Cell-specific expression and signal transduction of C-C motif chemokine ligand 2 and atypical chemokine receptors in the porcine endometrium during early pregnancy

Protective effects of melatonin on deoxynivalenol-induced oxidative stress and autophagy in IPEC-J2 cells

This study explored protective effects of melatonin (MEL) on deoxynivalenol (DON)-induced toxicity in porcine jejunum epithelial cells (IPEC-J2). Cells were preexposed to MEL and then exposed to DON to detect cell viability, apoptosis, and oxidative stress indicators. Compared to DON treatment, pretreatment with MEL significantly increased cell proliferation. (P < 0.01), intracellular catalase (CAT) and superoxide dismutase (SOD) levels (P < 0.05), decreased apoptosis and oxidative stress, and significantly attenuated the inflammatory response. RNA-seq analysis revealed that MEL protects IPEC-J2 from the adverse effects of DON by affecting the expression of tight junction and autophagy pathway-related genes. Similarly, further experiments revealed that MEL partly prevented DON-induced disruption of intestinal barrier function and decreased autophagy induced by DON via activation of the AKT/mTOR pathway. In conclusion, these results demonstrated the preventive properties of MEL against DON-induced cell damage by activating the antioxidant system and Inhibition of autophagy.

The effect of C–C motif chemokine ligand 2 supplementation on in vitro maturation of porcine cumulus-oocyte complexes and subsequent developmental competence after parthenogenetic activation

Porcine embryos are used for a variety of applications. However, the maturation rate in vitro remains low, and novel in vitro maturation (IVM) techniques that facilitate the collection of mature oocytes are necessary. C-C motif chemokine ligand 2 (CCL2) is a key periovulatory chemokine present in cumulus-oocyte complexes (COCs). We aimed to examine the effects of CCL2 supplementation during IVM on oocyte maturation and embryonic development. The CCL2 concentration was significantly higher in porcine follicular fluid (pFF) derived from follicles &gt;8 mm in size than in pFF derived from smaller follicles. There was a significant increase in CCL2 mRNA levels in all follicular cells after IVM compared with that before IVM. We analyzed the localization of CCL2 and its receptor, the CCL2 receptor, in follicular cells. During IVM, different concentrations of CCL2 were added to COCs cultured in a maturation medium. After IVM, the group treated with 100 ng/mL CCL2 showed significantly higher metaphase II rates than the control group. All CCL2-treatment groups showed a significant increase in intracellular glutathione levels and a significant decrease in reactive oxygen species levels, compared to the control. In CCs treated with 100 ng/mL CCL2, the mRNA levels of BAX, CASP3, and NPR2 were significantly decreased. Furthermore, the mRNA levels of SOD1, SOD2, and CD44 were significantly increased. In oocytes treated with 10 ng/mL CCL2, mRNA levels of BAX and CASP3 were significantly decreased, whereas, NRF2 and NPM2 were significantly increased. ERK1 exhibited significantly increased mRNA expression in both CCs and oocytes treated with 10 ng/mL CCL2. The protein expression ratio of phosphorylated ERK1/2 to total ERK1/2 was significantly increased in CCs treated with 10 ng/mL CCL2. After parthenogenetic activation, cleavage rates were significantly improved in the 100 ng/mL CCL2 treatment group, and blastocyst formation rates were significantly enhanced in the 10 ng/mL CCL2 treatment group. Overall, our results suggest that IVM medium along with CCL2 improves porcine oocyte maturation and the development of parthenogenetically-activated embryos.

Expression of long noncoding RNAs in the ovarian granulosa cells of women with diminished ovarian reserve using high-throughput sequencing

Background

Infertility is a global reproductive-health problem, and diminished ovarian reserve (DOR) is one of the common causes of female infertility. Long noncoding RNAs (lncRNAs) are crucial regulators of numerous physiological and pathological processes in humans. However, whether lncRNAs are involved in the development of DOR remains to be elucidated.

