Publications by authors named "Nancy Freitag"

Carbon catabolite repression (CCR) is a widely conserved regulatory process that ensures enzymes and transporters of less-preferred carbohydrates are transcriptionally repressed in the presence of a preferred carbohydrate. This phenomenon can be regulated via a CcpA-dependent or CcpA-independent mechanism. The CcpA-independent mechanism typically requires a transcriptional regulator harboring a phosphotransferase regulatory domain (PRD) that interacts with phosphoransferase ystem (PTS) components.

View Article and Find Full Text PDF

Adverse intrauterine conditions may cause fetal growth restriction (FGR), a pregnancy complication frequently linked to perinatal morbidity and mortality. Although many studies have focused on FGR, the pathophysiological processes underlying this disorder are complex and incompletely understood. We have recently determined that galectin-3 (gal-3), a β-galactoside-binding protein, regulates pregnancy-associated processes, including uterine receptibility, maternal vascular adaptation and placentation.

View Article and Find Full Text PDF
Article Synopsis
  • Abnormal placental blood vessel development caused by high levels of anti-angiogenic factors like sFLT1 is associated with preeclampsia, a serious condition that affects pregnant women and their babies after 20 weeks.
  • Previous studies on mice showed that increased hsFLT1 leads to reduced placental function and symptoms similar to preeclampsia.
  • This research found elevated levels of the protein galectin-1 in specific areas of the placenta in hsFLT1 mice, suggesting that the galectin-glycan network may help counteract the harmful effects of anti-angiogenic factors during pregnancy.
View Article and Find Full Text PDF

is a foodborne bacterial pathogen that causes listeriosis. Positive regulatory factor A (PrfA) is a pleiotropic master activator of virulence genes of that becomes active upon the entry of the bacterium into the cytosol of infected cells. can survive and multiply at low temperatures; this is accomplished through the maintenance of appropriate membrane fluidity via branched-chain fatty acid (BCFA) synthesis.

View Article and Find Full Text PDF

Unlabelled: Pathogenic bacteria rely on secreted virulence factors to cause disease in susceptible hosts. However, in Gram-positive bacteria, the mechanisms underlying secreted protein activation and regulation post-membrane translocation remain largely unknown. Using proteomics, we identified several proteins that are dependent on the secreted chaperone PrsA2.

View Article and Find Full Text PDF
Article Synopsis
  • The text discusses a specific bacterium that can thrive in stressful conditions and switch between being a soil bacterium and a pathogen in mammals.
  • It emphasizes the importance of two-component signaling systems (TCSs), which help the bacterium sense environmental changes and respond by activating certain genes.
  • The review highlights the challenges in identifying the exact stimuli that trigger TCS responses and points to ongoing research into the gene networks linked to these systems, which may reveal useful insights into stress resistance and pathogenesis.
View Article and Find Full Text PDF

Vertically transmitted infections are a significant cause of fetal morbidity and mortality during pregnancy and pose substantial risks to fetal development. These infections are primarily transmitted to the fetus through two routes: (1) direct invasion and crossing the placenta which separates maternal and fetal circulation, or (2) ascending the maternal genitourinary tact and entering the uterus. Only two bacterial species are commonly found to cross the placenta and infect the fetus: and subsp.

View Article and Find Full Text PDF
Article Synopsis
  • Placental abnormalities can lead to issues like preeclampsia (PE), impacting both the mother's health and fetal growth.
  • Galectin-1 (gal-1) is a crucial protein at the maternal-fetal interface that helps regulate pregnancy adaptations and placental development.
  • A deficiency of gal-1, especially from the mother, increases the risk of PE and disrupts normal placental function, suggesting that problems with gal-1 signaling might contribute to pregnancy complications and maternal cardiovascular issues.
View Article and Find Full Text PDF

The soil-dwelling bacterium Listeria monocytogenes survives a multitude of conditions when residing in the outside environment and as a pathogen within host cells. Key to survival within the infected mammalian host is the expression of bacterial gene products necessary for nutrient acquisition. Similar to many bacteria, L.

View Article and Find Full Text PDF

Listeria monocytogenes is a ubiquitous opportunistic foodborne pathogen capable of survival in various adverse environmental conditions. Pathogenesis of L. monocytogenes is tightly controlled by a complex regulatory network of transcriptional regulators that are necessary for survival and adaptations to harsh environmental conditions both inside and outside host cells.

View Article and Find Full Text PDF

Listeria monocytogenes (Lm) is a widespread environmental Gram-positive bacterium that can transition into a pathogen following ingestion by a susceptible host. To cross host barriers and establish infection, Lm is dependent upon the regulated secretion and activity of many proteins including PrsA2, a peptidyl-prolyl cis-trans isomerase with foldase activity. PrsA2 contributes to the stability and activity of a number of secreted virulence factors that are required for Lm invasion, replication, and cell-to-cell spread within the infected host.

View Article and Find Full Text PDF

Galectin-1 (gal-1), a member of a family of evolutionarily conserved glycan-binding proteins, is differentially expressed at the feto-maternal interface and appears to be functionally polyvalent, with a wide range of biological activities. However, the contributions of maternal and/or feto-placental gal-1 to the signaling networks promoting a healthy pregnancy are still being elucidated. This chapter discusses the methods commonly employed to study the maternal or feto-placental contribution of gal-1 during pregnancy in mice.

