Project description:Listeria monocytogenes (Lm) kills up to 60% of infected newborns and adults >60 years of age but is asymptomic is most young adults. Monocytes are central to effective host defense against Lm. We hypothesize that age-dependent, pathway-specific differences in the ability of the monocyte to respond to Lm explain the increased risk of the newborn and older adult to severely suffer or die from Lm infection. To delineate age-dependent differences in innate responses that lead to differential infectious outcome, monocytes were isolated from cord blood (newborn) and peripheral blood (young and older adults) and infected with Lm. RNA was collected to determine age-dependent transcriptomic changes upon infection. Total RNA was isolated from purified human monocytes from 6 adult, 6 cord , 6 older adult blood donors that were infected with wild-type Listeria monocytogenes at a multiplicity of infected (MOI)=5 for 2 and 6 hr.
Project description:Listeria monocytogenes (Lm) kills up to 60% of infected newborns and adults >60 years of age but is asymptomic is most young adults. Monocytes are central to effective host defense against Lm. We hypothesize that age-dependent, pathway-specific differences in the ability of the monocyte to respond to Lm explain the increased risk of the newborn and older adult to severely suffer or die from Lm infection. To delineate age-dependent differences in innate responses that lead to differential infectious outcome, monocytes were isolated from cord blood (newborn) and peripheral blood (young and older adults) and infected with Lm. RNA was collected to determine age-dependent transcriptomic changes upon infection.
Project description:Human neonates and older adults frequently exhibit a reduced capacity to control microbial infections. A variety of mechanisms involving both the innate and adaptive immune systems have been proposed to contribute to these deficiencies. The emergence of RNA sequencing (RNA-seq) as an accurate and quantitative method for examining mRNA levels provides an opportunity to compare transcriptional responses to a stimulus at a global scale in neonates, adults, and older adults. An examination of ex vivo monocyte responses to lipopolysaccharide stimulation or Listeria monocytogenes infection (with cord blood monocytes representing neonatal monocytes) revealed extensive similarities between all three age groups, with only a small number of genes exhibiting statistically significant differences. Using transcription factor motif analyses and RNA-seq data sets from a variety of mouse mutants, the most significant neonatal deficiencies corresponded to genes that require interferon response factor-3 or type 1 interferon signaling for their activation. In older adults, the most striking difference was broad, low-level activation of inflammatory genes prior to stimulation, consistent with prior evidence of a chronic inflammatory state in older adults. These results demonstrate the value of quantitative RNA-seq analyses and the feasibility of cross-species comparisons between well-defined mouse networks and human data sets.
Project description:Expression profiling by microarray was used with a murine listeriosis model to better understand increased susceptibility of preterm neonates to infection. We used DNA microarray to identify genes that were differentially expressed in liver of adult and neonatal Balb/c mice after listeriosis infection. A murine listeriosis model was established. The methods for culturing and counting the Listeria monocytogenes (strain CNL 85/163) had been described in previous publications. The Listeria was injected intraperitoneally using a 1-mL U-100 insulin syringe with a 30 gauge needle. Doses of Listeria monocytogenes used were based on work by our laboratory showing that similar bacterial colony counts were obtained with 4.2 x 10^5 total Listeria per adult mouse and 150 Listeria per gram for 3 to 5 day old neonatal mice. In neonatal mice, great care was taken to void deep intraperitoneal injection towards the viscera, or across the central abdominal vessels. At specified time points, liver was removed upon animal sacrifice and immediately flash frozen in liquid nitrogen and stored at -80 degrees Centigrade. Three adult mice and three neonatal mice were used at each time point.
Project description:Initial transcriptional response of human peripheral monocytes infected with a set of three gram-positive bacterial pathogens (Listeria monocytogenes, Staphylococcus aureus and Streptococcus pneumoniae). Monocytes were isolated from five probands.
Project description:The immune system of SPF mice is dominated by naïve phenotype immune cells, especially within the T cell compartment, and resembles that of neonatal humans (Beura et al., 2016; Reese et al., 2016). Sequential infection of SPF-housed laboratory mice with common experimental pathogens, such as MHV, MCMV, Listeria monocytogenes, LCMV, and influenza A virus (Berton et al., 2022; Reese et al., 2016), or cohousing (CoH) SPF mice with pet store mice carrying multiple pathogenic and commensal bacteria, viruses, and/or fungi (Beura et al., 2016) induces immune system alterations and maturations that more closely resemble the adult human immune system. Such microbial exposure drastically alters the composition and function of the immune system of laboratory mice, which can significantly influence the overall outcome (and survival) to subsequent infection. Here we report CD11b+ CD115+ monocytes sorted from female specific pathogen-free (SPF) C57BL/6N (B6) mice co-housed with petstore mice for 60 days are transcriptionally different than SPF CD11b+ CD115+ monocytes
Project description:DNA damage response kinase ATM regulates the genetic program of lymphocytes with phsiologically induced DNA DSBs. In bone marrow-derived macrophages, related kinase DNAPKcs is also responsible for activating DNA damage responses after infection with Listeria monocytogenes. Here we show that both ATM and DNA-PKcs regulate the genetic program of Listeria monocytogenes-infected macrophages.
Project description:Listeria monocytogenes is a facultative intracellular bacterial pathogen that tightly regulates the activities of various virulence factors during infection. A mutant strain (the plcBΔpro mutant) that has lost the ability to control the activity of a phospholipase C (PC-PLC) is attenuated a hundred fold in mice. This attenuation is not due to a lack of bacterial fitness, but appears to result from a modified host response to infection. The transcriptomic pattern of immunerelated genes in infected macrophages indicated no differential response to wild-type L. monocytogenes vs the plcBΔpro mutant.
Project description:The Galleria mellonella larvae were infected with Listeria monocytogenes and on the 5th of post infection RNA is isolated from infected and non-infected control larvae. RNA samples were processed for miRNA profile in response to L. monocytogenes infection in Galleria mellonella larvae.
Project description:DNA damage response kinase ATM regulates the genetic program of lymphocytes with phsiologically induced DNA DSBs. In bone marrow-derived macrophages, related kinase DNAPKcs is also responsible for activating DNA damage responses after infection with Listeria monocytogenes. Here we show that both ATM and DNA-PKcs regulate the genetic program of Listeria monocytogenes-infected macrophages. Two independent bone marrow-derived macrophage cultures for each genotype (LysMcre/+ and Scid: Atmc/c: LysMcre/+) were infected with Listeria monocytogenes for 24 hrs at an MOI of 5. RNA was isolated using RNeasy (Qiagen). Gene expression profiling was performed using Illumina MouseRef-8 expression microarrays.