Methods

Ovarian granulosa cells (OGCs) extracted from infertile women with DOR and from women with normal ovarian reserve (NOR) were subjected to high-throughput sequencing. Comprehensive bioinformatics analysis was conducted to identify the differential expression of messenger RNAs (mRNAs) and lncRNAs. Sequencing results were validated by the selection of lncRNAs and mRNAs using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

Compared with the NOR group, a total of 244 lncRNAs were upregulated (53 known and 191 novel), and 222 lncRNAs were downregulated (36 known and 186 novel) in the DOR group. Similarly, 457 mRNAs had differential expression between the two groups. Of these, 169 were upregulated and 288 were downregulated. Bioinformatics analysis revealed that the differentially expressed genes of mRNA and lncRNAs were considerably enriched in “cell adhesion and apoptosis”, “steroid biosynthesis”, and “immune system”. A co-expression network comprising lncRNAs and their predicted target genes revealed the possible involvement of the “thyroid hormone signaling pathway” and “protein binding, digestion and absorption” in DOR pathogenesis. The expression of SLC16A10 was positively regulated by multiple lncRNAs. After RT-qPCR validation of seven differentially expressed lncRNAs and mRNAs, respectively, the expression of lncRNA NEAT1, GNG12, ZEB2-AS1, and mRNA FN1, HAS3, RGS4, SUOX were in accordance with RNA-sequencing.

Conclusions

We presented the first data showing that the expression profiles of lncRNA and mRNA in OGCs between NOR and DOR patients using RNA sequencing. The lncRNAs and mRNAs that we identified may serve as novel diagnostic biomarkers for patients with DOR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-01053-6.

Reproductive toxicity of folpet through deregulation of calcium homeostasis in porcine trophectoderm and luminal epithelial cells during early pregnancy

Folpet, a fungicide, is utilized even in cosmetics and pharmaceuticals. The LD50 of folpet in mammals, birds, and fish is relatively high. Recently, several negative effects of folpet on the respiratory system and cornea have been reported. However, there is no study on the negative effects of folpet on maternal-fetus interactions. In the present study, we used porcine trophectoderm (pTr) cells and porcine luminal epithelial (pLE) cells to investigate the toxic effects of folpet during implantation. Folpet treatment decreased cell proliferation and promoted apoptosis with cell cycle arrest. In addition, the ERK, JNK, and AKT signal pathways were activated by folpet treatment. Folpet treatment induced calcium overload in pTr and pLE cells mediating antimigratory and antiadhesive effects in both cell lines. Co-treatment with calcium chelates decreased the anti-implantation effect of folpet. Overall, our results demonstrated potential reproductive toxicity of folpet in pig.

Reactive oxygen and nitrogen species regulate porcine embryo development during pre-implantation period: A mini-review

Significant porcine embryonic loss occurs during conceptus morphological elongation and attachment from d 10 to 20 of pregnancy, which directly decreases the reproductive efficiency of sows. A successful establishment of pregnancy mainly depends on the endometrium receptivity, embryo quality, and utero-placental microenvironment, which requires complex cross-talk between the conceptus and uterus. The understanding of the molecular mechanism regulating the uterine-conceptus communication during porcine conceptus elongation and attachment has developed in the past decades. Reactive oxygen and nitrogen species, which are intracellular reactive metabolites that regulate cell fate decisions and alter their biological functions, have recently reportedly been involved in porcine conceptus elongation and attachment. This mini-review will mainly focus on the recent researches about the role of reactive oxygen and nitrogen species in regulating porcine embryo development during the pre-implantation period.

Thrombin impairs the angiogenic activity of extravillous trophoblast cells via monocyte chemotactic protein-1 (MCP-1): A possible link with preeclampsia

Cytokines' secretion from the decidua and trophoblast cells has been known to regulate trophoblast cell functions, such as Extravillous trophoblasts (EVTs) cell migration and invasion and remodeling of spiral arteries. Defective angiogenesis and spiral arteries transformation are mainly caused by proinflammatory cytokines and excessive thrombin generation during preeclampsia. Monocyte chemotactic protein-1 (MCP-1), a crucial cytokine, has a role in maintaining normal pregnancy. In this study, we explored whether thrombin regulates the secretion of MCP-1 in HTR-8/SVneo cells; if yes, what is its function? We used HTR-8/SVneo cells, developed from first trimester villous explants of early pregnancy, as the model of EVTs. MCP-1 gene silencing was performed using gene-specific siRNA. qPCR and ELISA were performed to estimate the expression and secretion of MCP-1. Here, we found that thrombin enhanced the secretion of MCP-1 in HTR-8/SVneo cells. Proteinase-activated receptor-1 (PAR-1) was found as the primary receptor, regulating MCP-1 secretion in these cells. Furthermore, MCP-1 secretion is modulated via protein kinase C (PKC) α, β, and Rho/Rho-kinase-dependent pathways. Thrombin negatively regulates HTR-8/SVneo cells' ability to mimic tube formation in an MCP-1 dependent manner. In conclusion, we propose that thrombin-controlled MCP-1 secretion may play an essential role in normal placental development and successful pregnancy maintenance. Improper thrombin production and MCP-1 secretion during pregnancy might cause inadequate vascular formation and transformation of spiral arteries, which may contribute to pregnancy disorders, such as preeclampsia.

