Selectin, Platelet Plays a Critical Role in Granulocyte Access to the Pregnant Mouse Uterus Under Physiological and Pathological Conditions1

Profiling mouse cochlear cell maturation using 10× Genomics single-cell transcriptomics

Juvenile and mature mouse cochleae contain various low-abundant, vulnerable sensory epithelial cells embedded in the calcified temporal bone, making it challenging to profile the dynamic transcriptome changes of these cells during maturation at the single-cell level. Here we performed the 10x Genomics single-cell RNA sequencing (scRNA-seq) of mouse cochleae at postnatal days 14 (P14) and 28. We attained the transcriptomes of multiple cell types, including hair cells, supporting cells, spiral ganglia, stria fibrocytes, and immune cells. Our hair cell scRNA-seq datasets are consistent with published transcripts from bulk RNA-seq. We also mapped known deafness genes to corresponding cochlear cell types. Importantly, pseudotime trajectory analysis revealed that inner hair cell maturation peaks at P14 while outer hair cells continue development until P28. We further identified and confirmed a long non-coding RNA gene Miat to be expressed during maturation in cochlear hair cells and spiral ganglia neurons, and Pcp4 to be expressed during maturation in cochlear hair cells. Our transcriptomes of juvenile and mature mouse cochlear cells provide the sequel to those previously published at late embryonic and early postnatal ages and will be valuable resources to investigate cochlear maturation at the single-cell resolution.

Addressing microchimerism in pregnancy by ex vivo human placenta perfusion

The physical connection of mother and offspring during pregnancy allows the bi-directional exchange of a small number of cells through the placenta. These cells, which can persist long-term in the recipient individual are genetically foreign to it and therefore fulfill the principle of microchimerism. Over the last years, pioneer research on microchimeric cells revealed their role in immune adaptation during pregnancy and priming of tolerogenic responses in the progeny. However, the mechanisms involved in cell transfer across the placenta barrier remain poorly investigated. In this review, we summarize the evidence of fetomaternal microchimerism, propose a mechanism for cell trafficking through the placenta and discuss the different models and techniques available for its analysis. Likewise, we aim to generate interest in the use of ex vivo placenta perfusion to investigate microchimerism in physiological and pathological settings.

Switched phenotypes of macrophages during the different stages of Schistosoma japonicum infection influenced the subsequent trends of immune responses

BACKGROUND

Macrophages play crucial roles in immune responses during the course of schistosomal infections.

METHODS

We currently investigated influence of immunocompetent changes in macrophages via microarray-based analysis, mRNA expression analysis, detection of serum cytokines, and subsequent evaluation of the immune phenotypes following the differentiation of infection-induced lymphocytes in a unique T1/T2 double-transgenic mouse model.

RESULTS

The gradual upregulation of genes encoding YM1, YM2, and interleukin (IL)-4/IL-13 receptors in infected mice indicated the role of type 2 alternatively activated macrophages (M2, AAMφs) in immune responses after Schistosoma japonicum egg production. FACS analysis showed that surface markers MHC class II (IA/IE) and CD8α⁺ of the macrophages also exhibited a dramatic change at the various time points before and after egg-production. The transgenic mouse experiments further demonstrated that the shifting of macrophage phenotypes influenced the percentage of helper T (Th)-2 cells, which was observed to be higher than that of Th1 cells, which increased only at 3 and 5 weeks post-infection. The differentiation of effector B cells showed a similar but more significant trend toward type-2 immunity.

CONCLUSION

These results suggest that the infection of mice with S. japonicum resulted in a final Th2- and Be2-skewed immune response. This may be due to phenotypic changes in the macrophages. The influence of alternatively activated macrophages was also activated by S. japonicum egg production. This study elucidated the existence of variations in immune mechanisms at the schistosome infection stages.

The role of omentin in early pregnancy losses

This prospective case-control study aimed to investigate the role of omentin, an anti-inflammatory adipokine in early pregnancy losses. The study comprised 47 women with spontaneous miscarriage at a gestational age of 8-12 weeks and 36 healthy pregnant women, matched for age, body mass index and gestational age, gravdity and parity. A significant negative correlation was determined between plasma omentin concentrations and body weight (r= -0.242, p = .027) and gestational age (r= -0.249, p = .023). Although not statistically, the women with spontaneous miscarriage had higher plasma concentrations of omentin compared to those with healthy pregnancies (7.798 ± 3.453 ng/ml vs. 7.200 ± 3.442 ng/ml, p = .435). This finding might support the hypothesis that increased inflammation plays a role in the etiopathogenesis of early pregnancy losses. These results revealed the potential use of omentin to predict unhealthy pregnancies.Impact statementWhat is already known on the subject of the paper? The exact mechanism of early pregnancy loss with euploid foetal karyotype has not been elucidated yet. An alteration in the physiological inflammatory response of pregnancy might be one of the mechanisms responsible for miscarriage.What does this study add? To the best of our knowledge, this is the first study to investigate the role of omentin in early pregnancy loss. The results obtained from this current study could be used to clarify the relationship between inflammatory processes and miscarriage.What are the implications for clinical practice and/or further research? Identification of the role of omentin in the process of early pregnancy losses would be helpful in order to design further studies to determine the feasibility of using omentin as a serum marker to predict the risk of miscarriage in early pregnancies. Additionally, understanding of the etiopathogenesis of early pregnancy losses with euploid karyotype will give a lead to further researches which could focus on exploring new interventions to detect and treat altered inflammation in early pregnancies.

