Tissue macrophages play an important role in all stages of pregnancy, including uterine stromal remodeling (decidualization) before embryo implantation, parturition, and post-partum uterine involution. The activation state and function of utero-placental macrophages are largely dependent on the local tissue microenvironment. Thus, macrophages are involved in a variety of activities such as regulation of immune cell activities, placental cell invasion, angiogenesis, and tissue remodeling. Disruption of the uterine microenvironment, particularly during the early stages of pregnancy (decidualization, implantation, and placentation) can have profound effects on macrophage activity and subsequently impact pregnancy outcome. In this review, we will provide an overview of the temporal and spatial regulation of utero-placental macrophage activation during normal pregnancy in human beings and rodents with a focus on more recent findings. We will also discuss the role of M1/M2 dysregulation within the intrauterine environment during adverse pregnancy outcomes.

Ureaplasma parvum, an opportunistic pathogen of the human urogenital tract, has been implicated in contributing to chorioamnionitis, fetal morbidity, and fetal mortality. It has been proposed that the host genetic background is a critical factor in adverse pregnancy outcome as sequela to U. parvum intra-amniotic infection. To test this hypothesis we assessed the impact of intrauterine U. parvum infection in the prototypical TH1/M1 C57BL/6 and TH2/M2 BALB/c mouse strain. Sterile medium or U. parvum was inoculated into each uterine horn and animals were evaluated for intra-amniotic infection, fetal infection, chorioamnionitis and fetal pathology at 72 hours post-inoculation. Disease outcome was assessed by microbial culture, in situ detection of U. parvum in fetal and utero-placental tissues, grading of chorioamnionitis, and placental gene expression of IL-1α, IL-1β, IL-6, TNF-α, S100A8, and S100A9. Placental infection and colonization rates were equivalent in both strains. The in situ distribution of U. parvum in placental tissues was also similar. However, a significantly greater proportion of BALB/c fetuses were infected (P<0.02). C57BL/6 infected animals predominantly exhibited mild to moderate chorioamnionitis (P<0.0001), and a significant reduction in placental expression of IL-1α, IL-1β, IL-6, TNF-α, S100A8, and S100A9 compared to sham controls (P<0.02). Conversely, severe protracted chorioamnionitis with cellular necrosis was the predominant lesion phenotype in BALB/c mice, which also exhibited a significant increase in placental expression of IL-1α, IL-1β, IL-6, TNF-α, S100A8, and S100A9 (P<0.01). Fetal pathology in BALB/c was multi-organ and included brain, lung, heart, liver, and intestine, whereas fetal pathology in C57BL/6 was only detected in the liver and intestines. These results confirm that the host genetic background is a major determinant in ureaplasmal induced chorioamnionitis with fetal infection and fetal inflammatory response.

A suicide plasmid, pExp1-ctpA::tetM-recAec, employing recA from Escherichia coli and tetM as a selection marker, was used to generate ctpA knockout mutants in Mycoplasma mycoides subsp. capri through targeted gene disruption. Inclusion of E. coli recA greatly enhanced both the consistency and the recovery of mutants generated by homologous recombination.Mycoplasmas have the smallest genomes of free-living organisms (15,23,32), yet the range of infections that they cause and their host species are among the most diverse in the microbial world (15). A major limitation in unraveling the virulence factors of these microbes is the paucity of tools for genetic manipulation (18, 30). Transposon-based mutagenesis (3, 4, 11, 12, 16-19, 34, 35), which has been employed to define the minimally essential genes for sustaining life and also to generate mutants of interest (17,19), is the most widely used approach to genetic manipulation of Mollicutes. Replicating plasmids based on oriC (2-5, 9, 10, 18, 20, 24) have been used with limited success for heterologous gene expression as well as for targeted gene disruption by single-crossover recombination for a number of mycoplasma species (2-4, 9, 10, 20, 24, 27). However, many passages are required before they are integrated into the chromosome (5, 27), and mutants may not be stable.Although classical double-crossover homologous recombination using a suicide plasmid is potentially a powerful technique, recombination by double-crossover has been reported only for Mycoplasma genitalium, and even then it occurs at a very low frequency (1,7,8). We report here the development of a suicide plasmid for targeted homologous recombination in M. mycoides subsp. capri that incorporates recA from Escherichia coli and tetM as a selection marker and that results in consistent recovery of targeted stable double-crossover mutants. As a target gene for disruption, we chose the M. mycoides subsp. capri ctpA gene (MMCAP2_0241), which confers a proteolytic phenotype that

F344 rats chronically infected with Ureaplasma parvum develop two distinct profiles: asymptomatic urinary tract infection (UTI) and UTI complicated by struvite urolithiasis. To identify factors that affect disease outcome, we characterized the temporal host immune response during infection by histopathologic analysis and in situ localization of U. parvum. We also used differential quantitative proteomics to identify distinguishing host cellular responses associated with complicated UTI. In animals in which microbial colonization was limited to the mucosal surface, inflammation was indistinguishable from that which occurred in shaminoculated controls, and the inflammation resolved by 72 h postinoculation (p.i.) in both groups. However, inflammation persisted in animals with microbial colonization that extended into the deeper layers of the submucosa. Proteome profiling showed that bladder tissues from animals with complicated UTIs had significant increases (P < 0.01) in proteins involved in apoptosis, oxidative stress, and inflammation. Animals with complicated UTIs (2 weeks p.i.) had the highest concentrations of the proinflammatory protein S100A8 (P < 0.005) in bladder tissues, and the levels of S100A8 positively correlated with those of proinflammatory cytokines GRO/KC (P < 0.003) and interleukin-1␣ (P < 0.03) in urine. The bladder uroepithelium was a prominent cell source of S100A8-S100A9 in animals with complicated UTIs (2 weeks p.i.), which was not detected in animals with asymptomatic UTIs (2 weeks p.i.) or in any bladder tissues harvested at earlier p.i. time points. Based on these results, we surmise that invasive colonization of the bladder triggers chronic inflammation and immune dysregulation, which may be critical to struvite formation.Struvite or infection stones form as a result of complicated urinary tract infections (UTI) caused by urease-producing bacteria such as Proteus, Klebsiella, Serratia, and Ureaplasma species (5,8,9,17). Bacterial urease breaks down urea into ammonia, resulting in urine's becoming supersaturated with ammonia. When this occurs, the urine pH rises and the solubility of magnesium ammonium phosphate decreases, leading to crystal deposition and stone formation. Infection is always an underlying cause of struvite urolithiasis (5, 9). Therefore, it is not surprising that known predisposing factors such as renal tubular acidosis, neurogenic bladder, urinary tract obstructions, and chronic use of indwelling catheters (5, 9) are related to elements that increase patient susceptibility to UTI. Although infections usually induce an inflammatory response in the host, to our knowledge, the role of the host immune response as a potential predisposing factor in struvite urolithiasis has not been evaluated or considered to be important in disease pathogenesis. We present data suggesting that the host immune response plays a critical role in the development of struvite stones and that the proinflammatory protein S100A8-S100A9 may play a critical role in the chronic inflammation and immune...