Airway Epithelial Cell-Derived Colony Stimulating Factor-1 Promotes Allergen Sensitization.

Airway epithelial cells (AECs) secrete innate immune cytokines that regulate adaptive immune effector cells. In allergen-sensitized humans and mice, the airway and alveolar microenvironment is enriched with colony stimulating factor-1 (CSF1) in response to allergen exposure. In this study we found that AEC-derived CSF1 had a critical role in the production of allergen reactive-IgE production. Furthermore, spatiotemporally secreted CSF1 regulated the recruitment of alveolar dendritic cells (DCs) and enhanced the migration of conventional DC2s (cDC2s) to the draining lymph node in an interferon regulatory factor 4 (IRF4)-dependent manner. CSF1 selectively upregulated the expression of the chemokine receptor CCR7 on the CSF1R+ cDC2, but not the cDC1, population in response to allergen stimuli. Our data describe the functional specification of CSF1-dependent DC subsets that link the innate and adaptive immune responses in T helper 2 (Th2) cell-mediated allergic lung inflammation.

Proximal tubule-derived colony stimulating factor-1 mediates polarization of renal macrophages and dendritic cells, and recovery in acute kidney injury.

Infiltrating cells play an important role in both the development of and recovery from acute kidney injury (AKI). Macrophages and renal dendritic cells are of particular interest because they can exhibit distinctly different functional phenotypes, broadly characterized as proinflammatory (M1) or tissue reparative (M2). Resident renal macrophages and dendritic cells participate in recovery from AKI in response to either ischemia/reperfusion or a model of selective proximal tubule injury induced by diphtheria-toxin-induced apoptosis in transgenic mice expressing the human diphtheria toxin receptor on proximal tubule cells. Colony-stimulating factor-1 (CSF-1) is an important factor mediating the recovery from AKI, and CSF-1 can stimulate macrophage and dendritic cell proliferation and polarization during the recovery phase of AKI. The kidney, and specifically the proximal tubule, is a major source of intrarenal CSF-1 production in response to AKI. We induced selective deletion of proximal tubule CSF-1 to determine its role in expansion and proliferation of renal macrophages and dendritic cells and in recovery from AKI. In both models of AKI, there was decreased M2 polarization, delayed functional and structural recovery, and increased tubulointerstitial fibrosis. Thus, intrarenal CSF-1 is an important mediator of macrophage/dendritic cell polarization and recovery from AKI.

DNA methylation screening of primary prostate tumors identifies SRD5A2 and CYP11A1 as candidate markers for assessing risk of biochemical recurrence.

BACKGROUND: Altered DNA methylation in CpG islands of gene promoters has been implicated in prostate cancer (PCa) progression and can be used to predict disease outcome. In this study, we determine whether methylation changes of androgen biosynthesis pathway (ABP)-related genes in patients' plasma cell-free DNA (cfDNA) can serve as prognostic markers for biochemical recurrence (BCR). METHODS: Methyl-binding domain capture sequencing (MBDCap-seq) was used to identify differentially methylated regions (DMRs) in primary tumors of patients who subsequently developed BCR or not, respectively. Methylation pyrosequencing of candidate loci was validated in cfDNA samples of 86 PCa patients taken at and/or post-radical prostatectomy (RP) using univariate and multivariate prediction analyses. RESULTS: Putative DMRs in 13 of 30 ABP-related genes were found between tumors of BCR (n = 12) versus no evidence of disease (NED) (n = 15). In silico analysis of The Cancer Genome Atlas data confirmed increased DNA methylation of two loci-SRD5A2 and CYP11A1, which also correlated with their decreased expression, in tumors with subsequent BCR development. Their aberrant cfDNA methylation was also associated with detectable levels of PSA taken after patients' post-RP. Multivariate analysis of the change in cfDNA methylation at all of CpG sites measured along with patient's treatment history predicted if a patient will develop BCR with 77.5% overall accuracy. CONCLUSIONS: Overall, increased DNA methylation of SRD5A2 and CYP11A1 related to androgen biosynthesis functions may play a role in BCR after patients' RP. The correlation between aberrant cfDNA methylation and detectable PSA in post-RP further suggests their utility as predictive markers for PCa recurrence. .

Colony-stimulating factor 1 potentiates lung cancer bone metastasis.

