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Epithelial histology of the cervix. Coronal section of the cervix with a detailed visualization of epithelia, from vagina to isthmus: ectocervix, original squamocolumnar junction (SCJ), new SCJ, endocervix.
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The pelviperineal organs of the female reproductive tract form an essential cornerstone of human procreation. The system comprises the ectodermal external genitalia, the Müllerian upper-vaginal, cervical, endometrial and oviductal derivatives, and the endodermal ovaries. Each of these organs presents with a unique course of biological development a...
Citations
... Cluster 1, identified as the lamina propria, provides a unique microenvironment crucial for vaginal epithelial proliferation, differentiation and maintenance [9,12,[38][39][40][41][42]. It is distinguished from the vaginal epithelium by a delicate basement membrane primarily composed of extracellular matrix (ECM) [8]. ...
... Gene Ontology (GO) analysis of the DEGs indicated a notable angiogenic tendency (Supplementary Figure S2C). Immunohistochemical staining confirmed angiogenesis, as indicated by the presence of CD31, CD34, and VWF (von Willebrand factor) [40,41] (Supplementary Figure S2D). This finding aligns with prior studies highlighting the rich vascular network complexity of the vagina [41]. ...
... Cells colabelled with MKI67 and subjected to SOX2 immunofluorescence were observed in the basal region ( Figure 7B). TP63, a master regulator of stratified epithelia responsible for initiating the stratification program and maintaining the selfrenewal capacity of stratified epithelial stem cells [40,58,59], is located specifically in the basal region of the vaginal epithelium. A significant overlap was observed between MKI67-positive and TP63-positive epithelial cells ( Figure 7C). ...
The human vaginal epithelium is a crucial component of numerous reproductive processes and serves as a vital protective barrier against pathogenic invasion. Despite its significance, a comprehensive exploration of its molecular profiles, including molecular expression and distribution across its multiple layers, has not been performed. In this study, we perform a spatial transcriptomic analysis within the vaginal wall of human fetuses to fill this knowledge gap. We successfully categorize the vaginal epithelium into four distinct zones based on transcriptomic profiles and anatomical features. This approach reveals unique transcriptomic signatures within these regions, allowing us to identify differentially expressed genes and uncover novel markers for distinct regions of the vaginal epithelium. Additionally, our findings highlight the varied expressions of keratin ( KRT) genes across different zones of the vaginal epithelium, with a gradual shift in expression patterns observed from the basal layer to the surface/superficial layer. This suggests a potential differentiation trajectory of the human vaginal epithelium, shedding light on the dynamic nature of this tissue. Furthermore, abundant biological processes are found to be enriched in the basal zone by KEGG pathway analysis, indicating an active state of the basal zone cells. Subsequently, the expressions of latent stem cell markers in the basal zone are identified. In summary, our research provides a crucial understanding of human vaginal epithelial cells and the complex mechanisms of the vaginal mucosa, with potential applications in vaginal reconstruction and drug delivery, making this atlas a valuable tool for future research in women's health and reproductive medicine.
... These leukocytes serve multiple roles, including immunoprotection as the endometrium prepares for implantation, regulation of trophoblast invasion, and in the absence of pregnancy, breakdown of endometrial tissue in the menstrual phase via secretion of matrix metalloproteinases (Mihm et al., 2011). Towards the end of the secretory phase, prior to the onset of menses, the endometrium has differentiated into three zones: the deepest layer remains the unchanged basalis layer, the middle layer is the stratum spongiosum, or loose edematous stroma containing tightly coiled spiral vessels and dilated glands, and the most superficial layer is the more stromally dense stratum compactum (Heremans et al., 2021). A hallmark of endometrial remodeling in the secretory phase is the transition of endometrial stromal fibroblasts into epithelioid-like decidualized stromal cells, characterized by increasing amounts of glycogen and lipids, and an expanded cytoplasm (Owusu-Akyaw et al., 2019). ...
