Endoplasmic Reticulum Stress and Homeostasis in Reproductive Physiology and Pathology

Ferroptosis contributed to endoplasmic reticulum stress in preterm birth by targeting LHX1 and IRE-1

Preterm birth (PTB) significantly contributed to neonatal mortality, emphasizing the need for a detailed understanding of its pathogenesis. This study aimed to explore the involvement of ferroptosis, an iron-dependent cell death process, in PTB and investigated the possible crosstalk with endoplasmic reticulum stress (ERS). First, we explored the occurrence of ferroptosis in placenta samples from PTB parturients. Then we established a ferroptosis cell model was established by subjecting trophoblast cells to hypoxia/reoxygenation (H/R), and found the ERS was induced in H/R exposed cells and was attenuated by ferroptosis inhibition using Fer-1, suggesting that ferroptosis could induce ERS. Meanwhile, we also induced ERS in trophoblast cells via tunicamycin (TM) treatment. Ferroptosis inhibition with Fer-1 alleviated TM-induced ER stress. TM treatment reduced trophoblast cell viability and migration while promoted apoptosis and autophagy, effects that were reversed by ferroptosis inhibition. Thus, targeting ferroptosis might help mitigate ER stress-related pathophysiological changes in PTB. Mechanically, we found two ERS mediators LIM homeobox 1 (LHX1)/Inositol-requiring enzyme 1 (IRE-1) were also upregulated in H/R treated cells. Silencing LHX1 or IRE-1 was demonstrated to reverse the H/R-induced ferroptosis. Additionally, rescue assays further revealed that LHX1 promoted ferroptosis by regulating IRE-1. In conclusion, ferroptosis contributed to ERS and was critically involved in PTB, highlighting the LHX1/IRE-1 axis as a promising therapeutic target for mitigating ferroptosis-related complications. These findings offered a foundation for innovative interventions in preterm birth.

Endoplasmic reticulum stress-autophagy axis is involved in copper-induced ovarian ferroptosis

Copper (Cu) contamination has emerged a global public health problem due to the extensive use of Cu in industrial production and daily life. Reproductive damage resulting from Cu exposure has been particularly evident. Wilson's disease (WD) is a recessive genetic disease characterized by impaired Cu metabolism. Female WD patients have often been associated with reproductive impairment. Ferroptosis, a form of iron-dependent regulated cell death, has been identified as being caused by massive lipid peroxide-mediated membrane damage. However, it remains unclear whether ferroptosis is associated with Cu-induced ovarian damage. In this study, the role of ferroptosis in ovarian damage induced by Cu accumulation and its underlying mechanisms were examined through both in vivo and in vitro experiments. The findings indicated that excessive Cu deposition in the ovaries could lead to follicular atresia and ovulation dysfunction, and trigger ferroptosis in ovarian and granulosa cells (GCs). The mechanism may be related to endoplasmic reticulum (ER) stress mediated by the protein kinase RNA-like ER kinase (PERK) pathway, and hyperactivation of autophagy. In addition, Cu-induced autophagy in GCs was found to increase intracellular iron levels via the ferritinophagy pathway, thereby inducing ferroptosis. We also found that mitochondrial reactive oxygen species (MitoROS) may be an onstream facilitator of Cu-induced ferroptosis via activation of the ER stress-autophagy pathway. Our findings suggested that ferroptosis is associated with Cu-induced ovarian damage and is regulated by the MitoROS-ER stress-autophagy axes. These results might provide insights for developing treatment for WD and other diseases related to Cu exposure.

Bromodomain and extraterminal protein inhibitor JQ1 induces maturation arrest and disrupts the cytoplasmic organization in mouse oocytes under in vitro conditions

JQ1, a small cell-permeable molecule is known for its potent inhibitory action on bromodomain and extraterminal (BET) proteins. Although earlier studies have shown its inhibitory effect on male gametogenesis, limited information is available about its influence on oocyte development. Since BET genes are known to exhibit regulatory functions on oocyte development and maturation, the present study aimed to investigate the effect of JQ1 on oocyte developmental competence under in vitro conditions. Germinal vesicle (GV) stage oocytes were collected from adult Swiss albino mice and subjected to in vitro maturation (IVM) in the presence of various concentrations of JQ1 (25, 50, and 100 μM). The metaphase II (MII) stage oocytes were assessed for cytoplasmic organization and functional competence at 24 h after IVM. A significant decrease in nuclear maturation (at 50 and 100 μM), symmetric cytokinesis, altered distribution of mitochondria and cortical granules, poorly organized actin and meiotic spindle, misaligned chromosomes, and elevated endoplasmic reticulum (ER) stress and oxidative stress was observed in JQ1-exposed oocytes. Presence of N-acetyl cysteine (NAC), in IVM medium resulted in significant reduction in JQ1-induced oxidative stress and symmetric cytokinesis. Administration of JQ1 (50 mg/kg, intra peritoneal) to adult Swiss albino mice primed with pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) did not affect the ovulation. However, a high degree of oocyte degeneration, elevated intracellular reactive oxygen species (ROS), and GRP78 expression was observed in JQ1-administered mice. In conclusion, our study reveals that BET inhibitor JQ1 has detrimental effects on oocyte function and development.

The transcription factor XBP1 regulates mitochondrial remodel and autophagy in spontaneous abortion

PURPOSE

Spontaneous abortion (SA) remains a clinical challenge in early pregnancy. It has been reported that endoplasmic reticulum stress (ERS) is implicated in pregnancy-related complications. However, the precise mechanistic role of ERS in SA pathogenesis remains elusive. This study aims to explore the therapeutic potential of targeting ERS-related decidual dysfunction in SA.

METHODS

An ERS model was established in both decidualized stromal cells (DSCs) and pregnant mice through tunicamycin (Tu) administration. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were performed to determine the interaction between XBP1s and the transcription factor binding site (TFBS) of tumor necrosis factor receptor-associated factor 6 (TRAF6). Mitochondrial membrane potential (MMP) and mitochondrial function were assessed using JC-1 and TMRM staining following ERS induction in DSCs. The effects of XBP1s inhibitors on mitochondrial metabolism and autophagy were evaluated through RT-qPCR, Western blotting, RNA-Seq, TUNEL assays, ROS and MitoSOX detection, and histological analyses in Tu-treated DSCs and SA patients. STF-083010 (STF) or shXBP1 was utilized to assess the inhibitory effects of X-box binding protein 1 (XBP1s) on DSC function both in vitro and in vivo.

RESULTS

We observed significant upregulation of XBP1s in decidual tissues from SA patients and Tu-exposed DSCs. Tu exposure significantly increased the proportion of TUNEL-positive cells and upregulated pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-18) in DSCs. XBP1s inhibition via shXBP1 or pharmacological inhibitor STF attenuated Tu-induced apoptosis and inflammatory cytokine expression. Notably, STF or shXBP1 treatment enhanced MMP and upregulated LC3-II expression in Tu-treated DSCs, indicating autophagy activation.Intriguingly, chloroquine (CQ)-mediated autophagy suppression exacerbated apoptosis in STF/Tu-co-treated DSCs, suggesting that XBP1s inhibition confers cytoprotection through autophagy induction. Mechanistically, XBP1s directly bound to the TFBS of TRAF6, a ubiquitin E3 ligase. TRAF6 overexpression exacerbated mitochondrial dysfunction and apoptosis while suppressing autophagy via inhibition of mTORC2/Akt pathway in Tu-treated DSCs.

CONCLUSION

XBP1s inhibition restored mitochondrial homeostasis and promoted autophagy by modulating the TRAF6/mTORC2 axis under ERS conditions, providing novel mechanistic insights into SA pathogenesis and potential therapeutic targets.

Hepatitis B surface antigen: carcinogenesis mechanisms and clinical implications in hepatocellular carcinoma

Liver cancer is the third leading cause of death globally, with hepatitis B virus (HBV) infection being identified as the primary risk factor for its development. The occurrence of HBV-related hepatocellular carcinoma (HCC) is attributed to various mechanisms, such as chronic inflammation and liver cell regeneration induced by the cytotoxic immune response triggered by the virus, abnormal activation of oncogenes arising from HBV DNA insertion mutations, and epigenetic alterations mediated by viral oncoproteins. The envelope protein of the HBV virus, known as hepatitis B surface antigen (HBsAg), is a key indicator of increased risk for developing HCC in HBsAg-positive individuals. The HBsAg seroclearance status is found to be associated with recurrence in HCC patients undergoing hepatectomy. Additional evidence indicates that HBsAg is essential to the entire process of tumor development, from initiation to advancement, and acts as an oncoprotein involved in accelerating tumor progression. This review comprehensively analyzes the extensive effects and internal mechanisms of HBsAg during the various stages of the initiation and progression of HCC. Furthermore, it highlights the importance and potential applications of HBsAg in the realms of HCC early diagnosis and personalized therapeutic interventions. An in-depth understanding of the molecular mechanism of HBsAg in the occurrence and development of HCC is provided, which is expected to develop more precise and efficient strategies for the prevention and management of HCC in the future.