Colony-stimulating factor 1 (CSF1) is essential for osteoclastogenesis that mediates osteolysis in metastatic tumors. Patients with lung cancer have increased CSF1 in serum and high levels are associated with poor survival. Adenocarcinomas metastasize rapidly and many patients suffer from bone metastasis. Lung cancer stem-like cells sustain tumor growth and potentiate metastasis. The purpose of this study was to determine the role of CSF1 in lung cancer bone metastasis and whether inhibition of CSF1 ameliorates the disease. Human lung adenocarcinoma A549 cells were examined in vitro for CSF1/CSF1R. A549-luc cells were injected intracardiac in NOD/SCID mice and metastasis was assessed. To determine the effect of CSF1 knockdown (KD) in A549 cells on bone metastasis, cells were stably transfected with a retroviral vector containing short-hairpin CSF1 (KD) or empty vector (CT). Results showed that A549 cells express CSF1/CSF1R; CSF1 increased their proliferation and invasion, whereas soluble CSF1R inhibited invasion. Mice injected with A549-luc cells showed osteolytic bone lesions 3.5 weeks after injection and lesions increased over 5 weeks. Tumors recapitulated adenocarcinoma morphology and showed osteoclasts along the tumor/bone interface, trabecular, and cortical bone loss. Analyses of KD cells showed decreased CSF1 protein levels, reduced colony formation in soft agar assay, and decreased fraction of stem-like cells. In CSF1KD mice, the incidence of tumor metastasis was similar to controls, although fewer CSF1KD mice had metastasis in both hind limbs. KD tumors showed reduced CSF1 expression, Ki-67+ cells, and osteoclasts. Importantly, there was a low incidence of large tumors >0.1 mm(2) in CSF1KD mice compared with control mice (10% vs 62.5%). This study established a lung osteolytic bone metastasis model that resembles human disease and suggests that CSF1 is a key determinant of cancer stem cell survival and tumor growth. Results may lead to novel strategies to inhibit CSF1 in lung cancer and improve management of bone metastasis.

Crebbp haploinsufficiency in mice alters the bone marrow microenvironment, leading to loss of stem cells and excessive myelopoiesis.

CREB-binding protein (CREBBP) is important for the cell-autonomous regulation of hematopoiesis, including the stem cell compartment. In the present study, we show that CREBBP plays an equally pivotal role in microenvironment-mediated regulation of hematopoiesis. We found that the BM microenvironment of Crebbp(+/-) mice was unable to properly maintain the immature stem cell and progenitor cell pools. Instead, it stimulates myeloid differentiation, which progresses into a myeloproliferation phenotype. Alterations in the BM microenvironment resulting from haploinsufficiency of Crebbp included a marked decrease in trabecular bone that was predominantly caused by increased osteoclastogenesis. Although CFU-fibroblast (CFU-F) and total osteoblast numbers were decreased, the bone formation rate was similar to that found in wild-type mice. At the molecular level, we found that the known hematopoietic modulators matrix metallopeptidase-9 (MMP9) and kit ligand (KITL) were decreased with heterozygous levels of Crebbp. Lastly, potentially important regulatory proteins, endothelial cell adhesion molecule 1 (ESAM1) and cadherin 5 (CDH5), were increased on Crebbp(+/-) endothelial cells. Our findings reveal that a full dose of Crebbp is essential in the BM microenvironment to maintain proper hematopoiesis and to prevent excessive myeloproliferation.

Novel mechanism of regulation of the DNA repair enzyme OGG1 in tuberin-deficient cells.

Tuberin (protein encodes by tuberous sclerosis complex 2, Tsc2) deficiency is associated with the decrease in the DNA repair enzyme 8-oxoG-DNA glycosylase (OGG1) in tumour kidney of tuberous sclerosis complex (TSC) patients. The purpose of this study was to elucidate the mechanisms by which tuberin regulates OGG1. The partial deficiency in tuberin expression that occurs in the renal proximal tubular cells and kidney cortex of the Eker rat is associated with decreased activator protein 4 (AP4) and OGG1 expression. A complete deficiency in tuberin is associated with loss of AP4 and OGG1 expression in kidney tumour from Eker rats and the accumulation of significant levels of 8-oxo-deoxyguanosine. Knockdown of tuberin expression in human renal epithelial cells (HEK293) with small interfering RNA (siRNA) also resulted in a marked decrease in the expression of AP4 and OGG1. In contrast, overexpression of tuberin in HEK293 cells increased the expression of AP4 and OGG1 proteins. Downregulation of AP4 expression using siRNA resulted in a significant decrease in the protein expression of OGG1. Immunoprecipitation studies show that AP4 is associated with tuberin in cells. Gel shift analysis and chromatin immunoprecipitation identified the transcription factor AP4 as a positive regulator of the OGG1 promoter. AP4 DNA-binding activity is significantly reduced in Tsc2(-/-) as compared with Tsc2(+/+) cells. Transcriptional activity of the OGG1 promoter is also decreased in tuberin-null cells compared with wild-type cells. These data indicate a novel role for tuberin in the regulation of OGG1 through the transcription factor AP4. This regulation may be important in the pathogenesis of kidney tumours in patients with TSC disease.

