Functional Enrichment Analysis of Tumor Microenvironment-Driven Molecular Alterations That Facilitate Epithelial-to-Mesenchymal Transition and Distant Metastasis.

Nowadays, hepatocellular carcinoma (HCC) is the second leading cause of cancer deaths, and identifying the effective factors in causing this disease can play an important role in its prevention and treatment. Tumors provide effective agents for invasion and metastasis to other organs by establishing appropriate communication between cancer cells and the microenvironment. Epithelial-to-mesenchymal transition (EMT) can be mentioned as one of the effective phenomena in tumor invasion and metastasis. Several factors are involved in inducing this phenomenon in the tumor microenvironment, which helps the tumor survive and migrate to other places. It can be effective to identify these factors in the use of appropriate treatment strategies and greater patient survival. This study investigated the molecular differences between tumor border cells and tumor core cells or internal tumor cells in HCC for specific EMT genes. Expression of NOTCH1, ID1, and LST1 genes showed a significant increase at the HCC tumor border. Targeting these genes can be considered as a useful therapeutic strategy to prevent distant metastasis in HCC patients.

Cell and cell-derivative-based therapy for liver diseases: current approaches and future promises.

INTRODUCTION: According to the recent updates from World Health Organization, liver diseases are the 12th most common cause of mortality. Currently, orthotopic liver transplantation (OLT) is the most effective and the only treatment for end-stage liver diseases. Owing to several shortcomings like finite numbers of healthy organ donors, lifelong immunosuppression, and complexity of the procedure, cell and cell-derivatives therapies have emerged as a potential therapeutic alternative for liver diseases. Various cell types and therapies have been proposed and their therapeutic effects evaluated in preclinical or clinical studies, including hepatocytes, hepatocyte-like cells (HLCs) derived from stem cells, human liver stem cells (HLSCs), combination therapies with various types of cells, organoids, and implantable cell-biomaterial constructs with synthetic and natural polymers or even decellularized extracellular matrix (ECM). AREAS COVERED: In this review, we highlighted the current status of cell and cell-derivative-based therapies for liver diseases. Furthermore, we discussed future prospects of using HLCs, liver organoids, and their combination therapies. EXPERT OPINION: Promising application of stem cell-based techniques including iPSC technology has been integrated into novel techniques such as gene editing, directed differentiation, and organoid technology. iPSCs offer promising prospects to represent novel therapeutic strategies and modeling liver diseases.

Kidney development and function: ECM cannot be ignored.

The extracellular matrix (ECM) is an essential network entity surrounding and supporting cells to guarantee their physiological function and homeostasis. It is important to choose the most appropriate ECM for in vitro experiments of mammalian cells for tissue engineering and functional analyses. Although most studies have examined optimization of the correct ECM that can be used to assess mammalian cells, a comprehensive study has not been conducted. In this review, we present the factors to be taken into consideration when designing or optimizing an appropriate ECM for development and maintenance of kidney tissues and compare the previously reported ECMs.

Human ovarian tissue in-vitro culture: primordial follicle activation as a new strategy for female fertility preservation.

Cryopreservation and transplantation of ovarian tissue is the only fertility preservation option used for prepubertal girls and women who don't have a chance for embryo or oocyte vitrification. For women with aggressive cancer, hormone-responsive malignancies, autoimmune diseases, etc. ovary transplantation cannot be performed so an alternative technology called in-vitro follicle activation is thinkable. In this method, dormant primordial follicles are activated from the resting primordial pool by in-vitro culture and enter their growth phase. Different in-vitro culture media and supplements in addition to various culturing methods have been conducted for activating these dormant follicles. Furthermore, several signaling pathways such as Hippo, phosphatidylinositol-3-kinase, and mTOR influence follicle activation. Therefore, the addition of different activators of these signaling pathways can beneficially regulate this culture system. This review summarizes the findings on different aspects of human ovarian tissue culture strategies for in-vitro follicular activation, their medium, and different factors involved in this activation. Afterward, signaling pathways important for follicle activation and their clinical applications towards improving activation in culture are also reviewed.

Kidney organoids: current knowledge and future directions.

The kidney is a highly complex organ in the human body. Although creating an in vitro model of the human kidney is challenging, tremendous advances have been made in recent years. Kidney organoids are in vitro kidney models that are generated from stem cells in three-dimensional (3D) cultures. They exhibit remarkable degree of similarities with the native tissue in terms of cell type, morphology, and function. The establishment of 3D kidney organoids facilitates a mechanistic study of cell communications, and these organoids can be used for drug screening, disease modeling, and regenerative medicine applications. This review discusses the cellular complexity during in vitro kidney generation. We intend to highlight recent progress in kidney organoids and the applications of these relatively new technologies.

Modeling Hepatotropic Viral Infections: Cells vs. Animals.

The lack of an appropriate platform for a better understanding of the molecular basis of hepatitis viruses and the absence of reliable models to identify novel therapeutic agents for a targeted treatment are the two major obstacles for launching efficient clinical protocols in different types of viral hepatitis. Viruses are obligate intracellular parasites, and the development of model systems for efficient viral replication is necessary for basic and applied studies. Viral hepatitis is a major health issue and a leading cause of morbidity and mortality. Despite the extensive efforts that have been made on fundamental and translational research, traditional models are not effective in representing this viral infection in a laboratory. In this review, we discuss in vitro cell-based models and in vivo animal models, with their strengths and weaknesses. In addition, the most important findings that have been retrieved from each model are described.

Evolution of organoid technology: Lessons learnt in Co-Culture systems from developmental biology.

