Expression of interferon-stimulated gene 15-kDa protein, cyclooxygenase (COX) 1, COX-2, aldo-keto reductase family 1, member B1, and prostaglandin E synthase in the spleen during early pregnancy in sheep

Modulation of PI3K/AKT/mTOR signaling pathway in the ovine liver and duodenum during early pregnancy

The liver and intestine play a critical role in nutrient absorption, storage, and metabolism. The aim of this study was to evaluate expression pattern of phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of the rapamycin (mTOR) signaling pathway that included PI3K, AKT1, mTOR, FoxO1, SREBP-1, PPARα, PTEN and FXR in the maternal liver and duodenum. Ovine livers and duodenums were sampled at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation, and RT-qPCR, western blot and immunohistochemistry analysis were used to detect mRNA and protein expression. The results showed that expression of PI3K, AKT1, p-mTOR, FoxO1, SREBP-1 and PTEN upregulated in the maternal liver, and PPARα upregulated in the duodenum. However, expression of FoxO1, SREBP-1 and PTEN in the duodenum downregulated during early pregnancy. In addition, expression levels of SREBP-1, PTEN and PPARα in the maternal liver, and PI3K in the duodenum peaked at day 13 of pregnancy. In addition, expression levels of PI3K, p-mTOR and FoxO1 in the liver, and AKT1 and p-mTOR in the duodenum peaked at day 16 of pregnancy. Nevertheless, expression levels of FXR both in the maternal liver duodenum downregulated at days 13 and 16 of pregnancy. In conclusion, early pregnancy regulated expression pattern of PI3K/AKT/mTOR signaling pathway in the ovine liver and duodenum in a pregnancy stage-specific and tissue-specific manner, which may be necessary for the adaptations in maternal hepatic nutrient metabolism and intestinal nutrient absorption early pregnancy.

Effects of early pregnancy on NOD-like receptor expression in the ovine endometrium

Introduction

Nucleotide-binding domain (NOD)-like receptors (NLRs) are expressed in the endometrium, and involved in modulating the female innate immune responses. There are conceptus-endometrial interactions during pregnancy, which ensure immune homeostasis of the maternal-fetal interface. The purpose of this study was to explore the effects of early pregnancy on NLR expression in the ovine endometrium.

Methods

Endometrial tissues were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group), and RT-qPCR, western blot and immunohistochemistry analysis were used to analyze the expression of NLRs, including NOD1, NOD2, major histocompatibility complex class II transactivator (CIITA), neuronal apoptosis inhibitor protein (NAIP), NLR family, pyrin domain-containing 1 (NLRP1), NLRP3 and NLRP7.

Results

Expression levels of NOD1, NOD2, NAIP, CIITA, NLRP1 and NLRP3 declined, but expression level of NLRP7 increased in the endometria during early pregnancy compared with nonpregnant ewes. In addition, NOD2 and CIITA proteins were located in the endometrium in a protein type-, cell type- and pregnancy status-specific manner.

Discussion

Early pregnancy modulated expression of NLR family in the ovine endometrium, which may be essential for conceptus-endometrial interactions and maternal-fetal interface immune homeostasis.

Changes in expression levels of Nod-like receptors in the spleen of ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) have critical effects on interfaces of the immune and reproductive systems, and the spleen plays a key role in both innate and adaptive immune functions. It is hypothesized that NLR family participates in maternal splenic immune regulation during early pregnancy in sheep. In this study, maternal spleens were collected on day 16 of the estrous cycle, and days 13, 16 and 25 of gestation (n = 6 for each group) in ewes. Expression of NLR family, including NOD1, NOD2, class II transactivator (CIITA), NLR family apoptosis inhibitory protein (NAIP), nucleotide-binding oligomerization domain, Leucine rich repeat and Pyrin domain containing 1 (NLRP1), NLRP3 and NLRP7, was analyzed using quantitative real-time PCR, Western blot and immunohistochemistry analysis. The results revealed that expression levels of NOD1, NOD2, CIITA and NLRP3 were downregulated at days 13 and 16 of pregnancy, but expression of NLRP3 was increased at day 25 of pregnancy. In addition, expression values of NAIP and NLRP7 mRNA and proteins were improved at days 16 and 25 of pregnancy, and NLRP1 was peaked at days 13 and 16 of pregnancy in the maternal spleen. Furthermore, NOD2 and NLRP7 proteins were limited to the capsule, trabeculae and splenic cords. In summary, early pregnancy changes expression of NLR family in the maternal spleen, which may be related with the maternal splenic immunomodulation during early pregnancy in sheep.