Triclosan Caused Oocyte Meiotic Arrest by Modulating Oxidative Stress, Organelle Dysfunctions, Autophagy, and Apoptosis in Pigs

Triclosan (TCS) is a highly effective broad-spectrum antibacterial agent; however, the specific roles of TCS in oocyte maturation remain poorly understood. This research investigated the influence of TCS on biologically active processes during the in vitro maturation of porcine oocytes. Our results demonstrated that TCS significantly decreased the maturation rate of porcine oocytes in a concentration-dependent manner and impaired cumulus expansion. These detrimental effects were mediated by the disruption of mitochondrial function and distribution, leading to oxidative stress characterized by an accumulation of reactive oxygen species (ROS), a decrease in the expression of the antioxidant enzymes SOD2 and GSH, reduced ATP production, and a loss of mitochondrial membrane potential (ΔΨm). We also observed interference with endoplasmic reticulum (ER) distribution, disturbances in Ca2+ homeostasis, and fluctuations in ER stress, as evidenced by reduced expression of ER stress-related proteins. Furthermore, TCS exposure induced autophagy, as indicated by the levels of SQSTM1 (P62) and LC3-II. Additionally, TCS increased apoptosis rates, corresponding with a downregulation of Bcl-2 expression. Collectively, our findings suggest that exposure to TCS can impair cytoplasmic function, thereby affecting oocyte quality.

Endoplasmic reticulum stress and unfolded protein response play roles in recurrent pregnancy loss: A bioinformatics study

This study aims to explore whether endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) processes could be potential targets for preventive, diagnostic, and therapeutic for recurrent pregnancy loss (RPL). RPL datasets GSE165004 and GSE26787 were sourced from the GEO database, and ERS- and UPR-related gene sets were obtained from the MsigDB database. After differentially expressed genes (DEGs) identification, key genes were screened from intersecting DEGs in RPL-ERS and RPL-UPR datasets. The z-score algorithm was conducted to obtain phenotype scores. Functional enrichment and machine learning analyses were performed to assess gene function and diagnostic value evaluation. Interaction networks were conducted to investigate upstream regulated relationships of the key genes. Immune infiltration and single-cell RNA sequencing (scRNA-seq) were assessed to explore ERS and UPR functions at the cellular level. Totally 25 key genes RPL-ERS DEGs and 16 key genes RPL-UPR DEGs were identified. Among them, six key genes (NFYB, EXOSC2, UBQLN2, RNF139, DERL1, and FBXO27) were validated to show consistent expression trends in both RPL datasets. Functional enrichment highlighted their involvement in the immunity of RPL. Machine learning indicated the significant diagnostic value of these validated genes for RPL, with an accuracy rate of > 80 %. scRNA-seq analysis revealed elevated ERS and UPR expressions in monocytes/macrophages in RPL samples. In conclusion, ERS and UPR processes are associated with RPL occurrences, and were mainly upregulated in monocytes/macrophages within RPL samples. ERS and UPR processes may serve as potential targets for the prevention, diagnosis, and treatment of RPL.

Physiopathology of polycystic ovary syndrome in endocrinology, metabolism and inflammation

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder characterized by elevated androgen levels, ovarian cysts, and impaired ovulation in females. This condition is closely linked with various reproductive health issues and has significant impacts on endocrine and metabolic pathways. Patients with PCOS commonly exhibit hyperandrogenaemia and insulin resistance, leading to complications such as acne, hirsutism, weight fluctuations, and metabolic disturbances, as well as an increased risk for type 2 diabetes, cardiovascular disease, and endometrial cancer. Although extensive research has identified several mechanistic aspects of PCOS, a thorough understanding of its pathophysiology remains incomplete. This review aims to provide a detailed analysis of the physiological and pathological aspects of PCOS, covering endocrine, metabolic, and inflammatory dimensions, to better elucidate its etiological framework.

1α,25(OH)2D3 improves 17β-estradiol secretion and potentially alleviates endoplasmic reticulum stress in muskrat granulosa cells

Vitamin D3 plays an essential regulatory role in female reproduction. However, the studies on the correlation between vitamin D3 and muskrat reproduction are limited. This study aims to determine the role of the active form of vitamin D3, 1α,25-dihydroxytamin D3 [1α,25(OH)2D3], on muskrat ovarian granulosa cells (MGCs). The results showed that vitamin D receptor (VDR) was prominently localized in MGCs and 1α,25(OH)2D3 supplementation increased VDR signaling of MGCs. Meanwhile, 10 nM of 1α,25(OH)2D3 stimulated MGCs to secrete 17β-estradiol and enhanced the mRNA expression of steroidogenic enzymes. 1α,25(OH)2D3 also remarkably down-regulated MGCs endoplasmic reticulum stress according to the expression of GRP78, p-PERK, ATF4, and CHOP. In addition, RNA-seq analysis revealed that 10 nM of 1α,25(OH)2D3 activated the PI3K/Akt/mTOR and TNF pathways that contributed to the inhibition of MGCs apoptosis. Taken together, these findings suggest that 1α,25(OH)2D3-induced VDR signaling improves 17β-estradiol secretion and potentially alleviate MGCs endoplasmic reticulum stress through the PERK-ATF4-CHOP pathway.

Mycotoxin toxicity and its alleviation strategy on female mammalian reproduction and fertility

BACKGROUND

Mycotoxin, a secondary metabolite of fungus, found worldwide and concerning in crops and food, causes multiple acute and chronic toxicities. Its toxic profile includes hepatotoxicity, carcinogenicity, teratogenicity, estrogenicity, immunotoxicity, and neurotoxicity, leading to deleterious impact on human and animal health. Emerging evidence suggests that it adversely affects perinatal health and progeny by its ability to cross placental barriers.

AIM OF REVIEW

Due to its wide occurrence and potential toxicity on reproductive health, it is essential to understand the mechanisms of mycotoxin-related reproductive toxicity. This review summarizes the toxicities and mechanisms of mycotoxin on maternal and offspring reproduction among mammalian species. Approaches for effective mycotoxin alleviation are also discussed, providing strategies against mycotoxin contamination.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The profound mycotoxin toxicities in female mammalian reproduction affect follicle assembly, embryo development, and fetus growth, thereby decreasing offspring fertility. Factors from endocrine system such as hypothalamic-pituitary-gonadal axis and gut-ovarian axis, placenta ABC transporters, organelle and cytoskeleton dynamics, cell cycle control, genomic stability, and redox homeostasis are found to be closely related to mycotoxin toxicities. Approaches from physical, chemical, biological, and supplementation of natural antioxidants are discussed for the mycotoxin elimination, while their applications are not widespread. Available ways for mycotoxin and its toxicities alleviation need further study. Since a species-, time-, and dose-specific response might exist in mycotoxin toxicities, more consideration should be given to the protocols for mycotoxin toxicity studies, such as experimental animal models, exposure duration, and dosage. Specific mechanism for mycotoxin, especially form a molecular biology perspective, could be investigated with multi-omics technologies and advanced imaging techniques. Mass spectrometry with algorithms may provide more accurate exposure assessments, and it may be further helpful to identify the high-risk individuals in the future.

Endoplasmic reticulum stress of endometrial mesenchymal stem cells in endometriosis

OBJECTIVE

The human endometrium has significant regenerative abilities due to stem cells, which are vital in immunomodulation, immune tolerance, steroid hormone response, and inflammation. Endometriosis, an inflammatory gynecological disorder where endometrium-like tissue grows outside uterus, affects millions of women and often causes infertility. Recent research indicates that stem cells contribute to pathology of endometriosis. ER stress is implicated in various diseases, including endometriosis. This study aims to examine ER stress in eMSCs within endometriosis pathogenesis and uncover underlying disease mechanisms.

METHODS

Samples were collected from healthy subjects and women with endometriosis in both proliferative and secretory phases. eMSCs were isolated and characterized via flow cytometry. ER stress protein levels were assessed using proteomic analysis, with validation through Western Blot and immunofluorescence staining. Gene expression was analyzed by RT-qPCR, and ultrastructural examination of eMSCs was conducted using TEM. ER stress markers in tissue samples were detected in SUSD2+ eMSCs through immunofluorescence staining and visualized using a confocal microscope. Statistical analysis was performed using SPSS program.

RESULTS

The proteomics analysis uncovered ER stress-related proteins (DDRGK1, RTN3, ERp44, TMED2, TMEM33, TMX3) whose levels were significantly distinct from control group. Western Blot analysis and immunofluorescence staining results at protein level; RT-qPCR results at gene level supported these findings. TEM analysis also showed ultrastructural presence of ER stress in endometriosis groups.

CONCLUSION

Presence of ER stress in eMSCs in pathogenesis of endometriosis has been demonstrated using various methods. Our research has potential to shed light on pathology of endometriosis and offer promising avenues for non-invasive diagnosis and potential treatment.

Estrogen receptors in mitochondrial metabolism: age-related changes and implications for pregnancy complications

Estrogen hormones are primarily associated with their role as female sex hormones responsible for primary and secondary sexual development. Estrogen receptors are known to undergo age-dependent decreases due to age-related changes in hormone production. In the mitochondria, estrogen functions by reducing the production of reactive oxygen species in the electron transport chain, inhibiting apoptosis, and regulating mitochondrial DNA content. Moreover, estrogen receptors may be the key components in maintaining mitochondrial membrane potential and structure. Although estrogen plays a crucial role in the development of pregnancy, our understanding of how estrogen receptors change with aging during pregnancy remains limited. During pregnancy, estrogen levels are significantly elevated, with a corresponding upregulation of estrogen receptors, which play various roles in pregnancy. However, the exact role of estrogen receptors in pregnancy complications remains to be further investigated. The paper reviews the role of estrogen receptors in the regulation of mitochondrial metabolism and in pregnancy complications, with a special focus on the effect of age-related changes on estrogen levels and estrogen receptors function. We also address how estrogen maintains mitochondrial function, including reducing the production of reactive oxygen species in the electron transport chain, inhibiting apoptosis, regulating mitochondrial DNA content, and maintaining mitochondrial membrane potential and structure. However, the effects of estrogen on mitochondria-endoplasmic reticulum contacts have not been well studied. Based on these emergent roles in mitochondria, the differential roles of estrogen receptors in pregnancy complications are of great relevance. The paper emphasizes the association between maternal health and estrogen receptors and indicates the need for future research to elucidate the interdependence of estrogen receptor-regulated maternal health with mitochondrial function and their relationship with the gut microbiome. Overall, we summarize the important role of estrogen receptors during pregnancy and highlight the need for further research to better understand the role of estrogen receptors in aging and pregnancy complications. This not only helps to reveal the mechanism underlying the role of estrogen in maternal health but also has potential clinical implications for the development of new therapies targeting age-related diseases and pregnancy complications.