In recent years, the development of 3D organoids has opened new avenues of investigation into development, physiology, and regenerative medicine. Organoid formation and the process of organogenesis share common developmental pathways; thus, our knowledge of developmental biology can help model the complexity of different organs to refine organoids into a more sophisticated platform. The developmental process is strongly dependent on complex networks and communication of cell-cell and cell-matrix interactions among different cell populations and their microenvironment, during embryogenesis. These interactions affect cell behaviors such as proliferation, survival, migration, and differentiation. Co-culture systems within the organoid technology were recently developed and provided the highly physiologically relevant systems. Supportive cells including various types of endothelial and stromal cells provide the proper microenvironment, facilitate organoid assembly, and improve vascularization and maturation of organoids. This review discusses the role of the co-culture systems in organoid generation, with a focus on how knowledge of developmental biology has directed and continues to shape the development of more evolved 3D co-culture system-derived organoids.

Promoting Maturation of Human Pluripotent Stem Cell-Derived Renal Microtissue by Incorporation of Endothelial and Mesenchymal Cells.

Directed differentiation of human pluripotent stem cells (hPSCs) uses a growing number of small molecules and growth factors required for in vitro generation of renal lineage cells. Although current protocols are relatively inefficient or expensive. The first objective of the present work was to establish a new differentiation protocol for generating renal precursors. We sought to determine if inducer of definitive endoderm 1 (IDE1), a cost-effective small molecule, can be used to replace activin A. Gene expression data showed significantly increased expressions of nephrogenic markers in cells differentiated with 20 nM IDE1 compared with cells differentiated with activin A. Thus, renal lineage cells could be generated by this alternative approach. Afterward, we determined whether coculture of endothelial and mesenchymal cells could increase the maturation of three-dimensional (3D) renal structures. For this purpose, we employed a 3D coculture system in which hPSC-derived kidney precursors were cocultured with endothelial cells (ECs) and mesenchymal stem cells (MSCs), hereafter named RMEM (renal microtissue derived from coculture of renal precursors with endothelial and mesenchymal stem cells). hPSC-derived kidney precursors were cultured either alone [renal microtissue (RM)] or in coculture with human umbilical vein endothelial cells and human bone marrow-derived mesenchymal stem cells at an approximate ratio of 10:7:2, respectively. Immunofluorescent staining showed expressions of kidney-specific markers synaptopodin, LTL, and E-cadherin, as well as CD31+ ECs that were distributed throughout the RMEMs. Quantitative real-time polymerase chain reaction analysis confirmed a significant increase in gene expressions of the renal-specific markers in RMEMs compared with RMs. These findings demonstrated that renal precursors cocultured with endothelial and MSCs showed greater maturity compared with RMs. Moreover, ex ovo transplantation induced further maturation in the RMEM constructs. Our novel approach enabled the generation of RMEM that could potentially be used in high-throughput drug screening and nephrotoxicology studies.

Engineering a Model to Study Viral Infections: Bioprinting, Microfluidics, and Organoids to Defeat Coronavirus Disease 2019 (COVID-19).

While the number of studies related to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) is constantly growing, it is essential to provide a framework of modeling viral infections. Therefore, this review aims to describe the background presented by earlier used models for viral studies and an approach to design an "ideal" tissue model for SARS-CoV-2 infection. Due to the previous successful achievements in antiviral research and tissue engineering, combining the emerging techniques such as bioprinting, microfluidics, and organoid formation are considered to be one of the best approaches to form in vitro tissue models. The fabrication of an integrated multi-tissue bioprinted platform tailored for SARS-CoV-2 infection can be a great breakthrough that can help defeat coronavirus disease in 2019.

Cellular and Molecular Mechanisms of Kidney Development: From the Embryo to the Kidney Organoid.

Development of the metanephric kidney is strongly dependent on complex signaling pathways and cell-cell communication between at least four major progenitor cell populations (ureteric bud, nephron, stromal, and endothelial progenitors) in the nephrogenic zone. In recent years, the improvement of human-PSC-derived kidney organoids has opened new avenues of research on kidney development, physiology, and diseases. Moreover, the kidney organoids provide a three-dimensional (3D) in vitro model for the study of cell-cell and cell-matrix interactions in the developing kidney. In vitro re-creation of a higher-order and vascularized kidney with all of its complexity is a challenging issue; however, some progress has been made in the past decade. This review focuses on major signaling pathways and transcription factors that have been identified which coordinate cell fate determination required for kidney development. We discuss how an extensive knowledge of these complex biological mechanisms translated into the dish, thus allowed the establishment of 3D human-PSC-derived kidney organoids.

Autosomal dominant polycystic kidney disease: Disrupted pathways and potential therapeutic interventions.

Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic inherited renal cystic disease that occurs in different races worldwide. It is characterized by the development of a multitude of renal cysts, which leads to massive enlargement of the kidney and often to renal failure in adulthood. ADPKD is caused by a mutation in PKD1 or PKD2 genes encoding the proteins polycystin-1 and polycystin-2, respectively. Recent studies showed that cyst formation and growth result from deregulation of multiple cellular pathways like proliferation, apoptosis, metabolic processes, cell polarity, and immune defense. In ADPKD, intracellular cyclic adenosine monophosphate (cAMP) promotes cyst enlargement by stimulating cell proliferation and transepithelial fluid secretion. Several interventions affecting many of these defective signaling pathways have been effective in animal models and some are currently being tested in clinical trials. Moreover, the stem cell therapy can improve nephropathies and according to studies were done in this field, can be considered as a hopeful therapeutic approach in future for PKD. This study provides an in-depth review of the relevant molecular pathways associated with the pathogenesis of ADPKD and their implications in development of potential therapeutic strategies.