Diabetic eNOS knockout mice develop distinct macro- and microvascular complications.

Functional consequences of impaired endothelial nitric oxide synthase (eNOS) activity causing organ-specific abnormalities on a diabetic setting are not completely understood. In this study, we extensively characterized a diabetic mouse model (lepr(db/db)) in which eNOS expression is genetically disrupted (eNOS-/-). The eNOS-/-/ lepr(db/db) double-knockout (DKO) mice developed obesity, hyperglycemia, hyperinsulinemia and hypertension. Analysis of tissues from DKO mice showed large islets in the pancreas and fat droplets in hepatocytes. Interestingly, the aorta was normal and atherogenic lesions were not observed. Abnormalities in the aorta including poor re-endothelialization and increased medial wall thickness were evident only in response to deliberate injury. In contrast, significant glomerular capillary damage in the kidney was identified, with DKO mice demonstrating a robust diabetic nephropathy similar to human disease. The vascular and renal impairments in DKO mice were pronounced despite lower fasting plasma glucose levels compared to lepr(db/db) mice, indicating that eNOS is a critical determinant of hyperglycemia-induced organ-specific complications and their severity in diabetes. Results provide the first evidence that absence of eNOS in diabetes has a greater deleterious effect on the renal microvasculature than on the larger aortic vessel. The DKO model may suggest novel therapeutic strategies to prevent both vascular and renal complications of diabetes.

Injured sensory neuron-derived CSF1 induces microglial proliferation and DAP12-dependent pain.

Although microglia have been implicated in nerve injury-induced neuropathic pain, the manner by which injured sensory neurons engage microglia remains unclear. We found that peripheral nerve injury induced de novo expression of colony-stimulating factor 1 (CSF1) in injured sensory neurons. CSF1 was transported to the spinal cord, where it targeted the microglial CSF1 receptor (CSF1R). Cre-mediated sensory neuron deletion of Csf1 completely prevented nerve injury-induced mechanical hypersensitivity and reduced microglial activation and proliferation. In contrast, intrathecal injection of CSF1 induced mechanical hypersensitivity and microglial proliferation. Nerve injury also upregulated CSF1 in motoneurons, where it was required for ventral horn microglial activation and proliferation. Downstream of CSF1R, we found that the microglial membrane adaptor protein DAP12 was required for both nerve injury- and intrathecal CSF1-induced upregulation of pain-related microglial genes and the ensuing pain, but not for microglial proliferation. Thus, both CSF1 and DAP12 are potential targets for the pharmacotherapy of neuropathic pain.

Key diagnostic features of granulomatous interstitial nephritis due to Encephalitozoon cuniculi in a lung transplant recipient.

Microsporidia are increasingly recognized as opportunistic pathogens in immunocompromised organ transplant recipients (OTR). Disseminated infection due to Encephalitozoon sp. is reported mainly in human immunodeficiency virus (HIV)-positive patients and rarely in HIV-negative OTR. The clinical spectrum ranges from keratoconjunctivitis, to pneumonitis, to acute kidney injury. The kidney is a common site for disseminated infection; however, specialized techniques are required for definitive diagnosis. We report the first case of disseminated Encephalitozoon cuniculi infection in an HIV-negative lung transplant recipient diagnosed on renal biopsy. Five months after transplant, he presented with fever and a lung infiltrate and developed acute kidney injury. Renal biopsy showed granulomatous interstitial nephritis with gram-positive rod-shaped organisms with a "belt-like stripe" in tubular epithelial cells. Electron microscopy, polymerase chain reaction, and mammalian cell cultures of the urine sediment confirmed E. cuniculi infection. Retrospective review of a previous lung biopsy showed similar organisms. On the basis of electron microscopy findings, the patient was treated with albendazole, and immunosuppressive therapy was reduced. However, the patient expired due to Aspergillus pneumonia and disseminated E. cuniculi infection. Microsporidia should be considered in cases of fever of unknown origin and/or multiorgan infection in HIV-negative OTR when other causes have been excluded, as successful treatment requires early detection.