Impaired inducibility of immune regulatory capacity of peripheral B cells of patients with recurrent pregnancy loss

The pathogenesis of recurrent pregnancy loss (RPL) is unclear. RPL may have an association with disruption of immune tolerance. The aim of this study is to characterize the inducibility of immune regulatory ability in peripheral naïve B cells of patients with RPL. In this study, blood samples were taken from patients with RPL. B220+ B cells were isolated by flow cytometry cell sorting. The gene profile of B cells was analyzed using RNA sequencing (RNAseq). The results showed that peripheral B220+ B cells of RPL patients had lower expression of IL10 and exacerbated ER stress. The induction of IL10 expression in peripheral B220+ B cells of RPL patients were impaired. High ubiquitination of c-Maf inducing protein (CMIP) was detected in RPL B cells. Exposure to thapsigargin (an ER stress agonist) decreased the amount of CMIP in B cells. The effects of ER stress on reducing CMIP quantity in B cells were mediated by the histone H2B E3 ubiquitin ligase ring finger protein 20 (RNF20). Inhibition of RNF20 or ER stress restored the inducibility of immune regulatory functions of B220+ B cells of RPL patients. In summary, peripheral B cells in patients with RPL show impaired immune regulation capacity, in which exacerbated ER stress plays a crucial role. Regulation of ER stress or inhibition of RNF20 can restore the immune regulatory capacity in the B cells.

Flupyradifurone activates DUM neuron nicotinic acetylcholine receptors and stimulates an increase in intracellular calcium through the ryanodine receptors

Insect neuronal nicotinic acetylcholine receptors (nAChRs) are transmembrane receptors that play a key role in the development and synaptic plasticity of both vertebrates and invertebrates, and are considered to be major targets of several insecticides. We used dorsal unpaired median (DUM) neurons, which are insect neurosecretory cells, to explore what type of nAChRs are involved in flupyradifurone's (FLU) mode of action, and to study the role of calcium release from intracellular stores in this process. Using whole-cell patch-clamp and fura-2-AM calcium imaging techniques, we found that inhibition of IP3Rs through application of 2-APB reduced FLU inward currents, but did not affect the intracellular calcium release induced by FLU. In contrast, inhibition of RyRs using ryanodine, led to reduction of intracellular calcium increase following FLU pulse application. These results suggested that FLU inward currents are likely due to a combination of the direct effects of FLU on DUM neuron nAChRs and the subsequent calcium release from RyRs.

The endoplasmic reticulum protein HSPA5/BiP is essential for decidual transformation of human endometrial stromal cells

Decidualization denotes the process of inflammatory reprogramming of endometrial stromal cells (EnSC) into specialized decidual cells (DC). During this process, EnSC are subjected to endoplasmic reticulum (ER) stress as well as acute cellular senescence. Both processes contribute to the proinflammatory mid-luteal implantation window and their dysregulation has been implicated in reproductive failure. Here, we evaluated the link between ER stress, decidual differentiation and senescence. In-silico analysis identified HSPA5 gene, codifying the ER chaperone BiP, as a potentially critical regulator of cell fate divergence of decidualizing EnSC into anti-inflammatory DC and pro-inflammatory senescent decidual cells (snDC). Knockdown of HSPA5 in primary EnSC resulted both in decreased expression of DC marker genes and attenuated induction of senescence associated β-galactosidase activity, a marker of snDC. Stalling of the decidual reaction upon HSPA5 knockdown was apparent at 8 days of differentiation and was preceded by the upregulation of ER stress associated proteins IRE1α and PERK. Further, HSPA5 knockdown impaired colony-forming unit activity of primary EnSC, indicative of loss of cellular plasticity. Together, our results point to a key role for HSPA5/BiP in decidual transformation of EnSCs and highlight the importance of constraining ER stress levels during this process.

The mechanism of paclitaxel induced damage on placental trophoblast cells

OBJECTIVE

Chemotherapy during pregnancy has a certain risk of causing a series of complications, such as miscarriage, premature birth, or fetal growth restriction, although the relationship between these complications and chemotherapy is currently unclear. This experiment focuses on the possible damage mechanism of the chemotherapeutic drug paclitaxel on placental trophoblast cells, and explores whether chemotherapy can affect pregnancy outcomes by directly damaging placental tissue.

METHODS

This study explored the mechanism of paclitaxel induced damage on placental trophoblast cell lines JEG-3 and BEWO through immunofluorescence staining, Western blot experiments, cell flow cytometry, Seahorese cell metabolism experiments, and mouse modeling verification.

RESULTS

The experiment found that paclitaxel could induce JEG-3 and BEWO cells to produce reactive oxygen species (ROS), and elevate the ratio of Bax/Bcl-2 expression. Besides, paclitaxel mediated the reduction of mitochondrial membrane potential in JEG-3 and BEWO cells, causing damage and leading to mitochondrial autophagy and the occurrence of unfolded protein response. Paclitaxel inhibited the glycolysis rate of JEG-3 and BEWO cells, and leaded to impaired mitochondrial function, including decreased basal respiratory values, decreased respiratory reserve capacity, and proton leakage. In pregnant mice with tumor modeling, paclitaxel could cause DNA damage in placental tissue cells, and might lead to apoptosis of chemotherapy mice placental tissue cells and impairment of normal physiological functions.

CONCLUSION

Paclitaxel may directly or indirectly affect the normal physiological functions of placental trophoblast cells, including energy metabolism and protein synthesis dysfunction, which may be related to the adverse pregnancy outcomes caused by paclitaxel chemotherapy.

Impact of the near-physiological temperature on the in vitro maturation of bovine oocytes: A comparative proteomic approach

In vivo, the temperature inside preovulatory follicles of cows is approximately 1 °C lower than rectal temperature. However, standard bovine oocyte in vitro maturation (IVM) protocols use 38.5 °C based on rectal temperature. This study evaluated the effect of reducing IVM temperature to 37.5 °C on the proteomic profile of oocytes compared to the routine 38.5 °C. Nuclear maturation rate and cumulus cell (CC) expansion (30 COCs per group, 21 replicates) were assessed by observing the first polar body and using a subjective scoring method (0-4). Total nitrite concentrations in the culture medium were measured using the Griess method. Differential proteomics was performed using LC-MS/MS on pooled oocyte samples (500 matured oocytes per group, three replicates), followed by gene ontology enrichment, protein-protein interaction, and putative miRNA target analyses. No significant differences were observed between the groups in nuclear maturation, CC expansion, or nitrite concentration (P > 0.05). A total of 806 proteins were identified, with 7 up-regulated and 12 down-regulated in the treatment group compared to the control. Additionally, 12 proteins were unique to the control group, and 8 were unique to the treatment group. IVM at 37.5 °C resulted in the upregulation of proteins involved in protein folding and GTP binding, and the downregulation of enzymes with oxidoreductase activity and proteins involved in cytoskeletal fiber formation. Furthermore, 43 bovine miRNAs potentially regulating these genes (DES, HMOX2, KRT75, FARSA, IDH2, CARHSP1) were identified. We conclude that IVM of bovine oocytes at 37.5 °C induces significant proteomic changes without impacting nuclear maturation, cumulus cell expansion, or nitrite concentration in the IVM medium.

Melatonin decreases excessive polyspermy for single oocyte in pigs through the MT2 receptor

Melatonin supplementation during in vitro maturation (IVM) improves porcine oocyte maturation and embryonic development by exerting antioxidative effects. Nevertheless, the mechanism by which melatonin prevents polyspermy after in vitro fertilization (IVF) remains unclear. Here, we examined the effects of melatonin on cytoplasmic maturation and the incidence of polyspermic penetration in porcine oocytes. No statistically significant difference was observed in the rate of first polar body formation between the groups (Control, Melatonin, Melatonin + Luzindole, and Melatonin + 4-P-PDOT). Interestingly, melatonin supplementation significantly improved the cytoplasmic maturation of porcine oocytes by enhancing the normal distribution of organelles (Golgi apparatus, endoplasmic reticulum and mitochondria) and upregulating organelle-related gene expressions (P < 0.05). However, these promotional effects were counteracted by melatonin antagonists, suggesting that melatonin enhances cytoplasmic maturation through its receptors in porcine oocytes. Melatonin supplementation also significantly improved the rate of diploid and blastocyst formation after IVF by promoting the normal distribution of cortical granules (P < 0.05). In conclusion, melatonin supplementation during in vitro maturation of porcine oocyte improves fertilization efficiency and embryonic developmental competence by enhancing cytoplasmic maturation.