Expression of IkappaB Family in the Ovine Liver during Early Pregnancy

During normal pregnancy, there is a dynamic regulation of the maternal immune system, including the liver, to accommodate the presence of the allogeneic foetus in the uterus. However, it was unclear that the expression of the IkappaB (IκB) family was regulated in the ovine maternal liver during early pregnancy. In this study, sheep livers were collected at day 16 of the oestrous cycle (NP16), and days 13, 16 and 25 of gestation (DP13, DP16 and DP25), and RT-qPCR, Western blot and immunohistochemistry analysis were used to analyse the expression of the IκB family, including B cell leukemia-3 (BCL-3), IκBα, IκBβ, IκBε, IKKγ, IκBNS and IκBζ. The results revealed that expression of BCL-3, IκBβ, IκBε and IKKγ peaked at DP16, and the expression of IκBα was increased during early pregnancy. In addition, the expression of IκBζ peaked at DP13 and DP16, and IκBNS peaked at DP13. IκBβ and IKKγ proteins were located in the endothelial cells of the proper hepatic arteries and portal veins, and hepatocytes. In conclusion, early pregnancy changed the expression of the IκB family, suggesting that the modulation of the IκB family may be related to the regulation of maternal hepatic functions, which may be favourable for pregnancy establishment in sheep.

Early Pregnancy Regulates Expression of IkappaB Family in Ovine Spleen and Lymph Nodes

Early pregnancy modulates the maternal immune system, including the spleen and lymph nodes, which participate in maternal innate and adaptive immune responses. Methods: Ovine spleens and lymph nodes were sampled at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation, and qRT-PCR, Western blot and immunohistochemistry analysis were used to analyze the expression of the IκB family, including BCL-3, IκBα, IκBβ, IκBε, IKKγ, IκBNS and IκBζ. Early pregnancy induced expression of BCL-3, IκBα, IκBε, IKKγ and IκBζ, and expression of BCL-3, IκBβ and IκBNS peaked at day 16 of pregnancy in the spleen. However, early pregnancy suppressed the expression of BCL-3 and IκBNS, but stimulated the expression of IκBβ and IκBζ, and expression levels of IκBα, IκBβ, IκBε and IKKγ peaked in lymph nodes at days 13 and/or 16 of pregnancy. Early pregnancy changed the expression of the IκB family in the maternal spleen and lymph node in a tissue-specific manner, suggesting that the modulation of the IκB family may be involved in regulation of maternal functions of the spleen and lymph nodes, which are necessary for the establishment of maternal immune tolerance during early pregnancy in sheep.

Modulation of Nod-like Receptor Expression in the Thymus during Early Pregnancy in Ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) are involved in modulating the innate immune responses of the trophoblast and the placenta in normal pregnancy. The thymus participates in regulation of innate and adaptive immune responses. However, it is unclear whether expression of NLR is modulated in the maternal thymus during early pregnancy. In this study, thymuses were sampled at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation (n = 6 for each group) from ewes after slaughter. Different stages were chosen because the maternal thymus was under the different effects of interferon-tau and/or progesterone or not. RT-qPCR, Western blot and immunohistochemistry analysis were used to analyze the expression of the NLR family, including NOD1; NOD2; major histocompatibility complex class II transactivator (CIITA); NLR family apoptosis inhibitory protein (NAIP); nucleotide-binding oligomerization domain and Leucine-rich repeat and Pyrin domain containing protein 1 (NLRP1), NLRP3 and NLRP7. The results showed that expression level of NOD1 was changed with the pregnancy stages, and expression levels of NOD2, CIITA, NAIP, NLRP1, NLRP3 and NLRP7 mRNA and proteins were peaked at day 13 of pregnancy. The levels of NOD2 and CIITA were increased during early pregnancy. The stainings for NOD2 and NLRP7 proteins were located in epithelial reticular cells, capillaries and thymic corpuscles. In summary, pregnancy stages changed expression of NLR family in the maternal thymus, which may be related to the modulation of maternal thymic immune responses, and beneficial for normal pregnancy in sheep.