Melatonin improves uterine-conceptus interaction via regulation of SIRT1 during early pregnancy

Melatonin has been shown to improve in vitro fertilization and offspring survival after bacterial infection, but its role in regulating maternal-fetal communication during early pregnancy has not been investigated. Results of this study demonstrated expression of abundant melatonin receptors in conceptus and endometrium during early pregnancy. In gilts, expression of melatonin receptor 1A (MTNR1A or MT1) and melatonin receptor 1B (MTNR1B or MT2) increased in trophectoderm (Tr) and uterine luminal epithelium (LE) with advancing days during early pregnancy in a different manner. Melatonin increased proliferation and migration of porcine trophectoderm (pTr) cell, the percent pTr cells in the G2 phase of the cell cycle, and the expression of implantation-related genes by pTr cells and endometrial luminal epithelium (pLE). Melatonin also attenuated the production of LPS-induced pro-inflammatory cytokines and tunicamycin-induced endoplasmic reticulum (ER) stress-sensing proteins. The expression of sirtuin 1 (SIRT1) as a potential target of melatonin increased between Days 9 and 14 of gestation. Co-treatment with SIRT1 inhibitor EX527 and melatonin restored cell-cell interactions through PI3K and MAPK signaling. Knockdown of SIRT1 decreased the expression of implantation-related genes, as well as migration of pTr and pLE cells. The expression of microRNAs regulated by SIRT1 was suppressed in response to melatonin. Furthermore, melatonin significantly increased lipopolysaccharide (LPS)-reduced fertilization and embryogenesis in zebrafish model. These results suggest that melatonin may improve the uterine-conceptus interactions via the regulation of SIRT1 during early pregnancy.

Modulatory effect of chemokines on porcine endometrial stromal and endothelial cells

The endometrium undergoes cyclical changes during the estrous cycle and pregnancy. These alterations are controlled by various factors, including cytokines. The present study aimed to screen the effect of several chemokines (CCL2, CCL4, CCL5, CCL8, CXCL2, CXCL8, CXCL9, CXCL10, and CXCL12) on endometrial stromal and endothelial cells. Real-time PCR analysis revealed mRNA expression of all examined chemokines and their receptors in primary stromal cells and undetectable levels of CXCL9, CXCL10, and CXCR3 in endothelial cells. Immunocytochemical staining showed variable distribution of chemokine receptors in stromal and endothelial cells. All examined chemokines enhanced stromal cell proliferation, and CCL2 and CXCL12 also increased the migratory potential of these cells. The evaluation of a possible indirect effect of chemokines on angiogenesis and lymphangiogenesis demonstrated that CXCL12 may potentially negatively affect lymphatic vessel creation. Downregulation of VEGFC mRNA and protein expression was noticed after CXCL12 stimulation. Among all examined chemokines, CCL4 and CCL8 positively affected the proliferation and migration of endothelial cells. The number of capillary-like structures was significantly reduced after CXCL8, CXCL10, and CXCL12 stimulation. In conclusion, among all examined chemokines, CCL2 is thought to act as the modulator of stromal cell functions, whereas CCL4 and CCL8 are suggested to be potent factors directly stimulating blood vessel creation.

Deletion of atypical chemokine receptor 3 (ACKR3) increases immune cells at the fetal-maternal interface

Establishment of immune cell populations and adaptations in immune cells are critical aspects during pregnancy that lead to protection of the semi-allogenic fetus. Appropriate immune cell activation and trophoblast migration are regulated in part by chemokines, the availability of which can be fine-tuned by decoy receptors. Atypical chemokine receptor 3 (ACKR3), previously named C-X-C chemokine receptor 7 (CXCR7), is a chemokine decoy receptor expressed in placenta, but little is known about how this receptor affects placental development. In this study, we investigated the phenotypic characteristics of placentas from Ackr3^-/- embryos to determine how Ackr3 contributes to early placentation. In placentas from Ackr3^-/- embryos, we observed an increase in decidual compaction and in the size of the uterine natural killer cell population. Ackr3 knockdown in trophoblast cells led to a decrease in trophoblast migration. These findings suggest that this decoy receptor may therefore be an important factor in normal placentation.