Investigation of endoplasmic reticulum stress-regulated chaperones as biomarkers in idiopathic nonobstructive azoospermia

Azoospermia is a condition in which sperm cells are completely absent in a male's ejaculate. Typically, sperm production occurs in the testes and is regulated by a complex series of cellular and molecular interactions. Endoplasmic reticulum (ER) stress arises when there is a deviation from or damage to the normal functions of the ER within cells. In response to this stress, a cascade of response mechanisms is activated to regulate ER stress within cells. This study aims to investigate the role of ER stress-regulated chaperones as potential biomarkers in male infertility. ER stress associated with azoospermia can manifest in cells such as spermatogonia in the testes and can impact sperm production. As a result of ER stress, the expression and activity of a variety of proteins within cells can be altered. Among these proteins are chaperone proteins that regulate the ER stress response. The sample size was calculated to be a minimum of 36 patients in each group. In this preliminary study, we measured and compared serum levels of protein disulfide-isomerase A1, protein disulfide-isomerase A3 (PDIA3), mesencephalic astrocyte-derived neurotrophic factor (MANF), glucose regulatory protein 78 (GRP78), clusterin (CLU), calreticulin (CRT), and calnexin (CNX) between male subjects with idiopathic nonobstructive azoospermia and a control group of noninfertile males. Serum PDIA1 (P = 0.0004), MANF (P = 0.018), PDIA3 (P < 0.0001), GRP78 (P = 0.0027), and CRT (P = 0.0009) levels were higher in the infertile group compared to the control. In summary, this study presents novel findings in a cohort of male infertile patients, emphasizing the significance of incorporating diverse biomarkers. It underscores the promising role of ER stress-regulated proteins as potential serum indicators for male infertility. By elucidating the impact of ER stress on spermatogenic cells, the research illuminates the maintenance or disruption of cellular health. A deeper understanding of these results could open the door to novel treatment approaches for reproductive conditions, including azoospermia.

Short and long-term 2100 MHz radiofrequency radiation causes endoplasmic reticulum stress in rat testis

Long-term radiofrequency radiation (RFR) exposure, which adversely affects organisms, deteriorates testicular functions. Misfolding or unfolding protein accumulation in the endoplasmic reticulum (ER) initiates an intracellular reaction known as ER stress (ERS), which activates the unfolded protein response (UPR) for proteostasis. Since both RFR exposure and ERS can cause male infertility, we hypothesized that RFR exposure causes ERS to adversely affect testicular functions in rats. To investigate role of ERS in mediating RFR effects on rat testis, we established five experimental groups in male rats: control, short-term 2100-megahertz (MHz) RFR (1-week), short-term sham (sham/1-week), long-term 2100-MHz RFR (10-week), and long-term sham (sham/10-week). ERS markers Grp78 and phosphorylated PERK (p-Perk) levels and ERS-related apoptosis markers Chop and caspase 12 were investigated by immunohistochemistry, immunoblotting, and quantitative real-time polymerase chain reaction (qPCR). Long-term RFR exposure increased Grp78, p-Perk, and Chop levels, while short-term RFR exposure elevated Chop and caspase 12 levels. Chop expression was not observed in spermatogonia and primary spermatocytes, which may protect spermatogonia and primary spermatocytes against RFR-induced ERS-mediated apoptosis, thereby allowing transmission of genetic material to next generations. While short and long-term RFR exposures trigger ERS and ERS-related apoptotic pathways, further functional analyses are needed to elucidate whether this RFR-induced apoptosis has long-term male infertility effects.

Rotenone-induced cell apoptosis via endoplasmic reticulum stress and PERK-eIF2α-CHOP signalling pathways in TM3 cells

Rotenone (ROT), a widely used natural pesticide, has an uncertain effect on reproductive toxicity. In this study, we used 20 mice distributed randomly into four groups, with each group receiving ROT doses of 0, 2, 4, and 8 mg/kg/day for 28 days. The results demonstrated that ROT induced significant testicular damage, including impaired spermatogenesis, inhibition of testosterone synthesis, and apoptosis of Leydig cells. Additionally, ROT disrupted the normal ultrastructure of the endoplasmic reticulum (ER) in testicular tissue, leading to ER stress in Leydig cells. To further explore whether ROT-induced apoptosis in Leydig cells is related to ER stress, the mouse Leydig cell line (TM3 cells) was treated with ROT at 0, 250, 500, and 1000 nM. ROT inhibited TM3 cell viability, induced cytotoxicity, and reduced testosterone content in the culture supernatants. Furthermore, ROT treatment triggered apoptosis in TM3 cells by activating ER stress and the PERK-eIF2α-CHOP signalling pathway. Pre-treatment of TM3 cells exposed to ROT with the ER stress inhibitor 4-phenylbutyric acid (4-PBA) alleviated these effects, decreasing apoptosis and preserving testosterone levels. Further intervention with the PERK inhibitor GSK2606414 reduced ROT-induced apoptosis and testosterone reduction by inhibiting PERK activity. In summary, ROT-induced male reproductive toxicity is specifically driven by apoptosis, with the PERK-eIF2α-CHOP signalling pathway activated by ER stress playing a crucial role in the apoptosis of Leydig cells triggered by ROT.

PKD regulates mitophagy to prevent oxidative stress and mitochondrial dysfunction during mouse oocyte maturation

Mitochondria play dominant roles in various cellular processes such as energy production, apoptosis, calcium homeostasis, and oxidation-reduction balance. Maintaining mitochondrial quality through mitophagy is essential, especially as its impairment leads to the accumulation of dysfunctional mitochondria in aging oocytes. Our previous research revealed that PKD expression decreases in aging oocytes, and its inhibition negatively impacts oocyte quality. Given PKD's role in autophagy mechanisms, this study investigates whether PKD regulates mitophagy to maintain mitochondrial function and support oocyte maturation. When fully grown oocytes were treated with CID755673, a potent PKD inhibitor, we observed meiosis arrest at the metaphase I stage, along with decreased spindle stability. Our results demonstrate an association with mitochondrial dysfunction, including reduced ATP production and fluctuations in Ca2+ homeostasis, which ultimately lead to increased ROS accumulation, stimulating oxidative stress-induced apoptosis and DNA damage. Further research has revealed that these phenomena result from PKD inhibition, which affects the phosphorylation of ULK, thereby reducing autophagy levels. Additionally, PKD inhibition leads to decreased Parkin expression, which directly and negatively affects mitophagy. These defects result in the accumulation of damaged mitochondria in oocytes, which is the primary cause of mitochondrial dysfunction. Taken together, these findings suggest that PKD regulates mitophagy to support mitochondrial function and mouse oocyte maturation, offering insights into potential targets for improving oocyte quality and addressing mitochondrial-related diseases in aging females.

Identification of potential phytochemicals and their inhibitory effect on the PERK receptor mediated UPR pathway for neuronal disease regulation: an in silico insight

The endoplasmic reticulum (ER) has been considered as the key site of protein biosynthesis and maturation in the eukaryotic cell. In recent years, the sequence at the N-terminal region of translated protein has shown a particular emphasis as a signal responsible for site-specific translocation mediated by post-translational modification. Once the native conformation is not achieved, the degradation pathway is activated, and therefore the restoration of the homeostasis of ER function in UPR pathway is initiated. One of the transmembrane proteins, PKR-like ER kinase (PERK) plays a key role in the activation of UPR through the inhibition of the translation process, thus preventing the cells from apoptosis due to chronic ER stress. Dysregulation of the neuronal proteostasis often results in neuronal dysfunction and its crucially associated neurodegenerative diseases or its manifestation of neuropathic pain. The correlation between ER stress and its associated signaling cascade, namely UPR, is well established in context of neuropathological modifications. This furthermore suggests that the proteins of the signaling cascade such as PERK can serve as a potential target during the onset of neuronal damage. The aim of this study was to identify the potential phytocompounds by evaluating the physicochemical properties, Lipinski screening, ADMET and toxicity properties of the selected phytocompounds by using SwissADME, MolInspiration and pKCSM webservers, which could establish a comparatively better affinity and binding energy than the control drug as GSK2606414 in set up the treatment of the neuronal diseases through molecular docking via PyRx and validating their structural stability through simulation using the Sybyl software for over100ns.Communicated by Ramaswamy H. Sarma.

Impact of DEHP on mitochondria-associated endoplasmic reticulum membranes and reproductive toxicity in ovary

Di(2-ethylhexyl) phthalate (DEHP) is a widely recognized environmental endocrine disruptor that potentially impacts female reproductive function, although the specific mechanisms leading to such impairment remain unclear. A growing body of research has revealed that the endoplasmic reticulum and mitochondrial function significantly influence oocyte quality. The structure of mitochondria-associated endoplasmic reticulum membranes (MAMs) is crucial for facilitating the exchange of Ca2+, lipids, and metabolites. This study aimed to investigate the alterations in the composition and function of MAMs after DEHP exposure and to elucidate the underlying mechanisms of ovarian toxicity. The female mice were exposed to DEHP at doses of 5 and 500 mg/kg/day for one month. The results revealed that DEHP exposure led to reduced serum anti-Müllerian hormone levels and increased atretic follicles in mice. DEHP induced endoplasmic reticulum stress and disrupted calcium homeostasis in oocytes. Furthermore, DEHP impaired the mitochondrial function of oocytes and reduced their membrane potential, and promoting apoptosis. Similar results were observed in human granulosa cells after exposure to mono-(2-ethylhexyl) phthalate (MEHP, metabolites of DEHP) in vitro. Proteomic analysis and transmission electron microscopy revealed modifications in the functional proteins and structure of the MAMs, and the suppression of oxidative phosphorylation pathways. The findings of this investigation provide a new perspective on the mechanism underlying the reproductive toxicity of DEHP in females.

Usnic acid alleviates testicular ischemia/reperfusion injury in rats by modulating endoplasmic reticulum stress

Testicular torsion (TT) is a urological condition that can result in infertility in men. The etiopathogenesis of TT includes ischemia/reperfusion injury (IRI) characterized by oxidative stress (OS), inflammation and apoptosis resulting from increased levels of free radicals. Usnic acid (UA), a dibenzofuran, is one of the most common metabolites found in lichens and is known to possess powerful antioxidant properties. The aim of this study was to investigate the potential protective activity of UA in an experimental testicular IRI model for the first time. A total of 18 rats were randomly assigned to three groups (n=6): sham control, IRI and IRI+UA. The IRI groups underwent a four-hour period of ischemia and a two-hour period of reperfusion. The OS, inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in testicular tissue were evaluated using colorimetric methods. Furthermore, tissue samples were subjected to histological examination, with staining using hematoxylin and eosin. Histopathological findings supported by increased OS, inflammation, ERS and apoptosis levels were obtained in IRI group compared with sham control group. However, UA treatment restored these pathological and biochemical changes. Although this study provides the first preliminary evidence that UA may be used as a useful molecule against testicular IRI, further extensive molecular preclinical studies should be performed before clinical use is considered.