Early Pregnancy Modulates Expression of the Nod-like Receptor Family in Lymph Nodes of Ewes

NOD receptors (NLRs) mediate adaptive immune responses and immune tolerance. Nevertheless, it is not clear if gestation modulates the NLR signaling pathway in lymph nodes of ewes. In this study, lymph nodes of ewes were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation (n = 6 for each group). RT-qPCR, Western blot and immunohistochemistry analysis were used to analyze the expression of the NLR family, including NOD1, NOD2, CIITA, NAIP, NLRP1, NLRP3 and NLRP7. The data showed that early gestation enhanced expression of NOD1, CIITA, NLRP1, NLRP3 and NLRP7 mRNA, as well as proteins at day 16 of gestation, and the expression levels of NOD2, CIITA, NLRP1 and NLRP7 were higher at days 13 and 25 of gestation than day 16 of the estrous cycle. However, NOD1 expression was lower on days 13 and 25 of gestation compared to day 16 of the estrous cycle, and early gestation suppressed NAIP expression. In summary, early pregnancy modulated expression of the NLR family in ovine lymph nodes, which participates in immune regulation, and this modulation may be necessary for pregnancy establishment in ewes.

Changes in expression of nuclear factor kappa B subunits in the ovine thymus during early pregnancy

There is a pregnant maternal immunological tolerance that protects the fetus and promotes its growth, and nuclear factor kappa B (NF-κB) family participates in the regulation of innate immune and adaptive immune responses. The thymus is related to establishing central tolerance, and early pregnancy has effects on expression of a good number of genes and proteins in the maternal thymus in sheep. However, it is unclear whether early pregnancy changes expression of NF-κB subunits in the ovine thymus. In this study, the thymic samples were collected from day 16 of non-pregnant ewes, and days 13, 16 and 25 of pregnant ewes, and the expression of NF-κB members (NF-κB1, NF-κB2, RelA, RelB and c-Rel) was analyzed through real-time quantitative PCR, Western blot and immunohistochemical analysis. The results showed that c-Rel mRNA and protein upregulated at day 25 of pregnancy, and NF-κB1 mRNA and proteins increased at days 16 and 25 of pregnancy, and RelB mRNA and proteins enhanced during early pregnancy. However, expression levels of NF-κB2 and RelA were decreased during early pregnancy, but upregulated from day 13 to 25 of pregnancy. In addition, the RelA protein was located in the epithelial reticular cells, capillaries and thymic corpuscles. This paper reported for the first time that early pregnancy induced expression of NF-κB1, RelB and c-Rel, but inhibited expression of NF-κB2 and RelA in the maternal thymus during early pregnancy, which is involved in the central immune tolerance, and helpful for successful pregnancy in sheep.

Early pregnancy regulates the expression of prolactin and its receptor in the thymus, the liver, the spleen and lymph nodes in sheep

As a pituitary hormone, prolactin (PRL) is also synthesized by immune system cells, and exerts its effects on the immune system by binding to its receptor (PRLR) via endocrine and paracrine/autocrine pathways. The immune organs adapt to the presence of fetal alloantigens during pregnancy, and the immune system is composed of primary organs and secondary organs. The objective of this study is to analyze the effects of early pregnancy on expression of PRL and PRLR in maternal immune organs in sheep. In this study, the thymus, lymph node, the spleen and the liver were sampled at day 16 of the estrous cycle, and at days 13, 16, and 25 of pregnancy in ewes. Expression of PRL and PRLR was analyzed through quantitative real-time PCR, Western blot and immunohistochemistry. Our data showed that there were an upregulation of PRL and PRLR in the thymus, lymph node and the spleen, and a downregulation in the liver during early pregnancy in ewes. In conclusion, it is reported for the first time that early pregnancy has tissue specific effects on expression of PRL isoform and PRLR isoform in the thymus, lymph node, the spleen and the liver, which may be owing to these organs exerting different functions during early pregnancy, and necessary for the successful pregnancy in sheep.

Expression of nuclear factor kappa B in ovine maternal inguinal lymph nodes during early pregnancy

Background

Pregnancy-induced immunological changes contribute to the maternal immune tolerance. Nuclear factor kappa B (NF-κB) pathway participates in regulating both innate and adaptive immunities, and lymph nodes play key roles in adaptive immune reaction. However, it is unclear whether early pregnancy changes the expression of NF-κB family in maternal lymph node in sheep.

Methods

In this study, the samples of inguinal lymph nodes were collected from ewes on day 16 of the estrous cycle, and on days 13, 16 and 25 of pregnancy, and expression of NF-κB family, including NF-κB p105 (NFKB1), NF-κB p100 (NFKB2), p65 (RELA), RelB (RELB) and c-Rel (REL), were analyzed through real-time quantitative PCR, Western blot and immunohistochemical analysis.

Results

The expression levels of NF-κB p105 and c-Rel downregulated, but NF-κB p100 upregulated on day 25 of pregnancy. The expression levels of p65, RelB and c-Rel peaked at day 13 of pregnancy, and expression level of RelB was higher during early pregnancy comparing to day 16 of the estrous cycle. In addition, p65 protein was located in the subcapsular sinus and lymph sinuses.

