Noncanonical functions of glucocorticoids: A novel role for glucocorticoids in performing multiple beneficial functions in endometrial stem cells

Identification of memory mechanism in tissue-resident stem cells via ANGPTL4 beyond immune cells upon viral antigen exposure

Although memory functions of immune cells characterized by increased resistance to subsequent infections after initial pathogen exposure are well-established, it remains unclear whether non-immune cells, especially tissue-resident stem cells, exhibit similar memory mechanisms. The present study revealed that detrimental effects of initial viral antigen exposure (human papillomavirus [HPV]) on diverse stem cell functions were significantly exacerbated upon subsequent secondary exposure both in vitro and in vivo. Importantly, endometrial stem cells exhibited robust memory functions following consecutive HPV antigen exposures, whereas fully differentiated cells such as fibroblasts and vesicular cells did not show corresponding changes in response to the same antigen exposures. Deficiency of angiopoietin-like 4 (ANGPTL4) achieved through small hairpin RNA knockdown in vitro and knockout (KO) mice in vivo highlighted the critical role of ANGPTL4 in governing memory functions associated with various stem cell processes. This regulation occurred through histone H3 methylation alterations and PI3K/Akt signaling pathways in response to successive HPV antigen exposures. Furthermore, memory functions associated with various stem cell functions that were evident in wild-type mice following consecutive exposures to HPV antigen were not observed in ANGPTL4 KO mice. In summary, our findings strongly support the presence of memory mechanism in non-immune cells, particularly tissue-resident stem cells.

Exploring Memory Function Beyond Immune Cells: ANGPTL4-Mediated Memory Functions in Tissue Resident Stem Cells

Adapted immune cells are known to develop memory functions that increase resistance to subsequent infections after initial pathogen exposure, however, it is unclear whether non-immune cells, like tissue-resident stem cells, have similar memory functions. Here, it is found that tissue-resident stem cells crucial for tissue regeneration show diminished adverse effects on diverse stem cell functions against successive exposure to foreign antigen (β-glucan) to maintain tissue homeostasis and stability both in vitro and in vivo. These data suggest that endometrial stem cells may possess a robust memory function, in contrast, fully differentiated cells like fibroblasts and vesicular cells do not show these memory mechanisms upon consecutive antigen exposure. Moreover, the pivotal role of Angiopoietin-like 4 (ANGPTL4) in regulating the memory functions of endometrial stem cells is identified through specific shRNA knockdown in vitro and knockout mice in vivo experiments. ANGPTL4 is associated with the alteration of diverse stem cell functions and epigenetic modifications, notably through histone H3 methylation changes and two pathways (i.e., PI3K/Akt and FAK/ERK1/2 signaling) upon consecutive antigen exposure. These findings imply the existence of inherent self-defense mechanisms through which local stem cells can adapt and protect themselves from recurrent antigenic challenges, ultimately mitigating adverse consequences.

Glucocorticoids in lung cancer: Navigating the balance between immunosuppression and therapeutic efficacy

Glucocorticoids (GCs), a class of hormones secreted by the adrenal glands, are released into the bloodstream to maintain homeostasis and modulate responses to various stressors. These hormones function by binding to the widely expressed GC receptor (GR), thereby regulating a wide range of pathophysiological processes, especially in metabolism and immunity. The role of GCs in the tumor immune microenvironment (TIME) of lung cancer (LC) has been a focal point of research. As immunosuppressive agents, GCs exert a crucial impact on the occurrence, progression, and treatment of LC. In the TIME of LC, GCs act as a constantly swinging pendulum, simultaneously offering tumor-suppressive properties while diminishing the efficacy of immune-based therapies. The present study reviews the role and mechanisms of GCs in the TIME of LC.

Reliability and validity of the Chinese version of the COMPI Fertility Problem Stress Scale-Short Form for infertile women

OBJECTIVE

To translate and culturally adapt the COMPI Fertility Problem Stress Scale-Short form (COMPI-FPSS-SF) and to test its reliability and validity in China.

METHODS

The cross-sectional study adopted Brislin's translation model to translate, synthesize, back-translate, and cross-culturally adapt the COMPI-FPSS-SF for the Chinese setting. A total of 279 infertile women were invited to participate in the study to test the reliability and validity of the scale between March and June 2021.

RESULTS

It was verified that the Chinese version of the COMPI-FPSS-SF has three domains with nine items. The Cronbach's α coefficient of the total scale was 0.907, and the coefficient for each dimension ranged from 0.760 to 0.855. The test-retest validity was 0.891. The exploratory factor analysis extracted three common factors with eigenvalues of 4.499, 1.124, and 1.011 and a cumulative variance contribution of 73.706. The validity factor analysis showed good results for the three-factor structure fit. The criterion-related validity with the Fertility Inventory Short-Form Scale was 0.649. The above analysis revealed statistically significant differences (P < 0.001).