Until recently, the study of age-related decline in fertility has focused primarily on the ovary; depletion of the finite pool of oocytes and increases in meiotic errors leading to oocyte aneuploidy are well-established mechanisms by which fertility declines with advancing age. Comparatively little is known about the impact of age on endometrial function. The endometrium is a complex tissue comprised of many cell types, including epithelial, stromal, vascular, immune and stem cells. The capacity of this tissue for rapid, cyclic regeneration is unique to this tissue, undergoing repeated cycles of growth and shedding (in the absence of an embryo) in response to ovarian hormones. Furthermore, the endometrium has been shown to be capable of supporting pregnancies beyond the established boundaries of the reproductive lifespan. Despite its longevity, molecular studies have established age-related changes in individual cell populations within the endometrium. Human clinical studies have attempted to isolate the effect of aging on the endometrium by analyzing pregnancies conceived with euploid, high quality embryos. In this review, we explore the existing literature on endometrial aging and its impact on pregnancy outcomes. We begin with an overview of the principles of endometrial physiology and function. We then explore the mechanisms behind endometrial aging in its individual cellular compartments. Finally, we highlight lessons about endometrial aging gleaned from rodent and human clinical studies and propose opportunities for future study to better understand the contribution of the endometrium to age-related decline in fertility.
... Similar to hESCs, patientderived iPSCs have the potential to differentiate into a variety of cell types, including neurons [112], hematopoietic cells [113], cardiomyocytes [114], glia cells [115], and pancreatic islets [116]. Furthermore, three-dimensional (3D) "organoid" models of female reproductive tissue, such as the uterus, fallopian tubes, ovaries, and trophoblast, all produced from iPSCs, have recently emerged as a valuable tool for simulating the physiological processes involved in the progression of gynecological diseases in vitro [117][118][119][120][121]. ...
Polycystic ovary syndrome (PCOS) is the most prevalent endocrine condition among women with pleiotropic sequelae possessing reproductive, metabolic, and psychological characteristics. Although the exact origin of PCOS is elusive, it is known to be a complex multigenic disorder with a genetic, epigenetic, and environmental background. However, the pathogenesis of PCOS, and the role of genetic variants in increasing the risk of the condition, are still unknown due to the lack of an appropriate study model. Since the debut of induced pluripotent stem cell (iPSC) technology, the ability of reprogrammed somatic cells to self-renew and their potential for multidirectional differentiation have made them excellent tools to study different disease mechanisms. Recently, researchers have succeeded in establishing human in vitro PCOS disease models utilizing iPSC lines from heterogeneous PCOS patient groups (iPSC PCOS ). The current review sets out to summarize, for the first time, our current knowledge of the implications and challenges of iPSC technology in comprehending PCOS pathogenesis and tissue-specific disease mechanisms. Additionally, we suggest that the analysis of polygenic risk prediction based on genome-wide association studies (GWAS) could, theoretically, be utilized when creating iPSC lines as an additional research tool to identify women who are genetically susceptible to PCOS. Taken together, iPSC PCOS may provide a new paradigm for the exploration of PCOS tissue-specific disease mechanisms.
Graphical Abstract
... Since the human female reproductive system and its associated microbiome differ drastically from that of other mammals and even primates [117], the usefulness of animal models is limited. However, human cell-culture-based model systems, including organoids [118], 3D vaginal epithelial and cervical cell-line models [41,42,119], and even 'vagina-on-a-chip' microfluidic platforms [120] are useful tools for mechanistic studies. The 'vagina-on-a-chip' system is particularly promising for pre-clinical studies of host-microbe interactions, as it retains many key characteristics of the human vaginal epithelium, including maintenance of acidic pH when colonised predominantly by L. crispatus, and conversely, increase in pH and secretion of inflammatory cytokines in the presence of G. vaginalis and 'BV-like' microbial communities. ...
Over the last two decades, sequencing-based methods have revolutionised our understanding of niche-specific microbial complexity. In the lower female reproductive tract, these approaches have enabled identification of bacterial compositional structures associated with health and disease. Application of metagenomics and metatranscriptomics strategies have provided insight into the putative function of these communities but it is increasingly clear that direct measures of microbial and host cell function are required to understand the contribution of microbe-host interactions to pathophysiology. Here we explore and discuss current methods and approaches, many of which rely upon mass-spectrometry, being used to capture functional insight into the vaginal mucosal interface. In addition to improving mechanistic understanding, these methods offer innovative solutions for the development of diagnostic and therapeutic strategies designed to improve women's health.
... This prompted a thorough examination of family documents. Following that, Lynch and Anne Krush, a medical social worker, travelled to Germany, where the majority of Family G originated, and gathered additional evidence of cancer propensity (Hampel, et al. [7]). ...