Butylated hydroxyanisole induces testicular dysfunction in mouse testis cells by dysregulating calcium homeostasis and stimulating endoplasmic reticulum stress

Butylated hydroxyanisole (BHA), a synthetic phenolic antioxidant (SPA), has been used as a food additive. However, BHA acts as an environmental hormone, i.e., endocrine disruptor. Here, we investigated BHA-induced male reproductive dysfunction in mouse Leydig and Sertoli cells. We found that BHA suppressed proliferation and induced cell cycle arrest in TM3 and TM4 cells. Furthermore, we investigated mitochondrial permeabilization, expression profiles of pro-apoptotic and anti-apoptotic proteins, calcium influx, and endoplasmic reticulum (ER) stress in testicular cells after BHA treatment. The results indicated that BHA-mediated calcium dysregulation and ER stress downregulated steroidogenesis- and spermatogenesis-related genes in mouse testis cell lines. Additionally, proliferation of both TM3 and TM4 cells in response to BHA treatment was regulated via the Mapk and Akt signaling pathways. Therefore, constant BHA exposure may lead to testicular toxicity via mitochondrial dysfunction, ER stress, and abnormal calcium levels in the testis.

Butylated hydroxytoluene induces dysregulation of calcium homeostasis and endoplasmic reticulum stress resulting in mouse Leydig cell death

Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant that has been used as an additive for fat- or oil-containing foods. The exposure index value increases with extended usage of the chemical. Further, estimated total amount of BHT could exceed standard regulation, considering dietary intake or another exposure. Although BHT may induce side effects in reproductive systems, adequate research had not yet been performed to confirm them. In this study, we investigated the effects of BHT on mouse Leydig cells (TM3), which are components of testis. Our results indicated that BHT suppressed cellular proliferation and induced cell cycle arrest in TM3 cells. Moreover, BHT hampered cytosolic and mitochondrial calcium homeostasis in TM3 cells. Furthermore, BHT treatment led to endoplasmic reticulum (ER) stress and DNA fragmentation, simultaneously stimulating intrinsic apoptosis signal transduction. To elucidate the mode of action of BHT on Leydig cells, we performed western blot analysis and confirmed the activation of the PI3K/AKT and MAPK pathways. Collectively, our results demonstrated that BHT has toxic effects on mouse Leydig cells via induction of calcium dysregulation and ER-mitochondria dysfunction.

Alpha-solanine inhibits cell proliferation via mitochondrial dysfunction and inhibin synthesis in mouse testis In vitro and In vivo

Sertoli and Leydig cells provide key supporting roles in spermatogenesis. Various toxins have been studied in the TM3 and TM4 mouse testis cell lines to identify their regulatory effects. Alpha-solanine (α-solanine), a toxic compound found in the potato, has cytotoxic effects on various cells, including cancer cells. However, the effect of α-solanine on testis function has not been identified. In this study, we verified for the first time the anti-proliferative effect of α-solanine in mouse testes. α-Solanine reduced cell viability in TM3 and TM4 cells and reduced the expression of the cell cycle checkpoint genes Ccnd1 and Ccne1. We also detected changes in the mitochondrial membrane potential (MMP) and in the cytosolic calcium and intracellular signal pathways in both cell lines. α-Solanine induced AKT, P70S6K, S6, ERK1/2, and JNK activation in mouse testis cells. In addition, the inhibition of AKT with a pharmacological inhibitor (LY294002) demonstrated more synergic anti-proliferative effects than in the TM3 and TM4 cell lines treated only with α-solanine. Inha and Inhba mRNA expression also decreased in both cell lines and α-solanine i.p. injected mouse testes. Collectively, the results from this study verify the toxic effects of α-solanine on testes and male reproductive function.

Cysteine-X-cysteine motif chemokine ligand 12 and its receptor CXCR4: expression, regulation, and possible function at the maternal-conceptus interface during early pregnancy in pigs

