Human pituitary development and application of iPSCs for pituitary disease

Hypogonadotropic hypogonadism as a cause of NOA and its treatment

ABSTRACT

Hypogonadotropic hypogonadism (HH) represents a relatively rare cause of nonobstructive azoospermia (NOA), but its knowledge is crucial for the clinical andrologists, as it represents a condition that can be corrected with medical therapy in 3 quarters of cases. There are forms of congenital HH, whether or not associated with an absent sense of smell (anosmic HH or Kallmann syndrome, and normosmic HH, respectively), and forms of acquired HH. In congenital HH, complete absence of pubertal development is characteristic. On the other hand, if the deficit occurs after the time of pubertal development, as in acquired HH patients, infertility and typical symptoms of late-onset hypogonadism are the main reasons for seeking medical assistance. Gonadotropin-releasing hormone (GnRH) or gonadotropin replacement therapy is the mainstay of drug therapy and offers excellent results, although a small but significant proportion of patients do not achieve sufficient responses.

Benchmark for Setting ACTH Cell Dosage in Clinical Regenerative Medicine for Post-Operative Hypopituitarism

BACKGROUND/OBJECTIVES

Our objective is to develop hormone-producing pituitary cells that can function in the same manner as the human body and provide more effective treatments than current hormone replacement therapy. We have already established a technique for generating hypothalamic-pituitary organoids using feeder-free human pluripotent stem cells (hPSCs) and demonstrated their effectiveness in vivo through transplantation into hypopituitary mouse models. To prospectively determine the upper limit of transplanting adenohypophyseal cells into humans, we investigated the human maximum secretion capacity of adrenocorticotropic hormone (ACTH) and growth hormone (GH).

METHODS

We analyzed data from 28 patients with pituitary adenomas, among whom 16 evinced no abnormality of ACTH secretion and 12 showed no GH secretion on corticotropin-releasing hormone (CRH) and growth hormone-releasing hormone-2 (GHRP-2) stimulation testing.

RESULTS

The average ACTH peak value after CRH stimulation tests was 97.2 pg/mL, and the average GH peak value after GHRP-2 stimulation tests was 25.1 ng/mL.

CONCLUSIONS

These data will likely serve as benchmarks of ACTH and GH secretion when transplanting cultured cells into humans.

Human Pituitary Organoids: Transcriptional Landscape Deciphered by scRNA-Seq and Stereo-Seq, with Insights into SOX3's Role in Pituitary Development

The 3D human pituitary organoid represents a promising laboratory model for investigating human pituitary diseases. Nonetheless, this technology is still in its nascent stage, with uncertainties regarding the cellular composition, intercellular interactions, and spatial distribution of the human pituitary organoids. To address these gaps, the culture conditions are systematically adjusted and the efficiency of induced pluripotent stem cells' (iPSCs') differentiation into pituitary organoids is successfully improved, achieving results comparable to or exceeding those of previous studies. Additionally, single-cell RNA-sequencing (scRNA-seq) and stereomics sequencing (Stereo-seq) are performed on the pituitary organoids for the first time, and unveil the diverse cell clusters, intricate intercellular interactions, and spatial information within the organoids. Furthermore, the SOX3 gene interference impedes the iPSCs' differentiation into pituitary organoids, thereby highlighting the potential of pituitary organoids as an ideal experimental model. Altogether, the research provides an optimized protocol for the human pituitary organoid culture and a valuable transcriptomic dataset for future explorations, laying the foundation for subsequent research in the field of pituitary organoids or pituitary diseases.

Progress, challenges and perspectives in the management of hypopituitarism

Hypopituitarism is a rare endocrine disorder characterized by insufficient hormone secretion from the pituitary gland. This condition leads to deficient production of one or more pituitary hormones, including growth hormone (GH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), adrenocorticotropic hormone (ACTH), and antidiuretic hormone (ADH), also called arginine vasopressin (AVP). Symptoms vary widely and are often not, late recognized.Diagnosis typically involves a thorough clinical evaluation, hormone level assessments, and neuroimaging studies to identify underlying causes. Treatment aims to replace deficient hormones and address the underlying cause and related complications when possible. In this special issue we address diagnosis, comorbidities, and management of hypopituitarism. We hope that it will help healthcare professionals to manage their patients.

Pathogenesis, clinical features, and treatment of plurihormonal pituitary adenoma

Plurihormonal pituitary adenoma (PPA) is a type of pituitary tumor capable of producing two or more hormones and usually presents as an aggressive, large adenoma. As yet, its pathogenesis remains unclear. This is the first study to systematically summarize the underlying pathogenesis of PPA. The pathogenesis is related to plurihormonal primordial stem cells, co-transcription factors, hormone co-expression, differential gene expression, and cell transdifferentiation. We conducted a literature review of PPA and analyzed its clinical characteristics. We found that the average age of patients with PPA was approximately 40 years, and most showed only one clinical symptom. The most common manifestation was acromegaly. Currently, PPA is treated with surgical resection. However, recent studies suggest that immunotherapy may be a potentially effective treatment.

Clinical features of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis: a new aspect of paraneoplastic autoimmune condition

The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.