View Article and Find Full Text PDF

Problem: Proper placental development is pivotal to ensure healthy pregnancy outcomes. Among the multiple cellular mechanisms involved in the orchestration of this process, little is known on the role of alternative splicing events in the modulation of trophoblast cell biology. Here, we evaluated the expression of the alternative splicing regulator Rbfox2 in the pre- and post-placentation period in mouse pregnancies in both healthy and pathological settings.

View Article and Find Full Text PDF

Liver fibrosis results from many chronic injuries and may often progress to cirrhosis and hepatocellular carcinoma (HCC). In fact, up to 90% of HCC arise in a cirrhotic liver. Conversely, stress is implicated in liver damage, worsening disease outcome.

View Article and Find Full Text PDF

Galectin (gal)-1, -3, and -9 are members of a family of glycan binding proteins that mediate complex interactions between decidual, inflammatory and trophoblast cells modulating several processes during gestation, control of the maternal immune system, and parturition. Their immunomodulatory role in preterm birth and postnatal expression in preterm infants is unknown. We performed a single center prospective study of 170 preterm infants with a gestational age below 35 weeks.

View Article and Find Full Text PDF

Galectin 3 is a multifunctional lectin implicated in cellular proliferation, differentiation, adhesion, and apoptosis. This lectin is broadly expressed in testicular somatic cells and germ cells, and is upregulated during testicular development. Since the role of galectin 3 in testicular function remains elusive, we aimed to characterize the role of galectin 3 in testicular physiology.

View Article and Find Full Text PDF

The Gram-positive bacterium survives in environments ranging from the soil to the cytosol of infected host cells. Key to intracellular survival is the activation of PrfA, a transcriptional regulator that is required for the expression of multiple bacterial virulence factors. Mutations that constitutively activate ( mutations) result in high-level expression of multiple bacterial virulence factors as well as the physiological adaptation of for optimal replication within host cells.

View Article and Find Full Text PDF
Article Synopsis
  • Placental hypoperfusion and hypoxia are major factors leading to fetal complications like growth restriction and preeclampsia, making it essential to develop biomarkers to study these issues in mice.
  • This study aimed to noninvasively measure placental oxygen levels using fluorine magnetic resonance imaging (F MRI) in a specific mouse model (Lgals1 deficient) associated with preeclampsia, with the expectation that oxygen levels would be lower in these knockout mice.
  • Results indicated that while oxygen levels did increase with higher oxygen content in the air, the decrease in oxygenation observed in knockout mice was only significant at the lowest oxygen level (30%) and reinforced that F MRI can effectively assess placental oxygenation in these
View Article and Find Full Text PDF
Article Synopsis
  • The text discusses a Gram-positive bacterium that can cause severe infections in pregnant women, leading to serious outcomes like abortion and stillbirth.
  • A specific strain, 07PF0776, is noted for its increased targeting of cardiac tissues, which is linked to variations in a surface protein called internalin B (InlB) that helps the bacteria invade host cells.
  • Experiments on pregnant mice show that the 07PF0776 strain significantly enhances the transmission of the bacterium to both placentas and fetuses, highlighting the role of surface InlB in this process.
View Article and Find Full Text PDF

Immune cells [e. g., dendritic cells (DC) and natural killer (NK) cells] are critical players during the pre-placentation stage for successful mammalian pregnancy.

View Article and Find Full Text PDF

Fetal growth restriction (FGR) is the most common pregnancy complication in developed countries. Pregnancies affected by FGR, frequently concur with complications and high risk of neonatal morbidity and mortality. To date, no approved treatment is available for pregnant women affected with FGR.

View Article and Find Full Text PDF

Problem: From conception, a delicate regulation of galectins, a family of carbohydrate-binding proteins, is established to ensure maternal immune tolerance in pregnancy. Though galectin-3 (gal-3), the only chimera-type galectin, is abundantly expressed at the feto-maternal interface; the physiological role of this lectin during pregnancy remains to be fully elucidated and requires further investigation.

Method Of Study: In this study, we analyzed serum gal-3 levels during the course of healthy gestation.

View Article and Find Full Text PDF

Bacterial pathogens often employ RNA regulatory elements located in the 5' untranslated regions (UTRs) to control gene expression. Using a comparative structural analysis, we examine the structure of 5' UTRs at a global scale in the pathogenic bacterium Listeria monocytogenes under different conditions. In addition to discovering an RNA thermoswitch and detecting simultaneous interaction of ribosomes and small RNAs with mRNA, we identify structural changes in the 5' UTR of an mRNA encoding the post-translocation chaperone PrsA2 during infection conditions.

View Article and Find Full Text PDF

Whereas obligate human and animal bacterial pathogens may be able to depend upon the warmth and relative stability of their chosen replication niche, environmental bacteria such as that harbor the ability to replicate both within animal cells and in the outside environment must maintain the capability to manage life under a variety of disparate conditions. Bacterial life in the outside environment requires adaptation to wide ranges of temperature, available nutrients, and physical stresses such as changes in pH and osmolarity as well as desiccation. Following ingestion by a susceptible animal host, the bacterium must adapt to similar changes during transit through the gastrointestinal tract and overcome a variety of barriers associated with host innate immune responses.

View Article and Find Full Text PDF