Cysteine-X-cysteine (CXC) motif chemokine ligand 12 (CXCL12) and its receptor, CXC chemokine receptor type 4 (CXCR4), are involved in regulating the proliferation, migration, and survival of trophoblast cells and the maternal immune response in humans and mice. The present study examined the expression, regulation, and function of CXCL12 and CXCR4 at the maternal-conceptus interface during pregnancy in pigs. The endometrium expressed CXCL12 and CXCR4 mRNAs with the greatest CXCL12 abundance on Day 15 of pregnancy. CXCL12 protein was localized mainly in endometrial epithelial cells, while CXCR4 protein was localized in subepithelial stromal cells, vascular endothelial cells, and immune cells in blood vessels in the endometrium during the estrous cycle and pregnancy. CXCL12 protein was detected in uterine flushing on Day 15 of pregnancy. The conceptus during early pregnancy and chorioallantoic tissues during mid-to-late pregnancy expressed CXCL12 and CXCR4. Interferon-γ increased the abundance of CXCL12, but not CXCR4 mRNA in endometrial explants. Recombinant CXCL12 (rCXCL12) protein dose-dependently increased migration of cultured porcine trophectoderm cells and peripheral blood mononuclear cells (PBMCs). Furthermore, rCXCL12 caused migration of T cells, but not natural killer cells, in PBMCs. This study revealed that interferon-γ-induced CXCL12 and its receptor, CXCR4, were expressed at the maternal-conceptus interface and increased the migration of trophectoderm cells and T cells at the time of implantation in pigs. These results suggest that CXCL12 may be critical for the establishment of pregnancy by regulating trophoblast migration and T cell recruitment into the endometrium during the implantation period in pigs.

Chemokines as the modulators of endometrial epithelial cells remodelling

Previous studies highlighted chemokines as potential factors regulating changes in the endometrium during early pregnancy. The current study aimed to screen the effects of a broad range of chemokines and indicate those that are involved in porcine luminal epithelial (LE) cell remodelling. Messenger RNA expression of chemokines (CCL2, CCL4, CCL5, CCL8, CXCL2, CXCL8, CXCL10 and CXCL12) and both the mRNA and protein expression of their receptors (CCR1, CCR2, CCR3, CCR5, CXCR2, CXCR3, CXCR4) were detected in LE cells. Exogenous CCL8 enhanced the proliferative and migration potential of LE cells and their motility in the environment with its stable concentration. The adhesive properties of LE cells were negatively affected by CCL8. However, CXCL12 positively affected the proliferation, motility and adhesion of LE cells as well as caused a decrease in MUC1 mRNA expression. To conclude, our studies determined that exogenous chemokines affected critical endometrial epithelial cell functions in the context of embryo implantation. We suggest that of all the examined factors, chemokine CCL8 participates in the establishment of a proper environment for embryo implantation, whereas CXCL12, apart from participation in endometrial receptivity, promotes embryo attachment.

Fenbendazole induces apoptosis of porcine uterine luminal epithelial and trophoblast cells during early pregnancy

Fenbendazole, is an effective benzimidazole anthelmintic that prevents parasite infection in both human and veterinary health care. Although the well-known and effect of benzimidazole was recently shown to have a broad spectrum of biological abilities, such as anticancer and anti-inflammation activities, the mechanism of benzimidazole's antiproliferative effect via cell signaling pathways and its role in preimplantation has not been studied. Therefore, the purpose of this study was to determine the effects of fenbendazole on porcine trophectoderm and luminal epithelial cells. First, we investigated cell viability in response to a low dose of fenbendazole, which highly inhibited cell proliferation. In addition, we investigated apoptotic molecules in the mitochondria, imbalanced intracellular calcium homeostasis, and the expression of some genes involved in apoptosis to explain the decrease in proliferation. Finally, we examined the intracellular mechanisms of fenbendazole by measuring the extracellular signal-regulated kinase, PI3K/AKT, and c-Jun N-terminal kinase signaling proteins by western blot analysis. Our findings suggest that fenbendazole functions as an effective anti-proliferative molecule that induces critical apoptosis in the porcine trophectoderm and uterine luminal epithelial cells by disrupting the mitochondria membrane potential during early pregnancy.

Deoxynivalenol induces apoptosis and disrupts cellular homeostasis through MAPK signaling pathways in bovine mammary epithelial cells

Deoxynivalenol (DON), a fungus-derived mycotoxin, also known as vomitoxin, is found in a wide range of cereal grains and grain-based food products. The biological toxicity of DON has been described in various species, but its toxicity and functional effects in mammary epithelial cells are unclear. In this study, we investigated the effect of DON on bovine mammary epithelial (MAC-T) cells using mechanistic approaches. We detected DON-induced cell cycle abrogation and calcium deficiency, leading to apoptotic cell death via MAPK signaling pathways. Moreover, we studied the transcriptional activation of blood and milk junctional regulators as well as inflammatory cytokines in response to DON. The results of this study contribute to a comprehensive understanding of DON-associated toxicity mechanisms in bovine mammary epithelial cells, which may facilitate the enhancement of milk stabilization in parallel with the establishment of safety profiles to protect against DON contamination in livestock farms and in the food industry.