Lynch syndrome (LS) is an autosomal dominant genetic condition caused by mutations in the DNA mismatch repair (MMR) genes in the germline. Colorectal cancer and/or LS-associated cancer are more likely in people who carry pathogenic mutations in these genes. Cancers of the endometrium, small intestine, stomach, pancreas, and biliary tract, ovarian, brain, upper urinary tract, and skin are among the cancer types linked to LS. The criteria for a clinical diagnosis of LS, as well as the processes for genetic testing to identify carriers of pathogenetic mutations in MMR genes, have been known for a long time. The precise description of the pathogenicity associated with MMR genetic variants is critical in the mutation detection analysis, especially in order to enroll mutation carriers in endoscopic surveillance programs that are more suited to them. As a result, this may aid in the improvement of LS-related cancer prevention efforts. In this review, we discuss recent advances in the molecular genetics of LS.
... Hypothesis testing for FRT tissues has depended on two-dimensional (2D) models (such as cell lines) for many years, alongside short-term three-dimensional (3D) in vitro cell-culture and in vivo explant systems. However, it wasn't until 2009 that the idea of a total shift to long-term 3D in vitro cell-culturing technologies was envisioned (Heremans, et al. [7]). Numerous biological insights have been gained through 2D cultivation of immortalized cell lines or those generated from cancer in organs of interest. ...
Hormones must be balanced and dynamically controlled for the Female Reproductive Tract (FRT) to function correctly during the menstrual cycle, pregnancy, and delivery. Gamete selection and successful transfer to the uterus, where it implants and pregnancy occurs, is supported by the mucosal epithelial lining of the FRT ovaries, uterus, cervix, fallopian tubes, and vagina. Successful implantation and placentation in humans and other animals rely on complex interactions between the embryo and a receptive female reproductive system. The FRT's recent breakthroughs in three-dimensional (3D) organoid systems now provide critical experimental models that match the organ's physiological, functional, and anatomical characteristics in vitro. (Haycock, [1]). This article summarizes the current state of the art on organoids generated from various parts of the FRT. The current analysis examines recent developments in the creation of organoid models of reproductive organs, as well as their future directions.
... In summary, endometrial hydrogels overcome a major limitation of organoid technology and greatly expand the applicability of organoids to understand endometrial biology and associated pathologies. endometrium j organoid j uterus j hydrogels j ECM Recent studies have highlighted the significance of organoid technology in understanding human development and diseases (1,2). Organoids have provided us an opportunity to study human developmental processes, such as early embryonic development and implantation, that were not investigated in detail due to ethical reasons (3). ...
... For example, rectal organoids are currently used in identifying patients that would benefit from cystic fibrosis transmembrane conductance regulator-modulating drugs (4). Human endometrial organoids have been developed from healthy and disease tissue biopsies (1). Endometrial epithelial cells embedded in a small drop of Matrigel supplemented with activators or inhibitors of WNT, EGF, FGF, BMP, TGFβ, and ROCK signaling in the culture medium allow the development of endometrial organoids from single cells in a time-dependent manner (5)(6)(7). ...
... Under high Wnt culture conditions, endometrial stem/progenitor cells form endometrial organoids (44,47). In the past few years, endometrial organoids have been developed from normal and abnormal human endometrium (1,48). These organoids replicate many endometrial physiological functions, including histological and secretory changes associated with cyclical hormonal variations, and have already provided unique insights into the pathogenesis of human endometrial diseases, such as endometriosis, adenomyosis, and endometrial cancer (49). ...
Organoid technology has provided unique insights into human organ development, function, and diseases. Patient-derived organoids are increasingly used for drug screening, modeling rare disorders, designing regenerative therapies, and understanding disease pathogenesis. However, the use of Matrigel to grow organoids represents a major challenge in the clinical translation of organoid technology. Matrigel is a poorly defined mixture of extracellular matrix proteins and growth factors extracted from the Engelbreth–Holm–Swarm mouse tumor. The extracellular matrix is a major driver of multiple cellular processes and differs significantly between tissues as well as in healthy and disease states of the same tissue. Therefore, we envisioned that the extracellular matrix derived from a native healthy tissue would be able to support organoid growth akin to organogenesis in vivo. Here, we have developed hydrogels from decellularized human and bovine endometrium. These hydrogels supported the growth of mouse and human endometrial organoids, which was comparable to Matrigel. Organoids grown in endometrial hydrogels were proteomically more similar to the native tissue than those cultured in Matrigel. Proteomic and Raman microspectroscopy analyses showed that the method of decellularization affects the biochemical composition of hydrogels and, subsequently, their ability to support organoid growth. The amount of laminin in hydrogels correlated with the number and shape of organoids. We also demonstrated the utility of endometrial hydrogels in developing solid scaffolds for supporting high-throughput, cell culture–based applications. In summary, endometrial hydrogels overcome a major limitation of organoid technology and greatly expand the applicability of organoids to understand endometrial biology and associated pathologies.