Effect of astaxanthin supplementation on female fertility and reproductive outcomes: a systematic review and meta-analysis of clinical and animal studies

CONTEXT

Oxidative stress (OS) plays a harmful role in female reproduction and fertility. Several studies explored various dietary interventions and antioxidant supplements, such as astaxanthin (AST), to mitigate the adverse effects of OS on female fertility. Ameliorative effects of AST on female fertility and the redox status of reproductive organs have been shown in several animal and clinical studies.

OBJECTIVES

The main objective of present systematic review and meta-analysis of both animal and clinical studies was to provide a comprehensive overview of the current evidence on the effects of AST on female fertility and reproductive outcomes. The effect of AST on redox status, inflammatory and apoptotic markers in reproductive organs were included as the secondary outcomes.

DATA SOURCES

We systematically searched electronic databases including PubMed, Scopus, and Web of Science, until January 1, 2024, using specified search terms related to AST, female reproductive performance, and infertility, considering the diverse synonyms found in the literature for interventional studies that compared oral AST supplementation with placebo or control in human or animal models.

DATA EXTRACTION

Two independent reviewers extracted data on study characteristics, outcomes, and risk of bias. We pooled the results using random-effects models and assessed the heterogeneity and quality of evidence. We descriptively reported the data from animal models, as meta-analysis was not possible.

DATA ANALYSIS

The meta-analysis of clinical trials showed that AST significantly increased the oocyte maturation rate (MD: 8.40, 95% CI: 4.57 to 12.23, I2: 0%) and the total antioxidant capacity levels in the follicular fluid (MD: 0.04, 95% CI: 0.02 to 0.06, I2: 0%). The other ART and pregnancy outcomes and redox status markers did not show statistically significant changes. The animal studies reported ameliorative effects of AST on redox status, inflammation, apoptosis, and ovarian tissue histomorphology.

CONCLUSION

This systematic review shows that AST supplementation may improve assisted reproductive technology outcomes by enhancing oocyte quality and reducing OS in the reproductive organs. However, the evidence is limited by the heterogeneity, risk of bias, and small sample size of the included studies.

Isorhamnetin Improves Oocyte Maturation by Activating the Pi3k/Akt Signaling Pathway

SCOPE

Isorhamnetin is a natural flavonoid with various pharmacological activities, which can be widely and continuously ingested by humans and animals through their daily diet. The aim of this study is to explore the benefits and molecular mechanisms of isorhamnetin on oocyte maturation.

METHODS AND RESULTS

Oocytes are incubated with isorhamnetin (5, 10, 20, and 30 µM) for 44 h. Isorhamnetin (10 µM) increases the polar body extrusion rate of oocytes. Furthermore, isorhamnetin alleviates oxidative stress by inhibiting reactive oxygen species levels and stimulating SOD2 protein expression. The changes in intracellular mitochondrial autophagy and apoptosis-related proteins (Bcl-2, Bax/Bcl-2, and C-Casp3) indicate that isorhamnetin inhibits oocyte apoptosis. Isorhamnetin inhibits endoplasmic reticulum stress by reducing the protein expression of CHOP and GRP78 and improving the normal distribution rate of endoplasmic reticulum. Mechanistic studies show that isorhamnetin activates the PI3K/Akt signaling pathway.

CONCLUSION

Isorhamnetin promotes oocyte maturation by inhibiting oxidative stress, mitochondrial dysregulation, apoptosis, and endoplasmic reticulum stress, which have important potential for improving oocyte quality and treating female infertility.

Exploring the causal effect of placental physiology in susceptibility to mental and addictive disorders: a Mendelian randomization study

Background

Epidemiological studies have linked low birth weight to psychiatric disorders, including substance use disorders. Genomic analyses suggest a role of placental physiology on psychiatric risk. We investigated whether this association is causally related to impaired trophoblast function.

Methods

We conducted a two-sample summary-data Mendelian randomization study using as instrumental variables those genetic variants strongly associated with birth weight, whose effect is exerted through the fetal genome, and are located near genes with differential expression in trophoblasts. Eight psychiatric and substance use disorders with >10,000 samples were included as outcomes. The inverse variance weighted method was used as the main analysis and several sensitivity analyses were performed for those significant results.

Results

The inverse variance weighted estimate, based on 14 instrumental variables, revealed an association, after correction for multiple tests, between birth weight and broadly defined depression (β = -0.165, 95% CI = -0.282 to -0.047, P = 0.0059). Sensitivity analyses revealed the absence of heterogeneity in the effect of instrumental variables, confirmed by leave-one-out analysis, MR_Egger intercept, and MR_PRESSO. The effect was consistent using robust methods. Reverse causality was not detected. The effect was specifically linked to genetic variants near genes involved in trophoblast physiology instead of genes with fetal effect on birth weight or involved in placenta development.

Conclusion

Impaired trophoblast functioning, probably leading to reduced fetal brain oxygen and nutrient supply, is causally related to broadly defined depression. Considering the therapeutic potential of some agents to treat fetal growth restriction, further research on the effect of trophoblast physiology on mental disorders may have future implications in prevention.

LIM homeobox 1 (LHX1) induces endoplasmic reticulum stress and promotes preterm birth

Background

Premature birth (PTB) is a major cause of neonatal mortality and has enduring consequences. LIM Homeobox 1 (LHX1) is vital in embryonic organogenesis, while Inositol-Requiring Enzyme 1 (IRE-1) regulates endoplasmic reticulum stress (ERS). This study explores whether IRE-1 impacts PTB via LHX1 modulation.

Methods

We analyzed LHX1 expression in placental samples from PTB patients and examined its impact on the viability, migration, invasion, and apoptosis of the human placental trophoblast cell line HTR8/Svneo, particularly when treated with the ERS inducer tunicamycin (TM). We also assessed the levels of ERS-related genes and autophagy activation in response to LHX1 deficiency. To gain mechanistic insights, we evaluated the ERS-mediated activation of the IRE-1/XBP1/CHOP signaling pathway in LHX1-silenced HTR8/Svneo cells. Additionally, we examined the transcriptional activation of IRE-1 and the binding of LHX1 to the IRE-1 promoter in HTR8/Svneo cells. We overexpressed IRE-1 in LHX1-silenced HTR8/Svneo cells to assess its effects on cell viability, migration, invasion, apoptosis, and autophagy. Finally, we induced LHX1 knockdown in mice through intraperitoneal injections of tunicamycin (TM) and Sh-LHX1 over a 24-h period to evaluate PTB symptoms.

Results

We observed LHX1 overexpression in placental tissue from PTB cases and TM-induced HTR8/Svneo cells. LHX1 depletion enhanced cell viability, migration, and invasion while reducing autophagy and apoptosis. This reduction in LHX1 led to decreased levels of IRE-1, XBP1, CHOP, and other ERS-related genes, indicating LHX1's role in ERS induction and the activation of the IRE-1/XBP1/CHOP pathway. Mechanistically, LHX1 was found to bind to the IRE-1 promoter, inducing its transcriptional activation. Notably, overexpressing IRE-1 counteracted the impact of LHX1 depletion on trophoblast cell behavior, suggesting that LHX1 modulates IRE-1. In line with our in vitro studies, LHX1 knockdown ameliorated PTB symptoms in TM-treated mice.

Conclusion

LHX1 contributes to the progression of PTB by regulating the IRE-1-XBP1-CHOP pathway.

Berberine alleviates ovarian tissue damage in mice with hepatolenticular degeneration by suppressing ferroptosis and endoplasmic reticulum stress

OBJECTIVE

Hepatolenticular degeneration (HLD) is an autosomal recessive disorder that manifests as multiorgan damage due to impaired copper (Cu) metabolism. Female patients with HLD often experience reproductive impairments. This study investigated the protective effect of berberine against ovarian damage in toxic-milk (TX) mice, a murine model for HLD.

METHODS

Mice were categorized into control group, HLD TX group (HLD group), penicillamine (Cu chelator)-treated TX group and berberine-treated TX group. Body weight, ovary weight and the number of ovulated eggs were recorded. Follicular morphology and cellular ultrastructure were examined. Total iron, ferrous iron (Fe2+) and trivalent iron (Fe3+) levels, as well as malondialdehyde (MDA), glutathione (GSH) and oxidized glutathione (GSSG), were measured in the ovaries. Western blot analysis was used to analyze the expression of proteins related to ferroptosis and endoplasmic reticulum (ER) stress.

RESULTS

Ovarian tissue damage was evident in the HLD group, with a significant increase in ferroptosis and ER stress compared to the control group. This damage was inhibited by treatment with penicillamine, a Cu chelator. Compared with the HLD group, berberine increased the number of ovulations, and improved ovarian morphology and ultrastructure. Further, we found that berberine reduced total iron, Fe2+, MDA and GSSG levels, elevated GSH levels, decreased the expression of the ferroptosis marker protein prostaglandin-endoperoxide synthase 2 (PTGS2), and increased glutathione peroxidase 4 (GPX4) expression. Furthermore, berberine inhibited the expression of ER stress-associated proteins mediated by the protein kinase RNA-like ER kinase (PERK) pathway.