Polymorphisms in the selectin gene cluster are associated with fertility and survival time in a population of Holstein Friesian cows

Selectins are adhesion molecules, which mediate attachment between leucocytes and endothelium. They aid extravasation of leucocytes from blood into inflamed tissue during the mammary gland’s response to infection. Selectins are also involved in attachment of the conceptus to the endometrium and subsequent placental development. Poor fertility and udder health are major causes for culling dairy cows. The three identified bovine selectin genes SELP, SELL and SELE are located in a gene cluster. SELP is the most polymorphic of these genes. Several SNP in SELP and SELE are associated with human vascular disease, while SELP SNP rs6127 has been associated with recurrent pregnancy loss in women. This study describes the results of a gene association study for SNP in SELP (n = 5), SELL (n = 2) and SELE (n = 1) with fertility, milk production and longevity traits in a population of 337 Holstein Friesian dairy cows. Blood samples for PCR-RFLP were collected at 6 months of age and animals were monitored until either culling or 2,340 days from birth. Three SNP in SELP_Ex4-6 formed a haplotype block containing a Glu/Ala substitution at rs42312260. This region was associated with poor fertility and reduced survival times. SELP_Ex8 (rs378218397) coded for a Val475Met variant locus in the linking region between consensus repeats 4 and 5, which may influence glycosylation. The synonymous SNP rs110045112 in SELE_Ex14 deviated from Hardy Weinberg equilibrium. For both this SNP and rs378218397 there were too few AA homozygotes present in the population and AG heterozygotes had significantly worse fertility than GG homozygotes. Small changes in milk production associated with some SNP could not account for the reduced fertility and only SELP_Ex6 showed any association with somatic cell count. These results suggest that polymorphisms in SELP and SELE are associated with the likelihood of successful pregnancy, potentially through compromised implantation and placental development.

Activation of MDL-1 (CLEC5A) on immature myeloid cells triggers lethal shock in mice

Systemic inflammatory response syndrome (SIRS) is a potentially lethal condition, as it can progress to shock, multi-organ failure, and death. It can be triggered by infection, tissue damage, or hemorrhage. The role of tissue injury in the progression from SIRS to shock is incompletely understood. Here, we show that treatment of mice with concanavalin A (ConA) to induce liver injury triggered a G-CSF-dependent hepatic infiltration of CD11b+Gr-1+Ly6G+Ly6C+ immature myeloid cells that expressed the orphan receptor myeloid DAP12-associated lectin-1 (MDL-1; also known as CLEC5A). Activation of MDL-1 using dengue virus or an agonist MDL-1-specific antibody in the ConA-treated mice resulted in shock. The MDL-1+ cells were pathogenic, and in vivo depletion of MDL-1+ cells provided protection. Triggering MDL-1 on these cells induced production of NO and TNF-α, which were found to be elevated in the serum of treated mice and required for MDL-1-induced shock. Surprisingly, MDL-1-induced NO and TNF-α production required eNOS but not iNOS. Activation of DAP12, DAP10, Syk, PI3K, and Akt was critical for MDL-1-induced shock. In addition, Akt physically interacted with and activated eNOS. Therefore, triggering of MDL-1 on immature myeloid cells and production of NO and TNF-α may play a critical role in the pathogenesis of shock. Targeting the MDL-1/Syk/PI3K/Akt/eNOS pathway represents a potential new therapeutic strategy to prevent the progression of SIRS to shock.

Highway to health; or How prenatal factors determine disease risks in the later life of the offspring

Fetal development is largely dependent on the mother. However, pregnancy maintenance and consequently fetal development are highly vulnerable and sensitive to disruption, triggered by, for example, prenatal stress challenge. Such prenatal stress challenge modulates the maternal endocrine and immune responses during pregnancy e.g. by decreasing levels of progesterone. Prenatal stress also has negative repercussions for the child's health later in life. It has been reported that prenatal stress increases the risk of the child to develop chronic immune diseases such as allergies and asthma. We therefore propose that prenatal stress challenge - associated with a decrease in maternal progesterone - impairs fetal immune development (immune ontogeny). Such impaired immune ontogeny carries over into postnatal life, rendering the child more prone to developing chronic immune diseases. This purported association urgently requires a fresh evaluation in order to identify biomarkers and cascades of events. In the present review, we outline candidate biomarkers involved in fetal immune ontogeny, which may be targets of prenatal stress challenge and subsequently determine offspring disease risk. Identification of these stress-sensitive biomarkers may allow detection of pregnant women at risk to deliver chronic immune disease-prone offspring. The creation of therapeutic interventions designed to prevent negative consequences of prenatal stress would then be within reach.