Effects of combined treatment with PD‑L1 Ig and CD40L mAb on immune tolerance in the CBA/J x DBA/2 mouse model

Regulatory T cell adoptive transfer alters uterine immune populations, increasing a novel MHC-IIlow macrophage associated with healthy pregnancy

Intrauterine fetal demise (IUFD) - fetal loss after 20 weeks - affects 6 pregnancies per 1,000 live births in the United States, and the majority are of unknown etiology. Maternal systemic regulatory T cell (Treg) deficits have been implicated in fetal loss, but whether mucosal immune cells at the maternal-fetal interface contribute to fetal loss is under-explored. We hypothesized that the immune cell composition and function of the uterine mucosa would contribute to the pathogenesis of IUFD. To investigate local immune mechanisms of IUFD, we used the CBA mouse strain, which naturally has mid-late gestation fetal loss. We performed a Treg adoptive transfer and interrogated both pregnancy outcomes and the impact of systemic maternal Tregs on mucosal immune populations at the maternal-fetal interface. Treg transfer prevented fetal loss and increased an MHC-IIlow population of uterine macrophages. Single-cell RNA-sequencing was utilized to precisely evaluate the impact of systemic Tregs on uterine myeloid populations. A population of C1q+, Trem2+, MHC-IIlow uterine macrophages were increased in Treg-recipient mice. The transcriptional signature of this novel uterine macrophage subtype is enriched in multiple studies of human healthy decidual macrophages, suggesting a conserved role for these macrophages in preventing fetal loss.

Ferroptosis: a double-edged sword mediating immune tolerance of cancer

The term ferroptosis was put forward in 2012 and has been researched exponentially over the past few years. Ferroptosis is an unconventional pattern of iron-dependent programmed cell death, which belongs to a type of necrosis and is distinguished from apoptosis and autophagy. Actuated by iron-dependent phospholipid peroxidation, ferroptosis is modulated by various cellular metabolic and signaling pathways, including amino acid, lipid, iron, and mitochondrial metabolism. Notably, ferroptosis is associated with numerous diseases and plays a double-edged sword role. Particularly, metastasis-prone or highly-mutated tumor cells are sensitive to ferroptosis. Hence, inducing or prohibiting ferroptosis in tumor cells has vastly promising potential in treating drug-resistant cancers. Immunotolerant cancer cells are not sensitive to the traditional cell death pathway such as apoptosis and necroptosis, while ferroptosis plays a crucial role in mediating tumor and immune cells to antagonize immune tolerance, which has broad prospects in the clinical setting. Herein, we summarized the mechanisms and delineated the regulatory network of ferroptosis, emphasized its dual role in mediating immune tolerance, proposed its significant clinical benefits in the tumor immune microenvironment, and ultimately presented some provocative doubts. This review aims to provide practical guidelines and research directions for the clinical practice of ferroptosis in treating immune-resistant tumors.

Sinomenine Improves Embryo Survival by Regulating Th1/Th2 Balance in a Mouse Model of Recurrent Spontaneous Abortion

Background

This study aims to explore the effect of Sinomenine (SIN) on pregnancy outcomes of recurrent spontaneous abortion (RSA) in a mouse model.

Material/Methods

Thirty female CBA/J mice were allocated into 3 groups randomly, then mated with BALB/c mice (CBA/J×BALB/c) as normal-pregnancy group (n=10), or mated with DBA/2 mice (CBA/J×DBA/2) as RSA model (n=10), or CBA/J×DBA/2 mice treated with SIN as RSA+SIN group (n=10). The number of surviving and reabsorbed embryos in each group were counted on day 13.5 of gestation. The mouse serum was collected to determine the levels of interferon-γ (IFN)-γ and IL-4 by ELISA. Immunohistochemistry, qRT-PCR and immunoblotting were used to determine the location, mRNA and protein expressions of IFN-γ, IL-4, T-bet and GATA3 in the decidual and placental tissue.

Results

In the RSA group, the amount of reabsorbed embryo was significantly higher than that in the normal-pregnancy group. However, SIN treatment showed a rescue effect on spontaneous abortion in RSA mice. IFN-γ, IL-4, T-bet, and GATA3 were all expressed in placental tissues and mainly located in the cytoplasm. The RSA group demonstrated higher expression levels of IFN-γ and T-bet than in the RSA+SIN and normal-pregnancy groups. Although RSA and RSA+SIN groups showed lower expression levels of IL-4 and GATA3 than in the normal-pregnancy group, there was no significant difference between RSA and RSA+SIN groups regarding IL-4 and GATA expression levels.

Conclusions

SIN treatment demonstrates a therapeutic effect on spontaneous abortion in RSA mice, possibly through regulating the balance of Th1/Th2 in maternal circulation and decidual tissues.

Diet Supplementation with Pomegranate Peel Improves Embryonic Survival in a Mouse Model of Early Pregnancy Loss

The peel of pomegranate fruit is a rich source of polyphenolic compounds with powerful antioxidant properties. We evaluated the therapeutic potential of pomegranate peel (PP) in the prevention of early pregnancy loss in a mouse model of embryonic mortality and abortion (female CBA/J x male DBA/2). CBA/J mice were divided into 3 groups: mice in control group (CONT group) were fed a standard diet, whereas mice in groups 2 and 3 were fed a standard diet supplemented with 1% PP (PP1% group) and 5% PP (PP5% group), respectively. All the mice were fed their diets for 10 days before mating and continued with the same diets for a further 14 days after mating. At day 14 of pregnancy the female mice were sacrificed and the placentas and maternal livers were harvested for measurement of the content of thiols and thiobarbituric acid reactive substances (TBARS), as biomarkers of oxidative stress, and the enzymatic activities of total superoxide dismutase (TSOD), copper/zinc SOD (SOD1), manganese SOD (SOD2), selenium glutathione peroxidase (GPX) and glutathione reductase (GR). Diet supplemented with 5% PP improved embryonic survival and reduced embryonic mortality from 28.2% (CONT) to 8.5% (PP5%). This was accompanied by increased activities of placental TSOD, SOD1 and SOD2, and thiol content. Diet supplemented with 5% PP also reduced placental oxidative stress as demonstrated by a decrease of placental TBARS content. This study highlights the potential of interventions with PP-supplemented diet before and during early pregnancy, in order to ameliorate embryonic survival and prevent early pregnancy loss.