CONCLUSIONS

The Chinese version of the COMPI-FPSS-SF can be used for the assessment of fertility-related stress in infertility patients in China with good reliability and validity.

Identification and verification of characteristic differentially expressed ferroptosis-related genes in osteosarcoma using bioinformatics analysis

BACKGROUND

This study identified and verified the characteristic differentially expressed ferroptosis-related genes (CDEFRGs) in osteosarcoma (OS).

METHODS

We extracted ferroptosis-related genes (FRGs), identified differentially expressed FRGs (DEFRGs) in OS, and conducted correlation analysis between DEFRGs. Next, we conducted GO and KEGG analyses to explore the biological functions and pathways of DEFRGs. Furthermore, we used LASSO and SVM-RFE algorithms to screen CDEFRGs, and evaluated its accuracy in diagnosing OS through ROC curves. Then, we demonstrated the molecular function and pathway enrichment of CDEFRGs through GSEA analysis. In addition, we evaluated the differences in immune cell infiltration between OS and NC groups, as well as the correlation between CDEFRGs expressions and immune cell infiltrations. Finally, the expression of CDEFRGs was verified through qRT-PCR, western blotting, and immunohistochemistry experiments.

RESULTS

We identified 51 DEFRGs and the expression relationship between them. GO and KEGG analysis revealed their key functions and important pathways. Based on four CDEFRGs (PEX3, CPEB1, NOX1, and ALOX5), we built the OS diagnostic model, and verified its accuracy. GSEA analysis further revealed the important functions and pathways of CDEFRGs. In addition, there were differences in immune cell infiltration between OS group and NC group, and CDEFRGs showed significant correlation with certain infiltrating immune cells. Finally, we validated the differential expression levels of four CDEFRGs through external experiments.

CONCLUSIONS

This study has shed light on the molecular pathological mechanism of OS and has offered novel perspectives for the early diagnosis and immune-targeted therapy of OS patients.

Cyclic processes in the uterine tubes, endometrium, myometrium, and cervix: pathways and perturbations

This review leads the 2023 Call for Papers in MHR: 'Cyclical function of the female reproductive tract' and will outline the complex and fascinating changes that take place in the reproductive tract during the menstrual cycle. We will also explore associated reproductive tract abnormalities that impact or are impacted by the menstrual cycle. Between menarche and menopause, women and people who menstruate living in high-income countries can expect to experience ∼450 menstrual cycles. The primary function of the menstrual cycle is to prepare the reproductive system for pregnancy in the event of fertilization. In the absence of pregnancy, ovarian hormone levels fall, triggering the end of the menstrual cycle and onset of menstruation. We have chosen to exclude the ovaries and focus on the other structures that make up the reproductive tract: uterine tubes, endometrium, myometrium, and cervix, which also functionally change in response to fluctuations in ovarian hormone production across the menstrual cycle. This inaugural paper for the 2023 MHR special collection will discuss our current understanding of the normal physiological processes involved in uterine cyclicity (limited specifically to the uterine tubes, endometrium, myometrium, and cervix) in humans, and other mammals where relevant. We will emphasize where knowledge gaps exist and highlight the impact that reproductive tract and uterine cycle perturbations have on health and fertility.

DNA protein kinase promotes cellular senescence in dental follicle cells

OBJECTIVE

Short telomeres and genomic DNA damage are causes of cellular senescence in dental follicle cells (DFCs).

DESIGN

This study examined the role of the DNA damage response (DDR) during cellular senescence of DFCs by β-galactosidase activity and DNA damage by comet assay. Expression of genes/proteins was determined by Western Blots and reverse transcription-quantitative polymerase chain reaction, while glycolysis was enzymatically estimated. Cell cycle stages and reactive oxygen species (ROS) were investigated by flow cytometry.

RESULTS

During the induction of cellular senescence gene expression of DDR genes were down-regulated, while DNA double-strand breaks occurred at the same time. Furthermore, inhibition of DNA protein kinase (DNA-PK) reduced senescence and ROS, both of which are associated with cellular senescence. In contrast, while these data suggest that inhibition of DDR is associated with the induction of cellular senescence, inhibition of DNA-PK did not result in renewal of DFCs, as inhibition resulted in typical features of depleted cells such as increased cell size and reduced cell proliferation rate. DNA-PK repression inhibited both osteogenic differentiation potential and glycolysis, which are typical features of cellular exhaustion. Moreover, DNA-PK affects cellular senescence via activation of AKT1 (protein kinase B).

CONCLUSION

Our results suggest that DNA-PK promotes cellular senescence, but DFCs may control the induction of cellular senescence via down-regulation of DDR genes. However, we also showed that inhibition of DNA-PK cannot renew senescent DFCs.