CONCLUSION

Ferroptosis and ER stress are involved in Cu-induced ovarian damage in TX mice. Berberine ameliorates ovarian damage in HLD TX mice by inhibiting ferroptosis and ER stress. Please cite this article as: Liu QZ, Han H, Fang XR, Wang LY, Zhao D, Yin MZ, Zhang N, Jiang PY, Ji ZH, Wu LM. Berberine alleviates ovarian tissue damage in mice with hepatolenticular degeneration by suppressing ferroptosis and endoplasmic reticulum stress. J Integr Med. 2024; 22(4): 494-503.

The Effects of Ketogenic Diet on Brain Gene Expressions in Type 2 Diabetes Background

Type 2 diabetes mellitus (T2DM) is a major risk factor of a number of neurodegenerative diseases (NDDs). Ketogenic diet (KD) has significant beneficial effects on glycemic control and may act effectively against NDDs, but the mechanism remains unclear. In this study, we aimed to investigate the potential effects of KD on gene expressions in the brains of T2DM model mice. Male db/db mice at the age of 9 weeks were fed with KD or normal diet to the age of 6 months, and the whole brains were subjected to mRNA-seq analysis for differentially expressed genes. KD significantly lowered fasting glucose and body weights in db/db mice (P < 0.05), and the expression of 189 genes in the brain were significantly changed (P < 0.05, |log2| > 1). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the differentially expressed genes upon KD are involved in inflammatory responses and the functions of biosynthesis. In inflammatory responses, NF-κB signaling pathway, viral protein interaction with cytokine and cytokine receptor, and cytokine-cytokine receptor interaction pathways were enriched, and in biosynthesis pathways, genes functioning in lipid and amino acid metabolism, protein synthesis, and energy metabolism were enriched. Moreover, consistent with the gene set enrichment analysis results, proteasomal activity measured biochemically were enhanced in KD-fed T2DM mice. These data may facilitate the understanding of how KD can be protective to the brain in T2DM background. KD could be a new strategy for the prevention of NDDs in T2DM patients.

Sex-biased regulatory changes in the placenta of native highlanders contribute to adaptive fetal development

Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared the transcriptome and histology of full-term placentas between native Tibetans and Han migrants. We found that the placental trophoblast shows the largest expression divergence between Tibetans and Han, and Tibetans show decreased immune response and endoplasmic reticulum stress. Remarkably, we detected a sex-biased expression divergence, where the male-infant placentas show a greater between-population difference than the female-infant placentas. The umbilical cord plays a key role in the sex-biased expression divergence, which is associated with the higher birth weight of the male newborns of Tibetans. We also identified adaptive histological changes in the male-infant placentas of Tibetans, including larger umbilical artery wall and umbilical artery intima and media, and fewer syncytial knots. These findings provide valuable insights into the sex-biased adaptation of human populations, with significant implications for medical and genetic studies of human reproduction.

Crosstalk between protein misfolding and endoplasmic reticulum stress during ageing and their role in age-related disorders

Maintaining the proteome is crucial to retaining cell functionality and response to multiple intrinsic and extrinsic stressors. Protein misfolding increased the endoplasmic reticulum (ER) stress and activated the adaptive unfolded protein response (UPR) to restore cell homeostasis. Apoptosis occurs when ER stress is prolonged or the adaptive response fails. In healthy young cells, the ratio of protein folding machinery to quantities of misfolded proteins is balanced under normal circumstances. However, the age-related deterioration of the complex systems for handling protein misfolding is accompanied by ageing-related disruption of protein homeostasis, which results in the build-up of misfolded and aggregated proteins. This ultimately results in decreased cell viability and forms the basis of common age-related diseases called protein misfolding diseases. Proteins or protein fragments convert from their ordinarily soluble forms to insoluble fibrils or plaques in many of these disorders, which build up in various organs such as the liver, brain, or spleen. Alzheimer's, Parkinson's, type II diabetes, and cancer are diseases in this group commonly manifest in later life. Thus, protein misfolding and its prevention by chaperones and different degradation paths are becoming understood from molecular perspectives. Proteodynamics information will likely affect future interventional techniques to combat cellular stress and support healthy ageing by avoiding and treating protein conformational disorders. This review provides an overview of the diverse proteostasis machinery, protein misfolding, and ER stress involvement, which activates the UPR sensors. Here, we will discuss the crosstalk between protein misfolding and ER stress and their role in developing age-related diseases.

Tris(2-ethylhexyl) phosphate induces cytotoxicity in TM3 Leydig cells by modulating autophagy and endoplasmic reticulum stress

Tris (2-ethylhexyl) phosphate (TEHP) is a frequently used organophosphorus flame retardant with significant ecotoxicity and widespread human exposure. Recent research indicates that TEHP has reproductive toxicity. However, the precise cell mechanism is not enough understood. Here, by using testicular mesenchymal stromal TM3 cells as a model, we reveal that TEHP induces apoptosis. Then RNA sequencing analysis, immunofluorescence, and western blotting results show that THEP inhibits autophagy flux and enhances endoplasmic reticulum (ER) stress. Moreover, the activation of the ER stress is critical for TEHP-induced cell injury. Interestingly, TEHP-induced ER stress is contributed to autophagic flux inhibition. Furthermore, pharmacological inhibition of autophagy aggravates, and activation of autophagy attenuates TEHP-induced apoptosis. In summary, these findings indicate that TEHP triggers apoptosis in mouse TM3 cells through ER stress activation and autophagy flux inhibition, offering a new perspective on the mechanisms underlying TEHP-induced interstitial cytotoxicity in the mouse testis.

Aluminum exposure impairs oocyte quality via subcellular structure disruption and DNA damage-related apoptosis in mice

Aluminum (Al) can lead to an exposure of creature in varieties ways for its universality, and it could disturb normal physiological metabolism, with the damage to multisystem including reproduction. Since the oocyte quality is critical for female reproduction, we inspected the toxicity of Al on mouse oocyte maturation. We constructed in vitro exposure mouse model, and we found that 5 mmol/L Al had adverse effects on oocyte maturation by impairing organelle and cytoskeleton. Aberrant spindle and misaligned chromosomes which might be considered to be caused by elevated levels of acetylation, as well as abnormal distribution of actin dynamics could hinder normal meiosis of oocytes. Organelle dysfunction indicated that Al affected proteins synthesis, transport and digestion, which would further damage oocyte maturation. In order to explore the mechanism of Al toxicity, our further investigation demonstrated that Al caused mitochondrial dysfunction and imbalance calcium homeostasis, resulting in limited energy supply. Moreover, high level of reactive oxygen species, DNA damage and apoptosis caused by oxidative stress were also the manifestation of Al toxicity on oocytes. In conclusion, our study provided the evidence that Al exposure affected oocyte quality through its effects on spindle organization, actin dynamics, organelle function and the induction of DNA damage-related apoptosis with mouse model.

Chromatin Modifier EP400 Regulates Oocyte Quality and Zygotic Genome Activation in Mice

Epigenetic modifiers that accumulate in oocytes, play a crucial role in steering the developmental program of cleavage embryos and initiating life. However, the identification of key maternal epigenetic regulators remains elusive. In the findings, the essential role of maternal Ep400, a chaperone for H3.3, in oocyte quality and early embryo development in mice is highlighted. Depletion of Ep400 in oocytes resulted in a decline in oocyte quality and abnormalities in fertilization. Preimplantation embryos lacking maternal Ep400 exhibited reduced major zygotic genome activation (ZGA) and experienced developmental arrest at the 2-to-4-cell stage. The study shows that EP400 forms protein complex with NFYA, occupies promoters of major ZGA genes, modulates H3.3 distribution between euchromatin and heterochromatin, promotes transcription elongation, activates the expression of genes regulating mitochondrial functions, and facilitates the expression of rate-limiting enzymes of the TCA cycle. This intricate process driven by Ep400 ensures the proper execution of the developmental program, emphasizing its critical role in maternal-to-embryonic transition.

Relationship Between Recurrent Pregnancy Loss With Unknown Etiology and Endoplasmic Reticulum Stress

INTRODUCTION

Recurrent pregnancy loss (RPL) is characterized by consecutive pregnancy losses before 20 weeks of gestation, with evolving definitions necessitating adjustments to prevent delays in couples' evaluation. Limited etiological data on RPL prompts comprehensive evaluations, often yielding no pathological findings. Emerging research implicates endoplasmic reticulum (ER) stress in various reproductive processes, yet its association with RPL remains understudied.

AIM

To evaluate ER stress in patients with RPL with unknown etiology by determining the plasma concentration of X-box binding protein-1 (XBP-1).

MATERIALS AND METHODS

A total of 45 patients aged 18 to 35 years with at least two pregnancy losses with unknown etiology before the completion of 20 weeks of gestation between March 2020 and September 2020 were included in the study group. The control group consisted of 45 healthy women with at least two previous live births, no pregnancy-associated complications, and no history of pregnancy loss or infertility. The XBP-1 levels were determined from serum samples. Statistical analyses assessed differences between groups, and receiver operating characteristic (ROC) curve analysis determined XBP-1's predictive value for RPL.

RESULTS

The mean XBP-1 concentration in the RPL group was significantly higher than in the control group (p < 0.001). The mean values were 2243.65 ± 9425.27 pg/mL and 1196.32 ± 4378.81 pg/mL, respectively. The use of XBP-1 levels for the prediction of RPL was evaluated. In an ROC curve analysis, the area under the curve was found to be 87% (95% CI: 80% to 94.8%). The specificity was 78%, the sensitivity was 88%, the positive likelihood ratio (LR) was 4, the negative LR was 0.15, the positive predictive value was 80%, and the negative predictive value was 87% for the cut-off XBP-1 level at 1364.68 pg/mL.