Mitophagy involved the biological processes of hormones

Mitochondria fulfill vital functions in energy production, maintaining ion balance, and facilitating material metabolism. Mitochondria are sacrificed to protect cells or induce apoptosis when the body is under stress. The regulatory pathways of mitophagy include both ubiquitin-dependent and non-dependent pathways. The involvement of mitophagy has been demonstrated in the onset and progression of numerous diseases, highlighting its significant role. Endocrine hormones are chemical substances secreted by endocrine organs or endocrine cells, which participate in the regulation of physiological functions and internal environmental homeostasis of the body. Imbalances in endocrine hormones contribute to the development of various diseases. However, the precise impact of mitophagy on the physiological and pathological processes involving endocrine hormones remains unclear. This article aims to comprehensively overview recent advancements in understanding the mechanisms through which mitophagy regulates endocrine hormones.

Derivation of Human Salivary Epithelial Progenitors from Pluripotent Stem Cells via Activation of RA and Wnt Signaling

Derivation of salivary gland epithelial progenitors (SGEPs) from human pluripotent stem cells (hPSCs) has great potential in developmental biology and regenerative medicine. At present, no efficient method is available to generate salivary gland cells from hPSCs. Here, we described for the first time a robust protocol for direct differentiation of hPSCs into SGEPs by mimicking retinoic acid and Wnt signaling. These hPSC-derived SGEPs expressed SOX9, KRT5, and KRT19, important progenitor markers of developing salivary glands. CD24 and α-SMA positive cells, capable of restoring the functions of injured salivary glands, were also present in SGEP cultures. Importantly, RNA-sequencing revealed that the SGEPs resembled the transcript profiles of human fetal submandibular glands. Therefore, we provided an efficient protocol to induce hPSCs differentiation into SGEPs. Our study provides a foundation for generating functional hPSCs derived salivary gland acinar cells and three-dimensional organoids, potentially serving as new models for basic study and future translational research.

Retinoic acid and FGF10 promote the differentiation of pluripotent stem cells into salivary gland placodes

Background

Salivary glands produce saliva that play essential roles in digestion and oral health. Derivation of salivary gland organoids from pluripotent stem cells (PSCs) provides a powerful platform to model the organogenesis processes during development. A few studies attempted to differentiate PSCs into salivary gland organoids. However, none of them could recapitulate the morphogenesis of the embryonic salivary glands, and most of the protocols involved complicated manufacturing processes.

Methods

To generate PSC-derived salivary gland placodes, the mouse embryonic stem cells were first differentiated into oral ectoderm by treatment with BMP4 on day 3. Retinoic acid and bFGF were then applied to the cultures from day 4 to day 6, followed by a 4-day treatment of FGF10. The PSC-derived salivary gland placodes on day 10 were transplanted to kidney capsules to determine the regenerative potential. Quantitative reverse transcriptase–polymerase chain reaction, immunofluorescence, and RNA-sequencing were performed to identify the PSC-derived SG placodes.

Results

We showed that step-wise treatment of retinoic acid and FGF10 promoted the differentiation of PSCs into salivary gland placodes, which can recapitulate the early morphogenetic events of their fetal counterparts, including the thickening, invagination, and then formed initial buds. The PSC-derived salivary gland placodes also differentiated into developing duct structures and could develop to striated and excretory ducts when transplanted in vivo.

Conclusions

The present study provided an easy and safe method to generate salivary gland placodes from PSCs, which offered possibilities for studying salivary gland development in vitro and developing new cell therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03033-5.

Disease Modeling of Pituitary Adenoma Using Human Pluripotent Stem Cells

Simple Summary

Pituitary adenoma pathophysiology has been studied mainly using murine cell lines, animal models, and pituitary tumor samples. However, the lack of human pituitary cell line is a significant limiting factor in studying the molecular mechanisms of human pituitary tumors. Recently, pituitary induction methods from human-induced pluripotent stem cells (hiPSCs) have been established. These methods can induce human pituitary hormone-producing cells that retain physiological properties. hiPSCs in which tumor-causing gene mutations are introduced using genome-editing techniques, such as CRISPR/Cas9 systems, provide great opportunities to establish in vitro human pituitary adenoma disease models. The models will be a novel platform to discover novel drugs and investigate tumorigenesis and pathophysiology. The purpose of this review is to provide an overview of the applications of iPSCs for pituitary and neoplastic disorder research and genome-editing technologies to create strategies for developing pituitary adenoma models using iPSCs.

Abstract

Pituitary adenomas are characterized by abnormal growth in the pituitary gland. Surgical excision is the first-line treatment for functional (hormone-producing) pituitary adenomas, except for prolactin-producing adenomas; however, complete excision is technically challenging, and many patients require long-term medication after the treatment. In addition, the pathophysiology of pituitary adenomas, such as tumorigenesis, has not been fully understood. Pituitary adenoma pathophysiology has mainly been studied using animal models and animal tumor-derived cell lines. Nevertheless, experimental studies on human pituitary adenomas are difficult because of the significant differences among species and the lack of reliable cell lines. Recently, several methods have been established to differentiate pituitary cells from human pluripotent stem cells (hPSCs). The induced pituitary hormone-producing cells retain the physiological properties already lost in tumor-derived cell lines. Moreover, CRISPR/Cas9 systems have expedited the introduction of causative gene mutations in various malignant tumors into hPSCs. Therefore, hPSC-derived pituitary cells have great potential as a novel platform for studying the pathophysiology of human-specific pituitary adenomas and developing novel drugs. This review presents an overview of the recent progresses in hPSC applications for pituitary research, functional pituitary adenoma pathogenesis, and genome-editing techniques for introducing causative mutations. We also discuss future applications of hPSCs for studying pituitary adenomas.