the subsequent decline in CSF-1 protein and mRNA after day 3 post-natally. To determine if the autocrine effect is inhibited through the CSF-1 receptor, analysis of the CSF-1 receptor mRNA levels in cultured dental follicle cells reveals that high concentrations of CSF-1 reduce the gene expression of the CSF-1 receptor. Interleukin 1 alpha, a molecule that enhances CSF-1 gene expression, has no effect on CSF-1 receptor mRNA levels. Immunostaining for the CSF-1 receptor protein shows that it is present in the dental follicle early post-natally and is either absent or greatly reduced by day 10 post-natally. Earlier studies showed that the mRNA levels of the CSF-1 receptor also parallel this time course. Thus, the above results suggest that the feedback inhibition of the autocrine effect of CSF-1 on its own expression is through the effect of CSF-1 inhibiting the translation and transcription of its receptor. In turn, these molecular interactions possibly regulate the cellular events that occur in the follicle prior to and during eruption.

Partial characterization of an immortalized human trophoblast cell-line, TCL-1, which possesses a CSF-1 autocrine loop

Many previous studies in both mouse and human placenta have implicated a role for colony stimulating factor-1 (CSF-1) in the regulation of placental development. In this study we have examined CSF-1 production by an immortalized cell line (TCL-1) derived from the choriodecidua, transfected with a retrovirus gene coding for the large-T antigen. TCL-1 cells were uniformly positive by immunocytochemistry for the composite sub-units of human chorionic g gonadotrophin (hCG) but were negative for markers of other cell types localized at the fetal-maternal interface. Gelatinase enzymes were secreted by TCL-1 cells cultured on extracellular matrix in a manner indicative of extra-villous trophoblast. Dot-blot immunoassays and ELISA indicated that CSF-1 was secreted by TCL-1 cells, at levels comparable to primary trophoblast cells and BeWo choriocarcinoma (trophoblast tumour) cells. Reverse transcriptase-polymerase chain reaction analysis confirmed the presence in TCL-1 cells of CSF-1 receptor mRNA (c-fms gene product), indicating that the components of a potential autocrine loop were present in these cells. Proliferation of TCL-1 cells was not affected by the addition of exogenous CSF-1 but was elevated in response to treatment with a CSF-1 neutralizing antibody. The immortalized cell line, TCL-1, provides a potential model in which to investigate regulation of growth and differentiation of trophoblast cells in vitro.

Colony stimulating factor-1 stimulates Ishikawa cell proliferation and lipocortin II synthesis

Proliferation of the Ishikawa human endometrial adenocarcinoma cell line is under the concerted control of oestrogen and progesterone. Here we demonstrate that Ishikawa cells express colony stimulating factor-1 (CSF-1), CSF-1 receptor mRNA and are growth stimulated by CSF-1 treatment. An early event associated with CSF-1 treatment is the induction of lipocortin II synthesis, a protein whose expression is also under oestrogen and progesterone control. However, neither CSF-1 or CSF-1 receptor mRNA appear to be modulated by oestrogen or progesterone.

Mouse mesangial cells produce colony-stimulating factor-1 (CSF-1) and express the CSF-1 receptor.

Abstract CSF-1 stimulates the survival, proliferation, and differentiation of mononuclear phagocytes and may also play a role in placental development. The expression of CSF-1 and the CSF-1 receptor (CSF-1R) and their regulation were examined in cultures of mouse mesangial cells (MC). The concentration of CSF-1 in the medium of cultured MC increased linearly with time over 24 h. IFN-gamma stimulated and dibutyryl cyclic AMP inhibited CSF-1 production in a dose-dependent manner. MC expression of CSF-1 mRNA was shown by Northern blot analysis, and CSF-1 mRNA levels were increased within 4 h of IFN-gamma addition and inhibited within 4 h of dibutyryl cyclic AMP addition. Indirect immunofluorescence indicated that 90% of the untreated cultured MC expressed CSF-1. In addition, CSF-1R expression by MC was demonstrated by immunofluorescence with anti-receptor antibody, specific binding of [125I] CSF-1, and expression of the CSF-1R mRNA by Northern blot analysis. Thus, mouse MC, specialized pericytes of non-bone marrow origin, not only produce CSF-1 but also express receptors for CSF-1. The effects of CSF-1 on MC may be important in the control of immune function in the glomerulus.

Temporal expression and location of colony-stimulating factor 1 (CSF-1) and its receptor in the female reproductive tract are consistent with CSF-1-regulated placental development.

During pregnancy the mouse uterine epithelial synthesis of the mononuclear phagocyte growth factor designated colony-stimulating factor 1 (CSF-1) is regulated by female sex steroids. To study the role of CSF-1 in the pregnant female reproductive tract, the temporal expression and cellular sites of synthesis of CSF-1 and CSF-1 receptor (CSF-1R) mRNA were determined. CSF-1 mRNA, predominantly the 2.3-kilobase (kb) form, was first detected by in situ hybridization in uterine epithelium prior to implantation on day 3 and subsequently increased, reaching a peak at days 14-15. Its expression was restricted to the uterine epithelium at all stages of gestation and was not localized to areas of implantation. CSF-1R mRNA was first detected in maternal decidua at day 6. It was expressed in the decidua basalis during placentation, after which its expression declined. At day 7.5, trophectodermal cells also expressed CSF-1R mRNA; during placentation, it was found also in the diploid trophoblasts. The high level of CSF-1R mRNA expression by trophoblast giant cells was independent of their location around the conceptus. There was a differential distribution of CSF-1R mRNA expression in the mature placenta, with expression in the giant trophoblastic layer greater than spongiotrophoblastic layer greater than labyrinthine layer until term. Yolk sac cells also expressed low levels of CSF-1R mRNA. The coincidence of uterine CSF-1 mRNA expression and CSF-1 synthesis with both placental growth and CSF-1R mRNA expression in decidual cells and trophoblasts strongly implicates CSF-1 in the regulation of placental growth and differentiation.