CONCLUSION

This study highlights the potential role of ER stress in RPL and proposes XBP-1 as a predictive biomarker for pregnancy loss. Understanding ER stress mechanisms in RPL could inform diagnostic and therapeutic strategies. Further research is essential to validate these findings and explore their clinical implications.

PBA alleviates cadmium-induced mouse spermatogonia apoptosis by suppressing endoplasmic reticulum stress

OBJECTIVE

Endoplasmic reticulum (ER) stress mediates Cd-caused germ cell apoptosis in testis. The effects of 4-phenylbutyric acid (PBA), a classical chaperone, were investigated on Cd-induced apoptosis in mouse GC-1 spermatogonia cells.

METHODS

The cells were pretreated with PBA before Cd exposure. TUNEL and flow cytometry assays were applied to determine apoptosis. Some key biomarkers of ER stress were analyzed using RT-PCR and western blot.

RESULTS

as expected, the apoptotic cells exposed to Cd apparently increased. The mRNA and protein expression levels of GRP78 and ATF6α, were elevated in the Cd groups. Additional experiments displayed that Cd notably increased IRE1α and JNK phosphorylation, and upregulated XBP-1 mRNA and protein expression. Moreover, p-eIF2α and CHOP expressions were clearly elevated in the Cd groups. Interestingly, PBA almost completely inhibited ER stress and protected spermatogonia against apoptosis induced by Cd.

CONCLUSION

PBA alleviated Cd-induced ER stress and spermatogonia apoptosis, and may have the therapeutic role in Cd-induced male reproductive toxicity.

Transcriptomics analysis of the bovine endometrium during the perioestrus period

During the oestrous cycle, the bovine endometrium undergoes morphological and functional changes, which are regulated by alterations in the levels of oestrogen and progesterone and consequent changes in gene expression. To clarify these changes before and after oestrus, RNA-seq was used to profile the transcriptome of oestrus-synchronized beef heifers. Endometrial samples were collected from 29 animals, which were slaughtered in six groups beginning 12 h after the withdrawal of intravaginal progesterone releasing devices until seven days post-oestrus onset (luteal phase). The groups represented proestrus, early oestrus, metoestrus and early dioestrus (luteal phase). Changes in gene expression were estimated relative to gene expression at oestrus. Ingenuity Pathway Analysis (IPA) was used to identify canonical pathways and functional processes of biological importance. A total of 5,845 differentially expressed genes (DEGs) were identified. The lowest number of DEGs was observed at the 12 h post-oestrus time point, whereas the greatest number was observed at Day 7 post-oestrus onset (luteal phase). A total of 2,748 DEGs at this time point did not overlap with any other time points. Prior to oestrus, Neurological disease and Organismal injury and abnormalities appeared among the top IPA diseases and functions categories, with upregulation of genes involved in neurogenesis. Lipid metabolism was upregulated before oestrus and downregulated at 48h post-oestrus, at which point an upregulation of immune-related pathways was observed. In contrast, in the luteal phase the Lipid metabolism and Small molecule biochemistry pathways were upregulated.

Perfluorooctanoic acid induces Leydig cell injury via inhibition of autophagosomes formation and activation of endoplasmic reticulum stress

Perfluorooctanoic acid (PFOA) is a man-made chemical broadly distributed in various ecological environment and human bodies, which poses potential health risks. Its toxicity, especially the male reproduction toxicity has drawn increasing attention due to declining birth rates in recent years. However, how PFOA induces male reproductive toxicity remains unclear. Here, we characterize PFOA-induced cell injury and reveal the underlying mechanism in mouse Leydig cells, which are critical to spermatogenesis in the testes. We show that PFOA induces cell injury as evidenced by reduced cell viability, cell morphology changes and apoptosis induction. RNA-sequencing analysis reveals that PFOA-induced cell injury is correlated with compromised autophagy and activated endoplasmic reticulum (ER) stress, two conserved biological processes required for regulating cellular homeostasis. Mechanistic analysis shows that PFOA inhibits autophagosomes formation, and activation of autophagy rescues PFOA-induced apoptosis. Additionally, PFOA activates ER stress, and pharmacological inhibition of ER stress attenuates PFOA-induced cell injury. Taken together, these results demonstrate that PFOA induces cell injury through inhibition of autophagosomes formation and induction of ER stress in Leydig cells. Thus, our study sheds light on the cellular mechanisms of PFOA-induced Leydig cell injury, which may be suggestive to human male reproductive health risk assessment and prevention from PFOA exposure-induced reproductive toxicity.

Inhibition of the endoplasmic reticulum stress-associated IRE-1 pathway alleviates preterm birth

BACKGROUND

Premature birth (PTB) remains a major global health concern due to its association with neonatal morbidity and mortality. The unfolded protein response (UPR) within the endoplasmic reticulum (ER) is tightly regulated by Inositol-requiring enzyme type 1 (IRE-1), a pivotal cellular modulator. This study seeks to elucidate the role of the ER stress (ERS)-related IRE-1 pathway in PTB.

METHODS

Human placental trophoblast cells HTR8/Svneo were exposed to the ER-stress inducer tunicamycin (TM). The expression of IRE-1 and ERS-associated proteins ATF6, GRP78, and XBP-1 was assessed in placental tissues and TM-treated cells. Cellular viability, migration, invasion, and apoptosis were evaluated through a series of experimental assays. Additionally, various methods were employed to assess and verify the activation of autophagy, using the autophagy marker, microtubule-associated protein 1A/1B-light chain 3 (LC3). Additionally, TUDCA (an ERS inhibitor) was used to assess its potential to counteract the TM-induced cell effects.

RESULTS

Elevated levels of ATF6, GRP78, and XBP-1 were observed in PTB tissues and cells. TM treatment substantially reduced cell viability, migration, and invasion while promoting apoptosis. Treatment with TUDCA (an ERS inhibitor) counteracted the effects of TM on the cells. Furthermore, we identified an overexpression of IRE-1 in PTB tissues and cells and its knockdown enhanced cell viability, migration, and invasion while suppressed apoptosis and autophagy under TM stimulation. Notably, IRE-1 was found to modulate the activity of the IRE-1/XBP1/CHOP signaling pathway in TM-treated cells.

CONCLUSION

The upregulation of IRE-1 in PTB placental tissues is implicated in the pathogenesis of PTB. Importantly, inhibiting the ERS-associated IRE-1/XBP1/CHOP pathway may be a good strategy in mitigating PTB.

Surfeit locus protein 4 modulates endoplasmic reticulum function and maintains oocyte quality

Surfeit locus protein 4 is a cargo receptor mediating cargo transport from the endoplasmic reticulum lumen to the Golgi apparatus. Loss of Surf4 gene led to embryonic lethality in mice. However, the role of Surf4 during oocyte development remains unknown. In this study, we generated the mouse model with oocyte-specific knockout of Surf4 gene. We found that adult mice with deletion of Surf4 showed normal folliculogenesis, ovulation and fertility. However, loss of Surf4 slightly impaired oocyte quality, thus led to partial oocyte meiotic arrest and reduced ratio of blastocyst formation. Consistent with this, the distribution of endoplasmic reticulum was disturbed in Surf4-deficient oocytes in mice. These results demonstrated that although Surf4 is dispensable for female mouse fertility, Surf4 modulates endoplasmic reticulum arrangement and participates in regulation of developmental competence of oocytes.

Nitric oxide-induced endoplasmic reticulum stress of Schistosoma japonicum inhibits the worm development in rats

Schistosomiasis, caused by Schistosoma spp., is a zoonotic parasitic disease affecting human health. Rattus norvegicus (rats) are a non-permissive host of Schistosoma, in which the worms cannot mature and cause typical egg granuloma. We previously demonstrated that inherent high levels of nitric oxide (NO), produced by inducible NO synthase (iNOS), is a key molecule in blocking the development of S. japonicum in rats. To further explore the mechanism of NO inhibiting S. japonicum development in rats, we performed S-nitrosocysteine proteomics of S. japonicum collected from infected rats and mice. The results suggested that S. japonicum in rats may have undergone endoplasmic reticulum (ER) stress. Interestingly, we found that the ER of S. japonicum in rats showed marked damage, while the ER of the worm in iNOS-/- rats and mice were relatively normal. Moreover, the expression of ER stress markers in S. japonicum from WT rats was significantly increased, compared with S. japonicum from iNOS-/- rats and mice. Using the NO donor sodium nitroprusside in vitro, we demonstrated that NO could induce ER stress in S. japonicum in a dose-dependent manner, and the NO-induced ER stress in S. japonicum could be inhibited by ER stress inhibitor 4-Phenyl butyric acid. We further verified that inhibiting ER stress of S. japonicum in rats promoted parasite development and survival. Furthermore, we demonstrated that NO-induced ER stress of S. japonicum was related to the efflux of Ca2+ from ER and the impairment of mitochondrial function. Collectively, these findings show that high levels of NO in rats could induce ER stress in S. japonicum by promoting the efflux of Ca2+ from ER and damaging the mitochondrial function, which block the worm development. Thus, this study further clarifies the mechanism of anti-schistosome in rats and provides potential strategies for drug development against schistosomiasis and other parasitosis.