Ivermectin induces apoptosis of porcine trophectoderm and uterine luminal epithelial cells through loss of mitochondrial membrane potential, mitochondrial calcium ion overload, and reactive oxygen species generation

Ivermectin is a pesticide that has been used for over 30 years in livestock. Although there are a number of studies on the therapeutic potential of ivermectin, little is known about the effects of the drug during the early stage of pregnancy. In this study, we investigated the detrimental effects of ivermectin on porcine trophectoderm (pTr) and uterine luminal epithelial (pLE) cells. Ivermectin not only inhibited the proliferation of both cells via the regulation of cell cycle-associated genes, but also induced apoptosis in pTr and pLE cells. We also verified its effect on mitochondrial dysfunction as shown by loss of mitochondrial membrane potential, mitochondrial Ca²⁺ overload, and reactive oxygen species (ROS) generation in pTr and pLE cells. As a mechanistic approach, we evaluated ivermectin-mediated cell signaling interactions including PI3K, AKT and MAPK pathways. Overall, our results suggest that constant exposure to and accumulation of ivermectin may cause abnormal fetal morphogenesis and placentation during the early stages of pregnancy. Our results may further provide a comprehensive understanding of the detrimental effects of ivermectin during pregnancy and will contribute to the establishment of a complete safety profile for ivermectin and its association with environmental pollution and public health in humans and livestock.

Mitigation of ER-stress and inflammation by chemokine (C-C motif) ligand 21 during early pregnancy

The immune system plays an important role in pregnancy. Chemokines recruit leukocytes at the maternal-fetal interface during early pregnancy. However, the role of the chemokine, C-C motif chemokine ligand 21 (CCL21), is less known. The aim of this study was to identify the expression of CCL21 and its receptor, CCR7, in the endometrium during estrous cycle and early pregnancy, and to investigate the functional effects of CCL21 on porcine trophectoderm (pTr) and porcine uterine luminal epithelial (pLE) cells. Our results indicated that CCL21 and CCR7 are increased in the glandular (GE) and luminal epithelium (LE) of the endometrium during early pregnancy, compared to estrous pigs. Recombinant CCL21 improved pTr and pLE cell proliferation through activation of the PI3K and MAPK pathways and suppression of tunicamycin-induced endoplasmic reticulum (ER) stress or LPS-induced inflammation. Collectively, these results provide novel insights into CCL21-mediated signaling mechanisms at the maternal-fetal interface during early pregnancy.

Variable chemokine expression in porcine trophoblasts and endometrium during the peri-implantation period

Successful embryo implantation and its further development depends on appropriate endometrial remodelling. Porcine early pregnancy is associated with intensive endometrial angiogenesis and establishment of an immunotolerant environment for the embryo. An increasing number of factors are believed to participate in endometrial remodelling. The aim of this study was to elucidate the involvement of selected chemokines at the porcine maternal-foetal interface during the peri-implantation period. Real-time PCR analysis revealed several upregulated chemokines during the time of implantation, and Western blot/ELISA analyses and immunohistochemical staining confirmed their presence at the protein level. The gene expression of several chemokines and receptors was also confirmed in early porcine trophoblasts. The results indicated that IFNG, a porcine trophoblast signal, positively influenced the expression of some chemokines in endometrial cells. In conclusion, we suggest that some of the examined chemokines may be involved in endometrial communication with the trophoblast (CCL2, CCL5, CCL11, CXCL12), whereas others are implicated in the recruitment of immune cells and establishment of an immunotolerant environment for the embryo (CXCL9, CXCL10).

Ochratoxin A mediates cytotoxicity through the MAPK signaling pathway and alters intracellular homeostasis in bovine mammary epithelial cells

Ochratoxin A (OTA), a secondary metabolite of the genera Penicillium and Aspergillus, contaminates many types of food and causes apoptosis as well as immunosuppression in many animal species. However, a mechanistic analysis of OTA-mediated cytotoxicity in bovine mammary epithelial cells has not yet been performed. Hence, we investigated the effects of OTA on bovine mammary epithelial (MAC-T) cells using several mechanistic analyses. We report that OTA may induce cell cycle arrest and apoptosis via MAPK and JNK signaling pathways in MAC-T cells. Moreover, homeostasis of cellular components, such as that of the mitochondrial membrane, was disrupted by OTA, leading to a decrease in mitochondrial and cytosolic Ca²⁺ in MAC-T cells. In addition, we evaluated the effects of OTA on inflammatory responses and major tight junction regulators, such as occludin and claudin 3. In summation, we suggest that OTA contamination may adversely affect bovine mammary epithelial cells, leading to improper lactation and decreased milk quality. This article aims to improve the understanding of physiological mechanisms involved in lactation, in addition to providing a guideline for the stabilization of industrial milk production by countering exogenous contaminants in livestock.