Conclusion

This paper reported for the first time that early pregnancy has effects on the expression of NF-κB family, which may contribute to the maternal immunoregulation through blood circulation and lymph circulation during early pregnancy in sheep.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03373-7.

Intrauterine infusion of low levels of interferon-tau on day-8 post-estrus stimulates the bovine endometrium to secrete apolipoprotein-A1: A possible implication for early embryo tolerance

We previously reported that interferon-tau (IFNT), derived from day-7 blastocyst, generates anti-inflammatory responses in bovine endometrial epithelial cells (BEECs) in vitro. However, the real in vivo impact of early embryo-derived IFNT on the uterine proteomic profile is mostly unknown. This study aimed to investigate proteomic changes of uterine flush (UF) when infused with a low physiological level of IFNT without embryo on day-8 post-estrus and its possible impact on the uterine immunological microenvironment. First, a fresh medium was infused into the uterine lumen on day-6, from which UF was obtained 24 h later, and this procedure was repeated on day-7 (control UF). On day-8, this procedure was done with a medium containing recombinant bovine IFNT (100 pg/ml) (IFNT-supplemented UF). Control and IFNT-supplemented UF were tested for immune responses in peripheral blood mononuclear cells (PBMCs). Real-time PCR results revealed that IFNT-supplemented UF downregulated pro-inflammatory cytokines (TNFA, IL1B) and upregulated anti-inflammatory cytokine (TGFB1) and PTGES in PBMCs. Through 2-D PAGE, followed by TOF/TOF mass spectrometer, apolipoprotein-A1 (Apo-A1) protein was identified in the IFNT-supplemented UF, which was confirmed by ELISA analysis. Proteomic analysis revealed again that the in vitro stimulation of BEECs by IFNT upregulated Apo-A1 expression. Further, stimulation of PBMCs with recombinant bovine Apo-A1 downregulated TNFA and NFKB and upregulated TGFB1 and PTGES in PBMCs. Altogether, our results suggest that minute amounts of IFNT alone, normally secreted from bovine blastocyst, stimulate Apo-A1 secretion from the endometrial epithelium in the absence of embryo that initiates an anti-inflammatory environment, which could pave the way for the acceptance of early embryo in the uterus. This article is protected by copyright. All rights reserved.

Expression of nuclear factor kappa B components in the ovine maternal liver in early pregnancy periods

There is a systemic immunological adaptation to maintaining tolerance towards the allogeneic fetus, and the liver participates in the adaptive immune tolerance during normal pregnancy. Nuclear factor kappa B (NF-κB) signalings contribute to immune regulation and liver homoeostasis. The objective of this study is to explore the effects of early pregnancy on expression of NF-κB components in the maternal liver in sheep. The maternal livers were sampled on Day 16 of the estrous cycle, and Days 13, 16, and 25 of gestation, and the expression of NF-κB components, including NF-κB1 (p50), NF-κB2 (p52), RelA (p65), RelB, and c-Rel, was detected by quantitative real-time polymerase chain reaction (PCR), Western blot analysis, and immunohistochemical analysis. Our data revealed that early pregnancy inhibited the expression of NF-κB1 and c-Rel, but the expression of NF-κB1 and c-Rel was increased during early pregnancy. However, early pregnancy enhanced the expression of NF-κB2, RelA, and RelB with the pregnancy progress. In conclusion, early pregnancy regulates the expression of NF-κB components in the maternal livers, which may contribute to maintaining maternal liver homeostasis and immune tolerance during early pregnancy in sheep.

Aldose Reductase B1 in Pig Sperm Is Related to Their Function and Fertilizing Ability

Aldose reductase B1 (AKR1B1) has been reported to participate in the modulation of male and female reproductive physiology in several mammalian species. In spite of this, whether or not AKR1B1 could be related to sperm quality, functionality and fertilizing ability is yet to be elucidated. The present study, therefore, aimed to investigate: i) the presence of AKR1B1 in epididymal and ejaculated sperm; ii) the relationship between the AKR1B1 present in sperm and the physiology of the male gamete; iii) the liaison between the relative content of AKR1B1 in sperm and their ability to withstand preservation for 72 h; and iv) the potential link between sperm AKR1B1 and in vitro fertility outcomes. Immunoblotting revealed that AKR1B1 is present in both epididymal and ejaculated sperm with a similar relative content. Moreover, the relative levels of AKR1B1 in sperm (36 kDa band) were found to be negatively related to several kinematic parameters and intracellular calcium levels, and positively to the percentage of sperm with distal cytoplasmic droplets after storage. Finally, AKR1B1 amounts in sperm (36 kDa band) were negatively associated to fertilization rate at two days post-fertilization and embryo development at six days post-fertilization. The results of the present work suggest that AKR1B1 in sperm is probably acquired during maturation rather than at ejaculation and could play a role in that process. Moreover, AKR1B1 seems to be related to the sperm resilience to preservation and to their fertilizing capacity, as lower levels of the 36 kDa band (putative inactive form of this protein) result in better reproductive outcomes.