Supplementation with Eupatilin during In Vitro Maturation Improves Porcine Oocyte Developmental Competence by Regulating Oxidative Stress and Endoplasmic Reticulum Stress

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is a flavonoid derived from Artemisia plants that has beneficial biological activities, such as anti-apoptotic, anti-oxidant, and anti-inflammatory activities. However, the protective effects of eupatilin against oxidative stress and endoplasmic reticulum stress in porcine oocyte maturation are still unclear. To investigate the effect of eupatilin on the development of porcine oocytes after in vitro maturation and parthenogenetic activation, we added different concentrations of eupatilin in the process of porcine oocyte maturation in vitro, and finally selected the optimal concentration following multiple comparisons and analysis of test results using SPSS (version 17.0; IBM, Chicago, IL, USA) software. The results showed that 0.1 μM eupatilin supplementation did not affect the expansion of porcine cumulus cells, but significantly increased the extrusion rate of porcine oocyte polar bodies, the subsequent blastocyst formation rate, and the quality of parthenogenetically activated porcine embryos. Additionally, it reduced the level of reactive oxygen species in cells and increased glutathione production. Further analysis revealed that eupatilin supplementation could reduce apoptosis, DNA double-strand breaks, and endoplasmic reticulum stress. In conclusion, supplementation with 0.1 μM eupatilin during in vitro maturation improved oocyte maturation and subsequent embryo development by reducing oxidative stress and endoplasmic reticulum stress.

Diabetes-induced male infertility: potential mechanisms and treatment options

Male infertility is a physiological phenomenon in which a man is unable to impregnate a fertile woman during a 12-month period of continuous, unprotected sexual intercourse. A growing body of clinical and epidemiological evidence indicates that the increasing incidence of male reproductive problems, especially infertility, shows a very similar trend to the incidence of diabetes within the same age range. In addition, a large number of previous in vivo and in vitro experiments have also suggested that the complex pathophysiological changes caused by diabetes may induce male infertility in multiple aspects, including hypothalamic-pituitary-gonadal axis dysfunction, spermatogenesis and maturation disorders, testicular interstitial cell damage erectile dysfunction. Based on the above related mechanisms, a large number of studies have focused on the potential therapeutic association between diabetes progression and infertility in patients with diabetes and infertility, providing important clues for the treatment of this population. In this paper, we summarized the research results of the effects of diabetes on male reproductive function in recent 5 years, elaborated the potential pathophysiological mechanisms of male infertility induced by diabetes, and reviewed and prospected the therapeutic measures.

A Probiotic Bacillus amyloliquefaciens D-1 Strain Is Responsible for Zearalenone Detoxifying in Coix Semen

Zearalenone (ZEN) is a mycotoxin produced by Fusarium spp., which commonly and severely contaminate food/feed. ZEN severely affects food/feed safety and reduces economic losses owing to its carcinogenicity, genotoxicity, reproductive toxicity, endocrine effects, and immunotoxicity. To explore efficient methods to detoxify ZEN, we identified and characterized an efficient ZEN-detoxifying microbiota from the culturable microbiome of Pseudostellaria heterophylla rhizosphere soil, designated Bacillus amyloliquefaciens D-1. Its highest ZEN degradation rate reached 96.13% under the optimal condition. And, D-1 can almost completely remove ZEN (90 μg·g-1) from coix semen in 24 h. Then, the D-1 strain can detoxify ZEN to ZEM, which is a new structural metabolite, through hydrolyzation and decarboxylation at the ester group in the lactone ring and amino acid esterification at C2 and C4 hydroxy. Notably, ZEM has reduced the impact on viability, and the damage of cell membrane and nucleus DNA and can significantly decrease the cell apoptosis in the HepG2 cell and TM4 cell. In addition, it was found that the D-1 strain has no adverse effect on the HepG2 and TM4 cells. Our findings can provide an efficient microbial resource and a reliable reference strategy for the biological detoxification of ZEN.

Chinese herbal medicine and active ingredients for diabetic cardiomyopathy: molecular mechanisms regulating endoplasmic reticulum stress

Background: Diabetic cardiomyopathy (DCM) is one of the serious microvascular complications of diabetes mellitus. It is often associated with clinical manifestations such as arrhythmias and heart failure, and significantly reduces the quality of life and years of survival of patients. Endoplasmic reticulum stress (ERS) is the removal of unfolded and misfolded proteins and is an important mechanism for the maintenance of cellular homeostasis. ERS plays an important role in the pathogenesis of DCM by causing cardiomyocyte apoptosis, insulin resistance, calcium imbalance, myocardial hypertrophy and fibrosis. Targeting ERS is a new direction in the treatment of DCM. A large number of studies have shown that Chinese herbal medicine and active ingredients can significantly improve the clinical outcome of DCM patients through intervention in ERS and effects on myocardial structure and function, which has become one of the hot research directions. Purpose: The aim of this review is to elucidate and summarize the roles and mechanisms of Chinese herbal medicine and active ingredients that have the potential to modulate endoplasmic reticulum stress, thereby contributing to better management of DCM. Methods: Databases such as PubMed, Web of Science, China National Knowledge Internet, and Wanfang Data Knowledge Service Platform were used to search, analyze, and collect literature, in order to review the mechanisms by which phytochemicals inhibit the progression of DCM by targeting the ERS and its key signaling pathways. Keywords used included "diabetic cardiomyopathy" and "endoplasmic reticulum stress." Results: This review found that Chinese herbs and their active ingredients can regulate ERS through IRE1, ATF6, and PERK pathways to reduce cardiomyocyte apoptosis, ameliorate myocardial fibrosis, and attenuate myocardial hypertrophy for the treatment of DCM. Conclusion: A comprehensive source of information on potential ERS inhibitors is provided in this review. The analysis of the literature suggests that Chinese herbal medicine and its active ingredients can be used as potential drug candidates for the treatment of DCM. In short, we cannot ignore the role of traditional Chinese medicine in regulating ERS and treating DCM, and look forward to more research and new drugs to come.

ATF6 aggravates apoptosis in early porcine embryonic development by regulating organelle homeostasis under high-temperature conditions

Activating transcription factor 6 (ATF6), one of the three sensor proteins in the endoplasmic reticulum (ER), is an important regulator of ER stress-induced apoptosis. ATF6 resides in the ER and, upon activation, is translocated to the Golgi apparatus, where it is cleaved by site-1 protease (S1P) to generate an amino-terminal cytoplasmic fragment. Although recent studies have made progress in elucidating the regulatory mechanisms of ATF6, its function during early porcine embryonic development under high-temperature (HT) stress remains unclear. In this study, zygotes were divided into four groups: control, HT, HT+ATF6 knockdown, and HT+PF (S1P inhibitor). Results showed that HT exposure induced ER stress, which increased ATF6 protein expression and led to a decrease in the blastocyst rate. Next, ATF6 expression was knocked down in HT embryos under microinjection of ATF6 double-stranded RNA (dsRNA). Results revealed that ATF6 knockdown (ATF6-KD) attenuated the increased expression of CHOP, an ER stress marker, and Ca 2+ release induced by HT. In addition, ATF6-KD alleviated homeostasis dysregulation among organelles caused by HT-induced ER stress, and further reduced Golgi apparatus and mitochondrial dysfunction in HT embryos. AIFM2 is an important downstream effector of ATF6. Results showed that ATF6-KD reduced the occurrence of AIFM2-mediated embryonic apoptosis at HT. Taken together, our findings suggest that ATF6 is a crucial mediator of apoptosis during early porcine embryonic development, resulting from HT-induced ER stress and disruption of organelle homeostasis.

Mechanisms underlying the role of endoplasmic reticulum stress in the placental injury and fetal growth restriction in an ovine gestation model

BACKGROUND

Exposure to bisphenol A (BPA), an environmental pollutant known for its endocrine-disrupting properties, during gestation has been reported to increase the risk of fetal growth restriction (FGR) in an ovine model of pregnancy. We hypothesized that the FGR results from the BPA-induced insufficiency and barrier dysfunction of the placenta, oxidative stress, inflammatory responses, autophagy and endoplasmic reticulum stress (ERS). However, precise mechanisms underlying the BPA-induced placental dysfunction, and subsequently, FGR, as well as the potential involvement of placental ERS in these complications, remain to be investigated.

METHODS

In vivo experiment, 16 twin-pregnant (from d 40 to 130 of gestation) Hu ewes were randomly distributed into two groups (8 ewes each). One group served as a control and received corn oil once a day, whereas the other group received BPA (5 mg/kg/d as a subcutaneous injection). In vitro study, ovine trophoblast cells (OTCs) were exposed to 4 treatments, 6 replicates each. The OTCs were treated with 400 μmol/L BPA, 400 μmol/L BPA + 0.5 μg/mL tunicamycin (Tm; ERS activator), 400 μmol/L BPA + 1 μmol/L 4-phenyl butyric acid (4-PBA; ERS antagonist) and DMEM/F12 complete medium (control), for 24 h.

RESULTS

In vivo experiments, pregnant Hu ewes receiving the BPA from 40 to 130 days of pregnancy experienced a decrease in placental efficiency, progesterone (P4) level and fetal weight, and an increase in placental estrogen (E2) level, together with barrier dysfunctions, OS, inflammatory responses, autophagy and ERS in type A cotyledons. In vitro experiment, the OTCs exposed to BPA for 24 h showed an increase in the E2 level and related protein and gene expressions of autophagy, ERS, pro-apoptosis and inflammatory response, and a decrease in the P4 level and the related protein and gene expressions of antioxidant, anti-apoptosis and barrier function. Moreover, treating the OTCs with Tm aggravated BPA-induced dysfunction of barrier and endocrine (the increased E2 level and decreased P4 level), OS, inflammatory responses, autophagy, and ERS. However, treating the OTCs with 4-PBA reversed the counteracted effects of Tm mentioned above.

CONCLUSIONS

In general, the results reveal that BPA exposure can cause ERS in the ovine placenta and OTCs, and ERS induction might aggravate BPA-induced dysfunction of the placental barrier and endocrine, OS, inflammatory responses, and autophagy. These data offer novel mechanistic insights into whether ERS is involved in BPA-mediated placental dysfunction and fetal development.