S100 proteins: An emerging cynosure in pregnancy & adverse reproductive outcome

Spatial Analysis of Placentae During Congenital Cytomegalovirus Infection Reveals Distinct Cellular Profiles in Immune Cells and Trophoblasts

Cytomegalovirus (CMV) is the most common cause of birth defects by an infectious agent. Approximately 10% of infants with congenital CMV (cCMV) infection are symptomatic. Infected infants can exhibit long-term effects such as sensorineural hearing and vision loss and neurodevelopmental delay. To date, the mechanisms by which cCMV infection results in symptomatic disease are incompletely understood. The placenta has been implicated as a main thoroughfare for vertical transmission, as both placental immune cells and trophoblasts can be infected by CMV. The goal of this study was to spatially investigate changes in genes and proteins from immune cells and trophoblasts during cCMV infection. Utilizing the NanoString GeoMx Digital Spatial Profiler, we noted that both immune cells and trophoblasts in CMV + placentae exhibited increased expression and upregulation of immune activation receptors and pathways. Pro-apoptotic proteins were decreased in CMV + placentae, as were transcripts associated with cell death pathways. Spatially, immune cells infiltrating into CMV + placental villi had more CD4 + T cells expressing cell death markers than those T cells in the decidua (p = 0.002). In contrast, the decidua exhibited a CD8+ T cell abundance with far less upregulation of immune activation receptors than in the villi (p=0.03). These data can inform and direct future research into the immune mechanisms CMV uses to infect, evade, and vertically transmit the virus to the fetus.

Alarmins and their pivotal role in the pathogenesis of spontaneous abortion: insights for therapeutic intervention

Alarmins are a class of molecules released when affected cells damaged or undergo apoptosis. They contain various chemotactic and immunomodulatory proteins or peptides. These molecules regulate the immune response by interacting with pattern recognition receptors (PRRs) and play important roles in inflammatory response, tissue repair, infection defense, and cancer treatment. Spontaneous abortion (SA) is a common pregnancy-related disease, and its pathogenesis has been puzzling clinicians, so it needs to be further studied. In this paper, we first reviewed the research status of various alarmins and SA, focusing on the role of high mobility box 1 (HMGB1), interleukin33 (IL-33), interleukin1β (IL-1β) and S-100 protein (S100 protein) in immune response, inflammation, embryonic development and abortion. Subsequently, this paper summarized the effect of alarmins on pregnancy outcome by influencing angiogenesis-related factors. Finally, from the perspective of aseptic inflammation, the pro-inflammatory signaling pathways involved in various alarmins and their targeted drugs were reviewed. By focusing on specific molecules in alarmins and their receptors and signaling pathways, we can more accurately conduct drug research and development. The purpose of this review is to explore the role of alarmins in SA, and provide important references for early detection of abortion risk, revealing the disease mechanism, developing new therapies and improving the prognosis of patients.

Metabolomic evolution of the postpartum dairy cow uterus

High rates of early pregnancy loss are a critical issue in dairy herds, particularly in seasonal, grazing systems. Components of the uterine luminal fluid (ULF), on which the early embryo depends for sustenance and growth, partly determine early pregnancy losses. Here, changes in ULF from early to mid-postpartum in crossbred dairy cows were explored, linking them with divergent embryo development. For this, the uteri of 87 cows at Day 7 of pregnancy at first and third estrus postpartum were flushed to collect ULF. Eighteen metabolites (chiefly organic acids and sugars) significantly varied in abundance across postpartum, indicating a molecular signature of physiological recovery consistent of the upregulation of pyrimidine metabolism and glycerophospholipid metabolism, and downregulation of pentose phosphate and taurine metabolism pathways. Joint pathway analysis of metabolomics data and a previously generated proteomics data set on the same ULF samples suggests key links between postpartum recovery and subsequent successful embryo development. These include upregulation of VEGFA and downregulation of metabolism, NRF2, T-cell receptor, which appear to improve the ULF's capacity of sustaining normal embryo development, and a putative osmo-protectant role of beta-alanine. These relationships should be further investigated to develop tools to detect and reduce early pregnancy loss in dairy cows.

Multifunctional Role of S100 Protein Family in the Immune System: An Update

S100 is a broad subfamily of low-molecular weight calcium-binding proteins (9–14 kDa) with structural similarity and functional discrepancy. It is required for inflammation and cellular homeostasis, and can work extracellularly, intracellularly, or both. S100 members participate in a variety of activities in a healthy cell, including calcium storage and transport (calcium homeostasis). S100 isoforms that have previously been shown to play important roles in the immune system as alarmins (DAMPs), antimicrobial peptides, pro-inflammation stimulators, chemo-attractants, and metal scavengers during an innate immune response. Currently, during the pandemic, it was found that several members of the S100 family are implicated in the pathophysiology of COVID-19. Further, S100 family protein members were proposed to be used as a prognostic marker for COVID-19 infection identification using a nasal swab. In the present review, we compiled the vast majority of recent studies that focused on the multifunctionality of S100 proteins in the complex immune system and its associated activities. Furthermore, we shed light on the numerous molecular approaches and signaling cascades regulated by S100 proteins during immune response. In addition, we discussed the involvement of S100 protein members in abnormal defense systems during the pathogenesis of COVID-19.