Complement regulation in ovine lymph nodes during early pregnancy

A fetus changes immune responses in the uterus and the maternal immune system, and lymph nodes are associated with regulating maternal adaptive immunity. Complement activation is associated with abnormal pregnancy in mice and humans. The aim of the present study was to explore the expression levels of complement components in maternal lymph nodes during early pregnancy in sheep. Maternal inguinal lymph nodes were sampled on day 16 of the estrous cycle, and days 13, 16 and 25 of gestation in ewes. Reverse transcription-quantitative PCR, western blotting and immunohistochemical analyses were used to detect the expression levels of complement components C1q, C1r, C1s, C2, C3, C4a, C5b and C9 in the lymph nodes. The results revealed that the protein and mRNA levels of C1q, C1s and C5b were enhanced during early pregnancy, and that C1r and C4a were upregulated at day 25 of pregnancy. The mRNA and protein levels of C2 and C9 peaked at day 16 of pregnancy, but C3 was decreased at day 25 of pregnancy. C3 protein was located in the subcapsular sinuses and lymph sinuses of the maternal lymph node. In summary, the present study detected changes in the expression levels of complement components in maternal lymph nodes, which may be associated with maternal immune regulation during early pregnancy in sheep.

Changes in Expression of Complement Components in the Ovine Spleen during Early Pregnancy

During early gestation in humans, complement regulation is essential for normal fetal growth. It is supposed that a complement pathway participates in maternal splenic immune regulation at the early stage of gestation in ewes. The aim of this study was to analyze the effects of early pregnancy on the expression of complement components in the maternal spleen of ewes. In this study, ovine spleens were sampled on day 16 of nonpregnancy, and days 13, 16 and 25 of gestation. RT-qPCR, Western blot and immunohistochemical analysis were used to detect the changes in expression of complement components in the ovine maternal spleens. Our results reveal that C1q was upregulated during early gestation, C1r, C1s, C2, C3 and C5b increased at day 25 of gestation and C4a and C9 peaked at days 13 and 16 of gestation. In addition, C3 protein was located in the capsule, trabeculae and splenic cords. In conclusion, our results show for the first time that there was modification in the expression of complement components in the ovine spleen at the early stage of gestation, and complement pathways may participate in modulating splenic immune responses at the early stage of gestation.

Toll-like receptor signaling is changed in ovine lymph node during early pregnancy

Toll-like receptors (TLRs) participate in regulation of adaptive immune responses, and lymph nodes play key roles in the initiation of immune responses. There is a tolerance to the allogenic fetus during pregnancy, but it is unclear that expression of TLR signaling is in ovine lymph node during early pregnancy. In this study, lymph nodes were sampled from day 16 of nonpregnant ewes and days 13, 16, and 25 of pregnant ewes, and the expressions of TLR family (TLR2, TLR3, TLR4, TLR5 and TLR9), adaptor proteins, including myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6), and interleukin-1-receptor-associated kinase 1 (IRAK1), were analyzed through real-time quantitative polymerase chain reaction, Western blot, and immunohistochemistry analysis. The results showed that mRNA and protein levels of TLR2, TLR3, TLR4, TRAF6, and MyD88 were upregulated in the maternal lymph node, but TLR5, TLR9, and IRAK1 were downregulated during early pregnancy. In addition, MyD88 protein was located in the subcapsular sinus and lymph sinuses. Therefore, it is suggested that early pregnancy induces changes in TLR signaling in maternal lymph node, which may be involved in regulation of maternal immune responses in sheep.

Early pregnancy affects expression of Toll-like receptor signaling members in ovine spleen

Toll-like receptors (TLRs) are involved to the maternal immune tolerance. The spleen is essential for adaptive immune reactions. However, it is unclear that early pregnancy regulates TLR-mediated signalings in the maternal spleen. The purpose of this study was to investigate the effects of early pregnancy on expression of TLR signaling members in the ovine spleen. Ovine spleens were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group). Real-time quantitative PCR, western blot and immunohistochemistry analysis were used to detect TLR signaling members, including TLR2, TLR3, TLR4, TLR5, TLR7, TLR9, myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6) and interleukin-1-receptor-associated kinase 1 (IRAK1). The results showed that expression levels of TLR2, TLR4 and IRAK1 were downregulated, but expression levels of TLR3, TLR5, TLR7, TLR9, TRAF6 and MyD88 were increased during early pregnancy. In addition, MyD88 protein was located in the capsule, trabeculae and splenic cords of the maternal spleen. This paper reports for the first time that early pregnancy has effects on TLR signaling pathways in the ovine spleen, which is beneficial for understanding the maternal immune tolerance during early pregnancy.