NR3C1 and glucocorticoid-regulatory genes mRNA and protein expression in the endometrium and ampulla during the bovine estrous cycle

The bovine reproductive tract exhibits changes during the estrous cycle modulated by the interplay of steroid hormones. Glucocorticoids can be detrimental when stress-induced but are relevant at baseline levels for appropriate reproductive function. Here, an analysis of quantitative real-time PCR was performed to study the bovine glucocorticoid-related baseline gene transcription in endometrial and ampullar tissue samples derived from three time points of the estrous cycle, stage I (Days 1-4), stage III (Days 11-17) and stage IV (Days 18-20). Our results revealed expression differences during stages, as expression observed in the ampulla was higher during the post-ovulatory phase (stage I), including the glucocorticoid receptor NR3C1, and some of its regulators, involved in glucocorticoid availability (HSD11B1 and HSD11B2) and transcriptional actions (FKBP4 and FKBP5). In contrast, in the endometrium, higher expression of the steroid receptors was observed during the late luteal phase (stage III), including ESR1, ESR2, PGRMC1 and PGRMC2, and HSD11B1 expression decreased, while HSD11B2 increased. Moreover, at protein level, FKBP4 was higher expressed during the late luteal phase, and NR3C1 during the pre-ovulatory phase (stage IV). These results suggest that tight regulation of the glucocorticoid activity is promoted in the ampulla, when reproductive events are taking place, including oocyte maturation. Moreover, most expression changes in the endometrium were observed during the late luteal phase, and may be related to the embryonic maternal recognition. In conclusion, the glucocorticoid regulation changes across the estrous cycle and may be playing a role on the reproductive events occurring in the bovine ampulla and endometrium.

A novel role of follicle-stimulating hormone (FSH) in various regeneration-related functions of endometrial stem cells

Follicle-stimulating hormone (FSH) promotes the production and secretion of estrogen, which in turn stimulates the growth and maturation of ovarian follicles. Therefore, consecutive FSH treatment to induce ovarian hyperstimulation (superovulation) is still considered the most cost-effective option for the majority of assisted reproductive technologies (ARTs). However, a relatively high cancellation rate and subsequent low pregnancy outcomes (approximately 15%) are the most challenging aspects of this FSH-based ART. Currently, the main cause for this low implantation rate of FSH-based ART has not yet been revealed. Therefore, we hypothesized that these high cancellation rates with FSH-based superovulation protocols might be associated with the harmful effects of consecutive FSH treatment. Importantly, several recent studies have revealed that tissue-resident stem cell deficiency can significantly reduce cyclic endometrial regeneration and subsequently decrease the pregnancy outcome. In this context, we investigated whether FSH treatment could directly inhibit endometrial stem cell functions and consequently suppress endometrial regeneration. Consistent with our hypothesis, our results revealed for the first time that FSH could inhibit various regeneration-associated functions of endometrial stem cells, such as self-renewal, migration, and multilineage differentiation capacities, via the PI3K/Akt and ERK1/2 signaling pathways both in vitro and in vivo.

Follicle-stimulating hormone (FSH) is commonly administered to treat female infertility by stimulating the ovaries, but FSH treatment can also inhibit key cellular and physiological processes required for successful pregnancy. In the light of pregnancy outcomes as low as 15 percent after FSH-based assisted reproduction technologies, In-Sun Hong at Gachon University, Incheon, South Korea, and colleagues investigated the effects of FSH. Working with cultured human stem cells from the lining of the uterus, they found that FSH could inhibit multiple cellular regenerative functions that normally maintain this lining. They also identified a specific molecular signaling pathway involved in mediating these inhibitory effects. Studies in mice supported the cell culture results. The findings could help improve infertility treatment strategies by guiding research into methods to alleviate the unwanted effects of FSH.

Novel roles of luteinizing hormone (LH) in tissue regeneration-associated functions in endometrial stem cells

Luteinizing hormone (LH) stimulates the synthesis and secretion of the key steroid hormone estrogen, which subsequently promotes ovarian follicular growth and development. Therefore, the administration of exogenous LH to achieve superovulation (multiple ovulations) and an LH surge is commonly used as the most effective therapeutic option in a majority of in vitro fertilization (IVF) clinics. However, a relatively low pregnancy rate (between 20% and 35%) is one of the most challenging aspects of LH-based infertility treatment. Furthermore, the major cause of this low pregnancy rate in LH-based infertility treatment remains unidentified. Recent studies have shown that endometrial stem cell loss or deficiency can significantly decrease tissue regeneration ability during the menstrual cycle and reduce endometrial receptivity. In this context, we postulated that the low pregnancy rates following LH-based ovarian hyperactivation may be the result of the adverse effects of consecutive exogenous LH administration on endometrial stem cells. To the best of our knowledge, this study revealed for the first time that in addition to its previously reported roles in stimulating ovarian functions through the pituitary-gonadal axis, LH brings about the extragonadal suppression of various tissue regeneration-associated functions in endometrial stem cells, such as self-renewal, migration ability, multilineage differentiation potential, and pluripotency/stemness, by inhibiting pro-survival Akt and ERK1/2 signaling pathways in vitro and in vivo, and as a consequence, it decreases the endometrial receptivity.