... Although mice and epithelial cell models have been developed, study of the VMB is hampered by the lack of better models, as even nonhuman primates have vaginal physiology that differs greatly from that of the human female reproductive tract. In the absence of good animal models, establishment of three-dimensional (3D) organoid models would advance the field significantly (263). Most of the abundant taxa in the VMB are culturable, e.g., G. vaginalis (110), S. amnii (106), A. vaginae (264), and P. bivia (264), but other taxa, e.g., BVAB1 and "Ca. ...
The microbiome of the female reproductive tract defies the convention that high biodiversity is a hallmark of an optimal ecosystem. Although not universally true, a homogeneous vaginal microbiome composed of species of Lactobacillus is generally associated with health, whereas vaginal microbiomes consisting of other taxa are generally associated with dysbiosis and a higher risk of disease. The past decade has seen a rapid advancement in our understanding of these unique biosystems. Of particular interest, substantial effort has been devoted to deciphering how members of the microbiome of the female reproductive tract impact pregnancy, with a focus on adverse outcomes, including but not limited to preterm birth. Herein, we review recent research efforts that are revealing the mechanisms by which these microorganisms of the female reproductive tract influence gynecologic and reproductive health of the female reproductive tract.
... Much of the progress is hindered by the limitations of current model systems. We have seen new advancements in endometrial organoid technology, reviewed by others [10][11][12][13][14] , as well as in microfluidic culture platforms 15,16 . These tools are now beginning to improve our understanding of the mechanisms of endometrial diseases. ...
... Menstrual flow-derived organoids could also be used for precision medicine, such as determining endometrial sensitivity to chemotherapeutic agents. There have been many reviews on endometrial organoid technology in the past couple of years and the technology itself is readily used by many in the field [10][11][12][13][14]51 . ...
Each month during a woman's reproductive years, the endometrium undergoes vast changes to prepare for a potential pregnancy. Diseases of the endometrium arise for numerous reasons, many of which remain unknown. These endometrial diseases, including endometriosis, adenomyosis, endometrial cancer and Asherman syndrome, affect many women, with an overall lack of efficient or permanent treatment solutions. The challenge lies in understanding the complexity of the endometrium and the extensive changes, orchestrated by ovarian hormones, that occur in multiple cell types over the period of the menstrual cycle. Appropriate model systems that closely mimic the architecture and function of the endometrium and its diseases are needed. The emergence of organoid technology using human cells is enabling a revolution in modelling the endometrium in vitro. The goal of this Review is to provide a focused reference for new models to study the diseases of the endometrium. We provide perspectives on the power of new and emerging models, from organoids to microfluidics, which have opened up a new frontier for studying endometrial diseases.
... However, studies focused on details intrinsic to the epithelial cells are particularly challenging for 2 main reasons: 1) Biochemical characterization of clinical samples is limited because of the invasive process of endometrial biopsy required to obtain samples from healthy volunteers; and 2) although uterine stromal cells can be cultured and studied, epithelial cells have proven difficult to culture in a model that recapitulates their biological environment and function. The recent development of organoid culture has provided a system in which endometrial epithelial cells can be grown and studied in vitro (26). Established protocols describe isolation and culture of epithelial cells from endometrial biopsies, which are stimulated to proliferate by estrogen treatment (27)(28)(29). ...
Endometrial health is impacted by molecular processes that underlie estrogen responses. We assessed estrogen regulation of endometrial function by integrating the estrogen receptor alpha (ESR1) cistromes and transcriptomes of endometrial biopsies taken from the proliferative and mid-secretory phases of the menstrual cycle together with hormonally stimulated endometrial epithelial organoids. The cycle stage specific ESR1 binding sites were determined by ChIPseq and then integrated with changes in gene expression from RNAseq data to infer candidate ESR1 targets in normal endometrium. Genes with ESR1 binding in whole endometrium were enriched for chromatin modification and regulation of cell proliferation. The distribution of ESR1 binding sites in organoids was more distal from gene promoters when compared to primary endometrium and was more similar to the proliferative than the mid-secretory phase ESR1 cistrome. Inferred organoid estrogen/ESR1 candidate target genes impacted formation of cellular protrusions, and chromatin modification. Comparison of signaling impacted by candidate ESR1 target genes in endometrium vs. organoids reveals enrichment of both overlapping and distinct responses. Our analysis of the ESR1 cistromes and transcriptomes from endometrium and organoids provides important resources for understanding how estrogen impacts endometrial health and function.