Changes in mRNA and protein levels of gonadotropin releasing hormone and receptor in ovine thymus, lymph node, spleen, and liver during early pregnancy

There exists maternal immunological modification in maternal immune organs during early pregnancy in mammals. Gonadotropin releasing hormone (GnRH) is widely distributed in vertebrate tissues, including immune organs. However, it is unclear that early pregnancy induces expression of GnRH and GnRH receptor (GnRHR) in ovine immune organs. The objective of this study was to explore the expression of GnRH and GnRHR in main immune organs (thymus, lymph node, spleen, and liver) during early pregnancy in sheep. Ovine thymus, lymph node, spleen and liver were sampled at day 16 of estrous cycle, and days 13, 16, and 25 of pregnancy. The expression of GnRH and GnRHR was detected through real-time quantitative PCR, Western blot and immunohistochemistry analysis. The results indicated that early pregnancy induced upregulation of mRNA and protein levels of GnRH and GnRHR in the maternal lymph node, spleen and liver, and mRNA and protein of GnRH in the maternal thymus, but mRNA and protein of GnRHR decreased in the maternal thymus during early pregnancy. In summary, the mRNA and protein levels of GnRH and GnRHR were changed in maternal thymus, lymph node, spleen and liver in a tissue specific manner during early pregnancy in sheep.

Renal tubular injury induced by glyphosate combined with hard water: the role of cytosolic phospholipase A2

Background

The combined effects of glyphosate and hard water on chronic kidney disease of unknown etiology (CDKu) have attracted much interest, but the mechanisms remain unknown. Cytoplasmic phospholipase A₂ (cPLA₂) plays a key role in the acute and chronic inflammatory reactions. This study explored the effect of glyphosate combined with hard water on renal tubules and the possible targets and mechanisms involved.

Methods

In vivo experiments were conducted to investigate the synergistic effects and potential mechanisms of glyphosate and hard water on renal tubular injury in mice.

Results

Administration of glyphosate in mice resulted in elevated levels of β2-microglobulin (β₂-MG), albumin (ALB), and serum creatinine (SCr) compared to control mice. This increase was more pronounce when glyphosate was combined with hard water. In the glyphosate-treated mice, small areas of the kidney revealed fibroblast proliferation and vacuolar degeneration, particularly at the higher dose of 400 mg/kg glyphosate. However, the combination of glyphosate and hard water induced an even greater degree of pathological changes in the kidney. Immunofluorescence and western blot analyses showed that glyphosate and hard water had a coordinated effect on calcium ions (Ca²⁺)-activated phospholipase A₂ and the activation may play a key role in inflammation and renal tubular injury. Exposure to glyphosate alone or glyphosate plus hard water increased the levels of oxidative stress markers and inflammatory biomarkers, namely, thromboxane A₂ (TX-A₂), leukotriene B₄ (LTB₄), prostaglandin E₂ (PGE₂), nitric oxide synthase (NOS), and nitric oxide (NO). Parameters of oxidative stress, including the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were decreased. Further analysis showed that the levels of these biomarkers were significantly different between the mice treated with glyphosate plus hard water and the mice treated with glyphosate alone.

Conclusions

These findings suggested that hard water combined with glyphosate can induce renal tubular injury in mice, and this may involve mitogen-activated protein kinases (MAPK)/cytosolic phospholipase A₂ (cPLA₂)/arachidonic acid (AA) and its downstream factors.

Changes in expression of prostaglandin synthase in ovine liver during early pregnancy

Liver can function as part of the innate and adaptive immune systems. We hypothesize that prostaglandins participate in the regulation of hepatic immune function during early pregnancy in sheep. The objective of this study was to elucidate expression of prostaglandin synthase in ovine liver during early pregnancy. Ovine livers were sampled on day 16 of the estrous cycle, and days 13, 16, and 25 of pregnancy, and the expression of prostaglandin synthases, including prostaglandin-endoperoxide synthase 1 (PTGS1), PTGS2, prostaglandin E synthase (PTGES), and aldo-keto reductase family 1, member B1, a prostaglandin F synthase (PGFS), were detected by quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry analysis. There were increases in the expression of mRNA and the proteins of PTGS2, PTGES, and PGFS in the livers during early pregnancy, but PTGS1 was decreased in the pregnant ewes. The PGFS protein was limited to the hepatocytes and the endothelial cells of the proper hepatic arteries and hepatic portal veins. In summary, the upregulation of PTGS2, PTGES, and PGFS and downregulation of PTGS1 may be involved in the maternal hepatic immune adjustment during early pregnancy in sheep.

