Biology subjects

Crooks, C.

Publications and source records attributed to Crooks, C..

4 recordsLinked to original sources

bioRxiv2025

A nonhuman primate model mirrors human congenital cytomegalovirus infection and reveals a spectrum of vertical transmission outcomes

Congenital cytomegalovirus (cCMV) is the leading infectious cause of birth defects worldwide, yet immune determinants of protection to inform design of a maternal vaccine remain elusive. Here, we characterized the outcome of primary rhesus CMV (RhCMV) infection during pregnancy in an immune competent nonhuman primate (NHP) model. RhCMV DNA was detected in amniotic fluid and/or fetal tissues in six of 12 (50% placental transmission) CMV-naive rhesus macaque dams inoculated intravenously with RhCMV in early second trimester gestation. Widespread tissue dissemination dominated by one of two inoculated RhCMV strains was present in one fetus (8.3% cCMV disease). Placental RhCMV transmission was associated with elevated fetal and maternal plasma TNF-alpha and reduced maternal brain-derived neurotrophic factor and IL-10 levels. CMV exposure during pregnancy had a broad impact on the placenta and fetus even in the absence of congenital infection as evidenced by RhCMV infection at the maternal-fetal interface in all 12 dams, along with significantly reduced placental efficiency and fetal growth metrics compared to gestation-matched control pregnancies. This NHP model recapitulates key aspects of human cCMV and provides new insight into barriers and biomarkers of successful vertical transmission. One sentence summary: The nonhuman primate model mirrors the epidemiology of human congenital CMV (cCMV) after primary infection and reveals its transmission bottlenecks.

immunology↗

bioRxiv2024

One year of gluten free diet impacts gut function and microbiome in celiac disease

BACKGROUND & AIMSCurrently, the main treatment option for coeliac disease (CD) is a gluten free diet (GFD). This observational cohort study investigated the impact of CD and 1 year of GFD on gut function and microbiome. METHODS36 newly diagnosed patients and 36 healthy volunteers (HV) were studied at baseline and at 12 months follow up. Small bowel water content (SBWC), whole gut transit time (WGTT) and colon volumes were measured by MRI. Stool samples DNA was subjected to shotgun metagenomic sequencing. Species level abundances and gene functions, including carbohydrate active enzymes (CAZymes) were determined. RESULTSSBWC was significantly higher in people with CD 157{+/-}15 mL versus HVs 100{+/-}12 mL (p=0.003). WGTT was delayed in people with CD 68{+/-}8 hours versus HVs 41{+/-}5 hours (p=0.002). The differences reduced after 12 months of GFD but not significantly. Wellbeing in the CD group significantly improved after GFD but did not recover to control values. CD faecal microbiota showed high abundance of proteolytic gene functions, associated with Escherichia coli, Enterobacter and Peptostreptococcus. GFD significantly reduced Bifidobacteria and increased Blautia wexerelae. Microbiome composition correlated positively with WGTT, colonic volume and Akkermansia municphilia but negatively with B.wexerelae. Following GFD the reduction in WGTT and colonic volume significantly associated with increased abundance of B.wexerelae. There were also significant alterations in CAZyme profiles, specifically starch and arabinoxylan degrading families. CONCLUSIONSCD impacted gut function and microbiota. GFD ameliorated but did not reverse these effects, significantly reducing Bifidobacteria associated with reduced intake of resistant starch and arabinoxylan from wheat.

physiology↗

bioRxiv2019

Primary infection with dengue or Zika virus does not affect the severity of heterologous secondary infection in macaques.

Zika virus (ZIKV) and dengue virus (DENV) are genetically and antigenically related flaviviruses that now co-circulate in much of the tropical and subtropical world. The rapid emergence of ZIKV in the Americas in 2015 and 2016, and its recent associations with Guillain-Barre syndrome, birth defects, and fetal loss have led to the hypothesis that DENV infection induces cross-reactive antibodies that influence the severity of secondary ZIKV infections. It has also been proposed that pre-existing ZIKV immunity could affect DENV pathogenesis. We examined outcomes of secondary ZIKV infections in three rhesus and fifteen cynomolgus macaques, as well as secondary DENV-2 infections in three additional rhesus macaques up to a year post-primary ZIKV infection. Although cross-binding antibodies were detected prior to secondary infection for all animals and cross-neutralizing antibodies were detected for some animals, previous DENV or ZIKV infection had no apparent effect on the clinical course of heterotypic secondary infections in these animals. All animals had asymptomatic infections and, when compared to controls, did not have significantly perturbed hematological parameters. Rhesus macaques infected with DENV-2 approximately one year after primary ZIKV infection had higher vRNA loads in plasma when compared with serum vRNA loads from ZIKV-naive animals infected with DENV-2, but a differential effect of sample type could not be ruled out. In cynomolgus macaques, the serotype of primary DENV infection did not affect the outcome of secondary ZIKV infection.\n\nAuthor summaryPre-existing immunity to one of the four DENV serotypes is known to increase the risk of severe disease upon secondary infection with a different serotype. Due to the antigenic similarities between ZIKV and DENV, it has been proposed that these viruses could interact in a similar fashion. Data from in vitro experiments and murine models suggests that pre-existing immunity to one virus could either enhance or protect against infection with the other. These somewhat contradictory findings highlight the need for immune competent animal models for understanding the role of cross-reactive antibodies in flavivirus pathogenesis. We examined secondary ZIKV or DENV infections in rhesus and cynomolgus macaques that had previously been infected with the other virus. We assessed the outcomes of secondary ZIKV or DENV infections by quantifying vRNA loads, clinical and laboratory parameters, body temperature, and weight for each cohort of animals and compared them with control animals. These comparisons demonstrated that within a year of primary infection, secondary infections with either ZIKV or DENV were similar to primary infections and were not associated with enhancement or reduction in severity of disease based on the outcomes that we assessed.

pathology↗

bioRxiv2018

Zika viruses of both African and Asian lineages cause fetal harm in a vertical transmission model

Congenital Zika virus (ZIKV) infection was first linked to birth defects during the American outbreak 1-3. It has been proposed that mutations unique to the Asian/American-genotype explain, at least in part, the ability of Asian/American ZIKV to cause congenital Zika syndrome (CZS) 4,5. Recent studies identified mutations in ZIKV infecting humans that arose coincident with the outbreak in French Polynesia and were stably maintained during subsequent spread to the Americas 5. Here we show that African ZIKV can infect and harm fetuses and that the S139N mutation that has been associated with the American outbreak is not essential for fetal harm. Our findings, in a vertical transmission mouse model, suggest that ZIKV will remain a threat to pregnant women for the foreseeable future, including in Africa, southeast Asia, and the Americas. Additional research is needed to better understand the risks associated with ZIKV infection during pregnancy, both in areas where the virus is newly endemic and where it has been circulating for decades.

microbiology↗