Activation of CCL20 and its receptor CCR6 promotes endometrium preparation for implantation and placenta development during the early pregnancy period in pigs

The success of implantation and placentation during early pregnancy depends on the intrauterine environment of diverse histotrophs, including nutrients, growth factors, cytokines, and chemokines. Here, we determined the functional role and signal transduction of CC-motif chemokine 20 (CCL20) in the porcine endometrium during pregnancy. The expression of CCL20 and its receptor CCR6 was abundant in the glandular epithelium (GE) and luminal epithelium (LE) of the porcine endometrium during early pregnancy. Administration of CCL20 to porcine endometrial LE cells increased cellular proliferation with strong PCNA expression by activation of PI3K and MAPK signaling. Blocking PI3K and MAPK decreased the CCL20-mediated elevated proliferation of pLE cells. Moreover, the proliferation of pLE cells was enhanced by inhibiting the LPS-induced cytokines and tunicamycin-induced endoplasmic reticulum (ER) stress response proteins. Overall, these results suggest that CCL20 may improve the endometrial receptivity through inducing proliferative signal transduction in the porcine endometrium during the early gestational period.

Atypical chemokine receptors 1, 2, 3 and 4: Expression and regulation in the endometrium during the estrous cycle and pregnancy and with somatic cell nucleus transfer-cloned embryos in pigs

Atypical chemokine receptor (ACKR) 1, ACKR2, ACKR3, and ACKR4, chemokine decoy receptors that lack G-protein-mediated signaling pathways, internalize and degrade chemokines to control their availability and function. Chemokines play important roles in the endometrium during the estrous cycle and pregnancy, but the expression and regulation of ACKRs have not been determined in pigs. Therefore, we examined the expression of ACKRs in the endometrium throughout the estrous cycle and pregnancy and in conceptus tissues in pigs. ACKR1, ACKR2, ACKR3, and ACKR4 mRNA was expressed in the endometrium, with higher levels of ACKR3 on day 12 of the estrous cycle than in pregnancy and higher levels of ACKR4 on day 15 of pregnancy than in the estrous cycle. ACKR1, ACKR2, and ACKR3, but not ACKR4, mRNA was detected in conceptus and chorioallantoic tissues during pregnancy. ACKR2 and ACKR3 mRNA and ACKR4 protein were mainly localized to luminal epithelial cells and weakly to glandular epithelial cells in the endometrium. Increasing doses of progesterone increased the expression of ACKR2 and ACKR4 and decreased the expression of ACKR3 in endometrial tissues. On day 12 of pregnancy, the expression of ACKR4 mRNA was lower in the endometria of gilts with somatic cell nucleus transfer-derived conceptuses than in the endometria of gilts carrying conceptuses derived from natural mating. These results indicate that the expression of ACKRs is dynamically regulated at the maternal-conceptus interface, suggesting that ACKR proteins might play critical roles in regulating endometrial chemokines to support the establishment and maintenance of pregnancy in pigs.

Gossypol Induces Disruption of Spermatogenesis and Steroidogenesis in Male Mice

Gossypol, commonly found in cotton seeds, is hazardous to male reproductive physiology. Although several studies have indicated the toxicity of gossypol in human and animal reproduction, the mechanism of gossypol action in testes has not yet been elucidated. In the present study, we investigated the effects of gossypol in normal mouse testis cells, TM3 and TM4 cells, and in gossypol-treated C57BL/6 mice. We confirmed the antiproliferative effects of gossypol using cell viability assays, with PCNA as a proliferation marker, and cell cycle analysis. We also verified mitochondrial dysfunction and Ca²⁺ dysregulation in the cytosol of TM3 and TM4 cells, using JC-1 and Fluo-4 dyes. To confirm the cellular signaling mechanisms in testis cell lines, we performed Western blot analysis to assess the changes in MAPK and PI3K/Akt signal transduction, using their pharmacological inhibitors. Moreover, we screened the mRNA expression of genes involved in spermatogenesis and steroidogenesis in TM3 and TM4 cells. We also confirmed the mRNA expression and localization of genes regulating testis function in gossypol-treated and untreated mice testes. Collectively, we suggest that gossypol induces negative effects on testis function by reducing cell viability, mitochondrial membrane potential, and testis development-related genes in vitro and in vivo as well as by modulating the MAPK and PI3K signaling pathways.

