Biology subjects

Germond, A.

Publications and source records attributed to Germond, A..

3 recordsLinked to original sources

bioRxiv2025

Maternal Influenza A Virus Infection Induces Antiviral and Immune Dysregulation in the Placenta and Fetus Without Vertical Transmission

Influenza A virus (IAV) infection during pregnancy is associated with stillbirth and preterm birth, but the degree to which IAV alters placental and fetal immunity is poorly understood. The objective of our study was to determine the immunologic impact of maternal IAV infection on the placenta and fetus in a pigtail macaque (Macaca nemestrina) model. Pregnant pigtail macaques were inoculated with 107 plaque forming units (PFU) of IAV [A/California/07/2009 (H1N1)] and underwent necropsy 5 days post-infection (N=11). Results were compared to uninfected historical controls (N=16). IAV inoculation induced maternal pneumonia in all cases. Stillbirth occurred in 18% (2/11) of IAV-infected pregnancies, but not in controls. While vertical transmission was not observed, low-level IAV viral RNA was detected in two placentas. In the placenta, maternal IAV infection was associated with increased IL-1{beta}, IL-18, and IFN-{beta} levels, and an upregulated type I interferon (IFN) transcriptional response. IAV infection was also associated with significantly higher frequencies of intermediate and non-classical monocytes, plasmacytoid dendritic cells, CD4 T cells, and NKT cells in the fetus (lung, lymph node, blood). Although placental immune and transcriptional perturbations were rarely correlated with maternal IAV disease indicators (e.g., maternal lung viral load/IFN-/IFN-{beta}/IL-6), there were consistent and significant correlations between these metrics and perturbed immune cell populations in the fetus (CD4+ and CD8+ T cells, plasmacytoid dendritic cells, monocyte sub-populations). Maternal IAV infection disrupted both placental and fetal immune environments, but only fetal immune alterations correlated with maternal lung disease severity. One Sentence SummaryMaternal influenza A virus infection in pregnant pigtail macaques dysregulates placental and fetal immunity, with disease severity correlating strongly with fetal, but not placental, immune perturbations.

systems biology↗

bioRxiv2020

Following embryonic stem cells, their differentiated progeny, and cell-state changes during iPS reprogramming by Raman spectroscopy

To monitor cell state transition in pluripotent cells is invaluable for application and basic research. In this study, we demonstrate the pertinence of use non-invasive, label-free Raman spectroscopy to monitor and characterize the cell state transition of mouse stem cells undergoing reprogramming. Using an isogenic cell line of mouse stem cells, reprogramming from neuronal cells was performed, and we showcase a comparative analysis of single cell spectral data of the original stem cells, their neuronal progenitors, and reprogrammed cells. Neural network, regression models, and ratiometric analysis were used to discriminate the cell states and extract several important biomarkers specific to differentiation or reprogramming. Our results indicated that the Raman spectrum allowed to build a low dimensional space allowing to monitor and characterize the dynamics of cell state transition at a single cell level, scattered in heterogeneous populations. Ability of monitoring pluripotency by Raman spectroscopy, and distinguish differences between ES and reprogrammed cells is also discussed.

systems biology↗

bioRxiv2018

Pairwise Efficiency: A new mathematical approach to qPCR data analysis increases the precision of the classical calibration curve assay

The real-time quantitative polymerase chain reaction (qPCR) is routinely used for quantification of nucleic acids and is considered the gold standard in the field of relative nucleic acid measurements. The efficiency of the qPCR reaction is one of the most important parameters that needs to be determined, reported, and incorporated into data analysis in any qPCR experiment. The Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines recognize the calibration curve as the method of choice for estimation of qPCR efficiency. The precision of this method has been reported to be between SD=0.007 (3 replicates) and SD=0.022 (no replicates). In this manuscript we present a novel approach to analysing qPCR data obtained by running a dilution series. Unlike previously developed methods, our method relies on a new formula that describes pairwise relationships between data points on separate amplification curves and thus operates extensive statistics (hundreds of estimations). The comparison of our method with classical calibration curve by Monte Carlo simulation shows that our approach can almost double the precision of efficiency and gene expression ratio estimations on the same dataset.

biochemistry↗