ABSTRACT
Intake of hemoglobin by the hemoglobin-haptoglobin receptor CD163 leads to a distinct alternative non-foam cell antiinflammatory macrophage phenotype that was previously considered atheroprotective. Here, we reveal an unexpected but important pathogenic role for these macrophages in atherosclerosis. Using human atherosclerotic samples, cultured cells, and a mouse model of advanced atherosclerosis, we investigated the role of intraplaque hemorrhage on macrophage function with respect to angiogenesis, vascular permeability, inflammation, and plaque progression. In human atherosclerotic lesions, CD163+ macrophages were associated with plaque progression, microvascularity, and a high level of HIF1α and VEGF-A expression. We observed irregular vascular endothelial cadherin in intraplaque microvessels surrounded by CD163+ macrophages. Within these cells, activation of HIF1α via inhibition of prolyl hydroxylases promoted VEGF-mediated increases in intraplaque angiogenesis, vascular permeability, and inflammatory cell recruitment. CD163+ macrophages increased intraplaque endothelial VCAM expression and plaque inflammation. Subjects with homozygous minor alleles of the SNP rs7136716 had elevated microvessel density, increased expression of CD163 in ruptured coronary plaques, and a higher risk of myocardial infarction and coronary heart disease in population cohorts. Thus, our findings highlight a nonlipid-driven mechanism by which alternative macrophages promote plaque angiogenesis, leakiness, inflammation, and progression via the CD163/HIF1α/VEGF-A pathway.
Subject(s)
Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , Atherosclerosis/metabolism , Inflammation/metabolism , Macrophages/cytology , Neovascularization, Pathologic , Receptors, Cell Surface/metabolism , Adult , Animals , Antigens, CD/genetics , Antigens, Differentiation, Myelomonocytic/genetics , Coronary Disease/metabolism , Coronary Vessels/metabolism , Disease Progression , Female , Hemoglobins/metabolism , Humans , Macrophages/metabolism , Male , Mice , Mice, Inbred C57BL , Middle Aged , Myocardial Infarction/metabolism , Oxidative Stress , Permeability , Phenotype , Polymorphism, Single Nucleotide , Receptors, Cell Surface/genetics , Signal TransductionABSTRACT
Bacteroides fragilis is the most frequent opportunistic pathogen isolated from anaerobic infections. However, there is a paucity of information regarding the genetic and molecular aspects of gene expression of its virulence factors during extra-intestinal infections. A potential virulence factor that has received little attention is the ability of B. fragilis to produce hemolysins. In this study, an implanted perforated table tennis "ping-pong" ball was used as an intra-abdominal artificial abscess model in the rat. This procedure provided sufficient infected exudate for gene expression studies in vivo. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to quantify the relative expression of hlyA, hlyB, hlyC, hlyD, hlyE, hlyF, hlyG, and hlyIII mRNAs. The hlyA mRNA was induced approximately sixfold after 4 days postinfection compared with the mRNA levels in the inoculum culture prior to infection. The hlyB mRNA increased approximately sixfold after 4 days and 12-fold after 8 days postinfection. Expression of hlyC mRNA increased sixfold after 1 day, 45-fold after 4 days, and 16-fold after 8 days postinfection, respectively. The hlyD and hlyE mRNAs were induced approximately 40-fold and 30-fold, respectively, after 4-days postinfection. The hlyF expression increased approximately threefold after 4-days postinfection. hlyG was induced approximately fivefold after 4 and 8 days postinfection. The hlyIII mRNA levels had a steady increase of approximately four-, eight-, and 12-fold following 1, 4, and 8 days postinfection, respectively. These findings suggest that B. fragilis hemolysins are induced and differentially regulated in vivo. Both parent and hlyBA mutant strains reached levels of approximately 3-8 × 10(9) cfu/mL after 1 day postinfection. However, the hlyBA mutant strain lost 2 logs in viable cell counts compared with the parent strain after 8 days postinfection. This is the first study showing HlyBA is a virulence factor which plays a role in B. fragilis survival in an intra-abdominal abscess model.
Subject(s)
Bacterial Proteins/metabolism , Bacteroides fragilis/genetics , Carrier Proteins/metabolism , Hemolysin Proteins/metabolism , Intraabdominal Infections/microbiology , Abdominal Abscess/microbiology , Abdominal Abscess/pathology , Animals , Bacterial Load , Bacterial Proteins/genetics , Bacteroides fragilis/pathogenicity , Carrier Proteins/genetics , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Hemolysin Proteins/genetics , Intraabdominal Infections/pathology , Male , Microbial Viability , RNA, Bacterial/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Real-Time Polymerase Chain Reaction , Transcription, GeneticABSTRACT
Derangement in pulmonary surfactant or its components and alveolar collapse are common findings in idiopathic pulmonary fibrosis (IPF). Surfactant proteins play important roles in innate host defense and normal function of the lung. We examined associations between IPF and genetic polymorphic variants of surfactant proteins, SP-A1, SP-A2, SP-B, SP-C, and SP-D. One SP-A1 (6A(4)) allele and single nucleotide polymorphisms (SNPs) that characterize the 6A(4) allele, and one SP-B (B1580_C) were found with higher frequency ( P
Subject(s)
Genetic Predisposition to Disease , Pulmonary Fibrosis/genetics , Pulmonary Surfactant-Associated Protein A/genetics , Pulmonary Surfactant-Associated Protein B/genetics , Adult , Female , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide , Pulmonary Fibrosis/physiopathology , Pulmonary Surfactant-Associated Protein A/chemistry , Pulmonary Surfactant-Associated Protein A/metabolism , Pulmonary Surfactant-Associated Protein C/genetics , Pulmonary Surfactant-Associated Protein D/genetics , SpectrophotometryABSTRACT
HPV-40 is a rare HPV type that has been detected only in genital mucosal tissues. This HPV type is very closely related to HPV-7, which has a predominantly cutaneous tissue tropism. We have shown, previously, that an isolate of HPV-40 (described here as HPV-40(Hershey) or HPV-40(H)) productively infected genital tissues. In this study, HPV-40(H) was tested for productive infection of cutaneous tissue. Fetal hand skin fragments were incubated with infectious HPV-40(H) and implanted subrenally into athymic mice. After 120 days, xenografts showed morphological changes consistent with HPV-40(H) infection and were HPV-40 DNA in situ positive and capsid antigen positive. The results demonstrated that hand skin can support HPV-40(H) infection thereby indicating that this viral type has the capacity to infect both genital mucosal and cutaneous tissues.
