Publications by authors named "Sean Merillat"

Article Synopsis
  • - Invasive bacterial infections, like those caused by Group B streptococci (GBS), significantly raise risks for negative pregnancy outcomes such as preterm birth and stillbirth due to their ability to infect the maternal-fetal area.
  • - A research study using a nonhuman primate model revealed that GBS expressing the enzyme hyaluronidase (HylB) led to consistent bacterial invasion into the amniotic cavity, fetal infection, and preterm labor.
  • - The findings suggest that HylB allows GBS to evade immune responses and cause preterm labor by increasing certain inflammatory markers, highlighting the need for better strategies to prevent these issues during pregnancy.
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Leukocyte activation within the chorioamniotic membranes is strongly associated with inflammation and preterm labor (PTL). We hypothesized that prophylaxis with a broad-spectrum chemokine inhibitor (BSCI) would downregulate the inflammatory microenvironment induced by Group B Streptococcus (GBS, ) to suppress PTL and microbial invasion of the amniotic cavity (MIAC). To correlate BSCI administration with PTL and MIAC, we used a unique chronically catheterized non-human primate model of Group B Streptococcus (GBS)-induced PTL.

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Although certain microbial lipids are toxins, the structural features important for cytotoxicity remain unknown. Increased functional understanding is essential for developing therapeutics against toxic microbial lipids. Group B Streptococci (GBS) are bacteria associated with preterm births, stillbirths, and severe infections in neonates and adults.

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Thirteen percent of pregnancies result in preterm birth or stillbirth, accounting for fifteen million preterm births and three and a half million deaths annually. A significant cause of these adverse pregnancy outcomes is in utero infection by vaginal microorganisms. To establish an in utero infection, vaginal microbes enter the uterus by ascending infection; however, the mechanisms by which this occurs are unknown.

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Article Synopsis
  • - The study investigates the impact of fetal inflammatory response syndrome, marked by elevated interleukin-6, on gene networks related to fetal heart development in a nonhuman primate model.
  • - Researchers extracted and analyzed fetal cardiac tissue from infected and control pigtail macaques, finding significant inflammation and notable changes in gene expression linked to heart development in inflamed hearts.
  • - Results revealed that inflammation from intraamniotic infection leads to elevated cytokine levels and disrupted genetic programming, contributing to potential long-term cardiovascular health issues in affected fetuses.
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Zika virus (ZIKV) is a flavivirus with teratogenic effects on fetal brain, but the spectrum of ZIKV-induced brain injury is unknown, particularly when ultrasound imaging is normal. In a pregnant pigtail macaque (Macaca nemestrina) model of ZIKV infection, we demonstrate that ZIKV-induced injury to fetal brain is substantial, even in the absence of microcephaly, and may be challenging to detect in a clinical setting. A common and subtle injury pattern was identified, including (i) periventricular T2-hyperintense foci and loss of fetal noncortical brain volume, (ii) injury to the ependymal epithelium with underlying gliosis and (iii) loss of late fetal neuronal progenitor cells in the subventricular zone (temporal cortex) and subgranular zone (dentate gyrus, hippocampus) with dysmorphic granule neuron patterning.

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Group B streptococci (GBS) are encapsulated, β-hemolytic bacteria that are a common cause of infections in human newborns and certain adults. Two factors important for GBS virulence are the sialic acid capsular polysaccharide that promotes immune evasion and the hemolytic pigment that induces host cell cytotoxcity. These virulence factors are often oppositely regulated by the CovR/CovS two-component system.

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Group B streptococci (GBS) are Gram-positive bacteria that are a leading cause of neonatal infections. Most invasive isolates are β-hemolytic, and hemolytic activity is critical for GBS virulence. Although nonhemolytic GBS strains are occasionally isolated, they are often thought to be virulence attenuated.

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Huntington's disease (HD) is caused by a CAG repeat expansion that encodes a polyglutamine (polyQ) expansion in the HD disease protein, huntingtin (HTT). PolyQ expansion promotes misfolding and aggregation of mutant HTT (mHTT) within neurons. The cellular pathways, including ubiquitin-dependent processes, by which mHTT is regulated remain incompletely understood.

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Background: Group B Streptococcus (GBS) or Streptococcus agalactiae are β-hemolytic gram-positive bacteria that colonize the lower genital tracts of women and are frequently associated with infections during pregnancy. Innate immune defenses are critical for controlling GBS dissemination and systemic infection. Mast cells are resident sentinel cells that come into contact with pathogens early during colonization and infection.

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Preterm birth is a leading cause of neonatal morbidity and mortality. Although microbial invasion of the amniotic cavity (MIAC) is associated with the majority of early preterm births, the temporal events that occur during MIAC and preterm labor are not known. Group B Streptococci (GBS) are β-hemolytic, gram-positive bacteria, which commonly colonize the vagina but have been recovered from the amniotic fluid in preterm birth cases.

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Article Synopsis
  • Scientists studied how the Zika virus affected a baby monkey's brain when its mom was infected.
  • The baby developed brain damage in specific areas within 10 days after the infection.
  • This study helps researchers better understand Zika's effects on the brain, which can help find better treatments.
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Unlabelled: Preterm birth increases the risk of adverse birth outcomes and is the leading cause of neonatal mortality. A significant cause of preterm birth is in utero infection with vaginal microorganisms. These vaginal microorganisms are often recovered from the amniotic fluid of preterm birth cases.

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UBE2W ubiquitinates N termini of proteins rather than internal lysine residues, showing a preference for substrates with intrinsically disordered N termini. The in vivo functions of this intriguing E2, however, remain unknown. We generated Ube2w germ line KO mice that proved to be susceptible to early postnatal lethality without obvious developmental abnormalities.

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Accumulation of mutant polyglutamine proteins in intraneuronal inclusions is a hallmark of polyglutamine diseases. Impairment of protein clearance systems and sequestration of clearance-related proteins into inclusions occur in many protein folding diseases, including polyglutamine diseases. The ubiquitin-binding and proteasome adaptor protein UBQLN2 participates in protein homeostasis and localizes to inclusions in various neurodegenerative diseases.

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