Changes in expression of interferon-stimulated genes and ubiquitin activating enzyme E1-like in ovine thymus during early pregnancy

As the main signal for the maternal recognition in ruminants, interferon-tau (IFNT) stimulates expression of interferon-stimulated genes (ISGs) in uterus and many extrauterine tissues. However, it is unclear that early pregnancy induces expression of signal transducer and activator of transcription 1 (STAT1), myxovirusresistance 1 (Mx1), interferon-gamma-inducible protein 10 (IP-10) and ubiquitin activating enzyme E1-like protein (UBE1L) in maternal thymus. In this study, ovine thymuses were sampled on day 16 of the estrous cycle and on days 13, 16 and 25 of gestation, and the expression of STAT1, Mx1, IP-10 and UBE1L was detected by real-time quantitative PCR, Western blot and immunohistochemistry. The results revealed that the expression of STAT1 and IP-10 reached peaks on day 16 of pregnancy, and expression of Mx1 was enhanced on day 25 of pregnancy, and STAT1 protein was located in the epithelial reticular cells, capillaries and thymic corpuscles. However, expression of UBE1L was declined during early pregnancy. In conclusion, early pregnancy influences expression of STAT1, Mx1, IP-10 and UBE1L in maternal thymus, which may participate in regulation of maternal immune tolerance during early pregnancy in sheep.

Effects of early pregnancy on expression of interferon‐stimulated gene 15, STAT1, OAS1, MX1, and IP‐10 in ovine liver

Interferon-tau (IFNT) regulates maternal recognition during early pregnancy in ruminants. The liver can serve as a hematopoietic organ, and it has immune functions. This study hypothesized whether mRNA and proteins of interferon-stimulated genes (ISGs) induced by early pregnancy are upregulated in maternal liver. Therefore, we determined the expression of interferon-stimulated gene 15-kDa protein (ISG15), 2',5'-oligoadenylate synthetase 1 (OAS1), myxovirus resistance protein 1 (MX1), interferon-gamma-inducible protein 10 (IP-10), and signal transducer and activator of transcription 1 (STAT1) in maternal livers during early pregnancy in sheep. Ovine livers were sampled on day 16 of the estrous cycle, and days 13, 16, and 25 of pregnancy, and expression of ISGs was detected by quantitative real-time PCR, Western blot, and immunohistochemistry analysis. Our results showed that there were increases in expression of the mRNA and proteins of ISG15, OAS1, IP-10, STAT1, and MX1 during early pregnancy. STAT1 protein was limited to the hepatocytes, and endothelial cells of proper hepatic arteries and hepatic portal veins. In conclusion, the upregulation of ISG15, OAS1, IP-10, STAT1, and MX1 proteins may be implicated in maternal hepatic immune adjustment and other functions during early pregnancy in sheep.

Relative abundance and localization of interferon-stimulated gene 15 mRNA transcript in intra- and extra-uterine tissues during the early stages of pregnancy in sheep

The aim of this study was to investigate relative abundance and localization of ISG15 mRNA transcript in intra-uterine (trophoblast, endometrium) and extra-uterine (hypothalamus, anterior pituitary, corpus luteum) tissues before and during the period of conceptus implantation. Multiparous ewes (n = 16) were randomly allotted into four groups: pregnant or estrous cyclic on days of 12 and 16 (n = 4 per group) following estrus. Relative abundances of ISG15 mRNA transcript were determined in the endometrium, corpus luteum, hypothalamus, and anterior-pituitary using real time quantitative PCR. Localization of ISG15 mRNA transcript was evaluated using in situ hybridization. The presence of ISG15 mRNA transcript was only visualized in intra-uterine tissues including the endometrium and trophoblast on day 12 of pregnancy. The ISG15 mRNA transcript was detected in all tissues evaluated on day 16 of pregnancy. The abundance of ISG15 mRNA transcript was greater in the endometrium on day 12 of pregnancy than at other days when evaluations occurred while in all other tissues except the hypothalamus there were large abundances of ISG15 mRNA on day 16 of pregnancy. It is concluded that the ISG15 mRNA transcript is only present in intra-uterine tissues before conceptus implantation. The ISG15 mRNA transcript, however, is present in extra-uterine tissues of ewes during implantation probably due to an increased amount of interferon-tau in blood circulation that is produced by the developing embryo. Results also indicate, for the first time, that pregnancy is associated with an intra-hypothalamus and anterior pituitary increased abundance of ISG15 mRNA transcript in ewes.