Trichlorfon inhibits proliferation and promotes apoptosis of porcine trophectoderm and uterine luminal epithelial cells

Trichlorfon is an organophosphate insecticide widely used in agriculture. Additionally, it is applied to pigs for control of endo- and ectoparasites. Previous studies have shown the effects of trichlorfon in pigs during late stages of gestation; however, little is known about its effects during early pregnancy, including implantation and placentation. We investigated whether trichlorfon affects proliferation and apoptosis of porcine trophectoderm (pTr) and uterine luminal epithelial (pLE) cells. Trichlorfon inhibited the proliferation of pTr and pLE cells, as evidenced by cell cycle arrest, and altered the expression of proliferation-related proteins. In addition, trichlorfon induced cell death and apoptotic features, such as loss of mitochondrial membrane potential and DNA fragmentation, in pTr and pLE cells. Moreover, trichlorfon treatment decreased concentrations of Ca²⁺ in the cytoplasm in both cell lines and increased concentrations of Ca²⁺ in mitochondria of pTr cells. Trichlorfon inhibited the activation of phosphoinositide 3-kinase/AKT and mitogen-activated protein kinase signaling pathways in pTr and pLE cells. Therefore, we suggest that trichlorfon-treated pTr and pLE cells exhibited abnormal cell physiology which might lead to early pregnancy failure.

Chrysin disrupts intracellular homeostasis through mitochondria-mediated cell death in human choriocarcinoma cells

The trophoblast cells which form the placenta, have a high potential for invading other tissues. Owing to certain mechanisms, trophoblast cells may lose their ability to control cell proliferation, and develop into pregnancy-related tumors, known as choriocarcinomas. Choriocarcinomas mostly develop from the hydatidiform mole, which is frequently found in pregnant women. Owing to their ability to rapidly metastasize through the hematogenous route, choriocarcinomas are very hard to cure if not detected at the proper time. Although numerous studies are attempting to identify the major pathways in choriocarcinoma cells, the critical pathway responsible for the origin of choriocarcinomas is still unclear. In this study, we identified that chrysin has inhibitory effects on human choriocarcinoma cells. The study demonstrated that chrysin disrupts intracellular homeostasis by altering the mitochondrial membrane potential (MMP), cytosolic Ca²⁺ levels, production of reactive oxygen species (ROS), and lipid peroxidation, leading to the death of choriocarcinoma cells (JAR and JEG3). Additionally, the effects of chrysin on choriocarcinoma cells were found to be mediated via the regulation of the AKT, ERK1/2, and JNK signaling pathways. Altogether, the anti-cancer effects of chrysin can aid the development of a novel therapeutic strategy against the progression of human choriocarcinomas.

Characterization of C-C motif chemokine ligand 4 in the porcine endometrium during the presence of the maternal-fetal interface

Chemokines and their receptors play a crucial role in embryo implantation at the maternal-fetal interface during pregnancy. In this study, we investigated the role of CCL4 in development of the porcine endometrium in the early gestational period. Porcine CCL4 showed high similarity with the human counterpart, and mRNA expression of CCL4 and its receptor (CCR5) was predominantly present in the endometrium during early pregnancy. Treatment with CCL4 increased proliferation of porcine uterine luminal epithelial (pLE) cells by activation of PI3K and MAPK signal transduction. In addition, CCL4 recovered the endoplasmic-reticulum stress-reduced proliferation and decreased the unfolded protein response in pLE cells. Besides, the lipopolysaccharide-activated NF-κB pathway was suppressed in response to CCL4 in pLE cells. Inhibition of CCR5 decreased the proliferation of pLE cells and activation of the PI3K and MAPK pathways by CCL4. Furthermore, CCL4 enhanced conceptus-maternal interactions between porcine trophectoderm (pTr) cells and pLE cells during early pregnancy by activating expression of migration and implantation-related genes. Collectively, the results suggest that CCL4 may improve successful implantation in early pregnancy in pigs.