Expression of melatonin receptors and CD4 in the ovine thymus, lymph node, spleen and liver during early pregnancy

As a pineal gland hormone, melatonin acts through its receptors to modulate the immune system. The immune system is composed of primary and secondary organs, and immune organs are adapted to the presence of the fetal alloantigen during pregnancy. However, it is unclear whether melatonin affects maternal immune organs during early pregnancy in sheep. In this study, the ovine thymus, lymph node, spleen and liver were sampled at day 16 of the oestrous cycle, and at days 13, 16 and 25 of pregnancy. The expression of melatonin receptor 1A (MT1), melatonin receptor 1B (MT2) and cluster of differentiation 4 (CD4) was detected by quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry experiments. Our results showed that during early pregnancy there was an upregulation of MT1 mRNA and protein in the thymus, lymph node and liver, and there was a downregulation in the spleen. The expression of MT2 mRNA and protein was increased in the thymus but decreased in the spleen and liver, and there was no significant change in the lymph node during early pregnancy. CD4 protein was upregulated in the thymus, lymph node and liver, but there were no significant changes in the spleen during early pregnancy. In conclusion, early pregnancy induces tissue-specific expression of MT1, MT2 and CD4, which may be due to the different functions of the thymus, lymph node, spleen and liver. Further, melatonin is involved in immune regulation of the maternal thymus, lymph node, spleen and liver during early pregnancy in sheep.

Early Pregnancy Induces Expression of STAT1, OAS1 and CXCL10 in Ovine Spleen

Interferon-tau is a maternal recognition factor in ruminant species, and spleen plays an essential role in regulating innate and adaptive immune responses. However, it is not fully understood that early pregnancy induces expression of interferon stimulated genes (ISGs) in the spleen during early pregnancy in ewes. In this study, spleens were collected from ewes at day 16 of the estrous cycle, and on days 13, 16, and 25 of gestation (n = 6 for each group), and RT-qPCR, western blot and immunohistochemistry analysis were used to detect the expression of signal transducer and activator of transcription 1 (STAT1), 2',5'-oligoadenylate synthetase 1 (OAS1), myxovirusresistance protein 1 (Mx1) and C-X-C motif chemokine 10 (CXCL10). The results revealed that STAT1, OAS1 and CXCL10 mRNA and proteins were upregulated in the spleens during early pregnancy, and STAT1 protein was located in connective tissue cells in the capsule and trabeculae, and blood cells and lymphocytes in the red pulp. However, early pregnancy had no significant effects on expression of MX1 mRNA and protein. In conclusion, early pregnancy induces expression of STAT1, OAS1 and CXCL10 in maternal spleen, suggesting that maternal spleen is involved in immune regulation of pregnancy in sheep.

Effect of early pregnancy on the expression of prostaglandin synthases in the ovine thymus

Thymus is a primary lymphoid organ, must adapt to the presence of fetal alloantigens. Prostaglandins (PGs) have diverse effects to activate or inhibit the immune response, but effects of early pregnancy on the expression of PG synthases in ovine maternal thymus are unclear. In this study, ovine thymic samples were obtained at day 16 of the estrous cycle, and days 13, 16 and 25 of pregnancy. The expression of PG synthases, including cyclooxygenase 1 (COX-1), COX-2, PGE2 synthase (PTGES), and a prostaglandin F2α synthase (Aldo-keto reductase family 1, member B1, AKR1B1), was evaluated using quantitative real-time PCR, Western blot and immunohistochemistry analysis. In addition, the thymus/body ratio was also calculated. Our results showed that the expression of COX-2 mRNA and protein, AKR1B1 mRNA and dimer were up-regulated on day 25 of pregnancy (P < 0.05), and expression of COX-1, PTGES mRNA and protein, AKR1B1 monomer and thymus/body ratio were similar at different stages of pregnancy and the estrous cycle. The immunohistochemistry results showed that the COX-2 and AKR1B1 proteins were located in the stromal cells, capillaries and thymic corpuscles. This is the first study to report that expression of COX-2 and AKR1B1 dimer is up-regulated in the maternal thymus during early pregnancy, suggesting that early pregnancy exerts its effects on maternal thymus, which is involved in immunomodulation during early pregnancy in sheep.